Minori Matsumoto

Correlation of Overexpression of Efflux Pump Genes with Antibiotic Resistance in Escherichia coli Strains Clinically Isolated from Urinary Tract Infection Patients

ABSTRACT Escherichia coli is one of the most common pathogens in urinary tract infections (UTIs), and antibiotic resistance in E. coli is becoming a serious problem in treating UTI. Efflux system overexpression is reported to contribute to E. coli resistance to several antibiotics. This study investigated the correlation of antibiotic susceptibilities with the overexpression of the efflux pump genes such as marA, yhiU, yhiV, and mdfA and with risk factors for antibiotic resistance in E. coli isolated from UTI patients. We examined the expression level of efflux pump genes using quantitative real-time reverse transcription-PCR (qRT-PCR). We also tested the in vitro susceptibilities to 12 kinds of antibiotics in 64 clinical strains of E. coli isolated from UTI patients. By multivariate analyses we revealed significant relationships between the overexpression of (i) marA and MICs of cefepime (FEP) and nalidixic acid (NAL), (ii) yhiV and MICs of minocycline (MIN), and (iii) mdfA and MICs of sitafloxacin (STX). In our investigation of the efflux pump genes, risk factors such as gender and the previous use of fluoroquinolones correlated with the overexpression of marA, and indwelling catheter use correlated with the overexpression of mdfA. In conclusion, we demonstrated that the increased expression of efflux pump genes such as marA and mdfA can lead to fluoroquinolone resistance in E. coli. These results contribute to our knowledge of the efflux system and raise the possibility of developing new agents, such as efflux pump inhibitors (EPIs), to antibiotic-resistant E. coli.

Relationship between urinary tract infection categorization and pathogens' antimicrobial susceptibilities.

Background: Urinary tract infections (UTIs) can be hard to treat and treatment plans need to include accurate categorization such as uncomplicated or complicated UTI, or catheterized or uncatheterized UTI. We investigated the antibiotic susceptibilities of representative uropathogens in UTI categories. Methods: We isolated uropathogens and analyzed their antimicrobial susceptibilities according to UTI categorization such as: (1) urology outpatients, urology inpatients, or other department inpatients; (2) uncomplicated or complicated UTIs; (3) upper or lower UTIs, and (4) non-catheterized or catheterized UTIs. Results:Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa were representative uropathogens. Susceptibilities to levofloxacin (LVFX) in E. coli in urology outpatients (p = 0.0179), those to ceftadizime in E. coli in other department inpatients (p = 0.0327), and those to LVFX in E. faecalis in complicated UTI (p = 0.0137) significantly decreased in these 3 years compared with the previous 3 years. Susceptibilities of upper UTI to LVFX in E. coli were significantly lower in the recent 4 years compared to lower UTI (p = 0.0452) and those of catheterized UTI to LVFX in E. faecalis were significantly lower than in non-catheterized UTI (p = 0.0153). Conclusions: Data demonstrated different tendencies of uropathogens’ antibiotic susceptibilities according to UTI categorizations and they could be useful for planning UTI treatments.

Efficacy of combination use of Beta-lactamase inhibitor with penicillin and fluoroquinolones for antibiotic prophylaxis in transrectal prostate biopsy.

Purpose To investigate the efficacy of tazobactam/piperacillin (TAZ/PIPC) plus levofloxacin (LVFX) as a prophylactic administration in transrectal prostate biopsy (TPBX). Materials and Methods We investigated 201 consecutive patients who underwent TPBX in one Japanese hospital during the period of 2009-2010. The patients received TAZ/PIPC 4.5 g i.v. once just before and 3 hours after TPBX, plus oral LVFX 300 mg or 500 mg daily for 3 days. We examined the infectious adverse events and laboratory data (serum white blood cell [WBC] count and C-reactive protein [CRP]) before and 1 day after TPBX. Results Only one patient (0.50%) in 201 cases had febrile complications after TPBX. Serum WBC and CRP did not rise significantly on the day after TPBX compared with before TPBX (p>0.05). There was no significant difference in the rise of serum WBC and CRP before and after TPBX in the comparison of LVFX 500 mg with LVFX 300 mg in the TAZ/PIPC plus LVFX regimen. Conclusions TAZ/PIPC plus LVFX can be considered as a prophylactic regimen for preventing infectious complications in TPBX.

