Novel Streptococcus uberis sequence types causing bovine subclinical mastitis in Hainan, China.

AIM: To determine the molecular epidemiology, genotypes and phenotypes of the major species of Streptococcus associated with bovine subclinical mastitis in Hainan, China. METHODS AND RESULTS: In total, 150 subclinical mastitis milk samples were collected from two large dairy farms in Hainan. On the basis of biochemical tests and 16S rDNA sequencing, 39 samples were Streptococcus positive and the most frequently isolated species was Streptococcus uberis (n = 29, 74.4%). According to multilocus sequence typing (MLST), and assays of biofilm formation, antimicrobial susceptibility, resistance and virulence genes, the S. uberis isolates were clustered into nine new sequence types (STs; ST986-ST994) but were not merged into a clonal group (except for ST991 [CC143]). All isolates produced biofilm, but most weakly. The dominant virulence pattern was hasABC + sua + gapC + oppF + pauA + mtuA + cfu (27/29, 91.1%), based on the 11 virulence genes tested. The majority of isolates (88.46%) carried at least one resistance gene, and more than half (58.62%) were multidrug-resistant. The main resistance genes were linB (65.5%), ermB (37.9%) and tetS (34.5%), among the six antibiotic resistance genes and 11 antimicrobials tested. CONCLUSION: Environmental S. uberis is important in bovine subclinical mastitis in Hainan. SIGNIFICANCE AND IMPACT OF THE STUDY: Streptococcus uberis isolates in Hainan, China, show distinct MLST, virulence and antibiotic resistance characteristics.

Autophagy activated by Toxoplasma gondii infection in turn facilitates Toxoplasma gondii proliferation.

Autophagy was found to play an antimicrobial or antiparasitic role in the activation of host cells to defend against intracellular pathogens, at the same time, pathogens could compete with host cell and take advantage of autophagy to provide access for its proliferation, but there are few articles for studying the outcome of this competition between host cell and pathogens. Therefore, the aim of our study was to investigate the relationship between autophagy activated by Toxoplasma gondii (T. gondii) and proliferation of T. gondii affected by autophagy in vitro. Firstly, human embryonic fibroblasts (HEF) cells were infected with T. gondii for different times. The monodansylcadaverine (MDC) staining, acridine orange (AO) staining, punctuate GFP-LC3 distribution, and transmission electron microscopy (TEM) assays were conducted, and the results were consistent in showing that gondii infection could induce autophagy. Secondly, HEF cells were infected with T. gondii and treated with autophagy inhibitor bafilomycin A1 or inducer lithium chloride for different times. Giemsa staining was conducted, and the results exhibited that T. gondii infection-induced autophagy could in turn promote T. gondii proliferation. Simultaneously, the results of Giemsa staining also revealed that autophagy inhibitor could reduce the number of each cell infected with T. gondii and inhibit T. gondii proliferation. In contrast, autophagy inducer could increase the number of each cell infected with T. gondii and encourage T. gondii proliferation. Therefore, our study suggests that T. gondii infection could activate autophagy, and this autophagy could in turn facilitate T. gondii proliferation in HEF cells for limiting nutrients.

An outbreak of Providencia rettgeri bacteremia at a Ptyas mucosus farm in Hainan, China.

Aim: To describe the histopathology and etiology of an outbreak of respiratory disease at a Ptyas mucosus farm in Hainan, China. Methods and results: The etiology was confirmed by gross examination and microscopic analysis. The bacterial isolates from blood and internal organs were identified by biochemical analysis and 16S rRNA gene sequencing. The virulence and antibiotic resistance characteristics of the isolates were further demonstrated by polymerase chain reaction (PCR), disk diffusion testing, and LD50 analysis in Kunming mice. Histopathological analysis of the diseased P. mucosus revealed systemic lesions, including severe airway obstruction with large numbers of inflammatory cells and cellulose exudates in the lungs; severe multifocal hepatocyte vacuolar degeneration and necrosis in the liver with excessive inflammatory exudates and chronic granuloma; splenic hemorrhage and partial loss of splenic structure; and renal vascular and interstitial congestion. Providencia rettgeri was isolated from the blood and multiple internal organs (liver, spleen, kidneys, and lungs). All examined isolates (H1, H4, and H13) were multidrug-resistant but sensitive to four antibiotics-cefepime, imipenem, chloramphenicol, and ciprofloxacin. Both H1 and H4 carried five resistance genes [bla OXA, tet(A), tet(B), tet(E), and aac (3)-IIa], whereas H13 only carried the tet(A) gene. The dominant virulence pattern of the three isolates was hlyA + ZapA + luxS + rsbA. The virulence of H1 strain was tested, and its 50% lethal dose (LD50) in mice was 2.29 × 108 CFU ml-1. Conclusion: To our knowledge, this is the first study to describe an outbreak of bacteremia caused by P. rettgeri in farmed rat snakes. Significance and impact of the study: The results highlight that P. rettgeri is an emerging bacterial pathogen in farmed reptiles.

