refMLST: reference-based multilocus sequence typing enables universal bacterial typing.

BACKGROUND: Commonly used approaches for genomic investigation of bacterial outbreaks, including SNP and gene-by-gene approaches, are limited by the requirement for background genomes and curated allele schemes, respectively. As a result, they only work on a select subset of known organisms, and fail on novel or less studied pathogens. We introduce refMLST, a gene-by-gene approach using the reference genome of a bacterium to form a scalable, reproducible and robust method to perform outbreak investigation. RESULTS: When applied to multiple outbreak causing bacteria including 1263 Salmonella enterica, 331 Yersinia enterocolitica and 6526 Campylobacter jejuni genomes, refMLST enabled consistent clustering, improved resolution, and faster processing in comparison to commonly used tools like chewieSnake. CONCLUSIONS: refMLST is a novel multilocus sequence typing approach that is applicable to any bacterial species with a public reference genome, does not require a curated scheme, and automatically accounts for genetic recombination. AVAILABILITY AND IMPLEMENTATION: refMLST is freely available for academic use at https://bugseq.com/academic .

Burden and epidemiology of Campylobacter species in acute enteritis cases in Burkina Faso.

BACKGROUND: Campylobacter spp. is a significant etiological agent of bacterial gastroenteritis globally. In Burkina Faso (BFA), the actual impact of this pathogen on gastroenteritis is considerably underestimated, primarily due to inadequate surveillance systems. OBJECTIVES: This study aimed to investigate the proportion of Campylobacter species responsible for acute gastroenteritis among patients of all ages in urban and rural areas of BFA, using molecular biology techniques. STUDY DESIGN & METHODS: Between 2018 and 2021, faecal specimens were obtained from 1,295 individuals presenting with acute gastroenteritis. These samples underwent screening for the Campylobacter coli/jejuni/lari complex utilizing real-time polymerase chain reaction (PCR) assays. Subsequently, positive samples were subjected to species-level differentiation through the application of species-specific primers. RESULTS: Campylobacter spp. was detected in 25.0% (324/1,295) of the samples analysed. The majority of positive samples (95%, 308/324) were obtained from children under 5 years of age. Species identification was performed on a subset of 114 isolates, revealing 51 Campylobacter jejuni, 10 Campylobacter coli, and 53 Campylobacter isolates that remained unspeciated. CONCLUSIONS: This study reveals a significant prevalence of Campylobacter species among patients with acute gastroenteritis, with a particularly high incidence observed in children under 5 years of age. Based on these findings, the implementation of routine Campylobacter surveillance in public health laboratories is strongly recommended to better monitor and address this health concern.

Quadruplex qPCR for detection and discrimination of C. Coli,C. fetus, and C. Jejuni from other Campylobacter species in chicken and sheep meat.

Campylobacter is gram-negative bacteria considered the predominant genera isolated from poultry samples and associated with gastroenteritis. Due to the problems in conventional cultural methods of time-consuming and technically demanding requirements, a rapid and feasible method for their identification and discrimination of the closely related spp. Including Campylobacter coli, Campylobacter fetus, and Campylobacter jejuni is needed. This study analyzes the chicken and sheep meats samples (n = 125) using culture and pre-enrichment-based Quadraplex real-time PCR by targeting OrfA, CstA, HipO, and 16 S rRNA genes of C. coli, C. fetus, C. jejuni and Campylobacter spp. Respectively. The analysis of 125 chicken and sheep meat samples by culture and real-time PCR showed high concordance between the results of the two methods. The present study show high prevalence of Campylobacter species (35% and 32% from chicken and meat respectively) of which C. jejuni were the most abundant. Reaction efficiencies were between 90 and 110%, and detect as low as 8.9 fg in C. jejuni. The need for quick detection and discrimination methods in sheep and chicken meat can be met using the described Quadraplex real-time PCR methodology.

Five centuries of genome evolution and multi-host adaptation of Campylobacter jejuni in Brazil.

