中段尿培养检出B群链球菌的临床意义

Clinical significance of detecting group B Streptococcus from midstream urine culture

目的 探讨中段尿培养中分离出B群链球菌(GBS)的临床意义和耐药性,旨在为临床尿路感染诊治提供依据。方法 通过实验室信息系统搜索2020年2月—2022年12月南京某医院住院和门诊患者中段尿培养分离出GBS的菌株信息,筛选资料完整者,查阅病例资料、尿常规及药敏试验结果。结果 中段尿培养标本共检出非重复细菌9 081株,其中GBS 425株,占比4.7%,位列第6。剔除资料不完整者,共纳入365例患者进行研究。其中男性169例(46.3%),女性196例(53.7%),平均年龄(55.4±15.2)岁。365例检出GBS的患者来源于17个科室,泌尿外科(237例,64.9%)占比最高。患者基础疾病主要包括高血压病136例,糖尿病95例,泌尿系统结石120例,泌尿系统肿瘤98例;211例患者接受了泌尿系统手术,术前均使用了抗菌药物,205例在术后留置导尿管;9例在妊娠中晚期尿液中检出GBS。GBS菌落计数≤10^(4)CFU/mL占36.4%(133例),10^(4)~10^(5)CFU/mL占38.9%(142例),≥10^(5)CFU/mL占24.7%(90例)。有尿路感染症状的患者占24.9%(91例),无症状性菌尿患者占75.1%(274例)。男性中有尿路感染症状者低于女性(19.5%VS 29.6%,P<0.05)。随着尿培养GBS菌落计数增加,有尿路感染症状的患者比例呈升高趋势(P<0.05)。尿培养送检当日尿常规白细胞、白细胞酯酶、亚硝酸盐阳性比率分别为53.2%、50.1%、3.8%。有症状尿路感染患者中尿潜血、白细胞酯酶、白细胞、尿蛋白的阳性率均高于无症状性菌尿患者(均P<0.05)。未发现GBS对青霉素、氨苄西林、万古霉素、利奈唑胺、替加环素耐药,对左氧氟沙星、莫西沙星耐药率在40%左右,对四环素、克林霉素耐药率>60%。结论 尿液中分离出GBS在非妊娠成人中比较常见,有尿路感染症状者仅占少数。尿培养、尿常规结果应结合患者临床症状、体征综合判断。尿液中GBS对多种抗菌药物敏感,临床应根据药敏结果合理用药。

Objective To explore the clinical significance and antimicrobial resistance of group B Streptococcus(GBS)isolated from midstream urine culture,aiming to provide a basis for the diagnosis and treatment of clinical urinary tract infection(UTI).Methods Information about GBS strains isolated from midstream urine culture of inpatients and outpatient in a hospital in Nanjing from February 2020 to December 2022 were retrieved through laboratory information system,strains with complete data were screened out.Case data,urine routine,and antimicrobial susceptibility testing results were reviewed.Results A total of 9081 non-repetitive bacterial strains were detected from midstream urine culture,including 425 GBS strains,accounting for 4.7%,ranking sixth.Strains with incomplete data were excluded,a total of 365 patients were included in the study.169(46.3%)were males and 196(53.7%)were females,with an average age of(55.4±15.2)years.365 patients who were detected GBS were from 17 departments,with the highest proportion being department of urology(n=237,64.9%).The underlying diseases of patients mainly included hypertension(n=136),diabetes(n=95),urolithiasis(n=120)and urinary tumors(n=98).211 patients underwent urological surgery,all were treated with antimicrobial agents before surgery,and 205 patients underwent indwelling urinary catheters after surgery;9 patients were detected GBS from urine during the middle and advanced stage of pregnancy.36.4%(n=133),38.9%(n=142)and 24.7%(n=90)patients had GBS colony count≤10^(4) CFU/mL,10^(4)-10^(5) CFU/mL,and≥10^(5) CFU/mL,respectively.Patients with symptoms of UTI accounted for 24.9%(n=91),and asymptomatic bacteriuria accounted for 75.1%(n=274).The incidence of UTI symptoms in males was lower than that in females(19.5%vs 29.6%,P<0.05).As the GBS colony count in urine culture increased,the proportion of patients with symptoms of UTI showed an upward trend(P<0.05).On the day of urine culture,the positive rates of urine routine white blood cells,leukocyte esterase,and nitrite were 53.2%,50.1%,and 3.8%,respectively.The positive rates of urine occult blood,leukocyte esterase,white blood cells,and urine protein in patients with symptomatic UTI were all higher than those with asymptomatic bacteriuria patients(all P<0.05).No GBS were found to be resistant to penicillin,ampicillin,vancomycin,linezolid,and tigecycline.The resistance rate to levofloxacin and moxifloxacin was about 40%,and resistance rate to tetracycline and clindamycin was over 60%.Conclusion GBS isolated from urine is more common in non-pregnant adults,and only a small percentage have symptoms of UTI.The results of urine culture and urine routine should be comprehensively judged based on patient’s clinical symptoms and signs.GBS in urine is susceptible to multiple antimicrobial agents,and clinical medication should be adopted rationally based on antimicrobial susceptibility testing result.