Risk factors for methicillin-resistant Staphylococcus aureus (MRSA) acquisition in roommate contacts of patients colonized or infected with MRSA in an acute-care hospital

Effectiveness of methicillin-resistant Staphylococcus aureus surveillance among exposed roommates in community hospitals: Conventional culture versus direct PCR

BACKGROUND

Roommates of unrecognized nosocomial methicillin-resistant Staphylococcus aureus (MRSA) cases are at a higher acquisition risk; however, optimal surveillance strategies are unknown.

METHODS

Using simulation, we analyzed surveillance testing and isolation strategies for MRSA among exposed hospital roommates. We compared isolating exposed roommates until conventional culture testing on day 6 and a nasal polymerase chain reaction test on day 3 (PCR3) with/without day 0 culture testing (Cult0). The model represents MRSA transmission in medium-sized hospitals using data and recommends best practices from the literature and Ontario community hospitals.

RESULTS

Cult0 + PCR3 incurred a slightly lower number of MRSA colonizations and 38.9% lower annual cost in the base case compared to Cult0 + culture testing on day 6 because the reduced isolation cost compensated for the increased testing cost. The reduction in MRSA colonizations was due to a 54.5% drop in MRSA transmissions during isolation as PCR3 reduced the exposure of MRSA-free roommates to new MRSA carriers. Removing the day 0 culture test from Cult0 + PCR3 increased total cost, the number of MRSA colonization, and missed cases by $1,631, 4.3%, and 50.9%, respectively. Improvements were higher under aggressive MRSA transmission scenarios.

DISCUSSION AND CONCLUSIONS

Adopting direct nasal polymerase chain reaction testing for determining post-exposure MRSA status reduces transmission risk and costs. Day 0 culture would still be beneficial.

Comparative Genomics Identifies Features Associated with Methicillin-Resistant Staphylococcus aureus (MRSA) Transmission in Hospital Settings

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious public health concern in the United States. Patients colonized and/or infected can transmit MRSA to healthcare workers and subsequent patients However, the components of this transmission chain are just becoming evident, including certain patient factors, specific patient-healthcare worker interactions, and microbial factors. We conducted a comparative genomic analysis of 388 isolates from four hospitals in three states: Maryland, California, and New York. Isolates from nasal surveillance or clinical cultures were categorized as high, moderate, or low transmission surrogate outcomes based on the number of times the species was identified on the gloves or gowns of healthcare providers. The comparative analyses included a single gene, multigene, and core genome phylogenetic analysis, as well as a genome-wide association analysis to identify molecular signatures associated with the observed transmission surrogate outcomes, geographic origin, or sample source of isolation. Based on the phylogenetic analysis, 95% (n = 372) of the MRSA isolates were from four well-described genomic clades, with most of the isolates being part of the USA300 containing clade (n = 187; 48%). Genome-wide association studies also identified genes that were exclusive or prevalent among specific geographic locations. The identified genes provide insights into the transmission dynamics of MRSA isolates providing additional insights into the basis of the geographical differences of MRSA for molecular diagnostics. IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) is considered a serious threat to public health and contributes to the dissemination of S. aureus in both the healthcare and community setting. Transmission of MRSA between patients via healthcare worker (HCW) has been described. However, what is not understood are the genetic determinants that contribute to the transmission of MRSA from patients to HCWs. In this study, we demonstrated that certain genes may be associated with transmission in the hospital setting.

Community-associated Methicillin-resistant Staphylococcus aureus pericarditis in an immunocompetent patient

Background

Pericarditis caused by Methicillin-resistant Staphylococcus aureus (MRSA) is a rare infection, often seen in patients with chronic kidney disease, immunosuppression, or previous pericardial disease. The presentation can be dramatic with acute illness leading to septic and/or obstructive shock due to pericardial tamponade. Occasionally disease can have a more protracted, indolent, subacute clinical course.

Case report

We report a case of a 57-year-old male patient with a previous history of smoking and moderate alcohol use who presented with progressive dyspnea and cough. He was found to have a disseminated MRSA infection with pericarditis complicated by pericardial tamponade. Urgent pericardiocentesis yielded 1.1 liters of purulent fluid that grew MRSA. MRSA was also isolated from the blood and pleural fluid. The patient underwent left thoracotomy, decortication, and pericardial window and completed 3 weeks of intravenous vancomycin therapy, concluding in an excellent outcome.

Conclusion

Bacterial pericarditis is an exceptionally rare form of pericarditis which been traditionally associated with chronic medical conditions requiring a prolonged healthcare stay. However, it has lately been observed in healthy individuals with social habits such as smoking and alcohol consumption. Bacterial pericarditis must be recognized in a timely fashion and managed aggressively to prevent a devastating outcome. A multidisciplinary approach is advised, which includes a combination of pericardial drainage and aggressive antibiotic therapy. Such treatment often yields a positive outcome and good long-term prognosis.

Import of multidrug-resistant bacteria from abroad through interhospital transfers, Finland, 2010-2019

Background

While 20–80% of regular visitors to (sub)tropical regions become colonised by extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE), those hospitalised abroad often also carry other multidrug-resistant (MDR) bacteria on return; the rates are presumed to be highest for interhospital transfers.

Aim

This observational study assessed MDR bacterial colonisation among patients transferred directly from hospitals abroad to Helsinki University Hospital. We investigated predisposing factors, clinical infections and associated fatalities.

Methods

Data were derived from screening and from diagnostic samples collected between 2010 and 2019. Risk factors of colonisation were identified by multivariable analysis. Microbiologically verified symptomatic infections and infection-related mortality were recorded during post-transfer hospitalisation.

Results

Colonisation rates proved highest for transfers from Asia (69/96; 71.9%) and lowest for those within Europe (99/524; 18.9%). Of all 698 patients, 208 (29.8%) were colonised; among those, 163 (78.4%) carried ESBL-PE, 28 (13.5%) MDR Acinetobacter species, 25 (12.0%) meticillin-resistant Staphylococcus aureus, 25 (12.0%) vancomycin-resistant Enterococcus, 14 (6.7%) carbapenemase-producing Enterobacteriaceae, and 12 (5.8%) MDR Pseudomonas aeruginosa; 46 strains tested carbapenemase gene-positive. In multivariable analysis, geographical region, intensive care unit (ICU) treatment and antibiotic use abroad proved to be risk factors for colonisation. Clinical MDR infections, two of them fatal (1.0%), were recorded for 22 of 208 (10.6%) MDR carriers.

Conclusions

Colonisation by MDR bacteria was common among patients transferred from foreign hospitals. Region of hospitalisation, ICU treatment and antibiotic use were identified as predisposing factors. Within 30 days after transfer, MDR colonisation manifested as clinical infection in more than 10% of the carriers.

Risk factors for colonization and infection by resistant microorganisms in kidney transplant recipients

OBJECTIVES

to assess the prevalence of colonization and infection by multidrug-resistant bacteria in patients undergoing kidney transplantation and identify the rate of infection, morbidity and mortality and associated risk factors.

METHODS

a prospective cohort of 200 randomly included kidney transplant recipients. Epidemiological surveillance of the studied microorganisms was carried out in the first 24 hours and 7 days after transplantation.

RESULTS

ninety (45%) patients were considered colonized. Female sex, hypertension and diabetes (p<0.005), dialysis time (p<0.004), length of stay after transplantation, delayed renal function, and length of stay were identified as risk factors. The microorganisms were isolated from surgical site, bloodstream and urinary tract infections.

CONCLUSIONS

colonization by resistant microorganisms in kidney transplant patients was frequent and risk factors associated with infection were identified. The results should guide the care team in order to minimize morbidity and mortality related to infectious causes in this population.

