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

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.

Application of Octenidine into Nasal Vestibules Does Not Influence SARS-CoV-2 Detection via PCR or Antigen Test Methods

The targeted or universal decolonization of patients through octenidine for nasal treatment and antiseptic body wash for 3 to 5 days prior elective surgery has been implemented in several surgical disciplines in order to significantly reduce surgical site infections (SSIs) caused by Staphylococcus aureus carriage. However, as most healthcare facilities also screen patients on admission for pilot infection, it is imperative that a prophylactic nasal decolonization procedure not yield a false negative SARS-CoV-2 status in otherwise positive patients. We assessed the effect of a commercially available octenidine-containing nasal gel on two different screening methods-antigen (Ag) detection based on colloidal gold immunochromatography and RT-PCR-in a prospective-type accuracy pilot study in asymptomatic SARS-CoV-2-positive inpatients. All patients still showed a positive test result after using the octenidine-containing nasal gel for about 3 days; therefore, its application did not influence SARS-CoV-2 screening, which is of high clinical relevance. Of note is that Ag detection was less sensitive, regardless of the presence of octenidine. From an infection prevention perspective, these results favor octenidine-based decolonization strategies, even during seasonal SARS-CoV-2 periods. As only asymptomatic patients are considered for elective interventions, screening programs based on RT-PCR technology should be preferred.

[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.

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.

Clinical Evidence for the Use of Octenidine Dihydrochloride to Prevent Healthcare-Associated Infections and Decrease Staphylococcus aureus Carriage or Transmission-A Review

BACKGROUND

The antiseptic agent octenidine dihydrochloride (OCT) is used for skin preparation, for Staphylococcus aureus decolonization, and within bundles for the prevention of catheter-related or surgical site infections (SSIs). Here, we review the evidence for the effects of OCT from clinical studies.

METHODS

Review of studies published in the Medline, Scopus, and Cochrane databases until August 2022, performed in clinical settings and reporting on effects of OCT on S. aureus carriage/transmission, SSI prevention, and prevention of intensive care unit (ICU)-related or catheter-related bloodstream and insertion site infections.

RESULTS

We included 31 articles. The success of S. aureus decolonization with OCT-containing therapies ranged between 6 and 87%. Single studies demonstrated that OCT application led to a reduction in S. aureus infections, acquisition, and carriage. No study compared OCT for skin preparation before surgical interventions to other antiseptics. Weak evidence for the use of OCT for pre-operative washing was found in orthopedic and cardiac surgery, if combined with other topical measures. Mostly, studies did not demonstrate that daily OCT bathing reduced ICU-/catheter-related bloodstream infections with one exception.

CONCLUSIONS

There is a need to perform studies assessing the clinical use of OCT compared with other antiseptics with respect to its effectiveness to prevent nosocomial infections.

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.

Hanitsch L, Krüger R, K. Lindner A, S. Stegemann M, Nurjadi D. Skin Infections Due to Panton-Valentine Leukocidin-Producing S. Aureus

BACKGROUND

Panton-Valentine leukocidin (PVL)-producing Staphylococcus aureus (PVL-SA) strains are frequently associated with large, recurring abscesses in otherwise healthy young individuals. The typical clinical presentation and the recommended diagnostic evaluation and treatment are not widely known.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, with special attention to international recommendations.

RESULTS

PVL-SA can cause leukocytolysis and dermatonecrosis through specific cell-wall pore formation. Unlike other types of pyoderma, such conditions caused by PVL-SA have no particular site of predilection. In Germany, the PVL gene can be detected in 61.3% (252/411) of skin and soft tissue infections with S. aureus. Skin and soft tissue infections with PVL-SA recur three times as frequently as those due to PVL-negative S. aureus. They are diagnosed by S. aureus culture from wound swabs and combined nasal/pharyngeal swabs, along with PCR for gene detection. The acute treatment of the skin abscesses consists of drainage, followed by antimicrobial therapy if needed. Important secondary preventive measures include topical cleansing with mupirocin nasal ointment and whole-body washing with chlorhexidine or octenidine. The limited evidence (level IIb) concerning PVL-SA is mainly derived from nonrandomized cohort studies and experimental analyses.

