Methicillin-resistant Staphylococcus Aureus Infection Control Research Articles

Future scope of plant-derived bioactive compounds in the management of methicillin-resistant Staphylococcus aureus: In vitro antimicrobial and antivirulence prospects to combat MRSA

Methicillin-resistant Staphylococcus aureus (MRSA) is a foremost human and animal pathogen with public health and veterinary significance causing hospital and community infections and contagious bovine mastitis. Due to its ability to develop multidrug resistance (MDR) and its pathogenicity, MRSA infection control is becoming a global concern. Natural antibacterial options are needed to combat MDR development and infectious dissemination. This study investigated the antimicrobial resistance and virulence genes profiling of MRSA isolates and explored the antivirulence efficacy of trans-cinnamaldehyde, thymol, and carvacrol essential oils (EOs) against multivirulent and MDR-MRSA isolates. Thirty six S. aureus isolates (25%) were retrieved, of which 34 (94.4%) were MRSA. A high prevalence of MDR (66.7%) was monitored and all 53 molecularly verified isolates possessed icaA and cna virulence genes. Moreover, 94.1% of these isolates were multivirulent with 23.5% of them carrying icaA, cna, eta, tst, and sea virulence genes. Our data proved superior in vitro antimicrobial and antivirulence activities of trans-cinnamaldehyde, thymol, and carvacrol. They inhibited the growth of multi-virulent and MDR-MRSA isolates and downregulated the transcription of examined virulence genes. Our study suggests using EOs as prospective antimicrobials with excellent antivirulence activities against MRSA isolates. We provided data regarding the eventual role of phytogenics in prevention and control of MRSA infection.

Active surveillance and contact precautions for preventing MRSA healthcare-associated infections during the COVID-19 pandemic

Background: Statistically significant decreases in methicillin-resistant Staphylococcus aureus (MRSA) healthcare-associated infections (HAIs) occurred in Veterans Health Administration (VA) facilities from 2007 to 2019 using active surveillance for facility admissions and contact precautions for patients colonized (CPC) or infected (CPI) with MRSA, but the value of these interventions is controversial. Objective: To determine the impact of active surveillance, CPC, and CPI on prevention MRSA HAIs, we conducted a prospective cohort study between July 2020 and June 2022 in all 123 acute-care VA medical facilities. In April 2020, all facilities were given the option to suspend any combination of active surveillance, CPC, or CPI to free up laboratory resources for COVID-19 testing and conserve personal protective equipment. We measured MRSA HAIs (cases per 1,000 patient days) in intensive care units (ICUs) and non-ICUs by the infection control policy. Results: During the analysis period, there were 917,591 admissions, 5,225,174 patient days, and 568 MRSA HAIs. Only 20% of facilities continued all 3 MRSA infection control measures in July 2020, but this rate increased to 57% by June 2022. The MRSA HAI rate for all infection sites in non-ICUs was 0.07 (95% CI, 0.05–0.08) for facilities practicing active surveillance plus CPC plus CPI compared to 0.12 (95% CI, 0.08–0.19; P = .01) for those not practicing any of these strategies, and in ICUs the MRSA HAI rates were 0.20 (95% CI, 0.15–0.26) and 0.65 (95% CI, 0.41–0.98; P < .001) for the respective policies. Similar differences were seen when the analyses were restricted to MRSA bloodstream HAIs. Accounting for monthly COVID-19 admissions to facilities over the analysis period using a negative binomial regression model did not change the relationships between facility policy and MRSA HAI rates in the ICUs or non-ICUs. There was no statistically significant difference in monthly facility urinary catheter-associated infection rates, a nonequivalent dependent variable, in the categories during the analysis period in either ICUs or non-ICUs. Conclusions: In Veterans Affairs medical centers, there were fewer MRSA HAIs when facilities practiced active surveillance and contact precautions for colonized or infected patients during the COVID-19 pandemic. The effect was greater in ICUs than non-ICUs.Disclosures: None

Phenotypic and genotypic profiling reveals a high prevalence of methicillin-resistant Staphylococcus aureus isolated from hospitals, houseflies and adjacent informal food retailers in Botswana.

