RESUMEN
BACKGROUND: The glycopeptide teicoplanin is considered first-line treatment for severe infections caused by Gram-positive bacteria. Individualized treatment of teicoplanin is gaining interest. As only protein-unbound drug is pharmacologically active, a sensitive assay measuring unbound and total teicoplanin is indispensable for pharmacological research and dose optimization. OBJECTIVES: To develop and validate a UPLC-MS/MS method to quantify unbound and total teicoplanin in human serum. METHODS: The developed assay was validated according to the ICH guideline M10 on Bioanalytical Method Validation and study sample analysis. Unbound teicoplanin was obtained by ultrafiltration. The assay was cross-validated with a quantitative microsphere (QMS) immunoassay in a side-by-side comparison using 40 patient samples. RESULTS: With the developed and validated method, all main teicoplanin components (A2-1, A2-2/A2-3, A2-4/A2-5 and A3-1) can be quantified. Total run time was 5.5 min. Concentration range was 2.5-150 mg/L for total and 0.1-25 mg/L for unbound teicoplanin. Precision (coefficient of variation) and accuracy (bias) of total teicoplanin were 5.97% and 107%, respectively, and 7.17% and 108%, respectively, for unbound teicoplanin.Bland-Altman analysis showed total concentrations measured with the UPLC-MS/MS method were equivalent to the results of the QMS immunoassay. A total of 188 samples from 30 patients admitted to the ICU and haematology department were measured; total concentrations ranged between 2.92 and 98.5 mg/L, and unbound concentrations ranged between 0.37 and 30.7 mg/L. CONCLUSIONS: The developed method provided rapid, precise and accurate measurement of unbound and total teicoplanin. The developed method is now routinely applied in pharmacological research and clinical practice.
Asunto(s)
Espectrometría de Masas en Tándem , Teicoplanina , Humanos , Cromatografía Liquida , GlicopéptidosRESUMEN
BACKGROUND: To describe and evaluate a clinical decision support system (CDSS) for empirical antibiotic therapy using a systematic framework. METHODS: A reporting framework for behavior change intervention implementation was used, which includes several domains: development, evaluation and implementation. Within the development domain a description is given of the engagement of stakeholders, a rationale for how the CDSS may influence antibiotic prescribing and a detailed outline of how the system was developed. Within the evaluation domain a technical validation is performed and the interaction between potential users and the CDSS is analyzed. Within the domain of implementation a description is given on how the CDSS was tested in the real world and the strategies that were used for implementation and adoption of the CDSS. RESULTS: Development: a CDSS was developed, with the involvement of stakeholders, to assist empirical antibiotic prescribing by physicians. EVALUATION: Technical problems were determined during the validation process and corrected in a new CDSS version. A usability study was performed to assess problems in the system-user interaction. IMPLEMENTATION: In 114 patients the antibiotic advice that was generated by the CDSS was followed. For 54 patients the recommendations were not adhered to. CONCLUSIONS: This study describes the development and validation of a CDSS for empirical antibiotic therapy and shows the usefulness of the systematic framework for reporting CDSS interventions. In addition it shows that CDSS recommendations are not always adhered to which is associated with incorrect use of the system.
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Sistemas de Apoyo a Decisiones Clínicas , Médicos , Antibacterianos/uso terapéutico , HumanosRESUMEN
Murepavadin (POL7080) represents the first member of a novel class of outer membrane protein-targeting antibiotics. It specifically interacts with LptD and inhibits lipopolysaccharide (LPS) transport. Murepavadin is being developed for the treatment of serious infections by Pseudomonas aeruginosa We determined the plasma protein binding and the pharmacokinetics of murepavadin in plasma and epithelial lining fluid (ELF; pulmonary) in infected animals, and we determined the exposure-response relationship. Treatment of CD-1 neutropenic mice was started 2 h after infection using murepavadin at different dosing frequencies for 24 h, and the number of CFU per lung was determined. The sigmoid maximum-effect model was used to fit the dose-response, and the pharmacodynamic index (PDI) response was used to determine the PDI values, resulting in a static effect and 1-log kill reduction. Using R2 as an indicator of the best fit, the area under the concentration-time curve for the unbound fraction of the drug (fAUC)/MIC ratio correlated best with efficacy. The mean AUC required to provide a static effect was 36.83 mg h/liter (fAUC = 8.25 mg h/liter), and that to provide a 1-log reduction was 44.0 mg h/liter (fAUC = 9.86 mg h/liter). The mean static fAUC/MIC was determined to be 27.78, and that for a 1-log reduction was 39.85. These data may serve to determine doses in humans that are likely to be efficacious.
