Project description:The global spread of methicillin-resistant Staphylococcus aureus (MRSA) is a serious problem, particularly in mainland China. In order to better understand the national molecular epidemiology and resistance profiles of hospital-associated MRSA (HA-MRSA) in China, a laboratory-based multicenter surveillance study was conducted. Sixty-nine hospitals in 45 large cities in 27 provinces were involved, and a total of 1,141 HA-MRSA isolates were collected during the 6-month study period in 2011. All MRSA isolates were characterized by multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, spa typing, detection of the Panton-Valentine leukocidin (PVL) locus (lukS-PV and lukF-PV), and antibiogram analysis. ST239-III-t030, ST239-III-t037, and ST5-II-t002 were the predominant HA-MRSA clones (overall prevalence rates, 57.1%, 12.9%, and 8.1%, respectively), although the prevalence rates of these major clones varied markedly in different administrative regions. Of note, 6.6% of the HA-MRSA isolates were found to belong to ST59, which had typical community-associated MRSA (CA-MRSA) features, including carriage of SCCmec type IV or V and PVL and less antimicrobial resistance than other major HA-MRSA clones. Moreover, among 36 MLST sequence types (STs) identified, 15 STs, accounting for 3.5% of total isolates, were novel. A novel ST designated ST2590, which is a single-locus variant of ST5-II-t002, was identified in three hospitals in two large cities, with a total of 17 isolates. To further monitor trends in HA-MRSA prevalence, epidemic clonal shifts, clone emergence, and transmission between community and health care settings, longitudinal national MRSA surveillance is required.
Project description:The report of methicillin-resistant Staphylococcus aureus (MRSA) encoding a divergent mecA gene in 2011 was highly significant. This homologue, designated mecC, poses diagnostic problems with the potential to be misdiagnosed as methicillin-sensitive S. aureus, with important potential consequences for individual patients and for the surveillance of MRSA. mecC MRSA have now been reported from 13 European countries and have been isolated from 14 different host species, with evidence of a recent increase in Denmark. The emergence of mecC MRSA is a topic of interest to human and veterinary microbiology, and we consider it timely to review here its discovery and subsequent investigation.
Project description:Methicillin-resistant Staphylococcus aureus (MRSA) infections are a serious global problem, with considerable impact on patients and substantial health care costs. This systematic review provides an overview on the clonal diversity of MRSA, as well as the prevalence of Panton-Valentine leukocidin (PVL)-positive MRSA in Africa. A search on the molecular characterization of MRSA in Africa was conducted by two authors using predefined terms. We screened for articles published in English and French through to October 2014 from five electronic databases. A total of 57 eligible studies were identified. Thirty-four reports from 15 countries provided adequate genotyping data. CC5 is the predominant clonal complex in the healthcare setting in Africa. The hospital-associated MRSA ST239/ST241-III [3A] was identified in nine African countries. This clone was also described with SCCmec type IV [2B] in Algeria and Nigeria, and type V [5C] in Niger. In Africa, the European ST80-IV [2B] clone was limited to Algeria, Egypt and Tunisia. The clonal types ST22-IV [2B], ST36-II [2A], and ST612-IV [2B] were only reported in South Africa. No clear distinctions were observed between MRSA responsible for hospital and community infections. The community clones ST8-IV [2B] and ST88-IV [2B] were reported both in the hospital and community settings in Angola, Cameroon, Gabon, Ghana, Madagascar, Nigeria, and São Tomé and Príncipe. The proportion of PVL-positive MRSA carriage and/or infections ranged from 0.3 to 100% in humans. A number of pandemic clones were identified in Africa. Moreover, some MRSA clones are limited to specific countries or regions. We strongly advocate for more surveillance studies on MRSA in Africa.
