Survival and biofilm formation by Group B streptococci in simulated vaginal fluid at different pHs

The Group B Streptococcus (GBS, Streptococcus agalactiae) is an important cause of neonatal and maternal infection. GBS is a commensal organism of the lower gastrointestinal and vaginal tract. A frequent mode of neonatal infection is vertical transmission from pregnant women to their foetus or neonate. The aim of this study was to evaluate the survival and biofilm production of 10 GBS strains in simulated vaginal fluid at pH 4.2, 5.5 and 6.5. GBS survived longer at higher pH than at normal vaginal pH. At pH 4.2, with the exception of two isolates that were recovered up to 48 and 72 h, viable GBS numbers declined below the limit of detection by 24 h. At higher pH, GBS survived between 3 and 15 days. All isolates investigated were biofilm producers but biofilm production was greater in tryptone soy broth compared to simulated vaginal fluid. The quantity of biofilm produced increased with the rise in the pH. This study suggests that high vaginal pH may influence both GBS survival and biofilm production and thus could be a risk factor for GBS infection.     

妊娠晚期阴道B族链球菌的感染对肠道菌群和妊娠结局的影响

目的探究妊娠晚期阴道B族链球菌(group B Streptococcus,GBS)的感染对肠道菌群和妊娠结局的影响。方法选取2018年3月至2019年11月大连市中心医院孕检并分娩的妊娠妇女744人为对象,调查并统计B族链球菌的感染率;筛选有和没有B族链球菌感染妊娠妇女各47人,调查不良妊娠结局的发生率;选取信息匹配的妊娠晚期阴道B族链球菌感染和未感染的妊娠妇女,采集粪便样本,提取菌群DNA,用16S rDNA方法分析菌群变化。结果744名妊娠妇女中B族链球菌检出49例,感染率为6.59%;B族链球菌感染组总的不良妊娠发生比例为76.6%,正常组发生比例为27.7%(χ^2=5.491,P<0.05)。B族链球菌感染组妊娠妇女胎膜早破(χ^2=16.177,P<0.01)、难产(χ^2=21.134,P<0.01)和羊水异常(χ^2=22.989,P<0.05)的发生率与未感染组比较显著增高。B族链球菌感染组妊娠妇女肠道菌群发生显著变化。结论妊娠晚期阴道B族链球菌的感染可能引起肠道菌群紊乱,增加不良妊娠结局。     

B族链球菌感染及微量元素营养干预对产妇阴道微生态的影响

分析产妇阴道微生态失衡的发生情况和B族链球菌（GBS）感染及营养相关因素在正常与微生态失衡产妇中的差异,同时检验不同干预的效果。

选取2020年1月—2021年6月本院就诊的105例产妇作为研究对象,采用随机数字表法将其分为观察组（51例）和对照组（54例）。对照组患者接受常规医疗照护干预,观察组在对照组基础上接受个体化营养干预（视产妇具体血清微量元素水平情况）,比较两组产妇阴道菌群分布、GBS感染、血清微量元素分布和新生儿情况。

全部受试对象阴道内优势菌群前5位依次是菌群抑制无优势菌、非典型乳杆菌类革兰阳性杆菌、革兰阳性短杆菌、革兰阳性大杆菌、革兰阳性球菌。阴道微生态指标检测结果显示,阴道微生态失衡产妇共49例,阴道微生态正常产妇共56例。阴道微生态失衡产妇的GBS感染率更高（30.61% vs 5.36%）,且微量元素锌和硒缺乏情况更为严重（P＜0.05）。营养干预后,观察组阴道菌群的分布异常情况改善优于对照组,且菌群多样性正常比例、锌和维生素D水平高于对照组,而GBS感染率低于对照组（P＜0.05）。

GBS感染可加重产妇阴道微生态紊乱,增加不良妊娠结局发生风险,而营养相关干预能够减低GBS感染率并提高微量元素的血清水平,有利于产妇健康,值得临床推广。

     

Extraction Parameters Significantly Influence the Quantity and the Profile of PLFAs Extracted from Soils

