Lecture 5: Bacterial Infections Part 2 Flashcards
1
Q
What are the 3 main G+ anaerobes?
A
Actinomyces
Peptostreptococcus
Propionibacterium
Great PLUS PAPA
2
Q
How do G+ anaerobes generally present?
A
Abscess formation with tissue necrosis.
Suppurative/purulent
FOUL ODOR of pus or infected tissue.
Site of infection is near somewhere anaerobes like.
Often polymicrobial!
Note:
G- anaerobes present similarly.
3
Q
Which G+ anaerobe is most likely to be found on a prosthetic?
A
Propionibacterium
4
Q
Which G+ anaerobe is most likely to cause aspiration pneumonia?
A
Actinomyces
5
Q
Which G+ anaerobe is most likely to cause an oral infection?
A
Peptostreptococcus
6
Q
How does aspiration pneumonia present on CXR if caused by a G+ anaerobe?
A
Infiltrates w/ or w/o cavitation
Lucency within an infiltrate suggests necrotizing tissue.
Air fluid levels within a circumscribed infiltrate = lung abscess
7
Q
How do I check for an intra-abdominal abscess?
A
Abd/Pelvic CT
8
Q
How do we diagnose a G+ anaerobe infection?
A
Clinical suspicion + Gram stain + C&S
Note:
C&S for an anaerobe can take 1+ week.
9
Q
What is the tx protocol for a G+ anaerobe infection dependent on?
A
Site of infection.
10
Q
What is the tx protocol for an oral/throat/neck G+ anaerobe?
A
Clindamycin
Augmentin
Unasyn (amp/sul)
11
Q
What is the tx protocol for a GI/pelvic abscess dt G+ anaerobe?
A
Oral: Moxi
Mod/severe :
Ertapenem or Rocephin + metronidazole (covers B. fragilis and G-) all IV!!
Severe:
Imipenem (IV)
12
Q
What is the tx protocol for a lung abscess dt G+ anaerobe?
A
Beta-lactam + inhibitor:
Unasyn OR imipenem OR meropenem OR clindamycin
13
Q
What is the tx protocol for aspiration pneumonia?
A
OP: augmentin or doxy
IP: Unasyn
OR
Metro + amoxicillin or pen G
14
Q
What is the prophylaxis tx for dental procedures?
A
PCN if joint implant.
Amoxicillin works for both joint implant or endocarditis prophylaxis.
15
Q
What is the prophylaxis for colorectal surgery?
A
Metronidazole + 2nd/3rd gen cephalosporin OR cipro
Carbapenems
16
Q
What are the 5 disease causing clostridiums?
A
C. perfringens
C. sepicum
C. tetani
C. botulinum
C. diff
17
Q
What clostridiums cause gas gangrene?
A
C. perfringens
C. sepicum
18
Q
What is the most common species of clostridium?
A
C. perfringens
19
Q
Where is C. perfringens most commonly found?
A
soil
20
Q
What are the S/S of a clostridium SSTI?
A
Pain, edema, erythema, TISSUE CREPITUS, foul smelling.
21
Q
How is a clostridial SSTI diagnosed?
A
Clinical suspicion
Gram stain
Culture
Note:
Clostridia produce extremely fast, can culture in ~6 hours.
Need to culture bc strep, staph, and enterococci can cause similar symptoms.
22
Q
What is the tx protocol for a clostridial SSTI?
A
Drainage and debridement
Pip/tazo + clindamycin (covers strep and clostridia)
Can change to PCN + clinda if no strep.
Hyperbaric tx
Note:
Pip/tazo also covers pseudomonas
23
Q
What is the pathophys of C. perfringens gastroenteritis?
A
Enterotoxin production from C. perfringens.
24
Q
How does C. perfringens gastroenteritis present?
A
Mild.
Watery diarrhea.
Emesis and fever are rare.
25
What is the tx protocol for C. perfringens gastroenteritis?
None.
Self-limiting
26
How does tetanus occur?
Spores from C. tetani enter body from wound/burn/IV drug use.
Attaches to peripheral nerve ending, cause muscle stimulation.
