Risk Factors For Methicillin-resistant Staphylococcus Aureus Carriage Research Articles

Does universal nasal/skin decolonization in nursing homes affect risk factors for MRSA carriage?

Background: A regional decolonization intervention (SHIELD-OC) involving universal chlorhexidine for routine bathing and 5 days of twice-daily nasal iodophor every other week in nursing homes (NHs) recently demonstrated marked reductions in multidrug-resistant organisms, all-cause hospitalizations, and infection-related hospitalizations in Orange County, California. Specific to methicillin-resistant Staphylococcus aureus (MRSA), NH prevalence (nares, skin, or perirectal) decreased from 43% to 29%. Methods: We conducted a retrospective cohort study evaluating the impact of decolonization on factors associated with MRSA carriage. The cohort included residents from 18 SHIELD-OC NHs who were sampled for MRSA using nares, axilla, groin, and perirectal cultures. A point-prevalence survey was conducted in 2016–2017 (before decolonization, 50 randomly sampled residents per NH) and in 2018–2019 (decolonization, all residents sampled). Resident characteristics were obtained from their most proximal admission, quarterly, and/or discharge assessment using data mandated for NH reporting (CMS minimum data set), and included demographics, medical devices, comorbidities (including Alzheimer’s disease and related dementias or ADRD), and mobility and hygiene needs. We used generalized-linear mixed models stratified by decolonization and clustered by NH to identify differences in factors associated with MRSA carriage. Results: Of the 2,351NH residents, 2,255 (96%) had characteristics available in the CMS data set. Of the 2,255 residents included, 774 (34%) were MRSA carriers. Before decolonization, medical devices (OR, 2.5), limited mobility (OR, 1.6), and diabetes (OR, 1.4) were significantly associated with MRSA carriage in an adjusted model (Table). During decolonization, these effects were mitigated (medical device OR, 2.5–1.1; diabetes OR, 1.4–0.9) and were no longer significantly associated with MRSA carriage. Male sex appeared to have more of an effect in the decolonization phase (OR, 1.3–1.6), but limited mobility remained stable (OR, 1.6–1.7). Several variables were collinear. Presence of a medical device was collinear with postacute stays (<100 days) and Medicaid insurance. Limited mobility was associated with limited ability for hygienic self-care. ADRD was collinear with age. Final adjusted models accounted for medical devices, limited mobility, diabetes, ADRD, cancer, sex, and ethnicity. Conclusions: In a large interventional cohort of 18 NHs, factors associated with MRSA carriage changed after adoption of universal decolonization. Specifically, the increased risk of MRSA associated with medical devices and diabetes were substantially mitigated by decolonization, suggesting that these risks are modifiable. These long-term care findings are consistent with clinical trials showing reductions in MRSA carriage after implementing chlorhexidine bathing in ICUs and in non-ICU patients with devices. The ability of decolonization to attenuate the risk of MRSA carriage among diabetics or other potential high-risk groups deserves further study.Disclosures: None

Risk factors associated with methicillin-resistant Staphylococcus aureus isolation from serially collected sputum samples of patients hospitalized with pneumonia

IntroductionRisk factors associated with the new detection of methicillin-resistant Staphylococcus aureus (MRSA) during hospitalization remain unclear. This study aimed to identify risk factors associated with MRSA isolation from the sputum of patients admitted with pneumonia, during their hospitalization. MethodsPatients were prospectively enrolled from 2003 to 2012. Sputum samples were collected for bacterial cultures on days 1, 4, 7, 11, and 14 of hospitalization and thereafter. Cases of MRSA first isolated from sputum obtained before day 4 were defined as “carriage on admission.” Cases of MRSA first isolated on day 4 and thereafter, were defined as “new detection after admission.” Statistical analysis was used to investigate the risk factors associated with MRSA isolation. ResultsMRSA was isolated from 167 of 1,008 patients (carriage: 47; new detection: 120). Multivariate analysis revealed that the risk factors for MRSA carriage were activities of daily living (ADL) disability prior to admission (odds ratio [OR], 2.92; 95% confidence interval [CI], 1.37–6.22) and hospitalization within the previous 90 days (OR, 3.75; 95% CI, 1.90–7.41). ADL disability prior to admission (risk ratio [RR], 1.82; 95% CI, 1.17–2.84) and a high pneumonia severity index score upon admission (RR, 2.20; 95% CI, 1.37–3.65) were risk factors for new detection of MRSA. ConclusionsSeveral risk factors were found to be associated with MRSA carriage and/or its new detection, based on the sputum samples from patients admitted with pneumonia. These factors may be indicators for selective surveillance and the early implementation of infection control measures.

