Proportion Of Methicillin-resistant Staphylococcus Aureus Research Articles

Antibiotic consumption as a driver for resistance in Staphylococcus aureus and Escherichia coli within a developing region

This study aimed to provide insight into possible antibiotic drivers of methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli resistant to third-generation cephalosporins (3GCREC) in southern and eastern Mediterranean institutions. MRSA and 3GCREC susceptibility proportions from 19 regional hospitals, previously published by the ARMed project, were correlated with antibiotic use data from the same institutions. Hospitals reporting below-median MRSA proportions had significantly lower total antibiotic use. MRSA proportions increased with greater use of carbapenems (P=.04). In multivariate analysis, a positive correlation was identified with the use of carbapenems (P=.002), combination penicillins (P=.018), and aminoglycosides (P=.014). No difference was ascertained between 3GCREC proportions and total antibiotic use. In multivariate linear regression, a correlation was identified only for 3GCREC (P=.005), but a negative association was evident for beta-lactamase-resistant penicillins (P=.010) and first-generation cephalosporins (P=.012). The results suggest an association between resistance and antibiotic use, especially for carbapenems and third-generation cephalosporins. These data support the urgent implementation of antibiotic stewardship initiatives in hospitals in developing countries that focus on more judicious use of broad-spectrum formulations.

French National Program for Prevention of Healthcare-Associated Infections and Antimicrobial Resistance, 1992–2008: Positive Trends, But Perseverance Needed

To describe the French program for the prevention of healthcare-associated infections and antibiotic resistance and provide results for some of the indicators available to evaluate the program. In addition to structures and process indicators, the 2 outcome indicators selected were the rate of surgical site infection and the proportion of methicillin-resistant Staphylococcus aureus (MRSA) isolates among the S. aureus isolates recovered. Descriptive study of the evolution of the national structures for control of healthcare-associated infections since 1992. Through national surveillance networks, process indicators were available from 1993 to 2006, surgical site infection rates were available from 1999 to 2005, and prevalence rates for MRSA infection were available from 2001 to 2007. A comprehensive national program has gradually been set up in France during the period from 1993 to 2004, which included strengthening of organized infection control activities at the local, regional, and national levels and developing large networks for surveillance of specific infections and antibiotic resistance. These achievements were complemented by instituting mandatory notification for unusual nosocomial events, especially outbreaks. The second phase of the program involved the implementation of 5 national quality indicators with public reporting. Surgical site infection rates decreased by 25% over a 6-year period. In France, the median proportion of MRSA among S. aureus isolates recovered from patients with bacteremia decreased from 33.4% to 25.7% during the period from 2001 to 2007, whereas this proportion increased in many other European countries. Very few national programs have been evaluated since the Study on the Efficacy of Nosocomial Infection Control. Although continuing efforts are required, the French program appears to have been effective at reducing infection rates.

MRSA-Prävalenz in medizinischen und pflegerischen Einrichtungen eines Landkreises

In recent years multi-resistant pathogens, particularly methicillin-resistant Staphylococcus aureus (MRSA) have been causing increasing problems in hospitals and nursing homes. In Germany area-wide and interdisciplinary studies of prevalence of MRSA have not previously been conducted. For this reason we investigated the its prevalence in a cross-sectional study, which included patients in hospitals, rehabilitation centers and nursing homes in a rural district in Germany. The MRSA prevalence was determined by obtaining cultures from the nose, throat and any existing skin lesions of each patient in medical institutions and nursing homes in the the Höxter district. The presence of methicillin resistance, Panton-Valentine leukocidin (PVL) gene were determined and and staphylococcal protein A (spa) typing was done. Potential risk factors for MRSA colonization were also determined. S. aureus was isolated from 319 of 1 083 patients (614 females, 469 males; median age 68,2 years) from five hospitals, five nursing homes und three rehabilitation centers. The MRSA prevalence was 2,5% (95% confidence interval (CI) 1,7-3,7%). In hospitals the MRSA prevalence was 3,4%, in the nursing homes 2,3% and in rehabilitation centers 1,2%, without any significant difference between these three establishments. The proportion of MRSA in all S. aureus isolates was 8,5%. The PVL gene was not detected. It was found by multivariate analysis that variables independently associated with evidence of MRSA were haemodialysis (odds ratio (OR) 11,2; 95% CI 1,9-67,4) and an acute infection in the six months before hospital admission (OR 6,5; 95% CI 1,5-29,2). The spa typing showed different regional distribution of the MRSA subtypes. With 30% the spa type t003 (ST225 clone; in Germany called "Rhine-Hessen strain") occurred most frequently, followed by t032 with 22,2% (ST22 clone, also called "Barnimer strain"). This first regional cross-sectional study provides supportive data for MRSA surveillance in Germany and the data provide a basis for additional preventative measures.

Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in invasive isolates from southern and eastern Mediterranean countries

Efforts aimed at curtailing the ever increasing spread of methicillin-resistant Staphylococcus aureus (MRSA) require effective information of its epidemiology. However, knowledge about the situation in southern and eastern countries of the Mediterranean is incomplete since reports have been sporadic and difficult to compare. Over a 36 month period from 2003 to 2005, the ARMed project collected more than 5000 susceptibility test results of invasive isolates of S. aureus from blood cultures routinely processed within participating laboratories servicing 62 hospitals situated in Algeria, Cyprus, Egypt, Jordan, Lebanon, Malta, Morocco, Tunisia and Turkey. Overall, the median MRSA proportion was 39% (interquartile range: 27.1% to 51.1%). The highest proportions of MRSA were reported by Jordan, Egypt and Cyprus, where more than 50% of the invasive isolates were methicillin-resistant. Considerable variation was identified in the proportion of MRSA in hospitals within the same country. It appears that most of the countries in the Mediterranean region are experiencing a surge in MRSA infections. This requires a greater focus to identify relevant drivers of resistance and implement effective practices in order to address them, especially improved infection control and antibiotic consumption practices.

Determinants of Glycopeptides Consumption in Hospitals

The aim of this study was to describe consumption of glycopeptides and to study factors associated with their use in 47 French hospitals. Consumption of glycopeptides for systemic use (defined daily doses per 1,000 patient-days: DDD/1,000 PD and per 100 admissions), number of methicillin-resistant Staphylococcus aureus (MRSA) (percentage and incidence per 1,000 patient-days), and number of venous central lines and hospital characteristics (size, length of stay, number of beds: total and for each hospital inpatient areas and antibiotic policies) were recorded from January, 2002, through December, 2002. Multiple linear regression was performed to check for hospital characteristics. The median rate of total consumption of glycopeptides was 4.11(range 0.21-27.22) DDD per 1,000 PD with higher consumption in large public hospitals and in intensive care areas (median 46.51; range 7.19-134) than in surgery areas (median 4.5; range 0.17-24.76). The consumption of glycopeptides correlated with MRSA incidence, but not with the proportion of MRSA. In the multivariate analysis, the incidence of MRSA and the number of beds in surgery areas were independent predictors of total glycopeptides use in the hospital, expressed in DDD per 1,000 PD (R2 adjusted, 0.39). The incidence of MRSA, the number of venous central lines, and the number of beds in the medicine areas were significant determinants associated with higher consumption of glycopeptides expressed in DDD per 100 admissions (R2 adjusted, 0.73). To reduce glycopeptides use in hospitals, the first effort required is that hospitals focus increased attention on the prevention of cross transmission for MRSA between patients but also on the use of the venous central line. Furthermore, hospitals have to compare their data with others to identify overuse of glycopeptides and to plan control interventions.

Methicillin resistant Staphylococcus aureus: is it a problem for nasal surgery?

Methicillin resistant Staphylococcus aureus (MRSA) is becoming ever more prevalent in the UK, and the proportion of MRSA to methicillin sensitive Staphylococcus aureus (MSSA) seems to be increasing. New strains of MRSA are ever developing resistance to antibiotic treatment, increasing morbidity and mortality of infection. Staphylococcus aureus is part of the normal flora of the nose, and MRSA colonizes the nose in infection. However, nasal surgery is rarely complicated by staphylococcal infections, and MRSA infection following nasal surgery is rare. The authors present a literature review of MRSA infection, its relation to the nasal cavity, and infection following nasal surgery.

