microfinal

• routinely done to monitor the prevalence of antibiotic resistant bacteria
• Observe for a trend in order to take precautionary measures

• development of new drugs
• determining the molecular basis for resistance and modify existing drugs accordingly

• test the antibiotic sensitivity of an organism
• takes away the guessing when choosing antibiotic
• lets you know if it's gram positive or gram neg.

• Prepare a pure culture (18-24 hrs) of the sample on a non-selective medium
• Adjust turbidity until it is equivalent to the 0.5 McFarland Turbidity Standard
• Within 15 minutes of adjusting the turbidity dip a sterile cotton swab into the sample
• streak a lawn of bacteria on Mueller-Hinton agar
• Leave the lid agar for 3-5 minutes (no more than 15 minutes) to allow plate to dry
• Apply antibiotic impregnated disks on the bacterial lawn
• Important: where the disk drops is where it stays
• Incubate for 16-18 hours at 33 ± 2C unless otherwise instructed

• Antibiotics diffuse out onto the agar
• Concentration of antibiotics decrease as they diffuse further away from the disks
• After incubation, observe for a clearing on the  bacterial lawn (zone of inhibition)

• Measure the diameters of the zone of inhibition
• Interpret the results as “resistant” or “susceptible”  according to the guideline provided by the NCCLS
• Interpretation of the zone of inhibition is different for  each bacteria-antibiotic combination

• zone of inhibition (yellow)
• bacterial growth (orange)

trichomonas vaginalis 

trichomonas vaginalis

• plasmodium falciparum ring stage
• (malaria)

leishmania donovani

trypanosoma cruzi in blood smear

toxoplasma gondii

entamoeba histolytica intestinal lesions

balantidium coli

Trypanosoma gambiense

Naegleria fowleri

• Pathogen: entamoeba histolytica
• Symptoms: abscesses; significant mortality rate
• Reservoir: humans
• Diagnosis: microscopy; serology
• Treatment: metronidazole

• Causative agent: trichomonas vaginalis
• Found in: semen or urine of male carriers
• SS: Vaginal infection that causes irritation and profuse foul, greenish yellow frothy discharge
• pH:5-8
• Diagnosis: microscopic ID; DNA probe
• treatment: metronidazole

• ID in the blood, CSF
• SS (sleeping sickness), fever, sleepiness, unconsciousness
• Motility due to flagella

• Causative agent: trypanosoma cruzi
• Reservoir: rodents, opossums, armadillos
• Vector: reduviid bug

• Causative agent: giardia lamblia
• SS: most asymptomatic, chronic diarrhea, dehydration, abdominal pain
• ID: by cyst form or trophozoites in stool
• Transmission: contaminated food or water
• Motility: flagella

• Disease: visceral Leishmaniasis
• Causative agent: leishmania donovani
• vector: sandflies
• reservoir: small mammals
• treatment: amphotericin B or miltefosine
• geographic distribution: south asia, sudan, brazil

• Causative agent: balantidium coli
• SS: mostly asymptomatic, diarrhea alternating w/ constipation, blood and mucus in feces
• ID: cyst form or trophozoites
• Motility: cilia

• Causative agent: Plasmodium falciparum
• SS: chills, nausea, vomiting
• vector: anopheles mosquito
• definitive host: anopheles mosquito
• control: bed nets
• treatment: artemisin

• 1. Infected moquito bites human; sporozoites migrate through bloodstream to liver of human
• 2. Sporozoites undergo schizogony in liver cell; merozoites are produced
• 3. Merozoites released nto bloodstream from liver may infect new RBCs
• 4. Merozoite develops into ring stage in RBC
• 5. Ring stage grows and divides, producing merozoites
• 6. Merozoites are released when RBC ruptures; some merozoites infect new RBC and some develop into male and female gametocytes
• 7. Another mosquito bites infected human and ingests gametocytes
• 8. In mosquito's digestive tract, gametocytes unite to form zygote
• 9. Resulting sporozoites migrate to salivary gands of mosquito

• Pathogen: crytposporidium hominis
• SS: self-limiting diarrhea; may be life threatening in immunosuppressed ppl
• Reservoir: cattle; water
• Diagnosis: acid-fast stain; FA; ELISA
• Treatment: oral rehydration

Ascaris lumbricoides eggs

clonorchis sinensis eggs

Enterobius vermicularis eggs

Enterobius vermicularis eggs (too)

Necator americanus adult

schistosoma japonicum eggs

schistosoma mansoni miracidiae

tapeworm, scolex

tapeworm, proglottis

• 1. Ascaris (30%)
• 2. hook worms (21%)
• 3. enterobius (10%)
• 4. schistosome (6%)
• 5. tapeworms (3%)
• 6. flukes-liver, lung (1.5%)
• 7. trichinella (1%)

• 1. trematodes (flukes)
• 2. cestodes (tapeworms)
• 3. nematodes (roundworms)

• 1. C. sinensis
• 2. Clonorchiasis (liver disease)
• 3. Japan, Korea, Taiwan, US (Southern Asian Immigrants)
• 4. ingestion of infected undercooked fish
• 5. eggs in feces
• 6. Praziquantel - increases the permeability of the membranes of parasite cells(paralysis); Albendazole - depletes their glycogen stores

• 1. Embryonated eggs passed in feces
• 2. eggs ingested by snail, go from miracidea to sporocysts to rediae to cercariae
• 3. free swimming cercariae encysts in the skin or freshwater fish
• 4. Metacercariae in flesh or skin of freshwater fish are ingested by human host
• 5. excyst in duodenum
• 6. adults in biliary duct

Method of isolation that allows for the formation of individual colony forming units by reducing the number of bacterial cells with each streaked quadrant.

