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

First Case of Raoultella planticola Urinary Tract Infection Reported in Western Romania

Raoultella planticola is a Gram-negative bacterium rarely involved in urinary tract infections. The patient was an 80-year-old woman with several associated diseases who presented to the hospital with fever and dysuria. Raoultella planticola was identified to be the causative agent of the urinary tract infection. Antibacterial treatment led to a full recovery within 7 days. This report highlights the presence of a rare pathogen as a causative agent in the case of a urinary tract infection and also the importance of using multiple methods in order to identify bacteria and to establish the diagnosis.

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

Background and Objectives

Urinary tract infections (UTI) account for major proportion of outpatient load and hospital admission globally. In most of the clinical microbiology laboratories MacConkey agar (MAC) and Cystine lactose electrolyte-deficient (CLED) agar are being used for identification of uropathogens. The main objective of the present study was to evaluate the usefulness of HiCrome^TM UTI by comparing isolation rate and presumptive identification of uropathogens against CLED and MAC agar.

Materials and Methods

This study was conducted over a period of three months on 672 non-duplicate midstream and/or catheter-catch urine samples. All samples were inoculated on to HiCrome^TM UTI, CLED agar and MacConkey agar.

Results

Among the 672 samples received for culture, 113 (16.8%) showed significant growth. Among the 672 samples, 95 (14.1%) showed growth of a single organism while 18 (2.7%) showed polymicrobial growth. The rate of isolation and presumptive identification of the isolates and polymicrobial growth was found significantly higher on HiCrome^TM UTI Agar.

Conclusion

HiCrome^TM UTI Agar has the potential to streamline processing of samples for urine culture in a way that will reduce the workload for technicians, reduce turnaround time which in turn will benefit the laboratory ultimately leading to better patient care.

Toilet-based continuous health monitoring using urine

Regular health monitoring can result in early detection of disease, accelerate the delivery of medical care and, therefore, considerably improve patient outcomes for countless medical conditions that affect public health. A substantial unmet need remains for technologies that can transform the status quo of reactive health care to preventive, evidence-based, person-centred care. With this goal in mind, platforms that can be easily integrated into people's daily lives and identify a range of biomarkers for health and disease are desirable. However, urine - a biological fluid that is produced in large volumes every day and can be obtained with zero pain, without affecting the daily routine of individuals, and has the most biologically rich content - is discarded into sewers on a regular basis without being processed or monitored. Toilet-based health-monitoring tools in the form of smart toilets could offer preventive home-based continuous health monitoring for early diagnosis of diseases while being connected to data servers (using the Internet of Things) to enable collection of the health status of users. In addition, machine learning methods can assist clinicians to classify, quantify and interpret collected data more rapidly and accurately than they were able to previously. Meanwhile, challenges associated with user acceptance, privacy and test frequency optimization should be considered to facilitate the acceptance of smart toilets in society.

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

Urine cultures are among the most common specimens received by clinical laboratories and generate a major share of the laboratory workload. Chromogenic agar can expedite culture results, but technologist review is still needed. In this study, we evaluated the ability of the WASPLab software to interpret urine specimens plated onto chromID CPS Elite (CPSE) agar. Urine specimens submitted for bacterial culture were plated onto CPSE agar with a 1-μl loop using the WASP. Each plate was imaged after 0 and 18 h of incubation, and colonies were enumerated by color using the WASPLab software and a technologist's reading from a high-definition (HD) monitor. The results were reported as negative if <10 colonies/plate were detected. Laboratory information system (LIS) time stamps were used to measure the time to result. A total of 1,581 urine cultures were tested. The sensitivity and specificity of the software were 99.8% and 68.5%, respectively, which included 2 manual-positive/automation-negative (MP/AN) results and 170 manual-negative/automation-positive (MN/AP) results. Of the 170 MN/AP specimens, 116 were caused by microcolonies missed by the technologist. The remaining MN/AP results were caused by either count differences near the 10-colony threshold (n = 43) or count differences of >50 CFU (n = 11). The use of both CPSE agar and the WASPLab software improved the time to result for urine culture, reducing the average time to result by 4 h 42 min for negative specimens and 3 h 28 min for positive specimens compared to that with standard-of-care testing. These data demonstrate that the use of CPSE agar and automated plate reading has the potential to improve turnaround time while maintaining high sensitivity and reducing urine culture workload.

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

The aim of this study was to evaluate the usefulness of chromogenic media for isolation of bacteria from urine and direct identification of UTI pathogens. A total of 100 urine specimens were inoculated on blood agar and MacConkey agar as a reference method and on the following media to be tested: chromID^® CPS^® Elite (CPSE, bioMérieux), CHROMagar™ Orientation (BioMaxima), BD CHROMagar Orientation Medium (ORI, Becton Dickinson), CHROMagar™ Orientation (ORIE, Graso) and Brillance UTI Clarity Agar (UTI C, Oxoid). After a 24-hour incubation period, 47 Gram-positive cocci and 62 Gram-negative rods were observed. The specificity and sensitivity of all chromogenic media was 97.3% and 93.5% respectively for qualitative diagnostic; and 81.9% and 81.3% respectively for semi-quantitative diagnostic. The mean PPV and NPV of the chromogenic media were 98.7% and 87.7% for qualitative UTI diagnostic, and 90.9% and 71.9% respectively for semi-quantitative diagnostic.

A Decade of Development of Chromogenic Culture Media for Clinical Microbiology in an Era of Molecular Diagnostics

In the last 25 years, chromogenic culture media have found widespread application in diagnostic clinical microbiology. In the last decade, the range of media available to clinical laboratories has expanded greatly, allowing specific detection of additional pathogens, including Pseudomonas aeruginosa, group B streptococci, Clostridium difficile, Campylobacter spp., and Yersinia enterocolitica. New media have also been developed to screen for pathogens with acquired antimicrobial resistance, including vancomycin-resistant enterococci, carbapenem-resistant Acinetobacter spp., and Enterobacteriaceae with extended-spectrum β-lactamases and carbapenemases. This review seeks to explore the utility of chromogenic media in clinical microbiology, with particular attention given to media that have been commercialized in the last decade. The impact of laboratory automation and complementary technologies such as matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is also assessed. Finally, the review also seeks to demarcate the role of chromogenic media in an era of molecular diagnostics.

Fast methods of fungal and bacterial identification. MALDI-TOF mass spectrometry, chromogenic media

MALDI-TOF mass spectrometry is now a routine resource in Clinical Microbiology, because of its speed and reliability in the identification of microorganisms. Its performance in the identification of bacteria and yeasts is perfectly contrasted. The identification of mycobacteria and moulds is more complex, due to the heterogeneity of spectra within each species. The methodology is somewhat more complex, and expanding the size of species libraries, and the number of spectra of each species, will be crucial to achieve greater efficiency. Direct identification from blood cultures has been implemented, since its contribution to the management of severe patients is evident, but its application to other samples is more complex. Chromogenic media have also contributed to the rapid diagnosis in both bacteria and yeast, since they accelerate the diagnosis, facilitate the detection of mixed cultures and allow rapid diagnosis of resistant species.