Emergence of Multi-Drug Resistance and Its Association With Uncommon Serotypes of Streptococcus agalactiae Isolated From Non-neonatal Patients in Thailand

Global patterns of antibiotic resistance in group B Streptococcus: a systematic review and meta-analysis

Objectives

Streptococcus agalactiae, or group B Streptococcus (GBS), is a significant pathogen associated with severe infections in neonates, particularly sepsis and meningitis. The increasing prevalence of antibiotic resistance among GBS strains is a growing public health concern, necessitating a comprehensive meta-analysis to evaluate the prevalence of this resistance globally.

Methods

We conducted a comprehensive systematic search across four major scientific databases: Scopus, PubMed, Web of Science, and EMBASE, targeting articles published until December 13, 2023. This meta-analysis focused on studies that examined antibiotic resistance in GBS strains. The Joanna Briggs Institute tool was employed to assess the quality of the included studies. This meta-analysis applied a random-effects model to synthesize data on antibiotic resistance in GBS, incorporating subgroup analyses and regression techniques to explore heterogeneity and trends in resistance rates over time. Outliers and influential studies were identified using statistical methods such as Cook's distance, and funnel plot asymmetry was assessed to evaluate potential publication bias. All analyses were conducted using R software (version 4.2.1) and the metafor package (version 3.8.1).

Results

This study included 266 studies from 57 countries, revealing significant variability in GBS antibiotic resistance rates. The highest resistance rates were observed for tetracycline (80.1, 95% CI: 77.1-82.8%), while tedizolid (0.1, 95% CI: 0.0-0.8%) showed the lowest resistance rates. Significant heterogeneity in resistance rates was observed, particularly for antibiotics such as azithromycin and gentamicin (I 2 = 97.29%), variability across studies. On the other hand, tigecycline and ceftaroline exhibited no heterogeneity (I 2 = 0%), suggesting consistent resistance patterns. Subgroup analyses revealed disparities in resistance rates based on country, continent, and methodological categories. Significant increase in resistance rates for several antibiotics over time, including clindamycin, erythromycin, ceftriaxone, cefuroxime, ciprofloxacin, levofloxacin, moxifloxacin, chloramphenicol, and ofloxacin. Ofloxacin and cefuroxime showed particularly steep trends. Conversely, a declining resistance trend was observed for oxacillin.

Conclusion

This study emphasizes the growing issue of antibiotic resistance in GBS strains. Notable resistance to older and newer antibiotics, increasing resistance over time, regional disparities, and methodological variations are noted. Rising resistance trends for multiple antibiotics underscore the urgent need for global surveillance and improved antibiotic stewardship.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/view/CRD42024566269, CRD42024566269.

Predomination of hypervirulent ST283 and genetic diversity of levofloxacin resistance in multidrug-resistant, hypervirulent Streptococcus agalactiae in Thailand

Introduction. Group B Streptococcus (GBS) is a multi-host pathogen causing pneumonia and meningitis in humans as well as streptococcal diseases in tilapia and mastitis in cattle. Thailand has experienced a significant increase in GBS infections that greatly impact health and economics.Gap statement. The antimicrobial resistance (AMR) and genotype data of GBS in Thailand are still limited and require further study.Aim. This study aimed to describe AMR profiles and molecular characteristics, especially antimicrobial resistance genes (ARGs) and virulence factor (VF) genes of GBS in Thailand.Methodology. AMR profiles of 221 GBS isolates from humans, fish and freshwater were examined. Whole-genome sequencing of 41 representative isolates was used to investigate capsular genotypes and sequence types (STs), ARGs and VF genotypes.Results. All GBS isolates were susceptible to penicillin; the majority (99.1%) showed resistance to tetracycline. In addition, the rates of resistance to clindamycin, erythromycin and levofloxacin were 22.6%, 20.4% and 2.3%, respectively; multidrug-resistant (MDR) isolates (TE-E-CM and TE-E-CM-LVX) were 19.5%. Among 41 representative isolates, the dominant types were capsular genotype III (63.4%) and ST283 (43.9%). ARGs associated with resistance to tetracycline (tetM, tetO and tetS), erythromycin (ermB, ermA, mefA and msrD) and clindamycin (lsaC, lsaE and lnuB) were identified. Additionally, point mutations responsible for levofloxacin resistance, S81L in GyrA, S79F/Y in ParC and H221Y in ParE, were found. The MDR isolates belonged to various STs, predominantly clustering in capsular types III (60.0%) and Ib (30.0%). The MDR-hypervirulent ST17 and ST19 harboured multiple ARGs and mutations affecting quinolone resistance. Different VF gene patterns were found among hypervirulent STs (ST12, ST17, ST19 and ST283). Notably, a unique nt deletion [c.(1013_1020)delG] in pilA was found only in ST283.Conclusion. This study elucidated significant antimicrobial characteristics of a substantial number of GBS in Thailand. Moreover, the distribution of the hypervirulent ST283 and the genotypes of MDR-hypervirulent GBS were first described.

