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

Hospital-Onset Bacteremia Among Neonatal Intensive Care Unit Patients

Importance

The Centers for Disease Control and Prevention plans to introduce hospital-onset bacteremia (HOB) as a health care-associated infection measure. The epidemiology and clinical characteristics of HOB among infants admitted to the neonatal intensive care unit (NICU) are unknown.

Objective

To estimate the rate of HOB among infants admitted to the NICU, measure the association of HOB risk with birth weight group and postnatal age, and estimate HOB-attributable mortality.

Design, Setting, and Participants

This retrospective multicenter cohort study and emulated trial from 2016 to 2021 included a convenience sample of 322 NICUs in the United States. Participants were infants admitted to participating NICUs for 4 or more days.

Exposures

The primary exposures were birth weight and postnatal age. Additional exposures included small for gestational age and central line presence.

Main Outcomes and Measures

The primary study outcomes were HOB and HOB-attributable mortality.

Results

Of 451 443 included infants, 250 763 (55.6%) were male, 200 680 (44.4%) were female, and 62 091 (13.8%) were born 1500 g or less. Of 9015 HOB events that occurred among 8356 infants (2%) during 8 163 432 days at risk (unadjusted incidence rate, 1.1 per 1000 patient-days; 95% CI, 1.0-1.2), 4888 HOB events (54.2%) occurred in the absence of a central line. Within the first 2 weeks after birth, the HOB rate was 14.2 per 1000 patient-days (95% CI, 12.6-16.1) among infants born 750 g or less, to 0.4 events per 1000 patient-days among infants born more than 2500 g (95% CI, 0.4-0.5). Among infants born 750 g or less, the relative HOB risk decreased by 90% after day 42 compared with days 4 to 14 (incidence rate ratio [IRR], 0.10; 95% CI, 0.1-0.1). Conversely, among infants born more than 2500 g, the relative HOB risk increased by 50% after day 42 compared with days 4 to 14 (IRR, 1.5, 95% CI, 1.2-1.9). Compared with otherwise similar infants without HOB, infants with HOB had an absolute difference in attributable mortality of 5.5% (95% CI, 4.7-6.3).

Conclusions and Relevance

This study found that HOB events in the NICU are associated with increased mortality. Birth weight is an important risk factor for HOB; however, the relative rate of HOB decreases over postnatal age among low-birth-weight infants and increases among infants born more than 2500 g. Identifying strategies to prevent HOB and programs to decrease HOB risk are urgently needed to reduce infant mortality.

Antibiotic Stewardship in the Neonatal Intensive Care Unit

Antibiotic stewardship is a multidisciplinary, evidence-based approach to optimize antibiotic use and mitigate development of antibiotic resistance. Neonates have high rates of antibiotic exposure, particularly those born preterm and admitted to the NICU, and mounting evidence describes the adverse consequences of such exposures in the absence of infection. Here, we review the general principles of antibiotic stewardship and how they can be applied in NICUs. The unique characteristics of NICUs and patients cared for in this setting, which warrant unique implementation strategies and special considerations are discussed. We summarize current antibiotic use metrics for assessment of responses to stewardship interventions and changes over time, and review evidence-based infection prevention practices in the NICU. Current recommendations for empiric antibiotic use in the NICU and the utility of infection biomarkers are summarized. Lastly, given the growing global threat of increasing antibiotic resistance, specific threats in the NICU are highlighted.

Microbiome dysbiosis: a modifiable state and target to prevent Staphylococcus aureus infections and other diseases in neonates

Bacterial infections present a significant threat to neonates. Increasingly, studies demonstrate associations between human diseases and the microbiota, the communities of microorganisms on or in the body. A "healthy" microbiota with a great diversity and balance of microorganisms can resist harmful pathogens and protect against infections, whereas a microbiota suffering from dysbiosis, can predispose to pathogen colonization and subsequent infection. For decades, strategies such as bacterial interference, decolonization, prebiotics, and probiotics have been tested to reduce Staphylococcus aureus disease and other infections in neonates. More recently, microbiota transplant has emerged as a strategy to broadly correct dysbiosis, promote colonization resistance, and prevent infections. This paper discusses the benefits of a healthy neonate's microbiota, exposures that alter the microbiota, associations of dysbiosis and neonatal disease, strategies to prevent dysbiosis, such as microbiota transplantation, and presents a framework of microbiome manipulation to reduce Staphylococcus aureus (S. aureus) and other infections in neonates.

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.

[Update Perioperative Antibiotic Prophylaxis in Neonatology]

This narrative review discusses basic principles of the perioperative antibiotic prophylaxis (PAP) in premature and at term newborns and refers to some particularities concerning the indication and dosing issues. Although this is a vulnerable patient population, the spectrum of activity should not be unnecessarily broad and the regular PAP must not be prolonged beyond 24 hours.

Risk factors for methicillin-resistant Staphylococcus aureus colonization in a level-IV neonatal intensive care unit: a retrospective study

Objective

To identify risk factors associated with methicillin-resistant Staphylococcus aureus (MRSA) colonization in neonatal patients during an MRSA outbreak to minimize future outbreaks.

Design

Retrospective case-control study.

Setting

Level-IV neonatal intensive care unit (NICU) at Copenhagen University Hospital, Rigshospitalet, Denmark.

Patients

Neonates with either MRSA or methicillin-susceptible Staphylococcus aureus (MSSA).

Methods

Methicillin-resistant Staphylococcus aureus-positive neonates were matched with those colonized or infected with MSSA in a 1:1 ratio. The control group was selected from clinical samples, whereas MRSA-positive neonates were identified from clinical samples or from screening. A total of 140 characteristics were investigated to identify risk factors associated with MRSA acquisition. The characteristics were categorized into three categories: patient, unit, and microbiological characteristics.

Results

Out of 1,102 neonates screened for MRSA, between December 2019 and January 2022, 33 were MRSA positive. They were all colonized with an MRSA outbreak clone (spa type t127) and were included in this study. Four patients (12%) had severe infection. Admission due to respiratory diseases, need for intubation, need for peripheral venous catheters, admission to shared rooms with shared toilets and bath facilities in the aisles, and need for readmission were all correlated with later MRSA colonization (P < 0.05).

