Bacteria Flashcards
(49 cards)
1
Q
Enterobacter
A
Enterobactor = hospital acquired infection
- Gram negative enteric rod
- Motile
- Part of normal intestinal flora
- Can cause hospital acquired infections
2
Q
Staphylococcus epidermidis
A
Staphylococcus epidermidis = skin contaminant of blood cultures, biofilm on prosthetics
- Gram positive cocci
- Coagulase negative
- Normal body flora on the skin
- Frequent skin contamination of blood cultures
- Sometimes have to draw from 2 sites to confirm whether contaminant or true bacteremia
- Causes infections of:
- Urine catheters
- Dialysis catheters
- IV lines
- Prosthetic joints and heart valves - biofilm helps bacteria to bind
3
Q
Streptococcus agalactia
A
Streptococcus agalactiae = Group B, women can carry vaginally, pass onto baby, cause neonatal meninigitis (think lactate = pregnancy)
- Gram positive cocci
- Group B beta hemolytic
- 25% of women carry this bacteria vaginally
- Low virulence for adults (can cause UTI) but very dangerous for babies
- Can be passed to baby during delivery
- Can cause neonatal meninigits, pneumonia, and sepsis
- Pregnant women are screened at 35-37 weeks gestation
4
Q
Rickettsia rickettsii
A
Rickettsia rickettsii = Rocky mountain spotted fever, tick bite, palmar rash
- Obligate intracellular bacteria
- Can survive only in animal cells
- Rocky mountain spotted fever
- 1000 cases per year in U.S.
- Spring and summer
- Wood or dog tick bite
- Fever, conjunctival redness, headache, palmar rash
5
Q
Enterotoxigenic Escherichia coli
A
Enterotoxigenic Escherichia coli = traveler’s diarrhea, rice water diarrhea
- Gram negative enteric rod
- Traveler’s diarrhea
- Virulence factors
- Pili
- Exotoxin
- Osmostic pull - electrolyte loss and dehydration
- Rice watery diarrhea
6
Q
Bordetella pertussis
A
Bordetella pertussis = whooping cough
- Gram negative rod respiratory
- Causes whooping cough
- Give DTaP vaccine - introduced in 1940’s
- Booster vaccine recommended
- Virulence factors allow it to bind to ciliated epithelial cells of trachea and bronchi and destroys them
- Highly contagious, spread via respiratory secretions
- Symptoms of whooping cough:
- Catarrhal stage - fever, runny nose, cough
- Paroxysmal stage - non productive cough with “whoop” sound
- Convalescent stage - attacks less frequent, no longer contagious
- Erythromyxin recommended in first two stages
7
Q
Clostridium perfringens
A
Clostridium perfringens = gas gangrene, necrotizing fasciitis
- Gram positive spore forming rod
- Causes gas gangrene (necrotizing fasciitis)
- Spores found in soil and mature in anaerobic conditions
- Spores produce gas and release exotoxins
- Three classes of infection
- Cellulitis - causes crepitus due to pockets of gas
- Myonecrosis - trauma to muscle
- Diarrhea - spore germinate in food
8
Q
Clostridium tetani
A
Clostridium tetani = tetnus, spastic paralysis
- Gram positive spore forming rod
- Causes tetnus
- Can follow skin trauma by any object contaminated with spores
- Spores are found in soil and animal feces
- Necrotic tissue forms anaerobic environment and exotoxin is released
- Leads to contraction of skeletal muscle (spastic paralysis)
- Tetanus immune globin neutralizes toxin
- Booster vaccines given every 10 years
9
Q
Enterohemorrhagic / Shiga toxin producing Escherichia coli
A
Enterohemorrhagic / Shiga toxin producing Escherichia coli = bloody diarrhea (hemorrhagic colitis), instestinal epithelial cell death, hamburger meat strain 0157:H7
- Gram negative enteric rod
- Hemorrhagic colitis - bloody diarrhea with cramps
- Virulence factors
- Pili
- Exotoxin - same mechanism of action as the Shigella toxin
- Inhibits protein synthesis, causing intestinal epithelial cell death
- Strain 0157:H7 linked to hamburger meat
10
Q
Neisseria gonorrhoeae
A
Neisseria gonorrhoeae = gonorrhea, 2nd most reported STI, neonatal conjunctivitis, PID
- Gram negative cocci
- Causes gonorrhea
- 2nd most reported STI
- Virulence factors
- Pili
- Other proteins allow binding to cells
- Causes:
