Epidemiology of Campylobacter Infections among Children in Egypt

Campylobacter jejuni and Campylobacter coli infection, determinants and antimicrobial resistance patterns among under-five children with diarrhea in Amhara National Regional State, Northwest Ethiopia

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.

RESULT

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.

CONCLUSION

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.

Prevalence and Antimicrobial Resistance of Campylobacter Species and Associated Factors Among Under-Five Children with Diarrhea at Randomly Selected Public Health Facilities in Mekelle, Tigray, Ethiopia

Background

Campylobacter species are the most predominant bacterial agents to cause diarrhea in under-five children. It poses a serious challenge to public health worldwide with ongoing acquisition of resistance to different antimicrobials with multiple patterns. Thus, this study aimed to determine the prevalence, and antimicrobial resistance of Campylobacter species, and associated factors among under-five children with diarrhea in selected public health facilities.

Methods

A cross-sectional study was conducted among under-five children with diarrhea using convenient sampling. Health facilities were selected using a simple random sampling method. The stool samples collected from 214 study participants were transported and processed following standard microbiological protocols. Campylobacter isolates were identified using Gram staining, biochemical test, serological test, and aerobic growth at 25°C. Antimicrobial susceptibility profiles of isolates were performed using the Kirby-Bauer method. Data were analyzed using SPSS ver. 25.0. Association between variables was assessed using Chi-square test and Logistic regression, with P ≤ 0.05.

Results

The subject's mean age was 31.3 (±3.9) months. Of the 214 samples cultured, 14 (6.5%) of them were positive for Campylobacter species with 95% CI (3.3-10.3). Out of the isolated species, 12 (85.7%) were Campylobacter jejuni /Campylobacter coli and 2 (14.3%) were other Campylobacter species. Bottle feeding and history of direct contact to domestic animals were associated with Campylobacter species (AOR=5.13, CI=1.21-21.6, p=0.026 and AOR=4.93, CI=1.33-18.17, P=0.016), respectively. Campylobacter isolates were highly resistant to ciprofloxacin 5 (35.7%), and tetracycline 3 (21.4%).

Conclusion

A higher incidence of Campylobacter species was obtained in children who were bottle-fed and who had a history of direct contact with domestic animals. The isolates were highly resistant to ciprofloxacin and tetracycline. These findings indicate that special attention is needed for better management of Campylobacter drug resistance in under-five children. To enhance and support our current findings, further research using molecular techniques is needed to identify the resistant and virulent genes of the bacterial isolates.

Clinical manifestations and risk factors of campylobacter gastroenteritis in children in Taiwan

BACKGROUND

Campylobacteriosis is a common cause of bacterial gastroenteritis worldwide. This study aimed to investigate the potential risk factors, clinical and laboratory manifestations of children with campylobacteriosis under five years old in Taiwan.

METHODS

This retrospective case-control study was conducted in ten major hospitals in Taiwan from 2014 to 2017. Laboratory tests and stool specimen were collected and analyzed together with questionnaire survey. Multivariate stepwise logistic regression model was used for identification of risk factors.

RESULTS

A total of 64 campylobacteriosis cases were included with a median age of 25 months. We observed a less prolonged vomiting (p = 0.047), more bloody (p < 0.001) and mucoid (p = 0.005) stools, and lower AST levels (p = 0.020) in patients with campylobacteriosis. Lower parental educational attainment (p < 0.001), direct contact with acute gastroenteritis patients (p < 0.001), as well as diarrhea in the mutually cared children (p = 0.007) were linked to campylobacteriosis. Consumption of municipal water (p < 0.001), milk (OR 0.34, 95% CI 0.118-0.979), and soft beverages (OR 0.41, 95% CI 0.192-0.888) were identified as protective factors, while consuming takeout food (p = 0.032) and seafood (p = 0.019) increased risk of campylobacteriosis.

CONCLUSIONS

Shorter vomiting duration, bloody and mucoid stool, and less elevated AST levels are manifestations suggestive of campylobacteriosis. Risk factors of campylobacteriosis were low parental educational attainment, direct contact with acute gastroenteritis patients, diarrhea in mutually cared children, takeout food and seafood intake. Potential protective factors include municipal water, milk, and soft beverage intake.

