Eradication of Methicillin-ResistantStaphylococcus AureusFrom a Neonatal Intensive Care Unit by Active Surveillance and Aggressive Infection Control Measures

Implementation of infection prevention and control for hospitalized neonates: A narrative review

BACKGROUND

The most prevalent infections encountered in neonatal care are healthcare-associated infections. The majority of healthcare-associated infections are considered preventable with evidence-based infection prevention and control (IPC) practices. However, substantial knowledge gaps exist in IPC implementation in neonatal care. Furthermore, the knowledge of factors which facilitate or challenge the uptake and sustainment of IPC programmes in neonatal units is limited. The integration of implementation science approaches in IPC programmes in neonatal care aims to address these problems.

OBJECTIVES

The aim of this narrative review was to identify determinants which have been reported to influence the implementation of IPC programmes and best practices in inpatient neonatal care settings.

SOURCES

A literature search was conducted in PubMed, MEDLINE (Medical Literature Analysis and Retrieval System Online) and CINAHL (Cumulative Index to Nursing and Allied Health Literature) in May 2022. Primary study reports published in English, French, German, Spanish, Portuguese, Italian, Danish, Swedish or Norwegian since 2000 were eligible for inclusion. Included studies focused on IPC practices in inpatient neonatal care settings and reported determinants which influenced implementation processes.

CONTENT

The Consolidated Framework for Implementation Research was used to identify and cluster reported determinants to the implementation of IPC practices and programmes in neonatal care. Most studies reported challenges and facilitators at the organizational level as particularly relevant to implementation processes. The commonly reported determinants included staffing levels, work- and caseloads, as well as aspects of organizational culture such as communication and leadership.

IMPLICATIONS

The presented knowledge about factors influencing neonatal IPC can support the design, implementation, and evaluation of IPC practices.

Healthcare worker perceptions surrounding Staphylococcus aureus transmission and prevention practices in the neonatal intensive care unit

OBJECTIVE

To understand healthcare worker (HCW) perceptions surrounding Staphylococcus aureus transmission and prevention in the neonatal intensive care unit (NICU).

DESIGN

Qualitative case study with focus groups.

SETTING

A level IV, 150-bed NICU at a Midwestern academic medical center that conducts active surveillance and decolonization of S. aureus-positive patients.

PARTICIPANTS

NICU HCWs, including bedside nurses, nurse managers, therapy services personnel, pediatric nurse practitioners, clinical fellows, and attending neonatologists.

METHODS

Semistructured focus group interviews, assembled by occupation, were conducted by 2 study team members. Interviews were video recorded and transcribed. Deductive coding and thematic analyses were performed using NVivo software.

RESULTS

In total, 38 HCWs participated in 10 focus groups (1-12 participants each), lasting 40-90 minutes. Four main themes emerged: (1) Methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) are inconsistently described as high risk. (2) Infection prevention interventions are burdensome. (3) Multiple sources of transmission are recognized. (4) opportunities exist to advance infection prevention. HCWs perceived MSSA to be less clinically relevant than MRSA. Participants expressed a desire to see published data supporting infection prevention interventions, including contact precautions, environmental cleaning, and patient decolonization. These practices were identified to be considerable burdens. HCWs perceived families to be the main source of S. aureus in the NICU, and they suggested opportunities for families to play a larger role in infection prevention.

CONCLUSIONS

These data highlight opportunities for HCW and parental education, research, and reevaluating interventions aimed at improving infection prevention efforts to reduce the burden of S. aureus in NICU settings.

Impact of decolonization on methicillin-resistant Staphylococcus aureus transmission and infection in a neonatal intensive care unit

BACKGROUND

The value of decolonization as a strategy for preventing methicillin-resistantStaphylococcus aureus (MRSA) in the neonatal intensive care unit (NICU) remains to be determined.

OBJECTIVE

After adding decolonization to further reduce MRSA transmission in our NICU, we conducted this retrospective review to evaluate its effectiveness.

METHOD

The review included patients who were admitted to our NICU between April 2015 and June 2018 and were eligible for decolonization including twice daily intranasal mupirocin and daily chlorhexidine gluconate bathing over 5 consecutive days. Patients were considered successfully decolonized if 3 subsequent MRSA screenings conducted at 1-week intervals were negative. The MRSA acquisition rate (AR) was calculated as hospital-acquired (HA) MRSA per 1,000 patient days (PD) and was used to measure the effectiveness of the decolonization.

RESULTS

Of the 151 MRSA patients being reviewed, 78 (51.6%) were HA-MRSA, resulting in an overall AR of 1.27 per 1,000 PD. Between April 2015 and February 2016, when only the decolonization was added, the AR was 2.38 per 1,000 PD. Between March 2016 and June 2018 after unit added a technician dedicated to the cleaning of reusable equipment, the AR decreased significantly to 0.92 per 1,000 PD (P < .05). Of the 78 patients who were started on the decolonization, 49 (62.8%) completed the protocol, 11 (14.1%) remained colonized, and 13 (16.7%) were recolonized prior to NICU discharge.

CONCLUSION

In a NICU with comprehensive MRSA prevention measures in place, enhancing the cleaning of reusable equipment, not decolonization, led to significant reduction of MRSA transmission.

The Role of the Environment and Colonization in Healthcare-Associated Infections

Healthcare-associated infections (HAIs) can be caused by endogenous host microbial flora or by exogenous microbes, including those found in the hospital environment. Efforts to decrease endogenous pathogens via decolonization and skin antisepsis may decrease the risk of infection in some settings. Controlling the spread of potential pathogens from the environment requires meticulous attention to cleaning and disinfection practices. In addition to selection of the appropriate cleaning agent, use of tools that assess the adequacy of cleaning and addition of no-touch cleaning technology may decrease environmental contamination. Hand hygiene is also a critical component of preventing transmission of pathogens from the environment to patients via healthcare worker hands.

Whole-genome sequencing for methicillin-resistant Staphylococcus aureus (MRSA) outbreak investigation in a neonatal intensive care unit

OBJECTIVE

To evaluate whole-genome sequencing (WGS) as a molecular typing tool for MRSA outbreak investigation.

DESIGN

Investigation of MRSA colonization/infection in a neonatal intensive care unit (NICU) over 3 years (2014-2017).

SETTING

Single-center level IV NICU.PatientsNICU infants and healthcare workers (HCWs).

METHODS

Infants were screened for MRSA using a swab of the anterior nares, axilla, and groin, initially by targeted (ring) screening, and later by universal weekly screening. Clinical cultures were collected as indicated. HCWs were screened once using swabs of the anterior nares. MRSA isolates were typed using WGS with core-genome multilocus sequence typing (cgMLST) analysis and by pulsed-field gel electrophoresis (PFGE). Colonized and infected infants and HCWs were decolonized. Control strategies included reinforcement of hand hygiene, use of contact precautions, cohorting, enhanced environmental cleaning, and remodeling of the NICU.