Nasal Methicillin-Resistant Staphylococcus aureus Carriage Among Foreign Workers Recruited to Taiwan From Southeastern Asian Countries.

BackgroundIn 2012, we identified the dissemination of methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST)45 strain in 14 nursing homes in Taiwan and foreign nurse workers, a significant risk factor for MRSA carriage. We conducted this study to understand MRSA carriage and molecular characteristics among foreign workers recruited from Southeastern Asian countries.MethodsA cross-sectional study involving a total of 1935 foreign workers—929 (arrival group) and 1006 (staying group)—from Vietnam (n = 843), Indonesia (n = 780), the Philippines (n = 239), and Thailand (n = 70) were conveniently recruited during upon-arrival and regular health examination in a regional hospital. A nasal swab was obtained from each participant for detection of MRSA.ResultsOverall, MRSA carriage rate was 2.72%, with 2.26% for arrival group and 3.18% for staying group, and 4.74% for Vietnamese, 1.28% for Indonesians, 1.26% for Filipino, and none for Thai workers. Pulsotype AK/ST45 (57%) and pulsotype AX/ST188 (14%) were the top 2 dominant clones for the arrival group, whereas pulsotype D/ST59 (41%) (an endemic community clone in Taiwan) and pulsotype AK/ST45 (19%) were predominant for the staying group. A significant decrease of pulsotype AK/ST45 from 57% to 19% (P = .007) and increase of pulsotype D/ST59 from 4.8% to 41% (P = .004) were found between the arrival and the staying groups.ConclusionsApproximately 3% of foreign workers recruited from Southeastern Asian countries to Taiwan were colonized with MRSA, including the ST45 strain. However, the MRSA isolates from workers staying in Taiwan were mostly a locally endemic clone and genetically different from those identified from workers on arrival.

Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among undocumented migrants and uninsured legal residents in Amsterdam, the Netherlands: a cross-sectional study

BackgroundNasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) is associated with an increased risk of infection. Colonization with MRSA is observed in < 1% of the general Dutch population. Increased risk for MRSA carriage is known to occur in several key groups, one of which is asylum seekers. However, little is known about MRSA carriage among undocumented migrants and uninsured legal residents. This study aimed to determine the prevalence of nasal MRSA carriage among these groups in Amsterdam, the Netherlands.MethodsIn this cross-sectional study, between October 2018 and October 2019, undocumented migrants and uninsured legal residents aged 18 years or older who were able to understand one of the study languages were recruited at an NGO health care facility in Amsterdam, the Netherlands, for general practitioner (GP) consultations. Participants were asked questions on demographics, migration history, antibiotic use and other possible risk factors for MRSA carriage and were screened for nasal MRSA carriage by selective culturing e-swabs. Characteristics of MRSA-negative and MRSA-positive participants were compared using univariable logistic regression analysis with Firth’s correction.ResultsOf the 3822 eligible patients, 760 were screened for nasal MRSA carriage (19.9%). Of the 760 participants, over half were male (58%; 442/760) and originated mainly from Africa (35%; 267/760), Asia (30%; 229/760) and North or South America (30%; 227/760). In total, 705/760 participants (93%) were undocumented migrants and 55/760 (7%) were uninsured legal residents of Amsterdam. The overall prevalence of nasal MRSA carriage was 2.0% (15/760) (95%CI 1.1 to 3.2%), with no difference between undocumented migrants (14/705) (2.0, 95%CI 1.1 to 3.3%) and uninsured legal residents (1/55) (1.8, 95%CI 0.1 to 9.7%). Genotyping showed no clustering of the 15 isolates. MRSA carriage was not associated with sociodemographic, migration history or other possible risk factors. Nevertheless, this study had limited power to detect significant determinants. Three participants (3/15; 20%) harbored Panton-Valentine leukocidin (PVL)-positive isolates.ConclusionEven though our study population of undocumented migrants and uninsured legal residents had a higher prevalence of nasal MRSA carriage compared to the general Dutch population, the prevalence was relatively low compared to acknowledged other high-risk groups.

