Eradication of colonization by methicillin-resistant Staphylococcus aureus by using oral minocycline-rifampin and topical mupirocin

How often are health care personnel hands colonized with multidrug- resistant organisms? A systematic review and meta-analysis

BACKGROUND

Hands of health care personnel (HCP) can transmit multidrug-resistant organisms (MDROs), resulting in infections. Our aim was to determine MDRO prevalence on HCP hands in adult acute care and nursing facility settings.

METHODS

A systematic search of PubMed/MEDLINE, Web of Science, CINAHL, Embase, and Cochrane CENTRAL was performed. Studies were included if they reported microbiologic culture results following HCP hands sampling; included prevalent MDROs, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus, Clostridium difficile, Acinetobacter baumannii, or Pseudomonas aeruginosa, and were conducted in acute care or nursing facility settings.

RESULTS

Fifty-nine articles comprising 6,840 hand cultures were included. Pooled prevalence for MRSA, P aeruginosa, A baumannii, and vancomycin-resistant Enterococcus were 4.26%, 4.59%, 6.18%, and 9.03%, respectively. Substantial heterogeneity in rates of pathogen isolation were observed across studies (I² = 81%-95%). Only 4 of 59 studies sampled for C difficile, with 2 of 4 finding no growth. Subgroup analysis of MRSA revealed the highest HCP hand contamination rates in North America (8.28%). Sample collection methods used were comparable for MRSA isolation (4%-7%) except for agar direct contact (1.55%).

CONCLUSIONS

Prevalence of common MDROs on HCP hands vary by pathogen, care setting, culture acquisition method, study design, and geography. When obtained at an institutional level, these prevalence data can be utilized to enhance knowledge, practice, and research to prevent health care-associated infections.

Bacteriology of pressure ulcers in individuals with spinal cord injury: What we know and what we should know

Individuals with spinal cord injury (SCI) are at increased risk for the development of pressure ulcers. These chronic wounds are debilitating and contribute to prolonged hospitalization and worse medical outcome. However, the species of bacteria and the role that specific species may play in delaying the healing of chronic pressure ulcers in the SCI population has not been well characterized. This study will review the literature regarding what is known currently about the bacteriology of pressure ulcers in individuals with SCI. An electronic literature search of MEDLINE (1966 to February 2014) was performed. Eleven studies detailing bacterial cultures of pressure ulcers in the SCI population met inclusion criteria and were selected for review. Among these studies, bacterial cultures were often polymicrobial with both aerobic and anaerobic bacteria identified with culture techniques that varied significantly. The most common organisms identified in pressure ulcers were Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, and Enterococcus faecalis. In general, wounds were poorly characterized with minimal to no physical description and/or location provided. Our present understanding of factors that may alter the microbiome of pressure ulcers in individuals with SCI is quite rudimentary, at best. Well-designed studies are needed to assess appropriate wound culture technique, the impact of bacterial composition on wound healing, development of infection, and the optimum medical and surgical approaches to wound care.

Effect of Vancomycin Therapy for Osteomyelitis on Colonization by Methicillin-ResistantStaphylococcus aureus: Lack of Emergence of Glycopeptide Resistance

Background:

In treating orthopedic infections, the long-term impact of vancomycin therapy on colonization by methicillin-resistantStaphylococcus aureus(MRSA) and the emergence of vancomycin-intermediate S.aureusis unknown.

Design:

Prospective surveillance of the effect of long-term vancomycin therapy on colonization by MRSA and the emergence of vancomycin-intermediateS. aureus.

Methods:

Thirty-four patients with MRSA osteomyelitis that was microbiologically documented were longitudinally observed for the emergence of vancomycin-intermediate S.aureusat 3 body sites (wound, anterior nares, and groin) during the initial period of vancomycin therapy and at the 2-month follow-up. Twenty patients received the standard dose (20 mg/kg/d) for 34 ± 6 days and 14 patients received a high dose (40 mg/kg/d) of vancomycin for 37 ± 9 days.

Results:

During vancomycin treatment, global MRSA carriage (all body sites) fell from 100% to 25% in the group of patients receiving the standard dose of vancomycin, and from 100% to 40% in the group receiving the high dose. During the 2-month follow-up period after vancomycin therapy, global MRSA carriage increased from 25% to 55% in the group receiving the standard dose and decreased from 43% to 36% in the group receiving the high dose.

Conclusion:

Therapy with a high dose of vancomycin contributes to the sustained eradication of MRSA carriage without promoting the emergence of glycopeptide resistance.

Prevention of methicillin-resistant Staphylococcus aureus infections in spinal cord injury units

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) health care-associated infections (HAIs) are a concern in the 22 acute care Veterans Affairs (VA) spinal cord injury units where patients with unique rehabilitation and medical needs and a high risk of infection are treated.

METHODS

A bundle was implemented in VA spinal cord injury units consisting of nasal surveillance for MRSA on admission/in-hospital transfer/discharge, contact precautions for patients colonized or infected with MRSA, an emphasis on hand hygiene, and an institutional culture change where infection control became everyone's responsibility.

RESULTS

From October 2007, through June 2011, there were 51,627 admissions/transfers/discharges and 816,254 patient-days of care in VA spinal cord injury units. The percentage of patients screened increased to >95.0%. The mean admission MRSA prevalence was 38.6% ± 19.1%. Monthly HAI rates declined 81% from 1.217 per 1,000 patient-days to 0.237 per 1,000 patient-days (P < .001). Bloodstream infections declined by 100% (P = .002), skin and soft-tissue infections by 60% (P = .007), and urinary tract infections by 33% (P = .07).

