Serotype distribution, antimicrobial resistance, and molecular characterization of group B Streptococcus isolates from Chinese pregnant woman.

OBJECTIVE: This study was aimed to investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of group B Streptococcus (GBS) in the Beijing area. METHODS: Lower vaginal and rectal swabs were obtained from pregnant women of 35-37 gestational weeks (GWs) who attended the Beijing Obstetrics and Gynecology Hospital. All GBS isolates were identified with Gram staining, catalase reaction assays, and CAMP tests, followed by antibiotic susceptibility testing, serotype identification, multilocus sequence typing and erythromycin resistance gene analysis (ermB and mefE). RESULTS: From July 2020 to June 2022, 311 (5.17%) of 6012 pregnant women that were screened for GBS colonization were detected positive. Of the eight serotypes identified (III, Ia, Ib, IV, II, VIII, V, and NT), serotypes III (43.09%), Ia (34.08%) and Ib (17.04%) were the predominant species. In the antimicrobial susceptibility experiments, the resistant rates measured for erythromycin, clindamycin, levofloxacin, and tetracycline were 76.21%, 63.99%, 50.80%, and 81.03%, respectively, and 7.6% of GBS isolates showed inducible clindamycin in resistance (D-test phenotype). Meanwhile, the multilocus sequence typing analysis showed that sequence type 19 (ST19) (30.34%) and ST10 (18.62%) were the dominant sequence types. Among the 237 erythromycin-resistant isolates, 176 harbored ermB (128, 54.00%) or mefE (48, 20.30%) gene alone. CONCLUSION: The infection rates, serotypes or MSLT distribution, and antimicrobial resistance of GBS in Beijing area were investigated, which may be applied in analyses of the epidemiological characteristics of GBS. This contributes to the basic knowledge required for successful GBS vaccine development suited for disease prevention and treatment in China, as well as the implementation of effective clinical antimicrobials.

Emergence of ST1193 Clone in Maternal and Neonatal ESBL-Producing E. coli Isolates.

Objective: The emerging epidemic of extended-spectrum ß-lactamase-producing E. coli (ESBL-EC) is a global public health crisis. ESBL-EC infections are increasing worldwide and contribute to morbidity and mortality among newborn infants. However, the antimicrobial resistance characteristics and clonal transmission of maternal and neonatal ESBL-EC isolates need to be further deciphered. Materials and Methods: We performed phenotypic and genotypic characterization of 33 ESBL-EC isolates from pregnant women and newborn during 2019-2020. Results: Minimum inhibitory concentrations of 17 antimicrobial agents showed that all isolates were multidrug-resistant (MDR) and had a resistance rate of 100% to ampicillin, and mild resistance to florfenicol, gentamicin, ceftazidime, and amoxicillin-clavulanate. Additionally, imipenem, meropenem, polymyxin, and tigecycline exhibited good activity against the tested ESBL-EC isolates with low MIC50 (0.06-1 µg/mL) and MIC90 (0.06-1 µg/mL). Whole genome sequencing indicated that ESBL-EC isolates contained diverse antimicrobial resistant genes (blaCTX-M, blaTEM, blaSHV, tetA, etc.) and toxin genes (ompA, csg, fimH, hybtA, etc.). blaCTX-M genes were the main ESBL genotype. ST1193 (18.2%) was the second most abundant ST among the ESBL-EC isolates (ST131 was the most common, with 30.3%), and this is the first report of its mother-to-infant colonization transmission in China. Conclusion: These findings revealed the occurrence of high-risk ST1193 clone among ESBL-EC isolates from pregnant women and newborn colonization in China. Further national or regional multicenter studies are needed to assess the dissemination and evolution of ESBL-EC ST1193 clone as a nosocomial pathogen in China.

Drug resistance characteristics and molecular typing of Escherichia coli isolates from neonates in class A tertiary hospitals: A multicentre study across China.

OBJECTIVES: Escherichia coli is a common pathogen causing invasive bacterial infections in neonates. In recent years, clinical antimicrobial susceptibility testing has demonstrated an increased rate of drug-resistant E. coli infections. This study aimed to analyse the resistance characteristics of E. coli against common antimicrobial agents, and perform multilocus sequence typing (MLST) in clinical strains of E. coli collected from Chinese neonates. METHODS: Culture-positive specimens of E. coli were collected from neonates in seven class A tertiary hospitals located in seven cities across different provinces in China between November 2019 and October 2020. E. coli isolated from these specimens were subjected to antimicrobial susceptibility testing (by broth microdilution method), extended-spectrum ß-lactamase (ESBL) detection, and MLST. RESULTS: A total of 223 E. coli strains were isolated, with an overall resistance rate of 87.4%, an ESBL-positive rate of 48.0%, and a multidrug resistance rate of 42.2%. Among the 20 antimicrobial agents tested, E. coli strains showed the highest resistance rates against cefotaxime (59.2%), trimethoprim/sulfamethoxazole (56.5%), doxycycline (39.9%), ciprofloxacin (36.8%), and aztreonam (31.0%). The resistance rates of E. coli strains isolated from children's hospitals against piperacillin/tazobactam, cefotaxime, ciprofloxacin, trimethoprim/sulfamethoxazole, and carbapenems, were significantly higher than those of strains isolated from maternity and child health hospitals. The primary E. coli multilocus sequence types were ST1193, ST95, ST73, ST410, and ST131. The ESBL production rates and multidrug resistance rates of ST1193, ST410, and ST131 were significantly higher than those of ST95 and ST73. Significantly, more strains of E. coli ST1193 and ST410 were isolated from children's hospitals than from maternity and child health hospitals. CONCLUSIONS: The rates of antimicrobial agent resistance in E. coli isolates from hospitalised neonates in China were high. The increased number of strains of E. coli ST1193 and ST410 was the reason for higher resistance rates to multiple antimicrobial agents in E. coli from children's hospitals compared with those from maternal and child health hospitals.

