Candidemia Diagnosis With T2 Nuclear Magnetic Resonance in a PICU: A New Approach.

OBJECTIVES: Early diagnosis of invasive Candida infections is a challenge for pediatricians, intensivists, and microbiologists. To fill this gap, a new nanodiagnostic method has been developed using manual application of T2 nuclear magnetic resonance to detect Candida species. The aim of this study was to evaluate, prospectively, the usefulness as a tool diagnosis of the T2Candida panel in pediatric patients admitted at the PICU compared with blood culture. DESIGN: This is a prospective, observational, and unicentric study to compare T2Candida results with simultaneous blood cultures for candidemia diagnose. SETTING: This study was carried out in a 1,300-bed tertiary care hospital with a 16-bed medical-surgical PICU. PATIENTS: Sixty-three patients from 0 to 17 years old were enrolled in this study, including those undergoing solid organ transplantation (kidney, liver, pulmonary, multivisceral, intestinal, and heart) and hematopoietic stem cell transplantation. MEASUREMENTS AND MAIN RESULTS: Seven patients were positive by the T2Candida test. Only two of them had the simultaneous positive blood culture. T2Candida yielded more positive results than blood cultures. CONCLUSIONS: T2Candida might be useful for the diagnosis of candidemia in PICUs. The prevalence of candidemia might be underestimated in this pediatric population. The use of this diagnostic tool in these units may help clinicians to start adequate and timely antifungal treatments.

Carbapenem-Resistant Gram-Negative Bacterial Infections in Children.

Carbapenem-resistant organisms (CRO) are a major global public health threat. Enterobacterales hydrolyze almost all ß-lactams through carbapenemase production. Infections caused by CRO are challenging to treat due to the limited number of antimicrobial options. This leads to significant morbidity and mortality. Over the last few years, several new antibiotics effective against CRO have been approved. Some of them (e.g., plazomicin or imipenem-cilastatin-relebactam) are currently approved for use only by adults; others (e.g., ceftazidime-avibactam) have recently been approved for use by children. Recommendations for antibiotic therapy of CRO infections in pediatric patients are based on evidence mainly from adult studies. The availability of pediatric pharmacokinetic and safety data is the cornerstone to broaden the use of proposed agents in adults to the pediatric population. This article provides a comprehensive review of the current knowledge regarding infections caused by CRO with a focus on children, which includes epidemiology, risk factors, outcomes, and antimicrobial therapy management, with particular attention being given to new antibiotics.

Identifying priorities to improve paediatric in-hospital antimicrobial use by cross-sectional evaluation of prevalence and appropriateness of prescription.

INTRODUCTION: Information about paediatric in-hospital antimicrobial usage and prescribing patterns to guide improvement strategies is scant. We aim to use an evaluation of the prevalence and appropriateness of antimicrobial prescription to identify antimicrobial stewardship priorities in children. METHODS: A cross-sectional point study was performed on hospitalised paediatric patients in a Spanish tertiary hospital, assessing the prevalence of antimicrobial prescription (PAP) and appropriateness of antimicrobial prescription (AAP). AAP was defined as a correct indication plus an appropriate prescribing pattern (dose, spectrum and interval). Evaluation was performed using established antimicrobial guidelines. Other factors that may have a bearing on antimicrobial prescription were also analysed. RESULTS: A total of 171 patients were included. PAP was 49.7% (85/171) and AAP was 60.9% (91/161). The most common indications for antimicrobial use were antimicrobial prophylaxis (28.3%, 32/113) and pneumonia (8.2%, 8/113). Overall, 161 antimicrobials were prescribed (1.9 antimicrobials per patient): 55.3% (89/161) were empiric, 16.1% (26/161) were targeted and 28.6% (46/161) were prophylactic. Amoxicillin/clavulanate (8.2%, 14/171) and sulfamethoxazole/trimethoprim (8.2%, 14/171) were the most prescribed antimicrobials. The prescription of antifungals (11.7%, 20/171) and antivirals (1.8%, 3/171) was analysed. Major causes of inappropriate antibiotic use were prolonged prescriptions (21.7%, 35/161) and use of agents with an excessively broad coverage spectrum (21.1%, 34/161). PAP and AAP varied between wards and antimicrobials. CONCLUSIONS: Measurement of PAP and AAP offers valuable information for detecting priorities in hospital settings and monitoring antimicrobial usage prior to the development of antimicrobial stewardship programmes. In our setting, the main areas for improvement are duration of therapy and proper use of broad-spectrum antimicrobials.

