Extended Spectrum Beta Lactamase (ESBL) producing bacteria are of great concern to health care because of their resistant to β-lactam antibiotics. The bacteria in thirty samples of fruits and vegetables salads purchased from food vendors were isolated and identified with standard microbiological methods. The Gram negative bacteria recovered were screened for ESBL production by the Double Disk Synergy Test (DDST) [with amoxicillin-clavulanic acid (20/10µg), ceftriaxone (30µg) and ceftazidime (30µg)] and Brilliance ESBL agar (BEA). The total coliform count in the fruit and vegetable salads was in the range 2.3 - 19.1 x 104cfu/g and 2.8 - 19.4 x 104cfu/g respectively. Ninety-eight (98) gram negative bacteria were recovered from the salad samples. They were: Escherichia coli (34.7%), Citrobacter freundii (21.4%), Enterobacter cloacae (10.2%), Enterobacter aerogenes (9.2%), Pseudomonas aeruginosa (9.2%). Klebsiella oxytoca (8.2%), Klebsiella pneumoniae (4.1%) and Proteus mirabilis (3.1%). For ESBL production using DDST, 43. 9% (43) of the isolates were positive for the test. On the chromogenic agar, 68.4% (67) showed the expected colour change as outlined by the manufacturer. However, five strains of K. oxytoca showed a blue growth while sixteen of C. freundii had brown growth. ESBL producing E. coli that were not detected with DDST grew on BEA. ESBL producing bacteria are threat in foods especially in ready-to-eat salads that do not undergo any heat processing before consumption. Therefore, there is need for vendors of this food to practise strict food hygiene to avert food poisoning by these pathogens.
Key words: Antibiotics, ESBL bacteria, fruits, vegetables, salads, Brilliance ESBL agar
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