Thermophilic Campylobacter species are clinically important aetiologies of gastroenteritis in humans throughout the world. The colonization of different animal reservoirs by Campylobacter poses an important risk for humans through shedding of the pathogen in livestock waste and contamination of water sources, environment, and food. A review of published articles was conducted to obtain information on the prevalence and antimicrobial resistance (AMR) profiles of thermophilic Campylobacter species in humans and animals in sub-Saharan Africa (SSA). Electronic databases, namely, PubMed, Google Scholar, Research4life-HINARI Health, and Researchgate.net, were searched using the following search terms “thermophilic Campylobacter,” “Campylobacter jejuni,” “Campylobacter coli,” “diarrhea/diarrhoea,” “antimicrobial resistance,” “antibiotic resistance,” “humans,” “animals,” “Sub-Saharan Africa,” and “a specific country name.” Initially, a total of 614 articles were identified, and the lists of references were screened in which 22 more articles were identified. After screening, 33 articles on humans and 34 on animals and animal products were included in this review. In humans, Nigeria reported the highest prevalence (62.7%), followed by Malawi (21%) and South Africa (20.3%). For Campylobacter infections in under-five children, Kenya reported 16.4%, followed by Rwanda (15.5%) and Ethiopia (14.5%). The country-level mean prevalence in all ages and under-five children was 18.6% and 9.4%, respectively. The prevalence ranged from 1.7%–62.7% in humans and 1.2%–80% in animals. The most reported species were C. jejuni and C. coli. The AMR to commonly used antimicrobials ranged from 0–100% in both humans and animals. Poultry consumption and drinking surface water were the main risk factors for campylobacteriosis. The present review provides evidence of thermophilic Campylobacter occurrence in humans and animals and high levels of AMR in SSA, emphasizing the need for strengthening both national and regional multisectoral antimicrobial resistance standard surveillance protocols to curb both the campylobacteriosis burden and increase of antimicrobial resistance in the region.

Diarrhea, often caused by microorganisms, has been associated with high morbidity and mortality in Africa. Increased rates of antimicrobial-resistant pathogens have reignited the quest for alternative therapies. This review aimed at identifying medicinal plants used in the treatment of human diarrheal cases in Rwanda and analyzing their ethnobotany, ethnopharmacology, and phytochemistry. We searched PubMed/Medline, Google Scholar, ScienceDirect, and the Web of Science for published articles on medicinal plants used to treat diarrhea in Rwanda. Additionally, specialized herbarium documents of different institutes were reviewed. Articles were assessed for relevance, quality, and taxonomical accuracy before being included in this review. Overall, 63 species of medicinal plants belonging to 35 families were recorded. Asteraceae was the predominant family with six species, followed by Fabaceae and Lamiaceae, with five species each. The most reported species with anti-diarrheal properties were Vernonia amygdalina Delile, Tetradenia riparia (Hochst.) Codd, Clerodendrum myricoides R. Br., and Chenopodium ugandae (Aellen) Aellen. Leaves (66.7%) and roots (17.5%) were the commonly used plant parts in the preparation of medicine. Phytochemicals from medicinal plants with antidiarrheic activities were sesquiterpene lactones (V. amygdalina); terpene, sterols, saponosides, and flavonoids (C. ugandae); saponins and tannins (T. riparia); and tannins, flavonoids, and alkaloids (C. myricoides). Six studies tested the antimicrobial activities of the plants against bacteria and viruses known to cause diarrhea. Erythrina abyssinica, Euphorbia tirucalli, Dracaena afromontana, and Ficus thonningii are socio-culturally important. Further research on toxicity and posology is needed to ensure the safety of medicinal plants.

Campylobacter species have developed resistance to existing antibiotics. The development of alternative therapies is, therefore, a necessity. This study evaluates the susceptibility of Campylobacter strains to selected natural products (NPs) and frontline antibiotics. Two C. jejuni strains (ATCC® 33560TM and MT947450) and two C. coli strains (ATCC® 33559TM and MT947451) were used. The antimicrobial potential of the NPs, including plant extracts, essential oils, and pure phytochemicals, was evaluated by broth microdilution. The growth was measured by spectrophotometry and iodonitrotetrazolium chloride. Antibiotic resistance genes (tet(O) and gyrA) were characterized at the molecular level. The minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) ranged from 25 to 1600 µg/mL. Cinnamon oil, (E)-Cinnamaldehyde, clove oil, eugenol, and baicalein had the lowest MIC and MBC values (25–100 µg/mL). MT947450 and MT947451 were sensitive to erythromycin and gentamicin but resistant to quinolones and tetracycline. Mutations in gyrA and tet(O) genes from resistant strains were confirmed by sequencing. The findings show that NPs are effective against drug-sensitive and drug-resistant Campylobacter strains. The resistance to antibiotics was confirmed at phenotypic and genotypic levels. This merits further studies to decipher the action mechanisms and synergistic activities of NPs.