Molecular evidence that GBS early neonatal sepsis results from ascending infection: comparative hybrid genomics analyses show that microorganisms in the vaginal ecosystem, amniotic fluid, chorioamniotic membranes, and neonatal blood are the same

OBJECTIVES

Streptococcus agalactiae, or Group B Streptococcus (GBS), is a leading cause of neonatal sepsis. Materno-fetal transmission of the microorganisms present in the lower genital tract/perineum is considered to be the most frequent mode for acquisition of infection. It has also been proposed that, in a subset of cases, GBS causes acute chorioamnionitis, intraamniotic infection, and fetal/neonatal sepsis. However, the evidence to support this ascending pathway is derived from microbiologic studies that rely on cultivation methods, which do not have the resolution to determine if the microorganisms causing neonatal sepsis are the same as those found in the amniotic fluid and the vaginal ecosystem.

METHODS

We used whole genome sequencing of the microorganisms isolated from the vagina, amniotic fluid, chorioamniotic membranes, and neonatal blood (four isolates) in a case of early neonatal sepsis. Using hybrid genome assembly, we characterized the genomic features including virulence factors and antimicrobial resistance in four isolates from the same mother, placenta, and newborn.

RESULTS

Whole genome sequencing revealed that the microorganisms in the four clinical isolates corresponded to S. agalactiae sequence type 1, clonal complexes 1, and serotype Ib. Comparative genomic analysis illustrated similar DNA sequences of the four genomes.

CONCLUSIONS

This study presents the first evidence of the genomic similarity of microorganisms in the vaginal ecosystem, the space between the chorioamniotic membranes of the placenta, amniotic fluid, and neonatal blood.

First report of Streptococcus agalactiae isolated from a healthy captive sichuan golden snub-nosed monkey (Rhinopithecus roxellana) in China

Streptococcus agalactiae (S. agalactiae) is an opportunistic pathogen, and to date, studies have mainly focused on S. agalactiae strains isolated from humans, dairy cows, and fish. We reported one S. agalactiae strain, named CFFB, which was isolated from a healthy Sichuan golden snub-nosed monkey. Classical bacteriological approaches, as well as, next-generation sequencing, comparative genomics, and mice challenge test were used to characterize this strain. CFFB was identified as serotype III, ST19 combination which is a common type found in human strains. Phylogenetic analysis showed that the genome of CFFB was closely related to human clinical isolates, rather far away from animal strains. In total, CFFB contained fewer virulence-associated genes and antibiotic resistance genes than human isolates that were close to CFFB in evolutionary relationships. In the mice challenge test, CFFB had a relative weak virulence that just caused death in 33 % of ICR mice at a dose of 108 CFU by intraperitoneal injection, and CFFB was reisolated from the cardiac blood of the dead mice. Meanwhile, two intact prophages (prophage 1 and 2) were identified in the CFFB genome and shared high similarities with phage Javan52 and Javan29 which from human S. agalactiae isolate Gottschalk 1002A and RBH03, respectively. Moreover, the type II-A CRISPR-Cas system was detected in the CFFB genome, and the spacers from CFFB were the same to the streptococci isolates from human. These results suggest that CFFB isolated from healthy Sichuan golden snub-nosed monkeys may have its origin in human S. agalactiae. Our results suggested some genomic similarities between the S. agalactiae colonized in Sichuan golden snub-nosed monkey and those in infected humans.

