Title: ID BOARD REVIEW 2009
1ID BOARD REVIEW 2009
- Amanda Peppercorn, M.D.
- Assistant Professor of Medicine
- University of North Carolina at Chapel Hill
2Toxic Shock Syndrome
- Group A Strep
- Any invasive GAS infection (bacteremia, nec fasc,
gangrenous myositis flesh eating) complicated
by case definition of TSS - Exotoxin superantigens (complicated about 1/3 of
invasive GAS infections) - Associated bacteremia common
- Staph aureus toxins
- Food poisoning?staph enterotoxin
- Staph Scalded Skin?exfoliative toxin
- CA-MRSA?Panton-valentine leukocidin toxin
- TSS?TSST-1 superantigen (interact directly with
invariant region of MHC II molecule with
activation of up to 20 of all T cells with
massive cytokine storm) - Previous association with tampons
- Usually MSSA but MRSA has been reported
3Desquamation
4TSS Case Definition
- Fever Tgt38.9C (102.0F)
- Hypotension
- SBPlt90 or lt5 percentile by age for childrenlt16
years of age - orthostatic drop in DPBgt15mmHg
- orthostatic syncope/dizziness
- Rash diffuse macular erthyroderma
- Desquamation 1-2 weeks after onset of illness,
usually palms and soles - Multisystem involvement (3 or more)
- GI (vomiting, diarrhea at onset of illness)
- Muscular (severe myalgias, elevated CPK)
- Mucous Membranes (vaginal, oropharyngeal or
conjunctival hyperemia) - Renal (creatininegt2 times ULN or pyuriagt5 WBC)
- Hepatic (elevated bilirubin or transaminasesgt2
times ULN - Hematologic (plateletslt100K)
5Treatment
- Supportive, often hemodialysis, pressors, ICU
care (intractable hypotension/capillary leak) - Strep
- Emergent surgical debridement if soft tissue
primary source (pain out of proportion to exam) - Empiric Clinda (900 iv q8) imi/dori/meropenem
or pip/tazo? Taylored PCN G Clinda - IVIG
- ?immunomodulators ex TNFa inhibitors?
- MSSA clinda oxacillin/naf/cefazolin, IVIG
- MRSA clinda vancomycin, IVIG
6NECROTIZING INFECTIONS
- Necrotizing fasciitis, type 1
- Mixed infection anaerobes plus strep or GNR
- Incubation 48-96 h progression hrs days
- Marked pain, tenderness, swelling, crepitus,
foul-smelling - Necrotizing fasciitis, type 2
- Grp A strep (flesh-eating bacteria)
- Incubation 6-48 h progression a few days
- Often with toxic shock, bullae, no crepitus
- Pain out of proportion to exam
7Acute Sinusitis
- Acute Fever, facial pain, edema, erythema,
maxillary toothache - Subacute Presumed viral sinusitis with no
improvement in 7d - S. pneumoniae H. influenzae M. catarralis
- Also MRSA, aspergillus, anaerobes from mouth
flora (rare) - Amoxicillin/Clavulanate 875 mg PO Q12h x 10 d
- Levofloxacin 750 mg PO Q24h x 10 d
- Reserve antibiotics for patients failing
decongestant therapy and facial pain, purulent
discharge and/or severe illness - Treatment for full duration of therapy is
essential to prevent relapses - Supportive therapy decongestants and
antihistamines - Complications extension through bone to
brain?brain abscess - Diabetics, immunocompromised think rhinocerebral
Mucor
8Actinomycosis
- Branching filamentous anaerobic gram positive
rod, higher order bacteria appearance like a
fungus - Characteristic sulfur granules (balls of
organisms) in tissue/pathology samples - Normal part of oral flora
- Cause oropharyngeal disease (dental abscess, jaw
osteo, etc) - Also cause of uterine infection (IUDs), abdominal
abscesses - Differentiate from nocardia by anaerobic
principally and modified AFB stain (nocardia,
actino negative) - Treatment PCN, cephalosprins (keflex), clinda
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10Physiology and Resistance Mechanisms of S aureus
- S aureus is a virulent human pathogen with the
ability to elaborate a range of virulence factors
and toxins gram positive cocci in clusters - Resistance to methicillin first appeared in 1961,
attributed to inheritance of a mecA gene found on
the mobile staphylococcal cassette chromosome mec
(SCCmec) - Genetic analysis suggests that mecA has been
transferred to S aureus over 20 times, resulting
in 5 major lineages - MecA gene cassette leads to genetic alteration of
penicillin binding protein, conferring
resistance to all penicillin and cephalosporin
family of antibiotics
WTAwall teichoic acid PVLPanton-Valentine
leukocidin CHIPchemotaxis inhibitory protein.
