Extended spectrum beta-lactamases in urinary gram -negative bacilli and their susceptibility pattern

ABSTRACT

Beta-lactamases of Gram-negative bacteria are the most important mechanism of resistance against beta-lactams. Two types of beta-lactamases can confer resistance against third generation cephalosporins; inducible chromosomal beta-lactamases, and extended-spectrum beta-lactamases. The extended-spectrum beta-lactamases producing strains of Enterobacteriaceae have emerged as a major problem in hospitalized as well as community based infections resulting in range of infections from uncomplicated urinary tract infection to life threatening sepsis. To find out the prevalence of extended-spectrum beta-lactamases producing Gram- negative bacilli among urinary isolates and their sensitivity pattern. The study was conducted at the Microbiology Department of Fauji Foundation Hospital, Rawalpindi over a period of two years [April 2004-March 2006]. Multidrug resistance and extended-spectrum beta-lactamases production was studied in 111 enteric Gram-negative bacilli isolated from urine of symptomatic patients [1-70 years] including males and females from indoor and outdoor patients by using double disc diffusion technique. Prevalence of extended-spectrum beta-lactamases production was seen in 71 [61.2%] enteric gram-negative organisms, the most prevalent gram-negative organism was Klebsiella pneumoniae 40 [71.4%] followed by Escherichia coli 27 [62.8%] and Pseudomonas aeruginosa 3 [25%]. The extended-spectrum beta-lactamases producers were more prevalent in indoor patients 63 [88.7%] compared to outdoor patients 8 [11.3%], more in females 43 [60.6%] than males, 28 [39.4%]. The extended-spectrum beta-lactamases producing gram-negative rods had more antibiotic-resistant profile than non-producers. All enteric gram negative rods should be tested for the production of extended-spectrum beta-lactamases in routine microbiology laboratory