Prevalence of multiple antibiotic resistance in 443 Campylobacter spp. isolated from humans and animals.
OBJECTIVE
In view of recent findings that a multidrug efflux pump CmeABC exists in Campylobacter jejuni, 391 C. jejuni and 52 Campylobacter coli of human and animal origin were examined for a multidrug resistance phenotype.


METHODS
The MICs of ampicillin, chloramphenicol, ciprofloxacin, erythromycin, kanamycin, tetracycline, cetrimide, triclosan, acridine orange, paraquat and ethidium bromide were determined. Resistance to organic solvents and the effect of salicylate (known inducer of the marRAB operon in Escherichia coli and Salmonella) were also examined.


RESULTS
Two C. coli and 13 C. jejuni isolates, mainly from pigs or poultry, were resistant to three or more antibiotics and 12 of these strains had reduced susceptibility to acridine orange and/or ethidium bromide. Strains (n = 20) that were less susceptible to acridine orange, ethidium bromide and triclosan were significantly more resistant (P < 0.05) to ampicillin, chloramphenicol, ciprofloxacin, erythromycin, nalidixic acid and tetracycline, with two- to four-fold increases in MIC values compared with strains (n = 20) most susceptible to acridine orange, ethidium bromide and triclosan. Growth of strains with 1 mM salicylate caused a small (up to two-fold) but statistically significant (P < or = 0.005) increase in the MICs of chloramphenicol, ciprofloxacin, erythromycin and tetracycline.


CONCLUSIONS
These data indicate that multiple antibiotic resistant (MAR)-like Campylobacter strains occur and it may be postulated that these may overexpress cmeABC or another efflux system.
Randall
L P
LP
Veterinary Laboratories Agency (Weybridge), New Haw, Addlestone, Surrey KT15 3NB, UK. l.randall@vla.defra.gsi.gov.uk
Ridley
A M
AM
Cooles
S W
SW
Sharma
M
M
Sayers
A R
AR
Pumbwe
L
L
Newell
D G
DG
Piddock
L J V
LJ
Woodward
M J
MJ
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002167:Campylobacter / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002169:Campylobacter Infections / Q000382:microbiology*; D004396:Coloring Agents / Q000494:pharmacology; D004202:Disinfectants / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D019450:Genes, MDR / Q000235:genetics; D006540:Herbicides / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests; D010269:Paraquat / Q000494:pharmacology; D010641:Phenotype; D012459:Salicylates / Q000494:pharmacology; D012997:Solvents; D001618:beta-Lactamases / Q000378:metabolism
D000900:Anti-Bacterial Agents; D004396:Coloring Agents; D004202:Disinfectants; D006540:Herbicides; D012459:Salicylates; D012997:Solvents; D001618:beta-Lactamases; D010269:Paraquat