477. Characterization of Extended-Spectrum Β-Lactamase (ESBL) Producing Gram-negative (GN) Urinary Tract Infections (UTI) in Pediatric Patients

Background There has been an increase in antimicrobial resistance among GN pathogens, not only in adults, but also pediatrics. UTIs are common in pediatrics; however, reports of pediatric UTI with ESBL producing GN are limited. Methods All urine cultures positive for ESBL producing GN from 5/1/18 to December 31/18 were retrospectively reviewed. Proven infection (PI) defined as ≥50,000 colony-forming units (CFU)/mL of bacteria plus pyuria or positive leukocyte esterase for catheterized or clean catch specimens. Relapsed infection defined as same pathogen cultured within 30 days of infection. Abnormal urinary tract systems or functions (AUTS) include neurogenic bladder, structural anomalies, or intermittent catheterization. Results A total of 107 urine cultures for ESBL producing GN, from 85 patients, were included. Majority of specimens [78/107 (73%)] were obtained from the ED or outpatient clinics. 43% of specimens were from patients with AUTS. E. coli was the majority (95%) of ESBL isolates. 57% of ESBL producing GNs were susceptible to amoxicillin/clavulanate (AC) or trimethoprim/sulfamethoxazole (TMP/SMX). 88% were nitrofurantoin susceptible. Only 1 isolate was meropenem resistant. Antibiotics (ABX) were prescribed for UTI in 67/107 episodes. However, only 52 episodes were PI. Of these, 38 were empirically treated with oral ABX and 29 with intravenous ABX. The most commonly prescribed empiric ABX was oral cephalexin (25/67, 37%.) Ineffective empiric ABX for UTI was very common, 83% (43/52). Of these, 5/43 never received effective therapy and none had relapse. Most common duration of ABX was 10 days (range 5–17 days.) 43% (23/52) of PI were treated with oral AC or TMP/SMX. 15% (8/52) of PI were treated with nitrofurantoin. 12% of PI were treated with a once-daily aminoglycoside. Only 6% of PI were treated with a carbapenem. Conclusion Many ESBL UTI isolates remain susceptible to oral ABX. Although small numbers, patients treated with ineffective ABX did not return with relapsed infection. Non-carbapenem ABX are a reasonable option to minimize selective pressure or unnecessary use. Empiric narrow-spectrum antibiotic therapy may still be appropriate. Disclosures All authors: No reported disclosures.

Complicated urinary tract infection

‘Complicated’ urinary tract infection (UTI) indicates infection occurring in anatomically or functionally abnormal urinary tract. Infections are not only more likely in such circumstances, but they are more likely to lead to complications such as acute pyelonephritis, and are frequently more difficult to eradicate, requiring more prolonged antimicrobial therapy. Some causes may be associated with susceptibility to specific micro-organisms. There may occasionally be a limited place for prophylactic therapy.

Urinary Tract Infections

There are several terms important to a discussion of urinary tract infection (UTI). Bacteriuria is bacteria in the urine. Significant bacteriuria is at least 105 bacteria/mL of voided urine. Asymptomatic bacteriuria is bacteria in the urine without symptoms associated with urinary tract infection. Urinary tract infection is bacteriuria (or funguria) and symptoms associated with upper UTI or lower UTI (or both). UTI s are sometimes characterized as asymptomatic or symptomatic, in which case asymptomatic UTI is synonymous with asymptomatic significant bacteriuria. Uncomplicated UTI is infection of a physiologically and anatomically normal urinary tract. Complicated UTI is infection of a physiologically or anatomically abnormal urinary tract. Cystitis is lower UTI typically associated with urinary frequency, dysuria, or urgency. Acute pyelonephritis is upper UTI of recent onset with renal involvement, often associated with fever, chills, flank pain, or nausea. Diagnosis and treatment of specific infections are also reviewed.