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Antibacterianos/farmacología , Antibacterianos/farmacocinética , Neutropenia/tratamiento farmacológico , Péptidos Cíclicos/farmacología , Péptidos Cíclicos/farmacocinética , Infecciones por Pseudomonas/tratamiento farmacológico , Animales , Área Bajo la Curva , Proteínas de la Membrana Bacteriana Externa/antagonistas & inhibidores , Infección Hospitalaria/tratamiento farmacológico , Infección Hospitalaria/prevención & control , Modelos Animales de Enfermedad , Ratones , Pruebas de Sensibilidad Microbiana , Neutropenia/microbiología , Pseudomonas aeruginosa/efectos de los fármacosRESUMEN
The in vitro susceptibilities of 1,099 molecularly identified clinical Candida isolates against 8 antifungal drugs were determined using the EUCAST microdilution method. A new simple, objective, and mathematically solid method for determining epidemiological cutoff values (ECOFFs) was developed by derivatizing the MIC distribution and determining the derivatized ECOFF (dECOFF) as the highest MIC with the maximum second derivative. The dECOFFs were similar (95% agreement within 1 dilution) to the EUCAST ECOFFs. Overall, low non-wild-type/resistance rates were found. The highest rates were found for azoles with C. parapsilosis (2.7 to 9.8%), C. albicans (7%), and C. glabrata (1.7 to 2.3%) and for echinocandins with C. krusei (3.3%), C. albicans (1%), and C. tropicalis (1.7%).
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Antifúngicos/farmacología , Candida/efectos de los fármacos , Candida/metabolismo , Pruebas de Sensibilidad Microbiana/métodos , Azoles/farmacología , Candida albicans/efectos de los fármacos , Candida albicans/metabolismo , Candida glabrata/efectos de los fármacos , Candida glabrata/metabolismo , Farmacorresistencia Fúngica , Modelos TeóricosRESUMEN
Although antibacterial therapy has an impact on human intestinal flora and the emergence of resistant bacteria, its role in the amplification of antimicrobial resistance and the quantitative exposure-effect relationship is not clear. An observational prospective study was conducted to determine whether and how ceftriaxone exposure is related to amplification of resistance in non-intensive care unit (non-ICU) patients. Serial stool samples from 122 extended-spectrum ß-lactamase-positive (ESBL+) hospitalized patients were analyzed by quantitative real-time PCR to quantify the resistant gene blaCTX-M Drug exposure was calculated for each patient by using a population pharmacokinetic model. Multi- and univariate regression and classification regression tree (CART) analyses were used to explore relationships between measures of exposure and amplification of blaCTX-M genes. Amplification of blaCTX-M was observed in 0% (0/11) of patients with no treatment and 33% (20/61) of patients treated with ceftriaxone. Stepwise regression analysis showed a significant association between amplification of blaCTX-M and the plasma area under the concentration-time curve from 0 to 24 h for the unbound fraction of the drug (fAUC0-24), the maximum concentration of drug in serum for the unbound fraction of the drug (fCmax), and the duration of ceftriaxone therapy. Using CART analysis, amplification of blaCTX-M was observed in 11/16 (69%) patients treated for >14 days and in 9/40 (23%) patients treated for ≤14 days (P = 0.0019). In the latter group, amplification was observed in 5/7 (71%) patients with an fAUC0-24 of ≥222 mg · h/liter and in 4/33 (12%) patients with lower drug exposures (P = 0.0033). A similar association was found for an fCmax of ≥30 mg/liter (63% versus 13%, P = 0.0079). A significant association was found between the amplification of blaCTX-M resistance genes and exposure to ceftriaxone. Both duration of treatment and degree of ceftriaxone exposure have a significant impact on the amplification of resistance genes. (The project described in this paper has been registered at ClinicalTrials.gov under identifier NCT01208519.).
