Prevalence Of Methicillin-resistant Staphylococcus Aureus Colonization Research Articles

Prevalence of Methicillin Resistant Staphylococcus aureus Colonisation in Patients undergoing Total Joint Arthroplasty: A Retrospective Observational Study

Introduction: Methicillin Resistant Staphylococcus aureus (MRSA) presents a significant, yet preventable, complication in Total Joint Arthroplasties (TJAs). Surgical Site Infections (SSIs) of prosthetic joints resulting from MRSA lead to substantial patient morbidity, mortality, and impose a significant burden on healthcare budgets. One method to mitigate these risks is to screen for MRSA colonisation prior to elective surgeries. The prevalence of MRSA colonisation in nasal mucosa ranges from 0.18-7.2% in different patient populations, with a nosocomial prevalence of 1.7%. Aim: To determine the prevalence of MRSA colonisation in all patients undergoing elective TJA, including Total Hip Replacement (THR) or Total Knee Replacement (TKR). Materials and Methods: A retrospective observational study was conducted on a total of 407 patients scheduled for elective TJAs. Data from 407 patients who underwent elective TJA between January 2020 and December 2022 (a period of three years) were selected for the study. Data compilation and analysis of the study subjects were performed retrospectively until March 2023 at the Sanjay Gandhi Institute of Trauma and Orthopaedics, a tertiary care Orthopaedic centre in Bengaluru, Karnataka, India. The study subjects were screened for MRSA colonisation through nasal swab culture and sensitivity. Patients with positive MRSA culture results were treated with decolonisation therapy, which involved the local application of 2% mupirocin and chlorhexidine body wash for five days. Descriptive data analytics were employed in the study, and tables were generated using Microsoft Word 2010 and Microsoft Excel 2010 (Microsoft Corp, Redmond, WA, USA). Results: The prevalence rates of MRSA nasal colonisation were n1=8 (8.42%), n2=2 (2%), and n3=16 (7.55%) for the years 2020 (n1), 2021 (n2), and 2022 (n3), respectively, at the centre. The period prevalence rate of MRSA colonisation in the nasal mucosa over three years was N=26 (6.4%). Conclusion: The present study revealed a high period prevalence of MRSA colonisation (6.4%) in patients undergoing TJAs. Therefore, all elective TJAs should undergo MRSA screening and decolonisation using 2% intranasal mupirocin and daily chlorhexidine body wash for five days as a successful treatment modality for all patients with MRSA-positive nasal colonisation. This approach helps prevent postoperative SSIs caused by MRSA.

The Impact of MRSA Colonization on Healthcare-Associated Infections in Long-Term Care Facility Residents: A Whole-Genome Sequencing-Based Study.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization has been considered a risk factor for the development of infection, however, there are no studies that have compared the colonizing and infecting strains using whole-genome sequencing (WGS). The aim of this study is to determine the prevalence of and risk factors for MRSA colonization among long-term care facilities (LTCF) residents of Tenerife (Spain), and to analyze the epidemiological relationship between the colonizing and infecting strains using WGS. A point-prevalence study was carried out at 14 LTCFs in Tenerife from October 2020 to May 2021. Nasal swabs were cultured for MRSA. Colonized residents were followed up for two years. A phylogenetic comparison between colonization and infection strains was performed using WGS. A total of 764 residents were included. The prevalence of colonization by MRSA was 28.1% (n = 215), of which 12 (5.6%) subsequently developed infection. A close genetic relationship between colonization and infection isolates was found in three of the four (75%) residents studied. Our study confirms that colonized residents can develop serious MRSA infections from the same nasal colonization strain. Given the high prevalence of MRSA colonization in these centers, it is necessary to implement strategies with preventive measures to avoid the development of infection and the transmission of MRSA.

