Identification and characterization of Staphylococcus argenteus from Indonesia.

BACKGROUND: In 2015, Staphylococcus argenteus was reported for the first time as a novel species of the Staphylococcus aureus complex. While S. argenteus has been found in many countries, its presence in Indonesia has not been reported yet. Our aim is to confirm S. argenteus presence in Indonesia, describe its characteristics and analyze its genomic diversity. METHODS: The S. aureus isolates used in this study were collected from patients with skin and soft tissue infections in Indonesia, between July 2009 to February 2010. Randomly selected isolates were recultured from -80 C° stocks and analyzed using matrix-assisted laser desorption/ionization - time of flight (MALDI-TOF). Isolates identified as S. argenteus, S. roterodami, or S. schweitzeri and S. aureus with a low score in the MALDI-TOF analysis were analyzed by a real-time PCR targeting the nucA gene able to identify true S. argenteus. Isolates identified as S. argenteus were further characterized by whole genome sequencing. Vitek®2 (bioMérieux) was used for antimicrobial susceptibility testing. RESULTS: Fifteen isolates were identified as S. argenteus, with the majority belonging to ST2250. Two pairs of isolates proved to be identical by core genome multilocus sequence typing analysis. Most isolates were susceptible to all antibiotics tested, except for seven isolates (46.7 %) that were resistant to benzylpenicillin, and one isolate was resistant to tetracycline (6.7 %). The presence of resistance genes blaZ and tet(45) correlated with these findings. Notably, the sey enterotoxin gene was prevalent in 80 % of the isolates. Other virulence factor genes were less prevalent. Plasmid replicon types in S. argenteus were also known to S. aureus. CONCLUSION: Our study reveals the occurrence of S. argenteus in Indonesia. The diversity within Indonesian S. argenteus matches the global diversity of S. argenteus. Identical isolates between patients indicate potential transmission events. A lower prevalence of a broad panel of virulence factors suggests that S. argenteus is less virulent than S. aureus.

Dynamics of Staphylococcus aureus in patients and the hospital environment in a tertiary care hospital in the Netherlands.

BACKGROUND: The dynamics of Staphylococcus aureus in patients and the hospital environment are relatively unknown. We studied these dynamics in a tertiary care hospital in the Netherlands. METHODS: Nasal samples were taken from adult patients at admission and discharge. Isolates cultured from clinical samples taken before and during hospitalization from these patients were included. Environmental samples of patient rooms were taken over a three-year period. Finally, isolates from clinical samples from patients with an epidemiological link to S. aureus positive rooms were included. Staphylococcal protein A (spa) typing was performed. RESULTS: Nasal samples were taken from 673 patients. One hundred eighteen (17.5%) were positive at admission and discharge, 15 (2.2%) patients acquired S. aureus during hospitalization. Nineteen patients had a positive clinical sample during hospitalization, 15.9% of the S. aureus were considered as from an exogenous source. One hundred and forty (2.8%) environmental samples were S. aureus positive. No persistent contamination of surfaces was observed. Isolates were highly diverse: spa typing was performed for 893 isolates, identifying 278 different spa types, 161 of these spa types were observed only once. CONCLUSION: Limited transmission could be identified between patients and the hospital environment, and from patient-to-patient. Exogenous acquisition was assumed to occur in 15% of clinical samples. Environmental contamination was infrequent, temporarily, and coincided with the strain from the patient admitted to the room at that time. MRSA was rare and not found in the environment.