Browsing by Author "Adewuyi, O. R."

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Co-production of extended-spectrum beta-lactamases and metallo beta-lactamases among multi-drug resistant gram-negative bacteria isolates collected from tertiary hospitals in Oyo State, Nigeria
(FUDMA, 2020-09) Alabi, O. S.; Obisesan, A. O.; Taiwo, M. K.; Adewuyi, O. R.
Extended-spectrum beta-lactamases (ESBLs) and metallo beta-lactamases (MBLs) are compromising the chemotherapeutic use of cephalosporins and carbapenems respectively. This study investigated the burden of ESBLs and MBLs co-production among multi-drug resistant (MDR) Gram-negative bacteria collected from two tertiary hospitals in Oyo State. A total of 240 non-duplicated clinical isolates of Escherichia coli, Klebsiella spp. and Pseudomonas spp. were collected from the Microbiology units of two tertiary hospitals in Oyo State and their identities authenticated using standard identification techniques. Antimicrobial susceptibility testing was carried out by disc-diffusion method and isolates exhibiting resistance to 3 classes of antibiotics selected as MDR strains. ESBL and MBL production was detected by double-disc synergy test (DDST) and combined-disc-diffusion test (CDDT) respectively. Selected beta-lactamase genes were detected by PCR, amplicons sent out for sequencing and phylogenetic tree of the sequences constructed using Mega X software. MDR was exhibited by 43.8% of the isolates. ESBLs and MBLs were produced by 32.4% and 7.6% of the MDR isolates respectively. Co-production of ESBL and MBL was observed in 6.7% of the MDR isolates. BlaCTX-M-15 (67.7%), blaTEM-1 (55.9%), blaSHV-1 (47.1%), co-existing blaTEM + blaSHV, blaTEM + blaCTXM, blaCTX-M + blaSHV (each in 5.9%) and blaCTX-M +blaTEM + blaSHV (26.5%) were detected among the ESBLproducers. MBL genes were not detected among the MBL-producers. Only blaTEM-1 sequences showed two different claudes on the phylogenetic tree. The occurrence of MDR isolates co-harbouring different classes of beta-lactamse genes observed in this study is of public health concern and hence, requires stricter control of antibiotic use.
Susceptibility of Anopheles gambiae sensu lato (diptera: culicidae) to permethrin, deltamethrin and bendiocarb in Ibadan city, Southwest Nigeria
(Maxwell Scientific Organization, 2013-03) Ibrahim, K. T.; Popoola, K. O.; Adewuyi, O. R.; Adeogun, A. O.; Oricha, A. O.
This study was carried out to assess the resistance/susceptibility level of An. gambiae s.l, a major malaria vector in Ibadan metropolis, south west Nigeria, to two classes of insecticides approved by World Health Organization (WHO) for vector control. Anopheles larvae were collected from two communities (Ojoo and Bodija) within the metropolis and reared to adults. Two to three-day old, non-engorged female mosquitoes were exposed to discriminating dosages of 0.05% deltamethrin, 0.75% permethrin and 0.1% bendiocarb using WHO protocols and susceptibility test kits. Knockdown effect was recorded every 10 min and mortality scored 24 h after exposure. Species identification was by morphological characteristics only. The study revealed that the major malaria vector in Nigeria, An. gambiae s.l, were susceptible (mortality rate of 98.8%) to deltamethrin in Ojoo community, while Bodija recorded marginal susceptibility (87.5%). Both sites showed reduced susceptibility to permethrin and resistance to bendiocarb with 24 h post exposure mortalities ranging from 83.5 to 87.7% and 70.0 and 52.5%, respectively. The median Knockdown Time (KDT50) from 22-44.2 min for the pyrethroids (permethrin and deltamethrin), while that of carbamates (bendiocarb) range from 35.2 to 49.5 min. Resistance recorded in the field populations of An. gambiae s.l in Ibadan to bendiocarb was not observed in same population exposed to the pyrethroids (deltamethrin and permethrin) but with differential susceptibility. Therefore Bendiocarb may not be suitable as alternatives to mitigate pyrethroid resistance. A rationalised use of these insecticides coupled with regular monitoring of resistance status is essential to improve and evaluate the efficacy of the current vector control tools (ITN and IRS).