Consumption of raw, undercooked or contaminated animal food products is a frequent cause of Campylobacter jejuni infection. Brazil is the world's third largest producer and a major exporter of chicken meat, yet population-level genomic investigations of C. jejuni in the country remain scarce. Analysis of 221 C. jejuni genomes from Brazil shows that the overall core and accessory genomic features of C. jejuni are influenced by the identity of the human or animal source. Of the 60 sequence types detected, ST353 is the most prevalent and consists of samples from chicken and human sources. Notably, we identified the presence of diverse bla genes from the OXA-61 and OXA-184 families that confer beta-lactam resistance as well as the operon cmeABCR related to multidrug efflux pump, which contributes to resistance against tetracyclines, macrolides and quinolones. Based on limited data, we estimated the most recent common ancestor of ST353 to the late 1500s, coinciding with the time the Portuguese first arrived in Brazil and introduced domesticated chickens into the country. We identified at least two instances of ancestral chicken-to-human infections in ST353. The evolution of C. jejuni in Brazil was driven by the confluence of clinically relevant genetic elements, multi-host adaptation and clonal population growth that coincided with major socio-economic changes in poultry farming.

Epidemiological and molecular investigations of sequential outbreaks of Campylobacter jejuni infecting adults and schoolchildren in southeastern China, 2021-2022.

OBJECTIVES: To investigate cases of five Campylobacter jejuni outbreaks and describe laboratory characteristics of these infections. METHODS: Whole-genome sequencing and conventional methods were combined to thoroughly investigate the outbreaks, and data of contemporaneous sporadic cases was included for comparison. RESULTS: Seven sequence types (STs) of C. jejuni caused 83 cases, including ST9079 which recurred across 2 years. Trace-back investigation could not identify any food items of infection but detected identical campylobacters from food contacts. Phylogenetic analysis unveiled genetic closeness between outbreak strains and some concurrent sporadic strains, indicating local campylobacteriosis may not be wholly sporadic but rather a series of linked cases. Virulence genes disclosed species/case-specific signatures to differentiate outbreaks from truly non-outbreak strains. Resistance to fluoroquinolones and/or macrolides was prevalent (90.8%, 108/119), with a noteworthy portion exhibiting multidrug resistance (31.1%, 37/119). Five types of plasmids were harbored among outbreak isolates, of which one plasmid harboring anti-stress and resistant genes was rarely found in C. jejuni. CONCLUSIONS: This is the first reported sequential outbreak of C. jejuni in China. Our observations help to define the genomic landscape and antimicrobial resistance patterns of Campylobacter, emphasizing the need for a broader 'One Health' perspective to combat the threats posed by campylobacteriosis.

Meta-analyses of the global multilocus genotypes of the human pathogen Campylobacter jejuni.

Campylobacter infections are a leading cause of bacterial diarrheal illness worldwide, with increasing reports of outbreaks in both developing and developed countries. Most studies investigating strain genotypes and epidemiology of Campylobacter jejuni examined on a local scale. Using the archived multilocus sequence typing data at seven loci, and associated strain metadata from the PubMLST database, here we investigated the spatial and temporal genetic structure of the global population of C. jejuni. Our analyses revealed evidence for clonal dispersals of multiple sequence types (STs) among countries and continents. However, despite the observed clonal dispersal and that most genetic variations were found within individual geographic subpopulations, both the non-clone-corrected and clone-corrected samples showed evidence of significant genetic differentiation among national and continental subpopulations, with non-clone-corrected samples showing greater differentiation than clone-corrected samples. Phylogenetic incompatibility analyses provided evidence for recombination within each continental subpopulation. However, linkage disequilibrium analyses rejected the hypothesis of random recombination across the samples. Temporally, multiple STs were found to persist across four decades and the five globally most common STs showed relatively stable frequencies over the last two decades. We discussed the implications of our results to food security, disease transmission, and public health management.

Molecular and in silico typing of the lipooligosaccharide biosynthesis gene cluster in Campylobacter jejuni and Campylobacter coli.

