Culture of Urine Specimens by Use of chromID CPS Elite Medium Can Expedite Escherichia coli Identification and Reduce Hands-On Time in the Clinical Laboratory

Abstract

Urine is one of the most common specimen types submitted to the clinical microbiology laboratory; the use of chromogenic agar is one method by which the laboratory might expedite culture results and reduce hands-on time and materials required for urine culture analysis. The objective of our study was to compare chromID CPS Elite (bioMérieux), a chromogenic medium, to conventional primary culture medium for evaluation of urine specimens. Remnant urine specimens (n ‫؍‬ 200) were inoculated into conventional media and into chromID CPS Elite agar (chromID). The time to identification and consumables used were documented for both methods. Clinically significant pathogen(s) were recovered from 51 cultures using conventional media, with Escherichia coli being the most frequently recovered organism (n ‫؍‬ 22). The rate of exact uropathogen agreement between conventional and chromogenic media was 82%, while overall categorical agreement was 83.5% The time interval between plating and final organism identification was decreased with chromID agar versus conventional media for E. coli (mean of 24.4 h versus 27.1 h, P < 0.001). Using chromID, clinically significant cultures required less hands-on time per culture (mean of 1 min and 2 s [1:02 min]) compared to conventional media (mean of 1:31 min). In addition, fewer consumables (2.4 versus 3.3 sticks and swabs) and rapid biochemical tests (1.0 versus 1.9) were necessary using chromID versus conventional media. Notably, antimicrobial susceptibility testing demonstrated good overall agreement (97.4%) between the chromID and conventional media for all antibiotics tested. chromID CPS Elite is accurate for uropathogen identification, reduces consumable usage, and may expedite the identification of E. coli in clinical specimens. U rinary tract infections (UTIs) are among the most common bacterial infections worldwide (1). Screening urine cultures to identify significant uropathogens can require considerable hands-on time, consumable usage, and biochemical testing. As a result, urine cultures to support a diagnosis of UTI account for a major share of the workload in microbiology laboratories (2), which are facing a shortage of skilled laboratory personnel (3). Thus, there is a need for accurate methods that save time and reduce workload. In addition, there is growing emphasis on expediting culture results from patients with infection; minimizing the window of diagnostic uncertainty is essential to optimize antimicrobial therapy and improve patient outcomes (4).One approach to streamline urine culture is the rapid identification of organisms from growth on solid agar using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). This method has been shown to be accurate and cost-effective for identification of bacterial and fungal organisms (5-15). However, considerable hands-on time may be necessary upstream of MALDI-TOF MS to isolate significant uropathogens from standard media, particularly for patients with mixed infections.The majority of com...

Evaluation of WASPLab Software To Automatically Read chromID CPS Elite Agar for Reporting of Urine Cultures

“…Other studies have looked at the effects on TAT for CPSE agar using only manual reading and reporting. One study evaluated 200 urine specimens using the CPSE agar and found that the time to ID for E. coli was significantly reduced (2.7-h reduction) in a comparison of bacterial culture on blood agar and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for identification (21). The study also evaluated hands-on time and consumable usage and found that CPSE agar required 30 s less hands on time (on average) and used 1 less swab and biochemical test per specimen.…”

The Usefulness of Chromogenic Media for Qualitative and Semi-Quantitative Diagnostic of Urinary Tract Infections

“…Enteroccocal growth was inhibited in three of the five tested media (UTI C, BMagar and Microbiology laboratories always attempt to reduce the turnaround time and the cost of pathogens identification and their susceptibility testing (Strauss and Bourbeau, 2015). In recent years, chromogenic culture media have been widely used in clinical microbial diagnostic for detection and preliminary identification of pathogens and antimicrobial resistance mechanisms (Fillius et al, 2003;Kuch et al, 2009;Stefaniuk et al, 2016a;Yarbrough et al, 2016). In our study, apart from the results obtained using the three chromogenic media used all over the world (CPSE, ORI and UTI C), we present results obtained using two media manufactured in Poland: BMagar -BioMaxima and ORIE -Graso, which are offered for a lower price.…”

“…The pathogen identification is based on chromogenic substrates contained in the media to detect the bacterial enzymes, mainly β-galactosidase, β-glucosidase, β-glucuronidase (the bacteria grow in the form of pink-red or blue-green colo nies, respectively) and tryptophan deaminase, which is characteristic for the Proteae group of bacteria (Proteus-Morganella-Providencia). These pathogens appear on chromogenic media as brownish colonies (Fallon et al, 2003;Pezzlo, 2014;Yarbrough et al, 2016).…”

Evaluation of chromogenic agar medium. Can it be a suitable alternative to conventional culture system for identification of uropathogens?

“…It also failed to identify two isolates of Enterobacter spp. Their final identification required additional biochemical reactions ( 31 ). Inability to identify Citrobacter, Burkholderia, Acinetobacter, Group B Streptococcus and Enterobacter were not included as major errors as this media does not reliably detect them.…”