Prevalence and Risk Factors for Positive Nasal Methicillin-Resistant Staphylococcus aureus Carriage Among Orthopedic Patients in Korea.

Methicillin-resistant Staphylococcus aureus (MRSA) causes purulent skin and soft tissue infections as well as other life-threatening diseases. Recent guidelines recommend screening for MRSA at the time of admission. However, few studies have been conducted to determine the prevalence and risk factors for MRSA colonization. A prospective data collection and retrospective analysis was performed. MRSA screening tests were performed using nasal swabs in patients enrolled between January 2017 and July 2018. Demographic data, socio-economic data, medical comorbidities, and other risk factors for MRSA carriage were evaluated among 1577 patients enrolled in the study. The prevalence of MRSA nasal carriage was 7.2%. Univariate regression analysis showed that colonization with MRSA at the time of hospital admission was significantly related to patient age, body mass index, smoking, alcohol, trauma, recent antibiotic use, and route of hospital admission. Multiple logistic regression analysis for the risk factors for positive MRSA nasal carriage showed that being under- or overweight, trauma diagnosis, antibiotic use one month prior to admission, and admission through an emergency department were related to MRSA colonization. This study highlights the importance of a preoperative screening test for patients scheduled to undergo surgery involving implant insertion, particularly those at risk for MRSA.

Prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus in patients at hospital admission in The Netherlands, 2010–2017: an observational study

ObjectivesWe determined the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage upon hospital admission, among patients who were screened preoperatively for nasal S. aureus carriage between 2010 and 2017. We also aimed to evaluate the prevalence of MRSA carriers without the standard risk factors. MethodsWe conducted an observational study to determine the prevalence of MRSA nasal carriage among patients who were screened preoperatively for nasal S. aureus carriage between 2010 and 2017. Samples of cardiothoracic patients were tested by polymerase chain reaction (PCR), other samples were cultured using chromogenic agar plates. A Poisson regression model with robust error variance was used to assess whether there was a trend in the prevalence of MRSA over time. ResultsIn total, 31 093 nasal swabs were obtained from 25 660 patients. Three-hundred and seventy-five swabs (1.2%) had an invalid result. Therefore, 30 718 swabs (98.8%) were included in our analysis. Overall, S. aureus was detected in 7981/30 718 patients (26.0% 95% CI 25.5–26.5%) of whom 41 were MRSA (0.13% 95% CI 0.10–0.18%). The MRSA prevalence varied from 0.03% to 0.17% over the years without evidence of a changing trend over time (p = 0.40). Results of the questionnaire revealed that 30 of the 41 patients (73.2%) had no known risk factors for MRSA carriage (0.10%; 95% CI 0.07–0.14%). ConclusionOur study revealed a sustained low prevalence of MRSA carriage upon hospital admission over 7 years. This supports the effectiveness of the Dutch Search and Destroy policy, in combination with a restrictive antibiotic prescription policy.

