Increase in Number of Positive Clostridioides difficile Results Among Pediatric Patients in Community in British Columbia, Canada in 2022-2024
Eugene Y H Yeung, Roxanna S D MohammedAbstract
Background
Since 2022, diagnostic laboratories in British Columbia (BC), Canada, have been advised to replace traditional bacterial, viral and parasitic intestinal pathogen testing with multiplex infectious diarrhea panel nucleic-acid amplification testing (IDP-NAAT), which contains a minimum of 14 common pathogens, including Clostridioides difficile. However, multiplex testing can lead to false positive results of targets which are not even in the clinicians’ differentials. The Canadian Paediatric Society has advised precautions in interpretation of Clostridioides difficile testing, especially in children <5 years of age who may have asymptomatic carriage of this bacteria. Testing for Clostridioides difficile is not routinely recommended for healthy infants younger than one year of age. LifeLabs BC implemented the IDP-NAAT in September 2023 and conducted a retrospective audit to determine whether the number of Clostridioides difficile positive results increased since the implementation, signaling a pseudo-outbreak.
Methods
LifeLabs BC microbiology laboratories are connected with 129 collection centres in urban and rural communities in the province and provided the laboratory data on Clostridioides difficile. An audit was conducted from September 2022 to August 2023, one year prior to implementation of IDP-NAAT in LifeLabs BC, and from October 2023 to September 2024, one year after the implementation of IDP-NAAT. Chi-square tests with Yates correction were used to compare differences before and after implementation of IDP-NAAT.
Results
Prior to implementation of IDP-NAAT, 149 of 1712 pediatric patient’s (age <18 years) stool specimens (8.70%) submitted for testing was positive for Clostridioides difficile. Among these positive results, 32 and 50 of them were from children <1 and 1-5 years of age, respectively. After the implementation of IDP-NAAT, 481 of 7547 of the pediatric patients’ stool specimens (6.37%; p < 0.05 vs. prior) submitted for testing was positive for Clostridioides difficile. Among these positive results, 75 and 206 of them were from children <1 and 1-5 years of age, respectively.
Conclusions
Although the positivity rate of Clostridioides difficile among pediatric patients’ stool specimens was significantly lower after the implementation of IDP-NAAT, the number of positive results increased more than three times, suggesting a pseudo-outbreak due to change in test methodology. This increase could mislead clinicians to overprescribe for Clostridioides difficile colonization rather than infection. More communications and educations may be warranted to remind clinicians that positive Clostridioides difficile NAAT results are not always indicative of infection, especially among pediatric patients, due to implementation of multiplex testing.