The increasing occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in the environment, food and healthcare systems is a global public health concern. MRSA is reported to cause food poisoning, osteomyelitis and pyogenic infections of the skin, and consequently has been categorized as a high-priority pathogen by the World Health Organization. Here, we determined the presence of MRSA in clinical (n=56), food (n=150) and housefly samples (n=970) collected from two hospitals in Botswana. Characterization based on phenotypic (antimicrobial resistance, biofilm production) and genotypic (antimicrobial resistance genes and integrons) profiles were performed on all isolates. Of the total samples tested, 64 were positive for MRSA following conventional culture methods and PCR amplification of the mecA and mecC genes for confirmation of presumptive MRSA isolates. The confirmed isolates included 71 % (95 % CI 83.2-59.6) from clinical, 9 % (95 % CI 14--4.8) from food, and 1 % (95 % CI 1.6-0.4) collected from housefly samples. In total 89 % (n=57) isolates in the current study showed a multidrug resistance phenotype, among these, resistance to β-lactams and glycoside antibiotic classes were predominant. Genotypic characterization showed the domination of the blatem gene (95 %) followed by fox (63 %) and tetO (19 %) whilst vanA was only reported in 13 % of the isolates. Integrons were detected in 50 % (32/64) of the total MRSA isolates, and we report a high prevalence of etd gene, detected in 67 % (43/64) of the isolates followed by eta 38 % (24/64) whilst tsst-1 (3%) was the least detected genetic determinant. The genes etb and PVL were not detected in a ll the tested MRSA isolates. We provide the first report on the prevalence of MRSA isolated from the clinical-food-vector nexus harbouring biofilm and blatem genes, and antibiotic resistance profiles in Botswana. These results are significant for risk-assessment analysis and the development of improved MRSA infection prevention and control strategies.

The Dissemination and Molecular Characterization of Clonal Complex 361 (CC361) Methicillin-Resistant Staphylococcus aureus (MRSA) in Kuwait Hospitals.

Methicillin-resistant Staphylococcus aureus (MRSA) belonging to clonal complex 361 (CC361-MRSA) is rare among patients’ populations globally. However, CC361-MRSA has been isolated with an increasing trend among patients in Kuwait hospitals since 2010. This study investigated the molecular characteristics of CC361-MRSA isolated from patients in Kuwait hospitals in 2016–2018 to understand their genetic relatedness and virulence determinants. Of 5,223 MRSA isolates investigated by DNA microarray, 182 (3.4%) isolates obtained in 2016 (N = 55), 2017 (N = 56), and 2018 (N = 71) were identified as CC361-MRSA. The CC361-MRSA isolates were analyzed further using antibiogram, spa typing and multi locus sequence typing (MLST). Most of the isolates were resistant to fusidic acid (64.8%), kanamycin (43.4%), erythromycin (36.3%), and clindamycin (14.3%) encoded by fusC, aphA3, and erm(B)/erm(C) respectively. Nine isolates (4.9%) were resistant to linezolid mediated by cfr. The isolates belonged to 22 spa types with t3841 (N = 113), t315 (N = 16), t1309 (N = 14), and t3175 (N = 5) constituting 81.3% of the spa types, four genotypes (strain types), CC361-MRSA-[V/VT + fus] (N = 112), CC361-MRSA-IV, WA MRSA-29 (N = 36), CC361-MRSA-V, WA MRSA-70/110 (N = 33) and CC361-MRSA-[V + fus] variant (N = 1). MLST conducted on 69 representative isolates yielded two sequence types: ST361 (11/69) and ST672 (58/69). All CC361-MRSA isolates were positive for cap8, agr1, and the enterotoxin egc gene cluster (seg, sei, selm, seln, selo, and selu). The tst1 was detected in 19 isolates. The immune evasion cluster (IEC) genes type B (scn, chp, and sak) and type E (scn and sak) were detected in 20 and 152 isolates, respectively. The CC361-MRSA circulating in Kuwait hospitals consisted of two closely related sequence types, ST361 and ST672 with ST672-MRSA [V/VT + fus] as the dominant genotype. The dissemination of these newly emerged clones and the emergence of linezolid resistance limits therapeutic options, as well as present significant challenges for the control of MRSA infections in Kuwait hospitals.

Eriodictyol as a Potential Candidate Inhibitor of Sortase A Protects Mice From Methicillin-Resistant Staphylococcus aureus-Induced Pneumonia.

New anti-infective approaches are urgently needed to control multidrug-resistant (MDR) pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA). Sortase A (SrtA) is a membrane-bound cysteine transpeptidase that plays an essential role in the catalysis of covalent anchoring of surface proteins to the cell wall of Staphylococcus aureus (S. aureus). The present study reports identification of a flavonoid, eriodictyol, as a reversible inhibitor of SrtA with an IC50 of 2.229 ± 0.014 μg/mL that can be used as an innovative means to counter both resistance and virulence. The data indicated that eriodictyol inhibited the adhesion of the bacteria to fibrinogen and reduced the formation of biofilms and anchoring of staphylococcal protein A (SpA) on the cell wall. The results of fluorescence quenching experiments demonstrated a strong interaction between eriodictyol and SrtA. Subsequent mechanistic studies revealed that eriodictyol binds to SrtA by interacting with R197 amino acid residue. Importantly, eriodictyol reduced the adhesion-dependent invasion of A549 cells by S. aureus and showed a good therapeutic effect in a model of mouse pneumonia induced by S. aureus. Overall, the results indicated that eriodictyol can attenuate MRSA virulence and prevent the development of resistance by inhibiting SrtA, suggesting that eriodictyol may be a promising lead compound for the control of MRSA infections.

