Clinical outcomes in methicillin-resistant Staphylococcus aureus-colonized neonates in the neonatal intensive care unit

Severe cellulitis from methicillin-resistant Staphylococcus aureus (MRSA) in a couple of preterm twins: a case report

BACKGROUND

Preterms are at risk of systemic infections as the barrier function of their immature skin is insufficient. The long period of hospitalization and the huge number of invasive procedures represent a risk factor for complications. Among the nosocomial infections of the skin, methicillin-resistant Staphylococcus aureus (MRSA) is associated with significant morbidity and mortality. We report a clinical case of cellulitis and abscess in two preterm twins caused by MRSA in a tertiary level Neonatal Intensive Care Unit (NICU).

CASE PRESENTATION

Two preterm female babies developed cellulitis from MRSA within the first month of extrauterine life. The first one (BW 990 g) showed signs of clinical instability 4 days before the detection of a hyperaemic and painful mass on the thorax. The second one (BW 1240 g) showed signs of clinical instability contextually to the detection of an erythematous, oedematous and painful area in the right submandibular space. In both cases the diagnosis of cellulitis was confirmed by ultrasound. A broad spectrum, multidrug antimicrobial therapy was administered till complete resolution.

CONCLUSIONS

Due to the characteristic antibiotic resistance of MRSA and the potential complications of those infections in such delicate patients, basic prevention measures still represent the key to avoid the spreading of neonatal MRSA infections in NICUs, which include hand hygiene and strict precautions, as well as screening of patients for MRSA on admission and during hospital stay, routine prophylactic topical antibiotic of patients, enhanced environmental cleaning, cohorting and isolation of positive patients, barrier precautions, avoidance of ward crowding, and, in some units, surveillance, education and decolonization of healthcare workers and visiting parents.

The Potential Threat of Vertical Transmission in Methicillin-Resistant Staphylococcus Aureus Infection: A Systematic Review 2022

This systematic review paper aimed to assess and analyze the prevalence of maternal colonization of Staphylococcus aureus (S. aureus) also known as methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) in the peripartum period and its significance on vertical transmission to the neonate and if it is a potential threat to the health of newborns. For this, multiple databases, such as PubMed, MEDLINE, ScienceDirect, and the database of Elsevier, were used to scout for relevant articles, and results were reported adhering to the principles set by Preferred Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines 2020. A specific medical subject headings (MeSH) criterion was designed to search for relevant publications on PubMed. A total of 26 articles were finally selected after a meticulous screening process, including detailed inclusion and exclusion criteria, manual reading of titles and abstracts, and availability of accessible full-text articles. A few articles were also selected after going through the citations section of the initially selected papers. Quality appraisal was done on the selected publications. Maternal colonization of S. aureus is determined to be highly prevalent with the hypothesis that nasal colonization had higher rates than recto-vaginal sites. Increasing maternal age, history of vaginitis, and multiparity were the most common risk factors for MRSA and MSSA colonization. Premature babies were at the highest risk of MRSA colonization. Breast milk is also a risk factor for neonatal MRSA transmission. Through this systematic review, we concluded that although the rate of vertical transmission of MRSA is lower than that of MSSA, we felt that it held significance as neonates with the bug have poor outcomes due to skin and soft tissue infections and there is spread of MRSA to other neonates in the wards and spread to siblings in cases of triplets and quadruplets and even death due to potential MRSA sepsis. Women in Africa and China had high prevalence rates of MRSA and S. aureus which can probably be attributed to a lack of access to adequate healthcare facilities. We recommend screening with regular recto-vaginal swabs and nasal swabs especially in regions with a high burden of MRSA to be performed at regular intervals after confirmation of pregnancy, as prevention and screening are effective to avoid serious complications.

Prevalence and clinical impact of methicillin-resistant Staphylococcus aureus colonization among infants at a level III neonatal intensive care unit

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is a well-known nosocomial pathogen in neonatal intensive care unit (NICU) patients. Studies on the impact of MRSA colonization on neonatal morbidities are scarce.

