Antibiotic Resistance and Molecular Epidemiological Characteristics of Streptococcus agalactiae Isolated from Pregnant Women in Guangzhou, South China

Abstract

Streptococcus agalactiae colonization in pregnant women can cause postpartum intrauterine infections and life-threatening neonatal infections. To formulate strategies for the prevention and treatment of S. agalactiae infections, we performed a comprehensive analysis of antibiotic resistance and a molecular-based epidemiological investigation of S. agalactiae in this study. Seventy-two S. agalactiae strains, collected from pregnant women, were subjected to antibiotic susceptibility tests; then, the screened erythromycin and clindamycin nonsusceptible isolates were used for macrolides and clindamycin resistance genes detection, respectively. Detection of resistance genes, serotyping, and determination of virulence genes were performed by polymerase chain reaction. The clonal relationships among the colonized strains were evaluated by multilocus sequence typing. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) mass peak analysis was performed to discriminate the specific sequence types (STs). In our study, 69.4% and 47.2% of the strains were nonsusceptible to erythromycin and clindamycin, respectively; the multidrug resistance rate was 66.7%. All erythromycin nonsusceptible strains harbored resistance genes, whereas only 52.9% of the clindamycin nonsusceptible strains possessed the linB gene. Erythromycin resistance was mainly mediated by the ermB or mefA/E genes. Four serotypes were identified, and the most common serotype was serotype III (52.8%), followed by Ib (22.2%), Ia (18.0%), and II (4.2%). All the strains were divided into 18 STs that were assigned to nine clonal complexes. Most of the major STs were distributed into specific serotypes, including ST19/serotype III, ST17/serotype III, ST485/serotype Ia, ST862/serotype III, and ST651/serotype III. Analysis of virulence genes yielded seven clusters, of which bca-cfb-scpB-lmb (61.6%) was the predominant virulence gene cluster. Among all ST strains distributed in this region, only the ST17 strains had a mass peak at 7620 Da. The outcomes of this study are beneficial for the epidemiological comparison of colonized S. agalactiae in different regions and may be helpful for developing the strategies for the prevention of S. agalactiae infection in Guangzhou. Furthermore, our results show that MALDI-TOF MS can be used for the rapid identification of the ST17 strains.

Frequency and Antibiotic Susceptibility Patterns of <em>Streptococcus Agalactiae</em> Strains Isolated from Women in Yaounde, Cameroon

“…resistance to erythromycin and clindamycin [16]; another in Ethiopia reported 26.5% and 21.4% [14] These reports are in accordance with the results of our study.…”

Epidemiological Characterization of Group B Streptococcus Infections in Alberta, Canada: An Update from 2014 to 2020

“…However, almost all GBS isolates that were nonsusceptible to clindamycin were also nonsusceptible to erythromycin ( n = 689, 96.77%). Similar rates of resistance to erythromycin and clindamycin have been observed in various parts of the world, including Canada, the United States, Europe, China, and Taiwan ( 28 , 43 , 47 , 51 – 55 ). Resistance to erythromycin and clindamycin is primarily associated with ermB , ermTR , or mef ( 56 ).…”

To Evaluate Impact on Detection Rate of Streptococcus Agalactiae in the Third Trimester of Pregnancy

“…Because of the streptococcus agalactiae infectious leading to early neonatal morbidity and mortality,the streptococcus agalactiae examination is important for pregnant women. Many meta-analysis studies shown that approximately 50% streptococcus agalactiae colonization pregnant women maybe transmit the bacteria by delivery process to their newborns now [27][28][29].The populations in developing or underdeveloped countries have different lifestyles, live in different geographical locations, different ages, socioeconomic levels, schooling, and gestational ages and have different importance for streptococcus agalactiae infectious [11,12,15,18,[30][31][32][33][34]. it is essential to improve and extend streptococcus agalactiae screening performance and accuracy in pregnant women, especially underdeveloped countries.…”