• 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