Comparative studies on Actinomyces pyogenes and Arcanobacterium haemolyticum

Antimicrobial Resistance in Corynebacterium spp., Arcanobacterium spp., and Trueperella pyogenes

There is currently only limited information on the antimicrobial susceptibility and resistance of Corynebacterium spp., Arcanobacterium spp., and Trueperella pyogenes from animals. The comparability of the data is hampered by the use of different antimicrobial susceptibility testing methods and interpretive criteria. To date, standard broth microdilution methods and clinical breakpoints that are approved by the Clinical and Laboratory Standards Institute and are applicable to Corynebacterium spp., Arcanobacterium spp., and T. pyogenes are available. The lack of species-specific clinical breakpoints for the different animal species reduces the explanatory power of the data. Among the isolates of the three genera, elevated MICs for different classes of antimicrobial agents (e.g., β-lactams, macrolides, lincosamides, tetracyclines, aminoglycosides, phenicols, sulfonamides/diaminopyrimidines, and fluoroquinolones) have been described. The most comprehensive data set is available for T. pyogenes, which also includes information about genes and mutations involved in antimicrobial resistance. In T. pyogenes isolates, the macrolide-lincosamide-streptogramin B resistance genes erm(B) and erm(X) were identified. Tetracycline resistance in T. pyogenes was based on the resistance genes tet(W), tet(Z), and tet(33), whereas the aminoglycoside resistance genes aacC, aadA1, aadA2, aadA5, aadA24, and aadB have been described in T. pyogenes. So far, only single genes conferring either phenicol resistance (cmlA6), trimethoprim resistance (dfrB2a), or β-lactam resistance (blaP1) are known to occur in T. pyogenes isolates. Various 23S rRNA mutations, including A2058T, A2058G, and G2137C, were identified in macrolide/lincosamide-resistant T. pyogenes.

Synergistic and antagonistic hemolytic activities of bacteria of genus Arcanobacterium and CAMP-like hemolysis of Arcanobacterium phocae and Arcanobacterium haemolyticum with Psychrobacter phenylpyruvicus

A total of 57 bacteria representing eight species of genus Arcanobacterium (A.) were investigated for hemolytic properties on blood agar containing sheep and rabbit blood and for CAMP-like reactions. An enhanced hemolysis on blood agar containing rabbit blood compared to sheep blood could be observed for A. haemolyticum, less pronounced for A. hippocoleae and A. pluranimalium. A synergistic hemolytic reaction with staphylococcal beta-hemolysin appeared to be constantly visible for A. hippocoleae, A. pluranimalium and A. pyogenes, with Streptococcus agalactiae for A. phocae and A. haemolyticum, with Rhodococcus equi for A. phocae, A. haemolyticum, A. pluranimalium and A. pyogenes and with A. haemolyticum for A. hippocoleae, A. pluranimalium and A. pyogenes, respectively. A reverse CAMP-reaction in the zone of staphylococcal beta-hemolysin could be observed for A.phocae and A.haemolyticum. In addition, a novel CAMP-like reaction could be noted between Psychrobacter phenylpyruvicus, identified by 16S rDNA sequencing, and A. phocae and A. haemolyticum. These synergistic or antagonistic hemolytic properties could possibly be used as additional criteria for identification of bacteria of genus Arcanobacterium.

Phenotypic and genotypic characterization of Arcanobacterium haemolyticum isolates from infections of horses

The present study was designed to characterize phenotypically and genotypically seven Arcanobacterium haemolyticum strains obtained from infections of six horses. All seven strains showed the cultural and biochemical properties typical of A. haemolyticum and were susceptible to most of the antibiotics tested. The species identification could be confirmed by amplification and sequencing of the 16S rRNA gene and the 16S-23S rRNA intergenic spacer region and by PCR amplification of species-specific parts of the gene encoding phospholipase D in A. haemolyticum. Use of the latter could possibly improve future identification of this generally human pathogenic bacterial species which, according to the present results, seems to occur also in infections of horses.