855. Significance of Invasive Infections due to Methicillin Sensitive Staphylococcus aureus in the neonatal population

BackgroundStaphylococcus aureus is a well-known cause of hospital acquired infections. Methicillin resistant staphylococcus aureus (MRSA) colonization is a recognized risk factor for invasive infections. The neonatal population in the intensive care unit (NICU) is particularly vulnerable to these types of infections, resulting in high mortality and morbidity. However, only scant data is available to establish the risk for invasive disease in patients with Methicillin sensitive staphylococcus aureus (MSSA). As a result, surveillance and prevention strategies are only address for MRSA colonization. Here, we describe the clinical characteristics of S. aureus colonized patients identified in late 2018 during transmission events in a single center NICU. As a result of the targeted surveillance investigation for MRSA infection control measures, S. aureus colonization was stratified, and we were able to compare the differences in invasive disease between MRSA and MSSA.MethodsThis is a retrospective chart review of the 47 colonized patients identified during October 2018- January 2019 SA transmission events in single center NICU. Risk factors, clinical characteristics, and the hospital course of these cases, including the proportion of invasive illness were reviewed.ResultsWe found that most clinical characteristic, risk factors, and hospital course were the same between MRSA and MSSA colonized infants (p values > 0.05). Additionally, there was no difference in the proportion of invasive infection between MRSA and MSSA colonized patients (p value > 0.05). The type of invasive infections identified were SSTI, bacteremia, and osteomyelitis.ConclusionThe proportion of invasive infection was the same in MSSA and MRSA colonized patients. This data provides us with supportive material for future recommendations of infection control measures for MSSA colonized patients.Disclosures All Authors: No reported disclosures

Formulation and evaluation of anti-MRSA nanoemulsion loaded with Achyrocline satureioides: a new sustainable strategy for the bovine mastitis

Methicillin-resistant Staphylococcus aureus (MRSA) causes mastitis in dairy cattle with serious economic and public health significance. This study developed nanoemulsions of Linum usitatissimun oil loaded with Achyrocline satureioides (macela) extract and investigated their in vitro antimicrobial activity against MRSA. Macela-nanoemulsions (NE-ML) were prepared using high-pressure homogenization (HPH) with different proportions of flaxseed oil, Tween 80 and crude extract. Four majoritarian flavonoids were identified in the macela extract: 3-O methylquercetin, achyrobichalcone, quercetin and luteolin (187.3 ± 0.1, 155.4 ± 11.6, 76.3 ± 0.1 and 30.4 ± 0.0 μg ml−1, respectively). NE-ML nanoemulsions were successfully obtained by the HPH method and showed a milky aspect with yellowish color. The mean particle size was around 200 nm with monodisperse distribution (PdI < 0.2), remaining stable for 160 days at room temperature. When analyzed on a LUMiSizer high-end dispersion analyzer, low values were found (≤0.5), indicating high stability index, mainly for NE-ML1:5 (0.2). The encapsulation efficiency of macela-nanoemulsions was greater than 94%, considering the four chemical compounds from extract. Minimum inhibitory concentration (MIC) against planktonic bacteria, inhibition of biofilm formation (MBIC), and eradication of MRSA biofilms (MBEC) were determined through in vitro tests on microplates. The MIC of NE-ML against planktonic MRSA showed values ranging from 1.2 to 10% (v/v), while blank-nanoemulsions (NE-B, without macela extract) showed values ranging from 6 to 50% (v/v). MBIC and MBEC of NE-ML were 25 and 80% (v/v), respectively. MBIC showed a mass reduction greater than 64%, and MBEC showed a mass reduction greater than 73%. Macela-nanoemulsions (NE-ML), mainly NE-ML1:5, showed high antimicrobial activity and appeared to represent a new alternative of sustainable antimicrobial product for the control of MRSA. Since this innovative nanoemulsion can impact animal health, future research should include in vitro and in vivo studies to evaluate intramammary therapy and control of MRSA infections in organic and agroecological milk production systems.

The effect of isolation precautions on care processes and medical outcomes in patients colonized with MRSA.

