Surveillance for Colonization, Transmission, and Infection With Methicillin-Susceptible Staphylococcus aureus in a Neonatal Intensive Care Unit

Staphylococcus aureus: A Review of the Pathogenesis and Virulence Mechanisms

Staphylococcus aureus is a formidable human pathogen responsible for infections ranging from superficial skin lesions to life-threatening systemic diseases. This review synthesizes current knowledge on its pathogenesis, emphasizing colonization dynamics, virulence mechanisms, biofilm formation, and antibiotic resistance. By analyzing studies from PubMed, Scopus, and Web of Science, we highlight the pathogen's adaptability, driven by surface adhesins (e.g., ClfB, SasG), secreted toxins (e.g., PVL, TSST-1), and metabolic flexibility in iron acquisition and amino acid utilization. Nasal, skin, and oropharyngeal colonization are reservoirs for invasive infections, with biofilm persistence and horizontal gene transfer exacerbating antimicrobial resistance, particularly in methicillin-resistant S. aureus (MRSA). The review underscores the clinical challenges of multidrug-resistant strains, including vancomycin resistance and decolonization strategies' failure to target single anatomical sites. Key discussions address host-microbiome interactions, immune evasion tactics, and the limitations of current therapies. Future directions advocate for novel anti-virulence therapies, multi-epitope vaccines, and AI-driven diagnostics to combat evolving resistance. Strengthening global surveillance and interdisciplinary collaboration is critical to mitigating the public health burden of S. aureus.

Prevalence, antibiogram, and risk factors of methicillin-resistant Staphylococcus aureus (MRSA) asymptomatic carriage in Africa: a systematic review and meta-analysis

BACKGROUND

MRSA represents a significant public health challenge, particularly in resource-constrained regions like Africa. A critical factor in its spread is the role of asymptomatic carriers, who not only facilitate transmission but also face a markedly higher risk of developing MRSA-related infections. Against this backdrop, the current meta-analysis provides a comprehensive evaluation of MRSA colonization rates, associated risk factors, and antibiotic resistance profiles across African populations.

METHODS

A comprehensive literature search was conducted across African Journals Online, African Index Medicus, PubMed, Scopus, Google Scholar, and Web of Science from January 1, 2014, to January 1, 2025. Eligible studies reported on MRSA colonization rates, associated risk factors, or antibiotic resistance patterns within African populations. Results were presented as pooled prevalence or risk ratios (RR) with 95% confidence intervals, employing a random-effects model in R software (meta package). A p-value of < 0.05 was considered statistically significant. The study followed the PRISMA guidelines throughout.

RESULTS

Sixty-nine studies with 23,484 participants from 16 African countries were included. Subgroup analyses identified Healthcare Workers and hospitalized patients as having the highest pooled prevalence at 13.6% and 12.9%, respectively. Conversely, lower prevalence rates were observed among healthy community residents and children, at 4.1% and 4.7%, respectively. Among HCWs, Egypt reported the highest MRSA colonization rate at 18.1%. Key risk factors for MRSA colonization include a history of hospitalization (RR: 2.2), prior antibiotic use (RR: 1.4), diabetes mellitus (RR: 4.4), HIV with CD4 < 200 cells/µL (RR: 2.8), invasive procedures (RR: 4.8), and being a nurse compared to a physician (RR: 1.8), all with p < 0.05. Antibiotic resistance of MRSA was low for linezolid (2.7%) and vancomycin (5.9%), but higher for mupirocin (10.7%), clindamycin (23.6%), and Trimethoprim/sulfamethoxazole (38.9%).

CONCLUSION

MRSA colonization is a significant public health challenge in Africa, particularly among healthcare workers and hospitalized patients. Implementing targeted interventions for these high-risk groups can effectively reduce MRSA transmission and overall infection burden. Continuous monitoring is essential, especially given the resistance to mupirocin, a key antibiotic used for MRSA decolonization.