Cocaine Inhalation as a Risk Factor of Methicillin-Resistant Staphylococcus aureusNasal Colonization for Subjects Attending a Mexican Clinic

Background: Since Fleming detected growth inhibition in S. aureus mouldy culture plates, bacteria and humans have come a long way in the antibiotic resistance race. The increasing incidence of community-associated MRSA (Methicillin-Resistant Staphylococcus aureus) led the scientific community to identify risk factors for its carriage. Somers et al. obtained specimens from subjects attending a methadone clinic, and could not correlate inhalation of cocaine with nasal carriage. This study aims to gather data on the subject to determine if inhaling cocaine has an effect on MRSA carriage. Methods & Materials: For a 16-month period, patients attending our emergency unit were asked if they had ever inhaled cocaine. Those who had, were asked to respond a questionnaire regarding substance use and medical factors. Subjects with imprisonment, recent antibiotic use, hospitalization in the previous year, intravenous drug use, diabetes, HIV infection, renal or heart disease were excluded. Nasal, pharyngeal and inguinal swabs were obtained and the samples were plated on Mannitol Salt agar and incubated. S. aureus specimens were tested for susceptibility using the VITEK2 system and cefoxitin disk screen test. The study was designed so that variables were compared between those subjects with and without MRSA colonization using Pearson's Chi-squared test. All variables of interest were to be considered in a logistic regression analysis. Due to the lack of information regarding MRSA colonization in our local population, the authors decided to recruit non illegal drug users as matched controls. Results: Out of 150 specimens submitted for culture and identification, zero grew MRSA. Methicillin-sensitive S. aureus (MSSA) carriage had a 28% prevalence in the studied group (32% for matched controls). Out of the MSSA isolates, 11% were found exclusively in the inguinal samples. Males composed 92% of the subjects, with a mean age of 31 years. Only 56% of them had at least secondary education and 28% lived in overcrowded conditions. Due to the absence of MRSA isolates it was impossible to perform a logistic regression analysis. Conclusion: Our findings indicate that, in our community, inhaling cocaine does not represent a risk factor for MRSA carriage. Continued vigilant surveillance for carriage and infection among this population group is vital.

Opioid and amphetamine dependence is associated with methicillin-resistant Staphylococcus aureus (MRSA): An epidemiological register study with 73,201 Swedish in- and outpatients 1997–2013

Background: While methicillin-resistant Staphylococcus aureus (MRSA) is increasing in prevalence globally, Sweden is still a low-prevalence country enabling studies on the natural MRSA spread in subpopulations unaffected by a surrounding highly infected population. Substance dependence and injection drug use have been risk factors for MRSA carriage and infection in other countries. In this retrospective, longitudinal register study, we investigated MRSA epidemiology 1997–2013 in opioid and amphetamine-dependent individuals, in comparison with alcohol-dependent subjects.Methods: Data from the national Swedish in- and outpatients registers included 73,201 individuals from 1997, 1999, 2004, 2009 and 2013. We analyzed substance use disorder and demographic predictors for MRSA using generalized estimating equations.Results: The main finding was that both opioid (adjusted odds ratio [AOR] = 2.82; 95% confidence interval [CI] = 2.16, 3.67) and amphetamine dependence (AOR = 2.71; 95% CI = 1.70, 4.16) were significantly associated with MRSA diagnosis compared with alcohol dependence, when adjusting for age, sex and year.Conclusions: These findings are of value to understand the dynamics of MRSA epidemiology among substance dependent persons with presumably low socioeconomic status and potential injection drug use, and implicate repeated surveillance of MRSA among these patients.

Risk factors for methicillin-resistant Staphylococcus aureus carriage among residents in 7 nursing homes in Shanghai, China

Nursing home residents are a population at risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage, but few data about MRSA in this setting in Shanghai are available. The aim of this study is to determine the prevalence and risk factors for MRSA carriage in nursing home residents in Shanghai, China. Four hundred forty-three residents from 7 nursing homes in Shanghai, China, participated in this study; nasal and axillary swabs were obtained from these residents. Laboratory identification for S aureus and antimicrobial susceptibility testing were performed when isolated. Data, including individual resident characteristics and nursing home characteristics, were collected and analyzed. Of the 443 participating residents, 99 (22.3%) and 45 (10.2%) residents were colonized by S aureus and MRSA, respectively. Previous hospitalization (odds ratio [OR], 2.564; 95% confidence interval [CI], 1.214-5.415; P = .014), presence of an invasive device (OR, 3.455; 95% CI, 1.678-7.113; P = .001), chloramphenicol therapy (OR, 7.672; 95% CI, 1.807-32.580; P = .006), and macrolides therapy (OR, 2.796; 95% CI, 1.056-7.403; P = .038) were independent risk factors for MRSA colonization. Low expenditure per month and less good sanitary condition also increased the risk for MRSA colonization. Our study suggests that nursing homes are significant reservoirs for MRSA. Implementation of infection control strategies must be given high priority in nursing homes to fight the high prevalence of MRSA, and increased convenience and feasibility should also be realized with these control strategies for MRSA colonization.

