Clinico-bacteriological Study and Molecular Detection of Campylobacter in Childhood Diarrhoea: A Cross-sectional Study

Abstract

Introduction: Campylobacter infections cause diarrhoeal diseases as frequently as Salmonella and Shigella infections. The prevalence of Campylobacter infection among children with acute diarrhoea in developing countries ranges from 5-35%. Diagnosing Campylobacter infections is challenging as the organism is difficult to isolate, grow, and identify. Currently, no best-practice clinical or public health laboratory guidelines exist for laboratory diagnosis of Campylobacter infections. Aim: To explore the clinical and bacterial aspects of childhood diarrhoea, emphasising the prevalence and molecular detection of Campylobacter. Materials and Methods: A hospital-based cross-sectional descriptive study was conducted with 55 stool samples of children under five with diarrhoea or dysentery at the Department of Microbiology, JSS Medical College, Mysuru, Karnataka, India, from October 2016 to September 2017. All stool samples were inoculated onto Campylobacter selective and non selective media with filtration and incubated in microaerophilic conditions. The culture isolates were identified by standard phenotypic tests. Molecular characterisation of Campylobacter was performed targeting the Campylobacter adhesion to fibronectin F (cadF) gene. The presence of a phylogenetically conserved 16S ribosomal Ribonucleic Acid (16SrRNA) domain was studied, followed by specific detection of pathogenic Campylobacter species. The Statistical Package for Social Sciences (SPSS) version 22.0 was used for statistical analysis. Descriptive statistics like percentage, mean, and Standard Deviation (SD) were applied. Results: Campylobacter was isolated by culture in one out of 55 stool samples. The isolate was confirmed to be Campylobacter jejuni by phenotypic tests. Campylobacter genus-level Polymerase Chain Reaction (PCR) was positive for 6 samples (10.9%). Six positive samples were subjected to species-level PCR; all were positive for C. jejuni. Out of 55 stool samples, two diarrheagenic Escherichia coli, two Shigella sonnei, one Shigella dysenteriae, and one Salmonella enterica serovar Typhi were also identified. Conclusion: Culture is insufficiently sensitive for diagnosing Campylobacter infection compared with nucleic acid-based diagnostics. Nucleic acid-based diagnostics offer increased sensitivity, can determine both the presence and burden of infection, and can distinguish between Campylobacter infections at the species level. Therefore, PCR is recommended, if feasible, as the preferred diagnostic modality for detecting Campylobacter infection.

Keywords

• campylobacter infection
• dysentery
• molecular diagnostic techniques