弧菌+厌氧菌

nullnull Vibrio Cholerae p.141 (Classical biotype and El Tor biotype) I. Basic Properties 1. Morphology: Short and fine, Curved rod, G－, Single flagella, active motility 2. Culture: Aerobic , pH 9, TCBS agar 3. Resistance: Lower resistant to heat, acid, dryingnullV. Cholerae morphologynull4.Antigenic structures and classification 1). O antigen: more than 200, mainly O1 and O139 serogroups: O1 and O139 non-O1/non-O139 2). Biology: Claasic biotype: 1817~1923(1st~6th) El Tor biotype: in 1961(7th) O139 serotype: from 1992 (8th?) {{nullII. Pathogenesis and Immunity V. Cholerae habitat only adherence to the intestinal epithelial cellular surface, not enter into cells and blood, multiply there and release Cholera toxin (CT) and endotoxin. pathogenicity only for humannull Cholera enterotoxin(CT) B Subunit A Subunit (A1、A2) ↓ ↓A1 through bind to the receptor Cell membrane of mucous (GM1) ↓activation ATP ↓ cAMP↑ ↓ severe diarrhea (over secretion )G protein ---GsnullClinical findings: nausea, vomiting, diarrhea “rice water” stool rapid loss fluid and electrolytes mortality rate: 60% without treatment <1% with treatment Immunity: gastric acid anti-toxin: very strong, reinfection is rare!nullIII. Diagnostic laboratory test. 1. rapid diagnosis 1). Smear and staining 2). Immobilize test 3). Fluorescin bacteria ball test SPA coagglutination: for toxinsnull2. Cultures 37℃ Peptone broth Smear pH8-9 6—8 h 37℃ Smear agar plate(TCBS) Colony pH8-9 10-24 h identification.nullIV. Prevention and Treatment 1. Prevention separate the patients. 4f , water, personal hygiene Vaccine: im only for 6 months study on oral vaccine, subunit vaccine 2. Treatment supplement of fluid, electrolytes antibiotics: tetracycline nullV. parahaemolyticusMain character: halophilic---35% NaCl Disease: food poisoning Treatment: gentamycin or SMZ Chapter 18Chapter 18anaerobic bacteriap. 164nullGrowth under without oxygen environment According to forming of spore or not, anaerobes could be classified into: clostridium Non-spore-forming anaerobesCharacteristics:Section 1Section 1ClostridiumnullMost of them anaerobe strictly ，G+ Spore diameter is bigger than body，so just like a spindle; resistance is very strong Except C. perfringens，all with flagellum，without capsule Most are saprophytes: including 154 species Fewer are pathogen: mainly 3 speciesGeneral properties nullnullI. C．tetaninullIt is the pathogen to tetanus Hyperreflexia, muscle spasms, and spastic paralysis are the most clinic findings mortality is about 30%~50%Biological characteristicsBiological characteristicsMorphology and staining slender，flagellum, no capsule Just like drum-stick after spore-forming G+ Culture and biochemical reaction Anaerobe strictly β-hemolytic on blood plate No-ferment sugars，no-catalytic proteins nullnullnullresistance Very strong as spore Keep living after 75~80°C 10 min Destruction after 100°C 1h Surviving many years in dry soil or dustPathogenesis and immunityPathogenesis and immunityPathogenic conditions:Pathogenic conditions:Dependent on the production of toxins low invasiveness (not invasive organism)，reproduction at wound local Easy to form anaerobe environment Deeply wound Contamination strong (soil or dust) Delayed treatment Co-infected with aerobesPathogenic materials:Pathogenic materials:Tetanolysin: sensitivity to oxygen Tetanospasmin: coded by plasmid Main pathogenic material Belong to neurotoxin， LD50 to mice =0.015ng Lethal dose to human <1µg protein，heat labile；destructed by proteaseTetanospasmin:Tetanospasmin: structure: Peptide with MW 150 kD A strain， 50 kD; B strain, 100 kD, -S-S- bond between strains B strain---bind to GM receptor A strain with toxicitynullAction mechanism:Action mechanism:Binds to receptor on the presynaptic membrane： B strain Motor neurons Enter cell and forming vesicle Migration: By the retrograde axonal transport system to the cell bodies of the neurons to the spinal cord and brain stemnullTarget: Inhibitory neurons (cells) Action: Blocking the release of inhibitory neurotransmitter, such as glycine and gama-aminobutyric acid nullHigh affinity to spinal cord and brain stem Not to be neutralized by anti-toxin after binding to the receptorClinical findingsClinical findingsIncubation time 4-5 days to several weeks Classic findings: muscular spasms Mouth cannot be opened The patient is fully conscious, and pain may be intense. Death usually result from interference with the mechanics of respiration. nullImmunityImmunityMainly depend on antitoxin Could not acquired enough immunity after illness Effective prophylactic---immunization with tetanus toxoid.Microbiological diagnosisMicrobiological diagnosisResting on the clinical picture and a history of injury No use of C. tetani examinationPrevention & Treatment Prevention & Treatment Proper care of wounds contaminated soil, etc Prevention---immunization with tetanus toxoid. Suspected wounds---intramuscular adminis- tration TAT (tetanus antitoxin） Patient: antitoxin and antibiotics antitoxin—as earlier as possible, sufficient dosage Ⅱ. C．