Active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) decreases the incidence of MRSA bacteremia

The Active Surveillance of Staphylococcus aureus using Polymerase Chain Reaction-based Identification Method among Hospitalized-patient of Haji Adam Malik General Hospital, Medan, Indonesia

BACKGROUND: Active surveillance of methicillin-resistant Staphylococcus aureus (MRSA) carriers is associated with the lower incidence of bacteremia and lower mortality rates throughout literature; yet, this important step still remains problematic for developing countries, particularly Indonesia. AIM: The study aimed to demonstrate MRSA colonization rate in Haji Adam Malik Hospital, Medan, Indonesia. MATERIALS AND METHODS: The study enrolled 200 mucocutaneous isolates obtained from hospitalized patients during a 1-year period of study (2018). VITEK-2 system in addition to standard bacterial identification, such as gram staining, latex agglutination test, and hemolysis pattern, was performed to select S. aureus colonies in two different laboratories, Microbiology laboratory of Haji Adam Malik General Hospital and Multidisciplinary Laboratory, Faculty of Medicine, Universitas Sumatera Utara, for polymerase chain reaction (PCR) examination. RESULTS: Based on the VITEK-2 system preliminary identification, there were 80 S. aureus colonies which then underwent PCR examination. Through standard PCR assay, there were 32 bacterial isolates contained the mecA gene and it can be determined MRSA colonization rate of the hospital was 16% with consistent results of standard bacterial identification. CONCLUSIONS: Active surveillance of MRSA carriers is mandatory and urged it as a regular program in a hospital setting to decrease MRSA transmission rate.

Bugs and Drugs: Collaboration Between Infection Prevention and Antibiotic Stewardship

Overall goals of antibiotic stewardship and infection prevention programs are to improve patient safety as it pertains to risk of infection or multidrug-resistant organism (MDRO) acquisition. Although the focus of day-to-day activities may differ, the themes of surveillance, education, clinician engagement, and multidisciplinary interactions are prevalent in both programs. Synergistic work between programs has yielded benefits in prevention of MDROs, surgical site infections, Clostridioides difficile infection, and reducing inappropriate testing and treatment for asymptomatic bacteriuria. Collaboration between programs can help maximize resources and minimize redundant work to keep issues related to bugs and drugs at bay.

High Gastrointestinal Colonization Rate with Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Hospitalized Patients: Emergence of Carbapenemase-Producing K. pneumoniae in Ethiopia

We investigated the gastrointestinal colonization rate and antibiotic resistance patterns of Extended-Spectrum Beta-Lactamase (ESBL)- producing Escherichia coli and Klebsiella pneumoniae in hospitalized patients admitted at Ethiopia's largest tertiary hospital. Fecal samples/swabs from 267 patients were cultured on chrome agar. ESBL. Bacterial species identification, verification of ESBL production and antibiotic susceptibility testing were done using Vitek 2 system (bioMérieux, France). Phenotype characterization of ESBL-E.coli and ESBL- K.pneumoniae was done using Neo-Sensitabs™. ESBL positivity rate was much higher in K. pneumoniae (76%) than E. coli (45%). The overall gastrointestinal colonization rate of ESBL producing Enterobacteriaceae (ESBL-E) in hospitalized patients was 52% (95%CI; 46%-58%) of which, ESBL-E. coli and K.pneumoniae accounted for 68% and 32% respectively. Fecal ESBL-E carriage rate in neonates, children and adults was 74%, 59% and 46% respectively. Gastrointestinal colonization rate of ESBL-E.coli in neonates, children and adults was 11%, 42% and 42% respectively. Of all E. coli strains isolated from adults, children and neonates, 44%, 49% and 22% were ESBL positive (p = 0.28). The prevalence of ESBL-K.pneumoniae carriage in neonates, children and adults was 68%, 22% and 7% respectively. All K. pneumoniae isolated from neonates (100%) and 88% of K. pneumoniae isolated from children were ESBL positive, but only 50% of K.pneumoniae isolated from adults were ESBL positive (p = 0.001). Thirteen patients (5%) were carriers of both ESBL-E.coli and ESBL-KP. The overall carrier rate of ESBL producing isolates resistant to carbapenem was 2% (5/267), all detected in children; three with E.coli HL cephalosporinase (AmpC), resistant to ertapenem and two with K. pneumoniae Carbapenemase (KPC) resistant to meropenem, ertapenem and impenem. We report a high gastrointestinal colonization rate with ESBL-E and the emergence of carbapenems-resistant K. pneumoniae in Ethiopia. Urgent implementation of infection control measures, and surveillance are urgently needed to limit the spread within healthcare facilities and further to the community.

