Obligately anaerobic bacterial species isolated from foot-rot lesions in goats

Lesions showing clinical signs of foot-rot from 120 goats were cultured on six selective media during October 1987 to November 1988. A total of 582 strictly anaerobic microorganisms belonging to 50 different species was isolated and identified. The anaerobes most frequently isolated belonged to the following genera: Bacteroides (80%), Peptostreptococcus (63.6%), Megasphaera (40%), Fusobacterium (29.2%), Clostridium (22.5%), Propionibacterium (12.5%), Eubacterium (11.7%) and Leptotrichia (10.8%). Percentages for Acidaminococcus, Peptococcus, Tissierella, Wolinella and Veillonella were below 10%. The following species were identified in 10% or more of cases: Peptostreptococcus anaerobius (61.7%), Bacteroides buccae (51.7%), Bacteroides nodosus (42.5%), Megasphaera elsdenii (40%), Bacteroides ruminicola subsp. brevis (22.5%), Fusobacterium necrophorum (19.2%), Leptotrichia buccalis (11.7%) and Clostridium perfringens (10%). Lower percentages were obtained for the remaining species. The efficiency and selectivity of the six culture media used for isolation are discussed.     

Gram-negative anaerobes in the intestinal flora of pigs

A differential count of the gram-negative, anaerobic, non sporeforming bacteria in different segments of the pig intestinal tract was performed in 2 groups of pigs. Seventy-seven strains were identified, belonging to 6 groups: Sphaerophorus necrophorus, anhemolytic Sphaerophorus spp., Bacteroides (Eggerthella) spp., Fusobactenum spp., Veillonella/Acidaminococcus spp., and Peptostreptococcus elsdenii. The characters of these groups are described, and quantitative data on their occurrence in a group of normal porkers and a group of pigs with experimental swine dysentery are given.     

Changes in prevalence and susceptibility of obligate anaerobes in clinical veterinary practice

Of 3,133 clinical specimens obtained from domestic animals, 26% contained species of bacteria that were obligate anaerobes. Members of the genera Bacteroides, Fusobacterium, and Peptostreptococcus accounted for 77% of the isolates. On the average, 2 species of obligate anaerobes were found in each specimen, usually admixed with facultatively anaerobic bacteria. Of those specimens containing an obligate anaerobe, 20% contained one isolate that was resistant to penicillin, ampicillin, and cephalothin. These resistant isolates belonged to the genus Bacteroides, the most common being Bacteroides fragilis. Approximately one third of these penicillin-resistant isolates was resistant to tetracycline as well. All isolates were susceptible to chloramphenicol, tetracycline (excluding penicillin-resistant Bacteroides), metronidazole, and clindamycin.     

Occurrence of anaerobic bacteria in diseases of the dog and cat.

A survey for anaerobic bacteria was conducted in 314 clinical specimens from dogs and cats. A total of 187 anaerobic isolates in pure and mixed culture were isolated from 111 of the specimens that contained anaerobic bacteria. Common isolated included Actinomyces (9.1%), Clostridium perfringens (19.3%), other Clostridium spp (11.2%), Peptostreptococcus anaerobius (7.5%), Bacteroides melaninogenicus (13.4%), other Bacteroides spp (17.6%), and Fusobacterium necrophorum (5.3%). Anaerobic bacteria were involved in serious lesions that often were life threatening to the animals. Antibiotic susceptibility data indicated that the lincomycin family, the penicillin family, chloramphenicol, and cephaloridine are preferred drugs for treatment of anaerobic infections. Data from the survey were used in formulation of a table to aid practitioners in clinical diagnosis of disease caused by anaerobes. Clostridium perfringens was isolated in large numbers from five of six dogs with a clinical diagnosis of canine hemorrhagic gastroenteritis and from one cat with hemorrhagic diarrhea. Experimental infections were induced in rats, using caine feces as inoculum. Induced lesions contained aerobic and anaerobic bacteria similar to those bacteria isolated in the clinical survey, indicating that feces may serve as a major source of these bacteria in clinical infections of the dog.     

Evaluation of subgingival bacteria in the dog and susceptibility to commonly used antibiotics

The aim of the present investigation was to evaluate the subgingival aerobic and anaerobic flora of 13 dogs with periodontal disease and the susceptibility of these bacteria to antibiotics currently approved in Italy for treatment of canine infections. Of the anaerobic bacteria, Bacteroides fragilis was most frequently isolated, followed by Peptostreptococcus + Porphyromonas gingivalis and Prevotella intermedia. Of the aerobic bacteria, alpha-hemolytic Streptococcus was most frequently isolated, often associated with Escherichia coli or Pasteurella multocida. Resistance of anaerobic and aerobic bacteria to various antibiotics was generally high. Anaerobic bacteria appeared to be susceptible to amoxicillin + clavulanic acid, doxycycline, and erythromycin; aerobic bacteria appeared to be susceptible to amoxicillin + clavulanic acid, erythromycin, gentamycin, and sulfa-trimethoprim. Bacteroides fragilis was resistant to all of the antibiotics tested. The emerging worldwide problem of bacterial resistance to antibiotics resulting from overuse and misuse of antibiotics is discussed.     

