Intro to Bacteria Part 2 Flashcards
1
Q
Three major species of Staphylococci
A
S. aureus, S. epidermidis, S. saprophyticus
2
Q
S. aureus on blood agar
A
gold pigment, B-hemolytic
3
Q
Staph catalase test
A
all positive
4
Q
Which type of staph is coagulase positive?
A
S. aureus, elaborates coagulase (activates prothrombin)
5
Q
S. aureus virulence proteins
A
Protein A (protects from opsonization), coagulase (fibrin forms around bacteria), hemolysins, leukocidins, penicillinase (B-lactamase), penicillin binding protein
6
Q
S. aureus proteins that degrade tissues
A
hyaluronidase (proteoglycans), staphylokinase (lyses fibrin), lipase, protease
7
Q
S. aureus exotoxins
A
exfoliation - scalded skin syndrome
enterotoxins - vomiting and diarrhea
TSST-1 - super antigens that bind to MHCII causing massive T cell response
8
Q
Diseases caused by release of S. aureus exotoxins
A
Gastroenteritis, TSS, scalded skin syndrome
9
Q
Diseases caused by direct organ invasion by S. aureus
A
pneumonia, meningitis, osteomyelitis, acute bacterial endocarditis, septic arthritis, skin infections, sepsis, UTI
10
Q
Presentation of gastroenteritis
A
nausea, vomiting, diarrhea, abd pain, fever lasting 12-24 hours
11
Q
Pathology of TSS
A
penetrates vaginal mucosa and stimulates TNF and IL1
12
Q
Presentation of TSS
A
high fever, N/V/D, diffuse erythematous rash, desquamation of palms and soles
13
Q
Presentation of staphylococcal scalded skin syndrome
A
exfoliative toxin A and B, neonates typically affected, cleavage of middle epidermis
14
Q
S. aureus pneumonia presentation
A
CA-pneumonia; follows viral influenza with onset of fever, chills, lobar consolidation, destruction of lung parenchyma
15
Q
Meningitis, cerebritis, Brain abscess presentation
A
high fever, stiff neck, HA, coma, obtundation, focal neurologic signs
16
Q
Osteomyelitis presentation
A
boys < 12 yo, warm, swollen tissue over bone with system fever and shakes
17
Q
Acute endocarditis presentation
A
destruction of heart valves with high fever, chills, myalgias; may lead to vegetations on valves and embolization to lungs or brain
18
Q
Septic arthritis presentation
A
acutely painful red swollen joint with decreased ROM, often occurs in peds and elderly
19
Q
Impetigo
A
small vesicles lead to pustules; honey-colored crust, wet, flaky
20
Q
Cellulitis
A
tissue becomes hot, red, shiny, and swollen
21
Q
Local abscesses
A
collection of pus
22
Q
furuncle
A
infection of follicle that penetrates into subcutaneous tissues
23
Q
Carbuncles
A
furuncles bore through to produce multiple contiguous painful lesions communicating under the skin
24
Q
Blood and Cath infections
A
S. aureus can migrate from the skin and colonize catheters resulting in bacteremia, sepsis, septic shock
25
MRSA
multi-drug resistant bug, mecA encodes penicillin binding protein 2A that avoids penicillin damage
26
CA-MRSA
often occurs among sports teams; skin and soft tissue infections in close contact settings, spreads much more quickly than HA-MRSA, still tends to be susceptible to some oral abx
27
S. epidermidis metabolism
catalase-positive, coagulase-negative, facultative anaerobe
28
Common source of S. epidermidis infection
foley catheter, IV line
29
S. epidermidis virulence
polysaccharide capsule that adheres to variety of prosthetic devices, highly resistant to abx
30
Common S. epidermidis infections
prosthetic joints, prosthetic heart valves, sepsis from IV lines, UTI, skin contaminant in blood culture
31
S. saprophyticus
leading cause of UTI second to E. coli among females, coagulase negative
32
Bacillus characteristics
G+, aerobic, spore forming rods
33
Bacillus anthracis capsule
only bacterium with capsule composed of protein
34
How is Bacillus anthracis acquired?
