Incidence of white muscle disease, a viral like disease associated with mortalities in hatchery-reared postlarvae of the giant freshwater prawn Macrobrachium rosenbergii (De Man) from the south-east coast of India

Incidence of post‐larval mortalities of 30–100% was reported from commercial freshwater prawn, Macrobrachium rosenbergii (De Man) hatcheries in Andhra Pradesh and Tamil Nadu (south‐eastern states of India) since 2001. Infected postlarvae (PL) exhibited clinical symptoms with lethargy, anorexia and whitening of abdominal muscles and the disease was identified as white muscle disease (WMD). The waterborne infection of WMD was induced in the laboratory by exposing uninfected and healthy M. rosenbergii PL to the filtered muscle homogenates of the naturally infected PL, resulting in mortality that reached 99% within 10 days post infection. Histopathological examination of the infected animals revealed highly necrotic musculature. Degenerated muscle areas showed aggregations of melanized nuclei, many of which looked like inclusion bodies. Bacteriological examination of affected PL showed the presence of Staphylococcus spp. as a predominant organism, while laboratory challenge of healthy PL with this bacterial isolate did not reproduce WMD.     

人工感染葡萄球菌后鸡血液指标检测

8周龄健康肉鸡60只随机分成2组,试验组(45只)经关节腔注射鸡源致病性金黄色葡萄球菌2.5×109cfu,复制鸡葡萄球菌性关节炎的病理模型,对照组(15只)经关节腔注射PBS。对所建立的病理模型进行临床症状观察、外周血内细菌、白细胞及其分类计数以及抗体水平的动态研究。结果显示:试验组接种后均发展为典型的关节炎症状。整个试验期内试验组的死亡率为51.11％,对照组表现正常。接种后1-5 d外周血内金黄色葡萄球菌迅速升高。试验组鸡接种后血液中白细胞(WBC)总数升高。试验组和对照组的WBC总数的差异水平在第1、5、7、21、28 d极显著(P<0.01)。异嗜性细胞和淋巴细胞总数在接种后1周内明显升高,与对照组相比差异水平极显著(P<0.01);单核细胞在第3 d上升至11.67％,显著高于对照组。淋巴细胞的转化率在接种后第3、5、7 d的转化率极显著的高于对照组(P<0.01),第7 d达到峰值70.30％。试验组的抗体水平在整个试验期内呈缓慢增长趋势。     

苹果多酚抑菌作用的研究

为建立多酚浓度与细菌生长速率之间的关系,该文采用微量量热法研究了不同浓度的苹果多酚对金黄色葡萄球菌和大肠杆菌的抑制作用。结果表明,苹果多酚对金黄色葡萄球菌和大肠杆菌均具有一定程度的抑制作用,且多酚浓度与细菌生长速率常数之间存在线性关系,其抑制金黄色葡萄球菌和大肠杆菌的临界生长用药浓度分别为0.218 6和1.558 0 mg/mL。      

不同营养液配方对花鱼共养体系的影响

[目的]为花鱼共养提供指导性意见.[方法]以绿萝茎段和锦鲤为试验材料,探讨不同营养液配方对绿萝和锦鲤组成的花鱼共养体系的影响.[结果]在绿萝根长增量方面,华南农业大学叶菜类3/4配方根长增量最大,日本园式配方母液3/4配方根长增量最小.华南农业大学叶菜类3/4配方绿萝叶绿素含量高于其他配方,日本因式配方母液1/4配方叶绿素含量最低.华南农业大学叶菜类1/4配方绿萝鲜重增量最大,日本因式配方母液4/4配方鲜重增量最小.华南农业大学叶菜类1/4配方绿萝叶数增量多于其他配方,日本园式配方母液3/4配方叶数增量最少.华南农业大学叶菜类1/4配方锦鲤存活时间最长,日本园式配方母液2/4配方锦鲤存活时间最短.[结论]对花鱼共养体系而言,华南农业大学叶菜类配方1/4剂量为最佳配方.     

奶牛乳房炎源性金黄色葡萄球菌分离株N_2的耐药性分析及其基因特征

以乳房炎源性金黄色葡萄球菌分离株N2为研究对象,采用纸片扩散法分析了耐药性,应用刚果红法检测了生物被膜形成能力,利用PCR法扩增了8种生物被膜形成基因和9种肠毒素基因。结果表明,金黄色葡萄球菌分离株N2具有广泛的耐药性,仅对苯唑西林高度敏感,具有较强的生物被膜形成能力,携带除bap外所有的被测生物被膜相关基因和sea、sec、seg、sei 4种肠毒素基因。结果表示金黄色葡萄球菌分离株N2可能存在多种侵袭方式,在临床上难以防治,为进一步以该菌株为研究材料进行相关研究奠定了基础。     

Immune response of heifers against a Staphylococcus aureus CP5 whole cell and lysate vaccine formulated with ISCOM Matrix adjuvant

Staphylococcus aureus is the most frequently isolated pathogen from bovine intramammary infections worldwide. Commercially available vaccines for mastitis control are composed either of S. aureus lysates or whole-cells formulated with traditional adjuvants. We recently showed the ability of a S. aureus CP5 whole-cell vaccine adjuvanted with ISCOM Matrix to increase specific antibodies production in blood and milk, improving opsonic capacity, compared with the same vaccine formulated with Al(OH)₃. However, there is no information about the use of ISCOM Matrix for the formulation of bacterial lysates. The aim of this study was to characterize the innate and humoral immune responses induced by a S. aureus CP5 whole-cell or lysate vaccine, formulated with ISCOM Matrix after immunization of pregnant heifers. Both immunogens stimulated strong humoral immune responses in blood and milk, raising antibodies that increased opsonic capacity. Lysate formulation generated a higher and longer lasting antibody titer and stimulated a higher expression of regulatory and pro-inflammatory cytokines compared with the whole-cell vaccine.     

