Infectious Disease Flashcards
Skin or Soft tissue infection
What are two ways osteomyelitis can be spread?
Hematogenous and contiguous spread
Viruses
What does cytopathology show in CMV?
Owl Eyes
STD
(T/F) Viral shedding occurs in HSV even in the absence of lesions
True
Bacteria
What are gram negative coccobacilli (2)?
H influenza and Bordetella (Pertussis)
Antibacterial
What are two fifth generation cephalosporins and what are each good at covering?
Ceftaroline - MRSA
Ceftolozone - Pseudomonas
How does reactivated TB typically present?
Subacute illness over weeks/months with fever/night sweats/weight loss/cough
What is metronidazole used to cover?
Anaerobic infections below the diaphragm
What test should be ordered before starting Dapsone?
G6PD deficiency
What are six antibiotics that cover MRSA?
Vancomycin
Daptomycin
Linezolid
Clindamycin - community MRSA
Fluoroquinolones
TMP-SMX
Name three big shapes of gram positive bacteria?
- Cocci - Staph/Strep
- Branching filaments - Actinomyces/Nocardia
- Bacilli (rod)- Listeria/Bacillus/Clostridium
What are five diseases that cause genital ulcers?
Which are painful?
- HSV - painful
- Syphilis - Painless
- Haemophilus ducreyi (chancroid)- Painful
- Lymphogranuloma venereum - painless
- Granuloma inguinale - painless
Painful ones start with H for Hurt
What are gram negative dipplococci?
Neisseria meningitidis
Neisseria gonorrhoeae
What generations of cephalosporins cover anaerobes?
2nd and fifth generation
Treatment for ebola?
Supportive care
Treatment for Smallpox?
Supportive care
Define multi-drug resistant TB?
TB that is resistant to INH and/or rifampin
What are three side effects of Vancomycin treatment?
- Red-man syndrome
- Ototoxicity
- Nephrotoxicity
What virus causes temporal lobe encephalitis and what are the EEG findings?
HSV encephalitis.
You will see 2-3 mm HZ highly characteristic slow wave complexes on EEG
What are the major symptoms of a brain abscess? What is the size cutoff for brain abscesses that require drainage?
Severe headache. Other symptoms such as neck stiffness, fever may not always be present.
Abscess greater than 2.5 cm should be excised or drained.
When should necrotizing fasciitis be suspected in patients?
If a patient has skin inflammation with hemodynamic instability, rapid progression, pain out of proportion to exam, physical exam with necrosis, bullae, crepitus, it is important to consider a deeper tissue infection like necrotizing fasciitis and to obtain urgent surgical consultation.
When should necrotizing fasciitis be suspected in patients?
If a patient has skin inflammation with hemodynamic instability, rapid progression, pain out of proportion to exam, physical exam with necrosis, bullae, crepitus, it is important to consider a deeper tissue infection like necrotizing fasciitis and to obtain urgent surgical consultation.
Urinary Tract Inections
What three groups of patients should receive treatment for asymptomatic bacteruria?
- Pregnant patients
- Patients undergoing invasive urinary urological procedures
- Renal transplant patients/immunocompromised patients
Gastrointestinal Infections
What kind of foods is Bacillus cereus associated with?
Starchy/fried foods
What are three types of gram positive bacilli?
Listeria
Clostridium
Bacillus
What is a unique side effect of imipenem?
Decreases seizure threshold
When should vancomycin not be used?
When MIC is greater than 2
What are the gram negative bacilli?
SSEKP
Shigella
Salmonella
E coli
Pseudomonas
Klebsiella
What are some causes of encephalitis and how does it present?
Causes - HSV, Arbovirus (West Nile and St. Louis), Lyme disease
Symptoms - Confusion/AMS are most prominent findings. Fever/headache/focal neurological deficits are other findings
What is chemoprophylaxis for Neisseria Meningitidis and who should receive treatment?
Rifampin/Ciprofloxacin/Rocephin
Give to household contacts, salivary contacts, or healthcare providers who have had direct contact with an infected patient’s oral and respiratory secretions without a mask
T/F - All patients with tick bite should be treated with prophylactic and empiric antibiotics
False
What is the PPD cutoff in HIV patients and what are next steps if cutoff is met?
PPD > 5 mm. If PPD positive, check for active infection and if active infection is ruled out, then treat as latent TB (INH for 9 months or rifampin for 4 months)
What are two branching filament gram positive organisms and how do you treat each?
(Aerobic) Norcadia - TMP-SMX
SNAP
(Anaerobic) Actinomyces - Penicillins
What are four groups of beta lactam antibiotics?
- Penicillins
- Cephalosporins
- Monobactams
- Carbapenems
What are gram negative curved rods?
H pylori
Vibrio
Camplyobacter Jejuni
What types of bacteria can cause infections in DM patients?
Polymicrobial infections
Anaerobic infections
Gram positive and gram negative bacteria
Endocarditis
How many blood cultures should be obtained in patients with suspected endocarditis?
Three sets of blood cultures taken at least one hour apart before antibiotics
Anti-bacterial agents
What kind of organisms is vancomycin used to treat?
Gram positive organisms
MRSA
What is treatment for latent TB?
INH + vitamin B6 for 9 months
Rifampin for 4 months
What is treatment for CMV?
Valganciclovir
What are next steps in a patient with a positive PPD?
Rule out active infection with a CXR/symptoms
If no active infection, treat as latent TB
How are post-exposure HIV patients treated?
Treated with two nucleoside analogs (tenofovir/emtricitabine) + integrase inhibitor (raltegravir) for a month
How is scabies treated?
