Surveillance Cultures For Methicillin-resistant Staphylococcus Aureus Research Articles

Predictive Role of Targeted, Active Surveillance Cultures for Detection of Methicillin-Resistant Staphylococcus aureus.

IntroductionMethicillin-resistant Staphylococcus aureus (MRSA) colonisation is an important source of healthcare-acquired infections. Reliable screening strategies for MRSA colonisation are essential for the timely implementation of infection control measures.AimThis study determined reliable MRSA screening sites to predict colonisation in resource-limited settings and estimated the impact of missed MRSA cases when shifting from multi- to single-site screening.MethodologyA cross-sectional study was conducted in patients with positive MRSA surveillance cultures from the routinely screened sites (nasal, axillary, groin, and throat) from January 2009 to December 2019.ResultsA total of 1906 screening tests were positive for MRSA cultures (n = 1345 patients). As a single site, the nasal cavity showed the highest MRSA detection, with a sensitivity of 66.8% (95% CI = 64–69) with 277.9 missed isolation days. Screening three or more anatomical sites detected 97–100% of MRSA cases, with 0–24.5 missed isolation days. Screening the axilla and groin separately or in combination showed a good clinical utility index (CUI) of >0.6 to <0.8, while an excellent CUI was obtained upon screening other site samples (>0.8). The combined nasal and throat cultures demonstrated a sensitivity of 93.2 (95% CI = 91–94) with 57.2 missed isolation days.ConclusionMulti-site screening is the optimal strategy for minimising MRSA exposure within a healthcare facility. For active MRSA surveillance, a combination of nasal and throat cultures can provide a practical approach in low-resource settings compared to nasal sampling alone.

Genomic Epidemiology of MRSA During Incarceration at a Large Inner-City Jail.

Congregate settings, such as jails, may be a location where colonized detainees transmit methicillin-resistant Staphylococcus aureus (MRSA). We examined MRSA acquisition during incarceration and characterized the genomic epidemiology of MRSA entering the jail and isolated during incarceration. Males incarcerated at the Cook County Jail were enrolled within 72 h of intake and MRSA surveillance cultures collected. Detainees in jail at Day 30 were re-cultured to determine MRSA acquisition. A survey was administered to identify acquisition predictors. Genomic sequencing of surveillance and clinical isolates was integrated with epidemiologic and jail location data to track MRSA transmission pathways. 800 males were enrolled; 19% MRSA colonized at intake. Of 184 who reached Day 30 visit, 12 acquired MRSA. Heroin use before entering (OR 3.67, P = .05) and sharing personal items during incarceration (OR = 4.92, P = .01) were predictors of acquisition. Sequenced clinical USA300 isolates (n = 112) were more genetically similar than diverse intake USA300 strains (P < .001), suggesting jail transmission. Four acquired colonization isolates were within 20 single-nucleotide variant (SNVs) of other isolates; 4 were within 20 SNVs of an intake isolate, 2 for an acquisition isolate, and 1 for a clinical isolate. Individuals with genetically similar isolates were more likely to have had overlapping stays in the same buildings. There was a high MRSA burden entering jail. Genomic analysis of acquisition and clinical isolates suggests potential spread of incoming strains and networks of spread during incarceration, with spread often occurring among detainees housed in similar locations. Sharing personal items during incarceration is associated with MRSA acquisition and could be a focus for intervention.