Oral associated bacterial infection in horses: studies on the normal anaerobic flora from the pharyngeal tonsillar surface and its association with lower respiratory tract and paraoral infections

Two hundred and seventy bacterial isolates were obtained from the pharyngeal tonsillar surface of 12 normal horses and 98 obligatory anaerobic bacteria were characterised. Of these, 57 isolates belonging to 7 genera (Peptostreptococcus (1); Eubacterium (9); Clostridium (6); Veillonella (6); Megasphera (1); Bacteroides (28); Fusobacterium (6)) were identified, and 16 of these were identified to species level (P. anaerobius (1); E. fossor (9); C. villosum (1); B. fragilis (1); B. tectum (2); B. heparinolyticus (2)). Three hundred and twenty isolates were obtained from 23 samples from horses with lower respiratory tract (LRT) or paraoral (PO) bacterial infections. Of the 143 bacteria selected for detailed characterisation, obligate anaerobes accounted for 100 isolates, facultative anaerobes for 42 isolates and obligate aerobes for one isolate. Phenotypic characterisation separated 99 of the isolates into 14 genera. Among the obligately anaerobic species, Gram-positive cocci including P. anaerobius comprised 25% of isolates, E. fossor 11% and other Gram-positive rods (excluding Clostridium sp.) 18% of isolates. The Gram-negative rods comprised B. fragilis 5%, B. heparinolyticus 5%, asaccharolytic pigmented Bacteroides 3% and other Bacteroides 13%, while a so-far unnamed species of Fusobacterium (7%), and Gram-negative corroding rods (3%) were isolated. Among the facultatively anaerobic isolates, S. equi subsp. zooepidemicus accounted for 31% of isolates, followed by Pasteurella spp. 19%, Escherichia coli 17%, Actinomyces spp. 9%, Streptococcus spp. 9%. Incidental facultative isolates were Enterococcus spp. 2%, Enterobacter cloaceae 2%, Actinobacillus spp. 2% and Gram-negative corroding rods 5%. On the basis of the similarities (as determined by DNA hybridization data and/or phenotypic characteristics) of some of the bacterial species (e.g. E. fossor and B. heparinolyticus) isolated from both the normal pharyngeal tonsillar surfaces and LRT and PO diseases of horses, it is considered that the most likely source of bacteria involved in these disease processes is flora from the oral cavity.     

Osteomyelitis in dogs and cats caused by anaerobic bacteria

Localised osteomyelitis was diagnosed in 2 dogs and 2 cats. The disease was caused by fight wounds in 3 cases. Radiographic examination demonstrated a circumscribed zone of cortical bone lysis, sequestra and periosteal new bone. Each case was treated surgically by sequestrectomy and debridement. Infection was due mainly to anaerobic bacteria. The pathogenic bacteria isolated from the lesions of dogs were Actinomyces viscosus, Fusobacterium nucleatum and Bacteroides spp, and from the lesions in cats were Clostridium villosum , Peptostreptococcus anaerobius, Wolinella recta and Bacteroides gingivalis. As all the bacteria were sensitive to penicillin, each case was treated with penicillin and by irrigation of the wound. This resulted in resolution of the disease, within 4 weeks, in all cases.     

The obligate and facultatively anaerobic bacterial flora of the normal feline gingival margin

Samples from the gingival margins of 14 cats considered normal on clinical examination were cultured for facultative and obligate anaerobic bacteria. All mouths were free from any gingival marginal inflammation and tartar build-up; all cats were between 6 and 12 months of age. A mixed growth was obtained from all samples. The mean number of bacterial species per sample was 10.7 with a range of 7-16 isolates. Of the 150 isolates processed, 109 (72.66%) were obligate anaerobes. Of the facultatively anaerobic species, Actinomyces (including A. viscosus, A. hordeovulneris and A. denticolens) comprised 12%, Pasteurella multocida 9.33% of isolates and Propionibacterium species 6% of all isolates. Gram-negative bacilli belonging to the genera Bacteroides and Fusobacterium were isolated from 12 of the 14 samples, and comprised 77% of the obligate anaerobes isolated. Clostridium villosum comprised 10.1% of obligately anaerobic isolates, Wolinella species made up 6.42%, while 4.58% were Peptostreptococcus anaerobius. The most commonly isolated obligately anaerobic species was C. villosum and the most commonly isolated facultatively anaerobic species was P. multocida. These findings show a bacterial flora of the normal feline mouth which is very similar in composition to that of cat fight abscesses and feline pyothorax.     