Ceftazidime-Avibactam Use in a Case Series of Difficult-to-Treat or Recurrent Infections in Pediatric Patients with Complex Chronic Conditions: Effectiveness and Absence of Resistance Development.

The prevalence of multidrug-resistant Gram-negative infections, particularly carbapenem-resistant strains, has become a significant global health concern. Ceftazidime-avibactam (CZA) has emerged as a promising treatment option. However, data on its efficacy and safety in children are scarce, necessitating further investigation. We conducted a descriptive case series at a tertiary hospital in Spain from February 2019 to January 2022. Pediatric patients (<16 years) treated with CZA for confirmed or suspected multidrug-resistant Gram-negative infections were included. The clinical and microbiological characteristics, treatment approaches, and outcomes were examined. Eighteen children received CZA treatment. All had complex chronic conditions, with the most frequent underlying main diseases being liver transplantation (n = 8) and biliary atresia (n = 4). The predominant type of infection for which they received CZA was intra-abdominal infection caused or suspected to be caused by OXA-48-producing Klebsiella pneumoniae. CZA was generally well tolerated. Within the first month of starting CZA therapy, two patients died, with one case directly linked to the infection's fatal outcome. Some patients needed repeated courses of therapy due to recurrent infections, yet no resistance development was noted. In summary, the use of CZA showed effectiveness and safety, while the lack of resistance development highlights CZA's potential as a primary treatment option against OXA-48-producing infections.

Pneumonia in Children With Complex Chronic Conditions With Tracheostomy: An Emerging Challenge.

BACKGROUND: Despite respiratory infections being a leading cause of hospitalization in children with tracheostomy tubes, there are no published guidelines for their diagnosis and management. This study aims to outline the clinical, laboratory and microbiological aspects of pneumonia in these children, along with the antibiotics used and outcomes. Additionally, it seeks to determine pneumonia incidence and associated risk factors. METHODS: We conducted a retrospective study using the medical records of tracheostomized children at La Paz University Hospital in Madrid from 2010 to 2021. RESULTS: Thirty-three pneumonia cases were observed in 25 tracheostomized children. Pseudomonas aeruginosa was the predominant bacterium (52%), followed by Escherichia coli , Staphylococcus aureus and Serratia marcescens . The same microorganism isolated in the tracheal aspirate culture during pneumonia was previously isolated in 83% of cases that had a similar culture, with some growth obtained within 7-30 days prior. Multiplex respiratory PCR detected respiratory viruses in 73% of cases tested. Antibiotic treatment was administered in all cases except 1, mostly intravenously (81%), with piperacillin/tazobactam and meropenem being commonly used. Only 1 of the described episodes had a fatal outcome. CONCLUSIONS: It is advisable to include coverage for P. aeruginosa , E. coli , S. aureus , and S. marcescens in the empirical antibiotic treatment for pneumonia in tracheostomized children, along with the microorganisms identified in tracheal cultures obtained within 7-30 days prior, if available. A positive PCR for respiratory viruses is often discovered in bacterial pneumonia in tracheostomized children.

Duration of antibiotic therapy among paediatricians: A national survey of current clinical practice in Spain.