食品中金黄色葡萄球菌的PCR检测

建立一种快速聚合酶链反应(PCR)方法,用于食品中金黄色葡萄球菌的检测.针对金黄色葡萄球菌独有的SEA基因设计1对引物,在PCR体系中对相应片断进行扩增,最后通过电泳技术与阳性对照进行对比来判断阴阳性.结果表明,该方法检出率高,样品中模板DNA含量仅有0.05 pg即可检出金黄色葡萄球菌,24 h即可报告结果.因此,PCR方法是一种高效、敏感、特异性高的检测技术,可用于食品中金黄色葡萄球菌的快速检测.     

产PVL金黄色葡萄球菌对奶牛乳腺上皮细胞内质网应激和自噬的影响

【目的】研究产PV-杀白细胞素（Panton Valentine leukocidin,PVL）金黄色葡萄球菌ATCC49775（产PVL标准菌株）、ΔPVL 49775（PVL基因缺失株）以及体外重组PVL（rPVL）对奶牛乳腺上皮细胞（bovine mammary epithelial cells,BMECs）内质网应激和自噬的影响,为系统阐述金黄色葡萄球菌及PVL对BMECs损伤的分子机制奠定基础。【方法】用感染复数（MOI）为30的金黄色葡萄球菌菌株ATCC49775和ΔPVL 49775感染BMECs,于感染后3和6 h取样;用100 ng/mL rPVL处理BMECs,于处理后1,3和6 h取样;以未处理的BMECs为对照（CK）。用免疫荧光法检测样品BMECs细胞的自噬体荧光强度;提取样品细胞的总蛋白,以GADPH为内参蛋白,采用Western blot法检测各处理组内质网应激相关蛋白（CHOP和GRP78）和自噬相关蛋白（LC3 Ⅱ、ATG5、Beclin1和p62）的相对表达量。【结果】ATCC49775、ΔPVL 49775感染后不同时间,BMECs自噬体荧光强度均极显著（P＜0.01）高于CK,内质网应激相关蛋白（CHOP和GRP78）和自噬相关蛋白（LC3-Ⅱ、ATG5、Beclin1和p62）的表达水平也大多显著(P<0.05)或极显著（P＜0.01）高于CK;同一处理时间下, ATCC49775感染组自噬体荧光强度和相关蛋白表达水平均显著(P<0.05)或极显著（P＜0.01）高于ΔPVL49775感染组。 rPVL处理后不同时间,BMECs的自噬体荧光强度均极显著（P＜0.01）高于CK,内质网应激和自噬相关蛋白的表达水平大多极显著（P＜0.01）高于CK。【结论】产PVL金黄色葡萄球菌ATCC49775、ΔPVL 49775以及rPVL均加剧了BMECs的内质网应激和自噬,说明PVL在金黄色葡萄球菌感染BMECs的过程中有重要作用。     

Bactericidal kinetics of marine-derived napyradiomycins against contemporary methicillin-resistant Staphylococcus aureus

There is an urgent need for new antibiotics to treat hospital- and community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections. Previous work has indicated that both terrestrial and marine-derived members of the napyradiomycin class possess potential anti-staphylococcal activities. These compounds are unique meroterpenoids with unusual levels of halogenation. In this paper we report the evaluation of two previously described napyradiomycin derivatives, A80915A (1) and A80915B (2) produced by the marine-derived actinomycete, Streptomyces sp. strain CNQ-525, for their specific activities against contemporary and clinically relevant MRSA. Reported are studies of the in vitro kinetics of these chemical scaffolds in time-kill MRSA assays. Both napyradiomycin derivatives demonstrate potent and rapid bactericidal activity against contemporary MRSA strains. These data may help guide future development and design of analogs of the napyradiomycins that could potentially serve as useful anti-MRSA therapeutics.     

Feline pyoderma therapy

Feline pyoderma is a disease entity more prevalent than previously described. Diagnosis is made by finding bacteria in the presence of inflammatory cells or bacterial phagocytosis on routine cytological examination. Diseases leading to secondary bacterial pyoderma include allergic and inflammatory skin diseases, parasitosis, feline chin acne, and others. Lesions of feline pyoderma are variable and include crusted and eroded papules, pustules, furuncles, eroded to ulcerated plaques with variable exudation and crusting, and linear to nodular ulcerative granulomatous lesions. Three cases of feline pyoderma responsive to antimicrobial therapy are discussed: case 1, a 10.5-year-old male neutered domestic short hair with eosinophilic lip ulcer, case 2, a 7-year-old male neutered domestic short hair with multiple cutaneous eosinophilic plaques, and case 3, an 8-month-old male neutered domestic short hair cat with Pseudomonas dermatitis, vasculitis, and panniculitis. Antibiotic selection for treatment of feline pyoderma should be based on cytological examination, and culture and sensitivity in unresponsive cases.