BACKGROUND Aeromonas, Campylobacter and Salmonella species can cause gastrointestinal infections in humans. Information on the performance of detection methods is relevant to assess the impact of changes on surveillance. AIM We aimed to assess detection of Aeromonas , Campylobacter and Salmonella by culture and Seegene multiplex real-time PCR in faecal samples from patients with gastrointestinal symptoms. METHODS In 2023, all faecal samples submitted to a clinical microbiology laboratory in Sydney, Australia, were tested for Aeromonas , Campylobacter and Salmonella species by culture and Seegene PCR, both detecting at the genus level. The results were analysed descriptively and with binomial generalised linear model, quantile regression, censored regression model and Wald tests. RESULTS Of the 90,291 samples tested, more samples were positive with PCR than with culture for Aeromonas (PCR: 2.9%; culture: 0.5%) and Campylobacter (PCR: 4.2%; culture: 3.1%), but fewer for Salmonella species (PCR: 0.7%; culture: 0.8%). Of the culture-positive samples, 19.2% were negative for Aeromonas by PCR, 3.6% for Campylobacter and 23.0% for Salmonella . Of the PCR-positive samples, 81.9% were negative for Aeromonas by culture, 25.6% for Campylobacter and 14.2% for Salmonella . Quantification cycle (Cq) values were negatively associated with patient age for Aeromonas, indicating higher bacterial loads in older patients and positively associated with age for Campylobacter , indicating lower bacterial loads in older patients (p < 0.001). Also, Cq values were negatively associated with detection by culture and faecal calprotectin levels (p < 0.001). CONCLUSION These findings highlight the importance of pathogen- and method-specific interpretation of PCR and culture results in diagnostic testing and surveillance.
Yuwono et al. (Thu,) studied this question.