Guidelines for the control and prevention of meticillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities

Tea tree oil (5%) body wash versus standard care (Johnson's Baby Softwash) to prevent colonization with methicillin-resistant Staphylococcus aureus in critically ill adults: a randomized controlled trial

OBJECTIVES

To determine whether the daily use of 5% tea tree oil (TTO) body wash (Novabac 5% Skin Wash) compared with standard care [Johnson's Baby Softwash (JBS)] had a lower incidence of methicillin-resistant Staphylococcus aureus (MRSA) colonization.

PATIENTS

The study setting was two intensive care units (ICUs; mixed medical, surgical and trauma) in Northern Ireland between October 2007 and July 2009. The study population comprised 391 patients who were randomized to JBS or TTO body wash.

METHODS

This was a Phase 2/3, prospective, open-label, randomized, controlled trial.

TRIAL REGISTRATION

ISRCTN65190967. The primary outcome was new MRSA colonization during ICU stay. Secondary outcomes included the incidence of MRSA bacteraemia and maximum increase in sequential organ failure assessment score.

RESULTS

A total of 445 patients were randomized to the study. After randomization, 54 patients were withdrawn; 30 because of a positive MRSA screen at study entry, 11 due to lack of consent, 11 were inappropriately randomized and 2 had adverse reactions. Thirty-nine (10%) patients developed new MRSA colonization (JBS n = 22, 11.2%; TTO body wash n = 17, 8.7%). The difference in percentage colonized (2.5%, 95% CI - 8.95 to 3.94; P = 0.50) was not significant. The mean maximum increase in sequential organ failure assessment score was not significant (JBS 1.44, SD 1.92; TTO body wash 1.28, SD 1.79; P = 0.85) and no study patients developed MRSA bacteraemia.

CONCLUSIONS

Compared with JBS, TTO body wash cannot be recommended as an effective means of reducing MRSA colonization.

Quantifying the impact of extranasal testing of body sites for methicillin-resistant Staphylococcus aureus colonization at the time of hospital or intensive care unit admission

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of healthcare-associated infections. Recent legislative mandates require nares screening for MRSA at hospital and intensive care unit (ICU) admission in many states. However, MRSA colonization at extranasal sites is increasingly recognized. We conducted a systematic review of the literature to identify the yield of extranasal testing for MRSA.

DESIGN

We searched MEDLINE from January 1966 through January 2012 for articles comparing nasal and extranasal screening for MRSA colonization. Studies were categorized by population tested, specifically those admitted to ICUs and those admitted to hospitals with a high prevalence (6% or greater) or low prevalence (less than 6%) of MRSA carriers. Data were extracted using a standardized instrument.

RESULTS

We reviewed 4,381 abstracts and 735 articles. Twenty-three articles met the criteria for analysis ((n = 39,479 patients). Extranasal MRSA screening increased the yield by approximately one-third over nares alone. The yield was similar at ICU admission (weighted average, 33%; range, 9%-69%) and hospital admission in high-prevalence (weighted average, 37%; range, 9%-86%) and low-prevalence (weighted average, 50%; range, 0%-150%) populations. For comparisons between individual extranasal sites, testing the oropharynx increased MRSA detection by 21% over nares alone; rectum, by 20%; wounds, by 17%; and axilla, by 7%.

CONCLUSIONS

Extranasal MRSA screening at hospital or ICU admission in adults will increase MRSA detection by one-third compared with nares screening alone. Findings were consistent among subpopulations examined. Extranasal testing may be a valuable strategy for outbreak control or in settings of persistent disease, particularly when combined with decolonization or enhanced infection prevention protocols.

The potential regional impact of contact precaution use in nursing homes to control methicillin-resistant Staphylococcus aureus

OBJECTIVE

Implementation of contact precautions in nursing homes to prevent methicillin-resistant Staphylococcus aureus (MRSA) transmission could cost time and effort and may have wide-ranging effects throughout multiple health facilities. Computational modeling could forecast the potential effects and guide policy making.

DESIGN

Our multihospital computational agent-based model, Regional Healthcare Ecosystem Analyst (RHEA).

SETTING

All hospitals and nursing homes in Orange County, California.

METHODS

Our simulation model compared the following 3 contact precaution strategies: (1) no contact precautions applied to any nursing home residents, (2) contact precautions applied to those with clinically apparent MRSA infections, and (3) contact precautions applied to all known MRSA carriers as determined by MRSA screening performed by hospitals.

RESULTS

Our model demonstrated that contact precautions for patients with clinically apparent MRSA infections in nursing homes resulted in a median 0.4% (range, 0%-1.6%) relative decrease in MRSA prevalence in nursing homes (with 50% adherence) but had no effect on hospital MRSA prevalence, even 5 years after initiation. Implementation of contact precautions (with 50% adherence) in nursing homes for all known MRSA carriers was associated with a median 14.2% (range, 2.1%-21.8%) relative decrease in MRSA prevalence in nursing homes and a 2.3% decrease (range, 0%-7.1%) in hospitals 1 year after implementation. Benefits accrued over time and increased with increasing compliance.

CONCLUSIONS

Our modeling study demonstrated the substantial benefits of extending contact precautions in nursing homes from just those residents with clinically apparent infection to all MRSA carriers, which suggests the benefits of hospitals and nursing homes sharing and coordinating information on MRSA surveillance and carriage status.

