Molecular epidemiology of methicillin-susceptible Staphylococcus aureus in infants in a neonatal intensive care unit

Abstract

Objective: To investigate the molecular epidemiology of methicillin-susceptible Staphylococcus aureus (MSSA) in infants in a neonatal intensive care unit (NICU) using whole-genome sequencing. Design: Investigation of MSSA epidemiology in a NICU. Setting: Single-center, level IV NICU. Methods: Universal S. aureus screening was done using a single swab obtained from the anterior nares, axilla, and groin area of infants in the NICU on a weekly basis. Core genome multilocus sequence type (cgMLST) analysis was performed on MSSA isolates detected over 1 year (2018–2019). Results: In total, 68 MSSA-colonized infants were identified, and cgMLSTs of 67 MSSA isolates were analyzed. Overall, we identified 11 cgMLST isolate groups comprising 39 isolates (58%), with group sizes ranging from 2 to 10 isolates, and 28 isolates (42%) were unrelated to each other or any of the isolate groups. Cases of infants colonized by MSSA were scattered throughout the 1-year study period, and isolates belonging to the same cgMLST group were typically detected contemporaneously, over a few weeks or a few months. Overall, 13 infants (19.7%) developed MSSA infections: bacteremia (n = 3), wound infection (n = 5), conjunctivitis (n = 4), and cellulitis (n = 1). We detected no association between these clinically manifest infections and specific cgMLST groups. Conclusions: Although MSSA isolates in infants in a NICU showed high diversity, most were related to other isolates, albeit within small groups. cgMLST facilitates an understanding of the complex transmission dynamics of MSSA in NICUs, and these data can be used to inform better control strategies.

A Combined Phenotypic-Genotypic Predictive Algorithm for In Vitro Detection of Bicarbonate: β-Lactam Sensitization among Methicillin-Resistant Staphylococcus aureus (MRSA)

“…As WGS and other genotyping methods become faster, cheaper, and more widespread, the identification of specific sequences and genomic markers associated with antibiotic-resistant and antibiotic-susceptible phenotypes will undoubtedly be employed by many clinical microbiology laboratories. Today, WGS is considered the state-of-the-art method for clonality testing of S. aureus , having replaced outdated methods such as pulsed-field gel electrophoresis [ 41 , 42 , 43 , 44 ].…”

Antimicrobial and biocide resistance in Staphylococcus aureus: genomic features, decontamination strategies, and the role of S. aureus complex-related species, with a focus on ready-to-eat food and food-contact surfaces

“…Since the development of the S. aureus cgMLST scheme (Leopold et al, 2014), a few dozen papers have been published on the cgMLST for epidemiological study. The majority of these are associated with CA-MRSA or MSSA outbreaks (Park et al, 2017;Madigan et al, 2018;Cheng et al, 2019;Cho et al, 2020;Slingerland et al, 2020). Konstantinovski et al (2021) used this method to monitor the transmission of oxacillin-resistant SA in hospital environments, while Kinnevey et al (2021) studied the transmission of MRSA in healthcare workers, patients, and environments in non-outbreak settings.…”