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At least 217 records · Page 12Linked to original sources
PubMed2000

Characterization of hemolysin of Moraxella bovis using a hemolysis-neutralizing monoclonal antibody.

A concentrated bacterial culture supernatant from the hemolytic Moraxella bovis strain UQV 148NF was used to immunize mice and generate monoclonal antibodies (MAbs). One, MAb G3/D7, neutralized the hemolytic activity of M. bovis and recognized a 94-kDa protein by Western blot analysis in hemolytic M. bovis strains representing each of the different fimbrial serogroups. Exposure of corneal epithelial cells to M. bovis concentrated culture supernatants demonstrated a role for an exotoxin in the pathogenesis of infectious bovine keratoconjunctivitis, while neutralization of hemolytic and cytotoxic activities by MAb G3/D7 implies that these activities are related or have common epitopes. The action of M. bovis hemolysin was further characterized in sheep erythrocyte preparations with a binding step and Ca(2+) required for lysis to proceed, similar to the RTX family of bacterial exotoxins. Neutralization of lytic activity in vitro is evidence for the presence of M. bovis antigens, which may be capable of protecting cattle from the development of infectious bovine keratoconjunctivitis.

Animals↗
PubMed1994

Reproduction of bovine keratoconjunctivitis with a purified haemolytic and cytotoxic fraction of Moraxella bovis.

Evidence that the beta-haemolysin produced in vitro by Moraxella bovis is an important virulence determinant in vivo was strengthened by studies using a haemolytic preparation of greater purity than previously available. A concentrated haemolytic fraction containing outer-membrane bound vesicles was separated from the cell-free filtrate of a bacterial culture using a process comprising tangential flow ultrafiltration, ion-exchange and gel-filtration high-performance liquid chromatography and centrifugal-driven filtration. The cytotoxicity of haemolytic fractions for calf-corneal epithelial cells in vitro was investigated at progressive stages of this attempted haemolysin purification procedure and the results demonstrated a positive correlation for the levels of haemolytic and cytotoxic activity throughout. Further support for the role of the haemolysin was obtained in vivo following the intra-corneal injection of calves with a crude or a purified haemolytic fraction. The ocular damage caused by both preparations, together with the healing processes and microscopic pathology of the experimentally induced damage closely resembled published descriptions of naturally occurring infectious bovine keratoconjunctivitis. No effect was obtained in vitro or in vivo from equivalent fractions prepared from a non-haemolytic strain of M. bovis.

Animals↗
PubMed1995

Partial characterization of a Moraxella bovis cytolysin.

Moraxella bovis (M. bovis) is the etiologic agent of infectious bovine keratoconjunctivitis and M. bovis hemolysin is believed to be an important virulence factor. Two strains of M. bovis were compared, Epp 63(300) (Epp), a known virulent and hemolytic strain, and IBH 63 (IBH), a known avirulent and nonhemolytic strain. Sterile 10-fold (10x) supernatant concentrates were obtained from cultures grown in TSB broth with 10 mM CaCl2. Supernatant hemolysin titers for Epp, were 1:1024 and 1:8192 for unconcentrated (1x) and 10x, respectively. Supernatant cytotoxin titers to bovine mononuclear cells were 1:32 and 1:128 for 1x and 10x, respectively, for Epp. Cytolytic (hemolytic and cytotoxic) activities declined 10-fold but were still measurable for > 1 wk at 4 degrees C. Both activities were inactivated by trypsin and by heating at 56 degrees C for 20 min. A cytotoxic effect was observed on cultured bovine and ovine corneal epithelial cells with Epp. All cytolytic effects were neutralized with antiserum to 10x Epp. No cytolytic activities were detected for 10x IBH. SDS-PAGE electrophoresis and related immunoblots indicate a high molecular weight protein at 110 kDa for the 10x Epp preparation when stained with silver or probed with monoclonal antibodies to the E. coli alpha hemolysin. No 110 kDa band is observed for 10x IBH. These data suggest that hemolytic and cytotoxic activities are important in the pathogenesis of infectious bovine keratoconjunctivitis and identify the protein as a possible RTX related toxin of 110 kDa. Stability of the M. bovis cytolysin for > 1 week should allow further characterization and purification of the protein.