Smart bandages--a colourful approach to early stage infection detection & control in wound care

With the recent increase in bacterial resistance to conventional antibiotics, the early-stage detection and control of infection has become imperative in the fight against opportunistic pathogens in healthcare. The traditional β-lactam wonder-drugs (e.g. penicillin and cephalosporins), are rendered inactive due to enzymatic hydrolysis by bacterial β-lactamase enzymes as a bacterial defence mechanism. However, this deactivation mechanism produces different responses in the two aforementioned drugs - with the cephalosporins showing a molecular rearrangement mechanism which could be utilised for prodrug delivery. This unique mechanism could mean that inactive forms of cephalosporin antibiotics, once used as chemotherapeutics in oncology, could once again be used in the fight against disease as sensors to detect and treat bacterial colonisation. Therefore, we hypothesize that cephalosporin-dye bandages might provide an effective method to visually detect, and subsequently control, the early stages of an infection using photoantimicrobial chemotherapy (PACT).

Secular trends in nosocomial bloodstream infections: antibiotic-resistant bacteria increase the total burden of infection

BACKGROUND

It is unknown whether rising incidence rates of nosocomial bloodstream infections (BSIs) caused by antibiotic-resistant bacteria (ARB) replace antibiotic-susceptible bacteria (ASB), leaving the total BSI rate unaffected.

METHODS

We investigated temporal trends in annual incidence densities (events per 100 000 patient-days) of nosocomial BSIs caused by methicillin-resistant Staphylococcus aureus (MRSA), ARB other than MRSA, and ASB in 7 ARB-endemic and 7 ARB-nonendemic hospitals between 1998 and 2007.

RESULTS

33 130 nosocomial BSIs (14% caused by ARB) yielded 36 679 microorganisms. From 1998 to 2007, the MRSA incidence density increased from 0.2 to 0.7 (annual increase, 22%) in ARB-nonendemic hospitals, and from 3.1 to 11.7 (annual increase, 10%) in ARB-endemic hospitals (P = .2), increasing the incidence density difference between ARB-endemic and ARB-nonendemic hospitals from 2.9 to 11.0. The non-MRSA ARB incidence density increased from 2.8 to 4.1 (annual increase, 5%) in ARB-nonendemic hospitals, and from 1.5 to 17.4 (annual increase, 22%) in ARB-endemic hospitals (P < .001), changing the incidence density difference from -1.3 to 13.3. Trends in ASB incidence densities were similar in both groups (P = .7). With annual increases of 3.8% and 5.4% of all nosocomial BSIs in ARB-nonendemic and ARB-endemic hospitals, respectively (P < .001), the overall incidence density difference of 3.8 increased to 24.4.

CONCLUSIONS

Increased nosocomial BSI rates due to ARB occur in addition to infections caused by ASB, increasing the total burden of disease. Hospitals with high ARB infection rates in 2005 had an excess burden of BSI of 20.6 per 100 000 patient-days in a 10-year period, mainly caused by infections with ARB.

Methicillin-resistant Staphylococcus aureus nasal carriage among patients receiving hemodialysis in Taiwan: prevalence rate, molecular characterization and de-colonization

BACKGROUND

Staphylococcus aureus, particularly methicillin resistant (MRSA), is a common pathogen among patients receiving hemodialysis. To evaluate nasal carriage, molecular characterization and effectiveness of decolonization of MRSA among patients receiving hemodialysis in Taiwan, we conducted this study.

METHODS

From January to June 2011, two nasal samplings with a 3-month interval were obtained from patients undergoing hemodialysis in a medical center (CGMH), and in a local hospital (YMH) and sent for detection of MRSA. For MRSA carriers, decolonization procedures were administered. All patients in CGMH were observed if MRSA infections occurred during the study period.

RESULTS

A total of 529 nasal specimens (265 from CGMH and 264 from YMH) were collected from 296 patients (161 from CGMH and 135 from YMH). 233 patients participated in both surveys. Average one-time point MRSA carriage rate was 3.8%, and the rate was up to 6.9% for those with two-time point surveys. No additional significant factor for MRSA carriage was identified. Seventy percent of the 20 colonizing MRSA isolates, though categorized as healthcare-associated strains epidemiologically, shared common molecular characteristics of the local community-associated strains. Only one of the 20 MRSA-colonized patients failed decolonization and had persistent colonization, while without any intervention, 17 (61%) of 28 patients with methicillin-sensitive S. aureus colonization in the first survey had persistent colonization of a genetically indistinguishable strain. Within the study period, two patients (1.24%) in CGMH, one with MRSA colonization (9.1%), developed MRSA infection.

CONCLUSION

A substantial proportion of patients receiving hemodialysis in Taiwan had MRSA colonization, mostly genetically community strains. Decolonization procedures may effectively eliminate MRSA colonization and might reduce subsequent MRSA infection in these patients.

Three years' experience of screening for meticillin-resistant Staphylococcus aureus in obstetrics

There are few data on meticillin-resistant Staphylococcus aureus (MRSA) screening in obstetrics, a largely healthy population that should be at lower risk for MRSA than most hospitalized populations. From January 2009 to December 2011 nose swabs were screened from 5548 of 21,770 (25.5%) women who delivered at Birmingham Women's Hospital. Only 29 (0.5%) were MRSA positive: MRSA infections occurred later in three cases. MRSA infections occurred in a further 13 mother-infant pairs, including six cases where mothers were MRSA screen negative. Seventeen mothers had risk factors for MRSA. MRSA is not widespread in obstetrics, and large-scale screening of nasal swabs is of limited value in preventing MRSA-related morbidity in this population.