- Neonatal conjunctivitis
- Pelvic inflammatory disease (PID), which is infection of the:
- Uterus - endometritis
- Fallopian tubes - salpingitis
- Ovaries - oophoritis
11
Q
Mycoplasma pneumoniae
A
Mycoplasma pneumoniae = atypical walking pneumonia, streaky infiltrate in CXR, most common cause of bacterial bronchitis and pneumonia in teens / young adults
- Bacteria without cell walls
- Mild self limited bronchitis or pneumonia
- Atypical / walking pneumonia
- Most common cause of bacterial bronchitis and pneumonia in teens and young adults
- 2-3 week incubation period
- Presents with fever, sore throat, malaise, and persistent dry cough
- CXR shows streaky infiltrate
Mycoplasma pneumoniae = atypical walking pneumonia, streaky infiltrate in CXR, most common cause of bacterial bronchitis and pneumonia in teens / young adults
12
Q
Clostridium difficile
A
Clostridium difficile = C. diff, pseudomembranous colitis, diarrhea after taking abx
- Gram positive spore forming rod
- Causes pseudomembranous colitis
- This is what causes diarrhea after taking broad spectrum abx
- Abx eradicates normal flora, allowing C. diff to infect
- Releases exotoxins causing diarrhea, cramping, and fever
- In a coloscopy see red inflamed mucosa with white exudate
- Stool sample confirms dx
13
Q
Francisella tularensis
A
Francisella tularensis = Ddx for bubonic plague, ulceroglandular disease, rabbits, ticks, deerflies
- Gram negative rods zoonotic
- In differential diagnosis of bubonic plague
- Most commonly acquired from handling infected fabbits and bits of ticks or deerflies
- Causes:
- Ulceroglandular disease
- Pneumonia
- Diagnosis depends on clinical picture and antigen/antibody testing
14
Q
Leptospira
A
Leptospira = dog, rat, livestock, and wild animal urine, penetrate abraded skin or mucous membranes
- Spirochetes
- Long, then aerobic spirochetes
- Have hook at one or both ends
- Found all over the world in urine of dogs, rates, livestock, and wild animals
- Spirochetes penetrate abraded skin or muscous membranes
15
Q
Legionella pneumophilia
A
Legionella pneumophilia = Legionnaire’s disease, community acquired pneumonia, AC vents, hot tubs, shower heads, produce misters
- Gram negative rod respiratory
- Causes Legionnaire disease and Legionaire pneumonia
- Lives in water environments
- Contaminated water is aerosolized and inhaled
- A/Cs
- Hot tubs
- Shower heads
- Produce misters
- Survives and replicates intracellularly
- Common cause of community acquired pneumonia
16
Q
Pasteurella multocida
A
Pasteurella multocida = dog or cat bite
- Gram negative rods zoonotic
- Colonizes in mouths of dogs and cats
- Causes the most frequent wound infection following a dog or cat bite
- May not be appropriate to suture wound because that would provide perfect environment for bacteria
- Can tx with abx
17
Q
Helicobacter pylori
A
Helicobacter pylori = most common cause duodenal ulcers, 2nd leading cause gastric ulcers
- Gram negative enteric rod
- Most common cause of duodenal ulcers
- 2nd leading cause of gastric ulcers
18
Q
Campylobacter jejuni
A
Campylobacter jejuni = bloody, loose diarrhea, one of the three most common causes of diarrhea in the world
- Gram negative enteric rod
- One of the three most common causes of diarrhea in the world
- Source is wild animals, domestic animals, and poultry
- Often via contaminated water
- Organisms invade lining of small instestine
- Blood, loose diarrhea
19
Q
Moraxella catarrhalis
A
Moraxella catarrhalis = otitis media, sinusitis, bronchitis, and pneumonia
- Gram negative coccobacillus
- Same phylogenic family as Neisseria
- Causes three major conditions
- Otitis media
- Sinusitis
- Bronchitis / pneumonia
20
Q
Proteus mirabilis
A
Proteus mirabilis = UTI, hospital acquired infection
- Gram negative enteric rod
- Very motile
- Present in colon, soil, and water
- Commonly causes:
- UTI
- Hospital acquired infection
21
Q
Enterococci
A
Enterococci = Group D, UTI, bacteremia, endocarditis, normal flora in gut
- Gram positive cocci