Project description:Background: Policies to reduce methicillin-resistant Staphylococcus aureus (MRSA) infections, both healthcare-acquired (HA-MRSA) and livestock-associated (LA-MRSA) are implemented Europe-wide, but evaluations are difficult for countries yet to implement such policies. A descriptive study was conducted, describing multinational MRSA rates and policy implementation, focusing on MRSA mandatory surveillance. We also investigated antibiotic use and MRSA rates and the use of veterinary antibiotics. Methods: This study used Europe-wide surveillance data on infectious diseases (EARS-Net), antibiotic consumption (ESAC-Net), and veterinary medicine (ESVAC). We visualized LA- and HA-MRSA related policies and MRSA rates from 1999 to 2015 in seven European countries. Changes in MRSA rates after implementation of an MRSA mandatory surveillance policy were investigated by setting each country as rate of 1.0 and compared countries with and without such policy. Correlations between antibiotic use and MRSA rates from 1999 to 2012 were investigated using defined daily dose. Sales data were used to investigate veterinary antibiotic use. Results: MRSA rates were 1-45.4% across the seven countries between 1999 and 2015. MRSA rates changed between 0.61 and 0.24 after the implementation of mandatory surveillance policies within a 6-12 year span. The rate of decrease rate in implemented and non-implemented countries ranged from 10% in Spain to 76% in the UK. The correlation between MRSA rate and cephalosporin consumption was r = 0.419, and for fluoroquinolones r = 0.305. Mean annual sales of veterinary cephalosporin and quinolone antibiotics were lowest in the UK (0.8 mg/PCU) and highest in Spain (9.7 mg/PCU) between 2009 and 2014. Conclusions: There were similar but different health policy implications in the seven countries regarding LA- and HA-MRSA. Although causation could not be defined, some policies such as mandatory surveillance may be helpful for countries that have yet to implement an MRSA policy. Further investigations are needed to evaluate each policies.
Project description:Whole-genome sequencing (WGS) of methicillin-resistant Staphylococcus aureus (MRSA) has been sparse in low- and middle-income countries, therefore, its population structure is unknown for many regions. We conducted a pilot surveillance of MRSA in the maternity ward of a teaching hospital in Armenia, to characterize the genotypes of circulating MRSA clones. In total, 10 MRSA isolates from a hospital environment (n = 4) and patients (n = 6) were recovered between March and May 2015 and April and May 2016, respectively. WGS analysis showed that the isolates belonged to two clonal complexes (CCs): CC8 (n = 8) and CC30 (n = 2). MRSA CC30 isolates carried staphylococcal cassette chromosome mec (SCCmec) type IVa, whereas MRSA CC8 revealed a type-VT-related SCCmec, which contained a CRISPR/Cas array and showed a high similarity to SCCmec found in coagulase-negative staphylococci. All but one MRSA CC8 isolates carried a plasmid identical to the pSK67 and four also carried a pathogenicity island similar to SaPI5. Phylogenetic analysis showed that the MRSA CC8 isolates formed a monophyletic cluster, which emerged around 1995 and was distinct from representatives of globally-distributed MRSA CC8 lineages. WGS characterization of MRSA in countries with no previous S. aureus genomic surveillance can therefore reveal an unrecognized diversity of MRSA lineages.
Project description:Control of nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) has been unsuccessful in most countries. Yet, some countries have maintained low endemic levels by implementing nationwide MRSA-specific infection control measures, such as "search & destroy" (S&D). These strategies, however, are not based on well designed studies, and their use in countries with high levels of endemicity is controversial. We present a stochastic three-hospital model and an analytical one-hospital model to quantify the effectiveness of different infection control measures and to predict the effects of rapid diagnostic testing (RDT) on isolation needs. Isolation of MRSA carriers identified by clinical cultures is insufficient to control MRSA. However, combined with proactive search (of high-risk patients on admission and/or contacts of index patients), it will maintain prevalence levels <1%. Concerted implementation of S&D in countries with high nosocomial endemicity reduces nosocomial prevalence to <1% within 6 years. Stepwise implementation of control measures can reduce isolation capacities needed. RDT can reduce isolation needs by >90% in low-endemic settings and by 20% in high-endemic settings. Surveillance of colonization and improved hand hygiene can markedly increase control efficacy. These findings strongly suggest that: (i) causality exists between S&D and low MRSA prevalence; (ii) isolating MRSA carriers identified by clinical cultures as a single measure is insufficient for control; (iii) a combined approach of isolation and screening confers efficacy; and (iv) MRSA-prevalence levels can be reduced to <1% in high-endemic settings by S&D or a stepwise approach to interventions. RDT can markedly enhance feasibility.