RESULTS

We identified 64 MRSA-positive infants: 53 (83%) by screening and 11 (17%) by clinical cultures. Of 85 screened HCWs, 5 (6%) were MRSA positive. WGS of MRSA isolates identified 2 large clusters (WGS groups 1 and 2), 1 small cluster (WGS group 3), and 8 unrelated isolates. PFGE failed to distinguish WGS group 2 and 3 isolates. WGS groups 1 and 2 were codistributed over time. HCW MRSA isolates were primarily in WGS group 1. New infant MRSA cases declined after implementation of the control interventions.

CONCLUSION

We identified 2 contemporaneous MRSA outbreaks alongside sporadic cases in a NICU. WGS was used to determine strain relatedness at a higher resolution than PFGE and was useful in guiding efforts to control MRSA transmission.

Successful termination of sustained transmission of resident MRSA following extensive NICU refurbishment: an intervention study

BACKGROUND

Neonatal sepsis is a leading cause of morbidity and mortality in neonatal units worldwide. Meticillin-resistant Staphylococcus aureus (MRSA) has become a leading causative pathogen. Many neonatal units experience endemic colonization and infection of their infants, which is often very challenging to successfully eradicate.

AIM

To assess the impact of neonatal unit refurbishment and redesign on endemic MRSA colonization and infection.

METHODS

A retrospective review was carried out over an eight-year period in a 14-cot, level 2-3 neonatal unit in University Hospital Galway, a large university teaching hospital in the West of Ireland. Surveillance, colonization, and infection data for a four-year period pre and four-year period post neonatal unit refurbishment are described. Clinical and microbiological data were collected on all MRSA-colonized and -infected infants between 2008 and 2015. Molecular typing data are available for MRSA isolates. An interrupted time-series design was used, with unit refurbishment as the intervention.

FINDINGS

Our neonatal unit had a pattern of sustained transmission of endemic resident MRSA strains which we could not eradicate despite repeated standard infection control interventions. Complete unit refurbishment led to successful termination of sustained transmission of these strains. Colonization decreased and no infants were actively infected post refurbishment of the unit.

CONCLUSION

We report successful termination of sustained transmission of endemic strains of MRSA from our neonatal unit following complete unit redesign and refurbishment.

Efficacy of periodic surveillance culture in a neonatal intensive care unit in the presumption of causative pathogens of late-onset bacterial infection

BACKGROUND

Surveillance cultures have been recommended for infection control of resistant bacteria in neonatal intensive care units (NICUs). However, the utility of surveillance cultures in the presumption of causative bacteria in late-onset bacterial infection has been controversial. The aim of the present study was to investigate the relationship between the causative pathogens of late-onset bacterial infection and the results of periodic surveillance cultures in a NICU.

METHODS

A retrospective study was performed on 600 patients hospitalized in the NICU of a large metropolitan hospital from 2010-2013. The correspondence of the results of surveillance cultures with causative pathogens was analyzed in patients who developed late-onset bacterial infection.

RESULTS

Staphylococcus species and enterobacterium were the most prevalent in the samples obtained from the oropharynx and rectum, respectively, during the investigation period. Twenty patients (3.3%) developed late-onset bacterial infection. The causative pathogens in 15 patients (75%) were also detected from the final surveillance cultures; these patients tended to be older than the other 5 patients (P = .003).

CONCLUSIONS

Surveillance cultures might be useful for the presumption of causative pathogens of late-onset bacterial infection in patients with risk factors for the development of nosocomial bacterial infection.

Meticillin-resistant Staphylococcus aureus (MRSA) acquisition risk in an endemic neonatal intensive care unit with an active surveillance culture and decolonization programme

BACKGROUND

Meticillin-resistant Staphylococcus aureus (MRSA) is a leading cause of healthcare-associated infection in the neonatal intensive care unit (NICU). Decolonization may eliminate bacterial reservoirs that drive MRSA transmission.

AIM

To measure the association between colonization pressure from decolonized and non-decolonized neonates and MRSA acquisition to inform use of this strategy for control of endemic MRSA.

METHODS

An eight-year retrospective cohort study was conducted in a level-4 NICU that used active surveillance cultures and decolonization for MRSA control. Weekly colonization pressure exposures were defined as the number of patient-days of concurrent admission with treated (decolonized) and untreated (non-decolonized) MRSA carriers in the preceding seven days. Poisson regression was used to estimate risk of incident MRSA colonization associated with colonization pressure exposures. The population-attributable fraction was calculated to assess the proportion of overall unit MRSA incidence attributable to treated or untreated patients in this setting.

FINDINGS

Every person-day increase in exposure to an untreated MRSA carrier was associated with a 6% increase in MRSA acquisition risk [relative risk (RR): 1.06; 95% confidence interval (CI): 1.01-1.11]. Risk of acquisition was not influenced by exposure to treated, isolated MRSA carriers (RR: 1.01; 95% CI: 0.98-1.04). In the context of this MRSA control programme, 22% (95% CI: 4.0-37) of MRSA acquisition could be attributed to exposures to untreated MRSA carriers.

CONCLUSION

Untreated MRSA carriers were an important reservoir for transmission. Decolonized patients on contact isolation posed no detectable transmission threat, supporting the hypothesis that decolonization may reduce patient-to-patient transmission. Non-patient reservoirs may contribute to unit MRSA acquisition and require further investigation.

Surveillance and Isolation of Methicillin-Resistant Staphylococcus aureus Colonization in the Neonatal Intensive Care Unit

BACKGROUND

Neonatal sepsis causes 1.4 million (36%) neonatal deaths annually. Staphylococcus aureus (SA), a common skin pathogen, remains the second leading cause of late-onset sepsis in the neonatal intensive care unit (NICU). Methicillin-resistant Staphylococcus aureus (MRSA), a resistant strain of SA, has created a significant global communicable health risk, especially in the NICU.

PURPOSE

To examine evidence related to NICU infection control practices surrounding MRSA surveillance, identification, and isolation in response to the clinical question, "What strategies should be universally implemented in the NICU to identify and prevent the spread of MRSA?"

METHODS/SEARCH STRATEGY

Databases were examined for articles on the topical area of MRSA in the neonate. Key terms were used to streamline the search, resulting in 20 primary works and 3 guideline/consensus statements considered imperative in response to the clinical questions.

FINDINGS/RESULTS

Hand hygiene remains the cornerstone to sound infection control practice. Colonization often leads to systemic infection, with smaller neonates at greatest risk. Hospital infection control compliance has improved outcomes. MRSA surveillance has reduced horizontal spread. No universal, specific recommendations exist to guide surveillance and management of MRSA in the NICU.

IMPLICATIONS FOR PRACTICE

Standardized guidelines with procedures for hand hygiene, patient surveillance and isolation, and patient cohorting with recommended staffing patterns should guide practice in the NICU. Both MRSA culture and polymerase chain reaction effectively identify positive patients. Decolonization practices are not yet clear.

