RESUMO
Streptococcus pneumoniae is an important cause of acute otitis media (AOM). The aim of this study was to evaluate trends in antibiotic resistance and circulating serotypes of pneumococci isolated from middle ear fluid of French children with AOM during the period 2001-2011, before and after the introduction of the PCV-7 (2003) and PCV-13 (2010) vaccines. Between 2001 and 2011 the French pneumococcal surveillance network analysed the antibiotic susceptibility of 6683 S. pneumoniae isolated from children with AOM, of which 1569 were serotyped. We observed a significant overall increase in antibiotic susceptibility. Respective resistance (I+R) rates in 2001 and 2011 were 76.9% and 57.3% for penicillin, 43.0% and 29.8% for amoxicillin, and 28.6% and 13.0% for cefotaxime. We also found a marked reduction in vaccine serotypes after PCV-7 implementation, from 63.0% in 2001 to 13.2% in 2011, while the incidence of the additional six serotypes included in PCV-13 increased during the same period, with a particularly high proportion of 19A isolates. The proportion of some non-PCV-13 serotypes also increased between 2001 and 2011, especially 15A and 23A. Before PCV-7 implementation, most (70.8%) penicillin non-susceptible pneumococci belonged to PCV-7 serotypes, whereas in 2011, 56.8% of penicillin non-susceptible pneumococci belonged to serotype 19A. Between 2001 and 2011, antibiotic resistance among pneumococci responsible for AOM in France fell markedly, and PCV-7 serotypes were replaced by non-PCV-7 serotypes, especially 19A. We are continuing to assess the impact of PCV-13, introduced in France in 2010, on pneumococcal serotype circulation and antibiotic resistance.
Assuntos
Farmacorresistência Bacteriana , Otite Média/epidemiologia , Otite Média/microbiologia , Infecções Pneumocócicas/epidemiologia , Infecções Pneumocócicas/microbiologia , Streptococcus pneumoniae/efeitos dos fármacos , Antibacterianos/farmacologia , França/epidemiologia , Humanos , Incidência , Testes de Sensibilidade Microbiana , Otite Média com Derrame/microbiologia , Vacinas Pneumocócicas , SorogrupoAssuntos
Achromobacter denitrificans/efeitos dos fármacos , Antibacterianos/farmacologia , Piperacilina/farmacologia , Tobramicina/farmacologia , Achromobacter denitrificans/isolamento & purificação , Aminoglicosídeos/farmacologia , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana , Sinergismo Farmacológico , Técnicas In Vitro , Testes de Sensibilidade MicrobianaRESUMO
We compared the in vitro activity of dalfopristin and quinupristin combined with five intravenous antibiotics in a 3-dimensional model. We tested six strains of Staphylococcus aureus selected with different patterns of resistance to methicillin and erythromycin. Dalfopristin and quinupristin displayed a very synergistic activity against all the strains with a mean 16- or 32-fold decrease of inhibitory concentrations in combination. That synergy was even better against erythromycin-resistant strains. In combination with tigecycline or fosfomycin, the antibacterial activity could be consistently enhanced with the same decrease of inhibitory concentrations. A synergy was also observed, less regularly and at a lower level, with rifampin, gentamicin or vancomycin. Combinations of dalfopristin and quinupristin with tigecycline or fosfomycin could be very interesting in clinical practice because the inhibitory effect could be achieved with very low concentrations of each component, even when erythromycin-resistant strains are concerned.