Zetola N et al. Lancet Infect Dis.
20055275-286. Deresinski S. Clin Infect Dis.
200540562-573. Foster TJ. J Clin Invest.
20041141693-1696.
11COMPARISONCA-MRSA AND HA-MRSA
CA-MRSA HA-MRSA
Clinical spectrum Skin and soft tissue Respiratory tract, UTI, bloodstream infections
Epidemiology Clusters and outbreaks in closed populations Healthcare-associated outbreaks
Underlying condition Dermatological HAI risk factors
Age group Younger Older
Race/ethnicity
Resistance pattern Susceptible to multiple antibiotics Resistant to multiple antibiotics
Genotype sccMec IV sccMec I, II, or III
Virulence PVL present PVL absent
Diederen BMW, et al. JID 200652157-168
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13Risk Factors for CA-MRSA
- Athletes (close phyical contact)
- Military personnel
- Children
- Native Americans
- HIV
- MSM
- Prisoners
- Young sexually active
- Family members (dont forget to ask!)
- Majority of patients have no identifiable risk
factors
14Syphilis
- Early primary--painless chancre, secondary
(weeks to couple months after primary)rash
(infectious) rarely pustular, condyloma lata (MM,
moist areas) and systemic sx (fever, HA, malaise,
LAD), early latent (first year) - Late late latent, tertiary (gummas,
cardiovascular, neurosyphilisuveitis, ocular
nerve damage, dementia, paresis, tabes dorsalis,
meningitis, cranial neuropathies) - HIV primary and secondary can overlap
- Syphilis a reportable disease
- Treatment earlyIM PCN, doxy as alternative,
neurosyphilisIV PCN x 14 days - Response to treatment 4 fold decrease in
VDRL/RPR at 1 year
15Palmar involvementsecondary syphilis
16Labial Condyloma Lata, Secondary Syphilis
17CDC ISOLATION GUIDELINES
- Isolation Precautions
- Standard precautions
- Airborne precautions
- Special airborne precautions
- Droplet precautions
- Contact precautions
- Protective precautions
18STANDARD PRECAUTIONS
- Hand hygiene Before and after each patient
contact after gloves removed - The wearing of artificial fingernails or
extenders is prohibited (based on CDC guidelines) - Gloves When touching contaminated items (blood,
body fluids, secretions, excretions) - Mask, eye protection, face shield Whenever
splashes or sprays of body fluids possible - Gown Whenever splashes or sprays of body fluids
possible
19AIRBORNE PRECAUTIONS
- Isolation
- Private negative pressure room
- Direct out exhausted air
- N95 respirator
- Representative pathogens
- M. tuberculosis
- Varicella, Zoster (immunocompromised)
- Measles
20SPECIAL AIRBORNE PRECAUTIONS
- Isolation
- Airborne eye shields
- Representative pathogens
- Avian influenza
- Monkeypox
- SARS Co-V
- Smallpox
- Viral hemorrhagic fever (e.g., Ebola, Lassa)
21DROPLET PRECAUTIONS
- Isolation
- Private room
- Mask
- Representative pathogens
- Invasive N. meningitidis
- RSV
- Bordetella pertussis
- Rubella, Mumps
- Group A streptococcal pharyngitis
- Invasive H. influenzae
22CONTACT PRECAUTIONS
- Isolation
- Gloves
- Gowns
- Representative pathogens
- Clostridium difficile
- HSV
- Varicella/zoster
- VRE, MRSA
