Methicillin-resistant Staphylococcus aureus transmission: the possible importance of unrecognized health care worker carriage

Factors associated with patient-to-healthcare personnel (HCP) and HCP-to-subsequent patient transmission of methicillin-resistant Staphylococcus aureus

BACKGROUND

Transient acquisition of methicillin-resistant Staphylococcus aureus (MRSA) on healthcare personnel (HCP) gloves and gowns following patient care has been examined. However, the potential for transmission to the subsequent patient has not been studied. We explored the frequency of MRSA transmission from patient to HCP, and then in separate encounters from contaminated HCP gloves and gowns to a subsequent simulated patient as well as the factors associated with these 2 transmission pathways.

METHODS

We conducted a prospective cohort study with 2 parts. In objective 1, we studied MRSA transmission from random MRSA-positive patients to HCP gloves and gowns after specific routine patient care activities. In objective 2, we simulated subsequent transmission from random HCP gloves and gowns without hand hygiene to the next patient using a manikin proxy.

RESULTS

For the first objective, among 98 MRSA-positive patients with 333 randomly selected individual patient-HCP interactions, HCP gloves or gowns were contaminated in 54 interactions (16.2%). In a multivariable analysis, performing endotracheal tube care had the greatest odds of glove or gown contamination (OR, 4.06; 95% CI, 1.3-12.6 relative to physical examination). For the second objective, after 147 simulated HCP-patient interactions, the subsequent transmission of MRSA to the manikin proxy occurred 15 times (10.2%).

CONCLUSION

After caring for a patient with MRSA, contamination of HCP gloves and gown and transmission to subsequent patients following HCP-patient interactions occurs frequently if contact precautions are not used. Proper infection control practices, including the use of gloves and gown, can prevent this potential subsequent transmission.

Role of Daptomycin in Cutaneous Wound Healing: A Narrative Review

Daptomycin is active against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and the on-label indications for its use include complicated skin and skin structure infections (cSSSI). We performed a narrative review of the literature with the aim to evaluate the role of daptomycin in the skin wound healing process, proposing our point of view on the possible association with other molecules that could improve the skin healing process. Daptomycin may improve wound healing in MRSA-infected burns, surgical wounds, and diabetic feet, but further studies in humans with histological examination are needed. In the future, the combination of daptomycin with other molecules with synergistic action, such as vitamin E and derivates, IB-367, RNA III-inhibiting peptide (RIP), and palladium nanoflowers, may help to improve wound healing and overcome forms of antibiotic resistance.

Comparing methods to estimate incremental inpatient costs and length of stay due to methicillin-resistant Staphylococcus aureus in Alberta, Canada

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is an opportunistic bacterial organism resistant to first line antibiotics. Acquisition of MRSA is often classified as either healthcare-associated or community-acquired. It has been shown that both healthcare-associated and community-acquired infections contribute to the spread of MRSA within healthcare facilities. The objective of this study was to estimate the incremental inpatient cost and length of stay for individuals colonized or infected with MRSA. Common analytical methods were compared to ensure the quality of the estimate generated. This study was performed at Alberta Ministry of Health (Edmonton, Alberta), with access to clinical MRSA data collected at two Edmonton hospitals, and ministerial administrative data holdings.

Methods

A retrospective cohort study of patients with MRSA was identified using a provincial infection prevention and control database. A coarsened exact matching algorithm, and two regression models (semilogarithmic ordinary least squares model and log linked generalized linear model) were evaluated. A MRSA-free cohort from the same facilities and care units was identified for the matched method; all records were used for the regression models. Records span from January 1, 2011 to December 31, 2015, for individuals 18 or older at discharge.

Results

Of the models evaluated, the generalized linear model was found to perform the best. Based on this model, the incremental inpatient costs associated with hospital-acquired cases were the most costly at $31,686 (14,169 – 60,158) and $47,016 (23,125 – 86,332) for colonization and infection, respectively. Community-acquired MRSA cases also represent a significant burden, with incremental inpatient costs of $7397 (2924 – 13,180) and $14,847 (8445 – 23,207) for colonization and infection, respectively. All costs are adjusted to 2016 Canadian dollars. Incremental length of stay followed a similar pattern, where hospital-acquired infections had the longest incremental stays of 35.2 (16.3–69.5) days and community-acquired colonization had the shortest incremental stays of 3.0 (0.6–6.3) days.

Conclusions

MRSA, and in particular, hospital-acquired MRSA, places a significant but preventable cost burden on the Alberta healthcare system. Estimates of cost and length of stay varied by the method of analysis and source of infection, highlighting the importance of selecting the most appropriate method.

Mupirocin resistance in Staphylococcus aureus: A systematic review and meta-analysis

OBJECTIVES

Staphylococcus aureus is one of the most common pathogens causing nosocomial and community-acquired infections associated with high morbidity and mortality. Mupirocin has been increasingly used for treatment of methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) infections. The aim of this study was to determine the prevalence of mupirocin-resistant S. aureus (MuRSA), mupirocin-resistant MRSA (MuRMRSA), high-level MuRSA (HLMuRSA) and high-level MuRMRSA (HLMuRMRSA) worldwide.

METHODS

Online databases including Medline, Embase and Web of Science were searched (2000-2018) to identify studies addressing the prevalence of MuRSA, MuRMRSA, HLMuRSA and HLMuRMRSA. STATA v. software was used to interpret the data.

RESULTS

Of the 2243 records identified from the databases, 30 and 63 studies fulfilled the eligibility criteria for MuRSA and MuRMRSA, respectively. Finally, 27 and 60 studies were included separately for HLMuRSA and HLMuRMRSA, respectively. The analyses revealed pooled and averaged prevalences of MuRSA, MuRMRSA, HLMuRSA and HLMuRMRSA of 7.6% [95% confidence interval (CI) 6.2-9.0%], 13.8% (95% CI 12.0-15.6%), 8.5% (95% CI 6.3-10.7%) and 8.1% (95% CI 6.8-9.4%), respectively.

CONCLUSION

Overall, these results show a global increase in the prevalence of HLMuRSA and HLMuRMRSA among clinical S. aureus isolates over time. However, there was only a significant increase in the prevalence of MuRMRSA compared with the other categories, especially MuRSA. Since mupirocin remains the most effective antibiotic for MSSA and MRSA decolonisation both in patients and healthcare personnel, a reduction of its effectiveness presents a risk for invasive infection. Monitoring of mupirocin resistance development remains critical.

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.

Bacterial Contamination of Military and Civilian Uniforms in an Emergency Department

INTRODUCTION

The emergency department is a fast-paced, high-volume environment, serving patients with diverse and evolving acuities. Personnel providing direct care are continually exposed to pathogenic microorganisms from patients and everyday surfaces, to which the organisms may spread. Indeed, hospital items-such as electronic devices, stethoscopes, and staff clothing-have demonstrated high rates of contamination. Despite this, policies governing the use, disinfection, and wear of various environmental surfaces remain relaxed, vague, and/or difficult to enforce. This study aimed to examine the bacterial contamination on 2 hospital uniform types in a large military hospital within the emergency department.