Treat with permethrin cream. Ivermectin is first line only in crusted scabies. Wash clothing and linens in hot water. Place other items in airtight plastic bags for several days.
Can interferon gamma release assay distinguish between active or latent TB
No
What does E coli 0157:H7 cause?
5-10% of patients can have hemolytic uremic syndrome (uremia/hemolytic anemia/thrombocytopenia)
What are some uses of clindamycin? (3)
What is a major side effect of clindamycin?
Clindamycin covers MRSA, decreases toxin production by Strep pyogenes and Staph aureus, and treats anaerobic infections above the diaphragm
Side effect - C diff
What antibiotics can be used to treat CAP empirically?
Cephalosporins (Rocephin)+ Macrolides (azithromycin)
Respiratory Fluroquinolones (Levofloxacin)
HIV
When should be rifabutin be used over rifampin in TB patients and why?
Use rifabutin over rifampin in HIV patients with TB because rifabutin has fewer drug-drug interactions with ARTs
What part of the lung does primary TB affect? What does it form?
The lower lobes of the lung. Forms Ghon Complex. “Started from the bottom now we here”
What part of the lung does secondary TB affect?
Secondary TB is reactivated latent TB. It affects the upper lobes.
Do entamoeba histolytica liver abscess require treatment?
No
How is HSV encephalitis diagnosed?
PCR of CSF after LP
What are atypical causes of CAP? (3)
Chlamydia
Mycoplasma
Legionella
Endocarditis
What two bacteria cause endocarditis or bacteremia and warrant colonoscopy/EGD?
Strep bovis
Clostridium septicum
What strains of HPV do HPV vaccines protect against? Who should get this vaccine?
6, 11, 16, and18 . Males and females 9-26 years of age should get the HPV vaccine.
When is candidiasis infection always treated? What is used for treatment in these cases?
When should fluconazole be used in these cases?
Treat in candidemia (blood cultures showing candidasis infection). Use echinocandin if patients are moderately/severely ill or neutropenic or if there is a possibility of fluconazole resistant organism.
Use fluconazole if candidemia is caused by UTIs or CNS infection
What are penicillins great for treating? What did bacteria develop against penicillin?
Penicillins are great for treating gram positive (ie skin flora). Bacteria developed penicillinase to counteract penicillins.
What are three penicillinase resistant pencillins?
Methicillin/Oxaficillin/Naficillin
What are gram positive cocci that are catalase positive? What is their morphology on microscopy?
Staphylococcus. Clusters or grapes of Staph
What is an example of a monobactam?
Aztreonam
What do monobactams cover? What do they not cover?
Monobactams cover gram negative organisms and pseudomonas.
Does not cover anaerobes
What is treatment for HSV and VZV encephalitis?
IV acyclovir (oral does not penetrate CSF)
How does CNS toxoplasmosis and CNS lymphoma typically present on MRI in HIV patients?
Toxoplasmosis is usually multiple ring enhancing lesion. CNS lymphoma is usually a single ring enhancing lesion.
T/F - Can tuberculin skin testing determine between active or latent TB?
No
T/F BCG vaccine may cause false positive TB skin tests?
True
Should BCG vaccination status should be taken into account when interpreting Tuberculin skin tests?
No. If a patient is from endemic country or is at risk for TB, CDC recommends interpreting Tuberculin Skin Tests as you would for someone who did not get BCG
In cellulitis patients, when should Staph Aureus be considered part of the etiology?
When you see pustules, abscesses, or purulent drainage.
How does primary TB present?
Primary infection is usually asymptomatic. 90% of patients who are immunocompetent control the infection and develop clinically silent latent infection.
How does active TB present?
Symptoms of active infection include cough, hemoptysis, weight loss, fever, and night sweats
How do post-splenectomy patients with encapsulated bacterial infection present?
Viral prodrome followed by abrupt deterioration and shock
What should be done in all patients with non-tunneled CRBSI?
Remove non-tunneled catheters if CRBSI is confirmed.
When should TEE be done in CRBSI?
Perform TEE in cases of Staph Aureus CRBSI
Endocaritis
What are physical exam signs associated with endocarditis?
Fever and regurgitant murmurs are most common. Petechiae is common as well.
- Splinter hemorrhages
- Roth spots - retinal hemorrhages
- Osler nodes - painful nodes on palms/feet
- Janeway lesions - non-tender nodules on palms/soles
- Conjunctival hemorrhages
Doxycycline can treat all tick-borne illnesses except what?
Babesia
What do echinocandins end in?
- Fungin
What are two lung manifestations of MAC?
Bronchiectasis and upper lobe cavitary lesions
What form of TB is transmittable (active or latent)?
Active TB is transmissible
How does pelvic inflammatory disease present?
Purulent endocervical drainage
Fever, lower abdominal pain that is bilateral.
Cervical motion tenderness and adnexal tenderness
What is Fitz-Hugh Curtis syndrome and what does it indicate?
RUQ pain from perihepatitis seen in pelvic inflammatory disease
Endocarditis
What are five indications for surgery during active endocarditis?
- Prosthetic valve endocarditis
- Fungal endocarditis
- Perivalvular extension - new conduction abnormalities, myocardial abscess, persistent bacteremia despite antibiotics)
- Vegetative burden - size > 10 mm or recurrent embolic events despite antibiotics
- Refractory CHF
When are stool cultures considered in patients with diarrhea? (3)
Stool cultures are generally low yield, although they may be considered in patients with:
- Fever
- Bloody diarrhea
- Diarrhea lasting longer than 72 hours
How does bacterial vaginosis present?
