Ovariohysterectomy of three vampire bats (Desmodus rotundus)

Three sexually mature female common vampire bats (Desmodus rotundus) housed at the North Carolina Zoological Park, Asheboro, North Carolina, were selected for surgical ovariohysterectomy. All animals were induced and maintained with isoflurane anesthetic gas. Magnification loop glasses were worn by the surgeon for the procedure. A ventral midline incision was made into the abdominal cavity. Simple micro-ophthalmic surgical packs along with hemoclips were used to perform the ovariohysterectomies. The linea alba and muscular layers were closed using a simple continuous suture pattern with 4-0 polydioxanone suture. The skin was apposed using a horizontal mattress suture pattern with 4-0 polydioxanone suture. Animals recovered with minimal deleterious side effects. Animals were housed together in a recovery chamber and administered meloxicam at 0.2 mg/kg placed in their blood meal once daily for 7 days postoperatively, after which they were returned to their normal enclosures.     

A plaque-purified rabies virus (strains V-319) derived from a vampire bat (Desmodus rotundus) in Mexico: vaccine potential

A plaque-purified experimental rabies vaccine was developed from an isolate (strain V-319) made from a naturally infected vampire bat (Desmodus rotundus). Two different vaccines were prepared; one was live virus and the second was an inactivated rabies virus preparation. The live virus vaccine, as well as a betapropiolactone-inactivated vaccine, gave complete protection to challenge inoculation after 1 year. In contrast, greater than 80% of the non-vaccinated experimental control cattle died of rabies. The live virus vaccine could be given at doses as low as 10(5) PFU without loss of efficacy. It did not cause adverse reactions. More than 10,000 cattle have been vaccinated with the live virus vaccine under field conditions. No rabies deaths occurred in vaccinated cattle during a 2-year postvaccinal period. The serological responses of vaccinated cattle indicated protection that endured at least 1 year.     

Aeromonas hydrophila as cause of hemorrhagic septicemia in a ground-hornbill (Bucorvus abyssinicus)

An acute hemorrhagic septicemia in a captive ground-hornbill (Bucorvus abyssinicus) is reported. Aeromonas hydrophila was isolated from lungs, liver, kidney, and intestines. Postmortem lesions were characterized by hemorrhages in the internal organs. Microscopically, necrotic lesions were found in the liver, lungs, and kidney. Factors that might have contributed to the clinical disease condition are discussed.     

Extended‐spectrum beta‐lactamase‐producing Escherichia coli in common vampire bats Desmodus rotundus and livestock in Peru

Antibiotic resistance mediated by bacterial production of extended‐spectrum beta‐lactamase (ESBL) is a global threat to public health. ESBL resistance is most commonly hospital‐acquired; however, infections acquired outside of hospital settings have raised concerns over the role of livestock and wildlife in the zoonotic spread of ESBL‐producing bacteria. Only limited data are available on the circulation of ESBL‐producing bacteria in animals. Here, we report ESBL‐producing Escherichia coli in wild common vampire bats Desmodus rotundus and livestock near Lima, Peru. Molecular analyses revealed that most of this resistance resulted from the expression of bla_CTX‐M‐15 genes carried by plasmids, which are disseminating worldwide in hospital settings and have also been observed in healthy children of Peru. Multilocus sequence typing showed a diverse pool of E. coli strains carrying this resistance that were not always host species‐specific, suggesting sharing of strains between species or infection from a common source. This study shows widespread ESBL resistance in wild and domestic animals, supporting animal communities as a potential source of resistance. Future work is needed to elucidate the role of bats in the dissemination of antibiotic‐resistant strains of public health importance and to understand the origin of the observed resistance.     

Class 1 integrons in Aeromonas hydrophila isolates from farmed Nile tilapia (Oreochromis nilotica)

The aim of this study was to determine antimicrobial resistance of Aeromonas hydrophila isolated from farmed Nile Tilapia. A total of 50 A. hydrophila isolates from clinical cases were screened for the presence of class 1, 2 and 3 integrons and all the strains resistant to enrofloxacin and/or ciprofloxacin (n=19) examined for mutation in the quinolone resistance-determining regions (QRDRs) of gyrA and parC. The intI1 gene was detected in 23 A. hydrophila strains (46%) but no intl2 and intl3 were detected. Among these, 14 isolates (60.8%) carried gene cassettes inserted in variable regions i.e., partial aadA2, aadA2, dfrA1-orfC and dfrA12-aadA2, of which the most common gene cassette array was dfrA12-aadA2 (26.09%). Conjugal transfer of class 1 integrons with resistance gene array was detected. All the A. hydrophila strains resistant to enrofloxacin and/or ciprofloxacin possessed mutations in the QRDRs of gyrA and parC. Only a Ser-83-Ile substitution was identified in GyrA and only a Ser-80-Ile amino change was found in ParC. The data confirms that A. hydrophila from farm-raised Nile Telapia serve as a reservoir for antimicrobial resistance determinants.     