Current status of group B Streptococcus infection in neonates: a multicenter prospective study. / 新生儿Bæ—é“¾çƒèŒæ„ŸæŸ“çŽ°çŠ¶çš„å¤šä¸­å¿ƒå‰çž»æ€§ç ”ç©¶.

OBJECTIVES: To investigate the incidence of maternal group B Streptococcus (GBS) colonization and neonatal early-onset GBS disease (GBS-EOD), and to study the factors associated with the development of GBS-EOD in the offspring of pregnant women with GBS colonization. METHODS: A total of 16 384 pregnant women and 16 634 neonates delivered by them were enrolled prospectively who had medical records in Xiamen Maternal and Child Care Hospital, Beijing Obstetrics and Gynecology Hospital of Capital Medical University, and Zhangzhou Zhengxing Hospital from May 1, 2019 to April 30, 2020. Unified GBS screening time, culture method, and indication for intrapartum antibiotic prophylaxis (IAP) were adopted in the three hospitals. The incidence rates of maternal GBS colonization and neonatal GBS-EOD were investigated. A multivariate logistic regression analysis was used to identify the factors associated with the development of GBS-EOD in the offspring of pregnant women with GBS colonization. RESULTS: In these three hospitals, the positive rate of GBS culture among the pregnant women in late pregnancy was 11.29% (1 850/16 384), and the incidence rate of neonatal GBS-EOD was 0.96‰ (16/16 634). The admission rate of live infants born to the GBS-positive pregnant women was higher than that of those born to the GBS-negative ones (P<0.05). The live infants born to the GBS-positive pregnant women had a higher incidence rate of GBS-EOD than those born to the GBS-negative ones [6.38‰ (12/1 881) vs 0.27‰ (4/14 725), P<0.05]. The multivariate logistic regression analysis showed that placental swabs positive for GBS and positive GBS in neonatal gastric juice at birth were independent predictive factors for the development of GBS-EOD (P<0.05), while adequate IAP was a protective factor (P<0.05) in the offspring of pregnant women with GBS colonization. CONCLUSIONS: GBS colonization of pregnant women in late pregnancy has adverse effects on their offspring. It is important to determine prenatal GBS colonization status of pregnant women and administer with adequate IAP based on the indications of IAP to reduce the incidence of neonatal GBS-EOD. Citation.

LINC00943 is correlated with gastric cancer and regulates cancer cell proliferation and chemosensitivity via hsa-miR-101-3p.

BACKGROUND: Non-coding RNAs have emerged as important regulators in human cancers. In this work, we investigated the role of long intergenic non-protein-coding RNA 943 (LINC00943) in gastric cancer (GC). METHODS: LINC00943 expression was evaluated in GC patient tissues and cell lines. In SNU-5 and MKN-45 cells, LINC00943 was knocked down to investigate its roles in regulating GC cell proliferation, 5-FU chemosensitivity and in vivo explant growth. Possible downstream target of LINC00943, human mature microRNA-101-3p (hsa-miR-101-3p) was also evaluated. RESULTS: LINC00943 was aberrantly overexpressed in in situ GC tumors and immortal GC cell lines. LINC00943 overexpression was associated with GC patients' poor prognosis. LINC00943 knockdown reduced GC cell proliferation, 5-FU resistance and in vivo explant growth. Hsa-miR-101-3p was found to be regulated by LINC00943 in GC. Hsa-miR-101-3p downregulation reversed the tumor-suppressing functions of LINC00943 knockdown in GC cells. CONCLUSION: In summary, our results indicated that LINC00943 was correlated with gastric cancer and regulates cancer cell proliferation and chemosensitivity via hsa-miR-101-3p.

Detection of Candida species in pregnant Chinese women with a molecular beacon method.

Purpose. Candida pathogens are commonly found in women and can cause vulvovaginal candidiasis (VVC), whose infection rate is further increased during pregnancy. We aimed to study the Candida prevalence and strain distribution in pregnant Chinese women with a molecular beacon assay.Methodology. From March 2016 to February 2017, a total of 993 pregnant women attending routine antenatal visits at the Beijing Obstetrics and Gynecology Hospital were enrolled. For Candida detection and identification, a unique molecular beacon assay was presented and compared with a traditional phenotypic method. Antifungal susceptibility was tested with the following agents: 5-flucytosine, amphotericin B, fluconazole, itraconazole and voriconazole.Results. The prevalence of Candida was found to be 21.8 % when using the molecular method and 15.0 % when using the phenotypic method. The distribution of the Candida spp. was listed in order of decreasing prevalence: Candida albicans (79.8 %), Candida glabrata (13.5 %), Candida parapsilosis (3.7 %), Candida krusei (2.2 %) and Candida tropicalis (1.1 %). We found that 90.7 % of the Candida detection results were consistent between the molecular and the phenotypic methods. In the cases where the sequencing analyses for the Candida isolates resulted in inconsistent identification, the molecular method showed higher sensitivity than the phenotypic method (96.0 vs 64.6 %). C. albicans, C. glabrata and C. parapsilosis were essentially susceptible to all five antifungal agents tested, whereas C. tropicalis and C. krusei were susceptible to voriconazole and amphotericin B.Conclusion. By exhibiting good sensitivity and specificity, the molecular assay may offer a fast and accurate Candida screening platform for pregnant women.