Cost Analysis of an Intervention to Prevent Methicillin-Resistant Staphylococcus Aureus (MRSA) Transmission

INTRODUCTION

Our objective was to assess the cost implications of a vertical MRSA prevention program that led to a reduction in MRSA bacteremia.

METHODS

We performed a matched historical cohort study and cost analysis in a single hospital in Israel for the years 2005-2011. The cost of MRSA bacteremia was calculated as total hospital cost for patients admitted with bacteremia and for patients with hospital-acquired bacteremia, the difference in cost compared to matched controls. The cost of prevention was calculated as the sum of the cost of microbiology tests, single-use equipment used for patients in isolation, and infection control personnel.

RESULTS

An average of 20,000 patients were screened yearly. The cost of prevention was $208,100 per year, with the major contributor being laboratory cost. We calculated that our intervention averted 34 cases of bacteremia yearly: 17 presenting on admission and 17 acquired in the hospital. The average cost of a case admitted with bacteremia was $14,500, and the net cost attributable to nosocomial bacteremia was $9,400. Antibiotics contributed only 0.4% of the total disease management cost. When the annual cost of averted cases of bacteremia and that of prevention were compared, the intervention resulted in annual cost savings of $199,600.

CONCLUSIONS

A vertical MRSA prevention program targeted at high-risk patients, which was highly effective in preventing bacteremia, is cost saving. These results suggest that allocating resources to targeted prevention efforts might be beneficial even in a single institution in a high incidence country.

Topical Therapy for Methicillin-Resistant Staphylococcus aureus Colonization Impact on Infection Risk

Objective.

We evaluated the usefulness of topical decolonization therapy for reducing the risk of methicillin-resistant Staphylococcus aureus (MRSA) infection among MRSA-colonized inpatients.

Design.

Retrospective cohort study.

Setting and Intervention.

Three hospitals with universal surveillance for MRSA; at their physician's discretion, colonized patients could be treated with a 5-day course of nasal mupirocin calcium 2%, twice daily, plus Chlorhexidine gluconate 4% every second day.

Patients and Methods.

MRSA carriers were later retested for colonization (407 subjects; study 1) or followed up for development of MRSA infection (933 subjects; study 2). Multivariable methods were used to determine the impact of decolonization therapy on the risks of sustained colonization (in study 1) and MRSA infection (in study 2).

Results.

Independent risk factors for sustained colonization included residence in a long-term care facility (odds ratio [OR], 1.8 [95% confidence interval {CI}, 1.1–3.2]) and a pressure ulcer (OR, 2.3 195% CI, 1.2–4.4]). Mupirocin at any dose decreased this risk, particularly during the 30-60-day period after therapy; mupirocin resistance increased this risk (OR, 4.1 [95% CI, 1.6–10.7]). Over a median follow-up duration of 269 days, 69 (7.4%) of 933 patients developed infection. Independent risk factors for infection were length of stay (hazard ratio [HR], 1.2 per 5 additional days [95% CI, 1.0–1.4]), chronic lung disease (HR, 1.7 [95% CI, 1.0–2.8]), and receipt of non-MRSA-active systemic antimicrobial agents (HR, 1.8 [95% CI, 1.1–3.1]). Receipt of mupirocin did not affect the risk of infection, although there was a trend toward delayed infection among patients receiving mupirocin (median time to infection, 50 vs 15.5 days; P = .06).

Conclusions.

Mupirocin-based decolonization therapy temporarily reduced the risk of continued colonization but did not decrease the risk of subsequent infection.

Recommendations For Metrics For Multidrug-Resistant Organisms In Healthcare Settings: SHEA/HICPAC Position Paper

Monitoring multidrug-resistant organisms (MDROs) and the infections they cause in a healthcare setting is important to detect newly emerging antimicrobial resistance profiles, to identify vulnerable patient populations, and to assess the need for and effectiveness of interventions; however, it is unclear which metrics are the best, because most of the metrics are not standardized. This document describes useful and practical metrics and surveillance considerations for measuring MDROs and the infections they cause in the practice of infection prevention and control in healthcare settings. These metrics are designed to aid healthcare workers in documenting trends over time within their facility and should not be used for interfacility comparison.

Systematic literature analysis and review of targeted preventive measures to limit healthcare-associated infections by meticillin-resistant Staphylococcus aureus

Meticillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated infections in Europe. Many examples have demonstrated that the spread of MRSA within healthcare settings can be reduced by targeted infection control measures. The aim of this systematic literature analysis and review was to summarise the evidence for the use of bacterial cultures for active surveillance the benefit of rapid screening tests, as well as the use of decolonisation therapies and different types of isolation measures. We included 83 studies published between 2000 and 2012. Although the studies reported good evidence supporting the role of active surveillance followed by decolonisation therapy, the effectiveness of single-room isolation was mostly shown in non-controlled studies, which should inspire further research regarding this issue. Overall, this review highlighted that when planning the implementation of preventive interventions, there is a need to consider the prevalence of MRSA, the incidence of infections, the competing effect of standard control measures (e.g. hand hygiene) and the likelihood of transmission in the respective settings of implementation.

