Evaluation of New bioMérieux Chromogenic CPS Media for Detection of Urinary Tract Pathogens

Novel Techniques to Unravel Causative Bacterial Ecological Shifts in Chronic Urinary Tract Infection

Chronic urinary tract infection (UTI) presents with protracted lower urinary tract symptoms and elevated urinary leukocyte counts, but its bacterial etiological agents remain obscure. In this cross-sectional investigation, we aimed to unravel the role of the bladder microbiota in chronic UTI pathogenesis by studying the host immune response. Urine samples were collected from healthy controls (HT), chronic UTI patients who had not initiated treatment (PT) and those undergoing treatment (OT), then sorted into white blood cell (WBC) and epithelial cell (EPC) fractions. Bacteria associated with both fractions were identified by chromogenic agar culture coupled with mass spectrometry and 16S rRNA sequencing. Distinct WBC-exclusive bacteria were observed in the healthy population, but this pattern was less obvious in patients, plausibly due to epithelial shedding and breaching of the urothelial barrier. We also described a bacterial fingerprint guided by Escherichia that was able to stratify patients based on symptom severity. Clustering analyses of mean rank changes revealed highly statistically significant upward and downward ecological shifts in communities of bacteria between the healthy and diseased populations. Interestingly, many of the most abundant genera identified in sequencing remained stable when compared between the study cohorts. We concluded that reshuffling of the urinary microbiome, rather than the activity of a single known urinary pathogen, could drive chronic UTI.

Antimicrobial susceptibility patterns of community-acquired uropathogenic Escherichia coli, Dublin 2010-2022

Background

Escherichia coli is a common cause of urinary tract infections. Due to the increase in antimicrobial resistance (AMR) and global differences in antimicrobial susceptibility data, routine assessment of local antimicrobial susceptibility patterns is necessary to guide the selection of appropriate empirical therapy. The aim of this study was to evaluate the antimicrobial susceptibility patterns of community-acquired uropathogenic Escherichia coli within a catchment area in Dublin over a 13 year period, 2010-2022.

Methods

All mid-stream urine samples received from local general practitioners in which there was significant E. coli bacteriuria during the study period, 2010-2022, were included in the analysis. Antimicrobial susceptibility testing was performed by disc diffusion as per the European Committee on Antimicrobial Susceptibility Testing recommendations.

Results

An average of 11 407 urine samples per month had significant bacteriuria, with E. coli accounting for an average of 67 % of those. Overall AMR rates were highest for ampicillin (53.9 %), followed by trimethoprim (32.4 %), gentamicin (18.6 %), co-amoxiclav (16.5 %), ciprofloxacin (12.3 %), cephalexin (8.3 %), cefpodoxime (6.8 %) and nitrofurantoin (2 %). While rates appeared grossly static, statistically significant reduced resistance rates were noted for co-amoxiclav (rs=-0.95; P=<0.001), cephalexin prior to 2019 (rs=-0.783; P=0.013) and trimethoprim (rs=-0.639; P=0.019), with a statistically significant increase in non-susceptibility to cefpodoxime (rs=0.802; P=0.001).

Conclusions

In order to generate efficient empirical antimicrobial prescribing guidelines, knowledge of region-specific contemporaneous antimicrobial susceptibility patterns is pivotal. Our findings support the use of nitrofurantoin or cephalexin as empirical antimicrobial therapy within our setting.

On-site verification of the CBEU method using UriSelect4 chromogenic medium at the National Institute of Hygiene (INH) of Lomé

PURPOSE

The Cytobacteriological Examination of Urine (CBEU) is one of the most requested microbiological analyses in the medical bacteriology laboratory. According to the ISO 15189 standard, Medical Biology Laboratory (MBL) must validate the techniques before their use. It is in this perspective that, within the Medical Bacteriology Laboratory of the INH of Lome, we have carried out the on-site verification of the CBEU method using UriSelect4 chromogenic medium at the INH of Lomé.

MATERIAL AND METHODS

The biological material was composed of reference bacterial strains and clinical bacterial strains isolated at INH. Failure Modes Effects and Criticality Analysis (FMECA) with 5 ​M model was used to perform risk analysis and performances as repeatability, intermediate fidelity/reproducibility, sensitivity and inter-operator variability were evaluated using references strains and different operators. "Comité Français d'Accréditation" (COFRAC) SH GTA 04 was used as reference. Single-factor ANOVA was used to analyze the data.

RESULTS

Operating procedures, Patients preparation, Samples and Preparation of culture media were identified as main critical points with a criticality index of 8, 9, 9 and 12 respectively. The use of uriselect4 to perform ECBU was shown to be repeatable and reproducible. The sensibility of Uriselect4 to detect urinary infection was 100% with negligible inter-operator variability.

CONCLUSION

This study performed on-site verification of Uriselect4 at the bacteriology lab of INH of Lome and identified some critical points to master. The overall performance criteria from COFRAC SH GTA 04 were conform.

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.

Use of artificial intelligence for tailored routine urine analyses

OBJECTIVES

Urine is the most common material tested in clinical microbiology laboratories. Automated analysis is already performed, permitting quicker results and decreasing the laboratory technologist's (LT) workload. These automatic systems have introduced digital imaging concepts. PhenoMATRIX (PHM) is an artificial intelligence software that merges picture algorithms and user rules to provide presumptive results. This study aimed at designing a tailored workflow using PHM, performing its validation and checking its performance in routine practice.

METHODS

Two data collections including 96 and 135 urine samples from nephrostomy/ureterostomy and artificial bladder (US), 948 and 1257 urine samples from catheter (UC) and 3251 and 2027 midstream urine (MSU) were used to compare LT results with those obtained using two versions of PHM. Another 19 US, 102 UC and 508 MSU were used to monitor performance level 3 months after routine implementation.

RESULTS

Before and after revisions, agreement between the first version of PHM and LT results were 83% (95% confidence interval [CI], 74.3-90.2) and 83% (95% CI, 75.3-90.9) (US), 66.7% (95% CI, 63.5-69.5) and 71.7% (95% CI, 68.8-74.4) (UC) and 65.4% (95% CI, 63.8-67.1) and 76% (95% CI, 74.1-77.1) (MSU). The second version improved results, demonstrating 96.2% (95% CI, 91.6-98.8) and 97% (95% CI, 92.6-99.2) (US), 87.5% (95% CI, 85.5-89.2) and 88.9% (95% CI, 87.0-90.5) (UC) and 91% (95% CI, 89.7-92.1) and 92% (95% CI, 91.1-93.4) (MSU) of agreement with LT results before and after revisions. The reliability of PHM results was confirmed by a routine study demonstrating 92% (95% CI, 90.0-94.2) overall agreement.

CONCLUSIONS

PHM showed high performance, with >90% of results in agreement with LT. PHM could help standardize and secure results, prioritize positive plates during analytical workflow and likely save LT time.

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.

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

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.