Further characterization of alpha 2-macroglobulin binding properties of Actinomyces pyogenes

Binding of 125I-labelled alpha 2-macroglobulin (alpha 2M) to Actinomyces pyogenes was investigated. The binding of alpha 2M proved to be time dependent, saturable, and could be inhibited by unlabelled alpha 2M, but not by fibrinogen, haptoglobin, fibronectin, or albumin. The alpha 2M binding site was sensitive to treatment with proteolytic enzymes and heat, indicating its protein nature. The dissociation constant (Kd) was 4.447 x 10(-9) M, and the number of binding sites per bacterial cell was calculated to be 5200. The kinetic analysis indicated an homogeneous population of binding sites. Binding of alpha 2M to the surface of A. pyogenes had no significant influence on the phagocytosis of the bacteria by polymorphonuclear leucocytes.

Clinical microbiology of coryneform bacteria

Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed.

Purification and further characterization of a haemolysin of Actinomyces pyogenes

A haemolysin produced by Actinomyces pyogenes ATCC 8164 was purified from culture supernatant by ammonium sulphate and polyethylene glycol precipitation, ion-exchange chromatography on DEAE-Sephacel, and fast-protein-liquid-chromatography on Superose 12 prep grade. The purified haemolysin, designated as pyolysin, displayed a single band on poly-acrylamide gel electrophoresis, indicating a molecular weight of 55000. Additionally, using gel filtration, the same molecular weight was estimated. Further studies of the eluate of ion-exchange chromatography using isoelectric focusing also revealed a single protein band at pH 9.38 with haemolytic activity. A specific antiserum produced against pyolysin inhibited the haemolytic activity. The purity of the isolated protein was also determined by Western Blot analysis with antiserum obtained from a cow inoculated with culture supernatant from A. pyogenes and Peptococcus indolicus. The isolated pyolysin appeared to be heat-labile and displayed cytotoxic effects on poly-morphonuclear leucocytes and on pTK2 kidney cells.

Characterization of fibrinogen-binding properties of Actinomyces pyogenes

This study was designed to further characterize the fibrinogen-binding properties of Actinomyces pyogenes. The fibrinogen-binding capacities of a selected A. pyogenes culture could be significantly enhanced by heat pretreatment (60 degrees C, 1 h) of the bacteria. The fibrinogen-binding site seemed to be a protein which was specific for fibrinogen. In phagocytosis studies, binding of fibrinogen to A. pyogenes significantly increased the phagocytic capacity of bovine polymorphonuclear leucocytes.

Antimicrobial susceptibility of Arcanobacterium haemolyticum

The susceptibilities of 138 clinical isolates of Arcanobacterium haemolyticum to 11 antimicrobial agents were tested. All strains were susceptible to phenoxymethylpenicillin, cephalosporins, erythromycin, azithromycin, clindamycin, vancomycin, doxycycline, and ciprofloxacin but were resistant to trimethoprim-sulfamethoxazole.

Adherence of Actinomyces pyogenes to HeLa cells mediated by hydrophobic surface proteins

Determination of cell-surface hydrophobicity of Actinomyces pyogenes by hydrophobic interaction chromatography on phenyl-Sepharose revealed that all 42 cultures examined were strongly hydrophobic. The hydrophobic surface proteins were solubilized by mutanolysin treatment of the bacteria and isolated by hydrophobic interaction chromatography. In SDS-PAGE, they appeared with numerous protein bands and blocked the adhesion of whole bacterial cells to the gel matrix. The A. pyogenes cultures attached to HeLa cells in varying degrees. This attachment of A. pyogenes was greatly reduced in the presence of isolated hydrophobic proteins and in the presence of specific antibodies produced against hydrophobic surface proteins. The results of the present study demonstrate that hydrophobic surface proteins promote the capacity of A. pyogenes to adhere to HeLa cells.