Background: Isolation precautions used in methicillin-resistant Staphylococcus aureus (MRSA) infection control are effective in inhibiting pathogen transmission, but may cause unintended consequences in medical care. In addition, while costs attributed to MRSA are known to be substantial, little is known about their reimbursement in the German Diagnosis Related Groups (G-DRG) payment system. The aim of our study was to examine the effect of isolation precautions used in MRSA infection control on care processes, patient outcomes and deliver reliable data on MRSA-attributed reimbursement.Methods: A retrospective, matched cohort study of inpatients admitted to a general care teaching hospital in Bad Neuenahr, Germany, between January 1st, 2016, and December 31st, 2017 was performed. Patients isolated for MRSA colonization were matched to non-isolated controls based on age, gender, MRSA-adjusted Patient Clinical Complexity Level (Ma-PCCL) and Major Diagnostic Category (MDC). Main outcome measures on care processes and patient outcomes included adverse events, patient complaints, 30-day readmission rates, length of stay, type of discharge, and performance of instrument-based diagnostics. MRSA-attributed reimbursement was measured by conducting two separate G-DRG groupings, one with inclusion of MRSA-related codes and one without. Results: A total of 26,059 patients were admitted to Maria Hilf Hospital in Bad Neuenahr, Germany, during the study period. We identified 304 patients isolated for MRSA colonization. Compared to non-isolated matched controls, those on isolation precautions for MRSA colonization acquired about 45% more pressure ulcers and experienced significant delays in the performance of radiological diagnostics and echocardiographs. Patients isolated for MRSA colonization received about 49% fewer echocardiographs and had about 38% fewer abdominal ultrasound exams performed compared to non-isolated matched controls. A non-significant tendency towards fewer discharges to rehabilitation clinics and higher mortality rates were observed in patients isolated for MRSA colonization. Reimbursements were negligibly affected when MRSA-related codes were integrated by the grouper.Conclusion: Isolation precautions are associated with adverse consequences for care processes. These consequences need to be mitigated in order to justify placing patients at risk.

Knowledge, attitudes and practices regarding methicillin-resistant Staphylococcus aureus (MRSA) infection control and nasal MRSA carriage rate among dental health-care professionals

Dental health-care professionals (DHCPs) with nasal colonisation of methicillin-resistant Staphylococcus aureus (MRSA) can serve as a reservoir for MRSA transmission to others and be exposed to self-contamination with MRSA. Evaluating the knowledge, attitudes and actual practice of DHCPs is imperative for appropriate infection control. Dentists, dental hygienists and dental technologists from Seoul National University Dental Hospital were recruited to participate in a cross-sectional survey and undergo nasal sampling of MRSA. The survey included demographic questions, six questions about knowledge, eight questions about attitudes/perceptions and six questions about practices/behaviours regarding MRSA infection control. Nasal samples from the participants were analysed for MRSA presence, antimicrobial susceptibility and staphylococcal cassette chromosome mec (SCCmec) typing. MRSA carriers underwent decolonisation with topical mupirocin. Among 139 DHCPs, four (2.9%) were nasal MRSA carriers. Decolonisation was successful in three participants. One participant was decolonised with topical fusidic acid after failure to decolonise with mupirocin. Dentists had a higher knowledge score compared with the other professionals (P < 0.05). Dental hygienists scored higher on practice questions compared with the other professionals (P < 0.05). There was a significant, positive correlation between attitude and practice scores (P < 0.01). The nasal MRSA carriage rate among DHCPs is 2.9%, which is higher than that in the general population but lower than that in other health-care professionals. Further education of DHCPs on MRSA, especially regarding its seriousness, is needed to improve MRSA infection control in a dental hospital setting.

Emerging variants of methicillin-resistant Staphylococcus aureus genotypes in Kuwait hospitals.

BackgroundFrequent changes in the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) occurring worldwide demand regular surveillance to study their composition and distribution in healthcare facilities. We investigated the genotypic characteristics of MRSA obtained in Kuwait hospitals to better understand their clonal distribution.Materials and methodsA total of 1,327 MRSA isolates obtained from clinical samples in 13 Kuwait hospitals from 1 January to 31 December 2016 were investigated using antibiogram, SCCmec typing, spa typing and DNA microarray.ResultsThe isolates belonged to six SCCmec types with the majority belonging to type IV (658; 49.5%) and type V (355; 26.7%). Two hundred and sixty-one spa types were identified with spa types t688, t304, t860, t127, t044, t311, t002, t223, t267, t019, t3841, t005, t084, t852, and t657 constituting 51.0% (n = 677) of the isolates. Among the 1,327 MRSA isolates, 102 (7.68%) isolates were identified as novel variants of internationally recognized MRSA clones. These 102 isolates were investigated further and belonged to 14 clonal complexes (CCs) with CC361 (32; 32.3%), CC30 (15; 14.7%), CC22 (13; 12.7%) and CC1 (11, 10.7%) as the dominant CCs. Eighty-one (79.4%) of the novel isolates harbored SCCmec IV or V+fusC composite genetic elements. Four isolates (3.9%) harbored unusual combinations of ccr and mec complexes comprising of CC6-MRSA [IV+fusC+ccrC], CC97-MRSA [V/VT+fusC+ccrAB2], CC121-MRSA [V/VT+fusC+ccrB4] and CC1-MRSA-pseudoSCCmec [class B mec+fusc+ccrAB1]. Forty-six (45.1%) of these isolates were positive for PVL and 89 (87.2%) were resistant to fusidic acid mediated by fusC.ConclusionsThe study showed the emergence of novel variants of previously recognized MRSA genotypes with unusual genetic characteristics including high prevalence of PVL and fusidic acid resistance in Kuwait hospitals. This has added to the dynamic lists of known variations in MRSA genomes which can impose serious challenges for infection control and treatment of MRSA infections.