Mutations in the gyrA and parC genes and in vitro activities of fluoroquinolones in 114 clinical isolates of Pseudomonas aeruginosa derived from urinary tract infections and their rapid detection by denaturing high-performance liquid chromatography

Fluoroquinolone (FQ) resistance in Pseudomonas aeruginosa has spread. The purpose of this study was to investigate the correlation between representative FQ, i.e. levofloxacin (LVX), resistance and mutations in the gyrA and parC genes of P. aeruginosa clinical isolates from the urine of urinary tract infection patients and their rapid detection by denaturing high-performance liquid chromatography (DHPLC). The susceptibility to LVX of 114 clinical isolates was measured and the quinolone resistance-determining regions (QRDRs) in the gyrA and parC genes of these isolates were sequenced. DHPLC was undertaken to correlate the distinctive chromatograms with their DNA mutation patterns. Among 114 isolates tested, 22 isolates (19.3%) were resistant to LVX. Six amino acid mutations were detected (Thr83Ile, Asp87Tyr and Asp87Asn in gyrA and Ser87Leu, Ser87Trp and Glu91Arg in parC), existing alone or in combination. There were 10 kinds of mutation patterns. The presence of two or more kinds of mutation significantly correlated with LVX resistance compared with the wild-type or a single mutation (P<0.0001). DHPLC data identified the number of amino acid mutations with reproducibility distinguishable by peak number and profile of the DHPLC chromatogram. In conclusion, two or more mutations in gyrA and parC were significantly related to LVX resistance in P. aeruginosa. DHPLC facilitated the detection of resistant alleles, providing a rapid (5 min per sample), economical (96 samples per run) and reliable technique for characterising LVX resistance in P. aeruginosa. This rapid detection system could forecast LVX resistance by the DHPLC profile.

Mechanisms of and Risk Factors for Fluoroquinolone Resistance in Clinical Enterococcus faecalis Isolates from Patients with Urinary Tract Infections

ABSTRACT We examined Enterococcus faecalis strains clinically isolated from 100 patients with urinary tract infections (UTIs) for their susceptibility to levofloxacin (LVX) by measuring the MIC and investigated amino acid mutations by direct DNA sequencing, which were then correlated with LVX resistance. Next, we studied risk factors for LVX resistance, such as age, gender, and previous fluoroquinolone use, and investigated the statistical correlation of these risk factors with each amino acid mutation and LVX resistance. Of the 100 isolates tested, 14 isolates showed LVX resistance and all of these isolates had amino acid mutations. We demonstrated that 2 out of 4 mutations (Ser83-to-Ile in gyrA and Ser80-to-Ile in parC) had a significant correlation with LVX resistance. There was a significant relationship between isolates with 2 or 3 amino acid mutations and LVX resistance. In addition, we found a significant correlation between the previous use of fluoroquinolones and LVX resistance or the presence of mutations and also demonstrated that previous use of other types of antibiotics was significantly related to the presence of mutations by multivariate analysis. In conclusion, we found significant correlation between amino acid mutations in E. faecalis, LVX resistance, and risk factors such as previous use of fluoroquinolones.

Prevention of infectious complication and its risk factors after urological procedures of the upper urinary tract.

Background:Invasive upper urinary tract procedures such as retrograde pyelography (RP) or single (S-J) or double J (D-J) stenting are commonly performed to assess or treat ureteral strictures. Urinary tract infection (UTI) can result after such procedures, and prophylactic antimicrobial administration (PAA) may be necessary. This study investigated infectious complications and risk factors, focusing on PAA. Methods:We studied antimicrobial prevention in 353 upper urinary tract examinations or treatments. Procedures included S-J or D-J installation or exchange, RP and percutaneous nephrostomy. We investigated PAA and the occurrence of febrile infectious complications with respect to each procedure and attempted to find the risk factors. Results:Levofloxacin was used in 149 subjects (42.2%) and cefcapene pivoxil in 114 cases (32.3%). There were 16 febrile infectious complication cases (4.5%) after procedures, and pyuria or hydronephrosis prior to examination or treatment was an independent risk factor for infectious complication (p < 0.05) as well. Conclusions:These data showed that it is necessary to evaluate the risk factors before urological procedures of the upper urinary tract and to offer a definite preventive methodology according to these risk factors for the establishment and update of guidelines.

Clinical effectiveness and safety of tazobactam/piperacillin 4.5 g for the prevention of febrile infectious complication after prostate biopsy.

We investigated the clinical effectiveness and safety of tazobactam/piperacillin (TAZ/PIPC) in a 1:8 ratio, a β-lactamase inhibitor with penicillin antibiotic, for the prevention of febrile infectious complication after prostate biopsy. Each patient received a single dose of TAZ/PIPC 4.5 g, 30 min before the biopsy in Group 1 or TAZ/PIPC 4.5 g twice, once 30 min before and once after the biopsy (just before discharge or 5 h after the biopsy), in Group 2. Estimation of efficacy was performed within 1-month after prostate biopsy. Clinical diagnosis of febrile infectious complication was based on a body temperature elevation greater than 38 °C. Infectious complication after prostate biopsy was detected in 2.5% (4/160 patients) in Group 1 and in 0.45% (2/442 patients) in Group 2. All of the patients with febrile infectious complication had risk factors: 5 patients had voiding disturbance, 2 patients had diabetes mellitus and 1 patient had steroid dosing. In group 1, 88 patients had at least one risk factor and 72 patients had no risk factors. Of the patients with a risk factor, 4 had febrile infectious complication after prostate biopsy, but there was no significant difference between the two groups. In group 2, 87 patients had at least one risk factor and 255 patients had no risk factors. The patients with a risk factor had febrile infectious complication significantly more frequently than did patients without a risk factor (P = 0.038). Therefore, TAZ/PIPC appears to be effective as preoperative prophylaxis against the occurrence of febrile infectious complication after prostate biopsy.