Meticillin-resistant Staphylococcus aureus screening in Wales: survey of practices in adult critical care units in Welsh hospitals

Screening for meticillin-resistant Staphylococcus aureus (MRSA) carriage in critical care units remains a controversial issue. This cross-sectional study reviewed the MRSA screening policies in adult critical care units in Welsh hospitals. Data were collected by structured questionnaires. The study showed a degree of variability in practice from universal screening to no screening at all. It is recommended that local MRSA policies should be reviewed, bearing in mind the local prevalence of colonization and infection; and compliance with basic infection control strategies should not only be directed at MRSA infection, but also at other healthcare-associated infections.

Comparison of two commercial PCR methods for methicillin-resistant Staphylococcus aureus (MRSA) screening in a tertiary care hospital

Nose/throat-swabs from 1049 patients were screened for MRSA using CHROMagar MRSA, LightCycler Advanced MRSA, and Detect-Ready MRSA. Results were compared to the CHROMagar MRSA results, which was set as reference system. MRSA was detected in 3.05% of the patients with CHROMagar MRSA. LightCycler MRSA Advanced showed a higher clinical sensitivity (84.38%) than Detect-Ready MRSA (57.69%).The negative predictive values were high for both tests (>98%). The specificity and the positive predictive value were higher for the Detect-Ready MRSA test than for the LightCycler MRSA test (99.59% and 78.95% versus 98.52% and 64.29%). For routine screening LightCycler MRSA Advanced proved to be more efficient in our clinical setting as the clinical sensitivity was much higher than the sensitivity of Detect-Ready MRSA. CHROMagar MRSA detected more MRSA positive samples than both PCR methods, leading to the conclusion that the combination of PCR with cultural screening is still the most reliable way for the detection of MRSA. LightCycler MRSA Advanced was faster and needed less hands-on time. The advantage of Detect-Ready MRSA was the additional identification of methicillin-sensitive S.aureus (here in 34.63% of the samples), an information which can be possibly used for reducing the risk of postoperative infections in surgical patients in future.

Methicillin-resistant Staphylococcus aureus epidemic restricted to one health district in Finland: a population-based descriptive study in Pirkanmaa, Finland, years 2001-2011

BACKGROUND

The incidence of methicillin-resistant Staphylococcus aureus (MRSA) has been low in the Scandinavian countries, including Finland.

METHODS

We report a population-based, prospective survey of an exceptionally large ongoing MRSA epidemic in a Finnish health district (HD), Pirkanmaa HD, during 2001-2011 caused by 1 strain, spa t067 (FIN-16).

RESULTS

The first FIN-16 case in the HD was identified in 2000. Ten years later, 2447 carriers had been found in 95 different institutions. MRSA in carriers was mostly health care-associated (98%). The epidemic emerged in long-term care facilities and gradually spread to acute hospitals. The majority of carriers were elderly people (median age 78 y). Fifty-two percent of new carriers had an infection with MRSA at the time of detection.

CONCLUSIONS

The incidence of MRSA in Pirkanmaa HD is substantially higher than the incidence for all of Finland. Temporary projects to control MRSA have not proved sufficient to contain this large epidemic.

Methicillin-resistant Staphylococcus aureus (MRSA) in an Austrian urological department: 10 years experience covering 95.161 patients

PURPOSE

So far, few data is available on Methicillin-resistant Staphylococcus aureus (MRSA) infections in urology. To obtain a better insight into MRSA infections, we studied prevalence, colonization and infection site and clinical implications of MRSA in a urological department over a 10-year period.

METHODS

A retrospective study of all patients diagnosed with MRSA for the first time over a 10-year period was set-up.

RESULTS

Between 2000 and 2009, a total of 95.161 in- and outpatients were seen at our department. The prevalence of patients with newly diagnosed MRSA was low, that is, <0.1 % per year (mean 0.07%, 0.02-0.1 %). In total, 62 MRSA cases were identified over a 10-year period. MRSA incidence was 10 times higher in inpatients (0.2 %) than in outpatients (0.02 %). Asymptomatic MRSA colonization was present in 25/62 patients (40.3 %), the remaining 59.7 % (37/62) showed clinical symptoms: MRSA positive swabs from open wounds were seen in 10/62 patients (16.1 %). Urinary tract infections were seen in 26/10 patients (41.9 %), while life-threatening MRSA sepsis occurred in one patient only over a decade.

CONCLUSIONS

In summary, we observed very low rates of MRSA colonization and infection. Still, complications like delayed wound healing, development of abscess and even sepsis may occur.

A novel resistance mechanism to triclosan that suggests horizontal gene transfer and demonstrates a potential selective pressure for reduced biocide susceptibility in clinical strains of Staphylococcus aureus

The widely used biocide triclosan selectively targets FabI, the NADH-dependent trans-2-enoyl-acyl carrier protein reductase, which is an important target for narrow-spectrum antimicrobial drug development. In relation to the growing concern about biocide resistance, we compared in vitro mutants and clinical isolates of Staphylococcus aureus with reduced triclosan susceptibility. Clinical isolates of S. aureus as well as laboratory-generated mutants were assayed for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) phenotypes and genotypes related to reduced triclosan susceptibility. A potential epidemiological cut-off (ECOFF) MBC of >4 mg/L was observed for triclosan in clinical isolates of S. aureus. These showed significantly lower MICs and higher MBCs than laboratory mutants. These groups of strains also had few similarities in the triclosan resistance mechanism. Molecular analysis identified novel resistance mechanisms linked to the presence of an additional sh-fabI allele derived from Staphylococcus haemolyticus. The lack of predictive value of in-vitro-selected mutations for clinical isolates indicates that laboratory tests in the present form appear to be of limited value. More importantly, detection of sh-fabI as a novel resistance mechanism with high potential for horizontal gene transfer demonstrates for the first time that a biocide could exert a selective pressure able to drive the spread of a resistance determinant in a human pathogen.

