Cellulosimicrobium causes disease in humans. These organisms reside in the dirt, water, and plant debris. Though Cellulosimicrobium lives around us, getting an infection from this bacterium is uncommon and challenging to treat. 

Some peculiar cases illustrate their rarity. An 82 year old woman with an aortic valve replacement developed infective endocarditis from C. cellulans. Despite receiving antibiotics, she died 35 days after hospitalization & treatment. In another case, a patient without immune issues got bacteremia, likely from prosthetic valve endocarditis, caused by C. funkei. 

Cellulosimicrobium commonly infects people through catheters inserted into veins. Interestingly, researchers are exploring possible ways of certain Cellulosimicrobium strains could help clean up areas polluted by heavy metals in soil. They’ve identified bacteria closely matching C. funkei that may thrive under those conditions. 

Cellulosimicrobium funkei is gram-positive bacteria, belongs to the Promicromonosporaceae family of organisms. Under a microscope, its structure is seen as rod shaped bacillus cells. These cells measure 1.0 micrometers wide and 2 micrometers long. Their elongated form appears either straight or curved. 

The funkei‘s cellular structure is a thick cell wall of peptidoglycan, causes it to stain positive. Unlike negative bacteria, it is not having an outer membrane. The cytoplasmic membrane surrounds cell parts like ribosomes, nucleoids. C. funkei have flagella for movement and pili for attachment and interaction with environment and hosts. 

Research has not studied with the specific antigens of C. funkei. But an examination of C. cellulans, discovered 49 marker genes linked to human infections. These included the Fic and VbhA toxin-antitoxin systems. Since C. funkei and C. cellulans share genetic similarities, parallels exist regarding these findings in C. funkei. 

The type strain for Cellulosimicrobium funkei carries designations C8821 and W6122. Further research is needed to comprehensively characterize antigens and virulent genes in C. funkei, an area still requiring exploration and deeper understanding. 

Cellulosimicrobium funkei is an opportunistic pathogen affects those with poor health conditions, or foreign objects like central venous catheters. Pathology mechanisms are not studied well, but they involve sticking to body tissues, evading the immune system and tissues. 

This bacterium spreads from within the person’s microflora (endogenous) or from the environment or exogenous. It commonly lives in places like soil, water, and organic matter. Transmission between people in hospitals may occur via contaminated medical equipment or, rarely, person to person contact. 

A severe condition linked to Cellulosimicrobium funkei is Infectious Endocarditis, often in patients with artificial heart valves. This pathogen attaches to damaged valves, causing inflammation and tissue damage. Another issue is Central Venous Catheter-Related Bacteremia, where the bacterium enters the blood, leading to widespread infection. It results in symptoms like fever, heart failure, and even death. 

Cellulosimicrobium funkei intrudes organs by triggering the body’s innate immune response. Macrophages and neutrophils quickly mobilize. These cells engulf the Cellulosimicrobium by phagocytosis process. This initial defense safeguards health by destroying the invader swiftly. Complement proteins join the defense, stirring up inflammation and coating the bacterium, making it easier for phagocytes to eliminate. 

The adaptive immune system springs into battle against C. funkei. B cells manufacture antibodies specifically targeting the bacterial antigens. These antibodies neutralize the bacterium and assist phagocytes in devouring it. T cells, including the cytotoxic and helper varieties, recognize infected cells. They coordinate and direct immune responses. Mucous membranes of gastrointestinal and respiratory tracts act as resistance barriers, obstructing bacterial entry. Inflammation signals immune cells to swarm the infection site. 

When C. funkei is encountered, antigen presenting cells process and display its antigens to T cells. It kickstarts a precise, coordinated immune reaction against the bacterium. 

Cellulosimicrobium funkei mostly causes a severe heart infection, prosthetic infective endocarditis. This infection impacts the heart’s valves or nearby tissues after heart surgery or device implants. It’s dangerous, leading to fever, heart failure, septic shock, and sometimes death. Prosthetic infective endocarditis caused by C. funkei has a poor outlook, making it very serious. 

Apart from prosthetic infective endocarditis, Cellulosimicrobium funkei can also cause other infections. These include bloodstream infections, eye infections, soft tissue infections, meningitis, joint infections, and infections related to prosthetic joints. 

Phenotypic Tests: C. funkei has a rod-like shape. It can move around and show motility. This species grows well on Trypticase Soy Yeast Extract Medium or DSMZ Medium 92 at moderate temperatures. Some tests can tell C. funkei apart from close relatives like C. cellulans and C. terreum. These tests check if it moves, ferments raffinose, uses glycogen, grows on D-xylose or methyl-α-D-glucopyranoside, and survives at 35°C. 

Laboratory Findings: A patient with C. cellulans infective endocarditis had the usual blood cell count. Their creatinine level measured 2.14 mg/dL, indicating kidney issues. The inflammation marker C-reactive protein was elevated at 13 mg/dL. Hyperglycemia presented severely at 628 mg/dL. A chest X-ray showed bilateral pleural effusion and interstitial pulmonary edema. 

Handwashing frequently with water and soap is crucial, for healthcare staff and people near sick individuals. 

Proper isolation of infected patients prevents the bacterium from spreading to others at risk. It is vital in medical facilities to prevent transmission within the premises. 

Clean and disinfect surfaces and medical equipment to reduce contamination risks. Regular cleaning remains essential in healthcare settings as well as other locations. 

Consider removing catheters or prosthetic valves for better treatment outcomes. The valve surgery like replacement or repair help in manage complications. 

Educate patients and families on maintaining hygiene, following prescribed treatments, and recognizing infection signs. 

Cellulosimicrobium funkei: First Report of Infection in a Non-immunocompromised Patient and Useful Phenotypic Tests – PMC (nih.gov) 

Infections due to Cellulosimicrobium species: case report and literature review | BMC Infectious Diseases |(biomedcentral.com)