METHODS

Environmental sampling of military and civilian nursing staff uniforms was performed on 2 separate occasions. Emergency nurses wore hospital-provided freshly laundered scrubs on the first sampling day and home-laundered personally owned uniforms complicit with ED policy on the second sampling day. Samples were collected by impressing of contact blood agar growth medium at arrival (0 hour), 4 hours, and 8 hours of wear. Microbiological methods were used to enumerate and identify bacterial colonies.

RESULTS

Bacterial contamination of personally owned uniforms was significantly higher than freshly laundered hospital-provided scrubs on 4 different sampling sites and across the span of an 8-hour workday. No significant differences were observed between military and civilian personally owned uniforms. However, several risk factors for nosocomial infection were increased in the military subgroup.

DISCUSSION

Re-evaluating organizational factors (such as uniform policies) that increase the propensity for pathogenic contamination are critical for mitigating the spread and acquisition of multidrug-resistant organisms in the emergency department.

View point: gaps in the current guidelines for the prevention of Methicillin-resistant Staphylococcus aureus surgical site infections

The authors advocate the addition of two preventative strategies to the current United State’s guidelines for the prevention of surgical site infections. It is known that Staphylococcus aureus, including Methicillin-resistant Staphylococcus aureus (MRSA), carriers are at a higher risk for the development of infections and they can easily transmit the organism. The carriage rate of Staph. aureus in the general population approximates 33%. The CDC estimates the carriage rate of MRSA in the United States is approximately 2%. The first strategy is preoperative screening of surgical patients for Staph. aureus, including MRSA. This recommendation is based upon the growing literature which shows a benefit in both prevention of infections and guidance in preoperative antibiotic selection. The second is performing MRSA active surveillance screening on healthcare workers. The carriage rate of MRSA in healthcare workers approximates 5% and there are concerns of transmission of this pathogen to patients. MRSA decolonization of healthcare workers has been reported to approach a success rate of 90%. Healthcare workers colonized with dangerous pathogens, including MRSA, should be assigned to non-patient contact work areas. In addition, there needs to be implemented a safety net for both the worker’s economic security and healthcare. Finally, a reporting system for the healthcare worker acquisition and infections with dangerous pathogens needs to be implemented. These recommendations are needed because Staph. aureus including MRSA is endemic in the United States. Policies regarding endemic pathogens which are to be implemented only upon the occurrence of a facility defined “outbreak” have to be questioned, since absence of infections does not mean absence of transmission. Optimizing these policies will require further research but until then we should error on the side of patient safety.

Epidemiology and microbiological profile comparison between community and hospital acquired infections: A multicenter retrospective study in Lebanon

BACKGROUND

The objective of this study is to identify and characterize the species resistance of different pathogens between community acquired and hospital acquired infections pointing at patients' related independent co-morbidities and socio-demographic factors.

METHODS

It was a retrospective cohort, multicenter study from five private hospitals located in Beirut and Mount Lebanon. Two hundred fifty-eight adult patients were included.

RESULTS

110 Gram negative pathogens and 26 Gram positive pathogens were implicated in hospital acquired infections. The Gram-negative bacteria that showed a positive correlation regarding patient's type of infection were Pseudomonas aeruginosa (12%), Klebsiella pneumoniae (6.2%) and Acinetobacter baumannii (3.1%). These bacteria were more frequent in patients with hospital acquired infections (P=0.002, 0.013 and 0.017 respectively). The ratio of methicillin resistant Staphylococcus aureus, Extended Spectrum Beta Lactamase producing Escherichia coli and K. pneumoniae and multi drug P. aeruginosa showed high significance in hospital acquired infections. The logistic regression, showed a significant relationship between resistant bacteria and age (p<0.001, ORa=5.680, CI [2.344; 13.765]) and immunosuppressed state (p=0.003, ORa=3.137, CI [1.485; 6.630]) and an inverse relationship for Chronic Obstructive Pulmonary Disease (COPD) (p=0.006, ORa=0.403, CI [0.212; 0.765]).

CONCLUSION

Our results confirm that hospital acquired infections/bacteria have higher rates of resistance when compared to community acquired; these rates increase with age, immunosuppression and are inversely proportional with COPD. Therefore, physicians should be aware of patients' comorbidities to properly guide initial therapy.

Role of Daptomycin on Burn Wound Healing in an Animal Methicillin-Resistant Staphylococcus aureus Infection Model

Prolonged hospitalization and antibiotic therapy are risk factors for the development of methicillin-resistant Staphylococcus aureus (MRSA) infections in thermal burn patients. We used a rat model to study the in vivo efficacy of daptomycin in the treatment of burn wound infections by S. aureus, and we evaluated the wound healing process through morphological and immunohistochemical analysis. A copper bar heated in boiling water was applied on a paraspinal site of each rat, resulting in two full-thickness burns. A small gauze was placed over each burn and inoculated with 5 × 10⁷ CFU of S. aureus ATCC 43300. The study included two uninfected control groups with and without daptomycin treatment, an infected control group that did not receive any treatment, and two infected groups treated, respectively, with intraperitoneal daptomycin and teicoplanin. The main outcome measures were quantitative culture, histological evaluation of tissue repair, and immunohistochemical expression of wound healing markers: epidermal growth factor receptor (EGFR) and fibroblast growth factor 2 (FGF-2). The highest inhibition of infection was achieved in the group that received daptomycin, which reduced the bacterial load from 10⁷ CFU/ml to about 10³ CFU/g (P < 0.01). The groups treated with daptomycin showed better overall healing with epithelialization and significantly higher collagen scores than the other groups, and these findings were also confirmed by immunohistochemical data. In conclusion, our results support the hypothesis that daptomycin is an important modulator of wound repair by possibly reducing hypertrophic burn scar formation.

Screening for Methicillin-resistant Staphylococcus aureus in a residence home for elderly in Germany

BACKGROUND

Since many hospitals report high MRSA colonization rates among elderly patients, and because it has been shown that S. aureus colonization increases with advancing age, there are concerns about the introduction of MRSA into nursing homes by MRSA positive patients discharged from hospital. So far, admission screening and subsequent longitudinal screening in residence homes or screening at time of hospital discharge is not established on a regular base. On the other hand, MRSA is acquired frequently during hospital stay. Therefore, the MRSA status of residents remains unclear at the time of re-admission to the residence home. This study was conducted to evaluate the rate of nasal MRSA carriage among residents and nursing staffs of 2 nursing homes for the elderly, the potential acquisition of MRSA during a hospital stay and the feasibility to perform direct screening tests in nursing homes for elderly.

METHODS

In a study period of 5 months, possibility of active PCR-based screening for MRSA has been tested within 2 residence homes for the elderly, with the obligation to avoid inconvenience to the daily working time and working schedule. Residents and staff members were included in the study and positive test results were confirmed with MRSA culture.