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Antibacterianos/uso terapéutico , Ceftriaxona/uso terapéutico , Farmacorresistencia Bacteriana/genética , Proteínas de Escherichia coli/genética , Microbioma Gastrointestinal/efectos de los fármacos , Amplificación de Genes/genética , beta-Lactamasas/genética , Ceftriaxona/efectos adversos , Ceftriaxona/farmacocinética , Farmacorresistencia Bacteriana/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Hospitales , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Estudios ProspectivosRESUMEN
Ceftolozane is a new broad-spectrum cephalosporin and is combined with tazobactam to broaden the activity of ceftolozane against strains producing extended-spectrum beta-lactamases (ESBLs). We determined the pharmacodynamics (PD) of the combination in the neutropenic mouse thigh model to determine the optimal exposure of tazobactam. Treatment of CD-1 neutropenic mice was started 2 h after infection with ceftolozane every 2 h (q2h) alone or in combination with tazobactam at different dosing frequencies for 24 h, and the number of CFU in the thighs was determined before and after treatment. The maximum effect model was fit to the dose-response and the pharmacokinetic/PD index (PDI)-response to determine the PDI values for ceftolozane alone and ceftolozane in combination with tazobactam resulting in a static effect and a 1-log kill. The effect of tazobactam was dependent on the percentage of time that the free drug concentration remained above the concentration threshold (percent [Formula: see text]), whereby dosing q2h was more efficacious than dosing every 8 h (q8h), reducing the tazobactam daily dose by a factor 6.9 to 59.0 (n = 3 strains) to obtain a static effect. Using R2 as an indicator of the best fit of the percent [Formula: see text]-response relationships, the concentration threshold best correlating with the response varied from 0.5 to 2 mg/liter, depending on the strain. A similar result was obtained when the q2h and q8h regimens were analyzed. For all isolates tested, the mean [Formula: see text] for 0.5 mg/liter tazobactam was 28.2% (range, 17.5 to 45.8%) and 44.4% (range, 26.6 to 54.7%) for a static effect and a 1-log kill, respectively, at ceftolozane exposures that produced a ceftolozane concentration of 4 mg/liter (a concentration greater than the MIC) for 33.9 to 63.3% of a 24-h period under steady-state pharmacokinetic conditions. The main PDI that correlated with the effect of tazobactam was the [Formula: see text] achieved with a CT of 0.5 mg/liter tazobactam.
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Antibacterianos/farmacología , Cefalosporinas/farmacología , Cefalosporinas/farmacocinética , Escherichia coli/efectos de los fármacos , Klebsiella pneumoniae/efectos de los fármacos , Ácido Penicilánico/análogos & derivados , Animales , Quimioterapia Combinada , Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Proteínas de Escherichia coli/genética , Femenino , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/crecimiento & desarrollo , Ratones , Pruebas de Sensibilidad Microbiana , Ácido Penicilánico/farmacocinética , Ácido Penicilánico/farmacología , Tazobactam , beta-Lactamasas/genéticaRESUMEN
The emergence of resistant strains among common and rare Candida species necessitates continuous monitoring of the in vitro susceptibilities of those isolates. We therefore assessed the in vitro activities of micafungin against 1,099 molecularly identified isolates belonging to 5 common and 20 rare Candida species by the EUCAST, CLSI, and Etest methods, assessing both the intralaboratory agreement and the interlaboratory agreement for two centers. The median micafungin EUCAST MICs were as follows, from the lowest to the highest: for Candida albicans, 0.004 mg/liter; for C. glabrata, 0.016 mg/liter; for C. tropicalis, 0.031 mg/liter; for C. krusei, 0.125 mg/liter; for C. parapsilosis, 2 mg/liter. Among rare Candida species, high MICs were found for C. guilliermondii, C. lipolytica, C. orthopsilosis, C. metapsilosis, and C. fermentati. No resistant isolates were found by the CLSI method, whereas resistance rates of 1 to 2% were found by the EUCAST method. Overall, the EUCAST method resulted in MICs 1 to 2 dilutions higher than those found by the CLSI and Etest methods. The intra- and interlaboratory agreement between methods was >92%, except for the interlaboratory agreement between the EUCAST and CLSI methods (81%), where 17 to 31% of the differences were >2 2-fold dilutions for C. albicans, C. glabrata, C. tropicalis, and other rare Candida species and <6% for C. parapsilosis and C. krusei For the other interlaboratory comparisons, the EUCAST method resulted in higher MICs than the Etest method for all species, but <7% of these differences were >2 2-fold dilutions. Overall, the CLSI method resulted in lower MICs than the Etest method, with 11% of all isolates demonstrating >2 2-fold-dilution differences (6 to 20% for C. albicans, C. tropicalis, and rare Candida species; <5% for C. glabrata, C. krusei, and C. parapsilosis) and smaller differences found after 24 h. Despite these differences, categorical agreement was excellent (>97%), with only 1 to 2% very major errors between the EUCAST method and the other two methods.
