Quaternary ammonium compound based disinfectants are commonly used in pig and poultry husbandry to maintain farm hygiene. However, studies have shown that subinhibitory concentrations of these disinfectants may increase antibiotic resistance. Investigation of antibiotic susceptibility is usually assessed via the microbroth dilution method, although this conventional culture-based technique only provides information on the bacteriostatic activity of an antimicrobial agent. Therefore, experiments were performed to investigate the effect of prior benzalkonium chloride (BKC) exposure on the viability of subsequent ciprofloxacin (CIP) treated Escherichia coli. Following CIP treatment, bacterial cell counts were significantly higher after exposure to a subinhibitory BKC concentration than without BKC exposure. The flow cytometric results suggested a BKC-dependent onset of membrane damage and loss of membrane potential. Our results indicate a lower bactericidal effect of CIP treatment on BKC-exposed E. coli isolates compared to unexposed E. coli isolates.

中文翻译：

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亚抑制暴露于季铵化合物对畜牧业大肠杆菌菌株环丙沙星敏感性的影响。


季铵化合物消毒剂常用于猪和家禽饲养，以保持农场卫生。然而，研究表明，这些消毒剂的亚抑制浓度可能会增加抗生素耐药性。抗生素敏感性的研究通常通过微肉汤稀释法进行评估，尽管这种传统的基于培养的技术仅提供有关抗菌剂的抑菌活性的信息。因此，进行实验来研究先前的苯扎氯铵 (BKC) 暴露对随后环丙沙星 (CIP) 处理的大肠杆菌活力的影响。 CIP 处理后，暴露于亚抑制 BKC 浓度后的细菌细胞计数明显高于未暴露于 BKC 的情况。流式细胞术结果表明 BKC 依赖性膜损伤和膜电位损失的发生。我们的结果表明，与未暴露的大肠杆菌分离株相比，CIP 处理对 BKC 暴露的大肠杆菌分离株的杀菌效果较低。