CONCLUSION

Universal surveillance, contact precautions, hand hygiene, and an institutional culture change was associated with significant declines in MRSA HAIs in a setting with a high prevalence of MRSA colonization and a high risk for infection.

Minocycline: old and new therapeutic uses

Since the introduction of minocycline HCl in the late 1960's, it has been used for disease states that have ranged from typical community-acquired infectious diseases to others that are non-infectious, such as resistant rheumatoid arthritis. Owing to its high penetration characteristics throughout the body, minocycline can be used in the treatment of a wide variety of extracellular and intracellular pathogens. This review examines the known and potential therapeutic uses of minocycline in a clinical setting.

Antibiotic Treatment of Multidrug-Resistant Organisms in Cystic Fibrosis

Respiratory tract infection with eventual respiratory failure is the major cause of morbidity and mortality in cystic fibrosis (CF). Infective exacerbations need to be treated promptly and effectively to minimize potentially accelerated attrition of lung function. The choice of antibiotic depends on in vitro sensitivity patterns. However, physicians treating patients with CF are increasingly faced with infection with multidrug-resistant isolates of Pseudomonas aeruginosa. In addition, innately resistant organisms such as Burkholderia cepacia complex, Stenotrophomonas maltophilia and Achromobacter (Alcaligenes) xylosoxidans are becoming more prevalent. Infection with methicillin-resistant Staphylococcus aureus (MRSA) is also a problem. These changing patterns probably result from greater patient longevity and increased antibiotic use for acute exacerbations and maintenance care. Multidrug-resistant P. aeruginosa infection may be treated successfully by using two antibiotics with different mechanisms of action. In practice antibiotic choices have usually been made on a best-guess basis, but recent research suggests that more directed therapy can be achieved through the application of multiple-combination bactericidal testing (MCBT). Aerosol delivery of tobramycin for inhalation solution achieves high endobronchial concentrations that may overcome bacterial resistance as defined by standard laboratory protocols. Resistance to colistin is rare and this antibiotic should be seen as a valuable second-line drug to be reserved for multidrug-resistant P. aeruginosa. The efficacy of new antibiotic groups such as the macrolides needs to be evaluated.CF units should adopt strict segregation policies to interrupt person-to-person spread of B. cepacia complex. Treatment of panresistant strains is difficult and often arbitrary. Combination antibiotic therapy is recommended, usually tobramycin and high-dose meropenem and/or ceftazidime, but the choice of treatment regimen should always be guided by the clinical response.The clinical significance of S. maltophilia, A. xylosoxidans and MRSA infection in CF lung disease remains uncertain. If patients show clinical decline and are chronically colonized/infected with either of the former two pathogens, treatment is recommended but efficacy data are lacking. There are defined microbiological reasons for attempting eradication of MRSA but there are no proven deleterious effects of this infection on lung function in patients with CF. Various treatment protocols exist but none has been subject to a randomized, controlled trial. Multidrug-resistant microorganisms are an important and growing issue in the care of patients with CF. Each patient infected with such strains should be assessed individually and antibiotic treatment planned according to in vitro sensitivity, patient drug tolerance, and results of in vitro studies which may direct the physician to antibiotic combinations most likely to succeed.

Combined topical and oral antimicrobial therapy for the eradication of methicillin-resistant Staphylococcus aureus (MRSA) colonization in hospitalized patients

OBJECTIVE

How to eradicate methicillin-resistant Staphylococcus aureus (MRSA) colonization in hospitalized patients is uncertain. We reviewed our experience with MRSA decolonization therapy in hospitalized patients.

SETTING

An 1100-bed, university-affiliated tertiary care teaching hospital in Toronto, Ontario.

DESIGN

Retrospective chart review of 207 adult inpatients with MRSA colonization hospitalized between February 1996 and March 1999.

INTERVENTIONS

All patients with MRSA colonization were assessed for possible decolonization therapy with a combination of 4% chlorhexidine soap for bathing and washing, 2% mupirocin ointment applied to the anterior nares three times/day, rifampin (300 mg twice daily) and either trimethoprim/sulfamethoxazole (160 mg/800 mg twice daily) or doxycycline (100 mg twice daily). This treatment was given for seven days.

RESULTS

A total of 207 hospitalized patients with MRSA colonization were identified and 103 (50%) received decolonization therapy. Patients who received decolonization therapy were less likely than untreated patients to have intravenous (P=0.004) or urinary catheters (P<0.001), or extranasal sites of colonization (P=0.001). Successful decolonization was achieved in 90% of the 43 patients who were available for at least three months of follow-up.

CONCLUSIONS

Combined topical and oral antimicrobial therapy was found to be effective in eradicating MRSA colonization in selected hospitalized patients, especially those without indwelling medical devices or extranasal sites of colonization.

Decolonization of methicillin-resistant Staphylococcus aureus during routine hospital care: Efficacy and long-term follow-up

BACKGROUND/OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) colonization is associated with a significant risk of subsequent MRSA infection in the hospital setting. The use of decolonization as an infection control strategy remains highly controversial despite publications evaluating more than 40 different decolonization regimens over the past 60 years. The present study describes the benefits and potential drawbacks of such an approach in the patient population.

METHODS

A retrospective cohort study was performed to assess the efficacy and subsequent outcome for patients with newly identified MRSA colonization at the Horizon Health Network in Moncton, New Brunswick.