Current research update on group B streptococcal infection related to obstetrics and gynecology

Group B streptococcal (GBS) is a Gram-positive bacterium that is commonly found in the gastrointestinal tract and urogenital tract. GBS infestation during pregnancy is a significant contributor to maternal and neonatal morbidity and mortality globally. This article aims to discuss the infectious diseases caused by GBS in the field of obstetrics and gynecology, as well as the challenges associated with the detection, treatment, and prevention of GBS.

Analysis of distribution and antibiotic resistance of Gram-positive bacteria isolated from a tertiary-care hospital in southern China: an 8-year retrospective study

Objective

Due to the severe drug resistance situation of Gram-negative bacteria, especially Gram-negative enterobacter, relatively little attention has been paid to the changes in Gram-positive bacteria species and drug resistance. Therefore, this study analyzed the prevalence and drug resistance of Gram-positive bacteria in a general tertiary-care hospital from 2014 to 2021, in order to discover the changes in Gram-positive bacteria distribution and drug resistance that cannot be easily identified, inform clinicians in their respective regions when selecting antimicrobial agents, and to provide the basis for the diagnosis of Gram-positive bacterial infection, and for the comprehensive and multi-pronged prevention and control of drug-resistant bacteria.

Methods

A retrospective study was conducted on Gram-positive bacteria isolated from patients presented to a general tertiary-care hospital from January 2014 to December 2021. A total of 15,217 Gram-positive strains were analyzed.

Results

During the 8-year period, the total number and the species of Gram-positive bacteria isolated from clinic increased continuously. The seven most common species were Streptococcus pneumoniae (21.2%), Staphylococcus aureus (15.9%), Enterococcus faecium (20.6%), Enterococcus faecalis (14.0%), and Staphylococcus epidermidis (7.8%), Staphylococcus haemolyticus (4.8%), Streptococcus agalactiae (3.6%). The isolation rates of Staphylococcus aureus and Streptococcus agalactiae increased, and the isolation rate of Enterococcus faecium decreased. The resistance rates of Staphylococcus aureus to erythromycin, clindamycin, tetracycline, rifampicin and furantoin decreased obviously. The resistance rates of Streptococcus pneumoniae to cefepime (non-meningitis) and ceftriaxone (meningitis) decreased significantly. The resistance rates of Enterococcus faecium to penicillin, ampicillin, erythromycin, levofloxacin, ciprofloxacin and furantoin rose rapidly from 50.3, 47.6, 71.5, 44.9, 52.3, and 37.5% in 2014 to 93.1, 91.6, 84.9, 86.8, 86.8, and 60.0% in 2021, respectively.

Conclusion

The total number and the species of Gram-positive bacteria isolated during the 8-year period increased continuously. Streptococcus pneumoniae and Staphylococcus aureus are the main causes of positive bacterial infections in this hospital. The resistance rates of Enterococcus faecium to a variety of commonly used antibiotics increased significantly. Therefore, it is very important to monitor the distribution of bacteria and their resistance to antibiotics to timely evaluate and identify changes in drug resistance that are not easily detected.

Maternal colonization with group B Streptococcus and antibiotic resistance in China: systematic review and meta-analyses

BACKGROUND

Maternal rectovaginal colonization with group B Streptococcus (GBS) or Streptococcus agalactiae is the most common pathway for this disease during the perinatal period. This meta-analysis aimed to summarize existing data regarding maternal colonization, serotype profiles, and antibiotic resistance in China.

METHODS

Systematic literature reviews were conducted after searching 6 databases. Meta-analysis was applied to analyze colonization rate, serotype, and antimicrobial susceptibility of GBS clinical isolates in different regions of China. Summary estimates are presented using tables, funnel plots, forest plots, histograms, violin plots, and line plots.

