Community-associated Methicillin-resistant Staphylococcus Aureus Colonization Research Articles

Increasing of New CA-MRSA Infections Detected in people living with HIV Who Engage in Chemsex in Barcelona: An Ambispective Study.

There are no data on community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in the context of the chemsex phenomenon. This study aimed to characterize CA-MRSA-related infections in a cohort of people living with HIV (PLWH) who engage in chemsex. At the Hospital Clinic of Barcelona, from February 2018 to January 2022, we analyzed CA-MRSA infections diagnosed in a cohort of PLWH who engage in chemsex. Epidemiological, behavioral and clinical variables were assessed. Mass spectrometry identification and antimicrobial susceptibility testing were performed on MRSA isolates. Pulse field electrophoresis was used to assess the clonality of the MRSA strains. The presence of Panton-Valentine leukocidin was also investigated. Among the cohort of 299 participants who engage in chemsex, 25 (8%) with CA-MRSA infections were identified, 9 at baseline and 16 with incident cases; the cumulative incidence was 5.5% (95% CI: 3.2%, 8.8%). The most common drugs were methamphetamine (96%) and GHB/GBL (92%). Poly-consumption and slamming were reported by 32% and 46%, respectively. CA-MRSA was isolated from the infection sites of 20 participants, and CA-MRSA colonization was confirmed in the remaining 5 persons. Seventy-one percent had used antibiotics in the previous year. All participants presented with skin and soft tissue infections, 28% required hospitalization, and 48% had recurrence. Of the 23 MRSA isolates further studied, 19 (82,6%) belonged to the same clone. Panton-Valentine leukocidin was detected in all isolates. PLWH who engage in chemsex may present with CA-MRSA infections. Clinical suspicion and microbiological diagnosis are required to provide adequate therapy, and CA-MRSA prevention interventions should be designed.

Staphylococcus aureus and CA-MRSA Carriage among Brazilian Indians Living in Peri-Urban Areas and Remote Communities.

The emergence of Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections among indigenous populations has been reported. Usually, indigenous communities live in extreme poverty and are at risk of acquiring infections. In Brazil, healthcare inequality is observed in this population. To date, there are no reports of CA-MRSA infections, and no active search for asymptomatic S. aureus carriage has been conducted among Brazilian Indians. The aim of this study was to investigate the prevalence of colonization with S. aureus and CA-MRSA among Brazilian Indians. We screened 400 Indians (from near urban areas and remote hamlets) for S. aureus and CA-MRSA colonization. The isolates were submitted to clonal profiling by pulsed-field gel electrophoresis (PFGE), and selected isolates were submitted to multilocus sequence typing (MLST). Among 931 specimens (nasal and oral) from different indigenous individuals in remote hamlets, S. aureus was cultured in 190 (47.6%). Furthermore, CA-MRSA was found in three isolates (0.7%), all SCCmec type IV. PFGE analysis identified 21 clusters among the S. aureus isolates, and MLST analysis showed a predominance of sequence type 5 among these isolates. Our study revealed a higher prevalence of S. aureus carriage among Shanenawa ethnicity individuals (41.1%). Therefore, ethnicity appears to be associated with the prevalence of S. aureus in these populations.

Prevalence of methicillin-resistant Staphylococcus aureus colonization in HIV-infected patients in Barcelona, Spain: a cross-sectional study

BackgroundColonization by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been found to be markedly more common in HIV-infected individuals in the USA. Studies evaluating the prevalence MRSA colonization in HIV-infected populations in Europe are scarce. The aim of this study was to investigate the prevalence of MRSA colonization in a cohort of HIV-infected patients in Barcelona, Spain.MethodsNasal and pharyngeal S. aureus carriage was assessed in a random sample of 190 patients from an outpatient HIV clinic. Nasal and pharyngeal swab specimens were obtained for staphylococcal culture from 190 and 110 patients respectively. All MRSA isolates were screened for Panton-Valentine leukocidin (PVL) genes by PCR. Molecular characterization of MRSA isolates was performed by multilocus sequence typing. Data related to HIV infection, healthcare exposure, and previously described risk factors for MRSA were collected from medical records and a questionnaire administered to each patient.ResultsThe patients’ characteristics were as follows: male, 83 %; median (IQR) age, 45 (39–49) years; intravenous drug users, 39 %; men who have sex with men, 32 %; heterosexual, 26 %; CD4 count, 528/μL (IQR 351–740); on antiretroviral therapy, 96 %; and undetectable plasma viral load, 80 %. Sixty-five patients (34 %) were colonized by S. aureus. MRSA colonization was found in 1 % and 2 % of nasal and pharyngeal samples respectively. No PVL positive MRSA strains were detected and all the MRSA isolates belonged to typical hospital-acquired clones.ConclusionsOur data suggest that CA-MRSA colonization is not currently a problem in HIV-infected individuals in our area.