The extensive genetic variation in the lipooligosaccharide (LOS) core biosynthesis gene cluster has led to the development of a classification system; with 8 classes (I-VIII) for Campylobacter coli (C. coli) LOS region and with 23 classes (A-W) or four groups (1-4) for Campylobacter jejuni (C. jejuni) LOS region. PCR based LOS locus type identification for C. jejuni clinical isolates from a UK hospital as well as in silico LOS locus analysis for C. jejuni and C. coli genome sequences from GenBank was carried out to determine the frequencies of various LOS genotypes in C. jejuni and C. coli. Analysis of LOS gene content in 60 clinical C. jejuni isolates and 703 C. jejuni genome sequences revealed that class B (Group 1) was the most abundant LOS class in C. jejuni. The hierarchy of C. jejuni LOS group prevalence (group 1 > group 2 > group 3 > group 4) as well as the hierarchy of the frequency of C. jejuni LOS classes present within the group 1 (B > C > A > R > M > V), group 2 (H/P > O > E > W), group 3 (F > K > S) and group 4 (G > L) was identified. In silico analysis of LOS gene content in 564 C. coli genome sequences showed class III as the most abundant LOS locus type in C. coli. In silico analysis of LOS gene content also identified three novel LOS types of C. jejuni and previously unknown LOS biosynthesis genes in C. coli LOS locus types I, II, III, V and VIII. This study provides C. jejuni and C. coli LOS loci class frequencies in a smaller collection of C. jejuni clinical isolates as well as within the larger, worldwide database of C. jejuni and C. coli.

Relationships of capsular polysaccharides belonging to Campylobacter jejuni HS1 serotype complex.

The Campylobacter jejuni capsule type HS1 complex is one of the most common serotypes identified worldwide, and consists of strains typing as HS1, HS1/44, HS44 and HS1/8. The capsule structure of the HS1 type strain was shown previously to be composed of teichoic-acid like glycerol-galactosyl phosphate repeats [4-)-α-D-Galp-(1-2)-Gro-(1-P-] with non-stoichiometric fructose branches at the C2 and C3 of Gal and non-stoichiometric methyl phosphoramidate (MeOPN) modifications on the C3 of the fructose. Here, we demonstrate that the capsule of an HS1/44 strain is identical to that of the type strain of HS1, and the capsule of HS1/8 is also identical to HS1, except for an additional site of MeOPN modification at C6 of Gal. The DNA sequence of the capsule locus of an HS44 strain included an insertion of 10 genes, and the strain expressed two capsules, one identical to the HS1 type strain, but with no fructose branches, and another composed of heptoses and MeOPN. We also characterize a HS1 capsule biosynthesis gene, HS1.08, as a fructose transferase responsible for the attachment of the ß-D-fructofuranoses residues at C2 and C3 of the Gal unit. In summary, the common component of all members of the HS1 complex is the teichoic-acid like backbone that is likely responsible for the observed sero-cross reactivity.

Genomic analysis of the diversity, antimicrobial resistance and virulence potential of clinical Campylobacter jejuni and Campylobacter coli strains from Chile.

Campylobacter jejuni and Campylobacter coli are the leading cause of human gastroenteritis in the industrialized world and an emerging threat in developing countries. The incidence of campylobacteriosis in South America is greatly underestimated, mostly due to the lack of adequate diagnostic methods. Accordingly, there is limited genomic and epidemiological data from this region. In the present study, we performed a genome-wide analysis of the genetic diversity, virulence, and antimicrobial resistance of the largest collection of clinical C. jejuni and C. coli strains from Chile available to date (n = 81), collected in 2017-2019 in Santiago, Chile. This culture collection accounts for more than one third of the available genome sequences from South American clinical strains. cgMLST analysis identified high genetic diversity as well as 13 novel STs and alleles in both C. jejuni and C. coli. Pangenome and virulome analyses showed a differential distribution of virulence factors, including both plasmid and chromosomally encoded T6SSs and T4SSs. Resistome analysis predicted widespread resistance to fluoroquinolones, but low rates of erythromycin resistance. This study provides valuable genomic and epidemiological data and highlights the need for further genomic epidemiology studies in Chile and other South American countries to better understand molecular epidemiology and antimicrobial resistance of this emerging intestinal pathogen.

High prevalence of Campylobacter jejuni CC21 and CC257 clonal complexes in children with gastroenteritis in Tehran, Iran.