RESULTS

A total of 241 patients with MRSA colonization or infection during the study period (2000 to 2005 inclusive) were identified. Eighty-nine MRSA-positive patients were decolonized according to a standardized regimen (hospital protocol group), and 98 received an alternative decolonization regimen (other treatment group). No attempt at decolonization was made for 54 patients (no treatment group). The hospital protocol group demonstrated superior overall successful decolonization compared with the other treatment group (67 of 84 [80%] versus 48 of 89 [54%]; OR 3.3; 95% CI 1.6 to 7.1; P=0.0004) and the no treatment group (four of 43 [9%]; OR 36.9; 95% CI 11.2 to 161.7; P<0.000001). The mean observed duration of culture negativity for the subgroup who remained MRSA culture negative over the long term was 419±398 days (range one to 1817 days). Successful decolonization occurred in 115 patients and permitted subsequent release from contact isolation for 4530 patient-days. The rate of clinical infection with MRSA was significantly lower in the hospital protocol group versus the other treatment group (16 of 89 [18%] versus 37 of 98 [38%]; OR 0.38; 95% CI 0.18 to 0.78; P=0.003).

CONCLUSION

The present study supports recent reports indicating that MRSA decolonization can be successful using a multifactorial approach (chlorhexidine soap, enhanced hygiene/housekeeping and combination oral/topical antimicrobial therapy) in hospitalized patients, both over the short and long term. Unlike previous studies, decolonization appeared to be effective in a relatively unselected population, including patients with lines and catheters. Inability to decolonize was most closely associated with failure to use a standardized decolonization protocol.

The management of infection and colonization due to methicillin-resistant Staphylococcus aureus: A CIDS/CAMM position paper

Methicillin-resistant Staphylococcus aureus (MRSA) is being seen with greater frequency in most hospitals and other health care facilities across Canada. The organism may cause life-threatening infections and has been associated with institutional outbreaks. Several studies have confirmed that MRSA infection is associated with increased morbidity and mortality compared with infections caused by susceptible strains, even when the presence of comorbidities is accounted for. Treatment of MRSA infection is complicated by the fact that these organisms are resistant to multiple antimicrobial agents, so treatment options are limited. The effectiveness of decolonization therapy (attempting to eradicate MRSA carriage) is also uncertain. This paper reviews the medical management of MRSA infections, discusses the potential role of decolonization and provides an overview of evidence to support recommended infection control practices.

Successful treatment for carriage of methicillin-resistant Staphylococcus aureus and importance of follow-up

With this prospective observational follow-up study of 165 methicillin-resistant Staphylococcus aureus (MRSA)-positive individuals (23 health care workers and 142 patients), we determined that our MRSA eradication therapy protocol results in a high success rate (81%). Five or more negative culture sets give a predictive value for MRSA eradication therapy success of >90%. Furthermore, MRSA colonization, at least in the throat, and the presence of wounds just before the start of MRSA eradication therapy are associated with MRSA eradication therapy failure.

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.

The role of healthcare personnel in the maintenance and spread of methicillin-resistant Staphylococcus aureus

Healthcare workers may acquire methicillin-resistant Staphylococcus aureus (MRSA) from patients, both hospital and home environments, other healthcare workers, family and public acquaintances, and pets. There is a consensus of case reports and series which now strongly support the role for MRSA-carrying healthcare personnel to serve as a reservoir and as a vehicle of spread within healthcare settings. Carriage may occur at a number of body sites and for short, intermediate, and long terms. A number of approaches have been taken to interrupt the linkage of staff-patient spread, but most emphasis has been placed on handwashing and the treatment of staff MRSA carriers. The importance of healthcare workers in transmission has been viewed with varying degrees of interest, and several logistical problems have arisen when healthcare worker screening is brought to the forefront. There is now considerable support for the screening and treatment of healthcare workers, but it is suggested that the intensity of any such approach must consider available resources, the nature of the outbreak, and the strength of epidemiological associations. The task of assessing healthcare personnel carriage in any context should be shaped with due regard to national and international guidelines, should be honed and practiced according to local needs and experience, and must be patient-oriented.

Intestinal carriage of Staphylococcus aureus: how does its frequency compare with that of nasal carriage and what is its clinical impact?

The bacterial species Staphylococcus aureus, including its methicillin-resistant variant (MRSA), finds its primary ecological niche in the human nose, but is also able to colonize the intestines and the perineal region. Intestinal carriage has not been widely investigated despite its potential clinical impact. This review summarizes literature on the topic and sketches the current state of affairs from a microbiological and infectious diseases' perspective. Major findings are that the average reported detection rate of intestinal carriage in healthy individuals and patients is 20% for S. aureus and 9% for MRSA, which is approximately half of that for nasal carriage. Nasal carriage seems to predispose to intestinal carriage, but sole intestinal carriage occurs relatively frequently and is observed in 1 out of 3 intestinal carriers, which provides a rationale to include intestinal screening for surveillance or in outbreak settings. Colonization of the intestinal tract with S. aureus at a young age occurs at a high frequency and may affect the host's immune system. The frequency of intestinal carriage is generally underestimated and may significantly contribute to bacterial dissemination and subsequent risk of infections. Whether intestinal rather than nasal S. aureus carriage is a primary predictor for infections is still ill-defined.

Health-care workers: source, vector, or victim of MRSA?

There is ongoing controversy about the role of health-care workers in transmission of meticillin-resistant Staphylococcus aureus (MRSA). We did a search of the literature from January, 1980, to March, 2006, to determine the likelihood of MRSA colonisation and infection in health-care workers and to assess their role in MRSA transmission. In 127 investigations, the average MRSA carriage rate among 33 318 screened health-care workers was 4.6%; 5.1% had clinical infections. Risk factors included chronic skin diseases, poor hygiene practices, and having worked in countries with endemic MRSA. Both transiently and persistently colonised health-care workers were responsible for several MRSA clusters. Transmission from personnel to patients was likely in 63 (93%) of 68 studies that undertook genotyping. MRSA eradication was achieved in 449 (88%) of 510 health-care workers. Subclinical infections and colonisation of extranasal sites were associated with persistent carriage. We discuss advantages and disadvantages of screening and eradication policies for MRSA control and give recommendations for the management of colonised health-care workers in different settings.

