A Framework for Fitness-for-Purpose and Reuse in Computational Phenotyping
November 17, 2025
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Background
Bacterial infections have a huge impact on public health. These diseases can result either from bacterium itself or from the host’s reaction to its presence. Infections may then result at any body site and be water-borne, food-borne, vector-borne, and air-borne. The common modes of transmission for bacteria are direct contact, vectors, contaminated vehicles, airborne, and droplets. Such morbidity and mortality were strictly observed, which includes water treatment, immunization of both human beings and animals, practicing safe sex, and good personal hygiene. The increased resistance by bacteria to some antibiotics further supports the use of antibiotics with extreme care and caution.Â
The development of bacterial infections and diseases is influenced by several factors, including pathogenicity, virulence and infectivity. Infectivity refers to the organism’s ability to spread to susceptible individuals, pathogenicity assesses its potential to cause disease, and virulence indicates the severity of the disease it can produce. Host factors, such as nutritional status, age, duration of exposure, and genetic predisposition may also impact the disease progression. Additionally, environmental factors like air pollution and chemical exposures can weaken the body’s defences against bacterial infections.Â
Epidemiology
The external environment usually provides the site for contact between the bacterial agent and the host and where infections are ultimately obtained. There are various ways in which the bacteria are able to be transmitted to human beings, including water, food, air, and even living vectors. The transmission of bacteria is affected by both macro and microenvironments. For example, there are specific settings like jails and hospitals that may be hosting some unique types of bacteria. Some bacteria may also be relatively uncommon or even totally absent in other different geographical regions.Â
Anatomy
Pathophysiology
Human reservoirs: Bacterial infections are often transmitted through humans because they themselves act as a vector by harboring the disease but not showing any symptoms. An example of a passive carrier is Neisseria meningitidis, which harbors the bacterium in its respiratory tract. During the incubating period, the virus may be transmitted due to incubator carriers. The asymptomatic individuals also transmit sexually transmitted diseases. During the time when the individual is recovering, the convalescent carriers transmit the organism. Active carriers carry the organism in their body indefinitely after recovering from the illness. The Salmonella, especially Salmonella Typhi, may form a chronic carrier status without symptoms in the individual. From thereon, the carriers may transmit the pathogen to their contacts, continuously. Mary Mallon is a cook in New York City who was responsible for many typhoid disease outbreaks.Â
Animal reservoirs: Some zoonotic diseases that can enter and infect human beings and cause diseases through direct contact, ingestion, inhalation, or bites from animal reservoirs include Bacillus anthracis anthrax, Lyme disease, Francisella tularensis tularemia, and Salmonella diarrhea caused by Borrelia. Since zoonotic overflow occurs as a cycle of transmission between the tick hosts and animal hosts such as deer and mice. This overflow allows for infected ticks to overflow from the natural cycle of infection into humans and hence, is an important event in zoonotic diseases. In New England, it has been found that culling the deer infected with this disease on an island will almost eliminate human infection and also significantly reduce the ticks that are infected.Â
Arthropod reservoirs: Arthropods are the reservoirs for diseases. They transmit infection by the vector. It includes the flies, fleas, and lice that carry on the diseases. The bacterium Borrelia infects ticks, and after the blood meal from an infected animal, they introduce it into human beings. Other diseases that are caused by arthropod association include murine, Rocky Mountain spotted fever, scrub, bubonic plague, and typhus epidemica. These are transmitted by mites, mice, infected deer, or ticks.Â
Non-living reservoirs: Finally, air can get contaminated by some pathogenic bacteria, like tuberculosis that are transported by air currents. Soil acts as a reservoir for spore-forming bacteria like Clostridium, that causes tetanus, botulism, and gas gangrene. Poorly handled food, including milk, will act as a reservoir for several pathogenic organisms. Botulism can result from food contamination by feces, infected animals, or Botulinum spores. Food handlers harbor bacteria on their hands, and stringent regulations are followed to protect public health. Uncooked foods such as alfalfa and raw seed sprouts may also serve as the reservoir for bacterial infections. Water may also serve as a reservoir of infection following contamination by soil microbes or animal or human faeces or raw sewage. Inanimate objects such as doorknobs and toilet seats and utensils transmit infection indirectly. Many respiratory infections are not directly transmitted by aerosol, but by respiratory secretions being deposited on surfaces and hands and having secondary transmission by hand-to-mouth contact.Â
Etiology
Modes of transmissionÂ
Bacterial infections can be transmitted through five primary modes namely airborne, contact, droplet, vehicular and vectors which includes contaminated food, fomites and water.Â
Contact transmission: Transmission through contact involve es mucous membrane-to-mucous membrane contact or direct skin-to-skin contact, as well as fecal- oral transmission of intestinal bacteria. Additionally, bacterial infections such as syphilis can be spread through transfusions of contaminated blood products.Â
Airborne transmission: Certain bacteria are carried by air currents in droplet nuclei, allowing them to travel significant distances from their source. For instance, tuberculosis, Legionella, and Q fever can spread over long distances. In some cases, animals with Q fever have been known to transmit the infection to other animals up to 10 miles away.Â
Droplet transmission: When an infection is spread through droplets larger than 5µm in diameter, it is not classified as airborne because such droplets typically do not travel more than 1m through air. These larger droplets are generally more likely to be filtered by nasal hairs caught by facial masks, making them less likely to remain suspended in the air compared to airborne droplet nuclei. Â
Vector transmission: A mosquito, tick, or louse is an example of an arthropod that typically picks up viruses by feeding on an infected host, which can be an animal or a person, and then spreads the pathogens to a new, uninfected person. For instance, bacteria such as Shigella have the ability to stick to house fly footpads and spread in this medium.Â
Vehicle transmission: Bacterial infection from the water and food enters into the intestine through mouth, surviving the stomach’s low pH and adhering to the cell surfaces. Fomites, obtained from contact with contaminated objects attaches to the skin of host and deposit on the mucous membrane if touched.Â
Genetics
Prognostic Factors
