BACTEC TB-460 : rapid,specific,&rapidculture method Both respiratory & non respiratory specimens 13-14 days 200 viable bacilli 14-17 days 20 viable bacilli
Mycobacterial growth indicator tube(MGIT)960 Art fluorescent technology Rapidly 7-10 daysBased on O2 quenching of mycobacteria withfluorescent dye
Uses specific Mycobacterial phages to detectviable bacteria within 48 hrs
Serology helps in detecting either thespecific or non specific immune responsesof the host or the presence of the antigen inthe host
Specific Ig G &Ig M can be detected usingimmunologic techniques against virusesVarious types includeprecipitationAgglutination widal testComplement fixationimmunofluorescenceElisaWestern blot
Specific,sensitive,simple,inexpensible,& reproducibleUsed extensively to detect either Ag or AbAlso detects small quantities of AgUsed to diagnose TORCH,HIV,MEASLES,HEPATITIS(A,B,C,D,E)…….
Tag Ab with fluorescein isothiocynateAb-virus complex or viralantigensmicroscopically by UV illuminationDetects viruses which are uncultivable
Ω Assays are available for rapid detection ofbacterial Ags in various body fluidsΩ Useful when prior antibiotic therapy hasbeen initiated and cultures are negative after24 hrs of incubation
Detection of microbialantigens/products The following fluid/samples can be assayed CSF: Latex agglutination & counter-currentimmuno electrophoresis are used todemonstrate the soluble polysaccharide Agof cryptococcus &….
Detection of microbialantigens/products Serum- Pl.falciparum/vivax are detected atlevels of 100-200 parasite/űl Urine-strep.pneumonia legionella, Stool :helicobacter pylori,clostridiumdifficile,giardia
Detection of microbialantigens/products GLC : anaerobes HPLC : mycobacteria
New developments Answer for organisms with growthcharacteristicsslow – mycobacteriadifficult – viruses,chlamydiafastidious- mycoplasma
Highly sensitive – detects low pathogen no’sas in meningitisUsed to monitor response to treatment(viral load assays for hepatitis B,C&HIV)
Nucleic acid probes :NA hybridization is powerful & widely usedtechniqueUsed to detect and locate specificDNA&RNA sequence in tissues orchromosomes by making use ofradioactive/fluorescent labelled DNA/RNAprobes complementary to the requiredsequence
Commercially available for the available foridentification of M.tuberculosiscomplex,avium,intracellulaire,kansasi,gordonae
Nucleic acid amplication- Target amplificationPCR : An in vitro method for amplifyingspecific DNA sequenceextremely minute amounts of NAgenerates billions of exact copiesmaking genetic analysis a simpleprocess
Target DNA acts as templatenucleotidesprimers&DNA polymerasegenerates copies by alternate heating &cooling for denturation, annealing, &extension
Nucleic acid amplication- Target amplificationReal time PCR : rapida fluorescent signal is used forreal time monitoring of amplificationTranscription mediated amplification Uses ribosomal rna as the target for reversetranscriptase
Nucleic acid amplication-signalamplification Increases the signal generated fromhybridized probe moleculeProbe amplificationEnd product is an amplified version of originalproduct includes LCR, cycling probetechnologyIn LCR phenotypic change in the organism suchas virulence or drug resistance
Disadvantages of molecularmethodsAmplification can amplify even minutequantities of contaminating DNA – false (+)Do not differentiate dead from livingorganismsFalse(-) results may due to low copy no’s ofmicroorganisims at site of infection
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.