Oral rifampin for eradication of Staphylococcus aureus carriage from healthy and sick populations: a systematic review of the evidence from comparative trials

BACKGROUND

Rifampin has been used for the eradication of Staphylococcus aureus (S. aureus) colonization in various populations of healthy and sick people.

METHODS

We performed a systematic review of the evidence from randomized and nonrandomized controlled trials that compared the effectiveness and safety of a rifampin-based regimen with another regimen in eradicating S. aureus colonization from healthy and sick people.

RESULTS

Nine comparative trials (6 of which were randomized controlled trials) were included in our analysis. S. aureus was eradicated more commonly in patients receiving rifampin-containing regimens compared to monotherapy with other systemic agents (ciprofloxacin, cloxacillin, minocycline, or vancomycin), both during early and late (>1 month after therapy) post treatment evaluations (odds ratio [OR] 46.2, 95% confidence interval [CI] 14.4-148, and OR 8.8, 95% CI 3.4-22.5 respectively, 4 studies included). There was no statistically significant difference between rifampin monotherapy and combinations of rifampin with other topical (bacitracin) or systemic (cloxacillin and minocycline) antibiotics in eradicating S. aureus both in early and late evaluations (OR 1.5, 95% CI 0.5-4.4, and OR 1.6, 95% CI 0.7-3.7, respectively, 3 studies included). Eradication of methicillin-resistant S. aureus (MRSA) varied according to the type and duration of the rifampin-containing regimen. It ranged from 25% for the combination of rifampin with trimethoprim/sulfamethoxazole for 5 days to 100% for the combination of oral rifampin and minocycline for 14 days. Discontinuation of rifampin due to drug-related toxicity was necessary in 2% of 282 studied patients. Development of resistance of S. aureus to rifampin during and after treatment with a regimen containing rifampin ranged from 0% to 40% (7 studies) and overall 17% of the 236 patients for whom relevant data was reported.

CONCLUSION

The available evidence suggests that oral rifampin is an effective agent for the eradication of S. aureus carriage. However, development of antimicrobial resistance during and after treatment with rifampin occurs in a considerable proportion of patients; using rifampin in combination with another antimicrobial agent may decrease this resistance.

Randomized Controlled Trial of Chlorhexidine Gluconate for Washing, Intranasal Mupirocin, and Rifampin and Doxycycline Versus No Treatment for the Eradication of Methicillin-Resistant Staphylococcus aureus Colonization

BACKGROUND

Eradication of methicillin-resistant Staphylococcus aureus (MRSA) carriage may reduce the risk of MRSA infection and prevent transmission of the organism to other patients.

METHODS

To determine the efficacy of decolonization therapy, patients colonized with MRSA were randomized (3:1 allocation) to receive treatment (2% chlorhexidine gluconate washes and 2% mupirocin ointment intranasally, with oral rifampin and doxycycline for 7 days), or no treatment. Follow-up samples for MRSA culture were obtained from the nares, perineum, skin lesions, and catheter exit sites monthly for up to 8 months. The primary outcome measure was detection of MRSA at 3 months of follow-up. Univariate and multivariable analyses were performed to identify variables associated with treatment failure.

RESULTS

Of 146 patients enrolled in the study, 112 patients (87 treated; 25 not treated) were followed up for at least 3 months. At 3 months of follow-up, 64 (74%) of those treated had culture results negative for MRSA, compared with 8 (32%) of those not treated (P=.0001). This difference remained significant at 8 months of follow-up, at which time, 54% of those treated had culture results negative for MRSA (chi2=64.4; P<.0001, by log-rank test). The results of the multivariable analysis indicated that having a mupirocin-resistant isolate at baseline was associated with treatment failure (relative risk, 9.4; 95% confidence interval, 2.8-31.9; P=.0003), whereas decolonization therapy was protective (relative risk, 0.1; 95% confidence interval, 0.04-0.4; P=.0002). Mupirocin resistance emerged in only 5% of follow-up isolates.

CONCLUSIONS

Treatment with topical mupirocin, chlorhexidine gluconate washes, oral rifampin, and doxycycline for 7 days was safe and effective in eradicating MRSA colonization in hospitalized patients for at least 3 months.

Therapies and vaccines for emerging bacterial infections: learning from methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging bacterial infection worldwide, and community-acquired MRSA (CA-MRSA) infection, which has increased dramatically in frequency in many areas, is of particular clinical and public health concern. CA-MRSA outbreaks and severe infections have been reported more frequently in children, often manifesting in one of two distinct clinical syndromes, furunculosis or necrotizing pneumonia. This article outlines the molecular biology of MRSA, how molecular biology has contributed to the understanding of MRSA infections, current therapy and prevention of MRSA, and the prospects for a vaccine against S aureus.

Guidelines for the prophylaxis and treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in the UK

These evidence-based guidelines have been produced after a literature review of the treatment and prophylaxis of methicillin-resistant Staphylococcus aureus (MRSA) infection. The guidelines were further informed by antibiotic susceptibility data on MRSA from the UK. Recommendations are given for the treatment of common infections caused by MRSA, elimination of MRSA from carriage sites and prophylaxis of surgical site infection. There are several antibiotics currently available that are suitable for use in the management of this problem and potentially useful new agents are continuing to emerge.

A guide to antibiotic resistance in bacterial skin infections

The emergence of bacterial resistance to commonly used antibiotics is not new. In this review we have tried to cover the ever increasing problems facing the treatment and containment of bacterial skin infections. We have tried to give an overview of the varied mechanisms by which bacteria gain and spread antimicrobial resistance, whilst dealing with the patterns of resistance exhibited by some of the commonly encountered organisms. Where there is evidence, we have formulated an approach on how to tackle antibiotic resistance. Where there is a lack of evidence we have formulated what we perceive to be appropriate guidelines.

