Corynebacterium


Download 9.59 Mb.
Sana10.01.2019
Hajmi9.59 Mb.
#59042



Corynebacterium

  • Corynebacterium

  • C. diphtheriae

  • Disease

  • Diphteria

  • Opportunistic infections by other Corynebacterium species (dipheroids)



Club-shaped also V- or L-shaped

  • Club-shaped also V- or L-shaped

  • Beaded appearance

  • Methachromatic granules (Albert staining)

  • Nonmotile

  • no capsule

  • Facultative anaerobic.

  • Classified in CNM group.













Gravis

  • Gravis

  • Mitis

  • Intermedius

  • Belfanti





Common diphtheria (Nasopharyngitis)

  • Common diphtheria (Nasopharyngitis)

  • Incubation period of 2–5 days.

  • Fibrinous exudate “pseudomembrane”

  • Sore throat, fever, Enlargement of neck lymph nodes and neck edema. Irregulatory of cardiac rhythm, difficulties with vision, speech and swallowing.

  • Corrosion of myelin sheaths in the central and peripheral nervous system leading to degenerating motor control









Cutanous diphtheria

  • Cutanous diphtheria

  • (a secondary infection)

  • Antibody production: Blocking the fragment B and so preventing entry into the cell.



Humans the only natural host

  • Humans the only natural host

  • C. diphtheriae reside in the upper respiratory tract

  • Transmitted by airborn droplet

  • Infection at the site of a pre-existing skin lesion



Invasivness

  • Invasivness

  • Exotoxin



Cord factor

  • Cord factor

  • A glycolipid inhibits eukaryotic cell oxidation.

  • Nuraminidase

  • Removes N-acetyl nuraminic acid from musine membranes.



Fragment B. Binding of the toxin

  • Fragment B. Binding of the toxin

  • Fragment A. Enzymatic activity



Nicotinamide adenine dinucleotide phosphate (NAD)

  • Nicotinamide adenine dinucleotide phosphate (NAD)



Intradermal injection (0.1 mL):

  • Intradermal injection (0.1 mL):

  • I. Cause inflammation (4-7 days later): No antitoxin in patient

  • II. No inflammation: Antitoxin is present (Immune person)



Microscopic observation (differentiation from streptococcal and vansant nasopharyngitis)

  • Microscopic observation (differentiation from streptococcal and vansant nasopharyngitis)

  • Isolating the organism

  • Loffler’s medium

  • a tellurite plate

  • Tinsdal medium

  • Demonstrating toxin production

  • Animal inoculation

  • Eleck test

  • ELISA

  • PCR to detect tox gene



Tracheostomy  in children (to prevent croup)

  • Tracheostomy  in children (to prevent croup)

  • Antitoxin

  • 20000-100000 unit (Intra muscular)

  • Penicillin or erythromycin



Vaccination

  • Vaccination

  • A combination of diphtheria toxoid, tetanus toxoid, and killed pertusis organism.

  • Given at 2, 4 an 6 months of age, with a booster at 1 and 6 years of age and then each 10 years afterward. (DPT or DT)

  • The toxoid is prepared by treating the exotoxin with 0.3% formaldehyde.



Small rod like “chinese character”

  • Small rod like “chinese character”

  • No capsule, Facultative aerobic.

  • Tumbling movement. Movement in 25 c

  • Growing in 4c

  • Small and smooth colony on blood with a narrow zone of beta-hemolysis

  • Biochemical tests: Fermentation, Catalase + Oxidase +



Meningitis and sepsis in

  • Meningitis and sepsis in





The organism is distributed worldwide in animals, plants and soil.

  • The organism is distributed worldwide in animals, plants and soil.

  • Transmission to human by contact with animals or their feces

  • unpasteurized milk

  • contaminated vegetables.

  • Endogenously from gasterointestinal tract.