direct contact with infected animals or soil
35
How are Bacillus anthracis spores activated?
phagocytosed by macrophages, germinate and then become active
36
Cutaneous anthrax
exotoxin causes localized tissue necrosis, painless round black lesion with rim of edema (malignant pustule)
37
Pulmonary anthrax
spores taken up macrophages in lungs and transported to hilar and mediastinal LN where they germinate, mediastinal hemorrhage occurs and results in mediastinal widening and pleural effusions
38
GI anthrax
often results in death, exotoxin causes necrotic lesion with intestine, pt presents with vomiting, abd pain and bloody diarrhea
39
Three proteins of exotoxin of B. anthracis
Edema factor, protective antigen, lethal factor
40
Edema factor
active A subunit of exotoxin, increases cAMP which impairs neutrophil function and causes edema
41
Protective antigen
promotes entry of EF into phagocytic cells
42
Lethal factor
zinc metalloprotease that inactivates protein kinase, stimulates release of TNF and IL1
43
Bacillus cereus vs. B. anthracis
B. cereus is motile, non-encapsulated, resistant to penicillin
44
Major infection associated with B. cereus
food poisoning
45
Enterotoxins secreted by B. cereus
heat-labile toxin, heat-stable toxin
46
Heat-labile toxin causes what sxs
nausea, abd pain, diarrhea lasting 12-24 hours
47
Heat-stable toxin causes what sxs
nausea, vomiting, limited diarrhea
48
Clostridium characteristics
G+ spore-forming rods, anaerobic
49
Clostridium is responsible for what diseases?
botulism, tetanus, gangrene, pseudomembranous colitis
50
C. botulinum produces...
lethal neurotoxin that blocks the release of Ach and causes flaccid paralysis
51
Adult Botulism is acquired from
smoked fish or home-canned vegetables
52
Presentation of adult botulism
afebrile, bilateral cranial nerve palsies, diplopia, dysphagia, general muscle weakness, respiratory paralysis and death
53
Infant botulism is acquired from
food contaminated with C. botulinum spores
54
Presentation of infant botulism
constipation 2-3 days, difficulty swallowing and muscle weakness; "floppy baby"
55
Presentation of wound botulism
fever, high white count, cranial nerve palsies, respiratory paralysis
56
Clostridium tetani
causes tetanus, releases tetanospasmin
57
tetany
sustained contraction of skeletal muscles
58
Presentation of tetany
severe muscle spasms especially in jaw, risus sardonicus (grotesque grin)
59
C. perfringens infections
causes gas gangrene; cellulitis, clostridial myonecrosis, diarrheal illness
60
Cellulitis/wound infection by C. perfringens
grows and damages local tissue; moist, spongy, crackling consistency to skin (crepitus)
61
Clostridial myonecrosis (C. perfringens)
C. perfringens in muscle will secrete exotoxins that destroy adjacent muscle, seen on CT as pockets of gas in muscles and subcutaneous tissue
62
Diarrheal Illness (C. perfringens)
toxin production in gut and subsequent watery diarrhea, can lead to hemorrhagic necrosis of jejunum
63
Clostridium difficile
associated with abx-associated pseudo-membranous colitis following use of broad spectrum antibiotics
64
Toxin A C. diff
causes diarrhea
65
Toxin B C. diff
cytotoxic to colonic cells
66
Diagnostic tests for C. diff
PCR for toxin A and B, Enzyme immunoassay
67
Non-spore forming gram positive bacteria commonly present in what patients
pediatric patients
68
Corynebacterium diphtheriae
responsible for diphtheria; colonizes pharynx, releases toxins into blood stream that damages heart and neural cells
69
Clinical presentation of Corynebacterium diphtheriae
child with sore throat and fever, dark inflammatory exudate on child's pharynx
70
Culture medium for C. diphtheriae
potassium tellurite agar (gray to black colonies), Loeffler's coagulated blood serum
71
Diphtheria antiotoxin
inactivates circulating toxin that has not reached target tissue
72
DPT vaccine
formalin inactivated diphtheria toxin
73
Similarity between Grp A B-hemolytic strep and C. diphteriae
must be lysogenized by bacteriophage to produce toxin
74
Rhodococcus equi
G+, aerobic nonmotile, bacillary bacteria; typically infects animals; can form necrotizing pneumonia when inhaled
75
Characteristic presentation of Rhodococcus equi
upper lobe lung nodules that form air-fluid levels, may stain partially acid-fast
76
Listeria monocytogenes characteristics
facultative anaerobe, non-spore forming G+ rod
77
How is L. monocytogenes grown?
