Metabolic networks in biological systems are interconnected, such that malfunctioning parts can be corrected by other parts within the network, a process termed adaptive metabolism. Unlike Bacillus Calmette-Guérin (BCG), Mycobacterium tuberculosis (Mtb) better manages its intracellular lifestyle by executing adaptive metabolism. Here, we used metabolomics and identified glutamate synthase (GltB/D) that converts glutamine to glutamate (Q → E) as a metabolic effort used to neutralize cytoplasmic pH that is acidified while consuming host propionate carbon through the methylcitrate cycle (MCC). Methylisocitrate lyase, the last step of the MCC, is intrinsically downregulated in BCG, leading to obstruction of carbon flux toward central carbon metabolism, accumulation of MCC intermediates, and interference with GltB/D mediated neutralizing activity against propionate toxicity. Indeed, vitamin B12 mediated bypass MCC and additional supplement of glutamate led to selectively correct the phenotypic attenuation in BCG and restore the adaptive capacity of BCG to the similar level of Mtb phenotype. Collectively, a defective crosstalk between MCC and Q → E contributes to attenuation of intracellular BCG. Furthermore, GltB/D inhibition enhances the level of propionate toxicity in Mtb. Thus, these findings revealed a new adaptive metabolism and propose GltB/D as a synergistic target to improve the antimicrobial outcomes of MCC inhibition in Mtb.

Salmonella species are among the major pathogens that cause foodborne illness outbreaks. In this study, we aimed to develop a loop-mediated isothermal amplification (LAMP) assay for the rapid and sensitive detection of Salmonella species. We designed LAMP primers targeting the hilA gene as a universal marker of Salmonella species. A total of seven Salmonella species strains and 11 non-Salmonella pathogen strains from eight different genera were used in this study. All Salmonella strains showed positive amplification signals with the Salmonella LAMP assay; however, there was no non-specific amplification signal for the non-Salmonella strains. The detection limit was 100 femtograms (20 copies per reaction), which was ~1,000 times more sensitive than the detection limits of the conventional polymerase chain reaction (PCR) assay (100 pg). The reaction time for a positive amplification signal was less than 20 minutes, which was less than one-third the time taken while using conventional PCR. In conclusion, our Salmonella LAMP assay accurately detected Salmonella species with a higher degree of sensitivity and greater rapidity than the conventional PCR assay, and it may be suitable for point-of-care testing in the field.

Mycobacterium (M.) bovis, a bacterium in the M. tuberculosis complex, is a causative agent of bovine tuberculosis, a contagious disease of animals. Mycobacterial culture is the gold standard for diagnosing bovine tuberculosis, but this technique is laborious and time-consuming. In the present study, performance of the SD Bioline TB Ag MPT4 Rapid test, an immunochromatographic assay, was evaluated using reference bacterial strains and M. bovis field isolates collected from animals. The SD MPT64 Rapid test produced positive results for 95.5% (63/66) of the M. bovis isolates from cattle and 97.9% (46/47) of the isolates from deer. Additionally, the test had a sensitivity of 96.5% (95% CI, 91.2-99.0), specificity of 100% (95% CI, 96.7-100.0), positive predictive value of 100% (95% CI, 96.7-100.0), and negative predictive value of 92.9% (95% CI, 82.7-98.0) for M. bovis isolates. In conclusion, the SD MPT64 Rapid test is simple to use and may be useful for quickly confirming the presence of M. bovis in animals.

Many chemical disinfectants are using to protect the foot and mouth disease (FMD) and avian influenza (AI) in Korea since 2000. This study was performed to confirm disinfective ability of commercialized chemical disinfectants and to investigate the sterilizing ability of E-ball as alterative to chemical disinfectants. 4 kinds of acidulant, 3 kinds of aldehyde, 1 kind of oxidizer and 300 g of E-ball were used in this study. Dilution rate of disinfective power of all chemical disinfectants were to 200 times. The sterilizing ability of aldehydes were better than the acidulant and oxidizer with Salmonella typhimurium. The sterilizing ability of E-ball treated solution was guessed due to the friction of E-ball deads. In the case of the friction of 2 beads of E-ball, Salmonella typhimurium was sterilizted on 1×10 6 /mL CFU in the E-ball treated solution. The E-ball treated solution had superior sterizing power compared with the chemical disinfectants in the bacteria of soil for antibacterial examination. E-ball treated solution has a possibility as the substitute of chemical disinfectants to protective the animal diseases contains FMD, AI.

The aim of the present study was to evaluate the use of an immunochromatographic test (ICT) strip using recombinant MPB70 (rMPB70) protein as a complementary tool for the diagnosis of naturally occurring tuberculosis in cattle. The study was performed on 249 cattle from populations known to be free from Mycobacterium bovis (M. bovis) and 119 cattle with M. bovis infection, confirmed postmortem. Compared to reference standards (culture isolation and/or visible lesion), the sensitivity of ICT was 94.12% (95% CI: 89.89∼98.35%) while the specificity was 96.80% (95% CI; 94.62∼96.82%). The findings indicate that the ICT strip is efficient for diagnosing bovine tuberculosis in cattle from Korea.