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HOST MICROBE INTERACTIONS A. SYMBIOSIS - LIVING TOGETHER 1. MUTUALISM - BOTH BENEFIT E.G.,

HOST MICROBE INTERACTIONS A. SYMBIOSIS - LIVING TOGETHER 1. MUTUALISM - BOTH BENEFIT E.G., TERMITES INGEST CELLULOSE (NO N 2 ) PROTIST (TRYCHONYMPHA) IN GUT DIGESTS CELLULOSE TO ACETATE, CO 2 , AND H 2 TERMITES LOVE ACETATE BACTERIUM IN PROTIST CONVERTS:

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HOST MICROBE INTERACTIONS A. SYMBIOSIS - LIVING TOGETHER 1. MUTUALISM - BOTH BENEFIT E.G.,

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  1. HOST MICROBE INTERACTIONS A. SYMBIOSIS - LIVING TOGETHER 1. MUTUALISM - BOTH BENEFIT E.G., TERMITES INGEST CELLULOSE (NO N2) PROTIST (TRYCHONYMPHA) IN GUT DIGESTS CELLULOSE TO ACETATE, CO2, AND H2 TERMITES LOVE ACETATE BACTERIUM IN PROTIST CONVERTS: C02 AND H2 TO ACETATE AND ATMOSPHERIC N2 TO NH3 USED BY PROTIST AND TERMITE E.G, RUMINANTS APPRECIATE!!!

  2. 2. COMMENSALISM - ONE BENEFITS AND THE OTHER NEITHER BENEFITS NOR IS HARMED E.G., HUMAN MOUTH, OROPHARYNX AND NON-PATHOGENIC NEISSERIA SPECIES LACTOBACILLI – LACTOBACILLUS LACTIC ACID FERMENTATION OF SUGARS • 3. PARASITISM - ONE BENEFITS, THE OTHER IS HARMED • E.G., STREPTOCOCCUS PNEUMONIAE • ANY OTHER PATHOGEN

  3. B. CONTAMINATION:MICROORGANISMS PRESENT C. INFECTION - MULTIPLICATION OF PARASITE ON OR IN BODY D.DISEASE - DISTURBANCE OF NORMAL STATE – NORMAL FUNCTIONS CAN NOT BE PERFORMED E. PATHOGEN - ORGANISM CAPABLE OF CAUSING DISEASE F. PATHOGENICITY: CAPACITY TO CAUSE DISEASE

  4. G. VIRULENCE - DEGREE OF INTENSITY OF DISEASE, DEGREE OF PATHOGENICITY HIGHLY VIRULENT – ROTAVIRUS HUMAN AND ANIMAL DIARRHEA INFECTIOUS DOSE = 10 - 100s WEAKLY VIRULENT CANDIDA ALBICANS • RESERVOIRS – SOURCES: • ANIMAL BODIES, FOOD, WATER, SOIL I. NOSOCOMIAL INFECTIONS – HOSPITAL & HEALTH CARE FACILITY ACQUIRED INCLUDE: SURGICAL WOUND INFECTIONS CATHETERS e.g., URINARY TRACT IMMUNOSUPPRESSED PATIENTS

  5. NORMAL FLORA NORMAL MICROBIOTA – NORMAL FLORA - MICROFLORA – MIX OF ORANISMS REGULARLY FOUND AT ANATOMICAL SITE INCLUDES COMMENSALS, PARASITES (PATHOGENS AND OPPORTUNISTIC PATHOGENS) A. SKIN - BARRIER - STAPHYLOCOCCUS AUREUS STAPHYLOCOCCUS EPIDERMIDIS CANDIDA ALBICANS B. EYE –LYSOZYME – HYDROLYZES PEPTIDOGLYCAN

  6. C. UPPER RESPIRATORY TRACT (NOSE, NASOPHARYNX) PATHOGENSCARRIERS – TRANSIENT OR CHRONIC STREPTOCOCCUS PYOGENES NEISSERIA MENINGITIDIS OPPORTUNISTIC PATHOGENS PNEUMOCYSTIS CARINII D. MOUTH, THROAT PATHOGEN - STREPTOCOCCUS MUTANS DENTAL CARIES OPPORTUNISTIC PATHOGEN - CANDIDA ALBICANS