IMPLICATIONS FOR RESEARCH

Evaluation of standard isolation practices versus outbreak response and approaches to neonatal decolonization should be evaluated for efficacy, safety, and resistance.

What To Think If the Results of the National Institutes of Health Randomized Trial of Methicillin-ResistantStaphylococcus aureusand Vancomycin-ResistantEnterococcusControl Measures Are Negative (and Other Advice to Young Epidemiologists): A Review and an Au Revoir

The incidence of methicillin-resistantStaphylococcus aureus(MRSA) and vancomycin-resistantEnterococcus(VRE) infections continues to rise in National Nosocomial Infections Surveillance system hospitals, and these pathogens are reportedly causing more than 100,000 infections and many deaths each year in US healthcare facilities. This has led some to insist that control measures are now urgently needed, but several recent articles have suggested that isolation of patients does not work, is not needed, or is unsafe, or that a single cluster-randomized trial could be used to decide such matters. At least 101 studies have reported controlling MRSA infection and 38 have reported controlling VRE infection by means of active detection by surveillance culture and use of isolation for all colonized patients in healthcare settings where the pathogens are epidemic or endemic, in academic and nonacademic hospitals, and in acute care, intensive care, and long-term care settings. MRSA colonization and infection have been controlled to exceedingly low levels in multiple nations and in the state of Western Australia for decades by use of active detection and isolation. Studies suggesting problems with using such data to control MRSA colonization and infection have their own problems, which are discussed. Randomized trials are epidemiologic tools that can sometimes provide erroneous results, and they have not been considered necessary for studying isolation before it is used to control other important infections, such as tuberculosis, smallpox, and severe acute respiratory syndrome. No single epidemiologic study should be considered definitive. One should always weigh all available evidence. Infection with antibiotic-resistant pathogens such as MRSA and VRE is controllable to a low level by active detection and isolation of colonized and infected patients. Effective measures should be used to minimize the morbidity and mortality attributable to these largely preventable infections.

Active Surveillance Cultures and Decolonization to Reduce Staphylococcus aureus Infections in the Neonatal Intensive Care Unit

BACKGROUND

Staphylococcus aureus is a common cause of healthcare-associated infections in neonates.

OBJECTIVE

To examine the impact of methicillin-susceptible S. aureus (MSSA) decolonization on the incidence of MSSA infection and to measure the prevalence of mupirocin resistance.

METHODS

We retrospectively identified neonates admitted to a tertiary care neonatal intensive care unit (NICU) from April 1, 2011, through September 30, 2014. We compared rates of MSSA-positive cultures and infections before and after implementation of an active surveillance culture and decolonization intervention for MSSA-colonized neonates. We used 2 measurements to identify the primary outcome, NICU-attributable MSSA: (1) any culture sent during routine clinical care that grew MSSA and (2) any culture that grew MSSA and met criteria of the National Healthcare Safety Network's healthcare-associated infection surveillance definitions. S. aureus isolates were tested for mupirocin susceptibility. We estimated incidence rate ratios using interrupted time-series models.

RESULTS

Before and after the intervention, 1,523 neonates (29,220 patient-days) and 1,195 neonates (22,045 patient-days) were admitted to the NICU, respectively. There was an immediate reduction in the mean quarterly incidence rate of NICU-attributable MSSA-positive clinical cultures of 64% (incidence rate ratio, 0.36 [95% CI, 0.19-0.70]) after implementation of the intervention, and MSSA-positive culture rates continued to decrease by 21% per quarter (incidence rate ratio, 0.79 [95% CI, 0.74-0.84]). MSSA infections also decreased by 73% immediately following the intervention implementation (incidence rate ratio, 0.27 [95% CI, 0.10-0.79]). No mupirocin resistance was detected.

CONCLUSION

Active surveillance cultures and decolonization may be effective in decreasing S. aureus infections in NICUs.

Evaluation of BD Max StaphSR and BD Max MRSAXT Assays Using ESwab-Collected Specimens

The BD Max MRSAXT and the BD Max StaphSR assays were validated for the detection of methicillin-resistant Staphylococcus aureus (MRSA) in ESwab samples. In addition, the BD Max StaphSR assay was evaluated for its ability to detect and differentiate S. aureus and MRSA in the same sample. A total of 255 ESwab samples collected from the anterior nares of patients were tested by each of three BD Max assays, including the BD Max MRSA first-generation assay. The results were compared to those of direct and enrichment culture. Additionally, a challenge panel comprising 14 control strains was evaluated to determine the ability of these assays to correctly identify MRSA and also appropriately differentiate S. aureus by the BD Max StaphSR assay. Out of 255 clinical samples tested, 161 were negative and 30 were positive for MRSA, and 45 were positive for S. aureus (by BD Max StaphSR) and negative for MRSA by all three PCR assays and culture. Nineteen samples had discrepant results; all of them were retested by additional laboratory testing. All strains from the challenge panel were correctly identified or excluded by the BD Max MRSAXT and BD Max StaphSR assays. The results showed that the BD Max StaphSR and the BD MRSAXT assays have excellent sensitivity (94.3%) and specificity (97.7%) for detecting MRSA. The BD Max StaphSR assay demonstrated excellent sensitivity (96.4%) and specificity (93.6%) for detecting S. aureus.

Legislative Mandates for Use of Active Surveillance Cultures to Screen for Methicillin-ResistantStaphylococcus aureusand Vancomycin-Resistant Enterococci: Position Statement From the Joint SHEA and APIC Task Force

Legislation aimed at controlling antimicrobial-resistant pathogens through the use of active surveillance cultures to screen hospitalized patients has been introduced in at least 2 US states. In response to the proposed legislation, the Society for Healthcare Epidemiology of America (SHEA) and the Association of Professionals in Infection Control and Epidemiology (APIC) have developed this joint position statement. Both organizations are dedicated to combating healthcare-associated infections with a wide array of methods, including the use of active surveillance cultures in appropriate circumstances. This position statement reviews the proposed legislation and the rationale for use of active surveillance cultures, examines the scientific evidence supporting the use of this strategy, and discusses a number of unresolved issues surrounding legislation mandating use of active surveillance cultures. The following 5 consensus points are offered. (1) Although reducing the burden of antimicrobial-resistant pathogens, including methicillin-resistantStaphylococcus aureus(MRSA) and vancomycin-resistant enterococci (VRE), is of preeminent importance, APIC and SHEA do not support legislation to mandate use of active surveillance cultures to screen for MRSA, VRE, or other antimicrobial-resistant pathogens. (2) SHEA and APIC support the continued development, validation, and application of efficacious and cost-effective strategies for the prevention of infections caused by MRSA, VRE, and other antimicrobial-resistant and antimicrobial-susceptible pathogens. (3) APIC and SHEA welcome efforts by healthcare consumers, together with private, local, state, and federal policy makers, to focus attention on and formulate solutions for the growing problem of antimicrobial resistance and healthcare-associated infections. (4) SHEA and APIC support ongoing additional research to determine and optimize the appropriateness, utility, feasibility, and cost-effectiveness of using active surveillance cultures to screen both lower-risk and high-risk populations. (5) APIC and SHEA support stronger collaboration between state and local public health authorities and institutional infection prevention and control experts.

