Aaron E. Glatt, MD, FACP, FIDSA, FSHEA

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.

Costas D. Lallas, MD, FACS

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.