METHODS

We conducted a 1:3 matched cohort study among infants with and without MRSA colonization, born between January 2010 and June 2014, in a tertiary NICU to review their demographic characteristics and outcomes.

RESULTS

During the study period, rates of MRSA colonization and bacteremia were found to be 0.68% and 0.10%, respectively. No differences in demographic characteristics, mortality, and major morbidities were identified among infants with and without MRSA colonization.

CONCLUSIONS

We reported a low rate of MRSA colonization in infants admitted to our NICU, without impact on mortality and inhospital morbidity. Further large-scale studies are needed to understand the implications and cost-effectiveness of active MRSA surveillance.

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.

Infant Colonization With Methicillin-Resistant Staphylococcus aureus or Vancomycin-Resistant Enterococci Preceding Neonatal Intensive Care Unit Discharge

Rates of colonization with methicillin-resistant Staphylococcus aureus (MRSA) and/or vancomycin-resistant enterococci (VRE) were determined for 1320 infants within 7 days of neonatal intensive care unit discharge. Overall, 4% and 1% of the infants were colonized with MRSA or VRE, respectively. Predictors identified in fixed-effects models were surgery during hospitalization (for MRSA colonization) and prolonged antimicrobial treatment (for VRE colonization).

Regional Epidemiology of Methicillin-Resistant Staphylococcus aureus Among Critically Ill Children in a State With Mandated Active Surveillance

BACKGROUND

In theory, active surveillance of methicillin-resistant Staphylococcus aureus (MRSA) reduces MRSA spread by identifying all MRSA-colonized patients and placing them under contact precautions. In October 2007, Illinois mandated active MRSA surveillance in all intensive care units, including neonatal intensive care units (NICUs) and pediatric intensive care units (PICUs). We evaluated MRSA trends in a large metropolitan region in the wake of this law.

METHODS

Chicago hospitals with a NICU or PICU were recruited for 8 single-day point prevalence surveys that occurred twice-yearly between June 2008 and July 2011 and then yearly in 2012 to 2013. Samples from all patients were cultured for MRSA (nose and umbilicus for neonates, nose and groin for pediatric patients). Hospital-reported admission MRSA-screening results also were obtained. Point prevalence cultures were screened for MRSA by using broth enrichment, chromogenic agar, and standard confirmatory methods.

RESULTS

All eligible hospitals (N = 10) participated (10 NICUs, 6 PICUs). Hospital-reported adherence to state-mandated MRSA screening at admission was high (95% for NICUs, 94% for PICUs). From serial point prevalence surveys, overall MRSA prevalences in the NICUs and PICUs were 4.2% (89 of 2101) and 5.7% (36 of 632), respectively. MRSA colonization prevalences were unchanged in the NICUs (year-over-year risk ratio [RR], 0.93 [95% confidence interval (CI), 0.78-1.12]; P = .45) and trended toward an increase in the PICUs (RR, 1.25 [95% CI, 0.72-2.12]; P = .053). We estimated that 81% and 40% of MRSA-positive patients in the NICUs and PICUs, respectively, had newly acquired MRSA.

CONCLUSIONS

In a region with mandated active MRSA surveillance, we found ongoing unchanged rates of MRSA colonization and acquisition among NICU and PICU patients.

Epidemiology of Methicillin-Susceptible Staphylococcus aureus in a Neonatology Ward

OBJECTIVE

In-hospital transmission of methicillin-susceptible Staphylococcus aureus (MSSA) among neonates remains enigmatic. We describe the epidemiology of MSSA colonization and infection in a 30-bed neonatal ward.

