Antimicrobial Resistance and β-Lactamase Production among Hospital Dumpsite Isolates ()
ABSTRACT
Metallo-β-Lactamases
(MBLs) and Extended Spectrum β-Lactamses (ESBLs) have emerged world-wide as a
significant source of β-lactam resistance. The emergence of MBLs and ESBLs
encoded on plasmids among Gram-negative pathogens in hospital dumpsites was
investigated. Soils of different government and private hospitals were collected
and processed following standard bacteriological techniques. Antimicrobial
susceptibility testing was carried out by the disk-diffusion technique using
Ceftazidime (30 μg), Cefuroxime (30 μg), Cefotaxime (30 μg), Cefixime (5 μg),
Trimethprim-sulfamethoxazole (25 μg), Gentamycin (100 μg)
Amoxicillin-Clavunalate (30 μg), Ciprofloxacin (5 μg), Ofloxacin (5 μg),
Nitrofurantoin (300 μg) and Imipenem (10 μg). The role of plasmids in
resistance was evaluated by subjecting isolates to curing using Sodium Dodecyl
Sulfate (SDS). ESBLs production by Double-Disk Synergy Test (DDST) was carried
out. Isolates resistant to Imipenem were subjected to a confirmatory test using
Modified Hodge’s test and to MBLs production by DDST. Eighty-two Gram-negative
isolates comprising of 32 (39.02%) Escherichia coli, 20 (24.39%) Serratia
marcescens, 14 (17.07%) Klebsiella pneumonia, 10 (12.28%) Proteus mirabilis and
6 (7.32%) Enterobacter aerogenes were obtained. Susceptibility results revealed
a 100% resistance of all isolates to Ceftazidime, Cefuroxime, Cefixime,
Amoxycillin-clavulanate and Cefotaxime. A total of 66 (80.48%) isolates
harboured plasmids out of which 26 (31.71%) isolates were ESBL producers. MBLs
production was observed in 8 (25.00%) E. coli, 2 (2.41%) Klebsiella pneumonia and 2 (2.41%) Proteus mirabilis isolates. All MBLs producing isolates were
ESBLs producers. The finding of highly resistant isolates producing ESBLs and
MBLs in a hospital environment is quite disturbing and should be addressed
urgently.
Share and Cite:
Egbule, O. (2016) Antimicrobial Resistance and
β-Lactamase Production among Hospital Dumpsite Isolates.
Journal of Environmental Protection,
7, 1057-1063. doi:
10.4236/jep.2016.77094.