Community-acquired Methicillin-resistant Staphylococcus Aureus Infections Research Articles

Community-acquired methicillin-resistant Staphylococcus aureus invasive infections: a case series from Central-South Chile

The emergence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections at the end of the 20th century represents a significant shift in the epidemiology of staphylococcal infections and, consequently, their clinical management. There are diverse CA-MRSA clones that are widely spread worldwide, showing differences in their regional dissemination, which has been dynamically changing over time. Although the first CA-MRSA description occurred about 30 years ago, its epidemiology in certain regions, such as South America, has been poorly explored, resulting in a gap in the understanding of the epidemiology of CA-MRSA in under-represented countries/regions. This report describes the first four clinical cases of invasive infections caused by CA-MRSA in a tertiary hospital in the central-southern region of Chile. It also associates the clinical characteristics of the infections with the microbiological and molecular features of the isolates. The four S. aureus isolates belong to sequence type 8, which has been widely described as a cause of community-acquired infections. All of them presented a wide resistome and virulome. Additionally, in two of them, it was possible to reconstruct the COMER genetic element, present in the USA300-Latin American variant clone. Considering these findings, it is crucial to prepare for a potential increase in invasive CA-MRSA infections in Chile. This would involve enhancing current surveillance systems and maintaining a low threshold of suspicion for these infections among clinicians.

A Bayesian multilevel analysis exploring population-level effects mediating the relationship between area-level poverty and community-acquired Methicillin-resistant Staphylococcus aureus (CA-MRSA) infection across California communities.

Poverty is an often-cited driver of health disparities, and associations between poverty and community-acquired Methicillin-resistant Staphylococcus aureus (CA-MRSA) infection are well documented. However, the pathways through which poverty influences infection have not been thoroughly examined. This project aims to identify mediating variables, or mechanisms, explaining why area-level poverty is associated with CA-MRSA infection in Californians. Bayesian multilevel models accounting for spatial confounding were developed to test whether the association between area-level poverty and CA-MRSA infection is mediated by living in a primary care shortage area (HCSA), living near an adult correctional facility, and residential environmental degradation. The association between area-level poverty and CA-MRSA infection can be partially explained by spatial autocorrelation, living in an HCSA, and environmental degradation in the neighborhood. Combined, the mediators explain approximately 6% of the odds of CA-MRSA infection for individuals living in neighborhoods with high poverty rates and 50% of the statistical association between area-level poverty and CA-MRSA infection. The statistical association between area-level poverty and infection was completely explained by the mediators for individuals living in neighborhoods with low poverty rates.

Molecular Epidemiology of Community-Acquired Methicillin-Resistant Staphylococcus aureus and Clinical Characteristics of Different Sites of Infection.

Since community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized, the molecular epidemiology of CA-MRSA in China has been diverse. It is unclear whether different sites of CA-MRSA infection differ in antimicrobial resistance and clinical characteristics. The purpose of this study was to identify the molecular types, virulence factors and antimicrobial resistance of CA-MRSA strains and to analyze the clinical characteristics of different sites of CA-MRSA infection. 26 CA-MRSA strains were screened from Beijing Chao-Yang Hospital from 2014 to 2022. SCCmec type, MLST type, spa type, Panton-Valentine leukocidin (PVL), hemolysin α (Hla), phenolic soluble regulatory protein α (PSMα), toxic shock syndrome toxin-1 (TSST-1), and enterotoxin (SE) A to E were detected by PCR and gene sequencing. Antimicrobial susceptibility tests and the clinical features of CA-MRSA infection cases were collected for statistical analysis. The predominant type of CA-MRSA was ST59-t437-IV. New non-epidemic types, SCCmec VII, were also found. PVL was seen in 65.4% of CA-MRSA strains and TSST-1 was only be detected in 3.8% of CA-MRSA strain which caused poor prognosis. There were three types of infections: pneumonia (61.5%), infective endocarditis (7.7%), and skin and soft tissue infections (SSTIs) (30.8%). CA-MRSA pneumonia cases were secondary to influenza infection (37.5%). Patients with CA-MRSA-associated infective endocarditis were more likely to have underlying cardiac diseases. Patients with CA-MRSA-associated SSTIs were more likely to have a history of diabetes mellitus, and strains in this group were more susceptible to erythromycin and clindamycin. ST59-t437-IV was the primary CA-MRSA type in our research and in China. We proposed that TSST-1 might be one of the indicators to predict the severity and prognosis of CA-MRSA infection. Different sites of CA-MRSA infection had difference in antibiotics susceptibility testing and underlying diseases of patients. It could provide a new perspective on treating different types of CA-MRSA infection.

