Dynamics of Campylobacter colonization of a natural host, Sturnus vulgaris (European starling)

Campylobacter volucris sp. nov., isolated from black-headed gulls (Larus ridibundus)

During a study of the prevalence of Campylobacter jejuni in black-headed gulls (Larus ridibundus) in Sweden, three isolates, strains LMG 24379, LMG 24380T and LMG 24381, were initially identified as Campylobacter lari. Further characterization by both AFLP and whole-cell protein SDS-PAGE analyses revealed that they formed a distinct group in the genus Campylobacter. This unique position was confirmed by phenotypic characterization, 16S rRNA and hsp60 gene sequence analysis and DNA-DNA hybridizations. The combined data confirm that these isolates represent a novel species within the genus Campylobacter, for which the name Campylobacter volucris sp. nov. is proposed. The type strain is LMG 24380T (=CCUG 57498T).

Multilocus sequence typing of Campylobacter jejuni from broilers

Campylobacter jejuni isolates from a national Swedish Campylobacter monitoring in broilers were characterized by multilocus sequencing typing (MLST) in order to study the genetic diversity of this bacterial population. Isolates were initially characterized by pulsed-field gel electrophoresis (PFGE). One hundred were chosen for MLST genotyping. PFGE identified 69 distinct types compared to 44 different sequence types (STs) identified with MLST. Eighteen STs had not been described previously, while the remaining 26 STs were assigned to previously known clonal complexes. The majority of isolates were of genotypes noted in broilers and in humans in earlier studies. However, three clonal complexes, ST-206 complex, ST-677 complex and ST-1034 complex, previously associated with wild bird and environmental samples, were among the genotypes found. This study shows that most of the Swedish broiler isolates were of genotypes noted as common in broilers. However, it also highlights the potential influence of environmental sources on the broiler C. jejuni genotypes.

Novel clonal complexes with an unknown animal reservoir dominate Campylobacter jejuni isolates from river water in New Zealand

Campylobacter jejuni is widely distributed in the environment, and river water has been shown to carry high levels of the organism. In this study, 244 C. jejuni isolates from three river catchment areas in New Zealand were characterized using multilocus sequence typing. Forty-nine of the 88 sequence types identified were new. The most common sequence types identified were ST-2381 (30 isolates), ST-45 (25 isolates), and ST-1225 (23 isolates). The majority of the sequence types identified in the river water could be attributed to wild bird fecal contamination. Two novel clonal complexes (CC) were identified, namely, CC ST-2381 (11 sequence types, 46 isolates) and CC ST-3640 (6 sequence types, 12 isolates), in which all of the sequence types were new. CC ST-2381 was the largest complex identified among the isolates and was present in two of the three rivers. None of the sequence types associated with the novel complexes has been identified among human isolates. The ST-2381 complex is not related to complexes associated with cattle, sheep, or poultry. The source of the novel complexes has yet to be identified.

Clonal population structure and antimicrobial resistance of Campylobacter jejuni in chicken meat from Belgium

Campylobacter jejuni is one of the most important causes of human diarrhea worldwide. In the present work, multilocus sequence typing was used to study the genotypic diversity of 145 C. jejuni isolates from 135 chicken meat preparations sampled across Belgium. Isolates were further typed by pulsed-field gel electrophoresis, and their susceptibilities to six antimicrobials were determined. Fifty-seven sequence types (STs) were identified; 26.8% of the total typed isolates were ST-50, ST-45, or ST-257, belonging to clonal complex CC-21, CC-45, or CC-257, respectively. One clonal group comprised 22% (32/145) of all isolates, originating from five different companies and isolated over seven sampling months. Additionally, 53.1% of C. jejuni isolates were resistant to ciprofloxacin, and 48.2% were resistant to tetracycline; 28.9% (42/145) of all isolates were resistant to both ciprofloxacin and tetracycline. The correlation between certain C. jejuni clonal groups and resistance to ciprofloxacin and tetracycline was notable. C. jejuni isolates assigned to CC-21 (n = 35) were frequently resistant to ciprofloxacin (65.7%) and tetracycline (40%); however, 90% (18/20) of the isolates assigned to CC-45 were pansusceptible. The present study demonstrates that certain C. jejuni genotypes recur frequently in the chicken meat supply. The results of molecular typing, combined with data on sample sources, indicate a possible dissemination of C. jejuni clones with high resistance to ciprofloxacin and/or tetracycline. Whether certain clonal groups are common in the environment and repeatedly infect Belgian broiler flocks or whether they have the potential to persist on farms or in slaughterhouses needs further investigation.

Molecular epidemiology of Campylobacter jejuni isolates from wild-bird fecal material in children's playgrounds

In many countries relatively high notification rates of campylobacteriosis are observed in children under 5 years of age. Few studies have considered the role that environmental exposure plays in the epidemiology of these cases. Wild birds inhabit parks and playgrounds and are recognized carriers of Campylobacter, and young children are at greater risk of ingesting infective material due to their frequent hand-mouth contact. We investigated wild-bird fecal contamination in playgrounds in parks in a New Zealand city. A total of 192 samples of fresh and dried fecal material were cultured to determine the presence of Campylobacter spp. Campylobacter jejuni isolates were also characterized by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST), and the profiles obtained were compared with those of human isolates. C. jejuni was isolated from 12.5% of the samples. MLST identified members of clonal complexes ST-45, ST-682, and ST-177; all of these complexes have been recovered from wild birds in Europe. PFGE of ST-45 isolates resulted in profiles indistinguishable from those of isolated obtained from human cases in New Zealand. Members of the ST-177 and ST-682 complexes have been found in starlings (Sturnus vulgaris) in the United Kingdom, and these birds were common in playgrounds investigated in New Zealand in this study. We suggest that feces from wild birds in playgrounds could contribute to the occurrence of campylobacteriosis in preschool children. Further, the C. jejuni isolates obtained in this study belonged to clonal complexes associated with wild-bird populations in the northern hemisphere and could have been introduced into New Zealand in imported wild garden birds in the 19th century.