Methicillin-Resistant Staphylococcus aureus Colonization in Intensive Care and Burn Units: A Narrative Review.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common hospital-acquired pathogen and can cause a wide spectrum of infections. In recent years, MRSA has emerged as a significant public health concern, particularly in hospitals. Intensive care units (ICUs) and burn units are high-risk areas for hospital-acquired MRSA infections, which can lead to increased morbidity, mortality, and healthcare costs. MRSA exhibits resistance to multiple antibiotics and can cause serious infections, including but not limited to pneumonia, endocarditis, and cutaneous infections, particularly in patients with burn injuries. The prevention and effective management of MRSA infections in both burn patients and those in ICUs is crucial, with strategies like isolation, regular disinfection, and prophylactic intranasal mupirocin. Early diagnosis of MRSA infection and isolation of patients is vital to prevent the spread of MRSA. Implementation of prevention strategies faces many challenges, such as cost, and the most successful infection management practices are still debated. This review has highlighted the substantial concern of MRSA colonization in intensive care and burn units. MRSA poses a significant risk to vulnerable patients, influenced by factors such as compromised immunity and invasive procedures. The prevalence of MRSA colonization varies, influenced by regional factors and infection control practices. Combating MRSA requires a multifaceted approach, including stringent infection control measures and education for healthcare workers and patients. As we move forward, continued research and cooperation are essential to reduce the burden of MRSA in these critical care settings.

The Epidemiology of Animal-Associated Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) remains an important etiological factor of human and animal infectious diseases, causing significant economic losses not only in human healthcare but also in the large-scale farming sector. The constantly changing epidemiology of MRSA observed globally affects animal welfare and raises concerns for public health. High MRSA colonization rates in livestock raise questions about the meaning of reservoirs and possible transmission pathways, while the prevalence of MRSA colonization and infection rates among companion animals vary and might affect human health in multiple ways. We present the main findings concerning the circulation of animal-associated MRSA (AA-MRSA) in the environment and factors influencing the direction, mechanisms, and routes of its transmission. Studies have shown it that S. aureus is a multi-host bacterial pathogen; however, its adaptation mechanisms enabling it to colonize and infect both animal and human hosts are still rarely discussed. Finally, we elaborate on the most successful strategies and programs applied limiting the circulation of AA-MRSA among animals and humans. Although MRSA strains colonizing animals rarely infect humans, they undergo host-adaptive evolution enabling them to spread and persist in human populations.

Genomic Analysis of Community Transmission Networks for MRSA Among Females Entering a Large Inner-city Jail.

BackgroundIt is unclear if there are differences in methicillin-resistant Staphylococcus aureus (MRSA) risk between sexes in high-risk populations.MethodsFemales incarcerated at the Cook County Jail were enrolled within 72 hours of intake. Surveillance cultures (nares, throat, groin) were collected to determine the prevalence of MRSA colonization. A survey was administered to identify colonization predictors. Univariate and multivariate analyses were performed to identify predictors of colonization at intake. Genomic sequencing was performed on MRSA colonization and archived clinical isolates.ResultsTwo hundred fifty women were enrolled (70% African American, 15% Hispanic), with 70% previously in jail. The prevalence of MRSA colonization at intake was 20%, with 42% of those colonized solely in the throat or groin. Univariate predictors of MRSA colonization at entrance were illicit drug use, unstable housing, engaging in anal sex, recent exchange of sex for drugs/money, and a higher number of recent sexual partners. With multivariate adjustment for race/ethnicity, use of needles for illicit drugs was a significant predictor of MRSA. Use of illicit drugs was also associated with inclusion in a genomic cluster. Nares colonization was significantly associated with not being in a genomic cluster (18.8% vs 78.6%; P < .001), whereas exclusive extranasal colonization was associated (odds ratio, 15.89; P < .001).ConclusionsWe found that a high proportion (20%) of females entered jail colonized with MRSA, suggesting that previously reported sex disparities of a lower risk in women may not apply to high-risk populations. Our findings suggest high-risk activities or venues in the community for MRSA, with potential for directing sex-specific interventions.

1138. Utility of Methicillin-resistant Staphylococcus aureus Nares Screening in Hospitalized Children With Acute Infectious Disease Syndromes