Animals↗
PubMed1996

Mycoplasmas associated with bovine conjunctivitis and keratoconjunctivitis.

In two separate herds of fattening calves a sudden-onset outbreak of ocular disease with profuse lacrimation occurred. The disease resembled the early stage of infectious bovine keratoconjunctivitis but after a few days the clinical signs of bronchopneumonia appeared. From conjunctival swabs Mycoplasma (M.) bovigenitalium, M. bovirhinis and infectious bovine rhinotracheitis (IBR) virus were isolated. Moraxella bovis infection was not established. In one of the herds M. bovigenitalium was also found in the pneumonic lungs of dead calves. In one herd M. bovoculi was isolated from a cow with chronic keratoconjunctivitis, housed together with affected calves. Mycoplasmas were not isolated from ocular swabs of six bulls originating from a Reproductive Centre with temporary occurrence of unilateral serous conjunctivitis resistant to antibiotic therapy.

Animals↗
PubMed2006

[Conjugal leprosy].

OBJECTIVES: Determining the occurrence of leprosy amongst couples and establishing the type of leprosy in index and secondary cases. METHODS: The characteristics of leprosy were studied between 1980 and 2000 in Atlántico Department located on the Colombian Caribbean Coast. Clinical histories of patients registered in the Leprosy Control Programme were reviewed. Clinical exams were performed and personal interviews carried out with couples suffering from leprosy. RESULTS: Twenty-six married couples were found to be suffering from leprosy, representing 5.4% of leprosy cases detected during the study period. They were aged from 20 to 89. 65.4% of the index cases were men and 22 (84.6%) were multibacillary, lepromatous cases; two had indeterminate leprosy and two were suffering from tuberculoid leprosy. Sixty-one percent of the secondary cases were paucibacillary patients, 42% of them being tuberculoid. No paucibacillary cases were associated with multibacillary leprosy in the couples. Only two couples had consanguinity. None of the couples had had leprosy at the time of being married. The time between leprosy being detected in index cases and the disease being detected in secondary patients varied from 5 to 40 years. Disabilities were more common in the feet and to a higher degree in lepromatous index cases who had had the disease for a longer time than the secondary cases because these were more frequently paucibacillary patients who had a disease having shorter evolution. CONCLUSIONS: In spite of ongoing, prolonged contact, conjugal leprosy is not frequent and requires several years to develop in the second person. Lepromatous leprosy in index cases was more frequently associated with leprosy in the couple. When the primary case was paucibacillary, no multibacillary leprosy occurred in the secondary case.

Adult↗
PubMed1978

Serologic response of vaccinated cattle to strains of Moraxella bovis isolated during epizootics of keratoconjunctivitis.

In studies to determine whether there were antigenic differences between strains (isolates) of Moraxella bovis, the sera from vaccinated calves were tested with isolates of M bovis while the calves were experiencing epizootics of infectious bovine keratoconjunctivitis (IBK). Before the epizootics of IBK, the calves were intramuscularly vaccinated with a formalin-killed autogenous M bovis bacterin. During the epizootics, the eyes were examined by cultural technique, and isolates which were obtained were categorized by catalase activity, source (diseased or nondiseased eyes), and reactivity with the various sera. The serum reactivity of the isolates was compared with that of the vaccinal strain. The vaccinal strain and 8 of the 1 5 selected isolates obtained during the 1974 epizootic were catalase negative. Seven of the 15 isolates from the 1974 epizootic and all of the selected isolates from the 1975 epizootic were catalase positive. A significantly higher (P less than 0.01) percentage of calf sera were serologically reactive with the vaccinal strain and other catalase-negative isolates (45.0%) than with catalase-positive isolates (34.8%). The results, although not definitive, suggest that there may be antigenic differences among strains of M bovis. These differences should be considered when cattle are vaccinated against IBK under natural conditions of exposure.