Current and emerging drug treatment strategies to tackle invasive community-associated methicillin-resistant Staphylococcus aureus (MRSA) infection: what are the challenges?

ABSTRACT Introduction Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections represent a leading cause of purulent skin and soft tissue infections in some geographical regions. Traditionally, ‘old antibiotics’ such as trimethoprim-sulfamethoxazole, tetracyclines, clindamycin, chloramphenicol,vancomycin, and teicoplanin have been used to treat these infections, but these were often associated with low efficacy and excessive side effects and toxicity, especially nephrotoxicity. Along with the development of new compounds, the last decade has seen substantial improvements in the management of CA-MRSA infections. Areas covered In this review, the authors discuss the current and emerging drug treatment strategies to tackle invasive CA-MRSA infections. Articles reported in this review were selected from through literature searches using the PubMed database. Expert opinion The availability of new drugs showing a potent in vitro activity against CA-MRSA represents a unique opportunity to face the threat of resistance while potentially reducing toxicity. All these compounds represent promising options to enhance our antibiotic armamentarium. However, data regarding the use of these new drugs in real-life studies are limited and their best placement in therapy and in terms of optimization of medical resources and balance of cost-effectiveness requires further investigation.

Community-acquired S. aureus infection in childhood: a multi-center study.

The prevalence of community-acquired methicillin-resistant S. aureus (CA-MRSA) has been increasing worldwide. We aimed to investigate the prevalence of MRSA in community-acquired S. aureus infections, the risk factors for CA-MRSA infection and the clinical features of CA-MRSA. A multi-center study with prospective and retrospective sections was conducted. Patients ≥ 3 months old and ≤18 years of age who were diagnosed with community-acquired S. aureus infections were included in this study and the patients` information were reviewed from the medical and microbiological database of the hospital. A standard question form about living conditions and exposure risk factors was administered to the parents of patients. The CA-MRSA infections were compared with the methicillin-susceptible S. aureus (CAMSSA) infections in terms of the queried risk factors and clinical variables. We identified 334 pediatric patients with S. aureus infection, 58 (17.4%) had an infection with CAMRSA. The refugee rate was higher in the CA-MRSA group. There was no significant difference regarding the exposure risk. The treatment modalities and outcomes were similar. The study was not able to show reliable clinical variables or epidemiological risk factors except for being a refugee for CA-MRSA infections. Empirical antibiotic treatment should therefore be determined according to the local CA-MRSA prevalence in patients presenting with a possible staphylococcus infection.

Methicillin-resistant Staphylococcus aureus contamination of high-touched surfaces in a university campus.

