Seroprevalence trend of human brucellosis and MLVA genotyping characteristics of Brucella melitensis in Shaanxi Province, China, during 2008-2020.

In this study, a total of 179,907 blood samples from populations with suspected Brucella spp. infections were collected between 2008 and 2020 and analyzed by the Rose Bengal plate test (RBPT) and serum agglutination test (SAT). Moreover, conventional biotyping, B. abortus-melitensis-ovis-suis polymerase chain reaction (AMOS-PCR), and multiple-locus variable-number tandem repeat analysis (MLVA) was applied to characterize the isolated strains. A total of 8103 (4.50%) samples were positive in RBPT, while 7705 (4.28%, 95% confidence interval (CI) 4.19-4.37) samples were positive in SAT. There was a significant difference in seroprevalence for human brucellosis over time, in different areas and different cities (districts) (χ2 = 2 = 32.23, 1984.14, and 3749.51, p < .05). The highest seropositivity (8.22% (4, 965/60393; 95% CI 8.00-8.44) was observed in Yulin City, which borders Inner Mongolia, Ningxia, and Gansu Province, China, regions that have a high incidence of human brucellosis. Moreover, 174 Brucella strains were obtained, including nine with B. melitensis bv. 1, 145 with B. melitensis bv. 3, and 20 with B. melitensis variants. After random selection, 132 B. melitensis were further genotyped using MLVA-16. The 132 strains were sorted into 100 MLVA-16 genotypes (GTs) (GT 1-100), 81 of which were single GTs represented by singular independent strains. The remaining 19 shared GTs involved 51 strains, and each GT included two to seven isolates from the Shaan northern and Guanzhong areas. These data indicated that although sporadic cases were a dominant epidemic characteristic of human brucellosis in this province, more than 38.6% (51/132) outbreaks were also found in the Shaan northern area and Guanzhong areas. The 47 shared MLVA-16 GTs were observed in strains (n = 71) from this study and strains (n = 337) from 19 other provinces of China. These data suggest that strains from the northern provinces are a potential source of human brucellosis cases in Shaanxi Province. It is urgent to strengthen the surveillance and control of the trade and transfer of infected sheep among regions.

Changes in the epidemiological characteristics of human brucellosis in Shaanxi Province from 2008 to 2020.

In the present study, surveys of case numbers, constituent ratios, conventional biotyping, and multilocus sequence typing (MLST) were applied to characterize the incidence rate and epidemiological characteristics of human brucellosis in Shaanxi Province, China. A total of 12,215 human brucellosis cases were reported during 2008-2020, for an annual average incidence rate of 2.48/100,000. The most significant change was that the county numbers of reported cases increased from 36 in 2008 to 84 in 2020, with a geographic expansion trend from northern Shaanxi to Guanzhong, and southern Shaanxi regions; the incidence rate declined in previous epidemic northern Shaanxi regions while increasing each year in Guanzhong and southern Shaanxi regions such as Hancheng and Xianyang. The increased incidence was closely related to the development of large-scale small ruminants (goats and sheep) farms in Guanzhong and some southern Shaanxi regions. Another significant feature was that student cases (n = 261) were ranked second among all occupations, accounting for 2.14% of the total number of cases, with the majority due to drinking unsterilized goat milk. Three Brucella species were detected (B. melitensis (bv. 1, 2, 3 and variant), B. abortus bv. 3/6, and B. suis bv. 1) and were mainly distributed in the northern Shaanxi and Guanzhong regions. Three known STs (ST8, ST2, and ST14) were identified based on MLST analysis. The characteristics that had not changed were that B. melitensis strains belonging to the ST8 population were the dominant species and were observed in all nine regions during the examined periods. Strengthened human and animal brucellosis surveillance and restriction of the transfer of infected sheep (goats) as well as students avoiding drinking raw milk are suggested as optimal control strategies.

The Taxonomic Status of Spermophilus in the Plague Area of Dingbian County, Shaanxi Province, China.

This study was conducted to define the taxonomic status of Spermophilus in the plague area of Dingbian County in Shaanxi Province, China, through the two-factor variance analysis of morphological characteristics, DNA barcoding, and chromosome karyotype analysis. The Spermophilus samples collected from Dingbian and Zhengxiang Baiqi Counties exhibited significant differences in their morphological measurements. All Spermophilus samples form two distinct branches in neighbor-joining (NJ) tree. One branch included the Spermophilus samples collected from Inner Mongolia, and the other branch included samples collected from the plague foci of Shaanxi Province and the Ningxia Region. The Spermophilus samples collected from Dingbian County had a chromosome number of 2n = 38 in 84.40% of all their cells. The Spermophilus species collected from the plague area of Dingbian County was categorized as Spermophilus alashanicus (S.alashamicus). The findings reported in this study are epidemiologically significant for monitoring plague in this region of west-central China.

