Identification, epidemiological relatedness, and biofilm formation of clinical Chryseobacterium indologenes isolates from central Taiwan.

The clinical impact of Chryseobacterium indologenes infection is increasing; nevertheless, most studies had been conducted in northern Taiwan, but rarely in central Taiwan. Using 16S rRNA gene sequencing, 34 isolates of C. indologenes were identified at the Central Region Hospital Alliance between 2007 and 2011. Vitek 2 and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) methods were compared for the feasibility to identify this bacterium. Drug susceptibility test, biofilm formation, and pulsed-field gel electrophoresis (PFGE) were also performed. All isolates were collected from hospitalized patients with an average age of 70.8 ± 18.5 years. The most prevalent sample was urine (50.0%), followed by sputum (32.4%). The accuracy rate of species-level identification reached 94.1% using the Vitek 2 method and 85.3% using the MALDI-TOF MS method. All of the isolates were resistant to gentamicin, amikacin, ceftriaxone, chloramphenicol, colistin, and imipenem, but completely susceptible to minocycline. While analyzing biofilm-forming ability, 38.2% (13/34) of C. indologenes isolates displayed a positive phenotype using the Luria-Bertani (LB) medium. However, 80.0% (4/5) of invasive isolates were biofilm producers. Based on PFGE analysis, several clusters were found, and the possible intrahospital spread of this bacterium in this area could not be excluded. Both Vitek 2 and MALDI-TOF MS methods showed good ability in the determination of C. indologenes. Among the examined drugs, minocycline was the most potent one. As many as 38.2% C. indologenes isolates showed biofilm-forming ability. PFGE analyses revealed the possible intrahospital transmission of this bacterium in central Taiwan.

Chang YC ，Lo HH ，Hsieh HY ，Chang SM ... -  《-》

Identification, characterization, and biofilm formation of clinical Chryseobacterium gleum isolates.

Chryseobacterium gleum is not commonly isolated from clinical source(s). Using 16S rRNA gene sequencing, we identified 15 C. gleum isolates from the Central Region Hospital Alliance, Taiwan, which were all misidentified: 14 as Chryseobacterium indologenes and 1 as Elizabethkingia meningoseptica using the Vitek 2 GN card. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry, a rapid and clinically applicable method, was evaluated for the identification of C. gleum, and the rate of species or probable species level identification reached 13.3% and 86.6%, respectively. Using pulsed-field gel electrophoresis analysis, all C. gleum isolates from central Taiwan were found to be epidemiologically unrelated. The most prevalent sample was urine (35.7%, 5/14), followed by sputum (28.6%, 4/14), whereas 1 isolate was from an unknown source. All of the isolates were susceptible to minocycline, 93.3% susceptible to trimethoprim/sulfamethoxazole, but were completely or highly resistant to the other drugs examined. Biofilm-forming ability was observed in 40.0% (6/15) isolates using the Luria-Bertani broth. To the best of our knowledge, this is the first focusing on exploring clinical C. gleum isolates.

Lo HH ，Chang SM 《-》

Identification and epidemiological relatedness of clinical Elizabethkingia meningoseptica isolates from central Taiwan.

Elizabethkingia meningoseptica is an opportunistic pathogen. Identification of E. meningoseptica based on conventional methods is rather labor- and time-consuming. The information on epidemiological relatedness and microbiological characteristics of E. meningoseptica isolates from central Taiwan was limited. Forty E. meningoseptica isolates identified by conventional methods were collected by the Central Laboratory of Central Region Hospital Alliance between 2007 and 2011. The amplification of 16S ribosomalDNA gene by polymerase chain reaction with species-specific or universal primers following DNA sequencing was used as a standard identification method. The feasibility of Vitek 2 GN card was also evaluated. Some clinical information of the patients and the drug susceptibilities and epidemiological relatedness of the isolates were analyzed. For the 40 isolates, 39 E. meningoseptica and one Chryseobacterium indologenes were identified using 16S rDNA sequencing. Among the 39 isolates, all could be identified using species-specific primers, whereas only 84.6% could be identified by Vitek 2 GN card with excellent discrimination. All E. meningoseptica isolates were susceptible to minocycline but resistant to many drugs examined including ceftazidime, amikacin, colistin, and imipenem. The pulsed field gel electrophoresis (PFGE) patterns demonstrated that most isolates were quite genetic diversity. The patients had average age of 72.2 ± 14.5 years old (excluded one child patient of 1 year old) and 79.5% of patients were male. Twenty-three patients (59.0%) had underlying diseases. The designed species-specific primers could be used to identify E. meningoseptica with 100% of specificity and sensitivity, whereas the Vitek 2 GN card showed considerable ability in E. meningoseptica identification. The PFGE patterns showed that most isolates were genetic diversity enough to exclude the possibility of intrahospital spread.

