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PubMedDate not supplied

Subacute bacterial endocarditis due to Actinobacillus actinomycetemcomitans.

Sixteen documented cases of Actinobacillus actinomycetemcomitans endocarditis have been reported in the past 15 years. The characteristic granular growth and the fastidious nature and slow-growing character of this organism decrease the yield of positive blood cultures. Two recently observed cases of subacute endocarditis due to Actinobacillus are reported, one in a patient who required surgical intervention for complications of his disease and the other case associated with an aortic prosthetic valve. The first patient had late embolic complications which are commonly seen with Actinobacillus endocarditis. A review of the literature; including a synoptic table with clinical failures, treatment, and outcome is presented. Unless special care is taken to isolate these slow growing organisms, these cases will be misclassified as culture negative endocarditis.

Actinobacillus↗
PubMed1996

Molecular characterization of a common 48-kilodalton outer membrane protein of Actinobacillus pleuropneumoniae.

Previous studies have shown that a vaccine prepared from outer membranes of Actinobacillus pleuropneumoniae serotype 5 can elicit protective immunity in swine against challenge with either serotype 5 or serotype 1. These results suggest the presence of common subcapsular surface antigens, such as outer membrane proteins, that contribute to cross-protective immunity. We have identified a 48-kDa outer membrane protein that is common to all 12 capsular serotypes of A. pleuropneumoniae but is not present in the outer membranes of related species of gram-negative swine pathogens. This protein is immunogenic in swine infected with either A. pleuropneumoniae serotype 5 or 1A, as well as in swine vaccinated with A. pleuropneumoniae serotype 5 outer membranes. This 48-kDa protein is readily detected in outer membranes produced by sucrose density gradient centrifugation, but it is sarcosyl soluble and therefore not found in outer membranes prepared by detergent treatment. The gene encoding the 48-kDa outer membrane protein has been cloned from A. pleuropneumoniae serotype 5 and and has been designated aopA, for Actinobacillus outer membrane protein A. The gene is 1,347 bp in length and encodes a protein, designated AopA, of 449 amino acids with a predicted molecular weight of 48,603. Southern blot analysis under high-stringency conditions showed that strains of all 12 serotypes of A. pleuropneumoniae contain DNA homologous to this gene, as do strains of two closely related species, Actinobacillus suis and Pasteurella multocida. Whether antibodies against the AopA antigen contribute to cross-protective immunity against A. pleuropneumoniae infection remains to be determined.

Actinobacillus Infections↗
PubMed2001

Clinical significance and taxonomy of Actinobacillus hominis.

Clinical findings in 36 immunosuppressed patients with lower respiratory tract infection or bacteremia with Actinobacillus hominis are described. Animal contact was only recorded for three patients; nine patients died despite appropriate antimicrobial treatment. Although infections with this microorganism seem to be rare, the fact that 37 of 46 strains characterized in this study have been found in Copenhagen indicates that under-reporting may occur. A. hominis is phenotypically relatively homogeneous but can be difficult to differentiate from other Actinobacillus species unless extensive biochemical testing is performed. Mannose-positive strains of A. hominis are especially difficult to differentiate from A. equuli. Attempts to identify A. hominis by automatic identification systems may lead to misidentifications. Ribotyping and DNA-DNA hybridization data show that A. hominis is a homogeneous species clearly separated from other species within the genus Actinobacillus.

Actinobacillus↗
PubMed2002

Circulating cortisol, tumor necrosis factor-alpha interleukin-1beta, and interferon-gamma in pigs infected with Actinobacillus pleuropneumoniae.

