ID exam 3

What are the 5 major ways SSTI are precipitated?

Open wounds

Trauma

entrapment

compromiSed skin integrity

HematogEnous spread (RaRe)

In what type of situations do SSTI’s occur and what do they generally entale as to pathogens

SSTI’s generally occur in patients with complicated infections already and they may be polymicrobial depending on the patient case

What are the 3 consequences of SSTI’s that occur in complicated infections

Morbidity (can be loss of mobility or limbs, pain)

Physical or emotional stress

Increased healthcare costs

Define the characteristics of: (specify purulence and other key characteristics)

Erysipelas

Non-purulent inflection of dermis

Results in a RED, Raised area that is WARM and tender

Preferably occurs in the lower extremities

Define the characteristics of: (specify purulence and other key characteristics)

Cellulitis

Non-purulent infection of dermis AND subcutaneous tissues

Diffuse RED, swollen area, warm and tender

Preferably in the lower extremities

Define the characteristics of: (specify purulence and other key characteristics)

Impetigo

Most commonly occurs in children

Purulent! red sores that may burst and develop HONEY-COLORED CRUSTS

Can exist in bullous and nonbullous appearances.

most common during hot, humid weather on hands, face, and feet

Define the characteristics of: (specify purulence and other key characteristics and CAUSED BY) Furuncle

Purulent infection of a singular hair follicle

Focal area of redness, warmths, swelling, and tenderness

Caused by Staph aureus

Define the characteristics of: (specify purulence and other key characteristics and caused by): Carbuncles

Purulent infection of multiple adjacent hair follicles

Focal area of redness, warmths, swelling, and tenderness

Primarily caused by staph aureus

Define the characteristics of: (specify purulence and other key characteristics and caused by)

Abscesses

Purulent infection of dermal tissue

Focal area of redness, warmths, swelling, and tenderness

primarily caused by staph aureus

What are the 4 primarily signs of a necrotic infection?

Marked fever, chills, leukocytosis, and pain in affected area that may be disproportionate to initial presentation

What are the 3 signs of a necrotic infection?

Affected area initially resembles cellulitis without demarcated margins

Rapid, progressive infection with frequent development of a maroon/violet color

Affected area often shiny, exquisitely tender, and VERY painful

Necrotizing fasciitis typically effects what?

What is a key characteristics of the necrotizing area?

How many types are there and what are their prevalences?

NF is a rapidly-advancing necrotic infection that affects fascia

The affected fascia begins to have an almost wooden induration

There are 3 types

Type 1 occurs most often at \~80%

Type 2 occurs second most often at 15%

Type 3 (gas gangrene) is the most rare at only 5% occurrence

Type 3 of necrotizing fasciitis is gas gangrene which is also called?

How is it characterized?

clostridial myonecrosis

It is a rapidly advancing necrotic infection with PROMINENT GAS PRODUCTION that involves muscle. Typically occurs after surgery or trauma

There are a lot of bacteria that can cause SSTI’s. What are the 2 most common gram + bacteria?

Staphylococcus aerus

Streptococcus pyogenes (group A streptococcus)

What empiric coverage needs to be done for: Cellulitis

Strep pyogenes, MSSA

What empiric coverage needs to be done for: Erysipelas

Steprococcus pyogenes and MSSA

What empiric coverage needs to be done for: Impetigo

MSSA and MRSA

What empiric coverage needs to be done for: human/animal bites?

pyogenes, MSSA, anaerobes, and enteric gram negatives (widely varies based on bite)

What empiric coverage needs to be done for: Purulent infections

Pyogenes MSSA MRSA and others

What empiric coverage needs to be done for: Necrotizing fasciitis

look for broad empiric coverage that will cover everything especially pyogenes, enteric gram negatives, and anaerobes

In the case of human bite wounds, what is the primary bacteria involved and what else should be empirically covered?

What are the common human oral anaerobes that need covered?

streptococcus pyogenes and anaerobes primarily need to be covered.