DESIGN

Multimodal outbreak investigation

SETTING

A public 800-bed tertiary care university hospital in Switzerland

METHODS

Investigations in 2012-2013, triggered by a MSSA infection cluster, included prospective MSSA infection surveillance, microbiologic screening of neonates and environment, onsite observations, and a prospective cohort study. MSSA isolates were characterized by pulsed-field gel electrophoresis (PFGE) and selected isolates were examined for multilocus sequence type (MLST) and virulence factors.

RESULTS

Among 726 in 2012, 30 (4.1%) patients suffered from MSSA infections including 8 (1.1%) with bacteremia. Among 655 admissions in 2013, 13 (2.0%) suffered from MSSA infections including 2 (0.3%) with bacteremia. Among 177 neonates screened for S. aureus carriage, overall 77 (44%) tested positive. A predominant PFGE-1-ST30 strain was identified in 6 of 30 infected neonates (20%) and 30 of 77 colonized neonates (39%). This persistent clone was pvl-negative, tst-positive and belonged to agr group III. We found no environmental point source. MSSA carriage was associated with central vascular catheter use but not with a particular midwife, nurse, physician, or isolette. Observed healthcare worker behavior may have propagated transmission via hands and fomites. Despite multimodal interventions, clonal transmission and colonization continued and another clone, PFGE-6-ST5, became predominant.

CONCLUSIONS

Hospital-acquired MSSA clones represent a high proportion of MSSA colonization but not MSSA infections in neonate inpatients. In contrast to persisting MSSA, transmission infection rates decreased concurrently with interventions. It remains to be established whether eradication of hospital-acquired MSSA strains would reduce infection rates further.

[Update on outbreaks reported from neonatal intensive care units (2010-203): Staphylococcus aureus]

In terms of the unique risk profile of the patients and the morbidity associated with S. aureus infections in this vulnerable patient population, the literature on outbreaks of S. aureus (including MRSA) in neonatal intensive care units (NICUs) needs to be analyzed separately from reports derived from other intensive care units. With the objective of updating important information for those involved in outbreak management and fostering preventive efforts, this article summarizes the results of a systematic literature analysis, referring to an earlier publication by Gastmeier et al. It focuses on NICU outbreaks caused by S. aureus (including MRSA) and on controlling them.

Universal Admission Screening for Methicillin-Resistant Staphylococcus aureus in a Level HID Neonatal Intensive Care Unit: The First 9 Months

In response to epidemic methicillin-resistant Staphylococcus aureus (MRSA) in the community, the Illinois General Assembly mandated that all patients admitted to intensive care units statewide be screened for MRSA. Screening was instituted at our neonatal intensive care unit (NICU) in September 2007 by a polymerase chain reaction (PCR)-based strategy. The law created an opportunity to determine the rate of MRSA colonization among neonates, to gather information about subsequent MRSA infections, and to evaluate risk factors for MRSA colonization on admission to the NICU.

Active Surveillance and Decolonization of Methicillin-Resistant Staphylococcus aureus on Admission to Neonatal Intensive Care Units in Hong Kong: A Cost-Effectiveness Analysis

Objective.

To examine potential clinical outcomes and cost of active methicillin-resistant Staphylococcus aureus (MRSA) surveillance with and without decolonization in neonatal intensive care units (NICUs) from the perspective of healthcare providers in Hong Kong.

Design.

Decision analysis modeling.

Setting.

NICU.

Patients.

Hypothetical cohort of patients admitted to an NICU.

Methods.

We designed a decision tree to simulate potential outcomes of active MRSA surveillance with and without decolonization in patients admitted to an NICU. Outcome measures included total direct medical cost per patient, MRSA infection rate, and MRSA-associated mortality rate. Model inputs were derived from the literature. Sensitivity analyses evaluated the impact of uncertainty in all model variables.

Results.