The female genital tract (FGT) harbors very large numbers of bacterial species that are known to play an important role on vaginal health. Previous studies have focused on bacterial diversity in the vagina, but little is known about the ectocervical microbiota associated with FGT infections. In our study, vaginal swabs and ectocervical swabs were collected from 100 participants in China, including 30 women with bacterial vaginosis (BV; BV group), 22 women with cervicitis (Cer group), 18 women with BV in combination with cervicitis (BC group) and 30 healthy control women (CN group). The diversity and richness of cervicovaginal microbiota were investigated with culture-independent polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) targeting 11 microorganisms that have been associated with FGT infections. Despite significant interpersonal variations, the PCR-DGGE profiles revealed that vaginal microbiota and ectocervical microbiota were clearly much more complex in the BV group, while the ectocervical microbiota showed no significant difference between healthy and diseased participants. Using species-specific qPCR, BV and cervicitis were significantly associated with a dramatic decrease in Lactobacillus species (p < 0.05), and potential pathogenic species such as Gardnerella, Atopobium, Eggerthella, Leptotrichia/Sneathia, and Prevotella were more common and in higher copy numbers in BV than in CN samples (p values ranged from 0.000 to 0.021). No significant differences were observed between healthy and cervicitis samples (p > 0.05) in ectocervical microbiota. The total numbers of bacteria were significantly lower in the ectocervix as compared in the vagina (p < 0.05). Intriguingly, vaginal microbiota from participants with BV in combination with cervicitis was quite different from that of participants with BV or cervicitis alone. Our study demonstrated that the cervicovaginal microbiota was actively involved in the process of FGT infections. The predominant bacteria of the cervicovaginal communities were clearly associated with BV; however, there was not sufficient evidence that the ectocervical microbiota is directly involved in the development of cervicitis.     

口服微生态制剂对孕妇肠道和阴道大肠杆菌K1和B族链球菌定殖的干预

【目的】本研究主要从临床探讨口服益生菌对孕妇微生态环境(阴道和肠道)中Escherichia coli K1和B族链球菌(GBS)定殖率的影响以预防新生儿血流播散性细菌性脑膜炎。【方法】收集2011年至2017年期间在广东省范围门诊就诊的2539例妊娠健康孕妇的阴道、直肠分泌物。选择符合要求的32孕周孕妇47例随机分成两组,其中益生菌组22例,对照组25例,用荧光定量PCR检测不同组孕妇体内服药前、后的微生态环境中大肠埃希菌的变化。然后选择50例GBS筛查阳性的35孕周孕妇,随机分成益生菌组和对照组,荧光定量PCR检测不同分组孕妇体内微生态环境中GBS定量变化。同时使用荧光PCR筛查对临床收集的2539例孕晚期(35周)孕妇生殖道、直肠分泌物标本进行GBS检测并计算携带率。【结果】研究前对不同组别孕妇的基本资料进行差异分析,结果显示两组在年龄差别、经产妇比例和受教育水平3个方面比较均无差异(P0.05),证明不同组间孕妇具有可比性。然后观察上述不同组别的孕妇服用益生菌体内微生态状况,用荧光定量PCR方法进行检测,结果显示用益生菌组在服药前后,阴道和直肠分泌物中大肠杆菌数量显著下降(F=32.866,P0.001),孕妇服用益生菌后E. coli K1的数量显著低于服用益生菌前(P0.05),且益生菌组与对照组相比大肠杆菌数量显著下降(P0.05,F=41.546,P0.001);同时检查服益生菌组孕妇体内GBS的变化,荧光定量PCR检测结果显示服用益生菌前后GBS的定殖数量有降低趋势,且与对照组相比有下降趋势。最后我们用荧光定量PCR筛查孕晚期妇女B族链球菌带菌状况,其GBS携带率为8.07%。【结论】本研究结果提示本文筛查的广东省孕晚期孕妇的B族链球菌平均携带率为8.07%,GBS可能是新生儿发生细菌性脑膜炎的危险因素之一;口服益生菌疗法可能通过抑制E. coli K1在孕妇肠道和生殖道的定殖以预防血流播散性新生儿细菌性脑膜炎。     

Serine-rich repeat proteins and pili promote Streptococcus agalactiae colonization of the vaginal tract