White discharge/white non-inflammatory coating
How does bacterial vaginosis appear on microscopy? (3)
- Clue cells on microscopy.
- Vaginal pH > 4.5
- Positive whiff test (fishy odor with addition of 10% KOH
Treatment for bacterial vaginosis?
7 day course of metronidazole BID
How is chlamydia diagnosed and how is treated?
Diagnosis is via NAAT of urine in men. Women need cervical swab. Treatment is azithromycin/doxycycline
What does acid-fast stain show in patients with suspected TB?
Just shows acid-fast bacilli which can be various strains of mycobacteria.
Acid-fast stain is not sensitive nor specific for mycobacterium TB.
When does arbovirus (West Nile) encephalitis present?
Summer and fall
WHEN does HSV encephalitis present?
Typically winter and spring
How does West Nile encephalitis present?
Encephalitis and acute asymmetric flaccid paralysis that may progress to respiratory failure
How does Creutzfeldt-Jakob prion disease present?
Rapidly progressive dementia, myoclonus, ataxia, and spasticity
What is treatment for pregnant women with UTIs? (4)
MS
Seven day course of amoxicillin-clavulanate, nitrofurantoin, cefpodoxime, or cefixime.
Urinary Tract Infections
What are treatment options for uncomplicated cystitis? (2)
What should be avoided as first line in uncomplicated cystitis patients and why?
- 5-day course of nitrofurantoin
- Three day course of TMP-SMX - do not use if there is > 20% resistance of E coli in the community
- 2nd line = single 3 gram dose of fosfomycin
Avoid fluoroquinolones due to resistance and toxicity issues
Urinary Tract Infections
(MS) What are treatment options for complicated cystitis and pyelonephritis? (1)
What medications should be avoided in pyelonephritis and why?
- Fluoroquinolones
Avoid Nitrofurantoin, TMP-SMX in pyelonephritis because it does not penetrate the kidneys
Urinary Tract Infections
(MS) Which imaging study is more sensitive for perinephric abscess? What is first line imaging study?
- CT scan is more sensitive
- US is first line.
Urinary Tract Infections
(MS) How does acute bacterial prostatitis present? How is it treated and for how long?
Urinary frequency, dysuria, perineal pain and referred penile tip pain
All antibiotics penetrate well into prostatic tissues during acute infection. Treatment is for a total of 4 weeks
Urinary Tract Infections
(MS)
What types of prostatitis require treatment?
- Type 1 (acute bacterial prostatitis) and Type 2 Prostatitis (chronic bacterial prostatitis)
Urinary Tract Infections
(MS) How does chronic bacterial prostatitis present?
How is chronic bacterial prostatitis treated?
Cystitis and persistent/recurrent bacteruria.
Treatment should be with alkaline agents (Fluoroquinolones and TMP-SMX) since chronic prostitis leads to an acidic prostate
Urinary Tract Infection
How is CAUTI (catheter associated UTI) differentiated from catheter associated asymptomatic bacteriuria? Which one is treated?
CAUTI is diagnosed if a patient has symptoms such as fever, malaise, AMS, hematuria, or costovertebral angle tenderness.
Treat CAUTI. Don’t treat catheter associated asymptomatic bacteriuria.
What microorganisms are responsible for meningitis in patients aged 18-50 and what is empiric treatment?
Streptococcus pneumonia and Neisseria
Empiric treatment is vancomycin and rocephin (can use cefotaxime instead of ceftriaxone)
What micro-organisms are responsible for meningitis in patients > 50 years of age? What is empiric treatment?
Streptococcus pneumonia, Gram negative bacilli, and Listeria.
Empiric treatment is Vancomycin, Rocephin (or cefotaxime), and Ampicillin
(MS) Describe normal CSF findings in patients in terms of WBC, Glucose level, and Protein Level?
WBC < 5. No PMN
Glucose 50-75
Protein < 45
(MS) What findings are seen in Bacterial meningitis in terms of WBC, Glucose, and Protein?
WBC > 1000 with majority of cells being PMN
GLucose is low (<50)
Protein is > 100
(MS) What are findings of aseptic viral meningitis in terms of WBC, Glucose, and protein?
WBC is elevated but < 1000 and PMN initially then monocytes and lymphocytes
Glucose is normal (50-75)
Protein is < 100
What are micro-organisms associated with meningitis in patients with impaired cellular immunity? What is empiric treatment?
Strep pneumo
Listeria
Gram negative organisms (including pseudomonas)
Treatment with Vancomycin, Cefepime and Ampicillin
What are micro-organisms associated with meningitis in post-neurosurgery patients/hospital acquired bacterial meningitis and what is empiric treatment?
Strep pneumo
Staph aureus
Gram negative organisms (including pseudomonas)
Empiric treatment is vancomycin and cefepime (or ceftazidime or meropenem)
What should always be given in patients with suspected bacterial meningitis?
Always give steroids in addition to antibiotics
In patients with bacterial meningitis, what two groups of organisms are always seen in patients with recent NS, impaired cellular immunity, and age > 50?
Strep pneumo
Gram negative organisms
What are substitutes for patients with penicillin allergies in bacterial meningitis treatment?
Ampicillin substitute?
Rocephin substitute?
Use IV moxifloxacin instead of rocephin
Use TMP-SMX instead of ampicillin
What are gram positive organisms that are catalase -? (3) How do they appear on microscopy?
Streptococcus
Strep pneumo
Enterococcus
Strep = strip = pairs/chains on microscopy
What are causes of chronic meningitis (2)? What do CSF findings show in terms of WBC, glucose and protein?