Project description:The Agency for Healthcare Research & Quality (AHRQ) found that Methicillin-resistant Staphylococcus aureus (MRSA) is associated with up to 375,000 infections and 23,000 deaths in the United States. It is a major cause of surgical site infections, with a higher mortality and longer duration of care than Methicillin-sensitive Staphylococcus aureus. A multifactorial bundled approach is needed to control this epidemic, with single interventions unlikely to have a significant impact on attenuating MRSA infection rates. Active surveillance has been studied in a wide range of surgical patients, including surgical intensive care and non-intensive care units; cardiac, vascular, orthopedic, obstetric, head and neck cancer and gastrostomy patients. There is sufficient evidence demonstrating a beneficial effect of surveillance and eradication prior to surgery to recommend its use on an expanded basis. Studies on MRSA surveillance in surgical patients that were published over the last 10 years were reviewed. In at least five of these studies, the MRSA colonization status of patients was reported to be a factor in preoperative antibiotic selection, with the modification of treatment regiments including the switching to vancomycin or teicoplanin in MRSA positive preoperative patients. Several authors also used decolonization protocols on all preoperative patients but used surveillance to determine the duration of the decolonization. Universal decolonization of all patients, regardless of MRSA status has been advocated as an alternative prevention protocol in which surveillance is not utilized. Concern exists regarding antimicrobial stewardship. The daily and universal use of intranasal antibiotics and/or antiseptic washes may encourage the promotion of bacterial resistance and provide a competitive advantage to other more lethal organisms. Decolonization protocols which indiscriminately neutralize all bacteria may not be the best approach. If a patient's microbiome is markedly challenged with antimicrobials, rebuilding it with replacement commensal bacteria may become a future therapy. Preoperative MRSA surveillance allows the selection of appropriate prophylactic antibiotics, the use of extended decolonization protocols in positive patients, and provides needed data for epidemiological studies.
Project description:BACKGROUND:Sufficient details have not been specified for the epidemiological characteristics of Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA) among surgical site infections (SSIs) in mainland China. This systematic review aimed to estimate proportions of S. aureus and MRSA in SSIs through available published studies. METHODS:PubMed, Embase and four Chinese electronic databases were searched to identify relevant primary studies published between 2007 and 2012. Meta-analysis was conducted on the basis of logit-transformed metric for proportions of S. aureus and MRSA, followed by pre-defined subgroup meta-analysis. Random-effects meta-regression was also conducted to explore the impact of possible factors on S. aureus proportions. RESULTS:106 studies were included, of which 38 studies involved MRSA. S. aureus accounted for 19.1% (95%CI 17.2-21.0%; I(2) = 84.1%) of all isolates in SSIs, which was roughly parallel to 18.5% in the United States (US) (P-value = 0.57) but significantly exceeded those calculated through the surveillance system in China (P-value<0.001). In subgroup analysis, S. aureus in patients with thoracic surgery (41.1%, 95%CI 26.3-57.7%; I(2) = 74.4%) was more common than in those with gynecologic surgery (20.1%, 95%CI 15.6-25.6%; I(2) = 33.0%) or abdominal surgery (13.8%, 95%CI 10.3-18.4%; I(2) = 70.0%). Similar results were found in meta-regression. MRSA accounted for 41.3% (95%CI 36.5-46.3%; I(2) = 64.6%) of S. aureus, significantly lower than that in the US (P-value = 0.001). MRSA was sensitive to vancomycin (522/522) and linezolid (93/94), while 79.9% (95%CI 67.4-88.4%; I(2) = 0%) and 92.0% (95%CI 80.2-97.0%; I(2) = 0%) of MRSA was resistant to clindamycin and erythromycin respectively. CONCLUSION:The overall proportion of S. aureus among SSIs in China was similar to that in the US but seemed higher than those reported through the Chinese national surveillance system. Proportions of S. aureus SSIs may vary with different surgery types. Commonly seen in SSIs, MRSA tended to be highly sensitive to vancomycin and linezolid but mostly resistant to clindamycin and erythromycin.