RESULTS

Feasibility of active on site screening in a residence home for the elderly using a rapid PCR method has been confirmed. 154 of 156 residents participated on baseline testing for all current and new admitted residents. In 9 participating residents with former unknown status, nasal carriage with MRSA was confirmed (5.8%). Among 32 documented and eligible movements between the nursing home and the hospital, MRSA could be confirmed after return to the residence home in 2 cases (6.3%). MRSA could also be detected in 1 of 14 participating nursing staff (7.1%).

CONCLUSION

Prevalence of MRSA was in a range that has been observed for nursing homes in Germany in previous studies. Residents can acquire MRSA during a hospital stay so that further spread after re-admission into the nursing home cannot be excluded. This study shows that easy to perform direct screening tests in outpatient facilities for nursing of the elderly are promising tools as part of potential new strategies for transmission and infection control in such facilities. Additional studies are needed to investigate if screening followed by interventional hygiene measures can reduce MRSA transmission and infection in such facilities.

Molecular analysis of methicillin-resistant Staphylococcus aureus dissemination among healthcare professionals and/or HIV patients from a tertiary hospital

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial pathogen in community settings. MRSA colonized individuals may contribute to its dissemination; the risk of MRSA infection is increased in human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) patients, although the prevalence of colonization in this group is not well established. The present study addressed this issue by characterizing MRSA isolates from HIV/AIDS patients and their healthcare providers (HCPs) to determine whether transmission occurred between these two populations.

METHODS

A total of 24 MRSA isolates from HIV-infected patients and five from HCPs were collected between August 2011 and May 2013. Susceptibility to currently available antimicrobials was determined. Epidemiological typing was carried out by pulsed-field gel electrophoresis, multilocus sequence typing, and Staphylococcus cassette chromosome (SCCmec) typing. The presence of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) and heterogeneous daptomycin-resistant Staphylococcus aureus (hDRSA) was confirmed by population analysis profile. Isolates characterized in this study were also compared to isolates from 2009 obtained from patients at the same hospital.

RESULTS

A variety of lineages were found among patients, including ST5-SCCmecII and ST30-SCCmecIV. Two isolates were Panton-Valentine leukocidin-positive, and hVISA and hDRSA were detected. MRSA isolates from two HCPs were not related to those from HIV/AIDS patients, but clustered with archived MRSA from 2009 with no known relationship to the current study population.

CONCLUSIONS

ST105-SCCmecII clones that colonized professionals in 2011 and 2012 were already circulating among patients in 2009, but there is no evidence that these clones spread to or between HIV/AIDS patients up to the 7th day of their hospitalization.

MRSA Prevalence and Associated Risk Factors among Health-Care Workers in Non-outbreak Situations in the Dutch-German EUREGIO

Preventing the spread of methicillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities is a major infection control target. However, only a few studies have assessed the potential role of healthcare workers (HCWs) for MRSA dissemination. To investigate the MRSA prevalence and the risk factors for MRSA colonization among HCWs, nasopharyngeal swabs were taken between June 2010 and January 2011 from 726 employees from nine acute care hospitals with different care levels within the German part of a Dutch-German border region (EUREGIO). The isolated MRSA strains were investigated using spa typing. The overall MRSA prevalence among HCWs in a non-outbreak situation was 4.6% (33 of 726), and was higher in nurses (5.6%, 29 of 514) than in physicians (1.2%, 1 of 83). Possible risk factors associated with MRSA colonization were a known history of MRSA carriage and the presence of acne. Intensive contact with patients may facilitate MRSA transmission between patients and HCWs. Furthermore, an accumulation of risk factors was accompanied by an increased MRSA prevalence in HCW.

Hand hygiene using a new hand-cleansing formulation without sanitizers: Effect on Staphylococcus aureus removal and recovery of properties against skin damage

BACKGROUND

Staphylococcus aureus is known to form a biofilm and colonize on damaged skin of the hands. We investigated changes in the quantity of S aureus on the hands and changes in skin damage when using a hand-cleansing formulation with potassium oleate but without a sanitizer (formulation A), which is highly effective in removing S aureus biofilm and causes minimal skin damage.

MATERIAL AND METHODS

The participants (14 medical staff members) used 2 types of hand-cleansing formulations (formulations A and B), each for 4 weeks. S aureus of the hands was cultured from swab samples on agar plates. Surface of hands was measured using an ultraviolet light microscope.

RESULTS AND DISCUSSION

The quantity of S aureus after using formulation A for 4 weeks was 10(1.08 ± 0.05) CFU/mL, a statistically significant decrease from the quantity of S aureus (10(1.59 ± 0.19) CFU/mL) just before use (P = .029). Also, dryness of hand surfaces decreased. With formulation B, the quantity of S aureus did not significantly change from before to after use (P > .05). This presumably occurs because formulation A gently removes S aureus biofilm.

CONCLUSIONS

Formulation A removed S aureus from the hands of participants, and skin damage on the hands improved.

Intermittent nasal carriage with Staphylococcus aureus within a menstrual cycle: Results from a prospective cohort of healthy carriers

Female sex hormones have been related to nasal Staphylococcus aureus carriage in healthy individuals; however, whether nasal staphylococcal carriage varies by menstrual cycle phase remains unknown.We sampled anterior nares of female healthcare workers twice per week for 6 consecutive menstrual cycles. We used mixed-effects Poisson regression models to determine whether intermittent carriage was associated with cycle phases in a given individual. We also performed recurrent event survival analysis to identify host factors linked to incident carriage status.Overall, we collected 754 nasal swabs over 89 consecutive person-cycles from 14 intermittent carriers. In 84 ovulation-defined menstrual cycles (715 swabs), the period prevalence of staphylococcal carriage was 58.7%, 63.1%, and 64.9% in the follicular, periovulatory, and luteal phases, respectively; these differences were not statistically significant after multivariable adjustment and correction for within-person correlation (adjusted relative risk [RR]-periovulatory 0.92, P: 0.30; luteal 1.00, P: 0.98).Using survival analysis, we identified several host factors that were associated with incident loss, gain of colonization, or both. For example, as compared to women aged 20 to 30 years, those aged 30 to 40 years were less likely to losing carriage (hazard ratio [HR]: 0.26, 95% confidence interval [CI]: 0.09, 0.80) but were as likely to regaining carriage (HR: 0.53, 95% CI: 0.21, 1.34). In comparison, being underweight (body mass index [BMI] <18.5) was significantly associated with a higher risk for regaining (HR: 1.95, 95% CI: 1.34, 1.51) and losing (HR: 1.57, 95% CI: 1.16, 2.12) colonization, indicating the alternating tendency for status changes. Personal hygiene behaviors, such as nostril cleansing habit and methods, differentially affected carriers' risk for losing or regaining staphylococcal colonization.Using an intensive sampling scheme, we found that nasal staphylococcal carriage could vary substantially over time in healthy carriers. Yet, such dynamic intraperson changes in carriage status did not depend on menstrual cycle phases but were associated with host age, BMI, and personal hygiene behavior.

