3 Microbilogylecturelab
-
Upload
miami-dade -
Category
Technology
-
view
1 -
download
0
description
Transcript of 3 Microbilogylecturelab
![Page 1: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/1.jpg)
Microbiology
Antonio Rivas PA-C
Feb 2008
![Page 2: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/2.jpg)
Microbiology
• Clinical microbiology encompasses– Bacteriology– Parasitology– Virology– Mycology
![Page 3: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/3.jpg)
Bacteriology
• Characteristics of bacteria– Multiply by fission– Grow in colonies
• Morphology– Coccus– Bacillus– Spiral– Growth patterns
![Page 4: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/4.jpg)
Specimen collection
• Collect before antimicrobials are given• Specimen collected where the organism is
most likely to be found w/o external contamination
• Stage of the disease– Enteric pathogens are present in higher numbers
during the acute or diarrheal phase of the infection
• Sufficient quantity of specimen • Prompt delivery to the lab
![Page 5: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/5.jpg)
Aseptic Technique
![Page 6: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/6.jpg)
Techniques Culture
![Page 7: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/7.jpg)
Culture Techniques
![Page 8: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/8.jpg)
Bacteriological Growth Media
• Agar plates contain different components that enhance or inhibit the growth of certain microorganisms
• Examples:– MAC-selective media - inhibits Gram
Positive organism– HE- selective media- inhibits Gram
negative organism
![Page 9: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/9.jpg)
Bacteriological Growth Media
![Page 10: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/10.jpg)
Incubation - Plates are incubated for :24-48 hrs at different temperature and O2 concentration-
- Most human pathogens grow best at 35-37 degree C
![Page 11: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/11.jpg)
Culture Techniques
• Observing culture after 24 hours– Colony characteristics– Presence (or absence) of hemolysis
Staphylococcus aureus Beta hemolyticus strept.
![Page 12: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/12.jpg)
Colony Characteristics• Colony size, shape, moist or dry, color, smell
• Pseudomonas sp. Smells like grapes• Neisseria gonorrhea smells like sweaty tennis shoe• Shigella is mucoid and purple
– Presence of hemolysis in blood agar plate (Strep.pyogenes-throat inf.-beta hemolysis)
• Beta-hemolysis:• Lysis of the red cell present in the media showing clear
area around the bacterial growth
![Page 13: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/13.jpg)
Automated ID
![Page 14: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/14.jpg)
Gram Stain• Bacterial species divided into two groups
according to how they take Gram Stain– Gram positive : take up the crystal violet basic
stain (stain purple)– Gram negative : allow the crystal violet to easily
washout with acetone and take up the Safranin dye (stain pink)
– Related to the cell membrane composition
![Page 15: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/15.jpg)
Gram Stain
• Important for– Bacterial identification– Antibiotic susceptibility testing– Preparing a smear
• From a swab• From a culture
![Page 16: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/16.jpg)
Preparing the Bacterial Smear
• Heat-fixing the smear– Smear must be dry– Affixes bacteria to slide– Do not use excessive heat
![Page 17: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/17.jpg)
Gram Stain
• Primary stain
• Gram’s iodine– Mordant
• Decolorizer
• Counterstain
![Page 18: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/18.jpg)
Observe the Stained Smear
• Oil immersion
• Gram reactions– Gram (+) → purple– Gram (-) → pink
![Page 19: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/19.jpg)
Microbiology
• Bacteremia : transient release of bacteria to the blood stream, indicates the presence of a focus of disease
• Septicemia or Sepsis : a situation in which bacteria and their products are causing harm to the host
• Terms are used interchangeable
![Page 20: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/20.jpg)
• Portals of entry for septicemia:– GU– Respiratory– Abscesses– Surgical wound infections– Biliary tract– Other sites
• Organisms most commonly isolated from blood are:– Gram positive cocci– Coagulase neg staphylococci– Staphylococcus aureus– Enterococcus sp.
![Page 21: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/21.jpg)
• Meningitis: infection in the subarachnoid space, between the Pia-mater and the Arachnoid
• Dx by PE, CSF analyisis, and cultures • Hematogenous spread• Children <5 years
– Haemophilus influenza
• Neonates– Group B streptococci– E.coli– Listeria sp.
• Most common bacteria causing meningitis in children age 6 years and up– Haemophilus influenza– Neisseria meningitidis – Streptococcus pneumoniae
![Page 22: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/22.jpg)
• Meningitis in adults– Neisseria meningitidis(young adults crowded
conditions)– Pneumococci – Listeria monocytogenes– Staphylococcus aureus
![Page 23: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/23.jpg)
Staphylococcus saprophyticus
• Gram positive cocci• Second cause of UTI in young females after
E.coli• Symptoms :• Burning when urinating• Increased urge to urinate• Dripping effect• Razor like pain in the lower abdomen and
during intercourse• Treated with Quinolones in the US
![Page 24: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/24.jpg)
Enterococcus faecalis
• Gram positive bacilli
• Inhabitant in GI tract humans and animals
• Life threatening nosocomial infections
• High level antibiotic resistance
• Can cause endocarditis, bladder, prostate and epididymal infections
![Page 25: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/25.jpg)
Streptococcus pyogenes
• Gram positive cocci in chains• Group A, beta hemolytic• Strept throat-pharyngitis• Impetigo• Cellulitis• Necrotizing fasciitis• Toxic shock• Rheumatic fever• Glomerulonephritis• Sensitive to penicillin
![Page 26: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/26.jpg)
Candida albicans
• Yeast, fungi
• Opportunistic oral and genital infection in immunocompromised patients
• Live in human mouth and GI
• May occur in blood
• Thrush – immunocompromised
![Page 27: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/27.jpg)
Cryptococcus neoformans
• Encapsulated yeast-like fungus
• Cryptococcal meningitis in immunocompromissed patients
• India ink stain used for Dx in CSF
![Page 28: 3 Microbilogylecturelab](https://reader035.fdocuments.us/reader035/viewer/2022070301/54559309af795989638b8dc1/html5/thumbnails/28.jpg)
E.coli
• Gram negative rod
• Virulent strains can cause gastroenteritis, UTI, neonatal meningitis
• Ascending UTI with fecal contamination