透明颤菌血红蛋白基因在多粘芽孢杆菌中的克隆和表达

本研究将启动子P43与透明颤菌血红蛋白(Vitreoscilla hemoglobin)基因(vgb)通过重叠PCR进行融合,克隆到芽孢杆菌表达载体p CM20上,将筛选得到的重组载体p CM20-vgb转化多粘芽孢杆菌(Paenibacillus polymyxa)NR1,Western-Blot表明重组菌株表达了VHb蛋白,该蛋白的表达对重组菌体的生长和多粘菌素的产生均有促进作用。     

多粘芽孢杆菌中2,3-丁二醇脱氢酶的克隆和表达

将来自于多粘芽孢杆菌(Paenibacillus polymyxa)中的2,3-丁二醇脱氢酶基因pla C在大肠杆菌(Escherichia coli)BL21中进行了诱导表达,并对其酶学性质进行研究。结果表明,该基因的表达产物主要是生成内消旋型2,3-丁二醇,其氧化2,3-丁二醇的最适温度是50℃,最适pH为10,而还原乙偶姻的最适温度为60℃,最适pH为6。     

治疗多重耐药革兰氏阴性菌感染的有效抗菌药——多黏菌素

综述了多黏菌素的理化性质、抗菌活性、药动学、药效学、临床应用、残留等方面的特点和研究概况,以期为该药在兽医临床上的应用提供依据。     

Anaphylaxis to Ophthalmic Medication in a Cat

There is an increasing incidence of anaphylactic reactions in cats due to the administration of ophthalmic bacitracin, neomycin, polymyxin medications. Most of the reported cases have been fatal. This is the report of a cat that survived the initial episode only to develop renal failure and cardiomyopathy. This lead to euthanasia seven days later. Dr. Kathryn Meyer of the U.S. Pharmacopeia and Dr. Signe Plunkett of the Emergency Animal Clinic in Phoenix are conducting an ongoing study, and they are interested in the reports of any additional cases.     

Punctal stenosis in 6 dogs following the long‐term use of topical neomycin‐polymyxin B‐dexamethasone

Six dogs were diagnosed with punctal stenosis following the long‐term use of topical neomycin‐polymyxin B‐dexamethasone (NPD). All patients were initially presented for ophthalmic diseases requiring ongoing anti‐inflammatory therapy. Five of the 6 dogs had previously or concurrently been treated with topical anti‐inflammatory medications other than NPD. One patient exclusively received topical NPD prior to the diagnosis of punctal stenosis. The onset of punctal stenosis following therapy with NPD was variable among patients, ranging from 4 months to over 1 year. Diagnosis of punctal stenosis was made based upon the presence of epiphora and visualization of fibrotic tissue over the nasolacrimal puncta.     

Improving clinical outcomes via responsible antimicrobial use in horses

The growing problem of antimicrobial resistance affects veterinarians on a daily basis. Antimicrobial stewardship and responsible prescribing are essential for a future with effective antimicrobials, as it is unlikely that new antimicrobials will become available for use in horses in the near future. Extended-spectrum β-lactamase (ESBL) producing Enterobacteriaceae, methicillin-resistant Staphylococcus aureus (MRSA) and Salmonella spp. are pathogens of significant concern but there are also other opportunistic pathogens such as Pseudomonas spp., α-haemolytic Streptococcus spp., Enterococcus spp. and Acinetobacter spp. which, due to their high intrinsic resistance, have limited treatment options in adult horses. It is essential that highest priority critically important antimicrobials such as ceftiofur, enrofloxacin, rifampicin and polymyxin B are used prudently in horses and ideally based on culture and antimicrobial susceptibility testing (AST). For example, the use of polymyxin B at a low anti-endotoxic dose rather than at a higher antimicrobial dose in horses for the treatment of systemic inflammatory response syndrome is a potential driver for resistance to colistin (polymyxin E), an antimicrobial used as a last resort in the treatment of multidrug resistant (MDR) Enterobacteriaceae infections in humans. Serum procalcitonin levels are used in humans to distinguish noninfectious inflammatory conditions from inflammation caused by bacteria and other infectious agents and are also used to guide cessation of antimicrobial treatment. Although no such studies have been performed in horses, this or other markers may prove to be helpful in guiding antimicrobial treatment decisions in the future. Optimising sampling techniques and good communication with the microbiology laboratory are essential for generating the accurate culture and AST results that underpin appropriate antimicrobial use. Additionally, there is clearly a need for national and international harmonisation of laboratory methods in order to improve the reliability and consistency of results reported by different laboratories.     

碳源对多粘类芽孢杆菌生长和多粘菌素E合成的影响

为探究提高多粘菌素E产量的方法,在发酵培养基中分别添加葡萄糖、蔗糖、麦芽糖、乳糖和可溶性淀粉,应用平板菌落计数和HPLC法研究了其对多粘类芽孢杆菌生长和多粘菌素E产量的影响。结果表明,5种碳源对多粘类芽孢杆菌的生长和多粘菌素E产量的影响不同,可溶性淀粉是菌体生长的最适碳源,且多粘菌素E产量依次为可溶性淀粉>乳糖>蔗糖>麦芽糖>葡萄糖。可溶性淀粉有助于延长多粘菌素E的产素期和提高其合成速率,与葡萄糖作碳源相比,多粘菌素E的产量和合成速率分别提高了111%和60%。因此,可溶性淀粉是多粘菌素E合成的最适碳源。