Staphylococcus aureus in former Portuguese colonies from Africa and the Far East: missing data to help fill the world map

The aim of the present study was to determine the prevalence and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage among patients and healthcare workers in Angola (ANG), São Tomé and Príncipe (STP), Cape Verde (CV) and East Timor (ET), and to characterize the antimicrobial susceptibility, virulence content and population structure of all S. aureus. Despite the importance of MRSA as a major human pathogen, data from these former Portuguese colonies in Africa and Asia are scarce. A total of 2065 nasal swabs recovered between 2010–14 were included in the study. Antimicrobial susceptibility testing and molecular characterization of S. aureus showed: (i) a very high MRSA prevalence in ANG (61.6%), moderate in STP (25.5%), low in CV (5.6%) and null in ET; (ii) a high prevalence of Panton–Valentine leukocidin in STP (36.8%), ET (29.2%) and CV (28.3%) contrasting with ANG (7.9%); (iii) ST5-SCCmecIVa, ST8-IV/V and ST5-VI were the major MRSA clones in ANG (65.2%), STP (44.8%) and CV (50%), respectively; (iv) a high resistance to trimethoprim-sulfamethoxazole in ANG (66.5%) and STP (50.9%), to rifampin in ANG (77.3%), and to tetracycline in STP (26.3%) and ET (20.8%); (v) three major methicillin-susceptible S. aureus clones (ST15, ST508, ST152) were present in all four countries. Age <18 years (OR 2.03, 95% CI 1.24–3.31), previous surgery (OR 2.45, 95% CI 1.24–4.83), no smoking (OR 4.04, 95% CI 1.05–15.50), and longer hospitalization (OR 2.53, 95% CI 1.49–4.28) were risk factors for MRSA carriage. This study provided the first comprehensive overview on MRSA in former Portuguese colonies in Africa and Asia, missing data in the world map.

Variable performance of models for predicting methicillin-resistant Staphylococcus aureus carriage in European surgical wards.

BackgroundPredictive models to identify unknown methicillin-resistant Staphylococcus aureus (MRSA) carriage on admission may optimise targeted MRSA screening and efficient use of resources. However, common approaches to model selection can result in overconfident estimates and poor predictive performance. We aimed to compare the performance of various models to predict previously unknown MRSA carriage on admission to surgical wards.MethodsThe study analysed data collected during a prospective cohort study which enrolled consecutive adult patients admitted to 13 surgical wards in 4 European hospitals. The participating hospitals were located in Athens (Greece), Barcelona (Spain), Cremona (Italy) and Paris (France). Universal admission MRSA screening was performed in the surgical wards. Data regarding demographic characteristics and potential risk factors for MRSA carriage were prospectively collected during the study period. Four logistic regression models were used to predict probabilities of unknown MRSA carriage using risk factor data: “Stepwise” (variables selected by backward elimination); “Best BMA” (model with highest posterior probability using Bayesian model averaging which accounts for uncertainty in model choice); “BMA” (average of all models selected with BMA); and “Simple” (model including variables selected >50% of the time by both Stepwise and BMA approaches applied to repeated random sub-samples of 50% of the data). To assess model performance, cross-validation against data not used for model fitting was conducted and net reclassification improvement (NRI) was calculated.ResultsOf 2,901 patients enrolled, 111 (3.8%) were newly identified MRSA carriers. Recent hospitalisation and presence of a wound/ulcer were significantly associated with MRSA carriage in all models. While all models demonstrated limited predictive ability (mean c-statistics <0.7) the Simple model consistently detected more MRSA-positive individuals despite screening fewer patients than the Stepwise model. Moreover, the Simple model improved reclassification of patients into appropriate risk strata compared with the Stepwise model (NRI 6.6%, P = .07).ConclusionsThough commonly used, models developed using stepwise variable selection can have relatively poor predictive value. When developing MRSA risk indices, simpler models, which account for uncertainty in model selection, may better stratify patients’ risk of unknown MRSA carriage.