1035. Implementation of an Antimicrobial Stewardship Program-Led, Multifactorial Pneumonia Diagnosis and Treatment Bundle

BackgroundPneumonia remains a leading cause of hospitalization and accounts for significant antibiotic use. This study aims to evaluate the impact of bundled antimicrobial stewardship program (ASP) interventions, including procalcitonin and surveillance cultures, on broad-spectrum antimicrobial use in patients with suspected pneumonia.MethodsThis is a pre-post, quasi-experimental study conducted at Michigan Medicine. During the intervention period, an ASP member reviewed adult patients admitted to 3-floor medical services with antibiotics initiated for suspected pneumonia. The ASP member (1) recommended the use of procalcitonin when clinically appropriate, (2) used institutional guidelines to guide empiric antibiotic selection based on risk for drug-resistant pathogens, and (3) ordered a methicillin-resistant Staphylococcus aureus (MRSA) surveillance culture in patients receiving empiric anti-MRSA therapy. The primary endpoint was anti-MRSA and anti-pseudomonal (PSA) antibiotic use measured as days of therapy (DOT) per 1000 days-present on the services of interest. Antibiotic use and clinical data were extracted from an electronic database. Pneumonia diagnosis codes were used to identify the study population.ResultsA total of 549 patients were included: 310 in the pre-intervention (December 1/2017 - 3/31/2018) and 239 in the intervention (December 1/2018 - 3/31/2019) periods. Baseline demographics were similar between groups (Table 1). Less than 15% of patients had a microbiological diagnosis via respiratory culture in both study periods (Table 2). Respiratory cultures were ordered less commonly in the intervention period; however, the rate of culture positivity was higher (28% vs. 48%, P < 0.01). Process measures improved in the intervention period with an increase in the proportion of patients with MRSA surveillance cultures (13% vs. 39%, P < 0.01) and procalcitonin monitoring (77% vs. 83%, P = 0.07). Compared with the pre-intervention period, anti-MRSA antibiotic use decreased from 172 to 158 DOT per 1000 days-present (Δ -8%) and the use of anti-PSA antibiotics decreased from 348 to 316 DOT per 1000 days present (Δ -9%).ConclusionThe implementation of an ASP-led pneumonia bundle led to reductions in anti-MRSA and anti-PSA antibiotic use. Disclosures All authors: No reported disclosures.

Efficient processing of MRSA screening specimens by a modified inoculation protocol.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated infections and mortality, and therefore constitutes a serious cost factor in public health. Culture-based MRSA screening is a crucial part of MRSA-infection prevention and control strategies in the hospital setting. Manual inoculation of screening swabs onto culture plates still constitutes the major part of the technicians' workload in laboratories. We present a modified inoculation protocol that comprises direct inoculation of specimen onto a chromogenic MRSA-selective agar plate without further streaking for isolation. This study aims to evaluate the impact of this inoculation protocol on technicians' workload and the downstream workflow in our laboratory. Batches of 50 specimens were processed by different technicians and the hands-on time was compared between the standard and modified inoculation protocol. To assess the impact on downstream processing, a retrospective analysis of the rate of subcultures and turnaround time (TAT) of specimens yielding putative MRSA colonies from 9months before (n = 1548) and after (n = 1267) the protocol change was carried out based on laboratory information system (LIS) data. The implementation of the modified protocol significantly reduced technicians' hands-on time needed for inoculation by 26.5% without altering the overall turnaround time of surveillance cultures or causing higher costs for extra plates needed for subcultures. Our modified inoculation protocol offers a cost-effective and easy to implement procedure for MRSA surveillance cultures which significantly decreases technicians' workload and does not impede the downstream workflow. It therefore increases the capacity of laboratory technicians' to execute more demanding tasks.

The evaluation of MRSA surveillance cultures by the number and combinations of anatomical sites.