Consensus statement on the management of methicillin-resistant Staphylococcus aureus nosocomial pneumonia in Asia

Nosocomial pneumonia (NP; encompassing hospital-acquired, health care-associated and ventilator-associated pneumonia) is one of the most common nosocomial infections and is associated with a mortality rate of 18.7%-40.8% in Asian countries. The burden of methicillin-resistant Staphylococcus aureus (MRSA) infections in Asia is high, and approximately 13% of NP cases in Asia are caused by this pathogen. Evidence regarding optimal management of MRSA NP continues to evolve and is complicated by the fact that a significant proportion of cases are likely to be caused by isolates with reduced susceptibility to the main therapeutic agent, vancomycin. The Asian Consensus Taskforce on MRSA Nosocomial Pneumonia has developed this statement to provide consensus points on diagnosis, antimicrobial treatment and prevention strategies for MRSA NP in the Asian context, based on our review of Asian data, previous international guidelines and recent scientific evidence.

Methicillin-resistant Staphylococcus aureus risk profiling: who are we missing?

Background

Targeted screening of patients at high risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage is an important component of MRSA control programs, which rely on prediction tools to identify those high-risk patients. Most previous risk studies reported a substantial rate of patients who are eligible for screening, but failed to be enrolled. The characteristics of these missed patients are seldom described. We aimed to determine the rate and characteristics of patients who were missed by a MRSA screening programme at our institution to see how the failure to include these patients might impact the accuracy of clinical prediction tools.

Findings

From March-June 2010 all patients admitted to 13 internal medicine wards at the University of Geneva Hospital (HUG) were prospectively screened for MRSA carriage. Of 1968 patients admitted to the ward, 267 patients (13.6%) failed to undergo appropriate MRSA screening. Forty-one (2.4%) screened patients were MRSA carriers at admission. On multivariate regression, patients who were missed by screening were more likely to be aged < 50 years (OR 2.4 [1.4-3.9]), transferred to internal medicine from another ward in the hospital (OR 2.8 [1.1-7.1]), and have a history of malignancy (OR 3.2[2.1-5.1]). There was no significant difference in the rate of previous MRSA carriage between screened and unscreened patients.

Conclusions

Our findings highlight the potential bias that “missed” patients may introduce into MRSA risk scores. Reporting on the proportions and characteristics of missed patients is essential for accurate interpretation of MRSA prediction tools.

MRSA nasal colonization in children: prevalence meta-analysis, review of risk factors and molecular genetics

BACKGROUND

We report a meta-analysis of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization prevalence in children and a review of the risk factors as well as molecular genetic characterization.

METHODS

All relevant studies reporting prevalence data on MRSA nasal colonization in children published between January 2000 and August 2010 were retrieved from the MEDLINE database and analyzed.

RESULTS

After screening 544 studies, 50 studies were included. We obtained an estimate of MRSA prevalence of 2.7% (95% confidence interval [CI]: 2.2-3.1); of 5.2% (95% CI: 3.1-7.3) in children with underlying conditions and of 2.3% (95% CI: 1.8-2.7) in healthy children; 5.4% (95% CI: 3.1-7.7) in children recruited in hospitals and 3% (95% CI: 2.4-3.6) in children recruited in the community. Staphylococcal cassette chromosome mec type IV is the most diffused cassette globally.

CONCLUSION

The hospital remains the environment where the microorganism circulates most. Children with underlying conditions could act as vectors of microorganisms between the hospital and the community. MRSA prevention strategies should be tailored to each specific institution, taking into account the nosocomial prevalence of MRSA nasal colonization and infections, and the prevalence of nasal colonization in the community that refers to the specific health care center.

Patient-level factors associated with methicillin-resistant Staphylococcus aureus carriage at hospital admission: a systematic review

BACKGROUND

Selective methicillin-resistant Staphylococcus aureus (MRSA) screening programs target high-risk populations. To characterize high-risk populations, we conducted this systematic review to identify patient-level factors associated with MRSA carriage at hospital admission.

METHODS

Studies were identified in the MEDLINE (1950-2011) and EMBASE (1980-2011) databases. English studies were included if they examined adult populations and used multivariable analyses to examine patient-level factors associated with MRSA carriage at hospital admission. From each study, we abstracted details of the population, the risk factors examined, and the association between the risk factors and MRSA carriage at hospital admission.

