Ramy Fodah | University of Louisville, KY (original) (raw)
Papers by Ramy Fodah
Saudi Journal of Biological Sciences
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, Jan 28, 2017
2-(18)F-Fluorodeoxysorbitol ((18)F-FDS) has been shown to be a promising agent with high selectiv... more 2-(18)F-Fluorodeoxysorbitol ((18)F-FDS) has been shown to be a promising agent with high selectivity and sensitivity in imaging bacterial infection. The objective of our study was to validate (18)F-FDS as a potential radiopharmaceutical for imaging bacterial infection longitudinally in the lung. Methods: Albino C57 female mice were intratracheally inoculated with either live or dead Klebsiella pneumoniae (Kp) to induce either lung infection or inflammation. One group of mice was imaged to monitor disease progression. PET/CT was performed on day 0, 1, 2, and 3 post infection (PI) using either (18)F-FDS or 2-deoxy-2-((18)F)-fluoro-D-glucose ((18)F-FDG) (n = 12 for each tracer). The other group was screened by bioluminescent imaging (BLI) first to select mice only with visible infection (region of interest (ROI) > 10^8 ph/s) for PET/CT imaging with (18)F-FDS (n = 12). For the inflammation group, five mice each were imaged with PET/CT using either (18)F-FDS or (18)F-FDG from day 1 to...
ABSTRACT Background: Klebsiella pneumoniae (Kp) is a Gram-negative bacterial pathogen which cause... more ABSTRACT Background: Klebsiella pneumoniae (Kp) is a Gram-negative bacterial pathogen which causes disease on a variety of host mucosal surfaces and is increasingly prevalent amongst nosocomial infections in part due to acquisition of numerous antibiotic resistance genes. Kp is considered an extracellular pathogen which uses capsular polysaccharide to resist uptake by professional phagocytes. We demonstrate that Kp is not limited to persistence in extracellular host niches, but is viable within cultured macrophages. Methods: Capsular polysaccharide mutants of ATCC 43816 and NTUH-K2044 strains were used to infect murine macrophage cell lines (J774A.1 and RAW264.7) and compared to the uptake of the avirulent strain MGH 78578. Time course studies evaluated the replication potential of the three wild type strains in macrophages until 12 hr post infection. Virulence of Kp strains was tested in a BALB/c intubation-mediated intratracheal respiratory disease model. Disease progression of bioluminescent Kp lung infections were monitored in mice. Results: Capsule mutants were phagocytosed at higher rates than their isogenic parents, but not as well as the avirulent strain MGH 78578 strain, suggesting that factors additional to capsular polysaccharide mediate the antiphagocytic properties of Kp. All three Kp strains were replication competent within macrophages. All tested Kp strains were of clinical origin, however a significant difference in the LD50s of virulent ATCC 43816 (101.7 CFU) and NTUH-K2044 (101.4 CFU) strains was observed compared to relatively avirulent MGH 78578 (107.1 CFU). Optical imaging characterized multiple sites of infection. Conclusions: The lifestyle of Kp within mammalian hosts may involve unique host niches, and we importantly provide evidence that Kp interaction with phagocytes is not a simple antiphagocytic interaction. Further, modulation of phagocytosis is dependent on more than capsular polysaccharide, and internalized bacteria are replication competent. The translational implications of this work influence the design of diagnostics and therapeutics which should not be strictly targeted to extracellular bacteria. While the majority of Kp bacteria may be extracellular during the course of disease, we propose that a subpopulation may enter cells and provide unique challenges for therapeutic intervention.
