24 research outputs found
Analysis of antibiotic resistance genes in multidrug-resistant acinetobacter sp. isolates from military and civilian patients treated at the Walter Reed Army Medical Center
Military medical facilities treating patients injured in Iraq and Afghanistan have identified a large number of multidrug-resistant (MDR) Acinetobacter baumannii isolates. In order to anticipate the impact of these pathogens on patient care, we analyzed the antibiotic resistance genes responsible for the MDR phenotype in Acinetobacter sp. isolates collected from patients at the Walter Reed Army Medical Center (WRAMC). Susceptibility testing, PCR amplification of the genetic determinants of resistance, and clonality were determined. Seventy-five unique patient isolates were included in this study: 53% were from bloodstream infections, 89% were resistant to at least three classes of antibiotics, and 15% were resistant to all nine antibiotics tested. Thirty-seven percent of the isolates were recovered from patients nosocomially infected or colonized at the WRAMC. Sixteen unique resistance genes or gene families and four mobile genetic elements were detected. In addition, this is the first report of blaOXA-58-like and blaPER-like genes in the U.S. MDR A. baumannii isolates with at least eight identified resistance determinants were recovered from 49 of the 75 patients. Molecular typing revealed multiple clones, with eight major clonal types being nosocomially acquired and with more than 60% of the isolates being related to three pan-European types. This report gives a “snapshot” of the complex genetic background responsible for antimicrobial resistance in Acinetobacter spp. from the WRAMC. Identifying genes associated with the MDR phenotype and defining patterns of transmission serve as a starting point for devising strategies to limit the clinical impact of these serious infections. © 2006, American Society for Microbiolog
Diversity analysis of cotton (Gossypium hirsutum L.) germplasm using the CottonSNP63K Array
Cotton germplasm resources contain beneficial alleles that can be exploited to develop germplasm adapted to emerging environmental and climate conditions. Accessions and lines have traditionally been characterized based on phenotypes, but phenotypic profiles are limited by the cost, time, and space required to make visual observations and measurements. With advances in molecular genetic methods, genotypic profiles are increasingly able to identify differences among accessions due to the larger number of genetic markers that can be measured. A combination of both methods would greatly enhance our ability to characterize germplasm resources. Recent efforts have culminated in the identification of sufficient SNP markers to establish high-throughput genotyping systems, such as the CottonSNP63K array, which enables a researcher to efficiently analyze large numbers of SNP markers and obtain highly repeatable results. In the current investigation, we have utilized the SNP array for analyzing genetic diversity primarily among cotton cultivars, making comparisons to SSR-based phylogenetic analyses, and identifying loci associated with seed nutritional traits. (Résumé d'auteur
Overcoming Resistance to β-Lactamase Inhibitors: Comparing Sulbactam to Novel Inhibitors against Clavulanate Resistant SHV Enzymes with Substitutions at Ambler Position 244 â€
Development of a Multiplex PCR-Ligase Detection Reaction Assay for Diagnosis of Infection by the Four Parasite Species Causing Malaria in Humans
The diagnosis of infections caused by Plasmodium species is critical for understanding the nature of malarial disease, treatment efficacy, malaria control, and public health. The demands of field-based epidemiological studies of malaria will require faster and more sensitive diagnostic methods as new antimalarial drugs and vaccines are explored. We have developed a multiplex PCR-ligase detection reaction (LDR) assay that allows the simultaneous diagnosis of infection by all four parasite species causing malaria in humans. This assay exhibits sensitivity and specificity equal to those of other PCR-based assays, identifying all four human malaria parasite species at levels of parasitemias equal to 1 parasitized erythrocyte/ÎĽl of blood. The multiplex PCR-LDR assay goes beyond other PCR-based assays by reducing technical procedures and by detecting intraindividual differences in species-specific levels of parasitemia. Application of the multiplex PCR-LDR assay will provide the sensitivity and specificity expected of PCR-based diagnostic assays and will contribute new insight regarding relationships between the human malaria parasite species and the human host in future epidemiological studies
Crystal Structure of KPC-2: Insights into Carbapenemase Activity in Class A β-Lactamases â€
Long-term health-related quality of life following esophagectomy: A nonrandomized comparison of thoracoscopically assisted and open surgery
Objective: The aim of this study was to assess long-term health-related quality of life (HRQL) in patients after thoracoscopic and open esophagectomy. Summary of Background Data: Trials comparing minimally invasive with open transthoracic esophagectomy have shown improved short-term outcomes; however, long-term HRQL data are lacking. This prospective nonrandomized study compared HRQL and survival after thoracoscopically assisted McKeown esophagectomy (TAMK) and open transthoracic Ivor Lewis esophagectomy (TTIL) for esophageal or gastroesophageal junction (GEJ) cancer. Methods: Patients with esophageal or GEJ cancer selected for TAMK or TTIL completed baseline and follow-up HRQL assessments for up to 24 months using the EORTC generic and disease-specific measures, QLQ-C30 and QLQ-OES18. Baseline clinical variables were examined between the treatment groups and changes in mean HRQL scores over time estimated and tested using generalised estimating equations with propensity score (generated by boosted regression) adjustment. Results: Of the 487 patients, 377 underwent TAMK and 110 underwent TTIL. Most clinical variables were similar in the 2 groups; however, there were significantly more patients with AJCC stage 3 disease who underwent TTIL than TAMK (54% vs 32%, P < 0.01) and this was reflected in the survival data. Mean symptom scores for pain were significantly higher in the TTIL group than in TAMK for 2 years postoperatively (P = 0.036). In addition, mean constipation scores were significantly higher for the TTIL group, with a 15-point difference in mean score at 3 months postoperatively (P = 0.037). Conclusions: This large comprehensive nonrandomized analysis of longitudinal HRQL shows that TTIL is associated with more pain and constipation than TAMK