Bacterial Metallophores in the Diagnosis of Acute Pyelonephritis

Acute pyelonephritis (AP) is a clinical syndrome characterized by fever, chills, nausea vomiting and costovertebral angle tenderness, bacteriuria and pyuria. The underlying pathophysiology is based on the presence of microbes in the renal parenchyma which may progress to sepsis. Complicated urinary tract infection (cUTI) is one accompanied by abnormalities of the urinary tract or host factors which make the eradication of the infection difficult. The most common etiological agents include gram-negative enteric rods, i.e. E. coli, Klebsiella pneumoniae; and Enterococcus spp. Empirical antibiotic treatment should be targeted once culture and sensitivity results become available. This usually takes 24-48 hours, occasionally even 72 hours. Inadequate antibiotic treatment leads to higher mortality if the etiological agent is of a multi-drug resistant phenotype. Metallophores are a major virulence factor of bacterial pathogens. These are chelating molecules secreted by the microbe for the uptake of iron, copper, and other metals from the host. E.g., siderophores aim at Fe3+ ions removal from the host protein molecules; the complex then adheres to specific extracellular receptors on the microbial cell and is internalized. Yersiniabactin is another metallophore which binds copper. Proteomic analysis using mass spectrometry has been used in the detection of biomarkers for several pathological conditions: renal failure, post-transplant nephropathy, various malignancies etc. Metallophores can be detected by mass spectrometry.