A Chinese research team has identified a specific gene that creates bacteria that cannot be killed by the strongest antibiotics. Medline Plus, the publishing unit for the National Institute of Health (NIH) released an article on Nov. 20, 2015 titled “Gene That Makes Bacteria Resistant to ‘Last Resort’ Antibiotics Found in China.” The MCR-1 gene can resist the strongest available antibiotic. The gene was identified by a team from the South China Agricultural University that was led by Yi-Yun Liu.
The emergence of MCR-1 heralds the breach of the last group of antibiotics, polymyxins, by plasmid-mediated resistance. Our findings emphasize the urgent need for coordinated global action in the fight against pan-drug-resistant Gram-negative bacteria.
Studies were done on meat samples and human patients from 2011 to 2014. The focus was on the MCR-1 gene in an Escherichia coli (E-coli) strain SHP45 and Klebsiella pneumoniae strain from five Chinese provinces. The commonly used murine thigh model confirmed the ability of the MCR-1 gene to provide resistance to polymyxin in living tissue.
The list of antimicrobial classes that were tested in 1999 comes from Science Direct. The Handbook of Animal Models of Infection uses the murine thigh model technique to evaluate the antimicrobial alternatives listed below. Polymyxin was not available at the time. None of these drugs work against the MCR-1 gene.
All antimicrobial classes currently used have been evaluated in the neutropenic murine thigh infection model, including penicillins, cephalosporins, carbapenems, glycopeptides, aminoglycosides, fluoroquinolones, macrolides, tetracyclines, lincosamines, rifamycins and streptogramins.
These findings sound an alarm against the overuse of antibiotics in humans and in feed animals. The prevalence of antibiotic residues in farm runoff, municipal water supplies, and in processed meats are a secondary path to the development of antibiotic resistance. The identification of the MCR-1 gene now makes mutation of bacteria due to overuse of antibiotics a major issue.
Senator Sherrod Brown (D-OH) is on the Agriculture, Nutrition and Forestry committee. Part of his responsibilities includes research into procedures for the delivery of safe foods. You can contact Senator Brown by e-mail to express concerns about overuse of antibiotics in meat foods. You can also express concerns for GMO labeling due to the known cancer producing residues on GMO crops. Senator Brown sponsored a bill to improve the safety procedures of Veterans Affairs hospitals in preventing the spread of MRSA and similar diseases that require the strongest antibiotics.
Development of new antibiotics is a constant endeavor, but the limiting factors are the adverse side effects that these drugs have on the body’s naturally occurring immune system. If more and more bacteria mutate with the MCR-1 gene, we may lose the ability to prevent global pandemics. Food production operations need to minimize antibiotic use. Doctors need to restrict prescriptions of antibiotics to minimize resistance at the individual patient level. Patients need to take antibiotics according to the directions necessary to completely overwhelm the bacterial infection. All of these steps are needed to reduce the rate of mutation of antibiotic resistant bacteria.