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

Universal screening for meticillin-resistant Staphylococcus aureus: interim results from the NHS Scotland pathfinder project

Following recommendations from a Health Technology Assessment (HTA), a prospective cohort study of meticillin-resistant Staphylococcus aureus (MRSA) screening of all admissions (N=29 690) to six acute hospitals in three regions in Scotland indicated that 7.5% of patients were colonised on admission to hospital. Factors associated with colonisation included re-admission, specialty of admission (highest in nephrology, care of the elderly, dermatology and vascular surgery), increasing age, and the source of admission (care home or other hospital). Three percent of all those who were identified as colonised developed hospital-associated MRSA infection, compared with only 0.1% of those not colonised. Specialties with a high rate of colonisation on admission also had higher rates of MRSA infection. Very few patients refused screening (11 patients, 0.03%) or had treatment deferred (14 patients, 0.05%). Several organisational issues were identified, including difficulties in achieving complete uptake of screening (88%) or decolonisation (41%); the latter was largely due to short duration of stay and turnaround time for test results. Patient movement resulted in a decision to decolonise all positive patients rather than just those in high risk specialties as proposed by the HTA. Issues also included a lack of isolation facilities to manage patients with MRSA. The study raises significant concerns about the contribution of decolonisation to reducing risks in hospital due to short duration of stay, and reinforces the central role of infection control precautions. Further study is required before the HTA model can be re-run and conclusions redrawn on the cost and clinical effectiveness of universal MRSA screening.

A prospective study of the impact of colonization following hospital admission by glycopeptide-resistant Enterococci on mortality during a hospital outbreak

BACKGROUND

This study was designed to investigate the impact on mortality of colonization by glycopeptide-resistant Enterococci (GRE) during hospitalization.

METHODS

Between 2004 and 2006, a hospital in Nancy, France, was subject to a GRE van A outbreak. Some 113 patients who had acquired GRE after hospital admission were matched with 113 controls. Basic demographic data, such as sex, age, principal pathology, history of surgery, and presence of associated pathology, were obtained for each case and control. Information on whether or not the case subject was still alive was obtained by searching the hospital mortality database and the civil death register and by phoning the patient's home. Statistical analysis used the Cox proportional hazards model for calculating survival function with SPSS software version 9.1 (SPSS Inc., Chicago, IL).

RESULTS

The mean age was 71.2 in the GRE+ group and 70.8 in the control group (P = .80). There was a significant difference between the groups for severity status health (P = .035). The mortality rate was 30.1% in the case group and 19.5% in the control group. Single predictor variable analysis showed a hazard ratio of death in the case group of 4.61 (95% confidence interval [CI]: 2.58-8.28], P = 2 x 10(-7)). The final Cox regression model with multiple predictor variables showed that only GRE presence (OR, 1.63 [95% CI: 1.04-2.57], P = .035) and severity of comorbidity (P = .013) were independently significant predictors of mortality.

CONCLUSION

This study shows that the GRE acquisition has a poor prognosis and that this is independent of the other prognostic factors such as age and severity of underlying disease. Survival in GRE+ patients was significantly shorter.

Clinical application of real-time PCR to screening critically ill and emergency-care surgical patients for methicillin-resistant Staphylococcus aureus: a quantitative analytical study

The clinical utility of real-time PCR screening assays for methicillin (methicillin)-resistant Staphylococcus aureus (MRSA) colonization is constrained by the predictive values of their results: as MRSA prevalence falls, the assay's positive predictive value (PPV) drops, and a rising proportion of positive PCR assays will not be confirmed by culture. We provide a quantitative analysis of universal PCR screening of critical care and emergency surgical patients using the BD GeneOhm MRSA PCR system, involving 3,294 assays over six months. A total of 248 PCR assays (7.7%) were positive; however, 88 failed to be confirmed by culture, giving a PPV of 65%. Multivariate analysis was performed to compare PCR-positive culture-positive (P+C+) and PCR-positive culture-negative (P+C-) assays. P+C- results were positively associated with a history of methicillin-sensitive Staphylococcus aureus infection or colonization (odds ratio [OR], 3.15; 95% confidence interval [CI], 1.32 to 7.54) and high PCR thresholds of signal intensity, indicative of a low concentration of target DNA (OR, 1.19 per cycle; 95% CI, 1.11 to 1.26). P+C- results were negatively associated with a history of MRSA infection or colonization (OR, 0.19; 95% CI, 0.09 to 0.42) and male sex (OR, 0.40; 95% CI, 0.20 to 0.81). P+C+ patients were significantly more likely to have subsequent positive MRSA culture assays and microbiological evidence of clinical MRSA infection. The risk of subsequent MRSA infection in P+C- patients was not significantly different from that in case-matched PCR-negative controls. We conclude that, given the low PPV and poor correlation between a PCR-positive assay and the clinical outcome, it would be prudent to await culture confirmation before altering infection control measures on the basis of a positive PCR result.

