Loss of Catabolic Function in Streptococcus agalactiae Strains and Its Association with Neonatal Meningitis

Abstract

The abilities of 151 Streptococcus agalactiae strains to oxidize 95 carbon sources were studied using the Biolog system. Two populations were constituted: one with a high risk of causing meningitis (HR group; 63 strains), and the other with a lower risk of causing meningitis (LR group; 46 strains). Strains belonging to the HR group were significantly less able to use four carbon sources, i.e., ␣-D-glucose-1-phosphate, D-ribose, ␤-methyl-Dglucoside, and D,L-␣-glycerol phosphate, than strains from the LR group (P < 0.004). Moreover, strains in the HR group significantly more frequently possessed one of several mobile genetic elements or genome deletions previously shown to be associated with strains responsible for neonatal meningitis than strains in the LR group (P < 0.001). These findings suggest that genetic disruption might have occurred in virulent clones of S. agalactiae. Fifteen biotypes (B1 to B15) were identified from the results of oxidation of the four carbon sources, of which six (B1 to B6) included 92% of the isolates belonging to the HR group. Strains of biotypes B1 to B6 are thus 13 times more likely to be able to invade the central nervous system of neonates than strains of biotypes B7 to B15. In addition, 86% of strains recently associated with neonatal meningitis (42 strains studied) were identified as being of biotypes B1 to B6. Identification of particular S. agalactiae biotypes may therefore be one of the criteria to assist clinicians in assessing the level of risk of neonatal meningitis when a mother and/or her neonate is colonized with S. agalactiae.

The Threat of Aerobic Vaginitis to Pregnancy and Neonatal Morbidity

“…GBS exists as normal microbiota in the female genital tract and anal areas of healthy adults [43][44][45][46] , with an estimated one out of three women being a carrier of GBS. The gastrointestinal tract serves as the natural reservoir for GBS and is expected to be the source of vaginal colonization 23,43 .…”

“…The gastrointestinal tract serves as the natural reservoir for GBS and is expected to be the source of vaginal colonization 23,43 . Pregnant women who are colonized with GBS might develop infections of the urinary tract, bacteremia, chorioamnionitis, and postpartum endometritis 23,47,48 , thus increasing the risk of PTD, PPROM and perinatal transmission [49][50][51] , resulting in neonatal sepsis and meningitis 45,52,53 . A prevalence of 7 -25% GBS colonization in AV has been reported in women between 35 and 37 weeks of gestation 54 , with intrauterine infection associated with the ability of GBS to ascend from the lower genital tract and colonize the upper genital tract [54][55][56] .…”

Identification of Streptococcus agalactiae Isolates from Various Phylogenetic Lineages by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

“…Nevertheless, wide variations in protein expression have been reported, specifically according to the distribution of strains in various phylogenetic lineages that make up many species. For example, we have shown such variations in the expression of metabolic enzymes (12,13), in catabolic functions (3), and in the expression of surface-exposed bacterial proteins involved in adhesion and/or invasion of host cells (14). In addition, the diversity of the rRNA gene regions found in S. agalactiae isolates (2) may induce variations in the expression of the ribosomal proteins detected by MALDI-TOF MS, a method based mainly on detection of ribosomal protein fractions of bacteria (1,4,11).…”

Molecular Characterization and Lytic Activities of Streptococcus agalactiae Bacteriophages and Determination of Lysogenic-Strain Features

“…Amplification was performed over 40 cycles of 10 s at 94°C, 10 s at a hybridization temperature specific for each primer set (Table 1) Identification and localization of the 15 target genes used for multilocus characterization of phages by a PCR method and identified by an in silico analysis of eight sequenced S. agalactiae genomes. The target genes numbered 1 to 15 were located in the packaging cluster (1), the structural cluster (2, 3, 4, and 5), the host lysis cluster (6 and 7), the integrase genes (8 and 9), the lysogeny cluster (10, 11 and 12), the replication cluster (13), and the transcriptional regulation cluster (14 and 15). 95°C.…”