In the base-case analysis, active surveillance plus decolonization showed a lower expected MRSA infection rate (0.911% vs 1.759%), MRSA-associated mortality rate (0.223% vs 0.431%), and total cost per patient (USD 47,294 vs USD 48,031) compared with active surveillance alone. Sensitivity analyses showed that active surveillance plus decolonization cost less and had lower event rates if the incidence risk ratio of acquiring MRSA infections in carriers after decolonization was less than 0.997. In 10,000 Monte Carlo simulations, active surveillance plus decolonization was significantly less costly than active surveillance alone 99.9% of the time, and both the MRSA infection rate and the MRSA-associated mortality rate were significantly lower 99.9% of the time.

Conclusions.

Active surveillance plus decolonization for patients admitted to NICUs appears to be cost saving and effective in reducing the MRSA infection rate and the MRSA-associated mortality rate if addition of decolonization to active surveillance reduces the risk of MRSA infection.

Infect Control Hosp Epidemiol 2012;33(10):1024-1030

Clinical and molecular characteristics of community-acquired methicillin-resistant Staphylococcus aureus infections in Chinese neonates

This study aims to characterize the clinical features of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in Chinese neonates, as well as the molecular characteristics and expression of key virulence genes of isolates. Clinical information and molecular characteristics of 130 cases were analyzed. Up to 83.8% patients were affected with late-onset infection. Cesarean delivery was the main delivery route, accounting for 74.6% of the total deliveries. Pneumonia (69, 53.1%) was the most common infection. A total of 38 patients (29.2%) suffered from complications. Moreover, 35 cases (26.9%) were invasive infections, among which 88.6% involved multiple organs and 45.7% suffered from complications. Cesarean section and premature birth were the risk factors for invasive CA-MRSA infection. ST59-MRSA-SCCmecIVa-t437 (54, 41.5%) was the most predominant CA-MRSA clone. The hla expression in the ST59 isolates was higher than that in ST910 (p = 0.02) and the hla expression in ST59-SCCmecV-t437 was higher than that in ST59-SCCmecIVa-t437. Approximately, 46.4% (13/28) of the infections caused by ST59-SCCmecV were invasive. This value is higher than that of ST59-SCCmecVa caused infections (14/59, 23.7%) (p = 0.03). This study showed that neonatal CA-MRSA infections in China readily become invasive, involve multiple organs, and are often accompanied by complications. The SCCmec V clone may be more pathogenic than the SCCmecVIa clone.

MRSA colonization and risk of infection in the neonatal and pediatric ICU: a meta-analysis

BACKGROUND AND OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of morbidity and mortality in NICUs and PICUs. Our objective was to assess the burden of MRSA colonization on admission, study the time trends, and examine the significance of MRSA colonization in this population.

METHODS

PubMed and Embase databases were consulted. Studies that reported prevalence of MRSA colonization on ICU admission were selected. Two authors independently extracted data on MRSA colonization and infection.

RESULTS

We identified 18 suitable articles and found an overall prevalence of MRSA colonization of 1.9% (95% confidence interval [CI] 1.3%-2.6%) on admission to the NICU or PICU, with a stable trend over the past 12 years. Interestingly, 5.8% (95% CI 1.9%-11.4%) of outborn neonates were colonized with MRSA on admission to NICU, compared with just 0.2% (95% CI 0.0%-0.9%) of inborn neonates (P = .01). The pooled acquisition rate of MRSA colonization was 4.1% (95% CI 1.2%-8.6%) during the NICU and PICU stay and was as high as 6.1% (95% CI 2.8%-10.6%) when the NICU population was studied alone. There was a relative risk of 24.2 (95% CI 8.9-66.0) for colonized patients to develop a MRSA infection during hospitalization.

CONCLUSIONS

In the NICU and PICU, there are carriers of MRSA on admission, and MRSA colonization in the NICU is almost exclusively associated with outborn neonates. Importantly, despite infection control measures, the acquisition rate is high, and patients colonized with MRSA on admission are more likely to suffer a MRSA infection during hospitalization.

Methicillin-resistant Staphylococcus aureus nasal colonization in a department of pediatrics: a cross-sectional study

BACKGROUND

We describe methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage at admission in patients admitted to a Department of Pediatrics.

