Skin/Soft tissue infections

True or false: vast majority of SSTIs are not gram-negative

true

what are the exceptions of gram-negative SSTIs?

• surgical wound infections

• animal bites

Describe the updated FDA regulations for ABSSSI (must be one of the following)

1. cellulitis/erysipelas

2. wound infections

3. major cutaneous abscess

4. must possess a min lesion size of 75cm² (small cellphone screen)

What is strongly recommended but NOT required for impetigo/ecthyma?

• gram stain

• culture

For impetigo, bullous and non-bullous lesions may be treated ____ or ____

orally; topically

Ecthyma should be treated (topically/orally)?

orally

What is the common treatment for impetigo/ecthyma?

topical mupirocin or retapamulin BID x 7 days

oral therapy for strep species and MSSA

MRSA agents when confirmed

What is the main way to go about managing SSTIs?

1. non-purulent (mild-severe)

2. purulent (mild-severe)

Purulent SSTI management strategy

• incision and drainage

• gram stain and culture recommended

• antibiotics w/ MRSA coverage appropriate if:

  • failed I and D and oral antibiotics

  • SIRS criteria

  • immunocompromised

Non-purulent SSTI management strategy (cellulitis/erysipelas)

• anti-streptococcal agent ± anti-staphylococcal coverage

• cephalexin (initial option)

• clindamycin (for allergic patients)

• empiric piperacillin/tazobactam + vanc if:

  • failed I and D and oral antibiotics

  • SIRS criteria

  • immunocompromised

True or false: for non-purulent SSTIs (cellulitis/erysipelas), you need MRSA coverage

false

What makes community-associated MRSA different from healthcare-associated?

• manifests as SSTI

• more virulent

• generally susceptible to more antibiotics

Who is susceptible to CA-MRSA?

• frequent contact or crowding

• sports

• students

• jails

Treatment of CA-MRSA SSTIs

• Surgical drainage is key

• I and D are required for 80% ED patients with purulent

• many cured with I and D alone

What agents cover MRSA in SSTI? (oral)

• SMX/TMP

• clindamycin

• doxycycline

• minocycline

What agents cover MRSA in SSTI? (IV)

• vancomycin

• daptomycin

• linezolid

Clindamycin is a good option for ______ patients

pediatric

What is the usual dosage for clindamycin

• 600-900mg IV q6-8h

• 300mg-450mg PO q6h

Clindamycin has excellent coverage for _____ and _____

staph; strep

Clindamycin suppresses _____ toxin production and other endotoxins

PVL

For clindamycin, an in-vitro susceptibility must be confirmed with a _______ test

D

Usual dosage for bactrim

1-2 tabs BID for adults

8-10 mg/kg/d of trimethoprim

Bactrim has poor activity against ______

streptococci

ADR of bactrim

• rash

• hyperkalemia

• severe interaction with warfarin

• bone marrow suppression

• nephrotoxicity

  • lab intx with SCr more common

• avoid in late term or 1st trimester

Tetracyclines are NOT recommended for children <_____ years old

8

Tetracyclines have a lack of activity against group ___ streptococcus

A

Usual dose for tetracyclines

100mg PO BID

ADR of tetracyclines

• GI toxicity (N/V and pill esophagitis)

• neurotoxicity (minocycline)

• phototoxicity

Clinical pearls of vanc

• increased failures with MIC >1.5

• renal dose adjustments (80-90% renally cleared)

• oral for C.diff

ADR of vanc

• ototoxicity (peaks)

• nephrotoxicity (troughs in combo with other nephrotoxic agents)

• red man syndrome

Linezolid binds to the (30/50) S ribosomal subunit?

50

Dosing for vanc is based on?

• trough

• AUC

• HD

Dosing for linezolid

600mg IV/PO BID x 5-14 days

100% bioavailability

ADR of linezolid

• monitor CBC weekly!

• irreversible peripheral neuropathy

• bone marrow suppression (2 weeks after therapy)

• well tolerated overall

Clinical pearl of linezolid

• weak MAO-I activity

• serotonin syndrome

• monitor BP

Dosing for daptomycin

4-6mg/kg IV daily x 5-14 days for SSTIs

ADR of daptomycin

• rhabdomyolysis

• monitor CPKs and muscle symptoms weekly

Clinical pearl of daptomycin

renally dose adjusted

What are some of the newer therapies?

• tedizolid

• dalbavancin

• oritavancin

• omadacycline

• delafloxacin

Clinical pearls of tedizolid

• prodrug converted to active that binds 50S

• FDA approved for SSTI for 6 day course

• noninferior to linezolid

• 600mg IV or PO QD

• weak MAO-A and B inhibitor

• well tolerated with some GI, CNS, BMS

Clinical pearls of dalbavancin

• for complicated SSTIs

• 1-2 dose regimens

• N/D and HA

• off label use for bloodstream infections

• terminal ½ life is >2 weeks

One dose regimen for dalbavancin

1500mg IV over 30 minutes

Clinical pearls of oritavancin

• not for osteomyelitis

• complicated SSTIs

• 1200mg IV once weekly (3 or 1 hour infusion)

• well tolerated

• long half life

Interactions with oritavancin

• increases warfarin concentrations

• interferes with PT/INR and aPTT

• not dialyzable

Clinical pearls of omadacycline

• binds 30S

• SSTIs and pneumonia

• IV and PO dosing with loading dose

• N/V, infusion rxn

  • no renal dose adjustments

Clinical pearls of delafloxacin

• SSTIs and pneumonia

• IV and PO dosing for 5-14 days

• NVD, HA

• elevated LFTs

• renally dose adjusted

What is the BBW for delafloxacin?

tendonitis, tendon rupture and CNS effects (exacerbation of myasthenia gravis)

When do you use preemptive antibiotics for 3-5 days with animal and human bite prevention?

• immunocompromised

• asplenic

• severe liver diseases

• significant edema

• moderate/severe injuries to hand/face

• joint/periosteum penetrates

Treatment for purulent wounds with animal bite infections

• amoxicillin/clavulanate (DOC)

• cephalosporin + metronidazole/clindamycin

• moxifloxacin or doxy

Purulent wounds from animal bites are often polymicrobial including which anaerobes?

• streptococci

• staphylococci

• pasturella species

This is the primary cause of abscesses

MRSA