Conclusion

We identified clinically relevant diseases, procedures, and facilities that predispose patients to potentially life-threatening MRSA infections. A specific MRSA reservoir remains unidentified; however, these findings have contributed to crucial changes in our NICU to reduce the number of MRSA infections and future outbreaks.

SHEA/IDSA/APIC Practice Recommendation: Strategies to prevent methicillin-resistant Staphylococcus aureus transmission and infection in acute-care hospitals: 2022 Update

Previously published guidelines have provided comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute-care hospitals in implementing and prioritizing efforts to prevent methicillin-resistant Staphylococcus aureus (MRSA) transmission and infection. This document updates the "Strategies to Prevent Methicillin-Resistant Staphylococcus aureus Transmission and Infection in Acute Care Hospitals" published in 2014.1 This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA). It is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the Association for Professionals in Infection Control and Epidemiology (APIC), the American Hospital Association (AHA), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise.

Next Steps for Health Care-Associated Infections in the Neonatal Intensive Care Unit

We discuss the burden of health care-associated infections (HAIs) in the neonatal ICU and the role of quality improvement (QI) in infection prevention and control. We examine specific QI opportunities and approaches to prevent HAIs caused by Staphylococcus aureus , multidrug-resistant gram-negative pathogens, Candida species, and respiratory viruses, and to prevent central line-associated bloodstream infections (CLABSIs) and surgical site infections. We explore the emerging recognition that many hospital-onset bacteremia episodes are not CLABSIs. Finally, we describe the core tenets of QI, including engagement with multidisciplinary teams and families, data transparency, accountability, and the impact of larger collaborative efforts to reduce HAIs.

A tale of two intensive care units (ICUs): Baseline Staphylococcus aureus colonization and mupirocin susceptibility in neonatal and pediatric patients requiring intensive care

OBJECTIVE

To assess the incidence rate of S. aureus colonization at baseline along with the mupirocin susceptibility (or resistance) rate in patients in a neonatal intensive care unit (NICU) and a pediatric intensive care unit (PICU) in conjunction with the implementation of universal decolonization as the standard of care.

DESIGN

Prospective cohort study.

SETTING

Children's Hospital of Michigan (CHM) inpatient intensive care units (ICUs).

PARTICIPANTS

Newly admitted pediatric patients to the CHM NICU or PICU aged between 1 day and ≤21 years.

INTERVENTIONS

Baseline and follow-up S. aureus screening cultures were obtained before patients underwent universal decolonization with mupirocin 2% antibiotic ointment (intranasal and umbilical) and chlorhexidine baths as standard of care to reduce CLABSI rates.

RESULTS

Baseline S. aureus colonization rates of new admissions to the CHM NICU and PICU were high at 32% and 29%, respectively. Baseline mupirocin susceptibility to any S. aureus growth was 98.4%. All baseline culture isolates whether positive for MRSA or MSSA, with one exception, had minimum inhibitory concentrations (MICs) of ≤0.19 µg/mL. All follow-up study cultures after universal decolonization at 7 days or beyond with any S. aureus growth had mupirocin MICs of ≤0.125 µg/mL.

CONCLUSIONS

Baseline S. aureus colonization rates of new admissions to the CHM ICUs were high as was baseline mupirocin susceptibility. Follow-up cultures, albeit limited in number, did not detect increasing mupirocin MICs over 1 year, despite broad mupirocin exposure due to the implementation of universal decolonization.

Reducing MRSA Infection in a New NICU During the COVID-19 Pandemic

BACKGROUND AND OBJECTIVES

Methicillin-resistant Staphylococcus aureus (MRSA) is prevalent in most NICUs, with a high rate of skin colonization and subsequent invasive infections among hospitalized neonates. The effectiveness of interventions designed to reduce MRSA infection in the NICU during the coronavirus disease 2019 (COVID-19) pandemic has not been characterized.

METHODS

Using the Institute for Healthcare Improvement's Model for Improvement, we implemented several process-based infection prevention strategies to reduce invasive MRSA infections at our level IV NICU over 24 months. The outcome measure of invasive MRSA infections was tracked monthly utilizing control charts. Process measures focused on environmental disinfection and hospital personnel hygiene were also tracked monthly. The COVID-19 pandemic was an unexpected variable during the implementation of our project. The pandemic led to restricted visitation and heightened staff awareness of the importance of hand hygiene and proper use of personal protective equipment, as well as supply chain shortages, which may have influenced our outcome measure.

RESULTS

Invasive MRSA infections were reduced from 0.131 to 0 per 1000 patient days during the initiative. This positive shift was sustained for 30 months, along with a delayed decrease in MRSA colonization rates. Several policy and practice changes regarding personnel hygiene and environmental cleaning likely contributed to this reduction.

CONCLUSIONS

Implementation of a multidisciplinary quality improvement initiative aimed at infection prevention strategies led to a significant decrease in invasive MRSA infections in the setting of the COVID-19 pandemic.

Genomic and Epidemiological Features of Two Dominant Methicillin-Susceptible Staphylococcus aureus Clones from a Neonatal Intensive Care Unit Surveillance Effort

