As with everyone’s favorite series about small magical animal fighting rings, our clinical guidelines occasionally evolve into newer and ostensibly better forms. This usually happens to a guideline every decade or so; this month we got the newest iteration of guidelines for the management of asymptomatic bacteriuria (ASB), the last iteration having been published in 2005. So I wondered: in 14 years, how much have the IDSA’s recommendations actually changed? Below, I reviewed the summary recommendations of both sets of guidelines, and compare and contrast the two:
The 2005 and 2019 guidelines agree that healthy nonpregnant women, diabetic women, elderly patients (be they institutionalized or living in the community), patients with spinal cord injury, and patients with short or long-term indwelling urinary catheters should not be routinely screened or treated for ASB. However, the 2019 guidelines significantly expand these recommendations. Populations in whom the 2019 guidelines recommend against ASB screening and treatment include children, diabetic men, elderly patients who are functionally impaired, patients who have had kindney transplants after the first month post-transplant, patients who have received any other type of solid organ transplant, patients undergoing any non-urologic surgery, and patients undergoing urologic device implantation or living with urologic devices (e.g. penile prostheses). The 2019 guidelines leave open the question of whether ASB screening or treatment should be done in the first month after kidney transplant or in neutropenic patients, and they recommend treatment in a few select cases (e.g. in patients undergoing endourologic procedures and in pregnancy).
A few changes here are worth remarking upon. First, most of these recommendations (both new and old) are “strong, low-quality evidence.” Such is the state of infectious diseases research. Second, while the 2019 guidelines concur with the 2005 guidelines about the need to screen and treat ASB in pregnancy, they do hedge their bets a bit, noting that new data suggests ASB nontreatment may be safe for some low-risk women. However, the committee did not change their recommendation base on this data, feeling it was too preliminary to be safe generalized. On the other hand, they do point out the lack of evidence for repeat ASB screening (or test-of-cure urine cultures) in pregnancy, and do not recommend either approach.
Third, the expansion of “don’t test or treat ASB in diabetes” to cover women is not based on any specific data in men, but inferred from clinical trials that primary enrolled women. This recommendation reflects what I hope is the start of a sea change in how we regard male UTI – that is, perhaps reflecting some underlying comorbidity that has overcome the male urethra’s propensity for excluding uropathogens, but not necessarily a more severe or difficult-to-treat infection than UTI in women. (I have this notion that male UTI got a bad rap as needing long courses of antibiotics because doctors are bad at diagnosing prostatitis, and also because it mostly occurs in the setting of other complicated factors like spinal cord injury or long-term catheterization – but that’s a topic for another time). Fourth, while the 2019 guidelines refrain from making any recommendations about ASB screening and treatment in neutropenia, they do delineate between “high-risk neutropenia” (ANC <100 and >7 days in duration after chemotherapy) and “low-risk neutropenia,” and point out that the uncertainty is mostly in the former, and that there is no evidence to suggest that ASB is clinically meaningful in the latter. So, perhaps we can look forward to the 2030 ASB guidelines giving us the blessing to ignore ASB in neutropenic patients so long as it’s not “high-risk.”
Finally, the 2019 guidelines specifically recommend workup of non-UTI causes for nonspecific symptoms in the functionally and cognitively impaired older adult (a sticking point for internists and geriatricians everywhere). That is to say, if a patient has bacteriuria and delirium without local urinary symptoms or systemic evidence of infection (e.g. fever, hypotension), the guidelines recommend against empiric antimicrobial treatment, instead suggesting… well, an actual clinical evaluation. They extend this recommendation to older patients who begin to experience falls. In their explanation, the committee points toward lack of established benefit for early antibiotics in this situation, versus the clear benefit of avoiding C.difficiile infection, antimicrobial resistance, and adverse drug evens in a medically vulnerable population. This is the same reasoning the committee uses to justify not screening or treating for ASB in nonrenal transplant patients – in whom, they point out, UTI is uncommon and rarely a big deal.
And with that, let’s talk about this month’s ID literature:
Antimicrobial agents research covered the genetics, identification, and treatment of organisms with AmpC beta-lactamases, a trial of ceftriaxone vs flucloxacillin for pediatric cellulitis, why gangciclovir therapeutic drug monitoring probablby isn’t coming to a hospital near you, and a new trial of an oral beta-lactamase to prevent CDI in patients given beta-lactams.
ID diagnostics papers this month discussed valve PCR for the diagnosis of endocarditis, the diagnostic value of BAL Aspergillus PCR testing for invasive aspergillosis, and the yield of BAL studies for tuberculosis in patients with negative sputum studies.
General ID topics covered include amoxicillin MICs as a predictor of outcome in streptococcal endocarditis, the primacy of surgery in MDR and XDR gram-negative prosthetic joint infections, the utility of short-course rifapentine and isoniazid for preventing TB disease in patients with HIV, and the efficacy of “shorter course” therapy with high-dose moxifloxacin in patients with rifampin-resistant tuberculosis.
HIV and STDs research this month included an update on the incidence and prevalence of HIV among various groups in the US, risk factors and outcomes of CSF viral escape in patients with HIV and controlled serum viral loads, the efficacy of alternate day vs daily efavirenz-tenofovir-emtricitabine, and patients’ enduring optimism about whether they need PrEP.
Onc and transplant ID research covered the prevalence of invasive aspergillosis in patients with newly diagnosed AML, the safety of MMR vaccination in liver transplant recipients, and the epidemiology and lousy outcomes of cryptococcosis in immunocompromised patients without HIV.
Antimicrobial stewardship and infectious control literature from this month included papers on the overuse of antimicrobials at the end of life, the AMR consequences of second-hand fluroquinolone exposure, the superiority of two-dose vaccination for varicella in children, and the proportion of hospital-onset C.difficile infection attributable to pre-admission colonizing C.difficile strains.