Klebsiella pneumoniae is a common causative agent for community and hospital acquired pneumonia. ... more Klebsiella pneumoniae is a common causative agent for community and hospital acquired pneumonia. The acute respiratory disease induced by those microbes progress rapidly leading to multi-lobar involvement and abscess formation which leaves a little time for medical intervention resulting in high mortality rates [1]. Currently, there is no model system available that allows for real-time monitoring of the progression of the pneumonic disease complicating the ability to study disease development in live animals. Using the luxCDABE bio-reporter system and homologous recombination approach, we have engineered a light producing K. pneumoniae strain (JSKP001), examined the capability of the microbes to induce the pulmonary disease in a murine-infection model, and we were able to monitor disease progression in vivo. We employed the bioluminescent JSKP001 strain to visualize bacterial dissemination and characterized the trafficking of K. pneumoniae to multiple organs including the unexpecte...
American journal of physiology. Lung cellular and molecular physiology, Jan 15, 2015
Chlorine is a toxic gas used in a variety of industrial processes and is considered a chemical th... more Chlorine is a toxic gas used in a variety of industrial processes and is considered a chemical threat agent. High-level chlorine exposure causes acute lung injury, but the long-term effects of acute chlorine exposure are unclear. Here we characterized chronic pulmonary changes following acute chlorine exposure in mice. A/J mice were exposed to 240 parts per million-hour chlorine or sham-exposed to air. Chlorine inhalation caused sloughing of bronchial epithelium 1 day after chlorine exposure, which was repaired with restoration of a pseudostratified epithelium by day 7. The repaired epithelium contained an abnormal distribution of epithelial cells containing clusters of club or ciliated cells rather than the uniformly interspersed pattern of these cells in unexposed mice. Although the damaged epithelium in A/J mice was repaired rapidly, and minimal airway fibrosis was observed, chlorine-exposed mice developed pneumonitis characterized by infiltration of alveoli with neutrophils and ...
Journal of Visualized Experiments
Respiratory disease studies typically involve the use of murine models as surrogate systems. Howe... more Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences between the murine and human respiratory systems, especially in their upper respiratory tracts (URT). In some models, these differences in the murine nasal cavity can have a significant impact on disease progression and presentation in the lower respiratory tract (LRT) when using intranasal instillation techniques, potentially limiting the usefulness of the mouse model to study these diseases. For these reasons, it would be advantageous to develop a technique to instill bacteria directly into the mouse lungs in order to study LRT disease in the absence of involvement of the URT. We have termed this lung specific delivery technique intubation-mediated intratracheal (IMIT) instillation. This noninvasive technique minimizes the potential for instillation into the bloodstream, which can occur during more invasive traditional surgical intratr...
Klebsiella pneumoniae is a bacterial pathogen of worldwide importance and a significant contribut... more Klebsiella pneumoniae is a bacterial pathogen of worldwide importance and a significant contributor to multiple disease presentations associated with both nosocomial and community acquired disease. ATCC 43816 is a well-studied K. pneumoniae strain which is capable of causing an acute respiratory disease in surrogate animal models. In this study, we performed sequencing of the ATCC 43816 genome to support future efforts characterizing genetic elements required for disease. Furthermore, we performed comparative genetic analyses to the previously sequenced genomes from NTUH-K2044 and MGH 78578 to gain an understanding of the conservation of known virulence determinants amongst the three strains. We found that ATCC 43816 and NTUH-K2044 both possess the known virulence determinant for yersiniabactin, as well as a Type 4 secretion system (T4SS), CRISPR system, and an acetonin catabolism locus, all absent from MGH 78578. While both NTUH-K2044 and MGH 78578 are clinical isolates, little is known about the disease potential of these strains in cell culture and animal models. Thus, we also performed functional analyses in the murine macrophage cell lines RAW264.7 and J774A.1 and found that MGH 78578 (K52 serotype) was internalized at higher levels than ATCC 43816 (K2) and NTUH-K2044 (K1), consistent with previous characterization of the antiphagocytic properties of K1 and K2 serotype capsules. We also examined the three K. pneumoniae strains in a novel BALB/c respiratory disease model and found that ATCC 43816 and NTUH-K2044 are highly virulent (LD50<100 CFU) while MGH 78578 is relatively avirulent.