Circulation of thermophilic Campylobacter in pigeons, turkeys, and humans at live bird markets in Egypt

Live bird markets increase the risk of transmission of zoonotic diseases. Few studies have investigated the potential zoonotic transmission of Campylobacter in Egypt. Therefore, our study was carried out to investigate the presence of Campylobacter species, mainly Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli), in pigeons and turkeys sold at poultry shops. Furthermore, the study aimed to explore the potential occupational risk of Campylobacter infection, mainly among workers at poultry shops. Six hundred (n = 600) samples from various organs were obtained from pigeons and turkeys from live bird shops in the Giza and Asyut provinces in Egypt. Additionally, 100 stool samples were collected from persons working at poultry shops. Circulation of thermophilic Campylobacter in pigeons, turkeys, and humans was investigated based on culture and molecular methods. The rate of detection of Campylobacter species from the samples was significant when the culture method was used alone in comparison to when it was used in combination with mPCR. The prevalence rates of Campylobacter species detected by mPCR were 36% (C. jejuni 20%; C. coli 16%), 28% (C. jejuni 12%; C. coli16%), and 29% (C. jejuni 15%; C. coli 14%) in pigeons, turkeys, and workers, respectively. In pigeons, significant variations in the C. jejuni and C. coli occurrence rates were reported in terms of the intestinal content (15, 4%), liver (4, 13%), and skin (9, 7%), respectively. In turkeys, Campylobacter species were mostly detected in liver samples with a percentage of 19%, followed by the skin (12%), and the intestinal content (8%). In conclusion, Campylobacter species are circulating in poultry farms in Egypt and could represent a hazard for humans. It is recommended that biosecurity measures should be applied to mitigate the occurrence of Campylobacter in poultry farms. Moreover, there is an urgent need to transform live bird markets into chilled poultry markets.

Antibiotic-resistant Campylobacter coli and Campylobacter jejuni in commercial and smallholder farm animals in the Asante Akim North Municipality of Ghana

Worldwide, farm animals, in particular poultry, are an important reservoir for Campylobacter spp. However, information on Campylobacter colonization in farm animals in Africa is scarce. Hence, this cross-sectional study determined antibiotic-resistant Campylobacter from both commercial and smallholder farm animals in the Asante Akim North Municipality of Ghana. Fecal samples from poultry and livestock kept by commercial and smallholder farms were collected and analyzed using standard microbiological methods. The overall Campylobacter frequency was 20.3% (n/N = 322/1,585), and frequencies detected were similarly high in isolates from commercial (21.0%, n/N = 169/805) and smallholder (19.6%, n/N = 153/780) farms. Species isolated were C. coli (67.7%, n/N = 218/322) and C. jejuni (32.3%, n/N = 104/322). However, the frequency of C. coli was 2.1 (95% CI: 1.8-2.5) times higher than what was found for C. jejuni. Campylobacter frequencies in the rainy season was 22.2% (n/N = 258/1,160) and 15.1% (n/N = 64/425) in the dry season (prevalence ratio = 1.48, 95% CI: 1.2-1.9). About 1.7% (n/N = 6/322) of the Campylobacter isolates, all from smallholder farms, were susceptible to all antibiotics tested. Multidrug resistance was observed for 4.7% (n/N = 15/322) of the Campylobacter isolates, of which 93.3% (n/N = 14/15) occurred in isolates from commercial farms. This study highlights the need for the implementation of control programs, in commercial farming but also at the smallholder farm level, to formulate clear guidelines aimed at decreasing Campylobacter contamination of meat products and reducing the use of antibiotics in the farming sector.

High rates of macrolide and fluoroquinolone resistance in human campylobacteriosis in the Middle East and North Africa

Campylobacter is one of the main causative agents of bacterial gastrointestinal infections. Recently, a rise in the incidence of campylobacteriosis has been reported worldwide. Despite the clinical importance of this zoonotic disease, its microbiological diagnosis is not systematically performed in clinical laboratories in developing countries such as the Middle East and North Africa region. Multidrug-resistant Campylobacter isolates, particularly against erythromycin and ciprofloxacin, have been highly reported. The findings of this study highlight the critical need to urge clinical laboratories in the Middle East and North Africa region to include screening for Campylobacter in the routine stool culture of diarrheal patients. Although there is a paucity of data regarding the epidemiology of human campylobacteriosis, alarming rates of infection prevalence and antimicrobial resistance were found in Egypt, Iran, Qatar and Lebanon.