UK healthcare workers' knowledge of meticillin-resistant Staphylococcus aureus practice guidelines; a questionnaire study

Effective infection control practice requires knowledge of and adherence to contemporary infection control guidelines. Utilising a novel questionnaire tool, we evaluated knowledge of recently published guidelines on meticillin-resistant Staphylococcus aureus (MRSA) precautions in a number of relevant healthcare worker (HCW) populations. The questionnaire was developed from national UK MRSA practice guidelines and consisted of 10 'true or false' statements. The questionnaire was utilised to assess knowledge in 293 participants from HCW and control populations. The participants included 188 doctors attending the British Medical Association's Annual Representatives Meeting, 52 trainee surgeons attending the Association of Surgeons in Training annual conference, 30 members of a non-clinical control population and 23 infection control nurses (ICNs). The mean (SD) score for knowledge levels obtained from doctors was 6.6 (1.68), for non-clinical control population was 4.7 (1.8) and for ICNs, 8.4 (1.12). There were significant differences in knowledge levels between different population groups (P<0.001), UK employment region of the participant (P=0.01) and the doctors' medical specialty (P=0.02). Career seniority and gender of the participant were not significantly associated with differences in levels of knowledge. This questionnaire study evaluates a novel discriminatory questionnaire tool which differentiates knowledge levels of MRSA practice guidelines among a non-clinical population, HCWs and specialist infection control staff, thus providing a means for the rapid assessment of MRSA educational interventions. We identify demographics within HCW target populations which are associated with low levels of such knowledge. Consideration towards revising current HCW educational programmes to improve knowledge and best practice in MRSA prevention is required.

Using students on a short educational placement with an infection prevention team to assist in implementation of universal MRSA screening: achieving educational outcomes and identifying policy compliance

his article describes how an infection prevention team (IPT) used an interprofessional group of student healthcare professionals on a short placement to audit meticillin resistant Staphylococcus aureus (MRSA) screening policy compliance in the run-up to implementation of a new national MRSA screening target in England. It highlights the resource required by the IPT to support the group, the process of the audit and results, the experience of the students, and the policy and learning outcomes from both the audit and the experience of the placement. Other teams may find a similar approach beneficial for their organisations.

An investigation of the risk factors for infection with methicillin-resistant Staphylococcus aureus among patients in a neonatal intensive care unit

BACKGROUND

The aims of this study were to investigate the risk factors of methicillin-resistant Staphylococcus aureus (MRSA) infection among infants to establish effective infection control measures for neonatal intensive care unit (NICU).

METHODS

Data were prospectively collected from 961 infants hospitalized in a teaching hospital in Japan, from July 2002 through December 2005.

RESULTS

Among all infants, 28 (2.9%) developed MRSA infections. Multivariate logistic regression analyses demonstrated the risk factors for developing MRSA infections to include a low birth weight (odds ratio [OR], 0.91; 95% confidence interval [CI]: 0.93-0.99), the presence of eye mucous (OR, 6.78; 95% CI: 2.87-16.01), the practice of kangaroo mother care (OR, 3.82; 95% CI: 1.11-13.13), and the MRSA colonization rate (OR, 11.12; 95% CI: 1.32-93.89).

