Association ofqacEandqacEΔ1 with multiple resistance to antibiotics and antiseptics in clinical isolates of Gram-negative bacteria

Abstract

Clinical isolates of Enterobacter cloacae, Citrobacter freundii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia were tested for resistance to antibiotics and to the antiseptics benzalkonium chloride and cetyltrimethylammonium bromide. Furthermore, they were examined for the presence of the resistance genes qacE and qacEDelta1. qacEDelta1 was detected by PCR in 10% of all (n=103) and in 81% of multiply antibiotic-resistant strains (n=15). qacE was found in only one of 37 P. aeruginosa strains. The minimum inhibitory concentrations of benzalkonium chloride, cetyltrimethylammonium bromide, and ethidium bromide were not significantly different for qacEDelta1/qacE-positive or -negative strains. Our data indicate that multiply antibiotic-resistant Gram-negative bacteria are not necessarily more resistant to quaternary ammonium compounds than antibiotic-sensitive strains even though qacE or qacEDelta1 is present.

Comparative Global Gene Expression Profiles of Wild-TypeYersinia pestisCO92 and Its Braun Lipoprotein Mutant at Flea and Human Body Temperatures

“…One of these genes encodes QacE (Table 2), which was shown to be associated with multiple resistances to antibiotics and antiseptics in clinical isolates of Enterobacter cloacae , Citrobacter freundii , Pseudomonas aeruginosa , and Stenotrophomonas maltophilia [45], as well as environmental and clinical isolates of Vibrio parahaemolyticus and V. cholerae [46]. Two genes related to spheroplast formation (pesticin and a gene similar to the Bacillus subtilis stage V sporulation protein R) were down-regulated in the Δ lpp mutant, compared to WT Y. pestis (Table 2).…”

Detection of Antiseptic-Resistance Genes in Pseudomonas and Acinetobacter spp. Isolated From Burn Patients

“…The PCR was conducted with 35 cycles as follows: denaturation at 94˚C for 45 seconds , annealing at 55˚C for 45 seconds, and extension at 72˚C for 45 seconds in a thermocycler machine (ABI Geneamp 9700, USA). Preincubation at 94˚C for 3 minutes, and a final extension cycle at 72˚C for 8 minutes, were also included (11). The products of the PCR were detected by electrophoresis on a 1.5% agarose gel in a TAE buffer.…”

“…The PCR program for qac ΔE1 detection was carried out for one cycle at 93˚C for 2 minutes followed by 35 cycles which included: denaturation step at 94˚C for 30 seconds, annealing step at 55˚C for 30 seconds and extension step at 72˚C for one minute. A final extension step was done at 72˚C for 5 minutes at the end (11). …”

“…The qac E gene (including its attenuated variant qac EΔ1) is widespread in Gram-negative bacteria, mainly in Enterobacteriaceae and Pseudomonas spp. because these genes are located in class 1 integrons, which in Gram-negative bacteria commonly harbor qac EΔ1 (11). The qac ΔE1 gene is a mutation of the qac E gene, which acts as a multidrug transfer gene (12).…”

Poorly processed reusable surface disinfection tissue dispensers may be a source of infection

“…Originally resistant isolates probably experienced lesser stress during adaptation, and hence displayed only marginal increase in biofilm formation [13]. Isolates with a resistance to BAC are also commonly resistant to different types of antibiotics [14,15] or to other types of surfactants such as benzethonium chloride or alkyldiaminoethylglycine [16]. Assuming that most isolates in clinical practice are not originally resistant, one should expect a rather high biofilm forming capacity from Gram-negative isolates surviving in or even multiplying in BAC use solution.…”