OBJECTIVES: Appropriate duration of antibiotic treatment is a key principle to reduce the emergence of bacterial resistance and antibiotic harm. The aim of this study was to document current clinical practice among Spanish paediatricians in terms of the duration of antibiotic therapy in both inpatient and outpatient settings, mapping the difference between practice and guidelines, and thus identifying opportunities to improve practice. METHODS: A national exploratory work survey was distributed in 2020 as a questionnaire about seven main infectious syndromes in children: genitourinary; skin and soft tissue; osteoarticular; ear, nose and throat; pneumonia; central nervous system; and bacteraemia. The answers were contrasted with current recommendations regarding the duration of antibiotic therapy. Demographic analysis was also performed. RESULTS: The survey was completed by 992 paediatricians in Spain, representing 9.5% of paediatricians working in the Spanish national health system. Hospital care clinicians accounted for 42.7% (6662/15590) of responses. The antibiotic duration used in practice was longer than recommended in 40.8% (6359/15590) of responses, and shorter than recommended in 16% (1705/10654) of responses. Only 25% (249/992) and 23% (229/992) of respondents indicated that they would prescribe antibiotics for the recommended treatment duration for lower urinary tract infection and community-acquired pneumonia (AI evidence). Among severe hospital-managed infections, a tendency towards longer courses of antibiotics was found for non-complicated meningococcal infections and non-complicated pneumococcal, Gram-negative and S. aureus bacteraemia. CONCLUSIONS: A noteworthy tendency towards prescribing antibiotics for longer than recommended among paediatricians was evidenced in this nationwide study, highlighting a wide range of opportunities for potential improvement.

Intestinal loads of extended-spectrum beta-lactamase and Carbapenemase genes in critically ill pediatric patients.

Introduction: Intestinal colonization by Multi-Drug Resistant Organisms (MDROs) can pose a threat on the health of critically ill patients. The extent of colonization by these organisms is related to previous antibiotic treatments and their ability to cause infections among adult patients. The aim of this study is to determine the relationship between the intestinal Relative Loads (RLs) of selected antibiotic resistance genes, antibiotic consumption and extra-intestinal spread among critically ill pediatric patients. Methods: RLs of bla CTX-M-1-Family, bla OXA-1, bla OXA-48 and bla VIM were determined in 382 rectal swabs obtained from 90 pediatric critically ill patients using qPCRs. The RLs were compared to the patients' demographics, antibiotic consumption, and detection of MDROs from extra-intestinal sites. 16SrDNA metagenomic sequencing was performed for 40 samples and clonality analyses were done for representative isolates. Results and discussion: 76 (74.45%) patients from which 340 (89.01%) rectal swabs were collected had at least one swab that was positive for one of the tested genes. Routine cultures did not identify carbapenemases in 32 (45.1%) and 78 (58.2%) swabs that were positive by PCR for bla OXA-48 and blaVIM, respectively. RLs of above 6.5% were associated with extra-intestinal spread of blaOXA-48-harboring MDROs. Consumption of carbapenems, non-carbapenem ß-lactams, and glycopeptides were statistically associated with testing negative for bla CTX-M-1-Family and bla OXA-1 while the consumption of trimethoprim/sulfamethoxazole and aminoglycosides was associated with testing negative for blaOXA-48 (P<0.05). In conclusion, targeted qPCRs can be used to determine the extent of intestinal dominance by antibiotic resistant opportunistic pathogens and their potential to cause extra-intestinal infections among a critically ill pediatric population.

Position statement of the Spanish Society of Paediatric Infectious Diseases on the introduction, implementation and assessment of antimicrobial stewardship programmes in paediatric hospitals.

In the past few years, antimicrobial resistance has increased, becoming a serious public health problem. The irrational use of antimicrobials is one of the main contributors to antimicrobial resistance. The paediatric population is not free from this problem, as antimicrobials are widely prescribed in this age group, often inappropriately. The introduction of antimicrobial stewardship programmes (ASPs) has proven crucial in curbing the emergence of antimicrobial resistance. At the international level, the need to develop specific paediatric ASPs has been recognised on account of the differences between adult and paediatric patients as concerns infection and approaches to diagnosis and treatment. For this reason, paediatric ASPs should be multidisciplinary programmes led by paediatric infectious disease specialists and use specific paediatric indicators (such as days of treatment, antimicrobial susceptibility patterns in the paediatric population, or clinical indicators) to help identify areas of improvement and develop effective targeted interventions. On the other hand, the support and leadership of the pertinent scientific societies are also essential. The purpose of this document is to present the position of the Sociedad Española de Infectología Pediátrica (SEIP, Spanish Society of Paediatric Infectious Diseases) concerning the implementation of paediatric ASPs in hospitals in Spain and to provide tools to facilitate their application in hospitals throughout the regional health care systems in the country.