Animals↗
PubMed1976

Mycoplasmas and ovine keratoconjunctivitis.

The clinical course of an outbreak of keratoconjunctivitis in housed lambs and their dams was followed. Signs were transient generally and became severe in only a small proportion of lambs. The outbreak became most obvious when the lambs were 46 to 55 days old, when 46.9 per cent were affected. Mycoplasma conjunctivae isolations, confirmed by comparison with the type strain by biochemical and serological reactions, increased to 62.1 per cent of all eyes swabbed, but no correlation could be demonstrated between presence of the organism and clinical status. The reasons for this are discussed. Mycoplasma ovipneumoniae was also recovered from the eyes of a small number of lambs. Instillation of a broth culture of M conjunctivae into the conjunctival sacs of four hoggs produced a transient keratoconjunctivitis similar to that observed in the field, but no effect was observed in animals inoculated intravenously. M conjunctivae may therefore be the aetiological agent of non-follicular infectious ovine keratoconjunctivitis, although further work in gnotobiotic or specific pathogen free lambs is required to establish the fact beyond doubt.

Animals↗
PubMed1993

Q pili enhance the attachment of Moraxella bovis to bovine corneas in vitro.

Moraxella bovis, the causative agent of infectious bovine keratoconjunctivitis, exhibits several virulence factors, including pili, haemolysin, leukotoxin, and proteases. The pili are filamentous appendages which mediate bacterial adherence. Prior studies have shown that Q-piliated M. bovis Epp63 are more infectious and more pathogenic than I-piliated and non-piliated isogenic variants, suggesting that Q pili per se, or traits associated with Q-pilin expression, promote the early association of Q-piliated bacteria with bovine corneal tissue. In order to better evaluate the role of Q pili in M. bovis attachment, several M. bovis strains and a recombinant P. aeruginosa strain which elaborates M. bovis Q pili but not P. aeruginosa PAK pili, were evaluated using an in vitro corneal attachment assay. For each strain tested, piliated organisms attached better than non-piliated bacteria. M. bovis Epp63 Q-piliated bacteria adhered better than either the I-piliated or non-piliated isogenic variants. Finally, recombinant P. aeruginosa organisms elaborating M. bovis Q pili adhered better than the parent P. aeruginosa strain which did not produce M. bovis pili. These results indicate that the presence of pili, especially Q pili, enhances the attachment of bacteria to bovine cornea in vitro.

Animals↗
PubMed1986

[Pathogenetic significance of the psychrophilia of Yersinia pseudotuberculosis].

The work presents the data indicating that the temperature of Y. pseudotuberculosis cultivation is very important in regulating the activity of pathogenicity factors, necessary for the initiation of the pathogenic process in the cells of the macroorganism. Low temperature (8-10 degrees C), necessary for the growth of Y. pseudotuberculosis, facilitates the activation of invasive and toxic pathogenicity factors. At a growth temperature of 37 degrees C the inhibition of such necessary attributes of virulence as adhesion and invasion into epithelial cells occurs in Y. pseudotuberculosis, which decreases the capacity of these bacteria for inducing the infectious process. The virulence of Y. pseudotuberculosis population, lost as the result of its cultivation in synthetic culture media at a temperature of 37 degrees C, has been found to be restored at low temperature.

Animals↗
PubMed2000

[Polymerase chain reaction (PCR) for microbiological diagnosis in refractory infectious keratitis: a clinical study in 16 patients].

