Antibiotic resistance and emergence of superbugs: a rising threat to public health

Monday, March 19, 2012 - 3:00pm
Event Type: 

1420 Molecular Biology Bldg.

Qijing Zhang, Professor, Frank Ramsey Endowed Chair, Department of Veterinary Microbiology and Preventive Medicine, ISU

ABSTRACT: Antibiotics have been the most effective therapeutic agents against infectious diseases caused by bacterial pathogens. However, antibiotic-resistant pathogens are increasingly prevalent, posing a serious threat to global public health. Acquisition of antibiotic resistance not only compromises the usefulness of clinically important antibiotics, but also affects the evolution and pathogenicity of bacterial pathogens, results in the emergence and spread of ‘superbugs’ that are hypervirulent and resistant to multiple drugs. Campylobacter is a major zoonotic pathogen and has developed resistance to various antibiotics that are used for animal production and human medicine. Recently a hypervirulent Campylobacter clone has emerged in ruminants and has become the predominant cause of sheep abortion in the U.S. Zoonotic transmission of this hypervirulent clone to humans has occurred, resulting in a number of cases of foodborne illnesses in recent years. Notably, all isolates of this emergent clone are resistant to tetracycline, the only class of antibiotics approved for the treatment of sheep abortion in the U.S., suggesting that use of tetracycline has facilitated the evolution of this pathogenic clone. Additionally, Campylobacter has developed resistance to fluoroquinolones and macrolides, the drugs of choice for treating campylobacteriosis in humans. Acquisition of fluoroquinolone resistance enhances the fitness of Campylobacter in its natural hosts, leading to persistence of fluoroquinolone-resistant Campylobacter in the absence of antibiotic selection pressure. This fitness-enhancing effect creates a significant challenge for the control of fluoroquinolone resistance in Campylobacter. To combat antibiotic resistance and limit the spread of superbugs, enhanced efforts are needed to understand the ecology and transmission dynamics of antibiotic resistance, discover new or alternative antimicrobials, and develop novel treatment schemes that avoid the selection of antibiotic-resistant variants.