Classify dermatophytes

 

                                           Classify Dermatophytes

It is a group of filament us fungi that infect superficially I,e skin , hair and Nail. The clinical condition known as dermatophytes popularly called Toenia and ring worm.

                   It is classified in 3 genera:-

1. Trichophyton 2. Mycosporum 3. Epidermophyton based on Macroconidia.

Ø  In lesion dermatophytes appear as Hyphae and Artherospore. In culture on SDA medium shows characteristic colonies consisting of septate hyphae and two types of asexual spare, Microconidia ansd Macroconidio.

1. Trichophyton:- Colonies may be powdery, velvety or waxy. Microconidia are ab undant and are arranged in cluster along the hyphae and macroconidia are relatively scanty. They are generally elongated with blunt end. Some species shows spiral hyphae and racket mycelium.

2. Mycosporum:- Colonies are velvety or powdery with white to brown pigmentation. Microconidia are relative scanty. Macroconidia are large multicellular and spindle shaped structure, infect hair and skin.

3. Epidermophyton:- Colonies are powdery and greenish yellow in colour. Microconidia are absent. Microconidia are multinucleated. Pear shaped are typically arranged in cluster attached to the skin and nail.

       Pathogenicity:- Dermatophytes grow only on the Keratinized tissue of the layer of skin. They do not penetrate into the living tissue. The fingal product give rise to local inflammation or a HSR.

          Lab diagnosis:- The routine method of diagnosis is by the examination of lesions in KOH mounts.

        i) Scrapping are taken from the edge of ring worm and mount in KOH. Heated and shows branched septate hyphae microscopically.

       ii) Examination of infected hair in UV light, Ectothrix and Endothrix with arthrospore.

      iii) Demonstration of fugus in nail mount in KOH for 1 day for clearing.

      iv) Special Identification by inoculation on SOA and colonies shows may appear in only 1-3 weeks.

Name of different gram positive anaerobic bacteria

 

Name of different gram positive anaerobic bacteria. Discribe lab diagnosis of C. tetani.

  Ans :- Gram positive anaerobic bacteria are divided into two groups :-

                  Group 1- Causing wound Infection

ü  Clastridium perfringes

ü  Clastridium oedematies

ü  Clastridium bifermentation

ü  Clastridium histolyticum

ü  Clastridium tetani

                   Group 2- Causing Intestinal lesions.

ü  Perfringens type A2

ü  Enterotoxin

ü  Neeroticans

ü  Botulinum

v  Lab diagnosis of Tetanus :- Laboratory test are not frequent to diagnosis of tetanus. It is detected by sign and symptom , muscles , spam , pain etc . Laboratory test only help in confirmation.

                                        Lab diagnosis may be made by demonstration of c-tetani by microscopy , culture or by animal inoculation. Microscopic  examination shows drumstick bacilli in wound. The bacilli may be present in wound without tetanus and cant differentiate between clastridium tetani or clastridium tetanomorphum or clostridium sphenoides.

          1. The material from  necrotic depth of wound , then from wound swab is inoculated on one half of blood agar plate . Clostridium tetani produce swarinig in 1-2 days of growth. Which may detected by comparision.

          2. The material is also inoculated in three tubes containing cooking meat broth. One of the which is heated to 80 ˙c for 15 minutes ,. The 2^nd for 5 minutes and third is not heated.

         → Heating is done to kill vegetative bacteria, while leaving undamaged tetani spore.

                Tube 1:- Give finding of spore containing bacilli.

                Tube 2:- Give finding of non- spore containing bacteria.

                Tube 3:- Is related to non- clostridial organism.

                   →  Tube is Incubated at 37˙c for 4 days and sub culture daily on one half of blood agar.

        3. Toxigenicity test :- It is done by innoculation  of 2-4 day Robert sun cooked meat culture in mouse through tail. If tetanus is present, stiffness of tail appear after 6 hour and the animal dies after 2 days.

v  Sign and symptom :- Spasm of jaw muscles by stiffness of the neck, diffically in swallowing and stiffiness of abdominal muscles.

     Other Sign:- fever , sweating , elevated blood pressure &rapid heart rate. Spasm after occur, which may be last for several minutes and certain for 3-4 weeks.

Cholera

 

Describe Lab diagnosis of cholera

          1. Dark ground illumination examination of stool for darting motility. Diagnosis is confirmed by adding antiserum to the sample which abolish the motility .

           2. Cultural isolation from stool on tellurite gelatin agar or any other special medium particularly , alkaline peptone water and thiosulphate eitrate bile salt.