BackgroundEmpirical antibiotic regimens frequently include treatment for methicillin-resistant Staphylococcus aureus (MRSA). Studies in adults with pneumonia support the use of a negative MRSA nares screening (MNS) to help de-escalate antibiotic therapy. Comparable pediatric data in the literature is scarce. We aimed to evaluate the use of MNS for antibiotic de-escalation in hospitalized children (< 18 years) at a tertiary children’s hospital. MethodsA retrospective chart review was conducted of pediatric inpatients (January 01, 2015 to December 31, 2020) with a presumed infectious diagnosis who had a PCR-based MNS test and a clinical culture (i.e. site of infection or blood) performed as part of their diagnostic work up. Those who were screened >5 days since admission or > 48 hours since start of MRSA-active antimicrobials, and those who had antibiotic treatment withdrawn after 48 hours because of negative cultures were excluded. ResultsA total of 101 children were included with a median age (range) of 2 years (0-17) and about half (n=57, 56.4%) were male. Top three diagnosis groups were skin and soft tissue infections (n=33, 32.7%), toxin-mediated syndromes (n=21, 20.8%), and osteoarticular infections (n=13, 12.9%). Pneumonia accounted for only six (5.9%) patients. The prevalence of nasal MRSA colonization was 6.9% (n=7). The sensitivity of the MNS test to predict a MRSA infection was 42.9% with a specificity of 95.7%. The positive predictive value (PPV) and negative predictive values (NPV) were 42.9% and 95.7%, respectively. In about half (55/95, 57.9%) of patients initiated on anti-MRSA therapy, these agents were discontinued during the admission. A quarter (n=14, 25.5%) were de-escalated based on the negative MNS test alone, and another third (n=21, 38.2%) after negative MNS test and negative culture results became available. ConclusionPediatric providers at this institution have started to use the MNS to help limit anti-MRSA therapy. We noted a high NPV which suggests that MNS may be useful for timely de-escalation of anti-MRSA therapy and thereby a useful antimicrobial stewardship tool for hospitalized children. Prospective studies to evaluate the utility of MNS for the various infectious syndromes are warranted.Disclosures All Authors: No reported disclosures

Cumulative Incidence of Methicillin-Resistant Staphylococcus aureus Colonization in Resident Physicians Over Time.

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) can colonize up to 14.5% of healthcare workers (HCWs). The colonization rate of HCWs or the hospital setting that contributes most to MRSA colonization is less clear. In this study, we studied new resident physicians (PGY-1), as a model for HCWs, to measure their colonization rate and hypothesized that the incidence of colonization would increase during their first year.MethodologyWe prospectively enrolled PGY-1 residents of multiple specialties at three academic medical centers. After obtaining informed consent, PGY-1 residents were tested for MRSA in June 2019 before starting any clinical rotations and then retested every three to four months thereafter. The coronavirus disease 2019 pandemic forced us to end the study early. If MRSA-positive, residents were treated with 2% mupirocin and retested for a cure. For comparison, upper-level residents (PGY-2-5) were also enrolled to obtain a baseline prevalence of colonization.ResultsWe enrolled 80 PGY-1 and 81 PGY-2-5 residents in the study. The baseline prevalence of MRSA colonization was 4.94% (4/81) in PGY-2-5 residents and 2.50% (2/80) for new PGY-1 residents; however, this was not statistically significant (p = 0.68). The cumulative yearly incidence of developing MRSA colonization in PGY-1 residents was 4.51%. MRSA colonization was successfully treated in 75% of cases.ConclusionsPGY-1 residents had a lower MRSA colonization rate compared to PGY-2-5 residents, although this was not statistically significant. PGY-1 residents had a small incidence of developing MRSA colonization while working in the hospital. Further research is needed to determine if this is clinically relevant to HCWs or their patients.

Vertical transmission of methicillin-resistant Staphylococcus aureus at delivery and its clinical impact: An observational, prospective cohort study.

Methicillin-resistant Staphylococcus aureus (MRSA) infection has a significant clinical impact on both pregnant women and neonates. The aim of this study was to assess accurately the vertical transmission rate of MRSA and its clinical impacts on both pregnant mothers and neonates. We conducted a prospective observational cohort study of 898 pregnant women who were admitted to our department and 905 neonates from August 2016 to December 2017. MRSA was cultured from nasal and vaginal samples taken from the mothers at enrollment and from nasal and umbilical surface swabs taken from neonates at the time of delivery. We examined the vertical transmission rate of MRSA in mother-neonate pairs. We used multivariable logistic regression to identify risk factors for maternal MRSA colonization and maternal/neonatal adverse outcomes associated with maternal MRSA colonization. The prevalence of maternal MRSA colonization was 6.1% (55 of 898) at enrollment. The independent risk factors were multiparity and occupation (healthcare provider) (odds ratio [OR] 2.35, 95% confidence interval [CI] 1.25-4.42 and OR 2.58, 95% CI 1.39-4.79, respectively). The prevalence of neonatal MRSA colonization at birth was 12.7% (7 of 55mother-neonate pairs) in the maternal MRSA-positive group, whereas it was only 0.12% (one of 843 pairs) in the maternal MRSA-negative group (OR 121, 95% CI 14.6-1000). When maternal vaginal samples were MRSA-positive, vertical transmission was observed in four of nine cases (44.4%) in this study. Skin and soft tissue infections developed more frequently in neonates in the maternal MRSA-positive group than in the MRSA-negative group (OR 7.47, 95% CI 2.50-22.3). The prevalence of MRSA in pregnant women was approximately 6%. Vertical transmission caused by maternal vaginal MRSA colonization was observed in four of nine cases (44.4%). Although our study includes a limited number of maternal MRSA positive cases, the vertical transmission of MRSA may occur in up to 44% of neonates of mothers with vaginal MRSA colonization. Maternal MRSA colonization may be associated with increased development of skin and soft tissue infections in neonates via vertical transmission.