Dissemination of methicillin-resistant Staphylococcus aureus sequence type 45 among nursing home residents and staff in Taiwan

Unlike hospitals or the community, nursing homes provide a unique healthcare environment for patients. There have been no reports regarding methicillin-resistant Staphylococcus aureus (MRSA) carriage among nursing home residents and staff in Taiwan. From May to November 2012, a total of 523 subjects, including 360 residents and 163 staff, in 14 nursing homes in Taiwan were surveyed for nasal MRSA carriage. Overall, the nasal MRSA carriage rate was 20.1%, with 20.3% for residents and 19.6% for staff. For residents, age >60 years (adjusted OR 2.268; 95% CI 1.185–4.342; p 0.013) and the presence of chronic wounds (adjusted OR 2.449; 95% CI 1.082–5.544; p 0.032) were the significant risk factors for MRSA carriage in multivariate models. Among the 105 MRSA isolates, 11 pulsed-field gel electrophoresis (PFGE) patterns were identified, except for five isolates untypeable by SmaI digestion, with one major pattern; nine isolates (8.6%) possessed staphylococcal cassette chromosome (SCCmec) type II or III, 66 isolates type IV or V, and 21 isolates unidentified types. The clone characterized as PFGE pattern BM sequence type 45 was the most common clone, accounting for 50% of the isolates, and was multiresistant, including to ciprofloxacin. Intra-institutional and inter-institutional transmission of MRSA was documented by molecular methods. It was shown conclusively that one-fifth of residents and staff in nursing homes in Taiwan harboured MRSA, mostly ST45 strains, in their nares. Intra-institutional and inter-institutional transmission of MRSA was documented.

Prevalence, risk factors, and epidemiology of methicillin-resistant Staphylococcus aureus carried by adults over 60 years of age.

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in the community in Portugal is not completely understood. To evaluate S. aureus and MRSA carriage among the elderly, we conducted a large cross-sectional study between April 2010 and December 2012. A total of 3,361 adults over 60years of age were screened for S. aureus nasopharyngeal and oropharyngeal carriage. MRSA were characterized by staphylococcal cassette chromosome mec (SCCmec) typing, spa typing, multilocus sequence typing (MLST), and tested for the presence of Panton-Valentine leukocidin (PVL). Risk factors for MRSA carriage were identified by multiple logistic regression analysis. The prevalence of S. aureus and MRSA carriage among the elderly was 20.1% and 1.8%, respectively. The risk of being an MRSA carrier was higher among the elderly living in retirement homes [odds ratio (OR) = 2.90, 95 % confidence interval (CI): 1.48-5.48] and those that had been hospitalized in the previous year (OR = 2.64, 95 % CI: 1.47-4.58). Among the 62 MRSA isolates, 64.5% were multidrug-resistant and none carried PVL. Most MRSA (82.3%) were related to three hospital-associated (HA-MRSA) clones disseminated in Portugal: ST105-II (New York/Japan clone; 43.5%), ST5-IVc (Pediatric clone; 19.4%), and ST22-IVh (EMRSA-15 clone; 19.4%). The New York/Japan and Pediatric clones were significantly associated with carriers living in retirement homes, while the EMRSA-15 clone was associated with carriers that had been hospitalized. We conclude that the elderly population in Portugal is essentially free of MRSA. Given the current European societal challenges for a healthy active aging, these results are of importance to healthcare professionals and public authorities to decide on strategies to promote health in this age group.

