RESUMEN
Since epidemiological cutoff values (ECVs) using CLSI MICs from multiple laboratories are not available for Candida spp. and the echinocandins, we established ECVs for anidulafungin and micafungin on the basis of wild-type (WT) MIC distributions (for organisms in a species-drug combination with no detectable acquired resistance mechanisms) for 8,210 Candida albicans, 3,102 C. glabrata, 3,976 C. parapsilosis, 2,042 C. tropicalis, 617 C. krusei, 258 C. lusitaniae, 234 C. guilliermondii, and 131 C. dubliniensis isolates. CLSI broth microdilution MIC data gathered from 15 different laboratories in Canada, Europe, Mexico, Peru, and the United States were aggregated to statistically define ECVs. ECVs encompassing 97.5% of the statistically modeled population for anidulafungin and micafungin were, respectively, 0.12 and 0.03 µg/ml for C. albicans, 0.12 and 0.03 µg/ml for C. glabrata, 8 and 4 µg/ml for C. parapsilosis, 0.12 and 0.06 µg/ml for C. tropicalis, 0.25 and 0.25 µg/ml for C. krusei, 1 and 0.5 µg/ml for C. lusitaniae, 8 and 2 µg/ml for C. guilliermondii, and 0.12 and 0.12 µg/ml for C. dubliniensis. Previously reported single and multicenter ECVs defined in the present study were quite similar or within 1 2-fold dilution of each other. For a collection of 230 WT isolates (no fks mutations) and 51 isolates with fks mutations, the species-specific ECVs for anidulafungin and micafungin correctly classified 47 (92.2%) and 51 (100%) of the fks mutants, respectively, as non-WT strains. These ECVs may aid in detecting non-WT isolates with reduced susceptibility to anidulafungin and micafungin due to fks mutations.
Asunto(s)
Antifúngicos/farmacología , Candida/efectos de los fármacos , Equinocandinas/farmacología , Proteínas Fúngicas/genética , Lipopéptidos/farmacología , Anidulafungina , Candida/clasificación , Candida/genética , Candida/aislamiento & purificación , Candidiasis/epidemiología , Candidiasis/microbiología , Europa (Continente)/epidemiología , Expresión Génica , Humanos , Micafungina , Pruebas de Sensibilidad Microbiana , Mutación , América del Norte/epidemiología , América del Sur/epidemiologíaRESUMEN
Although Clinical and Laboratory Standards Institute (CLSI) clinical breakpoints (CBPs) are available for interpreting echinocandin MICs for Candida spp., epidemiologic cutoff values (ECVs) based on collective MIC data from multiple laboratories have not been defined. While collating CLSI caspofungin MICs for 145 to 11,550 Candida isolates from 17 laboratories (Brazil, Canada, Europe, Mexico, Peru, and the United States), we observed an extraordinary amount of modal variability (wide ranges) among laboratories as well as truncated and bimodal MIC distributions. The species-specific modes across different laboratories ranged from 0.016 to 0.5 µg/ml for C. albicans and C. tropicalis, 0.031 to 0.5 µg/ml for C. glabrata, and 0.063 to 1 µg/ml for C. krusei. Variability was also similar among MIC distributions for C. dubliniensis and C. lusitaniae. The exceptions were C. parapsilosis and C. guilliermondii MIC distributions, where most modes were within one 2-fold dilution of each other. These findings were consistent with available data from the European Committee on Antimicrobial Susceptibility Testing (EUCAST) (403 to 2,556 MICs) for C. albicans, C. glabrata, C. krusei, and C. tropicalis. Although many factors (caspofungin powder source, stock solution solvent, powder storage time length and temperature, and MIC determination testing parameters) were examined as a potential cause of such unprecedented variability, a single specific cause was not identified. Therefore, it seems highly likely that the use of the CLSI species-specific caspofungin CBPs could lead to reporting an excessive number of wild-type (WT) isolates (e.g., C. glabrata and C. krusei) as either non-WT or resistant isolates. Until this problem is resolved, routine testing or reporting of CLSI caspofungin MICs for Candida is not recommended; micafungin or anidulafungin data could be used instead.