Pregnancy Outcomes Among Perinatally HIV-Infected Women in Spain.

BACKGROUND: An increasing number of women living with perinatally acquired HIV are reaching adulthood and becoming pregnant. Achieving viral suppression is challenging in this population frequently exposed to numerous antiretroviral regimens. This study describes the long-term outcomes of pregnant women living with perinatally acquired HIV in Spain. METHODS: Descriptive, retrospective, multicenter study of the women living with perinatally acquired HIV who gave birth between January 2000 and December 2019 in Madrid. Epidemiological, clinical, and HIV-related data were collected from the first delivery to the end of the study period, including antiretroviral therapy, prevention strategies, and outcomes. RESULTS: Sixty-three live births in 33 women were included. The mean number of pregnancies per women was 1.9 (range: 1-6). At first delivery, women's median age was 20 years (interquartile range: 18-23), 11 (33.3%) had been previously diagnosed with AIDS and 6 (18%) with mental health disorders. Forty percent became pregnant unsuppressed, whereas 81% achieved viral suppression at delivery. Treatment interruptions were common after delivery, as were losses to follow-up, with no positive effect of pregnancy on retention to care or the immune virological situation. Five women (15%) experienced a new AIDS event, and there were 2 deaths (6%) during follow-up. There was 1 case of mother-to-child transmission in a nonadherent woman in whom preventive measures could not be implemented. CONCLUSIONS: Pregnancy in this unique population of women living with perinatally acquired HIV poses particular challenges. Specific strategies, including a multidisciplinary approach, are needed to minimize perinatal transmission risks and improve outcomes during the postpartum period.

Intestinal Dominance by Multidrug-Resistant Bacteria in Pediatric Liver Transplant Patients.

Pediatric liver transplantation (PLTx) is commonly associated with extensive antibiotic treatments that can produce gut microbiome alterations and open the way to dominance by multidrug-resistant organisms (MDROs). In this study, the relationship between intestinal Relative Loads (RLs) of ß-lactamase genes, antibiotic consumption, microbiome disruption, and the extraintestinal dissemination of MDROs among PLTx patients is investigated. 28 PLTx patients were included, from whom 169 rectal swabs were collected. Total DNA was extracted and blaCTX-M-1-Family, blaOXA-1, blaOXA-48, and blaVIM were quantified via quantitative polymerase chain reaction (qPCR) and normalized to the total bacterial load (16SrRNA) through LogΔΔCt to determine the RLs. 16SrRNA sequencing was performed for 18 samples, and metagenomic sequencing was performed for 2. Patients' clinical data were retrieved from the hospital's database. At least one of the genes tested were detected in all of the patients. The RLs for blaCTX-M-1-Family, blaOXA-1, blaOXA-48, and blaVIM were higher than 1% of the total bacterial population in 67 (80.73%), 56 (78.87%), 57 (77.03%) and 39 (61.9%) samples, respectively. High RLs for blaCTX-M-1-Family, blaOXA-1, and/or blaOXA-48, were positively associated with the consumption of carbapenems with trimethoprim-sulfamethoxazole and coincided with low diversity in the gut microbiome. Low RLs were associated with the consumption of noncarbapenem ß-lactams with aminoglycosides (P < 0.05). Extraintestinal isolates harboring the same gene(s) as those detected intraintestinally were found in 18 samples, and the RLs of the respective swabs were high. We demonstrated a relationship between the consumption of carbapenems with trimethoprim-sulfamethoxazole, intestinal dominance by MDROs and extraintestinal spread of these organisms among PLTx patients. IMPORTANCE In this study, we track the relative intestinal loads of antibiotic resistance genes among pediatric liver transplant patients and determine the relationship between this load, antibiotic consumption, and infections caused by antibiotic-resistant organisms. We demonstrate that the consumption of broad spectrum antibiotics increase this load and decrease the gut microbial diversity among these patients. Moreover, the high loads of resistance genes were related to the extraintestinal spread of multidrug-resistant organisms. Together, our data show that the tracking of the relative intestinal loads of antibiotic resistance genes can be used as a biomarker that has the potential to stop the extraintestinal spread of antibiotic-resistant bacteria via the measurement of the intestinal dominance of these organisms, thereby allowing for the application of preventive measures.

