Cystatins 9 and C as a Novel Immunotherapy Treatment That Protects against Multidrug-Resistant New Delhi Metallo-Beta-Lactamase-1-Producing Klebsiella pneumoniae.

Alex J Holloway,Jiehjuen Yu,Bernard P Arulanandam,Tonyia Eaves-Pyles,Sarah M Hoskinson

doi:10.1128/aac.01900-17

Abstract

ABSTRACTMultidrug-resistant (MDR) bacterial pneumonia can induce dysregulated pulmonary and systemic inflammation leading to morbidity and mortality. Antibiotics to treat MDR pathogens do not function to modulate the extent and intensity of inflammation and can have serious side effects. Here we evaluate the efficacy of two human cysteine proteinase inhibitors, cystatin 9 (CST9) and cystatin C (CSTC), as a novel immunotherapeutic treatment to combat MDR New Delhi metallo-beta-lactamase-1 (NDM-1)-producing Klebsiella pneumoniae. Our results showed that mice infected intranasally (i.n.) with a 90% lethal dose (LD90) challenge of NDM-1 K. pneumoniae and then treated with the combination of human recombinant CST9 (rCST9) and rCSTC (rCSTs; 50 pg of each i.n. at 1 h postinfection [p.i.] and/or 500 pg of each intraperitoneally [i.p.] at 3 days p.i.) had significantly improved survival compared to that of infected mice alone or infected mice treated with individual rCSTs (P < 0.05). Results showed that both of our optimal rCST treatment regimens modulated pulmonary and systemic proinflammatory cytokine secretion in the serum, lungs, liver, and spleen in infected mice (P < 0.05). Treatment also significantly decreased the bacterial burden (P < 0.05) while preserving lung integrity, with reduced inflammatory cell accumulation compared to that in infected mice. Further, rCST treatment regimens reduced lipid peroxidation and cell apoptosis in the lungs of infected mice. Additionally, in vitro studies showed that rCSTs (50 or 500 pg of each) directly decreased the viability of NDM-1 K. pneumoniae. In conclusion, the data showed that rCST9/rCSTC worked synergistically to modulate host inflammation against MDR NDM-1 K. pneumoniae pneumonia, which significantly improved survival. Therefore, rCST9/rCSTC is a promising therapeutic candidate for the treatment of bacterial pneumonia.

Highlights

Multidrug-resistant (MDR) bacterial pneumonia can induce dysregulated pulmonary and systemic inflammation leading to morbidity and mortality
The results showed that i.n. monotherapy treatment with either recombinant CST9 (rCST9) or rCSTC at 50 or 500 pg delivered at 1 day and/or 3 days p.i. increased survival 5 to 20% compared to the findings with untreated New Delhi metallo-beta-lactamase-1 (NDM-1) K. pneumoniae-infected mice
The ability of bacterial organisms to acquire MDR genes is on the rise, making infections caused by MDR pathogens difficult to treat with traditional antibiotics

Summary

Introduction

Multidrug-resistant (MDR) bacterial pneumonia can induce dysregulated pulmonary and systemic inflammation leading to morbidity and mortality. Our results showed that mice infected intranasally (i.n.) with a 90% lethal dose (LD90) challenge of NDM-1 K. pneumoniae and treated with the combination of human recombinant CST9 (rCST9) and rCSTC (rCSTs; 50 pg of each i.n. at 1 h postinfection [p.i.] and/or 500 pg of each intraperitoneally [i.p.] at 3 days p.i.) had significantly improved survival compared to that of infected mice alone or infected mice treated with individual rCSTs (P Ͻ 0.05) Results showed that both of our optimal rCST treatment regimens modulated pulmonary and systemic proinflammatory cytokine secretion in the serum, lungs, liver, and spleen in infected mice (P Ͻ 0.05). The NDM-1producing bacteria can cause life-threatening lung injury, characterized by dysregulated inflammatory responses leading to (i) excess cytokine secretion; (ii) increased tissue breakdown by MMPs (proteinase-proteinase inhibitor imbalance), with subsequent destruction of the alveolar epithelium and vascular endothelium [30, 31]; and (iii) increased permeability of the alveolar wall and accumulation of inflammatory cells [30,31,32]

Methods

Results

Conclusion