Scholars 2009

2009 Future - Global Public Health

Leavitt Azita

Tel Aviv University, Department of Clinical Microbiology and Immunology

"Carbapenem Resistance in Klebsiella Pneumoniae"


January 2017

Azita's Publications:


 November 2010: 

I was honored to receive the Dan David Prize scholarship last year. I have finished my PhD studies in the Department of Clinical Microbiology and Immunology at the Sackler School of Medicine at Tel Aviv University. The research was conducted in the Laboratory of Molecular Epidemiology at Tel Aviv Sourasky Medical Center, affiliated to the School of Medicine. I submitted my thesis combined of six papers in September 2010.

 My research project was focused on a highly antibiotic-resistant strain of the bacterium Klebsiella pneumoniae, which causes a variety of infections among hospitalized patients leading to high morbidity and often adverse outcomes. This specific strain of Klebsiella appeared in Israel four years ago, and in the course of my research, this strain was identified as endemic in our hospital and in other hospitals throughout the country.

 Klebsiella pneumoniae is one of the most important Gram-negative bacterial pathogens, causing pneumonia, urinary tract infections, and sepsis. During the past 25 years, strains of this bacterium, which was originally uniformly susceptible to a wide range of antibiotics, have become multidrug resistant and widespread. In response to this broad-spectrum resistance, carbapenems have been established as the antibiotics of last resort in treating infections caused by Klebsiella, and have been increasingly used in recent decades as the only effective therapy. During the past decade, resistance to carbapenems has developed in this pathogen, leading to strains that are extremely drug resistant and are not responsive to any available antibiotic. These strains of Klebsiella have become a major public health concern. In recent years, the incidence of carbapenem resistance has been increasing, with outbreaks reported in the northeastern United States and other parts of the world. The gene responsible for this resistance is found on a highly transmissible plasmid, which is a DNA molecule that has the ability to transfer between different strains of Klebsiella and can also spread to other pathogens, such as Escherichia coli, Enterobacter and others.

 The main component of my research involved the description of these extensively drug-resistant bacteria in Israel. Through my research, the appearance and spread of these resistant bacteria in Israel were first described.

 My work, using molecular techniques, revealed that the clinical isolates from patients throughout Israel are primarily of the same strain, which is a hyper-epidemic clone of Klebsiella pneumoniae. This strain spread rapidly through Israeli hospitals, infecting approximately 700 patients in 2006 and 1400 patients in 2007. The reported mortality associated with isolation of carbapenem-resistant K. pneumoniae (CRKP) is 44% (~600 deaths).

I have studied the prevalence, the molecular epidemiology, the mechanisms of resistance and the plasmids that encode the resistance among these pathogens. My work has assisted in analyzing the ways resistance is spread and has led to the implementation of measures to prevent transmission in the hospital.

I have also examined the relationship between the Israeli strain of CRKP and strains responsible for various outbreaks in the United States, and shown that the Israeli epidemic clone was likely imported from the United States.

 The results of my work lead to a more in-depth understanding of K. pneumoniae successful spread. My research helped to improve clinical decision-making regarding the choice of antibiotics to treat K. pneumoniae infections, and have helped as well in the design and implementation of infection control measures and national public health efforts in Israel to prevent the further spread of epidemic strains of resistant bacteria.

 The results of the study were published in six papers in leading journals in the field of microbiology and antibiotics and have been presented at national and international conferences. The Dan David Prize scholarship has assisted me to advance my research and helped to making my academic studies more productive. I am glad to inform you that last month I was accepted as an experimental specialist at Weismann Institute of Science and will start working on December 1st.

Thank you for honoring me with this award. Your support is greatly appreciated.