A multicenter study of targeted surveillance at Intensive Care Unit acquired MRSA infection in Tianjin district

Objective To study the incidence and risk factors of infection caused by methicillin-resistant staphylococcus aureus(MRSA)with a targeted surveillance at intensive care unit(ICU)acquired MRSA infection in Tianjin area. Methods A prospective multi-center observational analysis of consecutive patients admitted to 15 adult ICUs from March 1, 2012 through March 31, 2014 was carried out. The ICUs were divided into four groups according to the type of the ICU. All of the patients were cared for with routine MRSA surveillance. A number of risk markers and prognostic factors were recorded. The risk factors contributing to ICU acquired MRSA were evaluated using a logistic regression model. Comparison of survival between groups was analyzed with Kaplan-Meier method. Results A total of 1 787 patients were enrolled, and 144 cases of them were MRSA infections. The patients with MRSA infection were significantly older than those with non-MRSA infection (P=0.043), length of ICU stay, length of antimicrobial therapy, the history of repeated administration of antibiotics in recent days, history of operation in the past five years, history of MRSA infection or colonization, frequent application of and the overall length of time for mechanical ventilation and central venous catheter and catheter-associated infection were significantly higher than those with non-MRSA infection. The survival rate of patients with non-MRSA infection were higher than those with MRSA infection (χ2=9.23, P=0.004). The rate of MRSA infection and MRSA colonization in 2013 were significantly lower than that in 2012, because the rate of hand hygiene rule execution and bacterial clearance rate were significantly higher in 2013. Multivariate Logistic regression analysis demonstrated that advanced age (OR=1.05, 95%CI: 1.009-1.086), length of ICU stay (OR=1.05, 95%CI: 1.01-1.08), history of MRSA infection or colonization(OR=1.33, 95%CI: 1.82-3.27), glucocorticoid therapy(OR=2.85, 95%CI: 1.18-6.91), antacid medicine(OR=4.92, 95%CI: 1.18-20.58), history of recent or repeated application of antibiotics(OR=3.26, 95%CI: 1.06-4.59)catheter-associated infections (OR=2.22, 95%CI: 1.08-4.59) were associated with ICU acquired MRSA infections. Conclusions Performing the rule of hand hygiene strictly as well as strengthening prevention and control of MRSA infections can effectively reduce the incidence of ICU acquired MRSA infections. The advanced age, length of ICU stay, history of MRSA infection or colonization, glucocorticoid therapy, antacids medicine, history of recent or repeated application of antibiotics, catheter-associated infections were independent risk factors of ICU acquired MRSA infections. Key words: Intensive care unit; Methicillin resistant staphylococcus aureus(MRSA); Risk factor; Targeted surveillance

Using Positive Deviance in the prevention and control of MRSA infections in a Colombian hospital: a time-series analysis.

Positive Deviance (PD) is a process to achieve a social and cultural change. This strategy has been used for the control of methicillin-resistant Staphylococcus aureus (MRSA) infection in some health institutions in the United States, but has rarely been adopted in institutions from developing countries where resources are limited. We describe our experience of PD in the control of healthcare-associated infections (HAIs) due to MRSA in a Colombian hospital with the aim of reducing HAI rates through a cultural change in processes. A time-series study was conducted based on the MRSA-HAI rate and the number of months with zero MRSA infections before and after application of PD (2001-2012). On comparing the pre-intervention and intervention periods, the mean overall rates of MRSA-HAI was 0·62 and 0·36, respectively (P = 0·0005); the number of months with zero MRSA-HAIs were 3/70 and 12/74 (odds ratio 0·264, 95% confidence interval 0·078-0·897); the percentage of MRSA-HAIs was 53·2% and 41·0%. These results are consistent with other published data. Implementation of PD was associated with a significant reduction of MRSA-HAIs, it did not involve high costs and the changes have been lasting.

Methicillin-Resistant Staphylococcus aureus Nasal Colonization in Chinese Children: A Prevalence Meta-Analysis and Review of Influencing Factors.

