The association of a reduced susceptibility to moxifloxacin in causative Clostridium (Clostridioides) difficile strain with the clinical outcome of patients.

OBJECTIVES: To investigate the relationship between Clostridium (Clostridioides) difficile strain characteristics and C. difficile infection (CDI) outcome. METHODS: Between October and December 2017, 16 hospitals collected epidemiological data according to the European Centre for Disease Prevention and Control (ECDC) surveillance protocol for CDI. C. difficile isolates were characterized by ribotyping, toxin genes detection and antibiotic susceptibility testing to metronidazole, vancomycin and moxifloxacin. RESULTS: The overall mean CDI incidence density was 4.5 [95% CI 3.6-5.3] cases per 10,000 patient-days. From the 433 CDI cases, 330 (76.2%) were healthcare-associated, 52 (12.0%) cases were community-associated or of unknown origin and 51 (11.8%) CDI cases recurrent; a complicated course of CDI was reported in 65 cases (15.0%). Eighty-eight (20.3%) of patients died and 59 of them within 30 days after the CDI diagnosis. From the 379 C. difficile isolates, the most prevalent PCR ribotypes were 001 (n = 127, 33.5%) and 176 (n = 44, 11.6%). A total of 186 (49.1%) isolates showed a reduced susceptibility to moxifloxacin (> 4 mg/L) and 96.4% of them had Thr82Ile in the GyrA. Nineteen isolates revealed reduced susceptibility to metronidazole and two isolates to vancomycin (> 2 mg/L). A fatal outcome was associated with a reduced susceptibility to moxifloxacin, the advanced age of the patients and a complicated course of CDI (p<0.05). No association between ribotype, binary toxin and a reduced susceptibility to moxifloxacin and complicated course or recurrent CDI was found. CONCLUSIONS: A reduced susceptibility to moxifloxacin, in causative C. difficile strains was associated with fatal outcome of the patients, therefore it is an important marker in surveillance of CDI.

Strong antimicrobial activity of xanthohumol and other derivatives from hops (Humulus lupulus L.) on gut anaerobic bacteria.

Anaerobic bacteria, such as Bacteroides fragilis or Clostridium perfringens, are part of indigenous human flora. However, Clostridium difficile represents also an important causative agent of nosocomial infectious antibiotic-associated diarrhoea. Treatment of C. difficile infection is problematic, making it imperative to search for new compounds with antimicrobial properties. Hops (Humulus lupulus L.) contain substances with antibacterial properties. We tested antimicrobial activity of purified hop constituents humulone, lupulone and xanthohumol against anaerobic bacteria. The antimicrobial activity was established against B. fragilis, C. perfringens and C. difficile strains according to standard testing protocols (CLSI, EUCAST), and the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were calculated. All C. difficile strains were toxigenic and clinically relevant, as they were isolated from patients with diarrhoea. Strongest antimicrobial effects were observed with xanthohumol showing MIC and MBC values of 15-107 µg/mL, which are close to those of conventional antibiotics in the strains of bacteria with increased resistance. Slightly higher MIC and MBC values were obtained with lupulone followed by higher values of humulone. Our study, thus, shows a potential of purified hop compounds, especially xanthohumol, as alternatives for treatment of infections caused by select anaerobic bacteria, namely nosocomial diarrhoea caused by resistant strains.

Emergence of fluoroquinolone resistance in Escherichia coli isolates at the department of clinical hematology.

The aim of this study was to evaluate the dependence of Escherichia coli resistance to fluoroquinolones on their use in the outpatients and inpatients in the Hradec Kralove region of the Czech Republic. Data on inpatient fluoroquinolones use were obtained from the database of the Charles University Teaching Hospital Pharmacy and expressed as defined daily dose per 100 beds - days (DBD). Data on outpatient prescriptions were obtained from the database of the General Health Insurance Company and expressed in defined daily doses per 1000 clients per day (DID). Escherichia coli strains were isolated from samples of urine of both community and hospitalized patients suffering from acute bacterial urinary tract infection, examined using aerobic cultivation, and determined by standard biochemical procedures. The utilization of fluoroquinolones in inpatients has significantly (p < 0.01) increased from 2.73 DBD in 2001 to 4.89 DBD in 2006. In outpatients, fluoroquinolone utilization has also increased significantly from 0.29 DID to 1.15 DID (p < 0.01). In the same period, 11,856 Escherichia coli strains were isolated from inpatients and outpatients with urinary tract infection and tested for the susceptibility to fluoroquinolones. Resistance increased significantly (p < 0.01), both in the hospital (from 2% to 10%) and in the community (from 1% to 11%). The development of Escherichia coli resistance to fluoroquinolones correlates significantly with their utilization both in hospital (r = 0.996, p = 0.005) and in the community (r = 0.878, p = 0.029). Results of this study shows the impact of fluoroquinolone utilization on Escherichia coli resistance, and support the need of controlled use of these effective antibiotics.