Airborne Gram‐Negative Bacterial Flora in Animal Houses

The concentration and the species composition of airborne gram‐negative bacteria were studied in four cattle houses, one pig house and one poultry barn. On average only between 0.02 and 5.2 % of the total number of culturable aerobic bacteria were identified as gram‐negative bacteria. Obligate anaerobic gram‐negative bacteria were not isolated at all. In the airborne gram‐negative bacterial flora the following bacterial families dominated: the Enterobacteriaceae, the Pseudomonadaceae and the Neisseriaceae. Within the family of the Enterobacteriaceae the species Escherichia coli and Enterobacter agglomerans were predominant. In animal houses using straw as bedding material Ent. agglomerans was most frequent, whereas in animal houses without litter E. coli was mainly found. Airborne Neisseriaceae were isolated very frequently in cow barns with Acinetobacter lowffii as the primary species. Airborne Pseudomonadaceae were found in high concentrations during periods of high air humidity. The results presented may also give some indications on the origin and sources of airborne endotoxins in animal housing.     

Air microorganisms in animal housing--4. Airborne gram-negative bacteria and airborne endotoxin in pig houses

The species composition of airborne gram-negative bacteria and the relationship between inhalable endotoxin, inhalable dust and airborne bacteria were studied in 4 pig houses. The airborne gram-negative bacterial flora was dominated by Enterobacteriaceae. Within the Enterobacteriaceae the species E. coli and Enterobacter agglomerans were predominant. Significant correlation were found between the concentration of inhalable dust and inhalable endotoxin as well as between the concentration of airborne gram-negative bacteria and inhalable endotoxin. However these correlation were not very strong. With respect to the characterization of the potential hazard of organic dust exposure, measurements of the concentration of airborne dust or airborne bacteria should not be used for the estimation of the concentration of airborne endotoxin.     

Concentration of airborne endotoxins and airborne bacteria in Chinese rabbit houses

Concentration of airborne endotoxins, airborne aerobic bacteria and airborne aerobic gram-negative bacteria were measured in 3 rabbit houses. Further, the species composition of the airborne gram-negative bacterial flora was investigated. The total amount of airborne endotoxin ranged from 22 to 774 EU/m3 (Endotoxin Units/m3). The number of total airborne aerobic bacteria varied between 780 and 20100 CFU/m3, the number of airborne aerobic gram-negative bacteria between 39 and 1030 CFU/m3. Most gram-negative bacterial isolates belonged to the family Enterobacteriaceae with E. coli as primary species. In two rabbit houses also airborne Pasteurella multocida spp. multocida, the most common respiratory pathogen of rabbits, was isolated.     

Relationship between the concentration of different bioaerosol components and the general hygienic condition in two pig fattening houses

In the study presented here the relationship between the hygienic condition and the concentration of different air contaminants in two pig fattening houses was investigated. Deficiencies in routine cleaning, which were characterized by an increased soiling of animals and stable surfaces with faeces, led to increased concentrations of airborne dust, airborne endotoxins as well as increased numbers of total airborne bacteria and airborne gram-negative bacteria. However these deficiencies were not reflected by the concentration of airborne Clostridium perfringens which were earlier postulated as an indicator of faecal pollution in the air of cattle barns. Furthermore the results of this study were used to discuss advantages and disadvantages of impingement and impaction for the sampling of airborne microorganisms in animal houses.     

The rapid identification of E. coli by the detection of 3 enzymes

232 isolates of gram-negative, oxidase-negative bacteria, isolated from various samples of different animal species, were tested with help of RAPIDEC coli for the production of beta-glucuronidase, beta-galactosidase and indole. The test correctly identified 164 of 175 E. coli strains (sensitivity 93.7%) and correctly indicated that 57 of 57 isolates of the family Enterobacteriaceae (7 Citrobacter sp., 18 Enterobacter sp., 16 Klebsiella sp., 10 Proteus sp., 2 Providencia sp. and 4 Salmonella sp.) were not E. coli (specificity 100%).     