Anatomic sites of colonization with community-associated methicillin-resistant Staphylococcus aureus.

Anatomic sites of colonization with community-associated methicillin-resistant Staphylococcus aureus.

Community-Associated Methicillin-Resistant Staphylococcus aureus Colonization Burden in HIV-Infected Patients

The epidemic of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has had a disproportionate impact on patients with human immunodeficiency virus (HIV). We evaluated CA-MRSA colonization burden (number of colonized sites per total number sampled) among HIV-infected and HIV-negative inpatients within 72 hours of hospitalization. From March 2011 through April 2012, we obtained cultures from nasal and extranasal sites (throat, axilla, inguinal, perirectal, and chronic wound if present) and collected risk factor data. Of 745 patients (374 HIV-infected, 371 HIV-negative), 15.7% were colonized with CA-MRSA at any site: 20% of HIV and 11% of HIV-negative patients (relative prevalence=1.8, P=.002). HIV-infected patients had a higher prevalence of nasal, extranasal, and exclusive extranasal colonization as well as higher colonization burden. Perirectal and inguinal areas were the extranasal sites most frequently colonized, and 38.5% of colonized patients had exclusive extranasal colonization. Seventy-three percent of isolates were identified as USA300. Among HIV-infected patients, male sex, younger age, and recent incarceration were positively associated whereas Hispanic ethnicity was negatively associated with higher colonization burden. Among HIV-negative patients, temporary housing (homeless, shelter, or substance abuse center) was the only factor associated with higher colonization burden. Predictors of USA300 included HIV, younger age, illicit drug use, and male sex; all but 1 colonized individual with current or recent incarceration carried USA300. HIV-infected patients were more likely to have a higher CA-MRSA colonization burden and carry USA300. In certain populations, enhanced community and outpatient-based infection control strategies may be needed to prevent CA-MRSA cross-transmission and infection.

Lessons from a Community-Based Infection Prevention Study

From Rush University Medical Center and Stroger Hospital of Cook County, Chicago, Illinois. Received July 20, 2010; accepted July 21, 2010; electronically published October 18, 2010. Infect Control Hosp Epidemiol 2010; 31(12):1216-1218 2010 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2010/3112-0002$15.00. DOI: 10.1086/657137 Chlorhexidine gluconate (CHG) is an antiseptic agent that has been used for multiple purposes including catheter insertion preparation and maintenance, body antisepsis, and application in the nasopharynx and oropharynx. Antisepsis with this agent is believed to reduce colonization with potential pathogens, which in turn would lead theoretically to a reduction in the number of infections. Bathing medical intensive care unit patients with CHG cloths has been effective in reducing the rate of central venous catheter–associated bloodstream infections and the rate of colonization with vancomycin-resistant Enterococcus. CHG bathing, often in combination with nasal application of mupirocin and oral antimicrobial agents, also has been found to decrease rates of colonization with and possibly rates of acquisition of methicillin-resistant Staphylococcus aureus (MRSA). Although it is a promising infection control intervention, examination of the efficacy of CHG bathing outside of the hospital has been limited. MRSA was once considered to be solely a nosocomial pathogen. However, the epidemiology of MRSA has changed—it has emerged in community settings among individuals without prior healthcare exposures, so-called community-associated MRSA (CA-MRSA). Although CA-MRSA can cause invasive disease, such as bloodstream infection, it predominantly causes skin and soft-tissue infection (SSTI). Several distinct groups—military recruits, prisoners, and amateur and professional athletes—have been identified as being at increased risk for CA-MRSA colonization and infection, possibly because of crowding or close contact with other individuals. Military recruits are a unique community population for studying an infection control intervention, given their crowded living conditions, decreased access to bathing, and increased opportunity for cuts and abrasions. CA-MRSA colonization rates have been found to be higher among military recruits than among the general population, with outbreaks of CA-MRSA SSTIs among military recruits reported. Therefore, enhanced prevention efforts in a population such as this may be needed. Standard infection control recommendations for MRSA infection prevention in the community include hand hygiene, covering of wounds, not sharing personal items, and proper environmental cleaning. Decolonization regimens with agents such as CHG have been suggested as an option for individuals with recurrent MRSA infections or if MRSA transmission is occurring despite standard infection control measures; data on the efficacy of this approach, however, are limited. In this issue of the journal, the study by Whitman et al— a cluster-randomized study of military recruits attending Officer Candidate School in Quantico, Virginia—seeks to examine the effectiveness of bathing thrice weekly with CHG cloths (Sage) in this population. They found that there were no significant differences in development of SSTIs in the CHG group versus the control group (Comfort Bath), although the incidence of colonization in the nares and axilla with methicillin-susceptible S. aureus and MRSA was lower in the CHG group. However, colonization in both groups increased during the study, demonstrating the at-risk environment that a military training camp may create and underscoring the importance of infection control in this setting. Most studies examining patient bathing with CHG have occurred in hospital settings with cleansing occurring daily. Daily patient bathing with CHG has been shown to be effective at reducing colonization of skin with potential pathogens; theoretically, the reduction in pathogen burden on patient skin should lead to a decrease in the rate of SSTIs. Although studies have typically assessed daily bathing with CHG, the study by Whitman et al used self-applied thriceweekly bathing because of feasibility issues and data supporting CHG activity for as long as 24 hours. The assessment of CHG cleansing among military recruits in this study, however, was limited by the thrice-weekly bathing in conjunction with relatively poor self-reported adherence with CHG cloths (49.4% of individuals in the CHG group reported use of at least 50% of wipes by week 6). Although the authors found that there were no differences

