Elucidation of colonization time and prevalence of thermophilic Campylobacter species during turkey rearing using multiplex polymerase chain reaction

Campylobacter Colonization and Diversity in Young Turkeys in the Context of Gastrointestinal Distress and Antimicrobial Treatment

Young turkeys are vulnerable to undifferentiated gastrointestinal distress, including "irritable and crabby syndrome" (ICS), which compromises flock performance and is typically treated with a combination of penicillin and gentamicin (P/G). However, the effects of ICS and P/G treatment on Campylobacter remain poorly understood. We investigated the impact of ICS and P/G treatment on Campylobacter levels and diversity in four flocks from three turkey farms. Cecum and jejunum samples were analyzed weekly from day of hatch to week 4-5. All four flocks became colonized with multidrug resistant (MDR) Campylobacter jejuni and C. coli by week 2-3, and two developed ICS. ICS and P/G treatment did not significantly impact total Campylobacter levels or strain genotypes but impacted species and antimicrobial resistance (AMR) profiles. One flock was raised under antibiotic-free (ABF) conditions while another flock at the same farm was raised conventionally. The ABF flock did not develop ICS while its counterpart did. However, Campylobacter strains, AMR profiles and sequence types were generally shared between these two flocks. Our findings suggest that ICS and P/G treatment impacted Campylobacter population dynamics in commercial young turkey flocks, and that ABF flocks may become readily colonized by MDR strains from non-ABF flocks at the same farm.

Multilocus sequence typing of Campylobacter jejuni and Campylobacter coli to identify potential sources of colonization in commercial turkey farms

Poultry are the main reservoir for thermophilic Campylobacter spp., which is the most common causative agent of human bacterial gastroenteritis. The epidemiology of Campylobacter in poultry, particularly in turkeys, is not completely understood. This study aimed at identifying potential sources and transmission routes of thermophilic Campylobacter spp. in commercial turkey farms. C. jejuni and C. coli isolates from breeders (n = 29, 20 C. jejuni and 9 C. coli) and their progeny (n = 51, 18 C. jejuni and 33 C. coli) reared in two different farms for three sequential production cycles were analysed by multilocus sequence typing (MLST). Strains (n = 88, 42 C. jejuni and 46 C. coli) isolated from environmental (i.e. anteroom and in-house overshoes), water (i.e. drinkers and water line), and pest (i.e. flies, Alphitobius diaperinus, and mice) sources were also examined. MLST of C. jejuni and C. coli isolates resulted in 13 and 12 different sequence types (STs) belonging to six and one previously-described clonal complexes (CCs), respectively. Three novel STs were identified. Genetic similarities were detected between isolates from fattening turkeys and the considered environmental, water, and pest sources, and with the breeders to a lesser extent. Source attribution analysis estimated that environmental and water sources accounted for most (∼75%) of fattening turkey isolates and were therefore identified as the most likely sources of flock colonization, followed by pests (∼20%) and breeders (∼5%). These sources may thus be targeted by control measures to mitigate the risk of Campylobacter colonization in commercial turkeys. RESEARCH HIGHLIGHTS High occurrence of C. jejuni and C. coli in commercial turkey flocks. High genetic diversity of C. jejuni and C. coli in commercial turkey flocks. Horizontal transmission responsible for Campylobacter colonization of commercial turkey flocks. Environmental and water sources involved in Campylobacter colonization of commercial turkey flocks. Strategies for prevention and control of Campylobacter colonization of commercial turkey flocks are needed.

Antimicrobial resistance of Campylobacter isolates from small scale and backyard chicken in Kenya

BACKGROUND

Thermophilic Campylobacter species are a major cause of bacterial foodborne diarrhoea in humans worldwide. Poultry and their products are the predominant source for human campylobacteriosis. Resistance of Campylobacter to antibiotics is increasing worldwide, but little is known about the antibiotic resistance in Campylobacter isolated from chicken in Kenya. In this study, 35 suspected Campylobacter strains isolated from faeces and cloacal swabs of chicken were tested for their susceptibility to seven antibiotics using a broth microdilution assay and molecular biological investigations.