Chang YC ，Lo HH ，Hsieh HY ，Chang SM ... -  《-》

Comparison of the Vitek MS and Bruker Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Systems for Identification of Chryseobacterium Isolates from Clinical Specimens and Report of Uncommon Chryseobacterium Infections in Humans

Matrix-assisted laser desorption ionization-time of flight mass spectrometry is becoming more popular and is replacing traditional identification methods in the clinical microbiology laboratory. We aimed to compare the Vitek mass spectrometry (MS) and Bruker Biotyper systems for the identification of Chryseobacterium isolated from clinical specimens and to report uncommon Chryseobacterium infections in humans. The microbial database from a hospital was searched for records between 2005 and 2016 to identify cultures that yielded Chryseobacterium Species identification by the Vitek MS and Bruker Biotyper systems was compared to identification by 16S rRNA gene sequencing. Over the study period, 140 Chryseobacterium isolates were included. Based on 16S rRNA gene sequencing, 78 isolates were C. indologenes, 39 were C. gleum, 12 were uncommon Chryseobacterium species (C. arthrosphaerae, C. culicis, C. cucumeris, C. bernardetii, C. artocarpi, and C. daecheongense), and the remaining 11 isolates were only identified at the genus level. The Vitek MS and Bruker Biotyper systems correctly identified 98.7% and 100% of C. indologenes isolates, respectively. While the Bruker Biotyper accurately identified 100% of C. gleum isolates, the Vitek MS system correctly identified only 2.6% of isolates from this species. None of the uncommon Chryseobacterium species were successfully identified by either of these two systems. The overall accuracies of Chryseobacterium identification at the species level by the Vitek MS and Bruker Biotyper systems were 60.5% and 90.7%, respectively. An upgrade and correction of the Vitek MS and Bruker Biotyper databases is recommended to correctly identify Chryseobacterium species.

Lin JN ，Teng SH ，Lai CH ，Yang CH ，Huang YH ，Lin HF ，Lin HH ... -  《-》

Clinical and epidemiological features of Chryseobacterium indologenes infections: analysis of 215 cases.

This study investigates the clinical and epidemiological features of Chryseobacterium indologenes infections and antimicrobial susceptibilities of C indologenes. With 215 C indologenes isolates between January 1, 2004 and September 30, 2011, at a medical center, we analyzed the relationship between the prevalence of C indologenes infections and total prescription of colistin and tigecycline, clinical manifestation, antibiotic susceptibility, and outcomes. Colistin and tigecycline were introduced into clinical use at this medical center since August 2006. The increasing numbers of patients with C indologenes pneumonia and bacteremia correlated to increased consumption of colistin (p = 0.018) or tigecycline (p = 0.049). Among patients with bacteremia and pneumonia, the in-hospital mortality rate was 63.6% and 35.2% (p = 0.015), respectively. Administration of appropriate antibiotics showed significant benefit in 14-day survival in patients with C indologenes bloodstream infection (p = 0.040). In bacteremic patients, old cardiovascular accident (p = 0.036) and cancer (p = 0.014) were the most common comorbidity. The most common co-infection pathogen in patients with C indologenes pneumonia was Acinetobacter baumannii (36/91, 39.6%), followed by Pseudomonas aeruginosa (23/91, 25.3%), carbapenem-resistant A baumannii (22/91, 24.2%), and Klebseilla pneumoniae (13/91, 14.3%). Antimicrobial susceptibility testing of the 215 isolates showed that trimethoprim-sulfamethoxazole was the most active agent (susceptibility rate: 87.4%), followed by cefoperazone-sulbactam (48.0%). The present study showed a trend of increasing prevalence of C indologenes infection after introduction of colistin and tigecycline usage. The bacteremia group had higher mortality rate than the pneumonia group. Increasing resistance to piperacillin-tazobactam, ceftazidime, cefepime, and newer fluoroquinolone were noticed in our analysis. Trimethoprim-sulfamethoxazole was a potential antimicrobial agent in vitro for C indologenes. To avoid collateral damage, we emphasize the importance of antibiotic stewardship program.

Chen FL ，Wang GC ，Teng SO ，Ou TY ，Yu FL ，Lee WS ... -  《-》