Ward-level factors associated with methicillin-resistant Staphylococcus aureus acquisition-an electronic medical records study in Singapore

Background

Methicillin-Resistant Staphylococcus aureus (MRSA) is endemic in hospitals worldwide. Intrahospital transfers may impact MRSA acquisition risk experienced by patients. In this study, we investigated ward characteristics and connectivity that are associated with MRSA acquisition.

Methods

We analysed electronic medical records on patient transfers and MRSA screening of in-patients at an acute-care tertiary hospital in Singapore to investigate whether ward characteristics and connectivity within a network of in-patient wards were associated with MRSA acquisition rates over a period of four years.

Results

Most patient transfers concentrated in a stable core network of wards. Factors associated with increased rate of MRSA acquisition were MRSA prevalence among patients transferred from other wards (rate ratio (RR): 7.74 [95% confidence interval (CI): 3.88, 15.44], additional 5 percentage point), critical care ward (RR: 1.72 [95% CI: 1.09, 2.70]) and presence of MRSA cohorting beds (RR: 1.39 [95% CI: 1.03, 1.90]. Oncology ward (RR: 0.66 [95% CI: 0.46, 0.94]) (compared to medical ward), and median length of stay (RR: 0.70 [95% CI: 0.55, 0.90], additional 1.5 days) were associated with lower acquisition rates. In addition, we found evidence of interaction between MRSA prevalence among patients transferred from other wards and weighted in-degree although the latter was not associated with MRSA acquisition after controlling for confounders.

Conclusion

Wards with higher MRSA prevalence among patients transferred from other wards were more likely to have higher MRSA acquisition rate. Its effect further increased in wards receiving greater number of patients. In addition, critical care ward, presence of MRSA cohorting beds, ward specialty, and median length of stay were associated with MRSA acquisition.

Not too close! impact of roommate status on MRSA and VRE colonization and contamination in Nursing Homes

Multiple room occupancy is common in Nursing Homes (NHs), and its role in transmission of antibiotic-resistant pathogens is unclear. We investigated prevalence of patient colonization and environmental contamination with vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) in NH roommates, compared it with expected prevalence, and determined specific body and environmental sites that may act as sources of roommate colonization. Roommate contamination was associated with index patient's colonization (relative risk (RR): 2.57 (95% CI 1.04-6.37)) for MRSA, and index patient's immediate environment contamination for VRE (RR: 3.60 (95% CI 1.59-8.12)). When specific index patient sites associated with roommate colonization were investigated, the side table (Fisher's p = 0.029 and 0.047 for VRE and MRSA, respectively) and the nurse call button (p = 0.001 and 0.052) stood out, together with patient hands in the case of VRE (p = 0.026). Future studies should be carried out to establish whether these sites should be a specific target of infection prevention campaigns in NHs with multiple occupancy rooms.

The effect of isolation precautions on care processes and medical outcomes in patients colonized with MRSA

Background: Isolation precautions used in methicillin-resistant Staph ylo coc cus aureus (MRSA) infection control are effective in inhibiting pathogen transmission, but may cause unintended consequences in medical care. In addition, while costs attributed to MRSA are known to be substantial, little is known about their reimbursement in the German Diagnosis Related Groups (G-DRG) payment system. The aim of our study was to examine the effect of isolation precautions used in MRSA infection control on care processes, patient outcomes and deliver reliable data on MRSA-attributed reimbursement. Methods: A retrospective, matched cohort study of inpatients admitted to a general care teaching hospital in Bad Neuenahr, Germany, between January 1st, 2016, and December 31st, 2017 was performed. Patients isolated for MRSA colonization were matched to non-isolated controls based on age, gender, MRSA-adjusted Patient Clinical Complexity Level (Ma-PCCL) and Major Diagnostic Category (MDC). Main outcome measures on care processes and patient outcomes included adverse events, patient complaints, 30-day readmission rates, length of stay, type of discharge, and performance of instrument-based diagnostics. MRSA-attributed reimbursement was measured by conducting two separate G-DRG groupings, one with inclusion of MRSA-related codes and one without. Results: A total of 26,059 patients were admitted to Maria Hilf Hospital in Bad Neuenahr, Germany, during the study period. We identified 304 patients isolated for MRSA colonization. Compared to non-isolated matched controls, those on isolation precautions for MRSA colonization acquired about 45% more pressure ulcers and experienced significant delays in the performance of radiological diagnostics and echocardiographs. Patients isolated for MRSA colonization received about 49% fewer echocardiographs and had about 38% fewer abdominal ultrasound exams performed compared to non-isolated matched controls. A non-significant tendency towards fewer discharges to rehabilitation clinics and higher mortality rates were observed in patients isolated for MRSA colonization. Reimbursements were negligibly affected when MRSA-related codes were integrated by the grouper. Conclusion: Isolation precautions are associated with adverse consequences for care processes. These consequences need to be mitigated in order to justify placing patients at risk.

Transmission pathways of multidrug-resistant organisms in the hospital setting: a scoping review

BACKGROUND

Prevalence of multidrug-resistant microorganisms (MDROs) continues to increase, while infection control gaps in healthcare settings facilitate their transmission between patients. In this setting, 5 distinct yet interlinked pathways are responsible for transmission. The complete transmission process is still not well understood. Designing and conducting a single research study capable of investigating all 5 complex and multifaceted pathways of hospital transmission would be costly and logistically burdensome. Therefore, this scoping review aims to synthesize the highest-quality published literature describing each of the 5 individual potential transmission pathways of MDROs in the healthcare setting and their overall contribution to patient-to-patient transmission.

METHODS

In 3 databases, we performed 2 separate systematic searches for original research published during the last decade. The first search focused on MDRO transmission via the HCW or the environment to identify publications studying 5 specific transmission pathways: (1) patient to HCW, (2) patient to environment, (3) HCW to patient, (4) environment to patient, and (5) environment to HCW. The second search focused on overall patient-to-patient transmission regardless of the transmission pathway. Both searches were limited to transmission of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus, multidrug-resistant A. baumannii, and carbapenem-resistant Enterobacteriaceae. After abstract screening of 5,026 manuscripts, researchers independently reviewed and rated the remaining papers using objective predefined criteria to identify the highest quality and most influential manuscripts.

RESULTS

High-quality manuscripts were identified for all 5 routes of transmission. Findings from these studies were consistent for all pathways; however, results describing the routes from the environment/HCW to a noncolonized patient were more limited and variable. Additionally, most research focused on MRSA, instead of other MDROs. The second search yielded 10 manuscripts (8 cohort studies) that demonstrated the overall contribution of patient-to-patient transmission in hospitals regardless of the transmission route. For MRSA, the reported cross-transmission was as high as 40%.

CONCLUSIONS

This scoping review brings together evidence supporting all 5 possible transmission pathways and illustrates the complex nature of patient-to-patient transmission of MDROs in hospitals. Our findings also confirm that transmission of MDROs in hospitals occurs frequently, suggesting that ongoing efforts are necessary to strengthen infection prevention and control to prevent the spread of MDROs.

A Discrete Event Simulation Model of Patient Flow in a General Hospital Incorporating Infection Control Policy for Methicillin-Resistant Staphylococcus Aureus (MRSA) and Vancomycin-Resistant Enterococcus (VRE)

BACKGROUND

Hospitalized patients are assigned to available staffed beds based on patient acuity and services required. In hospitals with double-occupancy rooms, patients must be additionally matched by gender. Patients with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) must be bedded in single-occupancy rooms or cohorted with other patients with similar MRSA/VRE flags.

METHODS

We developed a discrete event simulation (DES) model of patient flow through an acute care hospital. Patients are matched to beds based on acuity, service, gender, and known MRSA/VRE colonization. Outcomes included time to bed arrival, length of stay, patient-bed acuity mismatches, occupancy, idle beds, acuity-related transfers, rooms with discordant MRSA/VRE colonization, and transmission due to discordant colonization.