Isolation of gram-positive rods that resemble but are clearly distinct from Actinomyces pyogenes from mixed wound infections

Beginning in 1990, gram-positive rods resembling Actinomyces pyogenes were found with increasing frequency in mixed cultures from various infectious processes, most of them from patients with otitis, empyema, pilonidal cysts, perianal abscesses, and decubitus ulcers. Ribotyping and hybridization showed that these gram-positive rods could be divided into five groups not related to known Actinomyces species. Biochemical markers for reliable differentiation into these groups, however, could not be found. Therefore, naming new species is not warranted unless parameters are discovered that allow identification without DNA hybridization. These gram-positive rods have been isolated only in mixed cultures with anaerobes, Staphylococcus aureus, Streptococcus "milleri," enterococci, and gram-negative rods. Their exact role in these possibly synergistic infections needs further investigation.

Acute peritonsillar abscess caused by Arcanobacterium haemolyticum

A patient is reported with a peritonsillar abscess yielding Arcanobacterium haemolyticum. This appears to be only the fifth such case described in the medical literature and the first from Europe. The organism has been reported as an occasional cause of tonsillopharyngitis with rash, resembling infection with Streptococcus pyogenes but often unresponsive to penicillin therapy. A. haemolyticum easily passes unrecognized in bacteriological cultures as a result of its slow growth, coryneform appearance in the Gram's stain and weak haemolytic activity on conventional laboratory media.

A CAMP-like phenomenon in Serpulina (Treponema) spp

A CAMP-like phenomenon was observed in 40 Serpulina (Treponema) isolates from the intestines of pigs, dogs, mice and rats. The strains examined included reference strains of the serotypes 1-4 of Serpulina (Treponema) hyodysenteriae and Serpulina (Treponema) innocens. The possible pathogenic importance of this phenomenon is discussed.

Evaluation of the API Coryne test system for identification of Actinomyces pyogenes

The present study was designed to evaluate the accuracy of the API Coryne test system for identification of Actinomyces pyogenes. The test system correctly identified 36 of 42 A. pyogenes and 4 of 5 comparatively studied Arcanobacterium haemolyticum-cultures. The biochemical profiles of the remaining 6 A. pyogenes- and 1 A. haemolyticum-cultures were not included in the analytical profile index. None of the cultures were misidentified. According to the API database (ATB Plus V 1.5.4.) the unidentified cultures could be correctly identified as A. pyogenes and A. haemolyticum respectively. A greater repertoire of A. pyogenes specific biochemical profiles incorporated into the analytical profile index would improve the applicability of this test system for veterinary diagnostics.

Human infections with Actinomyces pyogenes (Corynebacterium pyogenes)

Actinomyces pyogenes (Corynebacterium pyogenes), a well-known pathogen in many animals, was isolated from 11 Danish patients since 1968. Bacteriologic characteristics and clinical pictures of the patients are described. Ability to hydrolyze gelatine, to produce beta-glucuronidase, to reach with antisera against group-G streptococci, and to produce acid from xylose differentiates A. pyogenes from Arcanobacterium haemolyticum, with which it has at times been confused. Actinomyces pyogenes is an established, but often misrecognized, human pathogen that should be better known to clinical microbiologists.

Cell surface hydrophobicity of Actinomyces pyogenes determined by hexadecane adherence- and salt aggregation studies

Cell surface hydrophobicities of Actinomyces pyogenes were determined by measuring the adherence of the bacteria to hexadecane droplets and by salt aggregation tests. Among 42 A. pyogenes cultures tested 25 (60%) adhered strongly (adherence greater than or equal to 75%) and 17 (40%) less pronounced (adherence between 25-75%) to the hexadecane droplets. Pre-treatment of the bacteria with proteolytic enzymes completely eliminated the adherence properties whereas heat treatment had no effect. The salt aggregation studies revealed that 4 (10%) cultures aggregated in ammonium sulfate solutions of a molarity of 0.05 mol/l, 5 (12%), 14 (33%) and 3 (7%) cultures in ammonium sulfate solutions with molarities of greater than or equal to 1.5 mol/l, greater than or equal to 3 mol/l and greater than or equal to 4.5 mol/l, respectively. No aggregation at all could be observed with 16 (38%) of the cultures. Pronase treatment completely eliminated the salt aggregation reactions, trypsin- and heat treatment had no effect. The results from hexadecane adherence and salt aggregation did not correspond. The differences in surface hydrophobicities, possibly related to adherence properties of A. pyogenes, could be used for epidemiological typing of individual cultures of this bacterial species.