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Eikenella corrodens and peptostreptococcus are the most common oral human anaerobes

What pathogens are primarily present in animal bites that differ from human bites? What is present in cats that aren’t present in humans/dogs?

Pasturella canis and pasturella cultocida are found in animal bites

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Pasturella multocida is found in cats but not dogs/humans

What types of cultures should be done for animal/human bites?

Wound aspirations

secretions (exudate or pus)

Wound Swab

Surgical Cultures (like a debridement)

In the case of necrotizing fasciitis, symptoms can GREATLY vary on a case to case basis. Classic symptoms like fevers and cutaneous manifestations may be not be present and imaging may not be helpful. What is characteristically almost always present?

Severe attributing pain to injury or procedure

Some systemic manifestations like NVD may occur as is present with any group A streptococcal infection

When triaging patients with SSTI’s, what do we define as mild, moderate, and severe and when should they be hospitalized?

Mild: Local infection with NO systemic signs of illness

Moderate: Local infection with systemic signs of illness +/- hospital admission

Severe: Sepsis, failed incision & drainage attempt, deeper infection, or immunocompromised status

What nonpharm option can be done for furuncles?

A warm, moist compress

Treatment options for a nonpurulent (necrotizing infection/cellulitis/erysipelas)

MILD or MODERATE SSTI

Mild: oral Rx of penicillin VK or cephalosporin or dicloxacillin or clindamycin

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Moderate: IV Rx of Penicillin or ceftriaxone or cefazolin or clindamycin

Treatment options for a nonpurulent (necrotizing infection/cellulitis/erysipelas)

Severe (3 steps)

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What if you find:

Pyogenes

clostridial sp

Vibrio vulnificus

Aeromonas hydrophila

1. surgical exploration if needed
2. Empiric Rx of Vanco and Zosyn
3. culture/swab and narrow therapy

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Pyogenes --- Penicillin + Clindamycin

clostridial sp --- Penicillin + Clindamycin

Vibrio vulnificus --- Doxy +ceftazidime

Aeromonas hydrophila --- Doxy + cipro

Treatment options for purulent (furuncle/carbuncle/abscess):

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Mild

inspect and debridement

Treatment options for purulent (furuncle/carbuncle/abscess):

Moderate

3 steps

1. incision/debridement + Culture/swab
2. Empiric therapy of **bactrim or doxy**
3. Narrow therapy:
* MRSA: Bactrim
* MSSA: dicloxacillin OR Cephalexin

Treatment options for purulent (furuncle/carbuncle/abscess):

Severe

3 steps

1. incision/debridement + Culture/swab
2. Empiric therapy of


1. vanco
2. or linezolid
3. or televancin
4. or ceftaroline
5. or televancin
3. Narrow therapy:
* MRSA: vanco/linezolid/etc.
* MSSA:
* nafcillin, cefazolin, clindamycin

For any form of group A streptococcal necrotizing fasciitis how long must empiric therapy run for?

48-72 hours

What drug that we use is a potent suppressor of toxins produced by staphylococcal and streptococcal pathogens in addition to cytokines produced in infections

Clindamycin

Though there is low quality of evidence may linezolid do to endotoxins?

inhibit toxin production

What is the minimum treatment durations for SSTI’s and what is the acception?

5 days with the acception of necrotizing infections which must be 4-6 weeks

What are neurological sequelae?

neurological deficits that result from neurological damage

What are the 4 steps as to how meningitis occurs within a patient?

Mucosal colonization and bacterial invasion

Bacterial replication in the subarachnoid space

Progressive inflammation

Increased intracranial pressure and cerebral edema

What are NORMAL lab findings for the following?

* WBCs
* Differential
* protein
* glucose
* CSF/blood glucose ratio

* WBCs ---

What are lab findings for Bacterial meningitis?