Staphylococcus Infections in Pregnancy: Maternal and Neonatal Risks

Staphylococcus aureus is carried by up to one third of the general population; about 2% are carriers for methicillin-resistant S. aureus (MRSA). Infections caused by the antibiotic-resistant form include skin and soft tissue infections, as well as pneumonia, sepsis, and wound infections. Although the risks of hospital-associated systemic infections have decreased with attention to infection control procedures, serious obstetric illness remains a concern. This article describes the range of MRSA infection in the setting of pregnancy and discusses risks to both mother and newborn associated with active MRSA infection during pregnancy and childbirth. Methicillin-resistant S. aureus remains a risk to mothers and newborns, requiring prompt identification and appropriate management.

Interindividual Contacts and Carriage of Methicillin-Resistant Staphylococcus aureus: A Nested Case-Control Study

BACKGROUND

Reducing the spread of multidrug-resistant bacteria in hospitals remains a challenge. Current methods are screening of patients, isolation, and adherence to hygiene measures among healthcare workers (HCWs). More specific measures could rely on a better characterization of the contacts at risk of dissemination.

OBJECTIVE

To quantify how close-proximity interactions (CPIs) affected Staphylococcus aureus dissemination. DESIGN Nested case-control study.

SETTING

French long-term care facility in 2009.

PARTICIPANTS

Patients (n=329) and HCWs (n=261).

METHODS

We recorded CPIs using electronic devices together with S. aureus nasal carriage during 4 months in all participants. Cases consisted of patients showing incident S. aureus colonization and were paired to 8 control patients who did not exhibit incident colonization at the same date. Conditional logistic regression was used to quantify associations between incidence and exposure to demographic, network, and carriage covariables.

RESULTS

The local structure of contacts informed on methicillin-resistant S. aureus (MRSA) carriage acquisition: CPIs with more HCWs were associated with incident MRSA colonization in patients (odds ratio [OR], 1.10 [95% CI, 1.04-1.17] for 1 more HCW), as well as longer CPI durations (1.03 [1.01-1.06] for a 1-hour increase). Joint analysis of carriage and contacts showed increased carriage acquisition in case of CPI with another colonized individual (OR, 1.55 [1.14-2.11] for 1 more HCW). Global network measurements did not capture associations between contacts and carriage.

CONCLUSIONS

Electronically recorded CPIs inform on the risk of MRSA carriage, warranting more study of in-hospital contact networks to design targeted intervention strategies.

The occurrence and dissemination of methicillin and vancomycin-resistant Staphylococcus in samples from patients and health professionals of a university hospital in Recife, State of Pernambuco, Brazil

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) strains have been responsible for many nosocomial outbreaks. Within hospitals, colonized employees often act as reservoirs for the spread of this organism. This study collected clinical samples of 91 patients admitted to the intensive care unit (ICU), hemodialysis/nephrology service and surgical clinic, and biological samples from the nasal cavities of 120 professionals working in those environments, of a University Hospital in Recife, in the State of Pernambuco, Brazil. The main objective of this study was to determine the occurrence and dissemination of methicillin- and vancomycin-resistant Staphylococcus spp.

METHODS

The isolates obtained were tested for susceptibility to oxacillin and vancomycin and detection of the mecA gene. In addition, the isolates were evaluated for the presence of clones by ribotyping-polymerase chain reaction (PCR).

RESULTS

MRSA occurrence, as detected by the presence of the mecA gene, was more prevalent among nursing technicians; 48.1% (13/27) and 40.7% (11/27) of the isolates were from health professionals of the surgical clinic. In patients, the most frequent occurrence of mecA-positive isolates was among the samples from catheter tips (33.3%; 3/9), obtained mostly from the hemodialysis/nephrology service. Eight vancomycin-resistant strains were found among the MRSA isolates through vancomycin screening. Based on the amplification patterns, 17 ribotypes were identified, with some distributed between patients and professionals.

CONCLUSIONS

Despite the great diversity of clones, which makes it difficult to trace the source of the infection, knowledge of the molecular and phenotypic profiles of Staphylococcus samples can contribute towards guiding therapeutic approaches in the treatment and control of nosocomial infections.

Detailed contact data and the dissemination of Staphylococcus aureus in hospitals

Close proximity interactions (CPIs) measured by wireless electronic devices are increasingly used in epidemiological models. However, no evidence supports that electronically collected CPIs inform on the contacts leading to transmission. Here, we analyzed Staphylococcus aureus carriage and CPIs recorded simultaneously in a long-term care facility for 4 months in 329 patients and 261 healthcare workers to test this hypothesis. In the broad diversity of isolated S. aureus strains, 173 transmission events were observed between participants. The joint analysis of carriage and CPIs showed that CPI paths linking incident cases to other individuals carrying the same strain (i.e. possible infectors) had fewer intermediaries than predicted by chance (P < 0.001), a feature that simulations showed to be the signature of transmission along CPIs. Additional analyses revealed a higher dissemination risk between patients via healthcare workers than via other patients. In conclusion, S. aureus transmission was consistent with contacts defined by electronically collected CPIs, illustrating their potential as a tool to control hospital-acquired infections and help direct surveillance.

Recent advances in communication technologies allow monitoring high-resolution contact networks. Close proximity interactions (CPIs) measured by wireless sensors are increasingly used to inform contact networks for the dissemination of pathogens in computational models, although empirical justification is lacking. Here, we conducted a longitudinal prospective study for four months in a hospital, including both patients and healthcare workers (HCWs). High-resolution CPIs were recorded continuously, and participants undertook weekly nasal swabs to detect S. aureus carriage. We set out to test whether the contact network measured by CPIs supported observed transmission episodes. A simulation study was first conducted to choose a test statistic for the association of CPI paths with transmission, showing that CPI path length from transmitter to incident case was the most powerful. Then, we selected patients presenting incident S. aureus colonization in the data. We showed that CPI paths existed to carriers of the same strain, with path lengths significantly shorter than between random pairs of participants, in agreement with the transmission hypothesis. In-hospital contact networks measured by CPIs inform on opportunities for pathogen transmission. These could be used in surveillance systems to help prevent the spread of nosocomial pathogens.

Usefulness of Weekly Methicillin-ResistantStaphylococcus aureusScreening

We evaluated the usefulness of adding weekly methicillin-resistantStaphylococcus aureus(MRSA) screening to our established admission screening and clinical sampling in 4 acute care units of a university hospital. Our results suggest that weekly MRSA screening allows the detection of 56.1% of all cases of hospital-acquired MRSA carriage. These cases would have remained undetected had admission screening and clinical sampling been the only types of surveillance in place.