The prevalence of nasal carriage of meticillin resistant Staphylococcus aureus among healthcare workers in a non-acute healthcare facility

There is a lack of data available concerning the baseline prevalence of meticillin resistant Staphylococcus aureus (MRSA) carriage among healthcare workers (HCWs) in the Republic of Ireland. This anonymous prevalence study screened HCWs for nasal carriage of MRSA in a non-acute healthcare facility (HCF) in Dublin and the prevalence rate among these HCWs was calculated. Three hundred and four HCWs were invited to participate, with 112 (37%) consenting to take part in the study. Nasal swabs were analysed by culture method for MRSA with reference to Health Protection Agency guidelines. Meticillin resistant isolates were examined for presence of MecA gene by real-time polymerase chain reaction. The overall rate of nasal carriage MRSA was found to be 8.9% (10/112), of whom eight were nurses, one was medical staff and one was household/catering staff. High-level mupirocin resistance was detected in two of the isolates. This study confirms a significant prevalence of MRSA carriage among the cohort studied, particularly among frontline HCWs. This emphasises the need for strict adherence to infection control protocols to minimise healthcare associated MRSA infections among patients in non-acute healthcare facilities. The detection of high level mupirocin resistant MRSA has implications for MRSA decontamination protocols.

Community-associated meticillin-resistant Staphylococcus aureus: the case for a genotypic definition

BACKGROUND

New distinct strains of community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) have emerged as a cause of infection in previously healthy individuals in community settings. It is important to identify CA-MRSA for clinical management, epidemiological analysis, infection prevention and control, and regulatory reporting, but definitions and nomenclature of these strains are confused.

AIM

To review attempts to define CA-MRSA and propose a new definition.

METHODS

Non-systematic review.

FINDINGS

Epidemiological definitions were useful for differentiating CA-MRSA and healthcare-associated (HA)-MRSA strain types in the past. However, although HA-MRSA strain types are rarely transmitted in the community, CA-MRSA strains have started to be transmitted in healthcare facilities, so epidemiological definitions are breaking down. CA-MRSA are community strains of S. aureus that have acquired the meticillin resistance gene, mecA. They are distinct from HA-MRSA and should be defined genetically. This may be done by combining genotypic typing by multi-locus sequence or spa with analysis of the staphylococcal cassette chromosome mec. Carriage of Panton-Valentine leukocidin or antimicrobial susceptibility profiles can be useful indicators of CA-MRSA but should not be used for their definition.

CONCLUSION

For full assessment of their epidemiology, MRSA infections should be characterized as: (1) caused by HA- or CA-MRSA strain types; (2) acquired in community or healthcare settings; and (3) onset in the community or healthcare facility.

Epidemic spread of ST1-MRSA-IVa in a neonatal intensive care unit, Italy

BACKGROUND

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has recently emerged as an important pathogen in neonatal intensive care units (NICUs). The purposes of this study were to characterize methicillin-resistant isolates from an outbreak in a NICU, to examine the genetic traits and clonality of CA-MRSA, and to review the characteristics and outcomes of the neonatal cases and investigate the routes of entry and transmission of the MRSA outbreak strain in the NICU under study.

METHODS

The study NICU practiced an active surveillance program for multidrug-resistant organisms, including weekly cultures for detection of MRSA from nasal swabs among all the admitted neonates. All first isolates from surveillance cultures and all clinical isolates were submitted for susceptibility testing and genotyping. Data from each infant's medical records were prospectively included in a database, and the clinical features and outcomes of the colonized/infected infants were assessed.

RESULTS

A total of 14 infants were colonized or infected by a strain of ST1-MRSA-IVa between April and August 2011. The CA-MRSA strain appeared to have been introduced to the NICU by an infected infant transferred from another hospital. The outbreak was successfully contained by multifaceted infection control interventions.

CONCLUSIONS

The results of this study confirm that NICU is a healthcare setting with a critical permeability to CA-MRSA. Active surveillance including molecular typing can help to detect and monitor the spread of antimicrobial drug-resistant organisms, and thus trigger timely control interventions.

Carriage frequency, phenotypic and genotypic characteristics of Staphylococcus aureus isolated from dialysis and kidney tranplant patients at a hosptial in northern paraná

The objective of the present study was to determine the frequency of Staphylococcus aureus nasal carriage among dialysis and kidney transplant patients, to identify the antimicrobial resistance profile of these strains and to verify their genetic profiles with the RW3A primer. The study included 159 individuals, comprising 111 dialysis and 48 kidney transplant patients. Of the 48 transplant patients, 75% were positive for S. aureus, whereas 49% of the 111 dialysis patients were carriers. Two samples yielded conflicting results for oxacillin sensitivity between the disk diffusion and minimum inhibitory concentration (MIC) assays: both were sensitive by the disk diffusion assay and resistant by MIC (4 μg/ml). In the antibiogram by disk diffusion, ten samples were resistant to cefoxitin, among which eight were also resistant to oxacillin. The resistance of the ten samples to cefoxitin by the disk diffusion assay was confirmed by MIC. Of the ten oxacillin-resistant samples, eight harbored the mecA gene. All samples were sensitive to vancomycin, and most were resistant to penicillin and demonstrated high rates of resistance to the other antimicrobials tested. The samples from dialysis patients exhibited a more homogenous genetic profile. Among the samples with a high percent similarity, no correlation with sensitivity or resistance to oxacillin was observed. According to the results of this study, the implementation of prevention and control measures, such as increased restrictions on prescriptions for antimicrobial drugs and nasal decontamination prior to high-risk procedures, is recommended.