low temperatures
78
L. monocytogenes virulence factor
listeriolysin O, allows bacteria to escape phagolysosomes and avoid intracellular killing
79
Who is most at risk for L. monocytogenes?
Pregnant women, neonates, elderly, immunocompromised
80
L. monocytogenes in pregnant women
infection occurs in third trimester, fetus will be infected and may die or be born prematurely with active infection
81
How may L. monocytogenes be acquired?
contaminated foods such as soft cheeses and cold cuts, through vaginal colonization
82
L. monocytogenes in neonates
neonatal meningitis presenting 2 weeks post-partum
83
L. monocytogenes in elderly and immunocompromised
second most common cause of meningitis
84
L. monocytogenes as a facultative intracellular organism
bacteria able to survive inside or outside of cells, in immunocompetent pts it will be killed via cell-mediated immunity
85
Major pathogenic G- cocci
N. meningitidis, N. gonorrhoeae
86
N. meningitidis major disease association
meningitis
87
N. meningitidis capsule
antiphagocytic polysaccharide capsule
88
N. meningitidis endotoxin
blebs of endotoxin cause blood vessel destruction and sepsis (petechiae)
89
N. meningitidis IgA1 protease
cleaves IgA in half
90
N. meningitidis and iron
bacteria can extract iron from transferrin
91
N. meningitidis pili
allow attachment to human NP cells and undergo antigenic variation to avoid attach by immune system
92
N. meningitidis carriers
bacteria is a part of their normal flora of the nasopharynx, develop anti-meningococcal antibodies
93
N. meningitidis high risk groups
infants 6mo to 2 yo, army recruits, college freshmen
94
How does N. meningitidis spread?
via respiratory secretions
95
Classic clue to invasive meningococcal infection
petechial rash, due to release of endotoxin
96
Meningococcemia
abrupt onset of fevers, chills, arthralgia, muscle pains, petechial rash
97
Fulminant meningococcemia
Waterhouse-Friderichsen syndrome; bilateral adrenal gland hemorrhage, abrupt hypotension and tachycardia, DIC, coma, death
98
Meningitis
usually infants <1 yr; fever, vomiting, irritability, lethargy, bulging anterior fontanelle, possibly a stiff neck
99
Medium for N. meningitidis growth
Thayer-Martin VCN (chocolate agar with antibiotics); vancomycin, colistin, nystatin; increased CO2
100
Nisseria and maltose metabolism
meningitidis will produce acid, gonorrheae cannot
101
Second most common STI
gonorrhea
102
N. gonorrheae pili
have hypervariable aa sequences, protect bacteria from abx and our own immune system, prevent phagocytosis
103
N. gonorrheae outer membrane protein porins
promote invasion into epithelial cells
104
N. gonorrheae Opa proteins
promote adherence and invasion into epithelial cells
105
Presentation of gonorrhea in men
urethritis, painful urination and purulent discharge; epididymitis, prostatitis, urethral strictures
106
Rectal gonococcal infection presentation
MSM, anal pruritis, tenesmus, rectal bleeding and purulent discharge
107
Presentation of gonorrhea in women
most likely to be asymptomatic with minimal urethral discharge although they may develop urethritis; reddened and friable cervix, lower abd pain, dyspareunia, purulent vaginal discharge
108
Pelvic inflammatory disease
infection of uterus, fallopian tubes, or ovaries resulting from gonococcal infection of cervix; pt will present with ffever, lower abd pain, abn menstrual bleeding, cervical motion tenderness
109
PID and menses
menstruation allows bacteria to spread upward, most cases present within one week of menstruation, IUD will also increase risk
110
Complications of PID
sterility, ectopic pregnancy, abscesses, peritonitis, peri-hepatitis
111
Gonococcal bacteremia presentation
bacteria invades blood stream and manifests as fever, joint pains, skin lesions; further complications include pericarditis, endocarditis, meningitis
112