CONCLUSION

PVL-SA skin infections are easily distinguished from other skin diseases with targeted history-taking and diagnostic evaluation.

Disruption of the Cytoplasmic Membrane Structure and Barrier Function Underlies the Potent Antiseptic Activity of Octenidine in Gram-Positive Bacteria

The antimicrobial killing mechanism of octenidine (OCT), a well-known antiseptic is poorly understood. We recently reported its interaction with Gram-negative bacteria by insertion of OCT into the outer and cytoplasmic membrane of Escherichia coli, resulting in a chaotic lipid rearrangement and rapid disruption of the cell envelope. Its action primarily disturbs the packing order of the hydrophobic moiety of a lipid, which consequently might result in a cascade of multiple effects at a cellular level. Here, we investigated OCT's impact on two different Gram-positive bacteria, Enterococcus hirae and Bacillus subtilis, and their respective model membranes. In accordance with our previous results, OCT induced membrane disorder in all investigated model systems. Electron and fluorescence microscopy clearly demonstrated changes in cellular structure and membrane integrity. These changes were accompanied by neutralization of the surface charge in both E. hirae and B. subtilis and membrane disturbances associated with permeabilization. Similar permeabilization and disordering of the lipid bilayer was also observed in model membranes. Furthermore, experiments performed on strongly versus partly anionic membranes showed that the lipid disordering effect induced by OCT is a result of maximized hydrophobic over electrostatic forces without distinct neutralization of the surface charge or discrimination between the lipid head groups. Indeed, mutants lacking specific lipid head groups were also susceptible to OCT to a similar extent as the wild type. The observed unspecific mode of action of OCT underlines its broad antimicrobial profile and renders the development of bacterial resistance to this molecule less likely. IMPORTANCE OCT is a well-established antiseptic molecule routinely used in a large field of clinical applications. Since the spread of antimicrobial resistance has restricted the use of antibiotics worldwide, topically applied antiseptics like OCT, with a broad spectrum of antimicrobial activity and high safety profile, gain increasing importance for effective infection prevention and therapy. To eliminate a wide spectrum of disease-causing microorganisms, a compound's antiseptic activity should be unspecific or multitarget. Our results demonstrate an unspecific mechanism of action for OCT, which remained largely unknown for years. OCT disturbs the barrier function of a bacterial cell, a function that is absolutely fundamental for survival. Because OCT does not distinguish between lipids, the building blocks of bacterial membranes, its mode of action might be attributed to all bacteria, including (multi)drug-resistant isolates. Our results underpin OCT's potent antiseptic activity for successful patient outcome.

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.

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.

Sepsis related mortality of extremely low gestational age newborns after the introduction of colonization screening for multi-drug resistant organisms

BACKGROUND

In 2013 German infection surveillance guidelines recommended weekly colonization screening for multidrug-resistant (MDRO) or highly epidemic organisms for neonatal intensive care units (NICUs) and extended hygiene measures based on screening results. It remains a matter of debate whether screening is worth the effort. We therefore aimed to evaluate sepsis related outcomes before and after the guideline update.

METHODS

The German Neonatal Network (GNN) is a prospective cohort study including data from extremely preterm infants between 22 + 0 and 28 + 6 gestational weeks born in 62 German level III NICUs.

RESULTS

Infants treated after guideline update (n = 8.903) had a lower mortality (12.5% vs. 13.8%, p = 0.036), reduced rates for clinical sepsis (31.4 vs. 42.8%, p <  0.001) and culture-proven sepsis (14.4% vs. 16.5%, p = 0.003) as compared to infants treated before update (n = 3.920). In a multivariate logistic regression analysis, nine pathogens of culture-proven sepsis were associated with sepsis-related death, e.g. Pseudomonas aeruginosa [OR 59 (19-180), p <  0.001)]. However, the guideline update had no significant effect on pathogen-specific case fatality, total sepsis-related mortality and culture-proven sepsis rates with MDRO. While the exposure of GNN infants to cefotaxime declined over time (31.1 vs. 40.1%, p <  0.001), the treatment rate with meropenem was increased (31.6 vs. 26.3%, p <  0.001).

