Reducing Staphylococcus aureus infections in the neonatal intensive care unit

Staphylococcus aureus pneumonia in neonates: clinical patterns, laboratory findings and outcomes

BACKGROUND

Staphylococcus aureus (SA) pneumonia is a leading cause of neonatal morbidity and mortality, particularly with methicillin-resistant Staphylococcus aureus (MRSA). Despite its prevalence, limited studies have focused on clinical presentation, antimicrobial resistance patterns, and outcomes of SA pneumonia in neonates. This study aimed to explore the clinical features, laboratory findings, and outcomes of neonates with SA pneumonia at the National Children's Hospital, Vietnam.

METHODS

We conducted a retrospective observational study on 31 neonates diagnosed with SA pneumonia from January 2022 to June 2023. Clinical data, including demographic details, symptoms, white blood cell (WBC) count, C-reactive protein (CRP) levels, antimicrobial susceptibility, and radiological findings, were collected. We analyzed the antibiotic resistance patterns of SA and evaluated factors associated with vancomycin treatment failure.

RESULTS

Of the 31 neonates, 96.8 % were diagnosed with MRSA pneumonia. The main clinical symptoms were fever (77.4 %), tachypnea (83.9 %), and chest retraction (80.6 %). SA was primarily isolated from endotracheal fluid (71.0 %), pleural fluid (41.9 %), and both combined (51.6 %) with positive blood cultures. Complications were common, with pleural effusion in 54.8 %, pneumothorax in 48.4 %, necrotizing pneumonia in 25.8 %, and lung abscess in 29.0 % of cases. Vancomycin was the primary antibiotic administered, though treatment failure occurred in 38.7 % of cases, necessitating alternative antibiotics, particularly in patients with severe illness requiring mechanical ventilation, vasopressor support, and elevated CRP levels (>15 mg/L). Most strains were resistant to beta-lactam antibiotics but sensitive to vancomycin, linezolid, ciprofloxacin, and levofloxacin. The average hospital stay was 24.4 ± 12.6 days, with a mortality rate of 12.9 %, mainly due to severe respiratory failure and septic shock.

CONCLUSION

These findings highlight the critical importance of early diagnosis, optimized antibiotic therapy, and careful monitoring to reduce complications and improve survival outcomes in neonates with SA pneumonia.

Epidemiology and Mortality of Invasive Staphylococcus aureus Infections in Hospitalized Infants

Importance

Historically, Staphylococcus aureus has been a leading cause of morbidity and mortality in the neonatal intensive care unit (NICU). The current incidence and attributable mortality of late-onset invasive S aureus infection in hospitalized infants is unknown.

Objective

To estimate the incidence and attributable mortality of late-onset S aureus infection among hospitalized infants in the US.

Design, Setting, and Participants

This retrospective cohort study included an emulated trial among a national convenience sample of 315 NICUs within the US between 2016 and 2021. Participants were infants aged at least 4 postnatal days who were hospitalized in a participating NICU. Data were analyzed from May to August 2024.

Exposures

The primary exposures were birth weight and postnatal age.

Main Outcomes and Measures

The outcomes were the incidence and attributable mortality of late-onset invasive S aureus infection. Methicillin-resistant and methicillin-sensitive S aureus classification was not universally available; thus, all invasive S aureus infections were pooled.

Results

From 468 201 infants (260 491 [55.6%] male; median [IQR] gestational age, 36 [33-38] weeks) eligible for analysis, 1724 infants experienced 1762 infections for an overall incidence of 37.6 (95% CI, 35.9-39.4) invasive S aureus infections per 10 000 infants. Most infants with invasive infections were 32 weeks' gestational age or younger (1394 infants [80.9%]), very low birth weight (VLBW; ie, <1500 g) (1318 infants [76.5%]), and/or had a central line during their hospital stay (1509 infants [87.5%]). Invasive infections mostly included bloodstream infections (1505 infections [85.4%]), and 1160 infections (65.8%) occurred within 4 to 28 postnatal days. Birth weight inversely correlated with incidence: infants with VLBW experienced a more than 20-fold higher incidence relative to infants born weighing at least 1500 g (227.1 [95% CI, 215.3-239.4] vs 10.1 [95% CI, 9.1-11.1] infections per 10 000 infants). Most deaths following invasive infection occurred among VLBW infants (189 of 209 deaths [90.4%]). Compared with matched infants without a late-onset invasive S aureus infection, infected infants had an absolute difference in mortality rate of 5.3% (95% CI, 3.8%-6.8%).