Prognosis for a bacterial infection would depend on factors such as the type of bacteria, the site of infection, timeliness of treatment, the general health status of the patient, resistance of the bacteria to antibiotics, age and immune function, and the existence of complications. Depending on the bacteria involved, it may cause a very mild infection or result in severe acute or chronic conditions. The site of infection also influences the prognosis: skin and soft tissue infections have a better prognosis compared to deep-seated infections. Better prognosis could be due to early diagnosis with early institution of appropriate antibiotics, while delayed treatment may be associated with complications or progression to more severe diseases. Overall status of health, including comorbid conditions, could also impact recovery. Antibiotic resistance could make treatment more complicated and thus require more aggressive treatment modalities. In general, early diagnosis and appropriate antibiotic treatment, together with management strategies, usually have a good prognosis.Â
Clinical History
The signs and symptoms of bacterial infections depend on the type of bacteria responsible and the location of infection. General features of bacterial infections includeÂ
Physical Examination
Respiratory manifestations: This may include sinusitis, pneumonia, bronchitis.Â
Skin manifestations: Rashes, impetigo, folliculitisÂ
STIs: Effects rectum, genitals.Â
Ear infections: Dizziness, headaches and pain in ear due to infection in middle ear.Â
GI infections: H.pylori may infect the digestive system.Â
Meningitis: membranes of the brain may be infected.Â
Blood stream infections: By entering into the blood it causes sepsis, a serious infection of blood.Â
The symptoms experienced may vary depending on the kind of bacterial infection. For example, UTIs often cause painful micturition and frequent urges to use the bathroom. Gastrointestinal infections might lead to diarrhea, nausea, pain in abdominal and vomiting. Skin infections can result in boils, pus-filled bumps or rashes.Â
Age group
Associated comorbidity
Associated activity
Acuity of presentation
Differential Diagnoses
Laboratory Studies
Imaging Studies
Procedures
Histologic Findings
Staging
Treatment Paradigm
Treatment of bacterial infections involves a well- organized course with imaging tests, laboratory investigations, clinical assessment, and diagnosis. Streamlined treatment also comprises dedicated therapy and care support in addition to empirical antibiotic therapy. Dosage and duration of antibiotics are adjusted based on the severity of infection and individual patient factors. Monitoring and follow-up are crucial for assessment of response to therapy, control of side effects, institution of preventive measures, and consideration of antibacterial resistance. Further therapy may be necessary in some infections with complications or those that become chronic. Education of the patient is very important to enhance compliance with medication and to identify early warning signs of complications. Â
by Stage
by Modality
Chemotherapy
Radiation Therapy
Surgical Interventions
Hormone Therapy
Immunotherapy
Hyperthermia
Photodynamic Therapy
Stem Cell Transplant
Targeted Therapy
Palliative Care
modification-of-the-environment
Infection control measuresÂ
Maintaining hygiene prevents the spread of illness in households and healthcare facilities requires regular cleaning, disinfection, hand washing and sterilization.Â
Environmental modificationsÂ
To improve the quality of air indoors, it is necessary to use either HEPA filters or air purifiers and adequate ventilation. This will help in ensuring its safety for consumption after regular treatment and purification process.Â
Behavioural changesÂ
By encouraging good personal hygiene behaviours such as handwashing, ensuring a safe sex life, and handling food properly, bacterial infections can be averted. Meanwhile, vaccines targeting bacterial agents help in restricting the proliferation of diseases.Â
Patient environmentÂ
Wound care involves ensuring that there is no contamination or dirt on wounds. In order to prevent bacterial infections, wound care requires maintaining sterility and cleanliness.Â
Public health measuresÂ
The purpose of this campaign in education is to enlighten the society on cleanliness habits, immunization and prompt actions against bacterial diseases.Â
Use of antibiotics
Antibiotics or antimicrobial agents should have specific sites of action in the infecting organism but not in the host cells. There exist four major bacterial cell sites that may be directed at antibiotic action namely, cell wall, cell membrane, nucleic acid synthetic pathway, and ribosome. In the classification of antibiotics, they are grouped based on bactericidal or bacteriostatic properties, chemical structure, and target site. There are certain classes of antibiotics to which some bacteria are inherently resistant; some acquire resistance through several mechanisms. Resistant organisms survive in the presence of antibiotics and spread throughout the host. The major mechanisms of resistance include alteration of the target site, alteration in access to the target site, and production of enzymes likely to inactivate the antibiotic. Proper use of antibiotics should be done in view of the menace of antibiotic resistance.Â
use-of-phases-of-management-in-treating-bacterial-infections
There are ordered guidelines to follow in the treatment of bacterial infections. These include diagnostic and evaluation phases, an initial management phase, a targeted phase of therapy, monitoring and follow-up, prevention measures and education, long-term management, and special considerations.Â
Diagnosis and evaluation involve history taking, symptom assessment, and physical examination. Diagnostic evaluation includes laboratory tests, imaging studies, and other investigations that may establish the identity of the pathogenic bacterium and its susceptibility to antibacterial drugs. Assessment of severity characterizes the extent of infection and decides further treatment.Â
The initial management consists of initiation of broad-spectrum antibiotics based on likely pathogens and clinical guidelines, followed by initiation of antibiotic therapy with supportive care. Culture results and sensitivities can be used for adjustment of the antibiotics involved with a possible change in dosage and duration depending on the severity of the illness, response and probable side effects. Preventive measures would then include infection control, patient education, and how to manage the condition of a patient for a longer period. Other considerations in special situations include antibiotic stewardship and multidisciplinary approach in complicated cases.Â
Medication
125 - 250
mg
Orally 
every 6-8 hrs
125 - 500
mg
Capsule
Orally 
4 times a day
Note:
Used to treat infections caused by Staphylococcus aureus
consume on an empty stomach
Dose Adjustments
Renal Impairment
Data not available
Hepatic Impairment
Data not available
moderate infections:
1-2g intramuscular or intravenous every 8 to 12 hours
severe infections:
2g intravenous every 6 to 8 hours
Indicated for Anaerobic Bacterial Infection
15 mg/kg can be given intravenously but should not exceed 4 gm per day
Indicated for Anaerobic Bacterial Infection
15 mg/kg can be given intravenously but should not exceed 4 gm per day
Indicated for Anaerobic Bacterial Infection
15 mg/kg can be given intravenously but should not exceed 4 gm per day
Indicated for Anaerobic Bacterial Infection
15 mg/kg can be given intravenously but should not exceed 4 gm per day
Indicated for Neutropenia and Refractory Fungal or Bacterial Infection
Standard dose- 1 apheresis unit/day, which is approximately 300-400 ml.
