Baron E J, Tyburski M B, Almon R, Berman M
North Shore University Hospital, Manhasset, New York 11030.
J Clin Microbiol. 1988 Nov;26(11):2382-6. doi: 10.1128/jcm.26.11.2382-2386.1988.
Of 337 urine specimens evaluated, 75 of the 113 that showed positive readings on the Bac-T-Screen urine-screening instrument were found by subsequent semiquantitative culture to yield either less than 10,000 CFU of mixed bacteria per ml or no growth (less than 100 CFU/ml by our criteria). We tried to determine what factors contributed to the positive Bac-T-Screen results by examining the 75 Bac-T-Screen-positive urine specimens with three visual methods: Gram staining, hemacytometer chamber counting, and filtering through a 5.0-microns-pore-size nitrocellulose filter with subsequent microscopic examination of the stained filter. Somatic cells and other particles present in those urine specimens that yielded positive readings by the Bac-T-Screen included epithelial cells in 43%, crystals and amorphous material in 33%, and leukocytes in 17% of the specimens. There was no relationship between the numbers of particles seen in urine and the magnitude of the relative absorbance reading obtained with the Bac-T-Screen. A retrospective chart review was conducted for patients with positive Bac-T-Screen results and negative cultures. Of the 75 patients, 6 were thought to have urinary tract infections on the basis of clinical criteria; the majority of the remaining 69 patients had clinical histories revealing systemic or urogenital conditions consistent with shedding of particles in the urine. A positive reading by the Bac-T-Screen system seemed to be related to the presence of somatic cells and other particles in urine; bacteriuria was not always detectable in these cases.
在评估的337份尿液标本中，113份在Bac-T-Screen尿液筛查仪器上显示阳性读数，其中75份经后续半定量培养发现每毫升混合细菌产生少于10,000 CFU或无生长（按照我们的标准少于100 CFU/ml）。我们试图通过三种视觉方法检查这75份Bac-T-Screen阳性尿液标本，以确定哪些因素导致了Bac-T-Screen结果呈阳性：革兰氏染色、血细胞计数器计数以及通过孔径为5.0微米的硝酸纤维素滤膜过滤，随后对染色后的滤膜进行显微镜检查。在那些Bac-T-Screen检测呈阳性的尿液标本中存在的体细胞和其他颗粒包括：43%的标本中有上皮细胞，33%有晶体和无定形物质，17%有白细胞。尿液中可见颗粒的数量与Bac-T-Screen获得的相对吸光度读数大小之间没有关系。对Bac-T-Screen结果为阳性但培养结果为阴性的患者进行了回顾性病历审查。在这75名患者中，根据临床标准，6名被认为患有尿路感染；其余69名患者中的大多数临床病史显示有与尿液中颗粒脱落相符的全身性或泌尿生殖系统疾病。Bac-T-Screen系统的阳性读数似乎与尿液中体细胞和其他颗粒的存在有关；在这些病例中并非总能检测到菌尿。