Methicillin-susceptible Staphylococcus aureus (MSSA) is a more prevalent neonatal intensive care unit (NICU) pathogen than methicillin-resistant S. aureus (MRSA). However, the introduction and spread of MSSA, the role of systematic decolonization, and optimal infection prevention and control strategies remain incompletely understood. We previously screened infants hospitalized in a university-affiliated level III to IV NICU twice monthly over 18 months for S. aureus colonization and identified several prevalent staphylococcal protein A (spa) types. Here, we performed whole-genome sequencing (WGS) and phylogenetic comparisons of 140 isolates from predominant spa types t279, t1451, and t571 to examine possible transmission routes and identify genomic and epidemiologic features associated with the spread of dominant clones. We identified two major MSSA clones: sequence type 398 (ST398), common in the local community, and ST1898, not previously encountered in the region. ST398 NICU isolates formed distinct clusters with closely related community isolates from previously published data sets, suggesting multiple sources of acquisition, such as family members or staff, including residents of the local community. In contrast, ST1898 isolates were nearly identical, pointing to clonal expansion within the NICU. Almost all ST1898 isolates harbored plasmids encoding mupirocin resistance (mupA), suggesting an association between the proliferation of this clone and decolonization efforts with mupirocin. Comparative genomics indicated genotype-specific pathways of introduction and spread of MSSA via community-associated (ST398) or health care-associated (ST1898) sources and the potential role of mupirocin resistance in dissemination of ST1898. Future surveillance efforts could benefit from routine genotyping to inform clone-specific infection prevention strategies. IMPORTANCE Methicillin-susceptible Staphylococcus aureus (MSSA) is a significant pathogen in neonates. However, surveillance efforts in neonatal intensive care units (NICUs) have focused primarily on methicillin-resistant S. aureus (MRSA), limiting our understanding of colonizing and infectious MSSA clones which are prevalent in the NICU. Here, we identify two dominant colonizing MSSA clones during an 18-month surveillance effort in a level III to IV NICU, ST398 and ST1898. Using genomic surveillance and phylogenetic analysis, coupled with epidemiological investigation, we found that these two sequence types had distinct modes of spread, namely the suggested exchange with community reservoirs for ST398 and the contribution of antibiotic resistance to dissemination of ST1898 in the health care setting. This study highlights the additional benefits of whole-genome surveillance for colonizing pathogens, beyond routine species identification and genotyping, to inform targeted infection prevention strategies.

Reducing Staphylococcus aureus infections in the neonatal intensive care unit

OBJECTIVE

Our neonatal intensive care unit (NICU) saw an increase in Staphylococcus aureus (SA) infections-methicillin-resistant SA (MRSA) infections increased from 2.1/10,000 patient days (PD) to 5.1/10,000 PD, and methicillin-sensitive SA (MSSA) infections from 1.2/10,000 PD to 3.9/10,000 PD. This quality improvement project aimed to decrease the rates of SA infections to less than 2.0/10,000 PD, and to determine the rate of SA decolonization.

METHODS

Infection prevention interventions targeted patient factors (SA surveillance, patient cohorting, decolonization protocol), provider factors (provider cohorting, enhanced hand hygiene) and environmental factors (room structure, equipment optimization).

RESULTS

The rates of MRSA and MSSA infections decreased to 0.6/10,000 PD and 0.7 infections/10,000 PD respectively. Persistent decolonization of SA was successful in 67% of colonized patients.

CONCLUSIONS

Specific interventions targeting patient, provider, and environmental factors, including the implementation of a SA decolonization protocol, were successful in decreasing the incidence of SA infections in neonates.

Visitor restriction during the COVID-19 pandemic did not impact rates of Staphylococcus aureus colonization in the NICU patients

OBJECTIVES

In our neonatal intensive care unit (NICU), patients are screened for colonization with Staphylococcus aureus (S. aureus) and decolonized if positive. During the COVID-19 pandemic, our NICU significantly limited its visitor policy. We assessed for a difference between S. aureus colonization rates before and after the visitor policy change, which coincided with the exponential rise of COVID-19 cases in New York City (NYC).

METHODS

We calculated rates of newly S. aureus colonized NICU patients during January to June 2020 and compared rates pre- and post-implementation of the new visitor policy. Additionally, we obtained the weekly incidence of COVID-19 in NYC and assessed for a correlation between COVID-19 rates and S. aureus colonization.

RESULTS

The number of newly colonized patients per thousand patient days was 4.65 pre- and 3.95 post-implementation of the new visitor policy. The difference was not statistically significant (p=0.66). Furthermore, there was no correlation between the incidence of COVID-19 in NYC and the rates of S. aureus colonization in our NICU (R²=0.02).

CONCLUSIONS

Our results suggest that limiting visitation of patients is not associated with a decrease in S. aureus colonization rate. Hospital unit leaders may need to focus on other strategies in order to reduce colonization.

Molecular epidemiology of methicillin-sensitive Staphylococcus aureus in the neonatal intensive care unit

BACKGROUND

Staphylococcus aureus-both meticillin-resistant S. aureus (MRSA) and meticillin-sensitive S. aureus (MSSA)-is a major cause of neonatal infections. Infection control measures have not lowered the incidence of MSSA infections to the same degree as that of MRSA infections.

AIM

To investigate the transmission pathway of MSSA in neonatal intensive care unit (NICU) using genetic analysis.

METHODS

We swab-tested neonatal patients, their parents, and healthcare workers (HCW) in the NICU at our hospital at the time of hospitalisation and then every month thereafter from 1^st October 2018 to 31^st March 2019. We performed whole-genome sequencing (WGS) to test for MSSA strains. Multilocus sequence typing (MLST) and single nucleotide polymorphism (SNP) analysis were used to identify strains and understand their relatedness.

FINDINGS

There were 16 MSSA-positive patients. Four MSSA-positive patients shared strains from the same phylogenetic groups as those of HCW. One presented the same strain as the parent. MSSA-positive twin neonates shared the same strain. Ten had sporadic strains; 32 of the ninety-seven tested healthcare workers were MSSA positive.

CONCLUSION

The findings of this study suggest that the route of transmission of MSSA in NICU may be through MSSA in the hospital environment in addition to horizontal transmission via healthcare workers. Along with hand hygiene with alcohol, thorough environmental maintenance and parental education are important for infection control in NICUs targeting MSSA.

Infection prevention for extremely low birth weight infants in the NICU

Extremely preterm infants are particularly vulnerable to systemic infections secondary to their immature immune defenses, prolonged hospitalizations, delays in enteral feeding, early antibiotic exposure, and need for life-sustaining invasive interventions. There have been several evidence-based practices for infection prevention in this population, such as human milk feedings, utilization of "bundle checklists" and decolonization of pathogenic organisms. Other practices, such as the use of probiotics, human milk-derived fortifiers, and antifungal prophylaxis are more controversial and require further investigation regarding the risks and benefits of such interventions. This chapter examines the susceptibility of the preterm newborn infant to invasive infections and describes several strategies for infection prevention, along with the associated limitations of such practices. It also addresses the various gaps in our understanding of preventing infections in this population, and the need for additional large multi-center randomized controlled trials. Additionally, the role of the SARs-CoV-2 global pandemic and associated strategies for infection prevention in the NICU are discussed.