RESULTS

Our electronic search identified 972 citations, from which we selected 27 studies meeting our inclusion criteria. The patient populations varied across the studies. Ten studies included all patients admitted to hospital, and the others were limited to specific hospital areas. MRSA detection methods also varied across studies. Ten studies obtained specimens from the nares only, whereas other studies also swabbed wounds, catheter sites, and the perianal region. Methods of MRSA diagnoses included polymerase chain reaction tests, cultures in various agar mediums, and latex agglutination tests. Patient age, gender, previous admission to hospital, and previous antibiotic use were the risk factors most commonly examined. The risk factor definition and study methods varied among studies to an extent that precluded meta-analysis.

CONCLUSION

The existing literature cannot be used to identify risk factors for MRSA colonization at the time of hospitalization. Future studies should be aware of the differences in the existing literature and aim to develop standardized risk factor definitions.

A perspective on the evidence regarding methicillin-resistant Staphylococcus aureus surveillance

Two prominent studies have been used by policy makers to prevent the enactment of standards of care regarding active surveillance of patients with methicillin-resistant Staphylococcus aureus in hospital settings. In this brief review and perspective of those studies, we contend that both studies have serious limitations (i.e., the intervention group was not given optimal intervention) that may not have been scrutinized by many policy makers, health officials, and other researchers. These studies seem to have had a disproportionate impact on health-care policy despite their limitations. Furthermore, health-care policy and treatment standards need to reflect the preponderance of evidence with appropriate weight given to research studies based on their strengths and limitations. Only then can treatment standards that are effective against methicillin-resistant Staphylococcus aureus be adopted or refuted.

High prevalence of Panton-Valentine leukocidin among methicillin-sensitive Staphylococcus aureus colonization isolates in rural Iowa

Recent studies have shown that livestock can carry Staphylococcus aureus and transmit it to human caretakers. We conducted a pilot study to determine the prevalence and molecular epidemiology of S. aureus among rural Iowans, including individuals with livestock contact. Nasal and throat swabs were collected and plated onto selective media to isolate methicillin-susceptible and methicillin-resistant S. aureus (MRSA), followed by antibiotic resistance testing and molecular analysis of the isolates. While no MRSA was detected, overall, 23.7% (31/131) of participants were found to harbor S. aureus in their nose, throat, or both. Fifteen isolates displayed resistance to one or more tested antibiotics, and the Panton-Valentine leukocidin (PVL) genes were present at a high level (29% [9/31] of S. aureus-positive participants). Younger age and tobacco use were associated with increased risk of S. aureus carriage. Our results suggest that carriage of PVL-positive S. aureus is common among rural Iowans, even in the absence of detectable MRSA colonization.

Risk factors for positive admission surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci in a neurocritical care unit

OBJECTIVE

Hospitals are under increasing pressure to perform active surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. This study aimed to identify patients at low and high risk for positive admission surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in a neurocritical care unit using readily ascertainable historical factors.

DESIGN

Before/after study with nested case/control study.

SETTING

Neurocritical care unit of an academic hospital.

PATIENTS

During the intervention period (July 2007 to June 2008), after implementation of an admission surveillance culture screening program for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus, 2,059 patients were admitted to the neurocritical care unit for a total of 5,957 patient days.

INTERVENTIONS

Cases had positive methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus admission surveillance cultures within 48 hrs of hospital admission. Controls had negative cultures.

MEASUREMENTS AND MAIN RESULTS

Admission surveillance cultures grew methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in 35 of 823 (4.3%) and 19 of 766 (2.5%) patients, respectively. Factors significantly associated with both methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus colonization were intravenous antibiotics and hospitalization in the past year, immunocompromised health status, intravenous drug use, long-term hemodialysis, and known prior carrier status. Transfer from an outside hospital and residence in a long-term care facility in the past year were associated with vancomycin-resistant Enterococcus colonization. Classification and regression tree analysis was used to identify variables that best predicted positive methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus surveillance cultures. A classification and regression tree model with six of these variables yielded an overall cross-validated predictive accuracy of 87.12% to detect methicillin-resistant Staphylococcus aureus colonization. For vancomycin-resistant Enterococcus, a four-variable classification and regression tree model (intravenous antibiotics, hospitalization and long-term patient care in the past year, and not being "admitted same day of procedure") optimized the predictive accuracy (94.91%). There were no cases of vancomycin-resistant Enterococcus colonization in patients admitted same day of procedure.

CONCLUSIONS

Colonization with methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in neurocritical care patients can be predicted with a high predictive accuracy using decision trees that include four to six readily attainable risk factors. In our setting, in the absence of these risk factors and in patients admitted from home for neurosurgical procedures, routine admission surveillance cultures to the intensive care unit may not be cost-effective.

