We have investigated the role of iron in intracellular biology Legionella pneumophila human monocytes and effector arm cell-mediated immune defense against this bacterial pathogen. To determine if L. multiplication is dependent, we studied effect chelator deferoxamine on infection monocytes. Deferoxamine at 15 microM completely inhibited multiplication. The inhibitory was reversed with equimolar iron-saturated transferrin but not apotransferrin. examine potential monocyte activation,...

Mycobacterium abscessus is an increasingly important cause of human disease; however, virulence determinants are largely uncharacterized. Previously, it was demonstrated that a rough, wild-type clinical isolate (390R) causes persistent, invasive infection, while smooth isogenic mutant (390S) has lost this capability. During serial passage 390S, spontaneous rough revertant obtained, which named 390V. This regained the ability to infection in monocytes and lungs mice. Glycopeptidolipid (GPL),...

Mycobacterium abscessus causes disease in patients with structural abnormalities of the lung, and it is an emerging pathogen cystic fibrosis. Colonization airways by nontuberculous mycobacteria a harbinger invasive lung disease. facilitated biofilm formation, M. glycopeptidolipids playing important role. can transition between noninvasive, biofilm-forming, smooth colony phenotype that expresses glycopeptidolipid, rough minimal amounts glycopeptidolipid unable to form biofilms. The ability...

ABSTRACT The ability to persist in the host after establishment of infection is an important virulence determinant for mycobacteria. Mycobacterium abscessus a rapidly growing mycobacterial species which causes variety clinical syndromes humans. We have obtained rough, wild-type human isolate M. (M. abscessus-R) and smooth, attenuated mutant abscessus-S ) spontaneously dissociated from isolate. found that abscessus-R able multiply murine pulmonary model contrast , cleared. To understand basis...

We have investigated the regulation of key human iron binding proteins in mononuclear phagocytes by IFN gamma and transferrin. In a previous study, we demonstrated that downregulates expression on monocytes transferrin receptors, major source for cell. present show also intracellular concentration ferritin, storage protein By radioimmunoassay, mean ferritin content nonactivated was 361 +/- 107 fg/monocyte (mean SEM) whereas gamma-activated 64 13 fg/monocyte, an 82% reduction with activation...

ABSTRACT Mycobacterium abscessus causes refractory pulmonary infections requiring surgery for cure. It exists as a smooth biofilm-forming phenotype which is noninvasive and rough, non-biofilm-forming can invade macrophages cause persistent infection in mice. We have postulated that the dissociation of to rough may lead invasive lung disease following initial colonization airways. Amikacin, cefoxitin, clarithromycin are standard therapies this infection. determined MICs these antibiotics...

Chloroquine and ammonium chloride, by virtue of their basic properties, have been shown to raise endocytic lysosomal pH thereby interfere with normal iron metabolism in a variety cell types, including mononuclear phagocytes. Cellular is critical importance Legionella pneumophila, an intracellular bacterial pathogen whose capacity multiply human phagocytes dependent upon the availability iron. In view this, we studied effects chloroquine chloride on L. pneumophila multiplication monocytes....

Two-component systems are important constituents of bacterial regulatory networks. Results this investigation into the role MprAB two-component system Mycobacterium tuberculosis indicate that it is associated with regulation several stress-responsive regulons. Using a deletion mutant lacking portions response regulator, MprA, and histidine kinase, MprB, was demonstrated by real-time PCR, primer extension analyses DNA microarrays activates sigma factor genes sigE sigB, under SDS stress during...

Mycobacterium abscessus is considered to be the most virulent of rapidly growing mycobacteria. Generation bacterial gene knockout mutants has been a useful tool for studying factors that contribute virulence pathogenic bacteria. Until recently, optimal genetic approach generation M. was not clear. Based on recent identification recombineering as preferred approach, mutant generated in which mmpL4b, critical glycopeptidolipid synthesis, deleted. Compared previously well-characterized parental...

We have been exploring the role of iron in pathogenesis intracellular bacterial pathogen Legionella pneumophila. In previous studies, we demonstrated that L. pneumophila multiplication human monocytes is dependent and IFN gamma-activated inhibit by limiting availability iron. this study, investigated effect on lactoferrin, an iron-binding protein which internalized via specific receptors monocytes, nonphysiologic chelates enter a receptor-independent route. Apolactoferrin completely...

Mycobacterium abscessus has emerged as an important cause of lung infection, particularly in patients with bronchiectasis. Innate immune responses must be highly effective at preventing infection M. because it is a ubiquitous environmental saprophyte and normal hosts are not commonly infected. exists either glycopeptidolipid (GPL) expressing variant (smooth phenotype) which GPL masks underlying bioactive cell wall lipids, or lacking immunostimulatory invasive macrophage models. Respiratory...

The rough morphotypes of non-tuberculous mycobacteria have been associated with the most severe illnesses in humans. This idea is consistent fact that Mycobacterium tuberculosis presents a stable morphotype. Unlike smooth morphotypes, bacilli grow close together, leaving no spaces among them and forming large aggregates (clumps). Currently, initial interaction macrophages clumps remains unclear. Thus, we infected J774 bacterial suspensions abscessus containing primarily isolated bacilli....

The human immune response to Mycobacterium tuberculosis is not well characterized. To better understand the cellular tuberculosis, a mononuclear phagocyte culture system using low-infecting inoculum of M. mimic in vivo conditions was developed. Using this system, monocytes treated with IFNgamma/TNFalpha/ calcitriol (CytD) were permissive for growth virulent tuberculosis. In presence iron, however, these suppressed enhanced permissiveness CytD-preincubated found be due TNFalpha, ability iron...

In low-income countries some infections caused by nontuberculous mycobacteria are misdiagnosed as multidrug-resistant tuberculosis. most of these settings the observation microscopic cords is only technique used to identify Mycobacterium tuberculosis in laboratory. this article we definitively demonstrate that abscessus, an emerging pulmonary pathogen, also forms cords.

is a reemerging pathogen that causes pulmonary diseases similar to tuberculosis, which caused by

Mycobacterium abscessus (Mab) is a non-tuberculous mycobacterium that causes pulmonary and non-pulmonary infections. Mab resistant to many chemotherapeutic agents the current treatment options show poor clinical outcomes. Thus, there dire need find new antimicrobials effective at killing Mab. Screening drug libraries identify potential has been impeded by lack of validated HTS assays for In this study, we developed two 384-well high-throughput screening using fluorescent bioluminescent...

Cytometric studies utilizing flow cytometry or multi-well culture plate fluorometry are often limited by a deficit in temporal resolution and lack of single cell consideration. Unfortunately, many cellular processes, including signaling, motility molecular transport, occur transiently over relatively short periods time at different magnitudes between cells. Here we demonstrate the multitrap nanophysiometer (MTNP), low-volume microfluidic platform housing an array traps, as effective tool...

Background Methicillin-resistant Staphylococcus aureus (MRSA) is associated with high mortality rates. Despite antibiotic therapy, persistent bacteremia challenging to treat. Combination therapy ceftaroline has emerged as a potential treatment option; however, the optimal duration and clinical implications after clearance are unknown. Methods This retrospective cohort study examined patients high-grade or MRSA who were treated combination at University of New Mexico Hospital between January...

Growth of Legionella pneumophila within human monocytes is iron dependent. A person with uniquely nonpermissive to L. growth was identified whose expressed an abnormally low number transferrin receptors in the nonactivated state, similar typically level interferon-γ—activated state. The failed up-regulate receptor expression appropriately response iron-transferrin. After treatment for chronic periodontal disease, subject's converted a permissive In contrast had normal and up-regulated Thus,...