- MDR pathogens (resistant to two or more classes
of pathogens)
23BOARD REVIEW QUESTIONSINFECTION CONTROL
- 42 TB airborne, removal isolation
- 61 Varicella airborne contact
- 88 Tularemia no person-to-person
- 113 C. difficile contact enhanced
environmental cleaning (spores)
24POST-EXPOSURE PROPHYLAXIS
- Animal bite wound
- Anthrax
- Avian influenza
- Diphtheria
- Hepatitis A
- Hepatitis B
- HIV
- Human bite wound
- Influenza A
- Influenza B
- Measles
- Meningococcal infection
- Monkey bite (B virus)
- Monkeypox
- Pertussis (whooping cough)
- Rabies
- Smallpox
- Syphilis
- Tuberculosis (TB)
- Varicella (chickenpox)
- Zoster (shingles)
25POST-EXPOSURE PROPHYLAXISUSING VACCINES
- Hepatitis B lt7 days (alternative HBIG)
- Measles lt3 days (alternative Ig)
- Rabies ASAP (plus RIG) prior to symptoms
- Tetanus Post-wound (no time limit)
- Small Pox lt4 days
- Varicella lt4 days (alternative VZIG or
acyclovir) - Outbreak control Hepatitis A, pertussis,
meningococcal - May need to be provided with an immunoglobulin
preparation
26POST-EXPOSURE PROPHYLAXIS USING ANTI-INFECTIVES
- Animal bite Amoxacillin-sulbactam x 5 days
- Influenza Oseltamivir or zanimivir
- Lyme disease can offer Doxy 200 mg x 1 (with
many caveatsdefinite Ixodes, long
attachment36hrs, high endemic region20 ticks
with disease, present within 72hrs, adults and
childrengt8, non-pregnant) - Meningococcus Ciprofloxaxin 400 mg (alternative
ceftriaxone IM) - Pertussis Azithromycin x 5 days (alternative
TMP-SMX for 7-14 days) - HIV combination antiretrovirals, data supports
starting ASAP, no benefit after 72 hours (CDC 36
hours)
27 NO POST-EXPOSURE PROPHYLAXIS
- Adenovirus conjunctivitis
- Hepatitis C
- Mumps
- Parvovirus B19
- Rubella
- Severe acute respiratory distress syndrome (SARS)
28PATHOGENS ASSOCIATED WITH SKIN AND SOFT TISSUE
INFECTIONS
Cat bite Pasteurella sp (P. multocida), Franciscella tularensis
Dog bite P. multocida, Capnocytophaga canimorsus, CDC group EF-4
Human bite Eikenella corrodens, Fusobacterium, streptococci, Preotella, etc.
Rat bite Spirillum minor (systemic Streptobacillus moniliformis)
Snake bite Aeromonas hydrophila
Shark bite Vibrio carchariae
Pig bite Erysipilothrix rhusiopathiae
Animal hides Bacillus anthracis, Franciscella tularensis
29PATHOGENS ASSOCIATED WITH SKIN AND SOFT TISSUE
INFECTIONS
Injection drug use S. aureus, Clostridium sp., E. corrodens, Grp A strep
Salt water injury Vibrio Vulnificus
Fresh water injury Aeromonas hydrophila
Fish tank exposure Mycobacterium marinum
Fishmonger Erysipilothrix rhusiopathiae, Streptococcus iniae
Medicinal leeches A. hydrophila, Aeromonas sobria, Vibrio fluvialis
Hot tubs Pseudomonas aeruginosa
Plant/soil exposure Sporotrichosis
Soil contamination Nocardia, Clostridium sp., Serratia
30TREATMENT OF MRSA ORAL THERAPY
- Oral regimens (use only after susceptibility
testing) - Linezolid (expensive)
- Clindamycin (use only if erythromycin susceptible
or D test performed to confirm susceptibility) - Trimethoprim-sulfamethoxazole
- Minocycline
- Monitoring
- Daptomycin CPK each week stop if CPK gt5x ULN