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Antifúngicos/farmacología , Candida/efectos de los fármacos , Equinocandinas/farmacología , Lipopéptidos/farmacología , Pruebas de Sensibilidad Microbiana/métodos , Laboratorios/normas , Micafungina , Pruebas de Sensibilidad Microbiana/normasRESUMEN
Ceftolozane is a new cephalosporin with activity against Gram-negative and Gram-positive microorganisms. However, the compound is susceptible to degradation by extended-spectrum beta-lactamases (ESBLs). Tazobactam is an ESBL inhibitor and is combined with ceftolozane to broaden its activity. Surprisingly, although tazobactam has been available for over 20 years, few if any reliable data exist on the tazobactam pharmacokinetic (PK) properties in mice. To evaluate the PK and pharmacodynamic (PD) relationships in mice, the PK properties of tazobactam and ceftolozane were extensively investigated. Thigh-infected neutropenic CD-1 mice were injected intraperitoneally with a single 0.1-ml dose containing ceftolozane, tazobactam, or both compounds. Ceftolozane was applied in 2-fold-increasing doses of 4 mg/kg of body weight to 64 mg/kg alone or in combination. Tazobactam was combined in reverse doses (thus, 64/4 mg/kg, 32/8 mg/kg, etc.) (n = 2 per time point). In separate validation experiments, ceftolozane-tazobactam was given alone or in combination at 32/8 mg/kg and 8/32 mg/kg (n = 4 per time point). Plasma samples (one per mouse) and bronchoalveolar lavage samples were collected at up to 12 time points until 6 h after administration. There were no significant differences in the ceftolozane and tazobactam PK alone versus combined, indicating no PK interaction. The PKs were linear and dose proportional for both compounds and showed a good penetration in the epithelial lining fluid. The estimated mean (standard deviation) half-life of ceftolozane was 0.287 h (0.031 h), and that of tazobactam was 0.176 h (0.026), and the V was 0.43 liter/kg and 1.14 liter/kg, respectively. The estimates of tazobactam parameters can also be used to (re)interpret PD data.
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Antibacterianos/farmacocinética , Cefalosporinas/farmacocinética , Ácido Penicilánico/análogos & derivados , Animales , Antibacterianos/sangre , Antibacterianos/uso terapéutico , Cefalosporinas/sangre , Cefalosporinas/uso terapéutico , Escherichia coli/patogenicidad , Femenino , Klebsiella pneumoniae/patogenicidad , Ratones , Ácido Penicilánico/sangre , Ácido Penicilánico/farmacocinética , Ácido Penicilánico/uso terapéutico , Unión Proteica , Tazobactam , Muslo/microbiología , Muslo/patologíaRESUMEN
This study aimed to explore any mutation in the CYP51 gene conferring azole resistance in Aspergillus flavus. Two voriconazole-resistant and 45 voriconazole-susceptible isolates were included in the study. Sequence analysis demonstrated a T1025C nucleotide change in CYP51C, resulting in the Y319H amino acid substitution in one resistant isolate. However, the earlier described T788G mutation in CYP51C conferring voriconazole resistance in A. flavus isolates was present in all isolates, irrespective of their susceptibility status.
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Aspergillus flavus/efectos de los fármacos , Azoles/farmacología , Aspergillus flavus/genética , Farmacorresistencia Fúngica/genética , Proteínas Fúngicas/genética , Datos de Secuencia Molecular , Mutación , Voriconazol/farmacologíaRESUMEN
Major abscesses and diabetic foot infections (DFIs) are predominant subtypes of complicated skin and skin structure infections (cSSSIs), and are mainly caused by Staphylococcus aureus and ß-hemolytic streptococci. This study evaluates the potential benefit of direct pathogen-specific real-time polymerase chain reaction (PCR) assays in the identification of causative organisms of cSSSIs. One-hundred and fifty major abscess and 128 DFI biopsy samples were collected and microbial DNA was extracted by using the Universal Microbe Detection kit for tissue samples. Pathogen-specific PCRs were developed for S. aureus and its virulence factor Panton-Valentine leukocidin (PVL), Streptococcus pyogenes, S. agalactiae, S. dysgalactiae, and the S. anginosus group. Identification by pathogen-specific PCRs was compared to routine culture and both methods were considered as the gold standard for determination of the sensitivity and specificity of each assay. Direct real-time PCR assays of biopsy samples resulted in a 34 % higher detection of S. aureus, 37 % higher detection of S. pyogenes, 18 % higher detection of S. agalactiae, 4 % higher detection of S. dysgalactiae subspecies equisimilis, and 7 % higher detection of the S. anginosus group, compared to routine bacterial culture. The presence of PVL was mainly confined to S. aureus isolated from major abscess but not DFI biopsy samples. In conclusion, our pathogen-specific real-time PCR assays had a higher yield than culture methods and could be an additional method for the detection of relevant causative pathogens in biopsies.