Characterization of a novel lytic phage against methicillin resistance Staphylococcus aureus in Hainan island

Methicillin resistance Staphylococcus aureus (MRSA) is currently threatening global public health, and a similar issue was encountered in Hainan. For establishing a promising alternative therapeutic option, a phage with the capacity of lysing 18 out of 35 MRSA clinical isolates was recovered from domestic natural sources, which was termed as vB_SauP_L1 due to its morphology and genomic similarity with Rountreeviridae. Satisfactory proliferation rate and environmental tolerance were demonstrated by subsequent infectious properties tests and stability assessments. Sequencing revealed that its genome consisted of a linear double-stranded DNA of 17,114 bp, in which neither virulent nor resistant gene was detected, indicating its potential in MRSA prevention and treatment.

Epidemiology of Methicillin-resistant Staphylococcus aureus Colonization in Neonates within Neonatal Intensive Care Units: A Systematic Review and Meta-analysis

Introduction

Methicillin-resistant Staphylococcus aureus (MRSA) colonization in neonatal intensive care units (NICUs) is a significant global health concern, leading to severe infections, extended hospital stays, and substantial economic burdens on health-care systems. To develop effective infection control strategies, we need to fill existing gaps in our understanding of MRSA epidemiology in neonates. The aim of this systematic review is to provide an extensive analysis of the proportion of MRSA colonizations in NICUs.

Methods

We used a comprehensive search strategy across databases such as Medline, Embase, Global Health, Web of Science, and Global Index Medicus, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles were independently reviewed and selected based on a variety of criteria, including the inclusion of neonates tested for MRSA colonization during NICU stay, and the reporting of community-acquired and hospital-acquired MRSA (CA-MRSA and HA-MRSA) incidence levels. Exclusion criteria included studies outside NICUs, those focused on specific MRSA outbreaks or clinical infections, review studies, and those lacking abstracts or full texts. Five authors independently extracted data, which was summarized and checked for quality. Statistical analysis included a random-effects model to compute pooled proportions, stratification by geographical location, evaluation of heterogeneity, and examination of publication bias.

Results

Our systematic review evaluated 62 studies out of an initial 536 records identified. The majority of the selected studies were conducted in high-income countries, primarily in the United States. From these studies, we estimated a cumulative incidence rate of 7.2% for MRSA colonization in NICUs. When the source of MRSA was considered, CA-MRSA incidence was 2.7%, while HA-MRSA incidence was notably higher at 11%. A subgroup analysis showed geographical differences in the cumulative incidence of MRSA colonization in NICUs, with Brazil having the lowest incidence and Taiwan the highest. The proportion of HA-MRSA colonization also varied significantly by country, with South Korea reporting higher incidence rates than the United States. However, the differences in CA-MRSA colonization rates between countries and WHO regions were not statistically significant.

Conclusions

Our systematic review found a cumulative incidence of 7.2% for MRSA colonization in NICUs, with HA-MRSA (11%) being more prevalent than CA-MRSA (2.7%). Regional variations were detected, with Taiwan exhibiting the highest cumulative incidence and South Korea having both the highest CA-MRSA and HA-MRSA. These findings underline the substantial public health impact of MRSA, especially in NICUs, necessitating context-specific prevention and control strategies. Future research should strive to address these regional disparities and aspire to attain a more globally representative understanding of MRSA colonization rates.

Effects of Discontinuation of Weekly Surveillance Testing on Methicillin-Resistant Staphylococcus aureus in the NICU

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a major cause of serious morbidity and mortality in the neonatal intensive care unit (NICU). There is no clear consensus on infection control measures. Some approaches to MRSA colonization management may be burdensome with unclear benefits. The objective of this study was to determine if stopping weekly MRSA surveillance with active detection and contact isolation (ADI) was associated with a change in infection rate.

STUDY DESIGN

This is a retrospective cohort study of infants admitted to two affiliated NICUs. The ADI cohort infants received weekly nasal MRSA cultures and were placed in contact isolation if MRSA colonized for the duration of their hospitalization. The No Surveillance cohort infants were only placed in isolation if there was active MRSA infection or if MRSA colonization was identified incidentally. The rates of infection were determined between the cohorts.

RESULTS

There were 8,406 neonates representing 193,684 NICU days in the comparison period. In the ADI cohort, MRSA colonization occurred in 3.4% of infants and infection occurred in 29 infants (0.4%). There were no differences between cohorts in the percent of infants with a MRSA infection at any site (0.5 vs. 0.5%, p = 0.89), rate of MRSA infections per 1,000 patient-days (0.197 vs. 0.201, p = 0.92), rate of bloodstream infections (0.12 vs. 0.26%, p = 0.18), or in the overall mortality rate (3.7 vs. 3.0% p = 0.13). ADI represented an annual cost of $590,000.