Project description:BackgroundMandatory reporting of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) has occurred in England for over 15years. Epidemiological information is recorded, but routine collection of isolates for characterisation has not been routinely undertaken. Ongoing developments in whole-genome sequencing (WGS) have demonstrated its value in outbreak investigations and for determining the spread of antimicrobial resistance and bacterial population structure. Benefits of adding genomics to routine epidemiological MRSA surveillance are unknown.AimTo determine feasibility and potential utility of adding genomics to epidemiological surveillance of MRSA.MethodsWe conducted an epidemiological and genomic survey of MRSA BSI in England over a 1-year period (1 October 2012--30 September 2013).ResultsDuring the study period, 903 cases of MRSA BSI were reported; 425 isolates were available for sequencing of which, 276 (65%) were clonal complex (CC) 22. Addition of 64 MRSA genomes from published outbreak investigations showed that the study genomes could provide context for outbreak isolates and supported cluster identification. Comparison to other MRSA genome collections demonstrated variation in clonal diversity achieved through different sampling strategies and identified potentially high-risk clones e.g. USA300 and local expansion of CC5 MRSA in South West England.ConclusionsWe demonstrate the potential utility of combined epidemiological and genomic MRSA BSI surveillance to determine the national population structure of MRSA, contextualise previous MRSA outbreaks, and detect potentially high-risk lineages. These findings support the integration of epidemiological and genomic surveillance for MRSA BSI as a step towards a comprehensive surveillance programme in England.
Project description:Staphylococcus aureus is an important pathogen causing a spectrum of diseases ranging from mild skin and soft tissue infections to life-threatening conditions. Bloodstream infections are particularly important, and the treatment approach is complicated by the presence of methicillin-resistant S. aureus (MRSA) isolates. The emergence of new genetic lineages of MRSA has occurred in Latin America (LA) with the rise and dissemination of the community-associated USA300 Latin American variant (USA300-LV). Here, we prospectively characterized bloodstream MRSA recovered from selected hospitals in 9 Latin American countries. All isolates were typed by pulsed-field gel electrophoresis (PFGE) and subjected to antibiotic susceptibility testing. Whole-genome sequencing was performed on 96 MRSA representatives. MRSA represented 45% of all (1,185 S. aureus) isolates. The majority of MRSA isolates belonged to clonal cluster (CC) 5. In Colombia and Ecuador, most isolates (?72%) belonged to the USA300-LV lineage (CC8). Phylogenetic reconstructions indicated that MRSA isolates from participating hospitals belonged to three major clades. Clade A grouped isolates with sequence type 5 (ST5), ST105, and ST1011 (mostly staphylococcal chromosomal cassette mec [SCCmec] I and II). Clade B included ST8, ST88, ST97, and ST72 strains (SCCmec IV, subtypes a, b, and c/E), and clade C grouped mostly Argentinian MRSA belonging to ST30. In summary, CC5 MRSA was prevalent in bloodstream infections in LA with the exception of Colombia and Ecuador, where USA300-LV is now the dominant lineage. Clonal replacement appears to be a common phenomenon, and continuous surveillance is crucial to identify changes in the molecular epidemiology of MRSA.