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PubMedDate not supplied

Occurrence of acute infectious bursal disease with high mortality in Japan and pathogenicity of field isolates in specific-pathogen-free chickens.

Highly virulent infectious bursal disease virus (IBDV) was isolated from field cases, and the pathogenicity of the isolates was examined in specific-pathogen-free chickens. Chickens inoculated with the isolates developed severe clinical disease with a high mortality rate. Histopathologically, infectious bursal disease was characterized by bursal and thymic necrosis, aplastic anemia, acute hepatitis with fatty change, and systemic inflammatory response. In addition to functional abnormalities in the liver, a hypoxic state was induced by aplastic anemia and severe inflammation in the pulmonary air capillary walls. These pathological changes appeared to be closely related to the cause of death.

Animals↗
PubMed1989

Physiological characteristics of environmental isolates of pathogenic dematiaceous fungi.

A total of 39 environmental isolates of pathogenic dematiaceous fungi (Fonsecaea pedrosoi: 14 isolates, Phialophora verrucosa: 6, Cladosporium carrionii: 9, Exophiala jeanselmei: 2, Ramichloridium subulatum: 6, Cladosporium tenuissimum: 1 and Phaeoisaria clematidis: 1) were evaluated for their various physiological characteristics including the ability to produce extracellular enzymes. Significant physiological characteristics included the ability of isolates of all the species except C. tenuissimum to decompose tyrosine, lyse human red blood cells, conversion of R. subulatum from filamentous to yeast form when cultured on Czapek-Dox agar and also on blood agar and the growth of C. tenuissimum on Sabouraud dextrose agar incorporating 3.6 M NaCl. Isolates of all the species except those of C. carrionii produced lipase, while only the isolates of P. verrucosa, E. jeanselmei and Ph. clematidis were positive for phospholipase.

Mitosporic Fungi↗
PubMed1993

Structure and copy number analyses of pap-, sfa-, and afa-related gene clusters in F165-positive bovine and porcine Escherichia coli isolates.

Pathogenic F165-positive Escherichia coli isolates of porcine and bovine origin possess gene clusters related to extraintestinal E. coli fimbrial operons pap, sfa, and afaI. Probes from different segments of the pap, sfa, and afaI operons were used in Southern hybridization to analyze 18 F165-positive, mannose-resistant hemagglutinating E. coli isolates possessing pap- and sfa-, pap- and afa-, or pap-related sequences. Only single copies of the pap-, sfa-, or afa-related sequences were found among the isolates, and the position of each sequence with respect to those of adjacent sequences was variable. Expression of the P and F adhesins individually or concurrently was associated with the presence of a single copy of pap-related sequences. Gene clusters related to pap were structurally similar to the pap operon in certain isolates or the prs operon in others. sfa-related sequences showed few internal structural polymorphisms and were structurally similar to the foc rather than the sfa operon. afa-related sequences showed many internal structural polymorphisms compared with the afa-related sequences from prototype strain KS52. These results demonstrate that the pap- and sfa-related sequences in F165-positive isolates are closely related to the prototype pap operon and foc operon of the P family and Sfa family, respectively. afa-related sequences, on the other hand, display heterogeneity and differ from the prototype afaI operon.

Adhesins, Escherichia coli↗
PubMed1977

Colonization of the botanical environment by Klebsiella isolates of pathogenic origin.

Growth, survival, and pathogenicity of Klebsiella growing in and on environmental foci were examined. Total coliforms present in raw wastes from pulp mills were in excess of 10(5)/ml, and 60 to 80% were Klebsiella. Fecal coliform counts ranged from 10(1) to 10(5)/ml. Klebsiella isolates from industrial effluents and a variety of human and bovine mastitis origins multiplied in pulp waste and commonly exceeded 10(6) cells per ml. Pathogenic isolates also multiplied in dilute aqueous extracts of sawdust to comparable levels. Klebsiella strains from vegetable surfaces and human infections grew rapidly on the surfaces of potatoes and lettuce and exceeded 10(3) organisms per g of surface peel and leaf after a 24h incubation at room temperature. After 7 weeks on potatoes stored at 5 degrees C, some 10 to 30% of the day 1 Klebsiella counts were recoverable. Three Klebsiella isolates of pathogenic origin were passed 45 times through sterile pulp effluent (270 generations), and mean lethal dose levels in mice were periodically monitored. In two instances, a significant decrease in virulence was noted after 15 to 26 passes (90 to 156 generations). The third culture, of bovine mastitis origin, retained its original mean lethal dose value. Botanical milieu provided suitable habitats for the multiplication and colonization of Klebsiella isolates of disease origins in the same manner as indigenous isolates. Aquatic environments polluted with botanical material served as potential reservoirs for perpetuating the growth and spread of opportunistic Klebsiella pathogens that may ultimately colonize animals, humans, and aquatic organisms.