Impact of the reinforcement of a Methicillin-Resistant Staphylococcus aureus Control Programme: A 3-year evaluation by several indicators in a French University Hospital

Our objective was to evaluate the impact of the reinforcement of a methicillin-resistant Staphylococcus aureus (MRSA) control programme and to assess the impact of risk adjustment on the interpretation of data. A stepwise, retrospective analysis of 3-year prospectively collected data was performed in a 600-bed French teaching hospital in the Parisian area. A reinforcement of a pre-existing programme for limiting the spread of MRSA was implemented in 2002 and 2003 by increasing the frequency of the feedback of surveillance data, by using alcohol-based disinfectants, and by increasing patient screening. Different indicators were used to follow the change over time of MRSA transmission: the proportion of MRSA acquired in our hospital, the incidence of newly acquired MRSA/1,000 patient-days (PD) (incidence of newly acquired MRSA), the incidence of newly acquired MRSA isolated in at least one clinical specimen/1,000 PD (incidence of newly acquired clinical MRSA), and a risk-adjusted indicator, the incidence of newly acquired-MRSA isolated in at least one clinical specimen/1,000 PD of carriers identified at admission (incidence related to the risk of acquisition). The change over time of these indicators was studied with the chi-square test for trend. During the study, all indicators decreased significantly, with a mean drop of 0.07/1,000 PD for the incidence of newly acquired clinical MRSA, and a mean drop of 3.0/1,000 PD for the incidence related to the risk of acquisition. The proportion of MRSA acquired in our hospital decreased from 49.3% in 2002 to 24.1% in 2004. Concurrently, between 2002 and 2004, the number of patients screened on admission to hospital or at the time of intra-hospital transfer increased by 31% and the consumption of waterless alcohol-based hand disinfectants increased by 244%. The decreasing trend of all indicators emphasizes the effectiveness of the reinforcement of our MRSA control programme. From 2002 to 2004, the trend of the indicator related to the risk of acquisition over time is similar to those of other indicators. Further studies should be useful to assess if risk-adjustment is absolutely necessary when tracking rates within a single institution.

Methicillin-resistantStaphylococcus aureus, Hawaii, 2000–2002

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has generated considerable concern among medical and public health professionals. We used a statewide, population-based antimicrobial resistance surveillance system to examine epidemiologic trends for MRSA from outpatients and inpatients in Hawaii. Pediatric and adult patient populations were compared to assess characteristics of MRSA isolates specific for each group. From 2000 to 2002, 8,206 (26%) of 31,482 total S. aureus isolates were MRSA. During this period, the proportion of MRSA isolates increased in both outpatient and inpatient clinical settings (p<0.01). When stratified by age, annual trends showed a significant increase in the proportion of MRSA in adult patients (from 24% to 30%, p<0.01) but not in pediatric patients (from 25% to 27%, p>0.05). Although MRSA isolates from adults demonstrated high resistance to most non-beta-lactams, most MRSA isolates from pediatric outpatients remained susceptible to most non-beta-lactams.

Methicillin-resistantStaphylococcus aureusin Europe, 1999–2002

We explored the variation in proportions of methicillin-resistant Staphylococcus aureus (MRSA) between and within countries participating in the European Antimicrobial Resistance Surveillance System and temporal trends in its occurrence. This system collects routine antimicrobial susceptibility tests for S. aureus. We examined data collected from January 1999 through December 2002 (50,759 isolates from 495 hospitals in 26 countries). MRSA prevalence varied almost 100-fold, from <1% in northern Europe to >40% in southern and western Europe. MRSA proportions significantly increased in Belgium, Germany, Ireland, the Netherlands, and the United Kingdom, and decreased in Slovenia. Within countries, MRSA proportions varied between hospitals with highest variance in countries with a prevalence of 5% to 20%. The observed trends should stimulate initiatives to control MRSA at national, regional, and hospital levels. The large differences between hospitals indicate that efforts may be most effective at regional and hospital levels.

La méticillino-résistance de Staphylococcus aureus isolés à Abidjan (1998–2001) : un nouveau problème en milieu hospitalier

Objective. – The authors had for aim to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains on infections in Abidjan as well as their susceptibility to other antibiotics. Methods. – Three hundred and forty strains of S. aureus from various samples of hospitalized patients were studied. Methicillin-resistance was assessed using oxacillin disk diffusion in agar. The MRSA, once detected, were confirmed by screening in Mueller-Hinton agar containing oxacillin at 6 μg/ml. The susceptibility to other antibiotics was analyzed using an antibiogram in agar medium. Results. – Twenty-five percent of strains were resistant to methicillin (MRSA strains). Those MRSA were identified mainly in blood culture (14.2%), pus (4%) and urine (1.9%). Samples were collected in neonatal unit (13%), surgical units (5.4%) and intensive care unit (3.4%). A variable proportion of MRSA expressed resistance to other families of antibiotics: aminoglycosides 77.6%, rifampicin 8.8%, fluoroquinolones 34.1% and vancomycin 5.9%. Conclusion. – Circulation of multidrug resistant MRSA in hospital, especially in neonatal unit, should lead to surveillance. Risk factors and other associated markers need to be identified.

