C.pseudodiphtheriticum has been linked to breathing infections like bronchitis and pneumonia. Although not often considered a major respiratory pathogen. A study at York Hospital found 17 patients with C. pseudodiphtheriticum respiratory infections between October 1990 and April 1993. About 12 cases involved bronchitis, while 5 were pneumonia. Interestingly, patients with other health issues like diabetes, heart failure, or cancer were commonly affected. Symptoms started suddenly for most, but almost two-thirds had no fever.

In total, C. pseudodiphtheriticum was found in 47 episodes, with 12% assumed to be colonization and 78% infection. Notably, 51% of infections happened in the hospital. Older age and being male were statistically more likely for infection versus colonization. 

Comorbidities like dyslipidemia, high blood pressure, invasive treatments, and chronic lung conditions were prevalent among those infected. But none significantly raised risks over colonization. 14% of infected individuals died. Respiratory samples yielded most isolates, susceptible to amoxicillin/clavulanate and vancomycin. However, resistance was high for clindamycin (77%) and erythromycin (48%). 

C. pseudodiphtheriticum is a type of pathogenic bacteria. It belongs to the group Actinobacteria and the Corynebacteriaceae This bacterium is gram-positive, which it has a certain cell wall structure.

C.pseudodiphtheriticum is a small bacterium. Its length is between 0.5 and 2.0 micrometers. Its width is between 0.3 and 0.5 micrometers. It cannot move and it is non motile. It does not have spores.

The Corynebacterium bacterium has an uncommon visual quality. It tends to appear thick or enlarged at one or both ends, which catches the eye. This distinct look links to granules within the organism’s makeup. These metachromatic granules contribute to the varying appearance noticed under a microscope. 

Corynebacterium pseudodiphtheriticum doesn’t express many different kinds of antigens. However, it is closely connected to other species like C. diphtheriae and C. ulcerans in terms of evolution. On its surface, C. pseudodiphtheriticum has lipoteichoic acid, peptidoglycan, and pili as antigens. Still, we need more research to fully understand the diversity of its antigens. 

The Corynebacterium pseudodiphtheriticum type strain ATCC 107001 was first found in a human throat sample with diphtheria bacteria. This strain is significant because scientists have sequenced its whole genome. So, it is useful for quality testing. Some other collection numbers linked to this strain include DSM 44287, CCUG 27539, NBRC 15362, NCTC 11136, and CM 11665. 

C.pseudodiphtheriticum often lives in the nose and throat areas and on the skin without causing diseases. However, certain types could cause breathing issues. They might bring on swelling or pus-filled bumps in affected body parts.

Transmission happens via direct contact with sick people or their fluids like spit, mucus, or phlegm. Inhaling cough or sneeze droplets with bacteria also risks infection. Individuals with weak immunity or health issues are more prone to C. pseudodiphtheriticum infections. 

The bacterium survives on surfaces, enabling potential spread. The respiratory tract is the main infection site, where Corynebacterium pseudodiphtheriticum may cause sore throat, tonsil inflammation, or middle ear infection. 

Our body has many ways to fight against C. pseudodiphtheriticum infection. It releases antimicrobial peptides like cathelicidins. It also generates reactive oxygen species such as superoxide and hydrogen peroxide. Additionally, it produces nitric oxide and cytokines like interferons and tumor necrosis factor-alpha. These defenses work together to create an unfriendly environment for the bacteria. 

The human body activates immune signaling molecules, which detect bacterial antigens from releasing T cells and B cells for the production of antibodies and cytotoxic T cells, these target and destroy C. pseudodiphtheriticum. The host’s immune system also forms phagolysosomes with digestive enzymes. It uses autophagy to break down cellular components and serves for programmed virulent cell death (apoptosis) by breaking down the extracellular matrix. 

The complement system also helps the immune response. It interacts with antibodies and other molecules. This interaction leads to opsonization, where the bacteria is coated for phagocytosis. It also causes membrane lysis and generates chemotactic signals. These signals attract immune cells to the site of infection. 

Corynebacterium pseudodiphtheriticum can cause lung infections. These include pneumonia, bronchitis, trachea swelling, and sore throat. C. pseudodiphtheriticum often stays in the throat and skin. Several strains make these illnesses worse. These strains can cause inflamed areas or pus-filled lumps in the infection sites. 

People with C. pseudodiphtheriticum infections have breathing problems. Their throat may hurt and feel scratchy. They might also get a mild fever, cough, and shortness of breath from the lung issues.  

Chest pain and wheezing are common symptoms. Additionally, nasal stuffiness, earaches, and swollen neck glands occur. In summary, it causes many uncomfortable respiratory symptoms throughout the head and chest areas. 

Finding infections from C. pseudodiphtheriticum usually involves looking for the bacteria in samples. Samples can be sputum, throat swabs, or wound cultures. Biochemical tests help identify the bacteria. C. pseudodiphtheriticum tests positive for catalase, which it has a certain enzyme activity. It does not ferment key carbohydrates or break down urea, which helps distinguish it from other bacteria. 

Another helpful test is nitrate reduction. The bacteria can reduce nitrates. Tests like gram staining, electron microscopy, and ELISAs (enzyme-linked immunosorbent assays) can also identify C. pseudodiphtheriticum infections.  

Confirming the identification can be done through other techniques. These include PCR (polymerase chain reaction). Another method is biotyping and toxigenicity testing. This classifies Corynebacterium pseudodiphtheriticum into different groups. The grouping depends on biochemical traits and antigenic properties. 

• Avoiding infected persons or their saliva, mucus, or sputum. This prevents spread through droplets or aerosols reducing infection risk. 

• Washing hands often, covering with the elbow while coughing or sneezing, and sanitizing surfaces destroy pathogens on objects. These stop bacteria from transmission between people and the environment. 

• It’s crucial to consult a doctor right away if sudden lung infections occur. Early diagnosis helps start the right antibiotic treatment quickly. Common antibiotics used for C. pseudodiphtheriticum infections include amoxicillin/clavulanate and vancomycin. 

Corynebacterium pseudodiphtheriticum: a respiratory tract pathogen in adults – PubMed (nih.gov) 

Corynebacterium pseudodiphtheriticum – an overview | ScienceDirect Topics