Comparative in vitro susceptibility of Bacteroides and Fusobacterium isolated from footrot in sheep to 28 antimicrobial agents

The agar dilution method was used to determine the bacteriostatic activity of 28 antimicrobial agents against 141 strains to the genus Bacteroides and 29 strains from the genus Fusobacterium. All organisms were isolated from clinical cases of ovine footrot. The strains were isolated from 125 Merino sheep, over a period of 2 years, from January 1987 to December 1988. The three ureidopenicillins studied (azlocillin, mezlocillin and piperacillin) proved to be the most effective antimicrobial agents. Chloramphenicol, metronidazole and tinidazole effectively inhibited the growth of Bacteroides spp., while phosphomycin was active against Fusobacterium spp.     

In-vitro antimicrobial susceptibility of Bacteroides and Fusobacterium isolated from footrot in goats

The agar dilution method was used to determine the antimicrobial activity of 17 antimicrobial agents against 132 strains belonging to the genus Bacteroides and 25 strains from the genus Fusobacterium, all isolated from 120 clinical cases of caprine footrot between October 1987 and November 1988. Josamycin, chloramphenicol and rifampin proved to be the most effective antibiotics in vitro. Significant resistance was found to the other antimicrobial agents studied.     

Minimum inhibitory concentrations for selected antimicrobial agents against Fusobacterium necrophorum isolated from hepatic abscesses in cattle and sheep

Minimum inhibitory concentrations for 35 antimicrobial agents against 100 Fusobacterium necrophorum isolates from hepatic abscesses in sheep and cattle were determined. Twelve of the thirteen β-lactam antibiotics tested inhibited growth of 100% of strains tested. Of the remaining antimicrobial agents, extensive susceptibility was found for: spiramycin, josamycin, lincomycin, tylosin, oxytetracycline, chlortetracycline, rufloxacin, metronidazole, co-trimoxazole, sulfadimethoxine, virginiamycin and fosfomycin.     

Microbiological study of foot-rot in lambs: isolation, elastolytic activity and antimicrobial susceptibility.

A microbiological study was made of an outbreak of foot-rot in lambs. Elastolytic activity was detected in all 10 Bacteroides nodosus strains isolated from the hooves of 9 affected animals. Among 14 other isolated strictly anaerobic microorganisms belonging to different species or genera only 4 strains showed a low degree of elastolysis. The 14 antimicrobial agents studied effectively inhibited "in vitro" growth of B. nodosus.     

Susceptibility of Bacteroides nodosus to various antimicrobial agents

The susceptibility of 18 strains of Bacteroides nodosus to 21 antimicrobial agents was tested in vitro. Penicillin was the most effective antibiotic tested. Other antibiotics tested, in order of relative efficacy, were cefamandole, clindamycin, tetracycline, chloramphenicol, erythromycin, sodium cefoxitin, tylosin tartrate, nitrofurazone, tinidazole, and dihydrostreptomycin sulfate. Tests of solutions of 4 antibiotics in 70% ethanol indicated that ethanol served primarily as a diluent and did not contribute substantially to the curative effect of such topical medications on foot rot lesions in sheep. Of the chemicals commonly used in foot baths for treatment of ovine foot rot, copper sulfate was most effective, followed by zinc sulfate, then formalin. Several commercial disinfectants and iodine were quite effective against B nodosus, whereas 5.25% sodium hypochlorite and 70% ethanol alone were relatively ineffective.     

Comparative antigenic analysis of extracellular proteins of Bacteroides nodosus isolated from virulent and benign ovine footrot

Antigens in the extracellular protein (ECP) complexes of Bacteroides nodosus, isolated from sheep with either benign or virulent footrot, were studied by immunoelectrophoresis (IEP). Rabbit antisera against ECP from virulent and benign strains, were used in homologous and heterologous crossed IEP. Four precipitin peaks unique to the virulent strain, and five peaks unique to the benign strain were identified. In an attempt to characterize the different antigens in ECP, rabbit antisera were raised against an outer membrane protein (OMP, mol. wt. 35 000 daltons), pili and various proteases of virulent and benign strains of B. nodosus. No precipitin band was observed when ECP from both B. nodosus strains were reacted against anti-OMP and anti-pilus antisera. However, single precipitin bands unique to one protease from the benign strain and one protease from the virulent strain were identified. The results suggest that specific antigens other than proteases or pili are important in determining whether a B. nodosus isolate is virulent or benign.     

