Risk Factors for Staphylococcus aureus Acquisition in the Neonatal Intensive Care Unit: A Matched Case-Case-Control Study

Influence of transition from open bay units to single room units in a neonatal intensive care unit on hospital transmission of multi-drug-resistant Enterobacterales

BACKGROUND

It was shown previously that changing the design of a hospital neonatal intensive care unit (NICU) from open bay units (OBUs) to single room units (SRUs) was not associated with a reduction in Gram-negative multi-drug-resistant organism (MDRO) colonization rates. It was therefore hypothesized that colonization mainly occurs vertically, or through parents and healthcare workers, and not through environmental factors, and that transition to SRUs would not decrease the number of clusters of MDROs with an epidemiological link. To investigate this, core-genome multi-locus sequence typing (cgMLST) was applied on MDROs cultured from infants at the study hospital.

METHODS

This retrospective cohort study included all infants carrying MDROs admitted to the NICU of a tertiary care academic hospital 2 years prior to the transition from OBUs to SRUs in May 2017, and 1.5 years after the transition (2018-2020).

RESULTS

In total, 55 infants were diagnosed with MDRO carriership. Isolates were available from 49 infants for cgMLST. In the OBU period, one cluster involving four of 20 (20%) infants was identified, and in the SRU period, four clusters involving nine of 29 (31%) infants were identified. It was possible to make an epidemiological link in all four SRU MDRO clusters, but this was not possible for the OBU cluster. In the latter case, transmission from an environmental source on the ward seemed likely.

CONCLUSION

After transition to SRUs, there was no decrease in the number of clusters of MDROs with an epidemiological link, suggesting that nursing infants in an NICU with an SRU design is not, in itself, protective against the acquisition of MDROs.

Clinical, humanistic and economic outcomes, including experiencing of patient safety events, associated with admitting patients to single rooms compared with shared accommodation for acute hospital admissions: a systematic review and narrative synthesis

OBJECTIVES

Assess the impact of single rooms versus multioccupancy accommodation on inpatient healthcare outcomes and processes.

DESIGN

Systematic review and narrative synthesis.

DATA SOURCES

Medline, Embase, Google Scholar and the National Institute for Health and Care Excellence website up to 17 February 2022.

ELIGIBILITY CRITERIA

Eligible papers assessed the effect on inpatients staying in hospital of being assigned to a either a single room or shared accommodation, except where that assignment was for a direct clinical reason like preventing infection spread.

DATA EXTRACTION AND SYNTHESIS

Data were extracted and synthesised narratively, according to the methods of Campbell et al. RESULTS: Of 4861 citations initially identified, 145 were judged to be relevant to this review. Five main method types were reported. All studies had methodological issues that potentially biased the results by not adjusting for confounding factors that are likely to have contributed to the outcomes. Ninety-two papers compared clinical outcomes for patients in single rooms versus shared accommodation. No clearly consistent conclusions could be drawn about overall benefits of single rooms. Single rooms were most likely to be associated with a small overall clinical benefit for the most severely ill patients, especially neonates in intensive care. Patients who preferred single rooms tended to do so for privacy and for reduced disturbances. By contrast, some groups were more likely to prefer shared accommodation to avoid loneliness. Greater costs associated with building single rooms were small and likely to be recouped over time by other efficiencies.

CONCLUSIONS

The lack of difference between inpatient accommodation types in a large number of studies suggests that there would be little effect on clinical outcomes, particularly in routine care. Patients in intensive care areas are most likely to benefit from single rooms. Most patients preferred single rooms for privacy and some preferred shared accommodation for avoiding loneliness.

PROSPERO REGISTRATION NUMBER

CRD42022311689.

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.

Impact of transition from open bay to single room design NICU on MDRO colonization rates

BACKGROUND

The influence of the neonatal intensive care unit (NICU) design on the acquisition of multidrug resistant organisms (MDRO) has not been well-documented.

AIM

To examine the effect of single room unit (SRU) versus open bay unit (OBU) design on the incidence of colonization with MDRO and third-generation cephalosporin resistant bacteria (3G-CRB) in infants admitted to the NICU.