Thermophilic Campylobacter species are among the major etiologies of bacterial enteritis globally. This study aimed at assessing the antimicrobial resistance (AMR) profiles, virulence genes, and genetic diversity of thermophilic Campylobacter species isolated from a layer poultry farm in South Korea. One hundred fifty-three chicken feces were collected from two layer poultry farms in Gangneung, South Korea. The Campylobacter species were isolated by cultural techniques, while PCR and sequencing were used for species confirmation. Antimicrobial susceptibility testing for six antimicrobials [ciprofloxacin (CIP), nalidixic acid (NAL), sitafloxacin (SIT), erythromycin (ERY), tetracycline (TET), and gentamicin (GEN)] was carried out by broth microdilution. Three AMR and nine virulence genes were screened by PCR. Genotyping was performed by flaA-restriction fragment length polymorphism (RFLP) and multilocus sequence typing (MLST). Of the 153 samples, Campylobacter spp. were detected in 55 (35.9%), with Campylobacter jejuni and Campylobacter coli being 49 (89.1%) and six (10.9%), respectively. High-level resistance was observed for CIP (100%), NAL (100%), and TET (C. jejuni, 93.9%; C. coli: 83.3%). No resistance was observed for SIT. The missense mutation (C257T) in gyrA gene was confirmed by sequencing, while the tet(O) gene was similar to known sequences in GenBank. The rate of multidrug-resistant (MDR) strains was 8.2%, and they all belonged to C. jejuni. All Campylobacter isolates possessed five virulence genes (cdtB, cstII, flaA, cadF, and dnaJ), but none possessed ggt, while the rates for other genes (csrA, ciaB, and pldA) ranged between 33.3 and 95.9%. The flaA-RFLP yielded 26 flaA types (C. jejuni: 21 and C. coli: five), while the MLST showed 10 sequence types (STs) for C. jejuni and three STs for C. coli, with CC-607 (STs 3611) and CC-460 (ST-460) being predominant. Among the 10 STs of C. jejuni, three were newly assigned. The findings of this study highlight the increased resistance to quinolones and TET, the virulence potential, and the diverse genotypes among Campylobacter strains isolated from the layer poultry farm.

Campylobacter jejuni is one of the major aetiologies of diarrhoea. Understanding the processes and virulence factors contributing to C. jejuni fitness is a cornerstone for developing mitigation strategies. Two-component signal transduction systems, known as two-component systems (TCSs), along with single regulators with no obvious cognate histidine kinase, help pathogens in interacting with their environments, but the available literature on C. jejuni is limited. A typical TCS possesses histidine kinase and response regulator proteins. The objective of this review was to provide insights into the virulence of C. jejuni associated with TCSs and single regulators. Despite limited research, TCSs are important contributors to the pathogenicity of C. jejuni by influencing motility (FlgSR), colonisation (DccRS), nutrient acquisition (PhosSR and BumSR), and stress response (RacRS). Of the single regulators, CbrR and CosR are involved in bile resistance and oxidative stress response, respectively. Cross-talks among TCSs complicate the full elucidation of their molecular mechanisms. Although progress has been made in characterising C. jejuni TCSs, shortfalls such as triggering signals, inability to induce mutations in some genes, or developing suitable in vivo models are still being encountered. Further research is expected to shed light on the unexplored sides of the C. jejuni TCSs, which may allow new drug discoveries and better control strategies.

Thermophilic Campylobacter species of poultry origin have been associated with up to 80% of human campylobacteriosis cases. Layer chickens have received less attention as possible reservoirs of Campylobacter species. Initially, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of two archived Campylobacter isolates (Campylobacter jejuni strain 200605 and Campylobacter coli strain 200606) from layer chickens to five antimicrobials (ciprofloxacin, nalidixic acid, erythromycin, tetracycline, and gentamicin) were determined using broth microdilution while the presence of selected antimicrobial resistance genes was performed by polymerase chain reaction (PCR) using specific primers. Whole-genome sequencing (WGS) was performed by the Illumina HiSeq X platform. The analysis involved antimicrobial resistance genes, virulome, multilocus sequence typing (MLST), and phylogeny. Both isolates were phenotypically resistant to ciprofloxacin (MIC: 32 vs. 32 µg/mL), nalidixic acid (MIC: 128 vs. 64 µg/mL), and tetracycline (MIC: 64 vs. 64 µg/mL), but sensitive to erythromycin (MIC: 1 vs. 2 µg/mL) and gentamicin (MIC: 0.25 vs. 1 µg/mL) for C. jejuni strain 200605 and C. coli strain 200606, respectively. WGS confirmed C257T mutation in the gyrA gene and the presence of cmeABC complex conferring resistance to FQs in both strains. Both strains also exhibited tet(O) genes associated with tetracycline resistance. Various virulence genes associated with motility, chemotaxis, and capsule formation were found in both isolates. However, the analysis of virulence genes showed that C. jejuni strain 200605 is more virulent than C. coli strain 200606. The MLST showed that C. jejuni strain 200605 belongs to sequence type ST-5229 while C. coli strain 200606 belongs to ST-5935, and both STs are less common. The phylogenetic analysis clustered C. jejuni strain 200605 along with other strains reported in Korea (CP028933 from chicken and CP014344 from human) while C. coli strain 200606 formed a separate cluster with C. coli (CP007181) from turkey. The WGS confirmed FQ-resistance in both strains and showed potential virulence of both strains. Further studies are recommended to understand the reasons behind the regional distribution (Korea, China, and Vietnam) of such rare STs.