BACKGROUND: The identification of the causative pathogen in infectious keratitis is possible in only 60% of the cases. The aim of this study was to show if this number increases by the use of PCR. PATIENTS AND METHODS: In a series of 16 eyes with infectious keratitis corneal specimens were collected for culture and PCR. Serology (HSV, VZV, and Borrelia) was performed in all eyes, with exception of the 4 eyes presenting an acute form of keratitis, which obviously was bacterial origin. RESULTS: In all 4 cases of acute keratitis the causative pathogen (Pseudomonas aeruginosa) was detected by both culture and PCR. Of the remaining 12 eyes PCR was capable to identify the causative pathogen in 11 eyes. In 3 eyes herpes simplex virus was detected, in 3 eyes Moraxella catharalis, in 2 eyes Borrelia burgdorferii, in 2 eyes varizella zoster virus, and in 1 eye Bartonella henselae. Culture was positive in only 2 eyes, infected by Moraxella catharalis. CONCLUSIONS: PCR is a useful supplement in the microbiological diagnostic of infectious keratitis, in particular if only a small amount of pathogens are available (non-acute form) or if the eye has been treated by antibiotics prior to the microbiological diagnostic.

Chronic Disease↗
PubMed1988

Purification, characterization, and pathogenicity of Moraxella bovis pili.

Pilins composed of the alpha or beta pilins of Moraxella bovis strain Epp63 were purified, subjected to chemical or enzymatic cleavage, and the resulting fragments sequenced by automated Edman degradation. alpha Pilin was found to be a 155-amino-acid polypeptide with a single intramolecular disulfide bridge. The beta pilin amino acid sequence substantiated the previously reported structure derived from the beta pilin gene DNA sequence, and indicated that the alpha and beta pilins of this strain are approximately 70% homologous. DNA hybridization studies of genomic DNA from the alpha- and beta-piliated variants of strain Epp63 indicated that the expression of the two pilin types was governed by an oscillating mechanism of chromosomal rearrangement. The alpha and beta pili were evaluated serologically and found to exhibit approximately 50% shared antigenicity, indicating that regions of conserved and heterologous sequence specify both type-specific and crossreacting epitopes. The pathogenicity of the alpha- and beta-piliated variants was studied by ocular inoculation of calves eyes; beta-piliated organisms were significantly more infectious than alpha-piliated organisms, indicating that beta pili confer, or are associated with, a relative advantage during the first stages of ocular infection. Preliminary analysis of other M. bovis strains suggests that each strain produces two types of pilin, and that this property may be characteristic of the species.

Amino Acid Sequence↗
PubMed1991

Ocular pharmacology.

Application of sound ocular therapeutic principle is more difficult in food animals than most other species. Financial or husbandry constraints limit the practitioner's ability to use the entire range of ocular drugs available or to use them with adequate frequency. These problems may be dealt with by using systemically administered drugs when effective or by employing vehicles or delivery techniques that necessitate minimal dosing frequency. By far the most important medically treatable eye disease encountered in food animal practice is IBK. Effective therapies include systemic administration of long-acting oxytetracycline, subconjunctival administration of a variety of antibiotics, or topical application of benzathine cloxacillin. Infectious conjunctivitis in sheep and goats due to a variety of agents may be treated successfully with tetracycline in most cases. Conjunctivitis and keratitis secondary to IBR virus usually are given supportive therapy only, although specific antiviral drugs have been used in the treatment of herpetic eye disease in other species. Anterior uveitis is best treated by corticosteroid and mydriatic therapy in addition to treatment of the underlying cause, if identified.

Animals↗
PubMed1988

New approach for early, simple, and rapid detection of acute eye infections.

Several methods are known for the diagnosis of infections all of which require the use of well equipped laboratories and skilled personnel. For example: 1. Isolation and culturing of microorganisms from samples taken from body fluids. This method is complicated and time consuming. 2. Detection of antibodies. The main disadvantage of this method is the fact that the change in the level of antibodies occurs only after a few days from the onset of the disease. In the course of our work we found that already in the early stages of acute external eye infections, mucopolysaccharide degrading enzymes (MPDE) appear in tear fluid, where they are normally not present. We also found a relationship between MPDE with different infectious diseases of the eye as well as their role in the progress and treatment of these diseases. As a result of these findings and numerous clinical and laboratory in vivo animal and in vitro experiments, we developed a new approach for early detection of acute ocular infections. Utilizing this approach based on tear samples from patients; eyes, we developed a method which enables quick and reliable detection of the presence of an infection in general, and for early diagnosis in particular. Testing MPDE in tears with this method revealed also a new phenomenon of specific geometric imprints, or orthographic signs, each of which may be indicative of a different type of acute infection, e.g. adenovirus, herpes simplex virus-1, or other acute viral and bacterial infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Microsporidial keratoconjunctivitis in acquired immunodeficiency syndrome.

