RESUMEN
In order to detect the in vitro activity of tigecycline against multiple resistant gram-negative bacilli isolated in our hospital, tigecycline susceptibilities of clinical isolates of multiple and/or panresistant 100 Acinetobacter baumannii isolates, and 38 carbapenem resistant Klebsiella pneumoniae (17 of which were panresistant), obtained between January 2005 and August 2007, were evaluated by using E-test (AB Biodisc, Sweden). Carbapenem resistance rate was found to be 59% for A.baumannii, using Vitek2 Compact System (Bio-Merieux, France) which is present in our laboratory for routine use. Minimal inhibitory concentration (MIC) levels for tigecycline were < or =2 mcg/ml in 93% of the isolates while the MIC level was 3 mcg/ml for 7% of the isolates. Tigecycline MIC50 and MIC 90 values were 1.5 and 2 mcg/ml, respectively. Among K. pneumoniae the least resistance was detected against amikacin (52.6% resistant) while tigecycline MIC levels were between 0.13 mcg/ml and 2 mcg/ml. All of the K.pneumoniae strains were susceptible to tigecycline, and the MIC50 ve MIC90 values of these isolates were 1 mcg/ml and 1.5 mcg/ml, respectively. The in vitro susceptibility rates of tigecycline against multiple and/or panresistant A. baumannii and K. pneumoniae isolates are found to be promising for use in therapy.
Asunto(s)
Acinetobacter baumannii/efectos de los fármacos , Antibacterianos/farmacología , Klebsiella pneumoniae/efectos de los fármacos , Minociclina/análogos & derivados , Carbapenémicos/farmacología , Farmacorresistencia Bacteriana Múltiple , Humanos , Pruebas de Sensibilidad Microbiana , Minociclina/farmacología , Tigeciclina , Resistencia betalactámicaRESUMEN
Increasing resistance due to extended-spectrum beta-lactamases (ESBLs) and multiple resistance mechanisms in gram-negative hospital isolates restrict the role of beta-lactam antibiotics in empirical treatment of serious infections. As the prevalence of ESBL producing strains and resistance rates to antimicrobial agents can vary in each center, local surveillance studies are required to guide therapy. In this study, in vitro rates of resistance to ceftriaxone, ceftazidime, cefepime, imipenem, cefoperazone/sulbactam and piperacillin/tazobactam were evaluated in 1196 gram-negative hospital isolates in a multicenter in vitro study with the participation of six different centers in Turkey between the period of June 2004-January 2005. The isolates included Escherichia coli (n= 457), Klebsiella pneumoniae (n= 390), Pseudomonas aeruginosa (n= 194) and Acinetobacter boumannii (n= 155). In addition, frequency of ESBL production and types of enzymes were determined in blood isolates of E. coli and K. pneumoniae. MICs and ESBL production were investigated by E-test (AB Biodisk, Solna) and the results were evaluated by using CLSI breakpoints. PCR analysis was used for typing of the ESBLs. In E. coli, 26% and in K. pneumoniae 32% of the isolates were ESBL producers. Among the blood isolates of E. coli and K. pneumoniae, 31.7% and 33.3% produced ESBLs, respectively. CTX-M (71.4%) was the most prevalent enzyme, followed by TEM (49.4%) and SHV (46.7%) derived enzymes. CTX-M-15 (69.4%) was the most frequent CTX-M type in blood isolates followed by CTX-M-3 (28.6%) and CTX-M-1 (2%). Resistance to imipenem was not observed in E. coli isolates, however it was 1.3% in K. pneumoniae, 28.9% in P. aeruginosa and 52.2% in A. baumannii strains. Resistance to cefoperazone/sulbactam was found as 6%, 17.7%, 27.9% and 41.3% in E. coli, K. pneumoniae, P. aeruginosa and A. baumannii isolates, respectively, whereas resistance rates to piperacillin/tazobactam were 10.2%, 22.3%, 22.7% and 78.7%, respectively. These results indicate that ESBL production and rates of resistance to beta-lactam antibiotics are high in hospital isolates of gram-negative bacteria in Turkey, however, they show variations in different hospitals and CTX-M enzymes are prevalent in these isolates.
Asunto(s)
Antibacterianos/farmacología , Infección Hospitalaria/microbiología , Bacterias Gramnegativas/efectos de los fármacos , Infecciones por Bacterias Gramnegativas/microbiología , beta-Lactamasas/metabolismo , Acinetobacter baumannii/efectos de los fármacos , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Infección Hospitalaria/tratamiento farmacológico , Farmacorresistencia Bacteriana Múltiple , Escherichia coli/efectos de los fármacos , Bacterias Gramnegativas/enzimología , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Pseudomonas aeruginosa/efectos de los fármacos , TurquíaRESUMEN
Candida dubliniensis which was first recognized in 1995 can be easily misidentified because of its phenotypic similarities with Candida albicans. In this study blood samples of patients from various departments of Ankara University Medical Faculty between January 2001-June 2004 were investigated for the distribution of Candida spp. and the presence of C. dubliniensis. Culture positive 67 fungi were included to the study. Phenotypic tests such as chlamydospore formation, colony morphology on Staib agar, growth at 45 degrees C, carbohydrate assimilation profiles were investigated for identification and differentiation of C. dubliniensis from C. albicans. To confirm the results polymerase chain reaction were used for suspected C. albicans and C. dubliniensis isolates. Among 38 germ tube and chlamydospore forming isolates, 37 of them were found as C. albicans and one as C. dubliniensis. The incidence of C. dubliniensis in our hospital is still low, this is the first C. dubliniensis isolate as an agent of candidaemia reported from Turkey.
Asunto(s)
Candida/clasificación , Candidiasis/microbiología , Fungemia/microbiología , Candida/aislamiento & purificación , Candida/fisiología , ADN de Hongos/genética , Hospitales de Enseñanza , Humanos , Reacción en Cadena de la Polimerasa , TurquíaRESUMEN
This study was conducted upon the detection of discordant results obtained for Acinetobacter species against meropenem by disk diffusion susceptibility and E-test method. The aim of this study was to investigate the reliability of disk diffusion method for the determination of carbapenem susceptibility in non-fermentative bacilli. Carbapenem (imipenem and meropenem) sensitivites of 157 Acinetobacter baumanii and 157 Pseudomonas aeruginosa strains were performed by disk diffusion test and E-test in our laboratory where quality control of antibiotic susceptibility tests are performed weekly. For meropenem, discordance of the two tests were 10.8% and 4.5% for A. baumannii and P. aeruginosa, respectively. MIC values and disk diffusion zone diameters were significantly different from each other. There was no difference in terms of imipenem in A. baumannii strains but 5.1% of P. aeruginosa isolates showed discordance. Since, for the P. aeruginosa isolates with discordant imipenem susceptibility results, the imipenem disk diffusion zones were close to the lower level and their MIC values were within the intermediate resistance range, it was assumed that this technical discordance had low risk of reproducibility. In routine laboratories, meropenem resistance detected by disk diffusion method, should be verified by another technique. This is not only important for patient results but for epidemiological data as well. Routine quality control studies for antibiotic susceptibility tests and close observation of suspicious results, is mandatory for each laboratory, in order to achieve good quality performance.