Methicillin-resistant Staphylococcus (MRSA) is a public and occupational health concern, both in community and healthcare settings. In recent years, community-acquired MRSA (CA-MRSA) has emerged as a major causative agent of infections in individuals with no health care exposure or any of the classical risk factors associated with infections. Environmental surfaces frequently touched by hands play a role in the transmission of CA-MRSA, where inanimate objects are considered potential reservoirs and the source of MRSA infections. The purpose of this study was to examine the prevalence of MRSA on environmental surfaces inside a university campus. A total of 1078 high-touch surface samples were collected from door handles, light switches, desks, keyboards and restroom surfaces. MRSA isolates were identified and confirmed by PCR, utilizing the Staph. aureus nuc and mecA genes. Antibiotic resistance profiles were determined using disc diffusion and minimum inhibitory concertation methods. In addition, the ability to form biofilms was investigated by the 96-well plate microdilution technique. PCR assays were performed to detect enterotoxin and antibiotic-resistant genes. The genetic diversity of MRSA was determined through multi-locus sequence typing (MLST), spa and agr typing methods. The overall contamination of Staph. aureus and MRSA was 14.6% (157/1078) and 2.8% (30/1078), respectively. The highest rate of MRSA contamination was detected in restroom sinks and door handles. All MRSA isolates were MDR, with the highest resistance observed was against trimethoprim-sulfamethoxazole. Most MRSA isolates (29/30, 97%) carried at least one gene encoding for staphylococcal enterotoxins (SE), with 10 different SE genotypes were observed. A total of 16 different spa types were detected among the 30 MRSA isolates. Multi-locus sequence typing revealed that 21 MRSA isolates belonged to eight known sequence types (ST), while nine isolates were novel strains. The most detected ST and spa types were ST22 and t223, respectively. Agr types I and III were represented in 28 out of the 30 isolates. The majority of the isolates carried SCCmec type IV, but only one isolate was positive for PVL. Our findings signify the potential of the high-touch surfaces in harbouring and transmitting MRSA to campus staff and students. Thus, the implementation of effective prevention measures outside the healthcare setting is needed to reduce the risk of acquiring CA-MRSA infections. MRSA infections impose a profound economic burden due to illness and productivity loss. The results of this study not only help us to better understand the environmental reservoirs of this pathogen, but also provide information about its transmission pathways and healthcare settings entry routs.

Comparison of virulence-related determinants between the ST59-t437 and ST239-t030 genotypes of methicillin-resistant\xa0Staphylococcus aureus

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen for human infection. Hospital-acquired (HA) and community-acquired (CA) MRSA infections are serious clinical problems worldwide. In this study, we selected typical HA-MRSA strain and CA-MRSA isolates from our previous research and compared their phenotypic and pathogenic abilities both in vitro and in vivo.ResultsST59-t437-SCCmecIVa (YNSA7) and ST59-t437-SCCmecVb (YNSA53) belonged to two prevalent subclones of CA-MRSA, while ST239-t030-SCCmecIII (YNSA163) was an HA-MRSA epidemic clone in Southwest China. ST59-t437 strains demonstrated faster growth ability, higher survival rate resistance to human blood, and more toxin secretion levels and cytotoxicity than ST239-t030. The virulence and regulatory genes of hld, psm-α, RNAIII, agrA, and crtN were highly expressed on CA-MRSA isolates, especially the ST59-t437-SCCmecIVa subclone. However, the ST239-t030 strain had the strongest adhesion and biofilm ability among these MRSA bacteria. Animal experiments revealed the most serious lethal effect on BALB/c mice caused by the YNSA7 strain infection. The survival rates of BALB/c mice infected with the three MRSA strains were 16.7, 50.0 and 100.0% for YNSA7, YNSA53 and YNSA163, respectively. Histopathological analyses of infected animals indicated that the lungs were the most seriously damaged organs, especially for ST59-t437 MRSA. Severe inflammatory reactions, tissue destruction, and massive exudation of inflammatory mediators and cells could be identified in ST59-t437 strain-infected animals.ConclusionsIn general, ST59-t437 strains showed higher pathogenic ability than the ST239-t030 isolate, while ST239-t030 MRSA revealed the features prevalent in hospital settings, specifically for adhesion and biofilm ability.

Clustered cases of infections due to an uncommon methicillin-resistant Staphylococcus aureus originating in a maternity ward

ObjectiveWe aimed to report a community outbreak of an uncommon methicillin-resistant Staphylococcus aureus (MRSA) originating in a maternity ward. Patients and methodsCases were defined by epidemiological, clinical, and microbiological investigations. Microbiological investigations included phenotypic analysis, molecular typing, and whole-genome sequencing. To control the outbreak, we applied both national recommendations to prevent in-hospital transmission and the French High Council for Public Health guidelines on the management of community-acquired MRSA infections. ResultsBetween March and July 2016, seven patients with MRSA infections were identified: six skin and soft tissue infections and one pulmonary infection, including six microbiologically confirmed infections. Infections occurred in community settings, but a link with the same maternity ward was found for all patients. All MRSA strains had a t690 spa type, were tetracycline-resistant, and produced Panton–Valentine leukocidin. All isolates belonged to the sequence type 88 (ST88). ConclusionThis outbreak highlights the largely underestimated risk of healthcare-associated infections in maternity wards. Healthcare workers should be aware of the importance of standard hygiene precautions and use of alcohol-based hand sanitizers for neonates and mothers.