Asunto(s)
Antifúngicos/uso terapéutico , Candida/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Equinocandinas/uso terapéutico , Anidulafungina , Candida/crecimiento & desarrollo , Candida/aislamiento & purificación , Candidiasis/microbiología , Caspofungina , Farmacorresistencia Fúngica , Europa (Continente) , Humanos , Lipopéptidos/uso terapéutico , Micafungina , Pruebas de Sensibilidad Microbiana/normas , Pruebas de Sensibilidad Microbiana/estadística & datos numéricos , América del Norte , Variaciones Dependientes del Observador , América del Sur , Especificidad de la EspecieRESUMEN
Epidemiological cutoff values (ECVs) for the Cryptococcus neoformans-Cryptococcus gattii species complex versus fluconazole, itraconazole, posaconazole, and voriconazole are not available. We established ECVs for these species and agents based on wild-type (WT) MIC distributions. A total of 2,985 to 5,733 CLSI MICs for C. neoformans (including isolates of molecular type VNI [MICs for 759 to 1,137 isolates] and VNII, VNIII, and VNIV [MICs for 24 to 57 isolates]) and 705 to 975 MICs for C. gattii (including 42 to 260 for VGI, VGII, VGIII, and VGIV isolates) were gathered in 15 to 24 laboratories (Europe, United States, Argentina, Australia, Brazil, Canada, Cuba, India, Mexico, and South Africa) and were aggregated for analysis. Additionally, 220 to 359 MICs measured using CLSI yeast nitrogen base (YNB) medium instead of CLSI RPMI medium for C. neoformans were evaluated. CLSI RPMI medium ECVs for distributions originating from at least three laboratories, which included ≥95% of the modeled WT population, were as follows: fluconazole, 8 µg/ml (VNI, C. gattii nontyped, VGI, VGIIa, and VGIII), 16 µg/ml (C. neoformans nontyped, VNIII, and VGIV), and 32 µg/ml (VGII); itraconazole, 0.25 µg/ml (VNI), 0.5 µg/ml (C. neoformans and C. gattii nontyped and VGI to VGIII), and 1 µg/ml (VGIV); posaconazole, 0.25 µg/ml (C. neoformans nontyped and VNI) and 0.5 µg/ml (C. gattii nontyped and VGI); and voriconazole, 0.12 µg/ml (VNIV), 0.25 µg/ml (C. neoformans and C. gattii nontyped, VNI, VNIII, VGII, and VGIIa,), and 0.5 µg/ml (VGI). The number of laboratories contributing data for other molecular types was too low to ascertain that the differences were due to factors other than assay variation. In the absence of clinical breakpoints, our ECVs may aid in the detection of isolates with acquired resistance mechanisms and should be listed in the revised CLSI M27-A3 and CLSI M27-S3 documents.
Asunto(s)
Antifúngicos/uso terapéutico , Criptococosis/tratamiento farmacológico , Criptococosis/epidemiología , Cryptococcus gattii/efectos de los fármacos , Fluconazol/uso terapéutico , Itraconazol/uso terapéutico , Pirimidinas/uso terapéutico , Triazoles/uso terapéutico , Antifúngicos/farmacología , Australia/epidemiología , Criptococosis/microbiología , Cryptococcus gattii/crecimiento & desarrollo , Cryptococcus gattii/aislamiento & purificación , Farmacorresistencia Fúngica/efectos de los fármacos , Europa (Continente)/epidemiología , Fluconazol/farmacología , Humanos , India/epidemiología , Itraconazol/farmacología , Pruebas de Sensibilidad Microbiana , América del Norte/epidemiología , Pirimidinas/farmacología , Sudáfrica/epidemiología , América del Sur/epidemiología , Triazoles/farmacología , VoriconazolRESUMEN
Clinical breakpoints (CBPs) and epidemiological cutoff values (ECVs) have been established for several Candida spp. and the newer triazoles and echinocandins but are not yet available for older antifungal agents, such as amphotericin B, flucytosine, or itraconazole. We determined species-specific ECVs for amphotericin B (AMB), flucytosine (FC) and itraconazole (ITR) for eight Candida spp. (30,221 strains) using isolates from 16 different laboratories in Brazil, Canada, Europe, and the United States, all tested by the CLSI reference microdilution method. The calculated 24- and 48-h ECVs expressed in µg/ml (and the percentages of isolates that had MICs less than or equal to the ECV) for AMB, FC, and ITR, respectively, were 2 (99.8)/2 (99.2), 0.5 (94.2)/1 (91.4), and 0.12 (95.0)/0.12 (92.9) for C. albicans; 2 (99.6)/2 (98.7), 0.5 (98.0)/0.5 (97.5), and 2 (95.2)/4 (93.5) for C. glabrata; 2 (99.7)/2 (97.3), 0.5 (98.7)/0.5 (97.8), and 05. (99.7)/0.5 (98.5) for C. parapsilosis; 2 (99.8)/2 (99.2), 0.5 (93.0)/1 (90.5), and 0.5 (97.8)/0.5 (93.9) for C. tropicalis; 2 (99.3)/4 (100.0), 32 (99.4)/32 (99.3), and 1 (99.0)/2 (100.0) for C. krusei; 2 (100.0)/4 (100.0), 0.5 (95.3)/1 (92.9), and 0.5 (95.8)/0.5 (98.1) for C. lusitaniae; -/2 (100.0), 0.5 (98.8)/0.5 (97.7), and 0.25 (97.6)/0.25 (96.9) for C. dubliniensis; and 2 (100.0)/2 (100.0), 1 (92.7)/-, and 1 (100.0)/2 (100.0) for C. guilliermondii. In the absence of species-specific CBP values, these wild-type (WT) MIC distributions and ECVs will be useful for monitoring the emergence of reduced susceptibility to these well-established antifungal agents.