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Absceso/diagnóstico , Pie Diabético/diagnóstico , Staphylococcus aureus/genética , Streptococcus/genética , Absceso/microbiología , Técnicas de Tipificación Bacteriana , Pie Diabético/microbiología , Humanos , Reacción en Cadena en Tiempo Real de la Polimerasa , Infecciones Estafilocócicas/diagnóstico , Infecciones Estafilocócicas/microbiología , Infecciones Estreptocócicas/diagnóstico , Infecciones Estreptocócicas/microbiología , Streptococcus/clasificaciónRESUMEN
BACKGROUND: Antimicrobial use in livestock is one of the factors contributing to selection and spread of resistant microorganisms in the environment. National veterinary antimicrobial consumption monitoring programs are therefore in place in a number of countries in the European Union. However, due to differences in methodology, results on veterinary antimicrobial consumption from these national monitoring programs cannot be compared internationally. International comparison is highly needed to establish regulations on veterinary antimicrobial use and reducing antimicrobial resistance. The aim of this study was to assess differences in the outcomes on veterinary antimicrobial consumption by applying three different sets of nationally established animal defined daily dosages to the same antimicrobial drug delivery dataset of Dutch pigs in 2012. METHODS: Delivery information for the complete Dutch pig sector for the year 2012 reported to the Netherlands Veterinary Medicines Authority (SDa) was analysed with three differently and nationally established animal defined daily dosages from the Netherlands and Denmark: the Defined Daily Dosage AnimalNL (DDDANL), the Animal Daily DosageDK (ADDDK) and Defined Animal Daily DosageDK (DADDDK). For each applied Dutch product equivalent, Danish products were identified based on authorization for pigs, active substance (including form), administration route, concentration and dosage regimen. RESULTS: Consumption in number of ADDDK/Y was lower than in number of DDDANL/Y for sows/piglets and finisher pigs, with proportions of 83.3 % and 98.3 %. Use in number of DADDDK/Y was even lower, 79.7 % for sows/piglets and 88.1 % for finisher pigs compared to number of DDDANL/Y. At therapeutic group level proportions of number of DADDDK/Y to number of DDDANL/Y were 63.6-150.4 % (sows/piglets) and 55.6-171.0 % (finisher pigs). Proportions were > 100 % for the polymyxines (sows/piglets 150.4 % and finisher pigs 149.9 %) and the macrolides/lincosamides (finisher pigs 171.0 %). CONCLUSIONS: Differences between nationally established animal defined daily dosages caused by different correction factors for long-acting products and national differences in authorized dosages, have a substantial influence on the results of antimicrobial consumption in pigs. To enable international comparison of veterinary antimicrobial consumption data, harmonized units of measurement, animal weights and animal (sub) categories are needed.
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Crianza de Animales Domésticos/métodos , Antiinfecciosos/análisis , Porcinos , Crianza de Animales Domésticos/normas , Animales , Antiinfecciosos/administración & dosificación , Antiinfecciosos/uso terapéutico , Países BajosRESUMEN
The percentage of the dosing interval that the non-protein-bound plasma concentration is above the MIC (%fT>MIC) for cephalosporins has been shown to correlate with microbiological outcomes in preclinical studies. However, clinical data are scarce. Using data from a randomized double-blind phase 3 clinical trial, we explored the relationship of ceftobiprole exposure with microbiological and clinical outcomes in patients with nosocomial pneumonia. The individual ceftobiprole exposure was determined for different pharmacokinetic (PK)/pharmacodynamic (PD) indices using individual pharmacokinetic data and a previously published population model. The MICs used in the analysis were the highest MICs for any bacterium cultured at baseline or the end of treatment (EOT). Outcomes were microbiological cure at EOT and clinical cure at test of cure (TOC). Multiple logistic regression (MLR) and classification and regression tree (CART) analyses were applied to determine the relationships among exposure, patient characteristics, and outcomes. MLR indicated that the %fT>MIC of ceftobiprole was the best predictor for both microbiological eradication and clinical cure. CART analysis showed a breakpoint value of 51.1% (n = 159; P = 0.0024) for clinical cure, whereas it was 62.2% (n = 251; P < 0.0001) for microbiological eradication. Other factors also contributed, particularly to clinical outcome. These included the difference between VAP and non-VAP patients, systemic inflammatory response syndrome (SIRS), creatinine clearance, the use of anti-Pseudomonas combination therapy, and Acute Physiology and Chronic Health Evaluation II (APACHE-II) score. There is a strong correlation between microbiological eradication and clinical cure with exposure to ceftobiprole. The %fT>MIC required to result in a favorable clinical outcome is >51% of the dosing interval, which is in line with the values found for microbiological eradication, the comparator ceftazidime, and preclinical models.
