Microbiology Unit 5- Lectures 3&4

gram positive

mouth normal flora

stomach and small intestine

few normal flora

has stomach acid, mucus, IgA, bile

large intestine

lots of normal flora

diarrhea

frequent watery, loose stool

dysentery

diarrhea plus mucus, blood, and/or inflammation

gastroenteritis

inflammation of stomach and intestinal mucosa

enterocolitis

inflammation of small and large intestine

stool normal flora

coliforms- lactose fermenter- e.coli

gram + cocci: enterococcus

food intoxication

symptoms caused by toxin

quick onset

food infection

symptoms caused by organism

24-48 hour onset

cavities

caused by viridans streptococci (streptococcus mutnans, streptococcus sobrinus)

ginigivits

caused by anaerobes

periodontitis

chronic issues with ginigivitis

acute necrotizing ulcerative gingivitis

caused by anaerobes

requires debridement

food intoxications

caused by 6 bacteria:

• staph aureus

• clostridious difficile

• bacillus cerues

• clostridium perfringens

• vibrio cholerae

• shingella dysenertiae

staph aureus

some produce enterotoxins (superantigen)

onset: 3-6 hours

transmission: bacteria on food handler (hands, nasal, skin to food)

clostridium difficile

antibiotic-associated diarrhea (infection following broad spectrum antibiotics)

complications: causes pseudomembranous collitis

epidemiology: nosocomial

dx: ELISA for toxins

treatment: fecal transplant

bacillus cereus

caused by 2 toxins:

• diarrheal toxin: found on meats and vegetables

• nausea and vomiting toxin: on rice

clostridium perfringens

on meat, canned goods

toxin is made during sporulation process

vibrio cholerae

aka cholera

produces cholera toxin (makes cells secrete water)

culture/dx: rice water stools

transmission: crustaceans, seafood

treatment: antibiotics, replace fluids

shigella dysenteriae

caused by shiga toxin

symptoms: severe, bloody diarrhea

epidemiology: uncommon in US

shigellosis

caused by shigella sp

shigellosis

culture/dx: non-lactose fermenting on HE and Mac, no black centers on colonies

epidemiology: very contagious

• infectious dose: 10 cells

salmonellosis

caused by salmonella enterica

salmonellosis

gram negative rod

transmission: eggs, meat, milk

culture/dx: non-lactose fermenting on HE and Mac, serotyping

typhoid fever

caused by salmonella typhi

typhoid fever

transmission: fecal-oral, bacteria shed for a year+ after infection

culture/dx: non-lactose fermenting on HE and MAc, colonies with black centers

epidemiology: carriers can spread

symptoms: week 2 » high fever, rash, severe symptoms due to septicemia

EPEC

caused by lactose fermenting e. coli

Mac: magenta

HE: gold/organge color

causes infantile diarrhea

EIEC

acute, severe disease

EHEC

caused by e. coli strain 0157:H7, has acquired shiga toxin

EHEC

culture/dx: lactose fermenter (looks like normal flora)

Mac sorbital plate non-lactose fermenter (pale pink)

ETEC

has acquired a toxin akin to cholera toxin

campylobacteriosis

caused by campylobacter jujuni

campylobacteriosis

most common cause of bacterial gastroenteritis

culture/dx: any growth on campy plate

epidemiology: can lead to guillan-barre syndrome

yersiniosis

caused by yersinia enterocolitica

yersiniosis

refrigerator food poisoning

grows at 4 degrees celcius

gastric ulcers

caused by helicobacter pylori

urease: breaks down urea and raises pH

listeriosis

caused by listeria monocytogenes

listeriosis

transmission: lunchmeat, unpasteurized dairy products

epidemiology: risk of fetal meningitis

mumps

caused by mumps virus

mumps

dx: swelling of cheek and jaw

prevention: MMR vaccine

can cause sterility in males

rotovirus

causes viral gastroenteritis

epidemiology: common in children

norovirus

leading cause of adult viral gastroenteritis

transmission: very contagious, lives on surfaces for 2 weeks

hepatitis A

acute

transmission: ingestion

prevention: vaccine

virulence: can spread to liver

hepatitis B

blood

transmisison: blood, semen, vaginal secretions

epidemiology: asymptomatic in most » chronic carriers

treatment: post-exposure prophylaxis

prevention: vaccine

hepatitis C

chronic

treatment: antiviral, can cure infection

epidemiology: if untreated » chronic hepatitis (liver cerrhosis or cancer)

hepatitis D

dud

epidemiology: higher mortality rate than HBV alone