The number of granulocytes per dose can vary widely, ranging from 1-8 x 1010 granulocytes/collection, depending on the donor and the mobilization regimen used.
granulocytes are usually given daily for at least 5 consecutive days, and treatment should be continued until the infection resolves or the absolute neutrophil count remains above 500/uL for at least two days.
Indicated for gram-negative infection
2.5-5 mg/kg each day intravenously or intramuscularly in 2-4 divided dose, based on infection severity
Do not exceed the dose of more than 5 mg/kg each day
50-75mg can be inhaled as normal saline through nebulizer 2-3 times daily
Indicated for gonococcal infection in the urethra of males
Take 400 mg orally twice daily for 7-10 days with food
or
Infuse 400 mg in 5% 100 ml of dextrose for 1 hour twice daily
4 to 6 mg/kg administered once a day or in divided dosages every 2-3 times a day. Life-threatening infections: dose to 7.5 mg/kg/day every 3 times a day
Administer daily dose of 400 mg intramuscularly or intravenously in 1 to 2 divided doses
Indicated for Antibacterial Agent
There is limited information available
azithromycin and benzalkonium chlorideÂ
one tablet is orally taken 1 hour before or 2 hours after the meal
The recommended maximum consumption is 0.7 mg/kg based on the individual's body weight
A lethal dose typically amounts to approximately 10 grams for an adult
Indicated for bacterial sinus infections
Take 500 mg oral tablet four times a day for 10 days
In vivo, data suggests taking 250 mg-500 mg orally after fasting overnight
4 grams daily given intramuscular or intravenous injection in two divided doses
in critical cases, may increase to 6 grams daily in three divided doses 2 grams given as intravenous infusion for loading dose; in critical cases, 4- 6 grams daily is given
sucralfate/tinidazole/povidone iodineÂ
Apply sufficient quantity of ointment topically to the affected area of skin for 3 to 4 times daily
Parenteral administration of 0.5-1 g twice a day via IV or slow IV injection over 3-5minutes
For serious infection dose is 3-4 g 3 times daily is recommended treatment of infection
IV infusion dose can be given over 10-60 minutes daily
Parenteral administration of 0.5-1 g twice a day via IV or slow IV injection over 3-5minutes. For severe infection, a dose of 3-4 g 3 times daily is recommended treatment of infection. IV infusion dose can be given over 10-60 minutes daily.
Dose Adjustments
Renal Dose Adjustments
A dose of 1 -2 g IV administration is necessary for every 48 hours if CrCl is below 10 mL/min, for every 24 hours if CrCl is between 10 and 29 mL/min, for every 16 hours if CrCl is between 30 and 49 mL/min and for every 12 hours if CrCl is between 50 and 90 mL/min respectively.
It is a broad-spectrum antibiotic that is used in the treatment of bacterial infections, which is administered in 1 g injectable solution (IM/ IV)
Dose Adjustments
No established data for dose modifications in renal or hepatic impairment patients is available
Sulfisoxazole is a sulfonamide antibiotic prescribed for treating certain bacterial infections
4000 to 8000 mg per day, divided and given in 4 – 6 doses daily
Dose Adjustments
Not Available
It is indicated for the treatment of bacterial eye infections
Application of 1 eye drop is recommended for the affected eye. It is used 3 or 4 times in a day
Administer 1g of suspension orally
A thin layer of drug to be applied on the affected area 2-3 times daily-
The bacterial ribosome is the site of action for dalfopristin, as it prevents the initial stages of protein synthesis there
Together, quinupristin/dalfopristin target the bacterial ribosome; quinupristin affects the late phase of protein synthesis, while dalfopristin concentrates on the early phase suppression
Methicillin-resistant and methicillin-sensitive staphylococci are both susceptible to the bactericidal action of synercid. Unlike beta-lactams, glycopeptides, macrolides, aminoglycosides, lincosamides, quinolones, and tetracyclines, it acts differently against bacteria
Accordingly, when Synercid and these drugs are tested using the minimum inhibitory concentration (MIC) method, there is no cross-resistance
Combination dosage:
The usual recommended dosage is 7.5 mg/kg (given over one hour time period) via IV daily 2 times for one week for skin infections and 3 times for bacterima (off-label)
Dose Adjustments
Limited data is available
The bacterial ribosome is the site of action for dalfopristin, as it prevents the initial stages of protein synthesis there
Together, quinupristin/dalfopristin target the bacterial ribosome; this drug affects the late phase of protein synthesis, while dalfopristin concentrates on the early phase suppression
Methicillin-resistant and methicillin-sensitive staphylococci are both susceptible to the bactericidal action of synercid; Unlike beta-lactams, glycopeptides, macrolides, aminoglycosides, lincosamides, quinolones, and tetracyclines, it acts differently against bacteria
Accordingly, when Synercid and these drugs are tested using the minimum inhibitory concentration (MIC) method, there is no cross-resistance
Combination dosage:
The usual recommended dosage is 7.5 mg/kg (given over one hour time period) via IV daily 2 times for one week for skin infections and 3 times for bacterima (off-label)
Dose Adjustments
Limited data is available
Investigational Drug for the treatment of bacterial infections
In vivo, data suggests taking 17mg/kg orally either as one dose or in two doses at six to eight hours duratio
The oral administration of 34 mg/kg split in either two or three doses is taken every six hours
Indicated for the treatment of bacterial infections
The usual dose is 1 g via Parenteral administration (IV or IM) four times a day for two weeks
Dose Adjustments
Limited data is available
The macrolide antibiotic drug, which is efficient against Gram-positive bacteria, is sourced from Streptomyces kitasatoensis strains
The recommended dosage for susceptible infections is 400 mg via oral administration daily twice for one week, which can be extended to 2 weeks if required
Dose Adjustments
Limited data is available
The FDA approval is pending for the drug, which is marketed in Italy under the trade name of Marespin
It is effective in the management and treatment of acute respiratory diseases and primary bacterial infections
Mild/Moderate: FDA recommends a dose of 250-500 mg given through IV or IM every 4-6hrs
Severe: FDA recommends a dose of 1 g given through IV or IM every 4-6 hrs
250 to 500mg every 6 hours