  7. E. STOMACH pH ~ 2 <10 ORGANISMS/ML GASTRIC FLUID HELICOBACTER PYLORI - ULCERS OTHERS PASS THRU (IN FOOD) F. INTESTINE STRICT AND FACULTATIVE ANAEROBES ENTERIC ORGANISMS - GRAM NEGATIVE RODS WHICH GROW IN INTESTINE OF WARM-BLOODED ORGANISMS

  8. EXAMPLES OF PATHOGENS & NON-PATHOGENS • INTESTINE - • EXAMPLES OF PATHOGENS & NON-PATHOGENS • ESCHERICHIA COLI - MOSTLY NON-PATHOGENS; SOME PATHOGENIC STRAINS SHIGELLA SONNEI, SHIGELLA DYSENTERIAE SALMONELLA ENTERICA (MANY STRAINS/SEROVARS) CAMPYLOBACTER JEJUNI ENTEROCOCCUS FAECALIS COLIFORMS: GRAM NEGATIVE, FACULTATIVELY ANAEROBIC, RODS, NON-SPORE FORMING; ESCHERICHIA, ENTEROBACTER, KLEBSIELLA

  9. F. INTESTINE, CONTINUED – ENTEROHEMORRHAGIC E. COLI STRAINS (EHEC) CAUSE HEMOLYTIC UREMICSYNDROME - HUS HEMOLYTIC ANEMIA – REDUCED RBCs - HEMOLYSIS THROMBOCYTOPENIA-LOW PLATELET COUNT ACUTE RENAL (KIDNEY) FAILURE SHIGA-LIKE TOXIN, BLOODY DIARRHEA, TOXIN ENTERS BLOOD, ATTACHES TO GLOMERULI ENDOTHELIUM, DAMAGES BLOOD VESSELS IN KIDNEY (& OTHER REGIONS OF BODY), ACTIVATES PLATELETS PLATLETS BIND ENDOTHELIUM, OBSTRUCT ARTERIOLES/CAPILLARIES, RBCs DESTROYED AS THEY PASS (HEMOLYSIS) LEADS TO ACUTE RENAL FAILURE REDUCED BLOOD FLOW TO OTHER VITAL ORGANS ISCHEMIA – RESTRICTION IN BLOOD SUPPLY

  10. G. UROGENITAL TRACT COMMENSALS - LACTIC ACID BACTERIA OPPORTUNISTIC PATHOGENS CAUSE VAGINITIS CANDIDA ALBICANS – TRICHOMONAS VAGINALIS – A PROTOZOAN CYSTITIS - BLADDER INFLAMMATION– UTI - NORMALLY STERILE, BUT OPPORTUNISTIC PATHOGENS CAUSE DISEASE IF THEY GAIN ENTRY ENTEROCOCCUS FAECALIS, ENTEROCOCCS FAECIUM REAL PATHOGEN - UROPATHOGENIC E COLI

  11. INFECTIOUS DISEASES A. DISEASE – CLASSIFICATION INFECTIOUS INHERITED DEGENERATIVE NEOPLASTIC NUTRITIONAL DEFICIENCY IDIOPATHIC PATHOLOGY - STUDY OF DISEASE ETIOLOGY - CAUSE OF DISEASE

  12. B. KOCH'S POSTULATES 1. SAME ORGANISM PRESENT IN EVERY CASE OF DISEASE 2. ORGANISM MUST BE ISOLATED FROM DISEASED HOST AND GROWN IN PURE CULTURE 3. INTRODUCING PURE CULTURE INTO SUSCEPTIBLE HOST CAUSES SAME DISEASE 4. ORGANISM MUST BE ISOLATED FROM THE DELIBERATELY-INFECTED HOST AND GROWN AGAIN IN PURE CULTURE