Nutritional Supplementation to Increase Influenza Vaccine Response in Children Living With HIV: A Pilot Clinical Trial.

Aims: Vaccine response is poor among children living with HIV. The gut microbiota has been identified as a potential target to improve vaccine immunogenicity, but data are scarce in the context of HIV infection. Methods: Pilot, double-blind, randomized placebo-controlled trial in which 24 HIV-infected children were randomized to receive a mixture of symbiotics, omega-3/6 fatty acids, and amino acids or placebo for 4 weeks, each in combination with ART, and were then immunized against influenza. Vaccine response and safety of the nutritional supplementation were the primary outcomes. Results: Eighteen HIV-infected children completed the follow-up period (mean age 11.5 ± 4.14 years, 61% female). The nutritional supplement was safe but did not enhance the response to the influenza vaccine. A 4-fold rise in antibody titers was obtained in only 37.5% of participants in the intervention arm vs. 40% in the placebo. No immunological or inflammatory predictors of vaccine response were identified. Conclusions: In this exploratory study, a 4-week course of symbiotics did not increase influenza vaccine immunogenicity in HIV-infected children. Larger studies are warranted to address the potential of modulating the microbiome in children living with HIV.

Risk factors for antibiotic-resistant bacteria colonisation in children with chronic complex conditions.

To assess drug-resistant bacterial colonisation rates and associated risk factors in children with complex chronic conditions admitted to a national reference unit in Spain. Cross-sectional study that included all children admitted to our unit from September 2018 to July 2019. Rectal swabs were obtained to determine multidrug-resistant Gram-negative bacilli (MR-GNB) colonisation, and nasal swab to determine S. aureus and methicillin-resistant S. aureus (MRSA) colonisation. Medical records were reviewed. 100 children were included, with a median of four complex chronic conditions. Sixteen percent had S. aureus colonisation, including two MRSA. S. aureus colonisation was associated with technology-dependent children, while being on antibiotic prophylaxis or having undergone antibiotic therapy in the previous month were protective factors. The prevalence of MR-GNB colonisation was 27%, which was associated with immunosuppressive therapy (aOR 31; 2.02-47]; p = 0.01), antibiotic prophylaxis (aOR 4.56; 1.4-14.86; p = 0.012), previously treated skin-infections (aOR 2.9; 1.07-8.14; p = 0.03), surgery in the previous year (aOR 1.4; 1.06-1.8; p = 0.014), and hospital admission in the previous year (aOR 1.79; [1.26-2.56]; p = 0.001). The rate of S. aureus nasal colonisation in this series was not high despite the presence of chronic conditions, and few cases corresponded to MRSA. Antibiotic prophylaxis, immunosuppressive therapies, history of infections, previous surgeries, and length of admission in the previous year were risk factors for MR-GNB colonisation.

Molecular diagnosis of bacteremia in a pediatric intensive care unit: a step forward.

Aim: T2Bacteria® Panel detects six ESKAPE pathogens in around 3.5 h directly in whole blood. Our aim was to compare T2Bacteria with simultaneous blood culture in critically ill children with suspected bloodstream infection. Materials & methods: Retrospective study of critically ill children admitted to our tertiary-care center (2018-2020). Results: A total of 60 patients were recruited, including 63 episodes and 75 T2Bacteria/blood cultures were performed. Overall agreement between T2Bacteria and blood culture was 78.7% with a discordance of 21.3% (16/75 samples). Conclusion: T2Bacteria Panel may be useful in critically ill children providing an accurate and fast diagnosis of bacteremia directly from blood sample and detecting pathogens not recovered in blood cultures.