RESULTS

Overall, DNA of thermophilic Campylobacter was identified in 53 samples by PCR (34 C. jejuni, 18 C. coli and one mix of both species) but only 35 Campylobacter isolates (31 C. jejuni and 4 C. coli) could be re-cultivated after transportation to Germany. Isolates were tested for their susceptibility to antibiotics using a broth microdilution assay. Additionally, molecular biological detection of antibiotic resistance genes was carried out. C. jejuni isolates showed a high rate of resistance to nalidixic acid, tetracycline and ciprofloxacin of 77.4, 71.0 and 71.0 %, respectively. Low resistance (25.8 %) was detected for gentamicin and chloramphenicol. Multidrug resistance in C. jejuni could be detected in 19 (61.3 %) isolates. Resistance pattern of C. coli isolates was comparable. Resistance to ciprofloxacin was confirmed by MAMA-PCR and PCR-RFLP in all phenotypically resistant isolates. The tet(O) gene was detected only in 54.5 % of tetracycline resistant C. jejuni isolates. The tet(A) gene, which is also responsible for tetracycline resistance, was found in 90.3 % of C. jejuni and in all C. coli isolates. Thirteen phenotypically erythromycin-resistant isolates could not be characterised by using PCR-RFLP and MAMA-PCR.

CONCLUSIONS

To the best of our knowledge, this study is the first report about resistance to antibiotics in thermophilic Campylobacter originating from chicken in Kenya. Campylobacter spp. show a high level of resistance to ciprofloxacin, nalidixic acid and tetracycline but also a remarkable one to chloramphenicol and gentamicin and they are multidrug resistant. Resistance to antibiotics is a global public health concern. In Kenya, resistance surveillance needs further attention in the future. Efforts to establish at least a National Laboratory with facilities for performing phenotypic and genotypic characterization of thermophilic Campylobacter is highly recommended.

Prevalence, genotyping and risk factors of thermophilic Campylobacter spreading in organic turkey farms in Germany

BACKGROUND

The need for organic food of animal origin has increased rapidly in recent years. However, effects of organic animal husbandry on food safety have not been rigorously tested especially in meat turkey flocks. This study provides for the first time an overview on the prevalence and genetic diversity of Campylobacter species (spp.) in five organic meat turkey farms located in different regions in Germany, as well as on potential risk factors of bacterial spreading. Thirty cloacal swabs as well as water samples and darkling beetles were collected from each flock and examined for the presence of Campylobacter by conventional and molecular biological methods. The isolates were genotyped by flaA-RFLP.

RESULTS

Campylobacter spp. were detected in cloacal swabs in all 5 turkey flocks with prevalence ranged from 90.0 to 100 %. 13 cloacal swabs collected from birds in farm III and IV were harboured mixed population of thermophilic campylobacters. In total, from 158 Campylobacter isolated from turkeys 89 (56.33 %) were identified as C. coli and 69 (43.76 %) as C. jejuni. Three Campylobacter (2 C. jejuni and 1 C. coli) were detected in drinkers of two farms and 3 C. coli were isolated from darkling beetles of one farm. No Campylobacter were isolated from main water tanks. flaA-RFLP assay showed that turkey farms can harbour more than one genotype. In a single turkey two different genotypes could be detected. The genotypes of campylobacters isolated from water samples or beetles were identical with those isolated from turkeys. No effect was found of some environmental parameters [ammonia concentration (NH3), carbon dioxide concentration (CO2), relative humidity (RH) and air temperature)] on Campylobacter prevalence in organic turkey farms. Additionally, drinking water and darkling beetles might be considered as risk factors for the spreading of Campylobacter in turkey flocks.

CONCLUSIONS

This study highlights the high prevalence and genotypic diversity of Campylobacter spp. isolated from organic turkey flocks. Further research is needed to assess other potential risk factors responsible for bacteria spreading in order to mitigate the spread of Campylobacter in organic turkey flocks by improving biosecurity control measures.

Genotyping and antibiotic resistance of thermophilic Campylobacter isolated from chicken and pig meat in Vietnam

BACKGROUND

Campylobacter species are recognized as the most common cause of foodborne bacterial gastroenteritis in humans. In this study nine Campylobacter strains isolated from chicken meat and pork in Hanoi, Vietnam, were characterized using molecular methods and tested for antibiotic resistance.

RESULTS

The nine isolates (eight C. jejuni and one C. coli) were identified by multiplex PCR, and tested for the presence or absence of 29 gene loci associated with virulence, lipooligosaccharide (LOS) biosynthesis and further functions. flaA typing, multilocus sequence typing and microarray assay investigation showed a high degree of genetic diversity among these isolates. In all isolates motility genes (flaA, flaB, flhA, fliM), colonization associated genes (cadF, docB), toxin production genes (cdtA, cdtB, secD, secF), and the LOS biosynthesis gene pglB were detected. Eight gene loci (fliY, virB11, Cje1278, Cj1434c, Cj1138, Cj1438c, Cj1440c, Cj1136) could not be detected by PCR. A differing presence of the gene loci ciaB (22.2 %), Cje1280 (77.8 %), docC (66.7 %), and cgtB (55.6 %) was found. iamA, cdtC, and the type 6 secretion system were present in all C. jejuni isolates but not in C. coli. flaA typing resulted in five different genotypes within C. jejuni, MLST classified the isolates into seven sequence types (ST-5155, ST-6736, ST-2837, ST-4395, ST-5799, ST-4099 and ST-860). The microarray assay analysis showed a high genetic diversity within Vietnamese Campylobacter isolates which resulted in eight different types for C. jejuni. Antibiotic susceptibility profiles showed that all isolates were sensitive to gentamicin and most isolates (88.8 %) were sensitive to chloramphenicol, erythromycin and streptomycin. Resistance rates to nalidixic acid, tetracycline and ciprofloxacin were 88.9, 77.8 and 66.7 %, respectively.