RESULTS

The dataset regarding colonization included 52 articles and 195 303 pregnant women. Our estimate for maternal GBS colonization in China was 8.1% (95% confidence interval [CI] 7.2%-8.9%). Serotypes Ia, Ib, III, and V account for 95.9% of identified isolates. Serotype III, which is frequently associated with the hypervirulent clonal complex, accounts for 46.4%. Among the maternal GBS isolates using multilocus sequence typing (MLST), ST19 (25.7%, 289/1126) and ST10 (25.1%, 283/1126) were most common, followed by ST12 (12.4%, 140/1126), ST17 (4.8%, 54/1126), and ST651 (3.7%, 42/1126). GBS was highly resistant to tetracycline (75.1% [95% CI 74.0-76.3%]) and erythromycin (65.4% [95% CI 64.5-66.3%]) and generally susceptible to penicillin, ampicillin, vancomycin, ceftriaxone, and linezolid. Resistance rates of GBS to clindamycin and levofloxacin varied greatly (1.0-99.2% and 10.3-72.9%, respectively). A summary analysis of the bacterial drug resistance reports released by the China Antimicrobial Resistance Surveillance System (CARSS) in the past 5 years showed that the drug resistance rate of GBS to erythromycin, clindamycin, and levofloxacin decreased slowly from 2018 to 2020. However, the resistance rates of GBS to all 3 antibiotics increased slightly in 2021.

CONCLUSIONS

The overall colonization rate in China was much lower than the global colonization rate (17.4%). Consistent with many original and review reports in other parts of the world, GBS was highly resistant to tetracycline. However, the resistance of GBS isolates in China to erythromycin and clindamycin was greater than in other countries. This paper provides important epidemiological information, to assist with prevention and treatment of GBS colonization in these women.

Alterations in Genes rib, scpB and Pilus Island Decrease the Prevalence of Predominant Serotype V, Not III and VI, of Streptococcus agalactiae from 2008 to 2012

Streptococcus agalactiae (GBS) can infect newborns, pregnant women and immunocompromised or elderly people. This study aimed to investigate differences in three pilus genes and virulence genes pavA, cfb, rib and scpB and changes in predominant serotypes III, V and VI from 2008 to 2012. The susceptibilities to penicillin, ceftriaxone, azithromycin, erythromycin, clindamycin, levofloxacin and moxifloxacin of 145 GBS strains of serotype III, V and VI strains from 2008 and 2012 were determined using disc diffusion method. PCR identification of ST-17, the pilus genes and virulence genes; multilocus sequence typing (MLST); and conserved domain and phylogenetic analysis of scpB-1 and scpB-2 proteins were performed. A dramatic number reduction was observed in serotype V, not III and V, from 2008 to 2012. The rate of resistance to azithromycin, clindamycin and erythromycin was the highest in serotype V. ST-17 was only found in serotype III with pilus genes PI-1+PI-2b. The major pilus genotype was PI-1+PI-2a. Serotype V without the rib gene was reduced in number between two studied years. Compared to scpB-1, scpB-2 had a 128-bp deletion in a PA C5a-like peptidase domain and putative integrin-binding motif RGD. In conclusion, reduction in serotype V may be due to presence of scpB-2 or lack of genes scpB and rib.

Bacteriocin Producing Streptococcus agalactiae Strains Isolated from Bovine Mastitis in Brazil

Antibiotic resistance is one of the biggest health challenges of our time. We are now facing a post-antibiotic era in which microbial infections, currently treatable, could become fatal. In this scenario, antimicrobial peptides such as bacteriocins represent an alternative solution to traditional antibiotics because they are produced by many organisms and can inhibit bacteria, fungi, and/or viruses. Herein, we assessed the antimicrobial activity and biotechnological potential of 54 Streptococcus agalactiae strains isolated from bovine mastitis. Deferred plate antagonism assays revealed an inhibition spectrum focused on species of the genus Streptococcus—namely, S. pyogenes, S. agalactiae, S. porcinus, and S. uberis. Three genomes were successfully sequenced, allowing for their taxonomic confirmation via a multilocus sequence analysis (MLSA). Virulence potential and antibiotic resistance assessments showed that strain LGMAI_St_08 is slightly more pathogenic than the others. Moreover, the mreA gene was identified in the three strains. This gene is associated with resistance against erythromycin, azithromycin, and spiramycin. Assessments for secondary metabolites and antimicrobial peptides detected the bacteriocin zoocin A. Finally, comparative genomics evidenced high similarity among the genomes, with more significant similarity between the LGMAI_St_11 and LGMAI_St_14 strains. Thus, the current study shows promising antimicrobial and biotechnological potential for the Streptococcus agalactiae strains.