SARS-CoV-2 Infection in Children and Adolescents Living With HIV in Madrid.

Multicenter study designed to describe epidemiologic and clinical characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive cases registered among children and adolescents living with HIV (CALWH). SARS-CoV-2 infection was confirmed in 13.3% of CALWH, with all patients presenting mild symptoms, and the outcome was good in all patients. None of the HIV- and antiretroviral treatment-related variables studied were associated with greater infection risk or could be considered protective.

Clinical and Epidemiologic Characteristics of a Cohort of HIV-Infected Mother-Infant Pairs During 21 Years.

BACKGROUND: HIV infection continues to be a worldwide public health problem. After the introduction of effective preventive measures, perinatal transmission dramatically decreased. Our aim was to assess the sociodemographic changes in pregnant women living with HIV infection and trends in perinatal transmission rates over time. SETTING: The Madrid cohort of HIV-infected mother-infant pairs is a multicenter, prospective, observational, and cohort study that collects information on HIV-infected pregnant women and their children. METHODS: Information on clinical-epidemiological characteristics of HIV-infected pregnant women until delivery and their children from 9 public hospitals was included. Data were collected from a standardized questionnaire from medical records. The results were classified in 3 periods: period 1 (P1) 2000-2006, period 2 (P2) 2007-2013, and period 3 (P3) 2014-2020. RESULTS: A total of 1521 women living with HIV and 1548 newborns were included. In P1, most mothers (75.8%) were Spanish, whereas in P2 and P3 there was a predominance of foreign origin [62.8% and 70.5% respectively ( P < 0.01)]. The percentage of women with antiretroviral treatment before pregnancy increased significantly in P3 ( P < 0.01). The proportion of Caesarean sections decreased over time ( P < 0.01): 66.2% (n = 472) in P1, 54.9% (n = 245) in P2, and 46.7% (n = 141) in P3. The percentage of preterm and low birth weight newborns showed a statistically significant decrease. Even though there were no statistically significant differences ( P = 0.154), a decrease in cases of perinatal infection was observed (1.6% in P1, 1.3% in P2 and 0.3% in P3). CONCLUSIONS: The epidemiologic characteristics of pregnant women with HIV infection have changed over time in our setting, with an increase of non-Caucasian, heterosexual, and perinatally infected mothers. Although there are still perinatal infections, especially in vulnerable populations such as immigrant women, transmission rate has markedly decreased in recent years and is still of major concern. Prevention measures should be reinforced in the most socially disadvantaged groups.

Lower nasopharyngeal viral loads in pediatric population. The missing piece to understand SARS-CoV-2 infection in children?

SARS-CoV-2 virus infects children but, contrary to other respiratory viruses, children tend to be asymptomatic or to have less symptoms than adults and are rarely the index case in household transmission chains. The aim of this study was to compare the relative viral loads in nasopharyngeal samples from children aged 0 to 17 years with those of an adult population. We selected 126 positive nasopharyngeal samples from children. Relative viral loads were measured by RT-PCR and the comparative ∆Ct method using primers and probes targeting the viral gene E and the human RNAseP. Relative viral loads were significantly lower in the children population than in the adult one.

High Rates of SARS-CoV-2 Family Transmission in Children of Healthcare Workers During the First Pandemic Wave in Madrid, Spain: Serologic Study.

BACKGROUND: Data on SARS-CoV-2 transmission among children living with healthcare workers (HCWs) are scarce. METHODS: A cross-sectional study was performed at a tertiary Hospital in Madrid, including children of HCW who suffered from SARS-CoV-2 infection between March and May 2020. Children underwent enzyme-linked immunosorbent serological study for detecting SARS-CoV-2 antibodies: VIRCELL IgG assay. RESULTS: One hundred thirteen children from 69 HCWs with confirmed SARS-CoV-2 infection were recruited: 47 children had positive IgG (41.6%). Children secondary attack rate was 43.7% (25% if both parents have had asymptomatic infection; 39.5% if one parent was symptomatic; and 47% when both parents had symptoms). Having a positive sibling was associated with a positive IgG result (odds ratio = 12.2; 95% confidence interval: 4.4-33.7, P < 0.001). Median age was higher in IgG positive children (P = 0.022). Children who referred anosmia presented higher IgG titles (P < 0.04). CONCLUSIONS: We observed a very high SARS-CoV-2 transmission in children of HCW during the first pandemic wave, especially when both parents were symptomatic. Having a positive sibling was associated with seroconversion, supporting the important role of family clusters in the transmission of SARS-CoV-2.