Asunto(s)
Anfotericina B/farmacología , Antifúngicos/farmacología , Candida/efectos de los fármacos , Candidiasis/microbiología , Flucitosina/farmacología , Itraconazol/farmacología , Brasil , Canadá , Candida/aislamiento & purificación , Europa (Continente) , Humanos , Pruebas de Sensibilidad Microbiana/normas , Estados UnidosRESUMEN
BACKGROUND: Pathogen frequency and resistance patterns may vary significantly from country to country and also in different hospitals within a country. Thus, regional surveillance programs are essential to guide empirical therapy and infection control measures. METHODS: Rank order of occurrence and antimicrobial susceptibility of pathogenic species causing bloodstream infections (BSI), lower respiratory tract infections (LRTI), wound or skin and soft tissue infections (WSSTI), and urinary tract infections (UTI) in hospitalized patients were determined by collecting consecutive isolates over a specified period of time, as part of the SENTRY Antimicrobial Resistance Surveillance Program (SENTRY). All isolates were tested by reference broth microdilution. RESULTS AND CONCLUSIONS: A total of 3,728 bacterial strains were obtained from January, 1997, to December, 1999, from 12 Brazilian hospitals located in 4 states. The largest number of isolates were obtained from patients with BSI (2,008), followed by LRTI (822 cases), UTI (468 cases), and WSSTI (430 cases). Staphylococcus aureus was the most frequently isolated pathogen in general (22.8% - 852 isolates), followed by E. coli (13.8% - 516 cases) and Pseudomonas aeruginosa (13.3% - 496 cases). Staphylococcus aureus was also the most common species isolated from BSI (23.6%) and WSSTI (45.8%), and P. aeruginosa was the most frequent species isolated from patients with LRTI (29.4%). The main bacterial resistance problems found in this study were: imipenem resistance among P. aeruginosa (69.8% susceptibility) and Acinetobacter spp. (88.1% susceptibility); ESBL production among K. pneumoniae (48.4%) and E. coli (8.9%); resistance to third generation cephalosporins among Enterobacter spp. (68.1% susceptible to ceftazidime) and oxacillin resistance among S. aureus (34.0%) and coagulase negative staphylococci (80.1%). Only the carbapenems (88.1% to 89.3% susceptibility) showed reasonable activity against the Acinetobacter spp. isolates evaluated.
Asunto(s)
Antibacterianos/farmacología , Infección Hospitalaria/epidemiología , Farmacorresistencia Microbiana , Bacterias Gramnegativas/efectos de los fármacos , Infecciones por Bacterias Gramnegativas/epidemiología , Brasil/epidemiología , Infección Hospitalaria/microbiología , Bacterias Gramnegativas/aislamiento & purificación , Infecciones por Bacterias Gramnegativas/microbiología , Hospitales , Humanos , Control de Infecciones/organización & administración , Pruebas de Sensibilidad Microbiana , Prevalencia , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificaciónRESUMEN
One thousand seventy-three bacterial isolates were collected from patients with community acquired respiratory tract infections (CARTI) in 11 Latin American centers (7 countries) during 1997 and 1998. They were tested against numerous antimicrobial agents by the reference broth microdilution method as part of the ongoing multinational SENTRY Antimicrobial Surveillance Program. Among Streptococcus pneumoniae (553 isolates), approximately 61% were susceptible to penicillin. There was a great variation of the penicillin susceptibility rates among participating countries. The highest susceptibility rates were found in Argentina (76.7%) and Brazil (71.9%), while the lowest rate of penicillin susceptibility was detected in Mexico (33.3%). High level resistance to penicillin and resistance to cefotaxime were observed in nearly 10% of the isolates. The newer quinolones, levofloxacin (MIC(90) 2 microg/mL) and gatifloxacin (MIC90 0.5 microg/mL), were active against 100% of the isolates tested. Among the other non-beta-lactams drugs tested, the rank order of susceptibility against the pneumococci was: chloramphenicol (93.9%)>clindamycin (93.2%)> azithromycin (89.1%) > clarithromycin (88.7%)>tetracycline (78.5%)> trimethoprim/sulfamethoxazole (55.7%). The percentage of Haemophilus influenzae (361 isolates) isolates resistant to amoxicillin was 12. 7% (beta-lactamase positive). Among Moraxella catarrhalis (159 isolates) isolates, only 8.2% were susceptible. Clavulanic acid restored the activity of amoxicillin against both species. Trimethoprim/sulfamethoxazole was active against only 59.5% of H. influenzae, while susceptibility to this compound among M. catarrhalis was 96.1%. All other compounds tested were active against>95% of H. influenzae and M. catarrhalis isolates. These species were susceptible to levofloxacin (MIC90 < or = 0.5 microg/mL for both) and gatifloxacin (MIC90 < or = 0.03 microg/mL for both) with very low MICs. Our results indicate that penicillin resistance rates are particularly high among pneumococci in some countries. The newer fluoroquinolones show an excellent potency and spectrum against pathogens causing community acquired respiratory infections in Latin America.