Management and Prevention of Staphylococcus aureus Infections in Children

Staphylococcus aureus is a common skin commensal with the potential to cause severe infections resulting in significant morbidity and mortality. Up to 30% of individuals are colonized with S aureus, though infection typically does not occur without skin barrier disruption. Infection management includes promptly addressing the source of infection, including sites of metastatic infection, and initiation of effective antibiotics, which should be selected based on local antibiotic susceptibility patterns. Given that S aureus colonization is a risk factor for infection, preventive strategies are aimed at optimizing hygiene measures and decolonization regimens for outpatients and critically ill children with prolonged hospitalizations.

Spa Typing of Staphylococcus aureus in a Neonatal Intensive Care Unit During Routine Surveillance

BACKGROUND

Staphylococcus aureus protein A (spa) typing can be used to expand characterization of the epidemiology of methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in neonatal intensive care units (NICU).

METHODS

From January 2017 to June 2018, twice-monthly surveillance for S. aureus was performed in an academically affiliated NICU. Decolonization of infants colonized with S. aureus included chlorhexidine gluconate bathing and/or mupirocin for those with mupirocin-susceptible strains. Spa typing and mupirocin-resistance testing were performed. Demographic and clinical characteristics were compared between infants colonized with MSSA vs MRSA and infants with and without the most common MSSA spa type, MSSA-t279.

RESULTS

Overall, 14% and 2% of 1556 hospitalized infants had positive surveillance cultures for MSSA and MRSA, respectively. Thirty-six infants harbored unique MSSA spa types, 5 infants harbored unique MRSA spa types, and 30 MSSA and 6 MRSA spa types were identified in ≥2 infants. No outbreaks were identified during the study period. MSSA-t279 was isolated from 3% of infants and largely detected from infants hospitalized in one section of the NICU; 96% of t279 isolates were mupirocin resistant. Infection rates, length of hospitalization, and mortality were similar among infants initially colonized with t279 vs other MSSA spa types.

CONCLUSIONS

The MSSA colonization burden was 5-fold larger than that of MRSA. Numerous unique spa types were identified. The most common spa type, MSSA-t279, was not associated with increased morbidity or mortality but was mupirocin resistant and associated with clustered NICU beds. This suggests potential transmission from the environment, shared staff, and/or workflow issues requiring further study. Other decolonization strategies for S. aureus in the NICU are needed.

Expanding antimicrobial stewardship strategies for the NICU: Management of surgical site infections, perioperative prophylaxis, and culture negative sepsis

OBJECTIVE

To review antibiotic stewardship strategies for neonatal intensive care units (NICU) in the areas of management of surgical site infections, perioperative prophylaxis and culture negative late onset sepsis.

FINDING

Review of local microbiology, stratification of surgical procedures by risk of contamination of the surgical site, and adherence to evidence-based principles of perioperative antibiotic administration (targeted therapy, effective dosing, appropriate timing and limiting duration post-operatively) can help to minimize unnecessary antibiotic use for neonatal surgery. Creating a late onset sepsis case definition, appropriate collection and interpretation of blood cultures, and instituting antibiotic time-outs can minimize the overuse of antibiotics for culture negative sepsis.

CONCLUSION

Effective implementation of these antimicrobial stewardship strategies in the NICU can reduce unnecessary antimicrobial use and limit the emergence of resistant pathogens.

Effect of Contact Precautions on Staphylococcus aureus and Clinical Outcomes of Colonized Patients in the Neonatal Intensive Care Unit

BACKGROUND

Staphylococcus aureus is a common pathogen in neonatal intensive care units (NICUs), yet little is known about the effect of contact precautions and clinical outcomes of colonized patients.

METHODS

Retrospective cohort study of all neonates from August 2014 to November 2018 colonized with either methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA) and select noncolonized patients at two neonatal intensive care units at the University of California, Los Angeles. Outcomes during two time periods (during and after the use of contact precautions) were assessed.

RESULTS

A total of 234 patients were included in the study: 83 colonized and 151 noncolonized patients. There was a fourfold higher incidence of MSSA colonization versus MRSA (P < 0.001). There was a higher incidence of positive surveillance cultures after contact precautions were discontinued (P = 0.01), but this did not correlate with a higher incidence of invasive cultures (P = 0.475). There were twice as many MSSA invasive cultures than MRSA, but a higher rate of invasion with MRSA (P < 0.05). Colonized patients were more likely to develop an invasive infection than noncolonized (P = 0.003 MRSA; P = 0.004 MSSA). When controlling for gestational age and surgical interventions, colonization was more likely to be associated with skin and soft tissue infections (P < 0.001) and a longer length of stay by a mean of 27.8 days (P < 0.0001).

CONCLUSIONS

Contact precautions resulted in a lower incidence of colonization without a difference in invasive cultures in our NICUs. Those colonized with S. aureus had a higher incidence of skin and soft tissue infections and a longer NICU length of stay.

The effect of routine surveillance and decolonization on the rate of Staphylococcus aureus infections in a level IV neonatal intensive care unit

OBJECTIVE

To evaluate the impact of active surveillance cultures (ASC) for Staphylococcus aureus (SA) and decolonization on the rate of infection in neonates in a neonatal intensive care unit (NICU).

STUDY DESIGN

Using a quasi-experimental design with control groups, rates of SA infections before and after implementing weekly ASC and topical mupirocin decolonization in a level IV NICU were compared. Comparators were the rates of gram negative bloodstream infections (BSI) and of SA BSI at an affiliated NICU where the intervention was not implemented.

RESULT

There was a 77% (p < 0.010) reduction in rate of NICU-wide methicillin-susceptible SA (MSSA) BSI, but no significant change in rate of methicillin-resistant SA BSI, likely due to a prevalent mupirocin-resistant clone. Rates of gram negative BSI and SA BSI at an affiliated NICU did not change significantly.

CONCLUSION

Weekly ASC and decolonization were associated with a unit-wide reduction in MSSA infections in a NICU.