Molecular Evaluation of Traditional Chicken Farm-Associated Bioaerosols for Methicillin-Resistant Staphylococcus aureus Shedding.

The outbreak of airborne pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) through bioaerosol, and their molecular characterization around domestic poultry farming areas, was not completely understood. This imposes risk of a MRSA-associated health threat for the relevant livestock food production units. To address this issue, the present study investigated the role of bioaerosol in transmitting MRSA strains in poultry house settings by combining molecular typing, phylogenetic classification, antibiotic susceptibility, and virulence gene distribution patterns. The present study highlights that all 18 bioaerosol and stool samples collected were MRSA positive, with a unique set of virulence factors. Out of 57 isolated MRSA isolates, 68.4% and 19.3% consisted of SCCmec I and IV elements, respectively, which are commonly linked with hospital-acquired and livestock-associated MRSA strains. It is worth noting that the exfoliative toxin eta and etb genes were carried by 100% and 70.2% of all isolates, respectively. Only 17.5% of strains showed the presence of enterotoxin entC. These MRSA isolates were resistant to chloramphenicol (C), ciprofloxacin (CIP), clindamycin (DA), erythromycin (E), and tetracycline (T), signifying their multi-drug resistance traits. A cluster of phylogenetic analysis described that 80.7% and 15.8% of total isolates belonged to Staphylococcus aureus protein A (spa) type t002 and t548. Whereas 3.5% were reflected as a new spa type. Additionally, as per the chi-squared test score value, these two spa types (t002 and t548) have a distribution correlation with HA-MRSA and LA-MRSA in all the samples (p < 0.005, chi-squared test; degree of freedom = 1). Ultimately, this study highlights the prevalence of MRSA colonization in the conventional poultry farm environment, showing the risk of bioaerosol transmission, which needs epidemiological attention and prevention strategies.

Staphylococcus aureus nasal colonization among dental health care workers in Northern Germany (StaphDent study)

Methicillin-resistant Staphylococcus aureus (MRSA) can colonize dental patients and students, however, studies on the prevalence of MRSA and methicillin-susceptible S. aureus (MSSA) among dental health care workers (DHCW) including use of personal protective equipment (PPE) are scarce. We conducted an observational study (StaphDent study) to (I) determine the prevalence of MRSA and MSSA colonization in DHCW in the region of Mecklenburg Western-Pomerania, Germany, (II) resolve the S. aureus population structure to gain hints on possible transmission events between co-workers, and (III) clarify use of PPE. Nasal swabs were obtained from dentists (n = 149), dental assistants (n = 297) and other dental practice staff (n = 38). Clonal relatedness of MSSA isolates was investigated using spa typing and, in some cases, whole genome sequencing (WGS). PPE use was assessed by questionnaire. While 22.3% (108/485) of the participants were colonized with MSSA, MRSA was not detected. MSSA prevalence was not associated with size of dental practices, gender, age, or duration of employment. The identified 61 spa types grouped into 17 clonal complexes and four sequence types. Most spa types (n = 47) were identified only once. In ten dental practices one spa type occurred twice. WGS data analysis confirmed a close clonal relationship for 4/10 isolate pairs. PPE was regularly used by most dentists and assistants. To conclude, the failure to recover MRSA from DHCW reflects the low MRSA prevalence in this region. Widespread PPE use suggests adherence to routine hygiene protocols. Compared to other regional HCW MRSA rates the consequent usage of PPE seems to be protective.

