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5 - Bacteria Pathogens
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5 - Bacteria Pathogens

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  • 1. Major Pathogens: Bacteria
  • 2. Bacterial Pathogens Pathogens = disease-causing bacteria • Gram-positive cocci • Gram-negative cocci • Gram-positive rods • Gram-negative rods • Mycobacteria • Walls too thick to stain for gram • Mycoplasma • Spirochetes • Obligate intracellular parasites
  • 3. Gram-Positive Cocci Staphylococcus (grape-like clusters) Genus includes 33 species mostly harmless Likes high osmotic pressure, low moisture Staphylococcus aureus Facultative anaerobe, golden yellow pigmented colonies Skin infections (abscesses), impetigo Conjunctivitis Food poisoning Toxic shock syndrome Staphylococcal scalded skin syndrome (SSSS) Nosocomial sepsis
  • 4. Staphylococcus aureus
  • 5. MOT and Pathology  Normal habitat: Skin, nose, vagina  33% are carriers  Exotoxins:  Enterotoxins: Food poisoning  Toxic shock syndrome toxin  Scalded skin syndrome toxin
  • 6. Food poisoning 1-6 hoursIntoxication: infection by digestion
  • 7. Impetigo Skin infection caused by Staphylococcus aureus
  • 8. Scalded Skin Syndrome Staphylococcus aureus Usually in babies
  • 9. Diagnosis, Prevention, Treatment  Coagulase-positive; Catalase-positive  MSA plate  Hand-washing; proper food storage; frequent tampon changes  Penicillin (80% resistant)  Oxacillin; (methicillin)  Vancomycin Rabbit plasma
  • 10. Streptococcus = cocci that grow in chains Streptococcus pyogenes (Group A - GAS) Pharyngitis (Strep. throat) Scarlet fever Rheumatic fever Necrotizing fasciitis (flesh-eating disease) Puerperal sepsis.
  • 11. MOT and Pathology  Droplet infection: Pharyngitis/ Strep throat  Exotoxins:  Scarlet fever  Erythematous rash over body  Hemolytic enzymes: necrotizing fasciitis  Capsule  Composed of hyaluronic acid  Evades phagocytosis
  • 12. Streptococcal Pharyngitis
  • 13. Scarlet Fever Rash caused by Streptococcus pyogenes Streptococcus epidemitis: normal flora (non pathogenic) on the body that is opportunistic, can cause UTI’s.
  • 14. Necrotizing Fasciitis due to Streptococcus pyogenes http://emedical-help.com/necrotizing-fasciitis-flesh-eating-disease/ Puerperal Sepsis: “Child Fever”
  • 15. Diagnosis, Prevention, Treatment  Culture swabs from lesions  Beta-hemolytic on Blood Agar plates  Antibody titer  Proper hygiene during wound care  Prolonged treatment with penicillin (Rheumatic fever patients)  Penicillin  Debridement of infected tissues
  • 16. Streptococcus agalactiae/dysgalactiae (Group B) Neonatal meningitis and sepsis Streptococcus mutans Dental caries Streptococcus viridans Bacterial endocarditis Streptococcus pneumoniae Pneumonia Adult bacterial meningitis
  • 17. Streptococcus agalactiae/dysgalactiae (Group B) Neonatal meningitis and sepsis MOT and Pathology Normal vaginal flora: Can colonize genital tract and cause neonatal meningitis and sepsis Prevention Prophylactic Ampicillin (mother) And Treatment Penicillin (newborn)
  • 18. Streptococcus mutans = facultative anaerobe Dental caries (cavities) • Metabolizes sugars to lactic acid  decays enamel • Excretes a sticky polysaccharide for adhesion to surfaces and each other  plaque • Biofilm protects from extreme and changing environment of the mouth • Biofilm plaque best removed mechanically (floss) • Oral Hygiene is important • Treatment: Fill cavities