Pharmacokinetic/pharmacodynamic relationship of marbofloxacin against Aeromonas hydrophila in Chinese soft‐shelled turtles (Trionyx sinensis)

The single‐dose disposition kinetics of the antibiotic marbofloxacin were determined in Chinese soft‐shelled turtles (n = 10) after oral and intramuscular (i.m.) dose of 10 mg/kg bodyweight. The in vitro and ex vivo activities of marbofloxacin in serum against a pathogenic strain of Aeromonas hydrophila were determined. A concentration‐dependent antimicrobial activity of marbofloxacin was confirmed for levels lower than 4 × MIC. For in vivo PK data, values of AUC: minimum inhibitory concentration (MIC) ratio for serum were 1166.6 and 782.4 h, respectively, after i.m. and oral dosing of marbofloxacin against a pathogenic strain of A. hydrophila (MIC = 0.05 μg/mL). The ex vivo growth inhibition data after oral dosing were fitted to the inhibitory sigmoid Emax equation to provide the values of AUC/MIC required to produce bacteriostasis, bactericidal activity and elimination of bacteria. The respective values were 23.79, 36.35 and 126.46 h. It is proposed that these findings might be used with MIC₅₀ or MIC₉₀ data to provide a rational approach to the design of dosage schedules, which optimize efficacy in respect of bacteriological as well as clinical cures.     

嗜水气单胞菌J-1株外膜蛋白Omp38的抗原性分析

根据GenBank已发表的嗜水气单胞菌(Aeromonas hydrophila)外膜蛋白Omp38的基因序列设计引物,以Ah J-1株基因组为模板,扩增omp38基因片段,定向克隆至表达质粒pET32 a中,将重组原核表达质粒pET32 a-omp38转化至大肠杆菌BL21,诱导表达出分子量约35 ku的重组蛋白。用纯化的重组蛋白免疫新西兰兔制备抗血清,ELISA检测抗体效价为1∶25 600,表明该蛋白有良好的免疫原性。PCR检测表明,omp38基因可在73%(22/30)的嗜水气单胞菌中发现。重组蛋白抗血清与30株嗜水气单胞菌分离株进行凝集试验,所有分离株均可在不同程度上发生反应,表明该重组蛋白是一种潜在的共同保护性抗原,可作为基因工程亚单位疫苗的候选成分。     

Carp erythrodermatitis (CE) due to an Aeromonas hydrophila infection. Casuistic and experimental results

In November 1987 high losses of carp (Cyprinus carpio) with the main symptom of skin ulcera were observed in a farm in northern Greece. Sixty-six isolates of bacteria, characterized mainly as Aeromonas hydrophila or Pseudomonas spp. could be isolated from lesions of diseased fish. Transmission experiments with these isolates using mirror carp showed that Aeromonas hydrophila strains induced identical clinical and pathological pictures after intra- or subcutaneous injection. Extracts of these Aeromonas hydrophila isolates, as well as a supernatant of culture bouillon were toxic for carp and mice, indicating the presence of endo- and exotoxins. The results prove that carp erythrodermatitis (CE) may be caused by different bacteria, mainly including A. hydrophila.     

嗜水气单胞菌对黑斑蛙和花背蟾蜍的致病性研究

利用经分类鉴定并保存于固定培养基中的ＡＨ９８０４嗜水气单胞菌株对黑斑蛙和花背蟾蜍进行动物接种感染试验（腹腔接种剂量２ｍＬ、含菌数１４４×１０８个）,结果显示,该菌对上述２种动物具有明显的致病作用。同时,使用所制备高免血清作了同种动物免疫保护试验（血清抗体效价１２８０、肌肉接种剂量３０ｍＬ）,对其结果进行了验证。     

长春市售乌鳢携带嗜水气单胞菌情况调查

为探讨乌鳢体内嗜水气单胞菌携带情况,本调查以长春市售表观健康乌鳢为研究材料,从其体内分离并鉴定嗜水气单胞菌,并对分离株携带毒力基因情况进行调查,同时选取代表株进行致病性试验。结果显示:共分离嗜水气单胞菌107株,其中56%以上分离株携带3种以上毒力基因,88.79%(95/107)的分离株携带Lux S基因;致病性试验结果显示,携带毒力基因菌株对小鼠、斑马鱼均有一定致病性,随着菌株携带毒力基因种类的增多,致病力也相应增强。研究结果对研发食用乌鳢的公共卫生安全具有一定意义。     

The impact of quorum sensing on the virulence of Aeromonas hydrophila and Aeromonas salmonicida towards burbot (Lota lota L.) larvae

In this study, the link between quorum sensing in Aeromonas spp. and its virulence towards burbot (Lota lota) was investigated. High mortality occurred in burbot juveniles challenged with Aeromonas salmonicida HN-00, but not in juveniles challenged with Aeromonas hydrophila AH-1N. Meanwhile, both A. hydrophila AH-1N and A. salmonicida HN-00 were virulent towards larvae. The effect of quorum sensing on the virulence of A. hydrophila AH-1N towards burbot larvae was further investigated using quorum sensing mutants (N-(butyryl)-L-homoserine lactone production and receptor mutants). Challenge with these mutants resulted in higher survival of burbot larvae when compared to challenge with the wild type, and the addition of the signal molecule N-butyryl-L-homoserine lactone restored the virulence of the quorum sensing production mutant. Moreover, quorum sensing inhibitors protected the burbot larvae from both Aeromonas strains. Finally, the freshwater micro-algae Chlorella saccharophila and Chlamydomonas reinhardtii, which are able to interfere with quorum sensing, also protected burbot from the pathogens. However, QS interference was unlikely to be the only mechanism. This study revealed that the virulence of Aeromonas spp. towards burbot is regulated by quorum sensing and that quorum sensing inhibitors and micro-algae are promising biocontrol agents.