工厂化生产杏鲍菇细菌性病害的防治

工厂化生产杏鲍菇细菌性病害,是由假单孢杆菌引发的重要病害,在特定的控温、控湿、控光、控CO2条件下,每年重复利用出菇房18次以上的出菇房很容易发生、并迅速传播,给杏鲍菇工厂化生产企业带来不同程度的损失;研究、制定的10条预防措施,可以有效控制病害的发生、蔓延。     

Prevalence of campylobacter in pigs during fattening; an epidemiological study

Summary

Numerous epidemiological reports implicate foods of animal origin as vehicles of human campylobacteriosis. Pigs are probably an important reservoir of campylobacter and a potential source of human infection. In order to improve our knowledge of the epidemiology of campylobacter in pigs, the prevalence of campylobacter and its contamination of feed were monitored in eight pig farms. Faeces samples of pigs aged 11 and 22 weeks, and samples of rectal, ileal and gastric content at a slaughterhouse were collected for bacteriological examination. On 5 farms, subsequent groups of pigs housed in the same stalls was sampled, too. A selection of the campylobacter isolates was characterized with a genetic typing method (RFLP). More than 85% of the sampled porkers were shown to be intestinal carriers of campylobacter at all stages of fattening. Subsequent groups of pigs housed in the same stalls were all carriers, too. The level of campylobacters in the faeces tended to decrease as the pigs got older. There was no difference in the frequency and level of infection with campylobacter between porkers on different farms. The feeding system (wet feed versus dry pellets) did not seem to influence the prevalence of campylobacter although wet feed gave lower counts of Enterobacteriaceae in the faeces.

RFLP‐typing showed a high diversity of campylobacter strains at each sampling on the farm. Similarities were seen between strains isolated during two subsequent samplings of the same group of pigs, but not between strains isolated on the same farm from subsequent groups of pigs housed in the same stall. This suggests that the piglets were already infected at a young age on the breeding farm.     

Replant diseases: Bacterial community structure and diversity in peach rhizosphere as determined by metabolic and genetic fingerprinting

Peach tree replant disease, though reported on in the literature for more than two centuries, has yet to have its causes clearly defined. Decline in peach productivity has been attributed to toxic agents, insects, nutritional disturbances, spray residues, fungi and nematodes. Bacteria has also been indicated as a contributing factor.Peach replant disease was reproduced by using two successive cultures on the same soil. Bacterial communities were isolated and characterized from healthy and diseased peach trees. The potential role of cyanide production by rhizobacteria in the replant problem of peaches was studied. Culture-dependent (evaluation of the number of culturable bacteria, metabolic activities, Biolog^® GN2) and independent (ribosomal intergenic spacer analysis, RISA) methods were used, in order to compare bacterial community structure and diversity in healthy and sick soils and to evaluate the possible role of cyanide.Bacterial densities were significantly increased in sick soils. Metabolic activities (Biolog^® GN2) and genetic structure, observed through RISA, were also significantly modified in sick soils. Changes in the composition of individual microbial groups in the rhizosphere of peach trees excavated from healthy or sick soil indicated the involvement of rhizobacteria in the etiology of the replant sickness of peach soil. More than 60% of the strains isolated from healthy soils corresponded to Pseudomonas sp. and 58% of the isolates from sick soils were Bacillus sp. This study determined that Bacillus were able to produce in vitro HCN. It also appeared that in sick soil, there was a shift in the structure of bacterial communities with an increase noted in phytotoxic microorganisms capable of producing HCN compounds.     

Bacteria and antibiotic resistance detection in fractures of wild birds from wildlife rehabilitation centres in Spain

Anatomic adaptations make birds more prone to open fractures with exposed bone parts losing vascularization. As a result of this exposure, fractures are colonized by different microorganisms, including different types of bacteria, both aerobic and anaerobic, causing osteomyelitis in many cases. For this reason, antibiotic treatment is common. However, carrying out antibiotic treatment without carrying out a previous antibiogram may contribute to increased resistance against antibiotics, especially in migratory wild birds. In this paper, bacterial counts regarding fracture type, bacterial identification and antibiotic resistance have been analysed in wild birds from wildlife rehabilitation centres in Spain. The results obtained showed that open fractures had higher bacterial counts (CFU/mL) than closed ones. Bacteria in family Enterobacteriaceae, identified were Escherichia spp., Enterobacter spp., Shigella spp., Hafnia alvei, Proteus mirabilis, Leclercia adecarboxylata and Pantoea agglomerans. Other bacteria present in wild birds’ fractures were Aeromonas spp., Enterococcus spp. Bacillus wiedmannii and Staphylococcus sciuri. All species found presented resistance to at least one of the antibiotics used. Wild birds can be implicated in the introduction, maintenance and global spreading of antibiotic resistant bacteria and represent an emerging public health concern. Results obtained in this paper support the idea that it is necessary to take this fact into account before antibiotic administration to wild animals, since it could increase the number of bacteria resistant to antibiotics.     