* WBCs
* Differential
* protein
* glucose
* CSF/blood glucose ratio

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* WBCs --- 1000-5000
* Differential --- neutrophils
* protein --- elevated
* glucose --- low
* CSF/blood glucose ratio --- decreased

What are lab findings for viral meningitis?

* WBCs
* Differential
* protein
* glucose
* CSF/blood glucose ratio

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* WBCs --- 50-1000
* Differential: lymphocytes
* protein: mild elevation
* glucose: NORMAL
* CSF/blood glucose ratio: Normal

What are the lab findings for fungal meningitis?

* WBCs
* Differential
* protein
* glucose
* CSF/blood glucose ratio

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* WBCs: 20-500
* Differential: lymphocytes
* protein: elevated
* glucose: low
* CSF/blood glucose ratio: low

What’s the leading cause of Meningitis? How should it never be treated? What is it predisposed to cause if not taken care of quickly?

Leading cause is streptococcus pneumoniae

NEVER use vanco as monotherapy

High rates of neurologic sequelae

Neisseria meningitidis is generally associated with crowding and is spread through droplets. What are the characteristics of the immune reactions related with this bug?

Fever, arthritis, and pericarditis

Haemophilus influenzae can cause meningitis but rates have decreased recently due to immunization rates. What characteristic symptoms occur?

Ear infection, sinus infections, CSF leaks are risk factors

What is the leading cause of Meningitis in patients > 2 months old?

Streptococcus pneumoniae

When is comes to Listeria monocytogenes:

What populations are we concerned about?

Where can it come from?

Why do we care?

Whats the best way to treat it?

Elderly, neonates, immune compromised, alcoholic

Obtained from the GI tract

High fatality rates makes it concerning

Ampicillin +/- Gentamicin

What is the leading cause of neonatal meningitis?

Streptococcus agalactiae

When approaching treatment, what are the best 5 steps to do in order?

Identify

Lumbar puncture or CT

Empiric antibiotics

adjust per gram stain

adjust per C&S

When should you initial antibiotic coverage begin for patients presenting with meningitis like symptoms?

start them as soon as possible after the diagnosis is considered likely. Even if lumbar puncture has not occurred yet

Empiric therapy for the following age ranges with meningitis:

< 1 mo

1-23 mo

2-50 yo

>50 yo

< 1 mo :: Ampicillin + cefotaxime OR amp + aminoglycoside 1-23 mo :: Vanco + third gen cephalosporin 2-50 yo :: Vanco + third gen ceph >50 yo :: Amp, vanco, third gen ceph

What are the pros of using dexamethasone and when MUST it be given

decreases inflammation, decreases neurologic sequelae in adults with S. pneumoniae meningitis, and decreases neurologic sequelae in children with H. influenzae meningitis

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IT MUST be given with or before the first dose of antibiotics

When considering a medication to be used in a patient with meningitis, what types of medications will most likely not be most effective?

Drugs like Augmentin and Bactrim that have an extra inhibitor will most likely not reach therapeutic levels within the CSF making them weak

What 6 drugs can you NOT use in CSF with or without inflammation?

Aminoglycosides

Amphotericin B

Beta-lactamase inhibitors

Cephalosporins (1st and 2nd gen)

Doxycycline

Itraconazole

Ideal antibiotic properties for treating meningitis

LMW

non-ionized

Lipid soluble

low protein binding

high blood concentration

What two bugs that can cause meningitis should be reported to the local health department?

Neisseria meningitidis

H. Influenzae

What is essential for viral encephalitis treatment?

Supportive care is essential

For HSV what type effects adults and which effects newborns?

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What should be started immediately in coordination with hydration therapy?

Type 1 HSV primarily effects adults

Type 2 HSV primarily effects newborns

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Acyclovir should be started quickly in both adults and newborns with suspected encephalitis even with pending diagnostic tests

When doing empiric coverage for patients with brain abscesses what should be covered and for how long?