Streptococcus agalactiae (group B streptococcus [GBS]) is a Gram-positive bacterium found in the female rectovaginal tract and is capable of producing severe disease in susceptible hosts, including newborns and pregnant women. The vaginal tract is considered a major reservoir for GBS, and maternal vaginal colonization poses a significant risk to the newborn; however, little is known about the specific bacterial factors that promote GBS colonization and persistence in the female reproductive tract. We have developed in vitro models of GBS interaction with the human female cervicovaginal tract using human vaginal and cervical epithelial cell lines. Analysis of isogenic mutant GBS strains deficient in cell surface organelles such as pili and serine-rich repeat (Srr) proteins shows that these factors contribute to host cell attachment. As Srr proteins are heavily glycosylated, we confirmed that carbohydrate moieties contribute to the effective interaction of Srr-1 with vaginal epithelial cells. Antibody inhibition assays identified keratin 4 as a possible host receptor for Srr-1. Our findings were further substantiated in an in vivo mouse model of GBS vaginal colonization, where mice inoculated with an Srr-1-deficient mutant exhibited decreased GBS vaginal persistence compared to those inoculated with the wild-type (WT) parental strain. Furthermore, competition experiments in mice showed that WT GBS exhibited a significant survival advantage over the ΔpilA or Δsrr-1 mutant in the vaginal tract. Our results suggest that these GBS surface proteins contribute to vaginal colonization and may offer new insights into the mechanisms of vaginal niche establishment.     

A streptococcal NRAMP homologue is crucial for the survival of Streptococcus agalactiae under low pH conditions

Streptococcus agalactiae or Group B Streptococcus (GBS) is a commensal bacterium of the human gastrointestinal and urogenital tracts as well as a leading cause of neonatal sepsis, pneumonia and meningitis. Maternal vaginal carriage is the main source for GBS transmission and thus the most important risk factor for neonatal disease. Several studies in eukaryotes identified a group of proteins natural resistance‐associated macrophage protein (NRAMP) that function as divalent cation transporters for Fe²⁺ and Mn²⁺ and confer on macrophages the ability to control replication of bacterial pathogens. Genome sequencing predicted potential NRAMP homologues in several prokaryotes. Here we describe for the first time, a pH‐regulated NRAMP Mn²⁺/Fe²⁺ transporter in GBS, designated MntH, which confers resistance to reactive oxygen species (ROS) and is crucial for bacterial growth and survival under low pH conditions. Our investigation implicates MntH as an important colonization determinant for GBS in the maternal vagina as it helps bacteria to adapt to the harsh acidic environment, facilitates bacterial adherence, contributes to the coexistence with the vaginal microbiota and plays a role in GBS intracellular survival inside macrophages.     

妊娠妇女阴道微生态和B族链球菌与胎膜早破及母婴结局的相关性

探讨妊娠妇女阴道微生态状况和B族链球菌（GBS）感染与妊娠晚期胎膜早破及母婴结局的相关性。

回顾性收集2021年1月至2022年12月我院114例临床确诊足月胎膜早破妊娠妇女为研究对象（胎膜早破组）,随机选取同期分娩的129例健康妊娠妇女为对照组。收集两组对象临床资料,比较两组对象阴道微生态变化、GBS感染及不良母婴结局发生情况。

两组妊娠妇女阴道假丝酵母菌菌体及孢子检出情况比较差异均无统计学意义（均P＞0.05）。胎膜早破组患者阴道pH≥4.5、细菌性阴道病、需氧菌性阴道炎的发生率及微生态失衡率高于对照组（均P＜0.05）。胎膜早破组妊娠妇女绒毛膜羊膜炎、产褥感染、胎儿窘迫及新生儿肺炎等不良母婴结局发生率高于对照组（均P＜0.05）。单因素分析结果显示,阴道pH≥4.5、有GBS感染、阴道微生态失调与不良母婴结局有关（均P＜0.05）。

妊娠晚期阴道微生态失衡、GBS感染与妊娠晚期胎膜早破的发生相关,同时会增加不良母婴结局的发生率。加强相关危险因素的干预可降低妊娠晚期女性胎膜早破发生率,改善不良母婴结局。

     

Prevalence and significance of vaginal group B streptococcus colonization in pregnant women from Osijek, Croatia

