Differences Between Methicillin-susceptible Versus Methicillin-resistant Staphylococcus aureus Infections in Pediatrics: Multicenter Cohort Study Conducted in Bogotá, Colombia, 2014-2018

Outcome of extracorporeal membrane oxygenation support among children with methicillin-resistant Staphylococcus aureus infection: A single-center experience

Introduction: The use of extracorporeal membrane oxygenation (ECMO) in children continues to increase nationally, including patients with methicillin-resistant Staphylococcus aureus (MRSA) infection. Survival of pediatric patients with MRSA sepsis has not improved over the last 20 years. We sought to review our institutional experience and outcomes of ECMO support among children with MRSA infection.Methods: Children aged 0-19 years who received ECMO support from October 2014 to June 2021 were reviewed retrospectively. Patients with laboratory confirmed MRSA infections were identified.Results: Out of 88 unique pediatric patients requiring ECMO support, eight patients had documented MRSA infections. The duration of mechanical ventilation prior to ECMO initiation was an average of seven days (range 0.7 to 21.8 days). The median ECMO duration was 648.1 h (range 15.5 to 1580.5 h). Five patients were successfully decannulated; however, only two patients survived to discharge. The two surviving patients were both cannulated via VV-ECMO. Mechanical ventilation prior to ECMO was 4.5 and 21.8 days in these cases with run durations of 18.9 and 29.9 days, respectively.Conclusions: Our institutional survival of patients with MRSA on ECMO is lower than what has been reported in recent database studies, but notably, 62.5% were successfully decannulated. While both surviving patients were supported with VV-ECMO, there was no other clear trend in factors that contributed to survival. MRSA continues to be a source of significant morbidity and mortality among pediatric patients. On-going investigation of outcomes and factors contributing to survival in patients with MRSA infection on ECMO is warranted.

Epidemiological and microbiological characteristics of S. aureus pediatric infections in Colombia 2018-2021, a national multicenter study (Staphylored Colombia)

Background

Staphylococcus aureus infections are a significant cause of morbidity and mortality in pediatric populations worldwide. The Staphylo Research Network conducted an extensive study on pediatric patients across Colombia from 2018 to 2021. The aim of this study was to describe the epidemiological and microbiological characteristics of S. aureus in this patient group.

Methods

We analyzed S. aureus isolates from WHONET-reporting centers. An "event" was a positive culture isolation in a previously negative individual after 2 weeks. We studied center characteristics, age distribution, infection type, and antibiotic susceptibilities, comparing methicillin sensitive (MSSA) and resistant S. aureus (MRSA) isolates.

Results

Isolates from 20 centers across 7 Colombian cities were included. Most centers (80%) served both adults and children, with 55% offering oncology services and 85% having a PICU. We registered 8,157 S. aureus culture isolations from 5,384 events (3,345 MSSA and 1,961 MRSA) in 4,821 patients, with a median age of 5 years. Blood (26.2%) and skin/soft tissue (18.6%) were the most common infection sources. Most isolates per event remained susceptible to oxacillin (63.2%), clindamycin (94.3%), and TMP-SMX (98.3%). MRSA prevalence varied by city (<0.001), with slightly higher rates observed in exclusively pediatric hospitals. In contrast, the MRSA rate was somewhat lower in centers with Antimicrobial Stewardship Program (ASP). MRSA was predominantly isolated from osteoarticular infections and multiple foci, while MSSA was more frequently associated with recurrent infections compared to MRSA.

Conclusions

This is the largest study of pediatric S. aureus infections in Colombia. We found MSSA predominance, but resistance have important regional variations. S. aureus remains susceptible to other commonly used antibiotics such as TMP-SMX and clindamycin. Ongoing monitoring of S. aureus infections is vital for understanding their behavior in children. Prospective studies within the Staphylored LATAM are underway for a more comprehensive clinical and genetic characterization.

Correlation between the results of cultures and the molecular BIOFIRE® joint infection panel in a cohort of pediatric patients with bone and joint infections in Bogotá, Colombia

Introduction

Bone and Joint Infections (BJI) have high morbidity. Methicillin resistant Staphylococcus aureus (MRSA) has increased. Culture-based diagnosis has difficult to recovering fastidious bacteria and detecting polymicrobial infections, molecular methods offer a promising improvement for the diagnosis of BJI with reduced time to result. The aim of the study was to determine the correlation between culture results and the Biofire joint infection panel (BJIP) in a cohort of pediatric patients with BJI.

Materials and methods

Descriptive study. Patients admitted with probable o confirmed BJI between July 1, 2019 and February 28, 2021 at HOMI. Blood cultures, synovial and bone fluid samples were taken. Samples were kept at -70 °C. On September 2022, the panel was performed.

Results

32 patients were included. The average age was 83m (RIQ: 32-145). 23 (71.8%) patients had a positive culture. The most frequent microorganism were S. aureus 19 (83%), 11/19 (57.9%) Staphylococci isolates were MRSA. 24/32 (75%) were positive by panel, 20 positive detections were concordant with culture, there were 6 additional isolates by panel (2 S. aureus, 2 S. pyogenes, 1 K. kingae and 1 C. albicans), three microorganisms were isolated in culture but not in the panel. (2 S. aureus and 1 S. agalactiae). Two patients with coinfection were detected. All MRSA were detected by culture and panel. In 26 (81.3%) patients the etiology was documented by any method.