CONCLUSION

The rates of MRSA infection did not change when weekly ADI was discontinued and was associated with a decrease in cost and resource utilization.

KEY POINTS

· Placing MRSA-colonized infants in contact isolation is a common practice.. · Data are limited with respect to efficacy in the NICU.. · This study provides evidence that active detection and contact isolation for MRSA colonization may not be beneficial..

Assessing the Concordance of MRSA Carriage Screening With MRSA Infections

OBJECTIVES

This study focused on children with confirmed methicillin-resistant Staphylococcus aureus (MRSA) infections to determine MRSA screening utility in guiding empirical anti-MRSA treatment of children without history of MRSA infection. We examined the concordance of screens to assess differences by infection type and used statistical analysis to determine significant contributors to concordance.

METHODS

Pediatric hospital patients admitted from 2002 through 2022 were included. Subjects had MRSA infections subsequent to MRSA surveillance screens performed the preceding year. Statistical analysis identified associations between MRSA screens and infections. Number needed to treat analysis calculated the utility of rescreening.

RESULTS

Among 246 subjects, 39.0% had concordant screens; 151 (61.4%) screens were obtained in the 2 weeks preceding infection. Sensitivity for bacteremia was 50.0% (n = 42), for endotracheal/respiratory 44.4% (n = 81), and 29.4% (n = 102) for skin and soft-tissue infection. For children aged younger than 6 months, sensitivity was 35.9% (n = 78). Multivariable analysis significantly associated days since screening with decreasing likelihood of concordance. Regression modeled the probability of concordance to drop below 50.0% for all infections after 4 days, after 6 days for bacteremia specifically, and 12 days for endotracheal/respiratory infections.

CONCLUSIONS

The concordance of screens was far lower than negative predictive values found previously; earlier studies were possibly impacted by low prevalence and exclusion of children at high risk to inform high negative predictive values. We suggest that negative MRSA screens should not invalidate reasonable suspicion for MRSA infection in patients with high pretest probabilities.

Perinatal colonization with extended-spectrum beta-lactamase-producing and carbapenem-resistant Gram-negative bacteria: a hospital-based cohort study

BACKGROUND

Antimicrobial resistance (AMR) is a growing global health threat that contributes to substantial neonatal mortality. Bangladesh has reported some of the highest rates of AMR among bacteria causing neonatal sepsis. As AMR colonization among newborns can predispose to infection with these bacteria, we aimed to characterize the frequency of and risk factors for colonization of mothers and newborns during hospitalization for delivery.

METHODS

We enrolled pregnant women presenting for delivery to a tertiary care hospital in Faridpur, Bangladesh. We collected vaginal and rectal swabs from mothers pre- and post-delivery, rectal swabs from newborns, and swabs from the hospital environment. Swabs were plated on agars selective for extended-spectrum-beta-lactamase producing bacteria (ESBL-PB) and carbapenem-resistant bacteria (CRB). We performed logistic regression to determine factors associated with ESBL-PB/CRB colonization.

RESULTS

We enrolled 177 women and their newborns during February-October 2020. Prior to delivery, 77% of mothers were colonized with ESBL-PB and 15% with CRB. 79% of women underwent cesarean deliveries (C-section). 98% of women received antibiotics. Following delivery, 98% of mothers and 89% of newborns were colonized with ESBL-PB and 89% of mothers and 72% of newborns with CRB. Of 290 environmental samples, 77% were positive for ESBL-PB and 69% for CRB. Maternal pre-delivery colonization was associated with hospitalization during pregnancy (RR for ESBL-PB 1.24, 95% CI 1.10-1.40; CRB 2.46, 95% CI 1.39-4.37). Maternal post-delivery and newborn colonization were associated with C-section (RR for maternal CRB 1.31, 95% CI 1.08-1.59; newborn ESBL-PB 1.34, 95% CI 1.09-1.64; newborn CRB 1.73, 95% CI 1.20-2.47).