Methicillin-resistant Staphylococcus sp. colonizing health care workers of a cancer hospital

The aim of the study was to analyze epidemiological and microbiological aspects of oral colonization by methicillin-resistant Staphylococcus of health care workers in a cancer hospital. Interview and saliva sampling were performed with 149 health care workers. Antimicrobial resistance was determined by disk diffusion and minimum inhibitory concentration. Polymerase Chain Reaction, Internal Transcribed Spacer-Polymerase Chain Reaction and Pulsed Field Gel Electrophoresis were performed for genotypic characterization of methicillin-resistant Staphylococcus. Risk factors were determined by logistic regression. Methicillin-resistant Staphylococcus colonization prevalence was 19.5%, denture wearing (p = 0.03), habit of nail biting (p = 0.04) and preparation and administration of antimicrobial (p = 0.04) were risk factors identified. All methicillin-resistant Staphylococcus were S. epidermidis, 94.4% of them had mecA gene. Closely related and indistinguishable methicillin-resistant S. epidermidis were detected. These results highlight that HCWs which have contact with patient at high risk for developing infections were identified as colonized by MRSE in the oral cavity, reinforcing this cavity as a reservoir of these bacteria and the risk to themselves and patients safety, because these microorganisms may be spread by coughing and talking.

MRSA carriage among healthcare workers in non-outbreak settings in Europe and the United States: a systematic review

Abstarct

Knowledge, perceptions, and practices of methicillin-resistant Staphylococcus aureus transmission prevention among health care workers in acute-care settings

BACKGROUND

Health care workers (HCWs) play a critical role in prevention of health care-associated infections such as methicillin-resistant Staphylococcus aureus (MRSA), but glove and gown contact precautions and hand hygiene may not be consistently used with vulnerable patients.

METHODS

A cross-sectional survey of MRSA knowledge, attitudes/perceptions, and practices among 276 medical, nursing, allied health, and support services staff at an acute-care hospital in the eastern United States was completed in 2012. Additionally, blinded observations of hand hygiene behaviors of 104 HCWs were conducted.

RESULTS

HCWs strongly agreed that preventive behaviors reduce the spread of MRSA. The vast majority reported that they almost always engage in preventive practices, but observations of hand hygiene found lower rates of adherence among nearly all HCW groups. HCWs who reported greater comfort with telling others to take action to prevent MRSA transmission were significantly more likely to self-report adherence to recommended practices.

CONCLUSIONS

It is important to reduce barriers to adherence with preventive behaviors and to help all HCWs, including support staff who do not have direct patient care responsibilities, to translate knowledge about MRSA transmission prevention methods into consistent adherence of themselves and their coworkers to prevention guidelines.

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.

Methicillin-resistant Staphylococcus aureus colonization among health care workers in a downtown emergency department in Toronto, Ontario

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) acquired in the community, otherwise known as community-acquired MRSA, has emerged rapidly in recent years. Colonization with MRSA has been associated with an increased risk of symptomatic and serious infections and, in some settings, health care workers (HCWs) exhibit a higher prevalence of MRSA colonization.

OBJECTIVE

To determine MRSA colonization in emergency department (ED) HCWs in the setting of a moderate prevalence of MRSA in skin and soft tissue infections.

METHODS

The present study was conducted at a downtown ED in Toronto, Ontario. ED HCWs completed a brief questionnaire and swabs were taken from one anterior nare, one axilla and any open wounds (if present). Swabs were processed using standard laboratory techniques.

RESULTS

None of the 89 staff (registered nurses [n=55], physicians [n=15], other [n=19]) were MRSA positive and 25 (28.1%) were colonized with methicillin-susceptible S aureus.

CONCLUSIONS

Contrary to common belief among HCWs and previous studies documenting MRSA colonization of HCWs, MRSA colonization of this particular Canadian ED HCW cohort was very low and similar to that of the local population.

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.

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.

A short-term, multicomponent infection control program in nursing homes: a cluster randomized controlled trial

OBJECTIVES

To assess the impact of a hygiene-encouragement program on reducing infection rates (primary end point) by 5%.

DESIGN

A cluster randomized study was carried out over a 5-month period.

SETTINGS AND PARTICIPANTS

Fifty nursing homes (NHs) with 4345 beds in France were randomly assigned by stratified-block randomization to either a multicomponent intervention (25 NHs) or an assessment only (25 NHs).

INTERVENTION

The multicomponent intervention was targeted to caregivers and consisted of implementing a bundle of infection prevention consensual measures. Interactive educational meetings using a slideshow were organized at the intervention NHs. The NHs were also provided with color posters emphasizing hand hygiene and a kit that included hygienic products such as alcoholic-based hand sanitizers. Knowledge surveys were performed periodically and served as reminders.

MEASUREMENTS

The primary end point was the total infection rate (urinary, respiratory, and gastrointestinal infections) in those infection cases classified either as definite or probable. Analyses corresponded to the underlying design and were performed according to the intention-to-treat principle. This study was registered (#NCT01069497).

RESULTS

Forty-seven NHs (4515 residents) were included and followed. The incidence rate of the first episode of infection was 2.11 per 1000 resident-days in the interventional group and 2.15 per 1000 resident-days in the control group; however, the difference between the groups did not reach statistical significance in either the unadjusted (Hazard Ratio [HR] = 1.00 [95% confidence interval (CI) 0.89-1.13]; P = .93]) or the adjusted (HR = 0.99 [95% CI 0.87-1.12]; P = .86]) analysis.

CONCLUSION

Disentangling the impact of this type of intervention involving behavioral change in routine practice in caregivers from the prevailing environmental and contextual determinants is often complicated and confusing to interpret the results.

Emergence of hospital- and community-associated panton-valentine leukocidin-positive methicillin-resistant Staphylococcus aureus genotype ST772-MRSA-V in Ireland and detailed investigation of an ST772-MRSA-V cluster in a neonatal intensive care unit

Sequence type 22 (ST22) methicillin-resistant Staphylococcus aureus (MRSA) harboring staphylococcal cassette chromosome mec (SCCmec) IV (ST22-MRSA-IV) has predominated in Irish hospitals since the late 1990s. Six distinct clones of community-associated MRSA (CA-MRSA) have also been identified in Ireland. A new strain of CA-MRSA, ST772-MRSA-V, has recently emerged and become widespread in India and has spread into hospitals. In the present study, highly similar MRSA isolates were recovered from seven colonized neonates in a neonatal intensive care unit (NICU) in a maternity hospital in Ireland during 2010 and 2011, two colonized NICU staff, one of their colonized children, and a NICU environmental site. The isolates exhibited multiantibiotic resistance, spa type t657, and were assigned to ST772-MRSA-V by DNA microarray profiling. All isolates encoded resistance to macrolides [msr(A) and mpb(BM)] and aminoglycosides (aacA-aphD and aphA3) and harbored the Panton-Valentine leukocidin toxin genes (lukF-PV and lukS-PV), enterotoxin genes (sea, sec, sel, and egc), and one of the immune evasion complex genes (scn). One of the NICU staff colonized by ST772-MRSA-V was identified as the probable index case, based on recent travel to India. Seven additional hospital and CA-ST772-MRSA-V isolates recovered from skin and soft tissue infections in Ireland between 2009 and 2011 exhibiting highly similar phenotypic and genotypic characteristics to the NICU isolates were also identified. The clinical details of four of these patients revealed connections with India through ethnic background or travel. Our study indicates that hospital-acquired and CA-ST772-MRSA-V is currently emerging in Ireland and may have been imported from India on several occasions.