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

Objective.

The impact of methicillin-resistant Staphylococcus aureus (MRSA) colonization on mortality has not been well characterized. We sought to describe the impact of MRSA colonization on patients admitted to intensive care units (ICUs) in the Birmingham Veterans Affairs Medical Center (VAMC).

Methods.

We conducted a retrospective cohort study of ICU patients at the Birmingham VAMC during 2005 to evaluate the predictors of MRSA colonization and determine its effect on clinical outcomes. Surveillance cultures for MRSA were performed on admission to the ICU and weekly thereafter. Clinical findings, the incidence of MRSA infection, and mortality within 3 months after ICU admission were recorded. Predictors of mortality and S. aureus colonization were determined using multivariable models.

Results.

S. aureus colonization was present in 97 (23.3%) of 416 patients screened, of whom 67 (16.1%) were colonized with methicillin-susceptible S. aureus (MSSA) and 30 (7.2%) with MRSA. All-cause mortality at 3 months among MRSA-colonized patients was significantly greater than that among MSSA-colonized patients (46.7% vs 19.4%; P = .009). MRSA colonization was an independent predictor of death (adjusted odds ratio [OR] ,3.7 [95% confidence interval {CI}, 1.5–8.9]; P = .003) and onset of MRSA infection after hospital discharge (adjusted OR, 7.6 [95% CI, 2.48–23.2]; P < .001). Risk factors for MRSA colonization included recent antibiotic use (adjusted OR, 4.8 [95% CI, 1.9–12.2]; P = .001) and dialysis (adjusted OR, 18.9 [95% CI, 2.1–167.8]; P = .008).

Conclusions.

Among ICU patients, MRSA colonization is associated with subsequent MRSA infection and an all-cause mortality that is greater than that for MSSA colonization. Active surveillance for MRSA colonization may identify individuals at risk for these adverse outcomes. Prospective studies of outcomes in MRSA-colonized patients may better define the role of programs for active MRSA surveillance.

Active Surveillance and Decolonization of Methicillin-Resistant Staphylococcus aureus on Admission to Neonatal Intensive Care Units in Hong Kong: A Cost-Effectiveness Analysis

Objective.

To examine potential clinical outcomes and cost of active methicillin-resistant Staphylococcus aureus (MRSA) surveillance with and without decolonization in neonatal intensive care units (NICUs) from the perspective of healthcare providers in Hong Kong.

Design.

Decision analysis modeling.

Setting.

NICU.

Patients.

Hypothetical cohort of patients admitted to an NICU.

Methods.

We designed a decision tree to simulate potential outcomes of active MRSA surveillance with and without decolonization in patients admitted to an NICU. Outcome measures included total direct medical cost per patient, MRSA infection rate, and MRSA-associated mortality rate. Model inputs were derived from the literature. Sensitivity analyses evaluated the impact of uncertainty in all model variables.

Results.

In the base-case analysis, active surveillance plus decolonization showed a lower expected MRSA infection rate (0.911% vs 1.759%), MRSA-associated mortality rate (0.223% vs 0.431%), and total cost per patient (USD 47,294 vs USD 48,031) compared with active surveillance alone. Sensitivity analyses showed that active surveillance plus decolonization cost less and had lower event rates if the incidence risk ratio of acquiring MRSA infections in carriers after decolonization was less than 0.997. In 10,000 Monte Carlo simulations, active surveillance plus decolonization was significantly less costly than active surveillance alone 99.9% of the time, and both the MRSA infection rate and the MRSA-associated mortality rate were significantly lower 99.9% of the time.

Conclusions.

Active surveillance plus decolonization for patients admitted to NICUs appears to be cost saving and effective in reducing the MRSA infection rate and the MRSA-associated mortality rate if addition of decolonization to active surveillance reduces the risk of MRSA infection.

Infect Control Hosp Epidemiol 2012;33(10):1024-1030

Decolonization to prevent Staphylococcus aureus transmission and infections in the neonatal intensive care unit

Staphylococcus aureus (S. aureus) continues to be a leading cause of outbreaks and health-care-associated infections in neonatal intensive care units. In the first few months of life, many neonates acquire S. aureus as part of their delicate and evolving microbiota. Neonates that asymptomatically acquire S. aureus colonization are at increased risk of developing a subsequent S. aureus infection. This review discusses the epidemiology and prevention of S. aureus disease in neonates and how decolonization to eradicate S. aureus may decrease S. aureus transmission and infections in the neonatal intensive care unit.

Clinical, patient experience and cost impacts of performing active surveillance on known methicillin-resistant Staphylococcus aureus positive patients admitted to medical-surgical units

BACKGROUND

There is a large and growing body of evidence that methicillin-resistant Staphylococcus aureus (MRSA) screening programs are cost effective, but such screening represents a significant cost burden for hospitals. This study investigates the clinical, patient experience and cost impacts of performing active surveillance on known methicillin-resistant S aureus positive (MRSA+) patients admitted to 7 medical-surgical units of a large regional hospital, specifically to allow discontinuation of contact isolation.

METHODS

We conducted mixed-methods retrospective evaluation of a process improvement project that screened admitted patients with known MRSA+ status for continued MRSA colonization.

RESULTS

Of those eligible patients on our institution's MRSA+ list who did complete testing, 80.2% (130/162) were found to be no longer colonized, and only 19.8% (32/162) were still colonized. Forty-one percent (13/32) of interviewed patients in contact isolation for MRSA reported that isolation had affected their hospital stay, and 28% (9/32) of patients reported emotional distress resulting from their isolation. Total cost savings of the program are estimated at $101,230 per year across the 7 study units.

CONCLUSION

Our findings provide supporting evidence that a screening program targeting patients with a history of MRSA who would otherwise be placed in isolation has the potential to improve outcomes and patient experience and reduce costs.

One size does not fit all: why universal decolonization strategies to prevent methicillin-resistant Staphylococcus aureus colonization and infection in adult intensive care units may be inappropriate for neonatal intensive care units

The REDUCE MRSA Trial (Randomized Evaluation of Decolonization vs Universal Clearance to Eliminate Methicillin-Resistant Staphylococcus aureus), a large multicenter, randomized controlled trial in adult intensive care units (ICUs), found universal decolonization to be more effective than surveillance and isolation procedures with or without targeted decolonization for reducing rates of MRSA-positive clinical cultures. The Agency for Healthcare Research and Quality and the Centers for Disease Control and Prevention subsequently published protocols for implementing universal decolonization in ICUs based on the trial's methods. Caution should be exercised before widely adopting these procedures in neonatal intensive care units (NICUs), particularly strategies that involve bathing with chlorhexidine and mupirocin application due to the potential for adverse events in their unique patient population, especially preterm infants. Large multicenter trials in the NICUs are needed to evaluate the efficacy, short- and long-term safety, and cost effectiveness of these strategies prior to their widespread implementation.

