Streptococcus agalactiae in pregnant women: serotype and antimicrobial susceptibility patterns over five years in Eastern Sicily (Italy)

Abstract

Streptococcus agalactiae (also known Group B Streptococcus or GBS) represents the main pathogen responsible for early- and late-onset infections in newborns. The present study aimed to determine the antimicrobial susceptibility pattern and the capsular serotypes of GBS isolated in Eastern Sicily over 5 years, from January 2015 to December 2019. A total of 3494 GBS were isolated from vaginal swabs of pregnant women (37–39 weeks), as recommended by the Centers for Disease Control and Prevention. Capsular polysaccharide’s typing of GBS was determined by a commercial latex agglutination test containing reagents to serotypes I–IX. The antimicrobial resistance pattern of GBS was determined through the disk diffusion method (Kirby-Bauer) and the double-disk diffusion test on Mueller-Hinton agar plates supplemented with 5% defibrinated sheep blood, according to the guidelines of the Clinical and Laboratory Standards Institute. Serotypes III (1218, 34.9%) and V (1069, 30.6%) were the prevalent colonizers, followed by not typable (570, 16.3%) and serotypes Ia (548, 15.7%), Ib (47, 1.3%), II (40, 1.1%), and IV (2, 0.1%). All 3494 clinical isolates were susceptible to cefditoren and vancomycin. Resistance to penicillin, ampicillin, levofloxacin, clindamycin, and erythromycin was observed in 6 (0.2%), 5 (0.1%), 161 (4.6%), 1090 (31.2%), and 1402 (40.1%) of the strains, respectively. Most of erythromycin-resistant GBS (1090/1402) showed the cMLSB phenotype, 276 the M phenotype, and 36 the iMLSB phenotype. Our findings revealed a higher prevalence of serotype III and a relevant resistance rate, among GBS strains, to the most frequently used antibiotics in antenatal screening.

In Vitro Antibacterial, Anti-Adhesive and Anti-Biofilm Activities of Krameria lappacea (Dombey) Burdet & B.B. Simpson Root Extract against Methicillin-Resistant Staphylococcus aureus Strains

“…Macrolide-lincosamide-streptogramin B (MLS B ) phenotypes were determined by the double-disk diffusion test on MHA, as previously described [ 54 ].…”

High Rates of Streptococcus Agalactiae Clindamycin and Erythromycin Resistance in Vietnamese Pregnant Women

“…Similar to other reports (21,23), none of the isolates resistant to penicillin, ampicillin, and vancomycin was found in this study. Although the GBS resistance to ampicillin, penicillin, and vancomycin has been documented (22,24,25), penicillin and ampicillin remain the drugs of choice for intrapartum antibiotic prophylaxis for GBS colonization in Vietnamese pregnant women.…”

Group B Streptococcus serotypes associated with different clinical syndromes: Asymptomatic carriage in pregnant women, intrauterine fetal death, and early onset disease in the newborn

“…The high resistance rates described by us prohibits empirical use of these antibiotics for women with penicillin allergy. The increasing reports regarding penicillin resistance [ 12 , 13 ] warrant also routine susceptibility test for penicillin.…”

“…Recent data reports increasing rates of macrolide resistance [ 10 , 11 ]. Also, several recent studies demonstrated a worrying increase in GBS isolates with resistance to penicillin [ 12 , 13 ]. In Israel, screening does not include antibiotic susceptibility and there is no data regarding GBS resistance rates.…”