Multi-drug resistant strains as etiological agents of urinary tract infections in patients after solid organ transplantation.

Introduction: Urinary tract infections (UTIs) caused by multi-drug resistant strains are a serious and growing problem in organ transplant (TX) recipients. Aim of the study: The aim of the study was to assess the prevalence and risk factors of UTIs caused by multi-drug resistant strains in hospitalized patients after kidney or liver transplantation in a large transplant center. Material and methods: 392 cases of UTIs in patients after kidney or liver TX hospitalized in 2014, 2015 and 2016 were analyzed. Among the assessed cases of UTIs, 66.07% occurred in women, 33.93% - in men, 80.1% - in kidney TX recipients and 19.9% - in liver TX recipients. The median age of the patients was 57.51 years and the median time since TX was 41.44 months. Results: Most episodes of UTIs were observed during the first year after TX - 121 (30.78%) of cases. A total of 506 pathogens were cultured: 345 Gram-negative bacteria (68.182%), 146 Gram-positive bacteria (28.854%) and 15 fungi (2.964%). More than one pathogen was found in 25.51% of urine cultures. Among bacteria (n=491), a resistance mechanism was detected in 166 (33.81%) pathogens (133 Gram-negative and 33 Gram-positive). The most common etiological agents were: E. coli ESBL- (23.72%), K. pneumoniae ESBL+ (17.19%), E. faecalis (11.27%) and E. faecium (7.71%). Diabetes was present in 129 (35.46%) of patients, and the number of UTI cases was similar in the group with and without diabetes. Conclusions: Compared to the general population, in hospitalized patients after kidney or liver transplantation UTIs occur more often in men and are more often caused by Gram-positive bacteria. In 33.81% of cases UTIs are caused by multi-drug resistant strains, predominantly Gram-negative bacteria.

Breaking Antimicrobial Resistance: High-Dose Amoxicillin with Clavulanic Acid for Urinary Tract Infections Due to Extended-Spectrum Beta-Lactamase (ESBL)-Producing Klebsiella pneumoniae.

BACKGROUND Carbapenems are the primary treatment for urinary tract infections (UTIs) caused by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae. However, the recurrence rate is high, and patients often require rehospitalization. We present the results of an observational study on patients with recurrent UTIs who were treated in an outpatient setting with maximal therapeutic oral doses of amoxicillin with clavulanic acid. MATERIAL AND METHODS All patients had pyuria and ESBL-producing K. pneumoniae in urine culture. The starting dosage was 2875 g of amoxicillin twice daily and 125 mg of clavulanic acid twice daily. We down-titrated the doses every 7-14 days and continued prophylactic therapy with amoxicillin/clavulanic acid at 250/125 mg for up to 3 months. We defined therapeutic failure as ESBL-positive K. pneumoniae in urine culture during therapy and recurrence as positive urine culture with the same strain within 1 month after the end of treatment. RESULTS We included 9 patients: 7 kidney graft recipients, 1 liver graft recipient, and 1 patient with chronic kidney disease. We observed no therapeutic failures and no recurrences in the study group during the study period. In 1 case, the patient experienced a subsequent UTI caused by ESBL-producing K. pneumoniae 4 months after completing the therapy. CONCLUSIONS In conclusion, it is possible to break the resistance of ESBL-producing K. pneumoniae strains with high doses of oral amoxicillin with clavulanic acid. Such treatment could be an alternative to carbapenems in select cases.