This study evaluated the time course of systemic cytokine concentrations in an acute model of pneumonia in pigs challenged intranasally with Actinobacillus pleuropneumoniae. Feed intake and serum cortisol were measured as overt clinical and systemic markers of disease onset, respectively, and serum tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma as representative systemic inflammatory markers. Crossbred barrows (n = 15), approximately 5 wk of age, were used in the study. Pigs were housed in an environmentally controlled facility at 25 degrees C and under continuous illumination in pens measuring approximately 1.5 m2. Pigs had free access to water and an unmedicated diet. Approximately 1 wk prior to disease challenge, pigs were fitted nonsurgically with venous catheters. At challenge, pigs were given 5 x 10(8) CFU Actinobacillus pleuropneumoniae intranasally (n = 8) or a similar volume of sterile growth media intranasally (Control; n = 7). Feed intake was estimated by the change in feeder weight at 12-h intervals from -12 to 72 h relative to the time of disease challenge. Blood sampling began 12 h prior to challenge and continued until 72 h after challenge. Pigs were sampled at -12, -6, and 0 h, then at 90-min intervals until 12-h post-challenge, continuing at 3-h intervals until 24-h post-challenge, then again at 6-h intervals until 72 h after challenge. Serum was harvested and frozen until assayed for cortisol, tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma. Feed intake was reduced in Actinobacillus pleuropneumoniae pigs during the intervals 0 to 12 h (P < 0.001), 24 to 36 h (P < 0.001), 48 to 60 h (P <0.05), and 60 to 72 h (P < 0.05). TheActnobacillus pleuropneumoniae-challenged pigs had elevated serum cortisol from 180-min to 18-h post-challenge (P < 0.001) and also at 36 (P < 0.05), 42 (P < 0.001), and 60 (P < 0.05) h following infection. Circulating cytokines were not affected by disease challenge. Thus, in this experimental model of pneumonia, weaned pigs demonstrated expected behavioral and endocrine characteristics of disease in the absence of significant changes in circulating inflammatory cytokines.

Actinobacillus Infections↗
PubMed1986

Endogenous endophthalmitis caused by Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans is a rare cause of infection in humans. It has been mainly reported in cases of endocarditis and destructive periodontal disease. This report describes the case of a 51-year-old female who had an acute onset of anterior iridocyclitis, followed by the appearance of a white nodule on the lens and subsequent involvement of the vitreous. The course of the disease was long and insidious. Actinobacillus actinomycetemcomitans was isolated from 3 of 26 blood cultures drawn over a period of 40 days, and also from the vitreous. The patient had been suffering from periodontal disease for 3 months prior to her admission. Only two cases of endophthalmitis presumably caused by this organism have previously been reported, but the organism has never been recovered from the eye. This report presents the first case of culture-proven Actinobacillus actinomycetemcomitans endophthalmitis following destructive periodontal disease.

Actinobacillus↗
PubMed1993

Detection of Actinobacillus pleuropneumoniae in the porcine upper respiratory tract as a complement to serological tests.

Attempts were made to isolate Actinobacillus pleuropneumoniae from the nasal cavities and tonsils of 442 healthy pigs from 15 herds. Samples were streaked onto different media formulations. Serum samples were assayed for antibodies to A. pleuropneumoniae by enzyme-linked immunosorbent assay and complement fixation test. Actinobacillus pleuropneumoniae was isolated from the nasal cavities only in 24 pigs, from tonsils only in 90 pigs, and from both the nasal cavities and the tonsils in 11 pigs. A PPLO medium supplemented with lincomycin, bacitracin and crystal violet allowed recovery of A. pleuropneumoniae from more animals than a tryptic soy agar medium from both sites. Incubation of plates in an enriched CO2 atmosphere did not affect the recovery rate. Actinobacillus pleuropneumoniae belonging to serotypes 1, 2, 3, 5a, 5b, 7, 8, 10 and 12 were isolated, and, in several herds, more than one serotype were recovered. Serotypes of A. pleuropneumoniae were isolated from nine herds which were found seronegative to these. The isolation of A. pleuropneumoniae from the upper respiratory tract can be useful for detection of carrier pigs and complements serological screening.

Actinobacillus Infections↗
PubMed1991

Immunological properties of Actinobacillus pleuropneumoniae hemolysin I.

