Direct detection of Clostridium perfringens enterotoxin in patients' stools during an outbreak of food poisoning

Diagnostic Accuracy of Nucleic Acid Amplification-Based Assays for Clostridium perfringens-Associated Diseases: a Systematic Review and Meta-analysis

Timely and accurate methods for detecting Clostridium perfringens-associated diseases (CPAD) are crucial to improve patient care. A number of studies have evaluated the accuracy of nucleic acid amplification tests (NAAT) in detecting CPAD, but decisive results about their effectiveness have not been reported. We conducted a meta-analysis to evaluate the diagnostic performance of NAAT for detecting C. perfringens in clinical diarrheal samples. Five databases including PubMed, Embase, Scopus, Web of Science, and the Cochrane library were systematically probed for studies published before 6 December 2019. From 2,632 citations, we identified five eligible studies comprising 817 samples. Three studies (n = 695 samples) compared NAAT with a microbiological culture while the other three studies (n = 322 samples) compared NAAT with an immunoassay. NAAT revealed higher diagnostic accuracy against immunoassay (sensitivity, 0.53 [95% confidence interval [CI], 0.35 to 0.7]; specificity, 0.97 [95% CI, 0.95 to 0.99]; positive likelihood ratio [PLR], 23.2 [95% CI, 3.49 to 153.98]; negative likelihood ratio [NLR], 0.25 [95% CI, 0 to 245.28]; diagnostic odds ratio [DOR], 74.11 [95% CI, 2.11 to 2,593.7]) than microbiological culture (sensitivity, 0.31 [95% CI, 0.22 to 0.41]; specificity, 0.95 [95% CI, 0.93 to 0.97]; PLR, 11.56 [95% CI, 3.87 to 34.6]; NLR, 0.57 [95% CI, 0.27 to 1.21]; DOR, 18.1 [95% CI, 4.83 to 67.8]). NAAT pooled specificity was consistently ≥95% against that of applied reference standards. A meta-regression and subgroup analysis of sample condition, gene target, study design, and reference standards could not explain the heterogeneity (P > 0.05) in the diagnostic efficiency. The analysis has demonstrated that the diagnostic accuracy of NAAT is relatively insufficient to replace traditional reference standards as a single diagnostic test. NAAT can be applied in combination with microbiological culture because of the advantage of time to result and in scenarios where traditional tests are not feasible. Further investigations in this direction with larger sample sizes are still warranted to support our findings.

A Five Site Clostridium Perfringens Food-Borne Outbreak: A Retrospective Cohort Study

Introduction

In May of 2012, we investigated a food-borne Clostridium perfringens outbreak in Slovenia involving a single kitchen and five venues, with 477 exposed persons.

Methods

In order to identify the causative agent, vehicle of infection and source of contamination, we conducted microbiological and environmental investigations and an analytical cohort study (n = 138).

Results

The case definition in the outbreak was met by 104 persons. Predominant symptoms were diarrhoea, nausea and abdominal cramps. Median incubation time and duration of illness were 12 and 22.5 hours respectively. Stool samples were collected from 18 persons and in 13 C. perfringens spores were present; enterotoxin was detected in 9 persons. PCR and PFGE analysis of isolates from a cook with earlier onset time, who did not consume the implicated food, and cases from four venues showed the same strain of C. perfringens type A (with cpe-gene), indistinguishable by PFGE analysis. No food samples could be obtained. An analytical study showed that one food item (French salad) was the most likely vehicle of infection (RR: 6.35; 95% CI: 1.62–24.90).

Conclusions

This was the largest C. perfringens outbreak in Slovenia to date. Proper analytical study in combination with detailed laboratory investigation with genotypisation enabled us to identify a causative agent, vehicle of infection and possible source of contamination. Fast response and interdisciplinary collaboration led to timely implementation of control measures. These have led to the kitchen acquiring new equipment and improving staff knowledge of risks and processes, thus reducing the likelihood of future reoccurrences.

Waterborne outbreak of Norwalk-like virus gastroenteritis at a tourist resort, Italy

In July 2000, an outbreak of gastroenteritis occurred at a tourist resort in the Gulf of Taranto in southern Italy. Illness in 344 people, 69 of whom were staff members, met the case definition. Norwalk-like virus (NLV) was found in 22 of 28 stool specimens tested. The source of illness was likely contaminated drinking water, as environmental inspection identified a breakdown in the resort water system and tap water samples were contaminated with fecal bacteria. Attack rates were increased (51.4%) in staff members involved in water sports. Relative risks were significant only for exposure to beach showers and consuming drinks with ice. Although Italy has no surveillance system for nonbacterial gastroenteritis, no outbreak caused by NLV has been described previously in the country.