Varicella Hospitalizations and Community-Acquired Methicillin-Resistant Staphylococcus aureus: Seven Years of Active Surveillance

Introduction: In Mexico, universal Varicella vaccination is not part of the National Immunization Program. Community-Acquired Methicillin-Resistant Staphylococcus Aureus (CA-MRSA) infection is increasing worldwide. CA-MRSA infection in children with Varicella has scarcely been reported. Methods and Findings: From January-2012 to December-2018, we performed active surveillance for children <16 years of age hospitalized with Varicella at the Tijuana General Hospital, Mexico. To all patients with suspected bacterial super infection, a culture sampling was conducted. CA-MRSA was described and identified by both in vitro resistance to methicillin and other isoxazolyl penicillins and by identifying the gene mec-A by PCR. A total of 40 patients were enrolled. The median age at admission was 20.5 months (1-190). All but 4 (10%) were previously healthy children. None were vaccinated against Varicella. Cellulitis (with/without abscess) was the leading complication (50%), with 70% CA-MRSA identified in abscesses. Septicemia/bacteremia was present in 10 (25%), blood isolation was confirmed in seven (3 S. aureus (all CA-MRSA), 2 S. pyogenes, 1 S. pneumoniae, 1 E. coli). Conclusion: Hospitalizations by Varicella in our Hospital are not infrequent; they are associated with high morbidity and relatively low mortality. The leading complication was bacterial super infection represented by soft-tissue infections and bacteremia/septicemia mostly due to CA-MRSA. Keywords: Varicella; Methicillin-Resistant Staphylococcus Aureus (MRSA); Community Acquired Methicillin-Resistant Staphylococcus Aureus (CA-MRSA); Varicella vaccine; Antibiotic control

Upward trend in the frequency of community-acquired methicillin-resistant Staphylococcus aureus as a cause of pediatric skin and soft tissue infections over five years: a cross-sectional study.

The increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and its resistance to multiple antibiotics has become a serious challenge since the early 2000s. Especially, community-acquired MRSA (CA-MRSA) infections that appear mainly as skin and soft tissue infections (SSTIs) tend to increase worldwide. The objective of this cross-sectional study was to evaluate the trends in the frequency of SSTIs due to community-acquired S. aureus among children. All children with SSTIs caused by culture positive community-acquired S. aureus during the period from 2013 to 2018 were included in this study. Data of the outpatients were collected from medical records. Annual alteration in frequencies of CA-MRSA and community-acquired methicillin-sensitive S. aureus (CAMSSA) were evaluated. A total of 112 cases was evaluated. Of these, 35 (31.25%) were CA-MRSA. The rates of CA-MRSA had emerged from an increasing annual frequency of 9.5 cases per 10,000 SSTIs as of 2014 to 96.8 cases per 10,000 SSTIs in 2018. The ratio of cases with CA-MRSA to cases with CA-MSSA was 0 - 0.09 in two years of the study period and increased to a maximum ratio of 0.6 - 0.72 in the last two years. Consequently, the frequency of S. aureus in cases with SSTIs was significantly higher in 2016 - 2018 compared to the initial study period within the years of 2013-2015 [p < 0.001, relative risk increase: 7 (2.6-28.7) for CA-MRSA and p=0.002, relative risk increase: 2.1 (1.2-3.5)]. Cases with CA-MRSA increased approximately eight-fold during the six-year-study period. The rates of CA-MRSA in SSTIs among children increased significantly compared to CA-MSSA. The clinical impact of this increase should be evaluated, especially in patients with SSTI who are unresponsive to empirical treatment.

