Revised guidelines for control of MRSA: applying appropriately-based recommendations

The prevalence of methicillin resistant Staphylococus aureus in orthopaedics in a non-selective screening policy

BACKGROUND

The aim of this study was to assess the true incidence and prevalence of MRSA colonisation and infection in the elective and trauma orthopaedic population in Rotherham District General Hospital.

MATERIALS AND METHODS

This prospective study non-selectively screened 690 consecutive trauma and elective orthopaedic patients over three months in 2005.

RESULTS

Of these, 27 were positive for either colonisation or wound infection with MRSA. Of those, 13 were previously known to have been colonised with MRSA and the 14 others were unexpectedly either colonised or subsequently developed wound infections. The new cases would not have been identified using any current selective screening protocol, as they did not fall into a high-risk category. Many were young, had no co-morbidities and no contact with hospitals in the past. Our study seems to indicate that selective screening will miss a significant number of cases.

CONCLUSION

We conclude that MRSA screening for all orthopaedic patients is needed when admitted to hospital, as colonisation is no longer confined to what has been previously identified as high-risk groups. The consequences of a subsequent MRSA infection have significant implications, socially, financially and clinically.

Financial implications of plans to combat methicillin-resistant Staphylococcus aureus (MRSA) in an orthopaedic department

INTRODUCTION

The aim of this study was to calculate retrospectively the cost of MRSA infections in the elective and trauma orthopaedic population in Rotherham District General Hospital in a 3-month period during 2005.

PATIENTS AND METHODS

A total of 686 patients were admitted to the orthopaedic wards and the surgical wounds 10 patients became infected with MRSA.

RESULTS

The cost of these infections when extrapolated over 12 months was pound384,000 excluding staff costs.

CONCLUSIONS

The key in the fight against MRSA in the hospital setting is multifactorial and requires a combination of measures. Our solution is: cohort nursing; non-selective screening of all admissions to the orthopaedic wards; use of a polymerase chain reaction as a diagnostic tool; ring-fencing of beds; and separate wound dressing rooms for each ward. The total cost is projected to be pound301,000.

Transmission via the face is one route of methicillin-resistant Staphylococcus aureus cross-infection within a hospital

BACKGROUND

It is generally accepted that hospital personnel must not touch their faces, and indeed must not elevate their hands above the shoulder in the ward, because many bacteria including Staphylococcus aureus colonize the face. However, possible methicillin-resistant Staphylococcus aureus (MRSA) cross-infection by way of faces has not yet been properly examined.

METHODS

One hundred and seventy-eight isolates from 159 inpatients from February 1999 to January 2000 were subjected to chromosomal DNA analysis by pulsed-field gel electrophoresis (PFGE).

RESULTS

The 178 MRSA isolates were classified into 43 PFGE types. Cross-infection was more frequent in the Department of Neurology [average number of patients per PFGE pattern (n/PFGE) = 4.0] than in the other six nonsurgical departments (n/PFGE = 1.0-1.6), and more frequent in four surgical departments (n/PFGE = 2.0-4.5) than in the other eight (n/PFGE = 1.0-1.7). In neurology, patients' faces were more often touched for examination of the cranial nerves than in the other departments. In the above four surgical departments, organs in the face were chiefly operated upon, and the patients' faces were also touched for care before and after the operation.

CONCLUSIONS

Our study reveals the possibility of MRSA being transmitted by way of patients' faces in a hospital.

[Methicillin resistant Staphylococcus aureus infection postoperatory complications and prognosis of patients with lower extremity amputations]

BACKGROUND AND OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with an increasing morbimortality when compared with other microorganisms. The aim of this study was to examine the complications and prognosis of the presence of MRSA in vascular patients with amputation of lower limbs.

PATIENTS AND METHOD

We included patients who had lower extremity amputation in our department in 2004 and displayed positive surgical wounds cultures. We compared patients with MRSA positive cultures with other microrganisms. We evaluated general characteristics, operative indications, surgical wounds microbiology, reamputations, morbimortality and mean time of stay in hospital.

RESULTS

117 patients (median age 73, 68% male) underwent lower extremity amputation. 82 of them had positive cultures and MRSA were isolated in 30% cases. Two two groups were comparable and no statistical differences were found in relation to reamputation rate, morbimortality and mean time of stay in hospital.

CONCLUSION

Presence of MRSA does not represent an additional risk of reamputation or an increase of postoperative complications. Careful wound surveillance, through wound debridement and optimal administration of antibiotics must be applied to all patients, regardless of the bacterial flora.

