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

BACKGROUND: The clinical impact of Chryseobacterium indologenes infection is increasing; nevertheless, most studies had been conducted in northern Taiwan, but rarely in central Taiwan. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

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.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.