Community-acquired methicillin-resistant Staphylococcus aureus, Finland.

Methicillin-resistant Staphylococcus aureus (MRSA) is no longer only hospital acquired. MRSA is defined as community acquired if the MRSA-positive specimen was obtained outside hospital settings or within 2 days of hospital admission, and if it was from a person who had not been hospitalized within 2 years before the date of MRSA isolation. To estimate the proportion of community-acquired MRSA, we analyzed previous hospitalizations for all MRSA-positive persons in Finland from1997 to 1999 by using data from the National Hospital Discharge Register. Of 526 MRSA-positive persons, 21% had community-acquired MRSA. Three MRSA strains identified by phage typing, pulsed-field gel electrophoresis, and ribotyping were associated with community acquisition. None of the strains were multiresistant, and all showed an mec hypervariable region hybridization pattern A (HVR type A). None of the epidemic multiresistant hospital strains were prevalent in nonhospitalized persons. Our population-based data suggest that community-acquired MRSA may also arise de novo, through horizontal acquisition of the mecA gene.

Are all MRSA made equal?

The health and economic burden of methicillin-resistant Staphylococcus aureus (MRSA) in the medical realm is considerable. Although there is ample clinical and laboratory evidence indicating that methicillin-susceptible S. aureus (MSSA) is heterogeneous in disease causation, the same heterogeneity has not been well documented for MRSA. Data from animal models and human studies suggest that MRSA is at least as pathogenic as MSSA. Many comparative clinical studies, mainly retrospective, have assessed the virulence of MSSA and MRSA. Whereas the majority of these studies may be deficient in some aspects of clinical design, there has been a definite trend towards implicating MRSA as the more aggressive pathogen. Such an observation, however, must be tempered with the fact that few such studies have attempted to establish clonality among MRSA isolates. Thus, it is conceivable that hypervirulent clones may represent an important proportion of MRSA from hospital studies where patient-patient spread is likely and, accordingly, comparative studies may be biased. Future clinical studies should be prospective and should use well-defined and homogeneous patient groups. As well, for comparison of MRSA and MSSA, an understanding of clonality is essential.

Methicillin-resistance among Turkish isolates of Staphylococcus aureus strains from nosocomial and community infections and their resistance patterns using various antimicrobial agents

The purposes of this study were to determine the prevalence of Turkish isolates of methicillin-resistant Staphylococcus aureus (MRSA) in nosocomial and community infections and their antibiotic resistant patterns. The oxacillin disk diffusion method for the detection of methicillin resistance and the Kirby-Bauer disk diffusion for antibiotic susceptibility tests were used. A total 383 S. aureus strains were identified from different patients. The prevalence of methicillin resistance among S. aureus strains was 31·3% ( 120 383 ). The proportions of MRSA isolated from nosocomial and community infections were 26·4% ( 46 174 ) and 35·4% ( 74 209 ), respectively. The resistance rates of MRSA to other antibiotics were as follows: 71% resistant to erythromycin, 54% to clindamycin, 52% to gentamicin, 44·5% to trimethoprim-sulfamethoxazole and 36% to ciprofloxacin. No strain resistant to vancomycin was recorded in this study.

Methicillin-resistant Staphylococcus aureus in Europe.

In order to obtain pan-European data on methicillin-resistant Staphylococcus aureus (MRSA), 43 laboratories from ten European countries each screened 200 consecutive Staphylococcus aureus isolates for methicillin resistance. Only one isolate per patient was permitted. All participants used a uniform oxacillin-supplemented screening plate. MRSA isolates were sent to Munich for reconfirmation and further susceptibility testing. Phage typing of the MRSA strains was performed in Denmark. Of the 7,333 Staphylococcus aureus strains screened, 936 (12.8%) were methicillin resistant. The proportion of MRSA in the various European countries ranged from < 1% in Scandinavia to > 30% in Spain, France and Italy. Rates of resistance to the non-glycopeptide antibiotics were lowest for rifampin and highest for ciprofloxacin. Sixty percent of the methicillin-resistant strains originated from patients in surgical and medical departments, with wounds being the most common isolation source. MRSA was found more frequently in intensive care patients. Only 13% of the strains were non-typable, and 76% of the isolates belonged to phage group III. For each area phage typing detected one or a few dominating (epidemic) types, but 46% of the strains did not belong to these types; the MRSA population is thus a mixture of epidemic and non-epidemic strains. MRSA seems to be a growing problem, especially in southern Europe, where incidence and rates of antibiotic resistance are alarmingly high.