[Impact of the Antimicrobial Stewardship Team Intervention Focusing on Changes in Prescribing Trends and the Rate of Carbapenem-resistant P. aeruginosa].

Antimicrobial stewardship (AS) intervention strategy is a critical process in promoting appropriate antibiotic use, thus preventing unnecessarily prolonged therapy and reducing antimicrobial resistance (AMR). Although limiting unnecessary carbapenem use by AS intervention is speculated to reduce AMR, there is a lack of specific data on the efficacy of AS team (AST) intervention regarding carbapenem-resistant Pseudomonas aeruginosa (CRPA). Consequently, this study aimed to evaluate the impact of our AS strategy on carbapenem use and CRPA. The AS intervention strategy was launched in July 2017 and consisted of daily audits and feedback on carbapenem use. We evaluated the 4-year prescription trend, including the rate of switching to other antimicrobials, and the rate of CRPA and the days of therapy required prior to and after the beginning of the AST intervention. The rate of switching to narrow-spectrum antibiotics and the discontinuation of carbapenem treatment were significantly higher in the pre-intervention period compared with the post-intervention period. (7.0% vs. 14.5%; p<0.001; 54.1% vs. 50.9%; p=0.027). However, there were no significant differences in the rate of CRPA prior to and after the beginning of the AST intervention. Furthermore, there was no correlation found between consumption and resistance rate (Pearson's r=0.123). Our results suggest that it is extremely important for AST to promote de-escalation and reduce unnecessary use, while the combination of process and outcome indicators other than antimicrobial consumption and resistance rate are required for the evaluation of the AS programs.

Bacteriuria With CTX-M-8 Extended-Spectrum ß-Lactamase-Producing Escherichia coli in a Patient With Incomplete Kawasaki Disease.

We report the case of a 2-month-old infant with incomplete Kawasaki disease that presented as an apparent urinary tract infection. The patient's fever persisted despite antibiotic treatment. Intravenous immunoglobulin and aspirin therapy cured both the incomplete Kawasaki disease and bacterial pyuria. Renal sonography, voiding cystourethrography, and renal parenchyma radionuclide scanning did not detect any abnormalities. Temporary dilation of the coronary artery was noted. In a urine specimen obtained through transurethral catheterization, the growth of 105 colony-forming units/mL of extended-spectrum ß-lactamase-producing Escherichia coli was detected. Polymerase chain reaction analysis revealed that the enzyme genotype was CTX-M-8, which is a rare type in Japan. In conclusion, attention should be paid to a misleading initial presentation of fever and pyuria, which might be interpreted as urinary tract infection in patients with Kawasaki disease. Furthermore, pediatricians should consider incomplete Kawasaki disease when patients present with fever and pyuria, which are consistent with urinary tract infection, but do not respond to antibiotic treatment.

Efficacy of non-carbapenem antibiotics for pediatric patients with first febrile urinary tract infection due to extended-spectrum beta-lactamase-producing Escherichia coli.

Although carbapenem is the recommended for urinary tract infection (UTI) caused by extended-spectrum beta-lactamase (ESBL)-producing organisms, non-carbapenems have been reported to be effective for adult patients with UTI caused by ESBL-producing organisms. The purpose of this study was to evaluate the efficacy of non-carbapenems for pediatric patients with UTI due to ESBL-producing Escherichia coli (E. coli) based on the microbiologic and clinical outcomes. Fifteen children, who were treated for first febrile UTI caused by ESBL-producing E. coli were enrolled in this study. Antimicrobial susceptibilities and ESBL production were determined according to the Clinical and Laboratory Standards Institute guidelines. To detect CTX-M genes, polymerase chain reaction was performed with specific primers for blaCTX-M detection. Of the 15 enrolled patients, 10 (66.7%) were boys and 5 (33.3%) were girls, with a median age of four months. VUR was detected in six patients (40%). For detection of blaCTX-M by PCR, CTX-M-3, CTX-M-8, CTX-M-14, and CTX-M-15 were detected in five, one, eight, and one patient, respectively. Overall, 14 of the 15 isolates (93.3%) were susceptible for fosfomycin (FOM), and all isolates were susceptible for cefmetazole (CMZ), flomoxef (FMOX), and imipenem/cilastatin (IPM/CS). Of the 15 patients, 12 (80%) clinically improved without the use of carbapenems. In conclusion, even if isolates of ESBL-producing E. coli are multidrug resistant based on MIC assessment, clinical susceptibility to non-carbapenems, such as CMZ, FMOX, and FOM, is possible. Accordingly, carbapenems may not be required all the time for treatment of pediatric UTI in clinical practice.