The dose can be increased as per symptoms and intensity of infection
Mild/moderate: A dose of 500mg IM given for every 4-6hrs or 500mg IV given for every 4hrs
Severe infections: A dose of 1 g IM or IV given every 4hrs
A dose of 3-4 g IV given every 4-6hrs is recommended
The maximum dose per day recommended is 24g
Age > 12 years:
125 - 250
mg
orally
every 6-8 hrs
10
days
<40 kg:
12.5 - 25
mg/day
Orally 
divided in to 4 times a day
Severe infection: 50-100 mg/kg/day orally divided in to 4 times a day
≥40 kg: 125-500 mg orally 4 times a day
Note:
Used to treat infections caused by Staphylococcus aureus
consume on an empty stomach
≤7 days:
<2kg bodyweight: 30mg/kg intravenous every 12 hours
>2 kg bodyweight: 30mg/kg intravenous every 8 hours
8 to 30 days:
<1.2kg: 30mg/kg intravenous every 12 hours
1.2kg-2kg: 30mg/kg intravenous every 8 hours
>2kg: 30mg/kg intravenous every 6 hours
1 to 18 years: 30mg/kg intravenous every 6-8 hours
Indicated for Neutropenia and Refractory Fungal or Bacterial Infection
Small children and infants- 1-2 x 109 granulocytes/kg. /day.
Based on the granulocyte concentration of the donor, volume varies, but usually, it ranges from 10-20 ml/kg.
The standard regimen for granulocyte transfusion involves daily transfusions for 5 or more consecutive days. Treatment should be continued until the infection resolves or the absolute neutrophil count remains above 500/uL for two days.
Indicated for gram-negative infection
2.5-5 mg/kg each day intravenously or intramuscularly in 2-4 divided dose, based on infection severity
Do not exceed the dose of more than 5 mg/kg each day
50-75mg can be inhaled as normal saline through nebulizer 2-3 times daily
For neonates, in the treatment of ventilator-associated pneumonia, administer 4mg/kg in each dose through inhalation
Indicated for Bacterial infections
Age >10 years
500 mg orally two times a day
Age >1 year
12.5 mg/Kg to 17.5 mg/kg orally two times a day
Age 3 months-1 year
40 mg/kg to 60 mg/kg orally two times a day
sucralfate/tinidazole/povidone iodineÂ
For 13 to 18 years old:
Apply sufficient quantity of ointment topically to the affected area of skin for 3 to 4 times daily
The usual dose for the treatment is 75 mg/kg oral administration followed by 120 – 150 mg/kg/day in divided doses 4 or 6 times a day in infants two months or older
Dose Adjustments
Not Available
It is used in the treatment of bacterial infections
The bacterial ribosome is the site of action for this drug, as it prevents the initial stages of protein synthesis there
Together, with quinupristin which target the bacterial ribosome; quinupristin affects the late phase of protein synthesis, while this drug concentrates on the early phase suppression
Methicillin-resistant and methicillin-sensitive staphylococci are both susceptible to the bactericidal action of synercid. Unlike beta-lactams, glycopeptides, macrolides, aminoglycosides, lincosamides, quinolones, and tetracyclines, it acts differently against bacteria
Accordingly, when Synercid and these drugs are tested using the minimum inhibitory concentration (MIC) method, there is no cross-resistance
Safety and efficacy are not seen in pediatrics less than 16
Combination dosage:
The usual recommended dosage is 7.5 mg/kg (given over one hour time period) via IV daily 2 times for one week for skin infections
It is used in the treatment of bacterial infections
The bacterial ribosome is the site of action for dalfopristin, as it prevents the initial stages of protein synthesis there
Together, with dalfopristin which target the bacterial ribosome; this drug affects the late phase of protein synthesis, while dalfopristin concentrates on the early phase suppression
Methicillin-resistant and methicillin-sensitive staphylococci are both susceptible to the bactericidal action of synercid; Unlike beta-lactams, glycopeptides, macrolides, aminoglycosides, lincosamides, quinolones, and tetracyclines, it acts differently against bacteria
Accordingly, when Synercid and these drugs are tested using the minimum inhibitory concentration (MIC) method, there is no cross-resistance
Safety and efficacy are not seen in pediatrics less than 16
Combination dosage:
The usual recommended dosage is 7.5 mg/kg (given over one hour time period) via IV daily 2 times for one week for skin infections
Dose Adjustments
Limited data is available
Indicated for the treatment of bacterial infections
The usual dose is 25 mg/kg via Parenteral administration (IV or IM) four times a day for two weeks in children between 2 to 18 years of age
Safety and efficacy are not seen in pediatrics below two years of age
For premature and neonates, a dose of 25 mg per kg per day IV or IM is recommended
For infants and children, the weight bearing less than 40 kg for mild/moderate infections a dose of 12.5 mg per kg per day given IV or IM for every 6hrs
recommended and for severe 100 mg per kg per day IV or IM given for every 4-6hrs
For infants and children, the weight bearing more than 40 kg for mild/moderate infections a dose of 250-500 mg per day given IV or IM for every 4-6hrs recommended and for severe 1 g per day IV or IM given for every 4-6hrs is recommended
Mild/Moderate: For neonates, a dose of 10 mg per kg IM given 2 times a day is recommended. For infants and children who are weighing < 40 kg recommends a dose of 25 mg per kg IM 2 times a day
For infants and children who are weighing > 40 kg recommends a dose of 500 mg IM every 4-6hrs hours a day
Severe: A dose of 1 g IM given every 4hrs a day
For less than 1 week a dose of 75 mg per kg is given every 12hrs
For 1 week to less than 1 month a dose of 75 mg per kg is given every 6 to 8hrs
For 1 month and less than12 years: 50-75 mg per kg is given every 4hrs
For 12 years old the usual adult dose is followed
Future Trends
References
Bacterial infections have a huge impact on public health. These diseases can result either from bacterium itself or from the host’s reaction to its presence. Infections may then result at any body site and be water-borne, food-borne, vector-borne, and air-borne. The common modes of transmission for bacteria are direct contact, vectors, contaminated vehicles, airborne, and droplets. Such morbidity and mortality were strictly observed, which includes water treatment, immunization of both human beings and animals, practicing safe sex, and good personal hygiene. The increased resistance by bacteria to some antibiotics further supports the use of antibiotics with extreme care and caution.Â
