Prevención de la infección perinatal por estreptococo del grupo B. Recomendaciones españolas revisadas

[Group B streptococcal early-onset neonatal sepsis in the area of Barcelona (2004-2010). Analysis of missed opportunities for prevention]

OBJECTIVES

To study the evolution of the incidence of early-onset neonatal sepsis (EOS) by Streptococcus agalactiae in the area of Barcelona and to analyze failure of compliance with the prevention protocol.

METHODS

A retrospective review was carried out on EOS cases in 8 Health-Care Centers in the Barcelona area between 2004 and 2010.

RESULTS

Forty-nine newborns from 48 mothers were diagnosed with EOS. The incidence was 0.29‰ living newborns (0.18-0.47‰), with no significant differences in the fluctuations along the 7 years. The mortality rate was 8.16%. In 68.5% cases the maternal colonization studies were negative, and in 21% these studies were not performed. No risk factors were detected in 58.3% of pregnant women, and 22.9% of births were premature. In 58% of cases intra-partum antibiotic prophylaxis was not administered because it was not indicated, and in 42% due to failure to follow the protocol (3 strains were resistant to erythromycin). Resistance to clindamycin was 33.3%. The Streptococcus agalactiae serotypes more frequently isolated were iii, v, and ia.

CONCLUSIONS

No significant changes were detected in the incidence of Streptococcus agalactiae EOS in the 7 years of the study. The increased sensitivity of screening methods with the use of molecular techniques, the performance of susceptibility testing of strains isolated from pregnant women, and the improvement of communication between Health-Care Centers, can contribute to a better implementation of the protocol, as well as to reduce the incidence of EOS.

Neonatal group B streptococcal disease: from pathogenesis to preventive strategies

Streptococcus agalactiae, or group B streptococcus (GBS), remains the leading cause of neonatal sepsis and meningitis, as early-onset or late-onset diseases (EOD, LOD). Where consensus guidelines to detect and treat intrapartum women with GBS colonization have been widely adopted, incidence of neonatal EOD has dramatically declined. In response to both successful impacts on the incidence of GBS-EOD and analyses of missed opportunities, the first American guidelines for prevention issued in the 1990s have since been adapted in several stages to improve their efficacy. In some countries in Europe, nationwide guidelines, whether screening-based or risk-based, for the prevention of neonatal GBS diseases have also been issued and adopted, with the expected impact on incidence of GBS-EOD. In spite of universal screening, in spite of the great progress that has been made, GBS-EOD continues to occur and the GBS burden remains a significant public health issue. Continuous efforts to improve screening for GBS status continue to be important and may be able to take advantage of new rapid diagnostic technologies. The current screening-based strategy for prevention is highly effective but imperfect. Given the challenges, limitations and potential complications of maternal intrapartum prophylaxis, a new approach is still needed. Maternal immunization against GBS is an attractive alternative for the prevention of not only neonatal diseases but also stillbirths and maternal diseases. Vaccines against GBS may become the most effective and sustainable long-term preventive strategy.

[Late onset group B Streptococcus infection: 7 year experience in a tertiary hospital (2000-2006)]

INTRODUCTION

Group B Streptococcus (GBS) is a major cause of neonatal infection. Two forms of the disease have been described according to the age of presentation: early, beginning in the first 6 days of life, and late, occurring from day 7 up to 3 months of age.

OBJECTIVES

To analyze the epidemiology of the late onset form of GBS disease in a tertiary hospital after implementing preventive strategies aimed to reduce the rate of vertical transmission.

METHODS

We retrospectively reviewed the medical records of children diagnosed with late GBS infection between January 2000 and December 2006. Diagnostic criteria included a positive blood culture and/or a positive cerebrospinal fluid (CSF) culture for GBS in any patient aged between 7 and 89 days.

RESULTS

24 patients were identified, most of them presenting after January 2005. Median age was 36.2 days (range 9 to 81). GBS isolates in blood were found in 20 patients, 1 in CSF and 3 in both. Most frequently children presented with fever (70.8 %) and irritability (54.1 %). Five patients (20.8 %) had a cellulitis-adenitis syndrome. Cefotaxime and ampicillin were the most often used antibiotic combination. No ampicillin resistances were found.

CONCLUSIONS

The number of children with late GBS disease has increased in our center. Accordingly, the recent recommendations for the prevention of perinatal GBS vertical transmission were not effective for reducing late GBS infection. This may be due to horizontal infections from maternal sources, community or cross infections. It is important to maintain clinical suspicion of late GBS infection and start early antibiotic treatment.

Erythromycin resistance and genetic elements carrying macrolide efflux genes in Streptococcus agalactiae

The macrolide resistance determinants and genetic elements carrying the mef(A) and mef(E) subclasses of the mef gene were studied with Streptococcus agalactiae isolated in 2003 and 2004 from 7,084 vaginorectal cultures performed to detect carrier pregnant women. The prevalence of carriage was 18% (1,276 isolates), and that of erythromycin resistance 11.0% (129 of the 1,171 isolates studied). erm(B), erm(A) subclass erm(TR), and the mef gene, either subclass mef(A) or mef(E), were found in 72 (55.8%), 41 (31.8%), and 12 (9.3%) erythromycin-resistant isolates, while 4 isolates had more than 1 erythromycin resistance gene. Of the 13 M-phenotype mef-containing erythromycin-resistant S. agalactiae isolates, 11 had the mef(E) subclass gene alone, one had both the mef(E) and the erm(TR) subclass genes, and one had the mef(A) subclass gene. mef(E) subclass genes were associated with the carrying element mega in 10 of the 12 mef(E)-containing strains, while the single mef(A) subclass gene found was associated with the genetic element Tn1207.3. The nonconjugative nature of the mega element and the clonal diversity of mef(E)-containing strains determined by pulsed-field gel electrophoresis suggest that transformation is the main mechanism through which this resistance gene is acquired.

Multicenter study of the mechanisms of resistance and clonal relationships of Streptococcus agalactiae isolates resistant to macrolides, lincosamides, and ketolides in Spain

Macrolide, lincosamide, and ketolide mechanisms of resistance and clonal relationships were characterized in a collection of 79 resistant group B streptococcus isolates obtained from neonates or pregnant women. The erm(B), erm(TR), and mef(A) genes were present in 62%, 30.4%, and 3.8% of the isolates, respectively. There was considerable clonal diversity among them.