Amino Acid Biosynthetic Pathways Are Required for Klebsiella pneumoniae Growth in Immunocompromised Lungs and Are Druggable Targets during Infection

Abstract

The emergence of multidrug-resistant Klebsiella pneumoniae has rendered a large array of infections difficult to treat. In a high-throughput genetic screen of factors required for K. pneumoniae survival in the lung, amino acid biosynthesis genes were critical for infection in both immunosuppressed and wild-type (WT) mice. The limited pool of amino acids in the lung did not change during infection and was insufficient for K. pneumoniae to overcome attenuating mutations in aroA, hisA, leuA, leuB, serA, serB, trpE, and tyrA in WT and immunosuppressed mice. Deletion of aroA, which encodes 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase class I, resulted in the most severe attenuation. Treatment with the EPSP synthase-specific competitive inhibitor glyphosate decreased K. pneumoniae growth in the lungs. K. pneumoniae expressing two previously identified glyphosate-resistant mutations in EPSP synthase had significant colonization defects in lung infection. Selection and characterization of six spontaneously glyphosate-resistant mutants in K. pneumoniae yielded no mutations in aroA. Strikingly, glyphosate treatment of mice lowered the bacterial burden of two of three spontaneous glyphosate-resistant mutants and further lowered the burden of the less-attenuated EPSP synthase catalytic mutant. Of 39 clinical isolate strains, 9 were resistant to glyphosate at levels comparable to those of selected resistant strains, and none appeared to be more highly resistant. These findings demonstrate amino acid biosynthetic pathways essential for K. pneumoniae infection are promising novel therapeutic targets.

Histidine Utilization Is a Critical Determinant of Acinetobacter Pathogenesis

“…Amino acid profiling of the extracellular lung contents revealed that histidine and other amino acids are detectable, and likely bioavailable, to A. baumannii and other bacterial pathogens. The levels of histidine and several amino acids did not significantly change with infection, which is consistent with metabolite analysis performed on BALF following Klebsiella pneumoniae infection (24). However, other amino acids did change with infections status, such as glutamine and glutamate, which are known modulators of macrophage activity (25).…”

Neutrophils require SKAP2 for reactive oxygen species production following C-type lectin and Candida stimulation

“…Yeast cultures were grown overnight in liquid YPD at 30°C with shaking, washed twice in PBS, counted with the hemocytometer, and resuspended in PBS ( Negoro et al., 2020 ; Xu et al., 2018 ). MKP220, a streptomycin-resistant, capsule type K2 derivative of K. pneumoniae ATCC43816 was grown overnight in liquid LB at 37°C with aeration ( Silver et al., 2019 ; Nguyen et al., 2020 ; Paczosa et al., 2020 ). Overnight cultures were used for in vivo infections.…”

The impact and toxicity of glyphosate and glyphosate-based herbicides on health and immunity

“…In vitro, glyphosate inhibited C. neoformans growth and production of melanin, a compound necessary for virulence (Nosanchuk et al 2001). Likewise, in mice, intranasal spraying of glyphosate limited an infection by Klebsiella pneumoniae (commensal bacterium in the intestine, but pathogenic elsewhere) (Silver et al 2019). Though aware of the hazards from the use of glyphosate as a treatment, the authors acknowledged that the agent could be a useful tool to test the therapeutic potentials of drugs that could target aromatic amino acid production.…”