The development of bacterial infections and diseases is influenced by several factors, including pathogenicity, virulence and infectivity. Infectivity refers to the organism’s ability to spread to susceptible individuals, pathogenicity assesses its potential to cause disease, and virulence indicates the severity of the disease it can produce. Host factors, such as nutritional status, age, duration of exposure, and genetic predisposition may also impact the disease progression. Additionally, environmental factors like air pollution and chemical exposures can weaken the body’s defences against bacterial infections.Â
The external environment usually provides the site for contact between the bacterial agent and the host and where infections are ultimately obtained. There are various ways in which the bacteria are able to be transmitted to human beings, including water, food, air, and even living vectors. The transmission of bacteria is affected by both macro and microenvironments. For example, there are specific settings like jails and hospitals that may be hosting some unique types of bacteria. Some bacteria may also be relatively uncommon or even totally absent in other different geographical regions.Â
Human reservoirs: Bacterial infections are often transmitted through humans because they themselves act as a vector by harboring the disease but not showing any symptoms. An example of a passive carrier is Neisseria meningitidis, which harbors the bacterium in its respiratory tract. During the incubating period, the virus may be transmitted due to incubator carriers. The asymptomatic individuals also transmit sexually transmitted diseases. During the time when the individual is recovering, the convalescent carriers transmit the organism. Active carriers carry the organism in their body indefinitely after recovering from the illness. The Salmonella, especially Salmonella Typhi, may form a chronic carrier status without symptoms in the individual. From thereon, the carriers may transmit the pathogen to their contacts, continuously. Mary Mallon is a cook in New York City who was responsible for many typhoid disease outbreaks.Â
Animal reservoirs: Some zoonotic diseases that can enter and infect human beings and cause diseases through direct contact, ingestion, inhalation, or bites from animal reservoirs include Bacillus anthracis anthrax, Lyme disease, Francisella tularensis tularemia, and Salmonella diarrhea caused by Borrelia. Since zoonotic overflow occurs as a cycle of transmission between the tick hosts and animal hosts such as deer and mice. This overflow allows for infected ticks to overflow from the natural cycle of infection into humans and hence, is an important event in zoonotic diseases. In New England, it has been found that culling the deer infected with this disease on an island will almost eliminate human infection and also significantly reduce the ticks that are infected.Â
Arthropod reservoirs: Arthropods are the reservoirs for diseases. They transmit infection by the vector. It includes the flies, fleas, and lice that carry on the diseases. The bacterium Borrelia infects ticks, and after the blood meal from an infected animal, they introduce it into human beings. Other diseases that are caused by arthropod association include murine, Rocky Mountain spotted fever, scrub, bubonic plague, and typhus epidemica. These are transmitted by mites, mice, infected deer, or ticks.Â
Non-living reservoirs: Finally, air can get contaminated by some pathogenic bacteria, like tuberculosis that are transported by air currents. Soil acts as a reservoir for spore-forming bacteria like Clostridium, that causes tetanus, botulism, and gas gangrene. Poorly handled food, including milk, will act as a reservoir for several pathogenic organisms. Botulism can result from food contamination by feces, infected animals, or Botulinum spores. Food handlers harbor bacteria on their hands, and stringent regulations are followed to protect public health. Uncooked foods such as alfalfa and raw seed sprouts may also serve as the reservoir for bacterial infections. Water may also serve as a reservoir of infection following contamination by soil microbes or animal or human faeces or raw sewage. Inanimate objects such as doorknobs and toilet seats and utensils transmit infection indirectly. Many respiratory infections are not directly transmitted by aerosol, but by respiratory secretions being deposited on surfaces and hands and having secondary transmission by hand-to-mouth contact.Â
Modes of transmissionÂ
Bacterial infections can be transmitted through five primary modes namely airborne, contact, droplet, vehicular and vectors which includes contaminated food, fomites and water.Â
Contact transmission: Transmission through contact involve es mucous membrane-to-mucous membrane contact or direct skin-to-skin contact, as well as fecal- oral transmission of intestinal bacteria. Additionally, bacterial infections such as syphilis can be spread through transfusions of contaminated blood products.Â
Airborne transmission: Certain bacteria are carried by air currents in droplet nuclei, allowing them to travel significant distances from their source. For instance, tuberculosis, Legionella, and Q fever can spread over long distances. In some cases, animals with Q fever have been known to transmit the infection to other animals up to 10 miles away.Â
Droplet transmission: When an infection is spread through droplets larger than 5µm in diameter, it is not classified as airborne because such droplets typically do not travel more than 1m through air. These larger droplets are generally more likely to be filtered by nasal hairs caught by facial masks, making them less likely to remain suspended in the air compared to airborne droplet nuclei. Â
Vector transmission: A mosquito, tick, or louse is an example of an arthropod that typically picks up viruses by feeding on an infected host, which can be an animal or a person, and then spreads the pathogens to a new, uninfected person. For instance, bacteria such as Shigella have the ability to stick to house fly footpads and spread in this medium.Â
Vehicle transmission: Bacterial infection from the water and food enters into the intestine through mouth, surviving the stomach’s low pH and adhering to the cell surfaces. Fomites, obtained from contact with contaminated objects attaches to the skin of host and deposit on the mucous membrane if touched.Â