Characterization of methicillin-resistant Staphylococcus aureus strains colonizing the nostrils of Spanish children.

OBJECTIVE: To characterize the Staphylococcus aureus strains colonizing healthy Spanish children. METHODS: Between March and July 2018, 1876 Spanish children younger than 14 years attending primary healthcare centers were recruited from rural and urban areas. Staphylococcus aureus colonization of the anterior nostrils was analyzed. MecA and mecC genes, antibiotic susceptibility, and genotyping according to the spa were determined in all strains, and the following toxins were examined: Panton-Valentine leucocidin (pvl), toxic shock syndrome toxin (tst), and exfoliative toxins (eta, etb, etd). Multilocus sequence typing (MLST) and staphylococcal cassette chromosome (SCCmec) typing were performed on methicillin-resistant Staphylococcus aureus (MRSA) strains, as well as pulsed-field gel electrophoresis (PFGE). RESULTS: 619 strains were isolated in 1876 children (33%), and 92% of them were sent for characterization to the Spanish National Centre of Microbiology (n = 572). Twenty (3.5%) of these strains were mecA-positive. Several spa types were detected among MRSA, being t002 the most frequently observed (30%), associating with SCCmec IVc. Among MSSA, 33% were positive for tst, while only 0.73% were positive for pvl. The 20 MRSA strains were negative for pvl, and 6 (30%) harbored the tst gene. CONCLUSIONS: methicillin-resistant Staphylococcus aureus nasal colonization in Spanish children is rare, with t002 being the most observed spa type, associated with SCCmec IVc. None of the MRSA strains produced pvl, but up to 30% of S. aureus strains were positive for tst.

Safety and Experience With Combined Antiretroviral Prophylaxis in Newborn at High-risk of Perinatal HIV Infection, in a Cohort of Mother Living With HIV-infant Pairs.

BACKGROUND: Perinatal transmission of HIV has dramatically decreased in high-income countries in the last few years with current rates below 1%, but it still occurs in high-risk situations, mainly pregnant women with late diagnosis of infection, poor antiretroviral adherence and a high viral load (VL). In these high-risk situations, many providers recommend combined neonatal prophylaxis (CNP). Our aim was to evaluate the safety and toxicity of CNP in infants deemed at high-risk of HIV infection among mother-infant pairs in the Madrid Cohort. MATERIALS AND METHODS: Prospective, multicenter, observational cohort study between years 2000 and 2019. The subgroup of newborns on CNP and their mothers were retrospectively selected (cohort A) and compared with those who received monotherapy with zidovudine (cohort B). Infants with monotherapy were classified according to treatment regimes in long (6 weeks) and short (4 weeks) course. RESULTS: We identified 227 newborns (33.3% preterm and 7 sets of twins) with CNP. A maternal diagnosis of HIV-1 infection was established during the current pregnancy in 72 cases (36.4%) and intrapartum or postpartum in 31 cases (15.7%). Most infants received triple combination antiretroviral therapy (65.6%; n = 149). The perinatal transmission rate in cohort A was 3.5% (95% confidence interval: 1.13%-5.92%). Infants from cohort A developed anemia (26.1% vs. 19.4%, P = 0.14) and neutropenia more frequently at 50-120 days (21.4% vs. 10.9%, P < 0.01), without significant differences in grade 3 and 4 anemia or neutropenia between the two cohorts. There were no differences in increased alanine aminotransferase. Neutropenia was more common in the long zidovudine regimes. CONCLUSIONS: Our findings provide further evidence of the safety of CNP in infants with high-risk of HIV-1 perinatal transmission.