Assuntos
Antibacterianos/administração & dosagem , Testes de Sensibilidade Microbiana/métodos , Staphylococcus aureus/efeitos dos fármacos , Virginiamicina/administração & dosagem , Quimioterapia Combinada , Fosfomicina/administração & dosagem , Gentamicinas/administração & dosagem , Técnicas In Vitro , Minociclina/administração & dosagem , Minociclina/análogos & derivados , Rifampina/administração & dosagem , Tigeciclina , Vancomicina/administração & dosagemRESUMO
Acute postoperative endophthalmitis caused by Staphylococcus lugdunensis is infrequently reported in clinical studies. Five cases of acute postcataract surgery endophthalmitis caused by S. lugdunensis were taken from a multicenter prospective study conducted in four university-affiliated hospitals in France (2004 to 2005). These cases were characterized by severe ocular inflammation occurring with a mean delay of 7.6 days after cataract surgery, severe visual loss (hand motions or less in three cases), and dense infiltration of the vitreous. Each of these patients was initially treated by using a standard protocol with intravitreal (vancomycin and ceftazidime), systemic, and topical antibiotics. Given the severity of the endophthalmitis, even though bacteria were sensitive to intravitreal antibiotics, pars plana vitrectomy was needed in four cases. The final visual prognosis was complicated by severe retinal detachment in three cases. The microbiological diagnosis was reached by using conventional cultures with specific biochemical tests and eubacterial PCR amplification followed by direct sequencing.
Assuntos
Extração de Catarata/efeitos adversos , Endoftalmite , Reação em Cadeia da Polimerase/métodos , Complicações Pós-Operatórias , Staphylococcus/isolamento & purificação , Doença Aguda , Idoso , Idoso de 80 Anos ou mais , Meios de Cultura , Endoftalmite/diagnóstico , Endoftalmite/tratamento farmacológico , Endoftalmite/microbiologia , Infecções Oculares Bacterianas/diagnóstico , Infecções Oculares Bacterianas/tratamento farmacológico , Infecções Oculares Bacterianas/microbiologia , Feminino , França , Hospitais Universitários , Humanos , Masculino , Pessoa de Meia-Idade , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus/classificação , Staphylococcus/genéticaRESUMO
Reported here are the microbiological and epidemiological details of a presumed outbreak of aerobic gram-negative bacilli infections affecting 19 hematological patients, which was traced to contaminated disinfectant. Over a 5-month period, the following organisms were isolated from the blood cultures of 19 neutropenic patients: Pseudomonas fluorescens (n = 13), Achromobacter xylosoxidans (n = 12), Comamonas testosteroni (n = 2) or Stenotrophomonas maltophilia (n = 1). The affected patients were all treated with an expensive regimen of broad-spectrum antibiotic therapy. The same bacteria were recovered from environmental samples as well as from the water pipes of an apparatus for dispensing disinfectant (didecyldimethylammonium chloride). Genotyping results indicated that many of the clinical strains were identical to strains isolated from the apparatus. It was eventually discovered that the night staff was in the habit of disinfecting the blood-culture bottles before use, thereby contaminating the bottles with bacteria contained in the disinfectant. Contamination of the apparatus resulted from faulty maintenance.
Assuntos
Bacteriemia/epidemiologia , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Desinfetantes , Contaminação de Medicamentos , Bactérias Aeróbias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/epidemiologia , Bacteriemia/etiologia , Bacteriemia/microbiologia , Infecção Hospitalar/etiologia , Surtos de Doenças , Embalagem de Medicamentos , Eletroforese em Gel de Campo Pulsado/métodos , Bactérias Aeróbias Gram-Negativas/crescimento & desenvolvimento , Infecções por Bactérias Gram-Negativas/etiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/microbiologia , Humanos , Abastecimento de ÁguaRESUMO
We have compared the interplay of several antimicrobial agents and aminoacids on the neutrophil respiratory burst in response to formylmethionyl-leucyl-phenylalanine (fMLP), a chemoattractant. Mainly, an inhibitory effect has been observed in the penicillin family of agents and an enhancing effect in the cephalosporin family of agents. The molecules in which the sulfur numbered 1 in the 6-APA or 7-ACA nucleus was replaced by a carbon or an oxygen, had a different effect as compared with the other members of the family. The modulatory effects of ampicillin and cephalothine were not significant at a concentration lower than 10 mg/l and the effect of cephalothine looked maximum at 20-40 mg/l. If studies in cell-free systems demonstrated that the inhibitory effect of some antimicrobials could be due to a direct oxidant-scavenger activity mainly of HOCl, only hypotheses are proposed to explain the enhancing activity of the others. It could be in relation with (i) a synergistic effect upon fMLP receptor leading to an increase in H(2)O(2)/HOCl production or (ii) the generation of new oxydant products originating in cephalosporin lysis under HOCl attack, which would be able to react with luminol. The interplay of antimicrobial agents with the respiratory burst measured outside the cells probably has no therapeutic consequences because the bactericidal activity of neutrophils is achieved inside phagosomes where few agents are known to come into and where chemical conditions are different. On the opposite, in clinical use, this interplay could be interesting to study for a prevention of side effects.
