First detection of the antiseptic resistance gene qacA/B in Enterococcus faecalis.
Resistance to disinfectants is well investigated in staphylococci and pseudomonads but nearly unexplored in bacteria of the genus Enterococcus, despite their rising significance as nosocomial pathogens. In this study, Enterococcus faecalis (n=585) from blood (n=42) and stool (n=109) of hospitalized humans, from faeces of farm animals (n=226), and from food (milk and dairy products, n=96; meat and meat products, n=112) were screened for the presence of qac-genes (qacA, qacB, qacC, smr [qacC+qacD], qacEΔ1, qacG, qacH, qacJ) via PCR. The isolates' susceptibility to a quaternary ammonium compound (didecyldimethylammoniumchloride, DDAC) and antibiotics was assessed by microdilution. Four E. faecalis strains were positive for qac-genes: qacA/B was found in one isolate from cattle and one isolate from human blood; smr (qacC+qacD) was detected in one isolate from human stool and in one isolate from cheese ("Camembert"). The sequences of the qacA/B-amplicons differed in two basepairs. DDAC had an elevated minimum inhibitory concentration (MIC) of 2.45-3.5 mg/L in one qacA/B-positive strain from human blood, whereas the other qac-gene carriers had wild-type MIC-values for DDAC (1.05 mg/L). This is the first detection of qacA/B in the genus Enterococcus.
Technische Universität München, Freising, Germany.
Meike
M
Bischoff
Johann
J
Bauer
Petra
P
Preikschat
Karin
K
Schwaiger
Gabriele
G
Mölle
Christina
C
Hölzel
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002417:Cattle; D003611:Dairy Products / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005798:Genes, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology; D006801:Humans; D008461:Meat Products / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D009154:Mutation; D016133:Polymerase Chain Reaction; D044967:Serum
D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local