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91 Cards in this Set
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antibiotic associated diarrhea
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Normal flora prevent colonization
Use of antibiotics disrupts the normal flora resulting in mild to severe diarrhea Sometimes causes life threatening disease toxin colonize newly uninhab intestine and damage epil cells |
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streptococcus mutans
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gp
faculatative anaerobe causing dental carries glucans attach and remain on tooth surface produce lactic acids when metabol, sugar |
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dental caries prevention; treatment
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good general hygiene
reduction or elimination of sugary foods, fluridated drinking water drilling of dis. region and filling defect to restore contour of tooth |
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helicobacter pylori
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gn
sheated polar multiflagellated microaerophillic gastritis and peptic ulcers produces urease survung in xtremly toxic environs ceating own alkaline environ |
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gastritis and peptic ulcers
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halitosis abdominal pain vomiting
can pentrate mucus lining of stomach causing inflamm response dec in mucous product causing ulcers antibiotics that inhibit stomach production |
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barry marshall
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proved peptic ulcers caused by h pylori
won nobel prize drank culture |
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vibrio cholerae patho
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heat labile cholera toxin
encoded by filamentous bacterial phage |
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ab toxin
b subunit |
(not toxic) binds to gangliosides on epithelial cell surfaces allowing internalization of the A subunit.
A fragment responsible for toxicity, causes excess secretion of fluid |
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ab toxin a subunit
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catalyses ADP-ribosylation of G protein, which in turn activates adenylate cyclase present in the cell membrane of the epithelium of the gut.
Leads to overproduction of cyclic AMP |
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cholera symptoms
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nonbloody watery diarrhea rice water
vomitting common muscle cramps due to loss of fluid secretion of ct enterotoxin leads to symptoms |
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shigella 4 species
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flexnuri
boydii sonnei dysenterriae |
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shigella
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young children
fecal oral route causes shigellosis |
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shigella patho
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Bacteria taken up by M cells
M cells transport bacteria beneath epithelium Bacteria adhere to specific receptors near base of epithelial cells Move from cell to cell via actin tails Dead cells slough off Initiates intense inflammatory response Causes blood in feces |
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shigellosis
s.dysenteriae patho |
Shiga Toxin
A-B toxin The toxin inhibits protein synthesis Toxin associated with fatal hemolytic uremic syndrome (HUS) Red blood cells break up in the tiny blood vessels of the body resulting in anemia and kidney failure |
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shigellosis epidem
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a human source of transmission
Transmitted fecal-oral route Organism not easily killed by stomach acid Does not have a high infecting dose overcrowding Also common in day cares and among homosexual men Contaminated food and water also responsible for outbreaks |
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shigellosis treatment
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sanitary measures surveillance of food handlers and water supplies
no vaccine available fluid and electrolyte replacement ampicillin and cotrimoxazole shorten duration of symptoms some species resistant to antibio |
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e.coli eneterotoxigenic ETEC
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Most common cause of traveler’s diarrhea
heat-labile toxin (LT) like cholera toxin and heat-stabile toxin (ST) which stimulates guanylate cyclase. |
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e.coli (EIEC) enteroinvasive
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Disease closely resembles that of Shigella species
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e.coli enteropathogenic (EPEC)
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Causes outbreaks in hospital nurseries and bottle fed infants in developing countries
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e.coli enterohemorrhagic (EHEC)
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Often produces severe illness due to production of potent group of toxins but no inflammation
Toxins closely related to Shiga toxins Many infected individuals develop HUS Most common strain O157:H7 |
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e.coli symptoms
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vomiting and a few loose stools to profuse water diarrhea to severe cramps and bloody diarrhea
Fever not usually prominent Recovery usually occurs within 10 days depends on virulence of strains |
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e.coli patho
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Possesses four important virulence factors
Capsule LPS Pilli Enterotoxins |
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salmonellosis
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motile
gn enteritidis, cholerae suis, and thphi lives in i tracts of animals infects humans though water and food contamm with animal feces |
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salmonellosis symptoms
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usually presents as a gastroenteritis (nausea, vomiting and non-bloody stools)
Symptoms vary depending on virulence of strain and number of infecting organisms Symptoms are generally short-lived and mild |
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salmonellosis patho
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Organisms cross membrane and resist killing by macrophages