Broad spectrum +/-/anaerobes

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Vanco can be added for MRSA

Voriconazole and bactrim can be added in immunocompromised patients

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6-8 weeks

Any form of administration that is not within normal IV administrations must be:

Preservative free

Durations of therapy for the following meningitis causing bugs:

* Neisseria meningitidis
* haemophilus influenzae
* Strep pneumoniae
* strep agalactiae
* Aerobic gram negative stuff
* Listeria monocytogenes

* Neisseria meningitidis - 7 days
* haemophilus influenzae - 7 days
* Strep pneumoniae - 10-14
* strep agalactiae - 14-21 days
* Aerobic gram negative stuff - 21 days
* Listeria monocytogenes - 21+ days

Cryptococcus neoformans is the most common form of fungal CNS infection in the US. How is it gotten

What is it frequently treated with?

inhalation of spore that generally takes over immunosuppressed patients

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Amphotericin B + flucytosine

Amphotericin B

How does it work

Common side effects

Binds to ergosterol altering cell membrane permeabilities and cell death

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Nephrotoxicity, infusion-related reactions, and others

Women are predisposed to be more likely get a UTI over men. What are some causative factors for women? What are some causative factors for men?

Risk factors for everyone?

Women: Sex, cervical diaphragms, spermicidal jellies, pregnancy

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Men: Prostate hyperplasia, uncircumcised

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All patients: Diabetes, physical abnormalities, catheters, or obstructions

Signs of a lower UTI

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Signs of an upper UTI

Lower: Frequency, dysuria/nocturia, hematuria, suprapubic heaviness

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Upper: Fever, chills, flank pain, N/V, malaise, fatigue, pelvic pain, + any lower symptoms

What is a complicated UTI?

Any UTI known to be caused by structural or functional abnormalities. OR any UTI occurring in male patients

What are the most common bugs to cause UTIs

E. coli (always most common)

enterococcus spp.

k. pneumonia

Proteus spp.

What 5 things should you watch for in UTIs

Presence of bacteria… AT ALL

Pyuria (WBCs)… should always be less than 5. Pyuria is considered when WBCs are >10 in the urine

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nitrites

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RBCs (should normally be

What is the difference between sensitivity and specificity?

Sensitivity: proportion of tests that read positive that are actually positive patients

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Specificity: proportion of tests that are read negative that are actually negative patients

What are the 3 main drugs we used to treat uncomplicated UTI’s, Dose, duration, and pearls

Nitrofurantoin 100 mg BID for 5 days -- only for patients with a lower UTI

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Bactrim 800/160 mg BID for 3 days -- sulfa allergies

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Fosfomycin 3 grams for 1 dose -- covers GNRs, ESBL, VRE

Treating complicated UTI’s, Durations, and pearls

Levofloxacin, ciprofloxacin, ceftriaxone - 7-10 days

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3rd or 4th generation cephalosporins - 7-14 days - ORAL option: cefdinir

Treatment for Catheter associated UTI’s

* old catheter of 2+ weeks
* if symptoms resolve when can treatment stop at the earliest? but they may last up to?
* What if we’re using fluoroquinolones?

Old catheters should be removed or replaced.

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7 day treatments may be enough if symptoms resolve but can go as long as 14 days

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Fluoroquinolone regimens can go only 3-5 days

What are the differences between the following terms:

* Neuropathy
* Impaired microvascular circulation
* Immunological defects

* Neuropathy - decreased feeling in a limb that can cause improper wound care
* Impaired microvascular circulation - causing impaired healing and antibiotic distribution to infected areas
* Immunological defects

What most commonly cause diabetic foot infections?

Gram-positive staphylococcus

When considering diabetic foot infections what diagnostic tests should be done?

Do cultures from deep tissues after wound is cleanset/debrided and BEFORE antibiotics

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X-ray should also be done to rule out osteomyelitis

In treating Diabetic foot infections, what is the go to and what needs to be closely monitored?

IV antibiotics are the GO TO treatment course and glycemic control is incredibly important

What drugs traditionally cover MRSA and which are considered Oral?