[Effect of adjuvant therapy with Dingguier umbilical paste on intestinal flora of diarrhea infants and its action characteristics].

The applicator therapy is a unique method to treat infant diarrhea in traditional Chinese medicines and widely applied in clinical practice. Currently, many researchers have proved the rationality of the therapy based on the traditional Chinese medicine mechanism and on the data from clinical practice, but its action mechanism is uncertain at present. In this study, with the assistance of pediatric practitioners, the automated ribosomal intergenic-spacer analysis (ARISA) was adopted to study the effect of the adjuvant therapy with Dingguier umbilical paste on intestinal flora of diarrhea infants, in which Dingguier umbilical paste served as the adjuvant therapy in oral traditional Chinese medicines and fecal samples of infants with different diarrhea symptoms were collected and used as the study materials. The results showed that the adjuvant therapy had a significant effect on the shift of intestinal flora, which was associated with the decrease in the similarity difference to the normal control group and the increase in the number of operational taxonomic units (OTUs) shared with the normal control group. Additionally, adjuvant therapy with Dingguier umbilical paste also showed long action duration and increased OTUs number. These results indicated that Dingguier umbilical paste has the effect in restoring the micro-ecosystem of unbalanced intestinal bacteria. Intestinal flora may be one of major targets for the applicator therapy for the infant diarrhea, but not for the single oral traditional Chinese medicine for infant diarrhea.

Wet-plate culture studies of Penicillium sp. PT95 and Q1 for mass production of sclerotia.

Penicillium sp. PT95 and Q1 strains were able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. To determine the potential availability of the wet-plate method for mass production of sclerotia, nine kinds of liquid media were used culture the PT95 and Q1 strains. The results of the wet-plate culture showed that on 25% glycerol nitrate broth medium, the growth of both strains was relatively slow, and no sclerotia were found. Q1 strain cultured on Czapek's yeast extract broth medium could not form sclerotia. On other media, both strains could form sclerotia. For PT95 strain, the highest sclerotial biomass (380 mg plate(-1) ) and carotenoids yield (20.88 µg plate(-1) ) could be obtained on Czapek's yeast extract broth and Georgiou's liquid medium, respectively. For Q1 strain, malt extract broth medium gave the highest sclerotial biomass (340 mg plate(-1) ) and omitting iron Joham's liquid medium gave the highest carotenoids yield (18.29 µg plate(-1) ). The results from this study suggest the potential usage of wet-plate method in the mass production of sclerotia of the PT95 and Q1 strains.

Effect of copper-induced oxidative stress on sclerotial differentiation and antioxidants contents of Penicillium thomii Q1.

Penicillium thomii Q1 strain was able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. The aim of this work was to determine the effects of copper-induced oxidative stress on the sclerotial differentiation, biosynthesis of some endogenous antioxidants, and the activities of some antioxidative enzymes of Q1 strain. The results showed that the oxidative stress induced by copper was clearly dependent on the CuSO4 concentrations in media, and characterized by the initiation of lipid peroxidation. Under the copper-induced oxidative stress conditions, the time of exudates initiation, sclerotial initiation and sclerotial maturation of Q1 strain were advanced in 1-2 days. The analytical results of sclerotial biomass, carotenoids, and ascorbate contents showed that copper-induced oxidative stress favored the sclerotial differentiation and biosynthesis of carotenoids and ascorbate. The oxidative stress induced by a lower amount of CuSO4 in media could enhance significantly the superoxide dismutase and catalase activities of Q1 strain.

Soluble expression and purification of Brucella cell surface protein (BCSP31) of Brucella melitensis and preparation of anti-BCSP31 monoclonal antibodies.

Brucella cell surface protein (BCSP31) is potentially useful for diagnosing brucellosis. We aimed to establish a monoclonal antibody (MAb) against Brucella melitensis BCSP31 and to investigate its distribution in diagnosis. Soluble recombinant BCSP31 was successfully expressed and purified. Two MAbs (1F1 and 1E5) against B. melitensis BCSP31, effective in detecting both recombinant and cellular proteins, were obtained and characterized. The MAbs did not react with Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Mycobacterium tuberculosis, or Bacillus aeruginosus, but strongly reacted with BCSP31 and B. melitensis by ELISA and Western blot analysis. We also tested different Brucella species and brucellosis using the prepared anti-BCSP31 MAbs. BCSP31 and anti-BCSP31 MAbs may play important roles in future research in diagnosing brucellosis.