Assessment of infections rate due to community-acquired Methicillin-resistant Staphylococcus aureus and evaluation of risk factors in the paediatric population.

We aimed at assessing the frequency of Community-acquired Methicillin-resistant Staphylococcus aureus (CA-MRSA) infections, identifying its risk factors and evaluating resistance patterns of Staphylococcus aureus to various antibiotics in order to recommend the optimal empirical treatment for suspected Staphylococcus aureus infections. We reviewed the medical records of children who were treated at Shaare Zedek medical centre, located in Jerusalem, Israel, over the years 2008-2019 and had a positive culture for Staphylococcus aureus. Patients with CA-MRSA infections were compared with Methicillin-susceptible Staphylococcus aureus (CA-MSSA) infections. In this study, 620 paediatric patients were included. The number of children in the CA-MRSA study group was 124, while the MSSA control group consisted of 496 children. Risk factors for CA-MRSA infections included young age (1-5years), female sex, Arab ethnicity and residence in East Jerusalem. The incidence of CA-MRSA increased over the past decade, with an average of 11.2%. An increase in MSSA resistance to clindamycin was noted while Trimethoprim-Sulphamethoxazole resistance remained low. The incidence of CA-MRSA in Jerusalem was rising, along with changes in resistance patterns of both MSSA and MRSA to various antibiotic agents. In order to optimise empirical treatment for suspected staphylococcal infection, continued monitoring of CA-MRSA prevalence and resistance rates is essential.

Methicillin-resistant Staphylococcus aureus nasal carriage among janitors working in hospital and non-hospital areas: a comparative cross-sectional study

BackgroundNasal colonization of Methicillin-resistant Staphylococcus aureus (MRSA) plays a key role in the epidemiology and pathogenesis of both healthcare-associated and community-acquired MRSA infections in various populations. Screening of MRSA nasal colonization is important in the prevention and control of infection and may provide useful information to guide antimicrobial therapy. This study aimed to determine nasal carriage of MRSA, its antimicrobial susceptibility pattern, and associated factors among janitors working in hospital & non-hospital areas at the University of Gondar, Northwest Ethiopia.MethodsA comparative cross-sectional study was carried out in a total of 436 study participants (221 hospital and 215 non-hospital janitors) from January to May 2019. The study participants were sampled using a simple random sampling technique. Data on socio-demographic characteristics and associated factors were collected through face to face interviews using a structured questionnaire. Nasal swabs were collected and inoculated into Mannitol salt agar. MRSA was detected using cefoxitin (30 µg) disc and an antibiotic susceptibility test was done using the disc diffusion method. Data were entered and analyzed using SPSS version 20 statistical package. P value ≤ 0.05 was considered as statistically significant.ResultsThe overall prevalence of S. aureus was 101/436 [23.2%, (95% CI: 19.3–27.8)], of which, 29.4% (65/221) were isolated from hospital and 16.7% (36/215) non-hospital janitors. The prevalence of MRSA was 4.8% (21/436) [95% CI: 3.0–6.9]; of these, 8.1% (18/221) of the isolates were from the hospital and 1.4% (3/215) non-hospital janitors, while methicillin-sensitive S. aureus (MSSA) in hospital & non-hospital janitors were 49 (22.2%) and 31 (14.4%), respectively. Among the MRSA isolates, 52.4% (11/21) were multi-drug resistant. Of these, 42.9% (9/18) were isolated from hospital and 66.7% (2/3) non-hospital janitors. Hence, nasal carriage of MRSA was significantly associated with hospitalization within the preceding year (AOR = 3.15, CI = 1.13–8.71).ConclusionThe present study revealed that high MSSA and MRSA were isolated from the hospital as compared to non-hospital janitors and high rates of antibiotics resistance were recorded in the hospital janitors. Consequently, hospitalizations were significantly associated with MRSA. Accordingly, regular screening of carriers in apparently healthy janitors is required for the prevention of nosocomial infections.

