Palmer A L, Leos N K, Hall M, Jackson G L, Sánchez P J
Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235, USA.
Am J Perinatol. 1996 May;13(4):235-9. doi: 10.1055/s-2007-994371.
Our objective was to determine whether urine collection by suprapubic bladder aspiration (SBA) improves the specificity of the group B streptococcal (GBS) latex agglutination (LA) test by avoiding contamination of urine with GBS from perineal and rectal colonization that can result in a positive LA test in an uninfected infant when the urine is collected by bag. Part 1 consists of a retrospective review of the medical records of 113 infants who had urine collected by SBA for GBS LA testing as part of evaluation for possible sepsis. The sensitivity and specificity of the urine LA test was assessed by comparing it with blood culture results. In part 2, a prospective analysis was performed of 19 newborns who had rectal and vaginal/penile cultures as well as urine by SBA and bag for GBS cultures and LA. Results of LA testing on urine collected by both of these methods were compared with results of urine, perineal, and rectal cultures. In the retrospective review of GBS LA testing performed on 113 consecutive urine specimens collected by SBA from neonates being evaluated for suspected sepsis, the sensitivity and specificity were 67% and 89%, respectively, when compared with blood culture results. Twelve infants who had a positive LA test result but a sterile blood culture (BC-,LA+) were compared with 95 infants with both blood cultures and urine LA tests negative for GBS (BC-, LA-). BC-, LA+ infants were more likely than those with BC-, LA- to have an immature to total neutrophil (I/T) ratio > or = 0.16 at 12 and 24 hours (p = 0.04 and 0.02, respectively). In the prospective study, we found that a positive GBS LA test can be due to perineal contamination and possibly to gastrointestinal absorption of GBS antigen. No false positive LA test results occurred on urine obtained by SBA; however, use of this method failed to detect the one infant with GBS bacteremia. Because of suboptimal sensitivity and specificity, use of the GBS LA test on urine obtained either by SBA or bag cannot be recommended for diagnosis of early onset GBS disease.
我们的目标是确定经耻骨上膀胱穿刺抽吸（SBA）采集尿液是否能通过避免会阴和直肠定植的B族链球菌（GBS）污染尿液来提高GBS乳胶凝集（LA）试验的特异性，因为当通过尿袋采集尿液时，这种污染会导致未感染婴儿的LA试验呈阳性。第1部分包括对113例婴儿的病历进行回顾性分析，这些婴儿因可能患有败血症而接受评估，通过SBA采集尿液进行GBS LA检测。通过将尿液LA试验结果与血培养结果进行比较，评估尿液LA试验的敏感性和特异性。在第2部分中，对19例新生儿进行了前瞻性分析，这些新生儿接受了直肠和阴道/阴茎培养，以及通过SBA和尿袋采集尿液进行GBS培养和LA检测。将这两种方法采集的尿液的LA检测结果与尿液、会阴和直肠培养结果进行比较。在对113例因疑似败血症而接受评估的新生儿通过SBA连续采集的尿液标本进行GBS LA检测回顾性分析中，与血培养结果相比，敏感性和特异性分别为67%和89%。将12例LA试验结果为阳性但血培养无菌（BC-，LA+）的婴儿与95例血培养和尿液LA试验均为GBS阴性（BC-，LA-）的婴儿进行比较。BC-，LA+婴儿在12小时和24小时时未成熟中性粒细胞与总中性粒细胞（I/T）比值≥0.16的可能性高于BC-，LA-婴儿（分别为p = 0.04和0.02）。在前瞻性研究中，我们发现GBS LA试验阳性可能是由于会阴污染以及GBS抗原可能通过胃肠道吸收所致。通过SBA采集的尿液未出现LA试验假阳性结果；然而，使用这种方法未能检测出1例患有GBS菌血症的婴儿。由于敏感性和特异性欠佳，不建议对通过SBA或尿袋采集的尿液进行GBS LA试验来诊断早发型GBS疾病。