RESULTS

Observed outcomes were well-approximated by model-generated outcomes for time-to-bed arrival (6.7 v. 6.2 to 6.5 h) and length of stay (3.3 v. 2.9 to 3.0 days), with overlapping 90% coverage intervals. Patient-bed acuity mismatches, where patient acuity exceeded bed acuity and where patient acuity was lower than bed acuity, ranged from 0.6 to 0.9 and 8.6 to 11.1 mismatches per h, respectively. Values for observed occupancy, total idle beds, and acuity-related transfers compared favorably to model-predicted values (91% v. 86% to 87% occupancy, 15.1 v. 14.3 to 15.7 total idle beds, and 27.2 v. 22.6 to 23.7 transfers). Rooms with discordant colonization status and transmission due to discordance were modeled without an observed value for comparison. One-way and multi-way sensitivity analyses were performed for idle beds and rooms with discordant colonization.

CONCLUSIONS

We developed and validated a DES model of patient flow incorporating MRSA/VRE flags. The model allowed for quantification of the substantial impact of MRSA/VRE flags on hospital efficiency and potentially avoidable nosocomial transmission.

Characterizing non-linear effects of hospitalisation duration on antimicrobial resistance in respiratory isolates: an analysis of a prospective nationwide surveillance system

OBJECTIVES

Our objective was to systematically study the influence of length of hospital stay on bacterial resistance in relevant respiratory tract isolates.

METHODS

Using prospective epidemiological data from the National Swiss Antibiotic Resistance Surveillance System, susceptibility testing results for respiratory isolates retrospectively retrieved from patients hospitalised between 2008 and 2014 were compiled. Generalized additive models were used to illustrate resistance rates relative to hospitalisation duration and to adjust for co-variables.

RESULTS

In all, 19 622 isolates of six relevant and predominant species were included. Resistance patterns for the predominant species showed a species-specific and antibiotic-resistance-specific profile in function of hospitalisation duration. The oxacillin resistance profile in Staphylococcus aureus isolates was constantly increasing (monophasic). The pattern of resistance to cefepime in Pseudomonas aeruginosa was biphasic with a decreasing resistance rate for the first 5 days of hospitalisation and an increase for days 6-30. A different biphasic pattern occurred in Escherichia coli regarding amoxicillin-clavulanic acid resistance: odds/day increased for the first 7 days of hospitalisation and then remained stable for days 8-30. In the adjusted models epidemiological characteristics such as age, ward type, hospital type and linguistic region were identified as relevant co-variables for the resistance rates. The contribution of these confounders was specific to the individual species/antibiotic resistance models.

CONCLUSIONS

Resistance rates do not follow a dichotomic pattern (early versus late nosocomial) as suggested by current hospital-acquired pneumonia treatment guidelines. Duration of hospitalisation rather appears to have a more complex and non-linear relationship with bacterial resistance in hospital-acquired pneumonia, also depending on host and environmental factors.

Role of Human Factors Engineering in Infection Prevention: Gaps and Opportunities

Human factors engineering (HFE), with its focus on studying how humans interact with systems, including their physical and organizational environment, the tools and technologies they use, and the tasks they perform, provides principles, tools, and techniques for systematically identifying important factors, for analyzing and evaluating how these factors interact to increase or decrease the risk of Healthcare-associated infections (HAI), and for identifying and implementing effective preventive measures. We reviewed the literature on HFE and infection prevention and control and identified major themes to document how researchers and infection prevention staff have used HFE methods to prevent HAIs and to identify gaps in our knowledge about the role of HFE in HAI prevention and control. Our literature review found that most studies in the healthcare domain explicitly applying (HFE) principles and methods addressed patient safety issues not infection prevention and control issues. In addition, most investigators who applied human factors principles and methods to infection prevention issues assessed only one human factors element such as training, technology evaluations, or physical environment design. The most significant gap pertains to the limited use and application of formal HFE tools and methods. Every infection prevention study need not assess all components in a system, but investigators must assess the interaction of critical system components if they want to address latent and deep-rooted human factors problems.

Acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in contacts of patients newly identified as colonized or infected with MRSA in the immediate postexposure and postdischarge periods

The acquisition of methicillin-resistant Staphylococcus aureus (MRSA) after exposure to patients colonized or infected with MRSA was assessed. Among contacts with complete surveillance screening, the rate of acquisition was 5.7% and was lower in those identified postdischarge (17/683, 2.5%) compared with those tested in the immediate postexposure period (62/706, 8.8%).

Methicillin-Resistant Staphylococcus aureus Pneumonia in Critically Ill Trauma and Burn Patients: A Retrospective Cohort Study

BACKGROUND

The timing and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) pneumonia in trauma patients are not well characterized. This information is critical for the selection of appropriate empiric antibiotics. The objective of this study was to determine the incidence of MRSA pneumonia in early-onset and late-onset pneumonia and to identify risk factors for MRSA in the trauma-burn intensive care unit (ICU).

PATIENTS AND METHODS

We conducted a retrospective cohort study from January 2012 to March 2015 of patients in the trauma and burn ICU with clinical and microbiologic evidence of pneumonia. Demographics, injury type and severity, co-morbidities, antimicrobial agents, and MRSA nasal colonization at ICU admission were extracted from the medical record. A multi-variable exact logistic regression was performed to assess predictors of MRSA pneumonia.

RESULTS

Eighty patients with 88 episodes of pneumonia were included in the cohort. Ten patients had MRSA pneumonia, an overall incidence of 11.4% of pneumonia episodes with a median onset of seven days. The proportion of MRSA pneumonia episodes was not significantly different in early-onset (<5 days) or late-onset pneumonia, and there were no statistically significant risk factors for developing MRSA pneumonia. The majority of patients with MRSA had at least one known risk factor including homelessness, substance abuse, and receipt of broad-spectrum antibiotic agents.

CONCLUSIONS

The 11.4% overall incidence of MRSA pneumonia in this trauma-burn cohort was similar to what has been reported in other trauma populations, although MRSA was equally likely to be identified in early- and late-onset pneumonia. Our results suggest that risk factors other than duration of hospitalization may be important considerations in the decision to initiate MRSA-active empiric therapy for pneumonia in the trauma-burn ICU.

Transmission of Staphylococcus aureus between health-care workers, the environment, and patients in an intensive care unit: a longitudinal cohort study based on whole-genome sequencing

Background

Health-care workers have been implicated in nosocomial outbreaks of Staphylococcus aureus, but the dearth of evidence from non-outbreak situations means that routine health-care worker screening and S aureus eradication are controversial. We aimed to determine how often S aureus is transmitted from health-care workers or the environment to patients in an intensive care unit (ICU) and a high-dependency unit (HDU) where standard infection control measures were in place.

Methods

In this longitudinal cohort study, we systematically sampled health-care workers, the environment, and patients over 14 months at the ICU and HDU of the Royal Sussex County Hospital, Brighton, England. Nasal swabs were taken from health-care workers every 4 weeks, bed spaces were sampled monthly, and screening swabs were obtained from patients at admission to the ICU or HDU, weekly thereafter, and at discharge. Isolates were cultured and their whole genome sequenced, and we used the threshold of 40 single-nucleotide variants (SNVs) or fewer to define subtypes and infer recent transmission.

Findings

Between Oct 31, 2011, and Dec 23, 2012, we sampled 198 health-care workers, 40 environmental locations, and 1854 patients; 1819 isolates were sequenced. Median nasal carriage rate of S aureus in health-care workers at 4-weekly timepoints was 36·9% (IQR 35·7–37·3), and 115 (58%) health-care workers had S aureus detected at least once during the study. S aureus was identified in 8–50% of environmental samples. 605 genetically distinct subtypes were identified (median SNV difference 273, IQR 162–399) at a rate of 38 (IQR 34–42) per 4-weekly cycle. Only 25 instances of transmission to patients (seven from health-care workers, two from the environment, and 16 from other patients) were detected.