perfringensBiological characteristicsBiological characteristicsMorphology and stainingMorphology and stainingLarge G+ rods: 0.6-2.4×1.3-19µm Spores adjacent to the body end, smaller than body, not regularly present No flagellum With capsule in vivonullCulture:Culture:Not strictly anaerobe；optimal temperature: 42°C; generation time only 8 min Blood agar plate，double hemolytic zone On egg yolk plate+anti-αtoxin， “Nagler reaction” Sugar fermentation: In milk media，“stormy fermentation”+Typing:Typing:According to α,β,ε,ιtoxins, C. perfeingens is classified into A, B, C, D and E 5 toxic types Type A is the most commonpathogenesispathogenesisPathogenic materials:Pathogenic materials: Produce invasive infection Produce more than 10 exotoxins，part of them belonging to exo-cyto-enzymesMajor and minor toxinsMajor and minor toxinsnullαtoxin: Produced by type A mainly lecithinase Major activity in gas gangrene β、ε、ιtoxins: Tissue necrosis and increased vessel divulge nullEnterotoxin: Protein (MW 35 kD)，heat labile, 100°C instant destruction Treated with trypsine, toxicity increase 3 times Whole molecular integrate into cell membrane marked hypersecretion intense diarrhea Super antigenDiseasesDiseases1. Gas gangrene Caused by type A of C. perfringens, spores reach tissue either by contamination of traumatized areas or from intestinal tract Short incubation time，1-3days Fement carbohydrates gas distention of tissue Lecithinase, collagenase, hyaluronidase, DNase, etc tissue necrosisnullCrepitation in the subcutaneous tissue and muscle, Foul-smelling discharge, Rapidly progressing necrosis, fever, hemolysis, toxemia, shock, and deathnull2. Food poisoning Ingestion of large numbers of clostrdia, more than 108 Onset of diarrhea, usually without vomiting or fever Last only 1-2 daysMicrobiological diagnosisMicrobiological diagnosisDirect check under microscope Materials from wounds, pus, tissue Large Gram-positive rods Fewer WBC Presenting other bacterianullIsolation and animal test Inoculation on blood plate or meat-glucose media，biochemical reaction Animal test: 0.5~1ml iv mice，10 min kill the mice, then swollen at 37 oC 5-8 h For food poisoning，if >105/g in food or 106/g in feces, diagnostic significancePrevention and TreatmentPrevention and TreatmentPrevention Early cleansing contaminated wounds, surgical debridement, and Administration drugs, eg, PNC Not be relid on antitoxin Treatment surgical debridement, excision of all devitalized tissue Antibiotics Antitoxin, especially anti-αtoxin Hyperbaric oxygen nullⅢ. C．botulinumBiological characteristicsBiological characteristicsShort Gram-positive rods Having terminal spore, just like spoon With flagellum, without capsule anaerobe strictly，easy to culture Toxins: A~G 7 types (antigen) type A most common, no cross protection heat labile, 100oC, 1min pathogenesispathogenesisPathogenic materials Botulinum toxin: belong to neurotoxin lethal dose to human---0.1µg Structure and action just as tetanospasminAction mechanismsAction mechanismsToxin Absorbed from the gut, bind to the presynaptic membrane of motor neurons of the peripheral nervous system, inhibit the release of acetylcholine, result flaccid paralysis Not enter central nervous systemnullType A and E cleave SNAP-25 (synaptosomal-associated protein, 25000) type B cleave VAMP (vesicle-associated membrane protein) Type C and type D coded by phages，others coded by chromosomediseasesdiseasesFood posoning Ingestion of the toxin food，non-bacteria infection Different according to the area After 18-24 h visual disturbances, inability to swallow, speech difficulty death occur from respiratory paralysisnullInfant botulism Most <6 months，ingestion toxin-contaminated food poor feeding, weakness, and signs of paralysis Death rate about 1%-2%Diagnositic laboratory testsDiagnositic laboratory testsspecimen Leftover food Heated 80°C, 10 min examination Toxin check: animal test (ip mice) including neutralization testPrevention & TreatmentPrevention & TreatmentFood monitoring, boiled for 20 min before consumption Diagnosis earlier Administration antitoxin to A, B and E Supportive therapy nullⅣ. C. Difficile Antibiotic-associated diarrhea Pseudomembraous colitis