CONCLUSION

The risk factors for developing a MRSA infection among infants in NICU were a low birth weight, the presence of eye mucous, the practice of kangaroo mother care, and a high MRSA colonization rate. Therefore, extra attention should be given to infants in high-risk groups demonstrating a low birth weight and the presence of eye mucous and who have undergone kangaroo mother care. As a result, the cohort isolation of infants with MRSA may therefore be an effective strategy to prevent MRSA infections.

Molecular surveillance and population structure analysis of methicillin-susceptible and methicillin-resistant Staphylococcus aureus in high-risk wards

In this study we report the results of analysis of 253 isolates of Staphylococcus aureus (132 methicillin [meticillin]-resistant S. aureus [MRSA] isolates and 121 methicillin-susceptible S. aureus [MSSA] isolates) from 209 patients admitted to 18 high-risk wards of six hospitals located in Florence, Italy, over an 8-month period during which a program of epidemiological surveillance of hospital-acquired infections was conducted. The majority (69%) of the 87 reported S. aureus infections were caused by MRSA. No outbreak events have been reported. All the isolates were typed by amplified fragment length polymorphism (AFLP), and AFLP profiles were analyzed in order to define similarity groups. The discriminatory power of AFLP is very high with MSSA (Simpson index of diversity [D], 95.9%), whereas its resolution capability with MRSA (D, 44.7%) is hampered by the well-known high clonality of these populations (the main MRSA group accounted for 74% of the MRSA isolates). Combining AFLP, improved by visual inspection of polymorphisms, with multiplex PCR greatly increases MRSA resolution (D, 85.5%), resolving the MRSA population to a level that is one of the highest reported in the literature. Widespread and sporadic clones of MSSA and MRSA were identified, and their diffusion in the different hospitals and wards over the surveillance period was studied. The understanding of MSSA and MRSA population structures should be the starting point for the design of a more rational surveillance program for S. aureus species, maximizing benefits and reducing the cost of infection control strategies.

Detecção do gene mecA em estafilococos coagulase negativa resistentes à oxacilina isolados da saliva de profissionais da enfermagem

Estafilococos coagulase negativa estão frequentemente associados às infecções nosocomiais e os profissionais da saúde podem ser reservatório e dissemina-los no hospital e comunidade. O objetivo desse estudo foi identificar espécies de estafilococos coagulase negativa isolados da saliva de profissionais da enfermagem, determinar o perfil de resistência e detectar o gene mecA. Foram selecionados 100 estafilococos coagulase negativa, sendo 41 identificados como Staphylococcus epidermidis, 25 Staphylococcus saprophyticus, 18 Staphylococcus haemolyticus, 8 Staphylococcus cohnii, 4 Staphylococcus lugdunenses, 3 Staphylococcus capitis, e 1 Staphylococcus Simulans. Desses, 32% apresentaram resistência à oxacilina, 84,4% à mupirocina, 32% à cefoxitina, e todos sensíveis a vancomicina. Dos estafilococos coagulase negativa resistentes à oxacilina, 93,7% desenvolveram-se no agar oxacilina (6µg/ml) e o gene mecA foi detectado em 75%. Os resultados sinalizam que maiores investimentos devem ser direcionados a identificação das espécies de estafilococos coagulase negativa nas instituições de saúde e na comunidade.

Reviewing the efficacy of infection control isolation

As part of a package of measures aimed at preventing cross-infection the isolation of patients in single rooms or through cohort nursing is a well-documented policy. However, the evidence base for an isolation policy is unclear it can cause logistical problems through inadequate resources and may result in physical, psychological and social harm to patients. Notwithstanding these problems, isolation can be said to have a practical utility in that it may impact on a nurses behaviour as they enact compliance as part of their infection control duties. It is nevertheless important for policymakers to note that it is not the location of the patient per se that is of primary importance in the transmission of contact spread organisms, but the behaviour of staff within the isolated environment.

