Randall L P, Cooles S W, Coldham N G, Penuela E G, Mott A C, Woodward M J, Piddock L J V, Webber M A
Department of Food and Environmental Safety, Veterinary Laboratories Agency, New Haw, Surrey KT15 3NB, UK.
J Antimicrob Chemother. 2007 Dec;60(6):1273-80. doi: 10.1093/jac/dkm359. Epub 2007 Sep 25.
To determine if one passage of Salmonella enterica serovar Typhimurium in the presence of farm disinfectants selected for mutants with decreased susceptibility to disinfectants and/or antibiotics.
Eight Salmonella Typhimurium strains including field isolates and laboratory mutants were exposed to either a tar oil phenol (PFD) disinfectant, an oxidizing compound disinfectant (OXC), an aldehyde based disinfectant (ABD) or a dairy sterilizer disinfectant (based on quaternary ammonium biocide) in agar. The susceptibility of mutants obtained after disinfectant exposure to antibiotics and disinfectants was determined as was the accumulation of norfloxacin. The proteome of SL1344 after exposure to PFD and OXC was analysed using two-dimensional liquid chromatography mass spectrometry.
Strains with either acrB or tolC inactivated were more susceptible to most disinfectants than other strains. The majority (3/5) of mutants recovered after disinfectant exposure required statistically significantly longer exposure times to disinfectants than their parent strains to generate a 5 log kill. Small decreases in antibiotic susceptibility were observed but no mutants were multiply antibiotic-resistant (MAR). Notably exposure to ABD decreased susceptibility to ciprofloxacin in some strains. Mutants with increased disinfectant tolerance were able to survive and persist in chicks as well as in parent strains. Analysis of proteomes revealed significantly increased expression of the AcrAB-TolC efflux system after PFD exposure.
Data presented demonstrate that efflux pumps are required for intrinsic resistance to some disinfectants and that exposure to disinfectants can induce expression of the AcrAB-TolC efflux system, but that single exposure was insufficient to select for MAR strains.
确定肠炎沙门氏菌鼠伤寒血清型在存在为筛选出对消毒剂和/或抗生素敏感性降低的突变体而选择的农场消毒剂的情况下传代一次后的情况。
将包括现场分离株和实验室突变体在内的8株鼠伤寒沙门氏菌菌株在琼脂中暴露于煤焦油酚（PFD）消毒剂、氧化化合物消毒剂（OXC）、醛基消毒剂（ABD）或乳制品消毒器消毒剂（基于季铵类杀生剂）。测定消毒剂暴露后获得的突变体对抗生素和消毒剂的敏感性以及诺氟沙星的积累情况。使用二维液相色谱质谱法分析SL1344暴露于PFD和OXC后的蛋白质组。
acrB或tolC失活的菌株比其他菌株对大多数消毒剂更敏感。消毒剂暴露后回收的大多数（3/5）突变体与亲本菌株相比，产生5个对数杀灭所需的消毒剂暴露时间在统计学上显著更长。观察到抗生素敏感性有小幅下降，但没有突变体对多种抗生素耐药（MAR）。值得注意的是，暴露于ABD会使某些菌株对环丙沙星的敏感性降低。对消毒剂耐受性增加的突变体能够在雏鸡以及亲本菌株中存活和持续存在。蛋白质组分析显示，PFD暴露后AcrAB - TolC外排系统的表达显著增加。
所呈现的数据表明，外排泵是对某些消毒剂固有抗性所必需的，并且暴露于消毒剂可诱导AcrAB - TolC外排系统的表达，但单次暴露不足以筛选出MAR菌株。