Laboratory evaluation of the BD MAX MRSA assay

A comparison between the BD MAX MRSA and Xpert MRSA assays was performed using 239 nares samples. A 97.9% overall agreement between the two molecular assays was observed. The BD MAX MRSA assay proved to be a reliable alternative for a highly automated system to detect methicillin-resistant Staphylococcus aureus (MRSA) in patient nares samples.

MRSA colonization and risk of infection in the neonatal and pediatric ICU: a meta-analysis

BACKGROUND AND OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of morbidity and mortality in NICUs and PICUs. Our objective was to assess the burden of MRSA colonization on admission, study the time trends, and examine the significance of MRSA colonization in this population.

METHODS

PubMed and Embase databases were consulted. Studies that reported prevalence of MRSA colonization on ICU admission were selected. Two authors independently extracted data on MRSA colonization and infection.

RESULTS

We identified 18 suitable articles and found an overall prevalence of MRSA colonization of 1.9% (95% confidence interval [CI] 1.3%-2.6%) on admission to the NICU or PICU, with a stable trend over the past 12 years. Interestingly, 5.8% (95% CI 1.9%-11.4%) of outborn neonates were colonized with MRSA on admission to NICU, compared with just 0.2% (95% CI 0.0%-0.9%) of inborn neonates (P = .01). The pooled acquisition rate of MRSA colonization was 4.1% (95% CI 1.2%-8.6%) during the NICU and PICU stay and was as high as 6.1% (95% CI 2.8%-10.6%) when the NICU population was studied alone. There was a relative risk of 24.2 (95% CI 8.9-66.0) for colonized patients to develop a MRSA infection during hospitalization.

CONCLUSIONS

In the NICU and PICU, there are carriers of MRSA on admission, and MRSA colonization in the NICU is almost exclusively associated with outborn neonates. Importantly, despite infection control measures, the acquisition rate is high, and patients colonized with MRSA on admission are more likely to suffer a MRSA infection during hospitalization.

Management of outbreaks in neonatal intensive care units

Outbreaks in neonatal intensive care units (NICUs) have disastrous consequences for neonates and raise enormous concerns in staff, altering usual practice patterns of the NICU. Our objective was to perform a systematic analysis for gaining insights into the control and prevention of NICUs outbreaks. Epidemiology, risk factors and outcomes are reviewed.

Unrelated strain methicillin-resistant Staphylococcus aureus colonization of health care workers in a neonatal intensive care unit: findings of an outbreak investigation

Three neonates and 5 health care workers were identified as colonized with methicillin-resistant Staphylococcus aureus (MRSA) out of 222 individuals screened during an outbreak investigation in an 18-bed neonatal intensive care unit. Two of 3 MRSA neonatal isolates demonstrated identical pulsed-field gel electrophoresis clonal patterns but no clonal association was found among isolates from the 5 employees or between employees and neonates. Increased MRSA-unrelated strain colonization among health care workers supports increased MRSA community prevalence and probable decreased utility of mass screening.

Trends in invasive methicillin-resistant Staphylococcus aureus infections

OBJECTIVE

To describe trends in the incidence of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in children during 2005-2010.

METHODS

We evaluated reports of invasive MRSA infections in pediatric patients identified from population-based surveillance during 2005-2010. Cases were defined as isolation of MRSA from a normally sterile site and classified on the basis of the setting of the positive culture and presence or absence of health care exposures. Estimated annual changes in incidence were determined by using regression models. National age- and race-specific incidences for 2010 were estimated by using US census data.

RESULTS

A total of 876 pediatric cases were reported; 340 (39%) were among infants. Overall, 35% of cases were hospital-onset, 23% were health care-associated community-onset, and 42% were community-associated (CA). The incidence of invasive CA-MRSA infection per 100000 children increased from 1.1 in 2005 to 1.7 in 2010 (modeled yearly increase: 10.2%; 95% confidence interval: 2.7%-18.2%). No significant trends were observed for health care-associated community-onset and hospital-onset cases. Nationally, estimated invasive MRSA incidence in 2010 was higher among infants aged <90 days compared with older infants and children (43.9 vs 2.0 per 100000) and among black children compared with other races (6.7 vs 1.6 per 100000).

CONCLUSIONS

Invasive MRSA infection in children disproportionately affects young infants and black children. In contrast to reports of declining incidence among adults, there were no significant reductions in health care-associated MRSA infections in children. Concurrently, the incidence of CA-MRSA infections has increased, underscoring the need for defining optimal strategies to prevent MRSA infections among children with and without health care exposures.

Successful control of a Methicillin-resistant Staphylococcus aureus outbreak in a neonatal intensive care unit: a retrospective, before-after study

Background

Aim of this study was to provide a detailed description of a Methicillin-resistant Staphylococcus aureus (MRSA) outbreak management strategy in the neonatal intensive care unit of a university hospital.

Methods

This was a retrospective, “before-after” study, over two consecutive 18-month periods. The outbreak management strategy was performed by a multidisciplinary team and included: extensive healthcare workers (HCW) involvement, education, continuous hand-hygiene training and active MRSA colonization surveillance. The actions implemented were identified based on an anonymous, voluntary, reporting system, carried out among all the HCW, and regular audit and feedback were provided to the nursing staff.

The main measured outcome was the rate of MRSA infections before and after the implementation of the outbreak management strategy. Piecewise linear Poisson regression was performed and the model adjusted for confounding variables. The secondary outcome was the rate of laboratory-confirmed bloodstream infections before and after the outbreak management strategy. The rates of MRSA colonization, implementation of proposed actions, observed compliance for hand-hygiene and insertion/care of central lines were also recorded during the second period.

Results

1015 newborns were included. The rate of MRSA infections throughout the two periods fell from 3.5 to 0.7 cases per 1000 patient-days (p=0.0005). The piecewise Poisson regression analysis adjusted for confounding variables showed a significant decrease in the MRSA infection rate after the outbreak management strategy (p=0.046). A significant decrease in positive laboratory confirmed blood cultures was observed over the two periods (160 vs 83; p<0.0001). A significant decline in the MRSA colonization rate occurred over the second period (p=0.001); 93% of the proposed actions were implemented. The compliance rate for hand-hygiene and insertion/care of central lines was respectively 95.9% and 62%.

Conclusions

The implementation of multiple, simultaneous, evidence-based management strategies is effective for controlling nosocomial infections. Outbreak management strategies may benefit from tools improving the communication between the institutional and scientific leadership and the ground-level staff. These measures can help to identify individualized solutions addressing specific unit needs.

