Genotyping of human Brucella melitensis biovar 3 isolated from Shanxi Province in China by MLVA16 and HOOF.

BACKGROUND: Brucellosis presents a significant economic burden for China because it causes reproductive failure in host species and chronic health problems in humans. These problems can involve multiple organs. Brucellosis is highly endemic in Shanxi Province China. Molecular typing would be very useful to epidemiological surveillance. The purpose of this study was to assess the diversity of Brucella melitensis strains for epidemiological surveillance. Historical monitoring data suggest that Brucella melitensis biovar 3 is the predominant strain associated with the epidemic of brucellosis in Shanxi Province. METHODS/PRINCIPAL FINDINGS: Multiple-locus variable-number repeat analysis (MLVA-16) and hypervariable octameric oligonucleotide fingerprinting (HOOF-print) were used to type a human-hosted Brucella melitensis population (81 strains). Sixty-two MLVA genotypes (discriminatory index: 0.99) were detected, and they had a genetic similarity coefficient ranging from 84.9% to 100%. Eighty strains of the population belonged to the eastern Mediterranean group with panel 1 genotypes 42 (79 strains) and 43 (1 strain). A new panel 1 genotype was found in this study. It was named 114 MLVAorsay genotype and it showed similarity to the two isolates from Guangdong in a previous study. Brucella melitensis is distributed throughout Shanxi Province, and like samples from Inner Mongolia, the eastern Mediterranean genotype 42 was the main epidemic strain (97%). The HOOF-printing showed a higher diversity than MLVA-16 with a genetic similarity coefficient ranging from 56.8% to 100%. CONCLUSIONS: According to the MLVA-16 and HOOF-printing results, both methods could be used for the epidemiological surveillance of brucellosis. A new genotype was found in both Shanxi and Guangdong Provinces. In areas with brucellosis, the MLVA-16 scheme is very important for tracing cases back to their origins during outbreak investigations. It may facilitate the expansion and eradication of the disease.

Genome sequencing reveals unique mutations in characteristic metabolic pathways and the transfer of virulence genes between V. mimicus and V. cholerae.

Vibrio mimicus, the species most similar to V. cholerae, is a microbe present in the natural environmental and sometimes causes diarrhea and internal infections in humans. It shows similar phenotypes to V. cholerae but differs in some biochemical characteristics. The molecular mechanisms underlying the differences in biochemical metabolism between V. mimicus and V. cholerae are currently unclear. Several V. mimicus isolates have been found that carry cholera toxin genes (ctxAB) and cause cholera-like diarrhea in humans. Here, the genome of the V. mimicus isolate SX-4, which carries an intact CTX element, was sequenced and annotated. Analysis of its genome, together with those of other Vibrio species, revealed extensive differences within the Vibrionaceae. Common mutations in gene clusters involved in three biochemical metabolism pathways that are used for discrimination between V. mimicus and V. cholerae were found in V. mimicus strains. We also constructed detailed genomic structures and evolution maps for the general types of genomic drift associated with pathogenic characters in polysaccharides, CTX elements and toxin co-regulated pilus (TCP) gene clusters. Overall, the whole-genome sequencing of the V. mimicus strain carrying the cholera toxin gene provides detailed information for understanding genomic differences among Vibrio spp. V. mimicus has a large number of diverse gene and nucleotide differences from its nearest neighbor, V. cholerae. The observed mutations in the characteristic metabolism pathways may indicate different adaptations to different niches for these species and may be caused by ancient events in evolution before the divergence of V. cholerae and V. mimicus. Horizontal transfers of virulence-related genes from an uncommon clone of V. cholerae, rather than the seventh pandemic strains, have generated the pathogenic V. mimicus strain carrying cholera toxin genes.

[Analysis on the etiological surveillance of influenza/novel influenza A (H1N1) from 2009-2010 in Shanxi Province].

OBJECTIVE: To study the epidemical characteristics of influenza/novel influenza A (H1N1) in Shanxi province from 2009 to 2010, and to provide scientific foundations for predicting and controlling the pandemic outbreak of influenza/novel influenza A (H1N1) effectively. METHODS: All samples were collected from cases that resemble influenza cases in sentinel hospital and influenza outbreak. The influenza were detected by PCR and isolated by MDCK cell culture method. Finally, Shanxi province surveillance data from May, 2009 to April, 2010 of influenza like illness (ILI) cases and pathogen detections were analyzed. RESULTS: In Shanxi province, influenza viruses kept activation in whole year. The predominant pandemic strain in 2009 was novel influenza A (H1N1) virus. The strong peak was around November, 2009 [positive rate: 58.1%, novel influenza A ( H1N1) of the total: 88.1%]. As well, the people infected influenza caused by novel influenza A (H1N1) were mainly under 59-year-old, and the higher positive rates were concentrated in the people from 5-year-old to 24-year-old. In 2010, influenza B (Victoria) viruses were mainly detected from clinical specimens and became the dominant strain. CONCLUSION: Surveillance of Influenza liue illnes, (ILI) and etiology, which can promptly reflect the influenza epidemic situation, play a significant role for understanding epidemic rule of influenza/novel influenza A (H1N1).