BACKGROUND: Campylobacter jejuni (C. jejuni) is a leading cause of acute gastroenteritis in human worldwide. The aim of study was to assess the distribution of sialylated lipooligosaccharide (LOS) classes and capsular genotypes in C. jejuni isolated from Iranian children with gastroenteritis. Furthermore, the level of dnaK gene expression in C. jejuni strains with selected capsular genotypes and LOS classes was intended. Moreover, a comprehensive study of C. jejuni MLST-genotypes and inclusive comparison with peer sequences worldwide was intended. METHODS: Twenty clinical C. jejuni strains were isolated from fecal specimens of 280 children aged 0-5 years, suspected of bacterial gastroenteritis, which admitted to 3 children hospitals from May to October, 2018. Distribution of sialylated LOS classes and specific capsular genotypes were investigated in C. jejuni of clinical origin. The expression of dnaK in C. jejuni strains was measured by Real-Time-PCR. MLST-genotyping was performed to investigate the clonal relationship of clinical C. jejuni strains and comparison with inclusive sequences worldwide. RESULTS: C. jejuni HS23/36c was the predominant genotype (45%), followed by HS2 (20%), and HS19 and HS4 (each 10%). A total of 80% of isolates were assigned to LOS class B and C. Higher expression level of dnaK gene was detected in strains with HS23/36c, HS2 and HS4 capsular genotypes and sialylated LOS classes B or C. MLST analysis showed that isolates were highly diverse and represented 6 different sequence types (STs) and 3 clonal complexes (CCs). CC21 and CC257 were the most dominant CCs (75%) among our C. jejuni strains. No new ST and no common ST with our neighbor countries was detected. CONCLUSIONS: The C. jejuni isolates with LOS class B or C, and capsular genotypes of HS23/36, HS2, HS4 and HS19 were dominant in population under study. The CC21 and CC257 were the largest CCs among our isolates. In overall picture, CC21 and CC353 complexes were the most frequently and widely distributed clonal complexes worldwide, although members of CC353 were not detected in our isolates. This provides a universal picture of movement of dominant Campylobacter strains worldwide.

Occurrence of Campylobacter spp. in Swedish calves, common sequence types and antibiotic resistance patterns.

AIMS: Cattle are the second most important cause of human campylobacteriosis, after poultry, but there are knowledge gaps regarding Campylobacter in cattle. This study examined the occurrence of Campylobacter, the species present, sequence types and antibiotic resistance in Swedish cattle. METHODS AND RESULTS: Faeces samples collected from 154 calves on seven Swedish farms, and 69 follow-up samples from a second collection occasion, were analysed. Campylobacter were isolated from 77% of calves at the first sampling, with Campylobacter jejuni as the most frequently isolated species. Animals kept on deep straw bedding were less likely to be colonized with Campylobacter. Whole-genome sequencing of 90 C. jejuni samples resulted in 11 sequence types, among which ST-19 and ST-21 were most frequent. Antimicrobial resistance analyses showed that 46% of 142 isolates analysed were resistant to quinolones, while all isolates belonging to ST-19, ST-22 and ST-441 were resistant to ciprofloxacin and nalidixic acid. CONCLUSIONS: Campylobacter jejuni was the species most frequently isolated in calves and a strong association was found between sequence type and antimicrobial resistance pattern. SIGNIFICANCE AND IMPACT OF THE STUDY: The high proportion of calves with quinolone-resistant Campylobacter jejuni should be considered in a One Health perspective.

Prevalence, molecular typing and antimicrobial susceptibility of Campylobacter spp. isolates in northern Spain.

AIM: To analyse the prevalence, genetic diversity and antimicrobial susceptibility of Campylobacter spp. in northern Spain. METHODS AND RESULTS: Campylobacter was isolated from 139 samples of broiler meat and faecal dropping of broiler and swine with a prevalence of 35·4, 62 and 42·8%, respectively. Campylobacter jejuni (n = 55) and Campylobacter coli (n = 31) were identified by multiplex-PCR in meat, faeces and human clinical samples while Campylobacter fetus (n = 3) was exclusively detected in the latter. Fingerprinting by flaA-RFLP and PFGE revealed 68 different genotypes from the 89 isolates with a Biodiversity Simpson's index of 0·98. The 86·5% of the isolates were resistant to ciprofloxacin, 85·4% to tetracycline and 49·4% to erythromycin; only three genotypes were susceptible to the three antimicrobial drugs. Multidrug resistance was detected in the 40·7% of the isolates. CONCLUSIONS: Campylobacter remains prevalent in northern Spain with a high biodiversity degree. About 93·3% of the isolates were resistant to one or more drugs. SIGNIFICANCE AND IMPACT OF THE STUDY: Although different measures are taken to control Campylobacter, the detection of isolates resistant to the drugs used in the treatment of campylobacteriosis is still high, including different species and genotypes. This evidences the need of additional strategies against this pathogen.