Saudi Journal of Biological Sciences
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, Jan 28, 2017
2-(18)F-Fluorodeoxysorbitol ((18)F-FDS) has been shown to be a promising agent with high selectiv... more 2-(18)F-Fluorodeoxysorbitol ((18)F-FDS) has been shown to be a promising agent with high selectivity and sensitivity in imaging bacterial infection. The objective of our study was to validate (18)F-FDS as a potential radiopharmaceutical for imaging bacterial infection longitudinally in the lung. Methods: Albino C57 female mice were intratracheally inoculated with either live or dead Klebsiella pneumoniae (Kp) to induce either lung infection or inflammation. One group of mice was imaged to monitor disease progression. PET/CT was performed on day 0, 1, 2, and 3 post infection (PI) using either (18)F-FDS or 2-deoxy-2-((18)F)-fluoro-D-glucose ((18)F-FDG) (n = 12 for each tracer). The other group was screened by bioluminescent imaging (BLI) first to select mice only with visible infection (region of interest (ROI) > 10^8 ph/s) for PET/CT imaging with (18)F-FDS (n = 12). For the inflammation group, five mice each were imaged with PET/CT using either (18)F-FDS or (18)F-FDG from day 1 to...
ABSTRACT Background: Klebsiella pneumoniae (Kp) is a Gram-negative bacterial pathogen which cause... more ABSTRACT Background: Klebsiella pneumoniae (Kp) is a Gram-negative bacterial pathogen which causes disease on a variety of host mucosal surfaces and is increasingly prevalent amongst nosocomial infections in part due to acquisition of numerous antibiotic resistance genes. Kp is considered an extracellular pathogen which uses capsular polysaccharide to resist uptake by professional phagocytes. We demonstrate that Kp is not limited to persistence in extracellular host niches, but is viable within cultured macrophages. Methods: Capsular polysaccharide mutants of ATCC 43816 and NTUH-K2044 strains were used to infect murine macrophage cell lines (J774A.1 and RAW264.7) and compared to the uptake of the avirulent strain MGH 78578. Time course studies evaluated the replication potential of the three wild type strains in macrophages until 12 hr post infection. Virulence of Kp strains was tested in a BALB/c intubation-mediated intratracheal respiratory disease model. Disease progression of bioluminescent Kp lung infections were monitored in mice. Results: Capsule mutants were phagocytosed at higher rates than their isogenic parents, but not as well as the avirulent strain MGH 78578 strain, suggesting that factors additional to capsular polysaccharide mediate the antiphagocytic properties of Kp. All three Kp strains were replication competent within macrophages. All tested Kp strains were of clinical origin, however a significant difference in the LD50s of virulent ATCC 43816 (101.7 CFU) and NTUH-K2044 (101.4 CFU) strains was observed compared to relatively avirulent MGH 78578 (107.1 CFU). Optical imaging characterized multiple sites of infection. Conclusions: The lifestyle of Kp within mammalian hosts may involve unique host niches, and we importantly provide evidence that Kp interaction with phagocytes is not a simple antiphagocytic interaction. Further, modulation of phagocytosis is dependent on more than capsular polysaccharide, and internalized bacteria are replication competent. The translational implications of this work influence the design of diagnostics and therapeutics which should not be strictly targeted to extracellular bacteria. While the majority of Kp bacteria may be extracellular during the course of disease, we propose that a subpopulation may enter cells and provide unique challenges for therapeutic intervention.
