A novel method of consensus pan-chromosome assembly and large-scale comparative analysis reveal the highly flexible pan-genome of Acinetobacter baumannii.

Background: Infections by pan-drug resistant Acinetobacter baumannii plague military and civilian healthcare systems. Previous A. baumannii pan-genomic studies used modest sample sizes of low diversity and comparisons to a single reference genome, limiting our understanding of gene order and content.

Amount of usage and involvement in explosions not associated with increased contamination of prehospital vehicles with multi-drug-resistant organisms.

Introduction: The role of explosions and patient transport vehicles as sources and vectors of Gram-negative, multidrug-resistant organisms (MDROs) that predominate infections following lengthy evacuations after disasters due to natural hazards and in current war-trauma patients is unknown.

Hypothesis/problem: Damaged or heavily-used vehicles could be sources of the MDROs subsequently linked to nosocomial infections.

Methods: From January through May 2008 in Iraq, inside surfaces of heavily-used, tactical vehicles (Experimental Group) were sampled with sterile, pre-moistened swabs.

Development and validation of a multiplex TaqMan real-time PCR for rapid detection of genes encoding four types of class D carbapenemase in Acinetobacter baumannii.

A multiplex TaqMan real-time PCR to detect carbapenem-hydrolysing class D β-lactamases (bla(OXA-23)-like, bla(OXA-24/40)-like, bla(OXA-51)-like and bla(OXA-58)-like genes) was developed and evaluated for early detection of imipenem (IMP) resistance in clinically significant Acinetobacter baumannii isolates. Well-characterized strains of A. baumannii were used as positive controls and non-Acinetobacter strains were used to assess specificity.

Characteristics of plasmids in multi-drug-resistant Enterobacteriaceae isolated during prospective surveillance of a newly opened hospital in Iraq.

Background: Gram-negative multidrug-resistant (MDR) bacteria are major causes of nosocomial infections, and antibiotic resistance in these organisms is often plasmid mediated. Data are scarce pertaining to molecular mechanisms of antibiotic resistance in resource constrained areas such as Iraq.

Methodology/principal Findings: In this study, all MDR Enterobacteriaceae (n = 38) and randomly selected non-MDR counterparts (n = 41) isolated from patients, healthcare workers and environmental surfaces in a newly opened hospital in Iraq were investigated to characterize plasmids found in these isolates and determine their contribution to antibiotic resistance.

Bacteriophage-resistant mutants in Yersinia pestis: identification of phage receptors and attenuation for mice.

Background: Bacteriophages specific for Yersinia pestis are routinely used for plague diagnostics and could be an alternative to antibiotics in case of drug-resistant plague. A major concern of bacteriophage therapy is the emergence of phage-resistant mutants. The use of phage cocktails can overcome this problem but only if the phages exploit different receptors.

Gram-negative multidrug-resistant organism colonization in a US military healthcare facility in Iraq.

Objective: To investigate potential sources of gram-negative multidrug-resistant organisms (MDROs) in a deployed US military healthcare facility.

Design: Active surveillance.

Methods: Swab sampling of patients, hospital personnel, and environmental surfaces was performed before the opening of a new medical treatment facility in Iraq and then serially for the next 6 months.

Natural history of colonization with gram-negative multidrug-resistant organisms among hospitalized patients.

Objective: To determine the anatomic sites and natural history of colonization with gram-negative multidrug-resistant organisms (MDROs).

Design: Prospective, longitudinal cohort study.

Setting: Walter Reed Army Medical Center, a 236-bed tertiary care center in Washington, DC.

Early indicators of exposure to biological threat agents using host gene profiles in peripheral blood mononuclear cells.

Background: Effective prophylaxis and treatment for infections caused by biological threat agents (BTA) rely upon early diagnosis and rapid initiation of therapy. Most methods for identifying pathogens in body fluids and tissues require that the pathogen proliferate to detectable and dangerous levels, thereby delaying diagnosis and treatment, especially during the prelatent stages when symptoms for most BTA are indistinguishable flu-like signs.

Methods: To detect exposures to the various pathogens more rapidly, especially during these early stages, we evaluated a suite of host responses to biological threat agents using global gene expression profiling on complementary DNA arrays.

Current trends in plague research: from genomics to virulence.

Yersinia pestis is the causative agent of plague, which diverged from Yersinia pseudotuberculosis within the past 20,000 years. Although these two species share a high degree of homology at the DNA level (>90%), they differ radically in their pathogenicity and transmission. In this review, we briefly outline the known virulence factors that differentiate these two species and emphasize genetic studies that have been conducted comparing Y.

The pH 6 antigen is an antiphagocytic factor produced by Yersinia pestis independent of Yersinia outer proteins and capsule antigen.

The pH 6 antigen (pH 6 Ag; PsaA) of Yersinia pestis has been shown to be a virulence factor. In this study, we set out to investigate the possible function of Y. pestis PsaA in a host cell line, RAW264.

Genotyping of a homogeneous group of Yersinia pestis strains isolated in the United States.

Yersinia pestis, the causative agent of deadly plague, is considered a reemerging infectious disease and a significant biological terrorism threat. The present project focused on epidemiological investigation of the genetic variability of well-documented strains of Y. pestis from the United States by pulsed-field gel electrophoresis (PFGE) and restriction fragment length polymorphism (RFLP) analysis with insertion sequences IS100 and IS285 as probes.