The cost of resistance: incremental cost of methicillin-resistant Staphylococcus aureus (MRSA) in German hospitals

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant problem in many healthcare systems. In Germany, few data are available on its economic consequences and, so far, no study has been performed using a large sample of real-life data from several hospitals. We present a retrospective matched-pairs analysis of mortality, length of stay, and cost of MRSA patients based mainly on routine administrative data from 11 German hospitals. Our results show that MRSA patients stay in hospital 11 days longer, exhibit 7% higher mortality, are 7% more likely to undergo mechanical ventilation, and cause significantly higher total costs (<euro> 8,198).

Prevalence of methicillin-resistant Staphylococcus aureus colonization in residents and staff in nursing homes in Northern Ireland

OBJECTIVES

To determine the prevalence of, and factors associated with, methicillin-resistant Staphylococcus aureus (MRSA) colonization in residents and staff in nursing homes in one geographically defined health administration area of Northern Ireland.

DESIGN

Point prevalence study.

SETTING

Nursing homes.

PARTICIPANTS

Residents and staff in nursing homes.

MEASUREMENTS

Nasal swabs were taken from all consenting residents and staff. If relevant, residents also provided urine samples, and swabs were taken from wounds and indwelling devices.

RESULTS

A total of 1,111 residents (66% of all residents) and 553 staff (86% of available staff) in 45 nursing homes participated. The combined prevalence rate of MRSA in the resident population was 23.3% (95% confidence interval (CI)=18.8-27.7%) and 7.5% in staff (95% CI=5.1-9.9%). Residents who lived in nursing homes that were part of a chain were more likely to be colonized with MRSA (odds ratio (OR)=1.91, 95% CI=1.21-3.02) than those living in independently owned facilities. Residents were also more likely to be colonized if they lived in homes in which more than 12.5% of all screened healthcare staff (care assistants and nurses) were colonized with MRSA (OR=2.46, 95% CI=1.41-4.29) or if they lived in homes in which more than 15% of care assistants were colonized with MRSA (OR=2.64, 95% CI=1.58-4.42).

CONCLUSION

The findings suggest that there is substantial colonization of MRSA in nursing home residents and staff in this one administrative health area. Implementation of infection control strategies should be given high priority in nursing homes.

Nasal decolonization of Staphylococcus aureus with mupirocin: strengths, weaknesses and future prospects

Staphylococcus aureus in the nose is a risk factor for endogenous staphylococcal infection. UK guidelines recommend the use of mupirocin for nasal decolonization in certain groups of patients colonized with methicillin-resistant S. aureus (MRSA). Mupirocin is effective at removing S. aureus from the nose over a few weeks, but relapses are common within several months. There are only a few prospective randomized clinical trials that have been completed with sufficient patients, but those that have been reported suggest that clearance of S. aureus from the nose is beneficial in some patient groups for the reduction in the incidence of nosocomial infections. There is no convincing evidence that mupirocin treatment reduces the incidence of surgical site infection. New antibiotics are needed to decolonize the nose because bacterial resistance to mupirocin is rising, and so it will become less effective. Furthermore, a more bactericidal antibiotic than mupirocin is needed, on the grounds that it might reduce the relapse rate, and so clear the patient of MRSA for a longer period of time than mupirocin.

Implementing the MRSA recommendations made by the Commission for Hospital Hygiene and Infection Prevention (KRINKO) of 1999 - current considerations by the DGKH Management Board

In Germany, recommendations on dealing with patients who are colonised with methicillin-resistant S. aureus (MRSA) for the inpatient sector have been published in 1999 by the Commission for Hospital Hygiene and Infection Prevention (KRINKO). Some challenges arise with regard to the practical implementation of the KRINKO recommendations. These challenges do not principally question the benefit of the recommendations but have come into criticism from users. In this commentary the German Society for Hospital Hygiene (DGKH) discusses some controversial issues and adds suggestions for unresolved problems regarding the infection control management of MRSA in healthcare settings.

Controlling MRSA in head and neck cancer patients: what works?

OBJECTIVE

We aimed to determine any beneficial effect from targeted surveillance, cohort nursing, and restricted health care worker access in controlling MRSA infection in patients undergoing surgery for head and neck cancer.

STUDY DESIGN

Historical cohort study.

SUBJECTS AND METHODS

In phase 1 data were gathered on MRSA-positive cases admitted from February 1, 2006 to February 28, 2007. In phase 2, from July 1, 2007 to January 31, 2008, eligible patients underwent screening swabs, cohort nursing, and restricted access.