Interpretation

In the presence of standard infection control measures, health-care workers were infrequently sources of transmission to patients. S aureus epidemiology in the ICU and HDU is characterised by continuous ingress of distinct subtypes rather than transmission of genetically related strains.

Funding

UK Medical Research Council, Wellcome Trust, Biotechnology and Biological Sciences Research Council, UK National Institute for Health Research, and Public Health England.

Community- and Healthcare-Associated Methicillin-Resistant Staphylococcus aureus Strains: An Investigation Into Household Transmission, Risk Factors, and Environmental Contamination

OBJECTIVE To measure transmission frequencies and risk factors for household acquisition of community-associated and healthcare-associated (HA-) methicillin-resistant Staphylococcus aureus (MRSA). DESIGN Prospective cohort study from October 4, 2008, through December 3, 2012. SETTING Seven acute care hospitals in or near Toronto, Canada. PARTICIPANTS Total of 99 MRSA-colonized or MRSA-infected case patients and 183 household contacts. METHODS Baseline interviews were conducted, and surveillance cultures were collected monthly for 3 months from household members, pets, and 8 prespecified high-use environmental locations. Isolates underwent pulsed-field gel electrophoresis and staphylococcal cassette chromosome mec typing. RESULTS Overall, of 183 household contacts 89 (49%) were MRSA colonized, with 56 (31%) detected at baseline. MRSA transmission from index case to contacts negative at baseline occurred in 27 (40%) of 68 followed-up households. Strains were identical within households. The transmission risk for HA-MRSA was 39% compared with 40% (P=.95) for community-associated MRSA. HA-MRSA index cases were more likely to be older and not practice infection control measures (P=.002-.03). Household acquisition risk factors included requiring assistance and sharing bath towels (P=.001-.03). Environmental contamination was identified in 78 (79%) of 99 households and was more common in HA-MRSA households. CONCLUSION Household transmission of community-associated and HA-MRSA strains was common and the difference in transmission risk was not statistically significant. Infect Control Hosp Epidemiol 2016;1-7.

Prophylactic treatment of chronic renal disease in patients undergoing peritoneal dialysis and colonized by Staphylococcus aureus: a systematic review and meta-analysis

BACKGROUND

This study was performed to evaluate the clinical effectiveness of alternative strategies for the prevention and treatment of patients with chronic kidney disease undergoing peritoneal dialysis and colonized by Staphylococcus aureus.

METHODS

A systematic review and meta-analysis were performed. The literature search involved the following databases: the Cochrane Controlled Trials Register, Embase, LILACS, CINAHL, SciELO, and PubMed/Medline. The descriptors were "Staphylococcus aureus," "MRSA," "MSSA," "treatment," "decolonization," "nasal carrier," "colonization," "chronic kidney disease," "dialysis," and "peritoneal dialysis." Randomized controlled trials that exhibited agreement among reviewers as shown by a kappa value of >0.80 were included in the study; methodological quality was evaluated using the STROBE statement. Patients who received various antibiotic treatments (antibiotic group) or topical mupirocin (mupirocin group) were compared with those who received either no treatment or placebo (control group). Patients in the antibiotic group were also compared with those in the mupirocin group.

RESULTS

In total, nine studies involving 839 patients were included in the analysis, 187 (22.3 %) of whom were nasal carriers of S. aureus. The probability of S. aureus infection at the catheter site for peritoneal dialysis was 74 % lower in the mupirocin than control group (odds ratio [OR], 0.26; 95 % confidence interval [CI], 0.14-0.46; p < 0.001), 56 % lower in the antibiotic than control group (OR, 0.44; 95 % CI, 0.19-0.99; p = 0.048), and 52 % lower in the mupirocin than antibiotic group (OR, 0.48; 95 % CI, 0.21-1.10; p = 0.084). The difference in the probability of S. aureus peritonitis in patients undergoing peritoneal dialysis was not statistically significant among the three groups.

CONCLUSIONS

Mupirocin and topical antibiotics were effective for reduction of S. aureus catheter site infection in patients undergoing peritoneal dialysis when compared with no treatment or placebo. However, evidence was insufficient to identify the optimal agent, route, or duration of antibiotics to treat peritonitis.

Vancomycin-Resistant Enterococcus (VRE) Transmission and Risk Factors in Contacts of VRE Carriers

During a 2-year period, the vancomycin-resistant enterococcus (VRE) acquisition rate was 10.9% (40/368) in patients who had shared a room with a newly detected VRE carrier. Exposure to vancomycin and to anti-anaerobic antibiotics were identified as independent risk factors for VRE acquisition. Sensitivity of the first rectal VRE screening was less than 50%.

Infect Control Hosp Epidemiol 2014;35(7):876–879

[Survey of methicillin-resistant Staphylococcus aureus control measures in hospitals participating in the VINCat program]

INTRODUCTION

VINCat is a nosocomial infection surveillance program in hospitals in Catalonia. The aim of the study was to determine the surveillance and control measures of methicillin-resistant Staphylococcus aureus (MRSA) in these centres.

METHODS

An e-mail survey was carried out from January to March 2013 with questions related to the characteristics of the hospitals and their control measures for MRSA.

RESULTS

A response was received from 53 hospitals (>500 beds: 7; 200-500 beds: 14;<200 beds: 32; had ICU: 29). Computer alert of readmissions was available in 63%. There was active surveillance of patients admitted from another hospital (46.2%) or a long-term-care centre (55.8%), both being significantly more common measures in hospitals with a rate of MRSA≤22% (global median). Compliance with hand hygiene was observed in 77.4% of the centres, and was greater than 50% in 69.7% of them. All hospitals had contact precautions, although 62.3% did not have exclusive frequently used clinical material in bedrooms. The room cleaning was performed more frequently in 54.7% of hospitals, and 67.9% of them had programs for the appropriate use of antibiotics.

CONCLUSIONS

This study provides information on the implementation of measures to prevent MRSA in hospitals participating in the VINCat program. Most of the centres have an MRSA protocol, however compliance with it should be improved, especially in areas such as active detection on admission in patients at risk, hand hygiene adherence, cleaning frequency and optimising the use of antibiotics.

Impact of a Mandatory Infection Control Education Program on Nosocomial Acquisition of Methicillin-ResistantStaphylococcus aureus

Objective.

To assess the impact of an institution-wide infection control education program on the rate of transmission of methicillin-resistantStaphylococcus aureus(MRSA).

Design.

Before-and-after study.

Setting.

A 472-bed, urban, university-affiliated hospital.

Intervention.

During the period March-May 2004, all hospital staff completed a mandatory infection control education program, including the receipt of hospital-specific MRSA data and case-based practice with additional precautions.

Outcome Measure.

The rate of nosocomial MRSA acquisition was calculated as the number of cases of nosocomial MRSA acquisition per 100 days that a person with MRSA colonization or infection detected at admission is present in the hospital (“admission MRSA” exposure-days) for 3 time periods: June 2002-February 2003 (before the Toronto outbreak of severe acute respiratory syndrome [SARS]), June 2003-February 2004 (after the outbreak of SARS), and June 2004-February 2005 (after education). A case of nosocomial acquisition of MRSA colonization or infection represented a patient first identified as colonized or infected more than 72 hours after admission or at admission after a previous hospitalization.

Results.

