Saha Samir K, Darmstadt Gary L, Yamanaka Noboru, Billal Dewan S, Nasreen Tania, Islam Maksuda, Hamer Davidson H
Department of Microbiology, Bangladesh Institute of Child Health, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh.
Pediatr Infect Dis J. 2005 Dec;24(12):1093-8. doi: 10.1097/01.inf.0000190030.75892.78.
Streptococcus pneumoniae is the leading cause of childhood pneumonia and meningitis worldwide. Isolation of this organism, however, is uncommon in resource-poor countries, in part because of extensive use of prior antibiotics. A rapid, highly sensitive immunochromatographic test (ICT) for S. pneumoniae was evaluated for the diagnosis of meningitis.
Cerebrospinal fluid (CSF) from 450 children with suspected meningitis was tested with ICT, and results were compared with CSF culture, latex agglutination test (LAT) and/or polymerase chain reaction (PCR). Serial CSF specimens from 11 patients were also evaluated for duration of positive results during effective antimicrobial therapy.
All 122 cases of pyogenic pneumococcal meningitis positive either by culture (N = 87) or PCR (N = 35) were positive by ICT, yielding 100% (122 of 122) sensitivity. All purulent CSF specimens from patients with meningitis caused by other bacteria by culture (N = 149) or by LAT (N = 48) or those negative by culture, LAT and LytA and thus of unknown etiology (N = 20), and normal CSF specimens (N = 104) were negative by ICT. Thus the specificity of ICT also was 100% (321 of 321), although negativity of ICT was not confirmed by PCR, if it was positive for other organisms either by culture or LAT. Serotyping of S. pneumoniae strains revealed 28 different serotypes, indicating that outcome of ICT are independent of diverse capsular serotype of pneumococcus. Antigen was detected by ICT for at least 10 days after presentation, and 1 was still positive on day 20, which was longer than for either LAT or PCR.
ICT for pneumococcal antigen in CSF is 100% sensitive and specific in diagnosing pyogenic pneumococcal meningitis and can detect approximately 30% more pneumococcal meningitis cases than with culture alone. The simplicity of the test procedure and the longevity of CSF antigen detection suggest the potential utility of ICT to estimate the true burden of pneumococcal disease, as for Haemophilus influenzae type b using data from meningitis, and to guide selection of appropriate antibiotic treatment, especially in resource-poor countries with widespread prehospital antimicrobial use.
肺炎链球菌是全球儿童肺炎和脑膜炎的主要病因。然而，在资源匮乏的国家，分离出这种病原体的情况并不常见，部分原因是此前广泛使用抗生素。对一种用于肺炎链球菌的快速、高灵敏度免疫层析试验（ICT）进行了评估，以用于脑膜炎的诊断。
对450例疑似脑膜炎儿童的脑脊液（CSF）进行ICT检测，并将结果与脑脊液培养、乳胶凝集试验（LAT）和/或聚合酶链反应（PCR）进行比较。还对11例患者的系列脑脊液标本进行了评估，以观察有效抗菌治疗期间阳性结果的持续时间。
通过培养（n = 87）或PCR（n = 35）确诊的所有122例化脓性肺炎球菌脑膜炎病例经ICT检测均呈阳性，灵敏度达100%（122/122）。所有由其他细菌引起的脑膜炎患者的脓性脑脊液标本，通过培养（n = 149）或LAT（n = 48）确诊，或培养、LAT和LytA检测均为阴性因而病因不明的标本（n = 20），以及正常脑脊液标本（n = 104），经ICT检测均为阴性。因此，ICT的特异性也为100%（321/321），不过如果通过培养或LAT检测其他病原体呈阳性，ICT检测结果为阴性时未通过PCR进行确认。肺炎链球菌菌株的血清分型显示有28种不同血清型，这表明ICT的结果与肺炎球菌不同的荚膜血清型无关。在出现症状后至少10天通过ICT可检测到抗原，有1例在第20天时仍呈阳性，这比LAT或PCR检测的持续时间更长。
用于检测脑脊液中肺炎球菌抗原的ICT在诊断化脓性肺炎球菌脑膜炎方面灵敏度和特异性均为100%，与单独培养相比，能多检测出约30%的肺炎球菌脑膜炎病例。检测过程的简便性以及脑脊液抗原检测的持久性表明，ICT有可能像利用脑膜炎数据估算b型流感嗜血杆菌疾病真实负担那样，用于估算肺炎球菌疾病的真实负担，并指导选择合适的抗生素治疗，尤其是在院前广泛使用抗菌药物的资源匮乏国家。