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Antibacterianos/uso terapéutico , Cefalosporinas/uso terapéutico , Neumonía/tratamiento farmacológico , Método Doble Ciego , Humanos , Modelos LogísticosRESUMEN
Although conventional amphotericin B was for many years the drug of choice and remains an important agent against invasive aspergillosis, reliable susceptibility breakpoints are lacking. Three clinical Aspergillus isolates (Aspergillus fumigatus, Aspergillus flavus, and Aspergillus terreus) were tested in an in vitro pharmacokinetic-pharmacodynamic model simulating the biphasic 24-h time-concentration profile of free amphotericin B concentrations in human serum with free peak concentrations (fCmax) of 0.1, 0.3, 0.6, 1.2, and 2.4 mg/liter administered once daily. Drug concentrations were measured with a bioassay, and fungal growth was monitored for 72 h with galactomannan production. The fCmax/MIC corresponding to half-maximal activity (P50) was determined for each species, and the percentage of target attainment was calculated for different MICs for the standard (1 mg/kg of body weight) and a lower (0.6-mg/kg) dose of amphotericin B with Monte Carlo simulation analysis. The fCmax/MICs (95% confidence intervals) corresponding to P50 were 0.145 (0.133 to 0.158), 0.371 (0.283 to 0.486), and 0.41 (0.292 to 0.522) for A. fumigatus, A. flavus, and A. terreus, respectively. The median percentages of P50 attainment were ≥88%, 47%, and 0% for A. fumigatus isolates with MICs of ≤0.5, 1, and ≥2 mg/liter, respectively, and ≥81%, 24%, and 0% and ≥75%, 15%, and 0% for A. flavus and A. terreus isolates with MICs of ≤0.25, 0.5, and ≥1 mg/liter, respectively. The lower dose of 0.6 mg/kg would retain efficacy for A. fumigatus, A. flavus, and A. terreus isolates with MICs of ≤0.25, ≤0.125, and ≤0.125 mg/liter, respectively. The susceptibility, intermediate susceptibility, and resistance breakpoints of ≤0.5, 1, and ≥2 mg/liter for A. fumigatus and ≤0.25, 0.5, and ≥1 mg/liter for A. flavus and A. terreus were determined for conventional amphotericin B with a pharmacokinetic-pharmacodynamic model simulating free-drug serum concentrations.
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Anfotericina B/farmacología , Antifúngicos/farmacología , Aspergillus/efectos de los fármacos , Humanos , Pruebas de Sensibilidad Microbiana , Método de MontecarloRESUMEN
Species of Verruconis and species of Ochroconis are dematiaceous fungi generally found in the environment but having the ability to infect humans, dogs, cats, poultry, and fish. This study presents the antifungal susceptibility patterns of these fungi at the species level. Forty strains originating from clinical and environmental sources were phylogenetically identified at the species level by using sequences of the ribosomal DNA internal transcribed spacer (rDNA ITS). In vitro antifungal susceptibility testing was performed against eight antifungals, using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. The geometric mean MICs for amphotericin B (AMB), flucytosine (5FC), fluconazole (FLC), itraconazole (ITC), voriconazole (VRC), and posaconazole (POS) and minimum effective concentrations (MECs) for caspofungin (CAS) and anidulafungin (AFG) across the Ochroconis and Verruconis species were as follows, in increasing order. For Verruconis species, the values (µg/ml) were as follows: AFG, 0.04; POS, 0.25; ITC, 0.37; AMB, 0.50; CAS, 0.65; VRC, 0.96; 5FC, 10.45; and FLC, 47.25. For Ochroconis species, the values (µg/ml) were as follows: AFG, 0.06; POS, 0.11; CAS, 0.67; VRC, 2.76; ITC, 3.94; AMB, 5.68; 5FC, 34.48; and FLC, 61.33. Antifungal susceptibility of Ochroconis and Verruconis was linked with phylogenetic distance and thermotolerance. Echinocandins and POS showed the greatest in vitro activity, providing possible treatment options for Ochroconis and Verruconis infections.