Patient experience of source isolation: lessons for clinical practice

Methicillin-resistant Staphylococcus aureus (MRSA) is now the leading antimicrobial-resistant organism of concern to clinicians worldwide. Preventing and controlling the increase and spread of MRSA within the health-care environment is therefore an important function of the infection control team. The prevention and control of MRSA requires strict use of both Standard and Additional Precautions, which include good hand hygiene practices, judicious antimicrobial prescribing, and source isolation. While few would dispute the need for these precautions for preventing the spread of MRSA and other infections, their use may result in adverse physical and psychological effects for the patient. In an age of quality and safety of health care, ensuring infection control practice such as source isolation and contact precautions adhere to fundamental human rights is paramount. This paper presents a review of the literature on the patient experience of source isolation for MRSA or other infectious diseases. The review yielded five major interconnected themes: (1) psychological effects of isolation; (2) coping with isolation; (3) social isolation; (4) communication and information provision; and (5) physical environment and quality of care. It found that the experience of isolation by patients has both negative and positive elements. Isolation may result in detrimental psychological effects including anxiety, stress and depression, but may also result in the patient receiving less or substandard care. However, patients may also benefit from the quietness and privacy of single rooms. Nurses and other healthcare workers must look for ways to improve the experience of isolation and contact precautions of patients in source isolation. Opportunities exist in particular in improving the environment and the patient's self-control of the situation and in providing adequate information.

Global analysis of the Staphylococcus aureus response to mupirocin

In the present study, we analyzed the response of S. aureus to mupirocin, the drug of choice for nasal decolonization. Mupirocin selectively inhibits the bacterial isoleucyl-tRNA synthetase (IleRS), leading to the accumulation of uncharged isoleucyl-tRNA and eventually the synthesis of (p)ppGpp. The alarmone (p)ppGpp induces the stringent response, an important global transcriptional and translational control mechanism that allows bacteria to adapt to nutritional deprivation. To identify proteins with an altered synthesis pattern in response to mupirocin treatment, we used the highly sensitive 2-dimensional gel electrophoresis technique in combination with mass spectrometry. The results were complemented by DNA microarray, Northern blot, and metabolome analyses. Whereas expression of genes involved in nucleotide biosynthesis, DNA metabolism, energy metabolism, and translation was significantly downregulated, expression of isoleucyl-tRNA synthetase, the branched-chain amino acid pathway, and genes with functions in oxidative-stress resistance (ahpC and katA) and putative roles in stress protection (the yvyD homologue SACOL0815 and SACOL1759 and SACOL2131) and transport processes was increased. A comparison of the regulated genes to known regulons suggests the involvement of the global regulators CodY and SigB in shaping the response of S. aureus to mupirocin. Of particular interest was the induced transcription of genes encoding virulence-associated regulators (i.e., arlRS, saeRS, sarA, sarR, sarS, and sigB), as well as genes directly involved in the virulence of S. aureus (i.e., fnbA, epiE, epiG, and seb).

[Colonization management of methicillin resistant Staphylococcus aureus in patients and health professional in the haemodialysis unit in a situation of high risk of endemic disease: looking for zero nasal carriers?]

AIMS

To describe the dynamics of colonization by methicillin resistant Staphylococcus aureus (MRSA) detected in the Haemodialysis Unit (UHD) of the Hospital San Pedro de Alcantara of Caceres due to the detection of catheter-associated infections. Additionally, we attempt to evaluate the effectiveness of preventive strategies introduced.

METHODS

Nasal swab tests were performed in order to detect MRSA colonization in patients and health professionals from August 2008 to January 2009, according to the Consensus GEIH-SEIMC Y SEMPSPH Consensus. An active surveillance was performed with treatment and control of the carriers until negative results were achieved. A consensus document was drawn up in the UHD with registered preventive measures and work systems were reviewed. Prevalence, cumulative incidence, colonization pressure (carrier ratio per day/total patients or experts per day) were calculated. A chi-square test was performed, as well as a Z test for the comparison ratio.

RESULTS

The nasal swabs of 54 acute and chronic patients on haemodialysis showed an initial carrier prevalence of 29.6%; cumulative incidence in patients of 42.6%. Nasal swabs of 48 professionals had a cumulative incidence of 39.5%. There was a parallel decrease in colonization pressure in patients and specialists. After five months A smear was performed 5 months later on 40 patients and 26 specialists, which showed no carriers among the patients, and one among the health professionals.

CONCLUSION

We detected a high number of MRSA carriers among patients and Health professionals from the Haemodialysis Unit. Screening and treatment measures were effective for the decolonization of this population. It is important to adopt long-term strategies for active surveillance for the rapid detection of alert situations.

Staphylococcal decolonisation: an effective strategy for prevention of infection?