Coryneform bacteria in infectious diseases: clinical and laboratory aspects

Coryneform isolates from clinical specimens frequently cannot be identified by either reference laboratories or research laboratories. Many of these organisms are skin flora that belong to a large number of taxonomic groups, only 40% of which are in the genus Corynebacterium. This review provides an update on clinical presentations, microbiological features, and pathogenic mechanisms of infections with nondiphtheria Corynebacterium species and other pleomorphic gram-positive rods. The early literature is also reviewed for a few coryneforms, especially those whose roles as pathogens are controversial. Recognition of newly emerging opportunistic coryneforms is dependent on sound identification schemes which cannot be developed until cell wall analyses and nucleic acid studies have defined the taxonomic groups and all of the reference strains within each taxon have been shown by molecular methods to be authentic members. Only then can reliable batteries of biochemical tests be selected for distinguishing each taxon.

Typing of Actinomyces pyogenes by its production and susceptibility to bacteriocin-like inhibitors

A scheme for "fingerprinting" of Actinomyces pyogenes strains based on their production of (P-typing) and the sensitivity to (S-typing) bacteriocin-like substances has been developed. P-typing and S-typing of 42 A. pyogenes cultures with a set of 9 micrococcal and staphylococcal species as indicator strains and 9 streptococcal species as bacteriocin producer strains revealed 10 P types and 7 S types, respectively. The bacteriocin "fingerprinting" procedure might provide a means for subdividing A. pyogenes and may find application in epidemiological studies.

Isolation and characterization of an extracellular protease of Actinomyces pyogenes

An extracellular protease from Actinomyces pyogenes ATCC 19411 could be isolated by ion exchange chromatography with DEAE cellulose and high performance gel filtration (FPLC) on Superose 12 prep grade. The purified enzyme had a relative molecular mass of approximately 37,000 Dalton, a pH optimum at 7.5, a temperature optimum at 50 degrees C, and a Km value of 2.2 mg/ml with azocasein as substrate. The enzyme activity was clearly inhibited by PMSF, EDTA, the metal ion Zn++ and only weakly by Cd++ and Co++. Preparative isoelectric focussing of the culture supernatant from A. pyogenes ATCC 19411 revealed one major point with protease activity at pH 5.2.

Characterization of extracellular neuraminidase produced by Actinomyces pyogenes

Extracellular neuraminidase from Actinomyces pyogenes could be isolated by ammonium sulfate precipitation, ion exchange chromatography with DEAE cellulose and gel filtration on Ultrogel ACA 54. The purified enzyme had a molecular weight of approximately 50,000 Dalton, a pH optimum at pH 6.0, a temperature optimum at 55 degrees C and a Km value of 1.4 X 10(-4) mol/l with N-acetyl-neuraminlactose as substrate. Preparative isoelectric focussing of the culture supernatant revealed neuraminidase activity mainly at pH 6.5. The enzyme activity was not influenced by metalions or EDTA.

Actinomyces pyogenes bacteraemia in a patient with carcinoma of the colon

A patient with carcinoma of the colon adherent to the pelvis developed Actinomyces pyogenes bacteraemia after uterine curettage but recovered with antibiotic treatment. This organism is a Gram-positive cocco-bacillus, beta-haemolytic when growing on blood agar and reactive with Lancefield group G antiserum. These features could easily lead to its misidentification as a streptococcus. Reports of human infection with A. pyogenes are summarised.