Identification and characterization of the type II secretion system in carbapenemase-producing Klebsiella pneumoniae ST258

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My research program is aimed at understanding how bacteria interact with and shape their local environment. Classic Klebsiella pneumoniae strains form part of our normal flora, but can cause life-threatening infections when our immune system is weakened. These infections are becoming more difficult to treat in Canada and abroad because K. pneumoniae have acquired genes that make them resistant to most, and occasionally, all antibiotics. In the context of the ongoing Covid-19 pandemic, use of antibiotics to treat patients combined with increased hospitalisation rates will increase the risk of hospital-acquired infections and spread of multi-drug resistant (MDR) bacteria like K. pneumoniae. The global spread of specific contemporary MDR K. pneumoniae strains, suggests that in addition to drug resistance they have features that contribute to their success. Identifying and characterizing these features has broad implications for how we approach microbiological control and treatment of MDR K. pneumoniae. Studying the biology of these contemporary K. pneumoniae strains is technically challenging because commonly available molecular biology tools that rely on antibiotics cannot be used or are limited due to antimicrobial resistance. The long-term goal of my research program is to characterise mechanisms used by contemporary K. pneumoniae strains to interact with and shape their local environment. Type II secretion systems are used by many Gram-negative bacteria to transport folded proteins in their active form into the environment. These transported proteins allow bacteria to interact with their surrounding environment to promote bacterial pathogenesis and/or environmental survival. The genes encoding the type II secretion system are widespread among Klebsiella. Yet, no comprehensive studies have been performed in K. pneumoniae and the only known transported protein is a starch debranching enzyme used for nutrient acquisition called pullulanase. We hypothesize that the type II secretion system from K. pneumoniae transports more than one protein and that these proteins allow K. pneumoniae to shape its local environment. My short-term objectives are to develop the tools needed to define how K. pneumoniae uses its type II secretion system to interact with its local environment. Specifically, we will apply molecular genetics techniques and functional assays to (1) generate a contemporary model strain of K. pneumoniae compatible with existing molecular biology tools. (2) Define the individual contribution of each component of the K. pneumoniae type II secretion machinery to protein secretion and (3) identify novel secreted proteins. We will generate a model strain that will simplify the study of MDR K. pneumoniae and perform the first systemic analysis of its type II secretion system. Altogether this work will provide insight into how MDR K. pneumoniae interacts with its local environment, which has broad implications for its microbiological control.