Penile prosthesis coating and the reduction of postoperative infection

Despite the recent development of effective oral agents for the treatment of erectile dysfunction, penile prosthesis implantation remains an effective and acceptable treatment for the significant number of men who fail to respond to nonsurgical therapy. The most serious complication that can affect the use of most prosthetic devices is infection. In penile prostheses, this can be devastating and frequently results in removal of the device despite aggressive antibiotic therapy. In recent years, new strategies have been developed in an attempt to minimize this risk. This review focuses on one such method, namely the use of an antibiotic coating on the device. It reviews recent published data regarding the effectiveness of such devices at decreasing infection rates.

Antimicrobial drugs for treating methicillin-resistant Staphylococcus aureus colonization

BACKGROUND

Eradication strategies for methicillin-resistant Staphylococcus aureus (MRSA) are variable. We sought to summarize the evidence for use of antimicrobial agents to eradicate MRSA.

OBJECTIVES

To describe the effects of topical and systemic antimicrobial agents on nasal and extra-nasal MRSA carriage, adverse events, and incidence of subsequent MRSA infections.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group's trials register (August 2003), the Cochrane Central Register of Controlled Trials (Issue 3, 2003), MEDLINE (1966 to 2003), EMBASE (1988 to 2003), handsearched relevant literature, and contacted MRSA experts and the manufacturer of mupirocin.

SELECTION CRITERIA

Randomized controlled trials of patients colonized with MRSA comparing topical or systemic antimicrobials to placebo or no treatment, and trials comparing various combinations of topical or systemic agents to no treatment, placebo, or to topical or systemic agents.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied inclusion criteria to potentially relevant trials, assessed trial methodological quality, and extracted data. Primary outcomes included eradication of MRSA, infection due to MRSA, and adverse events.

MAIN RESULTS

Six trials (384 participants) met the inclusion criteria. No difference in MRSA eradication was detected in four studies: one that compared mupirocin to placebo, two that compared one systemic agent to no treatment (fusidic acid in one and rifampin or minocycline in the other) and one that compared mupirocin to topical fusidic acid and oral trimethoprim-sulfamethoxazole, examining nasal MRSA eradication as an outcome. One study compared minocycline to rifampin, with rifampicin being more effective in relation to eradication of MRSA from all sites at day 30 (relative risk 0.16; 95% confidence intervals 0.02 to 1.00), but the difference at 90 days was not statistically significant (n = 18). Two studies (one testing novobiocin and rifampin, the other ciprofloxacin and rifampin, versus trimethoprim-sulfamethoxazole and rifampin) did not demonstrate a difference in eradication of MRSA at all sites (n = 94). Adverse events with systemic agents occurred in up to 20% of participants, however reporting was sporadic and denominators small. All trials reported development of resistance to antimicrobial agents used.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to support use of topical or systemic antimicrobial therapy for eradicating nasal or extra-nasal MRSA. There is no demonstrated superiority of either topical or systemic therapy, or of combinations of these agents. Potentially serious adverse events and development of antimicrobial resistance can result from therapy.

Decolonization of methicillin-resistant Staphylococcus aureus using oral vancomycin and topical mupirocin

The objective of this study was to assess the efficacy and safety of a short course of oral vancomycin and intranasal mupirocin ointment in the eradication of methicillin-resistant Staphylococcus aureus (MRSA) colonization. During an outbreak of MRSA, the colonized subjects received oral vancomycin and topical mupirocin. They were screened for MRSA 1, 3, 6 and 12 months after decolonization. A questionnaire was developed to evaluate the side-effects of oral vancomycin. Thirty-five subjects were treated. Clearance was achieved in all cases, in 24 (69%) subjects after one course of therapy. Twenty-eight (80%) subjects experienced some side-effects, including six (17%) who did not tolerate oral vancomycin. Although oral vancomycin, in combination with topical mupirocin, is effective in the elimination of MRSA colonization, there is a need for further studies to confirm our results and to evaluate the safety of oral vancomycin.

Role of infection control measures in limiting morbidity associated with multi-resistant organisms in critically ill patients

A retrospective comparative study was performed to determine the impact of infection control measures (ICMs) on colonization and infections due to methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae (producing transferable extended-spectrum beta-lactamase, KPESBL), and multi-resistant Enterobacter aerogenes (MREA) in intensive care unit patients. Infection Control Measures included surveillance cultures, isolation procedures and mupirocin for MRSA nasal carriage. The numbers of patients infected and/or colonized by MRSA, KPESBL or MREA were compared during two consecutive one-year periods (Period 1 before ICMs, and Period 2 after ICMs). The antibiotic consumption during the two periods was analysed. In Period 1 and Period 2, respectively, the rate of patients infected or colonized by at least one of the three organisms was 15% and 6.8% (P=0.001); by MRSA 7.7% and 2.6% (P=0. 004); by KPESBL 1.7% and 0% (P=0.25); and by MREA 5.6% and 4.3% (P=0. 47). During Period 2, there was a clear-cut decrease in the percentage of patients infected by MRSA (P=0.018), a non-significant decrease in those infected by KPESBL (P=0.06), and no decrease in patients infected by MREA (P=0.22). When calculated per 1000 patient-days, for Period 1 and Period 2, respectively, the rate of patients infected or colonized by at least one of the three organisms was 11.9 and 8.8; for MRSA it was 4 and 2.2; for KPESBL it was 1 and 0; and for MREA it was 4 and 4. Antibiotic cost was pound98.7 in Period 1 and pound62.7 in Period 2. ICMs contributed to the control of infections and colonizations due to MRSA and KPESBL but not those due to MREA.

