Bacteria associated with Respiratory tract : Part II

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1 Bacteria associated with Respiratory tract : Part II VETERINARY BACTERIOLOGY AND MYCOLOGY ( ) 1 st semester 2012 Assistant Prof. Dr. Channarong Rodkhum Department of Veterinary Microbiology Faculty of Veterinary Science Chulalongkorn University Channarong_CU@hotmail.com Channarong.R@Chula.ac.th

2 Department of Veterinary Microbiology Faculty of Veterinary Science Chulalongkorn University Mycoplasma sp. Veterinary Bacteriology and Mycology ( ) Academic year 2012 Channarong Rodkhum D.V.M. (Hons), Ph.D.

3 Mycoplasma sp. General characteristics Family Mycoplasmataceae Class mollicutes Lack of cell wall synthyesis Resistant to -lactam antibiotics Gram stain is not a part of identification process Sensitive to digitonin (Deleterious effect on sterols) Widely distribute in humans, mammals, birds, repiles, and fish Associated mainly with respiratory, arthritic and Genito-urinary tract diseases excepted for hemotrophic mycoplasma or hemoplasma (Erythrocytes s parasite)

4 Mycoplasmataceae Pure culture Diene s stain Positive Digitonin Sensitive Urease production Resistant Acholeplasma Negative Wall-defecient bacteria (Bacterial L-forms) Positive Ureaplasma Negative Mycoplasma

5 Characteristics The genus Mycoplasma More than 100 species Diameter µm Simple structure (Ribosome + DNA) bound by a trilaminar cytoplasmic membrane (Sterols, phospholipids, and proteins) Most are facultative anaerobe, except for Mycoplasma pneumoniae strict aerobe Grow slowly (4-5 days on agar)

6 Mycoplasma colony

7 Diseases and Epidemiology Human Mammal Reptile Fish

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9 Mycoplasma in avian Mycoplasma synoviae Mycoplasma iowae Mycoplasma meleagridis Mycoplasma gallisepticum Chicken, Turkey : Synovitis Turkey : Embryo mortality Turkey : air sacculitis Turkey : Sinusitis Mycoplasma synoviae infect joint in chicken

10 Mycoplasma in Swine Mycoplasma hyopneumoniae Mycoplasma hyorhinis Mycoplasma hyosynoviae Enzootic pneumonia Polyarthritis, polyserositis Polyarthritis Confluent consolidation of cranioventral lung lobes

11 Mycoplasma in Ruminant Mycoplasma agalatiae Goat, sheep : Contagious Mycoplasma alkalescens Cattle : arthristis, mastitis Mycoplasma bovigentitalium Cattle : infertility, mastitis Mycoplasma bovis Cattle : arthritis, mastitis, pneumonia, abortions, abscesses, otitis media, genital infections Mycoplasma boviculi Cattle : conjunctivitis Mycoplasma dispa Cattle : Bronchiolitis Mycoplasma mycoides spp. mycoides Cattle, Domestic water buffalo : (small-colony type) Contagious bovine pleuropneumonia

12 Mycoplasma in Dogs and Cats Mycoplasma cynos Mycoplasma canis Mycoplasma felis Mycoplasma gatae Dog : Pneumonia Dog : Urinary tract infection Cat : Conjunctivitis, pneumonia Cat : Chronic arthritis, tenosynovitis

13 Pathogenicity and Pathogenesis Damage host cells Virulence factors Cytadhesins : attaches to cilia of respiratory epithelial cells Hydrogen peroxide production : induce oxidative stress in host cells Membrane-bound phospholipases : release cytolytic lysophospholipids disrupting host cell membranes Modulins : induce cytokine synthesis inflammation Immune evasion : antigenic variation Chronicity

14 Diagnosis (1) : Culture and identification of bacteria : laborious Time consuming, low sensitivity Isolation of mycoplasmas from clinical specimens does not confirm their etiological status. Isolation media : contain sterols, vitamins, amino acids and Adenine dinucleotide Grow at 37 C, produce colony after 4-5 days incubation

15 Diagnosis (2) : Colony size : mm in diameter, dense elevated centers (fried-egg appearance) Diene s stain : differentation mycoplasmal colony from cell wall-deficient bacteria (L-form) Immunologic methods Molecular biologic methods : PCR, DNA probe

16 Prevention of some Mycoplasma sp. Infection in animal Bacterin vaccine

17 Bordetella sp. Veterinary Bacteriology and Mycology ( ) Academic year 2012 Channarong Rodkhum D.V.M. (Hons), Ph.D. Department of Veterinary Microbiology Faculty of Veterinary Science Chulalongkorn University

18 ORGANISM: Genus: Bordetella Species: pertussis, parapertussis, bronchiseptica GENERAL CONCEPTS: responsible for respiratory disease in humans and animals. B. pertussis, in particular, is the etiologic agent of pertussis, more commonly known as whooping cough. B. parapertussis causes a milder form of pertussis. B. bronchiseptica mostly affects animals but occasionally humans. B. bronchiseptica causes kennel cough, a highly contagious upper respiratory problem in dogs. Bordetella sp. cause disease by producing toxins that impair mucociliary function in the respiratory tract.