Conclusions and Relevance

This cohort study found late-onset invasive S aureus infection and subsequent attributable mortality disproportionally affected infants with VLBW. Targeted infection prevention and control measures are necessary to reduce morbidity and mortality from invasive S aureus infections in this vulnerable population.

Efficacy of Enhanced Environmental Cleaning/Disinfection Using Pulsed Xenon Ultraviolet Light in Preventing Outbreaks of Methicillin-Resistant Staphylococcus aureus in Neonatal Intensive Care Units

BACKGROUND/OBJECTIVES

In recent years, non-contact room disinfection devices using ultraviolet light and hydrogen peroxide have emerged as disinfection methods. However, data on their usefulness in neonatal intensive care units (NICUs) are limited. Therefore, the aim of the present study was to evaluate the effectiveness of environmental disinfection in controlling methicillin-resistant Staphylococcus aureus (MRSA) outbreaks in a NICU/growing care unit (GCU).

METHODS

Daily cleaning/disinfection of the patient environment was changed from using a cloth containing quaternary ammonium salts to an agent containing ethanol and surfactant, and terminal cleaning with a pulsed xenon ultraviolet light (PX-UV) non-contact disinfection device was added for patients with confirmed MRSA and those on contact precautions. MRSA incidence and environmental culture results were then compared before and after the method change.

RESULTS

The MRSA infection rate was 2.81/1000 patient days before the method change and 0.90/1000 patient days after the change (p = 0.008). Environmental cultures were positive in 12/137 (8.8%) before the change and 0 after the change. There were no adverse events in the neonates due to PX-UV irradiation of the environment.

CONCLUSIONS

Daily cleaning and disinfection with ethanol and surfactant-containing cleaning disinfectants and a final cleaning with a PX-UV non-contact disinfection device reduced environmental MRSA contamination. In addition to adherence to hand hygiene and contact precautions, reducing MRSA present in the environment may contribute to MRSA control in NICUs and GCUs.

Exonuclease-III Assisted the Target Recycling Coupling with Hybridization Chain Reaction for Sensitive mecA Gene Analysis by Using PGM

In the field of neonatal infections nursing, methicillin-resistant Staphylococcus aureus (MRSA) is a major bacterial pathogen. Here, we present a portable biosensor for MRSA detection that is both highly sensitive and portable, owing to its implementation on the personal glucose meter (PGM) platform. The H probe was fixed on the magnetic bead for mecA gene analysis. A blunt 3' terminus appeared in the MBs-H probe when the mecA gene was present. Exonuclease-III (Exo-III) recognized the blunt terminus and cleaved it, freeing the mecA gene and so facilitating target recycling. In the meantime, the remaining H probe-initiated hybridization chain reaction (HCR) led to the desired signal amplification. Portable quantitative detection of mecA gene is possible because PGM can read the quantity of invertase tagged on HCR product. After optimizing several experimental parameters, such as the concentration of Exo-III and incubation time, the constructed sensor is extremely sensitive, with a detection limit of 2 CFU/mL. The results from this sensitive PGM-based sensor are in agreement with those obtained from plate counting methods, suggesting that it can be used to accurately assess the MRSA content in artificial clinical samples. In addition, the PGM sensor can significantly cut down on time spent compared to plate counting techniques. The manufactured sensor provides a promising option for accurate identification of pathogenic bacteria.

Epidemiological and microbiological characteristics of S. aureus pediatric infections in Colombia 2018-2021, a national multicenter study (Staphylored Colombia)

Background

Staphylococcus aureus infections are a significant cause of morbidity and mortality in pediatric populations worldwide. The Staphylo Research Network conducted an extensive study on pediatric patients across Colombia from 2018 to 2021. The aim of this study was to describe the epidemiological and microbiological characteristics of S. aureus in this patient group.

Methods

We analyzed S. aureus isolates from WHONET-reporting centers. An "event" was a positive culture isolation in a previously negative individual after 2 weeks. We studied center characteristics, age distribution, infection type, and antibiotic susceptibilities, comparing methicillin sensitive (MSSA) and resistant S. aureus (MRSA) isolates.

Results

Isolates from 20 centers across 7 Colombian cities were included. Most centers (80%) served both adults and children, with 55% offering oncology services and 85% having a PICU. We registered 8,157 S. aureus culture isolations from 5,384 events (3,345 MSSA and 1,961 MRSA) in 4,821 patients, with a median age of 5 years. Blood (26.2%) and skin/soft tissue (18.6%) were the most common infection sources. Most isolates per event remained susceptible to oxacillin (63.2%), clindamycin (94.3%), and TMP-SMX (98.3%). MRSA prevalence varied by city (<0.001), with slightly higher rates observed in exclusively pediatric hospitals. In contrast, the MRSA rate was somewhat lower in centers with Antimicrobial Stewardship Program (ASP). MRSA was predominantly isolated from osteoarticular infections and multiple foci, while MSSA was more frequently associated with recurrent infections compared to MRSA.

