The possible contamination of food and/or food-producing animals with multidrug resistant bacteria including AmpC-producing Pseudomonas aeruginosa is considered a potential source for the wide dissemination of AmpC β-lactamase in the community. This portends public health risks for the populace -owing to the multidrug resistant nature of these organisms. There is paucity of data on the prevalence of AmpCproducing bacteria in Abakaliki, Nigeria -which was why this study was carried out. A total of 40 feacal swab samples from cow dung in a local abattoir were bacteriologically examined for the isolation and antimicrobial susceptibility testing of P. aeruginosa isolates using standard microbiological procedures on cetrimide selective agar and Kirby-Bauer disk diffusion method respectively. AmpC β-lactamase was phenotypically confirmed using the ceftazidime-imipenem antagonism test (CIAT). A total of 12 P. aeruginosa isolates were recovered from the samples; and they showed varied levels of resistance to the tested antibiotics especially to cefoxitin, ertapenem, oxacillin, amikacin and cefotaxime. Among the 12 P. aeruginosa isolates, AmpC β-lactamase was phenotypically detected in 3 (25%) isolates by the CIAT method. This study has presumptively shown that AmpC β-lactamase-producing P. aeruginosa isolates occur in abattoir. Thus, molecular characterization of the genes that encode AmpC β-lactamase production in this organism is crucial for a reliable epidemiological investigation into the possible emergence and dissemination of AmpC positive bacteria in the community. monitoring and possibly a ban on the use of antibiotics in the production and/or rearing of food producing animals in order to assuage the emergence and spread of drug resistant bacteria in the community [7,19,21]. Thus, this study presumptively detected the occurrence of AmpC-producing P. aeruginosa isolates from feacal matter of cow in a local abattoir.
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Materials and Methods
Sample collection and processingA total of forty (40) swab samples were collected from feacal matter of cow in a local abattoir using sterile swab sticks. After collection, each of the swab sticks was returned into their respective containers, labeled and transported to the Microbiology Laboratory Unit of Ebonyi State University, Abakaliki for bacteriological analysis.
Isolation and identification of Pseudomonas aeruginosaCetrimide selective agar (Oxoid, UK) containing 10 ml of glycerol was used for the selective isolation of P. aeruginosa from the test samples. Each of the feacal swab samples was inoculated in 5 ml double strength of freshly prepared nutrient broth (Oxoid, UK) and incubated for 18-24 hours at 30 o C. A loopful of the broth culture was aseptically streaked on cetrimide selective agar plates; and the plates were incubated at 30 o C 18-24 hours. Suspected colonies were inoculated onto freshly prepared cetrimide selective agar for the isolation of pure cultures of P. aeruginosa. P. aeruginosa produces greenish/bluish pigmentation on cetrimide selec...