Antibiotic Resistance in the Neonatal Intensive Care Unit

Antibiotic-resistant bacteria are an increasing problem in the NICU. Ineffective empiric antibiotic therapy is associated with increased risk for morbidity and mortality. Organisms that are resistant to multiple antimicrobial agents (multidrug-resistant organisms) are particularly problematic. These organisms may be transmitted to infants if infection control practices are not adhered to, or they may be created by antibiotic exposure. Therefore, meticulous infection prevention-including hand hygiene, surveillance cultures, contact precautions, and selective decolonization-and antibiotic stewardship are important strategies to minimize drug resistance in the NICU.

Bacterial invasive infections in a neonatal intensive care unit: a 13 years microbiological report from an Italian tertiary care centre

INTRODUCTION

To evaluate the aetiology of neonatal invasive diseases (positive cultures from blood or cerebrospinal fluid, CSF) due to bacteria other than coagulase-negative staphylococci in a large tertiary care centre and compare with results of surveillance cultures.

METHODS

Retrospective analysis of microbiological data of children admitted in neonatal intensive care unit (NICU) of a large tertiary care centre from 2005 to 2018.

RESULTS

230 bacterial strains, 223 from blood and 7 from CSF, respectively, were detected as cause of invasive infections, while 152 were detected in surveillance cultures. Methicillin-susceptible Staphylococcus aureus (MSSA) was the most frequently isolated pathogen both in invasive infections (18%) and colonizations (23%) followed by Escherichia coli (16% on invasive disease and 20% of colonizations). Other common bacteria include Enterococcus faecalis and Streptococcus agalactiae for invasive disease and methicillin-resistant Staphylococcus aureus in colonizations. Invasive infection was due to a pathogen detected in surveillance cultures in 33% of cases. In more than 50% of invasive diseases the identified pathogen was not present in surveillance cultures.

CONCLUSIONS

The high percentage of invasive infections due to bacteria not previously identified in surveillance cultures raises doubts about the efficiency of this procedure and highlights the need to search for alternative infection sources. This finding and the high prevalence of invasive infections due to nosocomial pathogens such as Staphylococcus aureus could be the result of horizontal transmission between patients through the hands of health care professionals, emphasizing once again the importance of applying stringent hand hygiene procedures and isolation standards.

Role of surveillance cultures in infection control

Hospital-acquired infections are a known menace to the primary disease, for which a patient is admitted. These infections are twenty times more common in developing countries than in the developed ones. Surveillance for colonised patients can be passive or active process. In many hospitals, active surveillance culture for certain sentinel organisms followed by contact precautions for the same is an important part of infection control policy. Specific measures can be taken on early detection of multidrug-resistant organism, allowing prevention of widespread transmission in hospitals. Cultures are the most conventional and economical microbiological method of detection. The cost of active surveillance is a major challenge, especially for developing nations. These nations lack basic infrastructure and have logistic issues. The guidelines regarding this are not very clearly delineated for developing countries. Each hospital has its own challenges and the process is to be tailor-made accordingly. The following review delineates the various aspects of active surveillance for the colonisation of various organisms and the advantages and disadvantages of the same.

Colonization profile and duration by multi-resistant organisms in a prospective cohort of newborns after hospital discharge

The aim of this study was to determine the spontaneous decolonization period and characteristics in a prospective cohort of newborns colonized by multidrug-resistant organisms, after their discharge from the neonatal intensive care unit. Multidrug resistance is defined as bacterial non-susceptibility to ≥ 1 agent of ≥ 3 antimicrobial categories. In total, 618 newborns were included in the study, of which 173 (28.0%) presented a positive culture for multidrug-resistant microorganisms, and of these, 52 (30.1%) were followed up in this study. The most frequent intrinsic factors were be born by cesarean section (86.5%), prematurity (84.6%), and very low birth weight (76.9%). The extrinsic factors were having remained hospitalized for an average of 27 days, during which 67.3% were submitted to invasive procedures and 88.5% received antimicrobials. The intrinsic and extrinsic factors of newborns were not associated to a decolonization period longer or shorter than 3 months, which was the average period of decolonization found in the present study. From the totality of colonization cultures sampled at hospital discharge, the Gram-negative Extended Spectrum β-lactamase producing bacteria were the most common, with 28.9% of babies colonized by Klebsiella spp. The median period of decolonization by multidrug-resistant microorganisms in the newborns population after hospital discharge was 3 months, but was highly dependent on the microbial species, and this period was not associated to any intrinsic and extrinsic factors of the newborn.

Effect of Treating Parents Colonized With Staphylococcus aureus on Transmission to Neonates in the Intensive Care Unit: A Randomized Clinical Trial

IMPORTANCE

Staphylococcus aureus is a leading cause of health care-associated infections in the neonatal intensive care unit (NICU). Parents may expose neonates to S aureus colonization, a well-established predisposing factor to invasive S aureus disease.

OBJECTIVE

To test whether treating parents with intranasal mupirocin and topical chlorhexidine compared with placebo would reduce transmission of S aureus from parents to neonates.

DESIGN, SETTING, AND PARTICIPANTS

Double-blinded randomized clinical trial in 2 tertiary NICUs in Baltimore, Maryland. Neonates (n = 236) with S aureus-colonized parent(s) were enrolled. The study period was November 7, 2014, through December 13, 2018.

INTERVENTIONS

Parents were assigned to intranasal mupirocin and 2% chlorhexidine-impregnated cloths (active treatment, n = 117) or petrolatum intranasal ointment and nonmedicated soap cloths (placebo, n = 119) for 5 days.

MAIN OUTCOMES AND MEASURES

The primary end point was concordant S aureus colonization by 90 days, defined as neonatal acquisition of an S aureus strain that was the same strain as a parental strain at time of screening. Secondary outcomes included neonatal acquisition of any S aureus strain and neonatal S aureus infections.

RESULTS

Among 236 randomized neonates, 208 were included in the analytic sample (55% male; 76% singleton births; mean birth weight, 1985 g [SD, 958 g]; 76% vaginal birth; mean parent age, 31 [SD, 7] years), of whom 18 were lost to follow-up. Among 190 neonates included in the analysis, 74 (38.9%) acquired S aureus colonization by 90 days, of which 42 (56.8%) had a strain concordant with a parental baseline strain. In the intervention and placebo groups, 13 of 89 neonates (14.6%) and 29 of 101 neonates (28.7%), respectively, acquired concordant S aureus colonization (risk difference, -14.1% [95% CI, -30.8% to -3.9%]; hazard ratio [HR], 0.43 [95.2% CI, 0.16 to 0.79]). A total of 28 of 89 neonates (31.4%) in the intervention group and 46 of 101 (45.5%) in the control group acquired any S aureus strain (HR, 0.57 [95% CI, 0.31 to 0.88]), and 1 neonate (1.1%) in the intervention group and 1 neonate (1.0%) in the control group developed an S aureus infection before colonization. Skin reactions in parents were common (4.8% intervention, 6.2% placebo).

