Improved bacterial identification directly from urine samples with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) contributes to rapid identification of pathogens in the clinic but has not yet performed especially well for Gram-positive cocci (GPC) causing complicated urinary tract infection (UTI). The goal of this study was to investigate the possible clinical use of MALDI-TOF MS as a rapid method for bacterial identification directly from urine in complicated UTI. METHODS: MALDI-TOF MS was applied to urine samples gathered from 142 suspected complicated UTI patients in 2015-2017. We modified the standard procedure (Method 1) for sample preparation by adding an initial 10 minutes of ultrasonication followed by centrifugation at 500 g for 1 minutes to remove debris such as epithelial cells and leukocytes from the urine (Method 2). RESULTS: In 133 urine culture-positive bacteria, the rate of corresponded with urine culture in GPC by MALDI-TOF MS in urine with standard sample preparation (Method 1) was 16.7%, but the modified sample preparation (Method 2) significantly improved that rate to 52.2% (P=.045). Method 2 also improved the identification accuracy for Gram-negative rods (GNR) from 77.1% to 94.2% (P=.022). The modified Method 2 significantly improved the average MALDI score from 1.408±0.153 to 2.166±0.045 (P=.000) for GPC and slightly improved the score from 2.107±0.061 to 2.164±0.037 for GNR. CONCLUSION: The modified sample preparation for MALDI-TOF MS can improve identification accuracy for complicated UTI causative bacteria. This simple modification offers a rapid and accurate routine diagnosis for UTI, and may possibly be a substitute for urine cultures.

[The Deveroppment of Screening Methods Using the Disk Diffusion Method for Carbapenemase-producing Enterobacteriaceae].

Carbapenem-resistant Enterobacteriaceae (CRE) are increasing globally. Particularly, carbapenemase-producing Enterobacteriaceae (CPE) are of concern. Rapid and accurate detection of these strains is critical for appropriate antimicrobial use and hospital infection control. In the present study, criteria for CPE screening were examined using a carbapenem susceptibility disk. Carbapenemase producers showed minimal inhibition zones for faropenem (5 µg): 6-12 mm (mean: 6.9 mm). Some strains with the IMP-6 genotype showed inhibition zones of >30 mm for imipenem (10 µg) and biapenem (10 µg). All strains that formed inhibition zones for FRPM had the IMP-6 genotype. The cut off values of carbapenemase-producers, determined by ROC analysis, were 12 mm for FRPM, 24 mm for meropenem (10 µg), 29 mm for BIPM, 25 mm for doripenem (10 µg), 26 mm for IPM, and 24 mm for panipenem (10 µg). Thus, the sensitivity was the highest (100%) for FRPM. Specificities were 93.44% for MEPM and DRPM and 85.25% for FRPM. Consequently, a drug sensitivity test using FRPM (5 µg) disks facilitates simple and accurate CPE screening.

Recurrent Fever due to Helicobacter cinaedi Infection during R-CHOP Chemotherapy in Diffuse Large B-Cell Lymphoma: Case Report and Literature Review.

Fever due to Helicobacter cinaedi bacteremia under chemotherapy has not been widely recognized among clinicians. We experienced a 72-year-old man with diffuse large B-cell lymphoma, who was complicated with H. cinaedi bacteremia-induced fever under R-CHOP chemotherapy. We summarized 6 cases including ours, suggesting that fever without neutropenia developing around day 6 from starting chemotherapy is a possible symptom caused by H. cinaedi bacteremia. We should discriminate fever due to H. cinaedi bacteremia if fever emerged before myelosuppression in the course of chemotherapy.

Risk Factors for the Acquisition of Enterococcus faecium Infection and Mortality in Patients with Enterococcal Bacteremia: A 5-Year Retrospective Analysis in a Tertiary Care University Hospital.

The incidence of bacteremia caused by Enterococcus faecium, which is highly resistant to multiple antibiotics, is increasing in Japan. However, risk factors for the acquisition of E. faecium infection and mortality due to enterococcal bacteremia are not well known. We compared demographic, microbiological, and clinical characteristics using a Cox regression model and univariate analysis. We performed a multivariate analysis to identify risk factors for patients treated between 2014 and 2018. Among 186 patients with enterococcal bacteremia, two groups included in the Kaplan-Meier analysis (E. faecalis (n = 88) and E. faecium (n = 94)) showed poor overall survival in the E. faecium group (HR: 1.92; 95% confidence interval: 1.01-3.66; p = 0.048). The median daily antibiotic cost per patient in the E. faecium group was significantly higher than that in the E. faecalis group ($23 ($13-$34) vs. $34 ($22-$58), p < 0.001). E. faecium strains were more frequently identified with previous use of antipseudomonal penicillins (OR = 4.04, p < 0.001) and carbapenems (OR = 3.33, p = 0.003). Bacteremia from an unknown source (OR = 2.79, p = 0.025) and acute kidney injury (OR = 4.51, p = 0.004) were associated with higher risks of 30-day mortality in patients with enterococcal bacteremia. Therefore, clinicians should provide improved medical management, with support from specialized teams such as those assisting antimicrobial stewardship programs.

Impact of Cefazolin Shortage on Clinical Outcomes of Adult Patients with Bacteremia Caused by Methicillin-Susceptible Staphylococcus aureus in a Tertiary Care University Hospital.