The 105 kDa hemolysin I protein from Actinobacillus pleuropneumoniae serotype I type strain 4074 (HlyI) was shown by immunoblot analysis to be the predominant immunogenic protein if convalescent field sera or sera from pigs experimentally infected with A. pleuropneumoniae serotype 1 were used. SDS gel- and immunoblot-analysis using total culture, washed cells or culture supernatant showed that HlyI is essentially secreted and is not found attached to the bacteria. Proteins in the 105 kDa range that react strongly with anti-HlyI antibody, are produced by all serotypes and are presumed to be their hemolysins. Sera from pigs experimentally infected with each of the 12 serotypes strongly reacted with HlyI. In addition, some sera from pigs that were confirmed to be negative for A. pleuropneumoniae, also reacted with HlyI as well as with related proteins from Actinobacillus rossii and Actinobacillus suis. These two species produce proteins in the 105 kDa range which cross-react strongly with HlyI. They could be the source of the immunological reactions of the A. pleuropneumoniae-negative sera with HlyI. However, no cross-reactions could be found between HlyI and the Pasteurella haemolytica leukotoxin, the Escherichia coli alpha-hemolysin or related proteins from various hemolytic E. coli strains isolated from pigs. The immunological cross-reactions of HlyI with related proteins from A. rossii, A. suis and possibly from other bacterial species may create uncertainty in interpretation if HlyI is used as the antigen in serodiagnosis of A. pleuropneumoniae.

Actinobacillus↗
PubMedDate not supplied

Biological characterization of Actinobacillus species and Pasteurella ureae.

Forty-seven strains of Actinobacillus and eleven strains of Pasteurella urea were studied using 119 morphological, physiological and biochemical characters. The resulting data were subjected to numerical analysis using the complement of Gower's coefficient excluding negative matches. Clustering was by unweighted pair group average linkage. At distance level 0.30, seven phenons and five isolated strains (including one strain of "A. seminis ") were obtained. The seven phenons correspond to Actinobacillus lignieresii , A. suis, A. equuli , A. capsulatus, "A. salpingitidis ", Actinobacillus sp. (Ross) and P. ureae. The characteristics allowing identification of the seven phenons are tabulated.

Actinobacillus↗
PubMed1998

Actinobacillus scotiae sp. nov., a new member of the family Pasteurellaceae Pohl (1979) 1981 isolated from porpoises (Phocoena phocoena).

Phenotypic and phylogenetic studies were performed on a Gram-negative, rod-shaped bacterium isolated from three porpoises. Biochemical and physiological studies indicated that the bacterium was related to the family Pasteurellaceae. Comparative 16S rRNA gene sequencing studies confirmed these findings and demonstrated that the bacterium represents a hitherto unknown subline. The nearest phylogenetic relative of the unknown bacterium was Actinobacillus delphinicola, an organism also originating from sea mammals, although a sequence divergence of 3% demonstrated that the newly isolated bacterium is a distinct species. On the basis of the results of the phylogenetic analysis and phenotypic criteria, it is proposed that the bacterium should be classified as a new species, Actinobacillus scotiae sp. nov. The type strain of Actinobacillus scotiae sp. nov. is NCTC 12922T (= M2000/95/1T).

Actinobacillus↗
PubMed1993

Electron microscopy of phages in serotypes of Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans, Actinobacillus ureae, Haemophilus aphrophilus, Haemophilus paraphrophilus, Haemophilus influenzae, Haemophilus parainfluenzae, Pasteurella haemolytica and Pasteurella multocida strains were examined by transmission electron microscopy for the presence of bacteriophages. Phages were detected in serotype a (SUNY 75) and e (UOH 1705) and in the fresh clinical isolates UOH Q1243 and UOH Q1247 of A. actinomycetemcomitans. Phages were not found in serotype b, c and d strains of A. actinomycetemcomitans, in the fresh clinical isolate UOH Q1244 of this species or in old strains (including reference strains) of related species from the Actinobacillus-Haemophilus-Pasteurella group.

Actinobacillus↗
PubMed1986

Actinobacillus muris sp. nov. isolated from mice.