Community-associated Staphylococcus aureus infections: pneumonia

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging health problem with distinct epidemiology. CA-MRSA colonization and infection is associated with risk factors different from healthcare-associated methicillin-resistant S. aureus infection. CA-MRSA strains pre­sent different characteristics to healthcare associated strains in terms of microbiology as well. Moreover, infection as a result of CA-MRSA may be associated with severe infections, in particular necrotizing pneumonia. CA-MRSA strains may produce Panton-Valentine leukocidin, a protein that available data suggest to be associated with the severity of the infection. Although the incidence of CA-MRSA pneumonia is relatively low, it affects mostly young, immunocompetent individuals, and in this respect constitutes a serious and potentially lethal form of community-acquired pneumonia. Current treatment suggested by international consensus guidelines includes linezolid or vancomycin often combined with clindamycin and/or rifampicin. However, clinical studies are required to clarify further therapeutic issues on timing, dosing, and choice of optimum treatment, and whether new therapeutic strategies such as vaccination and immunoglobulins could be useful. In the present review we discuss the microbiology, epidemiology, pathogenesis, and clinical aspects of community-acquired pneumonia as a result of CA-MRSA in respect of management and prevention.

Carriage of Community-Associated Methicillin-Resistant Staphylococcus aureus in a Cohort of Infants in Southern Israel: Risk Factors and Molecular Features

There are few data about the epidemiology of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) among children in Israel. This study was intended to identify risk factors for CA-MRSA colonization in healthy infants, to characterize the molecular features of colonizing organisms, and to determine whether they are responsible for health care-associated (HA) infections. Nasal cultures and demographic details were collected from a cohort of healthy infants at 5 visits between the ages of 2 and 12 months. Clinical characteristics of pediatric MRSA bloodstream infections (2001 to 2006) and wound cultures collected over 6 months were also studied. Clonal structure was evaluated by multilocus sequence typing. Isolates were studied for the staphylococcal cassette chromosome mec (SCCmec) type and for the presence of Panton-Valentine leukocidin (PVL) genes. MRSA was cultured at least once from 45 of 659 infants (346 Jewish and 313 Bedouin infants). Forty of 45 (89%) isolates were from Bedouin infants. Twenty-nine of 45 (64.4%) belonged to a new clonal complex, designated CC913, that carries SCCmec IV but not the PVL genes. CC913 was also isolated from 9/14 blood cultures and 7/8 wounds. All CC913 infections occurred in Bedouin children, and all but two were HA. In conclusion, Bedouin origin was the main risk factor for carriage of CA-MRSA. CC913 was dominant both in healthy carriers and as a cause of pediatric HA-MRSA bloodstream infections.