Doxy, bactrim, clindamycin, linezolid, Vanco, dapto, ceftaroline

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Orals: Doxy, bactrim, clindamycin, linezolid

What drugs traditionally cover pseudomonas?

Zosyn, cefepime, carbapenems, cipro, levo

What drugs traditionally cover anaerobes?

Zosyn, augmentin, Unasyn, carbapenems, metronidazole

Mild-moderate diabetic infection without recent antibiotic use?

B-lactam allergy?

MRSA suspected?

1. cephalexin or dicloxacillin
2. Clindamycin or a fluoroquinolone
3. Doxycycline or Bactrim

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What type of symptoms suggest the presence of anaerobes?

foul odor, necrosis, gas, or significant ischemia

Severe diabetic foot infection… the CLASSIC FUCKIN GO TO DUO:

\-minor penicillin allergy:

\-severe penicillin allergy or ESBL infections

Vanco and Zosyn

Vanco, cefepime, and metronidazole

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vanco + meropenem

How long should you treat a diabetic foot infection that is:

Mild-moderate?

Extensive, slow healing infections?

Osteomyelitis?

1-2 weeks

3-4 weeks

4-6 weeks

How do we define acute and chronic osteomyelitis?

Acute: days-weeks

Chronic: Months-years

What are the two ways that osteomyelitis begins

bacteremia spread from the blood into the bone

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spreads from nearby soft tissue/joints or from bone exposure to environment

What is the primary pathogen that can cause osteomyelitis?

Staphylococcus

Clinical presentation of osteomyelitis:

Acute:

Chronic

pain, redness, and edema

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acute: fever, systemic signs of infection

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Chronic: bone necrosis, non-healing ulcers or fractures, and sinus tracts from skin to bone

What is the preferred method of imaging a bone that is suspected to have osteomyelitis

MRI is preferred due to high sensitivity

When using antibiotics to treat osteomyelitis what should absolutely be targetted?

MRSA and GNRs

Examples: Vanco + ceftriaxone

Doxy+Cefdinir

What drugs are generally good at penetrating the bone?

Clindamycin, tetracyclines, fluoroquinolones, linezolid, trimethoprim

Generally how long do we treat osteomyelitis?

4-6 weeks

How do fluoroquinolones work?

bactericidal and inhibit DNA gyrase and topoisomerase 4

What is the benefit of a 6-F group on the CARBOXY-4-PYRIDONE structure?

increases lipophilicity and improves penetration of the bacterial cell wall

What is the relationship of Levofloxacin and Ofloxacin?

They are enantiomers of each other.

How is Ofloxacin prepared compared to its enantiomer levofloxacin?

Ofloxacin is sold as a racemic mixture

Levo is the 1S enantiomer only.

Which is stronger Levo or ofloxacin?

Levo is twice as active and 128 times more active than the R-enantiomer

Describe the fluoroquinolone SAR

A piperazine ring is present at C-7 that increases binding to CNS GABA receptors causing side effects

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An alkyl group on the piperazine ring decreases GABA binding.

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A cyclopropyl group on N-1 broadens the activity of the quinolone to include atypical bacteria

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Addition of a methoxy group on C-8 decreases the photosensitivity

What is mandatory for fluoroquinolone activity to occur?

The carboxy-4-pyridone pharmacophore is essential for activity

What does a fluoro group at C-6 of a fluoroquinolone do to activity?

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What if we add another at c-8?

It increases activity by increasing the lipophilicity of the molecule. the C-6 F group also increases DNA gyrase/topo 4 inhibition

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It improves drug absorption and half-life but ALSO increases drug-induced photosensitivity

Why should Fluoroquinolones NEVER be taken with any form of polyvalent metal ions

They can chelate with the C3-carboxylic acid and 4-keto group drastically decreasing their absorption and solubility

Tetracyclines must has a C6 hydroxyl group or else what?

They will not undergo dehydration and be destroyed