Rates of fluoroquinolone resistance in domestically acquired Campylobacter jejuni are increasing in people living within a model study location in Canada.

Antimicrobial resistance was evaluated in Campylobacter jejuni isolated from 1291 diarrheic people over a 15-year period (2004-2018) in southwestern Alberta, a model location in Canada with a high rate of campylobacteriosis. The prevalence of resistance to chloramphenicol, clindamycin, erythromycin, and gentamicin was low during the examination period (≤4.8%). Resistance to tetracycline remained consistently high (41.6%-65.1%), and resistance was primarily conferred by plasmid-borne tetO (96.2%). Resistance rates to ciprofloxacin and nalidixic acid increased substantially over the examination period, with a maximal fluoroquinolone resistance (FQR) prevalence of 28.9% in 2016. The majority of C. jejuni isolates resistant to ciprofloxacin (93.9%) contained a C257T single nucleotide polymorphism within the gyrA chromosomal gene. Follow up with infected people indicated that the observed increase in FQR was primarily due to domestically acquired infections. Moreover, the majority of FQ-resistant C. jejuni subtypes (82.6%) were endemic in Canada, primarily linked to cattle and chicken reservoirs; 18.4% of FQ-resistant isolates were assigned to three subtypes, predominantly associated with cattle. Study findings indicate the need to prioritize FQR monitoring in C. jejuni infections in Canada and to elucidate the dynamics of the emergence and transmission of resistant C. jejuni strains within and from cattle and chicken reservoirs.

Genomic epidemiology of Campylobacter jejuni associated with asymptomatic pediatric infection in the Peruvian Amazon.

Campylobacter is the leading bacterial cause of gastroenteritis worldwide and its incidence is especially high in low- and middle-income countries (LMIC). Disease epidemiology in LMICs is different compared to high income countries like the USA or in Europe. Children in LMICs commonly have repeated and chronic infections even in the absence of symptoms, which can lead to deficits in early childhood development. In this study, we sequenced and characterized C. jejuni (n = 62) from a longitudinal cohort study of children under the age of 5 with and without diarrheal symptoms, and contextualized them within a global C. jejuni genome collection. Epidemiological differences in disease presentation were reflected in the genomes, specifically by the absence of some of the most common global disease-causing lineages. As in many other countries, poultry-associated strains were likely a major source of human infection but almost half of local disease cases (15 of 31) were attributable to genotypes that are rare outside of Peru. Asymptomatic infection was not limited to a single (or few) human adapted lineages but resulted from phylogenetically divergent strains suggesting an important role for host factors in the cryptic epidemiology of campylobacteriosis in LMICs.

Microbe Profile: Campylobacter jejuni - survival instincts.

Campylobacter jejuni is considered to be the most common bacterial cause of human gastroenteritis worldwide. C. jejuni can cause bloody diarrhoea, fever and abdominal pain in humans along with post-infectious sequelae such as Guillain-Barré syndrome (a paralytic autoimmune complication). C. jejuni infections can be fatal, particularly among young children. C. jejuni are distributed in most warm-blooded animals, and therefore the main route of transmission is generally foodborne, via the consumption and handling of meat products (particularly poultry). C. jejuni is microaerophilic and oxygen-sensitive, although it appears to be omnipresent in the environment, one of the many contradictions of Campylobacter.

Genotyping of Campylobacter jejuni Isolates from Poultry by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR).