TB and Fungi
WBC is elevated with lymphocytes
Glucose is decreased and protein is increased.
What are two causes of spirochetal meningitis? What do CSF findings show in terms of WBC, glucose, and protein?
Syphilis and Lyme
CSF shows increased lymphocytes and WBC, NORMAL GLUCOSE, and elevated protein
Similar to aSeptic meningitis Spirochetal meningitis = Syphilis/Lyme
When should CT scan be performed prior to LP in patients? (4)
Perform CT scan prior to LP if patients have had seizures, focal neurological deficits, papilledema, or immunocompromised state (age > 60)
Why are all patients with suspected bacterial meningitis given dexamethasone (in other words coverage for what organism)?
Dexamethasone decreases morbidity and mortality in adults with pneumococcal meningitis
What should be used as prophylaxis for exposure to meningococcal meningitis? (3)
- Rifampin
- Ciprofloxacin
- Ceftriaxone
Who should get prophylaxis after exposure to meningococcal meningitis? (3)
- Household contacts
- Anyone exposed to salivary/respiratory secretions
- Healthcare workers who were exposed to patient’s secretions without proper PPE
Neisseria Meningitidis morphology on gram stain?
Gram negative dipplococci
TB meningitis key physical exam finding?
Lyme disease key physical exam finding?
TB meningitis can present with cranial nerve palsy
Lyme disease can present with peripheral and cranial nerve palsies
What organism is most likely to cause spinal epidural abscess?
How does spinal epidural abscess present?
Staph Aureus
Presents as back pain, fever, radiculopathy
How do brain abscesses typically form?
Contiguous spread from nearby infections caused by organisms involved in sinusitis, dental infections, otitis media
What are symptoms of brain abscesses? (4)
Fever, severe headaches, focal neurological deficits, and seizures
What animals are associated with rabies?
Bats
Raccoons
Skunks
Foxes
Dogs
Cats
Ferrets
How does rabies present?
1-3 months after exposure presents as a viral prodrome followed by encephalitis, ASCENDING PARALYSIS, hydrophobia, aerophobia, and delirium
When should patients receive rabies prophylaxis?
What animal bites should have the wait and see approach for rabies?
What animal bites never require rabies prophylaxis?
Bites from bats, raccoons, foxes, and skunks are considered high risk and warrant prophylaxis.
Pets such as dogs, cats, ferrets can be observed for signs of rabies for 10 days and if there are no signs of rabies there is no need for rabies prophylaxis.
Bites from small rodents (rats/squirrels) never require rabies prophylaxis
How does Creutzfeldt-Jakob disease present?
Myoclonus and rapidly progressive dementia
How does Creutzfeldt-Jakob disease present on EEG and CSF?
CSF may show 14-3-3 protein.
EEG shows synchronous biphasic or triphasic sharp wave complexes
What organism typically causes acute otitis media and how is acute otitis media empirically treated?
Caused by Strep pneumo.
Treatment is amoxicillin/clavulanate if the patient has not taken antibiotics recently.
At first glance, using amoxicillin appears to be an odd choice for the treatment of an infection caused by bacteria that are often penicillin resistant. However, when given in high doses, amoxicillin achieves levels in the middle ear that exceed MIC of all but the most highly penicillin resistant Strep. Pneumo Strains.
What organism causes acute otitis externa and how is it typically treated?
Pseudomonas. Use topical fluoroquinolone
What is malignant otitis externa and how does it present? Causative organism?
Malignant otitis externa is otitis externa that progresses to an invasive and destructive infection of the soft tissue and bone with potential to invade meninges and brain.
Caused by pseudomonas.
How is HIV treated? ART?
Two nucleoside analogs (emtricitabine) (tenofovir)
plus one of the following
Non-nucleoside analog
Protease inhibitor
Integrase inhibitor (Raltegravir)
How should Prep (pre-exposure) HIV patients be treated?
Daily tenofovir/emtricitabine (two nucleoside analogs)
What groups of organisms cause intra-abdominal infections?
What is empiric antibiotic coverage for Intra-abdominal infections?
- Gram negative bacilli - E coli/Klebsiella/(Pseudomonas - in healthcare settings)
- Anaerobic infections
- Gram positive cocci (Strep + Enterococcus - VRE)
Treatment regimens that cover all three are either carbapenem monotherapy or Zosyn monotherapy.
OR
Cephalosporin covers #1 and #3 and use flagyl to cover # 2.
What are non-treponemal tests and what are treponemal tests?
How is each group of test used?
Non-treponemal tests include - VDRL and RPR - used for screening, testing for repeat infections, and for monitoring treatment responses. Titers wane and revert to negative with time and adequate antibiotic treatment.
Treponemal tests - FTA/ABS and MHA-TP are used to confirm VDRL and RPR tests. Antibodies remain positive for life and so it is not useful for testing for repeat infections.
Name the aminoglycosides
What are aminoglycosides good at covering?
What are the side effects of aminoglycosides?
What are aminoglycosides not good at covering?
Mean GNATS cannot kill anaerobes.
Gentamicin
Neomycin
Amikacin
Tobramycin
Streptomycin
Cover gram negative organisms but not anaerobes.
Side effects - (similar to vancomycin) - Nephrotoxicity and Ototoxicity
Name two third generation cephalosporins?
Which one covers pseudomonas?
Third generation cephalosporins for the following groups of organisms - gram positive/gram negative/anaerobic coverage?
Ceftriaxone
Ceftazidime - Covers pseudomonas
Gram positive - not great at Staph coverage. Good pneumococcus coverage.
