Increased prevalence of methicillin-resistant Staphylococcus aureus nasal colonization in household contacts of children with community acquired disease

<p>Abstract</p> <p>Background</p> <p>To measure Methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) nasal colonization prevalence in household contacts of children with current community associated (CA)-MRSA infections (study group) in comparison with a group of household contacts of children without suspected <it>Staphylococcus aureus </it>infection (a control group).</p> <p>Methods</p> <p>This is a cross sectional study. Cultures of the anterior nares were taken. Relatedness of isolated strains was tested using pulse field gel electrophoresis (PFGE).</p> <p>Results</p> <p>The prevalence of MRSA colonization in the study group was significantly higher than in the control group (18/77 (23%) vs 3/77 (3.9%); p ≤ 0.001). The prevalence of SA colonization was 28/77 (36%) in the study group and 16/77 (21%) in the control group (p = 0.032). The prevalence of SA nasal colonization among patients was 6/24 (25%); one with methicillin-susceptible <it>S. aureus </it>(MSSA) and 5 with MRSA. In the study (patient) group, 14/24 (58%) families had at least one household member who was colonized with MRSA compared to 2/29 (6.9%) in the control group (p = 0.001). Of 69 total isolates tested by PFGE, 40 (58%) were related to USA300. Panton-Valetine leukocidin (PVL) genes were detected in 30/52 (58%) tested isolates. Among the families with ≥1 contact colonized with MRSA, similar PFGE profiles were found between the index patient and a contact in 10/14 families.</p> <p>Conclusions</p> <p>Prevalence of asymptomatic nasal carriage of MRSA is higher among household contacts of patients with CA-MRSA disease than control group. Decolonizing such carriers may help prevent recurrent CA-MRSA infections.</p

Prevalence and characterization of methicillin-resistant Staphylococcus aureus among healthy children in a city of Argentina

Community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a major global problem. Healthy carriers of S. aureus strains have an important role in the dissemination of this bacterium. The aim of this study was to estimate the prevalence of S. aureus and methicillin-resistant S. aureus (MRSA) carriage among healthy children in a city of Buenos Aires province, Argentina, and to determine the potential risk factors for its acquisition. We also described the molecular features of MRSA strains circulating in this population. S. aureus carriage was investigated in all children attending the last year of kindergarten during the 2008 school- year period. Household contacts of MRSA carriers were also screened. Of 316 healthy children, 98 (31.0%) carried S. aureus, including 14 MRSA carriers (4.4%) and 84 methicillin susceptible S. aureus (MSSA) carriers (26.6%). All MRSA isolates carried the SCCmec type IV cassette. Eight of the fourteen isolates were closely related to the clone responsible for most severe community- acquired MRSA infections caused in our country (CAA: PFGE A, SCCmec IV, spa t311, ST5). Two subtypes (A1 and A2) were distinguished in this group by PFGE. Both had agr type II and presented the same virulence determinants, except for PVL coding genes and sea that were only harbored by subtype A1. Our results, based on the analysis of MRSA isolates recovered in the screening of healthy children, provide evidence of a community reservoir of the major CA-MRSA clone described in Argentina.Fil: Gardella, N.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Murzicato, S.. Hospital Municipal de San Antonio de Areco; ArgentinaFil: Di Gregorio, Sabrina Noelia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Cuirolo, Arabela Ximena. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Desse, J.. Hospital Paroissien; ArgentinaFil: Crudo, F.. Hospital Municipal de San Antonio de Areco; ArgentinaFil: Gutkind, Gabriel Osvaldo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Mollerach, Marta Eugenia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

The epidemiology and transmission of methicillin-resistant Staphylococcus aureus in the community in Singapore: study protocol for a longitudinal household study.