Septic arthritis due to gonococcal infection
acute fever with pain and swelling of 1-2 joints, increased WBC. G- diplococci
113
Gonococcal disease in infants
ophthalmia neonatorum, eye infection that may cause blindness
114
Moraxella catarrhalis is associated with what diseases
otitis media and URI in pts with COPD or in the elderly
115
G- bacteria known to cause endocarditis
```
Haemophilus
Actinobacillus
Cardiobacterium
Eikenella
Kingella
```
116
Enterics
G- bacteria part of normal GI flora or cause GI disease
117
Main groups of enterics
Enterobacteriaceae, vibrionaceae, pseudomonadaceae, bacteroidaceae
118
Classifying the enterics
ability to ferment lactose, production of H2S
119
EMB agar
Methylene blue inhibits G+ bacteria, lactose fermenters become deep purple to black
120
MacConkey agar
Bile salts inhibit G+ bacteria, lactose fermentors develop pink-purple color
121
Testing for coliforms
ability to ferment lactose, green colonies on EMB agar
122
O antigen on enterics
most external component of LPS
123
K antigen on enterics
capsule that covers O antigen
124
H antigen on enterics
makes up bacterial flagella subunits
125
Diarrhea without cell invasion
bacteria bind to intestinal epithelial cells resulting in electrolyte and fluid loss; watery diarrhea without systemic problems (E. coli, V. cholera)
126
Diarrhea due to invasion of intestinal epithelial cells
toxins destroy cells, WBC and RBC in stool, fever (Enteroinvasive E. coli, Shigella, Salmonella enteriditis)
127
Diarrhea due to invasion of LN and vlood stream
abd pain, diarrhea containing RBC and WBC, fever, HA, high white count, mesenteric LN enlargement, bactermia, sepsis (S. typhi, Y. enterocolitica, C. jejuni)
128
Common nosocomial G-'s
E. coli, K. pneumoniae, P. mirabilis, Enterobacter, Serratis, P. aeruginosa
129
E. coli virulence factors
mucosal interaction (pili and epithelial cell invasion), exotoxin production (heat-labile, heat stable toxin; shiga-like toxin), Lipid A, Iron binding siderophore
130
Diseases caused by E. coli
diarrhea, UTI, meningitis, G- sepsis
131
Enterotoxigenic E. coli (ETEC)
traveler's diarrhea, LT and ST prevent reabsorption of Na and Cl and stimulate secretion of bicarb and Cl, extreme water loss
132
Enterohemorrhagic E. coli (EHEC)
shiga-like toxin prevents protein production and leads to cell death; bloody diarrhea with severe abd cramps
133
Hemolytic uremic syndrome
anemia, thrombocytopenia, renal failure due to E. coli 0157:H7
134
Enteroinvasive E. coli (EIEC)
bacteria invade epithelial cells and produce shiga-like toxin, systemic inflammatory disease with fever and diarrhea (RBC and WBC)
135
E. coli UTIs
pili allow E. coli to travel up urethra to bladder and possibly to kidneys, most common cause of UTIs; presents as dysuria, frequency, bladder fullness
136
E. coli meningitis
common cause of neonatal meningitis after Grp B Strep
137
E. coli sepsis
most common cause of G- sepsis, often occurs in debilitated hospitalized pts
138
E. coli pneumonia
fairly common cause of nosocomial pneumonia
139
Klebsiella pneumoniae
encapsulated, non-motile enteric (no H antigen), can cause sepsis and UTIs especially in hospitalized and debilitated patients (pneumonia)
140
Presentation of pneumonia due to K. pneumoniae
Hospitalized or alcoholic patient with bloody sputum, violent pneumonia that destroys lung tissue
141
Proteus mirabilis
very motile, splits urea, cross-reactive with Rickettsia; urine will be alkaline
142
Enterobacter
highly motile G- rod part of normal GI flora
143
Serratia
bright red pigment, causes UTI, wound infections, or pneumonia
144
Shigella species
dysenteriae, flexneri, boydii, sonnei
145
Shigella characteristics
non-motile, does not ferment lactose and will not produce H2S
146
Populations often affected by Shigella
preschool aged children, nursing homes
147
Where is Shigella normally found in the body?