Studies on Bovine Leukosis

Summary

An enzyme linked immunosorbent assay (ELISA) and the agar gel immunodiffusion test with bovine leukosis virus glycoprotein as antigen (AGIDT‐BLV gp) were further used to test 633 bovine sera for antibodies to BL V. Both tests detected the same number of sera positive (149) or negative (464) for antibodies. Nine sera were negative in the ELISA but found to be weakly positive (2 sera) or bending the control line (7) in the AGIDT‐BLV gp. On the other hand 11 sera were scored negative in the AGIDT‐BLV gp but were weakly positive (9 sera), positive (1), and strongly positive (I) in the ELISA. Both tests are used routinely in this Institute as they complement each other, specially if sera with low antibody titers are under investigation. It is concluded that ELISA can fully replace radioimmunoassays in the serodiagnosis of enzootic bovine leukosis.     

Efficacy of Enrofloxacin in the Treatment of Canine Bacterial Pyoderma

Abstract— Bacterial pyoderma was diagnosed in 30 dogs which were subsequently treated with enrofloxacin administered orally at 2.5 mg.kg^-1 of body weight every 12 h, for 2 to 14 weeks. Dogs were re-examined at the conclusion of antibiotic treatment and 28 (93.3 per cent) were found to have an excellent response. Relapses were seen in 25 per cent of these dogs after follow up periods of 1 to 4 months. Minor side effects were seen in only 1 dog. On the basis of this study, enrofloxacin is an excellent antibiotic for the treatment of canine bacterial pyoderma but must be administered well beyond the manufacturer's maximum recommendation for duration of therapy. Résumé— Une pyodermite bactérienne a été diagnostiquée chez 30 chiens qui furent traités avec de l'enrofloxacine administrée par voie orale à la dose de 2.5 mg/Kg toutes les 12 heures, pour une durée allant de 2.5 à 14 semaines. Les chiens furent réexaminés à la fin de l'antibiothérapie et 28 d'entre eux (93.3%) présentaient une excellente réponse au traitement. Des rechutes furent observées chez 25% des chiens lors de suivis portant sur des périodes de 1 à 4 mois. Des effets secondaires mineurs furent observés chez l'un des chiens. Cette étude montre que l'enrofloxacine est un excellent antibiotique pour le traitement des pyodermites canines mais, qu'il doit être administré pendant des délais beaucoup plus longs que ceux qui sont indiqués par le fabricant. Zusammenfassung— 30 Hunde mit bakteríellen Pyodermien wurden zweieinhalb bis vierzehn Wochen lang oral mit Enrofloxacin behandelt (2 täglich 2.5 mg/kg KGW). Nach Abschluß der Behandlung wurden die Tiere erneut untersucht. Bei 28 Patienten (93.3%) wurden hervorragende Ergebnisse erzielt. Bei 25% kam as nach 1 bis 4 Monaten zu Rezidiven. Geringe Nebenwirkungen wurden nur in einem Fall beobachtet. Die vorliegende Untersuchung zeigt, daß Enrofloxacin ein hervorragendes Antibiotikum für die Behandlung von Pyodermien ist, aber wesentlich länger als vom Hersteller angegeben verabreicht werden muß. Resumen Treinta perros, a los cuales se había diagnosticado una epiderma bacteriana, fueron tratado con Enrofloxacina via oral a una dosis de 2,5 mg/kg de peso corporal cada 12 horas durante un período de tiempo que oscíló entre las 2,5 semanas y las 14 semanas. Los perros se examinaron clínicamente de nuevo cuando acabó el tratamiento antibiótico y se observó en 28 (93,3%) una respuesta excelente. En un 25% de estos perros se observaron recidivas en un período comprendido entre uno y cuatro meses. Efectos colaterales de poca importancia se observaron úicamente en un animal. Según estos resultados puede concluirse que la Enrofloxacina es un antibiótico excelente para el tratamiento de las piodermas bacterianas del perro, aunque debe administrarse durante un período de tiempo superior al que recomiendan los productores.     