Potential use of copper surfaces to reduce survival of epidemic meticillin-resistant Staphylococcus aureus in the healthcare environment

Epidemic meticillin-resistant Staphylococcus aureus (EMRSA) emerged in the early 1980s with EMRSA-15 and -16 being the most prevalent strains within the UK. MRSA transmission between patients is largely via the hands of healthcare workers, and contamination of the hospital environment may occur. The objective of this study was to evaluate the effectiveness of copper and brass to reduce the viability of air-dried deposits of three MRSA strains [MRSA (NCTC 10442), EMRSA-1 (NCTC 11939) and EMRSA-16 (NCTC 13143)] compared with stainless steel. MRSA and EMRSA [10(7)colony-forming units (CFU)] were inoculated on to coupons (1 cm x 1 cm) of copper, brass or stainless steel and incubated at either 22 degrees C or 4 degrees C for various time periods. Viability was determined by resuspending removed CFUs and plating out on tryptone soy agar plates in addition to staining with the respiratory indicator fluorochrome 5-cyano-2,3-ditolyl tetrazolium. On pure copper surfaces, 10(7) MRSA, EMRSA-1 and EMRSA-16 were completely killed after 45, 60 and 90 min, respectively, at 22 degrees C. In contrast, viable organisms for all three strains were detected on stainless steel (grade 304) after 72 h at 22 degrees C. At 4 degrees C, complete kill was achieved on copper for all three strains within 6 h. The results demonstrate an antimicrobial effect of copper on MRSA, EMRSA-1 and -16 in contrast to stainless steel. Consequently, the contemporary application of stainless steel in hospital environments for work surfaces and door furniture is not recommended.

Methicillin-Resistant Staphylococcus Species in a Cardiac Surgical Intensive Care Unit: A 5-Year Experience

OBJECTIVES

Methicillin-resistant Staphylococcus is a growing problem in intensive care units (ICUs). The aim of this study was to describe the epidemiology of methicillin-resistant Staphylococcus isolates in a cardiac surgical ICU over a 5-year period and to determine the risk factors and outcome of this condition.

METHODS

During the period from January 1998 to July 2003, the clinical data of all adult patients who underwent cardiac surgery in a university hospital were prospectively recorded in a database; the perioperative clinical variables and microbiologic data were studied by means of univariate and multivariate analysis in order to identify risk factors for the development of methicillin resistance and in-hospital death.

RESULTS

Methicillin-resistant Staphylococcus species strains were isolated in 118 of 6,423 patients operated on during the study period (7.6 cases per 1,000 days of ICU stay), with a constant prevalence rate throughout the years. Methicillin-resistant Staphylococcus species have been the most frequently isolated microorganisms in the authors' ICU; 75% of Staphylococcus aureus and 95% of coagulase-negative staphylococci were methicillin resistant. In-hospital mortality in methicillin-resistant Staphylococcus-positive patients was 50.0% (59/118), whereas it was 1.7% (108/6305) in other patients (p < 0.0001). On multivariate analysis, methicillin-resistant Staphylococcus species isolation was the single risk factor with the strongest association with in-hospital death (odds ratio, 8.5; 95% confidence interval 4.9-14.7). In the present series, there were no isolates of vancomycin-resistant species (Enterococcus species or Staphylococcus species).

CONCLUSIONS

Staphylococcus species represent the most frequently isolated microorganisms in the authors' ICU. In-hospital mortality in cardiac surgical patients is strongly correlated to the isolation of methicillin-resistant Staphylococcus.

A PCR method for the identification of methicillin-resistant Staphylococcus aureus (MRSA) from screening swabs

AIM

The aim of this study was to assess the discriminatory power and potential turn around time (TAT) of a PCR-based method for the detection of methicillin-resistant Staphylococcus aureus (MRSA) from screening swabs.

METHODS

Screening swabs were examined using the current laboratory protocol of direct culture on mannitol salt agar supplemented with oxacillin (MSAO-direct). The PCR method involved pre-incubation in broth for 4 hours followed by a multiplex PCR with primers directed to mecA and nuc genes of MRSA. The reference standard was determined by pre-incubation in broth for 4 hours followed by culture on MSAO (MSAO-broth).

RESULTS

A total of 256 swabs was analysed. The rates of detection of MRSA using MSAO-direct, MSAO-broth and PCR were 10.2, 13.3 and 10.2%, respectively. For PCR, the sensitivity, specificity, positive predictive value and negative predictive values were 66.7% (95%CI 51.9-83.3%), 98.6% (95%CI 97.1-100%), 84.6% (95%CI 76.2-100%) and 95.2% (95%CI 92.4-98.0%), respectively, and these results were almost identical to those obtained from MSAO-direct. The agreement between MSAO-direct and PCR was 61.5% (95%CI 42.8-80.2%) for positive results, 95.6% (95%CI 93.0-98.2%) for negative results and overall was 92.2% (95%CI 88.9-95.5%).

CONCLUSIONS

(1) The discriminatory power of PCR and MSAO-direct is similar but the level of agreement, especially for true positive results, is low. (2) The potential TAT for the PCR method provides a marked advantage over conventional methods. (3) Further modifications to the PCR method such as increased broth incubation time, use of selective broth and adaptation to real-time PCR may lead to improvement in sensitivity and TAT.

