Table 1. In Vitro Susceptibilities Cardiobacterium hominisa
|
|||||
Antimicrobial agent |
n |
Representative MIC (µg/ml)b
|
Breakpointc |
n (%) susceptible |
|
Penicillin |
22 |
0.05 |
|
22 (100%) |
|
Ampicillin |
16 |
<0.4 |
|
15 (94%) |
|
Oxacillin |
3 |
NAd |
|
2 (67%) |
|
Carbenicillin |
5 |
<1.6 |
£16 |
4(100%) |
|
Cephalothin |
11 |
<0.4 |
£8 |
11 (100%) |
|
Chloramphenicol |
17 |
1.25 |
£8 |
17 (100%) |
|
Colistin |
2 |
NA |
|
2 (100%) |
|
Trimethoprim-sulphamethoxazole
|
3 |
NA |
£2/38 |
2 (100%) |
|
Sulfonamide |
1 |
NA |
|
0 (0%) |
|
Tetracycline |
19 |
0.25 |
£4 |
19 (100%) |
|
Erythromycin |
14 |
NA |
£0.5 |
11 (79%) |
|
Gentamicin |
9 |
<0.8 |
£4 |
8 (89%) |
|
Kanamycin |
6 |
<0.8 |
£16 |
1 (17%) |
|
Streptomycin |
14 |
1.6 |
|
14 (100%) |
|
Tobramycin |
2 |
NA |
£4 |
2 (100%) |
|
Rifampin |
1 |
NA |
£1 |
1 (100%) |
|
Vancomycin |
3 |
25 |
£4 |
1 (33%) |
|
Clindamycin |
2 |
5 |
£0.5 |
0 (0%) |
|
a Modified from Wormser GP, Bottone EJ. Cardiobacterium hominis: review of microbiological and clinical features. Rev Infect Dis 1983; 5:680-691.
b MIC50, MIC90 and MIC Range not reported.
c NCCLS interpretive standards for susceptibility (µg/ml) (52).
d NA = Data not available
Table 2: In Vitro Susceptibility Testing of HACEK Organismsa
|
Susceptible (µg/ml) |
Intemediate (µg/ml) |
Resistant (µg/ml) |
Ampicillin |
<1 |
2 |
>4 |
Ampicillin/sulbactam |
<2/1 |
- |
>4/2 |
Amoxycllin/clavulanic acid |
<4/1 |
- |
>8/2 |
Penicillin |
<1 |
3 |
>4 |
Ceftriaxone / Cefotaxime |
<2 |
- |
- |
Imipenem/meropenem b |
<0.5 |
1 |
>2 |
a Clinical and Laboratory Standards Institute. Methods for antimicrobial dilution and disk susceptibility testing of infrequently isolated or fastidious bacteria. Approved standard M45-A. Wayne, PA: Clinical and Laboratory Standards Institute 2006.
b unless Haemophilus spp. isolates; susceptible: 4 µg/ml, intermediate: 8 µg/ml, resistant: 16 µg/ml
Table 3: Therapy for Both Native and Prosthetic Valve Endocarditis Caused by HACEK Microorganismsa
Regimen |
Dosage and route |
Native valve Duration, wk |
Prosthetic valve Duration, wk |
Comments |
Ceftriaxone |
2g/24h IV/IM in 1 dose |
4 |
6 |
Cefotaxime or another third or fourth generation cephalosporin may be substituted |
or |
|
|
|
|
Ampicillin-sulbactam |
|
4 |
6 |
|
or |
|
|
|
|
Ciprofloxacin
|
1000mg/24h PO or 800mg/24 IV in 2 equally divided doses |
4 |
6 |
Only for patients unable to tolerate cephalosporin and ampicillin therapy Levofloxacin, gatifloxacin or moxifloxacin may be substituted. Fluoroquinolones not generally recommended for patients <18 y old. |
a Modified from Baddour L, Wilson W, Bayer A et al. Infective endocarditis: diagnosis, antimicrobial therapy, and
management of complication: a statement for healthcare professionals from the Committee on Rheumatic Fever,
Endocarditis and Kawasaki Disease, Council on Cardiovascular Disease in the Young and the Councils on Clinical
Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association: endorsed by the Infectious
Diseases Society of America. Circ 2005; 111: e394-434.