NO WHERE! It is always a pathogen
148
Shigella action
invade intestinal epithelial cells and release Shiga toxin; often begins with a fever, abd pain, diarrhea (blood and pus)
149
Shiga toxin
B subunits bind to cell, A subunits inactivate ribosomes
150
Salmonella
Non-lactose fermenter, mobile, produces H2S
151
Vi antigen of Salmonella
polysaccharide capsule that surrounds O antigen and protects bacteria from antibody attack
152
How is salmonella most commonly acquired?
contaminated food or water with animal feces (chicken and eggs in US)
153
Disease states in human due to Salmonella
typhoid fever, carrier state, sepsis, gastroenteritis
154
Typhoid fever
invades intestinal epithelial, lymph nodes, and then seeds organ systems; facultative intracellular parasite
155
Presentation of typhoid fever
1-3 weeks after exposure, fever, HA, abd pain esp in RLQ, enlarged spleen, diarrhea, rose spots on abdomen
156
Salmonella carrier state
harbor S. typhi in gallbladders
157
What tissues does salmonella target in sepsis?
Lungs, bone, brain
158
Salmonella osteomyelitis
sickle-cell patients are most prone due to lack of effective spleen
159
Yersinia enterocolitica characteristics
G- motile rod that causes gastroenteritis
160
Which organism is Y. enterocolitica closely related to?
Y. pestis (causes bubonic plague), differs in that enterocolitica is transferred via fecal-oral route
161
Presentation of gastroenteritis due to Y. enterocolitica
fever, diarrhea, abd pain after ingestion of domestic milk or fecally contaminated water
162
Vibrio cholera
G- rod with single flagella, fecal-oral transmission
163
Cholera diarrhea
no epithelial cell attachment, release choleragen and causes rice water diarrhea
164
Vibrio parahaemolyticus
marine bacterium that causes gastroenteritis after ingestion of uncooked seafood
165
Campylobacter jejuni
One of the most common causes of diarrhea in the world, zoonotic disease, fecal-oral transmission
166
C. jejuni diarrhea presentation
fever and HA followed by abd cramps and bloody, loose diarrhea
167
H. pylori
most common cause of duodenal ulcers and chronic gastritis
168
Most of our intestinal flora is made up of what bacteria family?
bacteroidaceae, obligate anaerobic G- rod
169
B. fragilis
no endotoxin, often a common form of abscesses following intestinal laceration
170
B. melaningoenicus
produces a black pigment when grown on blood agar, involved in necrotizing anaerobic pneumonias due to GI aspiration, associated with periodontitis
171
Fusobacterium
periodontal disease and aspiration pneumonia, can cause abscesses and otitis media
172
Anaerobic G+ cocci
peptostreptococcus and peptococcus are apart of the normal flora but can be involved in abscesses and aspiration pneumonias
173
Pseudomonas aeruginosa
often colonizes very sick patients (wind, wires, wound, water) and is very resistant to antibiotics; G- obligate aerobe, green-blue color with a grape like scent
174
Common P. aeruginosa infections
pneumonia (CF and immunocompromised pts), osteomyelitis (diabetics, IV drug users, puncture wounds of foot) burn wound infections, sepsis, UTI, endocarditis, malignant external otitis, corneal infections
175
Burkholderia cepacia
oxidase positive, aerobic G- bacillus; common in CF patients
176
Actineobacter
aerobic G- found in soil and water; often causes nosocomial infections