Methicillin Resistant Staphylococcus Aureus Carrier Status among Indian Healthcare Workers: A Systematic Review and Meta-Analysis

Infection with Methicillin Resistant Staphylococcus aureus (MRSA) is a threat to quality care in the hospital.Asymptomatic colonization of MRSA escalates the burden of infection. The rate of MRSA colonizationamong healthcare workers (HCW) is not homogenous across the globe. Even though there are individualstudy reports on MRSA colonization, no pooled data is available in India. Therefore, it is important toevaluate the problem of MRSA colonization to develop a policy on preventive measures. We performeda systematic review and meta-analysis of MRSA carrier status among Indian HCWs using five databases(Scopus, PubMed-Medline, IndMed, CINAHL and Google-Scholar) from the articles published from 2008to 2017 (10 years). STATA 13.0 with metaprop package in STATA was used to find the rate of colonization.Among 2,349 HCWs, the pooled prevalence of MRSA colonization in throat, nose, axilla, palm, fingertipsand web-spaces was nine percent (CI 6% - 13%; p=0.001, I291.68%). Further, the forest plot of MRSAcolonization in nasal cavity alone was performed, and the prevalence of nasal colonization of MRSA among1,251 Indian HCWs was found to be 11% (CI 5-17%, p=0.001, I2 93.3%). The colonization rate is not veryhigh nor negligible. Therefore, the hospital administrator along with the hospital infection control committeeneeds to formulate a policy on periodic screening and decolonization of HCWs in high-risk areas.

Synergistic Effect of Combination Interventions for Methicillin-Resistant Staphylococcus aureus Transmission Control in Nursing Homes: A Computation Modelling Evaluation with Heterogeneous Contact Mixing.

The endemic threat of methicillin-resistant Staphylococcus aureus (MRSA) in nursing homes poses a serious and escalating challenge to public health administration in infection control. Nursing homes are considered as major reservoirs for MRSA colonization, with considerable high levels of colonization prevalence. We employed a computation model to evaluate effects of three intervention scenarios on MRSA colonization prevalence rate in nursing homes. Simulations were conducted using a deterministic compartmental model featuring heterogeneous contact matrix between residents and health-care workers (HCWs). Contact parameters were derived from a nursing home survey. Three intervention scenarios were simulated: (1) hand-hygiene compliance by HCWs, (2) screening-and-isolation upon admission, and (3) implementing both interventions at the same time. For every 10% reduction in average contamination duration in HCWs, the estimated average reduction in prevalence rate was 1.29 percentage point compared with the prevalence rate before the intervention was implemented. Screening-and-isolation intervention resulted in an average reduction of 19.04 percentage point in prevalence rate (S.D. = 1.58; 95% CI = 18.90–19.18). In intervention scenario 3, synergistic effects were observed when implementing hand-hygiene compliance by HCWs and screening-and-isolation together. Our results provide evidence showing that implementing multiple interventions together has a synergistic effect on colonization prevalence reduction.

Can preoperative screening for methicillin-resistant staphylococcus aureus effectively predict surgical site infections in spine surgeries?

Introduction: Hospital care-associated infections prolong hospital stay and thus increased financial burden, causes long-term disability and mortality in patients and can increase resistance of microorganisms to antimicrobials. Surgical site infections (SSIs) are the most frequent type of hospital care-associated infections in the developing countries. Staphylococcus is the most commonly isolated organism with methicillin-resistant Staphylococcus aureus (MRSA) posing a great threat. The most common human reservoir for S. aureus is the nares. We propose a study to evaluate the efficacy of preoperative screening of MRSA by nasal and throat culture by correlating it with postoperative SSI. Study Design: Prospective study. Purpose of the Study: 1. To determine the prevalence of MRSA colonization in a population of patients scheduled for elective spine surgery. 2. To determine whether preoperative nasal and throat swab cultures for MRSA are predictive of postoperative SSI in patients undergoing spine surgery. Materials and Methods: Two hundred and forty-eight patients who underwent spine surgery at Baby Memorial Hospital, Calicut, from December 2018 onward are included in this study. Patients who had spine surgeries for infections were excluded from the study. Patients who developed postoperative SSIs were cross-checked with preoperative data and analyzed whether the infecting organism is same as in the preoperative nasal and throat swab culture (if it is present). The significance of the correlation between preoperative nasal and throat swab culture and postoperative SSI are assessed statistically with Chi-square test. Discussion: Among the 248 patients in this study, preoperative nasal and throat swab culture yielded MRSA in 27 patients (nasal – 24, throat – 2, and both – 1). Out of 248 patients, 6 patients developed SSIs with MRSA, but none of them had MRSA in preoperative nasal or throat swab culture. Conclusion: Preoperative MRSA screening by throat and nasal swab is not routinely needed in spine surgery as it appears to carry no positive predictive value in postoperative SSIs.

