Prevalence of Campylobacter spp. in Pig Slaughtering Line in Eastern China: Analysis of Contamination Sources

First study in the frequency of isolation and phenotypic antimicrobial resistance profiles of pig and cattle origin Campylobacter strains in Romania

Campylobacter spp. is recognized as one of the most common pathogens involved in the development of gastrointestinal infections in humans. The current study aimed to enhance the knowledge on the occurrence and molecular characterization of Campylobacter spp. in pigs and cattle origin caecum samples (n = 56) collected in one year, from nine Romanian slaughterhouses, and to determine the antimicrobial resistance profile of the isolated strains. All Campylobacter spp. strains (n = 41) isolated from swine and cattle caecum samples were analyzed in terms of antimicrobial resistance, in accordance with the EURL protocol and with the Commission Implementing Decision No. 2020/1729. The prevalence rate for C. coli. in pig caecum samples was 92.3% (36/39), and the prevalence of C. jejuni, in cattle origin samples was 29.4% (5/17). C. coli strains isolated from pigs proved resistant to tetracycline 75% (27/36), ciprofloxacin 69.4% (25/36), erythromycin 8.3% (3/36), ertapenem 2.8% (1/36) and gentamicin 2.8% (1/36), but no resistance was observed towards chloramphenicol. C. jejuni strains originating from cattle expressed resistance to ciprofloxacin 60.0% (3/5) and tetracycline 20.0% (1/5), but they were susceptible to chloramphenicol, erythromycin, ertapenem and gentamicin. In the present study, 19.5% (7/36) C. coli strains isolated from pigs were identified as multidrug-resistant (MDR) bacteria. The obtained results demonstrated that pigs especially, but cattle to, can be considered important natural reservoirs for zoonotic multidrug-resistant Campylobacter strains, having a stimulating effect for further studies aiming at the molecular screening of the genotypic antimicrobial resistance processing of a higher number of samples.

Phenotypic and Genomic Characteristics of Campylobacter gastrosuis sp. nov. Isolated from the Stomachs of Pigs in Beijing

Campylobacter is among the four main causes of gastroenteritis worldwide. Most reported Campylobacter infections are caused by C. jejuni and C. coli. However, other emerging Campylobacter pathogens have been recognized as important pathogens in humans and animals. A novel bacterial strain, PS10T, was isolated from the gastric mucous of pigs in 2022 in Beijing, China. The cell was Gram-negative, microaerobic, motile, and negative for catalase, oxidase, and urease. Phylogenetic and phylogenomic analyses based on the 16S rRNA gene and core genome indicated that this isolate belongs to the genus Campylobacter. There were low dDDH relatedness and ANI values shared within this strain and its closest species C. mucosalis below the cut-off values generally recognized for isolates of the same species. The draft genome size of PS10T is 2,240,910 bp in length with a percentage of DNA G+C contents of 37.72%. Comparing the phenotypic and phylogenetic features among this isolate and its related organisms, strain PS10T represents a novel species within the genus Campylobacter, for which the name Campylobacter gastrosuis sp. nov. (Type strain PS10T = GDMCC 1.3686T = JCM 35849T) is proposed.

Porcine carcasses as an underestimated source of antimicrobial resistant Campylobacter coli

Introduction

Campylobacteriosis is the most common human foodborne bacterial infection worldwide and is caused by bacteria of the Camplylobacter genus. The main source of these bacteria is poultry, but other food-producing animals such as pigs are also responsible for human infections. An increasing number of strains with resistance to fluoroquinolones and other antimicrobials such as macrolides were recently noted. The aim of the study was to investigate Campylobacter contamination of porcine carcasses and determine the antimicrobial resistance of the obtained isolates.

Material and Methods

A total of 534 swabs from carcasses of pigs slaughtered in Poland during 2019-2022 were tested for Campylobacter spp.

Results

Campylobacter was detected in 164 (30.7%) carcasses; among them 149 (90.8%) were classified as C. coli and the remaining 15 (9.2%) samples were C. jejuni-positive. Because a low number of C. jejuni isolates were identified, only the C. coli isolates were subjected to antimicrobial resistance analysis. The majority of these isolates were resistant to streptomycin (94.0%), ciprofloxacin (65.8%) and tetracycline (65.1%). A total of 94 (63.1%) strains displayed antimicrobial multiresistance patterns and were mainly resistant to fluoroquinolones, aminoglycosides and tetracyclines (74; 49.7% of the isolates tested).

Conclusion

The obtained results showed that pig carcasses may be contaminated with antimicrobial-resistant C. coli.

Genomic Insights into the Increased Occurrence of Campylobacteriosis Caused by Antimicrobial-Resistant Campylobacter coli