CONCLUSIONS AND RELEVANCE

In this preliminary trial of parents colonized with S aureus, treatment with intranasal mupirocin and chlorhexidine-impregnated cloths compared with placebo significantly reduced neonatal colonization with an S aureus strain concordant with a parental baseline strain. However, further research is needed to replicate these findings and to assess their generalizability.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02223520.

A cost analysis of active surveillance culture in a neonatal intensive care unit

Active surveillance culture (ASC) in neonatal intensive care units (NICUs) has been implemented to monitor horizontal transmission and choose appropriate antimicrobials when neonates experience late-onset infections (LOIs). To perform a cost analysis of ASC in the NICU, we evaluated data from a NICU ward in a Japanese community hospital. This was a retrospective study of neonates admitted to the NICU of Nara Prefecture General Medical Center, Nara City, Japan, from April 2012 to May 2017. We implemented biweekly ASC (nasal, stool and umbilical cultures) during this period. We assessed the detection rate for methicillin-sensitive and -resistant S. aureus (MSSA and MRSA) in each culture and reviewed the cases of LOI. Among the 785 cases, MSSA and MRSA were detected in 158 and 75 cases, respectively. Nasal culture was the most sensitive method for detecting MSSA and MRSA. Three cases benefitted from changing the empiric treatment based on previous ASC results, with an annual cost of ¥808,331 (£5773.80 or $7282.30) for ASC. The total cost per one benefited case during the study period was calculated as ¥1,392,126 (£9943.80 or $12,541.70). The total cost per benefited case in risk factor targeted ASC, nasal culture targeted ASC and MRSA-targeted ASC was ¥1,332,264 (£9516.20 or $12,002.30), ¥692,222 (£4944.40 or $6236.20) and ¥858,547 (£6132.50 or $7734.70), respectively. Considering the frequency of S. aureus detection and the cost of each culture, our ASC was modified to use only nasal cultures. This study suggests that the cost performance of ASC should be evaluated with consideration of the characteristics of each NICU.

Combination of Nasal and Expanded Skin Swabs Enhances the Detection Rate of Staphylococcus aureus Colonization in Premature Infants

Nasal cultures are commonly used to detect carriers of Staphylococcus aureus (SA) in infants. Combination of nasal and skin swabs has been shown to enhance the detection rate of SA colonization in adult hospitalized patients. Combining nasal swabs with expanded body skin swabs enhanced detection of SA colonization in premature infants in a tertiary care neonatal department.

The Association Between the Developing Nasal Microbiota of Hospitalized Neonates and Staphylococcus aureus Colonization

Background

Hospitalized neonates are at high risk for invasive Staphylococcus aureus infections. S. aureus nasal colonization often precedes infection. The nasal microbiota may preclude or support colonization. We aimed to characterize and compare the nasal microbiota of hospitalized neonates who acquire S. aureus colonization (cases) and those who do not acquire S. aureus (controls).

Methods

We obtained residual nares samples from hospitalized neonates who were screened weekly for S. aureus nasal colonization and treated with intranasal mupirocin if colonized. Eight cases were matched based on chronologic age and systemic antibiotic exposure to 7 controls. We extracted DNA, sequenced the V3-V4 region of the 16s rRNA gene, and performed taxonomic assignments. The bacterial species richness, relative abundance, and in silico predicted gene content were compared between cases and controls at 7 days before S. aureus acquisition, at the time of acquisition, and 7 days after acquisition and treatment.

Results

Common commensals including nondiphtheriae corynebacteria were more abundant in the nares of controls and Rothia mucilaginosa was more abundant in cases 7 days after intranasal mupirocin treatment than in cases 7 days before S. aureus acquisition. Controls and treated cases had a higher predicted abundance of genes contributing to the synthesis of certain antimicrobial compounds than in cases before S. aureus acquisition.

Conclusions

Neonates without S. aureus nasal colonization had a higher abundance of bacterial species that antagonize S. aureus directly or by selecting for beneficial co-colonizers. These differences may inform novel S. aureus infection prevention strategies in high-risk infants.

Prevention Strategies for Recurrent Community-Associated Staphylococcus aureus Skin and Soft Tissue Infections

PURPOSE OF REVIEW

Staphylococcus aureus skin and soft tissue infections (SSTI) are a major source of morbidity. More than half of patients experiencing SSTI will have at least one recurrent infection. These infections frequently cluster in households. Given the burden these infections pose to patients and healthcare, prevention strategies are of major clinical importance and represent an active area of research. Bacterial colonization is frequently an early and critical step in the pathogenesis of infection. As such, strategies to prevent reinfection have aimed to decrease staphylococcal colonization of the skin and mucus membranes, a process referred to as decolonization.

RECENT FINDINGS

Treatment of acute SSTI with incision and drainage and systemic antibiotics is the mainstay of therapy for healing of the acute infection. Systemic antibiotics also provide benefit through reduced incidence of recurrent SSTI. Education for patients and families regarding optimization of personal and household hygiene measures, and avoidance of sharing personal hygiene items, is an essential component in prevention efforts. For patients experiencing recurrent SSTI, or in households in which multiple members have experienced SSTI, decolonization should be recommended for all household members. A recommended decolonization regimen includes application of intranasal mupirocin and antiseptic body washes with chlorhexidine or dilute bleach water baths. For patients who continue to experience recurrent SSTI, periodic decolonization should be considered. Personal decolonization with topical antimicrobials and antiseptics reduces the incidence of recurrent S. aureus SSTI. Future avenues for investigation include strategies for household environmental decontamination as well as manipulation of the host microbiota.

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.