Leads to tonic spasticity and muscle rigidity.
CANNOT BE NEUTRALIZED ONCE BOUND
27
What is the incubation period of tetanus?
5-30 days.
28
How does tetanus commonly present?
Jaw stiffness
Difficulty swallowing
Stiff neck, arms, and/or legs
HA
Tonic muscle spasms
Trismus
Resp failure dt laryngeal/diaphragmatic spasms.
29
How is tetanus diagnosed?
Clinical suspicion
Cultures (not sensitive?)
30
What is the tx protocol for tetanus?
Supportive care
Wound debridement
Tetanus immune globulin (HTIG) IM within 24 hrs.
Full series of tetanus vaccine
PCN or metronidazole
Vaccination is best.
31
What are the common sources of C. botulinum?
Home-canned foods (MC)
Commercial foods
Direct injection/wound
32
What is the only non-natural form of botulinum infection?
Inhalation of toxin.
33
How many subtypes of C. botulinum are there?
8
34
How does botulism present in regards to the nervous system?
Dry mouth
Slurred speech
Dysphagia
Blurred vision
Drooping eyelids
Eventually respiratory failure due to diaphragmatic paralysis
35
How does botulism present initially before neurological symptoms?
N/V/abd cramps
18-36 hours post ingestion.
36
How is botulism different from tetanus if they both cause respiratory failure?
Botulism paralyzes the diaphragm.
Tetanus overstimulates the diaphragm to where it becomes stiff.
37
How is botulism diagnosed?
Cultures:
Stool for ingested
Wound for injection
38
Who can perform a toxin assay and what is it?
Identifies specific toxin made by C. botulinum.
Only performed at special labs, such as the health department or CDC.
39
What is the tx protocol for C. Botulinum?
Hospitalization + supportive care.
Requires NG tube and/or ET tube
Antitoxin through the CDC.
Wound botulism requires PCN G or metronidazole.
40
What is C. Diff colitis also known as?
Pseudomembranous colitis
41
What is the pathophys of C. Diff colitis?
Overgrowth of organism in the colon due to excessive ABX growth.
42
How does C. Diff antibiotic associated colitis/pseudomembranous colitis present?
Diarrhea, frequent stool, either watery or bloody.
Abd cramping, tenderness, and bloating.
N/V is RARE.
Presents 5-10 days post abx initiation, but can take up to 2 months.
43
How is pseudomembranous colitis diagnosed?
Stool sample for toxin
Fecal leukocytes
Sigmoidoscopy if suspicious w/ - culture
Other imaging to check for ileus or distended colon
44
What is the tx protocol for mild-moderate pseudomembranous colitis?
Fidaxomicin or Vanco (oral)
45
What is the tx protocol for severe pseudomembranous colitis?
Vanco (oral or enema in rare cases)
Fidaxomicin + Metronidazole
46
What is the tx protocol for recurrent or refractory pseudomembranous colitis?
Recurrent will be same as mild-moderate.
Refractory will be a fecal transplant.
47
What are the 4 G- anaerobes?
Bacteroides
Fusobacterium
Porphyromonas
Prevotella
BFPP
48
What kind of infection is B. fragilis most commonly known for?
Intra-abdominal infections (most virulent)
49
Where are prevotella and fusobacterium found?
Normal gut and bowel flora.
50
How do G- anaerobes typically present?
Abscess formation with tissue necrosis
Suppurative/Purulent
Foul odor
Site of infection is near a common anaerobe site
Polymicrobial
AKA identical to a G+ anaerobe.
51
How is a G- anaerobe diagnosed?
Same as G+ anaerobe. Culture the abscess.
Gram stain
C&S may take 1 week.
52
What do anaerobic infections generally all culminate in?
Bacteremia, but usually not sepsis.
53
What is the tx protocol for a G- anaerobe infection?
Drainage and debridement.
ABX depending on site of infection.
54
What is the recommended abx for an oral/throat/neck G- anaerobe infection?
Clinda or metro
55
What is the recommended abx for a GI/pelvic abscess due to G- anaerobe?
Zosyn
Carbapenems
Metro + cefepime
56
What is the MC for bacterial vaginosis?
