Background: Production of Extended Spectrum Beta-Lactamase (ESBL) by bacteria is a chronic problem in a health care set up. In order to have adequate information for treatment of bacterial infections especially ESBL producing isolates, it is crucial to understand the trends in the antibiotic-resistance pattern, occurrence and their geographical spread. The objective of this study was to determine the antimicrobial resistance pattern among phenotype ESBL producing isolates in northern Tanzania.

Methods: From July 2013 to January 2014, urine, pus and blood samples were collected from patients suspected to have bacterial infections at Kilimanjaro Christian Medical Centre in Moshi, Tanzania. The isolates were identified based on standard laboratory procedures. Antimicrobial susceptibility tests were carried out using various antimicrobial discs as per the recommendations of Clinical Laboratory Standard Institute.

Results: A total of 330 specimens were collected. They consisted of 46 urine, 264 pus (from wound) and 20 blood samples. Among isolated bacteria, ESBL producers were 29.7% (98) and non-producers were 70.5% (232). Escherichia coli and Klebsiella pneumoniae were the most isolated bacteria and dominant ESBL producers. ESBL production was highly associated with moderate condition at discharge and longer periods of admission. More than 60% of the ESBL producing E. coli were resistant to ceftazidime, cefpodoxime, cefotaxime, amoxycilin, ciprofloxacin, and gentamycin. More than 80% of ESBL producing K. pneumonia and Proteus mirabilis were resistant to ceftazidime and cefotaxime. Fifty four percent of ESBL producing K. pneumonia were resistant to gentamycin.

Conclusion : This study shows that ESLB phenotypes among Gram-negative bacteria are common among patients attending a tertiary hospital in northern in Tanzania. The findings suggest that clinical microbiology laboratories should take into account the diagnosis of ESBL producers in order to define the degree of the problem so as to establish a proper treatment protocol.