Prevalence of community-associated methicillin-resistantStaphylococcus aureuscolonization outside the healthcare environment

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are increasingly recognized in persons without established risk factors. Population-based prevalence studies of CA-MRSA colonization in persons without risk factors are relatively limited. Subjects aged 2-65 years were enrolled from a student recreation centre, public office building, and out-patient clinics. Persons or close contacts with a history of hospitalization, nursing-home residence, surgery, emergency-department visit, or healthcare employment during the previous year and persons with chronic debilitating illness, indwelling catheter, or surgical device were excluded. Swabs of anterior nares were obtained. Demographic and clinical information was collected. During January-June 2005, three (1.2%) of 259 subjects were colonized with MRSA. All three subjects were adults enrolled at the recreation centre. Healthy persons living in households without recent exposure to healthcare environments were at low risk for MRSA colonization. Studies from other geographic locations are needed to elucidate differences in prevalence of CA-MRSA.

Prevalence of community-associated methicillin-resistant Staphylococcus aureus colonization in men who have sex with men

Outbreaks of skin and soft tissue infections mediated by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) are being reported with increasing frequency among men who have sex with men (MSM). However, the potential role of asymptomatic colonization with this organism in perpetuating these infections is unclear. The purpose of this cross-sectional study was to determine the prevalence of colonization with CA-MRSA among a cohort of 500 MSM recruited from two inner city clinics in Toronto, Canada. Following the provision of informed consent, subjects completed a questionnaire capturing demographic and clinical variables, which may be associated with MRSA colonization. A nasal swab for MRSA was collected from each subject, and instructions were provided regarding the self-collection of a rectal swab. Cultured MRSA underwent pulsed-field gel electrophoresis and virulence testing for Panton-Valentine leukocidin gene expression. The prevalence of CA-MRSA colonization was 1.6% (95% CI: 0.5-2.6%).

A Case of Primary Infective Endocarditis Caused by Community-Associated Methicillin-Resistant Staphylococcus aureus in a Healthy Individual and Colonization in the Family

Primary community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) endocarditis has rarely been reported in healthy individuals without risk factors, such as skin and soft tissue infections, and intravenous drug abuse. We describe a case of infective endocarditis by CA-MRSA (ST72-PVL negative-SCCmec IVA) in previously healthy individuals with no underlying medical condition and CA-MRSA colonization in the family.

Community-Associated Methicillin-Resistant Staphylococcus aureus Colonization in the Upper Respiratory Tracts of Korean Military Recruits

Background: Several large outbreaks have demonstrated the threat of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in close-contact environments, such as occurs during training and quartering of military recruits training. In South Korea, which is a hospital or healthcare-associated MRSA prevalent area, military service is compulsory for all healthy young men. We surveyed and determined the extent of CA-MRSA colonization in the upper respiratory tracts of Korean military recruits. Methods: The Korean military recruits who were enrolled in a military training facility from November 2004 to March 2005 were eligible for this study. Sputum or nasopharyngeal swap was obtained from randomly selected subjects who displayed upper respiratory tract symptoms. Results: Of the 181 participants, 32 participants (17.7%) were colonized with S. aureus, and 12 participants (6.6%) were colonized with MRSA. Among the cases that were colonized with S. aureus, 37.5% (12/32) were colonized with MRSA. Antimicrobial susceptibility testing showed resistant patterns that were suggestive of the CA-MRSA strains for all of the MRSA isolates. Conclusion: This study of Korean military recruits found a great deal of showed MRSA colonization in them, and the antimicrobial resistant profile that was suggestive of a CA-MRSA strain. Further efforts to prevent the spread of MRSA infections and careful monitoring for CA-MRSA outbreaks are warranted, especially in a high risk group such as military recruits.

Spread of methicillin‐resistant Staphylococcus aureus USA300 in a neonatal intensive care unit

Reports of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in neonatal intensive care units (NICU) and in otherwise healthy patients without obvious risk factors have been increasing in frequency. Described herein is a cluster of cases of CA-MRSA USA300 strains in an NICU affecting infants, health-care workers and the health-care workers' families. Infants and health-care workers with infection and colonization due to MRSA between 1 January 2004 and 30 June 2005 in a tertiary care center NICU in San Antonio, TX were studied. Antimicrobial susceptibility testing and polymerase chain reaction detection of the mecA gene characterized the MRSA isolates. All MRSA cases were reviewed for clinical severity of infection and outcome. During the 18 months studied, a total of four (0.6%) of 676 infants had CA-MRSA bacteremia or colonization. One infant with necrotizing pneumonia died and three health-care workers who directly cared for the infected infants developed soft-tissue infections caused by CA-MRSA. Four family members of two health-care workers subsequently developed soft-tissue infections. All of the analyzed isolates (eight of nine) belonged to pulsed-field type USA300 and possessed Panton-Valentine leukocidin genes, which have been associated with severe skin and soft-tissue infections, and necrotizing pneumonia. It is likely that the CA-MRSA USA300 strain can be transmitted between NICU patients to health-care workers and their family members. The CA-MRSA cases reported here reinforce the virulence of CA-MRSA USA300 strains and emphasize the need to embrace infection control practices designed to protect hospitalized patients, health-care workers and their family members.