Observational study of skin and soft-tissue Staphylococcus aureus infection in patients infected with HIV-1 and epidemics of Panton–Valentine leucocidin-positive community-acquired MRSA infection in Osaka, Japan

BackgroundIn patients infected with human immunodeficiency virus (HIV)-1 at our hospital, we observed increases in skin and soft-tissue infections (SSTIs) by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Therefore, we analyzed factors related to CA-MRSA infection and performed a molecular epidemiological investigation. MethodsHIV-1-infected patients were diagnosed with SSTIs related to S. aureus between 2007 and 2017, and MRSA was classified into community and hospital-acquired types according to published criteria. Information was collected retrospectively from clinical records, and multivariate analysis by logistic regression was performed concerning factors related to CA-MRSA infection. We evaluated the staphylococcal cassette chromosome mec (SCCmec) type, multilocus sequence type, and the presence of genes encoding Panton–Valentine leucocidin (PVL) in 27 MRSA samples isolated during and after 2015. ResultsWe found 218 episodes of SSTIs in 169 patients, and among initial episodes of SSTIs, the MRSA ratio was higher from 2015 to 2017 relative to that from 2007 to 2014 (88% vs. 44%; p < 0.0001). Multivariate analysis showed that in men having sex with men [MSM; odds ratio (OR): 13] and exhibiting onset during and after 2015 (OR: 5.4), CD4+ cell count ≥200 cells/μL (OR: 5.6) and the presence of lesions in the lower abdomen or buttocks (OR: 9.5) were independent factors related to CA-MRSA infection. Additionally, PVL+/ST8/SCCmec type IV MRSA was the predominant pathogen (22 cases; 81%). ConclusionsThese data describe an increased prevalence of SSTIs due to PVL-positive ST8-MRSA-IV, not previously considered epidemic in Japan, in MSM infected with HIV-1 in Osaka, Japan.

Prevalence and association of Panton-Valentine Leukocidin gene with the risk of sepsis in patients infected with Methicillin Resistant Staphylococcus aureus

BackgroundPanton-Valentine Leukocidin (PVL), is one of the virulence gene expressed by Methicillin Resistant Staphylococcus aureus (MRSA) and is known to be associated with severe form of community acquired MRSA infection. The aim of this study is to investigate its prevalence in our setting and patient’s clinical outcome. MethodsA cross sectional study involve retrospective record review were done involving 90 MRSA positive isolates between November 2016 and October 2017. Multiplex PCR was performed to detect femA, mecA and PVL genes. Clinical presentation and outcomes of patients were reviewed and presented as descriptive analysis. ResultsAll of the 90 MRSA isolates included in this study were positive for femA and mecA genes following PCR. PVL gene was detected in 20% (n = 18) of the isolates of which 61.1% (n = 11) were community acquired infections and 38.8% (n = 7) were hospital acquired. Case distribution from community acquired infections include patients with skin and soft tissue infections (33.3%, n = 6), infected diabetic foot ulcers (16.7%, n = 3), and one patient each (5.5%, n = 1) for community acquired pneumonia and meningitis. Half of the PVL positive MRSA cases (50%, n = 9) were having sepsis and four of them succumbed to death due to severe infection. ConclusionThis study shows a high prevalence of PVL positive MRSA infection in our population. Skin and soft tissue infections accounting for the major sources. In addition, the presence of the PVL gene is associated with increased risk for developing sepsis.

Community-Acquired Methicillin-Resistant Staphylococcus aureus Infections in Acutely Ill Children: A Retrospective Case-Control Study.