The aim of the study was to determine the prevalence of vaginal group B streptococcus (GBS) colonization in pregnant women from Osijek area, the possible effect of GBS colonization on pregnancy outcome and neonatal complications and the role of intrapartum prophylaxis in this context. This retrospective case-control study took place at the Department of Gynecology and Obstetrics, Osijek University Hospital Center from December 2003 to June 2006. A total of 118 pregnant women was enrolled in study and divided into two groups: 59 women in 35th-37th week of gestation, free from risk factors for infection (control group); and 59 women in 25th-41st week of gestation with risk factors for infection. Low vaginal swab for GBS isolation and identification on selective and enriched medium was obtained from each woman. GBS colonization was recorded in 29 (24.6%) women: 12 (20.3%) control and 17 (28.8%) women at risk of infection, yielding a statistically non-significant difference (Chi2 = 1.480489; p < 0.48). Early neonatal infection was observed in six (20.7%) neonates born to 29 mothers with GBS colonization, pointing to a correlation between vaginal GBS colonization and early neonatal infection (r(s) = 0.99). Early perinatal infection was found in 22 (18.6%) neonates, including 17 (28.8%) pregnancies with risk factors, pointing to a significant correlation between vaginal GBS colonization, risk factors and early perinatal infection (Chi2 = 88.68; p < 0.001); however, gestational age and pregnancy outcome were not influenced by GBS colonization. In eight (36.4%) newborns, early neonatal infection developed in spite of intrapartum administration of antibiotics; three of these children were born to GBS positive mothers, and perinatal GBS infection was demonstrated in one (0.84%) child. Study results revealed a relatively high rate of GBS colonization in the population of pregnant women in Croatia, occasionally leading to early neonatal infection. Large studies are needed to develop national strategy for the prevention of GBS infection in Croatia.     

Alterations in the gut microbiota of patients with acquired immune deficiency syndrome

Acquired immune deficiency syndrome (AIDS), caused by infection with human immunodeficiency virus (HIV), is associated with gastrointestinal disease, systemic immune activation and changes in the gut microbiota. Here, we aim to investigate the gut microbiota patterns of HIV‐infected individuals and HIV‐uninfected individuals in populations from South China. We enrolled 33 patients with HIV (14 participants treated with highly active antiretroviral therapy [HAART] for more than 3 months; the remaining 19 individuals had not received treatment) and 35 healthy controls (HC) for a cross‐sectional comparison of gut microbiota using stool samples. Gut microbial communities were profiled by sequencing the bacterial 16S rRNA genes. Dysbiosis was more common among patients with AIDS compared with healthy individuals. Dysbiosis was characterized by decreased α‐diversity, low mean counts of Bacteroidetes, Faecalibacterium, Prevotella, Bacteroides vulgatus, Dialister and Roseburia inulnivorans, and high mean counts of Proteobacteria, Enterococcus, Streptococcus, Lactobacillus, Lachnociostridium, Ruminococcus gnavus and Streptococcus vestibularis. Increased abundance of Bacilli was observed in homosexual patients. Proteobacteria were higher among heterosexual patients with HIV infections. Tenericutes were higher among patients with history of intravenous drug abuse. Restoration of gut microbiota diversity and a significant increase in abundance of Faecalibacterium, Blautia and Bacteroides were found in patients receiving HAART compared to those who did not receive. HIV infection‐associated dysbiosis is characterized by decreased levels of α‐diversity and Bacteroidetes, increased levels of Proteobacteria and the alterations of gut microbiota correlate with the route of HIV transmission. The imbalanced faecal microbiota of HIV infection is partially restored after therapy.     