Animals↗
PubMed1979

Isolation of pathogenic treponemes from hare.

A presumably new species of pathogenic treponemes was isolated from a lesion on the male organs of hare (Lepus sp.) and the scrotum of a rabbit (Oryctolagus sp.) was infected with this treponeme. Lesion developed on the scrotum after a 110-day incubation.

Animals↗
PubMedDate not supplied

Comparative in vitro activity of cefodizime and other antibiotics against pathogens recently isolated in Italy.

In the present study we tested the susceptibility to cefodizime on 1,985 selected nosocomial pathogens isolated in five laboratories. Moreover, we evaluated the epidemiology of the resistance of the tested strains to cefodizime and to other antibiotics clinically available in Italy. The susceptibility to cefodizime was determined with both MIC (microdilution method) and the agar diffusion method (Kirby-Bauer). The Kirby-Bauer method was used to compare the antibiotics. Cefodizime was equivalent in activity to ceftazidime and ceftriaxone and was more active than piperacillin and amoxicillin + clavulanic acid. The activity of gentamicin (where tested) was generally comparable to that of cefodizime; ciprofloxacin had lower percentages of resistance against some species of Enterobacteriaceae and staphylococci.

Bacteria↗
PubMed2004

Isolation of pathogenic Listeria monocytogenes and detection of antibodies against phosphatidylinositol-specific phospholipase C in buffaloes.

The isolation of pathogenic Listeria spp. in bacteriological samples, and anti-phosphatidylinositol-specific phospholipase C (anti-PIPLC) antibodies in sera of buffaloes were studied. Isolation of the pathogen was attempted from the samples by selective enrichment in University of Vermont Medium and plating onto Dominguez-Rodriguez isolation agar. Pathogenicity of the isolates was tested by Christie, Atkins, Munch Petersen test and mice incoulation test. Listeria spp. and L. monocytogenes were isolated from 8.8 and 2.4%, and 4.8 and 1.6% of 125 each meat and blood samples, respectively. Out of the 125 samples each of feacal, nasal and vaginal swabs from buffaloes 8 and 4%, 13.6 and 2.4%, and 6.4 and 2.4% were positive for Listeria spp. and L. monocytogenes, respectively. L. ivanovii was confirmed from 0.8% vaginal sample. A total of 125 serum samples were tested by phosphatidylinositol-specific phospholipase C (PIPLC) based indirect ELISA of which 4.0% turned out to be seropositive.

Animals↗
PubMed1998

Quantitative relationships among thaxtomin A production, potato scab severity, and fatty acid composition in Streptomyces.

Thaxtomin A production in culture, potato common scab severity (percentage of tuber surface infected or number of lesions per tuber), and fatty acid profiles were determined for 78 Streptomyces isolates. Only pathogenic Streptomyces spp. (n = 17) produced thaxtomin A in culture. Thaxtomin A production in culture (microgram/mL) was significantly positively correlated with the percentage of tuber surface infected (R = 0.60; p = 0.017) but not with the number of lesions per tuber (R = 0.37; p = 0.17). An increase of 1 microgram/mL in thaxtomin A production corresponded to an 11% increase in disease severity (percentage of tuber surface infected). The data indicate that quantitative information on the ability of a particular pathogen isolate or population to produce thaxtomin A may be critical to understanding and predicting the disease potential of that population. Using cluster analysis of fatty acid data, 94% of 67 unknown field isolates grouped with other field isolates having the same pathogenicity (plus or minus).

Bacterial Toxins↗
PubMedDate not supplied

Adjuvant fosfomycin medication in chronic osteomyelitis.

The therapeutic effectiveness of adjuvant therapy with fosfomycin was studied in a prospective clinical trial of 60 patients suffering from chronic post-traumatic osteomyelitis. The patients were aged between 17 and 78 years (mean 37.4 years). The chronic osteomyelitis was predominantly located in the tibia (43 patients) and in the femur (13 patients). Most of the pathogens isolated were Staphylococcus aureus (42%), coagulase-negative staphylococci (19%), Pseudomonas aeruginosa (12%), streptococci (7%) and enterococci (5%). The pathogens isolated from the osteomyelitic foci were sensitive to fosfomycin. Fosfomycin concentrations in bone samples were determined in 19 patients. In the group of patients receiving initially 5 g fosfomycin, bone concentrations ranged between 119.4 and 451.2 mg/l of interstitial fluid. In the group of patients receiving initially 10 g fosfomycin, bone concentrations ranged between 117.1 and 3684.2 mg/l of interstitial fluid. The mean MIC90 values of the isolated pathogens ranged between 2 and 64 mg/l (S. aureus and Escherichia coli 2 mg/l, Proteus vulgaris 8 mg/l, streptococci groups A and B 32 mg/l and coagulase-negative staphylococci, enterococci and P. aeruginosa 64 mg/l). The outcome of treatment was assessed after a minimum of seven and a maximum of 53 months (mean 37 months). The results were: very good 54.7%, good 3.8%, satisfactory 15.1% and unsatisfactory 26.4%.