Assuntos
Antibacterianos/farmacologia , Neutrófilos/fisiologia , Explosão Respiratória/fisiologia , Aminoácidos/farmacologia , Humanos , Luminol , Neutrófilos/efeitos dos fármacos , Explosão Respiratória/efeitos dos fármacosAssuntos
Infecções Pneumocócicas/microbiologia , Sinusite/microbiologia , Adulto , Técnicas Bacteriológicas , Estudos Transversais , Resistência a Múltiplos Medicamentos , França , Humanos , Testes de Sensibilidade Microbiana , Infecções Pneumocócicas/tratamento farmacológico , Infecções Pneumocócicas/epidemiologia , Sinusite/tratamento farmacológico , Sinusite/epidemiologia , Streptococcus pneumoniae/efeitos dos fármacosRESUMO
TEM-89 (CMT-3) is the first complex mutant beta-lactamase produced by a clinical strain of Proteus mirabilis (strain Pm 631). This new enzyme, which has a pI of 6.28, is derived from TEM-3 and has a single amino acid substitution also encountered in TEM-59 (inhibitor-resistant TEM beta-lactamase IRT-17): Ser-130 to Gly. TEM-89 hydrolyzed penicillins to the same extent that TEM-3 did but lost almost all hydrolytic activity for cephalosporins and, like TEM-59, was highly resistant to inhibitors.
Assuntos
Infecções por Proteus/microbiologia , Proteus mirabilis/enzimologia , Proteus mirabilis/genética , beta-Lactamases/genética , beta-Lactamases/metabolismo , Substituição de Aminoácidos , Conjugação Genética , Escherichia coli/genética , Humanos , Focalização Isoelétrica , Cinética , Dados de Sequência Molecular , Mutação/genética , Plasmídeos/genética , Proteus mirabilis/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
The epidemiological study of several multidrug-resistant Enterobacteriaceae isolated from five patients demonstrated in vivo dissemination of a 100-kb plasmid encoding the extended-spectrum beta-lactamase TEM-24 from a clonal strain of Enterobacter aerogenes to different strains of Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Proteus mirabilis, and Serratia marcescens.
Assuntos
Proteínas de Bactérias , Enterobacteriaceae/efeitos dos fármacos , Transferência Genética Horizontal , Plasmídeos/genética , beta-Lactamases/genética , beta-Lactamas/farmacologia , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/genética , Resistência a Múltiplos Medicamentos/genética , Eletroforese em Gel de Campo Pulsado , Enterobacteriaceae/enzimologia , Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/microbiologia , Humanos , Testes de Sensibilidade MicrobianaRESUMO
RESISTANCE BY REGION: Resistance varied greatly by region, ranging from 34.2% resistant strains in Alsace to 63.1% in Brittany. The incidence of resistant strains was always higher in children (especially in children aged 1 to 5 years) and in ENT samples. The time course of resistance has varied between regions, as has that of serotypes. CRUCIAL FINDING: In these 6 regions, and despite a high incidence (that varied from one region to another) of reduced susceptibility strains for penicillin G, amoxicillin (19-32%) and cefotaxime (6.5-18.5%), amoxicillin-cefotaxime resistant strains remained very rare (0.2-3.5%).