Campylobacter jejuni is the leading bacterial foodborne pathogen that causes human acute gastrointestinal illness worldwide. Due to its genetic diversity, fastidious growth and sophisticated biochemical requirements, classification of Campylobacter by traditional techniques is problematic. Several molecular typing methods have been explored in this bacterium. One such method is to use clustered regularly interspaced short palindromic repeats (CRISPR). These CRISPRs consist of a direct repeat interspaced with nonrepetitive spacer sequences. In this study, we applied this genotyping method to explore the genetic diversity of C. jejuni isolated from poultry sources. Ninety-nine C. jejuni isolates from poultry environments in four different US states were used. Genomic DNA of the isolates were extracted from cultures using a commercial kit. PCR primers and conditions for CRISPR type 1 amplification were described previously. The amplicons were purified and sequenced by the Sanger dideoxy sequencing method. The direct repeats (DR) and spacers of the CRISPR sequences were identified using the CRISPRFinder. The results show there were 21% isolates no detectable, 30% isolates questionable, and 49% isolates confirmed CRISPR, respectively. The lengths of CRISPR range from 100 to 695 nucleotides. One type of DR was found in CRISPR of these isolates. The number of spacers in CRISPR ranges from 1 to 10 with various sequences. A total of 55 distinctive spacer sequences were identified in 78 isolates. Among them, 33 sequences were found unique in this study. In addition, the CRISPR genotyping had higher the Simpson's index of diversity value than that from flaA nucleotide typing. The results of our study show the CRISPR genotyping on C. jejuni may be complementary to the other genotyping methods.

MLST-based genetic relatedness of Campylobacter jejuni isolated from chickens and humans in Poland.

Campylobacter jejuni infection is one of the most frequently reported foodborne bacterial diseases worldwide. The main transmission route of these microorganisms to humans is consumption of contaminated food, especially of chicken origin. The aim of this study was to analyze the genetic relatedness of C. jejuni from chicken sources (feces, carcasses, and meat) and from humans with diarrhea as well as to subtype the isolates to gain better insight into their population structure present in Poland. C. jejuni were genotyped using multilocus sequence typing (MLST) and sequence types (STs) were assigned in the MLST database. Among 602 isolates tested, a total of 121 different STs, including 70 (57.9%) unique to the isolates' origin, and 32 STs that were not present in the MLST database were identified. The most prevalent STs were ST464 and ST257, with 58 (9.6%) and 52 (8.6%) C. jejuni isolates, respectively. Isolates with some STs (464, 6411, 257, 50) were shown to be common in chickens, whereas others (e.g. ST21 and ST572) were more often identified among human C. jejuni. It was shown that of 47 human sequence types, 26 STs (106 isolates), 23 STs (102 isolates), and 29 STs (100 isolates) were also identified in chicken feces, meat, and carcasses, respectively. These results, together with the high and similar proportional similarity indexes (PSI) calculated for C. jejuni isolated from patients and chickens, may suggest that human campylobacteriosis was associated with contaminated chicken meat or meat products or other kinds of food cross-contaminated with campylobacters of chicken origin. The frequency of various sequence types identified in the present study generally reflects of the prevalence of STs in other countries which may suggest that C. jejuni with some STs have a global distribution, while other genotypes may be more restricted to certain countries.

Diversification of Campylobacter jejuni Flagellar C-Ring Composition Impacts Its Structure and Function in Motility, Flagellar Assembly, and Cellular Processes.