Conclusion

These results showed a moderate level of agreement between BJIP and culture (κ = 0.47). The panel allowed the detection of fastidious bacteria including K. kingae and polymicrobial samples. There was a very good level of agreement between the panel and culture for the MRSA detection (κ = 1).

[Prevalence and risk factors for methicillin-resistant Staphylococcus aureus infection in children]

OBJECTIVE

The objectives of this work were to know the prevalence of methicillin-resistant S. aureus (MRSA) infections in the paediatric population of our health department, to describe the risk factors for infection by MRSA compared to those produced by methicillin-susceptible S. aureus (MSSA) and to know the antibiotic sensitivity profile of MRSA and MSSA isolates.

METHODS

A retrospective, descriptive and analytical study of infections produced by MRSA versus those produced by MSSA was carried out during the years 2014 to 2018. Risk factors for MRSA infection were studied using a binary logistic regression model.

RESULTS

162 patients with S. aureus infections were identified. Of these, 25 (15.4%) were MRSA. The highest percentages of MRSA infection occurred among children who required hospital admission (23.4%). In the univariate analysis the need of hospital admission, antibiotic treatment in the last 3 months, the kind of infection and past MRSA infection or colonisation reached statistical significance. However, only the need of hospital admission and antibiotic treatment in the last 3 months maintained statistical significance in the binary logistic regression model. Correct antibiotic treatment was only prescribed in 26.7% of the MRSA infection cases admitted to the hospital.

CONCLUSIONS

Our results suggest the need to review empirical local treatment regimen using drugs active against MRSA in infections of probable staphylococcal origin admitted to the hospital, especially if they have received antibiotic treatment in the last 3 months.

Detailed Insight into Photocatalytic Inactivation of Pathogenic Bacteria in the Presence of Visible-Light-Active Multicomponent Photocatalysts

The use of heterogeneous photocatalysis in biologically contaminated water purification processes still requires the development of materials active in visible light, preferably in the form of thin films. Herein, we report nanotube structures made of TiO2/Ag2O/Au0, TiO2/Ag2O/PtOx, TiO2/Cu2O/Au0, and TiO2/Cu2O/PtOx obtained via one-step anodic oxidation of the titanium-based alloys (Ti94Ag5Au1, Ti94Cu5Pt1, Ti94Cu5Au1, and Ti94Ag5Pt1) possessing high visible light activity in the inactivation process of methicillin-susceptible S. aureus and other pathogenic bacteria-E. coli, Clostridium sp., and K. oxytoca. In the samples made from Ti-based alloys, metal/metal oxide nanoparticles were formed, which were located on the surface and inside the walls of the NTs. The obtained results showed that oxygen species produced at the surface of irradiated photocatalysts and the presence of copper and silver species in the photoactive layers both contributed to the inactivation of bacteria. Photocatalytic inactivation of E. coli, S. aureus, and Clostridium sp. was confirmed via TEM imaging of bacterium cell destruction and the detection of CO2 as a result of bacteria cell mineralization for the most active sample. These results suggest that the membrane ruptures as a result of the attack of active oxygen species, and then, both the membrane and the contents are mineralized to CO2.

Significant increase in the prevalence of Panton-Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus, particularly the USA300 variant ΨUSA300, in the Japanese community

IMPORTANCE

USA300 is an MRSA clone producing PVL, a toxin associated with SSTIs. ΨUSA300 is a USA300 variant recently identified in Japan by Takadama et al. (15). Here, we found that the prevalence rate of PVL-positive MRSA in S. aureus was elevated in the Japanese community, and ΨUSA300 accounted for most of them. ΨUSA300 strains have been isolated from several areas in Japan and were associated with deep-seated SSTIs. This study highlighted the emerging threat posed by ΨUSA300 in Japan.

Analysis of the Trends of Methicillin-Resistant Staphylococcus aureus in Gauteng Public Hospitals from 2009 to 2018