Assuntos
Resistência Microbiana a Medicamentos , Infecções Pneumocócicas/epidemiologia , Infecções Pneumocócicas/microbiologia , Vigilância da População , Sistema de Registros , Distribuição por Idade , Criança , Pré-Escolar , França/epidemiologia , Humanos , Incidência , Lactente , Vigilância da População/métodos , Características de Residência , Sorotipagem , Streptococcus pneumoniae/classificação , Fatores de TempoRESUMO
TEM-56 produced by a Klebsiella pneumoniae clinical isolate is a novel beta-lactamase of isoelectric point 6.4 that confers a moderate resistance level to expanded-spectrum cephalosporins. The amino acid sequence deduced from the corresponding bla gene showed two amino acid replacements with respect to the TEM-2 sequence: Glu-104 to Lys and His-153 to Arg. This enzyme showed catalytic properties close to those of TEM-18. Thus, TEM-56 appears as a new TEM mutant, an intermediary between TEM-18 and the extended-spectrum beta-lactamase TEM-21.
Assuntos
Klebsiella pneumoniae/enzimologia , beta-Lactamases/metabolismo , Substituição de Aminoácidos , Humanos , Concentração Inibidora 50 , Cinética , Klebsiella pneumoniae/genética , Testes de Sensibilidade MicrobianaRESUMO
A strain of Salmonella virchow was isolated in the myocardium of a 1 1/2 month child who died suddenly. The source of contamination was the water of a family aquarium containing turtles.
Assuntos
Miocardite/microbiologia , Infecções por Salmonella/etiologia , Morte Súbita do Lactente/etiologia , Humanos , Lactente , Masculino , Salmonella/isolamento & purificaçãoRESUMO
We described an in vitro 3-dimensional model to study the bactericidal activity of piperacillin (P), tazobactam (T) and amikacin (A) in combination against 5 strains of enterobacteria with different resistance patterns of beta-lactam antibiotics. A synergy was defined by calculation of sigma FBCP,T,A = BCp/MBCp + BCT/MBCT + BCA/MBCA and classic sigma FBCs for each double combination. The therapeutic value of each antibiotic was estimated by comparison of its bactericidal concentrations alone and in double or triple combination.
Assuntos
Quimioterapia Combinada/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Modelos Biológicos , Resistência beta-Lactâmica/genética , Amicacina/farmacologia , Antibacterianos/farmacologia , Enterobacteriaceae/genética , Inibidores Enzimáticos/farmacologia , Testes de Sensibilidade Microbiana , Ácido Penicilânico/análogos & derivados , Ácido Penicilânico/farmacologia , Penicilinas/farmacologia , Fenótipo , Piperacilina/farmacologia , Tazobactam , Inibidores de beta-LactamasesRESUMO
The activity of amoxycillin and ceftriaxone, alone and in combination, was tested against four strains of penicillin-resistant pneumococci in vitro and in an animal model. Three of the strains were also resistant to third-generation cephalosporins. Fractional inhibitory concentration indexes for combined amoxycillin and ceftriaxone were measured by the Etest method and were considered additive (1.2; 1.1; 1.3 and 1.3 for the four strains). Twenty-four hour time-kill curves for two strains showed that the combination was additive or synergic for concentrations up to the MIC of the single drugs. The efficacy of these antibiotics alone and in various combinations against strains 16089 and 11724 were investigated in vivo using prolonged (48 h) experimental fibrin clot infection in rabbits. The bacterial reductions (delta log10 cfu/g) obtained for all the antibiotic combinations tested were significantly higher than those of the single drug regimens. The in-vivo efficacy of amoxycillin was significantly correlated with the time for which its concentration was above the MIC and that of ceftriaxone was correlated with its maximal concentration. From these findings, we concluded that, at concentrations easily achievable in humans, the combination of amoxycillin and ceftriaxone was strongly synergic against infection due to penicillin- and cephalosporin-resistant pneumococci.