[The relationship among congenital Toxoplasma gondii infection, pregnancy outcome and T lymphocyte subsets in umbilical cord blood].

OBJECTIVE: To reveal the relationship among congenital Toxoplasma gondii (T. gondii) infection, T lymphocyte cell subsets in umbilical cord blood and pregnancy outcome. METHODS: 784 umbilical cord blood samples were collected and information of pregnancy outcomes was collected in a hospital of Hefei city, Anhui province during March 2009 to May 2010. T. gondii IgM antibodies in the sera were detected by ELISA. For all neonates infected with T. gondii and 10 healthy neonates, T lymphocyte cell subsets were detected by flow cytometry. RESULTS: According to the detection results of T. gondii IgM antibodies, 784 neonates were divided into infection group (21 neonates) and control group (763 neonates). The body weight and 1 min Apgar score of infection group were (3116.4 ± 352.6) g and (8.21 ± 1.26) points, respectively, which were statistically lower than control group ((3220.1 ± 242.3) g and (8.77 ± 1.61) points, respectively) (P < 0.01). The proportion of adverse pregnancy outcome of infection group was 19.0% (4/21), which was statistically greater than control group (4.8%, 37/763) (P < 0.01). The percentage of CD(3)(+) T lymphocyte cells in umbilical cord blood in infection group with and without adverse pregnancy outcomes were (64.51 ± 5.27)% and (64.32 ± 4.56)%, respectively, which were statistically lower than control group ((69.32 ± 4.32)%) (P < 0.01). The ratio value of CD(4)(+)/CD(8)(+) in infection group with, without adverse pregnancy outcomes and control group are 1.39 ± 0.24, 1.64 ± 0.28 and 2.34 ± 0.46, respectively, which showed statistical difference between any 2 groups (P < 0.01). CONCLUSION: T. gondii infection leads to adverse pregnancy outcomes and disorder of cellular immunity while T lymphocyte cell subsets are closely associated with adverse pregnancy outcome.

Interferon-λ1 suppresses invasion and enhances autophagy in human osteosarcoma cell.

OBJECTIVE: The purpose of the present study was to determine whether type III IFN can modulate the autophagic response in human osteosarcoma cell. METHODS: Human osteosarcoma cell were treated with Interferon-λ1. We investigated that Interferon-λ1 could inhibit the invasive ability of osteosarcoma cells by Matrigel invasion assay. Autophagy were assessed by acridine orange staining, MDC staining and Transmission electron microscopy. RESULTS: In this study, we found that Interferon-λ1 could inhibit the invasive ability of osteosarcoma cells. Acridine orange staining and MDC staining showed that Interferon-λ1 triggered the accumulation of acidic vesicular and autolysosomes in osteosarcoma cell. The acridine orange osteosarcoma cell ratios were 3.6 ± 0.5%, 4.5 ± 0.8%, and 12.4 ± 1.7% after treatment with 1, 10, and 100 ng/mL Interferon-λ1 for 48 h. Osteosarcoma cell cells treated with 100 ng/mL Interferon-λ1 for 48 h developed autophagy some-like characteristics, including single or double-membrane vacuoles containing intact and degraded cellular debris. CONCLUSIONS: Interferon-λ1 could inhibit the invasive ability of osteosarcoma cells. Autophagy can be induced in a dose-dependent manner by treatment with Interferon-λ1 in osteosarcoma cell.