In vitro antimicrobial susceptibility of anaerobic bacteria isolated from caprine footrot

The in vitro antimicrobial susceptibility of Gram-negative anaerobic bacilli commonly isolated from footrot in goats was studied. A total of 97 isolates belonging to the genera Dichelobacter, Fusobacterium, Prevotella, Porphyromonas and Bacteroides, obtained from clinical cases of footrot in south-western Spain between March 2000 and May 2001, were tested against 25 antimicrobial agents comprising beta-lactams, aminoglycosides, macrolides, chloramphenicol, quinolones, lincosamides, sulphonamides and tetracyclines in order to optimise antibiotic treatment of this disease in goats. beta-lactams, tetracyclines and metronidazole displayed the highest in vitro efficacy against the species involved in the pathogenesis of footrot.     

Antimicrobial susceptibility of Pasteurella multocida and Bordetella bronchiseptica from dogs and cats as determined in the BfT-GermVet monitoring program 2004-2006

A total of 92 canine/feline Pasteurella multocida strains form respiratory tract infections or infections of skin/ear/mouth as well as 42 canine/feline Bordetella bronchiseptica strains from respiratory tract infections were investigated for their susceptibility to antimicrobial agents. While the P. multocida strains were susceptible to all antimicrobial agents tested - except sulfonamides -, a considerable number of the B. bronchiseptica strains was resistant or exhibited high MIC values against a number of antimicrobial agents including penicillin G, oxacillin, cefazolin, ceftiofur, cefquinome, sulfamethoxazole, and trimethoprim/sulfamethoxazole.     

Isolation and identification of anaerobic bacteria from ovine foot rot in Spain

A microbiological study was made of 125 Merino sheep showing clinical signs of foot rot. A total of 435 strictly anaerobic strains were isolated, belonging to the following genera: Bacteroides, Peptostreptococcus, Tissierella, Fusobacterium, Megasphaera, Eubacterium, Acidaminococcus, Clostridium, Peptococcus and Propionibacterium. Of the 35 species obtained, the following were found in more than 10 per cent of animals sampled: Bacteroides nodosus, B putredinis, B buccae, B ruminicola subspecies brevis, Tissierella praeacuta, Peptostreptococcus anaerobius and Megasphaera elsdenii. Six culture media were used for isolation. Agar brucella and agar brucella enriched with G-N anaerobe supplement proved to be the most efficient for isolating anaerobic bacteria.     

大肠杆菌分离鉴定及其耐药性试验

为了确定采集自内蒙古地区某牧场的病料内的病原菌,对其进行细菌的分离培养。将分离培养出的2株病原菌进行16S rDNA扩增、细菌生化鉴定、致病性试验以及细菌耐药性试验。结果表明,分离菌在伊红美蓝琼脂培养基上可生长出暗红色或黑色并且带有金属光泽的菌落;镜检可见,分离菌为革兰阴性杆菌;分离菌生化鉴定结果与大肠杆菌标准菌株ATCC 25922测定的结果相一致;分离菌的16S rDNA与大肠杆菌标准菌株16S rDNA PCR扩增结果相一致;分离到的2株大肠杆菌均具有致病性,对多种抗生素均有耐药性。结果提示,该次分离得到的病原菌主要为具有多重耐药性的致病性大肠杆菌。     

Aetiology of caprine footrot in Extremadura region, Spain

The present study reports on the location of major foci of footrot in goats in the Extremadura region of Spain by the determination of locally occurring strictly anaerobic microorganisms involved in the pathogenesis and development of this disease. The most commonly isolated microorganisms belonged to the genera Dichelobacter, Fusobacterium, Porphyromonas and Prevotella; these were found in conjunction with other species of minor importance. The species most frequently isolated were Fusobacterium necrophorum (40%), Dichelobacter nodosus (31.7%), Porphyromonas asaccharolytica (21.1%) and Prevotella melaninogenica (12.9%). Virulence factors identified in the isolated microorganisms included haemolysins, elastases and lecithinases, which enabled the organisms involved to initiate and/or aggravate the disease. Serotyping was performed for Dichelobacter nodosus isolates, since this species is responsible for triggering the process of infection. A and C were the most frequently isolated serovarieties (representing 40.7% and 25.9% of the cases, respectively).     

Phenotypic characterization and random amplified polymorphic DNA (RAPD) analysis of Pasteurella multocida isolated from Korean pigs

Pasteurella multocida causes various respiratory disease symptoms in pigs, including atrophic rhinitis and pneumonia. In the present study, 69 strains of P. multocida were isolated from 443 pigs with respiratory clinical symptoms at 182 farms located throughout South Korea from 2009 to 2010. A multiplex capsular PCR typing assay revealed that 69 strains of P. multocida isolated in this study had the biosynthetic locus of the capsules of either serogroup A (47 strains, 68.1%) or serogroup D (22 strains, 31.9%). The 22 strains positive for serogroup D-specific primers were divided into four clusters and the 47 strains positive for serogroup A-specific primers were divided into 12 clusters according to the results of Random Amplified Polymorphic DNA (RAPD) analysis. P. multocida strains in the present study were susceptible to most of the antimicrobial agents used. An analysis of antimicrobial resistance and virulence gene pattern combined with RAPD indicated that a certain P. multocida strain appeared to be genetically identical, implying the persistence of the strain within a single farm.     