METHODS

Retrospective cohort study, including all infants admitted to the NICU of a tertiary care academic hospital two years prior to and two years following the transition from OBU to SRU in May 2017. Weekly cultures of throat and rectum were collected to screen for MDRO carriership. Incidence of colonization (percentage of all infants and incidence density per 1,000 patient-days) with MDRO and 3G-CRB were compared between OBU and SRU periods.

FINDINGS

Incidence analysis of 1,293 NICU infants, identified 3.2% MDRO carriers (2.5% OBU, 4.0% SRU, n.s.), including 2.3% extended-spectrum β-lactamase producing Enterobacterales carriers, and 18.6% 3G-CRB carriers (17% OBU, 20% SRU, n.s.). No differences were found in MDRO incidence density per 1,000 patient-days between infants admitted to OBU (1.56) compared to SRU infants (2.63).

CONCLUSION

Transition in NICU design from open bay to single room units was not associated with a reduction in colonization rates with MDRO or 3G-CRB in our hospital. Further research on preventing the acquisition and spread of resistant bacteria at high-risk departments such as the NICU, as well as optimal ward design, are needed.

Risk factors for nosocomial methicillin resistant Staphylococcus aureus (MRSA) colonization in a neonatal intensive care unit: A Case-control study

AIM

To determine risk factors for MRSA colonization in a Level IV Neonatal Intensive Care Unit (NICU) independent of length of stay and gestational age in the context of a persistently circulating MRSA clone.

DESIGN

Retrospective matched case-control study.

SETTING

Level IV NICU PATIENTS: Infants admitted between April 4,2017- March 31,2018.

METHODS

Based on weekly surveillance cultures, infants who acquired MRSA were matched 1:1 with MRSA-negative control infants by duration of exposure (length of stay) and gestational age to determine risk factors for acquisition.

RESULTS

Fifty case infants were matched with controls. Isolates from 45 of the 50 cases were mupirocin-resistant and related by pulse-field gel electrophoresis. On matched univariable analysis, the following were significantly associated with a risk for MRSA acquisition: 1.Bed location in the acute area(P = 0.03), 2.Requirement of any level of respiratory support during the week prior to MRSA detection(P = 0.04), 3.Higher ATP pass rate (a measure of effectiveness of cleaning) during the week of and week prior(P = 0.01), 4.Higher MRSA colonization pressure during the week of and week prior(P< 0.0001), 5.Not having a hearing test during the time between the previous negative culture and MRSA acquisition(P = 0.01). A multivariable conditional logistic regression model (that excluded ATP pass rate) found that only colonization pressure was associated with acquisition of MRSA colonization.

CONCLUSIONS

In an outbreak setting, MRSA colonization pressure is significantly associated with MRSA acquisition in the NICU independent of length of stay and gestational age.

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.

Infection Prevention in the Neonatal Intensive Care Unit

Although many aspects of infection prevention and control (IPC) mirror institutional efforts, optimization of IPC practices in the neonatal intensive care unit requires careful consideration of its unique population and environment, addressed here for key IPC domains. In addition, innovative mitigation efforts to address challenges specific to limited resource settings are discussed.

A persistent recurring cluster of meticillin-resistant Staphylococcus aureus (MRSA) colonizations in a special care baby unit: a matched case-control study

BACKGROUND

Between August 2016 and November 2019, a cluster of babies colonized with meticillin-resistant Staphylococcus aureus (MRSA) was reported in a special care baby unit in northern England.

AIM

A case-control study was performed to identify the source and prevent further cases.

METHODS

Cases were admitted neonates colonized or infected with MRSA (spa type t316). A retrospective case-control study was performed with two matched controls per case. Exposures were determined by medical record review. Cases were compared with controls using conditional logistic regression. Environmental investigations and staff screening were undertaken.