(symptomatic) or gt10x ULN (asymptomatic) or gt1000
U/L - Linezolid CBC with platelets each week do not
treat gt28 days
31BOARD REVIEW QUESTIONSSKIN
- 68 Osteo in drug user
- 71 Human bite
- 83 Cat bite
- 85 IDU joint infection
- 94 SA infection
- 107 - NTM
32CAP PATHOGENS
Outpatient Inpatient (non-ICU) Inpatient ICU
S. pneumoniae M. pneumoniae H. influenzae C. pneumoniae Respiratory viruses S. pneumoniae M. pneumoniae C. pneumoniae H. Influenzae Legionella spp. Aspiration Respiratory viruses S. pneumoniae S. aureus Legionella spp. Gram-negative bacilli H. influenzae
Influenza A and B, adenovirus, RSV,
parainfluenza
Mandell LA, et al. Clin Infect Dis 200744(suppl
2)27-72
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34CAP THERAPY OUTPATIENTS
- Previously healthy and no risk factor for DR-SPn
- No recent antibiotics Macrolide (I),
doxycycline (III) - Recent antibiotics FQ, advanced macrolide
high-dose amoxicillin, advanced macrolide
high-dose amoxicillin/clav - Comorbidities Chronic heart, lung, liver, or
renal disease - No recent antibiotics Advanced macrolide, FQ
- Recent antibiotics FQ (I), ?-lactam macrolide
(I), ?-lactam doxycycline (II) ?-lactam high
dose amoxicillin or amox-clav - Regions with gt25 high level macrolide resistant
SPn use alternative agent
35CAP THERAPY INPATIENTS, NON-ICU
- Non-ICU
- FQ (I)
- ?-lactam macrolide (I)
- ?-lactam cefotaxime, ceftriaxone, ampicillin
- ICU
- ?-lactam FQ (I)
- ?-lactam cefotaxime, ceftriaxone,
ampicillin-sulbactam - ?-lactam advanced macrolide (II)
- ?-lactam cefotaxime, ceftriaxone,
ampicillin-sulbactam - Advanced macrolide azithromycin or
clarithromycin
36Pneumococcus
- 50 resistance at UNC to all macrolides
(mechanism alteration of ribosome binding site) - Vanc susceptible--universal
- Resistance an issue for
- Beta-lactams (penicillins, cephalosporins, and
carbapenems) 20 PCN R, 5 Cephalosporin R - Macrolides (erythromycin, azithromycin,
clarithromycin and lincosamines (clindamycin) - Tetracyclines and folate inhibitors
(trimethoprim-sulfamethoxazole TMP-SMX) - Fluoroquinolones (ciprofloxacin, levofloxacin,
gemifloxacin, moxifloxacin) - Meningitis vanc (to cover R pneumococcus), ctx
(better CNS penetration, good for meningococcus
and pneumoncoccus), steroids (particularly for
pneumococcus, to prevent hearing loss and other
long term complications) although steroids may
decrease CNS penetration of vancomycin
ampicillin for young and old and
immunocompromised (to cover listeria) - No steroids in places with HIV prevalence and
presumed meningitis
37BROAD SPECTRUM ANTIBIOTICS
- Carbapenems Imipenem, meropenem (not ertapenem)
- Coverage GPC, GNRs, P. aeruginosa, anaerobes
- Holes MRSA, Listeria, Legionella
- Piperacillin-tazobactamn (not ticar/clav or
amp/sulbactam) - Coverage GPC, GNRs, P. aeruginosa, anaerobes,
enterococci - Holes MRSA, Listeria, Legionella
- Tigecycline
- Coverage GPC (including MRSA, VRE), GNRs
(including ESBL producers and Acinetobacter),
anaerobes - Holes Pseudomonas aeruginosa, Proteus spp.