Screening for methicillin-resistant Staphylococcus aureus carriers among individuals exposed and not exposed to the hospital environment and their antimicrobial sensitivity pattern

Aims: This study evaluated the influence of exposure to the hospital environment on methicillin-resistant Staphylococcus aureus (MRSA) carriage. The antibiograms of the MRSA isolates were examined. Materials and Methods: Nasal, throat, and web-space swabs were collected from 119 nursing students of the age group 18-23 years (exposed group) and 100 age-matched pharmacy students (nonexposed group). S. aureus was identified and antibiogram obtained as per Clinical and Laboratory Standards Institute (CLSI) guidelines. MRSA was detected by cefoxitin disc diffusion test and by growth on oxacillin screen agar as per CLSI guidelines. The presence of the mecA gene was confirmed by conventional polymerase chain reaction. Results: The MRSA carrier rates were 11.8% and 4% in the exposed and nonexposed groups, respectively. Association of exposure to the hospital environment with MRSA colonization was statistically significant. All MRSA isolates showed sensitivity to netilmicin, linezolid, tetracycline, vancomycin and teicoplanin. Among the exposed group, 71.4% MRSA isolates were resistant to ciprofloxacin, 64.3% to cotrimoxazole, 64.3% to erythromycin, 28.6% to gentamicin and 21.4% to clindamycin. Among the nonexposed group, 75% MRSA isolates were resistant to ciprofloxacin, 25% to cotrimoxazole, 25% to erythromycin, 25% to gentamicin and 25% to clindamycin. Conclusion: Exposure to the hospital environment was found to be a significant risk factor for MRSA carriage. Hospital-acquired MRSA (HA-MRSA) isolates showed greater resistance toward antimicrobials compared with community-acquired MRSA (CA-MRSA) isolates. This highlights the need for the appropriate institution of pharmacotherapy in cases of HA-MRSA and CA-MRSA infections and control of transmission by carriers.

Medical and Household Characteristics Associated with Methicillin Resistant Staphylococcus aureus Nasal Carriage among Patients Admitted to a Rural Tertiary Care Hospital

BackgroundMethicillin resistant Staphylococcus aureus (MRSA) poses a threat to patient safety and public health. Understanding how MRSA is acquired is important for prevention efforts. This study investigates risk factors for MRSA nasal carriage among patients at an eastern North Carolina hospital in 2011.MethodsUsing a case-control design, hospitalized patients ages 18 – 65 years were enrolled between July 25, 2011 and December 15, 2011 at Vidant Medical Center, a tertiary care hospital that screens all admitted patients for nasal MRSA carriage. Cases, defined as MRSA nasal carriers, were age and gender matched to controls, non-MRSA carriers. In-hospital interviews were conducted, and medical records were reviewed to obtain information on medical and household exposures. Multivariable conditional logistic regression was used to derive odds ratio (OR) estimates of association between MRSA carriage and medical and household exposures.ResultsIn total, 117 cases and 119 controls were recruited to participate. Risk factors for MRSA carriage included having household members who took antibiotics or were hospitalized (OR: 3.27; 95% Confidence Interval (CI): 1.24–8.57) and prior hospitalization with a positive MRSA screen (OR: 3.21; 95% CI: 1.12–9.23). A lower proportion of cases than controls were previously hospitalized without a past positive MRSA screen (OR: 0.40; 95% CI: 0.19–0.87).ConclusionThese findings suggest that household exposures are important determinants of MRSA nasal carriage in hospitalized patients screened at admission.

Carriage of methicillin-resistant Staphylococcus aureus on admission to European rehabilitation centres-a prospective study

This study aimed to determine the prevalence of and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) carriage among patients newly admitted to rehabilitation centres. It is a prospective study examining MRSA carriage on admission to seven rehabilitation wards in four countries. Risk factors for MRSA carriage were analysed using univariate and multivariate analyses. A total of 1204 patients were studied. Among them, 105 (8.7%) had a positive admission MRSA screening result. The MRSA carriers were more likely to be male, to have had a recent stay in another long-term-care facility or >2 weeks acute-care hospital stay, history of colonization with MRSA, reduced level of consciousness, peripheral vascular disease and pressure sores. In multivariable logistic regression male gender (odds ratio (OR) 2.2, 95% confidence interval (CI) 1.4-3.6, p 0.001), history of MRSA positivity (OR 6.8, 95% CI 3.8-12.3, p <0.001), peripheral vascular disease (OR 2.5, 95% CI 1.2-5, p 0.013), recent stay in another long-term-care facility (OR 2.1, 95% CI 1.3-3.5, p 0.004), or long (>2 weeks) acute-care hospital stay (OR 1.9, 95% CI 1.2-3, p 0.004), remained significant risk factors for MRSA carriage. MRSA carriage is common on admission to rehabilitation centres but less so, than previously described in long-term-care facilities. Male gender, history of MRSA positivity, previous hospitalization and peripheral vascular disease may predict MRSA carriage, and may serve as indicators for using pre-emptive infection control measures.