Cefazolin is an essential antibiotic used for treating bacteremia; in particular, it is recommended as a first-line agent for infections caused by methicillin-susceptible Staphylococcusaureus (MSSA). In March 2019, problems with a major antibiotic supplier caused a critical shortage of cefazolin in Japan; however, the impact of the cefazolin shortage on clinical outcomes remains unknown. This study aimed to evaluate the effect of the cefazolin shortage in patients with MSSA bacteremia. Data from 75 patients were compared between the pre-shortage (March 2018-January 2019, n = 39) and post-shortage (March 2019-January 2020, n = 36) periods. There were no significant differences in the demographic characteristics between the two groups, and the cefazolin shortage did not worsen clinical outcomes such as adverse drug reactions, treatment failure, and 30-day mortality. In the post-shortage group, ampicillin/sulbactam and benzylpenicillin were more frequently administered as alternative antibiotics for empirical and definitive therapy (10% vs. 31%, p = 0.042; 0% vs. 19%, p = 0.004, respectively). Multivariate analysis revealed that the broad-spectrum antibiotics for definitive therapy, such as antipseudomonal penicillin, were associated with treatment failure in patients with MSSA bacteremia (OR = 17, p = 0.003). Hence, narrow-spectrum antibiotics should be prescribed for MSSA bacteremia as alternatives during a cefazolin shortage.

The Antimicrobial Resistance Characteristics of Imipenem-Non-Susceptible, Imipenemase-6-Producing Escherichia coli.

Imipenemase-6 (IMP-6) type carbapenemase-producing Enterobacteriaceae is regarded as dangerous due to its unique lack of antimicrobial susceptibility. It is resistant to meropenem (MEPM) but susceptible to imipenem (IPM). In addition to carbapenemase, outer membrane porins and efflux pumps also play roles in carbapenem resistance by reducing the antimicrobial concentration inside cells. Extended-spectrum ß-lactamase (ESBL) is transmitted with IMP-6 by the plasmid and broadens the spectrum of antimicrobial resistance. We collected 42 strains of IMP-6-producing Escherichia coli and conducted a molecular analysis of carbapenemase, ESBL, porin, efflux, and epidemiological characteristics using plasmid replicon typing. Among the 42 isolates, 21 strains were susceptible to IPM (50.0%) and 1 (2.4%) to MEPM. Seventeen strains (40.5%) co-produced CTX-M-2 type ESBL. We found that the relative expression of ompC and ompF significantly correlated with the MIC of IPM (p = 0.01 and p = 0.03, respectively). Sixty-eight% of CTX-M-2-non-producing strains had IncI1, which was significantly different from CTX-M-2-producing strains (p < 0.001). In conclusion, 50.0% of our IMP-6-producing strains were non-susceptible to IPM, which is different from the typical pattern and can be attributed to decreased porin expression. Further studies investigating other types of carbapenemase are warranted.

How Does Antimicrobial Stewardship Affect Inappropriate Antibiotic Therapy in Urological Patients?

Antimicrobial stewardship teams (ASTs) have been well-accepted in recent years; however, their clinical outcomes have not been fully investigated in urological patients. The purpose of this study was to evaluate the outcomes of intervention via a retrospective review of urological patients, as discussed in the AST meetings, who were treated with broad-spectrum antibiotics between 2014 and 2018 at the Department of Urology, Kobe University Hospital in Japan. Interventions were discussed in AST meetings for patients identified by pharmacists as having received inappropriate antibiotic therapy. The annual changes in numbers of inappropriate medications and culture submissions over five years at the urology department were statistically analyzed. Among 1,033 patients audited by pharmacists, inappropriate antibiotic therapy was found in 118 cases (11.4%). The numbers of inappropriate antibiotic use cases and of interventions for indefinite infections had significantly decreased during the study period (p = 0.012 and p = 0.033, respectively). However, the number of blood and drainage culture submissions had significantly increased (p = 0.009 and p = 0.035, respectively). Our findings suggest that urologists have probably become more familiar with infectious disease management through AST intervention, leading to a decrease in inappropriate antibiotic use and an increase in culture submissions.

[Comparison of nine second- and third-generation anti-cyclic citrullinated peptide antibody assays for the diagnosis of rheumatoid arthritis].

The aim of this study was to compare the diagnostic and analytical performances of nine anti-cyclic citrullinated peptide (CCP) antibody assays. Anti-CCP antibody titers were measured in sera from 89 patients with rheumatoid arthritis (RA), 121 with rheumatic diseases other than RA (non-RA), 47 with osteoarthritis (OA), 142 with chronic inflammatory diseases (CID) and 168 healthy subjects. Reproducibility, sensitivity, specificity, correlation and concordance rate of the nine assays were compared. Coefficients of variations of within-run and between-run reproducibility at two different concentrations for each assay ranged from 0.7 to 8.5% and from 0.6 to 8.3%, respectively. With our proposed optimal cut-off value for the third-generation assay, concordance rates were 96.8~99.6%. The range of sensitivity was 75.3~78.7% and the ranges of specificity for non-RA, OA, CID, and healthy subjects were 93.4~97.5%, 97.9%, 96.5~98.6% and 98.8~100%, respectively. However, several discrepant samples were detected and their titer levels were about 3 times higher than the normal upper limit in the 2010 RA classification criteria. Good positive correlations were observed for parts of the second-generation assay. Our study showed that each of the nine assays has good reproducibility and high diagnostic accuracy, and is thus equally useful for the diagnosis of RA.