IntroductionThe identification of patients infected and/or colonised by methicillin resistant Staphylococcus aureus (MRSA) is necessary for the timely introduction of measures for infection control. We compared the diagnostic efficacy of combinations of MRSA surveillance swabs routinely taken by health institutions in the country.MethodsAll surveillance samples, which were sent for a microbiological analysis to detect MRSA with the culture method in 2014, in the three departments for medical microbiology of the National Laboratory for Health, Environment and Food, were included in this study.ResultsAmong 65,251 surveillance cultures from 13,274 persons, 1,233 (2.1%) were positive (490 positive persons). Prevailing positive surveillance cultures were throat swabs (31.3%), followed by nose swab (31.2%), skin swab (18.9%), perineum (16.4%) and wound swabs (1.4%). The contribution of other samples, such as aspirate, urine and excreta, was under 1%. We found no statistically significant differences in the frequency of detection of a positive patient, if the combination of samples NTS (nose, throat, skin) or NTP (nose, throat, perineum) was analysed. However, statistically significant differences were confirmed when any of the anatomic sites would be omitted from the sets of NTP and NTS (chi square; p<0.01). Adding additional samples resulted in only 24 additional positive patients (4.9%).ConclusionsThe results indicate that increasing the number of surveillance cultures above three does not add much to the sensitivity of MRSA surveillance, the exception could be wound. The swabs from the perineum and from the skin are exchangeable.

Transmission Clusters of Methicillin-Resistant Staphylococcus Aureus in Long-Term Care Facilities Based on Whole-Genome Sequencing.

OBJECTIVE To define how often methicillin-resistant Staphylococcus aureus (MRSA) is spread from resident to resident in long-term care facilities using whole-genome sequencing DESIGN Prospective cohort study SETTING A long-term care facility PARTICIPANTS Elderly residents in a long-term care facility METHODS Cultures for MRSA were obtained weekly from multiple body sites from residents with known MRSA colonization over 12-week study periods. Simultaneously, cultures to detect MRSA acquisition were obtained weekly from 2 body sites in residents without known MRSA colonization. During the first 12-week cycle on a single unit, we sequenced 8 MRSA isolates per swab for 2 body sites from each of 6 residents. During the second 12-week cycle, we sequenced 30 MRSA isolates from 13 residents with known MRSA colonization and 3 residents who had acquired MRSA colonization. RESULTS MRSA isolates from the same swab showed little genetic variation between isolates with the exception of isolates from wounds. The genetic variation of isolates between body sites on an individual was greater than that within a single body site with the exception of 1 sample, which had 2 unrelated strains among the 8 isolates. In the second cycle, 10 of 16 residents colonized with MRSA (63%) shared 1 of 3 closely related strains. Of the 3 residents with newly acquired MRSA, 2 residents harbored isolates that were members of these clusters. CONCLUSIONS Point prevalence surveys with whole-genome sequencing of MRSA isolates may detect resident-to-resident transmission more accurately than routine surveillance cultures for MRSA in long-term care facilities. Infect Control Hosp Epidemiol 2016;37:685-691.

Antibiogram of Methicillin-Resistant Staphylococcus aureus Isolates From MRSA Colonized Patients in Two Tertiary Hospital Emergency Departments

Background: Methicillin-Resistant Staphylococcus aureus (MRSA) colonized patients are at increased risk of developing MRSA infections. Objectives: This study was undertaken to evaluate the minimum inhibitory concentration (MIC) of anti-MRSA antibiotics for MRSA isolates from MRSA colonized patients. Patients and Methods: From November 2009 to March 2011, a prospective study was performed in two emergency departments. Patients at high risk for MRSA colonization were identified, and MRSA surveillance cultures obtained. The MIC for anti-MRSA antibiotics in cultures from each patient was evaluated. Results: A total of 276 patients were assessed. Of these, 23.6% (65/276) were MRSA culture positive. The MIC 50 and MIC 90 for vancomycin with these MRSA isolates by E-test were both 2 µg/mL. The MIC 50 and MIC 90 for teicoplanin were 2 µg/mL and 3 µg/mL, respectively, among MRSA isolates. Nearly all (62/65, 95.4%) MRSA isolates were sensitive to trimethoprim /sulfamethoxazole. Of all patients, 47.7% (31/65) of the MRSA isolates were sensitive to gentamicin, 40% (26/65) to minocycline, 13.8% (9/65) to clindamycin, 6.2% (4/65) to erythromycin, and 1.5% (1/65) to levofloxacin. Conclusions: The average value of the vancomycin MIC for isolates from MRSA colonized patients was 2 µg/ml. trimethoprim / sulfamethoxazole was the second most effective anti-MRSA oral antibiotic in vitro.