Staphylococcus aureus decolonisation--treatment to eradicate staphylococcal carriage--is often considered as a measure to prevent S aureus infection. The most common approach to decolonisation has been intranasal application of mupirocin either alone or in combination with antiseptic soaps or systemic antimicrobial agents. Some data support the use of decolonisation in surgical patients colonised with S aureus, particularly in those undergoing cardiothoracic procedures. Although this intervention has been associated with low rates of postoperative S aureus infection, whether overall rates of infection are also decreased is unclear. Patients undergoing chronic haemodialysis or peritoneal dialysis might benefit from decolonisation, although repeated courses of treatment are needed, and the effects are modest. Eradication of meticillin-resistant S aureus (MRSA) carriage has generally been difficult, and the role of decolonisation as an MRSA infection control measure is uncertain. The efficacy of decolonisation of patients with community-associated MRSA has not been established, and the routine use of decolonisation of non-surgical patients is not supported by data.

The role of perioperative care in reducing rates of methicillin resistant Staphylococcus aureus

Methicillin resistant Staphylococcus aureus (MRSA) is defined as any strain of Staphylococcus aureus resistant to beta-lactam antibiotics, including the penicillins and cephalosporins. Over the past ten years the UK has seen a dramatic increase in MRSA prevalence in healthcare facilities and the community, with an estimated 30-50% of healthy adults thought to be colonised with MRSA. Surgical patients are among those at highest risk. With potential sequelae including septicaemia, septic shock, septic arthritis, osteomyelitis, meningitis, pneumonia or endocarditis, it is vital that all care facilities have up to date evidence-based guidelines to tackle this problem. The purpose of this review is to highlight the current evidence supporting some of the key perioperative measures which may be implemented in preventing MRSA.

A retrospective cohort study into acquisition of MRSA and associated risk factors after implementation of universal screening in Scottish hospitals

OBJECTIVE

To estimate the proportion of patients who acquire methicillin-resistant Staphylococcus aureus (MRSA) while in hospital and to identify risk factors associated with acquisition of MRSA.

DESIGN

Retrospective cohort study.

PATIENTS

Adult patients discharged from 36 general specialty wards of 2 Scottish hospitals that had implemented universal screening for MRSA on admission.

METHODS

Patients were screened for MRSA on discharge from hospital by using multisite body swabs that were tested by culture. Discharge screening results were linked to admission screening results. Genotyping was undertaken to identify newly acquired MRSA in MRSA-positive patients on admission.

RESULTS

Of the 5,155 patients screened for MRSA on discharge, 2.9% (95% confidence interval [CI], 2.43-3.34) were found to be positive. In the subcohort screened on both admission and discharge (n = 2,724), 1.3% of all patients acquired MRSA while in hospital (incidence rate, 2.1/1,000 hospital bed-days in this cohort [95% CI, 1.5-2.9]), while 1.3% remained MRSA positive throughout hospital stay. Three risk factors for acquisition of MRSA were identified: age above 64 years, self-reported renal failure, and self-reported presence of open wounds. On a population level, the prevalence of MRSA colonization did not differ between admission and discharge.

CONCLUSIONS

Cross-transmission of MRSA takes place in Scottish hospitals that have implemented universal screening for MRSA. This study reinforces the importance of infection prevention and control measures to prevent MRSA cross-transmission in hospitals; universal screening for MRSA on admission will in itself not be sufficient to reduce the number of MRSA colonizations and subsequent MRSA infections.

The longitudinal prevalence of MRSA in care home residents and the effectiveness of improving infection prevention knowledge and practice on colonisation using a stepped wedge study design

Objectives To determine the prevalence and health outcomes of meticillin-resistant Staphylococcus aureus (MRSA) colonisation in elderly care home residents. To measure the effectiveness of improving infection prevention knowledge and practice on MRSA prevalence. Setting Care homes for elderly residents in Leeds, UK. Participants Residents able to give informed consent. Design A controlled intervention study, using a stepped wedge design, comprising 65 homes divided into three groups. Baseline MRSA prevalence was determined by screening the nares of residents (n=2492). An intervention based upon staff education and training on hand hygiene was delivered at three different times according to group number. Scores for three assessment methods, an audit of hand hygiene facilities, staff hand hygiene observations and an educational questionnaire, were collected before and after the intervention. After each group of homes received the intervention, all participants were screened for MRSA nasal colonisation. In total, four surveys took place between November 2006 and February 2009. Results MRSA prevalence was 20%, 19%, 22% and 21% in each survey, respectively. There was a significant improvement in scores for all three assessment methods post-intervention (p≤0.001). The intervention was associated with a small but significant increase in MRSA prevalence (p=0.023). MRSA colonisation was associated with previous and subsequent MRSA infection but was not significantly associated with subsequent hospitalisation or mortality. Conclusions The intervention did not result in a decrease in the prevalence of MRSA colonisation in care home residents. Additional measures will be required to reduce endemic MRSA colonisation in care homes.

Is screening patients for antibiotic-resistant bacteria justified in the Indian context?

Infection with multi-antibiotic-resistant bacteria is a common clinical problem in India. In some countries and centres, screening patients to detect colonisation by these organisms is used to determine specific interventions such as decolonisation treatment, prophylactic antibiotics prior to surgical interventions or for selection of empirical antibiotic therapy, and to isolate patients so that transmission of these difficult to treat organisms to other patients could be prevented. In India, there is no national guideline or recommendation for screening patients for multi-drug-resistant (MDR) bacteria such as MRSA (methicillin-resistant Staphylococcus aureus), VRE (vancomycin-resistant enterococcus), ESBL (extended spectrum beta-lactamase) or MBL (metallo-beta-lactamase) producers. The present article discusses the relevance of screening patients for multi-antibiotic-resistant bacteria in the Indian context. Literature has been reviewed about antibiotic resistance in India, screening methodology, economic debate about screening. The percentages of strains from various hospitals in India which were reported to be MRSA was between 8 and 71%, those for ESBL between 19 and 60% and carbapenem-resistant Gram-negative bacilli between 5.3 and 59%. There exists culture-based technology for the detection of these resistant organisms from patient samples. For some pathogens, such as MRSA and VRE Polymerase chain reaction-based tests are also becoming available. Screening for MDR bacteria is an option which may be used after appraisal of the resources available, and after exploring possibility of implementing the interventions that may be required after a positive screening test result.

