Evaluation of Antibiotic Resistance Pattern and Distribution of Capsule Types in Streptococcus Agalactiae Isolates Collected from Maternal-Newborn

Streptococcus agalactiae is one of the infectious agents in pregnant women and newborns. The capsule of this bacterium is importance in pathogenesis. This study aimed to investigate antibiotic resistance patterns and distribution of capsule types in S. agalactiae isolates collected from maternal-newborn.

First, using biochemical tests, S. agalactiae isolates were collected from the vagina and rectum of pregnant women and the ears and nose of newborns. Capsule types Ia, Ib, II, III, Iv, V, VI, VII, and VIII were identified by the ps1Ah, cps1bj, cps2k, cps1a / 2 / 3I, cps4N, cps5O, cps6I, cps7M and cps8j genes. Polymerase chain reaction (PCR) was used to amplify the genes.

In this study, 73 isolates (52.8%) were collected from rectovaginal, and 61 isolates (44.2%) were collected from the ear and nose. In rectovaginal specimens, tetracycline (82.1%) and erythromycin (83.5%) resistant strains were most common. Also, in nose and ear samples, resistance to rifampin (83.6%), erythromycin (98.3%), tetracycline (93.4%), and clindamycin (83.6%) showed high frequency. In both groups, capsule type III (14.4%), followed by capsule type II (7.9%), Ib (7.2%), and V (6.5%) had the highest frequency, respectively. Capsule types VIII, VII Ia, and VI were not detected in any of the isolates. The frequency of capsule types III, Ib, II, and V significantly increased antibiotic-resistant strains.

Our results showed that the high frequency of S. agalactiae capsule types in pregnant women has an essential role in increasing resistance to various antibiotics.