Most investigations into the distribution of methicillin resistant Staphylococcus aureus (MRSA) have focused exclusively on bloodborne infections within individual health care institutions for shorter time periods. This has limited the analysis of a community-spread pathogen to snapshots within the hospital domain. Therefore, in this study we determined the demographic and geographical patterns of MRSA infections and their fluctuation in 10 years within all public hospitals in Gauteng, South Africa. A retrospective analysis of S. aureus samples was done by deduplicating samples in two groups. The sample groups were placed into subsets with respect to demographic and geographical fields and compared across the studied period. Logistic regression was utilized to determine odds ratios for resistant infections in univariate and multivariable configurations. A total of 66,071 unique infectious events were identified from the 148,065 samples received over a 10-year period, out of which 14,356 were identified as bacteremia. MRSA bacteremia rates in Gauteng peaked in 2015 and have since decreased. Within Gauteng, metropolitan areas have the greatest burden of MRSA with children under 5 years of age and males being most affected. Medical wards have the highest S. aureus bacteremia rates, while intensive care units have the highest MRSA bacteremia rates. Patient age, admitting ward, and geographical district are the most important associated factors of resistance. MRSA acquisition rates have shown tremendous growth since 2009 but have since spiked and subsequently decreased. This may be due to the initiation of the National Guidelines on Antimicrobial Stewardship and Infectious Disease Surveillance. Further studies to determine the trajectory of infections are required to support these claims. IMPORTANCE S. aureus is the leading cause of a variety of devastating clinical conditions, including infective endocarditis, bacteremia, and pleuropulmonary infections. It is an important pathogen responsible for substantial morbidity and mortality. MRSA is a variant of interest originally responsible for difficult to treat hospital-acquired infections that has since achieved community spread throughout the world. Most investigations into the distribution of MRSA have focused exclusively on bloodborne infections within individual health care institutions for shorter periods. This has limited the analysis of a community-spread pathogen to snapshots within the hospital domain. This study sought to determine the demographic and geographical patterns of MRSA infections as well as how these have fluctuated over time within all public hospitals. This will also help in understanding the epidemiology and resistance trends of S. aureus, which will help clinicians to understand the clinical prospective and policy makers to design guidelines and strategies for treating such infections.

Staphylococcus aureus causes aberrant epidermal lipid composition and skin barrier dysfunction

BACKGROUND

Staphylococcus (S) aureus colonization is known to cause skin barrier disruption in atopic dermatitis (AD) patients. However, it has not been studied how S. aureus induces aberrant epidermal lipid composition and skin barrier dysfunction.

METHODS

Skin tape strips (STS) and swabs were obtained from 24 children with AD (6.0 ± 4.4 years) and 16 healthy children (7.0 ± 4.5 years). Lipidomic analysis of STS samples was performed by mass spectrometry. Skin levels of methicillin-sensitive and methicillin-resistant S. aureus (MSSA and MRSA) were evaluated. The effects of MSSA and MRSA were evaluated in primary human keratinocytes (HEKs) and organotypic skin cultures.

RESULTS

AD and organotypic skin colonized with MRSA significantly increased the proportion of lipid species with nonhydroxy fatty acid sphingosine ceramide with palmitic acid ([N-16:0 NS-CER], sphingomyelins [16:0-18:0 SM]), and lysophosphatidylcholines [16:0-18:0 LPC], but significantly reduced the proportion of corresponding very long-chain fatty acids (VLCFAs) species (C22-28) compared to the skin without S. aureus colonization. Significantly increased transepidermal water loss (TEWL) was found in MRSA-colonized AD skin. S. aureus indirectly through interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and IL-33 inhibited expression of fatty acid elongase enzymes (ELOVL3 and ELOVL4) in HEKs. ELOVL inhibition was more pronounced by MRSA and resulted in TEWL increase in organotypic skin.

CONCLUSION

Aberrant skin lipid profiles and barrier dysfunction are associated with S. aureus colonization in AD patients. These effects are attributed to the inhibition of ELOVLs by S. aureus-induced IL-1β, TNF-α, IL-6, and IL-33 seen in keratinocyte models and are more prominent in MRSA than MSSA.

Efficacy of Vaporized Hydrogen Peroxide Combined with Silver Ions against Multidrug-Resistant Gram-Negative and Gram-Positive Clinical Isolates

Antimicrobial resistance (AMR) is a serious public health problem that results in high morbidity and mortality rates. In particular, multidrug-resistant (MDR) strains circulating in hospital settings pose a major threat as they are associated with serious nosocomial infections. Therefore, regular cleaning and disinfection procedures, usually using chemical disinfectants, must be implemented in these facilities. Hydrogen peroxide (HP)-based disinfectants have proven high microbicidal activity and several comparative advantages over conventional disinfectants. We assessed the in vitro biocidal activity of an 8% HP solution combined with 30 mg/L silver ions (HP + Ag) against MDR clinical isolates of Klebsiella pneumoniae (MDRKp) and Pseudomonas aeruginosa (MDRPa), and methicillin-resistant Staphylococcus aureus (MRSA). Accordingly, the in vitro antibacterial activity was determined using the macrodilution method, and the efficacy was determined for 30 min in terms of (1) activity on bacteria in suspension and (2) activity on surfaces using vaporized HP + Ag on a 20 cm2 stainless steel surface. A strong bactericidal effect of HP + Ag was observed against MDRKp, MDRPa, and MRSA strains, with minimum inhibitory concentrations and minimum bactericidal concentrations between 362.5 and 5800 mg/L. A strong effect was observed during the 30 min of HP + Ag exposure to the resistant clinical isolates, with over 4-Log10 reduction in CFUs. Regarding the efficacy of the disinfectant on surfaces, bacterial load reductions of >99% were observed. These results suggest that HP + Ag is potentially useful as an effective disinfectant for decontaminating surfaces in hospital settings suspected of contamination with MDR bacteria.