1370. Role of Clindamycin Versus Linezolid for Serious Group A Streptococcal Infections

Abstract Background Streptococcus pyogenes can cause severe illnesses such as toxic-shock syndrome and necrotizing fasciitis due to pyrogenic exotoxins. Clindamycin is added to penicillin for treatment of severe S. pyogenes infections as it is a bacterial protein synthesis inhibitor which reduces toxin production. However, clindamycin is associated with several adverse effects including C. difficile infection. Linezolid is a bacterial protein synthesis inhibitor that has been shown to provide excellent coverage of S. pyogenes including toxin inhibition in vitro, but clinical evidence is lacking. We compared outcomes of patients treated with linezolid versus clindamycin for serious S. pyogenes infections. Methods This was a retrospective study of patients with necrotizing fasciitis or toxic shock syndrome caused by S. pyogenes admitted to the Shock Trauma Center at University of Maryland Medical Center treated with at least 48 hours of either clindamycin or linezolid. Data collected included Sequential Organ Failure Assessment (SOFA) and Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) severity scores, time to resolution of infection, number of surgeries, C. difficile infection, other antibiotic associated adverse effects, and mortality. Associations between patient characteristics, antibiotic groups, and outcomes were analyzed using the chi-square test, Fisher’s exact test and t-test or Wilcoxon rank-sum test as appropriate (SAS v 9.4). Results 52 patients were included, 26 treated with clindamycin and 26 with linezolid. Most patients (85% clindamycin and 96.2% linezolid) were treated for necrotizing fasciitis. Baseline characteristics, including SOFA and LRINEC scores, were similar between the groups. There was no difference in mortality between patients treated with clindamycin versus linezolid (11.5% vs. 7.7%, p = 0.22), and resolution of infection was similar between the groups (92.3% vs. 88.5%, p = 1.0). There was no difference in adverse effects between the clindamycin and linezolid groups, including C. difficile infection (3.9% vs. 0% p = 1.0) and thrombocytopenia (30.8% vs. 42.3%, p = 0.4). Conclusion Linezolid could be an alternate to clindamycin for the treatment of serious toxin producing S. pyogenes infections. Further prospective studies are needed. Disclosures Emily Heil, PharmD, MS, BCIDP, Nothing to disclose

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Evidence for Different Contributions of Archaea and Bacteria to the Ammonia-Oxidizing Potential of Diverse Oregon Soils

Applied and Environmental Microbiology ◽

10.1128/aem.01324-10 ◽

2010 ◽

Vol 76 (23) ◽

pp. 7691-7698 ◽

Cited By ~ 93

Author(s):

Anne E. Taylor ◽

Lydia H. Zeglin ◽

Sandra Dooley ◽

David D. Myrold ◽

Peter J. Bottomley

Keyword(s):

Protein Synthesis ◽

Protein Synthesis Inhibitor ◽

Ammonia Oxidizing Bacteria ◽

Ammonia Monooxygenase ◽

Bacterial Protein ◽

Protein Synthesis Inhibitors ◽

Synthesis Inhibitor ◽

Ammonia Oxidizing Archaea ◽

Pasture Soil ◽

Bacterial Protein Synthesis

ABSTRACT A method was developed to determine the contributions of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) to the nitrification potentials (NPs) of soils taken from forest, pasture, cropped, and fallowed (19 years) lands. Soil slurries were exposed to acetylene to irreversibly inactivate ammonia monooxygenase, and upon the removal of acetylene, the recovery of nitrification potential (RNP) was monitored in the presence and absence of bacterial or eukaryotic protein synthesis inhibitors. For unknown reasons, and despite measureable NPs, RNP did not occur consistently in forest soil samples; however, pasture, cropped, and fallowed soil RNPs commenced after lags that ranged from 12 to 30 h after acetylene removal. Cropped soil RNP was completely prevented by the bacterial protein synthesis inhibitor kanamycin (800 μg/ml), whereas a combination of kanamycin plus gentamicin (800 μg/ml each) only partially prevented the RNP (60%) of fallowed soils. Pasture soil RNP was completely insensitive to either kanamycin, gentamicin, or a combination of the two. Unlike cropped soil, pasture and fallowed soil RNPs occurred at both 30Ã¯Â¿Â½C and 40Ã¯Â¿Â½C and without supplemental NH4 + (≤10 μM NH4 + in solution), and pasture soil RNP demonstrated ∼50% insensitivity to 100 μM allyl thiourea (ATU). In addition, fallowed and pasture soil RNPs were insensitive to the fungal inhibitors nystatin and azoxystrobin. This combination of properties suggests that neither fungi nor AOB contributed to pasture soil RNP and that AOA were responsible for the RNP of the pasture soils. Both AOA and AOB may contribute to RNP in fallowed soil, while RNP in cropped soils was dominated by AOB.

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