What is your objective?

In Asian and African countries, diseases caused by bacteria such as tuberculosis, anthrax, leptospirosis, and salmonellosis are still major concerns. Many of these diseases are so-called zoonses, which can be transmitted between humans and animals. In our laboratory, we have focused on tuberculosis, salmonellosis and leptospirosis, and are studying to understand how these diseases transmit between humans and animals. Based on the data obtained, we aim to design countermeasures to cut off the transmission routes. By offering them to the governments of the affected countries, we would like to contribute to overcoming these diseases. We are also studying Mycobacterium tuberculosis complex, Salmonella enterica, Campylobacter jejuni and coli, as well as Escherichia coli to understand the acquisition mechanism of drug resistance. By utilizing the data from our research, we hope to develop gene diagnostic methods that can quickly detect zoonotic diseases, as well as develop methods to quickly identify medicines for appropriate treatment.

 

What are you doing?

Figure 1  Mycobacterium bovis transmission path in Zambia

We are isolating various bacteria from wild animals like elephants, monkeys, and deer. In addition, we are analyzing the genes of domestic animals like pigs, cows, and chickens, as well as humans in Asian and African countries, and studying the zoonotic potentials. In our research, so far, we have found that Mycobacterium bovis has spread between wild and domestic animals, and that humans can be infected by the pathogen as well. In Nepal, we discovered that elephants have been suffering from tuberculosis by M. tuberculosis from humans.

Figure 2  Gathering pig feces to isolate drug resistant bacteria (Thailand)


Figure 3  A genetic diagnosis kit that can diagnose tuberculosis for 100 yen

Drug resistant bacteria have been reported worldwide and are a major concern. In drug resistant bacteria, alterations at the drug-binding region have been identified. Additionally, an increase in the production of enzymes that inactivate antimicrobials was reported. Furthermore, the ability to export small molecules was shown to increase. These phenotypes are given through mutation and genes transfer between bacteria strains. In our laboratory, we are isolating drug resistant bacteria from domestic animals and humans from Asian and African countries, and are analyzing the characteristics of their genes to understand how they acquired drug resistances. In our study, we identified several amino acid substitutions involving in the resistance to quinolone, one of the most commonly used antibiotics for bacterial infection, by in vitro study using recombinant protein expression and purification techniques. We also have identified the relationship between mobile genetic elements, so called integrins, and the spread of drug resistant bacteria among shrimp and pigs. 

Diagnosing zoonoses and elucidating the drug susceptibility enable effective treatment, and can serve to prevent their spread. Based on the genetic information from bacterial strains collected in Asian and African countries, my department is developing cheap genetic diagnosis methods, fast drug resistance tests, and convenient genetic identifying methods.

 

What's next?

Figure 4  Genetic diagnosis lecture held in Zambia

In Asian and African countries, tuberculosis and other diseases run rampant, killing many people. Drug resistant bacteria are also an indicator of the spread, and containing them is a pressing issue. However, simply collecting and analyzing bacterial strains will not lead to the overcoming of zoonoses. In our laboratory, we are modifying independently developed genetic diagnosis methods to improve them, and are hoping to transfer these methods to Asian and African countries that are suffering from bacterial infections so that they can implement these methods for the diagnosis of active cases.

 

References

(1)  Kimura, Tetsu and Kida, Hiroshi "Zoonotic Diseases (jinju kyoutu kansenshou)", Iyaku (Medicine and Drug) Journal Co., Ltd. (2004)

(2)  http://www.youtube.com/watch?v=QY0fDBaSmVs