Invasive community-onset gram-positive infections from July 2018 through December 2022 at 2 children\u27s hospitals

BACKGROUND: Invasive infections caused by METHODS: Cases of iGAS, IPD, and I-CO-SA infections were identified prospectively and retrospectively at 2 large US children\u27s hospitals by positive cultures from July 2018 through December 2022. Admission data were used to estimate frequency. For comparison, rates of respiratory syncytial virus (RSV), influenza, and SARS-CoV-2 were estimated by the number of positive viral test results at each institution. RESULTS: I-CO-SA infections showed little variation in the study period. Rates of iGAS infection and IPD decreased by 46% and 44%, respectively, from 2019 to 2020, coinciding with a substantial decrease in RSV and influenza. In 2022, RSV and influenza infection rates increased to prepandemic winter season rates, coinciding with a return to prepandemic rates of IPD (225% increase from 2021 to 2022) and a surge above prepandemic rates of iGAS infections (543% increase from 2021 to 2022). CONCLUSIONS: The COVID-19 pandemic had an unexpected influence on IPD and iGAS infections that was temporally related to changes in rates of viral infections

Rapid detection of Staphylococcus aureus Panton-Valentine leukocidin in clinical specimens by enzyme-linked immunosorbent assay and immunochromatographic tests

10.1128/JCM.02274-09Journal of Clinical Microbiology4841384-139

A Field Guide to Pandemic, Epidemic and Sporadic Clones of Methicillin-Resistant Staphylococcus aureus

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements

A Field Guide to Pandemic, Epidemic and Sporadic Clones of Methicillin-Resistant Staphylococcus aureus

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements

Clonality of Streptococcus pneumoniae Serotype 1 Isolates from Pediatric Patients in the United States

We compared Streptococcus pneumoniae serotype 1 isolates causing disease among children in six geographic regions of the United States to determine genetic relatedness. Genomic fingerprints were determined by repetitive element polymorphism PCR (Rep-PCR). Multilocus sequence type characterization was performed on selected isolates. Four different genomic banding patterns were identified by Rep-PCR. One profile (clone 1) was predominant and matched sequence type 227

Pediatric Antibody Response to Community-Acquired Staphylococcus aureus Infection Is Directed to Panton-Valentine Leukocidin▿

We examined the antibody responses of pediatric patients infected with community-associated Staphylococcus aureus isolates. The data show that patients infected with Panton-Valentine leukocidin (PVL)-positive strains developed a dominant immunoglobulin G anti-PVL antibody response that correlates with markers of inflammation

Vancomycin MICs for Staphylococcus aureus Vary by Detection Method and Have Subtly Increased in a Pediatric Population Since 2005▿

Vancomycin MICs for Staphylococcus aureus isolates in a pediatric hospital with a high rate of staphylococcal infections were examined for any increase over a 7-year period. A broth microdilution scheme allowed direct comparison of the MICs generated by this method to MICs generated by Etest. MICs generated by both methods were determined with the same inoculum suspension. One hundred sixty-five S. aureus isolates were selected on the basis of the patients having been bacteremic or having received vancomycin as the definitive therapy for their infections. Of the 165 isolates, 117 were methicillin-resistant S. aureus and 48 were methicillin-susceptible S. aureus. Forty-seven were acquired in the hospital (nosocomial), 56 were community acquired, and 62 were community onset-health care associated. All but one isolate tested by broth microdilution had MICs of <1.0 μg/ml, while 96% of these same isolates tested by Etest had MICs of ≥1 μg/ml. A significant increase in MICs that occurred after study year 4 (2004 to 2005) was demonstrated by the Etest (P < 0.00007) but not by broth microdilution. MICs were not different for isolates of community or health care origin, regardless of methodology. The proportion of isolates with Etest MICs of <1 and ≥1 μg/ml between children with bacteremia for ≤5 days and >5 days (P = 0.3) was not different. We conclude that MICs for pediatric isolates have increased slightly since 2005 and therapeutic decisions based on vancomycin MICs need to be made by considering the methodology used

Adhesin genes and biofilm formation among pediatric Staphylococcus aureus isolates from implant-associated infections.