BACKGROUND/AIM: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common multidrug-resistant organisms in healthcare settings worldwide, but little is known about MRSA transmission outside of acute healthcare settings especially in Asia. We describe the methods for a prospective longitudinal study of MRSA prevalence and transmission. METHODS: MRSA-colonized individuals were identified from MRSA admission screening at two tertiary hospitals and recruited together with their household contacts. Participants submitted self-collected nasal, axilla and groin (NAG) swabs by mail for MRSA culture at baseline and monthly thereafter for 6 months. A comparison group of households of MRSA-negative patients provided swab samples at one time point. In a validation sub-study, separate swabs from each site were collected from randomly selected individuals, to compare MRSA detection rates between swab sites, and between samples collected by participants versus those collected by trained research staff. Information on each participant's demographic information, medical status and medical history, past healthcare facilities usage and contacts, and personal interactions with others were collected using a self-administered questionnaire. DISCUSSION/CONCLUSION: Understanding the dynamics of MRSA persistence and transmission in the community is crucial to devising and evaluating successful MRSA control strategies. Close contact with MRSA colonized patients may to be important for MRSA persistence in the community; evidence from this study on the extent of community MRSA could inform the development of household- or community-based interventions to reduce MRSA colonization of close contacts and subsequent re-introduction of MRSA into healthcare settings. Analysis of longitudinal data using whole-genome sequencing will yield further information regarding MRSA transmission within households, with significant implications for MRSA infection control outside acute hospital settings

Studies of community-associated meticillin resistant Staphylococcus aureus (caMRSA) carriage in people and animals

Meticillin resistant Staphylococcus aureus (MRSA) is a leading cause of bloodstream infections in Australia and is one of the top ten pathogens with an adverse impact on human health worldwide. Infections caused by this organism were originally associated with the healthcare setting, termed healthcare-associated MRSA (haMRSA). New strains of MRSA termed community-associated caMRSA (caMRSA), with different genetic characteristics to haMRSA strains, were first identified in patients residing in remote communities in Western Australia during the early 1990’s. Colonisation with caMRSA precedes and increases the risk of subsequent infection with this organism. Research on caMRSA carriage in community settings has mainly come from Europe and the US. Community specific data for caMRSA carriage in Australia is sparse. This study aimed to detail the prevalence of MRSA in community members (n=283), as well as in groups at risk for the acquisition of MRSA, comprising contact sports participants (n=199), dogs (n=108), dog handlers (n=94), horses (n=310), horse handlers (n=38), veterinary nurses (n=48) and veterinarians (n=60). The role of household contacts and the environment as sources of caMRSA was investigated in the veterinary cohort. Genotypic analyses were used to differentiate strains of caMRSA from haMRSA, and unique strain characteristics were detailed. Genotypic tests included multiplex real-time PCR (RT-PCR), macro-restriction pulsed field gel electrophoresis (PFGE), SCCmec typing, multilocus sequence typing (MLST) and DNA microarrays. The findings of the present study revealed caMRSA poses a greater risk to veterinarians (20%), veterinary nurses (6.25%) and horse handlers (5.26%) than to all other cohorts investigated in which prevalence of caMRSA was found to be low (<2%) or absent

A literature review on community-acquired methicillin-resistant Staphylococcus aureus in the United States: Clinical information for primary care nurse practitioners

Purpose: To analyze the state of the science of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in the United States to support the integration of current knowledge for primary care nurse practitioners’ (PCNP) practice. Data sources: Published research limited to U.S. studies in MEDLINE, CINAHL, and Cochrane Review from 1950 to the week of September 4, 2008. Investigations were identified through electronic search engines and databases. Manual searches were done of hard copy references in journal articles. Citations and reference lists for English language research studies of CA-MRSA in the United States were reviewed to identify additional research that fit evaluation criteria for this analysis. Conclusions: Until the late 1990s, healthcare-associated MRSA (HA-MRSA) was the predominant cause of serious infections. Recently, CA-MRSA has caused infections in previously healthy nonhospitalized people. Major demographic and epidemiological differences exist between the two types of resistant bacteria; the emergence of CA-MRSA suggests new implications for primary care. Implications for practice: PCNPs will undoubtedly treat MRSA infections and need a comprehensive understanding of the pathogenicity, diagnosis, and management of CA-MRSA to ensure expedient and appropriate treatment. This will help to prevent invasive disease as a result of improperly treated infections.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79099/1/j.1745-7599.2010.00571.x.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/79099/2/JAAN_571_sm_Tables1.pd