METHODS

All patients received a nasal swab at admission. A questionnaire was administered and molecular genetics analyses were performed on all identified MRSA isolates.

RESULTS

We enrolled 785 patients, affected with both acute and chronic diseases. MRSA nasal colonization prevalence was 1.15% (CI: 0.5607%-2.093%). Methicillin-sensitive Staphylococcus aureus (MSSA) nasal colonization prevalence at admission was 19.75% (CI 17.07%-22.64%). Only one MRSA isolate carried the SCCmec V variant; all other isolates carried the SCCmecIV variant. Five out of 9 MRSA-colonized patients had an underlying condition. Antibiotic therapy in the previous 6 months was a protective factor for both MRSA (OR 0,66; 95% CI: 0,46-0,96) and MSSA (OR 0,65; 95% CI: 0,45-0,97) colonization. A tendency to statistical significance was seen in the association between hospitalization in the 6 months prior to admission and MRSA colonization at admission (OR 4,92; 95% CI: 0,97-24,83). No patient was diagnosed with an S. aureus infection during hospitalization.

CONCLUSIONS

The majority of our MRSA colonizing isolates have community origins. Nevertheless, most MRSA-colonized patients had been hospitalized previously, suggesting that strains that circulate in the community also circulate in hospital settings. Further studies should elucidate the role of children with frequent contact with health care institutions in the circulation of antibiotic resistant strains between the hospital and the community.

MRSA nasal colonization in children: prevalence meta-analysis, review of risk factors and molecular genetics

BACKGROUND

We report a meta-analysis of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization prevalence in children and a review of the risk factors as well as molecular genetic characterization.

METHODS

All relevant studies reporting prevalence data on MRSA nasal colonization in children published between January 2000 and August 2010 were retrieved from the MEDLINE database and analyzed.

RESULTS

After screening 544 studies, 50 studies were included. We obtained an estimate of MRSA prevalence of 2.7% (95% confidence interval [CI]: 2.2-3.1); of 5.2% (95% CI: 3.1-7.3) in children with underlying conditions and of 2.3% (95% CI: 1.8-2.7) in healthy children; 5.4% (95% CI: 3.1-7.7) in children recruited in hospitals and 3% (95% CI: 2.4-3.6) in children recruited in the community. Staphylococcal cassette chromosome mec type IV is the most diffused cassette globally.

CONCLUSION

The hospital remains the environment where the microorganism circulates most. Children with underlying conditions could act as vectors of microorganisms between the hospital and the community. MRSA prevention strategies should be tailored to each specific institution, taking into account the nosocomial prevalence of MRSA nasal colonization and infections, and the prevalence of nasal colonization in the community that refers to the specific health care center.

Atypical pneumonia linked to community-acquired staphylococcus aureus cross-transmission in the nursery

We report the observation of a necrotizing pneumonia due to methicillin-resistant Staphylococcus aureus harboring the Panton-Valentine leukocidin-encoding gene in a previously healthy neonate, with favorable clinical outcome in spite of extensive radiologic lesions. The case was linked to a cluster of 3 neonates colonized by Panton-Valentine leukocidin-producing, methicillin-resistant S. aureus through cross-transmission in the nursery, underlining the need to comply with standard infection control precautions in the maternity ward.

Relationship between maternal and neonatal Staphylococcus aureus colonization

OBJECTIVE

The study aimed to assess whether maternal colonization with Staphylococcus aureus during pregnancy or at delivery was associated with infant staphylococcal colonization.

METHODS

For this prospective cohort study, women were enrolled at 34 to 37 weeks of gestation between 2007 and 2009. Nasal and vaginal swabs for culture were obtained at enrollment; nasal swabs were obtained from women and their infants at delivery and 2- and 4-month postbirth visits. Logistic regression was used to determine whether maternal colonization affected infant colonization.