有效碳数法研究及其在农药气相色谱分析中的应用

有机化合物结构与其所含有的有效碳数有一定的关系，本文给出了２０类结构化合物及其所含有有效碳数的关系，并对理论计算值和实测值进行了比较，结果十分接近，利用有效碳数法可以设计农药分析实验方案和无标样的情况下测定农药杂质含量。     

小檗碱对金黄色葡萄球菌生物被膜的抑制作用

本实验以中药提取物小檗碱为研究对象,探究其对金黄色葡萄球菌生物被膜形成的抑制作用。实验采用常量肉汤稀释法测定小檗碱对金黄色葡萄球菌的最小抑菌浓度(MIC);随后分别选取2 MIC、1 MIC、0.5 MIC浓度小檗碱,采用结晶紫染色法测定其对金黄色葡萄球菌生物被膜生长的抑制率,同时采用实时荧光定量PCR测定2 MIC、1 MIC、0.5 MIC小檗碱对金黄色葡萄球菌Nuc基因的表达情况。结果显示,小檗碱对金黄色葡萄球菌的最小抑菌浓度(MIC)为62.5μg/mL,2 MIC、1 MIC、0.5 MIC浓度小檗碱对金黄色葡萄球菌生物被膜的抑制率分别为77.14%、66.91%和55.55%,荧光定量PCR测得各组金葡菌Nuc基因的Ct值大小为Ct值(0.5 MIC)> Ct值(1.0 MIC)>Ct值(2 MIC),说明随着小檗碱浓度的增大,对金黄色葡萄球菌生物被膜的抑制作用增强,呈现明显的浓度依赖性。本研究为小檗碱对金黄色葡萄球菌感染的防治提供数据支持。     

Presence of Bacteria on the External Genitalia of Healthy Stallions and its Transmission to the Mare at the Time of Breeding by Live Cover

The current field study used thoroughbred stallions and mares from central Kentucky to investigate the occurrence of potentially pathogenic bacteria on the stallion's external genitalia, based on cultures, and investigated the occurrence of bacteria and type of isolate in the mare's uterus after breeding by live cover to stallions with or without positive bacterial cultures. Fifteen thoroughbred stallions and 206 mares from two central Kentucky thoroughbred farms were used during the 2010 and 2011 breeding seasons. Samples for bacteriological evaluation were taken from the prepuce and postejaculate urethra (n = 201) of stallions. Uterine swabs (n = 264) were collected 12-18 hours postbreeding. For statistical analyses, a chi-squared test was used to test the relationship between stallion culture results and postbreeding uterine culture results, as well as the effect of bacterial types found on the stallion cultures with bacterial types found on the postbreeding uterine cultures. Of stallion cultures, 22.4% were positive for potentially pathogenic bacteria, with Streptococcus equi subspecies zooepidemicus (51.1%) being the most common isolate. Uterine cultures resulted in a 29.2% positive rate for potentially pathogenic bacteria, with S. equi subsp. zooepidemicus (90.9%) being the most common. There was no difference (P > .05) in the occurrence of bacteria or type of isolate found on uterine cultures after breeding stallions with or without positive cultures. In conclusion, potentially pathogenic bacteria found on the stallion's external genitalia did not affect the occurrence and type of bacterial isolate found in the mare's uterus after breeding by live cover.     

Aerobic bacterial flora of the nasal cavity in Gulf of California sea lion (Zalophus californianus) pups

Nasal swab samples from clinically healthy California sea lions pups (Zalophus californianus) from six different reproductive rookeries in the Gulf of California were collected to determine the type and frequency of the representative aerobic bacterial microflora of their nasal mucosa. A total of 114 samples were examined and 100 bacterial isolates were identified and typified by microbiological and biochemical standard tests. Fifty four isolates corresponded to Gram positive bacteria (54%) and 46 isolates to Gram negative bacteria (46%). Fifteen bacterial genera were identified, including Micrococcus, Arcanobacterium, Corynebacterium, Moraxella, Neisseria, Escherichia, Kurthia, Acinetobacter, Staphylococcus, Brevibacillus, Bacillus, Klebsiella, Stenotrophomonas, Pseudomonas and Aeromonas. The most frequently isolated genera were Moraxella (24%), Micrococcus (18%), and Corynebacterium (15%). These results show the presence in the nasal cavity of sea lions of several microorganisms. Although considered part of the normal microflora, they may also be opportunistic pathogens for their hosts and may act as a potential natural sentinel of environmental changes.