4/18/20131 Means identification of theorganisms to strain level. The main purpose to controlnosocomial infection and also canused in different epidemiologicalpurpose (cholera, meningitis …etc).
4/18/20132Similarity between isolatesWide range of characters that could be examinedSignificance of differences needs to be understoodSignificance of differences needs to be clearly expressedRelationship to other strainsComparator strains mustBe recognisable by the typing methodsHave known characteristics Phage typing. Bactericin typing. Resistotyping. Biotyping. Serotyping. Plasmid typing
4/18/20133 Phage is virus which live in a livingcell. Bacteriophage: is a virus live in abacterial cell, and used for typing ofbacterial, it is specific and live incertain strain. There are two type of bacteriophage: Lytic bacteriophage: cause lysis ofbacterial cell and used for typing. Lysogenic bacteriophage: Does notcause lysis of bacterial cell but playimportant role in the gene transferring. There is a bacteriophage for anybacteria but usually used for typingof S. aurus in control of nosocomialinfections. Phage typing also used for differentepidemiological purpose as inMycobacterium, Brucella,Salmonella…etc.
4/18/20134 Phage typing of S. aureus: There are 4main group I, II, III and IV. And eachgroup consist of different number ofsingle phage. Method: Reconstitute the phage (activation the virus). Inoculate the NA plate with the testedorganism after labelling. Add the phage as drop, incubate and readresult Advantage: Very specific method. Disadvantage: Difficult to perform –need well equipped laboratory(preservation of virus) – timeconsuming – not used for all type oforganisms.
4/18/20135 Bactericin is antibiotic-like substanceproduced by certain organism thatcan inhibit the growth of some closerelated bacteria. Eg: Colicin typing used for typing ofShigella sonni Depend on biochemical reaction. Modified from identification totyping. Most used Analytical profile index(API). Eg: API 20 E
4/18/20136 Advantage: Easy to perform –Standardized. Disadvantage: Cannot used forall organisms.
4/18/20137 Depend on serological reactions. Used for identification and can beused for typing. Advantage: standardized – specific –easy to perform. Disadvantage: Cannot used for allmicroorganisms. Also called antibiogram. It is sensitivity test for typing. Used different type of antimicrobialagents differ from that used fortreatment (toxic may be dyes). Advantage: easy to perform-simple-cheap. Disadvantage: limited sensitivity(for organism highly sensitive orresistant).
4/18/20138 Also called molecular typing, eg;PCR. Advantage: very sensitive-veryspecific. Disadvantage: need special machine-very expensive method.