Gram negative - Great gram negative coverage.
No anaerobic coverage.
Uses - Pneumonia (not HAP)
What are the aminopenicillins? What are they used to treat? What did bacteria develop to counter aminopenicillins? What did we develop to counter this bacterial adaption?
Aminopenicillins are Ampicillin/Amoxicillin
Cover gram positive and some easy gram negative organisms.
Bacteria developed beta lactamase to counter aminopenicillins.
We developed beta-lactamase inhibitors such as:
Unsyn = Ampicillin + Sulbactam
Augmentin = Amoxicillin + Clavulanic acid
Sulbactam and Clavulanic acid
Fever of Unknown Origin
Define Fever of Unknown Origin?
What are the three most common causes of FUO?
Fever > 100.9 for three weeks without an etiology despite two outpatient visits and three days of inpatient evaluation
Most common causes are infections, rheumatic diseases, and malignancies.
What should be avoided in FUO?
Avoid antibiotics unless a patient is clinically unstable.
When should you suspect SBP in a patient with primary peritonitis?
Typical treatment regimen for SBP?
If peritoneal fluid shows > 250 polymorphonuclear leukocytes.
Treat with third generation cephalosporin.
What 3 groups of patients should receive antibiotic prophylaxis for primary peritonitis?
What medications should be used as prophylaxis?
- Patients with cirrhosis who have ascitic fluid showing < 1500 protein
- Cirrhosis patients with GI bleed
- Patients with a prior episode of primary peritonitis
Use Ciprofloxacin or TMP/SMX
How should patients with secondary peritonitis be treated?
Surgical intervention with antibiotics like a carbapenem or zosyn
What is contraindicated in patients with suspected brain abscess and why?
Avoid LP due to risk of herniation
How is West Nile encephalitis diagnosed?
What is treatment for West Nile encephalitis?
Diagnosis is via CSF IgM to WNV
Supportive care, if concern for respiratory failure, move to ICU
True/False. For women with symptoms of uncomplicated cystitis, prescribing antibiotics over the telephone without seeing the patient or obtaining a UA is acceptable
True
Should TMP-SMX be used for UTI treatment if it was taken in the prior three months?
No
Should asymptomatic candiduria be treated with antifungal therapy?
No, instead remove the urinary catheter
What are the pencillinase resistant penicllins and which one is great for MSSA?
Methicillin
Nafcillin
Oxacillin
Use Nafcillin for MSSA
What is a fourth generation cephalosporin?
Gram positive coverage?
Gram negative coverage?
Anaerobic coverage?
Pseudomonal coverage?
Uses?
Cefepime.
Covers pseudomonas
Broad gram positive and gram negative coverage
Does not cover anaerobes
Used in fever of unknown origin and immunocompromised patients
What is treatment for active TB?
RIPE for two months
Rifampin
INH
Pyrazinamide
Ethambutol
Followed by
INH (+ Vitamin B6) and rifampin for four months
Total duration of treatment is six months
How does drug induced fever present and what are some causes of drug induced fever (3)
Drug-induced fever can occur at anytime but usually appears days to weeks after initiation of a new drug. Associated features include rash, urticaria, liver/kidney dysfunction, and mucosal ulceration.
Causes:
- Anticonvulsants - phenytoin/carbamazepine
- Antibiotics - Beta lactams/Sulfonamides/Nitrofurantoin
- Allopurinol
What are the extended spectrum penicillins? What did bacteria develop to counter these antibiotics? What did humans develop to counter this adaptation?
What are extended spectrum penicillins good for covering?
Penicillin/Ticarcillin
Great for covering gram positive and hard gram negative bacteria (like Pseudomonas)
Bacteria developed beta-lactamases.
Piperacillin with tazobactam (beta lactamase inhibitor)
Ticarcillin with Clavulanic acid (Beta lactamase inhibitor)
How does pyelonephritis present?
When should perinephric abscess be suspected in a patient with pyelonephritis?
Presents with fever, flank pain, urinary symptoms
Suspect perinephric abscess in patients with persistent fevers and symptoms despite medical therapy.
What antibiotics make up the macrolides?
What do they cover?
What are some side effects?
Macrolides - ACE - Azithromycin/Clarithromycin/Erythromycin
Cover atypical respiratory infections (legionella/Mycoplasma/Chlamydia)
Side effects -
MACRO
Motility - increased GI motility
Arrhythmias (prolonged QTc)
Cholestatic hepatitis
Rash
eOsinophilia
What are four categories/shapes of gram negative bacteria?
- Bacilli (SSEKP)
- Coccobacilli - H influenzae/Bordetella
- Diplococci - Neisseria meningitidis/Neisseria gonorrhoeae
- Curved rods - H pylori, Vibrio, Campylobacter
What are the risk factors for MRSA cellulitis (4)?
- Recent antibiotic use
- Recent healthcare exposure
- Prior MRSA infection/MRSA colonization (nares)
- Purulent drainage
Define ventilator associated pneumonia and hospital acquired pneumonia
Hospital acquired pneumonia is defined as pneumonia occurring greater than 48 hours after hospital admission.
Ventilator based pneumonia is that occurring greater than 48-72 hours after intubation.
True/False - An IV catheter related infection can present as sepsis without symptoms localizing to the line or as a localized infection of the subcutaneous tunnel and/or the exit site with purulence and erythema at the site.
True
When a central line associated blood stream infection is suspected, how many blood cultures should be obtained and from where?
What should no longer be cultured?
Obtain two peripheral IV cultures.
Culturing blood through the line is no longer recommended. Culturing the tip of the line is also no longer recommended if the line is removed.