Newly cleaned physician uniforms and infrequently washed white coats have similar rates of bacterial contamination after an 8-hour workday: a randomized controlled trial

BACKGROUND

Governmental agencies in the United Kingdom and Scotland have recently instituted guidelines banning physicians' white coats and the wearing of long-sleeved garments to decrease nosocomial transmission of bacteria.

OBJECTIVE

Our aim was to compare the degree of bacterial and methicillin-resistant Staphylococcus aureus contamination of physicians' white coats with that of newly laundered, standardized short-sleeved uniforms after an 8-hour workday and to determine the rate at which bacterial contamination of the uniform ensued.

DESIGN

The design was a prospective, randomized controlled trial.

SETTING

The setting was a university-affiliated public safety-net hospital.

PARTICIPANTS

One hundred residents and hospitalists on an internal medicine service participated.

INTERVENTION

Subjects wore either a physician's white coat or a newly laundered short-sleeved uniform.

MEASUREMENTS

Bacterial colony count and the frequency with which methicillin-resistant Staphylococcus aureus was cultured from both garments over time were measured.

RESULTS

No statistically significant differences were found in bacterial or methicillin-resistant Staphylococcus aureus contamination of physicians' white coats compared with newly laundered short-sleeved uniforms or in contamination of the skin at the wrists of physicians wearing either garment. Colony counts of newly laundered uniforms were essentially zero, but after 3 hours of wear they were nearly 50% of those counted at 8 hours.

CONCLUSIONS

Bacterial contamination occurs within hours after donning newly laundered short-sleeved uniforms. After 8 hours of wear, no difference was observed in the degree of contamination of uniforms versus infrequently laundered white coats. Our data do not support discarding long-sleeved white coats for short-sleeved uniforms that are changed on a daily basis.

The role of pre-operative assessment and ringfencing of services in the control of methicillin resistant Staphlococcus aureus infection in orthopaedic patients

BACKGROUND

MRSA is a major economic and health issue internationally and as such is of particular importance in the appropriate management of orthopaedic patients. Bone, joint and implant infection can lead to unfavourable outcomes with a long protracted in hospital stay inevitable. The cost for the patient, the hospital and society are substantial.

MATERIALS AND METHODS

This study was a review of a prospectively maintained database from our unit over three time points from 2005 to 2007. At each time point a new infection control measure was implemented in an effort to reduce MRSA infections. Total rates of MRSA infection and colonisation in all orthopaedic patients were recorded, before and after separation of trauma and elective services, and after the introduction of a screening pre assessment clinic.

RESULTS

12259 orthopaedic patients were reviewed over the three years. The mean age of MRSA infected patients was 71. A higher proportion of female patients were infected than male patients. The mean length of stay for infected patients was 23.4 days. The rate of infection dropped from 0.49% in 2005 to 0.24%in 2007. After the introduction of these measures there was a substantial reduction in organ space and deep tissue infections.

CONCLUSION

The separation of emergency and elective orthopaedic services coupled with effective pre-operative screening has resulted in a significant reduction in MRSA infection despite an ever increasing prevalance.

Outbreak of community-acquired methicillin-resistant Staphylococcus aureus skin infections among health care workers in a cancer center

BACKGROUND

The incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) soft tissue infections is rising. However, CA-MRSA outbreaks among health care workers (HCWs) are rarely reported. We describe 3 clusters of CA-MRSA soft tissue infections among HCWs and the subsequent transmission to a patient.

METHODS

The first cluster of boils occurred in 4 employees who worked in the ambulatory treatment clinic (area A) and 1 patient (PA1) who frequently visited area A. Three employees (EA1, EA2, and EA3) and PA1 had positive cultures. Twelve employees in 2 geographically separate diagnostic imaging areas (areas B and C) reported recent or current boils of whom EB1, EB2, EB3, and EC1 had positive cultures. Molecular subtyping using pulse-field gel electrophoresis (PFGE) was performed on all 8 isolates and confirmed by the Centers for Disease Control and Prevention laboratory.

RESULTS

Relatedness of the MRSA strain was confirmed by PFGE in 7 of 8 isolates. Only EB3 was not related to the prototype CA-MRSA strain. All 7 related MRSA strains contained the typical genetic organization of staphylococcal cassette chromosome (SCC)-mec type IVa plus genes encoding Panton-Valentine Leukocidin. EB3's strain contained SCC-mec type II and was Panton-Valentine Leukocidin negative. A total of 171 questionnaires was sent. Nine of the 85 HCWs who responded reported a recent or current history of boils. Infection control conducted an education program for employees in areas A, B, and C.

CONCLUSION

Early identification and control of CA-MRSA infections among HCWs is important to limit horizontal transmission to patients. Future efforts should include educational programs and guidelines for reporting and treating HCWs with MRSA infections.

Detection and characterization of an ST97-SCCmec-V community-associated meticillin-resistant Staphylococcus aureus clone in a neonatal intensive care unit and special care baby unit

A total of 29 meticillin-resistant Staphylococcus aureus (MRSA) isolates were obtained from 15 neonates and three healthcare workers (HCWs) in a neonatal intensive care unit (NICU) and special care baby unit (SCBU) and four patients in a medical ward of a Kuwait hospital between 10 and 30 April 2007. The isolates were characterized using antibiogram results, coagulase gene RFLP (coa-RFLP), PFGE, staphylococcal cassette chromosome mec (SCCmec) typing and multilocus sequence typing (MLST). All isolates were assessed for the carriage of Panton-Valentine leukocidin (PVL) and arginine catabolic mobile element (ACME) genes. The isolates belonged to three SCCmec types, six coa-RFLP types, six pulsotypes and six sequence types. One isolate was positive for PVL. None were positive for ACME. All MRSA isolates from the 15 neonates were phenotypically and genetically different from the MRSA isolates obtained from HCWs and those from patients in other wards. They were resistant to gentamicin, kanamycin and fusidic acid, had identical coa-RFLP and PFGE patterns, carried the type V SCCmec element and belonged to MLST sequence type ST97. The results showed the transmission of a rare clone of community-associated MRSA belonging to ST97 with the SCCmec-V genotype among neonates in a NICU and SCBU.

Should healthcare workers be screened routinely for meticillin-resistant Staphylococcus aureus? A review of the evidence

Meticillin-resistant Staphylococcus aureus (MRSA) is considered endemic in the UK National Health Service (NHS), and routine MRSA screening of hospital inpatients has recently been introduced in both Scotland and England. The UK National Screening Committee states that public pressure for widening the eligibility criteria of a proposed screening programme should be anticipated and any related decisions scientifically justifiable. A literature review was conducted to examine whether MRSA screening in Scotland should be expanded to include the routine screening of healthcare workers (HCWs). There are no published prevalence studies reporting the overall MRSA carriage rate in HCWs in NHS hospitals. Estimates of HCW carriage from the worldwide literature vary widely depending on the country, hospital specialty and setting (endemic, non-endemic or outbreak). Recent studies conducted in endemic hospital settings report non-outbreak carriage rates of 0-15%. The role of HCW carriage in the transmission of MRSA is not well understood. Persistent carriage could act as a reservoir for infection and HCWs have been implicated as the source in a number of published outbreak reports. There are no published controlled trials examining the impact of routine HCW screening as an intervention in the prevention and control of MRSA infections in the endemic hospital setting. Most of the evidence for HCW screening comes from outbreak reports where the outbreak was brought to an end following the introduction of staff screening as part of a suite of infection control measures. Further research is required before a recommendation could be made to introduce routine MRSA screening of HCWs in the NHS in Scotland.