Update on ovine footrot in New Zealand: isolation, identification, and characterization of Dichelobacter nodosus strains [corrected

Dichelobacter nodosus, a Gram-negative strict anaerobe, is the essential causative agent of ovine footrot. Despite its worldwide presence, the disease has significant economic impact in those sheep-farming countries with a temperate climate and moderate to high rainfall, such as New Zealand (NZ) and Australia. In this study, we aimed to isolate, identify, and characterize as many D. nodosus strains as possible from NZ farms by using polymerase chain reaction (PCR)-based technology. Understanding the virulence of this bacterium and showing extensive genomic variation in the fimbrial subunit gene (fimA) in different D. nodosus strains was very important to produce serogroup specific and effective vaccine for NZ. More than 100 footrot samples were collected from four different farming regions in NZ. Thousands of primary plates were cultured anaerobically and examined with Gram-staining in order to detect single colonies of D. nodosus. Approximately 500 plates that had potential D. nodosus colonies were subcultured several times to eliminate contaminating colonies until single colonies were obtained. Variable and a part of the conserved regions of the fimbrial subunit gene (fimA) were amplified directly from bacterial DNA extracted from footrot lesions and also from cultured NZ D. nodosus isolates, using the polymerase chain reaction. Different fimA amplimers were analyzed by DNA sequencing. On the basis of DNA sequence analysis, 16 new D. nodosus isolates belonging to eight different serogroups were identified from NZ. These new D. nodosus fimA sequences from NZ were different to previously reported strains and strains used in a commercial vaccine.     

大肠杆菌多重耐药株的体外诱导初步研究

为了解不同抗菌药物对大肠杆菌体外耐药诱导株的MIC变化特点,以盐酸四环素、盐酸环丙沙星、水杨酸钠、氯霉素作为诱导剂,采用1／2×MIC诱导法,对大肠杆菌质控菌株ATCC25922进行体外诱导试验。于诱导前对试验菌株进行形态学观察和生化鉴定,并于诱导过程中对试验菌株进行形态学观察。于诱导前测定16种抗菌药物对质控菌株的MIC,并于诱导剂浓度达到128×MIC时,测定16种抗菌药物对4株诱导菌株的MIC。结果表明,试验菌株的形态特征和生化反应特性与大肠杆菌一致。诱导前,16种抗菌药物对质控菌株的MIC为0．25-64．00μg／mL;头孢噻肟、盐酸四环素、土霉素、甲砜霉素、诺氟沙星、头孢西丁等抗菌药物对盐酸四环素诱导株的MIC与质控菌株相比．提高幅度均达到或超过4倍,均具有显著性意义;头孢噻肟对盐酸环丙沙星诱导株和氯霉素诱导株的MIC与质控菌株相比．提高倍数都超过了4倍,而其余抗菌药物的MIC变化均无显著性意义。水杨酸钠诱导剂浓度大于16×MIC时,菌株不能生长。结果提示。抗菌药物对盐酸四环素诱导株的MIC变化最明显,表明大肠杆菌在四环素的选择性压力下较易产生耐药性。     

Susceptibility of Bacteroides from swine abscesses to 13 antibiotics

The minimal inhibitory concentrations (MIC) of 129 strains of genus Bacteroides, isolated from abscesses in pigs, for 13 different antimicrobial agents were determined by an agar-dilution method under anaerobic conditions. Clindamycin, the most active antibiotic tested, had a median MIC of 0.8 micrograms/ml. Penicillin G, talampicillin, minocycline, chloramphenicol, and cefoxitin also inhibited all isolates at lower concentrations. Some isolates of B pyogenes were susceptible to gentamicin (MIC, 0.4 micrograms/ml), erythromycin (MIC, 0.8 micrograms/ml), cephalexin (MIC, 0.8 micrograms/ml), and cefoxitin (MIC, 3.2 micrograms/ml). Erythromycin, at a concentration of 3.2 micrograms/ml, was active against 70% of B suis tested, but it was less active against the other Bacteroides species. Some strains tested were resistant to streptomycin and neomycin.     

