BACKGROUND: Children with under-five year age disproportionally affected with foodborne illness. Campylobacteriosis is the most common foodborne disease next to Norovirus infection. Macrolides are commonly prescribed as the first line of treatment for Campylobacter gastroenteritis, with fluoroquinolone and tetracycline as secondary options. However, resistance to these alternatives has been reported in various regions worldwide.
OBJECTIVE: To determine the prevalence, associated risk-factors and antimicrobial resistance of Campylobacter jejuni and C. coli among under-five children with diarrhea.
METHODS: Institution-based cross-sectional study was conducted from November, 2022 to April 2023. The study sites were selected using a random sampling technique, while the study subjects were included using a convenient sampling technique. The data were collected using a structured questionnaire. Stool samples were inoculated onto modified charcoal cefoperazone deoxycholate agar and incubated for 48 hours. The suspected colonies were analyzed using matrix-assisted laser desorption ionization-time of flight mass spectrometry to confirm the species. Antimicrobial susceptibility testing was performed using a disc diffusion technique. All potential covariates (independent variables) were analyzed one by one using bivariate logistic regression model to identify candidate variables with P value < 0.25. Multivariable logistic analysis was used to identify potential associated factors using the candidate variables. A p value ≤ 0.05 at a 95% confidence interval was statistically significant.
RESULTS: Among the 428 samples, 7.0% (CI: 4.5-9.3) were confirmed Campylobacter species. The prevalence of C. jejuni and C. coli among under-five children was 5.1% (CI: 3.0-7.0) and 1.9% (CI: 0.7-3.3), respectively. C. jejuni (73.3%) was dominant over C. coli (26.7%). The resident, contact with domestic animals, and parents/guardians education level were significantly associated with campylobacteriosis among under-five children. One-third of the Campylobacter isolates (33.3%, 10/30) were resistant to ciprofloxacin and tetracycline whereas 10.0% (3/30) were resistant to erythromycin. Furthermore, 3.3% (1/30) of the Campylobacter were found to be multidrug-resistant.
CONCLUSIONS: The prevalence of Campylobacter species was 7.0%. The resistance rate of Campylobacter species of ciprofloxacin and tetracycline-resistance strains was 33.3%. Peri-urban residence, contact with domestic animals, and low parental educational statuses were significantly associated factors with increased risk of Campylobacter infection. Continuous surveillance on antimicrobial resistance and health education of personal and environmental hygiene should be implemented in the community.

Human gastrointestinal infections caused by Campylobacter species is the second most important foodborne illness after salmonellosis worldwide. Poultry represent one of the main sources of Campylobacter organisms. In the present study, the short variable region of flagellin gene (SVR-flaA) typing was carried out to determine the variation among the circulating strains of Campylobacter jejuni and Campylobacter coli. The C. jejuni and C. coli isolated from poultry and poultry meat were screened for the presence of virulence determinants like cadF, flaA, cdtB, and wlaN gene. The screening for wlaN gene is crucial in view of the fact that most patients with Guillian Barre\'s (GB) syndrome with a preceding history of diarrheal illness have been found to harbor wlaN gene-positive C jejuni strains. Out of the 200 samples comprising poultry meat and cloacal swabs, 21.5% of samples were found to harbor Campylobacter spp. of which 2.5% were Campylobacter jejuni, and 19% were confirmed as Campylobacter coli. The cadF, flaA, cdtB virulence genes were detected in all the Campylobacter spp. isolated in the present study. The presence of the wlaN gene in the Campylobacter jejuni isolated in the present study may pose a public health threat with long-term human health implications. The SVR-flaA typing of twelve Campylobacter isolates obtained in the present study revealed that Campylobacter coli flaA sequence OL471375 is a new strain with a novel allele type 1,675 and peptide sequence 5 which stands deposited in pubMLST database for Campylobacter. The other flaA-SVR gene sequences identified in this study were OL471369, OL471370, OL471371, OL471372, OL471373, and OL471374. Among twelve Campylobacter spp., three distinct DdeI-RFLP patterns were observed, each varying in size from 100 to 1,000 base pairs. Antimicrobial profiling of the Campylobacter spp. isolated in the present study revealed that 50% of the strains were multidrug resistant. All the Campylobacter spp. were resistant to ciprofloxacin (CIP), ampicillin (AMP), penicillin (PEN), and nalidixic acid (NAL) whereas 57.1% of strains were resistant to tetracycline (TET) and erythromycin (ERY) 28% to amoxicillin (AMX) and enrofloxacin (ENO), 85% to amikacin (AMK). The high degree of resistance to fluoroquinolones observed in the present study is crucial in view of fluoroquinolones being drugs of choice for the treatment of human Campylobacter infections.