ObjectiveTo determine the pooled prevalence and review the influencing factors of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization in Chinese children.MethodsArticles published between January 2005 and October 2015 that studied prevalence or influencing factors of MRSA nasal colonization in Chinese children were retrieved from Chinese Biomedical Literature database (CBM), China National Knowledge Infrastructure (CNKI) database, Chinese VIP database, Chinese Wanfang database, Medline database and Ovid database. Prevalence and influencing factors were analyzed by STATA 13.1.ResultsThirteen articles were included. The overall prevalence of MRSA nasal colonization was 4.4% (95% confidence interval [CI]: 0.027–0.062). With an MRSA prevalence of 3.9% (95% CI: 0.018–0.061) in healthy children and 5.8% (95% CI: 0.025–0.092) in children with underlying medical conditions. Children recruited in the hospitals presented MRSA prevalence of 6.4% (95% CI: 0.037–0.091), which was higher than those recruited in the communities [2.7% (95% CI: 0.012–0.043)]. A number of influencing factors for MRSA nasal colonization were noted in three eligible studies: gender (male vs female; OR: 0.67; 95% CI: 0.55–0.82), younger age (OR: 2.98; 95% CI: 1.31–6.96 and OR: 1.56; 95% CI: 1.21–2.00), attending day care centers (OR: 2.97; 95% CI: 1.28–6.76), having infectious diseases (OR: 2.31; 95% CI: 1.10–4.52), using antibiotics (OR: 2.77; 95% CI: 1.45–5.05), residing in northern Taiwan (OR: 1.41; 95% CI: 1.15–1.71), passive smoking (OR: 1.30; 95% CI: 1.02–1.63), and pneumococcal vaccination (OR: 1.22; 95% CI: 1.01–1.48).ConclusionsChildren could act as reservoirs of MRSA transmissions. Hospitals remained the most frequent microorganism-circulated settings. More MRSA infection control strategies are required to prevent the dissemination among children.

Evidence for Community Transmission of Community-Associated but Not Health-Care-Associated Methicillin-Resistant Staphylococcus Aureus Strains Linked to Social and Material Deprivation: Spatial Analysis of Cross-sectional Data.

BackgroundIdentifying and tackling the social determinants of infectious diseases has become a public health priority following the recognition that individuals with lower socioeconomic status are disproportionately affected by infectious diseases. In many parts of the world, epidemiologically and genotypically defined community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged to become frequent causes of hospital infection. The aim of this study was to use spatial models with adjustment for area-level hospital attendance to determine the transmission niche of genotypically defined CA- and health-care-associated (HA)-MRSA strains across a diverse region of South East London and to explore a potential link between MRSA carriage and markers of social and material deprivation.Methods and FindingsThis study involved spatial analysis of cross-sectional data linked with all MRSA isolates identified by three National Health Service (NHS) microbiology laboratories between 1 November 2011 and 29 February 2012. The cohort of hospital-based NHS microbiology diagnostic services serves 867,254 usual residents in the Lambeth, Southwark, and Lewisham boroughs in South East London, United Kingdom (UK). Isolates were classified as HA- or CA-MRSA based on whole genome sequencing. All MRSA cases identified over 4 mo within the three-borough catchment area (n = 471) were mapped to small geographies and linked to area-level aggregated socioeconomic and demographic data. Disease mapping and ecological regression models were used to infer the most likely transmission niches for each MRSA genetic classification and to describe the spatial epidemiology of MRSA in relation to social determinants. Specifically, we aimed to identify demographic and socioeconomic population traits that explain cross-area extra variation in HA- and CA-MRSA relative risks following adjustment for hospital attendance data. We explored the potential for associations with the English Indices of Deprivation 2010 (including the Index of Multiple Deprivation and several deprivation domains and subdomains) and the 2011 England and Wales census demographic and socioeconomic indicators (including numbers of households by deprivation dimension) and indicators of population health. Both CA-and HA-MRSA were associated with household deprivation (CA-MRSA relative risk [RR]: 1.72 [1.03–2.94]; HA-MRSA RR: 1.57 [1.06–2.33]), which was correlated with hospital attendance (Pearson correlation coefficient [PCC] = 0.76). HA-MRSA was also associated with poor health (RR: 1.10 [1.01–1.19]) and residence in communal care homes (RR: 1.24 [1.12–1.37]), whereas CA-MRSA was linked with household overcrowding (RR: 1.58 [1.04–2.41]) and wider barriers, which represent a combined score for household overcrowding, low income, and homelessness (RR: 1.76 [1.16–2.70]). CA-MRSA was also associated with recent immigration to the UK (RR: 1.77 [1.19–2.66]). For the area-level variation in RR for CA-MRSA, 28.67% was attributable to the spatial arrangement of target geographies, compared with only 0.09% for HA-MRSA. An advantage to our study is that it provided a representative sample of usual residents receiving care in the catchment areas. A limitation is that relationships apparent in aggregated data analyses cannot be assumed to operate at the individual level.ConclusionsThere was no evidence of community transmission of HA-MRSA strains, implying that HA-MRSA cases identified in the community originate from the hospital reservoir and are maintained by frequent attendance at health care facilities. In contrast, there was a high risk of CA-MRSA in deprived areas linked with overcrowding, homelessness, low income, and recent immigration to the UK, which was not explainable by health care exposure. Furthermore, areas adjacent to these deprived areas were themselves at greater risk of CA-MRSA, indicating community transmission of CA-MRSA. This ongoing community transmission could lead to CA-MRSA becoming the dominant strain types carried by patients admitted to hospital, particularly if successful hospital-based MRSA infection control programmes are maintained. These results suggest that community infection control programmes targeting transmission of CA-MRSA will be required to control MRSA in both the community and hospital. These epidemiological changes will also have implications for effectiveness of risk-factor-based hospital admission MRSA screening programmes.