Duration of Colonization With Methicillin-Resistant Staphylococcus aureus: A Question With Many Answers

Duration of Colonization With Methicillin-Resistant Staphylococcus aureus: A Question With Many Answers

Duration of Colonization and Determinants of Earlier Clearance of Colonization With Methicillin-Resistant Staphylococcus aureus.

The duration of colonization and factors associated with clearance of methicillin-resistant Staphylococcus aureus (MRSA) after community-onset MRSA skin and soft-tissue infection (SSTI) remain unclear. We conducted a prospective cohort study of patients with acute MRSA SSTI presenting to 5 adult and pediatric academic hospitals from 1 January 2010 through 31 December 2012. Index patients and household members performed self-sampling for MRSA colonization every 2 weeks for 6 months. Clearance of colonization was defined as negative MRSA surveillance cultures during 2 consecutive sampling periods. A Cox proportional hazards regression model was developed to identify determinants of clearance of colonization. Two hundred forty-three index patients were included. The median duration of MRSA colonization after SSTI diagnosis was 21 days (95% confidence interval [CI], 19-24), and 19.8% never cleared colonization. Treatment of the SSTI with clindamycin was associated with earlier clearance (hazard ratio [HR], 1.72; 95% CI, 1.28-2.30; P < .001). Older age (HR, 0.99; 95% CI, .98-1.00; P = .01) was associated with longer duration of colonization. There was a borderline significant association between increased number of household members colonized with MRSA and later clearance of colonization in the index patient (HR, 0.85; 95% CI, .71-1.01; P = .06). With a systematic, regular sampling protocol, duration of MRSA colonization was noted to be shorter than previously reported, although 19.8% of patients remained colonized at 6 months. The association between clindamycin and shorter duration of colonization after MRSA SSTI suggests a possible role for the antibiotic selected for treatment of MRSA infection.

Prevalence of MRSA colonization in Japanese neonatal care unit patients in 2011

The neonatal intensive care unit (NICU) is a high-risk setting for transmission of methicillin-resistant Staphylococcus aureus (MRSA). The recent prevalence of colonization with MRSA in patients and its control measures are unknown in Japanese NICU. We investigated the prevalence of MRSA colonization in patients and measures to control and prevent health-care-associated transmission in Japanese NICU in 2011. A nationwide survey was performed in facilities certified as training hospitals for neonatologists. Data in NICU and growing care units (GCU) were collected and analyzed regarding surveillance cultures for MRSA and the proportion of MRSA-colonized patients in September 2011. Trends in the proportion of MRSA-colonized patients and the measures to control and prevent health-care-associated MRSA transmission were investigated in the surveyed NICU in 2000, 2003, and 2011. A total of 168 NICU and 158 GCU were analyzed. The proportions of NICU and GCU that conducted regular surveillance cultures for MRSA were 81% and 66%, respectively. MRSA colonization was not found in 53% of NICU and in 45% of GCU. The percentage of NICU reported to be free of MRSA colonization increased over time. Use of alcohol-based hand rub and gloves by clinical staff and cohorting for identified MRSA-positive patients became more common in 2011 than in 2000 or 2003. Approximately half of Japanese NICU did not observe any patients with MRSA colonization in September 2011. Control and prevention measures have changed to use of alcohol-based hand rub and gloves in the last decade.

Successful reduction of hospital-acquired methicillin-resistant Staphylococcus aureus in a urology ward: a 10-year study.

