Biocide tolerance and antibiotic resistance of Enterobacter spp. isolated from an Algerian hospital environment
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Date
2019-04-18
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elsevier
Abstract
Objectives: In this study, 77 Enterobacter spp. isolates from a collection of 175 Gram-negative bacilli
isolated from Tlemcen University Hospital Center (North-West of Algeria) were tested for antibiotic
resistance, biocide tolerance and genetic determinants of antimicrobial resistance.
Methods: The isolates were identified by 16S rDNA gene sequencing. Biocide tolerance was determined by
broth microdilution, and antibiotic resistance was determined by disk diffusion. Genetic determinants of
resistance were studied by PCR amplification using suitable primers.
Results: The most common Enterobacter species was Enterobacter cloacae (58.4%), followed by
Enterobacter hormaechei (24.7%). The most common antibiotic resistance was to ticarcillin either alone
or in combination with clavulanic acid (70.1%), followed by cefepime (68.8%), cefotaxime (63.6%),
ceftazidime (54.5%) and gentamicin (54.5%). Tobramycin was active against 87.0% of the isolates. Levels of
biocide tolerance were high for hexachlorophene and to a lesser extent for benzalkonium chloride. The
extended-spectrum β-lactamase genes blaTEM and blaCTX-M were detected in 44.2% and 36.4% of isolates,
respectively. Other antimicrobial resistance genes (ARGs) frequently detected were aac(6ʹ)-Ib (57.1%) and
sul2 (50.6%). Multidrug-resistant isolates carrying several ARGs were common. Significant positive
correlations were detected for efflux pump genes with ARGs and also between ARGs.
Conclusion: The results of this study reveal thatEnterobacter spp. isolates from hospital settings are both
resistant to clinically-used antibiotics and tolerant to biocides. Biocide tolerance could be an advantage
for antibiotic-resistant strains in hospitals.