• a laboratory culture containing a single species of organism.
• A pure culture is usually derived from a mixed culture (one containing many species) by transferring a small sample into new, sterile growth medium in such a manner as to disperse the individual cells across the medium surface or by thinning the sample manyfold before inoculating the new medium.

refers to a procedure that is performed under sterile conditions.

• morphology
• arrangement

A Slide that has had bacteria placed on it and that has been treated to cause the bacterial cells to adhere to the slide

Small drop of water scoop small amount of bacteria onto slide and spread in small cirular motionheat fix to adhere the slide

To adhere the bacteria to the slide and to help sterilize the surrounding area of the slide

method where a drop of a culture is placed directly on a coverslip (there is a circular depressed area in the middle of the slide) allowing the drop of broth to hang in the space of the depression. This technique is useful for thick cells such as protozoans must be examined

Used to examine live organisms

when nonmotile organisms exhibit a dancing or jiggling motion that does not result in traveling any distance this is a specific name for this motion

to be able to examine single cells through a microscope.

Used as general, all purpose stains.

Usually basic dye that will stain the cell membranes are negatively charged.

• 1. Cocci
• 2. Bacilli
• 3. Vibrios
• 4. Spirillum/Spirochetes

• 1) Choose isolated colony
• 2) Place bacteria on slide in a circular motion
• 3) Heat fix for about 30 seconds
• 4)Place on staining tray
• 5) Flood surface with crystal violet
• 6) rinse with water
• 7) flood surface with iodine
• 8)Rinse with water
• 9)Flood with Alcohol
• 10) rinse with water
• 11) flood Safranin
• 12) rinse- blot slide read with oil immersion lens of microscope- look for gram - and gram +bacteria

• Prepare smear. Heat fix.
• Add Kinyoun's carolfuchsin and stain for 5 min. Rinse with water.
• Flood slide with acid-alcohol for 3 min. Rinse with water.
• Add acid-alcohol for 1 min or until no more stain is removed from smear. Rinse with water.
• Counterstain with methylene blue for 1 min.
• Rinse slide with water and air-dry.

gram stain

acid fast stain

capsule stain

flagella stain

endospore stain

• 1. adult female lay eggs
• 2. eggs reach body of water after being excreted in feces or urine
• 3. eggs hatch into free-swimming larvae -> miracidium
• 4. miracidium penetrates snail
• 5. miracidium reproduces in snail, forming several cercariae
• 6. cercaria are released from snail
• 7. free swimming cercariae penetrate human skin, losing tail
• 8. cercariae travl through circulatory system to intestinal BVs where they mature into adults.

• 1. adult female lay eggs in feces or urine
• 2. eggs hatch and release miracidia
• 3. miracidium penetrates snail
• 4. miracidium reproduces in snail -> sporocysts ->cercariae
• 5. cercaria are released from snail
• 6. free swimming cercariae penetrate human skin
• 7. cercariae lose tail during penetration, become schistosomulae
• 8. travel through circulatory system
• 9. migrate to portal blood in liver and mature into adults
• 10. paired audlt worms migrate to mesenteric venules of bowel/rectum (laying eggs that circulate to the liver and shed in stools) and to venous plexus of bladder

• 1. Eggs are passed in the stool,  larvae hatch in 1 to 2 days.  The released rhabditiform larvae grow in the feces and/or the soil 
• 2. after 5 to 10 days they become filariform (third-stage) larvae that are infective . 
• 3. On contact with the human host, the larvae penetrate the skin and are carried through the blood vessels to the heart and then to the lungs.  They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed .
• 4. The larvae reach the small intestine, where they reside and mature into adults.  Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host . 
• 5. Most adult worms are eliminated in 1 to 2 years, but the longevity may reach several years.

having both male and female organs in the sameindividual; hermaphroditic.

having the male and female organs in separate and distinct individuals; having separate sexes.

the anterior, headlike segment of a tapeworm, having suckers,hooks, or the like, for attachment.

one of the segments or joints of a tapeworm, containing completereproductive systems, usually both male and female.

• Useful in clinical isolation of enterobacteriaeae
• Media are designed to encourage the rowth of nterics while discourage the growth of harmless bacteria
• Distinguish lactose fermenters such as E. coli from non-lactose fermenters such as Salmonella Shigella

• Gram -
• lactose fermentation

ferment lactose

Eosin methylene blue

differential

Gram +

color

Nucleated colonies

metallic sheen

• Salmonella
• Shigella

Hektoen Enteric Agar

• lactose fermentation
• H₂S

• Black
• Green
• H2S
• Lactose fermentation
• non-lactose fermenters

Triple sugar iron

• Ferment sugars
• H₂S

• lactose
• sucrose
• glucose

TSI agar

tsi

• yellow
• glucose
• sucrose

• C: no fermentation
• 1: neg. for fermentation
• 2. glucose only
• 3. glucose fermentation + H₂S production
• 4. Glucose + lactose fermentation + gas
• 5. Glucose and lactose fermentation plus gas and H₂S

a self-contained sterile plastic tube with 12 compartments containing distinct media that permit different biochemical tests to be done.

• A. peptonization
• B. Alkaline, lactose Not fermented
• C. lower pH, more acidic
• D. lower pH, more acidic
• E. Lactose fermented, most acidic

vorticella

paramecium in conjugation

volvox sexual stages

diatoms