  • 19. Streptococcus viridans  Bacterial endocarditis  Prevention  Prophylactic amoxicillin
  • 20. Streptococcus pneumoniae  Pneumonia, meningitis  MOT  Droplet  Diagnosis  Direct sputum culture  Prevention  Vaccination  Treatment  Penicillin or erythromycin
  • 21. Gram-Negative Cocci Neisseria: aerobic, found in mucous membranes, release endotoxins • Neisseria gonorrhea Ophthalmic gonorrhea Genital gonorrhea • Neisseria meningitidis: Adult bacterial meningitis (Meningococcal meningitis)
  • 22. Pus Discharge in Gonorrhea
  • 23. N. gonorrhea MOT & Pathology  STD/STI  PID (pelvic infl. Disease)  Diagnosis  Culture (Gram- negative intracellular diplococci  Prevention  Safe sex  Treatment  Ceftriaxone
  • 24. Neisseria meningitidis  MOT & Pathology  Droplet: meningitis  Stiff neck, fever, headache, vomiting  Diagnosis  CSF Culture  Prevention  Vaccine  Treatment: Penicillin, Rifampicin
  • 25. Gram-Positive Bacilli • Spore-forming Gram-positive Bacilli Bacillus anthracis: Anthrax Bacillus cereus: Food poisoning Clostridium botulinum: Botulism Clostridium tetani: Tetanus (lockjaw) Clostridium perfringens: Gas gangrene Clostridium difficile: Pseudomembranous enterocolitis
  • 26. B. anthracis MOT & Pathology  Spores (facultative anaerobe)  Diagnosis  Culture  Prevention  PPE  Prophylaxis  Vaccine (only for risk groups)  Treatment  Ciprofloxacin
  • 27. Bacillus cereus: soil dwelling aerobe  MOT and Pathology  Spores ingested: food poisoning  Enterotoxin  Prevention  Proper food handling  Treatment  self-limiting
  • 28. Clostridium botulinum: anaerobe  MOT and Pathology  Food contaminated with spores  Vegetables, Honey  Neurotoxin: very toxic  Acetylcholine blocked: paralysis of face/limbs  Prevention  Proper sterilization of food before canning  Treatment: Antitoxin
  • 29. Clostridium tetani
  • 30. C. tetani: anaerobe  MOT and Pathology  Spores enter wound  Exotoxins  Muscle spasms, lockjaw  Diagnosis  Direct observation  Prevention  Vaccine: DTaP/ Tdap  Treatment: Tetanus immune globulin; antibiotics
  • 31. Clostridium perfringens: anerobe
  • 32. C. perfringens  MOT & Pathology  Spores enter wound after trauma  Toxins and gas  Tissue necrosis  Diagnostics  Foul smell  Crepitation  Prevention  Clean wound thoroughly  Treatment: Penicillin & Wound debridement
  • 33. Clostridium difficile Pseudomembranous enterocolitis  MOT & Pathology  Fecal-Oral – usually nosocomial  Broad-spectrum antibiotics allow C. difficile to flourish  Exotoxins: severe diarrhea  Treatment  Stop the antibiotic  Re-hydration therapy  Prevention  Aseptic technique
  • 34. Non-spore-forming Gram-positive Bacilli Corynebacterium diphtheriae Diphtheria Listeria monocytogenes Gastroenteritis
  • 35. Corynebacterium diphtheriae • MOT & Pathology • Sore Throat, fever, trouble breathing • Droplet infection • Toxin: heart/ kidney damage • Diagnosis • Throat exam • pseudomembrane • Prevention • DTaP contains toxoid • Treatment: Antitoxin, Penicillin
  • 36. Listeria monocytogenes • MOT & Pathology • Ingestion of contaminated food • Psychrophilic • Spontaneous abortion • Prevention • Proper food handling • Pasteurization • Treatment • Ampicillin
  • 37. Gram-Negative Bacilli Enteric Gram-negative Bacilli: facultative anaerobes Escherichia coli: UTI, gastroenteritis (Traveler’s diarrhea), hemolytic-uremic syndrome. Salmonella enteritidis: Gastroenteritis Salmonella typhi: Typhoid fever Shigella dysenteriae: Gastroenteritis Campylobacter jejuni: Gastroenteritis Helicobacter pylori: Gastric ulcer, carcinoma of the stomach Vibrio cholerae: Cholera Vibrio parahemolyticus: Food toxicity
