University of Pennsylvania Medical Center Guidelines for Antibiotic Use

Antimicrobial Susceptibilities of Obligately Anaerobic Bacteria Performed 12/08 to 2/09 on Bacterial Isolates Collected from 2007 to 2008

% Susceptible - Etest, CLSI M11-A4 guidelines

Bacterium No. Tested Pen G A/C Mero Metro Clinda Vanco
 Breakpoint    <1 <8/4 <8 <16 <4 <2
B. fragilis group 49 NT* 98** 98** 100 47 NT*
Clostridium 18 89*** 100 no data 94 50 no data
Gram-pos cocci (Peptostreptococcus, Finegoldia) 23 100 100 no data NT* 78 100
Pigmented Gram-neg rods (Prevotella, Porphyromonas)

3

2006 data

NT* 3^ no data 3^ 2^ NT*
Fusobacterium 3 2^ 3^ no data 3^   NT
P. acnes 38 100 no data no data NT* 97** 100
Veillonella 8 3^ 8^ no data 8^ 6^ NT*

Pen G - Penicillin G, A/C - Amoxicillin/clavulanate, Mero - Meropenem, Metro - Metronidazole, Clinda - Clindamycin, NT - not tested,

* - NT= resistance common to this drug for this bacterium and drug not tested; *** the penicillin MICs of 2 C. tertium isolates was 1 mg/L, and would likely respond to high dosage penicillin therapy.

^ no of isolates rather than % are reported because of low N

**Note that both meropenem and amoxicillin/clavulanate resistance occurs in B. fragilis, though at low frequency. Also note that clindamycin resistance occurs at low frequency in P. acnes. Anaerobic susceptibility testing is available on request, and may be useful in difficult therapeutic circumstances, such as undrained abscesses, drug allergies and intolerance.

updated 2/24/09 P. Edelstein

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