Case report: Staphylococcus aureus endocarditis in 2 premature newborns

RATIONALE

Neonatal infectious endocarditis (IE) in a healthy heart is rare. The infectious agents most frequently found in newborns are Staphylococcus aureus and fungi. Infection at the site of central intravenous catheter is generally thought to be the cause of this pathology.

PATIENT CONCERNS

We present 2 cases of premature newborns whose condition is evolving positively. They presented S aureus endocarditis during their first week of life.

DIAGNOSIS

Modified Duke diagnostic criteria-from clinical, echocardiogram and microbiological findings-based on those used for adults, can be used for children and newborns, but the very low prevalence of neonatal IE often delays diagnosis. Diagnosis on the basis of transthoracic heart ultrasound requires an extension report, given the very high embolic risk.

INTERVENTION

In the large majority of cases, long-term antibiotic therapy efficaciously treats the infection, although sometimes surgery is necessary. These 2 newborns needed only antibiotic therapy.

OUTCOME

Despite the various complications, especially embolic, these 2 children are followed and are doing well.

LESSONS

Long-term pediatric heart monitoring combined with prophylactic antibiotics are essential, according to the European Society of Cardiology guidelines.

Epidemiology and risk factors for recurrent Staphylococcus aureus colonization following active surveillance and decolonization in the NICU

OBJECTIVES

To examine neonatal risk factors associated with recurrent Staphylococcus aureus colonization and to determine the genetic relatedness of S. aureus strains cultured from neonates before and after decolonization.Study designSingle-center retrospective cohort study of neonates admitted to the neonatal intensive care unit (NICU) from April 2013 to December 2015, during which weekly nasal cultures from hospitalized NICU patients were routinely obtained for S. aureus surveillance.

SETTING

Johns Hopkins Hospital's 45-bed level IV NICU in Baltimore, Maryland.

METHODS

Demographics and clinical data were collected on all neonates admitted to the NICU with S. aureus nasal colonization who underwent mupirocin-based decolonization during the study period. A decolonized neonate was defined as a neonate with ≥1 negative culture after intranasal mupirocin treatment. Pulsed-field gel electrophoresis was used for strain typing.

RESULTS

Of 2,060 infants screened for S. aureus, 271 (13%) were colonized, and 203 of these 271 (75%) received intranasal mupirocin. Of those treated, 162 (80%) had follow-up surveillance cultures, and 63 of these 162 infants (39%) developed recurrent colonization after treatment. The S. aureus strains were often genetically similar before and after decolonization. The presence of an endotracheal tube or nasal cannula/mask was associated with an increased risk of recurrent S. aureus colonization (hazard ratio [HR], 2.65; 95% confidence interval [CI], 1.19-5.90; and HR, 2.21; 95% CI, 1.02-4.75, respectively).

CONCLUSION

Strains identified before and after decolonization were often genetically similar, and the presence of invasive respiratory devices increased the risk of recurrent S. aureus nasal colonization in neonates. To improve decolonization efficacy, alternative strategies may be needed.

Evaluating a neonatal intensive care unit MRSA surveillance programme using agent-based network modelling

BACKGROUND

Surveillance for meticillin-resistant Staphylococcus aureus (MRSA) in neonatal intensive care units (NICUs) is a commonplace infection prevention strategy, yet the optimal frequency with which to monitor the unit is unknown.

AIM

To compare various surveillance frequencies using simulation modelling.

METHODS

One hundred NICU networks of 52 infants were simulated over a six-month period to assess MRSA transmission. Unit-wide surveillance occurred every N weeks where N={1,2,3,4}, and was compared with the current NICU policy of dynamic surveillance (i.e. weekly when at least one positive screen, otherwise every three weeks). For each surveillance period, colonized infants received a decolonization regimen (56% effective) and were moved to isolation rooms, if available.

FINDINGS

As the surveillance frequency increased, the mean number of MRSA-colonized infants decreased, from a high of 2.9 (four-weekly monitoring) to a low of 0.6 (weekly monitoring) detected per episode. The mean duration of colonization decreased from 307 h (four-weekly monitoring) to 61 h (weekly monitoring). Meanwhile, the availability of isolation rooms followed an inverse relationship: as surveillance frequency increased, the availability of isolation rooms decreased (61% isolation success rate for four-weekly monitoring vs 49% success rate for weekly monitoring). The dynamic policy performed similar to a biweekly programme.

CONCLUSIONS

An effective MRSA surveillance programme needs to balance resource availability with potential for harm due to longer colonization periods and opportunity for development of invasive disease. While more frequent monitoring led to greater use of a decolonization regimen, it also reduced the likelihood of isolation rooms being available.

Manipulating the microbiome: evolution of a strategy to prevent S. aureus disease in children

Hospitalized infants have the highest rates of invasive Staphylococcus aureus disease of any population and infection control strategies such as decolonization have been insufficient. For decades, researchers began studying the microbiome in search of new prevention strategies. The resident microbiota was found to be closely associated with susceptibility and at times, resistance to S. aureus colonization. The evolution of nucleic acid based techniques has enhanced our understanding of the complex relationship between the nasal microbiota and S. aureus colonization. We review what is known about bacterial communities in the nasal cavity of infants and discuss how future microbiome studies may help identify novel interventions to protect high-risk infants from S. aureus disease.

A Network Model of Hand Hygiene: How Good Is Good Enough to Stop the Spread of MRSA?

BACKGROUND Simulation models have been used to investigate the impact of hand hygiene on methicillin-resistant Staphylococcus aureus (MRSA) transmission within the healthcare setting, but they have been limited by their ability to accurately model complex patient-provider interactions. METHODS Using a network-based modeling approach, we created a simulated neonatal intensive care unit (NICU) representing the potential for per-hour infant-infant MRSA transmission via the healthcare worker resulting in subsequent colonization. The starting prevalence of MRSA colonized infants varied from 2% to 8%. Hand hygiene ranged from 0% (none) to 100% (theoretical maximum), with an expected effectiveness of 88% inferred from literature. RESULTS Based on empiric care provided within a 1-hour period, the mean number of infant-infant MRSA transmissible opportunities per hour was 1.3. Compared to no hand hygiene and averaged across all initial colonization states, colonization was reduced by approximately 29%, 51%, 67%, 80%, and 86% for the respective levels of hygiene: 24%, 48%, 68%, 88%, and 100%. Preterm infants had a 61% increase in MRSA colonization, and mechanically ventilated infants had a 27% increase. CONCLUSIONS Even under optimal hygiene conditions, horizontal transmission of MRSA is possible. Additional prevention paradigms should focus on the most acute patients because they are at greatest risk. Infect Control Hosp Epidemiol 2017;38:945-952.