Association between length of residence and prevalence of MRSA colonization among residents in geriatric long-term care facilities

BackgroundA high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization has been reported among residents in geriatric long-term care facilities (LTCFs). Some studies indicate that MRSA might be imported from hospitals into LTCFs via resident transfer; however, other studies report that high MRSA prevalence might be caused by cross-transmission inside LTCFs. We aimed to assess which factors have a large impact on the high MRSA prevalence among residents of geriatric LTCFs.MethodsWe conducted a cohort study among 260 residents of four geriatric LTCFs in Japan. Dividing participants into two cohorts, we separately analyzed (1) the association between prevalence of MRSA carriage and length of LTCF residence (Cohort 1: n = 204), and (2) proportion of residents identified as MRSA negative who were initially tested at admission but subsequently identified as positive in secondary testing performed at ≥2 months after their initial test (Cohort 2: n = 79).ResultsAmong 204 residents in Cohort 1, 20 (9.8%) were identified as positive for MRSA. Compared with residents identified as MRSA negative, a larger proportion of MRSA-positive residents had shorter periods of residence from the initial admission (median length of residence: 5.5 vs. 2.8 months), although this difference was not statistically significant (p = 0.084). Among 79 residents in Cohort 2, 60 (75.9%) were identified as MRSA negative at the initial testing. Of these 60 residents, only one (1.7%) had subsequent positive conversion in secondary MRSA testing. In contrast, among 19 residents identified as MRSA positive in the initial testing, 10 (52.6%) were negative in secondary testing.ConclusionsThe prevalence of MRSA was lower among residents with longer periods of LTCF residence than among those with shorter periods. Furthermore, few residents were found to become MRSA carrier after their initial admission. These findings highlight that MRSA in LTCFs might be associated with resident transfer rather than spread via cross-transmission inside LTCFs.

Exposure to Environmental Chemical Mixtures is Associated with Nasal Colonization by Staphylococcus aureus: NHANES 2001-2004

Background: Understanding the health effects of exposure to chemical mixtures is critical given the broad range of concurrent exposures throughout the life-course. While investigations of environmental chemicals and components of the human microbiome are becoming more common, few have examined associations with chemical mixtures. This study assesses the association between exposure to mixtures of 66 different environmental chemicals and nasal colonization of Staphylococcus aureus (SA) and methicillin resistant SA (MRSA).Methods: Data came from the National Health and Nutrition Examination Survey (NHANES) 2001-2004. The analytical sample consists of 10,312 participants, subdivided into 8 different chemical mixture groups. Within each of 6 chemical classes (metals, phthalates, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polyfluorochemicals (PFCs), and phenols), weighted quantile sum (WQS) regression was used to analyze the joint association of the component compounds and nasal SA colonization. WQS was also used to assess the joint association of 3 chemical mixtures (metals, metal and PAHs, and metal and triclosan) and nasal MRSA colonization. All regression models were adjusted for confounders.Results: The analytical sample was between ages 6-85, slightly more female, and predominantly non-smokers. Prevalence of SA carriage was 29.2%, and MRSA colonization prevalence was 1.2%. Within each chemical class, odds of SA colonization increased significantly with exposure to mixtures of metals (OR = 1.11, 95% CI = 1.02-1.20), phthalates (OR = 1.09, 95% CI = 1.04-1.14), and phenols (OR = 1.08, 95% CI = 1.01-1.15). Exposure to a mixture of metals combined with PAHs was also associated with increased odds of MRSA carriage (OR=1.38, 95% CI = 1.02-1.86).Conclusion: Results indicate an association between multiple environmental chemical mixtures and SA colonization, including MRSA. These findings support the need for further analysis of associations between chemical mixtures and SA colonization, as well as other components of the human microbiome.

