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Advanced UTI Testing: Impact of Quick Turn Around Time to Result on Clinical Decisions

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 5 Oct 2023 || By Clinical Conversations Staff Shares: Versions of this article Original article. Tags PCR, UTI

Impact of complicated urinary tract infections

Urinary tract infections (UTIs) are among the most common infections, and they are usually a frequent source of primary infection in patients who present with sepsis or septic shock.1 They are also a serious clinical condition that accounts for over 10 million office visits and about 3 million Emergency Department (ED) visits in the United States costing $3.5B annually.2

Complicated UTIs (cUTIs) occur in individuals who have one or more risk factor(s) predisposing a patient to a higher likelihood of treatment failure and/or poor outcomes.3,4 Due to the elevated risk of recurrence and complications in these patients, they may benefit from the reduced time to results of advanced UTI tests.

Traditional method of UTI diagnosis and its limitations

Standard Urine Culture (SUC) has been the gold standard for UTI diagnosis and it has played a major diagnostic role in the management of patients with suspected UTIs.4 Despite SUC being the gold standard for UTI diagnosis, it has several shortcomings.  Those shortcomings include a prolonged turnaround time (TAT) for culture, which may take a minimum of two days or up to five days to receive a result with corresponding sensitivity profiles.5 Delayed time to result may also increase use of empiric antimicrobial therapy3 or a delay in the initiation of effective and appropriate therapy.

Culture is also susceptible to problems of contamination with an average reported rate of about 15%5 of cases not able to provide sensitivities for this reason. These problems are attributed to urine culture difficulties in obtaining results with low bacterial growth and in cases of polymicrobial infections4. These limitations also include the inability to detect other relevant organisms, such as fastidious organisms that may cause UTI.4 SUC often fails to identify more than two organisms in polymicrobial infections, resulting in ‘mixed flora’ or ‘contamination’ findings.

Emergence of molecular diagnostics for UTI

Polymerase chain reaction (PCR) is a rapid diagnostic method of “molecular photocopying,” which is used in the amplification of DNA segments.7 This method is utilized in the detection of infectious pathogens as well as the diagnosis of non-infectious medical conditions6 and this has resulted in PCR becoming a valuable method of organism identification in the area of infectious diseases.5

PCR has been found to have better sensitivity and specificity when compared to SUC in the detection and identification of pathogens.2 It generally has a faster turnaround time than culture with results available in as little as one day while SUC could take two days or more and fastidious pathogens could even take longer.

Effect of monomicrobial and polymicrobial UTIs on diagnosis and antimicrobial selection

Standard culture may also have limitations when the infection is polymicrobial as results may be considered as a contamination. Newer methods such as Pooled Antibiotic Susceptibility Testing (P-AST™), which is a part of Guidance® UTI, involves simultaneously growing all detected bacteria together in the presence of antibiotics to identify antibiotic susceptibility that accounts for these interactions and is able to be delivered with similar fast turnaround time of one day from receipt of specimen.

Conclusions

Advanced UTI testing that includes a combination of PCR for organism identification and novel pooled antibiotic susceptibility testing (P-AST™) could shorten the time to the detection of pathogens and provide information on antibiotic susceptibility, when compared to standard urine culture and sensitivities.  This is additional information that may potentially lead to faster initiation of appropriate and targeted therapy and thereby decrease the time of exposure to ineffective empiric therapy. Together, these technologies may support antibiotic stewardship. Good antibiotic stewardship and reduction in conditions that may lead to anti-microbial resistance (AMR) could have an impact on the rate of morbidity and mortality, patient admission rates, and a reduction in cost of UTI management.

Request Infographic: Urinary Tract Infections

About the Author

Temitayo Famoroti is a trained Medical Doctor (MD)/ Pathologist (Clinical Virologist) with experience in patient management, clinical research, laboratory medicine, and Medical Affairs. His work experience also includes management of Infectious Diseases, Vaccinology/ immunology, Rapid diagnostics/ Point of care Tests (POCT) and he has taught both undergraduate and postgraduate students at the university level. As a clinician, he is passionate about quality assurance in the laboratory, keeping up to date with the changes in the world of molecular diagnosis, emerging and re-emerging pathogens, drug and vaccine development including participating in public health programs. As a Medical Science Liaison (MSL) at Pathnostics, he maintains an in-depth knowledge for Guidance® product(s), engaging and responding to Health Care Practitioners (HCP) inquiries.

References

  1. Carreno, J.J., Tam, I.M., Meyers, J.L., Esterberg, E., Candrilli, S.D. and Lodise Jr, T.P., 2019, November. Longitudinal, nationwide, cohort study to assess incidence, outcomes, and costs associated with complicated urinary tract infection. In Open Forum Infectious Diseases (Vol. 6, No. 11, p. ofz446). US: Oxford University Press.
  2. Zilberberg MD, Nathanson BH, Sulham K, Shorr AF. Descriptive epidemiology and outcomes of emergency department visits with complicated urinary tract infections in the United States, 2016-2018. J Am Coll Emerg Physicians Open. 2022 Mar 17;3(2):e12694. doi: 10.1002/emp2.12694. PMID: 35342898; PMCID: PMC8931190.
  3. Sabih, Ayan, and Stephen W. Leslie. “Complicated urinary tract infections.” StatPearls [internet]. StatPearls Publishing, 2022.
  4. N. Luke, D. Baunoch. After 180 Years, Is it Time for Something Better for Diagnosing UTI’s?. JOJ Urology & Nephrology, 2020; 7(2): 555714
  5. National institute of health: National human genome research institute. Polymerase Chain Reaction (PCR) Fact Sheet. https://www.genome.gov/about-genomics/fact-sheets/Polymerase-Chain-Reaction-Fact-Sheet (Assessed 26th Jan 2023)
  6. Xu R, Deebel N, Casals R, Dutta R, Mirzazadeh M. A New Gold Rush: A Review of Current and Developing Diagnostic Tools for Urinary Tract Infections. Diagnostics (Basel). 2021 Mar 9;11(3):479. doi: 10.3390/diagnostics11030479. PMID: 33803202; PMCID: PMC7998255.
  7. Nityadarshini, N., Mohapatra, S., Gautam, H., Jain, V., Chaudhry, R. and Kapil, A., 2022. Polymicrobial growth in standard urine culture: Time to Act or Ignore?. Tropical Doctor, 52(2), pp.335-336.