Staphylococcus aureus detection in the mouth of housekeepers

This study assessed the prevalence of colonization by Staphylococcus aureus in hospital housekeepers, and their knowledge and beliefs regarding this problem. Three saliva samples were collected and a questionnaire regarding knowledge and beliefs was applied. Of the 92 workers, 63 (68.5%) participated in the study; 20 were not and 43 were colonized; 13 by methicillin resistant Staphylococcus aureus and 30 by methicillin sensitive Staphylococcus aureus. Persistent carrier status of methicillin resistant Staphylococcus aureus was detected in 15.4% of cases. Low knowledge and perception of occupational risk were observed. The mouth was identified as an important reservoir of methicillin resistant Staphylococcus aureus. Analyzing knowledge and beliefs, as well as the state of carrier, is an important strategy to be added to educational actions for the prevention of workers' colonization.

Epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization among patients and healthcare workers in a Portuguese hospital: a pre-intervention study toward the control of MRSA

This two-year study investigated the epidemiology of nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) among patients and healthcare workers (HCWs) in two wards with a high frequency of MRSA isolation, at Hospital Geral de Santo António (HGSA), Portugal. Three point-prevalence surveys per year were carried out. A case-control approach was used to identify potential risk factors associated with MRSA carriage among patients. Incidence rates and risk factors of MRSA carriage among HCWs who were negative at the baseline observation were estimated. Prevalence of MRSA carriage among 276 patients screened was 5.1%. Admission to HGSA or attendance to the Diabetic Foot Outpatient Unit (DFOU) of HGSA within the past 12 months, and previous MRSA isolation were significant risk factors for MRSA carriage. Among HCWs (n = 126), the prevalence of MRSA carriage was 4.8% and the incidence rate was 61/1000 person-years. Nurses and nurse aids were the HCW categories with the highest risk of becoming colonized with MRSA over time (p = 0.01). One HCW chronically colonized was detected. Molecular typing revealed a clonal identity for isolates recovered from patients and HCWs of the same wards, with 88.6% of isolates belonging to the EMRSA-15 (ST22-MRSA-IV) clone.

Active surveillance testing and decontamination strategies in intensive care units to reduce methicillin-resistant Staphylococcus aureus infections

BACKGROUND

Active surveillance testing (AST) and decontamination strategies (DS) using a topical methicillin-resistant Staphylococcus aureus (MRSA) cleansing agent was introduced in July 2007 in a medical intensive care unit (MICU) and a surgical ICU (SICU) of a tertiary care hospital to reduce the incidence of MRSA infection.

METHODS

Data on ICU admissions between July 1, 2007, and June 30, 2008, was analyzed. All subjects, excluding known MRSA status, had an ICU length of stay (LOS) of more than 24 hours and nasal swabs performed on ICU admission, every 7 days during the ICU stay, and on discharge. MICU and SICU specimens were sent for culture and in-house real-time polymerase chain reaction, respectively. MRSA-colonized (MRSAc) patients were subjected to contact isolation precautions and DS for 5 days or until ICU discharge. Data recorded included demographics, LOS, and antibiotic use. Results were analyzed using SPSS. Control charts were used to determine special cause variation.

RESULTS

Of 653 eligible patients admitted to the ICU, 85 (13%) were determined to be MRSAc on ICU admission. A further 15% (52 of 351) were determined to be MRSAc during the ICU stay or at discharge. Thus, AST detected MRSA in at least 137 of the 653 patients (21.0%). In contrast, clinical cultures for MRSA were positive in only 12 patients (1.8%). Compared with noncolonized patients, MRSAc patients at any screening point had a longer pre-ICU LOS (P =.001), received more antibiotics (P = .004), and had a longer ICU LOS (P = .003). Compared with the preintervention period of July 2006 to June 2007, there was no significant reduction in mean MRSA infection incidence rate in both ICUs (3.8 to 3.0 per 1000 patient-days [P = .057] in the SICU and 1.4 to 1.7 per 1000 patient-days in the MICU) following intervention.

CONCLUSIONS

In ICUs, AST detected 11 times more MRSA than clinical cultures. The lack of reduction in MRSA infection rates in the ICUs does not negate the roles of AST and DS, but does argue for better study design and outcome measures like MRSA transmission incidence, which perhaps would have demonstrated a true benefit of AST and DS.

Cluster randomised controlled trial of an infection control education and training intervention programme focusing on meticillin-resistant Staphylococcus aureus in nursing homes for older people

The aim of this cluster randomised controlled trial was to test the impact of an infection control education and training programme on meticillin-resistant Staphylococcus aureus (MRSA) prevalence in nursing homes. Nursing homes were randomised to intervention (infection control education and training programme; N=16) or control (usual practice continued; N=16). Staff in intervention homes were educated and trained (0, 3 and 6 months) in the principles and implementation of good infection control practice with infection control audits conducted in all sites (0, 3, 6 and 12 months) to assess compliance with good practice. Audit scores were fed back to nursing home managers in intervention homes, together with a written report indicating where practice could be improved. Nasal swabs were taken from all consenting residents and staff at 0, 3, 6 and 12 months. The primary outcome was MRSA prevalence in residents and staff, and the secondary outcome was a change in infection control audit scores. In all, 793 residents and 338 staff were recruited at baseline. MRSA prevalence did not change during the study in residents or staff. The relative risk of a resident being colonised with MRSA in an intervention home compared with a control home at 12 months was 0.99 (95% confidence interval: 0.69, 1.42) after adjustment for clustering. Mean infection control audit scores were significantly higher in the intervention homes (82%) compared with the control homes (64%) at 12 months (P<0.0001). Consideration should be given to other approaches which may help to reduce MRSA in this setting.

MRSA in dermatology - Prospective epidemiological study in employees and patients of a dermatological department of a university hospital

BACKGROUND

In recent years, the prevalence of MRSA has increased worldwide. There is a lack of systematic epidemiological studies evaluating the prevalence of MRSA in dermatology in Germany.

OBJECTIVE

What is the prevalence of MRSA in the employees and hospitalized patients in a dermatological department? What dermatological diagnoses have the highest risk for MRSA?

PATIENTS AND METHODS

Nasal swabs taken twice (at admission and discharge) from all consenting hospitalized patients and once from all consenting employees were analyzed for MRSA.