Livestock-associated MRSA ST398 carriage in pig slaughterhouse workers related to quantitative environmental exposure

ObjectivesTo assess livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) carriage among workers in pig slaughterhouses and assess associated risk factors, including occupational exposure to LA-MRSA.MethodsA cross-sectional study in three Dutch pig slaughterhouses...

Potential for Pet Animals to Harbour Methicillin‐Resistant Staphylococcus aureus When Residing with Human MRSA Patients

Colonization by methicillin-resistant Staphylococcus aureus (MRSA) may be persistent in people and is horizontally transmissible. The scientific literature suggests that domestic pets may also participate in cross-transmission of MRSA within households. The objectives of this study were to evaluate the prevalence of and risk factors for MRSA carriage by pets residing in households with an MRSA-infected person. From 66 households in which an MRSA-infected patient resided, we screened 47 dogs and 52 cats using a swab protocol. Isolates from pets and humans were genotyped using two techniques and compared for concordance. Human participants completed a 22-question survey of demographic and epidemiologic data relevant to staphylococcal transmission. Eleven of 99 pets (11.5%) representing 9 (13.6%) of households were MRSA-positive, but in only six of these households were the human and animal-source strains genetically concordant. Human infection by strain USA 100 was significantly associated with pet carriage [OR = 11.4 (95% CI 1.7, 76.9); P = 0.013]. Yet, for each day of delay in sampling the pet after the person's MRSA diagnosis, the odds of isolating any type of MRSA from the pet decreased by 13.9% [(95% CI 2.6, 23.8); P = 0.017)]. It may be concluded that pets can harbour pandemic strains of MRSA while residing in a household with an infected person. However, the source of MRSA to the pet cannot always be attributed to the human patient. Moreover, the rapid attrition of the odds of obtaining a positive culture from pets over time suggests that MRSA carriage may be fleeting.

Prevalence of and Risk Factors for Methicillin-ResistantStaphylococcus aureusCarriage at Hospital Admission

To determine the prevalence of and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) carriage at the time of admission to our hospital, we screened the medical records of 1,128 patients for demographic and clinical data. The antimicrobial resistance pattern and genotype of MRSA isolates were studied. The prevalence of MRSA carriage at hospital admission was 1.4%. Older patients and patients previously admitted to healthcare centers were the most likely to have MRSA carriage at admission.

Prevalence of and risk factors for MRSA carriage in companion animals: a survey of dogs, cats and horses

We investigated the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage in a convenience sample of purposely selected populations of dogs, cats and horses in the Greater London area. Swabs from carriage sites were pooled, enriched and processed by standard bacteriological methods. The presence of nuc and mecA was confirmed for MRSA. Risk factors were investigated among veterinary treatment group animals using exact logistic regression analysis. Twenty-six (1.53%) MRSA carriers were identified in the 1692 animals (15/704 dogs, 8/540 cats, 3/152 horses). Animals presenting for veterinary treatment more frequently carried MRSA than healthy animals (OR 7.27, 95% CI 2.18-24.31, P<0.001). Concurrent carriage of non-MRSA coagulase-positive staphylococci was associated with MRSA carriage (OR 0.088, 95% CI 0.016-0.31, P<0.001); none of the other 13 putative risk factors was significant. MRSA carriage was rare in the selected companion animal populations. The absence of typical risk factors indicates that companion animals act as contaminated vectors rather than as true reservoirs.