Infect Control Hosp Epidemiol

OBJECTIVE.To identify risk factors for recurrent methicillin-resistant Staphylococcus aureus (MRSA) colonization.DESIGN.Prospective cohort study conducted from January 1, 2010, through December 31, 2012.SETTING.Five adult and pediatric academic medical centers.PARTICIPANTS.Subjects (ie, index cases) who presented with acute community-onset MRSA skin and soft-tissue infection.METHODS.Index cases and all household members performed self-sampling for MRSA colonization every 2 weeks for 6 months. Clearance of colonization was defined as 2 consecutive sampling periods with negative surveillance cultures. Recurrent colonization was defined as any positive MRSA surveillance culture after clearance. Index cases with recurrent MRSA colonization were compared with those without recurrence on the basis of antibiotic exposure, household demographic characteristics, and presence of MRSA colonization in household members.RESULTS.The study cohort comprised 195 index cases; recurrent MRSA colonization occurred in 85 (43.6%). Median time to recurrence was 53 days (interquartile range, 36\u201384 days). Treatment with clindamycin was associated with lower risk of recurrence (odds ratio, 0.52; 95% CI, 0.29\u20130.93). Higher percentage of household members younger than 18 was associated with increased risk of recurrence (odds ratio, 1.01; 95% CI, 1.00\u20131.02). The association between MRSA colonization in household members and recurrent colonization in index cases did not reach statistical significance in primary analyses.CONCLUSION.A large proportion of patients initially presenting with MRSA skin and soft-tissue infection will have recurrent colonization after clearance. The reduced rate of recurrent colonization associated with clindamycin may indicate a unique role for this antibiotic in the treatment of such infection.K24 AI080942/AI/NIAID NIH HHSUnited States/U54CK000163/ACL/ACL HHSUnited States/U54-CK000163/CK/NCEZID CDC HHSUnited States/K24-AI080942/AI/NIAID NIH HHSUnited States

High incidence of acquiring methicillin-resistant <i>Staphylococcus aureus</i> in Brazilian children with Atopic Dermatitis and associated risk factors

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) colonization in Atopic Dermatitis (AD) patients can contribute to worsening their clinical condition. OBJECTIVE: A cohort study was carried out to determine the incidence of MRSA acquisition and its risk factors in AD children. METHODS: Patients with AD (2 months-14 years old) were followed up for about 1 year at a reference center for AD treatment in Rio de Janeiro, Brazil, from September 2011 to February 2014. Nasal swabs from patients and contacts were collected every 2 months. The SCORAD system assessed the severity of the AD. S. aureus isolates were evaluated to determine the methicillin resistance and the clonal lineages. RESULTS: Among 117 AD patients, 97 (82.9%) were already colonized with S. aureus and 26 (22.2%) had MRSA at the first evaluation. The incidence of MRSA acquisition in the cohort study was 27.47% (n = 25). The SCORAD assessments were: mild (46.15%), moderate (37.36%) or severe (16.48%). Risk factors were: colonized MRSA contacts (HR = 2.27; 95% CI: 1.16-7.54), use of cyclosporine (HR = 5.84; 95% CI: 1.70-19.98), moderate or severe AD (HR = 3.26; 95% CI: 1.13-9.37). Protective factors were: availability of running water (HR = 0.21; 95% CI: 0.049-0.96) and use of antihistamines (HR = 0.21; 95% IC: 0.64-0.75). MRSA isolates carried the SCCmec type IV and most of them were typed as USA800/ST5. CONCLUSIONS: The high incidence of MRSA acquisition found among AD patients and the risk factors associated show that an effective surveillance of MRSA colonization in these patients is needed

Persistent Staphylococcus aureus Colonization Is Not a Strongly Heritable Trait in Amish Families

About 20% of adults are persistently colonized with S. aureus in the anterior nares. Host genetic factors could contribute susceptibility to this phenotype. The objective of this study was to determine whether the phenotype of persistent S. aureus colonization aggregates in family members who live in different households. Healthy adults and their eligible same sex siblings who lived in different households were recruited from the Old Order Amish of Lancaster, Pennsylvania. All participants had two cultures of the anterior nares to determine if they were persistently colonized with S. aureus. Three hundred and ninety eight participants finished the study, of whom 166 were index cases and 232 were siblings of index cases. Eighteen per cent (71/398) of all participants and 17% (29/166) of index cases were persistently colonized with S. aureus. Twenty two per cent (8/36) of siblings of persistently colonized index cases were persistently colonized with S. aureus compared to 17% (34/196) of siblings of non-persistently colonized index cases, yielding a prevalence rate ratio of 1.28 (95% CI: 0.65–2.54, p = 0.64) and sibling relative risk of 1.25 (95% CI: 0.65–2.38, p = 0.51). The heritability of persistent colonization was 0.19±0.21 (p = 0.31). Persistent S. aureus colonization does not strongly aggregate in Amish family members in different households and heritability is low, suggesting that environmental factors or acquired host factors are more important than host genetic factors in determining persistent S. aureus colonization in this community

Transmission dynamics, pathogenicity, and immunological biomarkers of livestock-associated Staphylococcus aureus, North Carolina, USA.