Occurrence of different strains of Dichelobacter nodosus in new clinical lesions in sheep exposed to footrot associated with multi-strain infections

OBJECTIVE: To investigate the occurrence of S1, U1 and T strains of Dichelobacter nodosus in new clinical lesions in sheep exposed to footrot associated with multi-strain infections. DESIGN: Seventy-seven donor sheep were grazed with 84 recipients for 33 weeks. The donor sheep were Merinos with a history of clinically virulent footrot associated with protease type S1, U1 and T strains of D nodosus that hybridised with gene sequences pJIR314B, pJIR318 and/or pB645-335. The recipient sheep were Merinos with no history of footrot. PROCEDURE: Each fortnight, all feet were examined, their lesion scores were recorded and samples of lesion material were taken for laboratory tests. RESULTS: Eighty-nine percent (299 of 336) of feet of recipient sheep developed new clinical lesions. S1, U1 and T strains of D nodosus were recovered from 58%, 22% and 18%, respectively, of these lesions at a ratio that remained constant during two apparent peaks in footrot transmission. Gene sequences homologous to pJIR314B and pB645-335 were detected in 56% (93 of 166) and 29% (48 of 166), respectively, of S1 strains of D nodosus at a ratio that was not constant during the experiment. CONCLUSIONS: S1 was the dominant protease type of D nodosus in new clinical lesions. The occurrence of S1 strains did not increase relative to U1 and T strains of D nodosus during the experiment. S1, U1 and T strains of D nodosus remained in equilibrium despite changes in environment, genetic types in the population of S1 strains, and host resistance to footrot.     

Antimicrobial resistance determinants among anaerobic bacteria isolated from footrot

Antibiotic resistance has been evaluated among 36 Gram negative and anaerobic bacilli (10 Bacteroides, 11 Prevotella, 7 Porphyromonas and 8 Fusobacterium strains) isolated from clinical cases of caprine and ovine footrot (necrotic pododermatitis). The initial analysis on this bacterial consortium evaluates the relationships existing among antimicrobial resistance determinants, phenotype expression and mobilization potential. The Bacteroides strains were generally resistant to penicillins, first-generation cephalosporins, tetracycline and erythromycin, and expressed low level of β-lactamase activity. The main determinants found among the Bacteroides strains were cepA and tetQ genes, conferring resistance to β-lactams and tetracycline, respectively. A general susceptibility to β-lactams was shown for most Prevotella, Porphyromonas and Fusobacterium strains, where none of the β-lactamase genes described in Bacteroides was detected. Resistance to tetracycline and/or erythromycin was found among the three bacterial groups. Although tetQ genes were detected for several Prevotella and Porphyromonas strains, a unique ermF positive was revealed among Prevotella strains. The expression of resistance markers was not related with the polymorphism of their coding sequences. However, the finding of sequence signatures for conjugative transposons in the vicinities of tetQ and ermF suggests a mobilization potential that might have contributed to the spread of antimicrobial resistance genes.     

Laminitis and interdigital dermatitis and heel horn erosion. A European perspective

Laminitis is one of the most important claw disorders in dairy herds. Nutrition, calving, burdening of the lateral claw of the rear feet, and hereditary susceptibility are all contributing factors. Interdigital dermatitis in cattle may be a result of infection by Bacteroides nodosus and Fusobacterium necrophorum. If this infection becomes chronic, heel horn erosion is its consequence.     

Vaccination against lumpy jaw and measurement of antibody response in wallabies (Macropus eugenii)

Successful protection against lumpy jaw disease in a colony of captive wallabies (Macropus eugenii) was induced by vaccination with a commercial ovine footrot vaccine. No mortalities attributable to lumpy jaw were observed in 69 vaccinated animals while six of 42 unvaccinated control wallabies died of the disease. Vaccinated animals exhibited significant increases in antibody titres to Bacteroides nodosus after the first and second doses of vaccine. Titres were measured by an enzyme-linked immunosorbent assay.     

The BfT-GermVet monitoring program--aims and basics

To determine the current status of antimicrobial susceptibility of bacterial pathogens from animals in Germany, the Bff-GermVet monitoring program was initiated as a complementary program to the German national monitoring program GERM-Vet conducted by the Federal Office of Consumer Protection and Food Safety (BVL). In the Bff-GermVet program, a total of 1,626 bacterial strains, obtained during a 27-month period (01/2004-03/2006) from 31 indications, was screened for susceptibility against 22 antimicrobial agents and two combinations of antimicrobial agents. Selected bacteria were additionally tested for their susceptibility against additional three combinations of antimicrobial agents and the corresponding single substances.This paper describes the overall aims and the structure of the program with particular reference to the sampling strategy, the methodology for susceptibility testing and the interpretive criteria used for evaluation of the results.