38BROAD SPECTRUM ANTIBIOTICS USES
- Sepsis of unknown etiology (GPC, GNR)
- Neutropenic fever (GNR, PA, SA)
- Severe intra-abdominal infections (GNR,
Enterococcus, anaerobes) - Gangrenous soft tissue infections (diabetic)
(GNR, PA, SA) - Known resistant pathogens (ESBL, Acinetobacter,
Burkholderia, Pseudomonas)
39Endocarditis
- Updated Duke Criteria 2-1/3-5 (major/minor
criteria) - Major sustained bacteremia by organism known to
cause endocarditis (SA, S viridans, enterococcus,
HACEK, CNS with pv), endocardial involvement seen
by echocardiogram (vegetation, abscess OR new
valvular regurgitation) - Minor predisposing condition (PPM/vascath, HD,
IVDA), fever, vascular signs (septic emboli,
janeway lesions, mycotic aneurysms), immune
complex phenomena (osler nodes, roth spots,
glomerulonephritis) blood culture not meeting
standard criteria - Categories native valve (bicuspid,
calcification, prior endocarditis, any valvular
disease), prosthetic valve (high mortality, need
rifampin/gent, often requires surgery), IDU (can
use shorter course of treatment with right sided) - Culture negative q fever, brucella, bartonella,
legionella, chlamydia, HACEK, nutritionally
deficient strep - Indications for valve surgery persistent
bacteremia, refractory CHF, myocardial
abscess/purulent pericarditis, difficult
organisms (PsA, yeast, MRSA), recurrent septic
embolic complications, large vegetation
40Tuberculosis
- PPD treatment
- gt5mm HIV, immunosuppressed (TNF inhibitor,
prednisone 15 mg/d x 1 month), known close
contact - gt10mm all other high risk populations
(prisoners, healthcare worker, RF, homeless,
immigrants, DM, malignancy, hx gastrectomy,
malnutrition, etoh, long-term care) - gt15mm everyone else
- Treatment rule out active disease by CXR and
symptom screening - TB considerations BCG (no change in
interpretation, esp if gt5 years ago), prophylaxis
and treatment in setting of MDR - Primary disease?dissemination?control or active
disease (lungs, LNs, pleurisy, CNStuberculomas,
basilar meningitis, GI, GUuterine, kidneys,
bonePotts disease, neck LNScrofula), HIV,
miliary
41AHA Guidelines for Endocarditis Prophylaxis 2007
Update
- IE is much more likely to result from frequent
exposure to random bacteremias associated with
daily activities (eg, tooth brushing) than from
bacteremia caused by a dental, gastrointestinal,
or genitourinary procedure. - Prophylaxis may prevent an exceedingly small
number of cases of IE, if any, in individuals who
undergo these procedures. - The risk of antibiotic-associated adverse events
exceeds the benefit, if any, from prophylactic
antibiotic therapy. - Maintenance of optimal oral health and hygiene
may reduce the incidence of bacteremia from daily
activities and is therefore more important than
prophylactic antibiotics for a dental procedure
to reduce the risk of IE.
42Updates
- Patients with the following cardiac conditions
were considered to meet this criterion - Prosthetic heart valves, including bioprosthetic
and homograft valves - Prosthetic material used for cardiac valve repair
- A prior history of IE
- Unrepaired cyanotic congenital heart disease,
including palliative shunts and conduits. - Completely repaired congenital heart defects with
prosthetic material or device, whether placed by
surgery or by catheter intervention, during the
first six months after the procedure. - Repaired congenital heart disease with residual
defects at the site or adjacent to the site of
the prosthetic device. - Cardiac "valvulopathy" in a transplanted heart.
Valvulopathy is defined as documentation of
substantial leaflet pathology and regurgitation
43- No longer indicated Common valvular lesions for
which antimicrobial prophylaxis is no longer
recommended include bicuspid aortic valve,
acquired aortic or mitral valve disease
(including mitral valve prolapse with
regurgitation and those who have undergone prior
valve repair), and hypertrophic cardiomyopathy
with latent or resting obstruction - Procedures that may result in transient
bacteremia and are recommended for prophylaxis - All dental procedures that involve manipulation
of either gingival tissue or the periapical
region of teeth or perforation of the oral
mucosa. - Procedures of the respiratory tract that involve
incision or biopsy of the respiratory mucosa - Procedures in patients with ongoing GI or GU
tract infection - Procedures on infected skin, skin structure, or
musculoskeletal tissue - Surgery to place prosthetic heart valves or
prosthetic intravascular or intracardiac
materials.