First outbreak with MRSA in a Danish neonatal intensive care unit: risk factors and control procedures

Introduction

The purpose of the study was to describe demographic and clinical characteristics and outbreak handling of a large methicillin-resistant Staphylococcus aureus (MRSA) outbreak in a neonatal intensive care unit (NICU) in Denmark June 25^th–August 8^th 2008, and to identify risk factors for MRSA transmission.

Methods

Data were collected retrospectively from medical records and the Danish Neobase database. All MRSA isolates obtained from neonates, relatives and NICU health care workers (HCW) as well as environmental cultures were typed.

Results

During the 46 day outbreak period, 102 neonates were admitted to the two neonatal wards. Ninety-nine neonates were subsequently sampled, and 32 neonates (32%) from 25 families were colonized with MRSA (spa-type t127, SCCmec V, PVL negative). Thirteen family members from 11 of those families (44%) and two of 161 HCWs (1%) were colonized with the same MRSA. No one was infected. Five environmental cultures were MRSA positive. In a multiple logistic regression analysis, nasal Continuous Positive Airway Pressure (nCPAP) treatment (p = 0.006) and Caesarean section (p = 0.016) were independent risk factors for MRSA acquisition, whereas days of exposure to MRSA was a risk factors in the unadjusted analysis (p = 0.04).

Conclusions

MRSA transmission occurs with high frequency in the NICU during hospitalization with unidentified MRSA neonates. Caesarean section and nCPAP treatment were identified as risk factors for MRSA colonization. The MRSA outbreak was controlled through infection control procedures.

MRSA transmission on a neonatal intensive care unit: epidemiological and genome-based phylogenetic analyses

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) may cause prolonged outbreaks of infections in neonatal intensive care units (NICUs). While the specific factors favouring MRSA spread on neonatal wards are not well understood, colonized infants, their relatives, or health-care workers may all be sources for MRSA transmission. Whole-genome sequencing may provide a new tool for elucidating transmission pathways of MRSA at a local scale.

METHODS AND FINDINGS

We applied whole-genome sequencing to trace MRSA spread in a NICU and performed a case-control study to identify risk factors for MRSA transmission. MRSA genomes had accumulated sequence variation sufficiently fast to reflect epidemiological linkage among individual patients, between infants and their mothers, and between infants and staff members, such that the relevance of individual nurses' nasal MRSA colonization for prolonged transmission could be evaluated. In addition to confirming previously reported risk factors, we identified an increased risk of transmission from infants with as yet unknown MRSA colonisation, in contrast to known MRSA-positive infants.

CONCLUSIONS

The integration of epidemiological (temporal, spatial) and genomic data enabled the phylogenetic testing of several hypotheses on specific MRSA transmission routes within a neonatal intensive-care unit. The pronounced risk of transmission emanating from undetected MRSA carriers suggested that increasing the frequency or speed of microbiological diagnostics could help to reduce transmission of MRSA.

Methicillin-resistant Staphylococcus aureus in the neonatal intensive care unit

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent source of infections affecting premature and critically ill infants in neonatal intensive care units (NICUs). Neonates are particularly vulnerable to colonization and infection with MRSA, and many studies have attempted to identify risk factors that predispose certain infants to its acquisition to discover potential areas for clinical intervention. In addition, epidemiologic assessment of transmission patterns and molecular analysis of changes in the characteristics of MRSA strains over time have helped clarify additional factors affecting MRSA infections in the NICU. Numerous strategies for prevention and eradication have been used with variable rates of success. Despite these interventions, MRSA remains a significant source of morbidity in the NICU population.

Infection prevention and control interventions in the first outbreak of methicillin-resistant Staphylococcus aureus infections in an equine hospital in Sweden

BACKGROUND

The first outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection in horses in Sweden occurred in 2008 at the University Animal Hospital and highlighted the need for improved infection prevention and control. The present study describes interventions and infection prevention control in an equine hospital setting July 2008 - April 2010.

METHOD

This descriptive study of interventions is based on examination of policy documents, medical records, notes from meetings and cost estimates. MRSA cases were identified through clinical sampling and telephone enquiries about horses post-surgery. Prospective sampling in the hospital environment with culture for MRSA and genotyping of isolates by spa-typing and pulsed-field gel electrophoresis (PFGE) were performed.

RESULTS

Interventions focused on interruption of indirect contact spread of MRSA between horses via staff and equipment and included: Temporary suspension of elective surgery; and identification and isolation of MRSA-infected horses; collaboration was initiated between authorities in animal and human public health, human medicine infection control and the veterinary hospital; extensive cleaning and disinfection was performed; basic hygiene and cleaning policies, staff training, equipment modification and interior renovation were implemented over seven months.Ten (11%) of 92 surfaces sampled between July 2008 and April 2010 tested positive for MRSA spa-type 011, seven of which were from the first of nine sampling occasions. PFGE typing showed the isolates to be the outbreak strain (9 of 10) or a closely related strain. Two new cases of MRSA infection occurred 14 and 19 months later, but had no proven connections to the outbreak cases.

CONCLUSIONS

Collaboration between relevant authorities and the veterinary hospital and formation of an infection control committee with an executive working group were required to move the intervention process forward. Support from hospital management and the dedication of staff were essential for the development and implementation of new, improved routines. Demonstration of the outbreak strain in the environment was useful for interventions such as improvement of cleaning routines and interior design, and increased compliance with basic hygienic precautions. The interventions led to a reduction in MRSA-positive samples and the outbreak was considered curbed as no new cases occurred for over a year.

Spread of methicillin-resistant Staphylococcus aureus in a large tertiary NICU: network analysis

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) colonization in NICUs increases the risk of nosocomial infection. Network analysis provides tools to examine the interactions among patients and staff members that put patients at risk of colonization.

METHODS

Data from MRSA surveillance cultures were combined with patient room locations, nursing assignments, and sibship information to create patient- and unit-based networks. Multivariate models were constructed to quantify the risk of incident MRSA colonization as a function of exposure to MRSA-colonized infants in these networks.

RESULTS

A MRSA-negative infant in the NICU simultaneously with a MRSA-positive infant had higher odds of becoming colonized when the colonized infant was a sibling, compared with an unrelated patient (odds ratio: 8.8 [95% confidence interval [CI]: 5.3-14.8]). Although knowing that a patient was MRSA-positive and was placed on contact precautions reduced the overall odds of another patient becoming colonized by 35% (95% CI: 20%-47%), having a nurse in common with that patient still increased the odds of colonization by 43% (95% CI: 14%-80%). Normalized group degree centrality, a unitwide network measure of connectedness between colonized and uncolonized patients, was a significant predictor of incident MRSA cases (odds ratio: 18.1 [95% CI: 3.6-90.0]).

CONCLUSIONS

Despite current infection-control strategies, patients remain at significant risk of MRSA colonization from MRSA-positive siblings and from other patients with whom they share nursing care. Strategies that minimize the frequency of staff members caring for both colonized and uncolonized infants may be beneficial in reducing the spread of MRSA colonization.