Campylobacter is the leading bacterial cause of diarrheal illnesses worldwide. Campylobacter jejuni and C. coli are the most common species accounting for campylobacteriosis. Although the proportion of campylobacteriosis caused by C. coli is increasing rapidly in China, the underlying mechanisms of this emergence remain unclear. In this study, we analyzed the whole-genome sequences and associated environments of 1,195 C. coli isolates with human, poultry, or porcine origins from 1980 to 2021. C. coli isolates of human origin were closely related to those from poultry, suggesting that poultry was the main source of C. coli infection in humans. Analysis of antimicrobial resistance determinants indicated that the prevalence of multidrug-resistant C. coli has increased dramatically since the 2010s, coinciding with the shift in abundance from C. jejuni to C. coli in Chinese poultry. Compared with C. jejuni, drug-resistant C. coli strains were better adapted and showed increased proliferation in the poultry production environment, where multiple antimicrobial agents were frequently used. This study provides an empirical basis for the molecular mechanisms that have enabled C. coli to become the dominant Campylobacter species in poultry; we also emphasize the importance of poultry products as sources of campylobacteriosis caused by C. coli in human patients. IMPORTANCE The proportion of campylobacteriosis caused by C. coli is increasing rapidly in China. Coincidentally, the dominant species of Campylobacter occurring in poultry products has shifted from C. jejuni to C. coli. Here, we analyzed the whole-genome sequences of 1,195 C. coli isolates from different origins. The phylogenetic relationship among C. coli isolates suggests that poultry was the main source of C. coli infection in humans. Further analysis indicated that antimicrobial resistance in C. coli strains has increased dramatically since the 2010s, which could facilitate their adaptation in the poultry production environment, where multiple antimicrobial agents are frequently used. Thus, our findings suggest that the judicious use of antimicrobial agents could mitigate the emergence of multidrug-resistant C. coli strains and enhance clinical outcomes by restoring drug sensitivity in Campylobacter.

Occurrence of Campylobacter spp. and Phenotypic Antimicrobial Resistance Profiles of Campylobacter jejuni in Slaughtered Broiler Chickens in North-Western Romania

Campylobacteriosis is recognized as one of the most common food-borne zoonoses, with worldwide distribution, having undercooked poultry meat and other cross-contaminated foodstuffs as the main sources of human infections. The current study aimed to provide data on the occurrence of the thermophilic Campylobacter spp. in seven broiler chicken flocks, from three north-western Transylvanian counties of Romania, as well as to determine the antimicrobial resistance profile of the isolated C. jejuni strains. A total of 324 fresh cecal samples were collected during the slaughtering process, and screened for the presence of Campylobacter spp., using routine microbiological and molecular diagnostic tools. Overall, 85.2% (276/324; 95% CI 80.9-88.6) of the tested samples expressed positive results for Campylobacter spp., with dominant occurrence of C. coli towards C. jejuni (63.4% vs. 36.6%). From the six tested antimicrobials, the 101 isolated C. jejuni strains were resistant against ciprofloxacin (79.2%), nalidixic acid (78.2%), tetracycline (49.5%), and streptomycin (7.9%), but total susceptibility was noticed against erythromycin and gentamicin. Seven (6.9%) isolates exhibited multidrug resistance. The study results emphasize the role of broiler chicken as reservoir of Campylobacter infections for humans, as well as strengthen the necessity of the prudent using of antimicrobials in the poultry industry.

Surveillance and Reduction Control of Escherichia coli and Diarrheagenic E. coli During the Pig Slaughtering Process in China

The microbial contamination of pork during the slaughter process, especially that of the hygiene indicator bacteria, Escherichia coli, is closely related to the safety and quality of the meat. Some diarrheagenic E. coli can cause serious foodborne diseases, and pose a significant threat to human life and health. In order to ascertain the current status of E. coli and diarrheagenic E. coli contamination during the pig slaughter process in China, we conducted thorough monitoring of large-sized slaughterhouses, as well as small- or medium-sized slaughterhouses, in different provinces of China from 2019 to 2020. The overall positive rate of E. coli on the pork surface after slaughter was very high (97.07%). Both the amount of E. coli contamination and the positive ratio of diarrheagenic E. coli in large-sized slaughterhouses (7.50–13.33 CFU/cm², 3.44%) were lower than those in small- or medium-sized slaughterhouses (74.99–133.35 CFU/cm², 5.71%). Combined with the current status of sanitary control in slaughterhouses, we determined that pre-cooling treatment significantly reduced E. coli and diarrheagenic E. coli in pork after slaughter, while microbiological testing reduced E. coli. Based on our monitoring data, China urgently needs to establish relevant standards to better control microbial contamination during pig slaughtering progress. This study provided a theoretical basis for the hygiene quality management of the pig slaughter industry in China.

Prevalence and antimicrobial profiling of Campylobacter spp. isolated from meats, animal, and human feces in Northern of Morocco

The present work was carried out to understand the occurrence and antimicrobial susceptibility of Campylobacter spp., in various samples in Northern of Morocco. For this purpose, a random sampling was undertaken from butcher shops, traditional markets, and slaughterhouse. First, the research of Campylobacter was performed according to the Moroccan standard NM ISO: 10272-1 (2008). Second, the isolates were identified by biochemical tests and real time PCR. After the biochemical and molecular identification of suspected colonies, a disk diffusion method was executed to determine the sensitivity of Campylobacter spp. against 18 antibiotics. The results showed a moderate prevalence of Campylobacter species (130/466) recovered mainly on the Campylobacter blood base agar, where C. coli (108/130) were more prevalent comparable to C. jejuni (22/130) in poultry and cattle meat, raw milk, cloacal and surface swabs, and stool of patient suffering from diarrhea. The findings supported also the sensitivity of multiplex qPCR to detect Campylobacter strains compared to Moroccan standard NM ISO: 10272-1 (2008). Among our isolates, C. jejuni were the most susceptible strain toward colistin, florfenicol, gentamicin, streptomycin, and erythromycin. Nonetheless, the presence of multidrug Campylobacter resistant strains was highly observed in C. jejuni isolated, particularly, from broiler chickens toward the antibiotic classes of cephalosporin, penicillin, monobactam, quinolone, fluoroquinolone, sulfamide, as well as tetracycline. This may be due to common use of these drugs in veterinary medicine and farms as growth factor, which limits the usefulness of these molecules. Hence, the study highlights the importance of resistance profile monitoring of these pathogens in Northern of Morocco, in order to develop appropriate control measures and to reduce the emergence of multidrug-resistant strains.