Klebsiella pneumoniae is a common causative agent for community and hospital acquired pneumonia. ... more Klebsiella pneumoniae is a common causative agent for community and hospital acquired pneumonia. The acute respiratory disease induced by those microbes progress rapidly leading to multi-lobar involvement and abscess formation which leaves a little time for medical intervention resulting in high mortality rates [1]. Currently, there is no model system available that allows for real-time monitoring of the progression of the pneumonic disease complicating the ability to study disease development in live animals. Using the luxCDABE bio-reporter system and homologous recombination approach, we have engineered a light producing K. pneumoniae strain (JSKP001), examined the capability of the microbes to induce the pulmonary disease in a murine-infection model, and we were able to monitor disease progression in vivo. We employed the bioluminescent JSKP001 strain to visualize bacterial dissemination and characterized the trafficking of K. pneumoniae to multiple organs including the unexpecte...
American journal of physiology. Lung cellular and molecular physiology, Jan 15, 2015
Chlorine is a toxic gas used in a variety of industrial processes and is considered a chemical th... more Chlorine is a toxic gas used in a variety of industrial processes and is considered a chemical threat agent. High-level chlorine exposure causes acute lung injury, but the long-term effects of acute chlorine exposure are unclear. Here we characterized chronic pulmonary changes following acute chlorine exposure in mice. A/J mice were exposed to 240 parts per million-hour chlorine or sham-exposed to air. Chlorine inhalation caused sloughing of bronchial epithelium 1 day after chlorine exposure, which was repaired with restoration of a pseudostratified epithelium by day 7. The repaired epithelium contained an abnormal distribution of epithelial cells containing clusters of club or ciliated cells rather than the uniformly interspersed pattern of these cells in unexposed mice. Although the damaged epithelium in A/J mice was repaired rapidly, and minimal airway fibrosis was observed, chlorine-exposed mice developed pneumonitis characterized by infiltration of alveoli with neutrophils and ...
Journal of Visualized Experiments
Respiratory disease studies typically involve the use of murine models as surrogate systems. Howe... more Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences between the murine and human respiratory systems, especially in their upper respiratory tracts (URT). In some models, these differences in the murine nasal cavity can have a significant impact on disease progression and presentation in the lower respiratory tract (LRT) when using intranasal instillation techniques, potentially limiting the usefulness of the mouse model to study these diseases. For these reasons, it would be advantageous to develop a technique to instill bacteria directly into the mouse lungs in order to study LRT disease in the absence of involvement of the URT. We have termed this lung specific delivery technique intubation-mediated intratracheal (IMIT) instillation. This noninvasive technique minimizes the potential for instillation into the bloodstream, which can occur during more invasive traditional surgical intratr...
Klebsiella pneumoniae is a bacterial pathogen of worldwide importance and a significant contribut... more Klebsiella pneumoniae is a bacterial pathogen of worldwide importance and a significant contributor to multiple disease presentations associated with both nosocomial and community acquired disease. ATCC 43816 is a well-studied K. pneumoniae strain which is capable of causing an acute respiratory disease in surrogate animal models. In this study, we performed sequencing of the ATCC 43816 genome to support future efforts characterizing genetic elements required for disease. Furthermore, we performed comparative genetic analyses to the previously sequenced genomes from NTUH-K2044 and MGH 78578 to gain an understanding of the conservation of known virulence determinants amongst the three strains. We found that ATCC 43816 and NTUH-K2044 both possess the known virulence determinant for yersiniabactin, as well as a Type 4 secretion system (T4SS), CRISPR system, and an acetonin catabolism locus, all absent from MGH 78578. While both NTUH-K2044 and MGH 78578 are clinical isolates, little is known about the disease potential of these strains in cell culture and animal models. Thus, we also performed functional analyses in the murine macrophage cell lines RAW264.7 and J774A.1 and found that MGH 78578 (K52 serotype) was internalized at higher levels than ATCC 43816 (K2) and NTUH-K2044 (K1), consistent with previous characterization of the antiphagocytic properties of K1 and K2 serotype capsules. We also examined the three K. pneumoniae strains in a novel BALB/c respiratory disease model and found that ATCC 43816 and NTUH-K2044 are highly virulent (LD50<100 CFU) while MGH 78578 is relatively avirulent.