Comparison of bacteriologic culture of blood and necropsy specimens for determining the cause of foal septicemia: 47 cases (1978-1987)

Diagnosis of bacterial septicemia was confirmed by results of bacteriologic culture of antemortem blood samples and/or necropsy specimens obtained from 47 foals up to 8 days old. Gram-negative bacteria were isolated from all 47 foals, and mixed infections with more than one organism were involved in 26 (55%). Escherichia coli, Actinobacillus spp, and Klebsiella pneumoniae were the most frequent isolates, infecting 55, 34, and 23% of foals, respectively. Gram-positive bacteria and anaerobic bacteria were isolated only from foals with mixed infections with gram-negative organisms. Clostridium perfringens was the only anaerobe isolated. In 38 (81%) of 47 foals with confirmed septicemia, blood samples were culture-positive. Thirty-two septicemic foals subsequently died, allowing a comparison to be made between the species of bacteria isolated by culture of blood with those recovered by culture of internal organs at necropsy. Blood failed to yield any gram-negative organisms in 12 (37.5%) of 32 foals from which a gram-negative pathogen was isolated at necropsy. Forty-three percent of the gram-negative bacteria, including 59% of the E coli, and 10% of the gram-positive bacteria found in septicemic foals at necropsy were not detected earlier by results of bacteriologic culture of blood.     

Determination of the inflammatory potential of bioaerosols from a duck-fattening unit by using a limulus amebocyte lysate assay and human whole blood cytokine response

Inhalation of bioaerosols from animal houses can induce acute inflammatory reactions in the respiratory tract. Determination of the concentration of airborne endotoxins is widely used to characterize this risk. In this study, the activity of bioaerosol samples from a duck-fattening unit to induce interleukin-1beta (IL-1beta) in human blood and to react with Limulus Amebocyte Lysate (LAL) was investigated. The activity detected in the whole blood assay correlated well with the endotoxic activity found in the LAL assay (Spearmen's rho = 0.902). However in all samples, the inflammation-inducing potential was overestimated by the LAL assay. It is assumed that this overestimation could be, in part, a result of an overestimation of the inflammatory potential of endotoxins originating from Pseudomonadaceae by the LAL assay. Pseudomonadaceae were regularly isolated from the air of the duck-fattening unit. The results presented here indicate that the whole blood assay can be used besides the LAL assay as an additional method to characterize the inflammation-inducing potential of bioaerosols.     

Antibiotic resistance patterns in fecal bacteria isolated from Christmas shearwater (Puffinus nativitatis) and masked booby (Sula dactylatra) at remote Easter Island

Antibiotic use and its implications have been discussed extensively in the past decades. This situation has global consequences when antibiotic resistance becomes widespread in the intestinal bacterial flora of stationary and migratory birds. This study investigated the incidence of fecal bacteria and general antibiotic resistance, with special focus on extended spectrum beta-lactamase (ESBL) isolates, in two species of seabirds at remote Easter Island. We identified 11 species of bacteria from masked booby (Sula dactylatra) and Christmas shearwater (Puffinus nativitatis); five species of gram-negative bacilli, four species of Streptococcus (Enterococcus), and 2 species of Staphylococcus. In addition, 6 types of bacteria were determined barely to the genus level. General antibiotic susceptibility was measured in the 30 isolated Enterobacteriaceae to 11 antibiotics used in human and veterinary medicine. The 10 isolates that showed a phenotypic ESBL profile were verified by clavulanic acid inhibition in double mixture discs with cefpodoxime, and two ESBL strains were found, one strain in masked booby and one strain in Christmas shearwater. The two bacteria harboring the ESBL type were identified as Serratia odorifera biotype 1, which has zoonotic importance. Despite minimal human presence in the masked booby and Christmas shearwater habitats, and the extreme geographic isolation of Easter Island, we found several multiresistant bacteria and even two isolates with ESBL phenotypes. The finding of ESBLs has animal and public health significance and is of potential concern, especially because the investigation was limited in size and indicated that antibiotic-resistant bacteria now are distributed globally.     

Effect of an electrostatic space charge system on airborne dust and subsequent potential transmission of microorganisms to broiler breeder pullets by airborne dust

High levels of dust and microorganisms are known to be associated with animal confinement rearing facilities. Many of the microorganisms are carried by dust particles, thus providing an excellent vector for horizontal disease transmission between birds. Two environmentally controlled rooms containing female broiler breeder pullets (n = 300) were used to evaluate the effectiveness of an electrostatic space charge system (ESCS) in reducing airborne dust and gram-negative bacteria levels over an 8-wk period (starting when the birds were 10 wk old). The ESCS was used to evaluate the effectiveness of reducing airborne microorganism levels by charging airborne dust particles and causing the particles to be attracted to grounded surfaces (i.e., walls, floor, equipment). The use of the ESCS resulted in a 64% mean reduction in gram-negative bacteria. Airborne dust levels were reduced an average of 37% over a 1-wk period in the experimental room compared with the control room on the basis of samples taken every 10 min. The reductions of airborne dust and bacteria in this study are comparable with earlier results obtained with the ESCS in commercial hatching cabinets and experimental caged layer rooms, suggesting the system could also be applied to other types of enclosed animal housing.     