Active surveillance culturing impacts methicillin-resistant Staphylococcus aureus acquisition in a pediatric intensive care unit

OBJECTIVE

To determine whether active surveillance culturing for methicillin-resistant Staphylococcus aureus (MRSA) decreases nosocomial MRSA acquisition in the pediatric intensive care unit.

DESIGN

Before and after observational study.

SETTING

A tertiary care, 20-bed, pediatric intensive care unit.

PATIENTS

All patients admitted to the pediatric intensive care unit.

INTERVENTIONS

Anterior nares cultures for MRSA were obtained on admission and weekly in the pediatric intensive care unit from January 2007 to December 2009 as part of a hospital quality improvement project.

MEASUREMENTS AND MAIN RESULTS

MRSA admission prevalence and nosocomial incidence density were determined retrospectively for 2006 and prospectively for 2007-2009. Nosocomial MRSA incidence density during the intervention period was determined monthly and analyzed by trend analysis by using a general linear model. The correlation of active surveillance culturing compliance with nosocomial acquisition of MRSA was analyzed. Possible confounding by healthcare worker hand hygiene compliance observed during the intervention period was also analyzed by multivariate linear regression analysis. The yearly MRSA incidence density significantly decreased from 2006 to 2009 (6.88 per 1,000 patient days to 1.45 per 1,000 patient days, p < .001) and from 2007 to 2009 (7.32 per 1,000 patient days to 1.45 per 1,000 patient days, p < .001). Trend analysis demonstrated a significant decline in MRSA acquisition over time following the introduction of active surveillance culturing (p < .001). Surveillance culturing was significantly associated with the decline in MRSA acquisition observed in the pediatric intensive care unit by multivariate regression analysis when controlling for hand hygiene (p = .01).

CONCLUSIONS

Active surveillance culturing resulted in significantly decreased nosocomial acquisition of MRSA in a pediatric intensive care unit setting. Admission and weekly active surveillance culturing appears to be an effective tool to decrease the spread of MRSA in the pediatric intensive care unit, independent of improvement in hand hygiene compliance. The impact on hospital-acquired MRSA infections and the cost benefit of active surveillance culturing require further study.

An integrative review of infection prevention and control programs for multidrug-resistant organisms in acute care hospitals: a socio-ecological perspective

BACKGROUND

The infection rates of multidrug-resistant organisms (MDRO) are increasing in Canada and the United States. The prevention and control of MDRO infections remain an important issue in acute care hospitals. Although comprehensive infection prevention and control programs have been recommended, there is little evidence to date of their effectiveness or of what aspects are most important.

OBJECTIVES

Our objectives were to review and critique the literature on the relationship between an MDRO infection and control program and MDRO rates in acute care hospitals.

METHODS

Studies including original research published between January 1, 1998, and May 14, 2009, were identified through MEDLINE, CINAHL, EMBASE, PUBMED, The Cochrane Library, and expert consultation. A comprehensive search strategy was developed with a librarian to find studies that covered the main subject areas of this integrative review.

RESULTS

Of the 1,382 papers retrieved, 47 were reviewed, and 32 studies met the inclusion criteria. The interventions in the included studies were assessed using the tier 1/tier 2 framework. A total of 18 (56.25%) studies had an administrative measure as an intervention; 20 (62.5%) studies had education and training of health care personnel; 8 (25.0%) studies had judicious use of antimicrobial agents; 17 (53.1%) studies used surveillance; 24 (75.0%) studies had infection control precautions to prevent transmission; 7 studies (21.9%) introduced environmental measures; and 9 (28.1%) studies used patient decolonization. Although all the 32 studies were quasiexperimental studies, only 2 (5.9%) studies provided sample size calculations, and only 5 studies reported confounding factors. Whereas 27 used an interrupted time series design and 2 were controlled pre- and post-intervention designs, 3 were pre- and post-intervention without control groups.

CONCLUSION

This integrative review demonstrated that the evidence of the relationship between MDRO infection prevention and control programs and the rates of MDRO is weak. Although major methodologic weaknesses exist in the published literature making it not possible to exclude other plausible explanations for the reduction of the acquisition of MDRO, the overall evidence does support the use of multiple interventions to reduce the rates of MDRO in acute care hospitals. Whereas it is unclear which bundles of interventions are effective, there is a clear suggestion that multiple simultaneous interventions can be effective in reducing MDRO infections. In addition, despite the limitations of interrupted time series, multiple studies employing active surveillance cultures were associated with reduced MDRO infections. Future individual reports of outbreaks and intervention studies should be written in a standardized manner using the recommended Outbreak Reports and Intervention Studies of Nosocomial Infection (ORION) guidelines. Further research is needed on the proposed tier 1/tier 2 framework clearly indicating all the interventions implemented.

