An evaluation of multidrug-resistant (MDR) bacteria in patients with urinary stone disease: data from a high-volume stone management center

To investigate the prevalence of MDR bacteria in patients with urinary stones and the risk factors for its formation. A retrospective study was performed among patients with urinary stones in Beijing Tsinghua Changgung Hospital from December 2014 to May 2018. Patients with positive urinary cultures and drug sensitivity results were included. MDR were defined as any bacteria that have resistance to at least one agent in at least three classes of antibiotics. Bacteria distribution and resistance patterns were calculated. 1655 patients with urinary stones were eligible for analysis, among which 367 patients had positive urinary culture, yielding 457 isolates of 45 species. Escherichia coli remained the most common organism with a prevalence of 29.3%, followed by Enterococcus faecalis (12.0%), Proteus mirabilis (10.5%), and Klebsiella pneumonia (6.8%). 44.4% isolates were identified as MDR. The three most common Gram-negative bacteria were Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae, with a MDR rate of 84.33%, 62.5%, and 48.39%, respectively. Drug-resistant rates were different between MDR and non-MDR in ampicillin, cefazolin, ceftriaxone, cefepime, gentamicin, amikacin, and levofloxacin (all with p value < 0.05). In multivariate analysis, indwelling catheters (OR 3.1, 95% CI 1.07–8.98) and antibiotics use in the last 3 months (OR 2.14, 95% CI 1.04–4.38) were significantly associated with MDR formation. MDR bacteria were common among patients with urinary stones in our center and achieved high drug-resistant rates in ampicillin, first-generation and part of third-generation cephalosporins, and fluoroquinolones. Indwelling catheters and antibiotics used in the last 3 months were independent risk factors for MDR formation. Tailored antibacterial strategies still should be established according to the local bacterial spectrum and patient condition.