Comparative study of treatment with penicillin, ceftriaxone, trovafloxacin, quinupristin-dalfopristin and vancomycin in experimental endocarditis due to penicillin- and ceftriaxone-resistant Streptococcus pneumoniae

Pharmacodynamic analysis of ceftriaxone, gatifloxacin,and levofloxacin against Streptococcus pneumoniae with the use of Monte Carlo simulation

STUDY OBJECTIVE

To evaluate the pharmacodynamics of four intravenous antimicrobial regimens-ceftriaxone 1 g, gatifloxacin 400 mg, levofloxacin 500 mg, and levofloxacin 750 mg, each every 24 hours-against recent Streptococcus pneumoniae isolates.

DESIGN

Pharmacodynamic analysis using Monte Carlo simulation.

DATA SOURCE

The Surveillance Network (TSN) 2002 database.

MEASUREMENTS AND MAIN RESULTS

Streptococcus pneumoniae isolates (7866 isolates) were stratified according to penicillin susceptibilities as follows: susceptible (4593), intermediate (1986), and resistant (1287). Risk analysis software was used to simulate 10,000 patients by integrating published pharmacokinetic parameters, their variability, and minimum inhibitory concentration (MIC) distributions from the TSN database. Probability of target attainment was determined for percentage of time above the MIC (%T > MIC) from 0-100% for ceftriaxone and area under the concentration-time curve (AUC):MIC ratio from 0-150 for the fluoroquinolones. For ceftriaxone, probability of target attainment remained 90% or greater against the three isolate groups until a %T > MIC of 70% or greater, and it remained 90% or greater against susceptible and intermediate isolates over the entire interval (%T > MIC 0-100%). For levofloxacin 500 mg, probability of target attainment was 90% at an AUC:MIC < or = 30, but the curve declined sharply with further increases in pharmacodynamic target. Levofloxacin 750 mg achieved a probability of target attainment of 99% at an AUC:MIC ratio < or = 30; the probability remained approximately 90% until a target of 70 or greater, when it declined steeply. Gatifloxacin demonstrated a high probability (99%) of target attainment at an AUC:MIC ratio < or = 30, and it remained above 90% until a target of 70.

CONCLUSION

Ceftriaxone maintained high probability of target attainment over a broad range of pharmacodynamic targets regardless of penicillin susceptibility (%T > MIC 0-60%). Levofloxacin 500 mg maintained high probability of target attainment for AUC:MIC ratios 0-30; whereas, levofloxacin 750 mg and gatifloxacin maintained high probability of target attainment for AUC:MIC ratios 0-60. Rate of decline in the pharmacodynamic curve was most pronounced for the two levofloxacin regimens and more gradual for gatifloxacin and ceftriaxone.

Influência da abordagem cirúrgica (videolaparoscopia versus laparotomia) na gestação de coelhas prenhes

OBJETIVO: Estudar a influência de duas abordagens cirúrgicas na gestação de coelhas. MÉTODOS: Sessenta coelhas prenhes, divididas em três grupos: controle (C), laparotomia(L) e videolaparoscopia (V) foram observadas durante a evolução de suas gestações (duração da gestação, mortalidade fetal e peso dos láparos).Amostras sangüínea foram colhidas para análise laboratorial. RESULTADOS: A duração da gestação (31,6 ± 0,99 vs. 31,8 ± 1,8 vs. 31,3 ± 2,24 dias), a mortalidade fetal (1,0 ± 2,5 vs. 1,9 ± 2,7 vs. 1,4 ± 2,0 láparos) e o peso dos láparos vivos no primeiro dia de vida (48,7 ± 11,3 vs. 51,5 ± 11,9 vs. 48,3 ± 8,2 g) nos grupos C, L e V, respectivamente, não apresentaram diferenças estatísticas significativas (p>0,05). Nas análises sangüíneas (pré e pós) dos grupos L e V, observou-se diferença estatística (p>0,05) em relação às medidas do hematócrito (34,4 ± 3,1 e 33,1 ± 2,8 vs. 34,2 ± 3,2 e 30,3 ± 3,7 g/dl), do pH (7,4 ± 0,1 e 7,4 ± 0,1 vs. 7,5 ± 0 e 7,3 ± 0,1), do paCO2 ( 30,8 ± 5,1 e 40,7 ± 8,2 vs. 32 ± 3,7 e 53,5 ± 18,4). CONCLUSÃO: A videolaparoscopia é um procedimento seguro no período gestacional de coelhas.

Special issues in the management of infective endocarditis caused by gram-positive cocci

Gram-positive cocci, mainly streptococci and staphylococci, continue to cause the majority of cases of infective endocarditis. Among the streptococci causing IE, the long-standing predominance of oral or viridans-group streptococci has progressively faded, while the number of cases caused by "enteric streptococci" (Streptococcus bovis and enterococci) has increased. While most oral streptococci and S. bovis strains remain fully sensitive to penicillin, nutritionally variant streptococci--now renamed Abiotrophia--and enterococci can exhibit resistance to penicillin and/or glycopeptides that makes endocarditis more difficult to treat. Among the staphylococci causing endocarditis, the increasing proportion of coagulase-negative and methicillin-resistant strains observed in recent years has changed the approach to choice of antibiotic therapy. The purpose of this paper is to focus on some new aspects of the management of antibiotic therapy of IE due to streptococci and staphylococci, including recent developments such as once-daily aminoglycoside administration in IE, outpatient antibiotic therapy, and the evaluation of new antibiotics.