Campylobacter Gastroenteritis Among Under-Five Children in Southwest Ethiopia

Background

Under-five children are at an increased risk for foodborne illnesses because of the ingenuousness of their immune system. Although Campylobacter species are one of the bacterial etiologies of gastroenteritis, Campylobacter gastroenteritis among under-five children is not well considered in Ethiopia. Therefore, this study aimed at exploring the prevalence, associated risk factors, and antibiotic susceptibility patterns of Campylobacter species among under-five children with diarrhea.

Methods

The institution-based cross-sectional study was conducted among under-five children with diarrhea at Jimma Medical Center, southwestern Ethiopia from January 5 to April 21, 2020. Stool samples were collected and inoculated into Campylobacter agar medium. Isolation and identification were done using standard bacteriological techniques. Antibiotic susceptibility testing was conducted on Mueller-Hinton agar supplemented with 10% sheep blood using disk diffusion techniques. Bivariate and multivariate logistic regressions were used to assess the associated risk factors.

Results

A total of 214 under-five children were enrolled. The prevalence of Campylobacter infection was 8.9%. Absence of caretakers' handwashing before preparation of food [AOR = 3.7, 95% CI: (1.2-10.8)], direct contact with domestic animals [AOR = 3.6, 95% CI: (1.0-12.7)], and consumption of raw dairy products [AOR = 4.5, 95% CI: (1.4-13.9)] are the factors associated with Campylobacter infection. Some Campylobacter species were found to be resistant to most available antibiotics.

Conclusion

The magnitude of Campylobacter gastroenteritis indicates the need for routine isolation and identification of Campylobacter species from all under-five children clinically diagnosed with diarrhea. Species that are resistant to the drug of choice for Campylobacteriosis are also emerging. Health education on the importance of pasteurization of milk and caretakers' handwashing can mitigate the transmission. Mechanism of handling of domestic animals should be considered to reduce transmission of zoonotic diseases like Campylobacteriosis.

Local accessory gene sharing among Egyptian Campylobacter potentially promotes the spread of antimicrobial resistance

Campylobacter is the most common cause of bacterial gastroenteritis worldwide, and diarrhoeal disease is a major cause of child morbidity, growth faltering and mortality in low- and middle-income countries. Despite evidence of high incidence and differences in disease epidemiology, there is limited genomic data from studies in developing countries. In this study, we aimed to quantify the extent of gene sharing in local and global populations. We characterized the genetic diversity and accessory-genome content of a collection of Campylobacter isolates from the Cairo metropolitan area, Egypt. In total, 112 Campylobacter isolates were collected from broiler carcasses (n=31), milk and dairy products (n=24), and patients suffering from gastroenteritis (n=57). Among the most common sequence types (STs), we identified the globally disseminated host generalist ST-21 clonal complex (CC21) and the poultry specialists CC206, CC464 and CC48. Notably, CC45 and the cattle-specialist CC42 were under-represented, with a total absence of CC61. Core- and accessory-genome sharing was compared among isolates from Egypt and a comparable collection from the UK (Oxford). Lineage-specific accessory-genome sharing was significantly higher among isolates from the same country, particularly CC21, which demonstrated greater local geographical clustering. In contrast, no geographical clustering was noted in either the core or accessory genome of CC828, suggesting a highly admixed population. A greater proportion of Campylobacter coli isolates were multidrug resistant compared to Campylobacter jejuni. Our results suggest that there is more horizontal transfer of accessory genes between strains in Egypt. This has strong implications for controlling the spread of antimicrobial resistance among this important pathogen.