44Botulism gram positive anaerobic rod, toxin
releasing, spore producing, with bioterrorism
potential
- The modern syndrome of botulism occurs in five
forms, differentiated by the mode of acquisition
2 - Food-borne botulism ingestion of food
contaminated by preformed botulinum toxin - Infant botulism the ingestion of clostridial
spores that then colonize the host's
gastrointestinal (GI) tract and release toxin
produced in vivo - Wound botulism infection of a wound by
Clostridium botulinum with subsequent in vivo
production of neurotoxin - Adult enteric infectious botulism or adult
infectious botulism of unknown source similar
to infant botulism in that toxin is produced in
vivo in the GI tract of an infected adult host. - Inhalational botulism the form that would occur
if aerosolized toxin was released in an act of
bioterrorism. - Cranial neuropathies, symmetric descending
paralysis, no fever, no sensory loss - The differential diagnosis for food-borne, wound,
and adult enteric botulism includes myasthenia
gravis, Lambert-Eaton myasthenic syndrome (LEMS),
tick paralysis, Guillain-Barré syndrome,
poliomyelitis, stroke, and heavy metal
intoxication. Less likely diagnoses include
tetrodotoxin and shellfish poisoning and
antimicrobial-associated paralysis - Dx clinical syndrome, EMG studies, reportable
disease, stool studies, serum toxin assays - Treatment supportive (most need intubation),
antitoxin (equine trivalent anti-toxin for gt1
year of age, botulism immunoglobulin for
infants), PCN G for wound botulism
45Giardia
- Flagellated protozoan parasite
- Cysts (live in environment), trophozoites
(reproductive form)--pear-shaped, binucleate,
multi flagellated organisms,measures 9-15 µm
long, 5-15 µm wide, and 2-4 µm thick - Worldwide, food-borne, water-borne,
person-person, especially children in developing
countries - Other common GI parasite is Cryptosporidium
parvumGiardia and Crypto problem in normal hosts
and important in HIV and immunocompromised (less
common protozoan is E. histolytica) - Dx stool O and P (cyst and troph), stool
antigenic testing (ELISA)
46Giardia trophozoite
47Giardiasis
- 60 asymptomatic
- Diarrhea that is sudden in onset and may be
initially watery 90 percent - Malaise 85 percent
- Foul-smelling and fatty stools (steatorrhea) 70
percent - Abdominal cramps and bloating 70 percent
- Flatulence 75 percent
- Nausea 70 percent
- Weight loss 65 percent
- Vomiting 30 percent
- Fever 10 percent
- Manifestations often wax and wane over many
months - Malabsorptionlactase (causes lactose
intolerance), vitamin A, B12, folate, etc
48Miscellaneous
- Remember syphilis!!
- African tick feverR. africae (look for eschars,
early fever/myalgias)Amblyoma tick, doxycycline - Other tick borne diseasesR. rickettsia (dog
tick, RMSF), Erlichia (deertickIxodes or lone
star tick), Borrelia (Lyme, Ixodes), Babesia
(protozoa looks like malaria, only in NE, fatal
in asplenic pts, Ixodes) - Anthraxcutaneous (Edema toxin), eschar also
inhalational (hemorrhagic, widened mediastinum)
and GI (ingestion of infected animal) - Candidemia
- Smallpox versus Chickenpoxdegree of fever and
early timing of systemic symptoms, stage of
lesions - Drugs
- daptomycin contraindicated for MRSA pneumonia,
follow CPK - Linezolidthrombocytopenia, bone marrow
suppression, serotonin syndrome - HIV medsabacavir (fatal hypersensitivity
syndrome, HLA B5701), protease inhibitorselevated
lipids, DM, nucleoside RTIsmitochondrial
toxicity (lipodystrophy, visceral adiposity,
myalgias, neuropathy), nevirapine (fatal liver
disease esp in women with high CD4)
49Thank You