Relationship between bacterial translocation and isolation of enteric bacteria from extraintestinal organs in slaughtered pigs

Enteric bacteria, especially Escherichia coli, have been isolated from porcine livers affected with ascariasis. We hypothesized that reason for this bacterial isolation was due to bacterial translocation (BT). In order to clarify the association between ascariasis and isolation of Enterobacteriaceae in the livers,12 pigs with ascariasis (ascariasis group), 12 pigs without ascariasis (non-ascariasis A group) were used. Jejunum, ileum, cecum, colon, livers, mesenteric lymph nodes (MLN), and portal blood were obtained from these pigs. Furthermore, in order to confirm the presence of BT in pigs, the samples mentioned above as well as spleens were obtained from 11 pigs without ascariasis (non-ascariasis B group) and 6 specific pathogen free (SPF) pigs without ascariasis (non-ascariasis SPF group). In the first experiment, the gram-negative bacteria were isolated from livers (66.7%), MLN (91.7%), and portal blood (55.6%) regardless the presence of ascariasis. In the second experiment, isolation rates of gram-negative and -positive bacteria were 52.9 and 66.7% for livers, 52.9 and 80% for MLN, 11.8 and 26.7% for spleens, and 40 and 20% for portal blood of the pigs examined, respectively. E. coli and Staphylococcus were the predominant isolates from these pigs. A large number of antigens immunodetected by E. coli polyclonal antibody were found in the damaged cecal mucosa. These findings present evidence that BT is generally observed in slaughtered pigs regardless the presence of ascariasis. This has challenged our notion that extraintestinal organs of pigs are usually maintained as sterile.     

规模化驴场空气中细菌数量与种类的调查与分析

[目的]分析规模化驴场空气环境中细菌数量与种类,指导驴场防御和控制细菌性疾病的方向。[方法]从不同开放模式的驴舍用自然沉降法收集其内部空气中细菌样本及场区周边不同距离的空气细菌样本,使用平皿法对采集的细菌进行培养、计数、鉴别。[结果]驴场内空气中细菌总数的范围8.39×10~3~3.43×10~4CFU/m~3,保育驴舍（封闭式驴舍）的细菌总数高于分娩驴舍（半开放式驴舍）及种公驴舍（开放式驴舍）,其中种公驴舍细菌总数最低。驴场对周边空气环境的污染范围为200 m。主要优势菌落是葡萄球菌、链球菌、大肠杆菌、绿脓杆菌等。[结论]规模化驴场空气环境中的细菌种类繁多,驴舍内细菌数量与其开放方式有关,且细菌数量随距驴场距离的增加而减少。     

Aerobic bacterial flora of nesting green turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica.

Bacteriological examination of 70 nesting green turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica was performed to investigate nasal and cloacal aerobic bacteria. A total of 325 bacterial isolates were obtained, including 10 Gram-negative and three Gram-positive genera. Two hundred thirty-nine were Gram-negative and 86 were Gram-positive isolates. Klebsiella pneumoniae was the most common microbe identified in turtle samples: 27/70 (38.5%) in cloacal, and 33/70 (47.1%) in nasal samples. The Enterobacteriaceae family, including Enterobacter agglomerans, E. cloacae, Escherichia coli, Klebsiella oxytoca, K. pneumoniae, and Serratia marcescens, was the largest Gram-negative group of bacteria recovered and comprised 127 of 239 (53.1%) of the Gram-negative isolates. Staphylococcus species was the largest Gram-positive bacteria group, including S. aureus, S. cromogenes, S. epidermis, and S. intermedius, and made up 63 of 86 (73.2%) of the Gram-positive isolates recovered. The results of this study demonstrate that the aerobic bacterial flora of nesting green turtles at Tortuguero National Park is composed of a very wide spectrum of bacteria, including several potential pathogens.     

A survey of aerobic bacteria and fungi in the feces of healthy psittacine birds

Fecal samples from 61 clinically healthy psittacine birds of a wide variety of species were cultured for bacteria and fungi. The most common bacterial isolates were gram-positive bacilli, which were recovered from 60 of the 61 birds. These organisms included Lactobacillus, Bacillus, Corynebacterium, and Streptomyces. Gram-positive cocci, cultured from the feces of 21 of the birds, included Staphylococcus epidermidis, Streptococcus spp., Aerococcus spp., and Micrococcus spp. Only 6 of the 61 psittaciformes yielded gram-negative bacteria, with Escherichia coli being the most frequent isolate. Gram-negative bacilli were recovered from 4 of the 31 privately owned birds and 2 of the 30 petshop birds sampled. In addition to the bacteria, Candida albicans, Cryptococcus laurentii, and Aspergillus sp. were isolated from 13 fecal cultures. Candida albicans was isolated exclusively from 5 petshop birds. The number of birds yielding Corynebacterium and gram-negative bacteria increased with age, whereas the number of birds yielding lactobacilli and yeasts decreased with age. The organisms isolated and their significance as potential pathogens in psittacine birds are discussed.     