Vaginal Microbiome Characterization of Nellore Cattle Using Metagenomic Analysis

Understanding of microbial communities inhabiting cattle vaginal tract may lead to a better comprehension of bovine physiology and reproductive health being of great economic interest. Up to date, studies involving cattle microbiota are focused on the gastrointestinal tract, and little is known about the vaginal microbiota. This study aimed to investigate the vaginal microbiome in Nellore cattle, heifers and cows, pregnant and non-pregnant, using a culture independent approach. The main bacterial phyla found were Firmicutes (~40–50%), Bacteroidetes (~15–25%) and Proteobacteria (~5–25%), in addition to ~10–20% of non-classified bacteria. 45–55% of the samples were represented by only ten OTUs: Aeribacillus, Bacteroides, Clostridium, Ruminococcus, Rikenella, Alistipes, Bacillus, Eubacterium, Prevotella and non-classified bacteria. Interestingly, microbiota from all 20 animals could be grouped according to the respiratory metabolism of the main OTUs found, creating three groups of vaginal microbiota in cattle. Archaeal samples were dominated by the Methanobrevibacter genus (Euryarchaeota, ~55–70%). Ascomycota was the main fungal phylum (~80–95%) and Mycosphaerella the most abundant genus (~70–85%). Hormonal influence was not clear, but a tendency for the reduction of bacterial and increase of archaeal populations in pregnant animals was observed. Eukaryotes did not vary significantly between pregnant and non-pregnant animals, but tended to be more abundant on cows than on heifers. The present work describes a great microbial variability in the vaginal community among the evaluated animals and groups (heifers and cows, pregnant and non-pregnant), which is significantly different from the findings previously reported using culture dependent methods, pointing out the need for further studies on this issue. The microbiome found also indicates that the vaginal colonization appears to be influenced by the gastrointestinal community.     

Influence of sexual intercourse on genital tract microbiota in infertile couples

Several studies have suggested the association of disturbed genital tract microbiota with infertility. Our aim was to clarify the influence of sexual intercourse on partner’s genital tract microbiota in infertile couples. Seventeen couples were studied, and in 5 men inflammatory prostatitis (IP) was diagnosed. Semen samples were collected during menstruation of the female counterpart, two self-collected vaginal samples were taken 3–5 days later – before intercourse and 8–12 h after intercourse. Ureaplasma parvum was found in 59% of women, its prevalence was higher in women whose partner had IP, as well as in half of their male partners. Sexual intercourse caused significant shifts in vaginal microbiota – increase of Nugent score and shifts in cultured microbiota (emergence and disappearance of several species). These changes were less expressed in the presence of normal vaginal microbiota but more prominent in the partners of IP men. These changes may interfere with fertilization.     

Synergistic Effect Between Two Bacteriocin-like Inhibitory Substances Produced by Lactobacilli Strains with Inhibitory Activity for <Emphasis Type="Italic">Streptococcus agalactiae</Emphasis>

Group B streptococci (GBS) are bacterial species that colonize the vagina in pregnant women and as such may cause serious infections in neonates that passed through the birth channel. The objective of this work was to study the inhibitory activities produced by each bacteriocin-like inhibitory substance (BLIS) of Lactobacillus rhamnosus L60 and Lactobacillus fermentum L23, and the effects of the combined BLIS-es of these lactobacilli on GBS. The interactions between the BLIS-es were assessed by qualitative and quantitative methods on agar plates. The minimum inhibitory concentrations (MICs) and fractional inhibitory concentrations (FICs) were determined by a modification of the broth microdilution and checkerboard methods, respectively. Antibiotic susceptibilities of all S. agalactiae strains were assayed and the results of these tests were evaluated for statistical significance. A 7.5% of GBS isolates were recovered from 760 pregnant women and 91% of those strains were susceptible to each BLIS produced by L. fermentum, L. rhamnosus, and also to a mixture of them. The comparisons among the BLIS-es showed statistically significant differences, with a combination of the BLIS-es from the two Lactobacillus species being better than the BLIS of each one alone (P < 0.05) as GBS growth inhibitors. Synergistic activities between the BLIS-es were found on 100% of susceptible GBS strains, MICs ranges of BLIS of L23 and L60 were 80–160 and 160–320 UA ml⁻¹, respectively. By the checkerboard method, the BLIS-es combination showed synergistic effect on all sensitive strains tested, with values of FICs ranging from 0.131 to 0.218. The BLIS-es produced by these lactobacilli of vaginal origin were able to inhibit S. agalactiae isolates. The results indicate that these strains may have probiotic potential for the control of GBS in women and may consequently prevent GBS infections in newborns.     

