title: Multidrug resistant bacteriuria before percutaneous nephrolithotomy predicts for postoperative infectious complications.
abstract: OBJECTIVE
  Multidrug resistant (MDR) uropathogens are increasing in prevalence and may contribute to significant morbidity after percutaneous nephrolithotomy (PCNL). We investigate the presence of MDR bacteriuria and occurrence of postoperative infectious complications in patients who underwent PCNL at our institution.
  
  
  METHODS
  Retrospective review was performed of 81 patients undergoing PCNL by a single surgeon (RLS) between 2009 and 2013. Patient demographics, comorbidities, stone parameters on imaging, and microbial data were compiled. MDR organisms were defined as resistant to three or more of the American Urological Association Best Practice Statement antimicrobial classes for PCNL. Postoperative complications were graded by Clavien score and European Association of Urology infection grade. Univariate comparisons were analyzed between patients with and without a postoperative infectious complication. Multivariate logistic regression was performed to determine significant predictor variables for postoperative infectious complications.
  
  
  RESULTS
  Of the 81 patients undergoing PCNL, 41/81 (51%) had positive preoperative urine culture, 24/81 (30%) had positive MDR urine culture, and 16/81 (19%) had a postoperative infectious complication. Multivariate analysis revealed a positive preoperative MDR urine culture significantly increased the risk of postoperative infectious complication (odds ratio [OR]=4.89, 95% confidence interval [CI] 1.134-17.8, P=0.016). The presence of more than one access tract during PCNL also predicted for infectious complications (OR=7.5, 95% CI 2.13-26.4, P=0.003) Of the 16 patients with a postoperative infection 3 (18%) had postoperative urine cultures discordant with the preoperative urine cultures.
  
  
  CONCLUSIONS
  Our institution demonstrated a relatively high prevalence of MDR bacteriuria in patients undergoing PCNL and that MDR is a significant risk factor for postoperative infectious complications despite appropriate preoperative antibiotics. Further investigations regarding prophylaxis modalities and infection prevention strategies are needed.
authors.affiliation: 1 Department of Urology, University of California San Diego Health System , San Diego, California.
authors.forename: Nishant
authors.initials: N
authors.lastname: Patel
authors.forename: William
authors.initials: W
authors.lastname: Shi
authors.forename: Michael
authors.initials: M
authors.lastname: Liss
authors.forename: Omer
authors.initials: O
authors.lastname: Raheem
authors.forename: David
authors.initials: D
authors.lastname: Wenzler
authors.forename: Craig
authors.initials: C
authors.lastname: Schallhorn
authors.forename: Linsday
authors.initials: L
authors.lastname: Kiyama
authors.forename: Charles
authors.initials: C
authors.lastname: Lakin
authors.forename: Michele
authors.initials: M
authors.lastname: Ritter
authors.forename: Roger L
authors.initials: RL
authors.lastname: Sur
mesh_terms: D000328:Adult; D000368:Aged; D001437:Bacteriuria / Q000453:epidemiology* / Q000382:microbiology; D015331:Cohort Studies; D015897:Comorbidity; D024901:Drug Resistance, Multiple, Bacterial; D004927:Escherichia coli Infections / Q000453:epidemiology*; D005260:Female; D005334:Fever / Q000453:epidemiology*; D006801:Humans; D007669:Kidney Calculi / Q000601:surgery*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009403:Nephrostomy, Percutaneous; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D018805:Sepsis / Q000453:epidemiology*; D018746:Systemic Inflammatory Response Syndrome / Q000453:epidemiology*; D014572:Urology