E-cadherin

  • E-cadherin



Microscopic observation: Diphtheroids

  • Microscopic observation: Diphtheroids

  • Isolation by culture:

  • Blood and CSF samples on blood agar

  • Colonies: Small, gray colonies with a narrow zone of beta hemolysis



Penicillin

  • Penicillin

  • Resistant are rare



Bacillus (Aerobic)

  • Bacillus (Aerobic)

  • B. antheracis, B.cereus

  • Clostridum (Anaerobic)

  • C. tetani, C. botulinum, C. perfringens, C. difficile



Disease

  • Disease

  • Anthrax (common in animal but rare in humans).



A large rod with square ends.

  • A large rod with square ends.

  • Frequently in chains

  • A unique anti-phagocytic capsule is composed of D-glutamate.

  • Non-motile (other members of the genus are motile.)













Spores persist in soil for years. Infection from animal products (hides, bristles and wool), contact with sick animal.

  • Spores persist in soil for years. Infection from animal products (hides, bristles and wool), contact with sick animal.

  • Portals of entry: skin, mucous membranes, and respiratory tract.



A typical lesion: A painless ulcer with black, necrotic eschar. Local edema.

  • A typical lesion: A painless ulcer with black, necrotic eschar. Local edema.

  • Untreated cases progress to bacteremia and death.

  • Woolsorter’s disease (pulmonary anthrax) is a life threatening pneumonia (by inhalation of spores).









Invasiveness

  • Invasiveness

  • Exotoxin

  • Anthrax toxin, has 3 components:

  • Protective antigen

  • Lethal factor: In the presence of protective antigen is rapidly fatal for mice. The action is unknown

  • Edema factor (an exotoxin): An adenylate cyclase dependent on protective antigen for its binding and entry into the cell.



Samples: Exudate, Blood, sputum.

  • Samples: Exudate, Blood, sputum.

  • Direct smear: Large rods in chains. Spores not seen in smears of exudate.

  • Culture and biological/biochemical tests (Sensitivity to penicillin (String of pearls test), Fermentation, gelatin hydrolysis, Motility)

  • No serological tests are useful





Preventing soil contamination

  • Preventing soil contamination

  • Sterilizing dead animals and animal products .

  • Protecting persons at risk of exposure with special clothes.

  • Vaccination with cell-free vaccine for persons at high risk.



Penicillin

  • Penicillin

  • No resistant strain isolated



Motile

  • Motile

  • No capsule

  • Saprophyte



Disease

  • Disease

  • Food poisoning

  • Rare infections: Meningitis, Osteomyelitis, …

  • Transmission

  • Spores on grains survive during steaming and rapid frying. Spore germinated when rice is kept warm.

  • Portal of entry is the gastrointestinal tract.



B. cereus produces 2 enterotoxins. Their actions is unclear.

  • B. cereus produces 2 enterotoxins. Their actions is unclear.

  • Clinical findings

  • Emetic syndrome

  • A short incubation period (4 hours) with nausea and vomiting similar to staphylococcal food poisoning.

  • Diarrheal syndrome

  • Involves a long incubation period (18 hours) with diarrhea and resembles clostridial gastroenteritis.



Not usually done

  • Not usually done

  • Treatment

  • No antibiotic is given. Only symptomatic treatment

  • Prevention

  • Grains (specially rice) should not be reheated



An aerobic bacteria

  • An aerobic bacteria

  • Clostridiums tetani

  • Peritricus flagella

  • Terminal spore

  • Disease

  • Tetanus (Lockjaw)



Incubation period: 4-5 days – several weeks

  • Incubation period: 4-5 days – several weeks

  • Violent muscle spasms in the site of infection and then jaw)

  • Lockjaw (trismus) due to rigid contraction of the jaw muscles, which prevents the mouth from opening: a characteristic known as “risus sardonicus”’.

  • Low blood pressure

  • Respiratory failure











Spores are widespread in soil.

  • Spores are widespread in soil.

  • The portal of entry is a wound site.

  • Germination of spores is favoured by necrotic tissue and poor blood supply in the wound.