Colonization and Infection With MRSA and CRKP and Its Result in an Increased Mortality Rate Within the Intensive Care and High-Dependency Units in Barbados

Background: Methicillin-resistant Staphylococcus aureus(MRSA) and carbapenem-resistant Klebsiella pneumoniae (CRKP) are a growing public health concern in Barbados. Intensive care and critically ill patients are at a higher risk for MRSA and CRKP colonization and infection. MRSA and CRKP colonization and infection are associated with a high mortality and morbidly rate in the intensive care units (ICUs) and high-dependency units (HDUs). There is no concrete evidence in the literature regarding MRSA and CRKP colonization and infection in Barbados or the Caribbean. Objectives: We investigated the prevalence of MRSA and CRKP colonization and infection in the patients of the ICU and HDU units at the Queen Elizabeth Hospital from 2013 to 2017. Methods: We conducted a retrospective cohort analysis of patients admitted to the MICU, SICU, and HDU from January 2013 through December 2017. Data were collected as part of the surveillance program instituted by the IPC department. Admissions and weekly swabs for rectal, nasal, groin, and axilla were performed to screen for colonization with MRSA and CRKP. Follow-up was performed for positive cultures from sterile isolates, indicating infection. Positive MRSA and CRKP colonization or infection were identified, and patient notes were collected. Our exclusion criteria included patients with a of stay of &lt;48 hours and patients with MRSA or CRKP before admission. Results: Of 3,641 of persons admitted 2,801 cases fit the study criteria. Overall, 161 (5.3%) were colonized or infected with MRSA alone, 215 (7.67%) were colonized or infected with CRKP alone, and 15 (0.53%) were colonized or infected with both MRSA and CRKP. In addition, 10 (66.6%) of patients colonized or infected with MRSA and CRKP died. Average length of stay of patients who died was 50 days. Conclusions: The results of this study demonstrate that MRSA and CRKP cocolonization and coinfection is associated with high mortality in patients within the ICU and HDU units. Patients admitted to the ICU and HDU with an average length of stay of 50 days are at a higher risk for cocolonization and coinfection with MRSA and CRKP. Stronger IPC measures must be implemented to reduce the spread and occurrence of MRSA and CRKP.Funding: NoneDisclosures: None

Exposure to environmental chemical mixtures is associated with nasal colonization by Staphylococcus aureus: NHANES 2001–2004

BackgroundUnderstanding the health effects of exposure to chemical mixtures is critically important given the broad range of concurrent exposures throughout the life-course. While investigations of environmental chemicals and components of the human microbiome are becoming more common, few have examined associations with chemical mixtures. This study assesses the association between exposure to mixtures of 66 different environmental chemicals and nasal colonization of Staphylococcus aureus (SA) and methicillin resistant SA (MRSA). MethodsData came from the National Health and Nutrition Examination Survey (NHANES) 2001–2004. The analytical sample consists of 10,312 participants, age 6 years and older, subdivided into 8 groups with different chemical exposure mixtures. Within each of 6 chemical classes (metals, phthalates, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polyfluorochemicals (PFCs), and phenols), weighted quantile sum (WQS) regression was used to analyze the joint association of the component compounds and nasal SA colonization. WQS was also used to assess the joint association of 3 chemical mixtures (metals, metal and PAHs, and metal and triclosan) and nasal MRSA colonization. All regression models were adjusted for confounders. ResultsThe analytical sample was between ages 6–85, slightly more female, and predominantly non-smokers. Prevalence of SA carriage was 29.2%, and MRSA colonization prevalence was 1.2%. Within each chemical class, odds of SA colonization increased statistically significantly with exposure to mixtures of metals (OR = 1.11, 95% CI = 1.02–1.20), phthalates (OR = 1.09, 95% CI = 1.04–1.14), and phenols (OR = 1.08, 95% CI = 1.01–1.15). Exposure to a mixture of metals combined with PAHs was also associated with increased odds of MRSA carriage (OR = 1.38, 95% CI = 1.02–1.86). ConclusionResults indicate an association between multiple environmental chemical mixtures and SA colonization, including MRSA. These findings support the need for further analysis of associations between chemical mixtures and SA colonization, as well as other components of the human microbiome.

Nasal colonization with methicillin-resistant Staphylococcus aureus at admission among high-risk Turkish and international patients.