Investigation of Supragingival Plaque Microbiota in Different Caries Status of Chinese Preschool Children by Denaturing Gradient Gel Electrophoresis

This study aimed to detect differences in the richness of total supragingival plaque microbiota as well as the species composition of oral streptococci involved in the different stages of dental caries. Forty-five plaque samples were collected from caries-moderate (CM, 4 ≤ dmfs ≤ 6), caries-susceptible (CS, dmfs ≥ 10), and age-matched caries-free children separately. Total DNA was isolated directly from each sample, and polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) analyses using universal and primers specific for oral streptococci were carried out. Using 16S rDNA PCR-DGGE, 34 different species of bacteria were identified in a culture-independent manner and classified into 11 genera according to phylogenetic analysis. Among them, Mitis group streptococci and Campylobacter, which were present in health status, no longer appeared in caries-susceptible samples. In addition, Capnocytophaga, Burkholderia, and Prevotella were found significantly less frequently in the CS group samples (P < 0.05), while there were no significant differences among the prevalence of Neisseria, Leptotrichia, Haemophilus, Mutans group streptococci, Corynebacterium, and Actinomyces in the three groups. Further DGGE analysis of rnpB gene amplicons obtained with oral streptococci species-specific primers showed that a total of 23 species of oral streptococci were identified. Streptococcus sanguinis, Streptococcus mitis, and Streptococcus oralis showed a significantly higher prevalence in healthy children (P < 0.05), while that of Streptococcus mutans and Streptococcus sobrinus did not vary among the three groups. Overall, these results suggest that supragingival plaque microbiota as a whole undergoes a more complicated shift in the caries process.     

Mutagenesis of a bacteriophage lytic enzyme PlyGBS significantly increases its antibacterial activity against group B streptococci

Group B streptococci (GBS) are the leading cause of neonatal meningitis and sepsis worldwide. Intrapartum antibiotic prophylaxis (IAP) is the current prevention strategy given to pregnant women with confirmed vaginal GBS colonization. Due to antibiotic resistance identified in GBS, we previously developed another strategy using a bacteriophage lytic enzyme, PlyGBS, to reduce vaginal GBS colonization. In this study, various DNA mutagenesis methods were explored to produce PlyGBS mutants with increased lytic activity against GBS. Several hyperactive mutants were identified that contain only the endopeptidase domain found in the N-terminal region of PlyGBS and represent only about one-third of the wild-type PlyGBS in length. Significantly, these mutants not only have 18–28-fold increases in specific activities compared to PlyGBS, but they also have a similar activity spectrum against several streptococcal species. One of the hyperactive mutants, PlyGBS90-1, reduced the GBS colonization from >5 logs of growth per mouse to <50 colony-forming units (cfu) 4 h post treatment (∼4-log reduction) using a single dose in a mouse vaginal model. A reduction in GBS colonization before delivery should significantly reduce neonatal GBS infection providing a safe alternative to IAP.     

分娩方式对北京地区持续母乳喂养的34周龄婴儿肠道菌群影响

[目的] 比较持续母乳喂养条件下不同分娩方式的34周龄婴儿肠道菌群差异,探讨分娩方式对较大婴儿肠道菌群发育的影响。[方法] 在北京地区招募健康足月分娩母乳喂养婴儿,在34周仍然参与随访的持续母乳喂养婴儿共21例,其中剖宫产婴儿16例、阴道分娩婴儿5例,进行肠道菌群的16S rRNA检测。[结果] 两组共21个粪便样本中,共注释到6个门,分别为：疣微菌门、变形菌门、梭杆菌门、厚壁菌门、放线菌门和拟杆菌门;两组共21个样本中共有57个OTU注释到属水平,其中,26个属水平OTU被注释到厚壁菌门,18个属水平OTU被注释到变形菌门,6个属水平OTU被注释到放线菌门,5个属水平OTU被注释到拟杆菌门,梭杆菌门、疣微菌门各有1个属水平OTU被注释。其中变形菌门在阴道分娩组（44.17%）肠道菌群中的含量高于剖宫产组（16.10%）;而放线菌门在阴道分娩婴儿（0.00%）肠道菌群中的含量低于剖宫产婴儿（0.09%）。阴道分娩组与剖宫产组相比,共有7个菌属的丰度发生了显著降低（P<0.05）,分别为副杆菌属、葡萄球菌属、嗜血杆菌属、乳杆菌属、肠球菌属、双歧杆菌属及一注释到科水平的毛螺旋菌科OTU。[结论] 分娩方式对持续母乳喂养的婴儿肠道菌群结构存在影响,且这种影响在出生后34周仍然存在。     