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Antifúngicos/farmacología , Ascomicetos/efectos de los fármacos , Hongos Mitospóricos/efectos de los fármacos , Micosis/microbiología , Ascomicetos/genética , ADN de Hongos/genética , ADN Ribosómico/genética , ADN Espaciador Ribosómico/genética , Pruebas de Sensibilidad Microbiana , Hongos Mitospóricos/genéticaRESUMEN
Complicated skin and skin structure infections (cSSSIs) are caused by Gram-positive and Gram-negative, aerobic and anaerobic pathogens, with a polymicrobial aetiology being frequent. Recognition of invading pathogens by the immune system results in the production of pro- and anti-inflammatory cytokines, which are extremely important for intercellular communication and control of infection. This study assessed whether genetic variation in genes encoding cytokines influences the susceptibility to cSSSIs. For the association study, 318 patients with cSSSI and 328 healthy controls were genotyped for single nucleotide polymorphisms (SNPs) in cytokine genes IL1A, IL1B, IL1RN, TNF, IL10, IL17A, IL17F and IFNG. For immunological validation, peripheral blood mononuclear cells (PBMCs) from 74 healthy individuals, genotyped for SNPs of interest, were stimulated with Staphylococcus aureus or Escherichia coli and corresponding cytokine levels were determined by enzyme-linked immunosorbent assay (ELISA). Polymorphisms IL6 rs1800797, TNF rs1800629, IL10 rs1800871, IL17A rs8193036 and IFNG rs2069705 influenced susceptibility to cSSSIs. No differences in cytokine responses, stratified for genotype, were detected after PBMC stimulation. No association with cSSSIs was observed for polymorphisms IL1A rs17561 and rs1800587, IL1B rs16944 and rs1143627, IL1RN rs4251961, TNF rs361525, IL10 rs1800896, IL17A rs2275913 and IL17F rs763780. In conclusion, polymorphisms in IL6, TNF, IL10, IL17A and IFNG are associated with susceptibility to cSSSIs.
Asunto(s)
Citocinas/genética , Enfermedades Cutáneas Bacterianas/genética , Análisis de Varianza , Estudios de Casos y Controles , Predisposición Genética a la Enfermedad , Humanos , Modelos Logísticos , Polimorfismo de Nucleótido Simple , Reproducibilidad de los Resultados , Enfermedades Cutáneas Bacterianas/inmunologíaRESUMEN
The emergence of decreased ciprofloxacin susceptibility (DCS) in Salmonella enterica serovar Typhi and serovar Paratyphi A, B or C limits treatment options. We studied the impact of DCS isolates on the fate of travellers returning with enteric fever and possible alternative treatment options. We evaluated the clinical features, susceptibility data and efficacy of empirical treatment in patients with positive blood cultures of a DCS isolate compared to patients infected with a ciprofloxacin-susceptible (CS) isolate in the period from January 2002 to August 2008. In addition, the pharmacokinetic and pharmacodynamic parameters of ciprofloxacin, levofloxacin and gatifloxacin were determined to assess if increasing the dose would result in adequate unbound fraction of the drug 24-h area under the concentration-time curve/minimum inhibitory concentration (ƒAUC(0-24)/MIC) ratio. Patients with DCS more often returned from the Indian subcontinent and had a longer fever clearance time and length of hospital stay compared to patients in whom the initial empirical therapy was adequate. The mean ƒAUC(0-24)/MIC was 41.3 ± 18.8 in the patients with DCS and 585.4 ± 219 in patients with a CS isolate. For DCS isolates, the mean ƒAUC0-24/MIC for levofloxacin was 60.5 ± 28.7 and for gatifloxacin, it was 97.9 ± 28.0. Increasing the dose to an adequate ƒAUC(0-24)/MIC ratio will lead to conceivably toxic drug levels in 50% of the patients treated with ciprofloxacin. Emerging DCS isolates has led to the failure of empirical treatment in ill-returned travellers. We demonstrated that, in some cases, an adequate ƒAUC(0-24)/MIC ratio could be achieved by increasing the dose of ciprofloxacin or by the use of alternative fluoroquinolones.
Asunto(s)
Antibacterianos/farmacología , Ciprofloxacina/farmacología , Farmacorresistencia Bacteriana , Salmonella paratyphi A/efectos de los fármacos , Salmonella typhi/efectos de los fármacos , Viaje , Adolescente , Adulto , Anciano , Antibacterianos/administración & dosificación , Antibacterianos/farmacocinética , Sangre/microbiología , Niño , Ciprofloxacina/administración & dosificación , Ciprofloxacina/farmacocinética , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Fiebre Paratifoidea/microbiología , Estudios Retrospectivos , Salmonella paratyphi A/aislamiento & purificación , Salmonella typhi/aislamiento & purificación , Resultado del Tratamiento , Fiebre Tifoidea/microbiología , Adulto JovenRESUMEN
Epidemiological cutoff values (ECV) are commonly used to separate wild-type isolates from isolates with reduced susceptibility to antifungal drugs, thus setting the foundation for establishing clinical breakpoints for Aspergillus fumigatus. However, ECVs are usually determined by eye, a method which lacks objectivity, sensitivity, and statistical robustness and may be difficult, in particular, for extended and complex MIC distributions. We therefore describe and evaluate a statistical method of MIC distribution analysis for posaconazole, itraconazole, and voriconazole for 296 A. fumigatus isolates utilizing nonlinear regression analysis, the normal plot technique, and recursive partitioning analysis incorporating cyp51A sequence data. MICs were determined by using the CLSI M38-A2 protocol (CLSI, CLSI document M38-A2, 2008) after incubation of the isolates for 48 h and were transformed into log(2) MICs. We found a wide distribution of MICs of all azoles, some ranging from 0.02 to 128 mg/liter, with median MICs of 32 mg/liter for itraconazole, 4 mg/liter for voriconazole, and 0.5 mg/liter for posaconazole. Of the isolates, 65% (192 of 296) had mutations in the cyp51A gene, and the majority of the mutants (90%) harbored tandem repeats in the promoter region combined with mutations in the cyp51A coding region. MIC distributions deviated significantly from normal distribution (D'Agostino-Pearson omnibus normality test P value, <0.001), and they were better described with a model of the sum of two Gaussian distributions (R(2), 0.91 to 0.96). The normal plot technique revealed a mixture of two populations of MICs separated by MICs of 1 mg/liter for itraconazole, 1 mg/liter for voriconazole, and 0.125 mg/liter for posaconazole. Recursive partitioning analysis confirmed these ECVs, since the proportions of isolates harboring cyp51A mutations associated with azole resistance were less than 20%, 20 to 30%, and >70% when the MICs were lower than, equal to, and higher than the above-mentioned ECVs, respectively.
