Background Campylobacter is an important cause of diarrhoeal illness in children. As isolation of these fastidious bacteria from stool samples is laborious and expensive, it is not routinely investigated in certain geographical areas. This study aimed to demonstrate the utility of Gram staining as a rapid and cost-effective screening method for the detection of Campylobacter in stool specimens from children with acute diarrhoea. Methods Stool samples from 138 children below 12 years of age at a tertiary care centre were screened by Gram staining for Gram-negative spiral bacilli. Smear-positive samples were subjected to culture on campylobacter selective medium. Isolates were confirmed by polymerase chain reaction (PCR) targeting the genus-specific 16S rRNA gene and the mapA and ceuE genes, to Campylobacter jejuni and C.coli respectively. Antibiotic susceptibility testing was performed by the Kirby–Bauer disc diffusion method against erythromycin and ciprofloxacin. Results Gram-negative spiral bacilli were detected in 15 (10.86%) and 13 were confirmed by culture (positive predictive value of Gram staining: 86.66%). One sample was positive on direct PCR with no growth. Of the isolates, 11 were identified as C. jejuni, one C.coli, and one as non-jejuni/non-coli. All isolates were susceptible to the tested antibiotics. Conclusion Gram staining of stool is rapid, low-cost and practical screening method for campylobacteriosis. With positive predictive value of 86.66%, it offers a valuable first-line diagnostic tool. C.jejuni is the predominant species in this paediatric population and the absence of antibiotic resistance supports the continued use of erythromycin and ciprofloxacin as first-line therapeutic agents.
Background Symptoms of many gastrointestinal infections are similar, making it difficult to differentiate the causative agents. Automated PCR-based diagnostic systems can rapidly detect and identify pathogens responsible for these infections. Methods BD Enteric Bacterial Panel plus (EBP plus Assay) for BD COR System was assessed versus a single comparator (BioFire™ FilmArray™ GI Panel) or a composite reference (≥2 of 3 assays: BioFire FilmArray GI Panel, BioCode™ GPP, and BD MAX™ EBP/xEBP) for detecting enteric pathogens using patient stool specimens. Positive and negative percent agreement (PPA and NPA) between EBP plus Assay and comparator method(s) were calculated with 95% two-sided confidence intervals (CIs). Agreement ≥90% with CI lower bounds ≥80% was considered acceptable performance. Contrived specimens were included for low prevalence targets. Results There were 1737 specimens analyzed. NPA met performance thresholds (≥98.4%) for all targets. PPA met performance thresholds for Salmonella spp., Campylobacter spp., and Shiga toxin. Due to low prevalence in the study population, the PPA lower bound of the 95% CI was below the threshold for Shigella spp./enteroinvasive Escherichia coli, Vibrio spp., and Yersinia enterocolitica, while PPA point estimates were not met for Plesiomonas shigelloides and enterotoxigenic E. coli (ETEC). PPA and NPA thresholds were met in contrived specimen testing for Shiga toxin, Vibrio spp., Plesiomonas shigelloides, Yersinia enterocolitica, and ETEC. Conclusions The EBP plus Assay implemented on the BD COR System demonstrated good concordance with the comparator method(s) for detecting enteric bacterial pathogens in stool and is suited for high-throughput laboratories seeking to enhance task automation without impacting accuracy.
The global surge in nontuberculous mycobacteria (NTM) infections, which clinically mimic Mycobacterium tuberculosis (MTB) infections, underscores the need for rapid differential diagnosis. This study evaluated the analytical and clinical performance of the STANDARD™ M10 MTB/NTM assay, a fully automated, cartridge-based, sample-to-result real-time PCR system. Analytical performance was assessed using contrived artificial sputum samples to evaluate inclusivity (3 MTB-complex, 12 NTM species), cross-reactivity (65 respiratory pathogens), and interference (33 substances). The limit of detection (LoD) was compared with two commercial assays, the AdvanSure™ TB/NTM Real-time PCR and the Anyplex™ MTB/NTMe Real-time Detection, using three MTB-complex strains (M. tuberculosis H37Rv, M. bovis, and M. bovis BCG Pasteur) and 15 NTM species. Clinical validation was performed using 70 clinical sputum specimens against both comparators. The STANDARD™ M10 MTB/NTM demonstrated excellent inclusivity and high specificity, with no cross-reactivity or analytical interference (△Ct ≤ 2.0). In the LoD comparison, the STANDARD™ M10 MTB/NTM achieved a lower LoD for MTB H37Rv (101 CFU/mL) and major NTM species (M. avium, M. intracellulare, M. abscessus subsp. abscessus) than the comparators, demonstrating superior analytical sensitivity. Moreover, the STANDARD™ M10 MTB/NTM successfully detected M. xenopi, M. scrofulaceum, and M. malmoense, which were missed by alternative assays. In clinical evaluation, it demonstrated 100% overall agreement (95% confidence interval (CI), 94.8–100.0) with the AdvanSure™ TB/NTM Real-time PCR and Anyplex™ MTB/NTMe Real-time Detection assays across a Ct range of 27.41–33.17. The STANDARD™ M10 MTB/NTM assay offers exceptional analytical sensitivity, broad coverage, and, in the absence of an independent reference standard, complete agreement with two established laboratory-based platforms. By incorporating a fully automated workflow and minimizing turnaround time, this system serves as a reliable tool for rapid MTB/NTM differentiation in point-of-care settings.