Virulence factors of foodborne pathogen Campylobacterjejuni

Campylobacter jejuni is a highly frequent cause of gastrointestinal foodborne disease in humans throughout the world. Disease outcomes vary from mild to severe diarrhea, and in rare cases the Guillain-Barré syndrome or reactive arthritis can develop as a post-infection complication. Transmission to humans usually occurs via the consumption of a range of foods, especially those associated with the consumption of raw or undercooked poultry meat, unpasteurized milk, and water-based environmental sources. When associated to food or water ingestion, the C. jejuni enters the human host intestine via the oral route and colonizes the distal ileum and colon. When it adheres and colonizes the intestinal cell surfaces, the C. jejuni is expected to express several putative virulence factors, which cause damage to the intestine either directly, by cell invasion and/or production of toxin(s), or indirectly, by triggering inflammatory responses. This review article highlights various C. jejuni characteristics - such as motility and chemotaxis - that contribute to the biological fitness of the pathogen, as well as factors involved in human host cell adhesion and invasion, and their potential role in the development of the disease. We have analyzed and critically discussed nearly 180 scientific articles covering the latest improvements in the field.

Characterization of Campylobacter jejuni isolated from dogs and humans using flaA-SVR fragment sequencing in Ismailia, Egypt

INTRODUCTION

Dogs are known as asymptomatic carriers forCampylobacter jejuni. The number of pet dogs is increasing in Egypt in the last decade.

OBJECTIVE

This study aimed to investigate the frequency ofC. jejuni infection in dogs and humans, molecular typing of associated virulence genes, and flaA-SVR gene using sequencing.

METHODOLOGY

152 unpaired fecal swabs from dogs (n = 72) and humans (80) were examined for the presence of C. jejuni and Campylobacter 23S rRNA, and the pathogenicity genes including mapA genes, virB11, flaA, wlaN, iam, tetO, and aadA genes. Sequencing of the flaA- amplicon was also performed for the representative isolates.

RESULTS

The isolation rate ofC. jejuni was 20.8 % and 31.2 %, respectively in dogs and humans, and all isolates were tested positive for 23S rRNA and mapA genes. C. jejuni harbor virB11 and wlaN (20 %, 0%), iam (10 %, 20 %), tetO and aadA1 (40 %, both), and flaA (40 %, 20 %) in human and dog strains, respectively. The flaA-SVR sequences revealed high identity between human and dog isolates (94.8 %), but revealed 18 substitutions in the amino acid sequence, and showed that the dog and human C. jejuni were close to strains isolated from human and poultry sources.

CONCLUSION

this study demonstrated the comparative sequence analysis ofC. jejuni flaA-SVR fragment in dogs and some Egyptians, which indicated a high identity percentage between them. The results suggest that C. jejuni reservoirs dogs is an alarming public health concern and effective hygienic measures are necessary for house-holding pets to prevent C. jejuni zoonosis in Egypt's community.

Progress toward the Development of Glycan-Based Vaccines against Campylobacteriosis

As one of the main causes of bacterial diarrhea and a major risk factor for triggering Guillain-Barré autoimmune syndrome, campylobacteriosis, that is, Campylobacter spp. infections, represents a major health issue worldwide. There is thus a pressing need for developing an effective and broad-coverage campylobacteriosis vaccine. Campylobacter jejuni, an encapsulated, multidrug resistant Gram-negative bacterium, expresses virulence-associated capsular polysaccharides (CPSs), which constitute exquisite targets for the design of glycoconjugate vaccines. In that context, synthetic carbohydrate chemistry acts as a crucial enabling technology for the preparation of homogeneous constructs while allowing antigenic epitopes to be deciphered and probed at the molecular level. This review aims at covering recent developments in CPS-based campylobacteriosis vaccines as well as in the total syntheses of C. jejuni-related mono- and oligosaccharide mimics.

A systematic review and meta-analysis of Penner serotype prevalence of Campylobacter jejuni in low- and middle-income countries

Introduction

While Campylobacter jejuni is a leading foodborne bacterial pathogen worldwide, it poses a particular risk to susceptible populations in low- and middle-income countries (LMICs). A capsule-conjugate vaccine approach has been proposed as a potential solution, but little information exists on circulating C. jejuni capsule types in LMICs. The capsule is the major serodeterminant of the Penner typing scheme, which is based on serum recognition of Campylobacter heat-stable antigens. We conducted a systematic review and meta-analysis to estimate the distribution of Penner serotypes associated with C. jejuni enteritis in LMICs. Vaccine coverage assessments for hypothetical regional and global C. jejuni vaccines were also estimated.