CONCLUSIONS

To the best of our knowledge, this study is the first report that shows high genetic diversity and remarkable antibiotic resistance of Campylobacter strains isolated from meat in Vietnam which can be considered of high public health significance. These preliminary data show that large scale screenings are justified to assess the relevance of Campylobacter infections on human health in Vietnam.

Antimicrobial susceptibilities of Campylobacter jejuni and Campylobacter coli recovered from organic turkey farms in Germany

The popularity of food produced from animals kept under an organic regimen has increased in recent years. In Germany, turkey meat consumption has increased. Despite several studies assessing the susceptibility of campylobacters to various antibiotics in poultry, no sufficient data exists regarding the antimicrobial resistance of campylobacters in organic-reared turkeys. This study provides information about antibiotic resistance in Campylobacter isolated from turkeys reared on organic farms in Germany. Ninety-six Campylobacter strains (41 C. jejuni and 55 C. coli) were isolated from different free-range turkey flocks. In vitro antimicrobial sensitivity testing was done using a broth microdilution test, and the presence of resistance genes to antibiotics (ciprofloxacin, tetracycline) was investigated. All Campylobacter isolates from organic turkeys (n = 96) were phenotypically sensitive to gentamicin, erythromycin, streptomycin, and chloramphenicol. In this study, the antibiotic susceptibilities of C. jejuni to ciprofloxacin, tetracycline, and naladixic acid were 56.0%, 51.3%, and 56.0%, respectively. In contrast, 44.0%, 73.0%, and 74.6% of C. coli isolates were resistant to tetracycline, ciprofloxacin, and nalidixic acid, respectively. Replacement of the Thr-86→Ile in the gyrA gene, and the presence of the tet(O) gene were the mainly identified resistance mechanisms against fluoroquinolones and tetracycline, respectively.These results also reinforce the need to develop strategies and implement specific control procedures to reduce the development of antimicrobial resistance.

Phenotypic and genotypic diversity of thermophilic Campylobacter spp. in commercial turkey flocks: a longitudinal study

Poultry are recognized as a main reservoir of Campylobacter spp. However, longitudinal studies investigating the persistence of Campylobacter on commercial meat turkeys are rare. The objectives of this study were to determine the prevalence, antimicrobial susceptibility, and persistence of genotypically related strains of Campylobacter spp. recovered from three commercial turkey farms in Ohio belonging to a single producer. Eight hundred ten samples were collected from birds aged 1 week to slaughter, consisting of 750 fecal droppings and 60 ceca at slaughter. Overall Campylobacter prevalence was 55.9%. Multiplex polymerase chain reaction (PCR) confirmed 72.3% of all isolates as C. coli, 5.3% as C. jejuni, 10.6% as both, and 11.9% as other Campylobacter spp. PCR restriction fragment length polymorphism of the flaA gene subtyping detected 70 types-62 for C. coli and 8 for C. jejuni isolates-with most (80%) of flaA-types constituting farm homogeneous groups. Multilocus sequence typing of 99 selected Campylobacter isolates resulted in 23 sequence types (STs), consisting of 8 STs for C. jejuni and 15 STs for C. coli isolates. Six novel STs-four for C. jejuni and two-for C. coli, were detected. In a subset of isolates (n=98) tested for antimicrobial resistance, the most common resistance was to tetracycline (95%), followed by azithromycin (43%), while 42% and 18% of the isolates were resistant to ciprofloxacin and erythromycin, respectively. All isolates were susceptible to florfenicol. C. coli isolates displayed a higher proportion of resistance than C. jejuni to most antimicrobials. This study highlights the high prevalence, genotypic diversity, and antimicrobial resistance of Campylobacter spp. in commercial turkey from farm to slaughter.