CONCLUSIONS

In this study, we observed high rates of colonization with ESBL-PB/CRB among mothers and newborns, with pre-delivery colonization linked to prior healthcare exposure. Our results demonstrate this trend may be driven by intense use of antibiotics, frequent C-sections, and a contaminated hospital environment. These findings highlight that greater attention should be given to the use of perinatal antibiotics, improved surgical stewardship for C-sections, and infection prevention practices in healthcare settings to reduce the high prevalence of colonization with AMR organisms.

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.

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.

Preventing healthcare-associated MRSA bacteremia: getting to the root of the problem

Introduction

Bloodstream infections caused by methicillin-resistant Staphylococcus aureus (MRSA) remain a major challenge in most countries worldwide.

Setting

We describe a quasi-experimental sequential intervention at Mater Dei Hospital, Malta, to reduce hyper-prevalence of healthcare-associated MRSA bacteremia (HA-MRSA-B).

Interventions

The hospital initiated a hand hygiene (HH) campaign in 2008 to improve alcohol hand rub (AHR) use. In 2011, this was followed by root cause analysis (RCA) of all HA-MRSA-B cases and finally universal MRSA admission screening in 2014. Change-point analysis was used to evaluate the impact of the interventions.

Results

The effect of the HH campaign became evident when AHR consumption reached 40 L/1000 occupied bed days (BD). RCAs identified intravascular devices as the likely risk factor in 83% of all HA-MRSA-B; specifically non-tunneled double-lumen hemodialysis catheters (36%), peripheral venous cannulas (25%), and central venous catheters (22%). Interventions to improve their management resulted in the greatest reduction of HA-MRSA-B rates. They were informed by the RCA findings and targeted behavior change through education, motivation, and system change. Universal MRSA admission screening provided the final decline in incidence. Each intervention affected HA-MRSA-B rates after a lag period of approximately 18-24 months. Overall, HA-MRSA-B incidence decreased from 1.72 cases/10000BD in 2008 to 0.18/10000BD in 2019; a reduction of almost 90%. Intravenous device interventions were also associated with a reduction of methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia rates.

Conclusions

Significant improvement in HA-MRSA-B is possible, even in highly endemic regions. It requires well-planned behavior change interventions which are compatible with local context and culture.

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.

Monocentric observational cohort study to investigate the transmission of third-generation cephalosporin-resistant Enterobacterales in a neonatal intensive care unit in Heidelberg, Germany

Third-generation cephalosporin-resistant Enterobacterales is a major threat for newborns in neonatal intensive care units (NICUs). The route of acquisition in a non-outbreak setting should be investigated to implement adequate infection prevention measures. To identify risk factors for colonization with and to investigate the transmission pattern of third-generation cephalosporin-resistant Enterobacterales in a NICU setting. This monocentric observational cohort study in a tertiary NICU in Heidelberg, Germany, enrolled all hospitalized neonates screened for cephalosporin-resistant Enterobacterales. Data were collected from 1 January 2018 to 31 December 2021. Weekly screening by rectal swabs for colonization with third-generation cephalosporin-resistant Enterobacterales was performed for all newborns until discharge. Whole-genome sequencing was performed for molecular characterization and transmission analysis. In total, 1,287 newborns were enrolled. The median length of stay was 20 (range 1-250) days. Eighy-eight infants (6.8%) were colonized with third-generation cephalosporin-resistant Enterobacterales. Low birth weight [<1500 g (adjusted odds ratio, 5.1; 95% CI 2.2-11.5; P < 0.001)] and longer hospitalization [per 30 days (adjusted odds ratio, 1.7; 95% CI 1.5-2.0; P < 0.001)] were associated with colonization or infection with drug-resistant Enterobacterales in a multivariate analysis. Enterobacter cloacae complex was the most prevalent third-generation cephalosporin-resistant Enterobacterales detected, 64.8% (59 of 91). Whole-genome sequencing, performed for the available 85 of 91 isolates, indicated 12 transmission clusters involving 37 patients. This cohort study suggests that transmissions of third-generation cephalosporin-resistant Enterobacterales in newborns occur frequently in a non-outbreak NICU setting, highlighting the importance of surveillance and preventive measures in this vulnerable patient group. IMPORTANCE Preterm newborns are prone to infections. Therefore, infection prevention should be prioritized in this vulnerable patient group. However, outbreaks involving drug-resistant bacteria, such as third-generation resistant Enterobacterales, are often reported. Our study aims to investigate transmission and risk factors for acquiring third-generation cephalosporin-resistant Enterobacterales in a non-outbreak NICU setting. Our data indicated that premature birth and low birth weight are significant risk factors for colonization/infection with third-generation cephalosporin-resistant Enterobacterales. Furthermore, we could identify putative transmission clusters by whole-genome sequencing, highlighting the importance of preemptive measures to prevent infections in this patient collective.

