RESUMO
BACKGROUND: The discovery of novel therapeutic agents, especially those targeting mycobacterial membrane protein large 3 (mmpL3), has shown promise. In this study, the CRISPR interference-Streptococcus thermophilus nuclease-deactivated Cas9 (CRISPRi-dCas9Sth1) system was utilized to suppress mmpL3 expression in Mycobacterium smegmatis, and its impacts on susceptibility to antimicrobial agents were evaluated. METHODS: The repression of the mmpL3 gene was confirmed by RT-qPCR. The essentiality, growth curve, viability, and antimicrobial susceptibility of the mmpL3 knockdown strain were investigated. RESULTS: mmpL3 silencing was achieved by utilizing 0.5 and 1 ng/mL anhydrotetracycline (ATc), resulting in reductions in the expression of 60.4% and 74.4%, respectively. mmpL3 silencing led to a significant decrease in bacterial viability when combined with one-half of the minimal inhibitory concentrations (MICs) of rifampicin, rifabutin, ceftriaxone, or isoniazid, along with 0.1 or 0.5 ng/mL ATc (p < 0.05). However, no significant difference was observed for clarithromycin or amikacin. CONCLUSIONS: The downregulation of the mmpL3 gene in mycobacteria was achieved through the use of CRISPRi-dCas9Sth1, resulting in growth deficiencies and resensitization to certain antimicrobial agents. The impact was dependent upon the level of gene expression.
RESUMO
BACKGROUND: COVID-19 infection is caused by a novel coronavirus. One of the most used strategies that can be used to control the spread of COVID-19 is the 3T (test, trace, and treatment) strategy. This study aimed to evaluate the 3T strategy to control COVID-19 infection in a COVID-19 Referral Hospital in Depok, West Java, Indonesia. METHODS: this is a cross-sectional study conducted at the University of Indonesia Hospital. The study was conducted in June 2020 with 742 participants (staff members) using secondary data from polymerase chain reaction (PCR) test results. We presented data in the descriptive form and performed bivariate analysis using the chi-square/Fischer test for categorical data. RESULTS: the PCR test results were positive in 83 (11.1%) participants, with a case-per-tracing ratio of 1:24 and 1:2 in the first and third phases of tracing, respectively. The COVID-19 case graph for the participants decreased along with the implementation of the 3T strategy. The positivity rate in the first phase of tracing was 20% and decreased to 5% in the third phase of tracing. Staff with confirmed positive test results were advised to isolate themselves (hospital or self-isolation). Hospital isolation was found to be associated with the duration of PCR test conversion (p<0.001). CONCLUSION: the 3T strategy is effective for controlling the spread of COVID-19. The strategy should be implemented simultaneously with other health precautions to reduce the risk of spreading infection.