RESULTS

Analysis von 798 swabs (715 patients, 83 employees). Detection of MRSA in 31 swabs (MRSA rates: all = 4.3 %, patients = 3.7 %, employees = 4.8 %). Patients with a chronic leg ulcer had a significantly increased risk for MRSA (p = 0.03). Increased MRSA rates without statistical significance were found for men, patients with at least one hospitalization during the last 12 weeks and a hospitalization of at least 5 days. None of the patients with psoriasis had MRSA.

CONCLUSIONS

In comparison to international studies, the prevalence of MRSA in the current study is in the lower third. In dermatology, patients with a chronic leg ulcer have an increased risk for MRSA and should be screened at admission. A general screening for MRSA seems to be not reasonable in view of the low MRSA rates in the investigated department.

Emerging infections in burns

BACKGROUND

Patients who suffer severe burns are at higher risk for local and systemic infections. In recent years, emerging resistant pathogens have forced burn care providers world wide to search for alternative forms of treatment. Multidrug-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter spp., and various fungal strains have been the major contributors to the increase in morbidity and mortality rates. Multi-drug-resistant S. aureus remains the major cause of gram-positive burn wound infections world wide. Treatment strategies include rigorous isolation protocols and new types of antibiotics where necessary.

METHODS

We reviewed 398 severely burned patients (burns >40% total body surface area [TBSA]) admitted to our hospital between 2000 and 2006. Patients who did not contract multi-drug-resistant gram-negative organisms during their hospital course and received our standard antibiotic regimen-vancomycin and piperacillin/tazobactam-served as controls (piperacillin/tazobactam; n = 280). The treatment group consisted of patients who, during their acute hospital stay, developed infections with multi-drug-resistant gram-negative pathogens and were treated with vancomycin and colistin for at least three days (colistin; n = 118).

RESULTS

Gram-negative organisms continue to cause the most severe infections in burn patients. Colistin has re-emerged as a highly effective antibiotic against multiresistant Pseudomonas and Acinetobacter infections of burns. Patients who required colistin therapy had a significantly larger average total and full-thickness burn than patients treated with piperacillin/tazobactam and vancomycin, and the mortality rate was significantly higher in the colistin group (p < 0.05). However, there was no significant difference between the colistin and piperacillin/tazobactam groups in the incidence of neurotoxicity, hepatic toxicity, or nephrotoxicity. The main fungal pathogens in burn patients are Candida spp., Aspergillus spp., and Fusarium spp. A definitive diagnosis is more difficult to obtain than in bacterial infections. Amphotericin B and voriconazole remain the two most important anti-fungal substances in our practice.

CONCLUSIONS

Innovations in fluid management, ventilatory support, surgical care, and antimicrobial therapy have contributed to a significant reduction in morbidity and mortality rates in burn patients. Vancomycin and clindamycin are the two most important reserve antibiotics for methicillin-resistant Staphylococcus aureus infection. Oxazolidinones and streptogramins have showed high effectiveness against gram-positive infections. Colistin has re-emerged as a highly effective antibiotic against multiresistant Pseudomonas and Acinetobacter infections. Current challenges include Candida, Aspergillus, and molds. The development of new agents, prudent and appropriate use of antibiotics, and better infection control protocols are paramount in the ongoing battle against multi-resistant organisms.

Rapid MRSA test in exposed persons: costs and savings in hospitals

OBJECTIVE

To study a rapid Xpert polymerase chain reaction (PCR) method in detecting methicillin-resistant Staphylococcus aureus (MRSA) in patients and healthcare workers (HCW) exposed to MRSA, and to estimate savings associated to isolation or work restriction.

METHODS

A test set of four double (one for the growth and one for the rapid test) pre-wet swabs from the nose, throat, hands/wrists and perineum was studied by a growth method and by the Xpert MRSA test.

RESULTS

The total correspondence between the growth and the rapid test was 92.8%. The overall sensitivity, specificity, positive and negative predictive values were for the Xpert MRSA test: 87%, 99.6%, 68.5% and 99.9%, and for the growth test: 76%, 100%, 100%, and 99.8%, assuming a prevalence of MRSA of 0.01%. Among the MRSA positive persons, the Xpert and growth tests detected MRSA in 44.6% and 40% of nose samples, respectively, 38.2% and 45.5% throat samples, 30.8% and 11.5% hands/wrists samples, 44% and 38% perineum samples, and in 81.8% and 77.3% wound samples, respectively. By combining four anatomical sites, the detection rate increased to 87.5% by both methods. The cost for each Xpert and growth test was euro50 and euro6.25, respectively. The rapid test would save at least euro925 per exposed HCW and euro550 per patient that were MRSA negative.

CONCLUSION

The MRSA Xpert test is easy to perform, has a high negative predictive value, and may be used to control healthcare workers and patients exposed to MRSA. Sampling from multiple anatomical locations is recommended. Still, more then 10% of MRSA positive cases may not be found.

Methicillin-resistant Staphylococcus aureus colonization of house officers

We performed a prospective prevalence survey of methicillin-resistant Staphylococcus aureus (MRSA) carriage in the nares of 50 medical and 50 surgical house officers. None of the 50 internal medicine house officers and 5 of the 50 general surgery house officers had MRSA nares colonization (P = .03). None of the MRSA isolates recovered from the surgical house officers were identical.

Vaccination as infection control: a pilot study to determine the impact of Staphylococcus aureus vaccination on nasal carriage

BACKGROUND

There is a critical need for an effective Staphylococcus aureus vaccine for the prevention of staphylococcal disease. In this study, we investigated the impact of S. aureus conjugate vaccine comprised of capsular polysaccharides 5 and 8 (CP5, CP8) on nasal colonization with S. aureus.

METHODS

Healthy adults recruited from one academic medical center to participate in a lot consistency trial of StaphVAX (S. aureus capsular polysaccharide 5 and 8 conjugate vaccine) were assessed for S. aureus nasal colonization at two weekly points prior to vaccination and again at six weeks post-vaccination. Serum anti-capsular antibody titers to CP5 and CP8 were obtained prior to vaccination and 42 days post-vaccination and measured by ELISA.

RESULTS

Thirty of 88 enrolled subjects (34%) had S. aureus isolated from at least one of the pre-immunization cultures. Of these, 20 were termed persistent carriers due to two positive cultures one week apart; 19 of the 20 were evaluable at Day 42. Baseline anti-CP8 concentrations were higher in persistent carriers of CP8+ S. aureus; however, baseline anti-CP5 levels were not significantly higher in individuals persistently colonized with CP5+ S. aureus. Statistically significant rises in antibody concentrations were noted after vaccination. At Day 42, 14 of 19 persistent carriers remained colonized; 5 subjects did not have evidence of S. aureus colonization. Ten additional subjects were positive for S. aureus at Day 42 who were not persistently colonized at baseline. Serum antibody concentrations were not statistically different between those with persistent carriage vs. those that lost carriage or those with newly acquired carriage.

CONCLUSIONS

Immune responses to vaccine were brisk and comparable in subjects with or without persistent colonization. Despite a substantial rise in anti-CP5 and anti-CP8 antibody concentrations post-vaccination, S. aureus nasal colonization rates did not significantly change.

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

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

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

INTRODUCTION

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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