Meeting NewsPerspective

New UTI test detects more bacteria than standard test

NEW ORLEANS — A new test performed on women discovered significantly more bacteria species than the standard test for urinary tract infection, according to findings presented at ASM Microbe.  

According to the American Urological Association, UTIs account for as many as 8.1 million visits to health care providers every year, and are the second-most common infection treated in the ED. The data also show that a woman’s lifetime risk for contracting at least one UTI ranges from approximately 40% to more than 50%.

Travis Price, MS, of Loyola University, and colleagues prospectively enrolled 150 urogynecologic patients and divided the group based on their answer to the question: ‘Do you feel you have a UTI?'

Researchers then conducted a standard urine culture of catheterized urine specimens. They also assessed bacterial growth using three versions of an enhanced quantitative urine culture protocol that utilized multiple media, an expansion of environmental culturing conditions, and 3 volumes of urine plated (1 µL, 10 µL and 100 µL). Price and colleagues also determined microbiota diversity using the average number of unique species per urine specimen.

Researchers found that the 100 µL enhanced quantitative urine culture protocol detected significantly more unique species (n = 95) than the standard urine culture (n = 11). Of all the uropathogens detected by the enhanced quantitative urine culture protocols, the standard urine culture missed 67% (122/182). In addition, in the ‘Yes’ cohort alone, standard urine culture missed 50% of the uropathogens. Standard culture detected 88% of the Escherichia coli (44/50), and discovered only 12% (16/132) of all other uropathogens. and streamlined enhanced quantitative urine culture detected more uropathogens (84%) than standard urine culture (33%).

“These findings support the necessity for an immediate change in urine culture procedures,” Price and colleagues wrote. “We recommend use of a streamline version of enhanced quantitative urine culture 100µL urine on Blood, CNA, and MacConkey agar incubated in 5% CO2 with 48 hours of incubation.”

According to a press release, another clinical trial will be conducted to investigate whether using the enhanced quantitative urine culture method could improve the clinical care of women with UTIs. The release also stated that 75 women with UTI symptoms will receive the standard culture plus enhanced quantitative urine culture and 150 women will receive the standard culture alone. – by Janel Miller

References:

NIH Webpage on UTIs in Women (accessed 06-02-17)

Price, T. et al. Detecting clinically relevant microorganisms: We can do better. Presented at: ASM Microbe; June 1-5, 2017; New Orleans.

Disclosure: Healio Family Medicine was unable to determine researchers’ relevant financial disclosures prior to publication.

NEW ORLEANS — A new test performed on women discovered significantly more bacteria species than the standard test for urinary tract infection, according to findings presented at ASM Microbe.  

According to the American Urological Association, UTIs account for as many as 8.1 million visits to health care providers every year, and are the second-most common infection treated in the ED. The data also show that a woman’s lifetime risk for contracting at least one UTI ranges from approximately 40% to more than 50%.

Travis Price, MS, of Loyola University, and colleagues prospectively enrolled 150 urogynecologic patients and divided the group based on their answer to the question: ‘Do you feel you have a UTI?'

Researchers then conducted a standard urine culture of catheterized urine specimens. They also assessed bacterial growth using three versions of an enhanced quantitative urine culture protocol that utilized multiple media, an expansion of environmental culturing conditions, and 3 volumes of urine plated (1 µL, 10 µL and 100 µL). Price and colleagues also determined microbiota diversity using the average number of unique species per urine specimen.

Researchers found that the 100 µL enhanced quantitative urine culture protocol detected significantly more unique species (n = 95) than the standard urine culture (n = 11). Of all the uropathogens detected by the enhanced quantitative urine culture protocols, the standard urine culture missed 67% (122/182). In addition, in the ‘Yes’ cohort alone, standard urine culture missed 50% of the uropathogens. Standard culture detected 88% of the Escherichia coli (44/50), and discovered only 12% (16/132) of all other uropathogens. and streamlined enhanced quantitative urine culture detected more uropathogens (84%) than standard urine culture (33%).

“These findings support the necessity for an immediate change in urine culture procedures,” Price and colleagues wrote. “We recommend use of a streamline version of enhanced quantitative urine culture 100µL urine on Blood, CNA, and MacConkey agar incubated in 5% CO2 with 48 hours of incubation.”