Prognosis for a bacterial infection would depend on factors such as the type of bacteria, the site of infection, timeliness of treatment, the general health status of the patient, resistance of the bacteria to antibiotics, age and immune function, and the existence of complications. Depending on the bacteria involved, it may cause a very mild infection or result in severe acute or chronic conditions. The site of infection also influences the prognosis: skin and soft tissue infections have a better prognosis compared to deep-seated infections. Better prognosis could be due to early diagnosis with early institution of appropriate antibiotics, while delayed treatment may be associated with complications or progression to more severe diseases. Overall status of health, including comorbid conditions, could also impact recovery. Antibiotic resistance could make treatment more complicated and thus require more aggressive treatment modalities. In general, early diagnosis and appropriate antibiotic treatment, together with management strategies, usually have a good prognosis.Â
The signs and symptoms of bacterial infections depend on the type of bacteria responsible and the location of infection. General features of bacterial infections includeÂ
Respiratory manifestations: This may include sinusitis, pneumonia, bronchitis.Â
Skin manifestations: Rashes, impetigo, folliculitisÂ
STIs: Effects rectum, genitals.Â
Ear infections: Dizziness, headaches and pain in ear due to infection in middle ear.Â
GI infections: H.pylori may infect the digestive system.Â
Meningitis: membranes of the brain may be infected.Â
Blood stream infections: By entering into the blood it causes sepsis, a serious infection of blood.Â
The symptoms experienced may vary depending on the kind of bacterial infection. For example, UTIs often cause painful micturition and frequent urges to use the bathroom. Gastrointestinal infections might lead to diarrhea, nausea, pain in abdominal and vomiting. Skin infections can result in boils, pus-filled bumps or rashes.Â
Treatment of bacterial infections involves a well- organized course with imaging tests, laboratory investigations, clinical assessment, and diagnosis. Streamlined treatment also comprises dedicated therapy and care support in addition to empirical antibiotic therapy. Dosage and duration of antibiotics are adjusted based on the severity of infection and individual patient factors. Monitoring and follow-up are crucial for assessment of response to therapy, control of side effects, institution of preventive measures, and consideration of antibacterial resistance. Further therapy may be necessary in some infections with complications or those that become chronic. Education of the patient is very important to enhance compliance with medication and to identify early warning signs of complications. Â
Infectious Disease
Infection control measuresÂ
Maintaining hygiene prevents the spread of illness in households and healthcare facilities requires regular cleaning, disinfection, hand washing and sterilization.Â
Environmental modificationsÂ
To improve the quality of air indoors, it is necessary to use either HEPA filters or air purifiers and adequate ventilation. This will help in ensuring its safety for consumption after regular treatment and purification process.Â
Behavioural changesÂ
By encouraging good personal hygiene behaviours such as handwashing, ensuring a safe sex life, and handling food properly, bacterial infections can be averted. Meanwhile, vaccines targeting bacterial agents help in restricting the proliferation of diseases.Â
Patient environmentÂ
Wound care involves ensuring that there is no contamination or dirt on wounds. In order to prevent bacterial infections, wound care requires maintaining sterility and cleanliness.Â
Public health measuresÂ
The purpose of this campaign in education is to enlighten the society on cleanliness habits, immunization and prompt actions against bacterial diseases.Â
Infectious Disease
Antibiotics or antimicrobial agents should have specific sites of action in the infecting organism but not in the host cells. There exist four major bacterial cell sites that may be directed at antibiotic action namely, cell wall, cell membrane, nucleic acid synthetic pathway, and ribosome. In the classification of antibiotics, they are grouped based on bactericidal or bacteriostatic properties, chemical structure, and target site. There are certain classes of antibiotics to which some bacteria are inherently resistant; some acquire resistance through several mechanisms. Resistant organisms survive in the presence of antibiotics and spread throughout the host. The major mechanisms of resistance include alteration of the target site, alteration in access to the target site, and production of enzymes likely to inactivate the antibiotic. Proper use of antibiotics should be done in view of the menace of antibiotic resistance.Â
Infectious Disease
There are ordered guidelines to follow in the treatment of bacterial infections. These include diagnostic and evaluation phases, an initial management phase, a targeted phase of therapy, monitoring and follow-up, prevention measures and education, long-term management, and special considerations.Â
Diagnosis and evaluation involve history taking, symptom assessment, and physical examination. Diagnostic evaluation includes laboratory tests, imaging studies, and other investigations that may establish the identity of the pathogenic bacterium and its susceptibility to antibacterial drugs. Assessment of severity characterizes the extent of infection and decides further treatment.Â
The initial management consists of initiation of broad-spectrum antibiotics based on likely pathogens and clinical guidelines, followed by initiation of antibiotic therapy with supportive care. Culture results and sensitivities can be used for adjustment of the antibiotics involved with a possible change in dosage and duration depending on the severity of the illness, response and probable side effects. Preventive measures would then include infection control, patient education, and how to manage the condition of a patient for a longer period. Other considerations in special situations include antibiotic stewardship and multidisciplinary approach in complicated cases.Â
Bacterial infections have a huge impact on public health. These diseases can result either from bacterium itself or from the host’s reaction to its presence. Infections may then result at any body site and be water-borne, food-borne, vector-borne, and air-borne. The common modes of transmission for bacteria are direct contact, vectors, contaminated vehicles, airborne, and droplets. Such morbidity and mortality were strictly observed, which includes water treatment, immunization of both human beings and animals, practicing safe sex, and good personal hygiene. The increased resistance by bacteria to some antibiotics further supports the use of antibiotics with extreme care and caution.Â