RESULTS

In the first phase, 24 patients developed MRSA infection out of a total of 84 eligible admissions. There were 31 eligible admissions during phase 2. None of them had known risk factors for MRSA as per Scottish Infection Standards and Strategy Group (SISS) guidelines. All screened patients were noncarriers of MRSA. Three patients out of this group subsequently developed MRSA during their hospital stay. There was a statistically significant drop in MRSA to 9.6 percent (3/31) during this phase compared to 28.5 percent (24/84) in phase 1.

CONCLUSION

Head and neck cancer patients are at high risk of acquiring MRSA infection. Their targeted surveillance is unlikely to influence their MRSA infection rate. However, cohort nursing with restricted health care worker access may help control MRSA infection in them.

Fact or infection: do surgical trainees know enough about infection control?

INTRODUCTION

There exists a high level of non-compliance with basic infection control measures by medical staff. One explanation may be a lack of familiarity with contemporary infection control guidelines. As surgical trainees represent a key group of stakeholders responsible for the delivery of recommended infection control practice, we assessed knowledge of infection control guidelines amongst current UK surgical trainees.

MATERIALS AND METHODS

Without warning, during the annual meeting of the UK Association of Surgeons in Training (ASiT), participating surgical trainees were asked to complete a questionnaire examining their basic knowledge of infection control and methicillin-resistant Staphylococcus aureus (MRSA) based on recently published guidelines.

RESULTS

A total of 52 trainees (13 higher surgical trainees [HSTs]; 39 basic surgical trainees [BSTs]) returned completed questionnaires in the study. BSTs demonstrated a higher level of knowledge of infection control, outperforming the HSTs in 7 out of 11 questions. Of surgical trainees, 61.5% were misinformed regarding the prevalence of MRSA blood-stream infections and 69% were unaware of policies for transfer of MRSA-positive patients. Analysis revealed areas of concern in regards to an adequate general level of knowledge of infection control in surgical trainees, particularly in some key areas.

CONCLUSIONS

To ensure patient safety and reduce hospital-acquired infections, it is vital that focused, co-ordinated programmes of education, in this rapidly changing field, are prioritised and formalised into surgical training, selection and assessment.

Prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus and its antibiotic susceptibility pattern in healthcare workers at Namazi Hospital, Shiraz, Iran

OBJECTIVE

The aim of this study was to determine the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers (HCWs) at Namazi Hospital, Shiraz, Iran.

METHODS

This cross-sectional study was conducted from July to November 2006. Nasal swabs were taken from 600 randomly selected HCWs. The isolates were identified as S. aureus based on morphology, Gram stain, catalase test, coagulase test, and mannitol salt agar fermentation. To analyze sensitivity patterns of MRSA strains more precisely, minimum inhibitory concentrations (MICs) of antibiotics were determined by the E-test method. All methicillin-resistant isolates were examined for the existence of the mecA gene by total DNA extraction and PCR.

RESULTS

The prevalence of nasal carriage of methicillin-sensitive S. aureus (MSSA) was 25.7% and of MRSA was 5.3%, with the highest nasal carriage of MRSA in surgical wards and the emergency department. There was no significant difference between the sexes (p=0.247), age (p=0.817), and years of healthcare service (p=0.15) with regard to the nasal carriage of MRSA and MSSA. In the univariate analysis, a statistically significant difference was only found for occupation (p=0.032) between the carriage of MSSA and MRSA. In the multivariate analysis, the occupation 'nurse' was independently associated with MRSA carriage (p=0.012, odds ratio 3.6, 95% confidence interval 1.3-9.7). The highest resistance rate for both gentamicin and clindamycin (69%) was noted among the MRSA strains. None of the MRSA strains were resistant to mupirocin, linezolid, fusidic acid, or vancomycin. The existence of the mecA gene in all 32 methicillin-resistant isolates was observed by PCR.

