ABSTRACT
OBJECTIVE: To develop a multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) assay for Acinetobacter pittii typing. METHODS: Polymorphic VNTRs were searched by Tandem Repeats Finder. The distribution and polymorphism of each VNTR locus were analyzed in all the A. pittii genomes deposited in the NCBI genome database by BLAST and were evaluated with a collection of 20 well-characterized clinical A. pittii strains and one reference strain. The MLVA assay was compared with pulsed-field gel electrophoresis (PFGE) for discriminating A. pittii isolates. RESULTS: Ten VNTR loci were identified upon bioinformatic screening of A. pittii genomes, but only five of them showed full amplifiability and good polymorphism. Therefore, an MLVA assay composed of five VNTR loci was developed. The typeability, reproducibility, stability, discriminatory power, and epidemiological concordance were excellent. Compared with PFGE, the new optimized MLVA typing scheme provided the same and even greater discrimination. CONCLUSION: Compared with PFGE, MLVA typing is a faster and more standardized alternative for studying the genetic relatedness of A. pittii isolates in disease surveillance and outbreak investigation.
Subject(s)
Acinetobacter/classification , DNA Fingerprinting/methods , Acinetobacter/genetics , Electrophoresis, Gel, Pulsed-Field , Minisatellite Repeats , Polymerase Chain ReactionABSTRACT
OBJECTIVE: During 2003-2005, an outbreak of meningitis due to Neisseria meningitidis serogroup C occurred in China. With the aim to find strain clues result in the final epidemics, the ancestral strain 053442, a clinical isolate, and a carrier strain 053426 with different gene type were analyzed. METHODS: Clinical strain 053442 and carrier strain 053426 were cultured on GC agar plates under the same condition. Two-dimensional electrophoresis was performed using the pH 3-10 nonlinear IPG strips of 24 cm length, and all the protein spots were identified by matrix-assisted laser desorption/ionization time of flight spectrometry. RESULTS: 502 and 380 protein spots were identified in 053426 and 053442 respectively, relating to 266 and 202 different genes covering a wide range of cellular functions. The express volume and number of proteins involved in energy metabolism, protein synthesis and amino acid biosynthesis in 053426 were higher than in 053442. Virulence factor Opa, Opc and a series of proteins involved in pilus assembly and retraction were identified in 053442, which appear to be of primary importance in colonization and invasion of human cells. Compared to 053442, virulence protein species were less in 053426, with lower express volumes too. No Opa and Opc were detected in 053426. CONCLUSIONS: The different protein expression profiles of the clinical strain 053442 and carrier strain 053426 in the present study provide some clues of the different pathogenicity of the two strains, which may account for result in the final epidemics.
Subject(s)
Bacterial Proteins/analysis , Bacterial Typing Techniques , Disease Outbreaks , Meningitis, Meningococcal/epidemiology , Meningitis, Meningococcal/microbiology , Neisseria meningitidis, Serogroup C/isolation & purification , Proteome/analysis , China/epidemiology , Electrophoresis, Gel, Two-Dimensional , Humans , Meningitis, Meningococcal/cerebrospinal fluid , Neisseria meningitidis, Serogroup C/classification , Spectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationABSTRACT
OBJECTIVE: To identify specific proteins of Helicobacter pylori (H. pylori) that associated with gastric carcinoma. METHODS: The whole-cell proteins of H. pylori were separated by two-dimensional electrophoresis (2-DE). The protein maps of four H. pylori strains associated with gastric carcinoma and nine strains that isolated from patients with non-gastric carcinoma were then compared by ImageMaster 2D v3.1. MALDI-TOF mass spectrometry was performed to identify the proteins of interest. The proteins were searched by software mascot and identified by peptide fingerprint map. RESULTS: Three proteins seemed to be associated with gastric carcinoma including acylneuraminate cytidylyltransferase with Mowse score 79 with the sequence coverage of 32%. The other two had no unambiguous protein to match. CONCLUSION: Acylneuraminate cytidylyltransferase seemed to be a specific H. pylori protein associated with the presence of gastric carcinoma. Other two were novel proteins that might be associated with gastric carcinoma. However, the mechanism needs to be explored.
