Two major hospitals in Kano, North West Nigeria have recorded increasing resistance of clinical pathogens to broad spectrum β lactams, mediated by extended spectrum β- lactamase (ESβL) and non ESBLs. A study was therefore undertaken to determine the occurrence and prevalence of plasmid and chromosomal mediated AmpC βL and carbapenemase in addition to already known ESBL due to increasing resistance of pathogens from the two hospitals to carbapenems, cephamycins and flouroquinolones. Antibiogram tests and ESBL, AmpC and carbapenemase production tests were performed on all the isolates. AmpC and carbapenemase producers were further screened for AmpC inducibility and metallo beta lactamase production respectively. Majority of the isolates (> 80%) were resistant to both β-lactam and non β-lactam antibiotics. Reduced susceptibility to levofloxacin, nitrofurantoin, nalidixic acid and ofloxacin among the isolates were observed with the exception of P. aeruginosa which is totally resistant to imipenem and levofloxacin. An overall prevalence of 14.4%, 11.9% and 11.9.3% for ESβL, AmpC and carbapenemase was observed respectively. About 7.9% of the AmpC producers can over expressed the chromosomally mediated AmpC and 85.8% of the carbapenemase producers require metal for their action. Co-production of either of two and/or all of the enzymes was observed in E. coli, P. mirabilis and P. aeruginosa. Antibiotic resistance among isolates from the two hospitals is increasing and the major cause of this resistance in the pathogens studied are production of AmpC, carbapenemase (especially Metallo β- lactamase) in addition to already known ESBL enzymes by the pathogens. Some of the isolates also possess the capacity to elaborate two or more of the enzymes concurrently, which would renders them resistant to a multitude of antibiotics.
AmpC β-lactamases; extended spectrum β-lactamases; coexistence; prevalence; Gram negative bacteria