BackgroundTo eradicate hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) using a stepwise infection control strategy that includes an avoidance of antimicrobial prophylaxis (AMP) based on surgical wound classification and an improvement in operative procedures in gasless single-port urologic surgery.MethodsThe study was conducted at an 801-bed university hospital. Since 2001, in the urology ward, we have introduced the stepwise infection control strategy. In 2007, surveillance cultures for MRSA in all urological patients were commenced. The annual incidence of MRSA was calculated as a total number of newly identified MRSA cases per 1,000 patient days. Trend analysis was performed using a Poisson regression.ResultsOver the study period, 139,866 patients, including 10,201 urology patients, were admitted to our hospital. Of these patients, 3,719 patients, including 134 ones in the urology ward, were diagnosed with MRSA throughout the entire hospital. Although the incidence of MRSA increased throughout the entire hospital (p = 0.002), it decreased significantly in the urology ward (p < 0.0001). Of the 134 cases, 45 (33.6%) were classified as “imported,” and 89 (66.4%) as “acquired.” In the urology ward, the incidence of acquired MRSA decreased significantly over time (p < 0.0001), whereas the incidence of imported MRSA did not change over time (p = 0.66). A significant decrease (p < 0.0001) in the incidence of clinically significant MRSA infection over time was found.ConclusionsStepwise infection control strategy that includes a reduction or avoidance of antimicrobial prophylaxis in minimally invasive surgery can contribute to a reduction in hospital-acquired MRSA.Trial registrationCurrent study has approved by the institutional ethical review board (No.1141).

P054: Prevalence and risk factor analysis for methicillin-resistant Staphylococcus aureus colonization in an acute care hospital

Methicillin-resistant Staphylococcus aureus (MRSA) infections have been associated with increased mortality and hospital costs. Active surveillance cultures (ASCs) for MRSA and aggressive contact precautions have been shown to reduce MRSA transmission. Universal screening incurs financial and physical resources.

A Hidden Reservoir of Methicillin-resistant Staphylococcus aureus and Vancomycin-resistant Enterococcus in Patients Newly Admitted to an Acute Rehabilitation Hospital

To find hidden reservoirs of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) via active surveillance cultures for MRSA and VRE in newly admitted patients. A prospective, cohort, screening study. The period of surveillance was 3 months in the winter of 2006-2007. A freestanding academic and community rehabilitation hospital. A total of 540 consecutive patients admitted to a freestanding rehabilitation hospital. All of the patients were screened for MRSA and VRE upon admission to the hospital. The number of new patients identified with either MRSA or VRE colonization. A total of 540 patients were screened, of whom 42 (7.8%) had pre-existing MRSA status, 8 (1.5%) had pre-existing VRE status, and 10 (1.9%) had a history of positive results for both MRSA and VRE. Of the 480 patients without pre-existing positive cultures, admission swabs were positive for MRSA in 37 patients (7.7%), swabs were positive for VRE in 33 patients (6.9%), and swabs for both MRSA and VRE were newly positive for 7 patients (1.5%). Therefore 16% of the patients without a history of MRSA or VRE had a new finding of MRSA or VRE. Regression analysis revealed that prior bacteremia was a risk factor for MRSA; diabetes mellitus and a history of pneumonia and trimethoprim-sulfamethoxazole use were risk factors for VRE. We found a 16% incidence of a hidden reservoir of multiple drug-resistant organisms in patients admitted to rehabilitation hospitals. We believe that all patients admitted to a rehabilitation facility should be screened for MRSA and VRE.

Spread of Methicillin-ResistantStaphylococcus aureusin a Large Tertiary NICU: Network Analysis