Asunto(s)
Antibacterianos/farmacología , Infecciones Bacterianas/microbiología , Haemophilus influenzae/efectos de los fármacos , Moraxella catarrhalis/efectos de los fármacos , Infecciones del Sistema Respiratorio/microbiología , Streptococcus pneumoniae/efectos de los fármacos , Infecciones Comunitarias Adquiridas/microbiología , Farmacorresistencia Microbiana , Haemophilus influenzae/aislamiento & purificación , Humanos , América Latina , Pruebas de Sensibilidad Microbiana/métodos , Moraxella catarrhalis/aislamiento & purificación , Prevalencia , Vigilancia de Guardia , Streptococcus pneumoniae/aislamiento & purificaciónRESUMEN
Modern epidemiology studies now require that nosocomial pathogens be characterized to the subspecies level whenever possible to better define infectious processes and modes of transmission. In general, if isolates are classified as different by at least one molecular typing method, they may be assumed to represent different strains and to reflect independent infections. If the isolates are the same, it may be assumed that cross infection has occurred or that the patients were infected by exposure to a common source. Typing methods may also be used to address clinical problems related to distinguishing reinfection versus relapse of an infection, and to examine the development of antifungal resistance among fungal pathogens during the course of antifungal therapy. Determining DNA fingerprints of sequential isolates from patients undergoing antifungal therapy has been useful in demonstrating the potential for the development of antifungal resistance in previously susceptible strains and for detecting the substitution of a more resistant strain for a more susceptible strain in the face of intense antimicrobial pressure. In order to be useful as an epidemiological typing method, a DNA fingerprinting system must effectively distinguish between genetically unrelated strains, identify the same strain in separate samples, and reflect genetic relatedness or unrelatedness (genetic distance) among strains.
Asunto(s)
Candida/genética , Candidiasis/epidemiología , Infección Hospitalaria/epidemiología , Candida/aislamiento & purificación , Candidiasis/microbiología , Candidiasis/prevención & control , Candidiasis/transmisión , Infección Hospitalaria/microbiología , Infección Hospitalaria/prevención & control , Infección Hospitalaria/transmisión , Dermatoglifia del ADN , Farmacorresistencia Microbiana , Humanos , Epidemiología MolecularRESUMEN
The establishment of a standardized broth reference method for antifungal susceptibility testing of yeasts has opened the door to a number of interesting and useful developments. The adaptation of the reference macrodilution method to a microdilution method has significantly increased the clinical utility of antifungal susceptibility testing, and both methods are now included in the NCCLS document M27-A. The publication of quality control limits for five antifungal agents, coupled with the establishment of interpretive MIC breakpoints for three agents, provides useful parameters to survey clinical isolates of Candida and other yeast species. Adaptations of the M27 microdilution method for testing molds has also proved feasible. These developments have made it possible for a number of recent studies designed to expand the capabilities of laboratories to perform antifungal susceptibility testing and to enhance our understanding of trends in antifungal susceptibility. The availability of reference methods also provides a useful touchstone for the development of commercial products that promise to be more user friendly and to further improve test standardization. Products in varying stages of development include two colorimetric microdilution methods (Sensititre and KPI) and the Etest stable gradient MIC method. Preliminary data indicate that these methods are viable alternatives to the reference method for testing of yeasts. Furthermore, Etest may also prove useful for testing molds. Future expectations for antifungal susceptibility testing includes improved ability to detect amphotericin B resistance, development of an NCCLS document for susceptibility testing of molds, and application of these methods for testing dermatophytes. Incorporation of antifungal susceptibility testing methods into the clinical trials of new antifungal agents will facilitate the establishment of clinical correlates and further enhance the clinical utility of antifungal susceptibility testing.
Asunto(s)
Antifúngicos/farmacología , Hongos/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/normas , Farmacorresistencia Microbiana , Humanos , Pruebas de Sensibilidad Microbiana/métodosRESUMEN
Gemifloxacin (GEMI), formerly SB-265805 and LB20304, is a newer fluoroquinolone with broad-spectrum activity against a wide variety of bacterial pathogens. The present investigation extended earlier observations by sampling an additional 6790 gram-positive organisms from more than 50 medical centres on three continents. The reference broth microdilution method with recommended medium supplements was used throughout. Selected results (number strains tested; MIC90 for GEMI/trovafloxacin in mg/l; % < or = 1 mg/l for GEMI/trovafloxacin) were: Staphylococcus aureus (3672; 2/2; 86/85), S. epidermidis (404; 1/>4; 92/71), Enterococcus faecalis (630; 4/>4; 76/66), E. faecium (216; > 4/>4; 15/11), Streptococcus pneumoniae (300; 0.06/0.25; 100/97), beta-haemolytic streptococci (150; 0.06/0.25; 100/100) and viridans group streptococci (150; 0.12/0.25; 99/97). Gemifloxacin appeared equal or superior to trovafloxacin in its overall gram-positive spectrum of activity pending a choice of the susceptible breakpoint concentration. Continued in vitro, pharmacodynamic and clinical investigations of gemifloxacin appear warranted.
Asunto(s)
Antiinfecciosos/farmacología , Fluoroquinolonas , Bacterias Grampositivas/efectos de los fármacos , Naftiridinas/farmacología , Europa (Continente) , Gemifloxacina , Infecciones por Bacterias Grampositivas/epidemiología , Infecciones por Bacterias Grampositivas/microbiología , Humanos , Pruebas de Sensibilidad Microbiana , América del Norte , América del SurRESUMEN
The minimum inhibitory concentrations of six broad-spectrum beta-lactam antimicrobial agents were determined in 1998 by use of the Etest versus a total of 502 bacteria in seven Venezuelan hospital laboratories. These data were compared with results of a similar study performed in 1997. The organisms tested included 309 recent clinical isolates of Enterobacteriaceae, 70 Pseudomonas aeruginosa, 54 Acinetobacter species, and 69 oxacillin-susceptible Staphylococcus aureus. Extended spectrum beta-lactamase production was noted among 30% of Klebsiella pneumoniae isolates. Hyperproduction of Amp C cephalosporinase producing resistance to ceftazidime and cefotaxime was observed with 10 to 37% of isolates of Enterobacter spp., Serratia spp., and Citrobacter freundii. The overall rank order of activity of the six beta-lactams tested in this study against all clinical isolates was imipenem (96.6% susceptible) > cefepime (90.4%) > piperacillin/tazobactam (85.7%) > ceftazidime (73.5%) > cefotaxime (70.5%) > piperacillin (55.0%). These findings were very similar to those reported for 1997.