The development of bacterial infections and diseases is influenced by several factors, including pathogenicity, virulence and infectivity. Infectivity refers to the organism’s ability to spread to susceptible individuals, pathogenicity assesses its potential to cause disease, and virulence indicates the severity of the disease it can produce. Host factors, such as nutritional status, age, duration of exposure, and genetic predisposition may also impact the disease progression. Additionally, environmental factors like air pollution and chemical exposures can weaken the body’s defences against bacterial infections.Â
The external environment usually provides the site for contact between the bacterial agent and the host and where infections are ultimately obtained. There are various ways in which the bacteria are able to be transmitted to human beings, including water, food, air, and even living vectors. The transmission of bacteria is affected by both macro and microenvironments. For example, there are specific settings like jails and hospitals that may be hosting some unique types of bacteria. Some bacteria may also be relatively uncommon or even totally absent in other different geographical regions.Â
Human reservoirs: Bacterial infections are often transmitted through humans because they themselves act as a vector by harboring the disease but not showing any symptoms. An example of a passive carrier is Neisseria meningitidis, which harbors the bacterium in its respiratory tract. During the incubating period, the virus may be transmitted due to incubator carriers. The asymptomatic individuals also transmit sexually transmitted diseases. During the time when the individual is recovering, the convalescent carriers transmit the organism. Active carriers carry the organism in their body indefinitely after recovering from the illness. The Salmonella, especially Salmonella Typhi, may form a chronic carrier status without symptoms in the individual. From thereon, the carriers may transmit the pathogen to their contacts, continuously. Mary Mallon is a cook in New York City who was responsible for many typhoid disease outbreaks.Â
Animal reservoirs: Some zoonotic diseases that can enter and infect human beings and cause diseases through direct contact, ingestion, inhalation, or bites from animal reservoirs include Bacillus anthracis anthrax, Lyme disease, Francisella tularensis tularemia, and Salmonella diarrhea caused by Borrelia. Since zoonotic overflow occurs as a cycle of transmission between the tick hosts and animal hosts such as deer and mice. This overflow allows for infected ticks to overflow from the natural cycle of infection into humans and hence, is an important event in zoonotic diseases. In New England, it has been found that culling the deer infected with this disease on an island will almost eliminate human infection and also significantly reduce the ticks that are infected.Â
Arthropod reservoirs: Arthropods are the reservoirs for diseases. They transmit infection by the vector. It includes the flies, fleas, and lice that carry on the diseases. The bacterium Borrelia infects ticks, and after the blood meal from an infected animal, they introduce it into human beings. Other diseases that are caused by arthropod association include murine, Rocky Mountain spotted fever, scrub, bubonic plague, and typhus epidemica. These are transmitted by mites, mice, infected deer, or ticks.Â
Non-living reservoirs: Finally, air can get contaminated by some pathogenic bacteria, like tuberculosis that are transported by air currents. Soil acts as a reservoir for spore-forming bacteria like Clostridium, that causes tetanus, botulism, and gas gangrene. Poorly handled food, including milk, will act as a reservoir for several pathogenic organisms. Botulism can result from food contamination by feces, infected animals, or Botulinum spores. Food handlers harbor bacteria on their hands, and stringent regulations are followed to protect public health. Uncooked foods such as alfalfa and raw seed sprouts may also serve as the reservoir for bacterial infections. Water may also serve as a reservoir of infection following contamination by soil microbes or animal or human faeces or raw sewage. Inanimate objects such as doorknobs and toilet seats and utensils transmit infection indirectly. Many respiratory infections are not directly transmitted by aerosol, but by respiratory secretions being deposited on surfaces and hands and having secondary transmission by hand-to-mouth contact.Â
Modes of transmissionÂ
Bacterial infections can be transmitted through five primary modes namely airborne, contact, droplet, vehicular and vectors which includes contaminated food, fomites and water.Â
Contact transmission: Transmission through contact involve es mucous membrane-to-mucous membrane contact or direct skin-to-skin contact, as well as fecal- oral transmission of intestinal bacteria. Additionally, bacterial infections such as syphilis can be spread through transfusions of contaminated blood products.Â
Airborne transmission: Certain bacteria are carried by air currents in droplet nuclei, allowing them to travel significant distances from their source. For instance, tuberculosis, Legionella, and Q fever can spread over long distances. In some cases, animals with Q fever have been known to transmit the infection to other animals up to 10 miles away.Â
Droplet transmission: When an infection is spread through droplets larger than 5µm in diameter, it is not classified as airborne because such droplets typically do not travel more than 1m through air. These larger droplets are generally more likely to be filtered by nasal hairs caught by facial masks, making them less likely to remain suspended in the air compared to airborne droplet nuclei. Â
Vector transmission: A mosquito, tick, or louse is an example of an arthropod that typically picks up viruses by feeding on an infected host, which can be an animal or a person, and then spreads the pathogens to a new, uninfected person. For instance, bacteria such as Shigella have the ability to stick to house fly footpads and spread in this medium.Â
