UNASSIGNED: Both healthcare-associated and community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are relevant in children. The objective of our study was to evaluate their impact in a pediatric hospital in southern Brazil.
UNASSIGNED: Data from patients under 18 years of age with S. aureus infections between January 2013 and December 2020 were retrospectively analyzed. Data were collected regarding infection site, infection type (community-acquired or healthcare-associated), susceptibility to oxacillin [methicillin-susceptible S. aureus (MSSA) or MRSA] and other antimicrobials. We analyzed the evolution of the susceptibility rates for the isolates over this period.
UNASSIGNED: A total of 563 patients were included, among whom the prevalences of community- and hospital-acquired MRSA infections were 46.1% and 8.1%, respectively. No significant change occurred in these prevalences over the study period. In community-acquired infections, MSSA was significantly more associated with osteoarticular infections and MRSA was more associated with respiratory and intra-abdominal infections. In healthcare-associated infections, there was an association between MSSA and primary bloodstream infections and between MRSA, skin/soft tissue infections, and respiratory infections. Community-acquired MRSA were highly susceptible to trimethoprim-sulfamethoxazole (96.1%), clindamycin (88.4%), and doxycycline (99.0%).
UNASSIGNED: Our study draws attention to the high rates of MRSA in community-acquired staphylococcal infections in this population, indicating a need to review initial protocols for severe staphylococcal infections according to local epidemiology.

MRSA (Methicillin-resistant Staphylococcus aureus) is the second-leading cause of deaths by antibiotic-resistant bacteria globally, with more than 100,000 attributable deaths annually. Despite the high urgency to develop a vaccine to control this pathogen, all clinical trials with pre-clinically effective candidates failed so far. The recent development of \"humanized\" mice might help to edge the pre-clinical evaluation closer to the clinical situation and thus close this gap. We infected humanized NSG mice (huNSG: (NOD)-scid IL2Rγ null mice engrafted with human CD34+ hematopoietic stem cells) locally with S. aureus USA300 LAC* lux into the thigh muscle in order to investigate the human immune response to acute and chronic infection. These mice proved not only to be more susceptible to MRSA infection than wild-type or \"murinized\" mice, but displayed furthermore inferior survival and signs of systemic infection in an otherwise localized infection model. The rate of humanization correlated directly with the severity of disease and survival of the mice. Human and murine cytokine levels in blood and at the primary site of infection were strongly elevated in huNSG mice compared to all control groups. And importantly, differences in human and murine immune cell lineages surfaced during the infection, with human monocyte and B cell numbers in blood and bone marrow being significantly reduced at the later time point of infection. Murine monocytes in contrast behaved conversely by increasing cell numbers. This study demonstrates significant differences in the in vivo behavior of human and murine cells towards S. aureus infection, which might help to sharpen the translational potential of pre-clinical models for future therapeutic approaches.

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Using computerized time-stamps, we compared the turnaround-times (TAT) for urine samples and screening ESwabs of MRSA, VRE, and ESBL carriage in the bacteriology laboratory of Geneva University Hospitals between January and December 2017 (period preceding the implementation of the WASPLabTM) with the same specimen types analyzed between January and December 2019 (period after the implementation of the automation). During both 1-year periods, a total of 98\'380 specimens were analyzed (48\'158 in 2017 vs. 50\'222 in 2019). On the WASPLabTM, all culture plates were imaged at defined intervals each day of incubation, but the processing of the cultures (i.e., pathogen identification and antimicrobial susceptibility testing) was only performed during day shift hours (~8:00 A.M. to 4:30 P.M.). The median TAT for negative reports decreased by almost half for urine samples from 52.1 (2017) to 28.3 h (2019) (p < 0.001), and for MRSA screening specimens from 50.7 to 26.3 h (p < 0.001). The difference in median TAT for negative reports was less pronounced for screening of ESBL (50.2 vs. 43.0 h) (p < 0.001) and VRE (50.6 vs. 45.7 h) (p < 0.001). Despite a trend toward shorter result delivery for positive samples, there was no significant change in the median TAT. These results suggest that TAT for negative samples immediately benefit from automation, whereas TAT for positive samples also depend on the laboratory hours of operation and daily human resource management.