Methicillin-resistant Staphylococcus aureus (MRSA) colonization in NICUs increases the risk of nosocomial infection. Network analysis provides tools to examine the interactions among patients and staff members that put patients at risk of colonization. Data from MRSA surveillance cultures were combined with patient room locations, nursing assignments, and sibship information to create patient- and unit-based networks. Multivariate models were constructed to quantify the risk of incident MRSA colonization as a function of exposure to MRSA-colonized infants in these networks. A MRSA-negative infant in the NICU simultaneously with a MRSA-positive infant had higher odds of becoming colonized when the colonized infant was a sibling, compared with an unrelated patient (odds ratio: 8.8 [95% confidence interval [CI]: 5.3-14.8]). Although knowing that a patient was MRSA-positive and was placed on contact precautions reduced the overall odds of another patient becoming colonized by 35% (95% CI: 20%-47%), having a nurse in common with that patient still increased the odds of colonization by 43% (95% CI: 14%-80%). Normalized group degree centrality, a unitwide network measure of connectedness between colonized and uncolonized patients, was a significant predictor of incident MRSA cases (odds ratio: 18.1 [95% CI: 3.6-90.0]). Despite current infection-control strategies, patients remain at significant risk of MRSA colonization from MRSA-positive siblings and from other patients with whom they share nursing care. Strategies that minimize the frequency of staff members caring for both colonized and uncolonized infants may be beneficial in reducing the spread of MRSA colonization.

Comparison of the Methicillin-Resistant Staphylococcus aureus Acquisition among Rehabilitation and Nursing Home Residents

To assess risk factors for methicillin-resistant Staphylococcus aureus (MRSA) acquisition among extended care residents focusing on level of care (residential vs rehabilitation) and room placement with an MRSA-positive resident. Prospective cohort study. Extended care units at 2 healthcare systems in Maryland. Four hundred forty-three residents with no history of MRSA and negative MRSA surveillance cultures of the anterior nares and areas of skin breakdown at enrollment. Follow-up cultures were collected every 4 weeks and/or at discharge for a period of 12 weeks. Study data were collected by a research nurse from the medical staff and the electronic medical records. Cox proportional hazards modeling was used to calculate adjusted hazards ratios (aHRs) and 95% confidence intervals (CIs). Residents in rehabilitation care had 4-fold higher risk of MRSA acquisition compared with residents in residential care (hazard ratio [HR], 4. [95% CI, 2.2-8.8]). Being bedbound was significantly associated with MRSA acquisition in both populations (residential care, aHR, 4.3 [95% CI, 1.5-12.2]; rehabilitation care, aHR, 4.8 [95% CI, 1.2-18.7]). Having an MRSA-positive roommate was not significantly associated with acquisition in either population (residential care, aHR, 1.4 [95% CI, 0.5-3.9]; rehabilitation care, aHR, 0.5 [95% CI, 0.1-2.2]); based on concordant spa typing, only 2 of 8 residents who acquired MRSA and had room placement with an MRSA-positive resident acquired their MRSA isolate from their roommate. Residents in rehabilitation care appear at higher risk and have different risk factors for MRSA acquisition compared to those in residential care.

Comparison of the Methicillin-Resistant Staphylococcus aureus Acquisition among Rehabilitation and Nursing Home Residents

Objective.To assess risk factors for methicillin-resistantStaphylococcus aureus(MRSA) acquisition among extended care residents focusing on level of care (residential vs rehabilitation) and room placement with an MRSA-positive resident.Design.Prospective cohort study.Setting.Extended care units at 2 healthcare systems in Maryland.Participants.Four hundred forty-three residents with no history of MRSA and negative MRSA surveillance cultures of the anterior nares and areas of skin breakdown at enrollment.Methods.Follow-up cultures were collected every 4 weeks and/or at discharge for a period of 12 weeks. Study data were collected by a research nurse from the medical staff and the electronic medical records. Cox proportional hazards modeling was used to calculate adjusted hazards ratios (aHRs) and 95% confidence intervals (CIs).Results.Residents in rehabilitation care had 4-fold higher risk of MRSA acquisition compared with residents in residential care (hazard ratio [HR], 4. [95% CI, 2.2-8.8]). Being bedbound was significantly associated with MRSA acquisition in both populations (residential care, aHR, 4.3 [95% CI, 1.5-12.2]; rehabilitation care, aHR, 4.8 [95% CI, 1.2-18.7]). Having an MRSA-positive roommate was not significantly associated with acquisition in either population (residential care, aHR, 1.4 [95% CI, 0.5-3.9]; rehabilitation care, aHR, 0.5 [95% CI, 0.1-2.2]); based on concordantspatyping, only 2 of 8 residents who acquired MRSA and had room placement with an MRSA-positive resident acquired their MRSA isolate from their roommate.Conclusion.Residents in rehabilitation care appear at higher risk and have different risk factors for MRSA acquisition compared to those in residential care.