  13. C. TRANSMISSION 1. CONTACT a. DIRECT - PERSON TO PERSON E.G., SEXUAL CONTACT HEPATITIS B, C, D, INFLAMMATION OF LIVER b. lNDIRECT - CONTAMINATED OBJECT – FOMITE E.G., NEEDLE SHARING, HIV, HEPATITIS VIRUSES c. DROPLETS - SNEEZING, COUGHING – TRAVEL LESS 1 METER, E.G., COMMON COLD

  14. TRANSMISSION, CONTINUED 2. VEHICLES - FOOD, WATER, AIRBORNE DUST OR DROPLET NUCLEI, BLOOD a. FOOD – WATER i. SHIGELLA – SHIGELLOSIS ii. SALMONELLA – SALMONELLOSIS iii. VIBRIO – CHOLERA iv. HEPATITIS VIRUS A - INFECTIOUS HEPATITIS HEPATITIS VIRUS E b. DUST, DROPLET NUCLEI i. MYCOBACTERIUM TUBERCULOSIS ii. HISTOPLASMA CAPSULATUM – HISTOPLASMOSIS iii. MEASLES, CHICKEN POX c. BLOOD: HEPATITIS B - SERUM HEPATITIS, C, D

  15. TRANSMISSION, CONTINUED 3. VECTORS a. MECHANICAL VECTOR – FLIES b. BIOLOGICAL VECTOR – DEER TICKS - DEER, MICE, DOGS,CATS - PEOPLE e.g. LYME DISEASE – BORRELIA BURGDORFERI

  16. D. SPREAD IN POPULATIONS 1. ENDEMIC - ALWAYS PRESENT HISTOPLASMA CAPSULATUM 2. EPIDEMIC: SUDDEN INCREASE IN OCCURRENCE – VIBRIO CHOLERAE 3. PANDEMIC - WORLD-WIDE EPIDEMIC - HIV 4. SPORADIC - LOCALIZED OUTBREAK HANTA VIRUS

  17. E. SPREAD IN INDIVIDUALS PRIMARY INFECTION –INFLUENZA SECONDARY INFECTION - PNEUMONIA FROM STAPHYLOCOCCUS AUREUS

  18. F. INCIDENCE: NUMBER OF NEW CASES OF A DISEASE WITHIN A SPECIFIED PERIOD OF TIME INCIDENCE IS A RATE. OFTEN EXPRESSED IN A GIVEN LOCATION (CITY, STATE, US) AND OFTEN EXPRESSED PER UNIT OF POPULATION, SUCH AS PER 100,000. G. PREVALENCE TOTAL NUMBER OF CASES OF DISEASE WITHIN A POPULATION AT ANY TIME OR WITHIN ANY DEFINED PERIOD OF TIME.

  19. H. UNIVERSAL PRECAUTIONS - RULES FOR HANDLING INFECTIOUS MATERIAL OR POTENTIALLY INFECTIOUS MATERIAL TO PREVENT TRANSMISSION OF DISEASE SEE PAGE 160 E.G., WEAR GLOVES IF HANDLING BLOOD OR BODY FLUIDS NO EATING, SMOKING, DRINKING IN LAB.

  20. I. PEOPLE INFECTIOUS FOR OTHERS? • INFECTED WITH SYMPTOMS YES • INFECTED WITHOUT SYMPTOMS YES • CARRIERS – TRANSIENT YES • CARRIERS - CHRONIC YES • THOSE WITHOUT PATHOGENS NO

  21. J. DISEASES CAUSED BY EXOTOXINS 1. DIPHTHERIA CORYNEBACTERIUM DIPHTHERIAE LYSOGENIC WITH PROPHAGE 2. BOTULISM CLOSTRIDIUM BOTULINUM LYSOGENIC 3. TETANUS CLOSTRIDIUM TETANI – PLASMID 4.GAS GANGRENE CLOSTRIDIUM PERFRINGENS –PLASMID 5. ANTHRAX - BACILLUS ANTHRACIS TWOPLASMIDS

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