The value of multiple surveillance cultures for methicillin-resistant Staphylococcus aureus

BACKGROUND

We evaluated our experience in a low prevalence setting to determine the extent to which multiple swabs increased detection rates and the incremental costs of doing so.

METHODS

Nasal and groin swabs submitted in pairs were cultured onto a single plate (Oxoid MRSA Denim Blue Agar; Oxoid Company, Napean, ON, Canada). We determined whether MRSA was detected when swabs submitted in the preceding 3 days were negative. We explored the costs associated with screening and of each additional colonized patient detected.

RESULTS

In all, 60,049 paired nose and perineal swabs were submitted from 21,599 patients. In all, there were 12,750 duplicate, 1437 triplicate, and 112 instances when >4 swabs were processed within 3 days. The first culture was positive in 106 of 12,750 (0.83%%), 42 of 12,750 (0.33%) on the second when the first was negative, 7 of 1642 (0.43%) on the third or subsequent swab pair when the preceding 2 were negative.

CONCLUSION

Overall, the sensitivity of the first of multiple cultures of a set was 74.3%. Had the 14,392 multiple samples not been submitted, 49 colonized patients would not have been identified. Additional laboratory costs associated with multiple samples equaled $2088 per patient identified.

Increased use of alcohol-based hand sanitizers and successful eradication of methicillin-resistant Staphylococcus aureus from a neonatal intensive care unit: a multivariate time series analysis

BACKGROUND

We analyzed time series data to investigate factors that contributed to the gradual decrease and eventual eradication of methicillin-resistant Staphylococcus aureus (MRSA) from our neonatal intensive care unit (NICU).

METHODS

A multivariate adjusted autoregressive integrated moving average (ARIMA) model was used for time series analyses of monthly MRSA incidence density rates and their predictors in the NICU from July 2003 to July 2009.

RESULTS

Based on our ARIMA (0,1,1), which is a nonseasonal and nonstationary moving average model, the monthly pooled mean of the amount of alcohol-based hand sanitizer used for 1 patient per day (lag time, 0 month; P = .011) was the only factor significantly associated with the MRSA incidence density rates. MRSA colonization pressure, patient-to-nurse ratios, and bed occupancy rates were not associated with MRSA acquisition in the NICU. Active surveillance, which had been practiced since the late 1980s, alone was not sufficient to control the spread of MRSA until it was accompanied by enhanced hand hygiene.

CONCLUSION

Increasing the use of alcohol-based hand sanitizers by improving accessibility and providing periodic hand hygiene training sessions to health care workers is strongly recommended for decreasing the risk of MRSA acquisition among neonates in NICU settings.

Nasal colonization with methicillin-resistant Staphylococcus aureus: clinical implications and treatment

Methicillin-resistant Staphylococcus aureus (MRSA) has become an increasingly important pathogen during the past 30 years, and infections due to MRSA are associated with substantial morbidity and mortality. Despite intensive infection control measures, the prevalence of MRSA has increased significantly, and the organism has become endemic in many hospitals worldwide. Asymptomatic nasal carriage of MRSA has been identified as a major risk factor for subsequent S. aureus infection in multiple settings and populations. As a result, considerable interest exists in developing decolonization strategies, with the ultimate goal of reducing the incidence of MRSA infection. Approaches to decolonization have included the use of systemic and inhalation anti-biotics, antiseptic washes, and topical antimicrobials.

Evaluation of single and double-locus real-time PCR assays for methicillin-resistant Staphylococcus aureus (MRSA) surveillance

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen, representing an infection control challenge. Conventional MRSA screening takes up to three days, therefore development of rapid detection is essential. Real time-PCR (rt-PCR) is the fastest method fulfilling this task. All currently published or commercially available rt-PCR MRSA assays relay on single or double-locus detection. Double-locus assays are based on simultaneous detection of mecA gene and a S. aureus-specific gene. Such assays cannot be applied on clinical samples, which often contain both coagulase-negative staphylococci (CoNS) and S. aureus, either of which can carry mecA. Single-locus assays are based on detection of the staphylococcal cassette chromosome mec (SCCmec) element and the S. aureus-specific orfX gene, assuming that it is equivalent to mecA detection.

Findings

Parallel evaluation of several published single and double-locus rt-PCR MRSA assays of 150 pure culture strains, followed by analysis of 460 swab-derived clinical samples which included standard identification, susceptibility testing, followed by PCR detection of staphylococcal suspected isolates and in-PCR mixed bacterial populations analysis indicated the following findings.