Vehicle transmission: Bacterial infection from the water and food enters into the intestine through mouth, surviving the stomach’s low pH and adhering to the cell surfaces. Fomites, obtained from contact with contaminated objects attaches to the skin of host and deposit on the mucous membrane if touched.Â
Prognosis for a bacterial infection would depend on factors such as the type of bacteria, the site of infection, timeliness of treatment, the general health status of the patient, resistance of the bacteria to antibiotics, age and immune function, and the existence of complications. Depending on the bacteria involved, it may cause a very mild infection or result in severe acute or chronic conditions. The site of infection also influences the prognosis: skin and soft tissue infections have a better prognosis compared to deep-seated infections. Better prognosis could be due to early diagnosis with early institution of appropriate antibiotics, while delayed treatment may be associated with complications or progression to more severe diseases. Overall status of health, including comorbid conditions, could also impact recovery. Antibiotic resistance could make treatment more complicated and thus require more aggressive treatment modalities. In general, early diagnosis and appropriate antibiotic treatment, together with management strategies, usually have a good prognosis.Â
The signs and symptoms of bacterial infections depend on the type of bacteria responsible and the location of infection. General features of bacterial infections includeÂ
Respiratory manifestations: This may include sinusitis, pneumonia, bronchitis.Â
Skin manifestations: Rashes, impetigo, folliculitisÂ
STIs: Effects rectum, genitals.Â
Ear infections: Dizziness, headaches and pain in ear due to infection in middle ear.Â
GI infections: H.pylori may infect the digestive system.Â
Meningitis: membranes of the brain may be infected.Â
Blood stream infections: By entering into the blood it causes sepsis, a serious infection of blood.Â
The symptoms experienced may vary depending on the kind of bacterial infection. For example, UTIs often cause painful micturition and frequent urges to use the bathroom. Gastrointestinal infections might lead to diarrhea, nausea, pain in abdominal and vomiting. Skin infections can result in boils, pus-filled bumps or rashes.Â
Treatment of bacterial infections involves a well- organized course with imaging tests, laboratory investigations, clinical assessment, and diagnosis. Streamlined treatment also comprises dedicated therapy and care support in addition to empirical antibiotic therapy. Dosage and duration of antibiotics are adjusted based on the severity of infection and individual patient factors. Monitoring and follow-up are crucial for assessment of response to therapy, control of side effects, institution of preventive measures, and consideration of antibacterial resistance. Further therapy may be necessary in some infections with complications or those that become chronic. Education of the patient is very important to enhance compliance with medication and to identify early warning signs of complications. Â
Infectious Disease
Infection control measuresÂ
Maintaining hygiene prevents the spread of illness in households and healthcare facilities requires regular cleaning, disinfection, hand washing and sterilization.Â
Environmental modificationsÂ
To improve the quality of air indoors, it is necessary to use either HEPA filters or air purifiers and adequate ventilation. This will help in ensuring its safety for consumption after regular treatment and purification process.Â
Behavioural changesÂ
By encouraging good personal hygiene behaviours such as handwashing, ensuring a safe sex life, and handling food properly, bacterial infections can be averted. Meanwhile, vaccines targeting bacterial agents help in restricting the proliferation of diseases.Â
Patient environmentÂ
Wound care involves ensuring that there is no contamination or dirt on wounds. In order to prevent bacterial infections, wound care requires maintaining sterility and cleanliness.Â
Public health measuresÂ
The purpose of this campaign in education is to enlighten the society on cleanliness habits, immunization and prompt actions against bacterial diseases.Â
Infectious Disease
Antibiotics or antimicrobial agents should have specific sites of action in the infecting organism but not in the host cells. There exist four major bacterial cell sites that may be directed at antibiotic action namely, cell wall, cell membrane, nucleic acid synthetic pathway, and ribosome. In the classification of antibiotics, they are grouped based on bactericidal or bacteriostatic properties, chemical structure, and target site. There are certain classes of antibiotics to which some bacteria are inherently resistant; some acquire resistance through several mechanisms. Resistant organisms survive in the presence of antibiotics and spread throughout the host. The major mechanisms of resistance include alteration of the target site, alteration in access to the target site, and production of enzymes likely to inactivate the antibiotic. Proper use of antibiotics should be done in view of the menace of antibiotic resistance.Â
Infectious Disease
There are ordered guidelines to follow in the treatment of bacterial infections. These include diagnostic and evaluation phases, an initial management phase, a targeted phase of therapy, monitoring and follow-up, prevention measures and education, long-term management, and special considerations.Â
Diagnosis and evaluation involve history taking, symptom assessment, and physical examination. Diagnostic evaluation includes laboratory tests, imaging studies, and other investigations that may establish the identity of the pathogenic bacterium and its susceptibility to antibacterial drugs. Assessment of severity characterizes the extent of infection and decides further treatment.Â
The initial management consists of initiation of broad-spectrum antibiotics based on likely pathogens and clinical guidelines, followed by initiation of antibiotic therapy with supportive care. Culture results and sensitivities can be used for adjustment of the antibiotics involved with a possible change in dosage and duration depending on the severity of the illness, response and probable side effects. Preventive measures would then include infection control, patient education, and how to manage the condition of a patient for a longer period. Other considerations in special situations include antibiotic stewardship and multidisciplinary approach in complicated cases.Â
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