The rate of nosocomial acquisition of MRSA colonization or infection was 8.8 cases per 100 admission MRSA exposure-days for the period before SARS, 3.8 cases per 100 admission MRSA exposure-days for the period after SARS (P< .001 for before SARS vs after SARS), and 1.9 cases per 100 admission MRSA exposure-days for the period after education (P= .02 for after education vs before education). The volume of alcohol-based handrub purchased was apparently stable, with 4,010 L during fiscal year 2003-2004 (April 2003-March 2004) compared with 3,780 L during fiscal year 2004—2005. The observed rate of compliance with hand washing did not change significantly (40.9% during education vs 44.2% after education;P= .23). The total number of patients screened for MRSA colonization was not different in the 3 periods.

Conclusions.

The rate of nosocomial acquisition of MRSA colonization or infection decreased after SARS and was further reduced in association with a hospital-wide education program.

Screening and treatment for Staphylococcus aureus in patients undergoing hemodialysis: a systematic review and meta-analysis

BACKGROUND

This study was performed to evaluate the effectiveness of surveillance for screening and treatment of patients with chronic kidney disease undergoing hemodialysis and colonized by Staphylococcus aureus.

METHODS

A systematic review and meta-analysis were performed. The literature search involved the following databases: the Cochrane Controlled Trials Register, Embase, LILACS, CINAHL, SciELO, and PubMed/Medline. The descriptors were "Staphylococcus aureus", "MRSA", "MSSA", "treatment", "decolonization", "nasal carrier", "colonization", "chronic kidney disease", "dialysis", and "haemodialysis" or "hemodialysis". Five randomized controlled trials that exhibited agreement among reviewers as shown by a kappa value of >0.80 were included in the study; methodological quality was evaluated using the STROBE statement. Patients who received various treatments (various treatments group) or topical mupirocin (mupirocin group) were compared with those who received either no treatment or placebo (control group). The outcomes were skin infection at the central venous catheter insertion site and bacteremia.

RESULTS

In total, 2374 patients were included in the analysis, 626 (26.4%) of whom were nasal carriers of S. aureus. The probability of S. aureus infection at the catheter site for hemodialysis was 87% lower in the mupirocin group than in the control group (odds ratio [OR], 0.13; 95% confidence interval [CI], 0.05-0.34; p<0.001). The risk of bacteremia was 82% lower in the mupirocin group than in the control group (OR, 0.18; 95% CI, 0.08-0.42; p<0.001). No statistically significant difference in bacteremia was observed between the various treatments group (excluding mupirocin) and the control group (OR, 0.77; 95% CI, 0.51-1.15; p=0.20).

CONCLUSIONS

Twenty-six percent of patients undergoing hemodialysis were nasal carriers of S. aureus. Of all treatments evaluated, topical mupirocin was the most effective therapy for the reduction of S. aureus catheter site infection and bacteremia in patients undergoing chronic hemodialysis.

Healthcare workers as vectors of infectious diseases

Nosocomial infections cause considerable morbidity and mortality. Healthcare workers (HCWs) may serve as vectors of many infectious diseases, many of which are not often primarily considered as healthcare-associated. The probability of pathogen transmission to patients depends on several factors, such as the characteristics of a pathogen, HCW and patient. Pathogens with high transmission potential from HCWs to patients include norovirus, respiratory infections, measles and influenza. In contrast, human immunodeficiency virus (HIV) and viral hepatitis are unlikely to be transferred. The prevention of HCW-associated transmission of pathogens include systematic vaccinations towards preventable diseases, continuous education, hand hygiene surveillance, active feedback and adequate staff resources.

Epidemiology of Staphylococcus aureus harboring the mecA or Panton-Valentine leukocidin genes in hospitals in Java and Bali, Indonesia

Data of Staphylococcus aureus carriage in Indonesian hospitals are scarce. Therefore, the epidemiology of S. aureus among surgery patients in three academic hospitals in Indonesia was studied. In total, 366 of 1,502 (24.4%) patients carried S. aureus. The methicillin-resistant S. aureus (MRSA) carriage rate was 4.3%, whereas 1.5% of the patients carried Panton-Valentine leukocidin (PVL)-positive methicillin-sensitive S. aureus (MSSA). Semarang and Malang city (odds ratio [OR] 9.4 and OR 9.0), being male (OR 2.4), hospitalization for more than 5 days (OR 11.708), and antibiotic therapy during hospitalization (OR 2.6) were independent determinants for MRSA carriage, whereas prior hospitalization (OR 2.5) was the only one risk factor for PVL-positive MSSA carriage. Typing of MRSA strains by Raman spectroscopy showed three large clusters assigned type 21, 24, and 38, all corresponding to ST239-MRSA-SCCmec type III. In conclusion, MRSA and PVL-positive MSSA are present among patients in surgical wards in Indonesian academic hospitals.

A hierarchical spatial modelling approach to investigate MRSA transmission in a tertiary hospital

Background

Most hospitals have a hierarchical design with beds positioned within cubicles and cubicles positioned within wards. Transmission of MRSA may be facilitated by patient proximity and thus the spatial arrangements of beds, cubicles and wards could be important in understanding MRSA transmission risk. Identifying high-risk areas of transmission may be useful in the design of more effective, targeted MRSA interventions.

Methods

Retrospective data on numbers of multi-resistant and non-multiresistant MRSA acquisitions were collected for 52 weeks in 2007 in a tertiary hospital in Brisbane, Australia. A hierarchical Bayesian spatio-temporal modelling approach was used to investigate spatial correlation in the hierarchically arranged datasets. The spatial component of the model decomposes cubicle-level variation into a spatially structured component and a spatially unstructured component, thereby encapsulating the influence of unmeasured predictor variables that themselves are spatially clustered and/or random. A fixed effect for the presence of another patient with the same type of MRSA in the cubicles two weeks prior was included.

Results

The best-fitting model for non-multiresistant MRSA had an unstructured random effect but no spatially structured random effect. The best-fitting model for multiresistant MRSA incorporated both spatially structured and unstructured random effects. While between-cubicle variability in risk of MRSA acquisition within the hospital was significant, there was only weak evidence to suggest that MRSA is spatially clustered. Presence of another patient with the same type of MRSA in the cubicles two weeks prior was a significant predictor of both types of MRSA in all models.

Conclusions

We found weak evidence of clustering of MRSA acquisition within the hospital. The presence of an infected patient in the same cubicle two weeks prior may support the importance of environmental contamination as a source of MRSA transmission.

Discontinuation of contact precautions for methicillin-resistant staphylococcus aureus: a randomized controlled trial comparing passive and active screening with culture and polymerase chain reaction

BACKGROUND

There have been no randomized controlled trials comparing active and passive screening for documenting clearance of colonization with methicillin-resistant Staphylococcus aureus (MRSA). We compared the efficacy of active and passive screening using both culture and commercial polymerase chain reaction (PCR) for documentation of MRSA clearance and discontinuation of MRSA contact precautions (CPs).

METHODS

Inpatients with a history of MRSA infection or colonization enrolled between December 2010 and September 2011 were randomized to either passive (nonintervention arm; n = 202; observation with local standard of care) or active screening (intervention arm; n = 405; study staff screened using culture and commercial PCR). The primary outcome was discontinuation of CPs by trial arm based on 3 negative cultures. In the intervention arm, sensitivity, specificity, and positive and negative predictive values of the first PCR were compared to cultures.

RESULTS

CPs were discontinued significantly more often (rate ratio [RR], 4.1; 95% confidence interval [CI], 2.3%-7.1%) in the intervention arm, including in an intent-to-screen analysis (RR, 2.6; 95% CI, 1.5%-4.7%). The first PCR, compared to 3 cultures, detected MRSA with a sensitivity of 93.9% (95% CI, 85.4%-97.6%), a specificity of 92.0% (95% CI, 85.9%-95.6%), a positive predictive value of 86.1% (95% CI, 75.9%-93.1%), and a negative predictive value of 96.6% (95% CI, 91.6%-99.1%).