CONCLUSIONS

This study revealed the prevalence of nasal carriage of S. aureus strains among HCWs to be lower than that found in other studies from Iran. The antibiotic susceptibility patterns also differed, perhaps as a result of the excessive use of antibiotics at our hospital. Only the occupation of nurse was an independent risk factor for MRSA carriage.

Are glycopeptides still appropriate and convenient for empiric use?

The glycopeptides vancomycin and teicoplanin are widely used, and indeed recommended for, the treatment of severe or resistant Gram-positive infections. Therapeutic drug monitoring is widely used for vancomycin but less commonly for teicoplanin, and remains controversial. We report the cost savings of a formulary decision to replace teicoplanin with daptomycin for the empiric treatment of complicated skin and soft tissue infections (CSSTIs), staphylococcal bacteraemia and hospital-acquired Gram-positive sepsis. In the Intensive Therapy Unit (ITU) we optimised treatment of serious Gram-positive infections by substituting teicoplanin with vancomycin administered by continuous infusion. Costs were calculated using British National Formulary (BNF) prices and costs for therapeutic drug monitoring. Daptomycin (350 mg/d) use was associated with a cost saving per 7 days of treatment of 86 pounds and vancomycin with 51 pounds (4 g/d) to 276 pounds (2 g/d) compared to the 600 mg teicoplanin dose. Our own formulary re-positioning of glyco/lipopeptides, i.e. the preferential use of vancomycin in the ITU and substitution of teicoplanin with daptomycin, is cost-effective and provides better therapeutic alternatives. Continuous vancomycin infusion in the ITU setting guarantees optimal dosing for severely ill patients. Daptomycin use on surgical and medical wards, apart from being marginally cheaper than teicoplanin, guarantees optimal dosing without the need for drug monitoring.

A prevalence screen of MRSA nasal colonisation amongst UK doctors in a non-clinical environment

Screening for methicillin-resistant Staphylococcus aureus (MRSA) carriage in healthcare workers (HCWs) is both contentious and confounded by a lack of knowledge of background prevalence rates. This study examines prevalence of nasal MRSA carriage amongst a spectrum of medical professionals in a non-clinical environment. Medical conference attendees volunteered for screening for nasal MRSA carriage, and anonymised demographic data and attitudes towards screening were recorded. Two hundred sixty volunteers participated. One hundred seventy-three participants (67%) were from the British Medical Association's Annual Representatives Meeting, and 87 participants (33%) were attending the Association of Surgeons in Training conference. Six (2%) participants were positive for MRSA nasal carriage (BMA = 1%, ASIT = 5%; p = 0.099). Participants from a surgical specialty (4.8%) were more likely to be MRSA positive (p = 0.039). All positive samples came from male participants (p = 0.182). However, there was no significant association with gender, seniority or country of employment and MRSA status. Routine screening for MRSA was supported by 63% of participants in HCWs; 36% had previously undergone such screening. MRSA nasal carriage rates within this cross-sectional study are lower than studies reporting carriage rates in HCWs within the clinical environment. Further research is required to examine the relationship between MRSA nasal colonisation status of a HCW and subsequent MRSA infection in patients.

Recent advances in the microbiology of respiratory tract infection in cystic fibrosis

INTRODUCTION

Infection is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). Research on CF infection has highlighted differences from other respiratory infections--both in the range and the nature of the organisms--especially in chronic infection. This is a rapidly advancing field of microbiology and is bringing insights into the complexity and adaptations of bacteria causing chronic infection in the respiratory tract.

AREAS OF AGREEMENT AND CONTROVERSY

The epidemiology of some infections in CF has changed, with reduction in spread of Burkholderia cenocepacia following patient segregation. Conversely, epidemic strains of Pseudomonas aeruginosa have emerged, which spread between patients; previously, most P. aeruginosa strains were patient-specific. Studies on hypermutators, quorum sensing, biofilm growth and the development of molecular identification have shed light on pathogenicity, microbial adaptation to the host and complexity of infection in CF. Non-tuberculous mycobacteria are emerging pathogens in CF; however, there is much to learn about pathogenicity and treatment of these infections. Species of aerobic and anaerobic bacteria, more commonly encountered in the upper tract, are found in significant numbers in CF sputum. The significance of this is however under debate. Finally, although the clinical relevance of conventional antibiotic susceptibility testing for chronic CF pathogens has been questioned, there are no clear alternatives.