Conclusions

This is the largest study of pediatric S. aureus infections in Colombia. We found MSSA predominance, but resistance have important regional variations. S. aureus remains susceptible to other commonly used antibiotics such as TMP-SMX and clindamycin. Ongoing monitoring of S. aureus infections is vital for understanding their behavior in children. Prospective studies within the Staphylored LATAM are underway for a more comprehensive clinical and genetic characterization.

A decade of neonatal sepsis in Stockholm, Sweden: Gram-positive pathogens were four times as common as Gram-negatives

PURPOSE

To assess Gram-positive bacterial (GPB) bloodstream infection (BSI) in neonates, covering incidence, morbidity, mortality, antimicrobial resistance patterns and biomarkers in Region Stockholm, Sweden between 2006 and 2016.

METHODS

A population-based retrospective epidemiological study including infants with GPB-BSI, admitted to the neonatal units at Karolinska University Hospital (KUH). Data were collected from patient records, the Swedish Neonatal Quality Register, the microbiological laboratory at KUH and the Swedish Public Health Agency.

RESULTS

We identified 357 infants with GPB-BSI, representing an incidence of 1.47/1000 live births (LB). Group B streptococcus (GBS) was the most common pathogen causing BSI in full-term infants and early-onset sepsis (EOS) (0.20/1000 LB), while coagulase-negative staphylococci (CoNS) were predominant in infants born very preterm and in late-onset sepsis (LOS) (0.79/1000 LB). There were no fatal GBS BSI cases, but 10.2% developed meningitis. The GPB case fatality rate was 9.5% and the sepsis fatality rate 2.8%. In GPB-BSI, 1/10 did not have an elevated C-reactive protein level. Staphylococcus aureus (S. aureus) BSI increased during the study period, but no methicillin or vancomycin resistant strains were found. The antimicrobial resistance (AMR) rate was highest in CoNS isolates.

CONCLUSION

GPB-BSI was four times more common than Gram-negative BSI in neonates but resulted in lower mortality rate. GBS was the most common pathogen in full-term infants and in EOS. CoNS was the most common pathogen in LOS and infants born very preterm, and the AMR rate was high in these isolates. The increasing trend of S. aureus BSI indicates a need of further investigation.

Surveillance on meticillin-sensitive Staphylococcus aureus colonization and infection in a neonatal intensive care unit

BACKGROUND

Meticillin-sensitive Staphylococcus aureus (MSSA) infection is a significant health concern in neonatal intensive care units (NICUs). Bacterial colonization increases the risk of subsequent infection, leading to morbidity and mortality.

AIM

To report the findings of a retrospective cohort study on the surveillance of MSSA colonization and infection in NICU patients.

METHODS

The weekly microbial surveillance results for MSSA colonization in the throat, nose, anus, and groin, as well as invasive and non-invasive MSSA infections, were analysed from November 2020 to June 2022. The MSSA infection and colonization risk were compared after adjustment for confounders by stepwise logistic regression analysis.

FINDINGS

Three hundred and eighty-three neonates were screened; 42.8% (N=164) were MSSA colonized. Significant risk factors for MSSA colonization were length of stay, vaginal delivery and extreme low gestational age <28 weeks (ELGAN) (all P<0.05). The surveillance detected 38 (9.9%) mild MSSA infections and 11 (2.9%) invasive MSSA infections. Neonatal colonization with MSSA is a major risk factor for MSSA infection overall (29.3% in colonized/infected vs 70.7% colonized/not-infected and 0.5% in not-colonized/infected vs 99.5% in not-colonized/not-infected infants) and invasive MSSA infections (6.1% in colonized/infected vs 93.9% in colonized/not-infected and 0.5% in non-colonized/infected vs 99.5% not-colonized/not-infected infants). Also, extreme low birth weight (<1000 g), ELGAN and invasive ventilation were significant risk factors for MSSA infections (all, P<0.05).

CONCLUSIONS

The link between postnatal MSSA colonization and subsequent MSSA infection offers possibilities for prevention. Additional research is needed to explore the association between vaginal birth and the pathogenesis of neonatal MSSA colonization.