Gardnerella
57
How does bacterial vaginosis usually present?
Often asymptomatic.
Signs incude:
Thin, off-white to grayish vaginal discharge
Fishy smell from vagina
Elevated pH of vaginal discharge
Clue cells on microscopy
Positive whiff test
58
What is a whiff test?
Vaginal discharge + KOH.
KOH will alkalize amines made by anaerobes, which will result in a fishy odor.
59
What are clue cells?
Vaginal cells with a bunch of bacteria attached to them.
60
What is the tx protocol for bacterial vaginosis?
Metro (oral or vaginal)
Clinda (oral or vaginal)
Tinidazole (oral)
61
What are the 3 atypical causes of pneumonia?
Mycoplasma
Legionella
Chlamydia
62
What are significant characteristics of Mycoplasma?
Small bacteria w/o a cell wall.
Human pathogens.
M. pneumo is most associated with acute infection (pneumonia)
63
What is the pathogenesis of mycoplasma?
Filamentous organism that attaches to epithelial membranes, esp. in the respiratory tract.
Activates immune response by injuring epithelium.
64
What is the epidemiology of mycoplasma?
Respiratory droplet transmission with an incubation period of 2-3 weeks.
MC during fall, summer, young adults.
65
How does M. pneumo typically present?
Gradual onset
Mild form
Scant sputum production
Often has pharyngitis or AOM.
Bullous myringitis
Often called walking pneumonia
66
How is M. pneumo diagnosed?
Chest auscultation will be clear
Patchy infiltrates on CXR, negative for consolidation.
Usually, its just a clinical diagnosis or an NP swab.
67
What is the tx protocol for M. pneumo?
Azithromycin is the empiric abx of choice.
68
What are the characteristics of Chlamydia?
Obligate intracellular bacteria without a cell wall.
3 pathogens are:
trachomatis
psittaci
pneumo
69
What is the second MCC of atypical pneumonia?
Chlamydia pneumo
70
What is the tx protocol for C. pneumo?
Same as M. pneumo in terms of presentation and tx.
Azithromycin.
71
How does psittacosis present?
Atypical pneumonia that is sicker than other.
72
How is psittacosis transmitted?
Bird contact with 7-15 day incubation period.
73
What is the tx protocol for Psittacosis?
Tetracycline
Erythromycin
74
What are the S/S of C. trachomatis?
Female: cervicitis, urethritis, PID
Male: Urethritis, epididymitis, prostatitis
Both: conjuctivitis, lymphogranuloma venereum
75
How does Chlamydia present?
Asymptomatic
Signs:
Females will have mucopurulent discharge, red, inflamed, friable cervix, and PID + chandelier's sign.
Males will have mucoid/watery urethral discharge, dysuria, and epididymitis
76
How is chlamydia diagnosed?
Culture.
Gram stain is useless.
Often screened for as well.
77
What DDx should be considered with possible chlamydia?
Dysuria
Bacterial vaginosis
Trichomonas
Candidiasis
Gonorrhea
HSV
78
What is the tx protocol for urogenital chlamydia?
Zithromax 1g.
Rocephin shot in case for gonorrhea
79
What complications can occur due to chlamydia?
PROM (premature rupture of membranes) in pregnancy.
Infertility due to PID
Newborn transmission
Perihepatitis (Fitz Hugh-Curtis syndrome)
80
What 3 bacteria are spirochetes?
Treponema pallidum (Syphilis)
Borrelia (Lyme)
Leptospira (Leptospirosis)
81
What are the stages of syphilis?
Primary
Secondary
Tertiary
Neurosyphilis (Late)
Latent
82
What stages of syphilis are contagious and non-contagious?
Primary, secondary, and latent are contagious.
Tertiary and later is not.
83
What stage of syphilis is generally asymptomatic?
Latent syphilis, aka within 1st yr of primary infection.
84
How does primary syphilis present?
Chancres
Nontender regional LAN
Spontaneous healing
3-4 weeks post contact
85
How is primary syphilis diagnosed?
Culture of ulcer via dark field microscopy to look for spirochetes.