Assuntos
Amoxicilina/farmacologia , Ceftriaxona/farmacologia , Infecções Pneumocócicas/tratamento farmacológico , Streptococcus pneumoniae/efeitos dos fármacos , Amoxicilina/farmacocinética , Animais , Ceftriaxona/farmacocinética , Cefalosporinas/farmacocinética , Cefalosporinas/farmacologia , Relação Dose-Resposta a Droga , Resistência Microbiana a Medicamentos , Quimioterapia Combinada/farmacologia , Masculino , Testes de Sensibilidade Microbiana , Resistência às Penicilinas , Penicilinas/farmacocinética , Penicilinas/farmacologia , Coelhos , Fatores de TempoRESUMO
An in-vitro dialysis model was employed to assess the feasibility of once-daily dosing of cefodizime in the treatment of infections caused by various Enterobacteriaceae: Escherichia coli, Klebsiella pneumoniae, Morganella morganii, Serratia marcescens, Providencia stuartii and Enterobacter cloacae. This model simulated the concentrations of cefodizime detected in human blood after an intravenous (i.v.) bolus injection of 1 g or 2 g of the antibiotic. Validation of the model was undertaken to confirm its utility. Based on the data obtained with this model, once-daily dosing with 1 g cefodizime (i.v.) should be effective against infections due to the commonest Gram-negative bacteria (E. coli, K. pneumoniae, M. morganii). For infections caused by Enterobacteriaceae strains that produce large quantities of Class I beta-lactamases, twice-daily (P. stuartii or S. marcescens) or four times daily (E. cloacae) administration of 1 g cefodizime may be required.
Assuntos
Cefotaxima/análogos & derivados , Cefalosporinas/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Cefotaxima/farmacocinética , Cefotaxima/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Modelos BiológicosRESUMO
We studied the antipneumococcal efficacy of cefotaxime and vancomycin alone and a combination of cefotaxime with various dosages of vancomycin in the treatment of prolonged (48 h) experimental fibrin clot infections in rabbits. A clinical pneumococcal strain for which MICs were 2, 0.5 and 0.5 mg/L of penicillin, cefotaxime and vancomycin respectively, was used in this study. Cefotaxime was given iv at a fixed dose of 50 mg/kg and vancomycin iv at 1, 2.5, 5, 10 or 20 mg/kg. Maximal concentrations in clots were (mean +/- S.D.): 2.1 +/- 0.9, 1.1 +/- 0.4, 1.9 +/- 1, 2.3 +/- 1.5, 3.6 +/- 0.4 and 4 +/- 0.3 mg/g, respectively. The mean half-lives of elimination from clots were 2.2 h for cefotaxime and 7 h for vancomycin. We observed the highest bacterial reductions for the highest doses of vancomycin with or without cefotaxime. The combination of intermediate doses of vancomycin with cefotaxime led to higher antibacterial effects than either monotherapy. The low dose of vancomycin gave no significant additional effect compared with cefotaxime alone. The times of regrowth were similar for cefotaxime and cefotaxime-vancomycin 1, and also for vancomycin 10 and vancomycin 20 with or without cefotaxime but were significantly delayed for the combination cefotaxime-vancomycin 2.5 and cefotaxime-vancomycin 5 as compared with vancomycin 2.5 and vancomycin 5. By using a multivariate analysis, we demonstrated that the most important parameters were Cmax (r = 0.43) and AUC (r = 0.58) for cefotaxime alone and Cmax (r = 0.70) for vancomycin alone; none of the tested parameters was found to be significantly correlated with the efficacy of the combinations of cefotaxime and vancomycin. From these findings, and under the experimental conditions used (i.e., relatively low concentrations of cefotaxime), we demonstrated that the in-vivo antibacterial efficacy of the combination of cefotaxime and vancomycin was higher than each monotherapy when the local concentrations of vancomycin were at least 1.9 mg/L.