Prevalence of and risk factors for methicillin-resistant Staphylococcus aureus colonization and infection among infants at a level III neonatal intensive care unit

Methicillin-resistant Staphylococcus aureus (MRSA) is a well-known nosocomial pathogen of neonatal intensive care unit (NICU) patients and can cause both serious infections in preterm neonates and prolonged MRSA outbreaks in NICUs. Our objectives were to determine the prevalence of and identify risk factors for MRSA colonization and infection in the NICU and the impact of an active surveillance program on MRSA in the NICU. We collected weekly nasal MRSA surveillance cultures on 2,048 infants admitted to NICU over 3 years. Data on these infants were collected retrospectively. Characteristics of MRSA colonized and infected infants were analyzed and compared. MRSA colonization was detected in 6.74% of infants, and MRSA infection occurred in 22% of those colonized. Using clinical cultures alone, only 41 (27.5%) of 149 MRSA affected infants were identified. The majority (75%) developed MRSA infection within 17 days of colonization. For every 10-day increment in NICU stay, the odds ratio of being infected and colonized with MRSA increased by 1.32 and 1.29, respectively. Colonization was significantly associated with longer NICU stay, low birth weight, low gestational age, and multiple gestation status. Colonization is a risk factor for infection with MRSA in NICUs. Clinical cultures underestimate MRSA affected infants in NICUs, whereas active surveillance cultures could detect MRSA affected infants earlier and limit nosocomial spread.

Carriage rates of methicillin-resistant Staphylococcus aureus (MRSA) depend on anatomic location, the number of sites cultured, culture methods, and the distribution of clonotypes

The present study was carried out to determine how active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) could be improved by the use of enrichment broth and the inclusion of extra-nasal sites with nares cultures. Molecular typing was also performed to identify colonization by single or multiple strains. Surveillance cultures for MRSA were obtained from 650 patients on admission to a medical and surgical intensive care unit (ICU) in Taiwan. MRSA was detected on directly plated vs. broth-enrichment cultures in any site at 10.0% vs. 24.2%, nares 8.2% vs. 17.5%, throat 4.8% vs. 13.4%, axilla 1.2% vs. 9.1%, and perineum 1.8% vs. 9.5%, respectively. Nares cultures alone detected only 81.5% and 72.5% of all colonized patients by direct and broth-enriched cultures, respectively. The molecular typing of 68 isolates from 17 patients revealed that multisite isolates were largely indistinguishable within each patient, but four patients had multiple subtypes and another three patients had different clonotypes. The detection of MRSA carriers was considerably enhanced by broth-enrichment cultures at multiple anatomic sites and simultaneous colonization by multiple strains at different sites can occur. Epidemiological studies are needed to determine the likelihood of subsequent nosocomial infection among colonized patients detected via direct nasal versus broth-enriched cultures from multiple sites.

The Effectiveness of Chlorhexidine bath in the prevention of Methicillin Resistant Staphylococcus Aureus (MRSA) in the Adult inpatient wards. A systematic review.