Blood culture of the canine patient

Blood for bacteriologic culture was obtained from 581 sick dogs. Of these, 134 (23%) were considered to have bacteremia. The conditions most frequently associated with bacteremia were malignant neoplasms and infections of the skeletal, cardiovascular, and urogenital systems. The most frequently isolated bacteria were members of the family Enterobacteriaceae and coagulase-positive staphylococci, in sum accounting for more than 50% of the 150 isolates. Most of the dogs with bacteremia had high proportions of immature neutrophils, segmented neutrophils, and monocytes in blood. Dogs with bacteremia and osteomyelitis due to staphylococci had normal hemograms. Blood from dogs with bacteremia due to gram-negative bacteria was more likely to have a high proportion of immature and segmented neutrophil leukocytes than was blood from dogs with bacteremia due to a gram-positive species. Toxic neutrophils were observed more often in blood obtained from patients with bacteremia due to gram-negative bacteria. The development of fever correlated with the bacteremic state regardless of the species of bacteria in the blood.     

Changes in bacterial and fungal ocular flora of clinically normal horses following experimental application of topical antimicrobial or antimicrobial-corticosteroid ophthalmic preparations

OBJECTIVE: To determine effects of topical antimicrobial and antimicrobial-corticosteroid preparations on the ocular flora of horses. animals: 40 horses. PROCEDURE: One eye was treated 3 times daily for 2 weeks with one of the following ointments: (1) neomycin-bacitracin-polymyxin B, (2) 0.6% prednisolone-0.3% gentamicin, (3) neomycin-polymyxin B-0.05% dexamethasone, or (4) treated (artificial tears) control. Contralateral eyes of treated control eyes served as untreated control eyes. Corneal and conjunctival specimens for bacterial and fungal cultures were collected prior to initiation of treatment, after 1 and 2 weeks of treatment, and 2 weeks after concluding treatment. Changes in culture growth quantity scores of bacterial and fungal species were analyzed. RESULTS: The most common species before treatment were the following: gram-positive bacteria included Streptomyces spp (66%), Staphylococcus spp (46%), Bacillus spp (32%), and Streptococcus spp (32%); gram-negative bacteria included Moraxella spp (28%), Escherichia coli (24%), Acinetobacter spp (18%), and Enterobacter spp (14%); and fungi included Aspergillus nidulans (56%), Cladosporium spp (32%), and Aspergillus fumigatus (22%). In all groups, the percentage of positive bacterial culture results, growth quantity score of gram-positive bacteria, and number of bacterial species isolated decreased at week 1 and increased at week 2, whereas growth quantity score of gram-negative bacteria decreased throughout treatment. Differences were not significant among groups. Fungal growth quantity score decreased during treatment in all groups. Repopulation of bacterial and fungal species occurred. CONCLUSIONS AND CLINICAL RELEVANCE: All interventions decreased the number of microorganisms. Repopulation of normal flora occurred during and after treatment.     

Rates of resistance of mastitis pathogens from cows in Switzerland

1215 strains of bacteria isolated from cows suffering from acute or chronic clinic mastitis were tested in the antibiogram according to the Kirby-Bauer method. The germ spectrum included: 304 DNase-positive strains of Staphylococci 304 DNase-negative strains of Staphylococci 304 CAMP-negative strains of Streptococci 303 Strains of Enterobacteriaceae The antibiotics selected were Penicillin, Cloxacillin, Neomycin und Gentamicin, then the combinations Penicillin/Neomycin, Cloxacillin/Gentamicin and Nafcillin/Penicillin/Dihydrostreptomycin. Gentamicin showed excellent action against Staphylococci and Enterobacteriaceae. Further on, the present investigations show, that the combination Cloxacillin/Gentamicin is fully effective in the gram-positive spectrum (against Streptococci and Staphylococci), as in the gram-negative spectrum (against E. coli).     