Asunto(s)
Antifúngicos/administración & dosificación , Aspergilosis/tratamiento farmacológico , Aspergillus fumigatus/genética , Sistema Enzimático del Citocromo P-450/genética , Farmacorresistencia Fúngica/genética , Proteínas Fúngicas/genética , Modelos Estadísticos , Antifúngicos/uso terapéutico , Aspergilosis/epidemiología , Aspergilosis/microbiología , Aspergillus fumigatus/efectos de los fármacos , Aspergillus fumigatus/aislamiento & purificación , Farmacorresistencia Fúngica/efectos de los fármacos , Humanos , Itraconazol/administración & dosificación , Itraconazol/uso terapéutico , Estudios Longitudinales , Cómputos Matemáticos , Pruebas de Sensibilidad Microbiana , Mutación , Países Bajos/epidemiología , Regiones Promotoras Genéticas , Pirimidinas/administración & dosificación , Pirimidinas/uso terapéutico , Análisis de Secuencia de ADN , Secuencias Repetidas en Tándem , Triazoles/administración & dosificación , Triazoles/uso terapéutico , VoriconazolRESUMEN
We assessed the effect of increasing manganese concentrations in test media (0.001 to 1,024 mg/liter) on MICs of tigecycline. For both broth microdilution (BMD) and Etests, this effect was negligible for physiological concentrations, but MICs increased when concentrations exceeded 8 mg/liter. Susceptibility testing should be performed on media with standardized low manganese content.
Asunto(s)
Acinetobacter baumannii/efectos de los fármacos , Medios de Cultivo/química , Enterobacteriaceae/efectos de los fármacos , Manganeso/metabolismo , Minociclina/análogos & derivados , Estudios de Cohortes , Farmacorresistencia Bacteriana , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Pruebas de Sensibilidad Microbiana/normas , Minociclina/farmacología , Estudios Prospectivos , TigeciclinaRESUMEN
Mortality in patients admitted with sepsis is high and the increasing incidence of infections with multiresistant bacteria is a worldwide problem. Many hospitals have local antimicrobial guidelines to assure effective treatment and limit the use of broad-spectrum antibiotics, thereby reducing the selection of resistant bacteria. We evaluated adherence to the antimicrobial treatment guidelines of our hospital in patients presenting to the emergency department (ED) with sepsis and assessed the in vitro susceptibility of isolated pathogens to the guideline-recommended treatment and the prescribed treatment. We included all adult patients with a known or suspected infection and two or more extended systemic inflammatory response syndrome (SIRS) criteria. Patients who did not receive antimicrobial treatment, presented with infections not included in the guidelines, or had more than one possible focus of infection were excluded. A total of 276 ED visits (262 patients) were included. Guideline-concordant treatment was prescribed in 168 visits (61%). In the case of guideline-disconcordant treatment, 87% was more broad-spectrum than guideline-recommended treatment. A microbiological diagnosis was established in 96 visits (35%). The susceptibility of the pathogens isolated from patients treated with guideline-concordant treatment (n=68) and guideline-disconcordant treatment (n=28) to guideline-recommended treatment (91% versus 89%) and to prescribed treatment (91% versus 93%) was similar (p=0.77 and p=0.79, respectively). In conclusion, non-adherence to the guidelines occurred frequently and resulted in more broad-spectrum empirical therapy. This did not result in a higher rate of susceptibility of the isolated pathogens to the prescribed empirical therapy.