Is Methicillin-Resistant Staphylococcus aureus More Virulent than Methicillin-Susceptible S. aureus? A Comparative Cohort Study of British Patients with Nosocomial Infection and Bacteremia

Staphylococcus aureus is the most common cause of hospital-acquired bacteremia. From 1995 through 2000, data on age, sex, patient specialty at time of first bacteremia, primary and secondary sites of infection, delay in initiating antimicrobial therapy, and patient outcome were prospectively recorded for 815 patients with nosocomial S. aureus bacteremia. The proportion of patients whose death was attributable to methicillin-resistant S. aureus (MRSA) was significantly higher than that for methicillin-susceptible S. aureus (MSSA) (11.8% vs. 5.1%; odds ratio [OR], 2.49; 95% confidence interval [CI], 1.46-4.24; P<.001). After adjustment for host variables, the OR decreased to 1.72 (95% CI, 0.92-3.20; P=.09). There was no significant difference between rates of disseminated infection (7.1% vs. 6.2% for MRSA-infected patients and MSSA-infected patients, respectively; P=.63), though the rate of death due to disseminated infection was significantly higher than death due to uncomplicated infection (37% vs. 10% for MRSA-infected patients [P<.001] and 37% vs. 3% for MSSA-infected patients [P<.001]). There was a strong statistical trend toward death due to nosocomial MRSA infection and bacteremia, compared with MSSA.

Carriage of methicillin-resistant Staphylococcus aureus, ceftazidime-resistant Gram-negative bacilli, and vancomycin-resistant enterococci before and after intensive care unit admission

OBJECTIVE

To measure patients' risk for acquiring antibiotic-resistant microorganisms associated with intensive care unit admission.

DESIGN

Prospective, observational study.

SETTING

Ten public hospitals including one university medical center.

PATIENTS

Consecutive patients admitted to ten intensive care units.

INTERVENTIONS

Serial patient surveillance cultures were screened for vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus (MRSA), ceftazidime-resistant Gram-negative bacilli (CR-GNB), Acute Physiology and Chronic Health Evaluation II score, and antibiotic and medical device exposures.

MEASUREMENTS AND MAIN RESULTS

A total of 1,697 patient admissions in ten intensive care units were enrolled. The overall carriage rate of antibiotic-resistant bacteria at intensive care unit entry was 12.1% for MRSA, 14% for CR-GNB and 4.7% for both. At discharge from the intensive care unit, new carriage of MRSA, CR-GNB, and both was found in 11.1%, 14.2%, and 2.4% of the patients, respectively. The acquisition rates in the individual units correlated highly and positively with proportion of patients with carriage at intensive care unit entry for both MRSA (n = 10, Pearson's r =.89, p < 0.001) and CR-GNB (n = 10, Pearson's r =.92, p < 0.001). By logistic regression, severity of illness (odds ratio, 1.4), length of stay (odds ratio, 1.7), use of penicillins (odds ratio, 1.9), and number of antibiotics (odds ratio, 1.2) and medical devices (odds ratio, 1.2) were independently associated with intensive care unit acquisition of MRSA. In comparison, variables independently associated with intensive care unit acquisition of CR-GNB were Acute Physiology and Chronic Health Evaluation II score (odds ratio, 1.5), number of antibiotics (odds ratio, 1.1), and artificial airway (odds ratio, 1.5).

CONCLUSIONS

These data suggest that hospitalization in the intensive care unit introduces significant risk to patients in terms of transmission of MRSA and/or CR-GNB. This risk seems to be influenced strongly by the proportion of patients with colonization at intensive care unit admission and is associated with severity of illness, length of stay, and exposures to antibiotics and medical devices.

Elimination of epidemic methicillin-resistant Staphylococcus aureus from a university hospital and district institutions, Finland

From August 1991 to October 1992, two successive outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) occurred at a hospital in Finland. During and after these outbreaks, MRSA was diagnosed in 202 persons in our medical district; >100 cases involved epidemic MRSA. When control policies failed to stop the epidemic, more aggressive measures were taken, including continuous staff education, contact isolation for MRSA-positive patients, systematic screening for persons exposed to MRSA, cohort nursing of MRSA-positive and MRSA-exposed patients in epidemic situations, and perception of the 30 medical institutions in that district as one epidemiologic entity brought under surveillance and control of the infection control team of Turku University Hospital. Two major epidemic strains, as well as eight additional strains, were eliminated; we were also able to prevent nosocomial spread of other MRSA strains. Our data show that controlling MRSA is possible if strict measures are taken before the organism becomes endemic. Similar control policies may be successful for dealing with new strains of multiresistant bacteria, such as vancomycin-resistant strains of S. aureus.