Enterobacter aerogenes

Enterobacter sp. Enterobacter sp. • Species: • Enterobacter aerogenes • Enterobacter agglomerans • Enterobacter cloacae – causes UTI, enterotoxigenic • Often found in the normal intestinal flora, soil and water • Differentiated from other enterobacteriaceae based on biochemical characteristics • Causes nosocomial infections esp. of urinary tract, surgical wounds, bacteremia and septicemia • Produces beta-lactamase  inactivates penicillins and 1st-gen. cephalosporins Enterobacter

– NF of GI tract – TSI, LIA, and urea give variable results depending upon species – Citrate + – Clinical significance • Nosocomial infections • Bacteremia in burn patients • Enterobacter aerogenus • Capsulated • Free living in the intestine • Cause UTI and sepsis. As part of the Enterobacteriaceae family, Enterobacter aerogenes is related to E. coli and salmonella. In terms of size, E. aerogenes is smaller than many of its microbial cousins, but its occurrence in hospitals and resistance to antibiotics have made it of particular importance. As E. aerogenes continues to evolve new strains, it will continue to pose challenges to the biomedical community. Bacteriology E. aerogenes is a rod-shaped bacteria, or a "bacillus" in scientific lingo. As a facultative anaerobe, it thrives in environments with little or no oxygen, such as soil, sewage and feces. Illnesses E. aerogenes causes a wide range of illnesses, depending on which part of the body it invades. Common illnesses include bacteremia, osteomyelitis, pneumonia and septicemia. However, E. aerogenes also causes infections in the gastrointestinal tract, the respiratory tract, the urinary tract and skin. Risk Factors E. aerogenes is an opportunistic pathogen. This means that it infects a host that has already been weakened. E. aerogenes is also a nosocomial bacteria, which means that it commonly resides in hospitals. Consequently, its risk factors include hospital stays that last 2 weeks or longer, invasive surgery, intensive care visits and use of antibiotics. Predilections Like other Enterobacter bacteria, E. aerogenes has no predilection for race. However, it does occur more frequently among newborns, toddlers and the elderly, particularly among males. Treament E. aerogenes is resistant to most antibiotics, including chloramphenicol, quinolones and tetracycline. As a result, the use of "old" drugs--- that is, drugs that were commonly prescribed in past decades---is growing in popularity. Another popular treatment is using a combination of drugs such as imipenem and gentamicin. Enterobacter aerogenes is a Gram-negative, oxidase negative, catalase positive, citrate positive, indole negative, rod-shaped bacterium. E. aerogenes is a nosocomial and pathogenic bacterium that causes opportunistic infections including most types of infections. The majority are sensitive to most antibiotics designed for this bacteria class, but this is complicated by their inducible resistance mechanisms, particularly lactamase which means that they quickly become resistant to standard antibiotics during treatment, requiring change in antibiotic to avoid worsening of the sepsis. Some of the infections caused by E. aerogenes result from specific antibiotic treatments, venous catheter insertions, and/or surgical procedures. E. aerogenes is generally found in the human gastrointestinal tract and does not generally cause disease in healthy individuals. It has been found to live in various wastes, hygienic chemicals, and soil. The bacterium also has some commercial significance – the hydrogen gas produced during fermentation has been experimented with using molasses as the substrate. It may spoil maple sap and syrup. E. coli is seen on the left and E. aerogenes on the right

Biochemical Characteristics of Enterobacter Aerosinosa

TSI A/Ag Lactose + ONPG + Indole – Methyl red – VP + Citrate + Lysine + Motility + H2S (TSI) – Ornithine + Arginine – PDA –