Assuntos
Cefotaxima/uso terapêutico , Quimioterapia Combinada/uso terapêutico , Resistência às Penicilinas/fisiologia , Infecções Pneumocócicas/tratamento farmacológico , Vancomicina/uso terapêutico , Análise de Variância , Animais , Cefotaxima/farmacocinética , Modelos Animais de Doenças , Quimioterapia Combinada/farmacocinética , Fibrina , Meia-Vida , Testes de Sensibilidade Microbiana , Infecções Pneumocócicas/metabolismo , Coelhos , Trombose/microbiologia , Resultado do Tratamento , Vancomicina/farmacocinéticaRESUMO
Using a clinical pneumococcal strain for which MICs were 4, 2, and 32 mg/liter for penicillin, amoxicillin, and fosfomycin, respectively, we studied the efficacies of these antibiotics alone and their combinations in the treatment of prolonged (48-h) experimental fibrin clot infection in rabbits. Treatments were as follows: amoxicillin IV at 20 mg/kg of body weight in one dose (Amo20), 50 mg/kg in one dose (Amo50), or two doses 6 h apart (Amo20 x 2 and Amo50 x 2); fosfomycin IV at a fixed dose of 50 mg/kg in one dose (Fos50) or two divided doses 6 h apart (Fos50 x 2); or the combinations of amoxicillin and fosfomycin with the same schedules. Maximum concentrations in clots were 2.03 +/- 1.02 and 2.13 +/- 0.33 mg/liter for Amo20 regimens, 3.7 +/- 1.9 and 4 +/- 1.3 mg/liter for Amo50 regimens, and 24 +/- 7 and 40 +/- 8 mg/liter for fosfomycin regimens, respectively. The mean half-lives of elimination from clots were between 2 and 3 h for amoxicillin regimens and between 5 and 7 h for fosfomycin. We observed the highest bacterial reductions (log10 CFU/gram) for Amo50 in two divided doses with or without fosfomycin. A significantly higher bacterial reduction than that with each monotherapy was observed when Amo20 was combined with fosfomycin in either one dose or two doses 6 h apart (0.16 +/- 0.8 and 1.64 +/- 1.6 log10 CFU/g for Amo20 in one and two doses, respectively, and 0.93 +/- 0.81 and 0.61 +/- 0.56 log10 CFU/g for fosfomycin in one and two doses, respectively, versus 3.46 +/- 1.26 and 3.16 +/- 1.31 log10 CFU/g for Amo20 plus fosfomycin in one and two doses, respectively [P < 0.001]). A time-dependent effect was observed with amoxicillin regimens. The time of regrowth was significantly delayed when amoxicillin was combined with fosfomycin. By using a multivariate analysis, we demonstrated that the most important parameter correlated to efficacy of the combination amoxicillin-fosfomycin was the length of the period during which the concentration of amoxicillin remained above the MIC. We demonstrated that the in vivo efficacy of the combination of amoxicillin and fosfomycin gave higher antibacterial effect than each monotherapy.
Assuntos
Quimioterapia Combinada/farmacologia , Fibrina/metabolismo , Infecções Pneumocócicas/tratamento farmacológico , Streptococcus pneumoniae/efeitos dos fármacos , Amoxicilina/farmacocinética , Amoxicilina/farmacologia , Amoxicilina/uso terapêutico , Animais , Antibacterianos/farmacocinética , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Contagem de Colônia Microbiana , Quimioterapia Combinada/farmacocinética , Quimioterapia Combinada/uso terapêutico , Fosfomicina/farmacocinética , Fosfomicina/farmacologia , Fosfomicina/uso terapêutico , Meia-Vida , Humanos , Resistência às Penicilinas , Penicilinas/farmacocinética , Penicilinas/farmacologia , Penicilinas/uso terapêutico , Infecções Pneumocócicas/microbiologia , CoelhosRESUMO
We report an outbreak of Enterobacter aerogenes in an intensive care unit (ICU) and two medicine departments that produced the extended-spectrum beta-lactamase TEM-24, which was difficult to detect by disk agar diffusion. The strains were compared by DNA restriction fragment length polymorphism after pulsed-field gel electrophoresis following cleavage with XbaI. This typing method indicated that a single strain, first isolated in the ICU, spread throughout the other medical departments as a result of patient transfer. We also observed the transfer in vivo of the plasmid encoding TEM-24 from the strain of Enterobacter aerogenes to different strains of Escherichia coli and Citrobacter freundii in the ICU. It therefore appears that the epidemic involved results from two events: dissemination of one strain of Enterobacter aerogenes and dissemination of the plasmid encoding TEM-24 among various members of the family Enterobacteriaceae.