Treatment of acute uncomplicated cystitis with faropenem for 3 days versus 7 days: multicentre, randomized, open-label, controlled trial

OBJECTIVES The increasing prevalence of resistant bacteria such as fluoroquinolone-resistant or extended-spectrum β-lactamase-producing strains in pathogens causing acute uncomplicated cystitis has been of concern in Japan. Faropenem sodium is a penem antimicrobial that demonstrates a wide antimicrobial spectrum against both aerobic and anaerobic bacteria. It is stable against a number of β-lactamases. METHODS We compared 3 and 7 day administration regimens of faropenem in a multicentre, randomized, open-label, controlled study. RESULTS In total, 200 female patients with cystitis were enrolled and randomized into 3 day (N = 97) or 7 day (N = 103) treatment groups. At the first visit, 161 bacterial strains were isolated from 154 participants, and Escherichia coli accounted for 73.9% (119/161) of bacterial strains. At 5-9 days after the completion of treatment, 73 and 81 patients from the 3 day and 7 day groups, respectively, were evaluated by intention-to-treat analysis; the microbiological efficacies were 58.9% eradication (43/73), 20.5% persistence (15/73) and 8.2% replaced (6/73), and 66.7% eradication (54/81), 6.2% persistence (5/81) and 7.4% replaced (6/81), respectively (P = 0.048). The clinical efficacies were 76.7% (56/73) and 80.2% (65/81), respectively (P = 0.695). Adverse events due to faropenem were reported in 9.5% of participants (19/200), and the most common adverse event was diarrhoea. CONCLUSIONS The 7 day regimen showed a superior rate of microbiological response. E. coli strains were in general susceptible to faropenem, including fluoroquinolone- and cephalosporin-resistant strains.

Comparison of Naftopidil 75 mg with Tamsulosin Hydrochloride 0.2 mg in the Treatment of Lower Urinary Tract Symptoms with Benign Prostatic Hyperplasia

Objective: To compare the efficacy of two α1‐adrenoceptor antagonists, α1D‐adrenoceptor‐selective naftopidil (Naf) 75 mg and α1A‐adrenoceptor‐selective tamsulosin hydrochloride (Tam) 0.2 mg, for the treatment of lower urinary tract symptoms (LUTS) in men with benign prostatic hyperplasia (BPH).

1155 MUTATIONS IN THE GYRA AND PARC GENES AND IN VITRO ACTIVITIES OF FLUOROQUINOLONES IN CLINICAL ISOLATES OF PSEUDOMONAS AERUGINOSA DERIVED FROM URINARY TRACT INFECTIONS AND THEIR RAPID DETECTION BY DENATURING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

a b s t r a c t Fluoroquinolone (FQ) resistance in Pseudomonas aeruginosa has spread. The purpose of this study was to investigate the correlation between representative FQ, i.e. levofloxacin (LVX), resistance and mutations in the gyrA and parC genes of P. aeruginosa clinical isolates from the urine of urinary tract infection patients and their rapid detection by denaturing high-performance liquid chromatography (DHPLC). The susceptibility to LVX of 114 clinical isolates was measured and the quinolone resistance-determining regions (QRDRs) in the gyrA and parC genes of these isolates were sequenced. DHPLC was undertaken to correlate the distinctive chromatograms with their DNA mutation patterns. Among 114 isolates tested, 22 isolates (19.3%) were resistant to LVX. Six amino acid mutations were detected (Thr83Ile, Asp87Tyr and Asp87Asn in gyrA and Ser87Leu, Ser87Trp and Glu91Arg in parC), existing alone or in combination. There were 10 kinds of mutation patterns. The presence of two or more kinds of mutation significantly correlated with LVX resistance compared with the wild-type or a single mutation (P < 0.0001). DHPLC data identified the number of amino acid mutations with reproducibility distinguishable by peak number and profile of the DHPLC chromatogram. In conclusion, two or more mutations in gyrA and parC were significantly related to LVX resistance in P. aeruginosa. DHPLC facilitated the detection of resistant alleles, providing a rapid (5 min per sample), economical (96 samples per run) and reliable technique for characterising LVX resistance in P. aeruginosa. This rapid detection system could forecast LVX resistance by the DHPLC profile.