Active surveillance culturing impacts methicillin-resistant Staphylococcus aureus acquisition in a pediatric intensive care unit

OBJECTIVE

To determine whether active surveillance culturing for methicillin-resistant Staphylococcus aureus (MRSA) decreases nosocomial MRSA acquisition in the pediatric intensive care unit.

DESIGN

Before and after observational study.

SETTING

A tertiary care, 20-bed, pediatric intensive care unit.

PATIENTS

All patients admitted to the pediatric intensive care unit.

INTERVENTIONS

Anterior nares cultures for MRSA were obtained on admission and weekly in the pediatric intensive care unit from January 2007 to December 2009 as part of a hospital quality improvement project.

MEASUREMENTS AND MAIN RESULTS

MRSA admission prevalence and nosocomial incidence density were determined retrospectively for 2006 and prospectively for 2007-2009. Nosocomial MRSA incidence density during the intervention period was determined monthly and analyzed by trend analysis by using a general linear model. The correlation of active surveillance culturing compliance with nosocomial acquisition of MRSA was analyzed. Possible confounding by healthcare worker hand hygiene compliance observed during the intervention period was also analyzed by multivariate linear regression analysis. The yearly MRSA incidence density significantly decreased from 2006 to 2009 (6.88 per 1,000 patient days to 1.45 per 1,000 patient days, p < .001) and from 2007 to 2009 (7.32 per 1,000 patient days to 1.45 per 1,000 patient days, p < .001). Trend analysis demonstrated a significant decline in MRSA acquisition over time following the introduction of active surveillance culturing (p < .001). Surveillance culturing was significantly associated with the decline in MRSA acquisition observed in the pediatric intensive care unit by multivariate regression analysis when controlling for hand hygiene (p = .01).

CONCLUSIONS

Active surveillance culturing resulted in significantly decreased nosocomial acquisition of MRSA in a pediatric intensive care unit setting. Admission and weekly active surveillance culturing appears to be an effective tool to decrease the spread of MRSA in the pediatric intensive care unit, independent of improvement in hand hygiene compliance. The impact on hospital-acquired MRSA infections and the cost benefit of active surveillance culturing require further study.

A stepwise approach to control an outbreak and ongoing transmission of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit

BACKGROUND

Preventing methicillin-resistant Staphylococcus aureus (MRSA) transmission in health care facilities where MRSA is endemic is challenging yet critical.

OBJECTIVE

We sought to determine the effectiveness of 2 bundles of interventions for preventing MRSA transmission in a neonatal intensive care unit (NICU).

METHODS

This retrospective cohort study included infants admitted to our NICU between September 1, 2004, and March 31, 2009. Following a MRSA outbreak between September 2004 and September 2005, preventing ongoing MRSA transmission remained a challenge. In July 2006, bundle-I, including culture-based active surveillance, preemptive contact precaution for up to 72 hours for new admissions, and cohorting assignment of direct caregivers was introduced for eradicating MRSA transmission. Bundle-II began in April 2007 and included bundle-1 measures except that the real-time polymerase chain reaction test replaced culture for the detection of MRSA.

RESULTS

This study identified 218 infants who developed MRSA infection or colonization and 151 instances of MRSA transmission during the study period. After instituting bundle-II, the transmission rate declined from 2.9 to 2.1 per 1000 patient-days-at-risk (incidence rate ratio, 1.4; 95% confidence interval: 0.9-2.2), and hospital-acquired MRSA infections declined from 1.3 to 0.5 per 1000 patient-days-at-risk (incidence rate ratio, 2.5; 95% confidence interval: 1.1-5.8).

CONCLUSION

Despite an increasing incidence of MRSA in community settings, preventing MRSA transmission within a NICU is achievable through implementation of optimal intervention strategies.

Methicillin and Vancomycin Resistant S. aureus in Hospitalized Patients

S. aureus is the major bacterial cause of skin, soft tissue and bone infections, and one of the commonest causes of healthcare-associated bacteremia. Hospital-associated methicillin-resistant S. aureus (MRSA) carriage is associated with an increased risk of infection, morbidity and mortality. Screening of high-risk patients at the time of hospital admission and decolonization has proved to be an important factor in an effort to reduce nosocomial transmission. The electronic database Pub Med was searched for all the articles on "Establishment of MRSA and the emergence of vancomycin-resistant S. aureus (VRSA)." The search included case reports, case series and reviews. All the articles were cross-referenced to search for any more available articles. A total of 88 references were obtained. The studies showed a steady increase in the number of vancomycin-intermediate and vancomycin-resistant S. aureus. Extensive use of vancomycin creates a selective pressure that favors the outgrowth of rare, vancomycin-resistant clones leading to heterogenous vancomycin intermediate S. aureus hVISA clones, and eventually, with continued exposure, to a uniform population of vancomycin-intermediate S. aureus (VISA) clones. However, the criteria for identifying hVISA strains have not been standardized, complicating any determination of their clinical significance and role in treatment failures. The spread of MRSA from the hospital to the community, coupled with the emergence of VISA and VRSA, has become major concern among healthcare providers. Infection-control measures, reliable laboratory screening for resistance, appropriate antibiotic prescribing practices and avoidance of blanket treatment can prevent long-term emergence of resistance.

Increased use of alcohol-based hand sanitizers and successful eradication of methicillin-resistant Staphylococcus aureus from a neonatal intensive care unit: a multivariate time series analysis

BACKGROUND

We analyzed time series data to investigate factors that contributed to the gradual decrease and eventual eradication of methicillin-resistant Staphylococcus aureus (MRSA) from our neonatal intensive care unit (NICU).

METHODS

A multivariate adjusted autoregressive integrated moving average (ARIMA) model was used for time series analyses of monthly MRSA incidence density rates and their predictors in the NICU from July 2003 to July 2009.

RESULTS

Based on our ARIMA (0,1,1), which is a nonseasonal and nonstationary moving average model, the monthly pooled mean of the amount of alcohol-based hand sanitizer used for 1 patient per day (lag time, 0 month; P = .011) was the only factor significantly associated with the MRSA incidence density rates. MRSA colonization pressure, patient-to-nurse ratios, and bed occupancy rates were not associated with MRSA acquisition in the NICU. Active surveillance, which had been practiced since the late 1980s, alone was not sufficient to control the spread of MRSA until it was accompanied by enhanced hand hygiene.

CONCLUSION

Increasing the use of alcohol-based hand sanitizers by improving accessibility and providing periodic hand hygiene training sessions to health care workers is strongly recommended for decreasing the risk of MRSA acquisition among neonates in NICU settings.

The potential economic value of a Staphylococcus aureus vaccine for neonates

The continuing morbidity and mortality associated with Staphylococcus aureus (S. aureus) infections, especially methicillin-resistant S. aureus (MRSA) infections, have motivated calls to make S. aureus vaccine development a research priority. We developed a decision analytic computer simulation model to determine the potential economic impact of a S. aureus vaccine for neonates. Our results suggest that a S. aureus vaccine for the neonatal population would be strongly cost-effective (and in many situations dominant) over a wide range of vaccine efficacies (down to 10%) for vaccine costs (or=1%).