Background: A growing number of Campylobacter species other than C. jejuni and C. coli have been considered as emerging human and animal pathogens. However, the contribution of these species to human gastroenteritis is poorly documented. This study aimed at detecting Campylobacter species from human and cattle faecal samples in Kilosa district, Tanzania using Polymerase Chain Reaction (PCR) amplification of the 16S rRNA gene, and Sanger sequencing . Methods: A total number of 100 faecal samples (70 from human and 30 from cattle) were collected from diarrheic and non-diarrheic patients and healthy cattle in Kilosa district, Tanzania from July to October 2019. Species identification was conducted by PCR and 16S rRNA sequencing. The phylogenetic analysis was carried out by comparison of the 16S rRNA gene sequences to reference strains by the Neighbor-Joining method in MEGA X. Results: Campylobacter species detection rate by PCR was 65.7% (46/70) and 20% (6/30) in humans and cattle, respectively. There were five human diarrheic cases, four showed Campylobacter presence and two were from children ≤15 years of age. In humans, the 16S rRNA sequencing revealed that C. concisus was the most predominant species occurring at a frequency of 37.8% (14/37), followed by uncultured Campylobacter spp. 24.3% (9/37) and C. hominis 21.6% (8/37). The least represented species were C. jejuni and C. lanienae all occurring at 2.7% (1/37). In cattle, five (100%) sequenced PCR products matched with C. lanienae . Phylogenetic analysis revealed that Campylobacter 16S rRNA sequences were closely related to C. concisus , uncultured Campylobacter sp., C. hominis , and C. gracilis . Conclusion: The non- C. jejuni / C. coli species are present in human and cattle faecal samples and their true occurrence is probably under-reported due to shortcomings of conventional techniques used in most diagnostic microbiology laboratories. Based on our findings, we recommend that molecular techniques be adopted for direct detection of Campylobacter species during routine laboratory screening and surveillance studies. Keywords: Campylobacter , molecular diagnostics, polymerase chain reaction, sequencing, gastroenteritis, Tanzania

A growing number of Campylobacter species other than C. jejuni and C. coli have been considered as emerging human and animal pathogens but their contribution to human gastroenteritis is poorly documented. This study aimed at detecting Campylobacter species from human and cattle faecal samples in Kilosa District, Tanzania using molecular techniques without culture. Seventy (70) faecal samples were collected from five diarrheic and 65 non-diarrheic human patients attending Kilosa District Hospital in Tanzania from July to October 2019. During the same period, 30 faecal samples were also collected from healthy cattle in the same district. Genus and species identification of Campylobacter was conducted on the samples using molecular techniques [the polymerase chain reaction (PCR) and 16S rRNA sequencing]. Phylogenetic analysis was carried out by comparison of the 16S rRNA gene sequences to reference strains by the Neighbor-Joining method in MEGA X. Campylobacter species detection rate by PCR was 65.7% (46/70) and 20% (6/30) in humans and cattle, respectively.  There were five human diarrheic cases, four of which were positive for Campylobacter and of these, two were children ≤15 years of age. In humans, 16S rRNA sequencing revealed that C. concisus was the most predominant species occurring at a frequency of 37.8% (14/37), followed by uncultured Campylobacter spp. 24.3% (9/37) and C. hominis 21.6% (8/37). The least represented species were C. jejuni and C. lanienae, all occurring at 2.7% (1/37). In cattle, five (100%) sequenced PCR products matched with C. lanienae. Phylogenetic analysis revealed that with the exception of C. lanienae, 16S rRNA sequences of Campylobacter species were closely related to the reference strains used (Percent identity: 90.51-96.56%). Based on our findings, we recommend that molecular techniques, mainly PCR be adopted for the direct detection of Campylobacter species during laboratory screening and surveillance studies.