Recombination of short DNA fragments via horizontal gene transfer (HGT) can introduce beneficial alleles, create genomic disharmony through negative epistasis, and create adaptive gene combinations through positive epistasis. For non-core (accessory) genes, the negative epistatic cost is likely to be minimal because the incoming genes have not co-evolved with the recipient genome and are frequently observed as tightly linked cassettes with major effects. By contrast, interspecific recombination in the core genome is expected to be rare because disruptive allelic replacement is likely to introduce negative epistasis. Why then is homologous recombination common in the core of bacterial genomes? To understand this enigma, we take advantage of an exceptional model system, the common enteric pathogens Campylobacter jejuni and C. coli that are known for very high magnitude interspecies gene flow in the core genome. As expected, HGT does indeed disrupt co-adapted allele pairings, indirect evidence of negative epistasis. However, multiple HGT events enable recovery of the genome\'s co-adaption between introgressing alleles, even in core metabolism genes (e.g., formate dehydrogenase). These findings demonstrate that, even for complex traits, genetic coalitions can be decoupled, transferred, and independently reinstated in a new genetic background-facilitating transition between fitness peaks. In this example, the two-step recombinational process is associated with C. coli that are adapted to the agricultural niche.IMPORTANCEGenetic exchange among bacteria shapes the microbial world. From the acquisition of antimicrobial resistance genes to fundamental questions about the nature of bacterial species, this powerful evolutionary force has preoccupied scientists for decades. However, the mixing of genes between species rests on a paradox: 0n one hand, promoting adaptation by conferring novel functionality; on the other, potentially introducing disharmonious gene combinations (negative epistasis) that will be selected against. Taking an interdisciplinary approach to analyze natural populations of the enteric bacteria Campylobacter, an ideal example of long-range admixture, we demonstrate that genes can independently transfer across species boundaries and rejoin in functional networks in a recipient genome. The positive impact of two-gene interactions appears to be adaptive by expanding metabolic capacity and facilitating niche shifts through interspecific hybridization. This challenges conventional ideas and highlights the possibility of multiple-step evolution of multi-gene traits by interspecific introgression.

Campylobacter spp., such as Campylobacter jejuni and Campylobacter coli, are important zoonotic Gram-negative pathogens that cause acute intestinal diseases in humans. In this study, a retrospective analysis was conducted on previously collected Campylobacter isolates from antimicrobial resistance surveillance. A total of 29 optrA-positive C. coli strains were identified and subjected to second-generation sequencing. Multilocus sequence typing and single nucleotide polymorphism analyses demonstrated that the 29 optrA-positive isolates were genetically homogeneous. Notably, among the 29 isolated strains, the ΔoptrA variants exhibit a nonsense mutation at position 979 where the base C is substituted by T, leading to the formation of a premature termination codon. The alignment of sequences and genetic environmental characteristics suggested that ΔoptrA located on a chromosomally carried multidrug-resistant genomic island. There are other resistant genes on the multidrug resistance genomic island, such as aph(2\'\')-If, aph(3\')-III, aadE, tet(O), tet(L), cat, erm(A), optrA and blaOXA-61. As a result, the 29 ΔoptrA-positive strains displayed susceptibility to both florfenicol and linezolid. The ΔoptrA gene is linked to the erm(A) gene, resulting in the formation of translocatable unit (TU) that are encompassed by two copies of IS1216 mobile elements. Multiple occurrences of similar TUs have been documented in numerous C. coli and provided evidence for the significance of TUs in facilitating the transfer of drug resistance genes in C. coli.

The spread of antimicrobial resistant Campylobacter strains, linked to antimicrobials use and abuse in humans and food animals, has become a global public health problem. In this study, we determine the prevalence of antimicrobial resistance (AMR) in human Campylobacter isolates (n = 820) collected in Piedmont, Italy, from March 2020 to July 2023. The strains underwent susceptibility testing to determine the minimal inhibitory concentration for erythromycin, ciprofloxacin, gentamicin, streptomycin, and tetracycline: 80.1% of the strains showed resistance to at least one antibiotic. The highest prevalence of AMR was noted for ciprofloxacin and tetracycline (72.1% and 52.9%, respectively) and the lowest for erythromycin and aminoglycosides (streptomycin/gentamicin) (3.2% and 5.4%, respectively). The prevalence of co-resistance against fluoroquinolones and tetracyclines was 41.1%. The prevalence of multidrug resistant strains was 5.7%. Our data support evidence that AMR in human Campylobacter strains is common, particularly against ciprofloxacin and tetracycline, two medically important antimicrobials for humans.

Campylobacter jejuni or Campylobacter coli infection can lead to post-infectious irritable bowel syndrome in humans and may produce a similar syndrome in rhesus macaques (Macaca mulatta). We report the complete genomes of 8 C. jejuni isolates and 103 C. coli isolates obtained from rhesus macaques with and without intestinal disease.

Campylobacter causes bacterial enteritis, dysentery, and growth faltering in children in low- and middle-income countries (LMICs). Campylobacter spp. are fastidious organisms, and their detection often relies on culture independent diagnostic technologies, especially in LMICs. Campylobacter jejuni and Campylobacter coli are most often the infectious agents and in high income settings together account for 95% of Campylobacter infections. Several other Campylobacter species have been detected in LMIC children at an increased prevalence relative to high income settings. After doing extensive whole genome sequencing of isolates of C. jejuni and C. coli in Peru, we observed heterogeneity in the binding sites for the main species-specific PCR assay (cadF) and designed an alternative rpsKD-based qPCR assay to detect both C. jejuni and C. coli. The rpsKD-based qPCR assay identified 23% more C.jejuni/ C.coli samples than the cadF assay among 47 Campylobacter genus positive cadF negative samples verified to have C. jejuni and or C. coli with shotgun metagenomics. This assay can be expected to be useful in diagnostic studies of enteric infectious diseases and be useful in revising the attribution estimates of Campylobacter in LMICs.