Asunto(s)
Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Cefalosporinasa/biosíntesis , Farmacorresistencia Microbiana , Enterobacteriaceae/efectos de los fármacos , Staphylococcus/efectos de los fármacos , Factores de Tiempo , Venezuela , beta-LactamasRESUMEN
The minimum inhibitory concentrations of six broad-spectrum beta-lactam antimicrobial agents were determined in 1998 by use of the Etest versus a total of 823 bacteria in 11 Colombian hospital laboratories. These data were compared with results of a similar study conducted in 1997. The organisms tested included 532 recent clinical isolates of Enterobacteriaceae, 108 Pseudomonas aeruginosa, 94 Acinetobacter species, and 89 oxacillin-susceptible Staphylococcus aureus. Extended-spectrum beta-lactamase production was noted among 27.8 to 33.9% of Escherichia coli isolates and 41.7 to 46.7% of Klebsiella spp. isolates. Hyperproduction of Amp C cephalosporinases was observed with 10.5 to 31.4% of isolates of Enterobacter spp., Serratia spp., and Citrobacter spp. An increase in resistance to all of the beta-lactams was observed among Enterobacteriaceae, Acinetobacter spp. and P. aeruginosa when 1998 results were compared with those obtained in 1997. The overall rank order of activity of the six beta-lactams tested in 1998 versus all clinical isolates was imipenem (93.2% susceptible) > cefoperazone/sulbactam (84.1%) > cefepime (80.9%) > ceftazidime (70.7%) > aztreonam (65.7%) > cefotaxime (65.6%). In contrast, the rank order of these same agents tested against a similar collection of Colombian isolates in 1997 was imipenem (96.6% susceptible) > cefepime (93.6%) > cefoperazone/sulbactam (90.5%) > cefotaxime (74.9%) > aztreonam (74.3%) > ceftazidime (73.2%).
Asunto(s)
Bacterias Gramnegativas/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Resistencia betalactámica , beta-Lactamas/farmacología , Colombia , Infecciones por Bacterias Gramnegativas/microbiología , Humanos , Recién Nacido , Laboratorios de Hospital , Pruebas de Sensibilidad Microbiana/métodos , Oxacilina/farmacología , Penicilinas/farmacología , Infecciones Estafilocócicas/microbiologíaRESUMEN
An international program of surveillance of bloodstream infections (BSIs) in the United States, Canada, and South America between January and December 1997 detected 306 episodes of candidemia in 34 medical centers (22 in the United States, 6 in Canada, and 6 in South America). Eighty percent of the BSIs were nosocomial and 50% occurred in patients hospitalized in an intensive care unit. Overall, 53.3% of the BSIs were due to Candida albicans, 15.7% were due to C. parapsilosis, 15.0% were due to C. glabrata, 7.8% were due to C. tropicalis, 2.0% were due to C. krusei, 0.7% were due to C. guilliermondii, and 5.8% were due to Candida spp. However, the distribution of species varied markedly by country. In the United States, 43.8% of BSIs were due to non-C. albicans species. C. glabrata was the most common non-C. albicans species in the United States. The proportion of non-C. albicans BSIs was slightly higher in Canada (47.5%), where C. parapsilosis, not C. glabrata, was the most common non-C. albicans species. C. albicans accounted for 40.5% of all BSIs in South America, followed by C. parapsilosis (38.1%) and C. tropicalis (11.9%). Only one BSI due to C. glabrata was observed in South American hospitals. Among the different species of Candida, resistance to fluconazole (MIC, > or = 64 microg/ml) and itraconazole (MIC, > or = 1.0 microg/ml) was observed with C. glabrata and C. krusei and was observed more rarely among other species. Isolates of C. albicans, C. parapsilosis, C. tropicalis, and C. guilliermondii were all highly susceptible to both fluconazole (99.4 to 100% susceptibility) and itraconazole (95.8 to 100% susceptibility). In contrast, 8.7% of C. glabrata isolates (MIC at which 90% of isolates are inhibited [MIC90], 32 microg/ml) and 100% of C. krusei isolates were resistant to fluconazole, and 36.9% of C. glabrata isolates (MIC90, 2.0 microg/ml) and 66.6% of C. krusei isolates were resistant to itraconazole. Within each species there were no geographic differences in susceptibility to fluconazole or itraconazole.
