Résumé
Objective:To investigate the phenotypes, molecular types and drug-resistance genes of erythromycin (ERY)-resistant group B Streptococcus (GBS) in pregnant women in late pregnancy in Zhengzhou and provide basic data for the prevention, control and treatment of GBS infection. Methods:This study retrospectively collected 86 GBS strains isolated from the vaginal secretions of pregnant women in late pregnancy at Maternal and Child Health Hospital of Henan Province from 2021 to 2022. ERY-resistant GBS strains were selected using the ERY disk diffusion method, and their susceptibility to 10 different antibiotics was tested. Whole-genome sequencing was performed to analyze their molecular features including molecular types, clonal complex groups and drug-resistance genes. Drug-resistance genes carried by GBS strains belonging to different clonal complex groups were compared.Results:There were 70 ERY-resistant GBS strains. Among them, 7.14%(5/70) exhibited an inducible resistance phenotype to macrolide-lincosamide-streptogramin B (MLSB) antibiotics; 84.29%(59/70) showed constitutive resistance to MLSB antibiotics; 8.57%(6/70) were resistant to macrolides but susceptible to lincosamides. The resistance rates of these strains to clindamycin (CLI), tetracycline (TE) and levofloxacin (LEV) were 91.43%(64/70), 54.29%(38/70) and 60.00%(42/70), respectively. These ERY-resistant strains exhibited multidrug resistance patterns with 40.00%(28/70) showing ERY-CLI-LEV resistance phenotype and 30.00%(21/70) showing ERY-CLI-TE resistance phenotype. The major drug-resistance genes carried by the 70 GBS strains were macrolide/lincosamide resistance genes mreA (100.00%) and ermB (53/70, 75.71%), aminoglycoside resistance genes ant (6)-Ⅰ a (22/70, 31.43%) and aph(3′)-Ⅲ (18/70, 25.71%), and tetracycline resistance genes tetM (22/70, 31.43%) and tetO (13/70, 18.57%). These strains belonged to 12 sequence types derived from seven clonal complexes (CCs) and 48.57%(34/70) of them were clustered into CC12. All CC12 strains harbored ermB, but none carried ermA. The positive rates of lsaE, lunB, and aac (6′)- aph(2" ) in CC19 and CC651 strains, ant (6)-Ⅰ a in CC651 and CC452 strains, and mefA and msrD in CC19 and CC23 strains were significantly higher than those in CC12 strains ( P<0.001). Conclusions:ERY-resistant GBS in Zhengzhou exhibited diverse drug resistance phenotypes and molecular types. CC12 was the most prevalent clonal complex in this region. The constitutive MLSB resistance phenotype and ermB gene were the most common ERY resistance phenotype and genotype, respectively, and tetM gene was related to tetracycline resistance. Furthermore, the drug-resistance genes varied in GBS strains of different clonal complexes. This study suggested that close attention should be paid to the epidemiological situation of GBS in this region and the effectiveness of antibiotics used for clinical prevention and treatment of GBS infection should be carefully evaluated.
Résumé
Objective:To investigate the clinical characteristics of Guillain-Barré syndrome (GBS) combined with hyponatremia in Southern China and its risk factors for prognosis.Methods:The retrospective cohort study involved patients who met the diagnostic criteria of GBS from 18 upper first-class hospitals of 6 provinces/cities in southern China (south of Huaihe River) from January 1, 2013 to September 30, 2016. The clinical data of these patients were collected. According to serum sodium levels, they were divided into hyponatremia group (serum sodium concentration<135 mmol/L) and normal serum sodium group (serum sodium concentrations≥135 mmol/L). Based on Medical Research Coucil sum scores at nadir, these patients were divided into mild GBS group (>40), moderate GBS group (30-40), and severe GBS group (<30). Furthermore, according to the Hughes GBS disability scale (H-GBS-DS) scores at discharge, these GBS patients with hyponatremia were divided into favorable prognosis group (H-GBS-DS<3) and poor prognosis group (H-GBS-DS≥3). The incidence of hyponatremia in patients from the mild GBS group, moderate GBS group, and severe GBS group were compared. Multivariate Logistic regression analysis was performed to determine the clinical risk factors for hyponatremia in GBS patients. The clinical data of hyponatremia patients from favorable prognosis group and poor prognosis group were compared; multivariate Logistic regression analysis was used to determine the risk factors for poor prognosis in GBS patients with hyponatremia.Results:(1) Among the 570 patients, 354 had mild GBS, 94 had moderate GBS, and 122 had severe GBS; 134 GBS patients were combined with hyponatremia, 436 GBS patients had normal serum sodium. The hyponatremia incidence in mild, moderate and severe GBS groups increased successively, ( P<0.05). Multivariate Logistic regression analysis showed that facial paralysis ( OR=1.979, 95%CI: 1.172-3.342, P=0.011), respiratory muscle paralysis ( OR=3.218, 95%CI: 1.611-6.428, P=0.001), secondary pulmonary infection ( OR=4.822, 95%CI: 2.835-8.201, P=0.000), severe GBS ( OR=2.611, 95%CI: 1.444-4.721, P=0.001) and length of hospital stay ( OR=1.029, 95%CI: 1.009-1.050, P=0.004) were risk factors for hyponatremia in GBS patients. (2) Among 134 GBS patients with hyponatremia, 80 had poor prognosis and 54 had favorable prognosis. As compared with the favorable group, the poor prognosis group had significantly lower proportion of patients with extraocular muscle paralysis, statistically higher proportions of patients with respiratory muscle paralysis and secondary pulmonary infection, significantly different severities of GBS, signficantly higher proportion of patients accepted intravenous immunoglobulin (IVIG) and hormone treatments, statistically longer length of hospital stay ( P<0.05). Respiratory muscle paralysis ( OR=25.590, 95%CI: 9.433-69.423, P=0.000), moderate GBS ( OR=17.030, 95%CI: 8.441-34.361, P=0.000), and severe GBS ( OR=51.042, 95%CI: 24.596-105.926, P=0.000) were independent risk factors for poor short-term prognosis of GBS patients with hyponatremia. Conclusions:Severe GBS patients with facial paralysis, respiratory muscle palsy, secondary pulmonary infection, and long hospital stay trend to have hyponatremia. Hyponatremia patients with respiratory muscle paralysis and moderate/severe GBS have poor short-term prognosis.