Outbreak of multidrug-resistant Staphylococcus haemolyticus ST29 in a French neonatal unit

Staphylococcus haemolyticus is a clinically relevant coagulase-negative staphylococcus frequently responsible for hospital-acquired infections, especially in premature newborns.

To describe an outbreak of multidrug-resistant S. haemolyticus in a neonatal department.

The outbreak was investigated using classical methods, including screening of the patients, genotyping of the isolates and environmental survey. Numerous infection control measures were implemented.

In 2022 and 2023, a clonal outbreak of multidrug-resistant S. haemolyticus ST29 (40 infections and 71 carriages) occurred in the neonatology department of a University Hospital in France. The infection control measures implemented only partially controlled the outbreak. Although our investigation did not clearly identify the source and mode of transmission, a reservoir constituted by patients and transmission by healthcare workers are the most likely. This episode occurred in a context of countrywide outbreaks of S. haemolyticus ST29 in several French neonatology departments.

This prolonged outbreak of S. haemolyticus ST29 accounted for the increase in the incidence of S. haemolyticus-related infections in French neonatology departments. Implementation of proactive measures is crucial to limit the spread of such pathogens in neonatal ICUs.