Several unclassified strains were obtained during investigations of the aerobic pharyngeal flora of healthy white laboratory mice originating from four different colonies. Nineteen strains formed a group tentatively designated taxon 12. Comparative investigations including taxon 12, P. ureae sensu stricto. "P. urea" strain Ackerman 80-443D, P. pneumotropica sensu stricto, P. pneumotropica type Heyl, P. pneumotropica type Henriksen and "H. influenzae-murium" showed that taxon 12 was identical with "P. ureae" strain Ackerman 80-443D but different from P. ureae sensu stricto and other species belonging to the family Pasteurellaceae Pohl 1981. The G + C content of DNA from the suggested reference strain for taxon 12 was within the limits for Pasteurellaceae. DNA:DNA hybridizations linked taxon 12 to the genus Actinobacillus via the avian hemolytic Actinobacillus-like complex (27). The name Actinobacillus muris is proposed for taxon 12.

Actinobacillus↗
PubMed1988

Monoclonal antibodies to Actinobacillus actinomycetemcomitans.

Murine hybridoma cell lines were developed which synthesized monoclonal antibodies against Actinobacillus actinomycetemcomitans-associated antigens. Monoclonal antibodies specific for an antigen(s) common to all A. actinomycetemcomitans isolates tested but not detected on other gram-negative oral plaque microorganisms or other Actinobacillus species were identified. Monoclonal antibodies specific for each serotype group of A. actinomycetemcomitans which did not bind to other Actinobacillus species or oral plaque microorganisms were also identified.

Actinobacillus↗
PubMed1990

Nucleotide sequence of the leukotoxin gene from Actinobacillus actinomycetemcomitans: homology to the alpha-hemolysin/leukotoxin gene family.

The leukotoxin produced by Actinobacillus actinomycetemcomitans has been implicated in the etiology of localized juvenile periodontitis. To initiate a genetic analysis into the role of this protein in disease, we have cloned its gene, lktA. We now present the complete nucleotide sequence of the lktA gene from A. actinomycetemcomitans. When the deduced amino acid sequence of the leukotoxin protein was compared with those of other proteins, it was found to be homologous to the leukotoxin from Pasteurella haemolytica and to the alpha-hemolysins from Escherichia coli and Actinobacillus pleuropneumoniae. Each alignment showed at least 42% identity. As in the other organisms, the lktA gene of A. actinomycetemcomitans was linked to another gene, lktC, which is thought to be involved in the activation of the leukotoxin. The predicted LktC protein was related to the leukotoxin/hemolysin C proteins from the other bacteria, since they shared a minimum of 49% amino acid identity. Surprisingly, although actinobacillus species are more closely related to pasteurellae than to members of the family Enterobacteriaciae, LktA and LktC from A. actinomycetemcomitans shared significantly greater sequence identity with the E. coli alpha-hemolysin proteins than with the P. haemolytica leukotoxin proteins. Despite the overall homology to the other leukotoxin/hemolysin proteins, the LktA protein from A. actinomycetemcomitans has several unique properties. Most strikingly, it is a very basic protein with a calculated pI of 9.7; the other toxins have estimated pIs around 6.2. The unusual features of the A. actinomycetemcomitans protein are discussed in light of the different species and target-cell specificities of the hemolysins and the leukotoxins.

Actinobacillus↗
PubMed2001

Specific immune response of mares and their newborn foals to Actinobacillus spp. present in the oral cavity.

Oral swab samples, serum and colostrum was taken from 15 mares and 14 of their foals, within 24 h of birth. The presence of antibody against Actinobacillus spp. isolated from the oral cavity was investigated using agar gel immunodiffusion. Antibodies against 48 out of the 77 Actinobacillus isolates from all horses in the study were present in the respective sera of 13 mares and 9 foals. In 11 mother-foal pairs, the antibody content of the foal serum was similar to that of the mare, and in 9 cases this was reflected in the antibody content of colostrum from the mare. The results indicate that an immune response to Actinobacillus spp. colonising the oral cavity is present in many adult horses and that this immune response can be transferred from mother to foal via colostrum.

Actinobacillus↗
PubMed1986

Isolation of members of the Haemophilus-Pasteurella-Actinobacillus group from feral rodents.