            3. By chemical reaction :- Cholera Vibrio ferments glucose , maltose , mannite and sucrose with acid production only.

             4. Cholera Red Reaction :- This is rapid method of diagnosis bacteria grown in peptone water is mixed with 1 drop of Conc Hzso4 media turns red if cholera is present.

              5. GRERG test for hemolysis :- It is done for differentiating cholera from EL – TORS , EL – TOR is haemolytic and cholera is not.

               6. Agglutination Test :- For antigenic classification into oguva , in ova and hikajima.

              7.  Phage typing by phage – 4 :- Cholera is not killed by phage – 4.

              8. String Test :- Bacterial suspension + 0 ˙5 % sodium deoxycholate – Clera the turbidity + mucoid-+ ve.

Different types of biological wast generated in hospitals

 

 Hospital waste include the following: -

1.  General Refuse like house hold garbage:

        Includes paper, glass, textiles and kitchen waste.

2. Waste from medical environment :-  Cluster , casts , disposiable clotting , banges , disposable syring , drip bags , residues from hospital Laboratory and research units.

          3. Infectious waste :-  Microbiological waste like culture , blood and blood products , body fluids ,

           human and animals tissue or organs removed at biopsy , surgeryor or autopsy , placenta and

            other products of conception , swabs and other soiled items .

      4.  Non – Infectious hazardous waste :- It Includes chemicals, Radioactive and Pharmacological .

Ø  The amount of waste generated in hospitals under Indian conditions has been estimaled as

1-2 kg per bed . on an average about 85% is harmless and only 15% is hazardous.

v  Method of disposal of waste :- Several Methods of waste treatments are available and the choice of method is based on the item of waste and facilities available. The place of final disposal may be in the premises or away from crowded areas if possible. Some of the methods are :

ü  Chemical Disinfections : - Useful method for many items , particularly in clinics .

Eg : - Sputum or pus are to be disinfected before being buried or autoclaved .

ü  Deep burial : - Materials after chemical disinfection are put in drop trenches covered with time and filled with soil .

ü  Incineration : - Incineration is a process by which waste material is burnt into less bulky osh like material with the help of very high temperature which would be only about a tenth of the origin[al volume . The heat produced by bunners is at a temperature of 2000˚c - 3000˚c. It is very effective and expensive and is generally used only by very establishments .

ü  Autoclaving : - widely used in laboratories and clinics for treating . infectious waste before disposal .

ü  Microwave : - used for sterilization of small volume waste . It cannot be used for animal and human body parts , metals item or toxic or radioactive material .

ü  Liquid Waste : - Pathological , chemical or toxic liquid waste should be properly treated with disinfectant or reagents and heurilization before flushing into the sewer.

Classify Viruses , Discribe Morphology Antigenic property , Transnoission and lab diagnosis of polio virus.

 

Classify Viruses , Discribe Morphology Antigenic property , Transnoission and lab diagnosis of polio virus.

Classification of virus :- on the basis of type of nucleic acids , viruses are classified into two group:-

v  Ribo virus or RNA virus→contains RNA.

v  DeoxyRibo virus or DNA virus →contains DNA.

ü  RNA virus

                 A) Picorana virus (20-30)

Eg→ a) Entero virus

       b) Rhino virus

       c) Rhro virus

       d) Hepato virus (HAV)

               B) Orthomyxo virus ( 80-120nm )

                   Eg:- a) Influenza virus

                C) Paramyxo virus (100-130nm)

                    Eg:- mumps, rubella viruses.

                 D) Arbo virus

                     Eg:- chickengunya , Denque , sendfly fever

                  E) Rhabdo virus (75-180nm)

                     Eg:- Lyssa virus (Rabies virus)

                  F) Reo virus

                  G) Corana virus

                  H) Hepatities – A virus

v  DNA virus

 a) pox virus → Infect vertibrates , birds and insects.

   Eg:- Small pox , cow pox , monkey pox.

                          b) Herpes virus (100- 200)

Eg:- Herpes simplex ( Infect only man) Varicella / chicken pox ( by varicella zoster )                                CVM .        

                          c) Adeno virus

                           d) Papovo virus

                           e) Parvo virus

                           f) Hepatitis – B virus

v  Polio virus

Morphology :- Spherical particle , 30 nm in size , icosahedral symmetry . It can be crystallised which can be seen in infected cell. It is RNA virus belong to family picrona virus.

Antigen:- Three distinct types:

   Type 1 or Brunhillda , Type 2 or Lansing , Type 3 or Leon. Type 1 is most virulent and couse most epidemics , Type 2 causes endemic infection & Type 3 causes epidemic occasionally.