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.

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.

A meta-analysis showing the effect of surgical site wound infections and associated risk factors in neonatal surgeries

A meta-analysis was performed to assess the effect of surgical site wound infections and risk factors in neonates undergoing surgery. A systematic literature search up to January 2022 incorporated 17 trials involving 645 neonates who underwent surgery at the beginning of the trial; 198 of them had surgical site wound infections, and 447 were control for neonates. The statistical tools like the dichotomous or continuous method used within a random or fixed-influence model to establish the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) to evaluate the risk factors and influence of surgical site wound infections in neonates undergoing surgery. Surgical site wound infections had significantly higher mortality with OR value 2.03 at 95% CI 1.40-2.95 with P-value <0.001, the longer length of hospital stay (MD, 31.88; 95% CI, 18.17-45.59, P < 0.001), and lower birthweight of neonates (MD, -0.30; 95% CI, -0.53 to -0.07, P = 0.01) compared with neonates with no surgical site wound infections undergoing surgery. However, no remarkable change was observed with surgical site wound infections in the gestational age at birth of neonates (MD, -0.70; 95% CI, -1.46 to 0.05, P = 0.07), and the preoperative antibiotic prophylaxis (OR, 1.28; 95% CI, 0.57-2.87, P = 0.55) compared with no surgical site wound infections for neonates undergoing surgery. Surgical site wound infections had significantly higher mortality, a longer length of hospital stay, and lower birthweight of neonates. However, they had no statistically significant difference in the gestational age at birth of neonates and the preoperative antibiotic prophylaxis compared with no surgical site wound infections for neonates undergoing surgery. Furthermore, evidence is needed to confirm the outcomes.

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.

Epidemiology and infection control of Methicillin-resistant Staphylococcus aureus in a German tertiary neonatal intensive and intermediate care unit: A retrospective study (2013-2020)

In preterm and term infants who require intermediate or intensive care Methicillin-resistant Staphylococcus aureus (MRSA) infection can lead to significant morbidity. In this study MRSA colonization and infection were assessed in a mixed tertiary neonatal intensive and intermediate care unit in Germany over an 8-year period (2013-2020). We investigated patient-related factors, associated with nosocomial MRSA acquisition, and we discuss our infection control concept for MRSA. Of 3488 patients treated during the study period, 24 were MRSA positive patients, corresponding to 26 patient hospital stays. The incidence was 0.7 MRSA patients per 100 patients. The incidence density was 0.4 MRSA patient hospital stays per 1000 patient days. Twelve patients (50%) acquired MRSA in the hospital. One patient developed a hospital acquired MRSA bloodstream infection 9 days after birth (i.e., 0.03% of all patients on the ward during the study period). A total of 122 patients had to be screened to detect one MRSA positive patient. In a logistic regression model, the use of 3rd generation intravenous cephalosporin (cefotaxim) was associated with nosocomial MRSA acquisition compared with matched control patients who did not acquire MRSA. In sum, the burden of MRSA colonization and infection in the ward was low during the study period. A comprehensive infection control concept that included microbiologic colonization screening, prospective infection surveillance together with isolation and emphasis on basic hygiene measures is essential to handle MRSA in this specialized setting.

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.

Whole-genome sequencing enhances existing pathogen and antimicrobial-resistance surveillance schemes within a neonatal unit

