Concordance Between Antibiotic Resistance Genes and Susceptibility in Symptomatic Urinary Tract Infections

David Baunoch; Natalie Luke; Dakun Wang; Annah Vollstedt; Xinhua Zhao; Dicken S C Ko; Shuguang Huang; Patrick Cacdac; Larry T Sirls

doi:10.2147/IDR.S323095

Concordance Between Antibiotic Resistance Genes and Susceptibility in Symptomatic Urinary Tract Infections

Infect Drug Resist. 2021 Aug 19:14:3275-3286. doi: 10.2147/IDR.S323095. eCollection 2021.

Authors

David Baunoch^{1

2}, Natalie Luke², Dakun Wang³, Annah Vollstedt⁴, Xinhua Zhao⁵, Dicken S C Ko⁶, Shuguang Huang⁵, Patrick Cacdac², Larry T Sirls⁴

Affiliations

¹ Research/Development, Pathnostics, Irvine, CA, USA.
² Clinical Affairs, Pathnostics, Irvine, CA, USA.
³ Medical Writing, Stat4ward, Pittsburgh, PA, USA.
⁴ Women's Urology and Pelvic Health Center, Beaumont Hospital, Royal Oak, MI, USA.
⁵ Statistics, Stat4ward, Pittsburgh, PA, USA.
⁶ Department of Bio Med Surgery, Warren Alpert Medical School of Brown University, Providence, RI, USA.

Abstract

Purpose: Studies have shown that multiple genes influence antibiotic susceptibility, but the relationship between genotypic and phenotypic antibiotic susceptibility is unclear. We sought to analyze the concordance between the presence of antibiotic resistance (ABR) genes and antibiotic susceptibility results in urine samples collected from patients with symptomatic urinary tract infection (UTI).

Patients and methods: Urine samples were collected from patients presenting to 37 geographically disparate urology clinics across the United States from July 2018 to February 2019. Multiplex polymerase chain reaction was used to detect 27 ABR genes. In samples containing at least one culturable organism at a concentration of ≥ 10⁴ cells per mL, pooled antibiotic susceptibility testing (P-AST), which involves simultaneous growing all detected bacteria together in the presence of antibiotic and then measure susceptibility, was performed against 14 antibiotics. The concordance rate between the ABR genes and the P-AST results was generated for the overall group. The concordance rates for each antibiotic between monomicrobial and polymicrobial infection were compared using chi-square test.

Results: Results from ABR gene detection and P-AST of urine samples from 1155 patients were included in the concordance analysis. Overall, there was a 60% concordance between the presence or absence of ABR genes and corresponding antimicrobial susceptibility with a range of 49-78% across antibiotic classes. Vancomycin, meropenem, and piperacillin/tazobactam showed significantly lower concordance rates in polymicrobial infections than in monomicrobial infections.

Conclusion: Given the 40% discordance rate, the detection of ABR genes alone may not provide reliable data to make informed clinical decisions in UTI management. However, when used in conjunction with susceptibility testing, ABR gene data can offer valuable clinical information for antibiotic stewardship.

Keywords: antibiotic resistance; antibiotic resistance genes; antibiotic susceptibility test; bacteria; culture; polymerase chain reaction; urinary tract infection.