Abstract
The aim of current study was to examine clonal structure and genetic profile of invasive Staphylococcus aureus isolates recovered from infants and children treated at the Jagiellonian University Children’s Hospital of Krakow, Poland. The 107 invasive S. aureus isolates, collected between February 2012 and August 2014, were analysed retrospectively. Antimicrobial susceptibility testing, spa typing and DNA microarray analysis were performed to determine clonal distribution, diversity and gene content in regard to patients characteristics. In total, 107 isolates were recovered from 88 patients with clinical symptoms of invasive bacterial infection. The final set of 92 non-duplicate samples included 38 MRSA isolates. Additionally, a set of 54 S. aureus isolates collected during epidemiological screening was genotyped and analysed. There were 72 healthcare-associated (HCA) and 20 community-onset (CO) infection events caused by 33 and 5 MRSA isolates, respectively. The majority of isolates were affiliated with the major European clonal complexes CC5 (t003, spa-CC 002), CC45 (spa-CC 015), CC7 or CC15 (t084, t091, spa-CC 084). Two epidemic clones (CC5-MRSA-II or CC45-MRSA-IV) dominated among MRSA isolates, while MSSA population contained 15 different CCs. The epidemiological screening isolates belonged to similar genetic lineages as those collected from invasive infection cases. The HCA infection events, spa types t003, t2642 or CC5 were significantly associated with infections occurring in neonates and children under 5 years of age. Moreover, carriage of several genetic markers, including erm(A), sea (N315), egc-cluster, chp was significantly higher in isolates obtained from children in this age group. The spa types t091 and t008 were underrepresented among patients aged 5 years or younger, whereas spa type t008, CC8 and presence of splE was associated with infection in children aged 10 years or older. The HCA-MRSA strains were most frequently found in children under 5 years, although the majority of invasive infections was associated with MSSA strains. Moreover, an association between age group of children from the study population and a specific strain genotype (spa type, clonal complex or genetic content) was observed among the patients.
Highlights
Staphylococcus aureus is one of major human pathogens, associated with wide spectrum of localized or systemic infections, including bacteremia or sepsis
The collection comprised 107 S. aureus isolates recovered from 88 paediatric patients with symptoms of invasive infection and 54 epidemiological screening isolates
Staphylococcus aureus is one of the most common opportunistic pathogens in adult and paediatric populations acquired in both community or hospital settings [3,7,18,19,20]
Summary
Staphylococcus aureus is one of major human pathogens, associated with wide spectrum of localized or systemic infections, including bacteremia or sepsis. In Sweden, S. aureus was the most common pathogen found in blood samples from children undergoing infection, irrespectively of underlying risk factors [3]. Both MRSA and methicillin susceptible (MSSA) S. aureus strains are responsible for only 1% of all-cause bacteremia and meningitis in infants, observed mortality rates are high and amount to 26% and 24%, respectively [1]. Treatment of S. aureus infections is challenging due to its multi-resistant profile and ability to produce a wide range of virulence factors, including staphylococcal enterotoxins, proteases, leukocidins, proteins associated with immune-evasion or adhesion [9,10]. The relationships between age and epidemiological classification of infection event, resistance profile, corresponding strain spa type or clonal complex (CC), were investigated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