We describe three patients with acquired immunodeficiency syndrome who presented with a bilateral coarse superficial epithelial keratitis due to infection with the protozoal parasite Microspora, Encephalitozoon cuniculi. Despite the extent of the corneal surface disease, conjunctival inflammation was minimal. Visual acuity ranged from 20/20 to 20/200. In one patient, the keratitis was complicated by the development of a surface defect with secondary Pseudomonas species infection. All patients had a history of exposure to household pets. Standard cultures were negative. Diagnosis was established in two of the three cases based on characteristic appearance of the protozoan in conjunctival scrapings. Electron microscopy of a conjunctival biopsy specimen in one patient confirmed the species. No recognized effective treatment is available for this infection.

Acquired Immunodeficiency Syndrome↗
PubMed2005

[Epidemic keratoconjunctivitis. Detecting adenoviruses].

OBJECTIVE: The validity of the 15-min adenovirus assay SAS Adenotest was evaluated compared with virus detection by polymerase chain reaction (PCR) from conjunctival swabs. METHODS: In 75 patients with assumed epidemic keratoconjunctivitis, adenovirus detection from conjunctival swabs was performed by the immunochromatographic assay SAS Adenotest and PCR. RESULTS: In 25 patients adenovirus was detected by PCR, 18 of whom were detected by the SAS Adenotest and 7 of whom were not. No false positive results occurred. Sensitivity was 72% and specificity was 100%. CONCLUSIONS: The results indicate that rapid adenovirus detection with the SAS Adenotest is a useful tool in early epidemic keratoconjunctivitis. An additional PCR should be performed when clinical symptoms persist for 5 days or more.

Adenoviridae↗
PubMed1997

[Staphylococcus-associated blepharokeratoconjunctivitis. Clinical findings, pathogenesis and therapy].

BACKGROUND: Staphylococci represent an important source of external infections of the eye. In addition to acute staphylococcal conjunctivitis a spectrum of subacute or chronic disease may be found. According to Valenton und Okumoto, with this staphylococci-associated blepharo-kerato-conjunctivitis in culture-positive cases S. aureus is found in 31% and S. epidermidis in 69% of smears. Microbiallergic and toxic mechanisms are the underlying etiology. PATIENTS: We report on a series of 38 patients with "red eye" that were seen between 1992 and 1994 in the external disease clinic at the Department of Ophthalmology, University of Heidelberg. RESULTS: There were 17 female and 21 male patients. The mean age was 53 +/- 20 years. The patient's complaints included recurrent red eyes with discomfort and pain. Clinically, a squamous blepharitis (63%) and conjunctivitis (87%) were present. Upon biomicroscopic evaluation, a corneal involvement could be found in 80% of cases. In 66% of cases conjunctival swabs were positive for staphylococci. DISCUSSION: The blepharitis may be squamous or ulcerative. The underlying cause is a dermal irritation by staphylococcal toxins. As early as 1937, Thygeson and Allan postulated a toxin-induced skin irritation by a "dermonecrotic factor." In chronic cases a papillary conjunctivitis caused by a toxin reaction can be observed. Histologically, no lymph follicles or eosinophils are present. Several types of keratitis and corneal involvement are found. An epithelial keratitis is caused by toxic mechanisms. Marginal infiltrates and ulcers indicate an antigen-antibody reaction. Phlyctenulae indicate a delayed immune reaction (Gell and Coombs type IV). Complications include vascular pannus, corneal scarring, and rarely corneal melting and ulcers. Therapy depends on the severity of the inflammation and the underlying pathomechanism. This includes reduction of toxin-producing organisms by hygiene of the lid margins and application of topical disinfectants and antibiotics. With immunological phenomena topical steroids are required.

Adolescent↗