Adolescent↗
PubMed1996

Colonization and infection with Moraxella catarrhalis in childhood.

In a prospective clinical study, rates of isolation of Moraxella catarrhalis in nasopharyngeal aspirates from 122 children with respiratory tract infection and 72 healthy controls were compared. In the patient group, Moraxella catarrhalis and Streptococcus pneumoniae were the most frequently isolated pathogens (38% and 42%, respectively). Monocultures of each pathogen were equally distributed in patients and controls (41% and 42%), whereas mixed infections were found more frequently in the patient group (42% vs 14%; normal flora, 17% vs 44%). Moraxella catarrhalis appears to be a relevant respiratory pathogen. The isolation of two or more pathogens in nasopharyngeal aspirates seems to be as indicative of relevant infection as is monoculture.

Acute Disease↗
PubMed2003

[Evaluation of drug sensitivity of the microorganisms isolated from chronic sinusitis treated by beta lactam antibiotics].

The drug sensitiveness to beta-lactam antibiotics of the bacterial flora, taken by sinus puncture from 115 patients with unior bilateral acute exacerbation of chronic maxillary sinusitis was analysed. About 90% of the isolated pathogens, as well as in subgroup treated with amoxicillin with potassium clavulanate and in subgroup treated with cefuroxime axetil showed antibiotic sensitivity. Among isolated pathogens before the treatment, 4 (9.5%) were resistant to the amoxicillin with potassium clavulanate disks in subgroup A and 3 (7.3%) to the cefuroxime axetil in subgroup B. There was only one pathogen isolated in the control evaluation in both group after the treatment.

Amoxicillin-Potassium Clavulanate Combination↗
PubMedDate not supplied

Highly pathogenic virus recovered from chickens infected with mildly pathogenic 1986 isolates of H5N2 avian influenza virus.

A combination of in vitro and in vivo selection procedures was used to examine the possibility that certain mildly pathogenic field isolates of avian influenza (AI) virus may contain minority subpopulations of highly pathogenic virus. Two mildly pathogenic H5N2 isolates, A/chicken/New Jersey/12508/86 (NJ12508) and A/chicken/Florida/27716/86 (FL27716), recovered from chickens epidemiologically associated with urban live-bird markets, were cloned in trypsin-free chicken embryo fibroblast cultures. Selected clones were inoculated intranasally and intratracheally (IN/IT) into specific-pathogen-free laying hens, and virus reisolated from the hens that died was serially passed in hens by IN/IT inoculation. Several highly pathogenic reisolates were recovered from hens infected with the cloned NJ12508 or FL27716 virus. A highly pathogenic NJ12508 reisolate killed 19 of 24 IN/IT-inoculated hens, and a FL27716 reisolate killed all 24 inoculated hens; signs and lesions were typical of fowl plague. In contrast, uncloned NJ12508 stock virus killed 1 of 24 hens and FL27716 stock virus killed 4 of 24 hens, and neither produced the complete spectrum of lesions associated with fowl plague. Recovery of highly pathogenic viruses from these isolates demonstrates the coexistence of pathogenically distinct subpopulations of virus. Competition for dominance among such subpopulations could explain the variable pathogenicity of some AI viruses.

Animals↗
PubMed2001

Characteristics of a recent isolate of Sarcocystis neurona (SN7) from a horse and loss of pathogenicity of isolates SN6 and SN7 by passages in cell culture.

An isolate of Sarcocystis neurona (SN7) was obtained from the spinal cord of a horse with neurologic signs. The parasite was isolated in cultures of bovine monocytes and equine spleen cells. The organism divided by endopolygeny and completed at least one asexual cycle in cell cultures in 3 days. The parasite was maintained by subpassages in bovine monocytes for 10 months when it was found to be non-pathogenic to gamma interferon knockout (KO) mice. Revival of a low passage (10th passage) of the initial isolate stored in liquid nitrogen for 18 months retained its pathogenicity for KO mice. Merozoites (10(6)) of the late passage (22nd passage) were infective to only one of four KO mice inoculated. Similar results were obtained with SN6 isolate of S. neurona. No differences were found in Western blot patterns using antigens from the low and high passage merozoites of the SN7 and SN6 isolates. These results suggest that prolonged passage in cell culture may affect the pathogenicity of some isolates of S. neurona.

Animals↗
PubMed1985

Use of the mushroom tissue block rapid pitting test to detect brown blotch pathogens.

