Phenotypic detection of Extended-spectrum â-lactamases (ESBLs) among Enterobacteriaceae and Pseudomonas aeruginosa from Mubi, Adamawa State, Nigeria

Background: Extended-Spectrum â-Lactamases (ESBLs) are group of enzymes produced by bacterial species which enable them to withstand the effect of cephalosporin antibiotics. They are mostly reported among Enterobacteriaceae and other Gram-negative bacteria especially Pseudomonas aeruginosa.Method: One hundred clinical samples comprising of urine, high vaginal swab (HVS), sputum, stool, semen and wound swab were analysed for bacterial growth. Bacterial species isolated were subjected to antibiotic susceptibility testing and phenotypic extended-spectrum â-lactamase production (ESBL).Result: Only 62(62.0%) of the clinical samples yielded bacterial growth which belonged to eight (8) genera. Escherichia coli (35.5%) was the most predominant, followed by P. aeruginosa (16.1%), while the least was P. mirabilis (1.6%). Extended-spectrum â-lactamases (ESBLs) was observed in 27/62 isolates, an overall prevalence of 43.5% with a predominance of E. coli (40.7%), followed by P. aeruginosa (22.2%). Although the number of non-ESBL isolates (35) was more than that of ESBL isolates (27%) but with no statistical difference (P=0.703). The antimicrobial susceptibility profile of all the isolates showed that 61(98.4%) and 56(90.3%) of the isolates were resistant to the â-lactam antibiotics, ceftriaxone and cefpodoxime respectively and were variable to other antibiotics. All the ESBL producers were found resistant (100%) to ceftriaxone and cefpodoxime (all cephalosporins). Also, all ESBL producing P. mirabilis, K. pneumoniae and P. agglomerans were found resistant (100%) not only to cephalosporins antibiotics, but also to other classes of antibiotics. However, resistance to all fluoroquinolones (sparfloxacin, ciprofloxacin, perfloxacin and ofloxacin) and gentamycin was moderately low especially among ESBL producing E. coli and P. aeruginosa, while ESBL producing K. pneumoniae was susceptible to the afore mentioned antibiotics.Conclusion: The finding of this study is worrisome considering the fact that most of the ESBLs strains exhibit MDR phenotype. This constitutes a threat to therapy not only in the hospital environment but also in the community. Keywords: Phenotypic, ESBLs, Enterobacteriaceae, Mub

Antimicrobial susceptibility pattern and plasmid-mediated antibacterial resistance in Staphylococcus aureus and coagulase-negative staphylococci

Background: Staphylococcal infections constitute problems to health care institutions. Its resistance to antibiotic has been associated with resistant plasmids (R-plasmid) that have the ability to mediate the production of drug inactivated  enzymes such as â-lactamase.Method: Forty five Staphylococcus aureus (S. aureus) and 15 Coagulase-negative Staphylococci (CoNS) were isolated from clinical samples and isolates subjected to antibiotic susceptibility testing, plasmid curing and plasmid DNA isolation.Result: The highest percentages isolates were recovered from urine samples and the least from high vagina swab and wound swab for S. aureus and CoNS respectively. The antibiogram showed that majority of S. aureus (95.6%) was resistant to cefuroxime and ceftazidime, while CoNS (93.3%) were more resistance to cefuroxime and gentamycin. (p=0.17). 24.4% S. aureus and 20% CoNS were resistant to more than 5 antibiotics with multiple antibiotic resistances (MAR) index of 0.33 to 0.89 for S. aureus and 0.56 to 0.78 for CoNS. Most of the S. aureus and CoNS were cured of their resistant markers showing that their R-markers may have been borne on plasmid. However, resistance to ciprofloxacin and ceftriaxone for CoNS may have been borne on chromosome as all the resistant markers were not cured. The percentage of S. aureus and CoNS cured of their R-plasmid were similar (p=0.25). Plasmids ranging from 2.03kbp to 23.13kbp were harboured by both S. aureus and CoNS.Conclusion: There is widespread antimicrobial resistance patterns and diverse plasmid profile of S. aureus and CoNS in this study. This data will be a useful baseline for further epidemiological investigations.Keywords: Plasmid, Staphylococcus, susceptibility, antimicrobials, resistance, curin