Multidrug efflux systems in Escherichia coli and Enterobacter cloacae obtained from wholesome broiler carcasses

Abstract

Members of the Enterobacteriaceae family are present in the intestines of man and animals as commensals or are important disease causing agents. Bacteria bearing multidrug efflux systems (MDR) are able to survive adverse ecological niches. Multiresistant Escherichia coli and Enterobacter cloacae isolates from wholesome broiler carcasses were investigated for the presence of MDR. Lowering of Minimal Inhibitory Concentration for antimicrobials in the presence of a proton-motive force (PMF) uncoupler was tested as a potential display of the MDR phenotype. PCR amplification of the genes encoding AcrA and AcrB, components of a MDR system was performed. Diversity of each species was ascertained by Pulsed-Field Gel Electrophoresis (PFGE) of DNA digested with endonuclease XbaI. For all the isolates, except E. coli 1 and E. cloacae 9, lowering of MIC or of the growth rate in the presence of antimicrobials was observed, indicating a PMF dependent resistance mechanism. Expected products of DNA amplification with acrAB derived primers was obtained with all E. coli strains and with two of the five E. cloacae strains. Dendrogram generated shows diverse pulsetypes, confirming the genetic diversity among the strains. An important issue and related public health is the fact that different models and mechanisms of antimicrobial resistance are present in a small number of non-pathogenic strains and isolated from the same origin. These may be sources of resistance genes to others microorganisms, among them, pathogenic strains.

Hexavalent chromium reduction by bacterial consortia and pure strains from an alkaline industrial effluent

“…aerogenes has already been characterized for its resistance to antibiotics by pump efflux mechanisms (Chevalier et al. 2008; Moreira et al. 2009), although resistance mechanisms to Cr(VI) have not been reported.…”

Antimicrobial Resistance, Biofilm Formation, and Phylogenetic Grouping of Uropathogenic Escherichia coli Isolates in Egypt: The Role of Efflux Pump-Mediated Resistance

“…Genomic DNA was extracted from all tested isolates by the boiling lysis method and 1 µL of the extract was used in all PCR reactions (18). The molecular identification of E. coli was performed by the PCR amplification of uspA gene, in a final reaction volume of 20 µL, using primers (Macrogen, Korea) listed in Table 1, at a concentration of 0.5 µM, and My Taq™ Red Mix (Bioline, UK) (19).…”