Pure cultures analysis indicated that one of the single-locus assay had very high prevalence of false positives (Positive predictive value = 77.8%) and was excluded from further analysis. Analysis of 460 swab-derived samples indicated that the second single-locus assay misidentified 16 out of 219 MRSA's and 13 out of 90 methicillin-sensitive S. aureus's (MSSA) were misidentified as MRSA's. The double-locus detection assay misidentified 55 out of 90 MSSA's. 46 MSSA containing samples were misidentified as MRSA and 9 as other than S. aureus ending with low positive predicted value (<85%) and very low specificity (<62%).

Conclusion

The results indicate that high prevalence of false-positive and false-negative reactions occurs in such assays.

Characterization of the best anatomical sites in screening for methicillin-resistant Staphylococcus aureus colonization

The purpose of this study was to identify differences in the sensitivity of anatomical sites sampling for methicillin-resistant Staphylococcus aureus (MRSA) colonization related to age, gender, clinical situation, and acquisition source as a base for screening protocols. We used a database that included all MRSA-positive cultures (Carmel Medical Center, 2003-2006) taken from nares, throat, perineum, and infection sites. The study population of 597 patients was divided into: "screening sample" (SS), which were cases of routine screening, and "clinical diagnostic sample" (CDS), which were patients with concurrent MRSA infection. MRSA acquisition sources were classified as internal medicine, surgical, referral patients, or intensive care unit (ICU). CDS patients were older than SS patients (median age 78 vs. 74 years, p = 0.0002), more commonly throat colonized (47.5% vs. 31.8%, p = 0.0001), and colonized in more multiple sites (65.7% vs. 43.3% were colonized in three sites in the CDS and SS groups, respectively, p < 0.001) than SS patients. In the SS, group throat colonization was higher in internal medicine wards than in the ICU (odds ratio [OR] = 3.98, p < 0.0001). In the CDS group, perineal colonization was more common in referral patients than in the ICU (OR = 4.52, p < 0.05). Patient age was the most influential factor on nares and multiple sites colonization in the SS and CDS groups, respectively. Our data support multiple sites sampling. Throat cultures are crucial in MRSA-infected patients and internal medicine ward patients. Multiple body sites colonization is more likely in older or MRSA-infected patients, affecting decisions regarding eradication using topical antibiotics.

Epidemiology and associated factors for nosocomial methicillin-resistant Staphylococcus aureus infection in a tertiary-care hospital

We analysed nosocomial MRSA cases between January 2004 and December 2006 in a retrospective case-control study in a 250-bed tertiary-care teaching hospital. During the study period, 265 nosocomial Staphylococcus aureus infections were identified in 231 patients. There was a significant increase in methicillin resistance in isolates (MRSA) from these infections with frequencies for 2004 of 39/88 (44.3%), 2005 (62/80, 77.5%), and 2006 (75/97, 77.3%) (P<0.001). Multivariate analysis showed that associated factors for nosocomial MRSA infection were prolonged hospitalization (OR 3.982, 95% CI 2.235-7.094, P<0.001), mechanical ventilation (OR 3.052, 95% CI 1.666-5.590, P<0.001), surgical operation (OR 2.032, 95% CI 1.102-3.748, P=0.023), and male sex (OR 2.000, 95% CI 1.081-3.699, P=0.027). The determination of associated factors for methicillin resistance in nosocomial S. aureus infections in hospitals will play an important role in efforts to reduce MRSA infection rates.

Hospital-wide methicillin-resistant Staphylococcus aureus control program: A 5-year follow-up

We investigated the influence of different interventions (active surveillance, contact isolation, monitoring, and rapid diagnostic testing) on the number of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia cases. An interrupted time-series analysis was used. MRSA bacteremia cases were reduced by 70% when all interventions were in place. We proved monitoring to be an essential component.

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.

The value of infectious diseases specialists: non-patient care activities

Recent developments in health care have focused efforts on both the national and local levels to reduce unnecessary health care costs and the number of hospital stays while increasing the quality of care, particularly in the context of hospital-associated infections. Infectious diseases specialists who contract to oversee infection-control and antibiotic-stewardship programs are uniquely positioned to play a pivotal role in helping hospitals to prosper in this new environment. This article will detail the available data supporting the value of infectious diseases specialists in their roles of directing antimicrobial-management and infection-control programs, maintaining health care workers' well-being, and minimizing exposure. The evidence in support of the influence of infectious diseases specialists to achieve cost-savings, decrease the length of hospital stays, and improve outcomes is robust and can be used as the framework for negotiating appropriate compensation from hospital management for these activities. Presenting this information in an amicable but definitive framework may be the linchpin to the overall success of the movement to improve quality of care while minimizing hospital costs and antimicrobial use. Developing this ability is critical to infectious diseases specialists' success as they redefine their role in the quality-of-care and risk-management arenas.