In some neonatal units, the screening of isolates for antimicrobial-resistant organisms is a matter of routine, with theoretical benefits including the prevention or early detection of outbreaks. This study sought to use whole-genome sequencing (WGS) retrospectively to characterize the genomic epidemiology of Gram-negative organisms obtained from a screening programme in a 32-bed unit providing intensive, high-dependency and special care at City Hospital, Birmingham, UK, identifying occult transmission events and clinically important antimicrobial-resistance (AMR) genes. WGS was performed for 155 isolates collected from rectal and umbilical screening swabs over a 2 month period from 44 individual neonates. Genomic epidemiological analysis showed possible transmission events involving Escherichia coli, Enterobacter cloacae, Klebsiella oxytoca and Klebsiella pneumoniae not detected by routine screening, with eight putative clusters involving different individuals identified. Within phylogenetic clusters, the relatedness of organisms – as determined by the abundance of SNPs – varied widely, indicating that a variety of transmission routes may be implicated. While clinically important AMR genes were not present in the putative transmission clusters, our observation of suspected interspecies horizontal transfer of bla_CTX-M-15 within individuals highlights the potential for their spread between organisms as well as individuals in this environment, with implications for surveillance. Our data show that WGS may reveal occult Gram-negative transmission events, demonstrating the potential of sequencing-based surveillance systems for nosocomial pathogens. Challenges remain in understanding how to utilize WGS surveillance to maximum effect in real-world settings.

Colonization of Extended-spectrum β-lactamase producing Enterobacterales and meticillin-resistant S. aureus in the intensive care unit at a tertiary hospital in Tanzania: Implications for Infection control and prevention

Background

Multi-drug resistant (MDR) bacteria pose a major global threat to public-health and are of particular concern to hospitalized intensive care unit (ICU) patients. This study aimed at addressing the burden of MDR and the associated factors at admission to ICU.

Methods

This was a cross-sectional study conducted at the ICU of a tertiary hospital in Tanzania. Rectal and anterior nares swabs were collected within 48 hours of ICU admission to screen for extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and meticillin-resistant Staphylococcus aureus (MRSA), respectively.

Results

The proportion of fecal carriage for ESBL-PE at admission to ICU was 54.54% (95% CI, 47.52–61.39), and nasal carriage for MRSA was 9.32% (95%CI, 5.67–14.93). The nasal MRSA colonization (OR = 1.52) and fecal carriage for ESBL-PE (OR=1.38) were more likely in participants who had received antibiotics before ICU admission than not, but association was not statistically significant. Hospitalization for ≥2 days (OR=1.18) was associated with fecal carriage of ESBL-PE, though not statistically significant. Overall, 66% and 73.5% of patients received antibiotics before and upon admission to ICU, respectively. Ceftriaxone, metronidazole and meropenem were commonly prescribed antibiotics. More than 84% of Enterobacterales were resistant to ciprofloxacin and trimethoprim-sulfamethoxazole, and 2.90% were resistant to meropenem. MRSA isolates showed a high rate of resistance to gentamicin and erythromycin.

Conclusion

MDR bacteria are common in patients admitted to ICU. To reduce the risk associated with MDR, we recommend use of simple screening methods to screen for MDR at ICU admission as part of infection control and prevention.

Utility of Methicillin-Resistant Staphylococcus aureus Nares Screening in Hospitalized Children with Acute Infectious Disease Syndromes

Studies in adults support the use of a negative methicillin-resistant Staphylococcus aureus (MRSA) nares screening (MNS) to help limit empiric anti-MRSA antibiotic therapy. We aimed to evaluate the use of MNS for anti-MRSA antibiotic de-escalation in hospitalized children (<18 years). Records of patients admitted between 1 January 2015 and 31 December 2020 with a presumed infectious diagnosis who were started on anti-MRSA antibiotics, had a PCR-based MNS, and a clinical culture performed were retrospectively reviewed. A total of 95 children were included with a median age (range) of 2 (0–17) years. The top three diagnosis groups were skin and soft tissue infections (n = 38, 40%), toxin-mediated syndromes (n = 17, 17.9%), and osteoarticular infections (n = 14, 14.7%). Nasal MRSA colonization and growth of MRSA in clinical cultures was found in seven patients (7.4%) each. The specificity and the negative predictive value (NPV) of the MNS to predict a clinical MRSA infection were both 95.5%. About half (n = 55, 57.9%) had anti-MRSA antibiotics discontinued in-house. A quarter (n = 14, 25.5%) were de-escalated based on the negative MNS test alone, and another third (n = 21, 38.2%) after negative MNS test and negative culture results became available. A high NPV suggests that MNS may be useful for limiting unnecessary anti-MRSA therapy and thereby a useful antimicrobial stewardship tool for hospitalized children. Prospective studies are needed to further characterize the utility of MNS for specific infectious diagnoses.