Occurrence of surface protein genes from alpha-like protein (Alp) family in Streptococcus agalactiae isolates

Distribution of serotypes and alpha-like surface protein (Alp) of Streptococcus agalactiae (Group B Streptococci - GBS) vary with geographical region, ethnic origin and the virulence of clinical isolates. Demonstration of different genotypes based on surface protein genes improves the potential of GBS subtyping, is essential in research on new vaccines against invasive neonatal infections and may be useful in epidemiological studies. The molecular characterization of protein gene profile of GBS isolates was the main aim of this study. We evaluated the applicability of multiplex PCR for the identification of GBS protein genes from Alp family, such as: epsilon, bca, rib, alp2, alp3, alp4 and evaluated presence of these genes in the group of GBS isolates originating from vaginal or rectal carriage in pregnant women. For statistical analysis the G2 (Likelihood ratio) test was used. P values of < 0.05 were considered significant. The surface protein genes were found in all investigated strains. The epsilon gene dominated (27%) in GBS isolates originating from healthy pregnant women. The other genes were detected with the following frequency: rib (21%), alp2 (21%), bca (17%) and alp3 (14%). In the analyzed population, GBS strains with alp4 gene were not found. A statistically significant relationship between surface protein genes and capsular polysaccharides was demonstrated (p < 0.0001). The results of our study show immense diagnostic usefulness of multiplex PCR for identification of genes encoding GBS surface proteins from Alp family.     

Pattern of infection and antibiotic activity among Streptococcus agalactiae isolates from adults in Mashhad,Iran

Background:

One of the main causes of sexually transmitted diseases is group B β- hemolytic streptococci (GBS) multiplying in the genital tracts. Penicillin is the most common drug for the treatment of infections caused by these bacteria, but in patients suffering from Penicillin allergy, Erythromycin and Clindamycin are used as alternative therapeutic drugs against GBS. Recently, resistance to these drugs has been reported more often. In this study, efforts have been made to determine the prevalence and antibiotic resistance of GBS.

Methods:

Modified Christie Atkins Munch-Petersen (CAMP) test was conducted on over 2400 samples of urine and discharge taken from vagina, urethra and prostate. The drug sensitivity was performed by double disk sensitivity tests to Bacitracin, Trimethoprim, and Sulfamethoxazole and then the resistant samples were investigated by E-test to determine the minimal inhibitory concentrations (MICs) value.

Results:

Twenty-three vaginal and 10 urethral discharge, 27urine and 6 prostatic secretion samples were GBS positive. The most symbiotic microorganisms with GBS were strains of Enterococci (90%), Staphylococcus saprophyticus (25%) and Candida albicans (6%). The disk diffusion method showed 18 cases with Penicillin resistance (MIC: 1.5 mg/ml).

Conclusion:

Taken together, GBS carriers’ rate in this study was found 20.65% (8.24% men and 12.4% women). Furthermore, findings showed high-level resistance to Erythromycin and Clindamycin.Key Words: Antibiotic resistance, Genitourinary system, Streptococcus agalactiae, minimal inhibitory concentration (MIC)     

羊膜腔内感染微生物分布及相关影响因素分析

研究剖宫产术中产妇的感染症状、羊水微生物分布情况及相关影响因素,为该类患者的治疗提供帮助。

采集本院2020年6月至2023年2月于剖宫产术中提取的羊水498份进行细菌培养,根据羊水微生物分布情况和相关因素,综合分析产妇临床感染症状。

498份送检羊水标本中有147份标本检出微生物,总检出率为29.5%（147/498）。498例产妇中有100例术前出现感染症状,检出微生物78株;51例术后出现感染症状,检出微生物34株;8例术后切口感染,检出微生物7株。339例没有临床感染症状的产妇检出微生物28株。羊水微生物的检出率与胎膜早破或试产后人工破膜、产妇自身阴道菌群分布、术前出现感染症状呈显著相关（均P＜0.05）。

对胎膜早破、阴道菌群失调等高危产妇及时送检标本查找病原体,对羊膜腔内感染的早期预防和针对性治疗具有显著意义。