  • 38. Enterobacteriaceae • Large family of gram-negative rods • Found primarily in colon • Common features • Facultative anaerobe, non-spore forming
  • 39. Escherichia coli • MOT & Pathology • Normal Flora of human colon • UTI (most common cause) • Fecal-oral • O157:H7 toxin: hemolytic-uremic syndrome • Treatment • Quinolones • Self limiting • Prevention • Remove urinary catheters, ♀ wipe front to back, water and food handling, handwashing
  • 40. Salmonella enteritidis • MOT & Pathology • Fecal-oral (human and animal) • Eggs and poultry • Reptiles • Treatment • Self-limiting • Rehydration therapy • Prevention • Public health • Personal hygiene
  • 41. Salmonella typhi • MOT & Pathology • Fecal-oral (human only) • Typhoid fever • Treatment • Ciprofloxacin • Prevention • Personal hygiene • Vaccine available (for travelers only)
  • 42. Shigella dysenteriae • MOT & Pathology • Fecal-oral (human only) • ID50 =10 • The four Fs: fingers, flies, food, and feces • Treatment • Rehydration/Ciprofloxacin • Prevention • Public health • Personal hygiene
  • 43. Campylobacter jejuni • MOT & Pathology • Fecal-oral (human and animal) • Food or water contamination • Treatment • Ciprofloxacin • Prevention • Public health • Personal hygiene
  • 44. pH – Neutrophiles & Acidophiles As with temperature, bacteria have minimum, optimum and maximum pH ranges. Neutrophiles • Protozoans and most bacteria have an optimum pH range of 6.5 to 7.5. • pH range of human organs and tissues. Acidophiles • Most fungi & some bacteria grow best in acid niches. • Example: Chemoautotrophic bacteria that live in mines and in water that runs off from waste rock around mines. • Obligate acidophiles have to live in an acidic environment. • Acid-tolerant Microbes will survive in an acid environment, but do not prefer that. Images: HelicobacterPylori : Electron micrograph of H. pylori possessing multiple flagella. Yutaka Tsutsumi, M.D. Professor Department of Pathology Fujita Health University School of Medicine Helicobacter pylori • Gram-negative, microaerophilic, and acidophilic bacterium. • Infects various areas of the stomach and duodenum. • Many cases of peptic ulcers, gastritis, duodenitis, and perhaps some cancers are caused by H. pylori infections. • However, many who are infected do not show any symptoms. • Helicobacter spp. only known microorganisms to thrive in highly acidic environment of stomach.
  • 45. Helicobacter pylori • MOT and Pathology – Ingestion, produce ammonia – Gastric ulcer – Carcinoma • Treatment – Antibiotics • Prevention – None
  • 46. pH : Cholera (Alkalinophiles) Alkilinophiles • Can live in water as well as soil with pH’s around 11.5 (14 is max alkilinity)! • Example: Vibrio cholera (Cholera) will grow outside the body at a pH of 9.0. • Infectious gastroenteritis caused by the bacterium Vibrio cholerae. • Transmission occurs through ingesting contaminated water or food. • Major reservoir for cholera long assumed to be humans, but considerable evidence exists that aquatic environments can serve as reservoirs of the bacteria. • Gram-negative bacterium that produces cholera Alkilinophiles • Action on mucosal epithelium lining of the small intestine responsible for the characteristic massive diarrhea. • One of the most rapidly fatal illnesses known. Progresses from first liquid stool to shock in 4 to 12 hours, with death quickly following without rehydration treatment.