Introduction. In the past decade it has become evident that animal-adapted Staphylococcus aureus (S. aureus), including methicillin-resistant S. aureus (MRSA) and multidrug-resistant S. aureus (MDRSA), have emerged among pigs raised on industrial hog operations (IHOs) and among humans who have frequent contact with, or live near IHOs both globally and in the USA. IHO workers in the USA are at an increased risk of carrying livestock-associated (LA-) S. aureus, including LA-MRSA and LA-MDRSA, and developing LA-S. aureus skin and soft tissue infections (SSTI). The population structure, transmission dynamics, relative pathogenicity, and immunological biomarkers of LA-S. aureus commonly contracted by IHO workers and their family members in the USA remains poorly understood. Objectives. 1) Elucidate the population structure and transmission dynamics of LA-S. aureus clonal complex 9 (CC9) between pigs raised on IHOs (IHO pigs) and humans in North Carolina (NC), USA, a region with a particularly high density of IHOs, 2) Determine the degree to which LA-S. aureus strains contracted by IHO workers cause disease relative to a highly pathogenic epidemic community-associated (CA-) MRSA strain (i.e. USA300 clone, SF8300) in a mouse model of SSTI, and 3) Develop antigen-specific antibody-based oral fluid (OF) biomarkers and examine their associations with S. aureus nasal carriage and SSTI outcomes among a population of IHO workers and their household contacts. Methods. In Chapter 1, 81 LA-S. aureus CC9 isolates were subject to bioinformatic analysis, including core-genome SNP-based phylogenetic analysis and genotyping for antimicrobial resistance (AMR) and virulence factor (VF) genes. In Chapter 2, measures of pathogenicity, including lesion size, innate immune host response, and colony forming units (CFUs), were compared between mice infected with either LA-S. aureus CC9 or CC398 strains to mice infected with CA-MRSA clone, SF8300. In Chapter 3, the development of an OF multiplex S. aureus Luminex enzyme immunoassay (EIA) that can be employed in occupational and community settings is outlined. Associations between S. aureus nasal carriage and SSTI outcomes and S. aureus antigen-specific antibody levels in OF were examined among IHO workers and their family members. Results. In Chapter 1, high-resolution phylogenetic and genotyping analysis of LA-S. aureus CC9 isolates revealed two distinct transmission clusters which contained IHO pig and human isolates with a high degree of phylogenetic relatedness. Transmission cluster isolates were enriched with multiple acquired AMR genes and a MDRSA phenotype. In Chapter 2, mice infected with CC398 LA-S. aureus strains developed larger lesion sizes with higher bacterial burden than mice infected with CA-MRSA (USA300 clone, SF8300). The LA-S. aureus infected mice had decreased IL-1β protein levels compared with CA-MRSA-infected mice, suggesting a suboptimal host response to LA-S. aureus SSTIs. In Chapter 3, an OF multiplex S. aureus EIA was developed. Consistent with previous findings in serum, OF IgG antibody levels against SCIN, ClfA, and AT were elevated among adults (ages 18-49) compared to children (ages 7-17). OF IgG levels waned with aging (ages 50-82), whereas IgA levels remained elevated. Anti-ClfA IgA and IgG antibody levels were significantly elevated among IHO workers who carried S. aureus, multidrug-resistant S. aureus (MDRSA), and tetracycline-resistant S. aureus (tet[R]-S. aureus) intranasally. Anti-ClfA IgA levels were positively and anti-SCIN levels negatively associated with self-reported SSTI. Conclusions. 1) LA-S. aureus CC9 in the USA is distinct from lineages in Europe and Asia, and can be transmitted between IHO pigs and humans. A MDRSA phenotype, and a significantly increased number of acquired AMR genes, is associated with pig-human transmissions. 2) LA-S. aureus CC398 and CC9 display an equivalent or greater degree of pathogenicity compared to CA-MRSA USA300, SF8300, in a mouse model of SSTI. 3) OF antibodies against ClfA may serve as non-invasive biomarkers of S. aureus colonization and SSTI among IHO workers and their household contacts