Impact of different diagnostic technologies for MRSA admission screening in hospitals - a decision tree analysis.

BackgroundHospital infections with multiresistant bacteria, e.g., Methicillin-resistant Staphylococcus aureus (MRSA), cause heavy financial burden worldwide. Rapid and precise identification of MRSA carriage in combination with targeted hygienic management are proven to be effective but incur relevant extra costs. Therefore, health care providers have to decide which MRSA screening strategy and which diagnostic technology should be applied according to economic criteria.AimThe aim of this study was to determine which MRSA admission screening and infection control management strategy causes the lowest expected cost for a hospital. Focus was set on the Point-of-Care Testing (PoC).MethodsA decision tree analytic cost model was developed, primarily based on data from peer-reviewed literature. In addition, univariate sensitivity analyses of the different input parameters were conducted to study the robustness of the results.FindingsIn the basic analysis, risk-based PoC screening showed the highest mean cost savings with 14.98 € per admission in comparison to no screening. Rapid universal screening methods became favorable at high MRSA prevalence, while in situations with low MRSA transmission rates omission of screening may be favorable.ConclusionEarly detection of MRSA by rapid PoC or PCR technologies and consistent implementation of appropriate hygienic measures lead to high economic efficiency of MRSA management. Whether general or targeted screening is more efficient depends mainly on epidemiological and infrastructural parameters.

Antibacterial activity of honey from stingless bees Scaptotrigona bipunctata Lepeletier, 1836 and S. postica Latreille, 1807 (Hymenoptera: Apidae: Meliponinae) against methicillin-resistant Staphylococcus aureus (MRSA)

The antibacterial activity of honey produced by the stingless bees Scaptotrigona postica (H6) and Scaptotrigona bipunctata (H7) was evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains. Fifty-three MRSA strains in the bacterial collection of the hospital of Londrina State University, three standard MRSA strains and two standard MSSA strains were used. Evaluation of the antibacterial activity of honey samples was determined by agar well diffusion assay, calculation of minimum inhibitory concentrations (MICs), and construction of growth and viability curves. The inhibition zones generated by the honey samples ranged from 20 to 27 mm for H6 and 20 to 24 mm for H7, while MIC values ranged from 0.62 to 1.25% for H6 and 1.25 to 2.5% for H7. According to the growth curves, the growth of all MRSA and MSSA strains was completely inhibited. Honey cytotoxicity was evaluated by dimethylthiazol diphenyl tetrazolium bromide (MTT) assay, and the CC50 values were found to be 13% for H6 and 7.3% for H7, which were significantly higher when compared to the MIC values. The honey of both the stingless bees S. bipunctata and S. postica can thus be utilized as antibacterial substances against MSSA and MRSA strains, and this action is probably due to a synergistic action of different components such as hydrogen peroxide, sugars, and other compounds not identified in this study. The application of natural products is important for the control of MRSA infections. Further studies are warranted to demonstrate that the antimicrobial activity of the honey examined here could be used in clinical applications for the prevention of MRSA infections.

The Factors Influencing Compliance of Multidrug-resistant Organism Infection Control in Intensive Care Units Nurses

Purpose: This study was conducted to identify factors influencing compliance of multidrug-resistant organism infection control in intensive care units (ICU) nurses. Methods: Data were collected from 254 ICU nurses who were working at 6 general and advanced general hospitals in D city and G Province. Results: 77.2% and 84.4% of the subjects correctly answered to questions about Methicillin-Resistant Staphylococcus Aureus (MRSA) and VancomycinResistant Enterococcus (VRE), respectively. The scores of MRSA infection control compliance and VRE infection control compliance were 3.41 and 3.43, respectively. The factors influencing MRSA infection control compliance were empowerment, environmental safety recognition, and education satisfaction, which explained 30% of MRSA infection control compliance. The factors significantly related to VRE infection control compliance were empowerment, hospital types, environmental safety recognition, number of education sessions, and neonatal ICU, which explained 37% of VRE infection control compliance. Conclusion: It is necessary to develop efficient educational programs for infection control including educational contents to improve empowerment and environmental safety recognition of nurses. Furthermore, administrative support for those infection control programs is also necessary.

Screening for methicillin-resistant Staphylococcus aureus … all doors closed?