What organisms are likely to cause CLABSI? (5)
Staph aureus, enterococci, Enterobacteriaceae, Candida, or Bacilli
Once the line is removed in a CLABSI, how long should treatment be? (2)
- Treat for 14 days after last negative blood culture.
- For Staph aureus, treat for 4 weeks.
Endocarditis
What is the definition of early and late prosthetic valve endocarditis?
Early PVE - within 2 months of valve insertion.
Late PVE - occuring greater than 2 months after valve insertion.
Endocarditis
In a patient with endocarditis with the following history, what is the most likely cause of endocarditis:
- Skin infections
- Dental work
- Genitourinary manipulation or obstruction.
- IV catheters
- IV drug use (3)
- Skin infections - Staphylococci
- Dental work - Viridans streptococci
- Genitourinary manipulation or obstruction - enterococcus
- IV catheters - Staphylococci
- IV drug use - Staph aureus, Gram negative bacilli (GNB), or yeast.
Endocarditis
What is the definition of culture negative endocarditis?
What are some causes of culture negative endocarditis? (Name 4, not all)
When three sets of blood cultures are negative, there is no history of preculture antibiotic treatment and the patient has endocarditis
Causes:
1. Fungi
2. Q fever (Coxiella burnetii)
3. Bartonella
4. Tropheryma whipplei
5. Legionella pneumophila
6. Chlamydia psittaci
7. Abiotrophia
Endocarditis
What is the first imaging modality for suspected Endocarditis?
When should TEE be performed in patients with suspected endocarditis? (2)
TTE is first imaging modality of choice for suspected endocarditis
Perform TEE when:
1. Endocarditis is suspected and patient has a non-diagnostic TTE
2. Intracardiac device leads are present in patients
Endocarditis
What are the HACEK causes of endocarditis?
How long do they take to grow in vitro?
What is the treatment for HACEK organisms?
HACEK
- Haemophilus
- Aggregatibacter aphrophilus/Aggregatibacter actinomycetemcomitans
- Cardiobacterium hominis
- Eikenella Corrodens
- Kingella Kingae
Shows growth in vitro (mean of three days)
HACEK organisms are susceptible to ceftriaxone
Endocarditis
How many blood cultures need to be positive for Coxiella Burnetii to be considered a source of endocarditis?
One blood culture needs to be positive for Coxiella Burnetii to be considered a source of endocarditis
Endocarditis
What are typical organisms that cause endocarditis and therefore require two positive blood cultures to meet the major Duke’s criteria for positive blood cultures? (5)
- Staph aureus
- Viridans Streptococci
- Streptococcus bovis
- Enterococci
- HACEK organisms
Endocarditis
Treatment regimen for Viridans Streptococci endocarditis? (three options)
Four weeks of penicillin G, ampicillin, or ceftriaxone
Endocarditis
Native valve endocarditis
MSSA empiric treatment?
MRSA empiric treatment?
MSSA - Nafcillin for six weeks
MRSA - Use Vancomycin for six weeks. However if MIC > 1, use daptomycin
Endocarditis
Treatment for HACEK endocarditis?
Ceftriaxone for 4 weeks
Endocarditis
What two patient populations are considered high risk for acquiring endocarditis and what are the procedures they require prophylaxis for?
Patients considered high risk for endocarditis are those with prosthetic cardiac material (valves, cyanotic congenital heart disease) or a prior history of endocarditis
Only procedures that require prophylaxis are dental procedures that cause bleeding because of the manipulation of the gingiva or periapical areas of perforation of the oral mucosa.
Respiratory tract procedures that cut through the mucosa, such as tonsillectomy or bronchoscopy with biopsy.
Endocarditis
What is endocarditis prophylaxis for dental procedures/respiratory tract infections?
How about for penicillin allergic patients (4 options)?
Give a single dose of amoxicillin 30-60 minutes prior to procedure.
For Penicillin allergic patients, give a single dose of cephalexin, clindamycin, clarithromycin, or azithromycin.
Cardiac implantable electrtonic device infections
What are two ways that cardiac implantable electronic device infections can present?
Infection can be limited to tissue in which the device is placed (pocket infection) that presents with pain, erythema, swelling and sometimes systemic symptoms.
A deeper infection presents with systemic symptoms such as fever, chills
Cardiac Implantable electronic device infections
Describe diagnostic testing for CIED (cardiac implantable electronic device) infections
How are CIED infections treated?
Perform TEE (not TEE) as initial imaging modality. Obtain three sets of blood cultures at least one hour apart.
Treatment consists of removal of device and initial of empiric antibiotics to cover MRSA for at least 10-14 days.
What organisms are not commonly seen in neutropenic sepsis?
- Anaerobic bacteria are not commonly seen in neutropenic sepsis
Define febrile neutropenia
Temperature > 101 for one occurrence or 100.4F for 1 hour and severe neutropenia defined as ANC < 500 or expected to be < 500 in the next 48 hours.
What are three treatment options for febrile neutropenia?
Initial treatment is directed against gram negative organisms including Pseudomonas.
Treatment should be one of the following:
1. Zosyn
2. Carbapenem
3. Cefepime
When should vancomycin be included in patients with febrile neutropenia? (5)
Include vancomycin if any of the following are present:
- Hypotension or severe sepsis
- Positive blood culture for GPB
- Pneumonia
- Skin infection or erythema at site of indwelling catheter
- History of MRSA or prior colonization
When should fungi be considered a source of febrile neutropenia and how should it be treated? (2 treatment options)
- Consider fungal infection as a source of febrile neutropenia if fever and neutropenia persist for 4-7 days on empiric antibiotics.