        Transmission :- The virus enter in the body by ingestion or inhalation of contaminated food or drink . They muttifly in Lymphatic tissue of alimentary canal, from the tonsil to the peyer`s patches and enters the regional lymphatics . Then these viruses reaches blood , then spinal cord and then to CNS . In CNS they multiply in neurons and destroy them.

                                                                              The earliest change is the degeneration of Nissle bodies (chromatolysis) Necrotic cell lysis .  lesions are mostly in the anterior horn of spinal cord, causing flaccid paralysis but posterior horns and intermediate column may also be involved . In same cases it causes Encephalitis.

            Lab diagnosis :-

              1) Isolation of virus from threat swab in early stage , virus is grown in Robertson cooked meat media.

               2) Cultivation of virus in tissue culture , cytopathic effect is seen in 3 days . Virus is Identify by Neutralization test.

                3) Cultivation of virus from stool in late stage of disease on Robertson cooked meat media.

                4) Serological  diagnosis by Neutralization or complement fixation test.

What disease produces by streptococci & Describe the diagnosis of Rheurnatic fever.

Diffrent types of disease of produced by streptococci

There are two types of disease of produced by streptococci.

        (a).superficial Lesions

        (i) Cellulitis: Inflamation of interecellular substance causing appearance of fluid in subcutaneous

                                Tissue.

        (ii) Erysipelals: It is appearance of erythematosus plague in epidermis.

        (iii) Lymphangitis: Information of lymph vessels.

        (iv) wound Infection

        (b).Deep Lesions

        (i) Folicular tonsillitis

        (ii) Sore throat: Redness and oedema of mucosa of fleeting nature.

        (iii) Rheumation: Causing acute inflammation of fleeting nature.

        (iv) Acute Glomenulonephritis

        (v) Bronchopneumonia

        (vi) Puerperal Sepsis: Inflamation of uterus and cervix after delivery.

        (vii) Endocarditis

        (viii) Meningitis

        (ix) Septocemia

        (x) Scarlet fever

        (xi) Primary atypical pneumonl

What is universal fixation

A tissue fixative that protects macromolecules (DNA,RNA and protein) and histomorphology in clinical samples is called universal fixative.

Eg:- Formaline, Glutaraldehyde.

Advantage and Disadvantage

 It is a process of maintaining the tissue in the same conditions as removed from the body by preventing autolysis by keeping the tissue in a fixation solution.

 Purpose of fixation:

Ø  To prevent autolysis and to preserve the cell.

Ø  To harden the tissue.

Ø  To conserve the consistency of cells.

Ø  To after refractive index of cells which enable and unstained components to be better visualized.

Fixation is done in two stages:

Ø  Primary fixation

Ø  Secondary fixation

Primary fixation is done in O.T where who organ or tissue is submerged in the fixative.

Secondary fixation is done in Laboratory Large specimen are cut into slices of 1-2 cm thickness and fixed in adequate fixative for 24 hours. Next day it is cut into square. It is further fixed for 5-6 hour before tissue processing embedding is done.

 Chemical composition and mode of action of different fixative: Adv/Disadv.

Formaline:- It is a solution of formal dehyde gas in water

              Commercial formaline-10ml

               N/s-90ml

Advantages:- Normal colour of tissue is retained. It is best fixative for neurological tissue. It is easily prepared and compatible with most stains. It penetrates the tissue rapidly.

Disadvantages:- It causes excessive hardening of tissue.

Ø  Unpleasant vapour causes irritation in eyes.

Ø  May cause allergic reaction to skin.

Ø  Its acidic character may interfare with substain.

Ø  Leads to formation of formaline pigment in tissue having excessive blood at acidic PH.

Zenker’s fluid:- 

      Composition:- Mercuric chloride:50gm

                                 Patasium chloride:25gm

                                 Sodium sulphate:10gm

                                 D/W: upto 1000ml.

Mode of action:- 5 ml GAA is added to 95 ml of Zenker’s fluid just before use. This fixation is used when tissue is to be stained by Masson’s Trichrome stain for connective tissue.

                  Before staining tissue is washed for several hours in running water to remove mercuric chloride pigmentation.

Ø  Mordanting is required to prevent fine grannules of mercury.

Advantages:- Used for 2° fixation, brilliant staining of Nuclei of bone marrow, liver, spleen. It causes excellent staining of connective tissue.

Disadvantags:- Overnight washing of fixative tissue is required to remove yellow colouration caused by dichromate.

           Penetrating power is poor, longer time is required.

Bovin’s fluid:- It is compound fixtive. It has following composition.

Ø  1.22% picric Acid- 750ml

Ø  40% formalin – 250ml

Ø  GAA – 50m

Advantages:- →Best preservative for glycogen.

                         →Brilliant staining by trichrome stain.

                         →Used for hematological and lymphoid tissue.