Methods

A systematic review of the literature published from 1980 to 2019 was performed using PubMed, Scopus, and Web of Science databases. Articles were assessed for eligibility and data were abstracted. Pooled C. jejuni serotype prevalence in LMICs was estimated by region and globally using random-effects models.

Results

A total of 36 studies were included, capturing 4,434 isolates from LMICs. Fifteen serotypes were present in a sufficient number of studies to be included in analyses. Among these, HS4c was the most common serotype globally (12.6%), though leading capsule types varied among regions. HS2, HS3c, HS4c, HS5/31, HS8/17, and HS10 were all among the 10 most common region-specific serotypes.

Conclusions

The results of this review suggest that an octavalent vaccine could provide up to 66.9% coverage of typable strains worldwide, and 56.8–69.0% regionally. This review also highlights the paucity of available data on capsules in LMICs; more testing is needed to inform vaccine development efforts.

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 β-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.

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.

Stress resistance associated with multi-host transmission and enhanced biofilm formation at 42 °C among hyper-aerotolerant generalist Campylobacter jejuni

One of the emerging conundrums of Campylobacter food-borne illness is the bacterial ability to survive stressful environmental conditions. We evaluated the heterogeneity among 90 C. jejuni and 21 C. coli isolates from different sources in Egypt with respect to biofilm formation capabilities (under microaerobic and aerobic atmosphere) and resistance to a range of stressors encountered along the food chain (aerobic stress, refrigeration, freeze-thaw, heat, peracetic acid, and osmotic stress). High prevalence (63%) of hyper-aerotolerant (HAT) isolates was observed, exhibiting also a significantly high tolerance to heat, osmotic stress, refrigeration, and freeze-thaw stress, coupled with high biofilm formation ability which was clearly enhanced under aerobic conditions, suggesting a potential link between stress adaptation and biofilm formation. Most HAT multi-stress resistant and strong biofilm producing C. jejuni isolates belonged to host generalist clonal complexes (ST-21, ST-45, ST-48 and ST-206). These findings highlight the potential role of oxidative stress response systems in providing cross-protection (resistance to other multiple stress conditions) and enhancing biofilm formation in Campylobacter and suggest that selective pressures encountered in hostile environments have shaped the epidemiology of C. jejuni in Egypt by selecting the transmission of highly adapted isolates, thus promoting the colonization of multiple host species by important disease-causing lineages.

Prevalence, molecular detection, and virulence gene profiles of Campylobacter species in humans and foods of animal origin

BACKGROUND AND AIM

Campylobacteriosis is one of the most well-characterized bacterial foodborne infections worldwide that arise chiefly due to the consumption of foods of animal origin such as poultry, milk, and their products. The disease is caused by numerous species within the genus Campylobacter, but Campylobacter jejuni is the most commonly isolated species from established cases of human campylobacteriosis. This study was conducted to determine the prevalence and virulence of Campylobacter isolates from human, chicken, and milk and milk products in Egypt.

MATERIALS AND METHODS

A total of 1299 samples (547 chicken intestine and liver, 647 milk and milk products, and 105 human stool) were collected and microbiologically investigated, confirmed by multiplex polymerase chain reaction (PCR) targeting the 23S rRNA, hipO, and glyA genes specific for Campylobacter spp., C. jejuni, and Campylobacter Coli, respectively, followed by virulence genes (Campylobacter adhesion to fibronectin F [cadF] and cdtB) detection using PCR.

RESULTS

About 38.09%, 37.84%, and 8.5% of human stool, chicken, and milk and milk product samples, respectively, were bacteriologically positive, with a total of 302 Campylobacter isolates. All isolates were molecularly confirmed as Campylobacter spp. (100%) where 285 isolates (94.37%) were identified as C. jejuni and 17 isolates (5.62%) as C. coli. Regarding the virulence pattern, all isolates (100%) carried cadF gene while cytolethal distending toxin B gene was definite in 284/302 isolates (94%), concisely, 282/285 (98.94%) C. jejuni isolates, and in 2/17 (11.76%) C. coli isolates.

CONCLUSION

The widespread presence of these highly virulent Campylobacter, especially C. jejuni, proofs the urgent need for the implementation of stringent control, public health, and food protection strategies to protect consumers from this zoonotic pathogen. The availability of information about pathogen virulence will enable enhanced local policy drafting by food safety and public health officials.