Epidemiology of nosocomial infection and resistant organisms in patients admitted for the first time to an acute rehabilitation unit

The objectives of this study were to define the epidemiology of nosocomial bacterial colonization and infection and to define predictors of nosocomial infection among a cohort (n=423) of admissions to an acute rehabilitation unit. Overall, methicillin-resistant Staphylococcus aureus (MRSA) and enterococci were the most commonly identified colonizing organisms. Escherichia coli and Pseudomonas aeruginosa were the most commonly identified colonizing gram-negative bacilli. During 70 (16.5%) of the 423 hospitalizations in the unit, 94 nosocomial infections occurred. The most common infections were those of the urinary tract (30% of 94 infections) or a surgical site (17%), Clostridium difficile diarrhea (15%), and bloodstream infection (12.8%). Antibiotic-resistant bacteria most commonly caused bloodstream infection (41.7%) and surgical site infection (56.3%). Independent predictors of nosocomial infection at the time of admission were functional status (measured with the functional independence measure), APACHE III score, and spinal cord injury. In conclusion, gram-positive organisms were the predominant strains causing nosocomial colonization and infection. The logistic model, if verified, may be useful in defining patients who should be targeted for measures to prevent nosocomial infection.

New approaches to reduce Staphylococcus aureus nosocomial infection rates: treating S. aureus nasal carriage

BACKGROUND

Nosocomial infections cause significant patient morbidity and mortality. The 2.5 million nosocomial infections that occur each year cost the US healthcare system $5 million to $10 million. Staphylococcus aureus has long been recognized as an important pathogen in human disease and is the most common cause of nosocomial infections.

OBJECTIVE

To describe the epidemiology of S. aureus nosocomial infections that are attributable to patients' endogenous colonization.

DATA SOURCES

Review of the English-language literature and a MEDLINE search (as of September 1997).

DATA SYNTHESIS

The ecologic niche of S. aureus is the anterior nares. The prevalence of S. aureus nasal carriage is approximately 20-25%, but varies among different populations, and is influenced by age, underlying illness, race, certain behaviors, and the environment in which the person lives or works. The link between S. aureus nasal carriage and development of subsequent S. aureus infections has been established in patients on hemodialysis, on continuous ambulatory peritoneal dialysis, and those undergoing surgery. S. aureus nasal carriers have a two-to tenfold increased risk of developing S. aureus surgical site or intravenous catheter infections. Thirty percent of 100% of S. aureus infections are due to endogenous flora and infecting strains were genetically identical to nasal strains. Three treatment strategies may eliminate nasal carriage: locally applied antibiotics or disinfectants, systemic antibiotics, and bacterial interference. Among these strategies, locally applied or systemic antibiotics are most commonly used. Nasal ointments or sprays and oral antibiotics have variable efficacy and their use frequently results in antimicrobial resistance among S. aureus strains. Of the commonly used agents, mupirocin (pseudomonic acid) ointment has been shown to be 97% effective in reducing S. aureus nasal carriage. However, resistance occurs when the ointment has been applied for a prolonged period over large surface areas.

CONCLUSIONS

Given the importance of S. aureus nosocomial infections and the increased risk of S. aureus nasal carriage in patients with nosocomial infections, investigators need to study cost-effective strategies to prevent certain types of nosocomial infections or nosocomial infections that occur in specific settings. One potential strategy is to decrease S. aureus nasal carriage among certain patient populations.

Colonization byStaphylococcus AureusResistant to Methicillin and Ciprofloxacin During 20 Months' Surveillance in a Private Skilled Nursing Facility

Objective:

To evaluate endemic colonization withStaphylococcus aureusresistant to methicillin, ciprofloxacin, or both among patients of a private skilled nursing facility, with regard to colonization rate and site, and relation to infection and prior antibiotic use.

Design:

Prospective quarterly culture surveillance of nares and rectal specimens over 20 months' observation.

Results:

The mean prevalence was 3.8% in new admissions and 5.4% for in-house patients; cumulatively, 7.5% of the patients were colonized during the study period. The colonization rate remained stable during the study period. Screening of rectal, as well as nares, specimens detected substantially more colonized patients than would have been detected by nasal cultures alone. Five to seven percent of the colonized patients developed later infection with methicillin-ciprofloxacin-resistantS aureus. Colonized patients did not differ significantly from the noncolonized group in prior use of quinolones, but the colonized group was exposed significantly more frequently to other antibiotics than the noncolonized group. Eighty-three percent of methicillin-resistantS aureus(MRSA) isolated from infections and 89% from colonization were also ciprofloxacin resistant.

Conclusion:

Although all infecting and most colonizing isolates of MRSA were resistant to quinolones, the overall rate of colonization remained low and stable despite the continued use of quinolones. The findings suggest that good infection control practice has prevented broader spread of such strains in this facility.

