About Enterobacter Aerogenes Bacterium

A member of the Enterobacteriaceae family, Enterobacter aerogenes is bacterium related to salmonella and E. coli. Size-wise, Enterobacter aerogenes is smaller than many of its microbial cousins, but its occurrence in hospitals has made it of particular interest to the medical community. Its bacteriology, illnesses, risk factors, predilections, and treatment have been the subject of extensive study.

Bacteriology

• Enterobacter aerogenes is a bacillus, so under a microscope, it looks like a straight rod. As a facultative anaerobe, it prefers environments with little or no oxygen, such as feces, sewage plants, and soil. However, it can also survive and even grow where oxygen is abundant.

  In a Petri dish, Enterobacter aerogenes forms round, white colonies that curve convexly. Its optimal growing temperature ranges from 30 to 37 degrees Celsius, and MacConkey agar, which contains salts, dyes, and nutrients from milk, is its laboratory medium of choice.

Illnesses

• Enterobacter aerogenes cause a wide range of illnesses. These illnesses include bacteremia, osteomyelitis, and septic arthritis, as well as infections of the urinary tract, gastrointestinal tract, respiratory tract, and skin.

Risk Factors

• Enterobacter aerogenes is a nosocomial opportunistic pathogen. That is, it causes illness after its host has already been weakened, and it commonly resides in hospitals. For that reason, its risk factors include hospital stays lasting two weeks or longer, invasive surgeries, and the use of antibiotics. Intensive care unit visits are another.

  Enterobacter aerogenes infects healthy individuals only rarely.

Predilections

• As with other Enterobacter species, Enterobacter aerogenes has no predilection for race. However, it does occur more frequently among infants, toddlers, and the elderly, especially among males.

Treatment

• Enterobacter aerogenes is resistant to most antibiotics. Its resistance to β-lactam antibiotics, chloramphenicol quinolones, and tetracycline is well documented in scientific literature, and some researchers have proposed the reuse of "old" drugs---that is, drugs that were popular in previous decades---in response. One study by Thiolas et al. (2005) suggests that a combination of drugs would best accommodate those infected by Enterobacter aerogenes.