Vaccine-mediated protection against Campylobacter-associated enteric disease

Campylobacter coli and Campylobacter jejuni are responsible for 400 million to 500 million cases of enteric disease each year and represent the most common cause of bacterial gastroenteritis worldwide. Despite its global importance, Campylobacter vaccine development has been hampered by the lack of animal models that recapitulate human disease pathogenesis. Here, we describe a naturally occurring Campylobacter-associated diarrhea model in outdoor-housed rhesus macaques. Using this model, we developed novel next-generation H2O2-based Campylobacter vaccines that induced strong antibacterial antibodies to multiple Campylobacter proteins including flagellin and provided up to 83% protection against severe C. coli-associated diarrhea. Whole-genome sequencing of circulating Campylobacter strains revealed little to no homology within lipooligosaccharide or capsular polysaccharide loci with the Campylobacter vaccine strains used in these studies, indicating that vaccine-mediated immunity was not restricted to a single homologous serotype. Together, these results demonstrate an important advance in vaccine development and a new approach to reducing Campylobacter-associated enteric disease.

Distribution of genes related to Type 6 secretion system and lipooligosaccharide that induced ganglioside mimicry among Campylobacter jejuni isolated from human diarrhea in Thailand

Background

Campylobacter jejuni (C. jejuni) is one of the most common bacteria responsible for human gastroenteritis worldwide. The mode of human transmission is foodborne infections due to consumption of contaminated food, especially poultry. Type 6 secretion systems (T6SS) were described recently as Campylobacter virulence mechanisms. Furthermore, infection sequelae associated with neurological disorders like Guillain-Barré (GBS) and Miller Fisher (MF) syndromes can become serious health problems in some patients after Campylobacter gastroenteritis. Our objective was to determine the distribution of these virulence genes among C. jejuni isolated from stool of human diarrhea.

Methods

A total of 524 C. jejuni strains from travelers and pediatric cases of acute diarrhea in Thailand were selected for this study. All isolates belonged to one of 20 known capsule types and all were assayed by PCR for T6SS, a hemolysin co-regulated protein (hcp) gene, and GBS-associated genes (cgtA, cgtB, cstII _HS19 and cstII _HS2 ) which are involved in sialic acid production in the lipooligosaccharide (LOS) cores of C. jejuni. The distribution of these genes are summarized and discussed.

Results

Of all isolates with these 20 capsule types identified, 328 (62.6%) were positive for hcp, ranging from 29.2 to 100% among 10 capsule types. The GBS-associated LOS genes were detected among 14 capsule type isolates with 24.4% and 23.3% of C. jejuni isolates possessed either cstII _HS19 or all three genes (cgtA, cgtB and cstII _HS19 ), which were classified as LOS classes A and B whereas 9.2% of C. jejuni isolates possessing cstII _HS2 were classified as LOS class C. The C. jejuni isolates of LOS A, B, and C together accounted for 56.9% of the isolates among 14 different capsule types while 31.1% of all C. jejuni isolates did not possess any GBS-associated genes. No significant difference was detected from C. jejuni isolates possessing GBS-associated LOS genes among travelers and children, but changes between those with hcp were significant (p < 0.05).

Conclusions

Our results suggested a high diversity of hcp and GBS-associated LOS genes among capsule types of C. jejuni isolated from Thailand.

Distribution of Capsular Types of Campylobacter jejuni Isolates from Symptomatic and Asymptomatic Children in Peru

Campylobacter jejuni is the leading bacterial cause of diarrhea worldwide. A capsular polysaccharide (CPS) conjugate vaccine is under development and requires determination of the valency. However, distribution of CPS types circulating globally is presently poorly described. We aimed to determine whether CPS type distribution in Peru differs from that in other endemic regions. We used a multiplex polymerase chain reaction (PCR) assay for the detection of CPS encoding genes capable of distinguishing all 35 CPS types on Campylobacter isolates in two prospective communities based studies conducted in cohorts of children less than 59 months of age in Peru. Results showed that CPS type HS4 complex was the most prevalent, followed by HS3 complex and HS15. Differences in CPS type for symptomatology were not statistically significant. Most subjects demonstrated repeated infections over time with different CPS types, suggesting that CPS types may confer of a level of homologous protective immunity. In this dataset, some differences in CPS type distribution were observed in comparison to other low-middle income countries. Further studies need to be conducted in endemic areas to increase our knowledge of CPS type distribution and guide vaccine development.

