A study on the detection of extended spectrum beta lactamase producers and class I intergrons in e. coli isolates from urinary tract infected patients at UTH.

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Chirwa, Emmanuel
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The University of Zambia
Escherichia coli that produce extended spectrum beta lactamase (ESBL) enzymes pose a global challenge in the management of urinary tract infections (UTIs) caused by these organisms. Beta lactamases are the primary cause of resistance to beta lactam antibiotics. These enzymes confer multi drug resistance (MDR) thus limiting and complicating treatment options. The beta lactamase resistant genes are usually encoded on plasmids and often confer resistance to other classes of antibiotics, further underscoring their clinical significance. In Zambia there is paucity of data available in relation to UTIs caused by ESBL producing E. coli. There is little information about genes responsible for these enzymes and the organisms’ susceptibility patterns to commonly used antibiotics. This cross sectional study used urine samples from 327 consenting patients from the University Teaching Hospital in Lusaka, Zambia. The ESBL producing isolates were obtained by culturing urine samples on MacConkey agar supplemented with cefotaxime followed by polymerase chain reaction (PCR) to detect the resistant genes in positive isolates. A questionnaire was used to collect information from patients for assessment of risk factors relating to infection with ESBL producing E. coli. The antibiotic susceptibility pattern was determined by using the disc diffusion method. Of a total 327 samples analyzed, 15 (4.6%) were positive for ESBL producing E. coli. Genes of resistance significance that included the blaINT blaCTXM, blaSHV and blaTEM were detected. There was 100% resistance of the isolates to Cotrimoxazole, ampicillin and cefotaxime while no resistance (0%) was detected to Nitrofurantoin. All the ESBL producers had MDR (at least 30%) patterns. None of the risk factors was statistically significant in this study. This study detected the presence of ESBLs and class I integrons in MDR E. coli in UTIs at the University Teaching Hospital in Zambia. This prompts the need for antimicrobial resistance surveillance to monitor hospital resistance patterns for these microorganisms.
Thesis of Medical Microbiology