To test if admission clinical and laboratory variables could reliably discriminate community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections from methicillin-sensitive Staphylococcus aureus (MSSA) infections in acutely ill children, and to describe the epidemiology, clinical features and outcomes among children with Staphylococcal infections admitted to the hospital. The authors conducted this retrospective case-control study comparing children with CA-MRSA and MSSA infections admitted to hospital between June 2014 and June 2017. They describe the evolving epidemiology and attempt to identify clinical and laboratory variables that can differentiate MRSA cases from MSSA controls. They used multivariate logistic regression to identify independent predictors of MRSA infection and Cox-proportional hazard analysis to compare survival times. Seventy-three children were enrolled, of which 35 had CA-MRSA and 38 had MSSA infections. Children in MRSA group were younger [median (IQR) age in months: 36 (12, 62) vs. 56 (37, 96); p = 0.032]. MRSA and MSSA groups had similar rate of skin and soft tissue involvement (SSTI) [62.9% vs. 54.1%; p = 0.449]. Median duration of illness was lower in MRSA, 6 vs. 8.5 d (p = 0.001). TLC of 8100 or less was 82% sensitive and 94% specific for MRSA sepsis at admission [AUROC = 0.64 (0.51-0.77), p = 0.04]. Mortality (8.6% vs. 10.5% p = 1.0) and length of ICU stay (7.2 vs. 9.3 d, p = 0.24) were similar in both. None of the admission variables were predictive of MRSA culture-positivity on regression analysis. The hospital-based incidence of CA-MRSA infections among children appears to be increasing. None of the admission clinical or laboratory variables could reliably identify CA-MRSA infections. As there seems to be no reliable way to differentiate children with MSSA and MRSA infections, physicians may consider empiric initiation of broad-spectrum antibiotics at admission to cover both MSSA and MRSA, especially in critically ill children with suspected Staphylococcal infections.

A risk as an infection route: Nasal colonization of methicillin-resistant Staphylococcus aureus USA300 clone among contact sport athletes in Japan

Panton-Valentine leukocidin (PVL)-positive USA300 clone is a highly pathogenic and global epidemic community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clone. Athletes are particularly vulnerable to CA-MRSA infection because of the frequency of skin trauma, close-contact situations, and sharing of equipment that is customary in the athletic setting. We experienced a case of Japanese collegiate football player with septic pulmonary emboli secondary to infectious iliofemoral deep venous thrombosis caused by the USA300 clone. Here, we screened the nasal carriage of USA300 clone colonization among asymptomatic teammate of the patient to elucidate the infection route. Among 69 nasal samples, CA-MRSA strains were found in 5.8% (four samples). Molecular epidemiological analyses showed that three of the CA-MRSA strains were USA300 clone. Furthermore, pulsed-field gel electrophoresis revealed that all nasal USA300 clones showed 100% identity with the USA300 clone isolated from their teammate with critical infection. Our findings indicate that nasal colonization of the PVL-positive CA-MRSA, especially USA300 clone, pose a threat among contact sport athletes in Japan likewise other countries. An immediate infection control strategy for contact sport athletes is necessary to prevent outbreaks of PVL-positive CA-MRSA infections.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) clones from Paraguayan children.

Staphylococcus aureus is considered one of the most important human pathogens, and its levels of resistance to methicillin have increased even in strains isolated from people without nosocomial risk factors. Molecular analysis is essential for understanding the patterns of dissemination. The objective of this study was to identify community-acquired methicillin-resistant S. aureus (CA-MRSA) clones that infected Paraguayan children patients in two periods of time. An observational, descriptive study was designed to determine the genetic variability of 115 isolates of CA-MRSA recovered from children who attended four reference centers in Paraguay between 2009-2010 and 2012-2013. The combined use of Pulsed Field Gel Electrophoresis (PFGE), Multi-Locus Sequencing Typing, Multi-Locus Variable Analysis (MLVA) and Spa typing techniques allowed the identification of two dominant clones: ST30-IV-t019 (77%) and ST5-IV-t311 (10%), and the establishment of the former as the leading cause of CA-MRSA infections in children during the study period. This is the first study that provides epidemiological information as well as microbiological and molecular characteristics of CA-MRSA isolates recovered from children from Asunción and the Central Department of Paraguay.

