RESUMEN
CDC weak oxidizer group 2 (WO-2) consists of nine phenotypically similar human clinical isolates received by the Centers for Disease Control and Prevention between 1989 and 1998. Four of the isolates were from blood, three were from sputum, and one each was from bronchial fluid and maxillary sinus. All are aerobic nonfermentative, motile gram-negative rods with one to eight polar flagella per cell. All grew at 25 and 35 degrees C and were positive for catalase, urease (usually delayed 3 to 7 days), citrate, alkalinization of litmus milk, oxidization of glycerol (weakly), and growth on MacConkey agar and in nutrient broth without NaCl. All except one strain were oxidase positive with the Kovács method, and all except one isolate weakly oxidized D-glucose. All were negative for oxidation of D-xylose, D-mannitol, lactose, sucrose, maltose, and 20 other carbohydrates, esculin hydrolysis, indole production, arginine dihydrolase, and lysine and ornithine decarboxylase. Only two of nine isolates reduced nitrate. Broth microdilution susceptibilities were determined for all strains against 13 antimicrobial agents. Most of the strains were resistant to ampicillin, extended-spectrum cephalosporins, and aminoglycosides, including gentamicin, tobramycin, and amikacin, but they varied in their susceptibility to fluoroquinolones. High-performance liquid chromatographic and mass spectrometric analyses of the WO-2 group identified ubiquinone-8 as the major quinone component. The percent G+C of the WO-2 strains ranged from 65.2 to 70.7% (thermal denaturation method). All shared a common cellular fatty acid (CFA) profile, which was characterized by relatively large amounts (7 to 22%) of 16:1omega7c, 16:0, 17:0cyc, 18:1omega7c, and 19:0cyc(11-12); small amounts (1 to 3%) of 12:0 and 14:0; and eight hydroxy acids, 2-OH-12:0 (4%), 2-OH-14:0 (trace), 3-OH-14:0 (12%), 2-OH-16:1 (1%), 2-OH-16:0 (3%), 3-OH-16:0 (4%), 2-OH-18:1 (2%), and 2-OH-19:0cyc (3%). This profile is similar to the CFA profile of Pandoraea, a recently described genus associated with respiratory infections in cystic fibrosis patients (T. Coenye et al., Int. J. Syst. Evol. Microbiol., 50:887-899, 2000). Sequencing of the 16S rRNA gene (1,300 bp) for all nine strains indicated a high level (> or =98.8%) of homogeneity with Pandoraea spp. type strains. DNA-DNA hybridization analysis (hydroxyapatite method; 70 degrees C) confirmed the identity of WO-2 with the genus Pandoraea and assigned three strains to Pandoraea apista and three to Pandoraea pnomenusa, and identified three additional new genomospecies containing one strain each (ATCC BAA-108, ATCC BAA-109, ATCC BAA-110). This study also shows that Pandoraea isolates may be encountered in blood cultures from patients without cystic fibrosis.
Asunto(s)
Betaproteobacteria/clasificación , Infecciones por Bacterias Gramnegativas/microbiología , Anciano , Antibacterianos/farmacología , Técnicas de Tipificación Bacteriana , Betaproteobacteria/química , Betaproteobacteria/efectos de los fármacos , Betaproteobacteria/genética , Preescolar , Ácidos Grasos/análisis , Femenino , Genes de ARNr , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Datos de Secuencia Molecular , Oxidación-Reducción , Fenotipo , Quinonas/análisis , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
Between 1983 and 1994, 13 phenotypically similar unidentified clinical isolates were received by the Special Bacteriology Reference Laboratory, Centers for Disease Control and Prevention (CDC). Sources included blood (four strains), lung (three strains), knee fluid and duodenal tissue (one strain each), bone, and lymph node tissue (two strains each). All were aerobic glucose-oxidizing, slender, long, curved gram-negative rods that utilized xylose, sucrose, and maltose; did not grow on MacConkey agar in 1 to 2 days; were oxidase positive; hydrolyzed esculin; and grew on Campylobacter selective medium. All were negative for urease, indole, nitrate reduction, and gelatin hydrolysis. All were motile by means of a single polar flagellum with a noticeably short wavelength; however, motility was sometimes difficult to demonstrate. The cellular fatty acid compositions of these strains, as analyzed by gas-liquid chromatography, were unique, characterized by relatively large amounts of 16:1omega7c, 16:0, and 18:1omega7c with smaller amounts of 12:0, 3-OH-12:1, 14:0, 15:0, 18:0, Br-19:1, and 19:0cyc11-12. High-performance liquid chromatography and mass spectrometry of the quinone extracts of three representative strains showed ubiquinone-10 as the major component. Based on the breakpoints for the family Enterobacteriaceae, all the strains were susceptible in vitro to aminoglycosides, sulfamethoxazole-trimethoprim, and chloramphenicol but were resistant to most beta-lactams except imipenem. The MICs of amoxicillin-clavulanate and ciprofloxacin for these strains clustered around the breakpoints, which makes it difficult to predict the strains' response in vivo to these agents. This group has been designated CDC oxidizer group 3 (O-3).