CONCLUSIONS

Compared to passive screening using culture methods, active screening resulted in discontinuation of MRSA CPs at a significantly higher frequency. Active screening with a single PCR would significantly increase the completion of the screening process. Clinical Trials Registration. NCT01234831.

Cohorting based on nasal methicillin-resistant Staphylococcus aureus status: an opportunity to share more than a room

BACKGROUND

Hospital roommates are cohorted with similarly colonized patients to decrease methicillin-resistant Staphylococcus aureus (MRSA) transmission risk. However, little is known about differences in S aureus nasal and extranasal carriage between hospital roommates who are in MRSA or non-MRSA designated rooms.

METHODS

Patients sharing hospital rooms were cultured for S aureus in the nose, throat, and other body sites. Differences in S aureus methicillin and mupirocin susceptibility and USA300 type were evaluated.

RESULTS

Eighty-two patients comprising 48 roommate pairs were studied. Among 6 roommate pairs in MRSA rooms, 3 (50%) had differences in carriage based on having methicillin-susceptible S aureus at an extranasal body site. In non-MRSA rooms, 19 (45%) roommate pairs had differences in S aureus carriage. Extranasal colonization was significantly associated with discordance between roommates, P < .001. Antibiotic exposure, ward type, and the duration of room sharing were not associated with discordance.

CONCLUSION

Patients have almost a 50% chance of having differences in S aureus colonization compared with their hospital roommate, even in MRSA-designated rooms. Cohorting by MRSA status at the time of admission may not be as effective a control strategy as horizontal measures that do not rely on known colonization with S aureus or other pathogens.

A multilevel model of methicillin-resistant Staphylococcus aureus acquisition within the hierarchy of an Australian tertiary hospital

Hospitals without universal single room accommodations typically contain multibed cubicles within wards. In this study, we examined whether the variation in a patient's risk for acquiring methicillin-resistant Staphylococcus aureus (MRSA) in a major tertiary hospital was greatest at the bed, cubicle, or ward level, and quantified the risk of MRSA acquisition associated with exposure to MRSA-colonized/infected patients within the same bed, cubicle, and ward at differently distributed lag times. Nested tri-level hierarchical logistic regression models with random effects were used for non-multiresistant MRSA (nmMRSA) and multiresistant MRSA (mMRSA). The models were internally validated. Receiver operating characteristic curves were used to compare the models' predictive capability The odds of new nmMRSA acquisition were 6.06-fold (95% credible intervals [CrI], 3.93- to 9.34-fold) greater in bed-weeks when a nmMRSA-colonized/infected patient was in the same cubicle 2 weeks earlier. The odds of mMRSA acquisition were 5.12-fold (95% CrI, 4.02- to 6.51-fold) greater in bed-weeks when a colonized/infected patient was in the same ward 2 weeks earlier. The between-cluster variance was highest at the ward level. Patients were at greater risk if there was a colonized/infected patient in the same cubicle or ward 2 weeks earlier. Our findings indicate that focusing on the relevant cubicles and wards during this high-risk period can help target infection control resources more efficiently.

Too close for comfort: screening strategy to detect methicillin-resistant Staphylococcus aureus conversion in exposed roommates

All 899 roommates exposed to methicillin-resistant Staphylococcus aureus (MRSA) index cases were studied over 57 months. MRSA detection is better at approximately 3 days (50%-55%) or 7 days (56%) after contact has been broken than day 0 (30%). Polymerase chain reaction testing at day 3 performs similarly to culture at day 7. Nasal/rectal screening provides superior detection than nasal alone. Those exposed >48 hours are at significantly greater risk of colonization.

Nursing home characteristics associated with methicillin-resistant Staphylococcus aureus (MRSA) Burden and Transmission

BACKGROUND

MRSA prevalence in nursing homes often exceeds that in hospitals, but reasons for this are not well understood. We sought to measure MRSA burden in a large number of nursing homes and identify facility characteristics associated with high MRSA burden.

METHODS

We performed nasal swabs of residents from 26 nursing homes to measure MRSA importation and point prevalence, and estimate transmission. Using nursing home administrative data, we identified facility characteristics associated with MRSA point prevalence and estimated transmission risk in multivariate models.

RESULTS

We obtained 1,649 admission and 2,111 point prevalence swabs. Mean MRSA point prevalence was 24%, significantly higher than mean MRSA admission prevalence, 16%, (paired t-test, p<0.001), with a mean estimated MRSA transmission risk of 16%.In multivariate models, higher MRSA point prevalence was associated with higher admission prevalence (p=0.005) and higher proportions of residents with indwelling devices (p=0.01). Higher estimated MRSA transmission risk was associated with higher proportions of residents with diabetes (p=0.01) and lower levels of social engagement (p=0.03).

CONCLUSIONS

MRSA importation was a strong predictor of MRSA prevalence, but MRSA burden and transmission were also associated with nursing homes caring for more residents with chronic illnesses or indwelling devices. Frequent social interaction among residents appeared to be protective of MRSA transmission, suggesting that residents healthy enough to engage in group activities do not incur substantial risks of MRSA from social contact. Identifying characteristics of nursing homes at risk for high MRSA burden and transmission may allow facilities to tailor infection control policies and interventions to mitigate MRSA spread.

Demographic screening for MRSA may compromise the effectiveness of ring fencing on a joint replacement unit

Ring fencing of joint replacement (JR) units has been reported to reduce infections and is recommended by health authorities in Australia and the UK. It has not been determined whether a demographic risk assessment is adequate to prevent the admission of patients colonized with meticillin-resistant Staphylococcus aureus (MRSA) to ring-fenced units. As such, 250 admissions to the JR unit of a suburban Sydney hospital were screened, and MRSA colonization was identified in 2.8% of patients complying with the demographic risk assessment. Demographic risk assessment is not an adequate substitute for physical MRSA screening, and undermines the effectiveness of ring-fencing procedures.

Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in residents of Veterans Affairs long-term care facilities: role of antimicrobial exposure and MRSA acquisition

OBJECTIVE

To identify risk factors associated with methicillin-resistant Staphylococcus aureus (MRSA) acquisition in long-term care facility (LTCF) residents.

DESIGN

Multicenter, prospective cohort followed over 6 months.

SETTING

Three Veterans Affairs (VA) LTCFs.

PARTICIPANTS

All current and new residents except those with short stay (<2 weeks).

METHODS

MRSA carriage was assessed by serial nares cultures and classified into 3 groups: persistent (all cultures positive), intermittent (at least 1 but not all cultures positive), and noncarrier (no cultures positive). MRSA acquisition was defined by an initial negative culture followed by more than 2 positive cultures with no subsequent negative cultures. Epidemiologic data were collected to identify risk factors, and MRSA isolates were typed by pulsed-field gel electrophoresis (PFGE).

RESULTS

Among 412 residents at 3 LTCFs, overall MRSA prevalence was 58%, with similar distributions of carriage at all 3 facilities: 20% persistent, 39% intermittent, 41% noncarriers. Of 254 residents with an initial negative swab, 25 (10%) acquired MRSA over the 6 months; rates were similar at all 3 LTCFs, with no clusters evident. Multivariable analysis demonstrated that receipt of systemic antimicrobials during the study was the only significant risk factor for MRSA acquisition (odds ratio, 7.8 [95% confidence interval, 2.1-28.6]; P = .002). MRSA strains from acquisitions were related by PFGE to those from a roommate in 9/25 (36%) cases; 6 of these 9 roommate sources were persistent carriers.

CONCLUSIONS

MRSA colonization prevalence was high at 3 separate VA LTCFs. MRSA acquisition was strongly associated with antimicrobial exposure. Roommate sources were often persistent carriers, but transmission from roommates accounted for only approximately one-third of MRSA acquisitions.

Filmcards Used in Radiation Therapy: Are They a Potential Source of Cross-infection?