Asunto(s)
Antifúngicos/farmacología , Candida/efectos de los fármacos , Candidiasis/epidemiología , Fungemia/epidemiología , Canadá/epidemiología , Candida/clasificación , Candida/aislamiento & purificación , Candidiasis/microbiología , Fluconazol/farmacología , Fungemia/microbiología , Humanos , Cooperación Internacional , Itraconazol/farmacología , Pruebas de Sensibilidad Microbiana , Vigilancia de Guardia , América del Sur/epidemiología , Estados Unidos/epidemiologíaRESUMEN
The minimum inhibitory concentrations of 6 broad-spectrum beta-lactam antimicrobial agents were determined by use of the Etest versus a total of 569 bacteria in 7 Puerto Rican hospital laboratories. These included 342 recent clinical isolates of Enterobacteriaceae, 63 Pseudomonas aeruginosa, 54 Acinetobacter species, and 110 oxacillin-susceptible staphylococci. Extended spectrum beta-lactamase production was noted among 11% of Klebsiella pneumoniae isolates. Hyperproduction of Amp C cephalosporinase was observed with > 20% of isolates of Enterobacter spp., Serratia spp., and Citrobacter freundii. The overall rank order of activity of the six beta-lactams examined in this study versus all clinical isolates was imipenem (95.8% susceptible) > cefepime (91.1%) > piperacillin/ tazobactam (82.3%) > cefotaxime (77.6%) > piperacillin (72.5%) > ceftazidime (67.0%).
Asunto(s)
Antibacterianos , Antibacterianos/análisis , Estudios Transversales , Farmacorresistencia Microbiana , Bacilos y Cocos Aerobios Gramnegativos/efectos de los fármacos , Bacilos y Cocos Aerobios Gramnegativos/aislamiento & purificación , Cocos Grampositivos/efectos de los fármacos , Cocos Grampositivos/aislamiento & purificación , Humanos , Pruebas de Sensibilidad Microbiana , Puerto Rico , beta-LactamasRESUMEN
In early 1997, a 15-laboratory surveillance project was initiated in Venezuela to monitor the potency and spectrum of 6 broad-spectrum antimicrobial agents (cefepime, cefotaxime, ceftazidime, piperacillin, piperacillin/tazobactam, and imipenem) tested against approximately 100 organisms per participant center (1297 strains). Ten groups of organisms were tested by the Etest method (AB BIODISK, Solna, Sweden) with results validated by concurrent quality control strain analysis. Results from all centers were tabulated and 96.3% of quality assurance tests were within ranges recommended by the National Committee for Clinical Laboratory Standards. Among the six beta-lactam class drugs tested, imipenem and cefepime were the most active against all isolates tested. Overall, the rank order of susceptibility of the six agents was imipenem (97.2%, susceptible; MIC90 2 micrograms/ml) > cefepime (92.8%; MIC90 6 micrograms/mL) > piperacillin/tazobactam (77.2-83.0%; MIC90 > 256 micrograms/mL) > cefotaxime (72.2%; MIC90 > 256 micrograms/mL) > piperacillin (56.8-65.8%; MIC90 > 256 micrograms/mL) > ceftazidime (64.66%; MIC90 128 micrograms/mL). Both cefepime and imipenem were active against ceftazidime-resistant strains of Enterobactericaeae as well as against Pseudomonas aeruginosa and oxacillin-susceptible staphylococci. Resistance phenotypes consistent with extended spectrum beta-lactamases (ESBLs) and stably derepressed Bush group 1 cephalosporinases were documented in strains of Klebsiella spp. and Enterobacters, respectively. These data should be used to guide empiric therapy with beta-lactams in Venezuela, and additionally will provide a reference statistical baseline to which future studies in this nation can be compared.
Asunto(s)
Antibacterianos/farmacología , Enterobacteriaceae/efectos de los fármacos , Bacilos y Cocos Aerobios Gramnegativos/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Staphylococcus aureus/efectos de los fármacos , Acinetobacter/efectos de los fármacos , Farmacorresistencia Microbiana , Resistencia a Múltiples Medicamentos , Enterobacteriaceae/enzimología , Humanos , Resistencia a la Meticilina , Pseudomonas aeruginosa/efectos de los fármacos , Control de Calidad , Reproducibilidad de los Resultados , Venezuela , beta-Lactamasas/biosíntesis , beta-LactamasRESUMEN
Gatifloxacin (formerly AM-115) is a new 8-methoxy fluoroquinolone with an expanded spectrum against Gram-positive cocci and some anaerobes. To assess this new agent's activity, a collection of 1,676 Gram-positive cocci were selected for resistance to ciprofloxacin (> or = 4 micrograms/mL) and tested against gatifloxacin and 18 other compounds by reference broth microdilution methods. The strains (approximately 23,000 total isolates from the SENTRY Antimicrobial Surveillance Program) were from significant blood stream, respiratory tract, wound, and urinary tract infections in patients in North (38 hospitals) and South (10 hospitals) America. Against Enterococcus faecalis and E. faecium, gatifloxacin inhibited only 16% and 10% of strains compared with 12% and 5% for recently released trovafloxacin, respectively. Among Staphylococcus aureus (90% oxacillin-resistant) strains, gatifloxacin was more active (67% susceptible at < or = 4 micrograms/mL) than trovafloxacin (59%) or sparfloxacin (4%). Gatifloxacin had a wider spectrum than trovafloxacin against coagulase-negative staphylococci especially S. epidermidis, 2% versus 58% resistance. The glycopeptides, chloramphenicol and rifampin were most active. Against all genus/species groups with more than 100 sample strains (1,566), high-level resistance to gatifloxacin and trovafloxacin (> 4 micrograms/mL) was not significantly different (41.7% versus 39.1%; p > 0.05). Emerging resistance to the fluoroquinolones remains a clinical problem among Gram-positive species, and gatifloxacin seems to be active in vitro against many of these contemporary strains isolated in the Americas.
