A Great Islamic scolar,Ibn-al Qayyaum R.A said: the things that make the body sick are: Too much! talking, Too much sleeping, Too much Eating

laboratory diagnosis of infectious diseases Bacteriologic Immunologic(serologic) Molecular (nucleic acid–based) tests

Koch, s postulates Organism must be present in lesions in every case of disease Possible to isolate org in pure culture Inoculation of pure culture in lab animal should produce disease Possible to reisolate the org

MICROBIOLOGICAL DIAGNOSIS Multi-step process Clinician- patient meeting Specimens – quality of specimens is crucial Specimen from sterile sites- enrichment media Specmen from a site with a normal flora- selective media to supress the growth of commensal organisms

MICROBIOLOGICAL DIAGNOSIS Specimen choice Apropriate specimens Containers –labelled sterile containers Transport – Specimen quality control –result depend on quality of specimen Identify unsatisfactory specimens

MICROBIOLOGICAL DIAGNOSIS- LAB EXAM Direct exam – Microscopy –rapid presumptive diagnosis Saline wet preparation of stool Gram, s stain, Ziehl-Neelsen stain, Leishman, s stain, Culture –amplification in number of pathogens, Selective media –discrimination between pathogens & non-pathogens

MICROBIOLOGICAL DIAGNOSIS- LAB EXAM Culture on solid media –isolated colonies for identification & susceptibility testing Media for bacterial culture Serology & antigen detection –rapid diagnosis, organisms difficult to culture

HAZARDS IN PATH LABS unsafe premises Naked flames Chemical hazards Glassware hazards Equipment hazards Explosions Microbial hazards

BIOHAZARDS IN PATH LABS Ingestion – Contaminted fingers, mouth pipettting,eating food in lab, Inoculation – Needlestick injuries, injury from broken contaminated glassware, open uncovered skin wound

BIOHAZARDS IN PATH LABS Inhalation – Infected airborne droplets Infection of general public – Escape of microorganisms during transport, improper disposal of infectious waste

Classificaton of infective microorganisms Risk group 1 – Low risk to lab worker & members of community eg. Food spoilage bacteria, yeasts, common moulds

Classificaton of infective microorganisms Risk group 2 – moderate risk to lab worker & limited risk to members of community, Can cause serious human disease Staphylococci, streptococci, enterobacteria, clostridia, vibrio, adenovirus, poliovirus, hepatitis viruses, toxoplasma, leishmania

Classificaton of infective microorganisms Risk group 3 – High risk to lab worker & low risk to members of community, Can cause serious human disease Brucella spp, Mycobacterium tuberculosis, S. typhi,francisella, arboviruses, LCM virus, rickettsiae, chlamydia, coccidioides, histoplasma, HIV

Classificaton of infective microorganisms Risk group 4 – High risk to lab worker & to members of community, Can cause serious human disease & readily transmitted from one person to another Viruses of haemorrhagic fevers, Marburg, Lassa, Ebola

SAFE LAB PRACTICES Safe working environment – Display safety signs & notices Keep lab clean Separate & dispose waste Decontamination procedures Disinfectants & their use in lab Sterilization Regulations for safe packaging & transport of specimens Reporting of faults

SAFE LAB PRACTICES SAFE WORKING PRACTICES- Personal hygiene Protective clothing Preventing lab acquired infections Handling of spillage of a specimen Working tidily, use of racks, Use of protective gloves, goggles, face shield, dust mask,

DUTIES OF LAB SAFETY OFFICER Monitor safety reg in lab Staff taught to handle fire, equipment fault, specimen or chemical spillage Test methods are safe No mouth pipetting Use of protective clothing in lab No smoking, eating, drinking, applying cosmetics

DUTIES OF LAB SAFETY OFFICER maintenance of first aid box, eye wash bottles, fire extinguishers Cleanliness of lab, benches free of books & personal property Maintenance of equipment Observe safety reg regarding pts & visitors to lab are followed Check structural defects in lab Review & discuss safety reg with staff

UNIVERSAL PRECAUTIONS Blood & certain body fluids ( amniotic fluid, CSF, pleural fluid, peritoneal fluid, pericardial fluid, semen, vaginal secretions, any fluid visibly contaminated with blood ) of all patients are potentially infective.

UNIVERSAL PRECAUTIONS Hand washing before & after all patient contact Use of gloves if soiling of hands with blood is likely Gowns should be worn if soiling of skin or clothing is likely Mask Protective eyewear Private room for patient if hygienic practices are poor

UNIVERSAL PRECAUTIONS Proper disposal of contaminated needles/sharps in puncture resistant containers No resheathing/recapping of used needles Spills of blood – cleaned with 1:10 dil of bleach Barrier precautions ( masks, protective eyewear, gowns ) indicated, when splashes are expected to be generated.

LAB INFECTIONS - TYPES OF ACCIDENTS Splashes & sprays Needlesticks, sharp objects, Mouth pipetting Animal bite or scratch

MICROBIOLOGY Five basic techniques in microbiology –five I, s Inoculation, incubation, isolation, inspection, identification