Warren S. Joseph, DPM, FIDSARoxborough Memorial Hospital, Phila.,

PAwww.leinfections.com

Deep soft tissue & Bone cultures grew MSSA & Group B Streptococcus

Patient initially on Vanco + pip/tazo Given these bugs…what drug do you

choose? Cephalexin

A marked decrease in patients presenting with MRSA

An increase in ESBL/KPC caused DFI The approval and release of

ceftaroline The revised IDSA DFI Guidelines

“Aerobic gram-positive cocci (especially Staphylococcus aureus) are the predominant pathogens in diabetic foot infections. Patients who have chronic wounds or who have recently received antibiotic therapy may also be infected with gram-negative rods, and those with ischemia or gangrene may have obligate anaerobes.” CID Oct 1, 2004

Anti-Staph and Strep Anti-Staph and Strep antibioticantibiotic

May be true in mild infection but no definitive data

Polymicrobial flora may worsen prognosis

Caution in severe infection and in osteomyelitis

Staphylococcus Staphylococcus aureusaureus

Beta-haemolytic Beta-haemolytic StrepStrep

EnterobacteriaceaeEnterobacteriaceae

AnaerobesAnaerobes

Commensal gram-positive cocciCommensal gram-positive cocci

Slide Courtesy of A. Berendt, MD

IDSA Mild (po) ASOC Amoxicillin/clavulanic acid Clindamycin Oral PRPModerate/Severe Β-lactam/β-lactamase inhibitor compound Ertapenem Cefazolin Clindamycin (IV/PO) Vancomycin

NEJM Jan 2009

THE ROLE OF HANDWASHING IN THE SPREAD of MRSA

Mild Later generation tetracycline (PO)

• Minocycline• Doxycycline

TMP/SMX Clindamycin (+/-)Moderate/Severe Linezolid (IV/PO) Vancomycin (IV) Daptomycin (IV) Tigecycline (IV) Ceftaroline (IV)

An increasing clinical problem “Staph aureus with reduced

susceptibility to vancomycin” aka “MIC Creep”

• Difficult to detect • MIC on the rise from 0.5 » 1.0 » 2.0 µg• Have been associated with Tx failures

PLEASE – Look at your vancomycin MIC if considering its use against MRSA!

0

10

20

30

40

50

60

70

80

90

2000 2001 2002 2003 2004

MIC ≤0.5 MIC=1 MIC ≥2

Wang G et al. J Clin Microbiol. 2006;44:3883-3886.

% o

f Is

ola

tes

79.9

19.9

0.2 0.2 0.3 0.2 0.8

80.9

18.9

64.6

35.1

60.1

39.7

70.4

28.8

MIC=minimum inhibitory concentration.

“If you show a vancomycin MIC against MRSA of >1µg/ml you can not achieve a level of vancomycin that is high enough to be both safe and effective. You should use an alternative agent”

paraphrasing Robert Moellering, MD, ICAAC 2009

Courtesy of Lee Rogers, DPM

This one is easy…pretty much anything you use for Staphylococcus will be active against Group B Streptococcus

Extended Spectrum β-lactamases (ESBL)• Increasing in E. coli, Proteus mirablis & Kleb

pneumo along with other gnr• Resistant to most penicillins, cephalosporins

and β lactamase inhibitor compounds• Still susceptible to most carbapenems and tigecycline

Carbapenemase producing gnr (KPC)• Not yet as common as ESBL• As name implies, resistant to carbapenems

NDM-1 Do we need to concern ourselves??

Do we really need to treat it?Options Ciprofloxacin (PO/IV) Ceftazidime (IV) Cefepime (IV) Aztreonam (IV)

+/- Aminoglycoside Other quinolone Piperacillin/tazobactam *

“Head of the Snake” principle Consider empiric “De-escalation”

therapy depending on local MRSA prevalence

Watch your vancomycin MICs for “creep”

Be aware of ESBLs and KPCs in your hospital (speak with your IC specialist)

Be alert for “Pseudomonophobia”