The aim of this study was to detect the frequency of methicillin-resistant Staphylococcus aureus (MRSA) colonization at admission in a group of presumably high-risk international or Turkish patients referred to our center for elective operations, some of whom were from countries with an unknown prevalence of MRSA infection or colonization. The results of nasal swab screening for MRSA colonization performed using a specific algorithm between 2011 and 2018 in a private medical center were retrospectively reviewed. Presence of MRSA was ascertained using culture and/or real-time polymerase chain reaction (real-time PCR). A total of 3,795 patients were included in the study. More than half of the patients were ≤19 years of age (2,094, 55.2%), and MRSA positivity was more common among these patients. Turkish patients constituted 24.5% of the study population. International patients were most frequently referred from Iraq (55.92%), Libya (11.44%), Romania (2.69%), and Bulgaria (1.98%). MRSA positivity was significantly more common among patients referred from other countries when compared to Turkish nationals (11.5% vs. 4.4%, P = 0.00001). Countries with the highest prevalence rates of MRSA colonization were as follows with decreasing order: United Arab Emirates, 25.0%; Georgia, 23.1%; Russia, 22.7%; Iraq, 13.0%, Romania, 12.7%. Other countries with high number of admitted patients (>70 patients) had the following MRSA rates: Turkey, 4.4%; Libya, 6.0%; Bulgaria, 5.3%. Although MRSA has a low prevalence in our center, a variation in the rate of MRSA positivity was observed across patients from different countries. Absence hospital acquired contamination or outbreaks in our institution may be attributed to the screening algorithm used and underscores the importance of risk analysis for patients referred from geographical locations with unknown MRSA frequency, to reduce the risk of transmission.

Methicillin-resistant Staphylococcus aureus colonization in patients undergoing primary total hip arthroplasty.

Introduction. Nasal and skin colonization by methicillin-resistant Staphylococcus aureus (MRSA) are linked to a higher incidence of infection after total joint replacement. The prevalence of colonization is poorly defined in Latin American countries.Aim. The aim of the present study was to determine the prevalence of MRSA colonization in the nostrils and groin using real-time polymerase chain reaction (RT-PCR) in patients undergoing total hip arthroplasty (THA).Methodology. In this cross-sectional study, 146 patients undergoing THA between December 2015 and March 2017 in a tertiary-care university-affiliated hospital in Chile were screened for MRSA colonization before the procedure using RT-PCR independently in the nostrils and groin. Risk factors for colonization were documented.Results. Seven of the 146 (5 %) patients undergoing THA were carriers of MRSA in the nostrils and/or the groin. Recent antibiotic use was identified as a risk factor for colonization, OR=4.86 [95 % confidence interval (CI): 1.56-13.96]. Patients reporting at least one of the seven surveyed risk factors had an OR of 2.39 (95 % CI: 0.37-25.77) for colonization. MRSA colonization frequency was twofold higher in the groin as opposed to the nostrils (P=0.014).Conclusion. Five percent of the patients undergoing THA were identified as carriers of MRSA. Recent antibiotic use is a relevant risk factor for MRSA colonization in patients undergoing primary total hip arthroplasty.

Methicillin-resistant Staphylococcus aureus in veterinary professionals in 2017 in the Czech Republic

BackgroundCases of colonization or infection caused by Methicillin-resistant Staphylococcus aureus (MRSA) are frequently reported in people who work with animals, including veterinary personnel. The aim of this study was to determine the prevalence of MRSA colonization among veterinary professionals. A total of 134 nasal swabs from healthy attendees of a veterinary conference held in the Czech Republic were tested for presence of MRSA. The stains were further genotypically and phenotypically characterized.ResultsNine isolated MRSA strains were characterized with sequence type (ST), spa type (t) and Staphylococcal Cassette Chromosome mec type. Five different genotypes were described, including ST398-t011-IV (n = 5), ST398-t2330-IV (n = 1), ST398-t034-V (n = 1), ST225-t003-II (n = 1) and ST4894-t011-IV (n = 1). The carriage of the animal MRSA strain was confirmed in 8 cases, characteristics of one strain corresponded to the possible nosocomial origin. Among animal strains were described three spa types (t011, t034, t2330) belonging into one dominating clonal complex spa-CC11.ConclusionAccording to our results, the prevalence of nasal carriage of MRSA in veterinary personnel is 6.72%. Although we described an increase compared to the results of previous study (year 2008), the prevalence in the Czech Republic is still remaining lower than reported from neighboring countries. Our results also indicate that healthcare - associated MRSA strains are still not spread among animals.