#microbiology – UNITBALL

TABLE OF CONTENT GIARDIA LAMBLIAMORPHOLOGY TROPHOZOITECYST FORMLIFE CYCLE LAB DIAGNOSIS 1. MICROSCOPIC EXAMINATION 2. ANTIGEN 3. ANTIBODY DETECTION TREATMENT PREVENTION TRICHOMONAS MORPHOLOGY MODE OF TRANSMISSION LIFE CYCLE PATHOGENESIS AND CLINICAL FEATURES LAB DIAGNOSIS CULTURE OTHER SUPPORTIVE TEST TreatmentPrevention : GIARDIA LAMBLIA Giardia lamblia causes giardiasis associated with diarrheal manifestations. It bears flagella as the organ of locomotion. G. lamblia lives in duodenum and upper jejunum and is only protozoan parasite found in the lumen of human small intestine. MORPHOLOGY It exists in two forms : Trophozoite formCyst form TROPHOZOITE Presence of trophozoites indicate active stage of the disease. Measure : 10-20µm in length and 5-15µm in width. Shape: In front view, it is pear shaped or tear drop or tennis racket shaped. In lateral view ,its appears as a spoon or sickle shaped Motility: it has a falling leaf like motility Symmetry ; •One pair of nuclei •Adhesive or sucking disk •Four pair of flagella •Pair of axonemes CYST FORM The cyst is oval in shape and it is 12 µm long and 7 µm broad. There are four nuclei. The axoneme lie diagonally, forming a dividing line within the cyst . LIFE CYCLE Host: giardia completes its life cycle in one host. Infective form : cyst Pathogenic form : trophozoite LIFE CYCLE OF GIARDIA LAMBLIA LAB DIAGNOSIS Microscopic examinationAntigen detectionAntibody detection 1. MICROSCOPIC EXAMINATION Demonstration of giardia cysts in the formed stools and the trophozoites of the parasite in diarrhoeal stools by wet preparation (normal saline and iodine) is useful for diagnosis. ENTEROTEST It uses a gelatin capsule attached to a thread containing a weight. The patient is asked to swallow a gelatin capsule which contains a nylon thread at one end. The free end of the nylon thread is attached to the cheek of the patient. The capsule passes through stomach to the duodenum. In the stomach, the capsule is dissolved and thread remains in the duodenum and jejunum. After two hours, the thread is withdrawn and places in a tube containing saline and mechanically shaken. The centrifuged deposit of the saline is examined microscopically for motile trophozoites of G. lamblia. 2. ANTIGEN Fluorescent method using monoclonal antibodies and ELISA test have been developed for detection of giardia antigen in feces. The triage micro parasite panel is an enzyme immunoassay kit that can detect E. histolytica , E. dispar, Giardia lamblia and cryptosporidium parvum in the stool specimen. It is a rapid test as results are available within 15 minutes. 3. ANTIBODY DETECTION Anti-giardia antibodies may be detected in the patient serum. ELISA and indirect fluorescent antibody test have been used. However, it cannot differentiate present or past infection and hence is not useful in diagnosis. TREATMENT Tinidazole is considered as the drug of choice . Metronidazole or nitrazoxanide is gurazolidone is given alternatively. Furazolidone is given to children and auranofin, paromomycin can be given in pregnancy. PREVENTION Improved food and personal hygiene . Boiling or filtering of potentially contaminated water. Treatment of asymptomatic carriers. No vaccine is currently available. TRICHOMONAS TREATMENT PREVENTION TRICHOMONAS MORPHOLOGY MODE OF TRANSMISSION LIFE CYCLE PATHOGENESIS AND CLINICAL FEATURES LAB DIAGNOSIS CULTURE OTHER SUPPORTIVE TEST TreatmentPrevention : Trichomonas differs from other flagellates , as they exist only in trophozoite stage . Cystic stage is not seen . Genus trichomonas has divided into three species : Trichomonas vaginalis ( T. vaginalis )Trichomonas hominis ( T. hominis)Trichomonas tenax ( T. tenax ) MORPHOLOGY It is pear shaped about 10-30µm in length and 5-20µm in breadth with short undulating membrane reaching upto the middle of the body. It has four anterior flagella and one lateral flagellum called as recurrent flagellum which traverses the parasite as an undulating membrane than in turn supported at the base by rod like structure named “costa”. The single ovoid nucleus is present