Analysis of Staphylococcal Toxins and Clinical Outcomes of Methicillin-Resistant Staphylococcus aureus Bacteremia.

It is well known that methicillin-resistant Staphylococcus aureus (MRSA) produces many virulence factors, such as hemolysins, leukocidins, proteases, enterotoxins, exfoliative toxins, and immune-modulatory factors. The aim of study was to identify staphylococcal pathogenicity that may affect the prognosis of patients with MRSA bacteremia. We obtained 149 MRSA strains from blood cultures between January 2009 and December 2014 in our institution. We collected information on patient characteristics, laboratory data, staphylococcal toxin genes, and susceptibility of the strain toward anti-MRSA agent and analyzed them as factors contributing to 30-d mortality. The "survival" and "dead" groups consisted of 103 and 46 patients, respectively. Multiple logistic regression analysis showed a four-fold increase in the risk of mortality in patients exhibiting isolated MRSA with staphylococcal enterotoxins (SEs) genes as well as toxic shock syndrome toxin-1 (TSST-1) genes [odds ratio: 3.89; 95% confidence interval: 1.20-12.60; p=0.024]. Kaplan-Meier analysis also showed significantly higher mortality in patient with isolated MRSA with SEs and TSST-1 genes. After adjusting for confounders, the coexistence of SEs and TSST-1 were independently associated with the 30-d mortality compared with treatment and susceptibility. The coexistence of superantigenic toxin genes greatly affects the clinical course and prognosis of patients with MRSA bacteremia.

Validation of Cefazolin as Initial Antibiotic for First Upper Urinary Tract Infection in Children.

To validate the policy of administering cefazolin (CEZ) as a first-line antibiotic to children who are hospitalized with their first febrile urinary tract infection (UTI), we evaluated microbial susceptibility to CEZ and the efficacy of CEZ. The 75 enrolled children with febrile UTI were initially treated with CEZ. Switching CEZ was not required in 84% of the patients. The median fever duration, prevalence of bacteremia, prevalence of UTI caused by extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli, and median duration of hospitalization were significantly higher in the CEZ-ineffective group. The risks of vesicoureteral reflux, indication of operation, and renal scarring are not increased, even when CEZ is ineffective as a first-line antibiotic. CEZ is effective in more than 80% of pediatric patients with their first febrile UTI, but it should be switched to appropriate antibiotics considering sepsis or the ESBL-producing Enterobacteriaceae pathogen, when fever does not improve within 72 hours.

Effect of interventions by an antimicrobial stewardship team on clinical course and economic outcome in patients with bloodstream infection.

BACKGROUND: Bloodstream infections (BSIs) represent one of the most severe and clinically important conditions in the hospital setting. We have organized an interdisciplinary antimicrobial stewardship team (AST) at our hospital and performed consultations focusing on BSI patients since 2013. This study aimed to evaluate the impact of AST interventions on the diagnosis, treatment, and clinical outcomes of BSI patients. METHODS: We conducted a retrospective quasi-experimental study of BSI patients at a single Japanese university hospital. AST provided recommendations to attending physicians regarding appropriate diagnosis, therapy, and management of BSI patients after reviewing medical charts. RESULTS: We identified a total of 308 cases of BSI from January to December, 2012 (pre-intervention group) and 324 cases of BSI from April, 2013 to March, 2014 (post-intervention group). No significant differences in the in-hospital mortality or 30-day mortality rates were observed between both the groups. Inappropriate therapy was initiated in a significantly lower proportion of patients in the post-intervention group (18.5% vs. 11.4%; P = 0.012). Multivariate analysis confirmed that inappropriate therapy was significantly associated with in-hospital mortality (odds ratio, 2.62; 95% confidence interval, 1.42-4.82; P = 0.002). CONCLUSIONS: An interdisciplinary AST intervention approach decreases the use of inappropriate therapy and may improve clinical outcomes in BSI patients.

