Traitement du portage nasal de Staphylococcus aureus par la mupirocine nasale et prévention des infections acquises en réanimation. Etude multicentrique contrôlée

Clinical Effectiveness of Mupirocin for Preventing Staphylococcus aureus Infections in Nonsurgical Settings: A Meta-analysis

A systematic literature review and meta-analysis was performed to identify effectiveness of mupirocin decolonization in prevention of Staphylococcus aureus infections, among nonsurgical settings. Of the 15 662 unique studies identified up to August 2015, 13 randomized controlled trials, 22 quasi-experimental studies, and 1 retrospective cohort study met the inclusion criteria. Studies were excluded if mupirocin was not used for decolonization, there was no control group, or the study was conducted in an outbreak setting. The crude risk ratios were pooled (cpRR) using a random-effects model. We observed substantial heterogeneity among included studies (I(2) = 80%). Mupirocin was observed to reduce the risk for S. aureus infections by 59% (cpRR, 0.41; 95% confidence interval [CI], .36-.48) and 40% (cpRR, 0.60; 95% CI, .46-.79) in both dialysis and nondialysis settings, respectively. Mupirocin decolonization was protective against S. aureus infections among both dialysis and adult intensive care patients. Future studies are needed in other settings such as long-term care and pediatrics.

Control of endemic MRSA-what is the evidence? A personal view

Although there is extensive literature on the control of MRSA, when that concerning epidemics is excluded, only a limited amount remains regarding the control of endemic MRSA. Several guidelines have been recently published recommending stringent control measures, which are often suggested based on their success in controlling MRSA outbreaks in hospitals with few MRSA or in containing MRSA cases introduced into a hospital with no MRSA. In these settings, multiple measures are usually introduced with apparently successful results. However, results may not be generalizable to other settings and we do not know the minimum effective measures required for MRSA containment. This paper aims critically to review the literature to determine whether evidence exists for the value of the infection control measures that are widely recommended in the endemic setting. Much of this literature is based on observational studies, with few randomized, controlled trials having been conducted. More well-designed studies are required before many of the principles on which we build infection control programmes can be regarded as evidence based.

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.

[The importance of detecting methicillin-resistant Staphylococcus aureus in an intensive care setting]

In recent years, the fight against nosocomial infections has constituted a major public health challenge. Measures aimed at preventing the spread of multiresistant bacteria (MRB) through carriage combine the more or less systematic detection of carriers and precautions concerning isolation. In the light of published data, elements for the evaluation of a cost-efficiency ratio for measures concerning detection and isolation in intensive care are presented. The high levels of methicillin-resistant Staphylococcus aureus (MRSA) observed in hospitals constitute the principal target. Although isolation precautions appear to be effective, the value of detecting MRSA remains a subject of debate. Such detection has several objectives: the identification of carriers, assistance in the implementation of isolation precautions, the eradication of carriage and the evaluation of strategy. These different objectives are discussed.

[Methicillin-resistant Staphylococcus aureus: factors responsible for its incidence]

INTRODUCTION

How can we explain that the proportion of methicillin-resistant Staphylococcus aureus (MRSA) varies between the European countries, ranging from < 1% in Scandinavia to > 30% in Spain, France and Italy? This paper is aimed at attempting to determine factors at the origin of the spreading of endemic MRSA strains as of the early 1980s. Those strains are characterized by their ability to develop resistance to current antibiotics and make treatment of severe and deep infections more complex.

CURRENT KNOWLEDGE AND KEY POINTS

Differences in the virulence of MRSA strains and that of susceptible strains appear unlikely. MRSA prevalence seems to be a growing problem, especially in Southern Europe where rates of resistance to other anti-staphylococcal antibiotics are high. General policies for antibiotic therapy as well as the implementation of strategies for prevention and control of MRSA might be responsible for such rates. Indeed, once MRSA is introduced into a facility without control program, this multiresistant bacteria rapidly spreads within the hospital and becomes endemic, expanding its reservoir. FUTURE PROSPECTS ET PROJECTS: Due to the introduction of new methods in microbiology and communication, infection control measures including procedures for isolation and identification of MRSA reservoirs are still feasible; however, their implementation requires human and material resources. Areas requiring improvement in the detection of MRSA outbreaks are identified in this paper, with particular emphasis on the need for national surveillance of MRSA prevalence and reappraisal of MRSA control strategies in French hospitals.