Tetanus toxin (tetanospasmin)

  • Tetanus toxin (tetanospasmin)

  • It is carried intra-axonally (retrograde) to the central nervous system, where it binds to ganglioside receptors and blocks release of inhibitory mediators (e.g. glycine, Gamma-aminobutiric acid) at spinal synapses leading to hyper reflection and spastic paralysis.





History of wound and clinical picyure

  • History of wound and clinical picyure

  • There is no microbiologic or serologic diagnosis.

  • Organisms are rarely isolated from the wound site.

  • Treatment

  • Antitoxin does have a low effect

  • Penicillin

  • Respiratory support

  • Muscle relaxants



Immunization with toxoid in childhood (2, 4, 6, 12 months ages) and every 10 years thereafter.

  • Immunization with toxoid in childhood (2, 4, 6, 12 months ages) and every 10 years thereafter.

  • When trauma occurs deeply:

  • 1. Wound should be cleaned and debrided.

  • 2. Tetanus toxoid booster should be given.

  • 3. Tetanus immune globulin should be given.

  • 4. Penicillin administered.





In soil ---> Alkaline vegetables/meat ---> canned/vacuum-packed ---> Spore germination ---> Toxin production ---> ingestion

  • In soil ---> Alkaline vegetables/meat ---> canned/vacuum-packed ---> Spore germination ---> Toxin production ---> ingestion



Botulinus toxin

  • Botulinus toxin

  • Observing from the gut ---> Carrying via the blood to peripheral nerve synapses ---> Blocking release of acetylcholine ---> Paralysis







Disease: Gas Gangrene / Food Poisoning

  • Disease: Gas Gangrene / Food Poisoning

  • Transmission

  • Pathogenesis

  • Clinical findings

  • Laboratory diagnosis

  • Treatment

  • Prevention



Soil, vegetative cells are members of normal flora in colon and vagina.

  • Soil, vegetative cells are members of normal flora in colon and vagina.

  • Is associated with war wounds.



Alpha toxin: Lecithinase

  • Alpha toxin: Lecithinase

  • Glycogen metabolism: Gas in tissues: Crepitation

  • Treatment

  • Penicillin

  • Wounds should be debrided

  • H2O2





Smear of tissue and exudate samples: large positive rods.



Transmission: Soil and food. Survives cooking and grows to large numbers in reheated food, especially meat.

  • Transmission: Soil and food. Survives cooking and grows to large numbers in reheated food, especially meat.

  • Pathogenesis: An enterotoxin (a protein in the spore coat)

  • Clinical findings:

  • Incubation: 8-16 hours, then watery diarrhea with cramps and little vomiting. Resolves in 24 hours.



Treatment: Symptomatic – No antimicrobial drugs

  • Treatment: Symptomatic – No antimicrobial drugs

  • Prevention: cooking well



Disease

  • Disease

  • Transmission

  • Pathogenesis

  • Clinical Finding

  • Laboratory diagnosis

  • Treatment

  • Prevention



Antibiotic-associated pseudomembranous colitis

  • Antibiotic-associated pseudomembranous colitis

  • Transmission

  • It is a part of normal flora of gasterointestinal tract (3%)





Antibiotic (Clindamycin and ampicillin) supress drug-sensitive normal flora, allowing C. difficile to multiply: produce toxin.

  • Antibiotic (Clindamycin and ampicillin) supress drug-sensitive normal flora, allowing C. difficile to multiply: produce toxin.

  • Toxin mechanism is unclear



Diarrhea

  • Diarrhea

  • Pseudomembranes (yellow-white plaques) on the colonic mucosa.

  • Visualised by sigmoidoscopy.



Toxin detectable in stool affecting on cell cultured cells.

  • Toxin detectable in stool affecting on cell cultured cells.

  • Inhibition of cytotoxicity by specific antibody.



Withdrew the antibiotic

  • Withdrew the antibiotic

  • Oral vancomycin instead along with fluids.




Download 9.59 Mb.

Do'stlaringiz bilan baham:




Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©fayllar.org 2022
ma'muriyatiga murojaat qiling