Phenotypic Detection of Extended Spectrum β-Lactamase and AmpC producing Enterobacteriaceae Isolated in A General Hospital

Abstract

Objective: The antibiotic resistance of Enterobacteriaceae is a worldwide preoccupation, and misuse
 antibiotics of beta-lactam group allowed the development of bacteria producing
 extended spectrum beta-lactamase and cephalosporinase AmpC enzymes type
 resistance. The aim of this study was to determine the frequency of these
 enzymes among strains isolated at the General Hospital in Douala, Cameroon.
 
 Methods: We
 conducted a cross-sectional study. For phenotypic detection of resistance
 enzymes, MASTDISCS™ test impregnated third and fourth generation
 cephalosporin’s was used by diffusion on Mueller Hinton agar. Measuring the
 inhibition areas and comparing the inhibition diameters determined the nature
 of the resistance mechanism.
 
 Results: This
 study included 195 strains of Enterobacteriaceae.
 The most frequent species were Escherichia
 coli and Klebsiella pneumoniae,
 with a frequency of 49.2% and 31.3% respectively. After determination of
 resistance phenotypes, 101 (51.8%) isolates were found to be producing
 resistance enzymes. The frequency of ESBL-producing Enterobacteriaceae was 19.5%; AmpC producing was 14.3% and both
 enzymes (AmpC + ESBL) 17.9%. E. coli
 and K. pneumoniae resistance rates
 were 90% and 83.7% for Cotrimoxazole, 82.5% and 78.3% for ciprofloxacin, 20%
 and 13.5% for Amikacin, respectively. Imipenem, Amikacin and Fosfomycin were
 the most active molecules with 4.9%, 19.8% and 33.6%, out of 101 resistant
 strains, respectively.
 
 Conclusion: This study showed a high frequency of resistance
 enzyme producing strains. This situation leads to resistance to antibiotics
 most commonly used. This finding justifies a change in prescription habits for
 protection of molecules that are still active. J Microbiol Infect Dis 2018; 8(3):113-119