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.