Prevalence of Nasal Colonization Among Patients With Community-Associated Methicillin-ResistantStaphylococcus aureusInfection and Their Household Contacts

To evaluate the prevalence of colonization among patients with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection and their household contacts. Prospective, observational laboratory study of nasal colonization among patients and their household members from September 15, 2004, to February 20, 2006. A 600-bed, urban, academic medical center. Fifty-one patients who presented with CA-MRSA infections and 49 household members had cultures of nasal swab specimens performed. Skin and soft-tissue infections were seen in 50 patients (98%) and 2 household members. Twenty-one (41%) of 51 patients and 10 (20%) of 49 household members were colonized with MRSA. An additional 5 patients (10%) and 12 household members (24%) were colonized with methicillin-susceptible Staphylococcus aureus. Most MRSA isolates (95%; infective and colonizing) carried the staphylococcal cassette chromosome mec type IV complex, and 67% represented a single clone, identical to USA 300. Of the colonized household members, 5 had isolates related to the patients' infective isolate. The frequency of CA-MRSA colonization among household members of patients with CA-MRSA infections is higher than rates reported among the general population. Among colonized household members, only half of the MRSA strains were related to the patients' infective isolate. Within the same household, multiple strains of CA-MRSA may be present.

An outbreak of methicillin-resistant Staphylococcus aureus skin infections resulting from horse to human transmission in a veterinary hospital

There are increasing reports of methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization in horses and evidence that MRSA can be transmitted between horses and humans. The objective of this study was to investigate reports of skin infection in personnel working with a foal with community-associated MRSA colonization and subsequent infection. Clinical diagnostic specimens were collected from individuals reporting skin lesions following contact with the affected foal. Nasal and groin screening swabs were collected from other veterinary personnel that attended a voluntary screening clinic. MRSA skin infections were identified in three neonatal intensive care unit personnel. Nasal colonization was subsequently identified in 10/103 (9.7%) other veterinary hospital personnel. Isolates were indistinguishable by pulsed field gel electrophoresis, classified as Canadian epidemic MRSA-5, possessed SCC mecIV, were negative for the Panton-Valentine leukocidin and were multidrug resistant. Transmission to veterinary personnel despite short-term contact with standard protective barriers highlights the potential importance of MRSA as an emerging zoonotic pathogen, and indicates that further evaluation of interspecies transmission of MRSA and means to prevent zoonotic infection are required.

Risk Factors for Colonization with Methicillin‐ResistantStaphylococcus aureus(MRSA) in Patients Admitted to an Urban Hospital: Emergence of Community‐Associated MRSA Nasal Carriage

Surveillance cultures performed at hospital admission have been recommended to identify patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) but require substantial resources. We determined the prevalence of and risk factors for MRSA colonization at the time of hospital admission among patients cared for at a public urban hospital. Anterior nares cultures were obtained within 48 h after admission during a 1-month period. A case-control study and molecular typing studies were performed. A total of 53 (7.3%) of 726 patients had a nares culture positive for MRSA, and 119 (16.4%) had a nares culture that was positive for methicillin-susceptible S. aureus. In multivariate analysis, risk factors for MRSA colonization included antibiotic use within 3 months before admission (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.2-5.0), hospitalization during the past 12 months (OR, 4.0; 95% CI, 2.0-8.2), diagnosis of skin or soft-tissue infection at admission (OR, 3.4; 95% CI, 1.5-7.9), and HIV infection. A total of 47 (89%) of 53 case patients colonized with MRSA had at least 1 of these independent risk factors, in contrast to 343 (51%) of 673 control patients (OR, 7.5; 95% CI, 3.2 -17.9). Molecular typing demonstrated that 16 (30%) of 53 MRSA nares isolates (2.2% of the 726 isolates) belonged to the USA300 community-associated MRSA (CA-MRSA) genotype. The prevalence of MRSA colonization at the time of patient admission was high (>7%). Limiting surveillance cultures to patients with >or=1 of the identified risk factors may allow for targeted screening. The emergence of CA-MRSA colonization represents a new, unrecognized reservoir of MRSA within hospitals, potentially increasing the risk for horizontal transmission.