Serologic tests: (FIRST LINE)
RPR (rapid plasma reagin) & VDRL (venereal disease research lab test)
These are generally used for secondary stage diagnosis and are NON ANTIBODY
Antibody:
TPPA (treponema pallidum particle agglutination test)
FTA-ABS (Fluorescent treponemal antibody absorption)
Often used to confirm diagnosis.
86
How is primary syphilis treated?
1 shot of benzathine pencillin G (Bicillin-LA)
87
What is the main difference between primary and secondary syphilis?
Systemic symptoms due to dissemination of bacteria.
88
How does secondary syphilis present?
Generalized maculopapular rash
Mucous membrane patches and ulcers
Condyloma lata
Meningitis
Iritis
Hepatitis
Arthritis
Fever
Generalized LAN
89
What is the tx protocol for secondary syphilis?
Same as primary.
1 shot Bicillin
90
What is the hallmark sign of tertiary/late syphilis?
GUMMAS
Infiltrative tumors in the skin, bones, and internal organs (liver)
91
When is neurosyphilis most common?
Late syphilis. but it can occur at ANY STAGE
92
What is the disease course of neurosyphilis?
CSF infection with no symptoms.
Meningeal symptoms occur as meningovascular syphilis occurs.
Tabes dorsalis (chronic progressive degen of posterior columns of spinal cord)
Inability to walk in the dark, inability to control bladder, paresthesias, and a wide-based gait.
General paresis as cerebral cortex gets infected.
93
How is neurosyphilis diagnosed?
Same + LP
94
How is neurosyphilis treated?
Still pcn
95
What are the main risk factors for neurosyphilis?
HIV
Non-HIV: male or 45+ yo
96
What is the tx protocol in any stage of syphilis?
Benzathine PCN
97
What bacteria causes lyme disease?
Borrelia burgdorferi
98
What is the mode of transmission for lyme disease?
Ixodes tick (deer tick)
99
What are some characteristics of lyme disease?
Most common tick-borne illness in the US
Most common in spring and summer
Most common in NE and North central US
100
How does the 1st stage of lyme disease present?
Early, localized infection with a target rash in 80-90% of pts within a week.
FLS
Even without tx, it can resolve in 3-4 weeks.
101
How does the 2nd stage of lyme disease present?
Bacteremia
Secondary skin lesions and rash
Worsening of FLS
Rare cardiac involvement (4-10%), such as arrhythmias or heart block.
Neurologic manifestations (10-15%), such as aseptic meningitis, facial palsy.
102
How does the 3rd stage of lyme disease present?
Months to years post infection
MSK pain (60%)
Neurologic
Skin
Generally fine if untreated.
103
What is the criteria of a lyme disease diagnosis?
Person exposed to tick bite must have:
Erythema migrans OR one late manifestation
+
Lab confirmation
104
What are the lab tests for lyme disease?
ELISA test first-line.
Western blot confirmation.
105
What is the tx protocol for lyme disease?
Doxycycline.
Pregnant women can use amoxicillin.
Doxy is ok in children if under 21 days.
106
How is leptospirosis transmitted?
Leptospira in the urine of infected rats.
107
How does leptospirosis present?
Minor to fatal liver/kidney disease
108
How is leptospirosis diagnosed?
Serologic testing
109
What is the tx protocol for leptospirosis?
Doxycycline
110
How is rocky mountain spotted fever transmitted?
Ticks carrying rickettsia rickettsii
Dermacentor ticks (wood and dog ticks)
111
Where is rocky mountain spotted fever most commonly found?
NC
TN
OK
AK
MO
112
What is the most fatal rickettsia disease?
Rocky mountain spotted fever, with a 73% mortality if untreated.
113
How does rocky mountain spotted fever present?
2-14 days post bite.
Starts with mild FLS, but progresses to a characteristic rash.
Rash starts as faint macules, goes to papules, then to petechiae.
Always begins on wrists and ankles.
114
How is rocky mountain spotted fever diagnosed?
Clinical + serologic testing
115
What is the tx protocol for RMSF?
DOXY
Cannot use amoxicillin!!!!!!!!!!