The Microorganisms on Nurses' and Health Care Workers' Uniforms in the Intensive Care Units

The objective of this study was to identify the types of microorganisms present on uniforms of nurses, physicians, respiratory therapist, students, and housekeepers in intensive care units (ICUs). A convenience sampling was used to recruit the participants ( N = 115) who work at military hospital in Jordan. Environmental cultures ( N = 305) were taken from the participants who were nurses, physicians, students, respiratory therapists, and housekeepers. The number of participating nurses was 58 (50.43%). There were 24 types of microorganisms found on the participants' uniforms. Staphylococcus epidermidis was found 59 times (61.3%) on the three areas of uniform culture. High level of contamination was found among all the participants, and it was the highest in physicians (85%) followed by nurse (79.3%) (χ² = 24.87, p < .001). None of the participants' characteristics have correlated significantly with the uniform contamination. High percentages of uniform's contamination among all those who work in the ICUs were found.

Bacterial Infections in Neonates Following Mupirocin-Based MRSA Decolonization: A Multicenter Cohort Study

OBJECTIVE To characterize the risk of infection after MRSA decolonization with intranasal mupirocin. DESIGN Multicenter, retrospective cohort study. SETTING Tertiary care neonatal intensive care units (NICUs) from 3 urban hospitals in the United States ranging in size from 45 to 100 beds. METHODS MRSA-colonized neonates were identified from NICU admissions occurring from January 2007 to December 2014, during which a targeted decolonization strategy was used for MRSA control. In 2 time-to-event analyses, MRSA-colonized neonates were observed from the date of the first MRSA-positive surveillance screen until (1) the first occurrence of novel gram-positive cocci in sterile culture or discharge or (2) the first occurrence of novel gram-negative bacilli in sterile culture or discharge. Mupirocin exposure was treated as time varying. RESULTS A total of 522 MRSA-colonized neonates were identified from 16,144 neonates admitted to site NICUs. Of the MRSA-colonized neonates, 384 (74%) received mupirocin. Average time from positive culture to mupirocin treatment was 3.5 days (standard deviation, 7.2 days). The adjusted hazard of gram-positive cocci infection was 64% lower among mupirocin-exposed versus mupirocin-unexposed neonates (hazard ratio, 0.36; 95% confidence interval [CI], 0.17-0.76), whereas the adjusted hazard ratio of gram-negative bacilli infection comparing mupirocin-exposed and -unexposed neonates was 1.05 (95% CI, 0.42-2.62). CONCLUSIONS In this multicentered cohort of MRSA-colonized neonates, mupirocin-based decolonization treatment appeared to decrease the risk of infection with select gram-positive organisms as intended, and the treatment was not significantly associated with risk of subsequent infections with organisms not covered by mupirocin's spectrum of activity. Infect Control Hosp Epidemiol 2017;38:930-936.

Active Surveillance Cultures and Targeted Decolonization Are Associated with Reduced Methicillin-Susceptible Staphylococcus aureus Infections in VLBW Infants

BACKGROUND

Methicillin-susceptible Staphylococcus aureus (MSSA) is a major contributor to infectious episodes of very low birth weight infants (VLBWI), resulting in significant morbidity and mortality.

OBJECTIVE

To examine the efficacy and safety of surveillance cultures and the decolonization of MSSA-colonized VLBWI.

METHODS

VLBWI admitted to our neonatal wards in 2011-2016 were retrospectively analyzed. Rates of MSSA-attributable infections were compared before and after the implementation of active surveillance cultures and the decolonization of MSSA-colonized patients. The mupirocin susceptibility of isolated MSSA strains was routinely tested.

RESULTS

A total of 1,056 VLBWI were included in the study, 552 in the pre-intervention period and 504 in the post-intervention period. The implementation of surveillance cultures and decolonization of colonized patients resulted in a 50% reduction of incidence rates per 1,000 patient-days of MSSA-attributable infections (1.63 [95% CI 1.12-2.31] vs. 0.83 [95% CI 0.47-1.35], p = 0.024). No adverse effects were observed from application of the decolonization protocol with mupirocin and octenidin. No mupirocin-resistant MSSA strains were detected during the study period.

CONCLUSION

Implementation of an active surveillance and decolonization protocol resulted in a reduction of MSSA-attributable infections in VLBWI.

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.

Epidemiology and microbiological characterization of clinical isolates of Staphylococcus aureus in a single healthcare region of the UK, 2015

We investigated the epidemiology and characterization of isolates of Staphylococcus aureus within the Yorkshire and Humber (YH) region in the UK. In July 2015, each laboratory within YH (n = 14) was assigned two consecutive days during which all clinical isolates of S. aureus were collected. Isolates were tested for antibiotic susceptibilities and the presence of genes encoding methicillin resistance (mecA and mecC), Panton–Valentine leukocidin (PVL) (lukS-PV), and efflux-mediated chlorhexidine resistance (qacA); isolates were also characterized by spa-types. Minimum inhibitory concentrations (MICs) to chlorhexidine were determined by the broth dilution method. Of 520 isolates collected, 6·2% were methicillin-resistant S. aureus (MRSA, all mecA-positive) and mupirocin resistance was low [0·8%, 95% confidence interval (CI) 0·3–2·0] and only found in MRSA. Carriage of the qacA gene was identified in 1·7% (95% CI 0·8–3·3) of isolates and 3·5% (95% CI 2·2–5·4) had a chlorhexidine MIC of 4 mg/l. The PVL gene was infrequent (3·7%, 95% CI 2·4–5·6). Genotyping identified 234 spa-types that mapped to 22 clonal complexes. Comparison of these current data with previous work suggest that the widespread use of staphylococcal decolonization regimens over the past decade or more has not had an adverse impact on resistance rates, PVL carriage or the prevalence of specific S. aureus lineages.