A control programme for MRSA (methicillin-resistant Staphylococcus aureus) containment in a paediatric intensive care unit: evaluation and impact on infections caused by other micro-organisms

Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly reported as a hospital-acquired pathogen in intensive care units (ICUs). The inconsistent application of hygiene measures by healthcare workers accounts largely for the epidemic dissemination of such resistant strains. The efficacy of a control programme to prevent spread of MRSA was assessed in our paediatric ICU (PICU) from April 1992 to December 1995. Patients initially had weekly MRSA cultures taken from samples of anterior nares and perineum, but from January 1994, cultures were also obtained upon admission. Immediately after notification, all MRSA carriers were isolated. Education of hospital staff was an essential component of our programme. Nosocomial infection rates were recorded retrospectively in 1992 and 1993, and prospectively in 1994 and 1995. Incidence rates between 'pre-programme' and 'programme' periods were compared. The rate of MRSA infection decreased from 5.9-0.8/1000 Patient-Days (PD), (P < 10(-7). MRSA carriage also decreased from 34-2% (P < 10(-9) and the ratio of MRSA to all S. aureus fell from 71-11% (P < 10(-4). The decrease in the global incidence of infection from 20.1-13.9/1000 PD (P = 0.002) was due only to the decrease in MRSA infection. However, between 1994 and 1995, there was a significant increase in the number of transplant patients despite a constant patient/nurse ratio. The nosocomial infection rates caused by other micro-organisms decreased among the transplant patients from 64.8-33.2/1000 transplanted PD (P = 0.009) between 1994 and 1995. At the same time, we observed a slight increase of infections in non-transplanted patients, which may have been due to the effect of increased overall workload on those patients who were supposed to have fewer nosocomial risk factors. We conclude that implementation of infection control measures directed towards limiting person-to-person spread was effective in controlling high MRSA infection rates in a PICU, but it is important to allow enough time for staff to carry out hygiene practices thoroughly.

Staphylococcus aureus nasal carriage as a marker for subsequent staphylococcal infections in intensive care unit patients

From January to December 1994, 752 consecutive patients admitted to intensive care units (ICU) for more than two days were studied prospectively for Staphylococcus aureus colonization and infection. Nasal swabs were obtained at admission and weekly during the ICU stay. At ICU admission 166 patients (22.1%) were Staphylococcus aureus nasal carriers, while 586 were free of nasal colonization. Of the 166 nasal carriers, 163 harbored methicillin-sensitive Staphylococcus aureus (MSSA) and three methicillin-resistant Staphylococcus aureus (MRSA). During the ICU stay 24 of the 586 noncolonized patients became nasal carriers (11 MSSA and 13 MRSA), and one nasal carrier initially colonized by MSSA was reconlonized by MRSA. Staphylococcal infections were documented in 51 (6.8%) of the total 752 patients. After 14 days of ICU stay, the probability of developing staphylococcal infections was significantly higher for those patients who were nasal carriers at ICU admission than for those found to be initially negative (relative risk 59.6, 95% CI 20.37-184.32; p < 0.0001). In patients with ICU-acquired nasal colonization, most infections were documented prior to or at the time of the detection of the nasal colonization; thus, in this group of patients nasal carriage showed a lower predictive value for subsequent Staphylococcus aureus infections that that described classically. Paired isolates of nasal colonizing and clinical strains were studied by pulsed-field gel electrophoresis (PFGE) and mecA polymorphism analysis in 30 patients; identity was demonstrated in all but two patients. The results suggest that, outside the setting of an outbreak of MRSA, the detection of Staphylococcus aureus nasal carriers on admission may be particularly useful in identifying those patients who are at high risk for developing staphylococcal infections during their ICU stay.

Nosocomial Staphylococcus aureus bacteremia among nasal carriers of methicillin-resistant and methicillin-susceptible strains

OBJECTIVES

To determine the relevance of nasal carriage of Staphylococcus aureus, either methicillin-sensitive (MSSA) or methicillin-resistant (MRSA), as a risk factor for the development of nosocomial S aureus bacteremia during an MRSA outbreak.

PATIENTS AND METHODS

In this prospective cohort study, 488 patients admitted to an intensive care unit (ICU) during a 1-year period were screened with nasal swabs within 48 hours of admission and weekly thereafter in order to identify nasal S aureus carriage. Nasal staphylococcal carriers were observed until development of S aureus bacteremia, ICU discharge, or death.

RESULTS

One hundred forty-seven (30.1%) of 488 patients were nasal S aureus carriers; 84 patients (17.2%) harbored methicillin-sensitive S aureus; and 63 patients (12.9%) methicillin-resistant S aureus. Nosocomial S aureus bacteremia was diagnosed in 38 (7.7%) of 488 patients. Rates of bacteremia were 24 (38%) of the MRSA carriers, eight (9.5%) of the MSSA carriers, and six (1.7%) of noncarriers. After adjusting for other predictors of bacteremia by means of a Cox proportional hazard regression model, the relative risk for S aureus bacteremia was 3.9 (95% confidence interval, 1.6-9.8; P = 0.002) for MRSA carriers compared with MSSA carriers.

CONCLUSIONS

Among ICU patients, nasal carriers of S aureus are at higher risk for S aureus bacteremia than are noncarriers; in the setting of an MRSA outbreak, colonization by methicillin-resistant strains represents a greater risk than does colonization by MSSA and strongly predicts the occurrence of MRSA bacteremia.