DIAGN MICROBIOLINFECTDIS 1990;13:289-295
Evaluation of the FiltraCheck-UTI for Detection of Bacteriuria Charles E. Stager and James R. Davis
The FiltraCheck-UTI (FC) is a disposable colorimetric urine screen for bacteriuria that requires -105 CFU/ml was 94.8%, 97.4%, and 77.9% respectively. These values for specimens with probable pathogens at ~104 CFU/ml were 91 .I %, 92.1%, and 74.3%, respectively. When the LN was combined with the FC or BTS as a urine screen, the sensitivity for probable pathogens was improved.
units (CFU)/ml of a potential pathogen. The evolving criteria for interpretation of urinary tract infection most likely will not only incorporate the numbers and types of microbes but the number of PMNs and the patient's symptoms. This work was not performed to answer the question of what constitutes a significant culture or urinalysis result but to compare the result of a disposable urine screen for bacteriuria, the FiltraCheck-UTI (FC; Applied Polytechnology, Houston, TX), with those obtained with the Bac-T-Screen (BTS; Vitek Systems, Hazelwood, MO), a semiautomated urinescreening device, the Chemstrip LN test strip (LN; Boehringer and Mannheim Diagnostics, Indianapolis, IN), and a quantitative culture procedure. The potential for a combined urine screen, by using the LN with either the FC or the BTS tests, was also evaluated.
There have been many changes in urine microbiology in the past several years. These changes have occurred both in the procedures available to determine the presence of microbes and the interpretive criteria. The procedural changes are centered around methods to screen urine specimens for the presence of either "significant" numbers of microorganisms (Jorgensen and Jones, 1975; Pezzlo, 1987) polymorphonuclear (PMN) leukocytes (Perry et al., 1982; Smalley and Dittmann, 1983; Bartlett et al., 1984; Pfaller and Koontz, 1985; Cannon et al., 1986; Jones et al., 1986; Marsik et al., 1986; Gutman and Solomon, 1987;), or both (Wallis et al., 1981; Hoyt and Ellner, 1983; Pezzlo et al., 1983 and 1985; Pfaller et al., 1983 and 1987; Cashman et al., 1984, Davis and Stager, 1985; Longoria and Gonzalez, 1987; Murray et al., 1987 and 1988). The interpretative criteria are being redefined (Stamey and Pfau, 1970; Stamm et al., 1980 and 1982; Stark and Maki, 1984; Latham et al., 1985; Strand et al., 1985; Lipsky et al., 1987; York and Brooks, 1987) and will never again be as simple as that applied in the past, i.e., ~105 colony forming From the Department of Pathology, BaylorCollege of Medicine (C.E.S., J.R.D.), and the Methodist Hospital (J.R.D.), Houston, Texas. Address reprint requests to:James R. Davis, Ph.D., Department of Pathology, The Methodist Hospital, 6565 Fannin, Houston, TX 77030. Received December 11, 1989; revised and accepted February 27, 1990. © 1990Elsevier Science Publishing Co., Inc. 655 Avenue of the Americas, New York, NY 10010 0732-8893/90/$3.50
MATERIALS A N D METHODS Specimens Urine specimens (551) were collected from inpatients and outpatients at the Methodist Hospital, Houston, TX. The protocol required the specimens to be processed within 2 hr after collection, or they were refrigerated and processed within 6 hr.
Cultures Method Urine specimens were inoculated onto both MacConkey/colistin-nalidixic acid blood agar biplates and
C.E. Stager and J.R. Davis
5% sheep blood agar plates (Scott Laboratories, Fiskeville, RI) by a flood plate procedure (Long, 1974). The plates were incubated aerobically at 35°C and examined at 24 and 48 hr. Colony-forming units per milliliter were determined by comparing the growth with photographs of media inoculated with known concentrations of bacteria. The Automicrobic System Gram Negative Identification Card (Vitek Systems) or conventional procedures (Lennette et al., 1980) were used to identify the isolates.
Interpretative Criteria The semiquantitative culture results were separated into three categories: ->105, ---104 and