- Group D with variable hemolysis
- Normal bowel flora in humans
- Effects:
- UTIs
- Biliary tract infections
- Bacteremia
- Endocarditis
- Weak, hospitalized patients are at risk
- Bacteria has become high resistant to abx
22
Q
Staphylococcus saprophyticus
A
Staphylococcus saprophyticus = leading cause of UTIs
- Gram positive cocci
- Found in genital tract of women
- Can ascend into bladder
- Leading cause of UTIs
23
Q
Streptococcus pyogenes
A
Streptococcus pyogenes = Group A, classic strep throat
- Gram positive cocci
- Group A - Lancefield antigen A present
- Beta hemolytic - lyses RBCs completely
- Causes:
- Pus producing
- Scarlet fever
- Rheumatic fever
- Post streptococcal glomerulonephritis (damage to kidneys from strep)
- Cellulitis
- Impetigo
- Rapid step detects group A antigen
- PCN treats effectively
24
Q
Atypical mycobacteria
A
Mycobacterium avium complex (MAC) = most common cause of atypical mycoplasma lung disease, causes opportunisitc infection in patients with AIDS and low CD4 count
- Acid fast bacteria
- Found in soil and water
- Healthy people rarely develop disease despite daily exposure
- Can cause broad range of presentations from completely asymptomatic to chronic pneumonia
-
Mycobacterium avium complex (MAC)
- Group of related bacteria belonging to genus Mycobacterium
- Causes opportunisitc infection in patients with AIDS and low CD4 count
- Most common cause of atypical mycoplasma lung disease
- Present clinically with fever, night sweats, diarrhea, and malaise
25
*Neisseria meningitidis*
***Neisseria meningitidis* = menigitis, petechial rash, college freshmen, military recruits**
* Gram negative cocci
* Also called meningococcus
* Very bad disease - causes limb loss!
* Causes
* Menigitis
* Meningococcemia - sepsis
* Virulence factors:
* Capsule
* Endotoxin
* Pili
* Spreads via respiratory secretions
* High risk groups
* Infants
* Military recruits (close quarters)
* College freshmen
* Endotoxin causes blood vessel desctruction
* Petechiae - tiny round red dots
* Petechial rash
26
*Staphylococcus aureus*
***Staphylococcus aureus* = MRSA, toxic shock syndrome, coagulase positive**
* Gram positive cocci
* Coagulase positive
* Produces toxin
* Causes:
* Abscesses
* Pyogenic (pus) infections
* Toxic shock syndrome
* Folliculitis
* Celluitis
* Bacterial conjunctivitis
Methicillian resistant Staphylococcus aureus (MRSA)
* Most Staphylococci are resistant to PCN due to production of penicillinase
* Methicillin has been known as a PCN resistant abx and was effect against Staphylococcus aureus until recently
* MRSA is a strain that has acquired multi drug resistance
* HA-MRSA (hospital)
* CA-MRSA (community)
27
*Salmonella*
***Salmonella* = lives in GI tract of animals, chicken, uncooked eggs, diarrhea**
* Gram negative enteric rod
* Differs from other enterics because it lives in GI tract of animals
* Always pathogenic
* Infects humans when there is contamination of food or water with animal feces
* Most commonly acquired from chickens and uncooked eggs
* Diarrhea
28
*Streptococcus pneumonia*
***Streptococcus pneumoniae* = pneumonia and otitis media**
* Gram positive cocci
* Alpha hemolytic
* Arranged in pairs - diplococci
* Major cause of:
* Pneumonia and meninigits in adults
* Otitis media in children
* Major virulence factor: polysaccharide capsule
* 35% of strains have developed high abx resistance
29
*Treponema pallidum*
***Treponema pallidum* = syphilis, MSM, HIV**
* Spirochetes
* Syphillis
* 60% of new cases are in men who have sex with men
* Associated with HIV coinfection (like TB)
* Penetrates mucous membranes by invading through abrasions
* Three clinical stages:
* Primary syphilis
* Painless chancre - firm painless lesion
* Highly infectious
* Resolves without scar - fools people into thinking the infection has been resolved
* Secondary syphilis
* Widespread rash
* Tertiary syphilis
* Inflammatory damage to organs
30
*Mycobacterium leprae*
***Mycobacterium leprae* = Leprosy (Hansen disease), grows better in cooler body temperatures closer to skin surface**
* Acid fast bacteria