EMERGING AREAS FOR DEVELOPING RESEARCH

Much has been learnt about pathogenicity, evolution of CF pathogens and development of antibiotic resistance. The need is to focus on clinical relevance of these observations to improve diagnosis, prevention and treatment of CF infection.

Reducing the risk: the use of placebo respiratory equipment in clinical practice

Placebo respiratory devices, such as inhalers, large volume spacers and peak flow meters provide reli able methods of teaching patients effective drug able methods of teaching patients effective drug delivery techniques and monitoring compliance and treatment progress. Concern has been raised that using such demonstration devices on more than one person may expose patients to the risk of cross-infection with pathogenic organisms. The lack of regulation and guidance on the use and decontamination of placebo devices prompted us to complete a risk assessment, examining the likelihood and consequence of acquisition of pathogens and resultant illness in our respiratory patient group.

Prevalence of methicillin-resistant and methicillin-susceptible s. aureus in the saliva of health professionals

INTRODUCTION

S. aureus is one of the main agents of nosocomial infection and is sometimes difficult to treat with currently available active antimicrobials.

PURPOSE

To analyze the prevalence of methicillin-susceptible S.aureus (MSSA) and methicillin-resistant S. aureus (MRSA) as well as the MRSA antimicrobial susceptibility profile isolated in the saliva of health professionals at a large public education hospital.

MATERIALS AND METHODS

The project was approved by the research and ethics committee of the institution under study. Three samples of saliva from 340 health professionals were collected. The saliva analysis used to identify S. aureus was based on mannitol fermentation tests, catalase production, coagulase, DNAse, and lecithinase. In order to detect MRSA, samples were submitted to the disk diffusion test and the oxacillin agar screening test. In order to identify the minimum inhibitory concentration, the Etest technique was used.

RESULTS

The prevalence of MSSA was 43.5% (148/340), and MRSA was 4.1% (14/340). MRSA detected by the diffusion disk test, was 100% resistant to penicillin and oxacillin, 92.9% resistant to erythromycin, 57.1% resistant to clindamycin, 42.9% resistant to ciprofloxacin and 57.1% resistant to cefoxetin.

CONCLUSION

This subject is important for both the education of health professionals and for preventative measures. Standard and contact-precautions should be employed in professional practice.

Bloodstream infections in haematology: risks and new challenges for prevention

Bloodstream infections are an important cause of morbidity and mortality in the haematology population, and may contribute to delayed administration of chemotherapy, increased length of hospitalisation, and increased healthcare expenditure. For gram-positive, gram-negative, anaerobic and fungal infections, specific risk factors are recognised. Unique host and environmental factors contributing to pathogenesis are acknowledged in this population. Trends in spectrum and antimicrobial susceptibility of pathogens are examined, and potential contributing factors are discussed. These include the widespread use of empiric antimicrobial therapy, increasingly intensive chemotherapeutic regimens, frequent use of central venous catheters, and local infection control practices. In addition, the risks and benefits of prophylaxis, and spectrum of endemic flora are identified as relevant factors within individual centres. Finally, challenges are presented regarding prevention, early detection, surveillance and prophylaxis. To reduce the rate and impact of bloodstream infections multifaceted and customised strategies are required within individual haematology units.

The role of healthcare personnel in the maintenance and spread of methicillin-resistant Staphylococcus aureus

Healthcare workers may acquire methicillin-resistant Staphylococcus aureus (MRSA) from patients, both hospital and home environments, other healthcare workers, family and public acquaintances, and pets. There is a consensus of case reports and series which now strongly support the role for MRSA-carrying healthcare personnel to serve as a reservoir and as a vehicle of spread within healthcare settings. Carriage may occur at a number of body sites and for short, intermediate, and long terms. A number of approaches have been taken to interrupt the linkage of staff-patient spread, but most emphasis has been placed on handwashing and the treatment of staff MRSA carriers. The importance of healthcare workers in transmission has been viewed with varying degrees of interest, and several logistical problems have arisen when healthcare worker screening is brought to the forefront. There is now considerable support for the screening and treatment of healthcare workers, but it is suggested that the intensity of any such approach must consider available resources, the nature of the outbreak, and the strength of epidemiological associations. The task of assessing healthcare personnel carriage in any context should be shaped with due regard to national and international guidelines, should be honed and practiced according to local needs and experience, and must be patient-oriented.