Bacteria multiply within macrophages then carried to bloodstream Organisms are released when macrophages die and invade tissues Can result in abscess, septicemia, and shock food handler cause alot of spread Bacteria sensitive to stomach acid Large number required for infection |
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salmonellosis epidemio
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Bacteria can survive long periods in the environment
Children are commonly infected Generally by household pets such as turtles, iguanas, and baby chicks Most cases have an animal source Enteric fevers, such as those caused by Salmonella Typhi are generally the exception “Typhoid Mary” notorious carrier |
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salmonellosis treatment
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Adequate cooking kills bacterium
Antibiotic therapy is essential. Vaccine available for prevention of typhoid fever Vaccine 50% to 75% effective Surgical removal of gallbladder eliminates carrier state |
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1984 Rajneeshee Bioterror Attack
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Dalles, Oregon
Deliberate poisoning of salad bars in 10 restaurants to throw voting Infected 751 people, no fatalities |
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thyphoid mary
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Mary Mallon a cook
Asymptomatic carrier of Salmonella typhi Quarantined twice Refused to stop cooking Raises ethical questions as to the imprisonment of carriers |
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campylobacter
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gn rod
comma s shaped frequent cause of enterocolitis c.jejuni fecal oral route sources include cattle and chicken one drop of juice from raw chicken can contain infective dose |
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campylobacter treatment
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Prevention directed at proper treatment of water and food
Pasteurization of drinks and proper cooking and handling of raw food Most cases of campylobacteriosis subside without antimicrobial treatment in about 10 days Erythromycin recommended for severe cases |
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rotaviral gastroenteritis
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rotavirus
dbl walled capsid dsrna genome reovirus family fecal oral route |
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rotaviral symptoms
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Vomiting
Slight fever Profuse watery diarrhea Symptoms generally gone within a week Replacement of fluids crucial Death can occur from dehydration |
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rotaviral gastro epid
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infects wide variety of wild and domestic animals not infectious to humans
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rotaviral treatment
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Prevention directed at
Hand washing Disinfectant use Replacement of fluids |
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norovirus
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Norovirus
Small Nonenveloped Single stranded RNA genome Belongs to calcivirus family |
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norovirus symptoms
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Nausea
Vomiting Watery diarrhea Symptoms generally subside in 12 to 60 hours |
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norovirus patho
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Infects epithelium of upper small intestine
Epithelium generally recovers in approximately 2 weeks |
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norovirus epid
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Transmission via fecal-oral route
Sometimes contracted from eating shellfish Outbreaks often occur in institutions, cruise ships, etc. through contaminated food or water Incubation period 12 to 48 hours Infected individuals eliminate virus in feces |
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norovirus treatment
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Prevention
Hand washing Use of disinfectants No vaccine No proven antiviral medication |
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hepatitis a
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ss rna genome
ingestion of contam water or food fecal oral route virus reaches liver byunknown route |
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hepatitis a sypmtoms
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Fatigue
Fever Loss of appetite Nausea Right side abdominal pain Dark colored urine and clay colored feces Jaundice vaccination of 1995 |
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hepatitis b
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dsdna genome
symptoms more sever than hep a hbv spread mainly by blood products and semen sexual intercorse responsible vaccine in 1980s |
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hepatitis c
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ssrna genome
trans via contact w infected blood most develope chornic infections no vaccine for hcv develope cirrhosis or liver cancer no vaccine |
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giardiasis
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giardia lamblia mastigophora
giardiasis Transmission: ingestion of cyst in fecally contaminated food and water, contaminated streams (chlorination doesn’t kill cysts; boiling and filtration works), day-care centers, mental hospitals, male homosexuals (oral-anal contact) |
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trophozoite
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adheres to small intestinal wall via sucking disk and interferes with fat absorption
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giardiasis symptoms
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Non-bloody, foul-smelling diarrhea with abdominal cramps
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cryptosporidiosis
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c.parvum
ingestion of oocysts in fecally contaminated water Short term, mild diarrhea Chronic watery diarrhea in immune compromised individuals (AIDS patients) Important opportunistic infection |
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entamoeba histolytica
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Diarrhea ranging from mild asymptomatic disease to severe dysentery
May invade the intestinal mucosa causing erosions (10% of infected individuals) May penetrate potal blood circulation forming abscesses in the liver and lung and often death |
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normal flora of genitourinary system