Methicillin-resistant Staphylococcus aureus: a four-year experience in a spinal cord injury unit in Spain

Methicillin-Resistant Staphylococcus aureus (MRSA) infection poses a problem for both acute and long-term-care facilities, Spinal Cord Injury units included. This paper describes the 4-year evolution of MRSA outbreaks in a SCI unit in a university hospital where control measures were implemented from the first case detected. The protocol procedure was as follows: contact isolation, washing with antiseptic soap both those infected and those sharing the same room, contacts study and monitoring of MRSA patients up to the time when three consecutive negative cultures (sampled at time lapses of over 48 h) were obtained, antiseptic soap for the health-care personnel to wash their hands, and cultures of the nares done on the personnel in the event of an outbreak. Twenty-one (3.4%) MRSA positive cases were detected out of 550 admissions registered during the study period (November 1990 through October 1994). The evolution occurred in three outbreaks and six isolated MRSA positive patients without secondary cases. 71.5% of the cases were nosocomial. Seven (33%) were colonizated and 14 (67%) infected. The 14 patients infected presented 15 infections: nine with urinary tract infections, three surgical wound infections, two tracheostomy wound infections, and one patient with a decubitus ulcer infection. Two of those with urinary tract infections presented with secondary sepsis. No carriers were detected amongst the personnel. Urinary tract colonizations responded to treatment with cotrimoxazol except in two cases in which combined treatment was required (cotrimoxazol plus rifampicin). The patients with a MRSA positive tracheal aspirate were negative after combined treatment. Wounds and cultures of the nares responded favorably to initial treatment. One of the patients with a urinary tract infection and sepsis died the infection being a contributing cause. The prospective follow-up of the patients with MRSA positive cultures and the precocious implementation of isolation measures allow for the limitation of transmission, even although complete eradication is not possible.

Antibiotics and prevention of microbial colonization of catheters

Slime-producing staphylococci frequently colonize catheters, and when they are embedded in biofilm, they become resistant to various antibiotics. In the study that is described, the comparative efficacies of vancomycin, clindamycin, novobiocin, and minocycline, alone or in combination with rifampin, were tested in an in vitro model of colonization. The model consisted of the modified Robbins device with antibiotic-impregnated cement filling the lumen of catheter segments. The synergistic combination of minocycline and rifampin was the most efficacious in preventing bacterial colonization of slime-producing strains of Staphylococcus epidermidis and Staphylococcus aureus to catheter surfaces. A similar trend was observed when the inhibitory activities of polyurethane catheters coated with minocycline and rifampin were compared with the inhibitory activities of catheters coated with other antimicrobial agents. The inhibitory activities of catheters coated with minocycline and rifampin against S. epidermidis, S. aureus, and Enterococcus faecalis strains, for example, were significantly better than those of catheters coated with vancomycin (P < 0.05). The inhibitory activities of catheters coated with minocycline and rifampin against gram-negative bacilli and Candida albicans were comparable to those of catheters coated with ceftazidime and amphotericin B, respectively. We found that the combination of minocycline and rifampin is unique and highly effective in preventing the colonization of catheters with slime-producing staphylococci and that it also displays a broad-spectrum inhibitory activity against gram-negative bacteria and yeast cells.

Antibiotic penetration of and bactericidal activity within endothelial cells

It has been observed that the number of cases of infective endocarditis arising in patients who have no previous identifiable cardiac abnormalities is increasing, suggesting that direct bacterial interactions with endothelium may occur. Furthermore, the prolonged natural history of endocarditis, need for lengthy therapy, and frequency of relapse suggest that intracellular bacteria that may be protected from antimicrobial action and host responses exist. Using high-performance liquid chromatography, we investigated the penetration of seven antibiotics used to treat Staphylococcus aureus infections into cultured human umbilical vein endothelial cells and the effect of these antibiotics on the intracellular killing of two strains of the organism. In general, endothelial cell penetration of lipophilic drugs, such as minocycline, ciprofloxacin, and rifampin, exceeded that of hydrophilic drugs, represented by nafcillin, cefazolin, cefuroxime, and vancomycin. Bacterial killing paralleled the intracellular penetration of all the antibiotics except rifampin, which concentrated well inside cells but had poor killing activity. However, when combined with the other antibiotics, rifampin potentiated their killing activity against intracellular S. aureus.

In vitro and in vivo antibacterial activities of the glycylcyclines, a new class of semisynthetic tetracyclines

N,N-Dimethylglycylamido (DMG) derivatives of minocycline and 6-demethyl-6-deoxytetracycline are new semisynthetic tetracyclines referred to as the glycylcyclines. The in vitro activities of the glycylcyclines were evaluated in comparison with those of minocycline and tetracycline against strains carrying characterized tetracycline resistance determinants and against 995 recent clinical isolates obtained from geographically distinct medical centers in North America. The glycylcyclines were active against tetracycline-resistant strains carrying efflux [tet(A), tet(B), tet(C), and tet(D) in Escherichia coli and tet(K) in Staphylococcus aureus] and ribosomal protection [tet(M) in S. aureus, Enterococcus faecalis, and E. coli)] resistance determinants. Potent activity (MIC for 90% of strains, < or = 0.5 microgram/ml) was obtained with the glycylcyclines against methicillin-susceptible and methicillin-resistant S. aureus, E. faecalis, Enterococcus faecium, and various streptococcal species. The glycylcyclines exhibited good activity against a wide diversity of gram-negative aerobic and anaerobic bacteria, most of which were less susceptible to minocycline and tetracycline. The activities of the glycylcyclines against most organisms tested were comparable to each other. The in vivo efficacies of the glycylcyclines against acute lethal infections in mice when dosed intravenously were reflective of their in vitro activities. The glycylcyclines had efficacies comparable to that of minocycline against infections with methicillin-susceptible and methicillin-resistant S. aureus strains, a strain carrying tet(K), and a tetracycline-susceptible E. coli strain but exceeded the effectiveness of minocycline against infections with resistant isolates, including strains harboring tet(M) or tet(B). Levels of DMG-6-deoxytetracycline in serum were higher and more sustained than those of DMG-minocycline or minocycline. Our results show that the glycylcyclines have potent in vitro activities against a wide spectrum of gram-positive and gram-negative, aerobic and anaerobic bacteria, including many resistant strains. On the basis of their in vitro and in vivo activities, the glycylcyclines represent a significant advance to the tetracycline class of antibiotics and have good potential value for clinical efficacy.