Clinical effectiveness of rapid tests for methicillin resistant Staphylococcus aureus (MRSA) in hospitalized patients: a systematic review

Background

Methicillin resistant Staphylococcus aureus (MRSA) are often resistant to multiple classes of antibiotics. The research objectives of this systematic review were to evaluate the clinical effectiveness of polymerase chain reaction (PCR) versus chromogenic agar for MRSA screening, and PCR versus no screening for several clinical outcomes, including MRSA colonization and infection rates.

Methods

An electronic literature search was conducted on studies evaluating polymerase chain reaction techniques and methicillin (also spelled meticillin) resistant Staphylococcus aureus that were published from 1993 onwards using Medline, Medline In-Process & Other Non-Indexed Citations, BIOSIS Previews, and EMBASE. Due to the presence of heterogeneity in the selected studies, the clinical findings of individual studies were described.

Results

Nine studies that compared screening for MRSA using PCR versus screening using chromogenic agar in a hospital setting, and two studies that compared screening using PCR with no or targeted screening were identified. Some studies found lower MRSA colonization and acquisition, infection, and transmission rates in screening with PCR versus screening with chromogenic agar, and the turnaround time for screening test results was lower for PCR. One study reported a lower number of unnecessary isolation days with screening using PCR versus screening with chromogenic agar, but the proportion of patients isolated was similar between both groups. The turnaround time for test results and number of isolation days were lower for PCR versus chromogenic agar for MRSA screening.

Conclusions

The use of PCR for MRSA screening demonstrated a lower turnaround time and number of isolation days compared with chromogenic agar. Given the mixed quality and number of studies (11 studies), gaps remain in the published literature and the evidence remains insufficient. In addition to screening, factors such as the number of contacts between healthcare workers and patients, number of patients attended by one healthcare worker per day, probability of colonization among healthcare workers, and MRSA status of hospital shared equipment and hospital environment must be considered to control the transmission of MRSA in a hospital setting.

Infection control strategies for preventing the transmission of meticillin-resistant Staphylococcus aureus (MRSA) in nursing homes for older people

BACKGROUND

Nursing homes for older people provide an environment likely to promote the acquisition and spread of meticillin-resistant Staphylococcus aureus (MRSA), putting residents at increased risk of colonisation and infection. It is recognised that infection prevention and control strategies are important in preventing and controlling MRSA transmission.

OBJECTIVES

To determine the effects of infection prevention and control strategies for preventing the transmission of MRSA in nursing homes for older people.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2011, Issue 2), the Cochrane Wounds Group Specialised Register (searched May 27th, 2011). We also searched Ovid MEDLINE (from 1950 to April Week 2 2011), OVID MEDLINE (In-process and Other Non-Indexed Citations, April 26th 2011) Ovid EMBASE (1980 to 2011 Week 16), EBSCO CINAHL (1982 to April 21st 2011), DARE (1992 to 2011, week 16), Web of Science (1981 to May 2011), and the Health Technology Assessment (HTA) website (1988 to May 2011). Research in progress was sought through Current Clinical Trials (www.controlled-trials.com), Medical Research Council Research portfolio, and HSRPRoj (current USA projects).

SELECTION CRITERIA

All randomised and controlled clinical trials, controlled before and after studies and interrupted time series studies of infection prevention and control interventions in nursing homes for older people were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the results of the searches. Another review author appraised identified papers and undertook data extraction which was checked by a second review author.

MAIN RESULTS

For this second update only one study was identified, therefore it was not possible to undertake a meta-analysis. A cluster randomised controlled trial in 32 nursing homes evaluated the effect of an infection control education and training programme on MRSA prevalence. The primary outcome was MRSA prevalence in residents and staff, and a change in infection control audit scores which measured adherence to infection control standards. At the end of the 12 month study, there was no change in MRSA prevalence between intervention and control sites, while mean infection control audit scores were significantly higher in the intervention homes compared with control homes.

AUTHORS' CONCLUSIONS

There is a lack of research evaluating the effects on MRSA transmission of infection prevention and control strategies in nursing homes. Rigorous studies should be conducted in nursing homes, to test interventions that have been specifically designed for this unique environment.

MRSA prevention strategies and current guidelines

We review prevention strategies to minimise the risk of MRSA soft tissue and bone infections, which can be devastating for the patient and costly for the healthcare provider. Department of Health (England) policy is that screening for emergency admissions will be mandatory from 2011, in addition to existent elective admission screening. Rapid screening technology has not been shown to be cost-effective, meaning that there will be a lag time between admission and the patient's MRSA status being known. Thus, standard infection control policies regarding isolation of high-risk patients will remain, with a continuing focus on MRSA decolonisation, aimed at minimising the risks of auto-infection and transmission to other patients. Antimicrobial prescribing policies should be designed to take into account the local burden of resistant organisms, but also minimise unnecessary antibiotic use. There is an increasing realisation that reducing the use of fluoroquinolones and third-generation cephalosporins (which have been associated with increased carriage of MRSA) in patient populations where MRSA is prevalent can be a useful control measure. Prevention of orthopaedic infections clearly involves general operating theatre protocols, such as suitable antiseptic skin preparation, and additional measures including the use of laminar airflow. Antibiotic prophylaxis is adjusted in patients known to have MRSA to include a glycopeptide, and local guidelines may adopt such regimens for all patients due to the burden of MRSA in the local patient population. A future development that may have an effect on practice is the development of a Staphylococcus aureus vaccine, which has been shown to be cost-effective in a computer-modelled evaluation.