CONCLUSIONS

The introduction of weekly screening and extended hygiene measures is associated with reduced sepsis rates, but has no effects on sepsis-related mortality and sepsis with screening-relevant pathogens. The high exposure rate to meropenem should be a target of antibiotic stewardship programs.

Anti-Acanthamoeba disinfection: hands, surfaces and wounds

Acanthamoebae are facultative parasites causing rare but serious infections such as keratitis and encephalitis and are also known as vectors for several bacterial pathogens, including legionellae and pseudomonads. Acanthamoeba cysts are particularly resilient and enable the amoebae to withstand desiccation and to resist disinfection and therapy. While the search for new therapeutic options has been intensified in the past years, hand and surface disinfectants as well as topical antiseptics for preventing infections have not been studied in detail to date. The aim of this study was to screen well-known and commonly used antimicrobial products in various formulations and different concentrations for their efficacy against Acanthamoeba trophozoites and cysts, including aliphatic alcohols, quaternary ammonium compounds (QACs), peracetic acid (PAA), potassium peroxymonosulfate sulfate (PPMS) and octenidine dihydrochloride (OCT). Of all products tested, OCT and QACs showed the highest efficacy, totally eradicating both trophozoites and cysts within 1 min. The determined 50% effective concentration (EC₅₀) for cysts was 0.196 mg/mL for OCT and 0.119 mg/mL for QACs after 1 min of exposure. PAA and PPMS showed reliable cysticidal efficacies only with prolonged incubation times of 30 min and 60 min, respectively. Aliphatic alcohols generally had limited efficacy, and only against trophozoites. In conclusion, OCT and QACs are potent actives against Acanthamoeba trophozoites and cysts at concentrations used in commercially available products, within contact times suitable for surface and hand disinfection as well as topical antisepsis.

Colonization Screening Targeting Multidrug-Resistant Gram-Negative Pathogens Does Not Increase the Use of Carbapenems in Very Low Birth Weight Infants

Since 2012, a colonization screening (CoS) for multidrug-resistant Gram-negative bacteria (MRGN) in very low birth weight infants (VLWBI) was implemented in order to provide a basis for an effective empiric therapy of subsequent nosocomial infections (NI). According to antibiotic stewardship, carbapenems should be reserved for NI caused by MRGN or severe NI. We examined whether the CoS increased the first-line use of carbapenems. In this retrospective cohort analysis, we enrolled all VLBWI before (2009-2011) and after (2012-2014) the introduction of CoS (2012) at a tertiary university neonatal intensive care and neonatal intermediate care unit (NIMC) in Germany. Rectal swabs were used to detect MRGN colonization (on admission and weekly until discharge from the NIMC). The use of carbapenems was measured by days of therapy (DoT). To exclude the replacement of carbapenems by other antibiotics, antibiotic therapy for late-onset sepsis (LOS) was assessed by DoT and length of therapy (LoT). In 55/201 (27.4%) VLBWI, CoS detected MRGN colonization. Compared to the cohort prior to the introduction of CoS (n = 191), a significant decrease in LoT (p < 0.001) and total DoT (p < 0.001) was seen (n = 201). This was due to a significant decrease in LoT (p < 0.001) and total DoT (p < 0.001) in the birth weight category of 1,000-1,499 g. In these infants, DoT for carbapenems (p = 0.009) was significantly lower, possibly caused by a significant decline of LOS (25 episodes vs. 39 episodes, p = 0.025). Conversely, no significant differences in LoT and total DoT were seen in infants with a birth weight <500 g (p = 1.000; p = 0.758) and in infants weighing 500-999 g (p = 0.754; p = 0.794). DoT for carbapenems was not significantly different in the total cohort after the introduction of CoS (p = 0.341). Prolonged exposure to carbapenems (in terms of DoT) significantly postponed the first detection of MRGN colonization (p = 0.023). The introduction of CoS did not result in an increased use of carbapenems. Concomitant carbapenem treatment may reduce the sensitivity of CoS relying on rectal swabs.

Alteration of antibiotic regimen as an additional control measure in suspected multi-drug-resistant Enterobacter cloacae outbreak in a neonatal intensive care unit

BACKGROUND

Increased occurrence of a particular species of Gram-negative bacteria (GNB), especially when multi-drug-resistant (MDR), in routine screening surveillance in neonatal intensive care units (NICUs) can be evoked by selection pressure.