Potent in vitro bactericidal activity of polymyxin B against methicillin-resistant Staphylococcus aureus (MRSA)

Eradication of methicillin-resistant Staphylococcus aureus (MRSA) carried by inpatients or healthy hospital personnel by topical use of antibiotics is an important step for preventing outbreak of MRSA nosocomial infection. In the screening of the antibiotic best suited for this purpose, we have found that polymyxin B, a commonly used antibiotic for gram-negative infection, had an unexpected strong cytokilling activity towards MRSA clinical strains, which was more potent than that of vancomycin or gentamicin. The data suggested that polymyxin B could be an antibiotic of choice in the treatment of topical carriage of or infection caused by MRSA.

In vitro activity of recombinant lysostaphin-antibiotic combinations toward methicillin-resistant Staphylococcus aureus

In vitro bactericidal experiments were performed with combinations of recombinant lysostaphin and various antibiotics against five strains of Staphylococcus aureus, including clinical isolates of methicillin-resistant S. aureus (MRSA). Sublethal concentrations of lysostaphin combined with beta-lactam antibiotics (including benzylpenicillin, methicillin, and cephalosporin B), bacitracin, or polymyxin B, exhibited rapid synergistic bactericidal activity against all S. aureus strains tested. Lysostaphin activity was additive when combined with either vancomycin, gentamicin, tetracycline, or erythromycin. Synergistic combinations of recombinant lysostaphin and antibiotics might be applicable to controlling cutaneous staphylococcal infections and MRSA carriage.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization in patients with spinal cord injury

Methicillin-resistant Staphylococcus aureus (MRSA) colonization has been a problem in the Rancho Los Amigos Medical Center (RLAMC) since 1978. This study reviews the latest 2 years' use of a protocol to prevent the spread of MRSA while allowing spinal cord injured patients to continue to participate in the rehabilitation program. The protocol included management in a private room, bathing with hexachlorophene, monitoring positive sites and clearing patients after 3 weeks of negative cultures. Clusters of cases were investigated by obtaining nasal cultures from the personnel. Sixty-seven of 584 (11%) SCI patients were colonized from July 1989 to July 1991. The prevalence of MRSA colonization was significantly greater in the pressure ulcer management service (PMS) 49/184 (27%) than in the rehabilitation spinal injury service (SIS) 18/400 (5%). The body sites colonized were wounds (58/67), nares (37/67), throat (30/67), urine (27/67) and perineum (17/67). Oral therapy with combinations of sulfamethoxazole trimethoprim (SXT) or Novobiocin with rifampin together with topical antibiotics (nares and wound sites), used in nine patients with healing wounds or recent flap surgery, resulted in clearing of the colonization in all cases. Identification and treatment of carriers in the personnel and use of preadmission screening cultures for MRSA in patients with pressure ulcers resulted in reduced inpatient admission.

Attempts to eradicate methicillin-resistant Staphylococcus aureus from a long-term-care facility with the use of mupirocin ointment

PURPOSE

To assess the impact of the use of mupirocin ointment on colonization, transmission, and infection with methicillin-resistant Staphylococcus aureus (MRSA) in a long-term-care facility.

PATIENTS AND METHODS

All 321 residents of a Veterans Affairs long-term-care facility from June 1990 through June 1991 were studied for MRSA colonization and infection. MRSA-colonized patients received mupirocin ointment to nares in the first 7 months and to nares and wounds in the second 5 months. The effect of mupirocin use on MRSA colonization and infection was monitored. All S. aureus strains isolated were tested for the development of resistance to mupirocin.

RESULTS

A total of 65 patients colonized with MRSA received mupirocin ointment. Mupirocin rapidly eliminated MRSA at the sites treated in most patients by the end of 1 week. Weekly maintenance mupirocin was not adequate to prevent recurrences--40% of patients had recurrence of MRSA. Overall, MRSA colonization in the facility, which was 22.7% +/- 1% prior to the use of mupirocin, did not change when mupirocin was used in nares only (22.2% +/- 2.1%), but did decrease to 11.5% +/- 1.8% when mupirocin was used in nares and wounds. Although colonization decreased, roommate-to-roommate transmission and MRSA infection rates, low to begin with, did not change when mupirocin was used. Mupirocin-resistant MRSA strains were isolated in 10.8% of patients.

CONCLUSIONS

Mupirocin ointment is effective at decreasing colonization with MRSA. However, constant surveillance was required to identify patients colonized at admission or experiencing recurrence of MRSA during maintenance treatment. Long-term use of mupirocin selected for mupirocin-resistant MRSA strains. Mupirocin should be saved for use in outbreak situations, and not used over the long term in facilities with endemic MRSA colonization.

Methicillin-resistant Staphylococcus aureus: a consensus review of the microbiology, pathogenesis, and epidemiology with implications for prevention and management

Methicillin-resistant Staphylococcus aureus (MRSA) has become a major nosocomial pathogen in community hospitals, long-term-care facilities, and tertiary care hospitals. The basic mechanism of resistance is alteration in penicillin-binding proteins of the organism. Methods for isolation by culture and typing of the organism are reviewed. MRSA colonization precedes infection. A major reservoir is the anterior nares. MRSA is usually introduced into an institution by a colonized or infected patient or health care worker. The principal mode of transmission is via the transiently colonized hands of hospital personnel. Indications for antibiotic therapy for eradication of colonization and treatment of infection are reviewed. Infection control guidelines and discharge policy are presented in detail for acute-care hospitals, intensive care and burn units, outpatient settings, and long-term-care facilities. Recommendations for handling an outbreak, surveillance, and culturing of patients are presented based on the known epidemiology.