Isolation and identification of intestinal bacteria from Japanese tree frog (Hlya japonica) with the special reference to anaerobic bacteria.

The bacteria in the large intestines of eight Japanese tree frogs (Hlya japonica) were enumerated by using an anaerobic culture system. The microorganisms at approximately 3.1 x 10(9) bacteria per g (wet weight) of intestinal contents were present in the intestine of all the frogs tested. No difference of the total bacteria in the frog intestine was observed between two different incubation-temperatures (room temperature and 37 degrees C). Eleven genera and 16 species were isolated from the frog intestine. In most frogs, Bacteroides (B.) caccae and B. vulgatus were detected as the predominant organisms. Escherichia coli was also present in greater numbers in the intestine. Other bacteria isolated at high dilutions were strict anaerobes, including Fusobacterium and Clostridium. Enterococcus faecalis was frequently isolated from the frog intestine. However, four genera of Bifidobacterium, Eubacterium, Peptostreptococcus, and Lactobacillus were not isolated from the frog intestine.     

Central Nervous System Infection Associated With Anaerobic Bacteria in Two Dogs and Two Cats

Central nervous system (CNS) infection caused by anaerobic bacteria (including Bacteroides, Fusobacterium, Peptostreptococcus, and Eubacterium) was diagnosed in two dogs and two cats. In one dog there was extensive meningomyeloencephalitis, presumably the result of hematogenous spread of bacteria from lung abscesses and bacterial endocarditis. Subdural empyema of unknown origin was found in a second dog and two cats. Clinical signs in all four animals included mental depression and focal neurologic deficits, without fever.     

Bacteroides species from the oral cavity and oral-associated diseases of cats

One hundred and sixty-seven strains of Bacteroides were isolated from 71 subcutaneous fight-wound abscesses of cats, 21 cases of feline pyothorax, normal gingival margins from 10 cats and 6 cases of feline gingivitis. Bacteroides species constituted (as a proportion of all anaerobic isolates examined) 44.5% from subcutaneous abscesses, 33.7% from pyothoraxes, 37.5% from normal gingiva and 27.7% from diseased gingiva. Bacteroides tectum comprised 43.7% or 73 of 167 strains, followed by the black- or brown-pigmented asaccharolytic feline species of B. gingivalis, B. salivosus and Group B, comprising 32.3% or 54 of 167 strains. B. heparinolyticus (some 10% or 17 of 167 strains) was the next most common species described. The remainder consisted of two strains of B. fragilis and 21 unspeciated strains. Bacteroides tectum was frequently isolated from subcutaneous abscesses (43.7%) and pyothoraxes (46.6%), and it constituted some 33% of anaerobic isolated from normal gingiva. Bacteroides heparinolyticus was more commonly encountered in purulent lesions (abscesses and pyothoraxes) than in the oral cavity.     

Identity of Bacteroides isolates and previously named Bacteroides spp in clinical specimens of animal origin.

During the years 1984 through 1987 2,574 isolates of obligately anaerobic bacteria were isolated from samples submitted for analysis. The most common anaerobic isolates were members of the genus Bacteroides, representing 44.6% of the isolates. Of these, the most commonly isolated identifiable microorganisms were bile-resistant and nonpigmented, belonging to the B fragilis group of Bacteroides. Importantly, obvious predilections for any one species or group of Bacteroides were not apparent for animal or site (condition), except that the proportion of isolates belonging to the nonpigmented, bile-resistant group obtained from the respiratory tract was significantly (P less than 0.005) higher than that not belonging to this group. On the other hand, the proportion of isolates of the non-pigmented, bile-resistant group obtained from abscesses was significantly lower than that not belonging to this group.     

Anaerobic bacterial pericardial effusion in a cat

A 9-year-old male cat was presented for evaluation of chronic weight loss and was subsequently diagnosed with pericardial effusion. The effusion was quantified as a septic exudate caused by the anaerobic bacterium Peptostreptococcus. Antibiotic therapy resulted in complete resolution of the pericardial effusion. As Peptostreptococcus is a common oral bacterium and the cat had a previous dental procedure, it is speculated that the pericardial effusion was secondary to bacteraemia from the dental procedure.     

Identification of some anaerobic bacteria in nonspecific anaerobic infections in animals.

Over 200 anaerobic bacterial isolates were recovered in a veterinary diagnostic laboratory from nonspecific infectious disease from 72 specimens originating from ten animal species. The majority of isolates were nonsporeforming bacteria and about half were identified to species. Bacteroides species formed the major group and included B. oralis, B. fragilis, B. corrodens, B. ruminicola subspecies ruminicola, B. ruminicola subspecies brevis and various subspecies of B. melaninogenicus. Gram-positive anaerobic cocci constituted the next major group of isolates and the main species identified in cattle was Peptococcus indolicus. Clostridial species were uncommon. Nine specimens yielded a pure culture of an anaerobe and, in samples containing mixtures of bacterial species, each specimen yielded an average of 3.1 anaerobic and 1.4 aerobic bacterial species. The failure to identify many of the isolates is discussed.     