Antibiotic use among twelve Canadian First Nations communities: a retrospective chart review of skin and soft tissue infections

BackgroundPrevious publications indicated an emerging issue with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), particularly skin and soft tissue infections (SSTIs), in Indigenous communities in Canada. The objectives of this analysis were to explore the prevalence of SSTIs due to CA-MRSA and patterns of antimicrobial use in the community setting.MethodsA retrospective chart review was conducted as part of an environmental scan to assess antibiotic prescriptions in 12 First Nations communities across five provinces in Canada including Alberta, Saskatchewan, Manitoba, Ontario, and Québec. Charts were randomly selected from nursing stations and patients who had accessed care in the previous 12 months and were ≥ 18 years were included in the review. Data was collected from September to December, 2013 on antibiotic prescriptions, including SSTIs, clinical symptoms, diagnostic information including presence of CA-MRSA infection, and treatment.ResultsA total of 372 charts were reviewed, 60 from Alberta, 70 from Saskatchewan, 120 from Manitoba, 100 from Ontario, and 22 from Québec. Among 372 patients, 224 (60.2%) patients had at least one antibiotic prescription in the previous 12 months and 569 prescriptions were written in total. The prevalence of SSTIs was estimated at 36.8% (137 cases of SSTIs in 372 charts reviewed). In 137 cases of SSTIs, 34 (24.8%) were purulent infections, and 55 (40.2%) were due to CA-MRSA.ConclusionsThis study has identified a high prevalence of antibiotic use and SSTIs due to CA-MRSA in remote and isolated Indigenous communities across Canada. This population is currently hard to reach and under-represented in standard surveillance system and randomized retrospective chart reviews can offer complimentary methodology for monitoring disease burden, treatment and prevention.

1523. Clinical Epidemiology of Children with Orbital Cellulitis

BackgroundThe microbiology of pathogens causing orbital cellulitis in children is evolving over time, with studies from around 10 years ago describing MRSA as responsible for anywhere from 0 to 13% of cases of orbital cellulitis. However, the prevalence of community-acquired MRSA infections has declined over the past decade. A current understanding of the bacteria most commonly found to be responsible for orbital cellulitis would be important to inform the empiric antibiotic regimens for cases of orbital cellulitis in which no microbiologic data are available.MethodsThis is a single-center retrospective cohort study of children ≤18 years hospitalized with orbital cellulitis at Children’s National Medical Center between January 1, 2017 and July 31, 2018. We excluded children with immunocompromising conditions, cystic fibrosis, underlying craniofacial abnormality, or recent craniofacial or otolaryngologic surgery. Baseline clinical characteristics, microbiologic data, clinical outcomes, and antibiotic treatment data were abstracted through structured chart review and summarized with descriptive statistics.ResultsWe identified 68 children that met inclusion criteria, with an average age of 8.2 years; 66.2% were male, 48.5% were African American, and 14.7% were Hispanic. Most (67.6%) had no underlying medical problems, 14.7% had asthma, and 22.1% had allergic rhinitis. The median duration of symptoms prior to presentation was 4 days. An abscess or phlegmon was identified in 41 of the 68 (60.3%). Three patients (4.4%) developed intracranial complications. About one-quarter (27.9%) of all patients in the cohort underwent surgical drainage. The most commonly identified pathogens were viridans group streptococci (7/19, 36.8%), followed by Staphylococcus aureus (4/19, 21.1%). Anti-MRSA therapy was provided empirically in almost all (95.6%) of patients.ConclusionOne-quarter of all patients hospitalized for orbital cellulitis underwent surgical drainage, and viridans group streptococci and S. aureus were the most commonly isolated pathogens. While MRSA was isolated in only one patient (5.2%), almost all received empiric anti-MRSA therapy. Disclosures All authors: No reported disclosures.

Frequency of Community-acquired Methicillin-resistant Staphylococcus aureus in Pediatric Population in a General Hospital in São Paulo, Brazil, Over 5 Years.

We retrospectively evaluated the frequency of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in children at a general hospital in São Paulo, Brazil, from 2011 to 2015. Of 64 patients with confirmed S. aureus infection, 11 (17.2%) had CA-MRSA. CA-MRSA infections in Brazil, and in particular those with a severe presentation, should not be overlooked.