Urinary Tract Infections After Urogynecologic Surgery: Risk Factors, Timeline, and Uropathogens

Abstract

ABSTRACT Postoperative urinary tract infection (PO-UTI) is seen in 6.4%–32% of stress urinary incontinence (SUI) and/or pelvic organ prolapse (POP) surgeries despite perioperative antibiotic prophylaxis. Postoperative complications associated with PO-UTI include increased mortality and longer hospitalization. Increasing prevalence of resistance to antibiotics and antibiotic stewardship principles necessitate both the improvement of infection prevention strategies and judicious antibiotic prescriptions. Four factors are known to increase PO-UTI risk: (1) recurrent UTI (RUTI) history, (2) preoperative UTI, (3) day-of-surgery UTI, and (4) prolonged postoperative catheterization. This study intended to determine (1) risk factors of PO-UTI and PO-RUTI, (2) preoperative and postoperative UTI temporal distribution, and (3) detected uropathogens in a large database. The study used medical record data of all SUI/POP surgical procedures performed in the Kaiser Southern California Hospital system from January 1, 2008 to December 31, 2016 for women 18 years of age or older. Procedures used Current Procedural Terminology codes for identifying and subcategorizing surgical procedures and their route (SUI or POP; abdominal or vaginal, respectively). The study-wide definition of UTI was as follows: (1) positive standard urine culture of greater than 105 CFU/mL of ≤2 uropathogens, or (2) prescription of urinary antibiotics prescribed for the indication of UTI symptoms. The analysis consisted of 21,063 urogynecologic surgical procedures performed on 20,051 women (33,626 POP and/or SUI procedures), with 22,641 UTI events being diagnosed in 10,091 women. Mean age was 56.9 years, and mean BMI was 29.1. The cohort underwent surgery for only SUI (35.4%), only POP (32.7%), or POP/SUI combined (31.9%). In the 13.5 months postoperatively, 11,976 UTIs were diagnosed in 6733 women. The first month experienced a sharp increase compared with the preoperative year, the second month increased further, and the third month showed leveling of PO-UTI incidence. Prescribed antibiotics captured most UTI events (13,337 or 58.3%). Prescribed antibiotics, in order of most-prescribed to least-prescribed, were as follows: ciprofloxacin (33.7%), cephalexin (21.4%), nitrofurantoin (20.4%), and sulfamethoxazole-trimethoprim (17.6%). The study determined that most PO-UTIs occurred within the first 2 months, with many of these being diagnosed within 2 weeks of surgery. For those patients already having a history of RUTI, RUTI significantly increases in postoperative year 1 when compared with the preoperative year. All patients undergoing SUI procedures had increased PO-RUTI risks compared with their POP-only group peers. Escherichia coli was the most common pathogen found. Risk and event timing were affected by surgical indication: although surgery for only SUI had a lower 6-week PO-UTI risk, it was counterintuitively associated with a higher PO-RUTI risk. Multivariate regression revealed predictable risk factors for PO-UTI: OAB, history of diabetes, history of preoperative UTI within 6 weeks of surgery, history of RUTI, stent and catheter placement. A more confusing finding was the association of a vaginal estrogen prescription with increased short-term PO-UTI risk, possibly related to its use in women with a history of RUTI, but more probably related to the postmenopausal status of many of the women in the dataset. The study recommends preoperative assessment with the purpose of identifying and eliminating UTIs within 6 weeks before surgery, as well as development of protocols for enhanced prophylaxis for women at increased risk such as diabetics and women with preoperative RUTI.