Association between cyclohexane resistance in Salmonella of different serovars and increased, resistance to multiple antibiotics, disinfectants and dyes

A panel of 388 salmonellas of animal and human origin, comprising 35 seroty pes, was tested for resistance to cyclohexane and to a range of antibiotics , disinfectants and dyes. Cyclohexane resistance was detected in 41 isolate s (10.6%): these comprised members of the serovars Binza (1 of 15), Dublin (1 of 24), Enteritidis (1 of 61), Fischerkietz (4 of 5), Livingstone (9 of 11), Montevideo (1 of 32), Newport (4 of 23), Saint-paul (1 of 3), Senftenb erg (10 of 24) and Typhimurium (9 of 93). Most (39 of 41) of the cyclohexan e-resistant isolates were from poultry. Statistical analysis showed that th e cyclohexane-resistant strains were significantly more resistant than the cyclohexane-susceptible strains to ampicillin, chloramphenicol, ciprofloxac in, erythromycin, nalidixic acid, tetracycline, trimethoprim, cetrimide and triclosan. The multiresistance patterns seen,were typical of those caused by efflux pumps, such as AcrAB. The emergence of such resistance may play a n important role in the overall antibiotic resistance picture of Salmonella , with particular effect on ciprofloxacin.