Asunto(s)
Antiinfecciosos/farmacología , Ciprofloxacina/farmacología , Fluoroquinolonas , Infecciones por Bacterias Grampositivas/microbiología , Cocos Grampositivos/efectos de los fármacos , Antituberculosos/farmacología , Técnicas Bacteriológicas , Farmacorresistencia Microbiana , Gatifloxacina , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Humanos , Pruebas de Sensibilidad Microbiana , Naftiridinas/farmacología , América del Norte , Quinolonas/farmacología , América del SurRESUMEN
Pneumonia is the most common fatal hospital-acquired infection, with attributable mortality rates ranging from 30 to 60%. Rapid initiation of optimal antimicrobial therapy is essential for obtaining treatment success. In this report the antimicrobial susceptibility of 556 strains from the lower respiratory tract were collected by the SENTRY Antimicrobial Surveillance Program (1997). These strains were isolated from hospitalized patients with pneumonia in 10 Latin American centers (6 countries) as part of this 68-center worldwide program. The isolates were susceptibility tested against more than 70 drugs (35 reported) by the reference broth microdilution method. Klebsiella pneumoniae and Escherichia coli phenotypically consistent with extended spectrum beta-lactamase (ESBL) production were characterized further by ribotyping and pulsed-field gel electrophoresis. The five most frequently isolated species were (n/%): Pseudomonas aeruginosa (149/26.8%), Staphylococcus aureus (127/22.8%), Acinetobacter spp. (66/11.9%), Klebsiella spp. (56/10.1%), and Enterobacter spp. (40/7.2%). P. aeruginosa demonstrated high rates of resistance to a majority of the antimicrobial drugs tested. Carbapenems, amikacin, and piperacillin/tazobactam demonstrated the highest susceptibility rates (73.8-77.2%) against P. aeruginosa, however the lowest resistance rate was observed for cefepime (6.7%). Acinetobacter spp. also showed very high rates of resistance and the most active compounds were imipenem and meropenem (89.0% susceptibility) followed by the tetracyclines. Cephalosporin susceptibilities among Klebsiella spp. were low: cefoxitin, 73.0%; ceftazidime, 69.4%; and ceftriaxone, 65.9%. Approximately 37% and 28% of K. pneumoniae and E. coli isolates, respectively, were considered ESBL producers based on NCCLS criteria. Ceftriaxone was active against only 52.5% of Enterobacter spp. isolates, whereas cefepime was active against 90.0% of isolates (MIC50, < or = 0.12 microgram/mL). Oxacillin resistance was detected in nearly 50% of S. aureus isolates. The most active drugs against S. aureus were vancomycin, teicoplanin, and quinupristin/dalfopristin (MIC90, 1 microgram/mL). In summary, our study of pneumonias in Latin American medical centers demonstrated a greatly increased prevalence of Acinetobacter spp. and higher resistance rates among Gram-negative bacilli when compared with similar controlled studies from North America.
Asunto(s)
Antibacterianos/farmacología , Neumonía/microbiología , Bacterias/efectos de los fármacos , Bacterias/genética , Humanos , América Latina , Pruebas de Sensibilidad MicrobianaRESUMEN
The need for comprehensive and quantitative accurate antimicrobial resistance surveillance systems has become acute as a guide to problem recognition and to focus local interventions. A multilaboratory (10 medical centers) Colombia surveillance project was initiated in early 1997 to monitor the potency and spectrum of six (cefepime, cefotaxime, ceftazidime, cefoperazone/sulbactam, aztreonam, and imipenem) broad-spectrum antimicrobial agents tested against 100 organisms per participant center (802 strains). Ten groups of organisms were tested by a reference-quality method (Etest; AB BIODISK, Solna, Sweden) with results validated by concurrent quality control and additional challenge strain analysis. Results from nine qualifying medical centers were tabulated, and 95.7 to 96.8% of quality assurance tests were within expected ranges. Only cefepime (90.1-100.0% susceptible) and imipenem (96.3-100.0%) were active against all Enterobacteriaceae at > 90% of susceptible isolates using the breakpoint concentrations recommended by the National Committee for Clinical Laboratory Standards. Among ceftazidime- (or cefotaxime- or aztreonam-) resistant Enterobacter spp. and Citrobacter freundii, cefepime remained active, but not cefoperazone with sulbactam. Escherichia coli and Klebsiella spp. strains having resistance phenotypes consistent with extended spectrum beta-lactamase production were discovered in approximately 5 to 10% of isolates. All tested drugs except ceftazidime (31.8-57.7% susceptible) were active against > 94% of oxacillin-susceptible staphylococci. Similar rates of resistance (9.1-14.8%) were observed in Pseudomonas aeruginosa for five of six drugs (not cefotaxime; 15.9% of strains were susceptible). Acinetobacter spp. isolates were most susceptible to imipenem (95.8%), cefepime (86.1%), and cefoperazone/sulbactam (83.3%). Overall for the 1997 order of antimicrobial spectrums for these tested compounds was: imipenem (96.6%) > cefepime (93.6%) > cefoperazone/sulbactam (90.5%) > cefotaxime (74.9%) > aztreonam (74.3% for Gram-negative bacilli only) > ceftazidime (73.2%). These data should be used to guide empiric regimens in Colombia, and additionally will provide a resistance statistical baseline to which future studies in this nation can be compared.
