An Escherichia coli pseudo-outbreak in the intensive care units of a university hospital.

Abstract

Background: The term 'pseudo-outbreak' refers to a condition in which a microorganism is found in cultures at a greater rate than expected due to contamination of materials that would normally be sterile. This situation cannot be clinically correlated with the infection suggested by the culture results. This can be confusing depending on the patient's clinical condition, especially in intensive care units (ICU). The pseudo-outbreak with Escherichia coli in patients in ICUs will be discussed in this study to emphasize the importance of strict adherence to microbiology policies and procedures.

Methods: In September 2022, growths of Escherichia coli were found in the endotracheal aspirate cultures of six children and eighteen adults in the ICU.

Results: The identification of the same microbial agent in 24 patients prompted an investigation into a potential outbreak. The infection control committee compiled a comprehensive patient list to facilitate the assessment. Given that the healthcare personnel and infrastructure of each ICU were distinct and functioned independently, the possibility of cross-contamination within these units was deemed unlikely. Consequently, attention was directed toward the microbiology laboratory as a potential source of the outbreak. A thorough review of culture processing steps and laboratory equipment was conducted. This investigation revealed that the saline solution used for the passage of endotracheal aspiration cultures was contaminated, suggesting a laboratory-associated contamination event as the probable cause.

Conclusions: By strictly adhering to the latest protocols, the disinfection and sterilization chain can ensure the safe use of both invasive and non-invasive medical equipment. This manuscript aims to raise awareness among pediatricians and pediatric infectious disease specialists regarding the occurrence of pseudo-outbreaks. A pseudo-outbreak is indicative of a disruption in the sterilization chain.