at the anterior end and the posterior end is pointed. The axostyle runs down the middle of the body and end in the pointed tale like extremity. It is motile with a jerky movement. It divides by binary fission. The trophozoite is the infective form as there is no cystic form. MODE OF TRANSMISSION The trophozoite cannot survive outside and so infection has to be transmitted directly from person to person . Sexual transmission is the usual mode of infection. Trichomoniasis often coexist with the other sexually transmitted diseases like candidiasis, gonorrhea, syphilis or HIV. Babies may get infected during birth. Vaginal pH of more than 4.5 facilitate infection. LIFE CYCLE Trophozoite has two forms: 1.Flagellated trophozoite : it is the infective form as well as the diagnostic form. 2.Amoeboid trophozoite : it is an actively replicating form, found in the tissue feeding stages of the life cycle. Asymptomatic females are the reservoir of infection. Human acquire infection by sexual route flagellated trophozoite after entry , transform into amoeboid forms. These forms which multiply in the genital tract cause infection. They again transform back to flagellated trophozoite that are discharge in vaginal secretions. PATHOGENESIS AND CLINICAL FEATURES T. vaginalis particularly infects squamous epithelium . It secrets adhesins proteins which helps in attachment to the vaginal epithelium . In females, it may produce vulvovaginitis characterized with an offensive yellowish discharge. Colpitis macularis : strawberry appearance of vaginal mucosa is observed in 2% of patients . The infection is often asymptomatic especially in males, although some may develop urethritis , epididymitis and prostatitis. LAB DIAGNOSIS Microscopic examination a)Wet mount preparation: Vaginal or urethral discharge is examined microscopically in a drop of saline for characteristic motile trophozoite with jerky movement. It is named “wet mount” preparation.Specimen should be examined within 10-20minutes of collection. STAINING METHODS •Fixed smears stain with Giemsa stain and observed under light microscope. •Direct fluorescent antibody (DFA) test is another method for detection of parasite. It is more sensitive than wet mount preparation. •Acridine orange fluorescent stain can be used it is rapid and sensitive comparable to wet mount. CULTURE Culture is considered as a gold standard method for diagnosis of t. vaginalis infection. The parasite can be isolated from urethral and vaginal discharge on a variety of media. CPLM (cysteine, peptone, liver, maltose) medium is often used. “In pouch TV” is selective culture device for inoculation of specimen at point of care Antigen detection ELISA is used for demonstration of Trichomonas antigen. Rapid immunochromatographic (ICT) is also available for detection of antigen. Molecular methods Nucleic acid hybridization method and polymerase chain reaction for the diagnosis of trichomoniasis. OTHER SUPPORTIVE TEST Positive whiff test: fishy odor is accentuated when a drop of 10% KOH is added to production of amine. It is positive in more than 75% of cases. It is also positive in bacterial vaginosis Treatment Metronidazole or tinidazole is the drug of choice. Prevention : 1.Treatment of both the partners. 2.Safe sex practices like use of condoms . 3.Avoidance of sex with infected person . 4.There is no effective vaccine licensed so far. THANK YOU HAVE A NICE DAY & DROP A COMMENT BELOW YOU CAN REQUEST A TOPIC ON MAIL AND AS WELL AS IN A COMMENT BOX STAY TUNED FOR MORE TOPICS LIKE THIS AND DON'T FORGET TO SHARE THIS [jetpack_subscription_form show_subscribers_total="false" button_on_newline="false" custom_font_size="16px" custom_border_radius="0" custom_border_weight="1" custom_padding="15" custom_spacing="10" submit_button_classes="" email_field_classes="" show_only_email_and_button="true" success_message="Success! An email was just sent to confirm your subscription. Please find the email now and click 'Confirm Follow' to start subscribing."]

Tag: #microbiology

GIARDIA LAMBLIA & TRICHOMONAS

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