BackgroundMicrobial surface component recognizing adhesive matrix molecules (MSCRAMMs) facilitate Staphylococcus aureus adherence to host tissue. We hypothesized that S. aureus isolates from implant-associated infections (IAIs) would differ in MSCRAMM profile and biofilm formation in vitro compared to skin and soft tissue infection (SSTI) isolates.MethodsPediatric patients and their isolates were identified retrospectively. IAI and SSTI isolates were matched (1:4). Pulsed field gel electrophoresis was performed to group isolates as USA300 vs. non-USA300. Whole genome sequencing was performed and raw sequence data were interrogated for presence of MSCRAMMs (clfA, clfB, cna, ebh, efb, fnbpA, fnbpB, isdA, isdB, sdrC, sdrD, sdrE), biofilm-associated (icaA,D,B,C), and Panton-Valentine leukocidin (lukSF-PV) genes, accessory gene regulator group, and multilocus sequence types. In vitro biofilm formation was assessed for 47 IAI and 47 SSTI isolates using a microtiter plate assay. Conditional logistic regression was performed for analysis of matched data (STATA11, College Station, TX).ResultsForty-seven IAI and 188 SSTI isolates were studied. IAI isolates were more often methicillin susceptible S. aureus and non-USA300 vs. SSTI isolates [34 (72%) vs. 79 (42%), p = 0.001 and 38 (81%) vs. 57 (30%) p ConclusionsS. aureus IAI isolates were significantly more likely to be MSSA and non-USA300 than SSTI isolates. Carriage of MSCRAMMs and biofilm formation did not differ significantly between isolates. Evaluation of genetic polymorphisms and gene expression profiles are needed to further delineate the role of adhesins in the pathogenesis of IAIs

Mupirocin Resistance in Staphylococcus aureus Causing Recurrent Skin and Soft Tissue Infections in Children▿

Staphylococcus aureus resistance to mupirocin is often caused by acquisition of a novel isoleucyl-tRNA synthetase encoded on the plasmid gene mupA. We tested S. aureus isolates from children at Texas Children's Hospital with recurrent skin and soft tissue infections for mupirocin resistance and mupA. Of 136 isolates, 20 were resistant to mupirocin (14.7%). Fifteen isolates (11%) carried mupA, and the gene was more common in methicillin-susceptible S. aureus (21.4%) than methicillin-resistant S. aureus (8.3%; P = 0.03). Seven of 20 mupirocin-resistant isolates displayed clindamycin resistance

Molecular Epidemiology of Pediatric Pneumococcal Empyema from 2001 to 2007 in Utah▿

Utah had a high rate of pediatric pneumococcal empyema (PPE) prior to licensure of the pneumococcal conjugate vaccine (PCV-7) in 2000. The majority (62%) of PPE cases was due to nonvaccine serotypes, primarily Streptococcus pneumoniae serotype 1, multilocus sequence type (MLST) 227. PPE in Utah children has increased over the last decade. It is unclear whether the increase was due to serotype replacement or switch. In this study, we describe the incidence and molecular epidemiology of PPE by MLST in Utah children after the licensure of PCV-7. Empyema rates increased from 8.5/100,000 children in the state of Utah in 2001 to 12.5/100,000 children in 2007 (P = 0.006). Ninety-eight percent was due to nonvaccine serotypes (P < 0.001 when compared to the pre-PCV-7 period). PPE was primarily due to serotypes 1, 3, 19A, and 7F, with MLST demonstrating sequence types (ST) that were commonly present in the United States prior to licensure of PCV-7. Serotype switch was not documented. Replacement disease with common ST of serotypes 1,3, 7F, and 19A rather than serotype switch was responsible for the increase in PPE in Utah children