* Causes leprosy (Hansen disease)
* 2 million people worldwife infected
* 100 new cases in U.S. per year
* Infection occurs via respiratory secretions or skin contact
* Grows better in cooler body temperatures closer to skin surface
31
*Bacillus cereus*
***Bacillus cereus* = food poisoning in rice and other grains**
* Gram positive spore forming rod
* Motile
* No capsule
* Causes food poisoning
* Spores on rice and other grains survive cooking
* Germination happens when rice is kept warm for hours
* Bacteria then germinate in the food releasing toxin
* Effects:
* Nausea
* Vomiting
* Diarrhea
* Abx do NOT help shorten the course of the disease
32
*Mycobacterium tuberculosis*
***Mycobacterium tuberculosis* = TB, HIV, caseous necrosis**
* Acid fast bacteria
* Causes TB
* 9 million new cases world wide
* 2 million deaths per year
* Spike in cases during the 1980's - conincided with AIDS epidemic
* People with HIV/AIDS lacked cell mediated immunity necessary for fighting TB
* Obligate aerobe - need oxygen
* Most commonly infects lungs where oxygen is plentiful
* Grows very slowly
* Can take up to 6 weeks to grow in culture
* The way it spreads and damages the body depends on the hosts' immune system
* First phase - inhaled bacteria cause local infiltration of cells
* Second phase (cell mediated immunicty) - eventually macrophages begin breaking up bacteria
* Macrophage attack causes destruction and necrosis of lung tissue, which looks like creamy cheese and is called **caseous necrosis**
* Intradermal injection of antigen particles from killed *M. tuberculosis* will cause skin swelling and redness
33
*Chlamydia trachomatis*
***Chlamydia trachomatis* = chlamydia, newborns given abx eye drops, PID**
* Primarily infects eyes and genitals
* Most common STI in U.S.
* Babies born to mother who are infected can develop conjunctivitis or pneumonia
* In the U.S., all newborns are given erythromycin eye drops
* Urethritis is usually contracted sexually
* PID
* PID shuffle
* Chandelier sign - cervical motion tenderness
* Can be asymptomatic, mild, go unnoticed and still cause infertility
* Coinfection is common (e.g. with gonorrhea)
34
*Streptococci viridan*
***Viridians - Streptococcus mutans* = dental infection**
* Gram positive cocci
* Most are alpha hemolytic
* Types:
* *Streptococcus mitis*
* *Streptococcus sanguinis*
* *Streptococcus mutans*
* Found in oropharynx and colon
* Exist in dental plaque, tongue, and siliva
* Causes 3 major types of infections
* Dental infections / caries - *Streptococcus mutans*
* Endocarditis
* Abscesses
35
*Ureaplasma urealyticum*
***Ureaplasma urealyticum* = lower UTI urethritis, dysuria, yellow discharge from urethra**
* Bacteria without cell walls
* Part of normal flora in 60% of healthy women
* Found in urine
* Can cause lower UTI urethritis
* Presents with dysuria and yellow discharge from urethra
* Other two bacteria that can cause urethritis:
* *Neisseria gonorrhea*
* *Chlamydia trachomatis*
36
*Brucella*
***Brucella* = brucellosis, not common in U.S. because cows are immunized and milk is pasteurized**
* Gram negative rods zoonotic
* Causes Brucellosis
* Humans acquire through direct contact with infected animal meat or milk products
* Not common in U.S. because cows are immunized and milk is pasteurized
* Penetrates skin, conjunctiva, lungs, or GI tract
* Lymphatic spread, intracelluar growth, blood, and organ invasion
37
*Haemophilus influenzae*
***Haemophilus influenzae* = meningitis, vaccine given to children, Hib**
* Gram negative rod respiratory
* 6 capsule types
* Type B (Hib) - causes meningitis
* Type B is assocated with more invasive disease
* meningitis
* epiglottitis
* septic arthritis
* otitis media
* respiratory disease
* HIB vaccine is given to children
38
*Borrelia burgdorferi*
***Borrelia burgdorferi* = Lyme disease, ticks, mice, deer, target rash**
* Spirochetes
* Causes Lyme disease
* Most common reported tick borne illness in U.S.
