Enterobacter spp.: - An emerging nosocomial infection

The taxonomic evolution of family Enterobacteriaceae has been a dynamic process and continued throughout the 1980s and 1990s. Today, there are more than 30 distinct genera and more than 100 species within the family. Enterobacter genus of family Enterobacteriaceae has gained in recent years the attention of taxonomists, microbiologists and clinicians alike. The members of genus Enterobacter are motile gram negative enteric bacilli belonging to the family Enterobacteriaceae. Enterobacter spp. are not considered to be the primary human pathogens; however like most Enterobacteriaceae they are capable of causing opportunistic infections in hospitalised or debilitated patients. A National Nosocomial Infection Surveillance System (NNIS) study found that Enterobacter accounts for 5 to 11% of all nosocomially transmitted blood, wound, and respiratory tract and urinary tract infections. Until recently epidemiological studies on genus Enterobacter. have been based essentially up on the study of phenotypic traits such as biochemical profiles, antibiotic resistance, serological, bacteriocin and phage typing although often very useful, there are some problems associated with them inability to demonstrate strain to strain variation, unavailability of specific reagents, poor sensitivity to phage, nonspecific agglutination are some of the technical pitfalls inherent to the phenotypic studies. The single most alarming trend regarding the genus Enterobacter is the increasing incidence of serious life threatening infections caused by strains resistant to multiple antibiotics. Some of the processes responsible for quick generation of resistance are plasmid -lactamase and chromosomal cephalosporinase, variability of target of the antibiotic and modification of envelope permeability, including alteration of porins (OMPs) and expression of drug efflux. Enterobacter spp. appears well adapted for survival and threats to cause immense mortality & morbidity by the proliferation of highly drug resistant strains both in the community and hospital environment.