Bacterial flagella are reversible rotary motors that rotate external filaments for bacterial propulsion. Some flagellar motors have diversified by recruiting additional components that influence torque and rotation, but little is known about the possible diversification and evolution of core motor components. The mechanistic core of flagella is the cytoplasmic C ring, which functions as a rotor, directional switch, and assembly platform for the flagellar type III secretion system (fT3SS) ATPase. The C ring is composed of a ring of FliG proteins and a helical ring of surface presentation of antigen (SPOA) domains from the switch proteins FliM and one of two usually mutually exclusive paralogs, FliN or FliY. We investigated the composition, architecture, and function of the C ring of Campylobacter jejuni, which encodes FliG, FliM, and both FliY and FliN by a variety of interrogative approaches. We discovered a diversified C. jejuni C ring containing FliG, FliM, and both FliY, which functions as a classical FliN-like protein for flagellar assembly, and FliN, which has neofunctionalized into a structural role. Specific protein interactions drive the formation of a more complex heterooligomeric C. jejuni C-ring structure. We discovered that this complex C ring has additional cellular functions in polarly localizing FlhG for numerical regulation of flagellar biogenesis and spatial regulation of division. Furthermore, mutation of the C. jejuni C ring revealed a T3SS that was less dependent on its ATPase complex for assembly than were other systems. Our results highlight considerable evolved flagellar diversity that impacts motor output, biogenesis, and cellular processes in different species.IMPORTANCE The conserved core of bacterial flagellar motors reflects a shared evolutionary history that preserves the mechanisms essential for flagellar assembly, rotation, and directional switching. In this work, we describe an expanded and diversified set of core components in the Campylobacter jejuni flagellar C ring, the mechanistic core of the motor. Our work provides insight into how usually conserved core components may have diversified by gene duplication, enabling a division of labor of the ancestral protein between the two new proteins, acquisition of new roles in flagellar assembly and motility, and expansion of the function of the flagellum beyond motility, including spatial regulation of cell division and numerical control of flagellar biogenesis in C. jejuni Our results highlight that relatively small changes, such as gene duplications, can have substantial ramifications on the cellular roles of a molecular machine.

Laboratory Study on the Gastroenteritis Outbreak Caused by a Multidrug-Resistant Campylobacter coli in China.

Three severe acute gastroenteritis patients were identified within a 5-h period in a sentinel hospital enrolled in the foodborne pathogen surveillance project in Beijing. All patients had high fever (over 38.5°C), diarrhea, abdominal pain, vomiting, and headache. Ten grams of fresh patient stool sample and 25 g of six suspected foods were collected for real-time PCR screening for 10 major pathogens. Bacterial isolation was performed. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and antibiotic susceptibility tests were conducted for all the isolates. Whole-genome sequences of the three Campylobacter coli isolates were compared using whole-genome MLST. All stool samples were positive for C. coli, as revealed by PCR. Eleven of the C. coli isolates had the same PFGE and ST type. All isolates were resistant to nalidixic acid, ciprofloxacin, streptomycin, and tetracycline, consistent with the findings of the in silico antibiotic resistance gene profiling. Most coding sequences (99%, 1736/1739) were identical among the three sequenced isolates, except for three frameshift-mutated genes caused by the simple sequence repeats (poly-Gs). This was likely a single-source outbreak caused by a group of highly clonal C. coli. This was the first outbreak of severe gastroenteritis caused by C. coli in China.

Transmission of multidrug-resistant Campylobacter jejuni to children from different sources in Pakistan.

OBJECTIVES: Due to the rapid emergence of multidrug-resistant isolates, Campylobacter jejuni (C. jejuni) has been classified as a member of the priority pathogens group. This study aimed to determine the prevalence, antibiotic resistance patterns and source tracking of clinical C. jejuni isolates from paediatric diarrhoeal patients in Pakistan. METHODS: A total of 150 stool samples from children were processed for the presence of C. jejuni using culture, biochemical tests and species-specific PCR. Antibiotic susceptibility of the isolates was determined by the disc diffusion method, and metallo-ß-lactamase (MBL) producers were detected using gene-specific PCR. Source tracking was performed using source-predictive PCR. RESULTS: C. jejuni was present in 54.6% of the processed samples. More than 80% of the isolated strains were resistant to seven of 12 tested antibiotics. High levels of susceptibility were observed against imipenem (12.2%) and TGC (9.7%). Six isolates (7.3%) were MBL producers and positive for at least one of the five MBL genes. Source tracking showed that 57.3% of the isolates belonged to livestock-associated clusters (C1-C6) and 42.8% were assigned to non-livestock/environmental clusters (C7-C9). Isolates belonging to livestock clusters had a high Multiple Antibiotic Resistance (MAR) index (P < 0.001) as compared with non-livestock. CONCLUSION: A high prevalence of multidrug-resistant C. jejuni among paediatric diarrhoeal patients was observed. Moreover, the association of these isolates to livestock clades suggests transmission to human populations via the food chain. The presence of imipenem-resistant MBL-producing C. jejuni can lead to serious public health concerns.