Use of nonprotein nitrogen in pigs: effects of dietary urea on the intestinal microflora

The fecal flora of 2 pigs given an optimal protein diet (digestive crude protein, 13.3%) with 2% urea, 2 pigs given a low protein diet (digestive crude protein, 5.7%) with 2% urea, and 2 pigs given a low protein diet only were bacteriologically investigated before feeding of each diet and on feeding days 21 and 38. The addition of urea to a low protein diet was significantly decreased Lactobacillus (P less than 0.001), Bacteroidaceae (P less than 0.01), Peptococcaceae (P less than 0.05), and Megasphaera (P less than 0.01) in the feces. In addition, there was a marked suppression of anaerobic curved rods (mainly Selenomonas) to undetectable amounts in the feces. A significant reduction (P less than 0.01) of Bifidobacterium and a marked suppression of Megasphaera to undetectable amounts were observed in the feces of pigs given low protein diets without urea. Microbial groups in the ileum and colon of pigs on feeding day 38 were also analyzed. Effects of dietary urea on the intestinal flora included: (i) anaerobic curved rods and spiral rods were restricted mainly to the colon, (ii) smaller numbers of yeasts were present in the intestine, and (iii) Bacteroidaceae, Peptococcaceae, and Eubacterium in the colon were not changed. Many anaerobic isolates, including curved rods and spiral rods, in the colon of pigs may have an important role in urea use.     

Comparative bacteriological studies on summer mastitis in grazing cattle and pyogenes mastitis in stabled cattle in Denmark.

A total of 143 secretions from clinical cases of summer mastitis (SM) in grazing cattle and from 89 cases of pyogenes mastitis (PM) in stabled cattle were examined bacteriologically. The typical bacteriological finding was a mixed flora in which the predominant organisms were Actinomyces pyogenes (SM-70%, PM-85%), Peptostreptococcus indolicus (54%, 54%), a microaerophilic coccus (Stuart-Schwan coccus) (26%, 25%), Fusobacterium necrophorum biovar B (22%, 12%), Bacteroides melaninogenicus (20%, 9%) and Streptococcus dysgalactiae (21%, 5%). All except six cases occurred in non-lactating animals or within three weeks after parturition. The majority of animals (about 90%) had only one quarter affected and no differences in quarter distribution were observed between the two groups.     

Characterisation of a new phage lytic for both smooth and non-smooth Brucella species

A brucella phage of the Izatnagar series, designated Iz1, was lytic for all Brucella species that are normally smooth, although the efficiency of plating varied between biovars and species. The phage was also lytic for rough strains of B melitensis and B suis and, to a lesser extent, B ovis. It displayed negligible lytic activity towards B canis and rough B abortus cultures. In its morphological and serological properties and its stability to inactivating agents, the Iz1 phage resembled other brucella phages.     

鸡肠道菌基因组DNA的RAPD分类的研究

本文以7种鸡肠道菌为研究对象，分别提取基因组DNA，利用随机扩增多态性DNA（RAPD）技术对其基因组进行DNA分析，筛选出一系列随机引物，能在7种肠道细菌中有较好的多态性，可用作分子标记鉴别这7种肠道菌。     

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.     

Chromosomal DNA probes for the identification of asaccharolytic anaerobic pigmented bacterial rods from the oral cavity of cats.

A dot-blot hybridisation assay using isolated high molecular weight DNA as whole chromosomal probes of the cat pigmented asaccharolytic Bacteroides/Porphyromonas species was used against both purified high molecular weight DNA and DNA released on membranes from whole cells for the identification of B. salivosus and for its differentiation from the other anaerobic species isolated from normal and diseased mouths of cats and horses. 32P-labelled probes were compared with digoxigenin (DIG)-labelled probes (Boehringer-Mannheim). The whole chromosomal probes were specific--differentiating B. salivosus from a variety of species (including members of the genera Bacteroides, Fusobacterium, Eubacterium, and Prevotella) found in normal and abnormal mouths of cats and horses. Likewise, asaccharolytic black pigmented Group 2 strains were distinguishable from all strains tested. However, cat strains of P. gingivalis which show 68-76% DNA-DNA homology with human strain P. gingivalis ATCC 33277T, were not distinguishable from each other using either 32P-labelled or DIG-labelled probes. The minimum amount of pure Bacteroides DNA which could be detected by the 32P-labelled probe was 100-300 pg, while the amount of pure DNA detected by the DIG system was 1-3 mg after room temperature colour development for 1 h and 100-300 pg after 6 h colour development.