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Efficacy of cold enrichment techniques for recovery of Yersinia enterocolitica from human stools
Abstract:
Stool specimens from children with gastroenteritis and their household contacts were cultured for Yersinia enterocolitica by direct plating onto routine laboratory media. These stools were also inoculated into phosphate-buffered saline and subcultured to the same media after 1 day or 3 weeks of incubation at 4 degrees C. Y. enterocolitica was isolated from 174 index cases and 34 household contacts. One hundred eighty-one isolates were of serotype O:3, and the remaining 21 belonged to other serotypes. Eighty-one percent (147/181) of O:3 isolates were recovered by direct plating, and 6.1% (11/181) and 13% (23/181) were recovered by 1-day and 3-week cold enrichment, respectively. For other serotypes, 26% (7/27), 0%, and 74% (20/27) were isolated by direct plating, 1-day cold enrichment, and 3-week cold enrichment, respectively. The efficacy of the cold enrichment for the patients were still symptomatic, 94 and 6% of Y. enterocolitica were identified by direct plating and cold enrichment, respectively. Isolation rates were 66% by direct plating and 34% by cold enrichment when stools were obtained from asymptomatic carriers or from those convalescing from Y. enterocolitica gastroenteritis. These results indicate that the cold enrichment methods increase the sensitivity of Y. entercolitica culture methods considerably in convalescent and asymptomatic subjects but only minimally in patients with diarrhea caused by serotype O:3.
Insights
Cold enrichment significantly improves Yersinia enterocolitica detection in asymptomatic carriers and convalescent patients. Direct plating remains effective for symptomatic cases, especially for serotype O:3.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Diagnostics
Background:
- Yersinia enterocolitica is a significant cause of bacterial gastroenteritis in children.
- Accurate laboratory detection is crucial for diagnosis and public health surveillance.
- Standard culture methods may have limitations in detecting all Y. enterocolitica infections.
Purpose of the Study:
- To evaluate the efficacy of cold enrichment techniques for isolating Yersinia enterocolitica from stool specimens.
- To compare the sensitivity of direct plating versus cold enrichment for different patient groups and Y. enterocolitica serotypes.
Main Methods:
- Stool specimens from children with gastroenteritis and their contacts were cultured using direct plating.
- Specimens were also subjected to cold enrichment (1 day and 3 weeks at 4°C) before subculturing.
- Isolates were identified, serotyped (O:3 and others), and analyzed based on patient symptomatic status.
Main Results:
- Cold enrichment substantially increased Y. enterocolitica isolation rates in convalescent (34% vs. 66%) and asymptomatic subjects (74% vs. 26% for non-O:3 serotypes).
- Direct plating was highly effective (94%) for symptomatic patients, particularly for serotype O:3.
- Cold enrichment offered minimal benefit for serotype O:3 in symptomatic individuals.
Conclusions:
- Cold enrichment is a valuable adjunct to direct plating for enhancing Yersinia enterocolitica detection, especially in non-symptomatic individuals.
- The choice of culture method should consider the patient's clinical status and the Y. enterocolitica serotype.
- Optimized culture strategies improve the diagnostic yield for Yersinia enterocolitica infections.