Antimicrobial Resistance and Multilocus Sequence Types of Finnish Campylobacter jejuni Isolates from Multiple Sources.

Antimicrobial susceptibility was determined for 805 domestic Campylobacter jejuni isolates obtained from broilers (n = 459), bovines (n = 120), human patients (n = 95), natural waters (n = 80), wild birds (n = 35) and zoo animals/enclosures (n = 16) with known multilocus sequence types (MLST) for 450 isolates. The minimum inhibitory concentration (MIC) values for erythromycin, tetracycline, streptomycin, gentamicin and the quinolones ciprofloxacin and nalidixic acid were determined with the VetMIC method. MICs were compared with MLST types to find possible associations between sequence type and resistance. The proportions of resistant isolates were 5% (broilers), 6.3% (natural waters), 11.4% (wild birds), 11.6% (human patients), 16.7% (bovines) and 31.3% (zoo). The most common resistance among the human and bovine isolates was quinolone resistance alone while resistance to streptomycin alone was most often detected among the broiler isolates and tetracycline resistance was most commonly observed in the wild bird, water and zoo isolates. No or negligible resistance to erythromycin or gentamicin was detected. In all data, 12/26 of the tetracycline-resistant isolates were also resistant to streptomycin (P < 0.001) and the clonal complex (CC) ST-1034 CC showed a high proportion of 75% (9/12) of tetracycline-resistant isolates, most originating from the zoo and broilers with closely associated MLST types from these sources. No association between quinolone resistance and MLST type was seen. The low percentage of resistant isolates among the domestic Campylobacter infections is most probably due to the long-term controlled use of antimicrobials. However, the higher percentage of tetracycline resistance observed among the zoo isolates could present a risk for zoo visitors of acquisition of resistant C. jejuni. The resistance pattern of tetracycline and streptomycin most often found in ST-1034 CC could indicate a common resistance acquisition mechanism commonly present in this CC. Overall, MLST typing was found to be a useful method in recognition of potential genetic lineages associated with resistance.

Characterization of the Campylobacter jejuni population in the barnacle geese reservoir.

Campylobacter spp. are the most common cause of bacterial gastroenteritis worldwide and have been isolated from a wide number of different hosts and environmental sources. Waterfowl is considered a natural reservoir for this zoonotic bacterium and may act as a potential infection source for human campylobacteriosis. In this study, faecal samples from 924 barnacle geese were tested for the presence of C. jejuni and C. coli. The resulting C. jejuni and C. coli populations were characterized by multilocus sequence typing (MLST), structure analysis by BAPS and phylogenetic analysis based on full genome sequences. The prevalences of C. jejuni in barnacle geese faeces were 11.5% and 23.1% in 2011 and 2012, respectively, and only 0.2% of the samples were positive for C. coli in both years. Furthermore, a possible adaption of the clonal complexes (CCs) ST-702 and ST-1034 to the barnacle geese reservoir was found, as these two CCs represented the majority of the typed isolates and were repeatedly isolated from different flocks at several time-points. Further core genome phylogenetic analysis using ClonalFrame revealed a formation of a distinct monophyletic lineage by these two CCs, suggesting a certain degree of clonality of the C. jejuni population adapted to barnacle geese. Therefore, although STs also commonly found in humans patients (e.g. ST-45) were among the barnacle geese C. jejuni isolates, this reservoir is probably an infrequent source for human campylobacteriosis.

Campylobacter jejuni prevalence and hygienic quality of retail bovine ground meat in Finland.

UNLABELLED: Detection of common genotypes of Campylobacter jejuni among Finnish human and bovine isolates, suggested that bovines may be a source for zoonotic Camp. jejuni infection. In addition, a Finnish epidemiological study implied the tasting and eating raw or undercooked beef as risk factors for acquiring campylobacteriosis. We therefore performed a study on the occurrence of Camp. jejuni in retail bovine ground meat in Helsinki by the use of both cultivation and PCR. During 2011 and 2012, 175 bovine ground meat samples were collected. None of the samples were Campylobacter positive by cultivation, and only one sample (0.6%) was Camp. jejuni positive by the use of PCR on template extracted directly from ground meat. According to our findings, Finnish bovine ground meat is an unlikely source for human campylobacteriosis. Additionally, the hygienic quality of bovine ground meat at retail level was screened and found to be good when monitored by aerobic micro-organisms, total thermotolerant coliforms and Eshericha coli. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides the first data on the occurrence of the zoonotic pathogen Campylobacter jejuni in Finnish bovine ground meat. This knowledge is important as part of future Campylobacter risk assessment, management and monitoring programs, particularly when assessing the relative attribution of poultry, pork and bovine meat to the burden of human campylobacteriosis. According to our results, Finnish bovine ground meat at retail level is of good hygienic quality.