AIM

To evaluate adaptation of the empiric antibiotic regimen for its usefulness as a control measure in suspected outbreaks in the NICU.

METHODS

In a retrospective outbreak analysis, cases between 1^st December 2017 and 31^st March 2018 were identified through microbiology and hygiene surveillance records. Furthermore, risk factors for MDR-GNB colonization were collected. Whole-genome sequencing (WGS) was performed on all isolates. Control measure documentations and interviews were employed to define interventions. As well as infection control measures, administration of third-generation cephalosporins was avoided and replaced whenever clinically acceptable as part of the intervention bundle.

FINDINGS

In total, nine patients were found to have rectal colonization with third-generation cephalosporin-resistant Enterobacter cloacae in routine screening surveillance in the pre-intervention period. After implementation of an infection control bundle, the incidence declined rapidly. WGS analysis revealed that two MDR E. cloacae were transmitted, and the majority were new cases. The incidence density of MDR-GNB colonization was 7.94/1000 patient-days (PD) before the intervention and 1.68/1000 PD during the altered antibiotic regimen. No infections with MDR-GNB occurred during the study.

CONCLUSIONS

Altering the antibiotic regimen with regard to selection pressure may be considered as part of an intervention bundle to rapidly control the emergence of MDR-GNB in suspected outbreak situations in the 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.

Evaluation of an 'all-in-one' seven-day whole-genome sequencing solution in the investigation of a Staphylococcus aureus outbreak in a neonatal intensive care unit

BACKGROUND

Meticillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA) are responsible for outbreaks in intensive care units. MSSA infections have the same morbidity and mortality rate as MRSA infections but are studied less often. Whole-genome sequencing (WGS) is used increasingly for outbreak monitoring, but still requires specific installation and trained personnel to obtain and analyse the data.

AIM

To evaluate the workflow and benefits of EpiSeq solution (bioMérieux, Marcy l'Etoile, France) in exploring the increased incidence of S. aureus bloodstream infections in a neonatal intensive care unit (NICU).

METHODS

Four S. aureus bacteraemia isolates and 27 colonization isolates obtained between January and July 2016 were submitted to the 'all in one solution' EpiSeq [WGS, quality data assessment, multi-locus sequence typing (MLST), spa typing, virulome and resistome characterization, and phylogenetic tree construction]. More in-depth analyses were performed (whole-genome MLST and whole-genome single nucleotide polymorphism (wgSNP)] with BioNumerics software (Applied Maths, Sint-Martens-Latem, Belgium).

FINDINGS

Nine different sequence types and 13 different spa types were found among the 31 isolates studied. Among those isolates, 11 (seven patients) were ST146 spa type t002, five (four patients) were ST30 and four (four patients) were ST398. The 11 ST146 isolates had a maximum of seven pairwise SNP differences.

CONCLUSION

Use of EpiSeq solution allowed fast demonstration of the polyclonal profile of the MSSA population in neonates, and enabled the suspicion of a global outbreak to be ruled out. However, wgSNP analysis showed the transmission and persistence of one sequence type for over six months in the NICU, and enabled the infection control team to adapt its response.

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.

New Threats from an Old Foe: Methicillin-Resistant Staphylococcus aureus Infections in Neonates

Methicillin-resistant Staphylococcus aureus (MRSA) is a ubiquitous human inhabitant and one of the important pathogens of neonatal infections. MRSA is associated with significant mortality and morbidity, especially in very immature preterm neonates. Moreover, MRSA may be implicated in adverse long-term neonatal outcomes, posing a substantial disease burden. Recent advances in molecular microbiology have shed light on the evolution of MRSA population structure and virulence factors, which may contribute to MRSA epidemic waves worldwide. Equipped with remarkable genetic flexibility, MRSA has successfully developed resistance to an extensive range of antibiotics including vancomycin, as well as antiseptics. In the face of these new challenges from MRSA, our armamentarium of anti-infective strategies is very limited and largely dependent on prevention measures. Active surveillance cultures followed by decolonization may be a promising approach to control MRSA infections, with its efficacy and safety in the specific population of neonates yet to be addressed by large multicenter studies.