Frequency and Susceptibility Pattern of Extended Spectrum Beta Lactamase Producing Aerobic Gram Negative Bacteria in Post-Operative Infections

Extended spectrum β-lactamases occur commonly in the  aerobic Gram negative bacteria (AGNB) such as E. coli, Klebsiella spp., Proteus spp., Pseudomonas aeruginosa, Acinetobacter spp., etc. and have the ability to make these organisms resistant to cephalosporins  (e.g. ceftazidime, ceftriaxone, cefotaxime etc.), penicillins, and monobactams, i.e. aztreonam. However theses antibiotics become sensitive in the presence of clavulanic acid, an extended spectrum beta-lactamase (ESBL) inhibitor. ESBL enzymes do not influence cephamycins or carbapenems, i.e. meropenem, imipenem, etc. Major problems in surgery is wound infections after operations. High risks of wound infections are due to being immune-comprised on antibiotics, prolonged hospitalization and other factors in many cases. The current research determined various aerobic gram negative bacteria in post-operative wound infections at the College of Medical Laboratory Technology, the National Institute of Health, Islamabad, Pakistan. It also determined the frequency of ESBL in the organisms and established their susceptibility profile during the time period of the research. Infections caused by ESBL producers are a major problem in our post-operative patients. The commonest isolate was E. coli and the commonest ESBL producer was Klebsiella spp. Double disk synergy test is an effective method for screening of such isolates, and the practice of incorporating this test along with the routine sensitivity is recommended.