To describe the latest evidence for methicillin-resistant Staphylococcus aureus (MRSA) infection control strategies, with particular emphasis on active surveillance cultures with contact precautions and targeted decolonization, and their impact. Several major trials published last year questioned the effectiveness of universal screening and contact precautions in controlling MRSA. These trials generally recommend universal decolonization as part of bundles to control MRSA, especially in ICUs, with some even concluding that universal decolonization should replace active screening and contact precautions. However, emerging resistance to agents used for decolonization, such as mupirocin and chlorhexidine, is a major concern. Several other studies confirmed a combination of hand hygiene enhancement, screening, contact precaution and targeted decolonization as a more viable MRSA infection control strategy for specific population groups. Universal decolonization is an acceptable MRSA control strategy for intensive care units; however, close monitoring of chlorhexidine and mupirocin resistance is warranted. As a strategy, screening and contact precautions are suitable for hospital-wide MRSA control. Targeted decolonization is a proven measure for patients undergoing clean surgery. Enhancement of hand hygiene is a core measure regardless of the strategy.

Prevalence of Methicillin-Resistant Staphylococcus aureus (MRSA) in Raw Meat and Meat Handlers in Onitsha, Nigeria

Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen, causing severe morbidity and mortality worldwide both in hospitals and the community. Recent reports of isolation of methicillin-resistant Staphylococcus aureus (MRSA) from food animals, their meats as well as animal keepers have raised concern about the potential for food borne and zoonotic transmission. This study, evaluated the prevalence of MRSA in meat and meat handlers in Onitsha, Nigeria. A total of 274 samples were collected and analyzed using standard microbiological techniques. Staphylococcus aureus isolates were properly identified using standard procedures and confirmed as methicillin-resistant Staphylococcus aureus using Oxacillin-Resistance Screening Agar Base (ORSAB), supplemented with 2 g/l oxacillin. MRSA prevalence rates of 11(14.3%), 6(85.7%), 4(57.1%) and 12(63.2%) were observed in Beef, Pork, Donkey and Goat meats respectively. There was a significant difference in MRSA prevalence among the meat types (X2= 107.936; P<0.05). The Butchers’ tables showed MRSA prevalence of 3(50%), 8(100%), 2(100%) and 4(100%) for Beef, Goat, Pork and Donkey respectively, while the recovery rates of the organism from cutting knives were 2(33.33%), 7(100%), 2(100%) and 4(100%) for Beef, Goat, Pork and Donkey respectively; no MRSA was recovered from carcass dressing water. Out of 5 MRSA isolates from the body of live cows, 1(20%) was from the nostril, 2(40%) from the ear and 2(40%) from the groin. Over-all, the occurrence of MRSA in butchers was 51%. Out of 29 MRSA isolates from butchers, 12(41.38%) were from butchers 1-10 years in business, 9(31.03%) from 11-20 years, 5(17.24%) from 21-30 years. Two (6.9%) were observed in butchers 31-40 years in business, while 1(3.44%) was from 41-50 years in business. The high prevalence of MRSA in meat and its handlers tends to be of public health concern as it may play a potential role in disseminating the organism between animals and humans as well as to the community. Therefore, proper hygienic practices, control of indiscriminate use of antibiotics, and frequent screening of the risk population for MRSA, are hereby recommended both for prevention and control of meat borne infections and other community-acquired MRSA infections.

Methicillin-Resistant Staphylococcus Aureus (MRSA) among Patients seen at a Tertiary Hospital in Maiduguri, Nigeria

Methicillin-resistant Staphylococcus aureus (MRSA) is the major causative bacterial pathogen responsible for hospital and community associated i nfections. Active surveillance remains the key component of MRSA infection control in the hospital setting. This study examined the MRSA colonization level among patients seen at the tertia ry hospital. The study was conducted at University of Maiduguri Teaching Hospital, Nigeria. A standardized questionnaire and interview was employed in enrolling 231 patients into the study a nd 3 anatomical body sites (nasal, axilla and groin) per patient were swabbed and analysed by sta ndard bacteriological techniques. A total of 981 specimens were analysed, 21(2.1%) S.aureus isolates were identified, 10(%) MRSA and 11(%) MSSA isolates detected. The mean age was 34.02+13.2 year s, gender distribution of 12(57.1%) male and 9(42.9%) female. Majority of S.aureus isolates were recovered from nasal compared to non-nasal origin (<0.001), while no statistical significant d ifference was observed between the MRSA colonization and demographic variable documented. Th e S.aureus isolates demonstrated high resistant pattern to fusidic acid, all MRSA isolate s exhibited multidrug resistant pattern and inducib le phenotype. This is the first report on MRSA coloni zation level among patients management in a hospital setting in this geographical zone, and the S.aureus strains demonstrated high resistant to fusidic acid and exhibited high inducible phenotype which is of public health concern particularly i n infection control and patient management.