More accurate measurement of vancomycin minimum inhibitory concentration indicates poor outcomes in meticillin-resistant Staphylococcus aureus bacteraemia.

Meticillin-resistant Staphylococcus aureus (MRSA) is an important pathogen associated with community-acquired and nosocomial infections. The aim of this study was to validate the vancomycin (VAN) minimum inhibitory concentration (MIC) and administration of VAN that may affect the prognosis of patients with MRSA bacteraemia. In total, 140 clinical MRSA strains from blood cultures were collected from January 2009 to December 2013 at a university hospital in Tokyo (Japan). Patient background, their clinical situation and the susceptibility of isolates to anti-MRSA agents in all cases were reviewed, and factors contributing to 30-day mortality were analysed. Susceptibility to anti-MRSA agents was measured by a microdilution susceptibility testing method. The VAN MIC was further evaluated at 0.25 µg/mL intervals from 0.5 µg/mL to 2.0 µg/mL. Multiple logistic regression analysis revealed a 4-fold increase in mortality of patients with a VAN MIC ≥1.5 µg/mL [odds ratio (OR)=3.952, 95% confidence interval (CI) 1.471-10.614; P=0.006]. A one-score increase in the Charlson co-morbidity index resulted in a 1.2-fold increase in the risk of death (OR=1.199, 95% CI 1.054-1.364; P=0.006). However, no significant difference was found in the ratio of the VAN 24-h area under the concentration-time curve to MIC between VAN MIC ≥1.5 µg/mL and <1.5 µg/mL. A significant increase in the MICs of teicoplanin and daptomycin was observed in strains with high VAN MICs. For patients with high VAN MICs, administration of these anti-MRSA antibiotics may have a poor outcome owing to cross-resistance.

Detection of metallo-ß-lactamase genes in clinically isolated Klebsiella pneumoniae and Klebsiella oxytoca.

We detected and characterized metallo-ß-lactamase genes (blaIMP-1 and blaIMP-11) in third generation cephalosporin-resistant Klebsiella pneumoniae and Klebsiella oxytoca isolated at Showa University Hospital between January 1, 2011 and December 31, 2012. The cephalosporin-resistant K pneumoniae strains were frequently isolated from the urine, while one strain of K. pneumoniae, which was resistant to carbapenem, was isolated from the stool. We analyzed the phenotypes and genotypes of the metallo-ß-lactamase genes from the 16 strains of cephalosporin-resistant-K pneumoniae and 6 strains of -K. oxytoca isolated from the same ward. The minimum inhibitory concentrations of imipenem were below 4 µg/ml in 21 out of the 22 isolated strains. The double disc synergy test using ceftazidime and sodium mercaptoacetic acid revealed enlargements in the inhibitory zones of 14 of the 16 strains of K. pneumoniae and all 6 strains of K. oxytoca. Metallo-ß-lactamase genes were detected in all of the tested strains, with blaIMP-1 in 3 K. pneumoniae and 1 K. oxytoca, blaIMP-11 in 13 K pneumoniae and 4 K. oxytoca, and both blaIMP-1 and blaIMP-11 in one K. oxytoca. Our results indicate that third generation cephalosporin-resistant and imipenem-susceptible K. pneumoniae and K. oxytoca possess the metallo-ß-lactamase gene. The active surveillance of metallo-ß-lactamase genes should be performed in clinical laboratories. (Original).

MLST analysis of multiple antimicrobial resistant Acinetobacter baumannii.