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lower urethra lactobacillus staphy
corynebacterium strepto number of bact =uti resitance depends on hormonal status in female genital tract |
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bacterial cystitis
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inflamm of bladder
Complications include pyelonephritis Infection of the kidney |
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bacterial cystitis symptoms
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Abrupt onset
Burning pain on urination Urgent sensation to void Cloudy urine Odor May have pale red color Due to presence of blood Tenderness Some cases asymptomatic Especially among children and elderly |
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bacterial cystitis
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Infection usually originates from normal intestinal flora
E. coli most common cause (accounts for 80% to 90% of cases in women) 70% of all bladder infection cases S. saprophyticus (5-10% in younger women) Catheters often lead to chronic infections Often with multiple species of intestinal flora ( Pseudomonas, Serratia, Enterococcus) |
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bacterial pathogenesis
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Organisms reach bladder by ascending from urethra
Bacteria attach to receptors on bladder lining Pyelonephritis occurs when bacteria ascend ureters and cause damage to kidneys |
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bacterial pathogenesis treatment
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Antimicrobial therapy with appropriate antibiotic
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bacterial vaginosis
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Cause or causes unknown
Decrease in vaginal lactobacilli Increase in Gardnerella vaginalis |
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bacterial vaginosis symptoms
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Thin, grayish-white vaginal discharge
Can be slightly bubbly pungent fishy odor odor more distressing than vaginal discharge strong odor due metabolic products produces vaginal anaerobes |
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bacterial vaginosis patho
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Key changes include
Decrease in vaginal acidity Derangement of normal vaginal flora Increased number of sloughed vaginal cells Called “clue cells” Vaginal epithelial cells covered with bacteria |
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bacterial vaginosis epid
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Epidemiology incomplete
Due to lack of causative agent Disease most common among sexually active women |
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bacterial vaginosis treatment
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No proven prevention
Treatment of male sexual partners does not prevent recurrences Metronidazole effective treatment |
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vulvovaginal cadidasis
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Candida albicans
Part of normal flora in approximately 35% of women |
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vulvovaginal cadidiasis symptoms
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Most common symptoms include
Itching Burning Scant vaginal discharge White in curd-like clumps Involved area usually red and swollen |
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vulvo cadi patho
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Normally causes no symptoms
Due to balance between organism and normal vaginal flora When balance upset fungi multiply without restraint Cause inflammatory response and symptoms |
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vulvo cadi epid
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Disease not spread person to person
Generally not sexually transmitted |
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vulvo cadi treatment
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Prevention directed at minimizing use and duration of antibiotic therapy
Intravaginal treatment with antifungal medication usually effective |
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gonorrhea symptoms
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Incubation period 2 to 5 days post exposure
Asymptomatic infection can occur in both sexes In men symptoms characterized as urethritis with Pain on urination Discharge from penis In women symptoms are Painful urination Mild discharge Women more likely to be asymptomatic carriers |
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gonorrhea patho
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Attach to non-ciliated epithelial cells via pili
Particularly of the urethra, uterine cervix, pharynx, and conjunctiva IgA protease Bacterial proteins bind CD4 lymphocytes Prevents activation of immune response Antigenic variation (pilli) allows escape from antibody Untreated disease in men can lead to complications including Urinary tract infections Orchitis (inflammation of one or both of the testicles) sterility |
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gonorrhea in women
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Organism thrives in cervix and fallopian tubes
15% to 30% of untreated women develop pelvic inflammatory disease (PID) Scar tissue formation in fallopian tubes lead to increased risk of ectopic pregnancy and sterility |
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gonorrhea in newborns
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Opthalmia neonatorum
Gonococcal conjunctivitis of the newborn Acquired from infected birth canal Prevented with silver nitrate or erythromycin given within 1 hour of birth |
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gonorrhea treatment
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Prevention directed at
Abstinence Monogamous relationship Constant use of condoms No vaccine available Fluoroquinolones and cephalosporins effective against 95% of strains |
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chlamydial genital system infections
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Chlamydia trachomatis
Spherical Obligate intracellular bacterium Approximately eight types responsible for STD most common sexually transmitted bacterial disease in the United States |
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chlamydial genital system infection symptoms
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Generally appear in 7 to 14 days
In men Thin grayish-white discharge from penis Sometimes painful testes usually symptomatic (75%) In women Increased vaginal discharge Often painful urination Abdominal bleeding Upper and lower abdominal pain Women often asymptomatic |
