Multilocus sequence typing and biocide tolerance of Arcobacter butzleri from Danish broiler carcasses.
BACKGROUND
Arcobacter spp. have in recent years received increasing interest as potential emerging enteropathogens and zoonotic agents. They are associated with various animals including poultry and can be isolated from meat products. The possibilities of persistence and cross-contamination in slaughterhouses during meat processing are not well established. We have evaluated the occurrence and persistence of Arcobacter spp. in a Danish slaughterhouse and determined the sensitivity of isolates to sodium hypochlorite, a commonly used biocide.


RESULTS
Arcobacter contamination was examined in a broiler slaughterhouse by selective enrichment of 235 swabs from the processing line during two production days and after sanitizing in between. In total 13.6% of samples were positive for A. butzleri with the majority (29 of 32 isolates) originating from the evisceration machine. No Arcobacter spp. was isolated after cleaning. A. butzleri isolates confirmed by PCR were typed by multilocus sequence typing (MLST) resulting in 10 new sequence types (STs). Two sequence types were isolated on both processing days. Minimum inhibitory concentration (MIC) to sodium hypochlorite was determined to 0.5% hypochlorite biocide (500 ppm chlorine) for most isolates, which allows growth of A. butzleri within the working concentration of the biocide (0.2 - 0.5%).


CONCLUSIONS
A. butzleri was readily isolated from a Danish broiler slaughterhouse, primarily in the evisceration machine. Typing by MLST showed high strain variability but the recurrence of two STs indicate that some persistence or cross-contamination takes place. Importantly, the isolates tolerated sodium hypochlorite, a biocide commonly employed in slaughterhouse sanitizing, at levels close to the disinfection concentration, and thus, A. butzleri may survive the disinfection process although this was not observed in our study.
Department of Veterinary Disease Biology, University of Copenhagen, Faculty of Health and Medical Sciences, Stigboejlen 4, DK-1870 Frederiksberg, Denmark.
Louise Hesselbjerg
LH
Rasmussen
Jette
J
Kjeldgaard
Jens Peter
JP
Christensen
Hanne
H
Ingmer
D000003:Abattoirs / Q000295:instrumentation; D000818:Animals; D020640:Arcobacter / Q000145:classification / Q000187:drug effects* / Q000235:genetics*; D015373:Bacterial Typing Techniques; D002645:Chickens / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D003718:Denmark; D004202:Disinfectants / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004866:Equipment Contamination / Q000517:prevention & control; D004867:Equipment Design; D005506:Food Contamination / Q000517:prevention & control; D005516:Food Microbiology; D006801:Humans; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D060885:Multiplex Polymerase Chain Reaction; D010802:Phylogeny; D012973:Sodium Hypochlorite / Q000494:pharmacology*
D004269:DNA, Bacterial; D004202:Disinfectants; D012973:Sodium Hypochlorite