Multi-locus sequencing typing (MLST) of Acinetobacter baumannii, isolated at Showa University Hospital, was performed between November 2010 and March 2011. A. baumannii was isolated from 15 patients. Among the 15 isolates, the STs of three isolates were able to be determined, ST76, ST92, and ST146, and belonged to Clonal Complex (CC) 92, the global epidemic clone among carbapenem resistant A. baumannii. The other 12 strains were not applicable to the MLST classification. The ST76 strain was resistant to carbapenems, aminoglycosides, and fluoroquinolones. The ST92 strain was resistant to aminoglycosides and fluoroquinolones. The ST146 strain was resistant to fluoroquinolones. The other 12 strains were susceptible to either of the drugs. Neither the metallo beta lactamase gene (IMP type or VIM2) nor the OXA23 gene was detected in carbapenem resistant A. baumannii. These results indicate that A. baumannii of CC92 has spread as the drug resistant strain in Japan. Monitoring A. baumannii using molecular epidemiology is necessary.

Evaluation in vitro of the efficacy of colistin methanesulfonate against biofilm-forming multidrug-resistant Pseudomonas aeruginosa (MDRP).

The aim of this study was to evaluate in vitro the efficacy of clinically using colistin methanesulfonate against biofilm-forming multidrug-resistant Pseudomonas aeruginosa (MDRP), with minimum inhibitory concentrations (MICs) of ciprofloxacin, imipenem, and amikacin showing ≥4, 16, and 32 µg/ml, respectively, by disk diffusion susceptibility testing (CLSI document M100-S21). The minimum eradication biofilm concentration (MBEC) of colistin methanesulfonate for strain MDRP-YMD isolated from a patient's urine, which formed a biofilm on plastic pegs attached to a microplate lid, was compared with that of P. aeruginosa ATCC27853 for quality control testing with MICs of ciprofloxacin, imipenem, and amikacin showing ≤1, 4, and 16 µg/ml, respectively. In an uneven biofilm approximately 10 µm thick, as determined with confocal laser scanning microscopy (CLSM), ratios of MBEC to MIC of colistin methanesulfonate against strains MDRP-YMD and ATCC27853 were 10.5 and 8.0, whereas those of minimum bactericidal concentration (MBC) to MIC in planktonic cells were 1.0 and 2.0 µg/ml, respectively. Morphological examination using scanning electron microscopy and CLSM verified that embedded cells in biofilm matrices of the two strains were disrupted and died under the MBEC. Therefore, bactericidal effects of colistin methanesulfonate on biofilm-forming cells of strain MDRP-YMD as well as strain ATCC27853 were significantly decreased compared with those on the planktonic cells.

To reduce catheter-related bloodstream infections: is the subclavian route better than the jugular route for central venous catheterization?

The most important targets of hospital-acquired infection control are to reduce the incidence of surgical-site, catheter-related, and ventilator-associated infections. In this report, we address previously presented infection-control strategies for central venous (CV) line catheterization, using a CV catheter-related infection surveillance system. Data concerning CV catheter insertion were collected from all facilities in our 650-bed hospital, excluding the operating and hemodialysis wards. Collected data included the insertion method, purpose, length of catheter inserted, duration of catheterization, infection rate, and complication rate. Catheter-related infection was diagnosed based on bacteriological examinations from blood cultures. The total number of catheterizations was 806 a year, and average duration of catheterization was 9.8 days. The purpose of catheterization was nutritional support in 210 cases, hemodialysis in 96 cases, cardiac support in 174 cases, and other treatments in 260 cases. In 66 cases, the purpose of CV catheter was not specified. The rate of positive cultures was 7.1%, and complications other than infection occurred in 0.5%. The main causative organisms were methicillin-resistant Staphylococcus aureus (MRSA) in 38.6%, coagulase-negative Staphylococcus epidermidis (CNS) in 33.3%, and S. aureus in 12.3% of infections. Infection rates were 3.8 per 1000 catheter-days in subclavian, 6.1 in jugular, and 15.7 in femoral vein catheterization. In high-risk departments (intensive care unit [ICU] and emergency departments) the infection rate was 5.4 for subclavian and 10.2 for jugular catheterization, whereas it was 3.6 for subclavian and 4.6 for jugular catheterization in noncritical-care departments. Considering complications such as pneumothorax, CV catheterization of the jugular vein is recommended in certain situations.