Validation study of artificial neural network models for prediction of methicillin-resistant Staphylococcus aureus carriage

OBJECTIVE

Use of active surveillance cultures for methicillin-resistant Staphylococcus aureus (MRSA) for all patients admitted to the intensive care unit has been shown to reduce nosocomial transmission. However, the cost-effectiveness and the utility of implementing use of active surveillance cultures nationwide remain controversial. We sought to develop an artificial neural network (ANN) model that would predict the likelihood of MRSA colonization.

SETTING

Two acute care hospitals, one in Pittsburgh (hospital A) and one in Kaohsiung, Taiwan (hospital B).

METHODS

Nasal cultures were performed for all patients admitted to the hospitals. A total of 46 potential risk factors in hospital A and 86 potential risk factors in hospital B associated with MRSA colonization were assessed. Culture results were obtained; 75% of the data were used for training our ANN model, and the remaining 25% were used for validating our ANN model. The culture results were the "gold standard" for determining the accuracy of the model predictions.

RESULTS

The ANN model predictions were accurate 95.2% of the time for hospital A (sensitivity, 94.3%; specificity, 96.0%) and 94.2% of the time for hospital B (sensitivity, 96.6%; specificity, 91.8%), integrating all potential risk factors into the model. Only 17 potential risk factors were needed for the hospital A ANN model (accuracy, 90.9%; sensitivity, 98.5%; specificity, 83.4%), and only 20 potential risk factors were needed for the hospital B ANN model (accuracy, 90.5%; sensitivity, 96.6%; specificity, 84.3%), if the minimal risk factor method was used. Cross-validation analysis showed an average accuracy of 85.6% (sensitivity, 91.3%; specificity, 80.0%).

CONCLUSION

Our ANN model can be used to predict with an accuracy of more than 90% which patients carry MRSA. The false-negative rates were significantly lower than the false-positive rates in the ANN predictions, which can serve as a safety buffer in case of patient misclassification.

A pervasive body sensor network for measuring postoperative recovery at home

Patients going home following major surgery are susceptible to complications such as wound infection, abscess formation, malnutrition, poor analgesia, and depression, all of which can develop after the fifth postoperative day and slow recovery. Although current hospital recovery monitoring systems are effective during perioperative and early postoperative periods, they cannot be used when the patient is at home. Measuring and quantifying home recovery is currently a subjective and labor-intensive process. This case report highlights the development and piloting of a wireless body sensor network to monitor postoperative recovery at home in patients undergoing abdominal surgery. The device consists of wearable sensors (vital signs, motion) combined with miniaturized computers wirelessly linked to each other, thus allowing continuous monitoring of patients in a pervasive (unobtrusive) manner in any environment. Initial pilot work with results in both the simulated (with volunteers) and the real home environment (with patients) is presented.

Empiric therapy for febrile neutropenia: what are the choices?

The management of febrile neutropenia has evolved gradually over the years toward a risk-adapted strategy based on validated prediction rules by risk of complications. The drug choice for empiric therapy is influenced by several factors, either related to the patient or to the institution. Microbiological distribution of offending pathogens and their pattern of susceptibility to antibiotics are continuously changing. New mechanisms of resistance in both Gram-negative and -positive bacteria have emerged. Guidelines and general statements should always be considered with the local epidemiology.

Methicillin-resistant Staphylococcus aureus in critical care areas

In recent years the mainstay of treatment for hospital-associated MRSA infections has been vancomycin, but now vancomycin intermediate S aureus strains are beginning to emerge. Complete vancomycin resistant S aureus can develop, possessing the same vanA gene as vancomycin-resistant enterococcus. Four such isolates have been reported, three of which have been in the United States. There are new antibiotics being developed, but there is always a risk of resistance developing. There are some promising new ideas such as staphylococcal conjugate vaccines that reduce the rates of S aureus bacteremia for up to 10 months postimmunization in patients who have end stage renal disease receiving hemodialysis, but studies are ongoing. With all the uncertainty surrounding treatment, at least one medium has remained consistent and effective if used properly--infection control. But this requires complete support of all healthcare workers and hospital administration from the chief medical officer to doctors and nurses to environmental services personnel to take ownership of an effective infection control program. Who will advocate for more stringent infection control policies and for the equipment to successfully carry them out? Who will take the lead by ensuring implementation of infection control policies on a unit is effective? Who will hold themselves and other health care workers including physicians accountable to comply with these infection control policies every time they enter a patient's room? Nurses are on the front lines in the battle against antibiotic-resistant nosocomial infections such as MRSA, and we should not be apathetic or feel we are helpless. It is our duty as patient advocates not to take a spectator role but to answer these questions: "I will."