Review question/objective Objectives: Primary 1) To evaluate the effectiveness of chlorhexidine bath in eradicating MRSA carriage. 2) To evaluate the efficacy of chlorhexidine bath on MRSA incidence rate in the adult inpatient wards. 3) To evaluate the effectiveness of chlorhexidine bathing with or without topical decolonization therapy in reducing risk of MRSA infection among MRSA colonized inpatients. Secondary: 1) To evaluate the development of MRSA infection and tolerance to chlorhexidine bath with or without topical decolonization therapy. 2) To assess the effectiveness of chlorhexidine bath on the rates of Blood Stream Infections (BSI). Review Questions: 1) Can chlorhexidine bath reduce the acquisition rate of MRSA during their hospitalisation? 2) Is the use of chlorhexidine more effective in preventing incidence of MRSA than soap and water? 3) Is the combination of chlorhexidine bath and decolonization therapy more effective in the eradicating MRSA than chlorhexidine bath alone? 4) Can Chlorhexidine bath alone decrease blood stream infection? Inclusion criteria Types of participants - Adults over age of 18 - Both Female and Male - Admitted to inpatient adult wards - Admitted with MRSA surveillance screening swab cultures performed on the following screening sites: nasal nares, axilla and groin on admission prior to treatment. (Patient who have MRSA surveillance cultures done on admission and results shows to be infected or colonised) Types of intervention(s)/phenomena of interest The use of chlorhexidine shower/bath/wipes/wash with or without combination of other pharmacological therapies such as antibiotics, topical decolonisation therapy for MRSA. The various administration methods, duration and frequency will be included in the review. Types of Comparator The comparator group includes no chlorhexidine shower (usual care with soap and water), with or without antibiotics or topical decolonisation therapy. Types of outcomes The outcomes of interest include: 1) Development of MRSA infection: Objective or subjective indicators of MRSA infection: Culture results or clinical evidence of infections 2) Eradication of MRSA carriage using chlorhexidine shower/bath/wipes/wash Outcome: 1) The duration and the frequency of the use of daily chlorhexidine shower to eradicate skin and nasal carriage of MRSA & preventing colonisation. 2) Comparative Benefits of combination therapy with chlorhexidine shower with decolonisation therapy vs. chlorhexidine shower only. 3) Tolerance to chlorhexidine shower with or without decolonisation therapy. 4) Blood stream infection (with or without MRSA)

Active Surveillance to Determine the Impact of Methicillin-Resistant Staphylococcus aureus Colonization on Patients in Intensive Care Units of a Veterans Affairs Medical Center

The impact of methicillin-resistant Staphylococcus aureus (MRSA) colonization on mortality has not been well characterized. We sought to describe the impact of MRSA colonization on patients admitted to intensive care units (ICUs) in the Birmingham Veterans Affairs Medical Center (VAMC). We conducted a retrospective cohort study of ICU patients at the Birmingham VAMC during 2005 to evaluate the predictors of MRSA colonization and determine its effect on clinical outcomes. Surveillance cultures for MRSA were performed on admission to the ICU and weekly thereafter. Clinical findings, the incidence of MRSA infection, and mortality within 3 months after ICU admission were recorded. Predictors of mortality and S. aureus colonization were determined using multivariable models. S. aureus colonization was present in 97 (23.3%) of 416 patients screened, of whom 67 (16.1%) were colonized with methicillin-susceptible S. aureus (MSSA) and 30 (7.2%) with MRSA. All-cause mortality at 3 months among MRSA-colonized patients was significantly greater than that among MSSA-colonized patients (46.7% vs 19.4%; P = .009). MRSA colonization was an independent predictor of death (adjusted odds ratio [OR], 3.7 [95% confidence interval [CI], 1.5-8.9]; P = .003) and onset of MRSA infection after hospital discharge (adjusted OR, 7.6 [95% CI, 2.48-23.2]; P < .001). Risk factors for MRSA colonization included recent antibiotic use (adjusted OR, 4.8 [95% CI, 1.9-12.2]; P = .001) and dialysis (adjusted OR, 18.9 [95% CI, 2.1-167.8]; P = .008). Among ICU patients, MRSA colonization is associated with subsequent MRSA infection and an all-cause mortality that is greater than that for MSSA colonization. Active surveillance for MRSA colonization may identify individuals at risk for these adverse outcomes. Prospective studies of outcomes in MRSA-colonized patients may better define the role of programs for active MRSA surveillance.