Prevalence of gastrointestinal bacterial pathogens in a population of zoo animals

Faecal prevalence of gastrointestinal bacterial pathogens, including Campylobacter, Escherichia coli O157:H7, Salmonella, Shigella, Yersinia, as well as Arcobacter, were examined in 317 faecal specimens from 44 animal species in Belfast Zoological Gardens, during July-September 2006. Thermophilic campylobacters including Campylobacter jejuni, Campylobacter coli and Campylobacter lari, were the most frequently isolated pathogens, where members of this genus were isolated from 11 animal species (11 of 44; 25%). Yersinia spp. were isolated from seven animal species (seven of 44; 15.9%) and included, Yersinia enterocolitica (five of seven isolates; 71.4%) and one isolate each of Yersinia frederiksenii and Yersinia kristensenii. Only one isolate of Salmonella was obtained throughout the entire study, which was an isolate of Salmonella dublin (O 1,9,12: H g, p), originating from tiger faeces after enrichment. None of the animal species found in public contact areas of the zoo were positive for any gastrointestinal bacterial pathogens. Also, water from the lake in the centre of the grounds, was examined for the same bacterial pathogens and was found to contain C. jejuni. This study is the first report on the isolation of a number of important bacterial pathogens from a variety of novel host species, C. jejuni from the red kangaroo (Macropus rufus), C. lari from a maned wolf (Chrysocyon brachyurus), Y. kristensenii from a vicugna (Vicugna vicugna) and Y. enterocolitica from a maned wolf and red panda (Ailurus fulgens). In conclusion, this study demonstrated that the faeces of animals in public contact areas of the zoo were not positive for the bacterial gastrointestinal pathogens examined. This is reassuring for the public health of visitors, particularly children, who enjoy this educational and recreational resource.     

山西省东南部羊舍气载真菌浓度变化及空气动力学特征

试验研究了山西省东南部羊舍气载真菌浓度变化规律和真菌气溶胶的空气动力学特征,以期为羊场的环境控制提供依据。应用Andersen-6级空气微生物采样器,以孟加拉红培养基为采样介质,于春、夏、秋、冬分别采集了山西省东南部3个羊场羊舍的真菌气溶胶,分析其气载真菌浓度和真菌气溶胶的粒径特点。结果表明,羊舍气载真菌一年中以秋季浓度最高,显著高于其他季节（P<0.05）,且秋季一天上午、中午、下午3个时间段中,浓度差异显著（P<0.05）;羊舍真菌气溶胶粒子4个季节在采样器上的分布基本相同,高峰出现在第Ⅳ级,主要分布在Ⅲ~Ⅴ级,占各级总数的72.66%~83.87%,可进入人和动物的肺泡;羊舍真菌气溶胶粒子计数中值直径（CMD）为1.3~2.9 μm,粒径分布的离散度（GSD）为1.6~2.7 μm;夏季CMD显著低于其他季节（P<0.05）。综合以上结果,羊舍气载真菌浓度与季节密切相关,80%左右气溶胶粒子可进入人和动物肺泡,且CMD小于其他动物圈舍,潜在危害较大。     

Gram-negative bacterial infections of the mammary gland in cows

Naturally acquired gram-negative bacterial intramammary infections (n = 160) were studied in 99 cows over a 2-year period. Escherichia coli, Klebsiella spp, Serratia spp, Enterobacter spp, and unidentified gram-negative bacteria were isolated from 28.8, 39.4, 9.4, 5.0, and 11.2%, respectively, of infected mammary glands. A majority (61%) of intramammary infections were first detected during the nonlactating period. Gram-negative bacteria isolated during the first half of the nonlactating period were predominantly Klebsiella spp, Serratia spp, and Enterobacter spp. Onset of E coli intramammary infections was more prevalent during the second half of the nonlactating period and during the first 7 days of lactation. The majority (59%) of infections were less than 28 days in duration, but Klebsiella spp and Serratia spp infections were of significantly (P less than 0.05) greater duration than infections with E coli. The greatest percentage (47%) of gram-negative bacterial intramammary infections were first detected during the summer.     

一例鸡大肠杆菌病的病原分离鉴定

为确诊某养鸡场发病的原因,采集临床病死鸡的肝脏、脾脏进行细菌分离培养,并通过细菌形态学观察、生化试验、分子生物学鉴定和药物敏感性试验.结果:分离细菌为革兰氏阴性杆菌,菌落形态和生化鉴定特征与大肠杆菌相符;16S rDNA PCR扩增及基因同源性分析确定为大肠杆菌;菌株对安普霉素、泰妙菌素、多西环素、硫酸粘菌素较敏感,对替米考星、泰万菌素、磺胺间甲氧嘧啶、泰乐菌素、阿莫西林存在耐药性.