Determination of antimicrobial sensitivities of Campylobacter jejuni isolated from commercial turkey farms in Germany

The emergence of antimicrobial resistance among Campylobacter isolates recovered from turkeys has increased dramatically. Monitoring the progress of this resistance becomes a growing public health issue. The aim of the present study was to provide information of the current status of antibiotic resistance patterns in Campylobacter jejuni from turkeys. Seventy-six C. jejuni isolates were recovered from 67 epidemiologically unrelated meat turkey flocks in different regions of Germany in 2010 and 2011. The isolates were typed by flaA genotyping and were investigated for antimicrobial susceptibility against 12 antibiotics by using a broth microdilution test as well as testing the genetic determination of ciprofloxacin, tetracycline, and erythromycin resistance. All isolates (n = 76) were sensitive to gentamicin and chloramphenicol. The numbers of isolates that were sensitive to streptomycin, erythromycin, neomycin, and amoxicillin were 69 (90.8%), 61 (80.2%), 58 (76.4%), and 44 (57.9%), respectively. Only one isolate was sensitive to all tested antibiotics. The emergence of a high resistance rate and multidrug resistance to three or more classes of antimicrobial agents were observed. The resistance against sulphamethoxazole/trimethoprim, metronidazole, ciprofloxacin, naladixic acid, and tetracycline was 58 (76.3%), 58 (76.3%), 53 (69.7%), 51 (67.1%), and 42 (55.3%), respectively. None of the isolates was resistant to all antibiotics. Multidrug resistance to three or more classes of antimicrobial agents was found and ranged from 3.9% to 40.8%. Replacement of the Thr-86-->Ile in gyrA gene and detection of the tet(O) gene were the main resistance mechanisms for fluoroquinolones and tetracycline, respectively, while the lack of mutation in position 2074 and 2075 on the 23S rRNA gene was responsible for macrolide resistance. The phenotypic and genotypic resistance profiles were compatible in the case of ciprofloxacin and tetracycline but were not completely congruent with respect to erythromycin.

Detection of genetic diversity in Campylobacter jejuni isolated from a commercial turkey flock using flaA typing, MLST analysis and microarray assay

Campylobacter is genetically highly diverse and undergoes frequent intraspecific recombination. Turkeys have been identified as an important reservoir for Campylobacter jejuni which is of public health significance. The assessment of the genetic diversity among Campylobacter population is critical for our understanding of the epidemiology of this bacterium. The genetic profiles were different according to the molecular typing methods used. The performance of established flaA genotyping, multilocus sequencing typing (MLST) and DNA microarray assay based on the ArrayTube™ technology was evaluated using 14 Campylobacter jejuni isolated from a commercial turkey flock. The flaA typing was performed using PCR-RFLP with restriction enzymes Sau3AI, AluI, a ‘composite’ flaA analysis of AluI and Sau3AI and DdeI. The 14 isolates were differentiated into 3, 5, 7 and 9 genotypes, respectively. Entire flaA gene and short variable region (SVR) sequences were analysed. Sequencing of the entire flaA provided 11 different genotypes. flaA-SVR sequence analysis detected 8 flaA alleles and 4 flaA peptides. One new flaA allele type (528) was identified. MLST analysis represented 10 different sequence types (STs) and 5 clonal complexes (CCs). The microarray assay recognised 14 different genotypes. The discriminatory indices were 0.560, 0.802, 0.857, and 0.912 for flaA-RFLP depending on the used enzymes, 0.890 for flaA-SVR, 0.967 for entire flaA sequencing, 0.945 for MLST and 1.00 for the DNA microarray assay. The flaA gene was genetically stable over 20 passages on blood agar. In conclusion, the different typing tools demonstrated a high level of genetic heterogeneity of Campylobacter jejuni in a turkey flock, indicating that a single flock can be infected by multiple genotypes within one rearing cycle. DNA microarray-based assays had the highest discriminatory power when compared with other genotyping tools.

Zoonotic agents in small ruminants kept on city farms in southern Germany

Sheep and goats are popular examples of livestock kept on city farms. In these settings, close contacts between humans and animals frequently occur. Although it is widely accepted that small ruminants can carry numerous zoonotic agents, it is unknown which of these agents actually occur in sheep and goats on city farms in Germany. We sampled feces and nasal liquid of 48 animals (28 goats, 20 sheep) distributed in 7 city farms and on one activity playground in southern Germany. We found that 100% of the sampled sheep and 89.3% of the goats carried Shiga toxin-producing Escherichia coli (STEC). The presence of Staphylococcus spp. in 75% of both sheep and goats could be demonstrated. Campylobacter spp. were detected in 25% and 14.3% of the sheep and goats, respectively. Neither Salmonella spp. nor Coxiella burnetii was found. On the basis of these data, we propose a reasonable hygiene scheme to prevent transmission of zoonotic agents during city farm visits.