Treatment should be with an echinocandin or voriconazole.
Use Voriconazole if there is concern for pulmonary infiltrates because voriconazole more predictably treats Aspergillus infection.
What are two clinical findings that are predictive of bacterial sinusitis?
- Duration of symptoms > 10 days
- Worsening of symptoms after an initial improvement that occurs > 3 days
How are most cases of viral sinusitis treated and what is not recommended?
Use intranasal saline
Avoid decongestants or antihistamines
What are the three most common causes of bacterial sinusitis?
- Strep pneumo
- H influenzae
- Moraxella catarrhalis
HMS titanic
Same three causes of acute otitis media.
How can mucormycosis present in patients?
A patient with rhinocerebral mucormycosis can present with a signs and symptoms of a typical sinus infection. Tissue necrosis occurs as infection spreads outside of the sinuses with distinctive black eschar seen on the palate and/or nasal mucosa
Agents for empiric treatment of bacterial sinusitis?
(One first line and two second line agents); (Adjunctive treatments?)
- Augmentin - first line
- Fluoroquinolones - second line
- Doxycycline - second line
Can use intranasal steroids and intranasal saline as adjunctive treatments.
Avoid decongestants and antihistamines
When should radiography (CT or MRI) be employed in sinusitis patients
If a patient fails empiric treatment or has frequent relapses. Look for a structural abnormality.
Empiric treatment for the following:
- Submandibular space infection/Ludwig Angina
- Lateral pharyngeal space infection
- Retropharyngeal space infection
- Unsyn
What symptoms make Group A Beta-hemolytic Streptococcal (GABHS) infections more likely? (3)
What is initial test for Group A beta-hemolytic Streptococcal infections? When should additional testing be ordered?
Lack of cough
Lack of voice hoarseness
Lack of a runny nose
Rapid-antigen detection test is first line diagnostic test for adults with suspected GABHS. If Rapid-antigen detection test is negative in patients with high exposure to children/adolescents such as school teachers or day care workers, obtain cultures.
What is empiric treatment for GABHS and when should empiric treatment be started?
What does treatment help reduce the risk of?
Start within 72 hours of symptoms.
Treat with oral penicillin or amoxicillin.
Reduces the risk of peritonsillar abscess and rheumatic fever if given within 72 hours of symptom onset.
How does Epiglottitis present and how can it be differentiated from pharyngitis? (Three differentiating symptoms and two common symptoms)
Sore throat and dysphagia can be seen in both Epiglottitis and pharyngitis but Epiglottitis can be differentiated from pharyngitis because Epiglottitis patients have stridor/drooling/hot potato voice
What is the most common cause of purulent cellulitis?
What is the most common cause of non-purulent cellulitis?
Most common cause of purulent cellulitis is Staphylococcus.
Most common cause of non-purulent cellulitis is Streptococcus pyogenes.
What is empiric treatment for mild purulent cellulitis (2)?
- TMP-SMX
- Doxycycline
What is empiric treatment for mild non-purulent cellulitis (3)?
- 1st generation cephalosporin like cephalexin
- Penicillin
- Clindamycin
How does erysipelas and what causes it?
Streptococcal lymphangitis characterized by well-demarcated raised borders affecting the superficial dermis and lymphatics.
How is Pasteurella multocida transmitted to Humans and what is empiric treatment?
Spreads via animal bite.
Treatment is Augmentin
Morphology of Vibrio Vulnificus?
How does Vibrio Vulnificus spread?
Empiric treatment? (3)
Gram negative bacilli (curved rod)
Found in warm, coastal, brackish water.
Empiric treatment is either ceftriaxone, doxycycline or fluoroquinolone.
What does mycobacterium marinum cause?
Empiric treatment for severe disease (3)
Causes non-healing ulceronodular skin lesions when inoculated onto the skin in patients exposed to freshwater or saltwater (ie fishtanks).
Empiric treatment for severe disease is clarithromycin + ethambutol + rifampin
Endocarditis
Prosthetic valve endocarditis treatment:
- MSSA?
- MRSA?
- MSSA - Nafcillin + rifampin + gentamicin for six weeks
- MRSA - Vancomycin + rifampin + gentamicin
Treatment for Enterococci Endocarditis (time frame and agenets)
Native valve? - 2 agents
Prosthetic valve? - 2 agents
Native valve - PCN + gentamicin for 4 weeks
Prosthetic valve - PCN + gentamicin for 6 weeks
How do septic joints form? (2)
What is the usual WBC count found in synovial joints after tap?
- Contiguous spread - nearby adjacent cellulitis, trauma or surgery)
- Hematogenous spread
WBC > 40,000
Empiric treatment for septic joint if gram stain shows:
- gram positive cocci?
- Gram negative bacilli?
- Gram positive cocci, treat empirically with IV vancomycin
- Gram negative bacilli - 3rd generation cephalosporin
Definitive therapy will be based on culture results.
Patients may require repeated taps if synovial fluid accumulates to prevent further joint damage from inflammatory fluid.
True/False
Having a prosthetic joint is a major risk factor for septic arthritis
True
What are the organisms that usually cause septic arthritis in prosthetic joint infections? (2)
Staph aureus and coagulase negative Staphylococci
True/False - CT/MRI can definitively help identify prosthetic joint septic arthritis?
False. Definitive diagnosis is made by joint aspiration.
What is the most common cause of osteomyelitis in the following groups of patients:
Sickle cell patients?
Acute osteomyelitis?
IV drug users (2)?