* White footed mouse and white tailed deer
* Early localized stage is 10 days after tick bite
* Target / bullseye rash
* Late stage can lead to chronic neurological damage
39
*Salmonella typhi*
***Salmonella typhi* = Tyhpoid Fever, survive inside other cells, lives in gallbladder of chronic carriers, Typhoid Mary**
* Gram negative enteric rod
* Causes Typhoid Fever (enteric fever)
* Invades intestinal epithelial cells
* Invades regional lymph nodes
* Can survive inside other cells
* Fever, headache, and abdominal pain
* Chronic carriers of *S. typhi* carry in gallbladder
* Typhoid Mary
40
*Vibrio cholera*
***Vibrio cholera* = cholera, rice water diarrhea**
* Gram negative enteric rod
* Curved gram negative rod with single flagellum
* Causes cholera
* Source is fecally contaminated water
* Bacteria multiply in intestine and cause same disease as ETEC
* Bacteria attach to cells and release cholera toxin
* Abrupt onset of rice water diarrhea
* Death by dehydration
41
*Shigella*
***Shigella* = preschool, nursing homes, invade intestinal epithelium, bloody diarrhea with WBCs**
* Gram negative enteric rod
* Non motile
* Always a pathogen
* Humans are only host
* Transmitted fecal oral route via fecally contaminated water and hand to hand contact
* Preschool children and nursing homes often affected
* Similar to enteroinvasive *E. coli* because both invade instestinal epithelium
* Damaged colon cannot reabsorb fluids and causes diarrhea with bright red blood and WBCS
42
* Yersinia enterocolitica*
* *
**Y*ersinia enterocolitica* = acute gastroenteritis, grows in cold**
* Gram negative rods zoonotic
* Acute gastroenteritis
* Clinical presentation identical to *Salmonella and Shigella* infections
* Animals are a major source
* Humans ingest contaminated food or water
* Can survive and grow in cold
43
*Bacillus anthracis*
***Bacillus anthracis* = anthrax, spores sent in mail, causes maligant pustule from exotoxin**
* Gram positive spore forming rod
* Causes anthrax
* Has an anti-phagocytic capsule
* Common in animals, rare in humans
* Primarily affects cows and sheep
* Humans become exposed to spores from infected animals, soil, or hides/wool
* Humans exposed in 2001 when spores sent in mail
* Once spore is introduced to lungs, skin, or intestine it starts making toxins
* High mortality rate assoicated with pulmonary inhalation
* Most common route of entry is through the skin
* **Exotoxin** causes tissue necrosis
* Black eschar skin lesion called **maligant pustule**
* Tx with abx
44
*Listeria monocytogenes*
***Listeria monocytogenes* = deli meats and soft cheese, neonatal menigitis**
* Gram positive non spore forming rod
* Has flagella
* Pregnant women, elderly, and immunocompromised at high risk for infection
* Bacteria can infect fetus and cause neonatal menigitis
* Contaminated foods: deli meat and soft cheeses
45
*Yersinia pestis*
***Yersinia pestis* = Bubonic plague, hemorrhage under skin is black death, rats, fleas**
* Gram negative rods zoonotic
* Causes the Bubonic plague
* Fleas bite rats that have the disease then bite humans
* Or humans can touch dead infected rodent
* Can be contracted during camping, hunting, and hiking
* Spreads to blood, lymph nodes, and organs
* Hemorrhage occurs under the skin - black death
46
*Clostridium botulinum*
***Clostridium botulinum* = flaccid paralysis, honey, canned vegetables, floppy baby syndrome**
* Gram positive spore forming rod
* Spores in soil containminate vegetables and meat
* Spore germinate in food and make toxin when foods are canned without proper sterilization
* Produces neurotoxine and flaccid paralysis
* Neurotoxin blocks release of acetycholine in autonomic nervous system
* Associated with eating smoked fish or home canned vegetables
* Associated with honey in infants
47
Enteroinvasive *Escherichia coli*
**Enteroinvasive *Escherichia coli* = plasmid virulence factor, invades through wall of intestine, bloody diarrhea with WBCs**
* Gram negative enteric rod
* Same disease state as that produced by *Shigella*
* Virulence factor - **plasmid** enables bacteria to invade through epithelial cells
* Invades through wall of intestine
* Bloody diarrhea with WBCs
48
*Klebsiella pneumonia*
***Klebsiella pneumonia* = red currant jelly sputum, sepsis, UTI, pneumonia**
* Gram negative enteric rod
* Encapsulated and non motile
* 2nd most common cause of sepsis in hospitals (after *E. coli)*
* Causes UTI in hospitilized patients with Foley catheter
* Pneumonia in debilitated patients - 50% have red currant jelly bloody sputum
49
*Corynebacterium diphtheriae*
***Corynebacterium diphtheriae* = diphtheria, gray plaque in pharynx**
* Gram positive non spore forming rod
* Causes diphtheria
* Colonizes in pharynx
* Forms gray plaques in pharynx
* Releases toxin in blood damaging heart
* Tx consists of antitoxin, PCN, or DPT vaccine