FINDINGS

Thirty-one colonized cases were identified across the 3-year period, with no infections reported. Thirteen of the 31 cases were sequenced and were within a cluster of 25 single nucleotide polymorphisms, consistent with exposure to a common source over a prolonged period. Most MRSA cases had a prior negative screen (N=22, 71%). Environmental sampling and staff screening were performed on several occasions. In the analytical study, 31 cases were compared with 62 controls. One ward location and one healthcare worker were identified as significant exposures in the multi-variable analysis.

CONCLUSIONS

Due to the sporadic nature of the colonizations, it was hypothesized that MRSA was being introduced intermittently, likely by a colonized healthcare worker, with possible transmission between infants also occurring within each temporal cluster. It is recommended that transiently colonized healthcare workers should be considered as a source of MRSA during outbreaks. This study highlights the importance of analytic epidemiological studies in persistent outbreaks of MRSA.

Early Bacterial Colonization and Antibiotic Resistance Gene Acquisition in Newborns

Several studies have recently identified the main factors contributing to the bacterial colonization of newborns and the dynamics of the infant microbiome development. However, most of these studies address large time periods of weeks or months after birth, thereby missing on important aspects of the early microbiome maturation, such as the acquisition of antibiotic resistance determinants during postpartum hospitalization. The pioneer bacterial colonization and the extent of its associated antibiotic resistance gene (ARG) dissemination during this early phase of life are largely unknown. Studies addressing resistant bacteria or ARGs in neonates often focus only on the presence of particular bacteria or genes from a specific group of antibiotics. In the present study, we investigated the gut-, the oral-, and the skin-microbiota of neonates within the first 72 h after birth using 16S rDNA sequencing approaches. In addition, we screened the neonates and their mothers for the presence of 20 different ARGs by directed TaqMan qPCR assays. The taxonomic analysis of the newborn samples revealed an important shift of the microbiota during the first 72 h after birth, showing a clear site-specific colonization pattern in this very early time frame. Moreover, we report a substantial acquisition of ARGs during postpartum hospitalization, with a very high incidence of macrolide resistance determinants and mecA detection across different body sites of the newborns. This study highlights the importance of antibiotic resistance determinant dissemination in neonates during hospitalization, and the need to investigate the implication of the mothers and the hospital environment as potential sources of ARGs.

Private patient rooms and hospital-acquired methicillin-resistant Staphylococcus aureus: A hospital-level analysis of administrative data from the United States

OBJECTIVE

To use hospital-level data from the US to determine whether private patient rooms (PPRs) are associated with fewer in hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) infections.

METHODS

We retrospectively analyzed Texas Inpatient Public Use Data with discharges between September 2015 and August 2016 merged with American Hospital Association annual survey data. We used negative binomial regression to estimate the association between the proportion of PPRs within a hospital and the count of discharges with HA-MRSA infections, adjusting for potentially confounding variables.

RESULTS

We analyzed data for 340 hospitals and 2,670,855 discharges. HA-MRSA incidence within these hospitals was 386 per 100,000 discharges (95% CI: 379, 393) and, on average, 62.73% (95% CI: 58.99, 66.46) of rooms in these hospitals were PPRs. PPRs were significantly associated with fewer HA-MRSA infections (unadjusted IRR = 0.973, 95% CI: 0.968, 0.979; adjusted IRR = 0.992, 95% CI: 0.991, 0.994; p<0.001 for both); at the hospital level, as the percentage of PPRs increased, HA-MRSA infection rates decreased. This association was non-linear; in hospitals with few PPRs there was a stronger association between PPRs and HA-MRSA infection rate relative to hospitals with many PPRs.

CONCLUSION

We identified 0.8% fewer HA-MRSA infections for each 1% increase in PPRs as a proportion of all rooms, suggesting that private rooms provide substantial protection from HA-MRSA. Small changes may not induce significant improvements in HA-MRSA incidence, and hospitals seeking tangible benefits in HAI reduction likely need to markedly increase the proportion of PPRs through large-scale renovations. The effect of private rooms is disproportionate across hospitals. Hospitals with proportionately fewer PPRs stand to gain the most from adding additional PPRs, while those with an already high proportion of PPRs are unlikely to see large benefits. Our findings enable hospital administrators to consider potential patient safety benefits as they make decisions about facility design and renovation.

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.