Sickle cell patients - Salmonella
Acute osteomyelitis - Staph aureus
IV drug users (2) - Pseudomonas and Serratia
Describe two ways for diagnosing diabetic foot osteomyelitis?
What imaging can be used to diagnose osteomyelitis and what is the time frame for this?
- If a solid probe is able to reach the bone on examination.
- Imaging followed by bone biopsies for culture
X-ray can show osteomyelitis if it has been present for at least two weeks. MRI is more sensitive for osteomyelitis that is acute
How is osteomyelitis treated?
Using imaging and await bone biopsy before starting empiric antibiotic therapy (improve culture yield). If patient is hemodynamically unstable, start empiric antibiotics.
What are three problems that can be caused by animal bites?
What animal bites are most likely to cause bacterial infections (in descending order)?
- Bacterial infections (human bites, followed by cat bites, and finally dog bites in descending order for risk of infection).
- Tetanus
- Rabies
What is empiric therapy for all animal bites
Augmentin (Amoxicillin/Clavulanate)
Gastrointestinal Infections
What are three bacteria that produce illnesses from the ingestion of toxins?
What is the time frame for illnesses from these toxins
- Staph aureus
- Bacillus cereus
- Clostridium perfringens
Usually nausea, vomiting, diarrhea, abdominal cramps that are < 24 hours or 1-2 days.
Gastrointestinal Infections
What are two common viruses known to cause gastroenteritis and what age group of patients is affected?
Treatment for these viruses?
- Rotavirus - causes severe diarrhea in infants/children
- Norovirus - most common in adults.
Supportive care, there are no anti-virals active against these viruses.
Gastrointestinal Infections
Majority of causes of Traveler’s diarrhea is from what four bacteria?
- Enterotoxigenic E coli
- Salmonella
- Campylobacter
- Shigella
Gastrointestinal Infections
Two tests to determine invasive bacterial cause of patient’s diarrhea? Which test is more specific?
- Check WBC in stool
- Stool lactoferrin - More specific test
Gastrointestinal Infections
Who should receive prophylaxis for Traveler’s diarrhea and what are two prophylactic medications for Traveler’s diarrhea? (2)
What can be used as treatment for Traveler’s diarrhea (3)?
Prophylactic antibiotics should be given to those who are immunodeficient and those with chronic medical conditions (IBD, cardiac or kidney disease).
Prophylaxis agents:
1. Ciprofloxacin 500 mg daily
2. Rifaximin 200 mg daily or BID
Treatment of Traveler’s diarrhea
- Ciprofloxacin
- Azithromycin
- Rifaximin
Endocarditis
Five common causes of endocarditis and associated treatments?
- Staph aureus - Vancomycin
- Viridians Streptococci - Penicillin G/Ampicillin/Ceftriaxone
- Strep bovis
- Enteroccoci - Penicillin and Gentamicin
- HACEK - Ceftriaxone
Endocarditis
When should you be worried about a perivalvular or myocardial abscess or septic emboli focus in endocarditis patients?
Recurrent fevers after initial symptom improvement or persistent fever despite one week of appropriate antibiotic use
Fever and Rash
Neutropenic patients with Pseudomonas aeruginosa bacteremia can have what characteristic skin lesions?
Ecthyma gangrenosum - black, necrotic, ulcerative skin lesions
Fever and Rash
Neutropenic patients with candidemia may have what kind of skin findings?
Maculopapular rash that is symmetrical because it is due to the hematogenous spread of the fungus
Fever and Rash
How does toxic shock syndrome present (3) and what is the cause of this?
Associated with Staphylococcus aureus and manifests as fever, hypotension, and a diffuse erythematous sunburn-like rash
Spirochetes
How is Lyme diagnosed? (2)
Lyme is diagnosed by
1. Stage 1 disease - erythema migrans
2. Stage 2 or 3 disease with positive serology. Positive serology is Enzyme Immunoassay followed by positive Western Blot
Spirochetes
Treatment for Lyme disease?
Doxycycline
Spirochetes
How is recurrent Lyme arthritis treated?
Recurrent or refractory Lyme arthritis can be treated with repeat course of same drug and duration one time time only
Spirochetes
Why isn’t serology performed in patients with stage 1 Lyme disease?
Most patients in Stage 1 Lyme erythema migrans are negative for serological testing
Spirochetes
What is post-exposure prophylaxis for Lyme disease?
Single dose of doxycycline
Spirochetes
Ticks require ________ of attachment before transmission of infection occurs?
Ticks require 24-36 hours of attachment before transmission of infection occurs
Spirochetes
What are the three stages of Lyme disease, the predominant symptoms in each stage and the time frame of symptoms?
- Stage 1 - Erythema migrans (early)
- Stage 2: (weeks to months)
* Neurological symptoms such as meningitis; Cranial nerve 7 palsies (bilateral Bell’s palsy)
* Cardiological manifestions such as myocarditis, transient 1st, 2nd, 3rd heart block - Stage 3 (months to years) - Arthritis
Spirochetes
How is Leptospirosis transmitted (3)
Infected animals, contaminated water, rodent urine
Spirochetes
Symptoms of Leptospirosis (1 symptom it is known for)?
Myalgias, fever, headache, Weil disease (severe hepatitis with renal failure).
Known for causing conjunctival suffion - redness of the conjunctiva that resembles conjunctivitis but does not involve inflammatory exudates
Spirochetes
What are three infections carried by Ixodes Scapularis tick?
- Babesia
- Anapplasma
- Borrelia Burgdorferi (Lyme)
Spirochetes
Where is Ixodes Scapularis tick found? (2)
Northeast and Midwest United States