Genetic Diversity of Campylobacter jejuni Isolated From Avian and Human Sources in Egypt

Campylobacter jejuni (C. jejuni) are able to colonise and infect domestic poultry and also pose a risk for humans. The aim of this study was to determine the extent of genotypic diversity among C. jejuni isolates recovered from avian and human sources in Egypt. Furthermore, the short variable region (SVR) of flagellin A (flaA) gene was analysed for the presence of allelic variants. Our results showed that C. jejuni isolates differ in their capacity to harbour each of the virulence genes alone or when present in various combinations. The flaA gene was detected in all C. jejuni strains and none of the strains had all the studied virulence genes together. When considering C. jejuni strains from the investigated sources, the cdtC gene was the most similar, while the cdtB and iam genes were the most dissimilar. We could identify 13 novel alleles in the analysed strains. The analyses of virulence gene patterns, flaA gene sequences and allelic variants showed that C. jejuni strains from different sources overlapped largely suggesting potential involvement of poultry in transmitting C. jejuni to humans. We also found that the strains isolated from the same host were highly heterogeneous, with chicken strains exhibiting the highest diversity. Moreover, the human strains were clustered closer to chicken ones than to those from pigeon. The results of this study should be taken into consideration when assessing the epidemiology and risk potential of Egyptian C. jejuni not only in poultry, but also in humans.

Campylobacter at the Human-Food Interface: The African Perspective

The foodborne pathogen Campylobacter is a major cause of human gastroenteritis, accounting for an estimated annual 96 million cases worldwide. Assessment of the true burden of Campylobacter in the African context is handicapped by the under-reporting of diarrhoeal incidents and ineffective monitoring and surveillance programmes of foodborne illnesses, as well as the minimal attention given to Campylobacter as a causative agent of diarrhoea. The present review of the literature highlights the variability in the reported occurrence of Campylobacter in humans and animal food sources across different countries and regions in Africa. Campylobacter infection is particularly prevalent in the paediatric population and has been isolated from farm animals, particularly poultry, and foods of animal origin. The reported prevalence of Campylobacter in children under the age of five years ranges from 2% in Sudan to 21% in South Africa. In poultry, the prevalence ranges from 14.4% in Ghana to 96% in Algeria. This review also highlights the alarming trend of increased Campylobacter resistance to clinically important antimicrobials, such as ciprofloxacin and erythromycin, in humans and food animals in Africa. This review adds to our understanding of the global epidemiology of Campylobacter at the human–food animal interface, with an emphasis from the African perspective. Interinstitutional and intersectoral collaborations, as well as the adoption of the One Health approach, would be useful in bridging the gaps in the epidemiological knowledge of Campylobacter in Africa.

Characterization and Phylogenetic Analysis of Campylobacter Species Isolated from Paediatric Stool and Water Samples in the Northwest Province, South Africa

Antibiotic-resistant Campylobacter could adversely affect treatment outcomes, especially in children. We investigated the antibiotic susceptibility profiles, virulence potentials and genetic relatedness of Campylobacter spp. from paediatric and water samples in the North West Province, South Africa. Overall, 237 human and 20 water isolates were identified using culture and real-time polymerase chain reaction (PCR). The antibiotic susceptibility profiles were determined using the disk diffusion method. Gradient strips were used to determine the minimum inhibitory concentration of each antibiotic. Antibiotic resistance (gryA, tetO and 23S rRNA 2075G and 2074C) and virulence (cadF and ciaB) genes were also investigated using PCR. A phylogenetic tree to ascertain the clonality between water and clinical isolates was constructed using MEGA 7. Overall, 95% (water) and 64.7% (human) of the isolates were resistant to at least one antibiotic tested. The highest resistance was against clarithromycin (95%) for water and ampicillin (60.7%) for human isolates. The 23S rRNA 2075G/2074C mutation was the most expressed resistance gene. Phylogenetic reconstruction revealed eight intermixed clades within water and human Campylobacter isolates. This study suggests the possible circulation of potentially pathogenic antibiotic-resistant Campylobacter in the Northwest Province, South Africa with drinking water being a possible vector for disease transmission in this area.