116
How are all rickettsial diseases treated?
DOXY!!!!!!
117
What is the clinical definition of diarrhea?
Increased stool frequency (>3 BMs/day)
OR
Liquidity of feces
118
What time frame is acute diarrhea?
<= 14 days
119
What time frame is persistent diarrhea?
> 14 days, <30 days
120
What time frame is chronic diarrhea?
>30 days
121
What DDx are common for acute diarrhea?
Infectious etiology
Medications
Acute exacerbations of a chronic disease
122
What DDx are common for chronic diarrhea?
Osmotic
Secretory
Inflammatory
Meds
Malabsorption syndromes
Motility disorders
Chronic infections
Factitious
123
What are the bacterial etiologies possible for diarrhea?
S. aureus
B. cereus
E. coli (hemorrhagic or toxigenic)
C. diff
C. jejuni
Salmonella
Shigella
Vibrio
Listeria
124
What are the viral etiologies possible for diarrhea?
Norovirus
Rotavirus
Hep A
Adenovirus
CMV
125
What are the protozoal etiologies for diarrhea?
Giardia lamblia
Entamoeba histolytica
Cryptosporidium
Cyclospora
Isospora
126
What is the main clue in terms of diarrhea diagnosis?
Bloody = inflammatory
Non-bloody = non-inflammatory
127
What significant lab finding will be present in inflammatory diarrhea?
Positive fecal leukocytes
128
What does bloody stool suggest about etiology?
Most likely bacterial, as the only other causes are CMV or entamoeba histolytica.
129
What are the bacterial etiologies for inflammatory diarrhea?
C. jejuni
Salmonella
Shigella
E. coli (hemorrhagic)
C. diff
CSESC
130
What are the bacterial etiologies for non-inflammatory diarrhea?
B. cereus
S. aureus
E. coli (Toxigenic)
V. cholera
BEVS
131
What are the common associated signs with inflammatory diarrhea?
Fever and abdominal tenderness.
132
What generally causes N/V in infectious diarrhea?
S. aureus
B. cereus
Norovirus
Rotavirus
Note:
All non-inflammatory etiologies
133
What kind of diarrhea usually causes volume depletion?
V. cholera causing non-inflammatory diarrhea.
134
What kind of etiologies do HIV pts have if they have diarrhea?
CMV
Cryptosporidium
Isospora
135
What is the second clue regarding diarrhea etiology?
Exposure history, such as what they ate, traveled to, abx use...
136
What is the third clue regarding diarrhea etiology?
Incubation period.
137
Which bacteria have the fastest incubation generally?
S. aureus
B. cereus
138
What bacteria generally take about 1 day to incubate for diarrhea?
E. coli (both kinds)
Vibrio
139
How long do mucosal invasion bacteria take to incubate?
1-3 days.
C. jejuni
Shigella
Salmonella
140
How long do viruses generally take to incubate to cause diarrhea?
1-2 days
141
How long do protozoans generally take to incubate to cause diarrhea?
1-2 weeks
142
What would prompt us to do a diagnostic workup for diarrhea?
Bloody/mucus stool
Severe dehydration
>2 weeks duration
143
What is the workup protocol for infectious diarrhea?
Fecal leukocyte
Stool culture (can check salmonella, shigella, and jejuni)
Stool for O & P (Protozoans)
Stool for C. diff
Viruses
Sample stool culture: Stool for SSYC, O&P, WBCs, C. diff, and viruses.
SSYC = salmonella, shigella, yersinia, campylobacter
Yersinia is a type of ecoli
144
How is diarrhea treated?
Fluids
Antidiarrheals (Loperamide, diphenoxylate, bismuth/pepto)
ABX if inflammatory or extended non-inflammatory.
145
What is the empiric abx tx for diarrhea?
Cipro, levofloxacin, etc...
Need cultures still.
146
How is the tx protocol for diarrhea modified for pregnant women and children?
Pregnant women, children, and inflammatory diarrhea should NOT TAKE PEPTO/BISMUTH.
Children should not take meds generally for diarrhea. Probiotics and fluids are preferred.
