[Analysis of screening tests for Streptococcus agalactiae in pregnant women from the West Pomeranian region].

OBJECTIVE

The aim of the study was to determine the degree of colonization Streptococcus agalactiae (GBS--Group B Streptococcus) in women at 35.-37. weeks of pregnancy and to evaluate drug susceptibility of the isolated strains.

MATERIAL AND

METHODS

We analyzed the results of 1111 tests for GBS colonization performed between 2010-2013 in pregnant women (aged 16-40) from the West Pomeranian region. Swabs were taken from the vagina and the anus of the study subjects at 35.-37. weeks of pregnancy Materials were cultured on Granada Agar and in selective Todd-Hewitt broth, which was next cultured on Granada Agar The degree of GBS colonization was determined by the semi-quantitative method on solid media. The strains were tested for susceptibility to penicillin, erythromycin and clindamycin by disc diffusion method according to the EUCAST standards.

RESULTS

Positive cultures for S. agalactiae were found in 22.5% of the pregnant women. The highest (25.4%) and the lowest (15.9%) rates of GBS colonization were observed in the age groups of 31-35 and 16-20 years, respectively Massive GBS colonization was detected in 68.4% of pregnant subjects, with the highest and the lowest rates in the age groups of 31-35 and 16-20 years, (75.3% and 50.0%, respectively). All isolated GBS strains were sensitive to penicillin. Macrolide, lincosamide and streptogramin B resistance (MLSB) was found in 28% of the isolates, resistance only to erythromycin (phenotype M) in 2% of the strains. There were no significant differences in the degree of GBS colonization and drug sensitivity of GBS strains versus the year of our examination.

CONCLUSIONS

Monitoring for GBS colonization in the last weeks of pregnancy seems to be necessary for effective prevention of S. agalactiae infections.