Immunogenicity and protective efficacy of mucosal delivery of recombinant hcp of Campylobacter jejuni Type VI secretion system (T6SS) in chickens

The type VI secretion system (T6SS) has recently emerged as a new pattern of protein secretions in Campylobacter jejuni (C. jejuni). Within the T6SS cluster, hemolysin co-regulated protein (hcp) is considered as a hallmark of functional T6SS and holds key role in bacterial virulence. As poultry is the primary reservoir of C. jejuni and the major sources for human infection, we evaluated the capacity of recombinant hcp (rhcp) immunization in blocking C. jejuni colonization in chickens with an aim to control bacterial transmission to humans via poultry food chain. Considering the mucosal route is the primary portal for C. jejuni entry and gut mucosa offers the apposite site for C. jejuni adherence, we investigated the immune-protective potential of intra-gastric administration of rhcp using chitosan-based nanoparticles. To achieve this goal, full length coding sequence of hcp gene from C. jejuni was cloned and expressed in E. coli. Purified rhcp was entrapped in chitosan-Sodium tripolyphosphate nanoparticles (CS-TPP NPs) and orally gavaged in chickens. Our results suggest that intra-gastric immunization of CS-TPP-rhcp induces consistent and steady increase in intestinal (sIgA) and systemic antibody (IgY) response against rhcp with significant reduction in cecal load of C. jejuni. The protection afforded by rhcp associated cellular responses with Th1 and Th17 profile in terms of increased expression of NFkB, IL-1β, IL-8, IL-6, IFN-γ and IL-17 A genes. Though systemic immunization of rhcp with IFA resulting in a robust systemic (IgY) and local (sIgA) antibody response, mucosal administration of rhcp loaded CS-TPP NPs was found to be superior in terms of bacterial clearance. Altogether, present study suggests that chitosan based intra-gastric delivery of rhcp have several advantages over the injectable composition and could be a promising vaccine approach to effectively control C. jejuni colonization in chickens.

Clinical impact of the type VI secretion system on virulence of Campylobacter species during infection

BACKGROUND

The clinical course of Campylobacter infection varies in symptoms and severity depending on host factors, virulence of the pathogen and initiated therapy. The type VI secretion system (T6SS) has been identified as a novel virulence factor, which mediates contact-dependent injection of enzymes and toxins into competing bacteria or host cells and facilitates the colonisation of a host organism. We aimed to compare the clinical course of Campylobacter infection caused by strains with and without the T6SS and identify possible associations between this putative virulence factor and the clinical manifestations of disease.

METHODS

From April 2015 to January 2017, patients with detection of Campylobacter spp. were identified at the University Hospital of Basel and the University Children's Hospital of Basel and included in this case-control study. Presence of the T6SS gene cluster was assayed by PCR targeting the hcp gene, confirmed with whole genome sequencing. Pertinent clinical data was collected by medical record review. Differences in disease- and host-characteristics between T6SS-positive (case) and -negative (control) were compared in a uni- and multi-variable analysis. Hospital admission, antibiotic therapy, admission to intensive care unit, development of bacteraemia and in-hospital mortality were considered as clinical endpoints.

RESULTS

We identified 138 cases of Campylobacter jejuni infections and 18 cases of Campylobacter coli infections from a paediatric and adult population. Analyses were focused on adult patients with C. jejuni (n = 119) of which 16.8% were T6SS-positive. Comparisons between T6SS-positive and -negative C. jejuni isolates did not reveal significant differences regarding clinical manifestations or course of disease. All clinical endpoints showed a similar distribution in both groups. A higher score in the Charlson Comorbidity Index was associated with T6SS-positive C. jejuni isolates (p < 0.001) and patients were more likely to have a solid organ transplant and to be under immunosuppressive therapy.

CONCLUSIONS

Our study does not provide evidence that T6SS is associated with a more severe clinical course. Interestingly, T6SS-positive isolates are more commonly found in immunocompromised patients: an observation which merits further investigation.