INTRODUCTION

Industrial radiographic film (exposed to light and then cut into a filmcard) is a tool used by radiation therapists (RTs) in the setup of patients before delivering external beam radiation therapy. At the Tom Baker Cancer Center (TBCC), filmcards are reused throughout the day on multiple patients and multiple body sites; thus the risk of cross-contamination exists. The primary objective of this study was to assess the risk of cross-contamination by determining the potential for bacteria to survive on filmcards, in an effort to reduce the risk of cross-infection.

METHODS AND MATERIALS

This control study evaluated the potential of the following to survive on filmcards: coliforms, Pseudomonas, Staphylococcus spp. (specifically S. aureus and methicillin-resistant S. aureus [MRSA]), Enterococcus, and hemolytic streptococcus species. Thirty filmcards used by RTs throughout the day were collected and voluntarily placed in individual collection bags. Thirty control cards (unused filmcards) were also collected. Collection bags were stored at 4°C until cultured. A reference strain of MRSA (38591) was used in the MRSA survival assay, along with methicillin-sensitive S. aureus (MSSA) isolate (pure form). The MRSA survival experiment required eight larger, unused filmcards (four designated as negative controls and four positive control cards) to be cut into 28.5 × 6.5 cm. Microbiological plates were used to identify and select for bacteria. The various selective and differential plates contain growth factors, antimicrobials, and color indicators that can selectively allow some groups of bacteria to grow on the plate while inhibiting other types of bacteria.

RESULTS

This study provides evidence to support that filmcards are a source of cross-contamination. 58% (17/29) of the used filmcards tested positive for pathogenic bacteria, compared to only 20% (6/30) of the control cards (P = 0.003). Staphylococcus aureus bacteria were present on 11/29 (38%) of the used filmcards, compared to 2/30 (6.7%) on the control filmcards (P = 0.005). Other colonies found on the used filmcards included strep bacteria (P = 0.24), entero bacteria (P = 0.24), and skin flora (P = 0.36); and although reported as statistically insignificant, these bacteria were viable and thus hold a level of clinical significance. In addition, this experiment provides evidence that certain bacteria (including MRSA found to survive on filmcards for at least 21 days) were viable on filmcards, but an incidental finding reports that fungi is also able to survive on filmcards.

CONCLUSION

Filmcards used by RTs can harbor a number of pathogenic bacteria, including MRSA, and are therefore a source of cross-contamination. We recommend that the TBCC external beam radiation treatment program-and any other facilities providing external beam radiation therapy-adopt infection control policies that support discarding filmcards after each use (one-time per patient use) or adopt policies that endorse the elimination of filmcards entirely.

Colonization pressure adjusted by degree of environmental contamination: a better indicator for predicting methicillin-resistant Staphylococcus aureus acquisition

BACKGROUND

Colonization pressure has been confirmed as an important risk factor for methicillin-resistant Staphylococcus aureus (MRSA) acquisition among inpatients, but their precise relationship has not been well investigated. Because MRSA carriers can disperse MRSA into their immediate environment with different abilities, the relationship among colonization pressure, the degree of MRSA contamination in environment surrounding MRSA carriers, and MRSA transmission should be explored to facilitate efficient implementation of infection control measures.

METHODS

Active MRSA screening and environmental sampling were performed in a 23-bed emergency ward (EW) and a 7-bed respiratory intensive care unit (RICU) between March 2009 and February 2010. Weekly colonization pressure (WCP) was modified to WCPe (WCP adjusted by degree of environmental contamination). Receiver operating characteristic curve and correlation analyses were used to analyze the accuracy of WCPe in predicting MRSA acquisition and their correlation, respectively.

RESULTS

We found that 34.1% (858/2,520) of the immediate environmental sites of MRSA-positive patients were contaminated with MRSA. The areas under the receiver operating characteristic curve of WCPe reached as high as 0.784 (95% confidence interval, 0.659-0.909; P < .01) for the EW and 0.866 (95% confidence interval, 0.766-0.967; P < .01) for the RICU. Spearman's correlation coefficient (r) indicated a positive and significant correlation between WCPe and MRSA acquisition rate in the subsequent weeks for both the EW (r = 0.45; P = .001) and RICU (r = 0.51; P < .001).

CONCLUSION

Active MRSA screening combined with targeted environmental contamination monitoring could be a more efficient measure for determining the magnitude of the MRSA reservoir in wards occupied by MRSA carriers. WCPe showed moderate prediction accuracy for both the EW and the RICU, and a threshold WCPe value may be used as a predictor to enhance infection control measures, especially for medical facilities without a sufficient number of single rooms.

Modelling the transmission dynamics of meticillin-resistant Staphylococcus aureus in Beijing Tongren hospital

Semi-professional volunteers work in many tertiary care hospitals in China as healthcare assistants. Proper infection control measures are needed to reduce nosocomial transmission involving volunteers. A compartmental model was constructed to describe the transmission characteristics of meticillin-resistant Staphylococcus aureus (MRSA) in the emergency ward (EW) and respiratory intensive care unit (RICU) for volunteers in Beijing Tongren Hospital, Beijing, China. The model consists of components describing uncolonized and colonized patients, uncontaminated and contaminated healthcare workers (HCWs), and uncontaminated and contaminated volunteers. The basic reproduction number (R(0)) was calculated, and the dependence of R(0) on various model parameters was analysed. Moreover, simulations of the model were performed for comparision with the reported data on the numbers of colonized patients in the EW and RICU from 3 March 2009 to 28 February 2010, respectively. Sensitivity analysis of R(0) showed that increasing handwashing compliance among HCWs and volunteers would reduce the risk of transmission dramatically. As volunteers care for patients on a one-to-one basis, this study showed that the number of MRSA-positive patients would increase if volunteers were replaced by HCWs. Therefore, in addition to improving hand hygiene among HCWs, the employment of properly trained volunteers is an attractive alternative to decrease MRSA and other multi-drug resistant bacteria infections in the hospital setting.

Use of antibacterial prophylaxis for patients with neutropenia. Australian Consensus Guidelines 2011 Steering Committee

The use of oral prophylactic antibiotics in patients with neutropenia is controversial and not recommended by this group because of a lack of evidence showing a reduction in mortality and concerns that such practice promotes antimicrobial resistance. Recent evidence has demonstrated non-significant but consistent, improvement in all-cause mortality when fluoroquinolones (FQs) are used as primary prophylaxis. However, the consensus was that this evidence was not strong enough to recommend prophylaxis. The evidence base for FQ prophylaxis is presented alongside current consensus opinion to guide the appropriate and judicious use of these agents. Due consideration is given to patient risk, as it pertains to specific patient populations, as well as the net effect on selective pressure from antibiotics if FQ prophylaxis is routinely used in a target population. The potential costs and consequences of emerging FQ resistance, particularly among Escherichia coli, Clostridium difficile and Gram-positive organisms, are considered. As FQ prophylaxis has been advocated in some chemotherapy protocols, specific regard is given to whether FQ prophylaxis should be used to support these regimens. The group also provides recommendations for monitoring and surveillance of emerging resistance in those centres that have adopted FQ prophylaxis.

Patient-associated risk factors for acquisition of methicillin-resistant Staphylococcus aureus in a tertiary care hospital

BACKGROUND

Determining risk factors for acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals is important for defining infection-control measures that may lead to fewer hospital-acquired infections.

OBJECTIVE

To determine patient-associated risk factors for acquisition of MRSA in a tertiary care hospital with the goal of identifying modifiable risk factors.

METHODS

A retrospective matched case-control study was performed. Case patients who acquired MRSA during hospitalization and 2 matched control patients were selected among inpatients admitted to target units during the period from 2001 through 2008. The odds of exposure to potential risk factors were compared between case patients and control patients, using matched univariate conditional logistic regression. A single multivariate conditional logistic regression model identifying independent patient-specific risk factors was generated.