Screening, isolation, and decolonisation strategies in the control of meticillin resistant Staphylococcus aureus in intensive care units: cost effectiveness evaluation

OBJECTIVE

To assess the cost effectiveness of screening, isolation, and decolonisation strategies in the control of meticillin resistant Staphylococcus aureus (MRSA) in intensive care units.

DESIGN

Economic evaluation based on a dynamic transmission model.

SETTING

England and Wales. Population Theoretical population of patients on an intensive care unit.

MAIN OUTCOME MEASURES

Infections, deaths, costs, quality adjusted life years (QALYs), incremental cost effectiveness ratios for alternative strategies, and net monetary benefits.

RESULTS

All decolonisation strategies improved health outcomes and reduced costs. Although universal decolonisation (regardless of MRSA status) was the most cost effective in the short term, strategies using screening to target MRSA carriers may be preferred owing to the reduced risk of selecting for resistance. Among such targeted strategies, universal admission and weekly screening with polymerase chain reaction coupled with decolonisation using nasal mupirocin was the most cost effective. This finding was robust to the size of intensive care units, prevalence of MRSA on admission, proportion of patients classified as high risk, and precise value of willingness to pay for health benefits. All strategies using isolation but not decolonisation improved health outcomes but costs were increased. When the prevalence of MRSA on admission to the intensive care unit was 5% and the willingness to pay per QALY gained was between £20,000 (€23,000; $32,000) and £30,000, the best such strategy was to isolate only those patients at high risk of carrying MRSA (either pre-emptively or after identification by admission and weekly screening for MRSA using chromogenic agar). Universal admission and weekly screening using polymerase chain reaction based detection of MRSA coupled with isolation was unlikely to be cost effective unless prevalence was high (10% of patients colonised with MRSA on admission).

CONCLUSIONS

MRSA control strategies that use decolonisation are likely to be cost saving in an intensive care unit setting provided resistance is lacking, and combining universal screening using polymerase chain reaction with decolonisation is likely to represent good value for money if untargeted decolonisation is considered unacceptable. In intensive care units where decolonisation is not implemented, evidence is insufficient to support universal screening for MRSA outside high prevalence settings.

Community-associated meticillin-resistant Staphylococcus aureus strains as a cause of healthcare-associated infection

Community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) was first noticed as a cause of infection in community-based individuals without healthcare contact. As the global epidemic of CA-MRSA has continued, CA-MRSA strain types have begun to emerge as a cause of healthcare-associated infections (HAIs) and hospital outbreaks have occurred worldwide. In areas where CA-MRSA clones have become established with high prevalence, for example USA300 (ST8-IV) in the USA, CA-MRSA are beginning to supplant or overtake traditional healthcare-associated MRSA strains as causes of HAI. The emergence of CA-MRSA as a cause of HAI puts a wider group of hospitalised patients, healthcare workers and their community contacts potentially at risk of MRSA infection. It also exposes CA-MRSA strains to the selective pressure of antibiotic use in hospitals, potentially resulting in increased antibiotic resistance, challenges traditional definitions of CA-MRSA and hampers control efforts due to the constant re-introduction of MRSA from an emerging community reservoir. There is thus an urgent need to clarify the definitions, prevalence and epidemiology of CA-MRSA and to develop systems for the identification and control of these organisms in the community, in hospitals and other healthcare facilities, and at the community-hospital interface.

Studying the transmission dynamics of meticillin-resistant Staphylococcus aureus in Hong Kong using spa typing

This study investigated the transmission dynamics of meticillin-resistant Staphylococcus aureus (MRSA) in a tertiary referral surgical unit with 300 beds. All adult patients were actively screened for MRSA by culture at hospital admission and twice weekly thereafter during hospitalisation from 1 October to 31 December 2008. The colonisation pressure per 1000 patient-days and the incidence density of nosocomial MRSA transmission per 1000 colonisation-days were calculated for the different spa types of MRSA. In total, 6619 nasal swabs were obtained from 2289 patients. One-hundred and forty-eight (7%) patients had MRSA in nasal swabs at admission screening, of which 68/148 (46%) were residents of elderly care homes. Fifty-two of 2141 (2%) patients had conversion of nasal MRSA carriage status from negative to positive during hospitalisation. Among the 200 patients with MRSA, spa types t1081 and t037 were found in 99 (50%) and 30 (15%) patients, respectively. The colonisation pressure per 1000 patient-days was 40.9 for t0181, 22.2 for t037 and 26.3 for the less common spa types. The incidence densities of nosocomial MRSA transmission per 1000 colonisation-days were significantly higher for t1081 (28.5 vs 4.0, P<0.01) and t037 (21.5 vs 4.0, P=0.03) compared with the less common spa types. Proactive screening of MRSA in patients from elderly care homes and targeted isolation of these patients, especially those carrying spa types with high transmissibility, are important for the control of MRSA in hospitals.