According to a press release, another clinical trial will be conducted to investigate whether using the enhanced quantitative urine culture method could improve the clinical care of women with UTIs. The release also stated that 75 women with UTI symptoms will receive the standard culture plus enhanced quantitative urine culture and 150 women will receive the standard culture alone. – by Janel Miller

References:

NIH Webpage on UTIs in Women (accessed 06-02-17)

Price, T. et al. Detecting clinically relevant microorganisms: We can do better. Presented at: ASM Microbe; June 1-5, 2017; New Orleans.

Disclosure: Healio Family Medicine was unable to determine researchers’ relevant financial disclosures prior to publication.

    Perspective
    Aaron Glatt

    Aaron E. Glatt

    The interesting paper by Price et al "Detecting clinically relevant microorganisms: We can do better" compares standard urine culture with an enhanced quantitative urine culture protocol using multiple media, an expansion of environmental culturing conditions, and 3 volumes of urine plated (1 µL, 10 µL and 100 µL) for the detection of clinically relevant microorganisms. This enhanced protocol detected more uropathogens, 84% (152/182), than did standard urine culture, 33% (60/182).

    While very interesting from a microbiological perspective, many clinical questions remain to be answered before adopting this new approach as a standard of clinical care. 

    First, for many clinical scenarios, the most cost effective approach is not to culture at all, as per the recommendation of the Infectious Diseases Society of America “International Clinical Practice Guidelines for the Treatment of Acute Uncomplicated Cystitis and Pyelonephritis in Women.” Empiric treatment without culture remains a very viable option in the appropriate patient population. 

    Second, when culture is indeed indicated, treatment is invariably started empirically prior to the culture results. This new enhanced protocol will only be effective when and if empiric therapy fails. Indeed, sensitivity results would also, of course, be critical in this scenario. 

    Third, the paper reported that “Women were treated clinically based on SC results.” Does this mean that the women were not treated until culture was available? If so, this represents a different population than the typical case of a woman presenting with urinary tract infection symptoms, who typically receives treatment at presentation. 

    Fourth and finally, the paper did not say what “cutoff” the standard urine culture used to discriminate between infection and not being infected. The literature clearly demonstrates that a cutoff that is too high or too low will misidentify patients along the spectrum of urethral syndrome / urinary tract infection / pyelonephritis, depending on the value being used.

    This paper, while clearly demonstrating that standard urine culture leaves much to be desired, does not yet provide sufficient information to declare that “These findings support the necessity for an immediate change in urine culture procedures.”

    Reference: Gupta K, et al. Clin Infect Dis. 2011; doi: 10.1093/cid/ciq257.

     

    • Aaron E. Glatt, MD, FACP, FIDSA, FSHEA
    • Chairman, Department of Medicine, South Nassau Communities Hospital, Oceanside, NY
      Spokesperson, Infectious Diseases Society of America

    Disclosures: Glatt reports no relevant financial disclosures.

    Perspective
    Costas D. Lallas

    Costas D. Lallas

    When considering a UTI in a patient presenting in an outpatient setting, a clinician must heavily rely on their judgment. The patient is often sent away initially on an empiric antibiotic that must be tapered depending on the results of the urine culture. This has significance in community-acquired UTI when considering atypical bacteria causing UTI, and the increase in bacteria that harbor antibiotic resistance. The [enhanced quantitative urine culture (EQUC)] protocol being promoted in the abstract claims that it is able to detect uropathogens at a much higher rate than on standard culture (SC). Although the numbers are impressive — SC was only able to detect approximately one-third pathogens that were detected by ECUQ, and less than half when compared to a ‘streamlined’ ECUQ — I do have some concerns regarding the practicality of the findings in the abstract. First, the 150 patients prospectively evaluated were split into two groups based on whether they believed they had a UTI. Most urologists argue that asymptomatic bacteriuria (represented by the ‘no’ group of the study) is not clinically relevant, and its detection and potential treatment is excessive and would lead to further antibiotic resistance. Next, although several more pathogens were detected via ECUQ, the clinical relevance of their presence is not determined. In other words, is individual treatment of every pathogen detected warranted, or would treatment of a dominant bacterium in a symptomatic patient be sufficient to successfully alleviate their symptoms? Finally, there are some unanswered questions regarding the practicality of the ECUQ and streamlined ECUQ protocols when compared to SC, namely their relative ease of implementation and cost, two factors that should be investigated. In conclusion, when it comes to detection of uropathogens, more may not be better, and new protocols should be evaluated comprehensively prior to replacing the standard of care.

    • Costas D. Lallas, MD, FACS
    • Professor of Urology, Vice Chair of Academic Affairs, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia

    Disclosures: Lallas reports no relevant financial disclosures.

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