Campylobacter is one of the most common causes of foodborne gastroenteritis. The objective of this study was to estimate the prevalence and risk factors associated with Campylobacter jejuni and Campylobacter coli species in fresh chicken carcasses for human consumption from farmers\' markets and small food stores in seven localities of Bogotá, Colombia. Ninety-one samples of fresh chicken carcasses were collected from farmers\' markets and small food stores at seven localities in Bogotá. Samples were tested for Campylobacter using the real-time polymerase chain reaction (real time PCR) and isolation by plating. To analyze possible risk factors associated with Campylobacter spp. contamination in retail chicken carcasses, information was collected using a structured questionnaire and a univariate logistic regression analysis (α = 0.05) was used. Forty-two positive samples were obtained for Campylobacter spp., given a prevalence of 46.2%, of which 54.8% were to C. jejuni, 9.52% to C. coli and 35.7% to joint contaminations. C. jejuni was the most prevalent species. Risk factors found included poor cleanliness, in frequency of disinfection, type of establishment, and direct contact of chickens with other food. This study is the first report in the country on the prevalence and risk factors of Campylobacter in retail chicken.

Foodborne infections with antimicrobial-resistant Campylobacter spp. remain an important public health concern. Publicly available data collected by the National Antimicrobial Resistance Monitoring System for Enteric Bacteria related to antimicrobial resistance (AMR) in Campylobacter spp. isolated from broiler chickens and turkeys at the slaughterhouse level across the United States between 2013 and 2021 were analysed. A total of 1,899 chicken-origin (1,031 Campylobacter coli (C. coli) and 868 Campylobacter jejuni (C. jejuni)) and 798 turkey-origin (673 C. coli and 123 C. jejuni) isolates were assessed. Chicken isolates exhibited high resistance to tetracycline (43.65%), moderate resistance to ciprofloxacin (19.5%), and low resistance to clindamycin (4.32%) and azithromycin (3.84%). Turkey isolates exhibited very high resistance to tetracycline (69%) and high resistance to ciprofloxacin (39%). The probability of resistance to all tested antimicrobials, except for tetracycline, significantly decreased during the latter part of the study period. Turkey-origin Campylobacter isolates had higher odds of resistance to all antimicrobials than isolates from chickens. Compared to C. jejuni isolates, C. coli isolates had higher odds of resistance to all antimicrobials, except for ciprofloxacin. The study findings emphasize the need for poultry-type-specific strategies to address differences in AMR among Campylobacter isolates.

Chickens are the primary reservoirs of Campylobacter spp., mainly C. jejuni and C. coli, that cause human bacterial gastrointestinal infections. However, genomic characteristics and antimicrobial resistance of Campylobacter spp. in low- to middle-income countries need more comprehensive exploration. This study aimed to characterize 21 C. jejuni and 5 C. coli isolates from commercial broilers and native chickens using whole genome sequencing and compare them to 28 reference Campylobacter sequences. Among the 26 isolates, 13 sequence types (ST) were identified in C. jejuni and 5 ST in C. coli. The prominent ST was ST 2274 (5 isolates, 19.2%), followed by ST 51, 460, 2409, and 6455 (2 isolates in each ST, 7.7%), while all remaining ST (464, 536, 595, 2083, 6736, 6964, 8096, 10437, 828, 872, 900, 8237, and 13540) had 1 isolate per ST (3.8%). Six types of antimicrobial resistance genes (ant(6)-Ia, aph(3\')-III, blaOXA, cat, erm(B), and tet(O)) and one point mutations in the gyrA gene (Threonine-86-Isoleucine) and another in the rpsL gene (Lysine-43-Arginine) were detected. The blaOXA resistance gene was present in all isolates, the gyrA mutations was in 95.2% of C. jejuni and 80.0% of C. coli, and the tet(O) resistance gene in 76.2% of C. jejuni and 80.0% of C. coli. Additionally, 203 virulence-associated genes linked to 16 virulence factors were identified. In terms of phenotypic resistance, the C. jejuni isolates were all resistant to ciprofloxacin, enrofloxacin, and nalidixic acid, with lower levels of resistance to tetracycline (76.2%), tylosin (52.3%), erythromycin (23.8%), azithromycin (22.2%), and gentamicin (11.1%). Most C. coli isolates were resistant to all tested antimicrobials, while 1 C. coli was pan-susceptible except for tylosin. Single-nucleotide polymorphisms concordance varied widely, with differences of up to 13,375 single-nucleotide polymorphisms compared to the reference Campylobacter isolates, highlighting genetic divergence among comparative genomes. This study contributes to a deeper understanding of the molecular epidemiology of Campylobacter spp. in Thai chicken production systems.