46 feral rodents, including a common vole (Microtus arvalis), house mice (Mus musculus), muskrats (ondatra zibetica), house rats (Rattus rattus) and brown rats (R. norvegicus) were examined for bacteria of the Haemophilus-Pasteurella-Actinobacillus group. Haemophilus spp. (only M. musculus examined) were not obtained. All animal species were found contaminated by P. pneumotropica and/or Actinobacillus spp. Almost all M. musculus (96%) and most Rattus spp. (76%) were contaminated by P. pneumotropica and/or Actinobacillus spp. These bacteria were obtained most frequently from the upper respiratory tract, to a lesser extent from the lung and rarely from caecal contents. It is concluded that feral rodents might constitute an important source of contamination of laboratory rodents by members of the HPA-group.

Actinobacillus↗
PubMed2000

Distribution of diaminopropane, putrescine and cadaverine in Haemophilus and Actinobacillus.

Cellular levels of diaminopropane, putrescine and cadaverine, and decarboxylase activities to produce these diamines in six species (16 strains) of Haemophilus and four species (5 strains) of Actinobacillus belonging to the family Pasteurellaceae of the gamma subclass of the class Proteobacteria, were determined by high performance liquid chromatography (HPLC). Diaminopropane was ubiquitously distributed within all Haemophilus and Actinobacillus species, and L-2,4-diaminobutyric acid decarboxylase activity was detected in them. Putrescine and ornithine decarboxylase activity were found in H. aphrophilus, H. parainfluenzae and H. influenzae (type a, b, d, e and f except for type c) but not detected in H. aegyptius, H. parahaemolyticus, H. ducreyi and Actinobacillus species. Cadaverine occurred in H. aphrophilus, H. aegyptius, H. influenzae, H. parainfluenzae, A. actinomycetemcomitans, A. equuli and A. lignieresii, whereas their lysine decarboxylase activity was scarcely detected. Cadaverine was not found in H. parahaemolyticus, H. ducreyi and A. suis. The diamine profile serves as a phenotypic marker for the chemotaxonomic classification of the family Pasteurellaceae.

Actinobacillus↗
PubMed1990

Interactions of Haemophilus-Actinobacillus-Pasteurella bacteria with phagocytic cells.

The Haemophilus-Actinobacillus-Pasteurella (HAP) group of bacteria contains a number of important veterinary and human pathogens. Although each species has specific characteristics and host range, most share the general property of being resistant to cellular defense mechanisms. In some cases (e.g. Pasteurella multocida, Pasteurella haemolytica and Actinobacillus pleuropneumoniae) resistance results in part from the presence of an antiphagocytic capsule that protects the bacilli against ingestion by neutrophils and macrophages. In other instances the bacteria aggressively attack mononuclear and polymorphonuclear phagocytes. For example, P. haemolytica, A. pleuro-pneumoniae and Actinobacillus actinomycetemcomitans each produce a leukotoxin that functionally impairs, and ultimately kills, leukocytes from cattle, pigs and human beings, respectively. Components of Pasteurella multocida and Haemophilus somnus have also been reported to adversely affect leukocyte functions. Another important area of research that is just emerging concerns the ability of lipopolysaccharide and other components of HAP bacteria to stimulate or modulate macrophage release of inflammatory mediators such as interleukin-1. In this paper, we provide an overview of the interactions of HAP bacteria with phagocytes and identify some of the common strategies by which they evade cellular defenses.

Actinobacillus↗
PubMed1989

[Actinobacillus ureae meningitis. Apropos of a case].

A case of Actinobacillus ureae meningitis in a 52 year old man with an history of chronic sinusitis and previous skull fractures is reported. Actinobacillus ureae, called for a long time Pasteurella ureae, is a rare cause of meningitis as shown by a short review of the literature (eight cases reported). We have searched the bacteria in the rhinopharynx of the patient's four dogs: this search was unsuccessful in agreement with the literature data which has not yet established an animal host for Actinobacillus ureae.

Actinobacillus Infections↗