RESULTS

Overall, 476 and 471 mother-infant dyads had complete data for analysis at enrollment and delivery, respectively. Maternal methicillin-resistant S aureus (MRSA) colonization occurred in 10% to 17% of mothers, with the highest prevalence at enrollment. Infant MRSA colonization peaked at 2 months of age, with 20.9% of infants colonized. Maternal staphylococcal colonization at enrollment increased the odds of infant staphylococcal colonization at birth (odds ratio; 95% confidence interval: 4.8; 2.4-9.5), hospital discharge (2.6; 1.3-5.0), at 2 months of life (2.7; 1.6-4.3), and at 4 months of life (2.0; 1.1-3.5). Similar results were observed for maternal staphylococcal colonization at delivery. Fifty maternal-infant dyads had concurrent MRSA colonization: 76% shared isolates of the same pulsed-field type, and 30% shared USA300 isolates. Only 2 infants developed staphylococcal disease.

CONCLUSIONS

S aureus colonization (including MRSA) was extremely common in this cohort of maternal-infant pairs. Infants born to mothers with staphylococcal colonization were more likely to be colonized, and early postnatal acquisition appeared to be the primary mechanism.

Clinical and economic impact of methicillin-resistant Staphylococcus aureus colonization or infection on neonates in intensive care units

OBJECTIVE

The rising incidence and mortality of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection in children has become a great concern. This study aimed to determine the clinical and economic impact of MRSA colonization or infection on infants and to measure excess mortality, length of stay, and hospital charges attributable to MRSA.

DESIGN

This is a retrospective cohort study.

SETTING AND PATIENTS

The study included infants admitted to a level III-IV neonatal intensive care unit from September 1, 2004, through March 31, 2008.

METHODS

A time-dependent proportional hazard model was used to analyze the association between MRSA colonization or infection and mortality. The relationships between MRSA colonization or infection and length of stay and between MRSA colonization or infection and hospital charges were assessed using a matched cohort study design.

RESULTS

Of 2,280 infants, 191 (8.4%) had MRSA colonization or infection. Of 132 MRSA isolates with antibiotic susceptibility results, 106 were resistant to clindamycin and/or trimethoprim-sulfamethoxazole, thus representing a noncommunity phenotype. The mortality rate was 17.8% for patients with MRSA colonization or infection and 11.5% for control subjects. Neither MRSA colonization (hazard ratio [HR], 0.9 [95% confidence interval {CI}, 0.5-1.5]; P > .05 ) nor infection (HR, 1.2 [95% CI, 0.7-1.9]; P > .05 ) was associated with increased mortality risk. Infection caused by MRSA strains that were resistant to clindamycin and/or trimethoprim-sulfamethoxazole increased the mortality risk by 40% (HR, 1.4 [95% CI, 0.9-2.2]; P > .05 ), compared with the mortality risk of control subjects, but the increase was not statistically significant. MRSA infection independently increased length of stay by 40 days (95% CI, 34.2-45.6; P < .001) and was associated with an extra charge of $164,301 (95% CI, $158,712-$169,889; P < .001).

CONCLUSIONS

MRSA colonization or infection in infants is associated with significant morbidity and financial burden but is not independently associated with increased mortality.

Is isolation of outborn infants required at admission to the neonatal intensive care unit?

BACKGROUND

To measure the rate of colonization of outborn infants with methicillin-resistant Staphylococcus aureus (MRSA) to evaluate the need for Contact Precautions (including isolation) at the time of admission to the neonatal intensive care unit (NICU).

METHODS

All 239 consecutive infants referred from the neonatal units of other hospitals to a tertiary NICU in Al Ain, United Arab Emirates, between January 2000 and December 2007 were screened for MRSA colonization. Swabs from the ear, nose, rectum, axillae, and groin were obtained from each patient, and the rates of colonization were calculated retrospectively.