  • 47. Vibrio cholerae • MOT and Pathology – Fecal-oral – Contaminated H2O – Enterotoxin – Watery stools • Treatment – Rehydration therapy • Prevention – Public health – Personal hygiene
  • 48. Vibrio parahemolyticus • MOT and Pathology – Lives in warm seawater – Ingestion of raw/undercooked seafood • Treatment – Self limiting (three days) • Prevention – Proper refrigeration and cooking of seafood
  • 49. Nosocomial Gram-negative Bacilli Klebsiella pneumoniae: Pneumonia and UTI Proteus vulgaris: UTI especially hospital acquired Pseudomonas aeruginosa: Burn sepsis and UTI and more Serratia marcescens: Burn sepsis
  • 50. Klebsiella pneumoniae • MOT & Pathology – Respiratory tract and intestinal tract – Droplet – Catheter • Treatment – Antibiotics • Prevention – Prompt removal of urinary catheter
  • 51. Proteus vulgaris • MOT & Pathology – Human colon – Soil and H2O – Highly motile, colonizes urethra, leads to ascending infection • Treatment/Prevention – Antibiotics – Prompt removal of catheters
  • 52. Nail Infection with Pseudomonas aeruginosa
  • 53. Psuedomonas aeruginosa • MOT & Pathology – Soil, H2O, NF colon/skin – Aqueous solutions – Withstand disinfectants – Burn wounds – Purulent blue-green discharge/fruity odor • Treatment/Prevention – Antibiotics – Highly resistant – Sterilization
  • 54. Burn Infection with Pseudomonas aeruginosa
  • 55. Respiratory Gram-negative Bacilli Bordetella pertussis: Whooping cough Haemophilus influenza: Pediatric meningitis, Otitis media, sinusitis, and epiglottitis Legionella pneumophilia: Pneumonia
  • 56. Bordetella pertussis • MOT & Pathology – Whooping cough – Droplet infection – Complications: pneumonia or CNS • Treatment – Erythromycin • Prevention – DTaP
  • 57. Haemophilus influenza • MOT & Pathology – Droplet infection – Type B encapsulated (Hib) – Meningitis, otitis media, sinusitis, epiglottitis • Treatment/Prevention – Ceftriaxone – Hib vaccine (Hemophilus influenza type B)
  • 58. Legionella pneumophilia • MOT & Pathology – Inhalation of aerosols from infected H2O – Grows best in warm waters – Air conditioners, water-cooling towers – Legionnaire’s disease: Pneumonia • Treatment/Prevention – Erythromycin – Reduce aerosols – Water treatment
  • 59. Arthropod-borne disease: Yersinia pestis: Plague Borelia burgdorferi: Lyme disease (Spirochete) Rickettsia rickettsii: Rocky mountain spotted fever (Obligate intracellular parasite)
  • 60. Yersinia pestis • Plague (black death) • Killed one quarter of the population of Europe in the middle ages • Fleas transmit • Bubos: inflammed lymphnodes • Droplet = pneumonic plague
  • 61. Lyme disease Causative agent: Borrelia burgdorferi • Reservoir: Deer • Vector: Ticks • First symptom: Bull's-eye rash • Second phase: Irregular heartbeat, encephalitis • Third phase: Arthritis
  • 62. Obligate Intracellular Parasites • Chlamydia trachomatis: NGU, pelvic inflammatory disease (PID), eye infection • Rickettsia rickettsii: Rocky mountain spotted fever (RMSF) • Rickettsia prowazeki: Typhus • Lack ability to produce enough ATP to grow independently
  • 63. Chlamydia trachomatis • Most common bacterial STI in USA • Eye infection, fomites, birth canal • PID • Infertility • Erythromycin
  • 64. Rickettsia rickettsii: Rocky mountain Spotted Fever • Dogs and rodents are reservoir • Tick-borne transmission • Tetracycline • Insect repellent/tick inspection
  • 65. Rickettsia prowazeki • Typhus – Fever, chills, rash, meningitis, death • Louse-borne • Disease of poverty and wartime • Control of body lice
  • 66. Syphilis: Spirochaete Infection
  • 67. Treponema pallidum • STI • Chancres • Neurosyphilis: 10%; dementia • Penicillin to treat; safe sex to prevent
  • 68. Mycobacteria • Aerobic acid-fast bacilli • Mycobacterium tuberculosis: • Pulmonary TB – Droplet – 90% asymptomatic: Skin Test – Hemoptysis • Mycobacterium avium: indistinguishable from TB – Widespread in environment
  • 69. Mycobacterium leprae • Leprosy • Direct contact • Nasal or skin secretions • Replicates in skin • Anesthesia, bone re-absorption • Loss of digits or tip of nose • Antibiotics • Isolation of patients
  • 70. Mycoplasma • Smallest bacteria • Lack cell wall • Fluorescent stains to visualize • Mycoplasma pneumoniae: walking pneumonia – Droplet infection – Common on campuses – May be self-limiting or require antibiotics
  • 71. Question Staphylococcus and Streptococcus can be easily differentiated in a lab by which of the following? a) Cell shape b) Gram stain reaction c) Growth in high salt concentration d) Ability to cause disease e) Glucose fermentation

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