Assuntos
Surtos de Doenças , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , beta-Lactamases/biossíntese , Antibacterianos/farmacologia , Sequência de Bases , Cromossomos Bacterianos/genética , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Primers do DNA/genética , DNA Bacteriano/genética , Resistência Microbiana a Medicamentos , Eletroforese em Gel de Campo Pulsado , Enterobacteriaceae/enzimologia , Enterobacteriaceae/genética , França/epidemiologia , Genótipo , Humanos , Unidades de Terapia Intensiva , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Dados de Sequência Molecular , Plasmídeos/genética , Reação em Cadeia da Polimerase , beta-Lactamases/genética , beta-LactamasRESUMO
An in vitro pharmacodynamic model was used to determine the killing kinetics of cefpirome against 20 Streptococcus pneumoniae strains (penicillin G MICs, > 0.125 to 2 micrograms/ml) isolated from patients with meningitis. The concentration of cefpirome was adjusted dynamically to simulate the median concentration profile obtained in the cerebrospinal fluid of adults after the infusion of a single dose of 2 g. The cefpirome MIC at which 90% of isolates are inhibited was 0.5 microgram/ml. Bactericidal activity was observed at 6 h, with mean killing of 3.51 +/- 0.34 log10 CFU/ml for all strains for which the cefpirome MIC was < 0.5 microgram/ml. In contrast, for strains for which the cefpirome MIC was > or = 0.5 microgram/ml, killing was significantly less (P < 0.05), with a mean reduction of only 2.86 +/- 0.57 log10 CFU/ml.
Assuntos
Cefalosporinas/farmacologia , Meningite Pneumocócica/microbiologia , Resistência às Penicilinas/fisiologia , Streptococcus pneumoniae/efeitos dos fármacos , Adulto , Ceftriaxona/farmacologia , Cefalosporinas/líquido cefalorraquidiano , Cefalosporinas/farmacocinética , Humanos , Meningite Pneumocócica/líquido cefalorraquidiano , Penicilinas/farmacologia , CefpiromaRESUMO
Using a clinical pneumococcal strain for which MICs were 2, 0.5, 0.5, and 16 mg/liter for penicillin, cefotaxime, ceftriaxone, and fosfomycin, respectively, we studied the efficacies of these antibiotics alone and in combination in one or two doses or in continuous infusion over 6 h in the treatment of the prolonged (48-h) experimental fibrin clot infections in rabbits. Doses were chosen to obtain low antibiotic concentrations. We observed the highest bacterial reductions (change in log10 CFU per gram) with the following five regimens: combination of cefotaxime plus fosfomycin given in two divided doses 6 h apart (each at 50 mg/kg of body weight given intravenously (4.2 +/- 0.7 CFU/g), ceftriaxone (8 mg/kg given once intravenously) along with one or two doses of fosfomycin (3.79 +/- 0.6 and 3.95 +/- 0.5 CFU/g), cefotaxime alone administered in two divided doses (3.6 +/- 0.4 CFU/g), and a 6-h continuous infusion of cefotaxime (100 mg/kg) with fosfomycin (100 mg/kg) (3.5 +/- 0.4 CFU/g). The bacterial reductions obtained with these five regimens were all higher than those obtained with the other regimens tested (P < 0.05). The time of bacterial regrowth was significantly delayed with the two doses of the cefotaxime-fosfomycin regimens (23.2 +/- 11 h) compared with those with the other combinations (P < 0.05). The rate of bacterial regrowth with this regimen was even lower than that observed with cefotaxime alone given in two doses (P < 0.05). By a multivariate analysis, the most important independent parameters for efficacy were the maximal concentrations of beta-lactam antibiotics and the residual concentration of fosfomycin and, for the combinations, the log of the area under the concentration-time curve/MIC ratio for beta-lactam antibiotics. From these findings, the combinations cefotaxime or ceftriaxone plus fosfomycin could be proposed for the treatment of infections caused by highly penicillin-resistant pneumococci.