RESULTS

Some 72% of newborns were admitted to our NICU in the first week. Only 1 patient, admitted from Oman, grew MRSA from the ear swab (rate, 0.4%; 95% confidence interval = 0.01% approximately 2.3%).

CONCLUSION

This study from a tertiary NICU in a developing country shows that outborn infants are unlikely to harbor MRSA, and thus their routine admission in a single-bed isolation room is not justified. MRSA screening on admission has a very low yield and does not appear to be cost-effective. Contact Precautions should be reserved for those newborns transferred from general pediatric wards and those admitted from home.

Eradication of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit: which measures for which success?

BACKGROUND

Various strategies for controlling methicillin-resistant Staphylococcus aureus (MRSA) outbreaks in neonatal intensive care units (NICUs) have been tried, with varying levels of success. We report a MRSA outbreak occurring between April 2004 and August 2007 in a 24-bed NICU in a large university hospital. We describe the difficulties involved in implementing measures to control the MRSA outbreak and the possible contribution of each measure.

METHODS

Cases were defined as neonates with MRSA obtained from either clinical cultures or surveillance cultures (from the anterior nares). Systematic screening of neonates for colonization was performed only between February and December 2005. Successive control strategies included barrier precaution and isolation in individual rooms, mupirocine ointment for neonates and health care workers, cohort isolation, hand hygiene observation, and staff training.

RESULTS

During the routine surveillance culture period (February to December 2005; 48 weeks), 46 neonates were found to be positive for MRSA and were treated with mupirocin. After December 2005, the outbreak was controlled, but the ongoing spread was not eradicated; 9 sporadic MRSA cases were detected by clinical culture up to August 2007.

CONCLUSION

The widespread use of mupirocine in staff and patients did not control the outbreak and is not recommended. The later control appeared to coincide with increased hand hygiene audits and training for staff, along with appropriate cohort isolation of neonates and cohort nursing.

Outbreak of gram-positive bacterial keratitis associated with epidemic keratoconjunctivitis in neonates and infants

OBJECTIVES

To report the clinical characteristics of bacterial keratitis associated with epidemic keratoconjunctivitis (EKC) and to evaluate the risk factors for bacterial keratitis development in eyes with EKC.

METHODS

After 108 patients diagnosed as EKC were retrospectively reviewed, clinical characteristics and incidence of bacterial keratitis-associated EKC were described. To analyse the effect of steroid use and the methicillin-resistant Staphylococcus aureus (MRSA) colonization in conjunctiva on developing bacterial keratitis, HCU-stayed children (n=43) were divided into two groups: those with and those without bacterial keratitis. Other risk factors such as gestational age, duration of hospitalization, MRSA colonization rate of other sites, and interval between follow-ups were evaluated in neonates who stayed in a neonatal intensive care unit (NICU; n=29).

RESULTS

Eight out of nine bacterial keratitis developed in HCU-stayed children. All the eight cases of bacterial keratitis occurred in neonates and infants. MRSA keratitis was found in seven hospitalized infants. The incidence of bacterial keratitis was significantly higher in HCU-stayed children than in outpatients (P=0.03), although it never occurred in HCU-stayed adults. The culture-positive rate of MRSA in conjunctiva (P=0.047) and topical use of steroid (P=0.01) were significantly higher in HCU-stayed children who carried bacterial keratitis. The incidence of bacterial keratitis was significantly related with the longer interval of follow-up in early EKC period in NICU in patients (P=0.009).

CONCLUSIONS

Infants and neonates show high tendency of MRSA keratitis accompanied with EKC, especially if they were in HCU, applied topical steroid or followed with long interval.

Case report of methicillin-resistant Staphylococcus aureus (MRSA) mastitis with abscess formation in a breastfeeding woman

An afebrile woman with persistent nonhealing nipples and low-grade intermittent breast pain was diagnosed at 9 weeks postpartum with a methicillin-resistant Staphylococcus aureus infection of the left breast with abscess formation. Unilateral weaning allowed partial lactation to continue.