Isolates of an Arthrobacter species known to produce a positive host pathogenicity test were evaluated by the mushroom tissue block rapid pitting test. All 11 isolates of the Arthrobacter species yielded a positive test response. The time required for a positive test was the same for Pseudomonas tolaasi and the Arthrobacter species.

Journal Article↗
PubMed1992

Comparison of standard and quantitative blood cultures in the evaluation of children with suspected central venous line sepsis.

We reviewed our experience with paired quantitative and standard blood cultures in the evaluation of children with suspected central-line sepsis with the hypothesis that by employing both systems we would increase our yield of pathogenic isolates. A total of 913 paired cultures were reviewed, representing 267 pathogenic isolates and 58 individual episodes of sepsis. The isolates were analyzed for recovery rates for each system and by combining both systems. The Isolator system proved to be equal to the BACTEC system for the recovery of all groups of pathogenic isolates. The combined use of both the quantitative and the standard culture systems demonstrated a statistically significant advantage (p less than 0.001) for the recovery of pathogens as compared with either system alone. The use of either system alone would have missed 15% of the total pathogenic isolates. Quantitative colony counts were helpful in identifying the line as the source of infection in 35 to 58 episodes of sepsis and were often beneficial in the clinical management central venous line infection. We recommend the use of the Isolator 1.5 ml combined with a conventional broth-bottle system in selected pediatric patients to enhance the recovery of pathogenic organisms.

Bacteremia↗
PubMedDate not supplied

Variation in virological parameters and antibody responses in macaques after atraumatic vaginal exposure to a pathogenic primary isolate of SIVmac251.

We developed an animal model for the male-to-female transmission of human immunodeficiency virus, consisting of an atraumatic vaginal application of simian immunodeficiency virus onto the intact vaginal mucosa of cynomolgus macaques. Different doses of a pathogenic isolate of SIVmac251, with or without seminal plasma, were infused into the vaginas of female macaques. Infection of macaques could be achieved after a single exposure to the virus. Two patterns of infection were underscored with no relation to the virus dose inoculated: in 50% of the monkeys, SIV was persistently recovered and a strong antibody response to SIV was evidenced in blood and vaginal secretions. In the other infected animals, SIV infection was only transiently evidenced and a weak systemic antibody response was detected. It appeared that the presence of seminal plasma may be implicated in this variability only when low doses of virus are inoculated. Sequence analysis of the env gene of SIV revealed that most of the persistently viraemic animals were infected with a viral variant different from that of transiently viraemic macaques.

Amino Acid Sequence↗
PubMed1989

The efficiency of 1 M NH4Cl and 2 M NaCl for the isolation of pathogenic Nocardia from soil.

The present paper reports an improvement to the classical method of the paraffin bait, by the usage of 1 M NH4Cl or 2 M NaCl to eliminate contaminant microflora of soil. The purpose is to introduce a change in the paraffin bait method in order to reduce time required to isolate pathogenic strains of Nocardia from their natural sources. For this study three main criteria were used: a) Determination of the inhibitory effect of different concentrations of salts on soil microflora; b) The tolerance of Nocardia brasiliensis, Nocardia asteroides and Nocardia caviae (Nocardia otitidis caviarum) strains to these chemical inhibitors; c) Determination of the efficiency of salts in the isolation of Nocardia from soil when strains are grown on paraffin baits.

Ammonium Chloride↗
PubMed2001

The microbiology of chronic rhinosinusitis: results of a community surveillance study.

In view of the rapidly changing patterns of antibiotic resistance, community surveillance studies are providing important information to help guide practitioners in making their choice of antibiotics. For this community surveillance study, we performed a retrospective chart review of nasal and sinus culture data obtained from 83 patients with typical symptoms of chronic rhinosinusitis who visited a community otolaryngologist in Rochester, New York. Pathogens were isolated in 59 of these patients (71%). The most common were coagulase-negative staphylococci (31% of isolates). Among the other isolated pathogens were Hemophilus influenzae (25%), Streptococcus pneumoniae (12%), Moraxella catarrhalis (10%), Pseudomonas aeruginosa (7%), alpha-hemolytic streptococci (5%), and Staphylococcus aureus (3%). Approximately 39% of the coagulase-negative staphylococci isolates were resistant to penicillin. Some 20% of the H influenzae isolates were beta-lactamase-positive, and 14% of all isolates were resistant to multiple antibiotics. Approximately 12% of the 83 patients cultured positive for multiple organisms. Our findings provide important surveillance information about the resistance patterns of pathogens in our area. Although the prevalence of beta-lactamase-positive H influenzae that we observed was consistent with those of other reports, we found a lower prevalence of polymicrobial flora. Our findings suggest that culture- and sensitivity-directed therapy should be effective in the treatment of chronic rhinosinusitis.

Bacterial Infections↗