Disadvantages:- →Picric acid is explosive.

                              →Yellow colour appearance due to picric Acid. Which makes the tissue hard and brittle.

                              →It causes lysis of red cell.

Carnoy’s fluid:-

                         Composition:- ① Absolute alcohol- 300ml

                                                   ② Chloroform- 150ml

                                                   ③ GAA-10ml

Advantages:-

Ø  Used for cyhology of small piece of tissue.

Ø  It has very good penetrating power.

Ø  Dehydration is achieved during fixation.

Ø  It has good for blood film and enzymes demonstration.

Disadvantage:- Chloroform and alcohol are inflammable an Evaporate.

Primary fixatives:- It is initial fixation of whole tissue removed from operation. Usual fixative used is done in formaline. Volume of fixative should be 10-20 times more than the volume of specimen. It should be kept in this solution for 6-24 hrs, minute specimen are wrapped in lens paper or special fine mesh capsule before immersing it in fixative other fixatives that are used are Hgcl2, K2CT2O7, picric acid, Ethylene oxide, Glutoralhyde, osmium tetraoxide and alcohol.

Secondary fixative:- It is also known as refixing, the tissue removed from are cut into pieces of 3-5 mm thick 2-4cm length. Example are formaline, carnoy’s, bovin’s zenker’s fluid etc.

Effecting liver viruses & Hepatitis‘B’virus infection

                          Effecting liver viruses & Hepatitis‘B’virus infection

        Ans :  The following viruses affect liver.

                                 I.            Yellow fever virus ( Arbo virus ).

                               II.            Lyssa fever virus.

                             III.            Merbury virus.

                            IV.            EB virus ( Epstin bar virus ).

                              V.            CXytomegalo virus.

                            VI.            Herpes virus.

                           VII.            Rubella virus.

                         VIII.            Coxsackie virus.

                             IX.            Hepatitis-A virus.

                               X.            Hepatatis-B virus

                             XI.            Hepatitis-C,D &E virus.

 

Ø  Laboratory diagnosis of Hepatitis ‘B’ virus:

                                  I.             Demostration of virus by using immune electron microscope from fecal specimen.

                                 II.            CIE ( Counter in immune electrophoresis ).

                               III.            RIA & ELISA technique are done:-

                              IV.            The following serological and viral marker are done.

a.       Detection of HBSAg – Appears early in blod vafter 6 weeks.

b.       Demonstration of Anti –HBS – Appears after 3 months against HBSAg in serum.

c.       Detection of HBEAg – Derived core protein.

d.       Anti HBe – Appears after disappearencer of HBeAg.

e.       Anti HBc – Detection in serum of Acute hepatitis-B.

f.        HBV DNA – Detected by southeron blot technique present in acute stage.

                                V.            Isolation of virus on tissue culture.

Describe of diphtheria.

 

                                  Describe lab diagnosis of diphtheria.

Causative organism of diphtheria is coryn bacterium It is gram positive, non-motile, rod shaped, non-acid fast bacilli, non-sporing and pleomorphic. Average size Is 3 µ /0.3 µ.

1. Examination of throat swab or laryngcal swab for albert staining.

Ø  Prepare smear from throat swab or laryngeal swab.

Ø  Dry air and fix over flame.

Ø  Pour albert-I for 5-7 mints.

Ø  Blot anmd dry with the help of filter paper.

Ø  Add Albert-II stain keep it for 3-5 mints.

Ø  Wash under tap water.

Ø  Diptheria bacilli shows met achromatic dot two pole of bacillius.

2. Culture from throat swab or laryngeal swab on. Loefflers serom agar and Tellurite blood agar.

Ø  Loefflers serum agar shows gram positive bacilli with metachromatic granule in 6-8 hours.

Ø  Tellurite blood agar shows three diphtheria bacillius (Gravis, Intermedius, mitis)

Ø  Gravis shows Daisy head colonies.

Ø  Intermedius shows frog egg colonies.

Ø  Mitis shows poached egg colony.

3. Virulence test by animal inoculation. Either subcutaneously or intradermal.

Ø  Both emulsion of the culture on loefflers shope is emulsified in 2-5 ml both and 0.8ml of emulsion injected sub-cutaneously in two guinea pig. 1^st Guniea pig gives 500units of antitoxin of C. diphtheria present, 2^nd Guniea pig will die in 54 days.

4. Eleks gel preparation test.

5. Culture on HELA Cell line:- Bacteria is identified by death of cells on cell line.

6. Schick test :- Skin test 0.2 ml of diphtheria toxin injected intradermaly on left for arm and similar does of toxin inactivated by heating at 70 ˚c of 30 mints injection.