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Masters Degrees (Clinical Medicine)

Permanent URI for this collectionhttps://hdl.handle.net/10413/7796

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Browsing Masters Degrees (Clinical Medicine) by Subject "Antibiotic."

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    Resistance to β-lactam and fluoroqinolone antibiotics in enterobacteriaceae from chicken : an observational study in Maputo, Mozambique.
    (2016) Faife, Sara Lino.; Essack, Sabiha Yusuf.; Sundsfjord, Arnfinn Staale.; Zimba, Tomas Francisco.
    Extended-spectrum β-lactamase (ESBL) and/or plasmid-mediated AmpC (pAmpC)-producing Enterobacteriaceae with co-resistance to fluoroquinolones are increasingly identified in food-borne pathogens globally. This study investigated ESBL- and pAmpC-mediated β-lactam resistance as well as plasmid-mediated fluoroquinolone resistance in 198 samples taken from 99 frozen chickens (99 samples from the liquid thaw and 99 from carcass swabs), Brazil, South Africa and Mozambique each produced 33 chicken. Species identification was undertaken using in-house biochemical tests and antibiotic susceptibility was ascertained by the disc diffusion test following CLSI guidelines. ESBL production was determined using the double-disk synergy test and isolates were subjected to PCR to detect the presence of blaCTX-M, blaSHV, blaTEM, blaCMY, blaMOX, blaFOX, blaDHA, qnrB, qnrD, qnrS and qepA genes. A random selection of CTX-M genes was sequenced. The 198 samples yielded 27 putative ESBL-positive isolates: Citrobacter diversus (1), Citrobacter freundii (3), Enterobacter aglomerans (1), Enterobacter cloacae (1) and Escherichia coli (21). Of the 27 isolates, 19 were from South African chicken, five from Mozambican chicken and three from Brazilian chicken. Resistance to ampicillin was 100,0%, followed by 88.8% to ceftriaxone, 77.8% to trimethoprim-sulphamethoxazole, 74.0% to cefotaxime, 70.4% to ciprofloxacin, 66.6% to ceftazidime, 22.2% to cefoxitin and 7.6% to gentamicin. Multi-drug resistance was evident in 19 (70.4%) isolates, 15 of which were from South Africa. The predominant ESBL gene was blaSHV (85%), followed by blaCTX-M (62.9%) and blaTEM (44.4%) whilst blaMOX (33, 3%) and blaDHA (33.3%) were the most common pAmpC genes. The predominant plasmid-mediated fluoroquinolone-resistance gene was qepA (22.2%). DNA sequencing of the blaCTX-M genes putatively identified differentiation of the E. coli and Citrobacter spp. isolates. There was no strong evidence of clonality, however, South African isolates shared more similarity. qnr and qepA genes were predominantly identified in South African E. coli isolates while CTX-M and SHV genes were prevalent in isolates from diverse origins. The Mozambican population is thus exposed to a reservoir of plasmid-mediated and hence, mobile β-lactam and fluoroquinolone resistance genes from imported, and to a lesser extent, locally-produced chicken. The complexity and diversity of mobile resistance genes combinations and permutations is of concern in the food safety context.blaCTX-M-55/-79/-101/-164, with blaCTX-M-164 being most common. ERIC–PCR profiles allowed the differentiation of the E. coli and Citrobacter spp. isolates. There was no strong evidence of clonality, however, South African isolates shared more similarity. qnr and qepA genes were predominantly identified in South African E. coli isolates while CTX-M and SHV genes were prevalent in isolates from diverse origins. The Mozambican population is thus exposed to a reservoir of plasmid-mediated and hence, mobile β-lactam and fluoroquinolone resistance genes from imported, and to a lesser extent, locally-produced chicken. The complexity and diversity of mobile resistance genes combinations and permutations is of concern in the food safety context.