19 DISTINCTIVE PROPERTIES: Gram negative coccobacilli. produce a capsule and are strict aerobes. Only B. bronchiseptica is motile. Bordetella sp. possess the heat stable endotoxin LPS and produce several exotoxins. These include: 1. Pertussigen: A 120 kd protein, an ADP-ribosyltransferase that interferes with the transfer of signals from cell surface receptors. Pertussigen is also involved in mediating attachment to respiratory epithelia. 2. Adenylate cyclase toxin: this toxin increases camp levels, inhibiting immune effector cell functions. 3. Tracheal cytotoxin: This toxin causes ciliostasis and extrusion of ciliated epithelia. 4. Dermonecrotic toxin: This heat labile substance causes tissue destruction. 5. Filamentous hemagglutinin: involved in attachment to host cells.

20 Transmission occurs by direct contact, or via respiratory aerosol droplets, or fomites. Pathogenesis (I) Bacteria initially adhere to ciliated epithelial cells in the nasopharynx interaction with epithelial cells is mediated by a series of protein adhesins (filamentous haemaglutinin, pertactin, fimbriae, and pertussis toxin) some attachment to immune effector cells. The initial phase of infection produces symptoms similar to those of the common cold, and during this period, large numbers of bacteria can be recovered from the pharynx. Thereafter, the bacteria proliferate and spread further into the respiratory tract, where the secretion of toxins causes ciliostasis and facilitates the entry of bacteria to tracheal/bronchial ciliated cells.

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22 Pathogenesis (II) One of the first toxins to be expressed is tracheal cytotoxin derived from peptidoglycan. Tracheal cytotoxin itself is able to reproduce paralysis of the mucociliary escalator, inhibition of DNA synthesis in epithelial cells. One of the most important of the regulated toxins is adenylate cyclase toxin, which aids in the evasion of innate immunity. Immune cell functions are then inhibited in part by the resulting accumulation of cyclic AMP.

23 Diagnosis : Bacterial culture and identification PCR

24 Prevention : Pertussis vaccine A canine bordetella vaccine is available. While it will not completely prevent dog from getting the disease, it will significantly decrease the severity of the symptoms.

25 Family Pasteurellaceae HAP : Haemophilus sp. Actinobacillus sp. Pasteurella sp.

26 Department of Veterinary Microbiology Faculty of Veterinary Science Chulalongkorn University Haemophilus sp. Veterinary Bacteriology and Mycology ( ) Academic year 2012 Channarong Rodkhum D.V.M. (Hons), Ph.D.

27 General Concept : Haemophilus is a genus of Gram-negative pleomorphic, coccobacilli bacteria Family Pasteurellaceae The genus includes commensal organisms along with some significant pathogenic species such as H. influenzae a cause of sepsis and bacterial meningitis in young children and H. somnus, the causative agent of pneumonia in cattle. All members are either aerobic or facultatively anaerobic.

28 Species : H. parasuis (cause Glässer's Disease in swine) H. somnus (cause cattle pneumonia) : commonly found in upper respiratory tract, prepuce and vagina of cattle H. aegyptius H. aphrophilus H. avium H. ducreyi H. felis H. haemolyticus H. influenzae H. parainfluenzae H. paracuniculus H. parahaemolyticus H. pittmaniae etc.

29 Diagnosis : typically cultured on blood agar plates as all species require at least one of the following blood factors for growth: hemin (factor X) and/or nicotinamide adenine dinucleotide (factor V) Chocolate agar is an excellent Haemophilus growth medium as it allows for increased accessibility to these factors. Alternatively, Haemophilus is sometimes cultured using the "Staph streak" technique: both Staphylococcus and Haemophilus organisms are cultured together on a single blood agar plate. In this case, Haemophilus colonies will frequently grow in small "satellite" colonies around the larger Staphylococcus colonies because the metabolism of Staphylococcus produces the necessary blood factor by-products required for Haemophilus growth.