Screening for methicillin-resistant Staphylococcus aureus (MRSA) carriage on admission to a geriatric hospital

Our objective is to identify risk factors for carriage of MRSA on admission to a geriatric hospital where MRSA is endemic. A prospective screening for MRSA carriage was conducted by swabbing anterior nares and anal skin for 6 weeks. One hundred and thirty-eight patients aged over 65 were enrolled after obtaining their informed consent. Swabs of anterior nares and anal skin of patients were submitted for culture for MRSA. The demographic, administrative, and clinical data for each participant were recorded, and their association with MRSA carriage was determined by stepwise regression analysis. MRSA was recovered from 11 patients (11/138 patients, 8.0%), and from anal skin in 8 of them. Without screening of anal skin, 5 out of 11 carriers had been missed. Multivariate analysis revealed that hypoalbuminemia (adjusted risk ratio, RR=6.39, 95% confidence interval, CI=1.08-37.84) and bedridden status (RR=8.26, CI=1.04-65.31) were independent risk factors. Screening of elderly patients for gastrointestinal colonization on admission had implications for early detection of the reservoir of MRSA. Systematic selective screening for MRSA carriage targeting high-risk patients with hypoalbuminemia or bedridden status would be useful for infection control of this resistant organism.

Comparison of three chromogenic media and enrichment broth media for the detection of methicillin-resistant Staphylococcus aureus from mucocutaneous screening specimens : Comparison of MRSA chromogenic media

This study compares the performance of three chromogenic culture agar plates, chromID MRSA, MRSA-Screen and MRSA-Select, by challenging with a collection of Staphylococcus aureus strains and screening samples obtained from hospitalised patients. All chromogenic media showed excellent sensitivity (>95%) and specificity after 18 h on the methicillin-resistant Staphylococcus aureus (MRSA) collection strains, but the specificity of MRSA-Screen decreased markedly after 42 h. Sixty-eight of 1,002 screening specimens yielded MRSA on at least one medium. The sensitivity of all media to detecting MRSA after 18 h was <50%, but this increased to 75% (chromID MRSA), 81% (MRSA-Screen) and 72% (MRSA-Select) after 42 h and 85% after enrichment and plating on the same media. The specificity at 18 h was excellent, but was significantly lower for MRSA-Screen after 42 h and enrichment. In conclusion, all media showed equivalent sensitivities after 18 h of incubation and performed better when enriched before inoculation. MRSA-Screen was more sensitive but less specific than the two other media after 42 h of incubation.

Meticillin-resistant Staphylococcus aureus: the modern-day challenge

There are numerous resistant microorganisms but meticillin-resistant Staphylococcus aureus (MRSA) is probably the most notorious. MRSA is a resistant variation of the common bacterium, Staphylococcus aureus, that has developed the ability to survive treatment with a number of beta-lactam antibiotics, including meticillin. The focus of this article is a narrative literature review concerning the challenge that MRSA presents to nurses and other healthcare workers. A historical overview of antimicrobial resistance and the origins of MRSA are given, together with the factors involved in the persistence of antimicrobial resistance. The relevant microbiology, pathogenesis and epidemiology of MRSA will be discussed to provide a detailed rationale for the contemporary management of this persistent, resistant organism.

Sensitivities of nasal and rectal swabs for detection of methicillin-resistant Staphylococcus aureus colonization in an active surveillance program

All medical and high-risk surgical patients were screened for methicillin-resistant Staphylococcus aureus colonization over 3.5 years. The sensitivities of nasal and rectal swabs were 68% and 62%, respectively. Naris and open-skin-site swabs detected 467 (74%) of 627 adult carriers identified. Rectal swabs detected an additional 160 (26%) carriers.