RESULTS

A total of 451 case patients and 866 control patients were analyzed. Factors positively associated with MRSA acquisition were as follows: target unit stay before index culture; primary diagnosis of respiratory disease, digestive tract disease, injury or trauma, or other diagnosis compared with cardiocirculatory disease; peripheral vascular disease; mechanical ventilation with pneumonia; ventricular shunting or ventriculostomy; and ciprofloxacin use. Factors associated with decreased risk were receipt of a solid-organ transplant and use of penicillins, cephalosporins, rifamycins, daptomycin or linezolid, and proton pump inhibitors.

CONCLUSION

Among the factors associated with increased risk, few are modifiable. Patients with at-risk conditions could be targeted for intensive surveillance to detect acquisition sooner. The association of MRSA acquisition with target unit exposure argues for rigorous application of hand hygiene, appropriate barriers, environmental control, and strict aseptic technique for all procedures performed on such patients. Our findings support focusing efforts to prevent MRSA transmission and restriction of ciprofloxacin use.

Occurrence of skin and environmental contamination with methicillin-resistant Staphylococcus aureus before results of polymerase chain reaction at hospital admission become available

BACKGROUND

Active surveillance to detect patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) is increasingly practiced in healthcare settings. However, inpatients may already become sources of transmission before appropriate precautions are implemented.

OBJECTIVE

To examine the frequency of MRSA contamination of commonly touched skin and environmental surfaces before patient carriage status became known.

METHODS

We conducted a 6-week prospective study of patients who were identified by use of polymerase chain reaction (PCR) at hospital admission as having nasal MRSA colonization. Skin and environmental contamination was assessed within hours of completion of PCR screening.

RESULTS

There were 116 patients identified by PCR screening as having nasal MRSA colonization during the period from mid-April to May 2008, of whom 83 (72%) were enrolled in our study. Overall, MRSA was detected on the skin of 38 (51%) of 74 patients and in the environment of 37 (45%) of 83 patients. Of 83 environmental culture samples, 63 (76%) were obtained within 7 hours after PCR results became available, and 73 (88%) were obtained before wards were notified of PCR results. Of the 83 MRSA-colonized patients, 15 (18%) had contaminated their environment 25 hours after admission, and 29 (35%) had contaminated their environment 33 hours after admission. Thirty-two (39%) of the 83 patients had roommates, 13 (41%) of whom contaminated their environment. The median interval from admission to PCR result was 20 hours, and the median interval from PCR result to notification was 23 hours. An increased quantity of MRSA cultured from a nasal sample was significantly associated with contamination.

CONCLUSIONS

Before any contact precautions can be implemented, newly identified MRSA carriers frequently have contaminated their environment with MRSA and have contamination of commonly examined skin sites. In hospitals that perform active surveillance, strategies are needed to minimize delays in screening or to preemptively identify patients at high risk for disseminating MRSA.

Methicillin-resistant Staphylococcus aureus in Canada: a historical perspective and lessons learned

The history of methicillin-resistant Staphylococcus aureus (MRSA) in Canada has many similarities to MRSA evolution worldwide, but especially to that in the United States and United Kingdom. Reports of MRSA occurred as early as 1964, and community isolates were cited in the 1970s. Nosocomial outbreaks were becoming common by 1978 and flourished gradually thereafter. Endemic institutional MRSA became predominant in the 1990s, threatening large teaching hospitals in particular. In the last decade, both hospital-acquired and community-acquired MRSA have created major medical problems in Canada. More recently, an epidemic of Canadian community-acquired MRSA-10, has led to heightened public health concerns. Canadian contributions to MRSA science are numerous, with organized surveillance continuing to mature across the nation. A typing system for epidemic clones is now available and is being judiciously applied. Estimated costs for MRSA surveillance, treatment, and control are extraordinary, paralleling the dramatic rise in the number of MRSA isolations. Whereas surveillance continues to form an essential aspect of MRSA management, control, eradication, and overall diminution, MRSA reservoirs deserve much greater attention. Such efforts, however, must be as widely publicized in the community and in patient homes as they are in medical institutions responsible for both acute and long-term care.

Exposure to hospital roommates as a risk factor for health care-associated infection

BACKGROUND

Numerous patient- and hospital-level characteristics have been established as risk factors for the transmission of health care-associated infections (HAIs). Few studies have quantitatively assessed the impact of exposure to hospital roommates on the acquisition of infections. This study evaluated the association between roommate exposures and the risk of HAIs.

METHODS

A retrospective cohort of adult patients admitted to a Canadian teaching hospital between June 30, 2001, and December 31, 2005, was studied. Exposures were characterized as total daily roommate exposures and daily unique roommate exposures. Outcomes examined were methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile.

RESULTS

The number of roommate exposures per day was significantly associated with MRSA and VRE infection or colonization (MRSA: hazard ratio [HR] = 1.10, 95% confidence interval [CI] = 1.05 to 1.15; VRE: HR = 1.11, 95% CI = 1.02 to 1.21), and with C difficile infection (HR = 1.11, 95% CI = 1.03 to 1.19). A significant association also was found for number of unique roommate exposures per day and VRE (HR = 1.15, 95% CI = 1.02 to 1.28).

CONCLUSIONS

The significant associations found between daily roommate exposures and the infection outcomes suggest a possible role for limiting patient-to-patient contact in an infection prevention and control program in this facility. These findings have implications for the deployment and design of acute care hospitals.

Can 'search and destroy' reduce nosocomial methicillin-resistant Staphylococcus aureus in an Irish hospital?

In Ireland, the Department of Health and Children recommends admission screening of patients at increased risk of methicillin-resistant Staphylococcus aureus (MRSA), isolation of these patients until proven negative, and eradication of any MRSA identified. These actions form the basis of a programme called 'search and destroy' that has successfully reduced MRSA in Scandinavia. There is, however, very little information published on the use of search and destroy in Ireland. This study was carried out using a quantitative, quasi-experimental design in the form of an interventional cohort study. The effect of reducing the turnaround time for MRSA results (2007) and the introduction of pre-emptive isolation (2008) was examined in a hospital with an established admission screening programme for MRSA. Rates of MRSA infection and colonisation were monitored post-intervention and compared to baseline rates prior to the intervention (2005-2006). Rates of hospital-acquired (nosocomial) MRSA infections and colonisation fell in both 2007 and 2008. However, due to the quasi-experimental design of the study and the low endemic level of MRSA in the hospital, a causal link could not be established.

Transmission of methicillin-resistant Staphylococcus aureus to household contacts

The frequency of and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) transmission from a MRSA index person to household contacts were assessed in this prospective study. Between January 2005 and December 2007, 62 newly diagnosed MRSA index persons (46 patients and 16 health care workers) and their 160 household contacts were included in the study analysis. Transmission of MRSA from an index person to household contacts occurred in nearly half of the cases (47%; n = 29). These 29 index persons together had 84 household contacts, of which two-thirds (67%; n = 56) became MRSA positive. Prolonged exposure time to MRSA at home was a significant risk factor for MRSA transmission to household contacts. In addition, MRSA colonization at least in the throat, younger age, and eczema in index persons were significantly associated with MRSA transmission; the presence of wounds was negatively associated with MRSA transmission. Furthermore, an increased number of household contacts and being the partner of a MRSA index person were household-related risk factors for MRSA acquisition from the index person. No predominant pulsed-field gel electrophoresis (PFGE) type was observed to be transmitted more frequently than other PFGE types. To date, screening household contacts and providing MRSA eradication therapy to those found positive simultaneously with the index person is not included in the "search-and-destroy" policy. We suggest including both in MRSA prevention guidelines, as this may reduce further spread of MRSA.

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

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