30 Department of Veterinary Microbiology Faculty of Veterinary Science Chulalongkorn University Actinobacillus sp. Veterinary Bacteriology and Mycology ( ) Academic year 2012 Channarong Rodkhum D.V.M. (Hons), Ph.D.

31 General concept : Actinobacillus is a genus of Gram-negative immotile and nonspore-forming oval to rod-shaped bacteria parasites or pathogens in mammals, birds, and reptiles. It is a member of the Pasteurellaceae family. The bacteria are facultatively aerobic or anaerobic capable of fermenting carbohydrates (without production of gas) reducing nitrates Actinobacillus pleuropneumoniae (App) causes swine pleuropneumonia

32 Species A. actinomycetemcomitans A. arthritidis A. capsulatus A. delphinicola A. equuli A. hominis A. indolicus A. lignieresii A. minor A. muris A. pleuropneumoniae ( App ) A. porcinus A. rossii A. scotiae A. seminis A. succinogenes A. suis A. ureae App cells

33 Lesions of Actinobacillus pleuropneumoniae infection in swine

34 Prevention of App. in Swine Good management Vaccine Inactivated vaccine,swine pleuropneumonia

35 Department of Veterinary Microbiology Faculty of Veterinary Science Chulalongkorn University Pasteurella sp. Veterinary Bacteriology and Mycology ( ) Academic year 2012 Channarong Rodkhum D.V.M. (Hons), Ph.D.

36 General Concept : Family Pasteurellaceae Gram-negative Most members live as commensals on mucosal surfaces of birds and mammals, especially in the upper respiratory tract Other Pasteurellaceae cause gingivitis and chancroid in humans and many others are important veterinary pathogens Pasteurellaceae are typically rod-shaped, and are a notable group of facultative anaerobes They can be distinguished from the related Enterobacteriaceae by the presence of oxidase absence of flagella.

37 General concept : Many Pasteurella species are zoonotic pathogens, and humans can acquire an infection from domestic pet bites. P. multocida is the most frequent causative agent in human Pasteurella infection. Pasteurella occurs in many cats' mouths, a large percentage of dog mouths, and frequently in rabbits. This is in perfectly normal and otherwise healthy animals. The common occurrence of the bacteria is a reason to be medically proactive and defensive (antibacterial treatments are often necessary) if a bite occurs. transmitted through nasal secretions. P. multocida can survive several days in water or moist areas.

38 Species : P. aerogenes P. anatis P. avium P. bettyae P. caballi P. canis P. dagmatis P. gallicida P. gallinarum P. granulomatis P. langaaensis P. lymphangitidis P. mairii P. multocida P. oralis P. pneumotropica P. skyensis P. stomatis P. testudinis P. trehalosi P. ureae P. volantium

39 In rabbits : P. multocida is also known cause of morbidity and mortality in rabbits, and the predominant syndrome is upper respiratory disease. In swine : Progressive Atrophic Rhinitis (PAR) describes a specific disease where the nose tissues permanently atrophy. It is caused by specific toxin producing strains of P. multocidia In cattle : bovine respiratory disease (BRD), enzootic calf pneumonia In poultry : Fowl cholera Diseases P. multocida infections in poultry and pigs are not pathognomonic and can be mixed up with other respiratory system infections characterized by upper respiratory tract inflammations, pneumonia, airsacculitis, and septicemia

40 Mannheimia haemolytica (Pasteurella haemolytica): the predominant cause of bovine pneumonic pasteurellosis, or shipping fever. Various virulence factors allow M. haemolytica to colonize the lungs and establish infection.

41 Virulence factors : leukotoxin (LKT) Lipopolysaccharide Adhesins capsule, outer membrane proteins various proteases. Virulence and Pathogenesis (I) : The effects of LKT are species specific for ruminants LKT can activate bovine leukocytes to undergo respiratory burst and degranulation and stimulate cytokine release from macrophages and histamine release from mast cell LKT can inhibite PAM activities LKT induces formation of transmembrane pores and subsequent oncotic cell necrosis.

42 Virulence and Pathogenesis (II) : leakage of products of respiratory burst and other inflammatory mediators into the surrounding pulmonary parenchyma and so give rise to fibrinous and necrotizing lobar pneumonia. adhesins, capsule, outer membrane proteins, and proteases assist in pulmonary colonization, evasion of immune response

43 Acute pneumonia in goats and sheeps caused by Mannheimia haemolytica

44 Rhinitis in pigs very common and can be caused by a variety of bacteria and irritant substances. Rhinitis may result in damage of the nasal turbinates. Atrophic rhinitis: moderate conchae atrophy

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