Taxonomy of gram-positive bacteria High G+C content in DNA Low G+C content in DNA Actinobacteria Firmicutes Molicutes • Actinomyces • Bacillus • Mycoplasma • Streptomyces • Clostridium • Ureaplasma • Nocardia • Lactobacillus • Acholeplasma • Corynebcaterium • Listeria • Mycobacterium • Erysipelothrix • Micrococcus • Staphylococcus • Propionibacterium • Gardnerella • Streptococcus • Bifidobacterium • Enterococcus Actinomyces • Hypha-like filamentous cells • Facultatively anaerobic/anaerobic, • Commensal of skin • Grow slowly, prefer anaerobic condition A. israelii – actinomycosis – cervicofacial (poor oral hygiene, invasive dental procedure) thoracic, abdominal, pelvic, CNS -abscesses • Treatment – penicillin, erythromycin, clindamycin prolonged therapy (4-12 m) Nocardia • Strict aerobic rods • Cell wall – mycolic acids, arabinosa, galactose, meso-diaminopimelic acid weakly acid –fast • N. asteroides, N. brasiliensis • Bronchopulmonary disease (immunocompromised patiants) • Cutaneous infections – mycetoma, lymphocutaneous i., cellulitis, abscesses • Treatment – sulfonamides, 6 w., surgery Corynebacterium • Cell wall with short mycolic acids, meso-DAP, arabinose, galactose • Metachomatic granules • Aerobic, facultativly anaerobic, non motile • Associated wit human disease: • C. diphtheriae, C. jejkeium, C. urealiticum, Corynebacterium diphtheriae • Diphtheria – bacteria infected with β-phage • Diphtheria toxin – AB toxin, inhibits protein synthesis by inactivating EF-2 • Pediatric disease – respiratory diphtheria, • Sore throat, low-grade fever, exudative pharyngitis. Exudate evolves into thick pseudomembrane cover tonsils, uvula and palate • Cutaneous diphtheria – ulcers covered by grayich membrane • Treatment – diphthreia antitoxin • Prevention – vaccination - toxoid Mycobacterium • Non motile, non spore forming, aerobic rods • Acid-fast • Grow slowly – generation time 12-24 h group organisms Tuberculosis complex M. tuberculosis, M. bovis, M. leprae, M. africanum Runyon group I (slow-rowing, M. kansasii, M. marinum, M. simiae photochomgens) Runyon group II (slow growing, M. szulagai, M. scrofulaceum, M. xenopi scotochomogens) Runyon group III (slow growing M. avium, M. genavense, M. nonchomegens) haemophilum, M. malmoense Runyon group IV (rapid growers) M. abscessus, M. chelonae, M. fortuitum, M. mucogenicum Cell wall of mycobacteria Mycobacterium tuberculosis • Cord-factor - 6,6-trehalose- dimycolate- Toxic for mitochondria, inhibits neutrophils migration • Wax D, polypeptids – type IV Löwenstein-jensen agar hypersensitivity Microscopy – Ziehl-Neelson stain Tuberculosis • - infection by inhalation – close contact • Primary tuberculosis Infect alveolar macrophages – survive phagocytosis, attraction of new macrophages activate infalammation and forming tubercule, colagen fibres enclosing infected macrophages and lung cells – caseous necrosis inside - cavities • Secondary tuberculosis – reactivation of M. tuberculosis after latency from tubercules Disseminated tuberculosis – dissemination by infected macrophages, infection of bone marrow, spleen, kidneys, spinal cord Epidemiology: 10% of infectred people develop primary tuberculosis and 10% secondary tuberculosis during the life 10,6 mil infected people - 2016 No 1 cause of death in HIV positive patient • Diagnosis – tuberculin test – screening Chest X- ray, microscopy of sputum, cultivation, Quantiferon (IFNγ) • Treatment: multi-drug regimens and prolonged therapy • INH (isoniazid) + etambutol + pyrazinamide + rifampin for 2 months • INH + rifampin for 4-6 months • For susceptible mycobacteria, non HIV patients • MDR-TBC (multidrug resistant) Resistant to INH or rifampicin Second line anti-TB drugs: Streptomycin, amikacin, viomycin, capreomycin, fluoroquinolones, cycloserin, thionamid • XDR-TBC (extensivly drug resistant) With additional resistance to anti-TB drugs from second line drugs • Prevention • Vaccination – BCG Calmette-Guérine attenuated strain of M. bovis • Prevent the dissemination of M. tuberculosis, not prevent the pulmonary disease in adults • Effective in children • Not suitable for HIV-exposed neonates • Development of new vaccines Major TB vaccines in clinical trials Mycobacterium leprae • Strict inracellular parasite • The most slowly growing bacteria • Multiply only in the human cells • Chronic infection of skin and peripheral nerves Disease: leprosy 1. Tuberculoid form – strong cellular immune response 2. Lepromatous from – strong antibody response – more infectious Tuberculoid leprosy (TT) Lepromatous leprosy (LL) Transmission – person-to-person, close contact, inhalation of infectious aerosol Treatment: rifampicin and dapson 6 month, lepromatous leprsoy + clofazimine min. 12 monts Mycobacterium avium complex • M. avium, M. avium - intercellulare, M. kansasii • Resistant to common anti-TB drugs • Tuberculosis-like infection, lymphadenitidis • Immunocompromised patient • Propionibacterium acnes – produce propionic acid, skin commensal, anaerobe, cause acne in adolescents and young adults, erytromycin, clindamycin – for severe cases • Gardnerella vaginalis – commnensal of vaginal microbiota, opportunistic agent of vaginal inf. (metronidazole) • Micrococcus – oporthunistic pathogen • Bifidobacterium – anaerobe, GIT commensal, probiotic properties Bacillus • Aerobic, facultativly anaerobic • Spore forming • Mostly motile – peritrichal • ATB producers: B. polymyxa – polymxin B. colistinus – colistin B. subtilis – bacitracin B. brevis – gramicidin, tyrocidin Bacillus anthracis • infect mostly herboivors • transmission to human: skin – cutaneous anthrax, necrotic eschar ingestion – gastrintestinal anthrax (rare) inhalation – inhalation anthrax – mediastinal lymph nodes - 2 stages, progress to shock and death within 3 days of initial symptoms unless treatment: ciprofloxacin, penicillin, doxycycline prevention – vaccination of animals Virulence factor: capsule – poly-D-glutamic acid toxins: 1. protective antigen PA63 – forms chanel in host cell to transport other toxins to the cell 2. edema factor EF – adenylate cyclase, inrease cAMP levels – edema 3. lethal factor – zinc metalloprotease , cleaves MAPK, lead to cell death Bacillus cereus • ubiquitous in soil • food conatminated with spores (rise, meat) • cereolysin, phospholipase C • gastroenteritis • heat-stable, proteolysis-stable enterotoxin – emetic form • heat-labile enterotoxin– diarrheal form • ocular infectons – rapid destruction of eye (48h) (vancomycin, clindamycin, ciprofloxacin) Clostridium • strict anaerobic, spore forming, • ubiquitous in soil, water, part of microbiota in the GIT of animals and humans Clostridium tetani • motile, round terminal endospores • tetanospasmin – released after cell lysis, A-B toxin, A- light chain (zinc endopeptidase) B – heavy chain (binding to sialic acid receptors) • spastic paralysis - muscles contractions • generalized/localized, neonate tetanus • treatment – debridement of primary wound, metronidazole, passive immunization • vaccination – toxoid, every 10 years Clostridium botulinum • botulinum toxins A – G, A, B, E, F • A-B toxin – A light chain zinc endopeptidase, B heavy chain protect A chain and binds to sialic acid receptors of motor neurons • remains in at the neuromuscular junction, block realese of acetylcholin – flaccid paralysis • heat-labile – 60°C 10 min • soil and water samples – food contamination • foodborne botulism – canned foods • infant botulism (< 1year) – food contaminated with spores (honey) – bacteria survive in GIT • blurred vision, dilated pupils, dry mouth, constipation, bilateral weakness of peripheral muscles, death attributes to respiratory paralysis • treatment – ventilatory support, metronidazole, botulinum antitoxin • no antibodies after diseas Clostridium perfringens • 5 types A to E according the toxins production • toxins: α, β, ε, ι, δ, θ, κ, λ, μ, ν, enterotoxin, neuraminidase • soft-tissue infections: cellulitis, suppurative myositis, myonecrosis (gas gangrene), food poisoning - gastroenteritis, necrotizing enteritis • treatment – surgical debridement, high-dose penicillin, hyperbaric oxygen Clostridium difficile • colonize the intestines of portion of healthy population • post-antibiotic diarrhea pseudomembranous colitis • enetrotoxin (toxin A) – attract neutrophils, disruption of tight cell junction – diarrhea • cytotoxin (toxin B) – actine depolymerization • treatment: metronidazole, vancomycin Listeria monocytogenes • facultatively anaerobic rod • grow in range 1 °C to 45 °C, motile at RT • facultative intracellular pathogen • feces of animal, humans, decaying vegetables • food contamination (meat, soft cheese, turkey, raw vegetables) • transplancental transmission to fetus virulence factors: listeriolysin O, phospholipase C, internalins, actin-direct motility protein ActA patient disease Neonatal disease Early – granulomas in multiple organs (in utero) Late – meningitis, meningoencephalitis Healthy adults Influenza-like disease, gastroenteritis sometime cell-mediated Meningitis, bacteremia immune defect patients treatment: ampicillin, aminoglycosides, TTC, - resistant to cephalosporins Erysipelothrix rhusiopathiae • pleomorphic rods, microaerophilic, • animal pathogen (swine, turkey) – butcher, farmers, veterinarians are at risk • Disease: erysipelas – localized skin infection (septic form endocarditis) • Treatment: penicillin Staphylococcus • gr. staphylé – bunch of grapes • Catalase positive, spherical shape, facultative anaerobic coagulase positive coagulose negative Staphylococcus aureus Staphylococcus epidermidis