Viridans-Group Streptococci
Background
- A Gram Positive Bacteria in the Streptococcus Genus
- In general, low virulence pathogens and likely Blood Culture Contaminant unless risk factor (21-50% of positive blood cultures are clinically significant)[1]
Types
- Streptococcus milleri
- Streptococcus sanguis
- Streptococcus mitis
- Streptococcus bovis
Risk Factors for Viridans Bacteremia[2]
- neutropenia
- oral mucositis
- irradiation to the oral cavity
- antibiotic prophylaxis with trimethoprim-sulfamethoxazole or fluoroquinolones
- intravenous hyperalimentation
- high dose chemotherapy
Antibiotic Sensitivities[3]
Category | Antibiotic | Viridans strep |
Penicillins | Penicillin G | I |
Penicillin V | I | |
Methicillin | I | |
Nafcillin/Oxacillin | I | |
Cloxacillin/Diclox. | I | |
Amino-Penicillins | AMP/Amox | I |
Amox-Clav | I | |
AMP-Sulb | I | |
Anti-Pseudomonal Penicillins | Ticarcillin | I |
Ticar-Clav | I | |
Pip-Tazo | I | |
Piperacillin | I | |
Carbapenems | Doripenem | S |
Ertapenem | S | |
Imipenem | S | |
Meropenem | S | |
Aztreonam | R | |
Fluroquinolones | Ciprofloxacin | R |
Ofloxacin | R | |
Pefloxacin | X1 | |
Levofloxacin | S | |
Moxifloxacin | S | |
Gemifloxacin | S | |
Gatifloxacin | S | |
1st G Cephalo | Cefazolin | S |
2nd G. Cephalo | Cefotetan | S |
Cefoxitin | S | |
Cefuroxime | S | |
3rd/4th G. Cephalo | Cefotaxime | S |
Cefizoxime | S | |
CefTRIAXone | S | |
Ceftaroline | S | |
CefTAZidime | I | |
Cefepime | S | |
Oral 1st G. Cephalo | Cefadroxil | S |
Cephalexin | S | |
Oral 2nd G. Cephalo | Cefaclor/Loracarbef | S |
Cefproxil | R | |
Cefuroxime axetil | S | |
Oral 3rd G. Cephalo | Cefixime | S |
Ceftibuten | R | |
Cefpodox/Cefdinir/Cefditoren | S | |
Aminoglycosides | Gentamicin | X1 |
Tobramycin | X1 | |
Amikacin | X1 | |
Chloramphenicol | X1 | |
Clindamycin | X1 | |
Macrolides | Erythromycin | X1 |
Azithromycin | X1 | |
Clarithromycin | X1 | |
Ketolide | Telithromycin | X1 |
Tetracyclines | Doxycycline | X1 |
Minocycline | X1 | |
Glycylcycline | Tigecycline | X1 |
Daptomycin | X1 | |
Glyco/Lipoclycopeptides | Vancomycin | X1 |
Teicoplanin | X1 | |
Telavancin | X1 | |
Fusidic Acid | X1 | |
Trimethoprim | X1 | |
TMP-SMX | X1 | |
Urinary Agents | Nitrofurantoin | X1 |
Fosfomycin | X1 | |
Other | Rifampin | X1 |
Metronidazole | X1 | |
Quinupristin dalfoppristin | X1 | |
Linezolid | X1 | |
Colistimethate | X1 |
Key
- S susceptible/sensitive (usually)
- I intermediate (variably susceptible/resistant)
- R resistant (or not effective clinically)
- S+ synergistic with cell wall antibiotics
- U sensitive for UTI only (non systemic infection)
- X1 no data
- X2 active in vitro, but not used clinically
- X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
- X4 active in vitro, but not clinically effective for strep pneumonia
Table Overview
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See Also
References
- ↑ Antibiotic Therapy for Positive Blood Cultures. Perez-Jorge EV, et al. Antimicrobe. http://www.antimicrobe.org/new/e38rev2.asp
- ↑ Antibiotic Therapy for Positive Blood Cultures. Perez-Jorge EV, et al. Antimicrobe. http://www.antimicrobe.org/new/e38rev2.asp
- ↑ Sanford Guide to Antimicrobial Therapy 2014