Outbreak of penicillin-susceptible, eta-positive Staphylococcus aureus in a neonatal intensive care unit
5 affiliations
- 1Faculty of Engineering and Management, University of Applied Sciences Ingolstadt
- 2Department of Pediatrics and Adolescent Medicine, AMEOS St. Elisabeth Clinic
- 3Robert Koch Institute
- 4Department of Infectious Diseases and Infection Control, Ingolstadt Hospital
- 5Clinic St. Hedwig
Abstract
Staphylococcus aureus is one of the most common microorganisms causing wound infections, and outbreaks of multi-drug-resistant strains in neonatal intensive care units (NICUs) are a major concern. In Germany, screening patients for colonization with multi-drug-resistant bacteria is strongly recommended in these wards under national infection-control guidelines. Outbreaks caused by penicillin-susceptible strains are less commonly reported. In the first few months of 2024, penicillin-susceptible S. aureus was detected in 20 infants, of whom 10 developed confirmed infections, primarily purulent conjunctivitis. Using a cumulative sum (CUSUM) control chart applied to monthly acquisition counts from January 2021 to December 2025, an outbreak was identified between December 2023 and May 2024. Whilst the detection rate during the non-outbreak phase was 1.17 patients per month, it rose to 3.33 patients per month during the outbreak ( p < 0.001). The number of infections was also significantly higher, with 1.67 infections per month within the outbreak period compared to 0.30 infections per month ( p < 0.001). The median gestational age was lower in patients with a confirmed infection than in patients with colonization only (214.5 vs. 243.5 days, p = 0.029). Four isolates from three affected children had undergone detailed typing. All isolates exhibited the same spa - (t328), ST- (15), and CT- (38152) types. In the cgMLST analysis, these isolates form a single cluster. All four isolates harbored the eta gene, suggesting the potential for expression of exfoliative toxin A. Following implementation of a bundle of enhanced infection-control measures, no further outbreak-associated detections occurred. As part of this response, and because systematic identifiable staff screening was restricted by data-protection requirements, all staff members were offered voluntary anonymous screening for nasal S. aureus colonization and, where appropriate, access to mupirocin decolonization. Although the contribution of individual interventions cannot be determined, the temporal association suggests that the combined infection-control measures likely contributed to containment of the outbreak. Our report shows that antibiotic susceptible pathogens can cause outbreaks in NICUs. Surveillance that also includes susceptible pathogens may facilitate the detection and epidemiological assessment of suspicious clusters.
Related
- Cefazolin for Methicillin-Susceptible Staphylococcus aureus Bacteremia
- Chlorhexidine MIC distribution, efflux pump gene profiles, and genotypic characteristics among clinical methicillin-resistant and methicillin-susceptible Staphylococcus aureus isolates
- Delayed introduction, transmission variation and susceptible dynamics explain spatial asynchrony during Republic of Korea's large pertussis outbreak.
- Effectiveness and safety of cefazolin vs antistaphylococcal penicillins for methicillin-susceptible Staphylococcus aureus bacteremia: a multicenter real-world evaluation using the international TriNetX database
- Cefazolin versus Antistaphylococcal Penicillins for Methicillin-Susceptible Staphylococcus aureus Bacteremia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
BibTeX
@article{meintrup2026outbreak,
title = {{Outbreak of penicillin-susceptible, eta-positive Staphylococcus aureus in a neonatal intensive care unit}},
author = {David Meintrup and Daniel Vilser and Franziska Layer-Nicolaou and Fabian Müller and Birgit Strommenger and Beate Rieß and Brigitte Hücherig and Stefan Borgmann},
journal = {Frontiers in Microbiology},
year = {2026},
month = oct,
doi = {10.3389/fmicb.2026.1946607},
url = {https://www.frontiersin.org/articles/10.3389/fmicb.2026.1946607/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Outbreak of penicillin-susceptible, eta-positive Staphylococcus aureus in a neonatal intensive care unit
AU - David Meintrup
AU - Daniel Vilser
AU - Franziska Layer-Nicolaou
AU - Fabian Müller
AU - Birgit Strommenger
AU - Beate Rieß
AU - Brigitte Hücherig
AU - Stefan Borgmann
PY - 2026
DA - 2026/10/27
JO - Frontiers in Microbiology
DO - 10.3389/fmicb.2026.1946607
UR - https://www.frontiersin.org/articles/10.3389/fmicb.2026.1946607/full
AB - Staphylococcus aureus is one of the most common microorganisms causing wound infections, and outbreaks of multi-drug-resistant strains in neonatal intensive care units (NICUs) are a major concern. In Germany, screening patients for colonization with multi-drug-resistant bacteria is strongly recommended in these wards under national infection-control guidelines. Outbreaks caused by penicillin-susceptible strains are less commonly reported. In the first few months of 2024, penicillin-susceptible S. aureus was detected in 20 infants, of whom 10 developed confirmed infections, primarily purulent conjunctivitis. Using a cumulative sum (CUSUM) control chart applied to monthly acquisition counts from January 2021 to December 2025, an outbreak was identified between December 2023 and May 2024. Whilst the detection rate during the non-outbreak phase was 1.17 patients per month, it rose to 3.33 patients per month during the outbreak ( p < 0.001). The number of infections was also significantly higher, with 1.67 infections per month within the outbreak period compared to 0.30 infections per month ( p < 0.001). The median gestational age was lower in patients with a confirmed infection than in patients with colonization only (214.5 vs. 243.5 days, p = 0.029). Four isolates from three affected children had undergone detailed typing. All isolates exhibited the same spa - (t328), ST- (15), and CT- (38152) types. In the cgMLST analysis, these isolates form a single cluster. All four isolates harbored the eta gene, suggesting the potential for expression of exfoliative toxin A. Following implementation of a bundle of enhanced infection-control measures, no further outbreak-associated detections occurred. As part of this response, and because systematic identifiable staff screening was restricted by data-protection requirements, all staff members were offered voluntary anonymous screening for nasal S. aureus colonization and, where appropriate, access to mupirocin decolonization. Although the contribution of individual interventions cannot be determined, the temporal association suggests that the combined infection-control measures likely contributed to containment of the outbreak. Our report shows that antibiotic susceptible pathogens can cause outbreaks in NICUs. Surveillance that also includes susceptible pathogens may facilitate the detection and epidemiological assessment of suspicious clusters.
SN - 1664-302X
ER -