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chlamydia life cycle
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In men
Infection spreads from urethra to tubules Results in acute swelling in women infection commonly involves uterus and fallopian tubes pid ectopic prenancy or sterile |
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chlamydia epid
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Non-sexual transmission also occurs
Major source is non-chlorinated swimming pools Newborns contract conjunctivitis much like with gonorrhea Number of reported cases tend to rise each year 14% of sexually active high school and college women are asymptomatic carriers |
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chlamydia treatment
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Abstinence
Monogamous relationship Use of condom All sexually active women should get tested annually Semi annually if multiple partners Azithromycin effective single dose treatment Tetracycline and erythromycin are less expensive alternatives |
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syphilis
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Treponema pallidum
Motile spirochete Cannot be cultivated in laboratory Darkfield microscopy used for identification |
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syphilis patho
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Organism penetrates mucous membranes and abraded skin
Very low infecting dose Less than 100 organisms Organism multiplies in localized area Spreads to lymph nodes and bloodstream Three stages of disease Primary stage Secondary stage Tertiary stage |
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syphilis primary stage
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Characterized by hard chancre from inflammatory response
Chancre disappears in 2 to 6 weeks with or without treatment |
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syphilis secondary
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Bacteria multiply and spread via blood throughout body
Disease can be transmitted by kissing at this stage Rash on the palms and soles of feet Stage may last weeks to months Followed by extended latent period |
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syphilis tertiary stage
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Not all individuals develop tertiary syphilis
Stage characterized by gumma Necrotizing mass of tissue Patient no longer infectious If organisms persist in walls vital organs can cause life threatening condition Blindness Metal illness Stroke Numerous nervous system disorders Congenital syphilis Organism readily crosses placenta Most dangerous during fourth month miscarriage still birth deformities of face teeth other body parts |
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syphilis epid
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No animal reservoir
Usually transmitted via sexual contact Elimination within reach in U.S. Depends on identification and treatments of cases Blood test can be used as potential screening method |
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syphilis treatment
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No vaccine
Safe sex practices decrease risk Prompt identification and treatment of infected individuals and contacts Primary and secondary stages effectively treated with antibiotics Antibiotics somewhat effective in tertiary but must be treated longer |
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genital herpes
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Usually herpes-simplex virus type 2
DNA virus Disease recurrence due to latent virus |
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genital herpes symptoms
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Begin 2 to 20 days post infection
Genital itching and burning Pain Primarily in women Blisters develop on genitals Blisters heal spontaneously Most patients will have recurrence |
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genital herpes patho
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Blisters created by infected epithelial cells
Blisters rupture to produce painful ulcerations Latency follows ulceration Viral DNA exists in cell in non-infectious form within nerve cell Recurrence is due to replication of complete virions from latent DNA Viruses re-infect area supplied by nerve Congenital herpes can pose serious risk for newborn 1 in 3 newborns contract herpes if mother has primary infection at time of birth Can be debilitating and potentially lethal |
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genital herpes treatment
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Avoidance of sexual intercourse during active symptoms
Use of condom and spermicide reduce but do not eliminate transmission There is no cure for genital herpes Medications such as acyclovir and famciclovir can decrease severity |
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genital warts and cervical cancer
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Human papillomavirus (HPV)
Non-enveloped, double stranded DNA virus Nearly 100 types of HPV 30 are transmitted sexually 15 types strongly associated with cancer |
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genital warts and cervical cancer symptoms
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Individual may be asymptomatic
Genital warts most easily recognized symptom Often appear on the head or shaft of penis, at the vaginal opening or around anus Warts can become inflamed or bleed Precancerous lesion on cervix often asymptomatic |
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papillomavirus genital warts and cervical cancer patho
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HPV enters and infects deeper layers of tissue through abrasions
May lead to latent infection Mechanism of wart formation is unknown Warts usually appear about 3 months after infection Removal of warts does not eliminate virus HPV can be transmitted to fetus through birth canal Most cervical cancers associated with HPV |
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pap warts cervical cancer epid
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HPV readily spread through sexual contact
Asymptomatic carriers can infect others with HPV HPV most common reason for abnormal Pap smear History of multiple sex partners is most important risk factor for acquiring HPV Warts can develop in the mouth via oral sex |
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pap warts cervical cancer
treatment |
Condom use can help decrease chance of transmission
Women should have Pap smear annually Can identify precancerous lesions Abnormal growth can be removed preventing development of cancer Warts can be removed via laser treatment or freezing with liquid nitrogen There is an effective vaccine available |