Asunto(s)
Antibacterianos/farmacología , Enterobacteriaceae/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Staphylococcus/efectos de los fármacos , Resistencia betalactámica/fisiología , Aztreonam/farmacología , Cefepima , Cefoperazona/farmacología , Cefotaxima/farmacología , Ceftazidima/farmacología , Cefalosporinasa/biosíntesis , Cefalosporinas/farmacología , Estudios de Cohortes , Colombia , Enterobacteriaceae/enzimología , Humanos , Imipenem/farmacología , Pruebas de Sensibilidad Microbiana , Reproducibilidad de los Resultados , Sulbactam/farmacologíaRESUMEN
Fungal arthritis in pediatric patients is rare and is most often associated with hematogenous spread to the affected joint. It is generally seen concomitant with, or shortly after, fungemia. We report a case of an immunocompetent patient in whom candidal arthritis developed 1 year after initial fungemia. The initial candidiasis was considered to be adequately treated with amphotericin B. The Candida isolates from the neonatal fungemia and subsequent arthritis were the some as identified by electrophoretic karyotype, restriction fragment length polymorphism analysis, and antifungal susceptibility testing. Pediatric candidal fungemia, arthritis, and their treatments are discussed.
Asunto(s)
Artritis Infecciosa/microbiología , Candida albicans , Fungemia/complicaciones , Anfotericina B/uso terapéutico , Antifúngicos/uso terapéutico , Candida albicans/aislamiento & purificación , Femenino , Fungemia/tratamiento farmacológico , Fungemia/microbiología , Humanos , Recién Nacido , Cariotipificación , Pruebas de Sensibilidad Microbiana , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
We evaluated the spread of Acinetobacter baumannii strains among three hospitals located in São Paulo, Brazil. A total of 46 isolates, which were typed by chromosomal DNA analysis with use of pulsed field gel electrophoresis (PFGE), were tested for susceptibility to the fluoroquinolones, carbapenems, aminoglycosides (amikacin), cephalosporins, polymyxin B, and ampicillin/sulbactam by means of the broth microdilution method, disk diffusion, and the E-test. Isolates with an identical PFGE pattern (pattern B) that were susceptible only to carbapenems, polymyxin B, and ampicillin/ sulbactam were recovered in all three hospitals. In addition, isolates with PFGE pattern A that were susceptible only to polymyxin B and ampicillin/sulbactam were recovered in hospitals 1 and 2. The results of our study strongly suggest the interhospital transmission of multiresistant epidemic strains of A. baumannii in São Paulo. Once in the hospital, these strains can disseminate and cause outbreaks with devastating consequences.
Asunto(s)
Infecciones por Acinetobacter/microbiología , Acinetobacter/efectos de los fármacos , Infección Hospitalaria/microbiología , ADN Bacteriano/análisis , Farmacorresistencia Microbiana , Resistencia a Múltiples Medicamentos , Acinetobacter/genética , Infecciones por Acinetobacter/tratamiento farmacológico , Brasil , Infección Hospitalaria/tratamiento farmacológico , Electroforesis en Gel de Campo Pulsado , Humanos , Pruebas de Sensibilidad MicrobianaRESUMEN
The ability to identify specific strains within a given species of pathogen is an important aid in the rational development of effective measures to prevent and control nosocomial infections. The efforts of both microbiologist and hospital epidemiologic are facilitated greatly by the availability of the newer molecular epidemiologic typing techniques. Although these methods clearly have limitations, they generally are a significant improvement over the more conventional typing methods, many of which are too cumbersome, insensitive, and time-consuming to be of practical value for epidemiologic evaluations. Based on current experience, the molecular typing methods that appear to be the most practical and useful for both large and small scale epidemiologic studies are the DNA-based methods of REAP and PFGE. Many questions remain concerning the appropriate role of molecular typing methods in the clinical microbiology laboratory. Often, molecular typing may be performed more efficiently in a reference laboratory. In contrast, selected methods such as plasmid analysis are well within the scope of clinical microbiology laboratories and may be an important adjunct to the hospital infection control effort. Given the limitations of the available methods and the complex nature of patients at risk for nosocomial infections, it is imperative that these methods be employed with clear epidemiologic objectives in mind. Typing should always include unrelated as well as epidemiologically related isolates and, whenever possible, all organisms should be typed under identical conditions, preferably within the same test run. In addition, results are most effectively used to supplement rather than to replace hypotheses and questions thoughtfully developed by the clinician or epidemiologist. Ideally, typing is performed independently by the laboratory to avoid bias, but the results are applied collaboratively to ensure that both the potential insights and the unavoidable ambiguities presented by the results are clearly appreciated. Additional studies based upon sound epidemiologic principles will help clarify the role of the various molecular typing methods as epidemiologic markers and advance our understanding of the epidemiology of nosocomial infections.