Community-associated methicillin-resistant Staphylococcus aureus strains in pediatric intensive care unit

Virulent community-associated methicillin-resistant Staphylococcus-aureus (CA-MRSA) strains have spread rapidly in the United States. To characterize the degree to which CA-MRSA strains are imported into and transmitted in pediatric intensive care units (PICU), we performed a retrospective study of children admitted to The Johns Hopkins Hospital PICU, March 1, 2007-May 31, 2008. We found that 72 (6%) of 1,674 PICU patients were colonized with MRSA. MRSA-colonized patients were more likely to be younger (median age 3 years vs. 5 years; p = 0.02) and African American (p<0.001) and to have been hospitalized within 12 months (p<0.001) than were noncolonized patients. MRSA isolates from 66 (92%) colonized patients were fingerprinted; 40 (61%) were genotypically CA-MRSA strains. CA-MRSA strains were isolated from 50% of patients who became colonized with MRSA and caused the only hospital-acquired MRSA catheter-associated bloodstream infection in the cohort. Epidemic CA-MRSA strains are becoming endemic to PICUs, can be transmitted to hospitalized children, and can cause invasive hospital-acquired infections. Further appraisal of MRSA control is needed.

Nasal colonization with methicillin-resistant Staphylococcus aureus: clinical implications and treatment

Methicillin-resistant Staphylococcus aureus (MRSA) has become an increasingly important pathogen during the past 30 years, and infections due to MRSA are associated with substantial morbidity and mortality. Despite intensive infection control measures, the prevalence of MRSA has increased significantly, and the organism has become endemic in many hospitals worldwide. Asymptomatic nasal carriage of MRSA has been identified as a major risk factor for subsequent S. aureus infection in multiple settings and populations. As a result, considerable interest exists in developing decolonization strategies, with the ultimate goal of reducing the incidence of MRSA infection. Approaches to decolonization have included the use of systemic and inhalation anti-biotics, antiseptic washes, and topical antimicrobials.

Clinical and economic impact of methicillin-resistant Staphylococcus aureus colonization or infection on neonates in intensive care units

OBJECTIVE

The rising incidence and mortality of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection in children has become a great concern. This study aimed to determine the clinical and economic impact of MRSA colonization or infection on infants and to measure excess mortality, length of stay, and hospital charges attributable to MRSA.

DESIGN

This is a retrospective cohort study.

SETTING AND PATIENTS

The study included infants admitted to a level III-IV neonatal intensive care unit from September 1, 2004, through March 31, 2008.

METHODS

A time-dependent proportional hazard model was used to analyze the association between MRSA colonization or infection and mortality. The relationships between MRSA colonization or infection and length of stay and between MRSA colonization or infection and hospital charges were assessed using a matched cohort study design.

RESULTS

Of 2,280 infants, 191 (8.4%) had MRSA colonization or infection. Of 132 MRSA isolates with antibiotic susceptibility results, 106 were resistant to clindamycin and/or trimethoprim-sulfamethoxazole, thus representing a noncommunity phenotype. The mortality rate was 17.8% for patients with MRSA colonization or infection and 11.5% for control subjects. Neither MRSA colonization (hazard ratio [HR], 0.9 [95% confidence interval {CI}, 0.5-1.5]; P > .05 ) nor infection (HR, 1.2 [95% CI, 0.7-1.9]; P > .05 ) was associated with increased mortality risk. Infection caused by MRSA strains that were resistant to clindamycin and/or trimethoprim-sulfamethoxazole increased the mortality risk by 40% (HR, 1.4 [95% CI, 0.9-2.2]; P > .05 ), compared with the mortality risk of control subjects, but the increase was not statistically significant. MRSA infection independently increased length of stay by 40 days (95% CI, 34.2-45.6; P < .001) and was associated with an extra charge of $164,301 (95% CI, $158,712-$169,889; P < .001).

CONCLUSIONS

MRSA colonization or infection in infants is associated with significant morbidity and financial burden but is not independently associated with increased mortality.

Attempted eradication of methicillin-resistant Staphylococcus aureus colonisation in horses on two farms

REASONS FOR PERFORMING STUDY

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging equine and zoonotic pathogen. Infection control protocols can be used to control MRSA in human hospitals, but measures to eradicate MRSA on horse farms have not been evaluated.

OBJECTIVES

To describe an MRSA eradication programme that was used to attempt to eliminate MRSA colonisation among horses and horse personnel on 2 equine farms.

METHODS

Active surveillance cultures and infection control protocols were implemented on 2 farms with endemic MRSA.

RESULTS

Active screening and strict implementation of infection control protocols resulted in a rapid decrease in number of colonised horses on both farms. The majority of horses eliminated MRSA without antimicrobial treatment. On one farm colonisation was eradicated, while only 2 (3%) colonised horses remained on the other farm at the end of the study.

CONCLUSIONS

Although at this stage the benefit of eradication of MRSA from populations of horses and cost-benefit studies have not been established, this study illustrates that short-term eradication can be achieved with a policy of segregation, enhanced infection control precautions and repeated testing of groups of animals.

POTENTIAL RELEVANCE

Infection control practices should form the basis of MRSA control. Antimicrobial therapy does not appear to be required for eradication of MRSA colonisation in horses and control of MRSA on farms. In appropriate circumstances, these methods may be useful for controlling the spread of this potentially serious pathogen.

An investigation of the risk factors for infection with methicillin-resistant Staphylococcus aureus among patients in a neonatal intensive care unit

BACKGROUND

The aims of this study were to investigate the risk factors of methicillin-resistant Staphylococcus aureus (MRSA) infection among infants to establish effective infection control measures for neonatal intensive care unit (NICU).

METHODS

Data were prospectively collected from 961 infants hospitalized in a teaching hospital in Japan, from July 2002 through December 2005.

RESULTS

Among all infants, 28 (2.9%) developed MRSA infections. Multivariate logistic regression analyses demonstrated the risk factors for developing MRSA infections to include a low birth weight (odds ratio [OR], 0.91; 95% confidence interval [CI]: 0.93-0.99), the presence of eye mucous (OR, 6.78; 95% CI: 2.87-16.01), the practice of kangaroo mother care (OR, 3.82; 95% CI: 1.11-13.13), and the MRSA colonization rate (OR, 11.12; 95% CI: 1.32-93.89).

CONCLUSION

The risk factors for developing a MRSA infection among infants in NICU were a low birth weight, the presence of eye mucous, the practice of kangaroo mother care, and a high MRSA colonization rate. Therefore, extra attention should be given to infants in high-risk groups demonstrating a low birth weight and the presence of eye mucous and who have undergone kangaroo mother care. As a result, the cohort isolation of infants with MRSA may therefore be an effective strategy to prevent MRSA infections.