Ferroptosis is a new type of cell death marked by iron and lipid ROS accumulation. GPX4 is one of the glutathione peroxidases known to regulate ferroptosis tightly. On the other hand, Nrf2 also plays a vital role in ferroptosis as it targets genes related to oxidant defense. Herein, we employed beas-2 human epithelial cells treated with a low concentration of RSL3 to induce ferroptosis. To study the protective role of Nrf2, we used ML385 as its specific inhibitor. A combination of ML385 and a low concentration of RSL3 synergistically induced more toxicity to RSL3. Furthermore, we found that mitochondrial ROS is elevated in ML385 and RSL3 combination group. In addition, Mito TEMPOL application successfully prevents the upregulation of mitochondrial ROS, lipid ROS, reduces the toxicity of RSL3, restores the antioxidant capacity of the cells, and mitochondrial functions reflected by mitochondrial membrane potential and mitochondrial oxidative phosphorylation system (OXPHOS) expression. Altogether, our study demonstrated that Nrf2 inhibition by ML385 induces more toxicity when combined with RSL3 through the elevation of mitochondrial ROS and disruption of mitochondrial function.

Primaquine is an effective anti-hypnozoite drug for Plasmodium vivax and Plasmodium ovale. However, it can trigger erythrocyte hemolysis in people with glucose 6-phosphate dehydrogenase (G6PD) deficiency. In a previous report from South Central Timor (SCT), Indonesia, we described the prevalence of Vanua Lava, Chatham, and Viangchan variants; in this study, other G6PD variants (Kaiping, Coimbra, Gaohe, Canton, and Mahidol) were subsequently analyzed. For clarity, all of these results are described together. The 381 DNA samples from the previous study during 2013–2014 were analyzed for G6PD variants by using PCR-RFLP. The prevalence of G6PD deficiency in SCT was 6.3% (24/381 cases), including 4.2% (16/381 cases), 0.5% (2/381 cases), and 1.6% (6/381 cases) for Coimbra, Kaiping, and Vanua Lava variants, respectively. No other variants were found in this population. A significant association was found between ethnicity and the distribution of G6PD Kaiping in female subjects. A positive association was shown between G6PD activity and heterozygous females carrying Coimbra genotype, hemizygous males carrying Vanua Lava, Plasmodium falciparum infection in female subjects, and P. vivax infection in male subjects. Further molecular analysis of heterozygous females, particularly in malaria-endemic areas, is needed for mapping distribution of G6PD deficiency status in Indonesia.

BACKGROUND: Diptheria cases are treated with both anti-diphtheria serum (ADS) and antibiotics. Penicillin and erythromycin are the primary choices for any Corynebacterium diphtheriae (C. diphtheriae) infection. Antibiotic susceptibility pattern of C. diphtheriae has not been reported in Indonesia since 1982. The improper use of antibiotics, as well as, the consumption of antibiotics without prescription, will increase the resistance of C. diphtheriae. This study aims to determine the susceptibility pattern and the effectiveness of C. diphtheriae to several antibiotics. METHODS: A total of 57 C. diphtheriae isolates were recultured by using Blood Agar (BA) and Cystine Tellurite Blood Agar (CTBA). Afterward, these isolates were identified by using API Coryne. The antibiotic susceptibility pattern was determined by using Kirby Bauer Method based on CLSI M45-A2. RESULTS: These studies revealed that as the primary choice of diphtheria cases, 10.5% of C. diphtheriae isolates were resistant to Penicillin and 5.3% were resistant to erythromycin. Seven isolates (12%) showed resistance to more than one antibiotics, such as tetracycline and clindamycin, vancomycin and clindamycin, penicillin and tetracycline, also penicillin and vancomycin. Moreover, 4 isolates (7%) were resistant to 3-5 antibiotics. All isolates were susceptible to moxifloxacin and linezolid. CONCLUSION: Some C. diphtheriae isolates were resistant to penicillin and erythromycin, which are known as the primary choice for the treatment of C. diphtheriae infection. Even though, all isolates susceptible to moxifloxacin and linezolid. KEYWORDS: Corynebacterium diphtheriae, resistance, antimicrobial

Pertussis cases have been reported most frequently in developed countries, but they are predicted to be the most prevalent in developing countries. Indonesia, a developing country, routinely conducts case-based surveillance for pertussis. We reviewed the data on pertussis cases and close contacts based on clinical sample documents examined in the National Reference Laboratory for pertussis, Indonesia (2016–2020). Our objective was to analyze the laboratory and epidemiological aspects of pertussis cases and close contacts, particularly to evaluate the implementation of a 5-year case-based surveillance of pertussis in Indonesia. Data were collected from sample documents and annual laboratory reports between January 2016 and December 2020. We analyzed the proportion of pertussis cases and close contacts by geographic region, year, age, and sex. We used the χ² test to correlate the laboratory and epidemiological data. In total, 274 clinical cases of pertussis and 491 close contacts were recorded in 15 provinces. The peak number of cases occurred in 2019, with a positivity rate (percentage of laboratory-confirmed cases) of 41.23% (47/114). Clinical cases were dominated by infants aged <1 year (55.5%), and 52.9% of them were aged <6 months. Similarly, 72.3% (68/94) of the laboratory-confirmed cases were infants. Both clinical cases and positivity rates tended to be higher in females (155 cases, 38.1%) than in males (119 cases, 29.4%). No confirmed cases were found in children aged ≥10 years, although positive results still occurred in close contact. Age-group and laboratory-confirmed cases were correlated (p = 0.00). Clinical and confirmed cases of pertussis occurred mostly in the early age group and may be lower in those aged ≥10 years, especially in confirmed cases. New policies are needed for pertussis prevention at an early age, as well as the application of serology tests to increase laboratory-confirmed cases in children aged ≥10 years.

Background/aim: The aim of this study was to find out characteristics and patterns of the spread of Corynebacterium diphtheriae isolated from Jakarta and the surrounding areas, using the whole genome sequencing (WGS) technique and multilocus sequence typing (MLST) approach. Materials and methods: The study samples consisted of 86 C. diphtheriae isolates, which were isolated from diphtheria patients and close contacts of patients. The DNA sequencing was carried out using the WGS technique. Data conversion applied the U-gene software. Molecular typing was conducted through the MLST approach, then followed by online data analysis. Results: The results showed that as many as 43 (50%) of all samples examined were new types with the same allele profile, namely 9-1-13-4-3-3-4. New sequence type C. diphtheriae is registered in the MLST global database as ST534 based on the allele profile. The tox gene analysis in 43 isolates with ST534 indicated that there were three mutation positions, all of which were silent mutations. Conclusion: The main cause of diphtheria in Jakarta and the surrounding areas is a new sequence type of C. diphtheriae registered as ST534.

BACKGROUND: dtxR gene is a global regulator that can be used as a marker for detection of Corynebacterium diphtheriae (C. diphtheriae) and it is also a representative tool for mapping purpose (molecular typing) of this bacteria. The aim of this study was to analyze the DNA sequences of partial dtxR gene of C. diphtheriae causing diphtheria in some region of Indonesia. DNA sequence analysis was used to verify the accuracy of the in-house multiplex polymerase chain reaction (PCR) method that used for detection of C. diphtheriae in the clinical specimen as well as a preliminary study to determine the strain diversity of C. diphtheriae circulating in Indonesia.METHODS:Ten PCR products targeting the dtxR gene that have been detected as positive C. diphtheriae previously by in-house multiplex PCR used as samples in this study. The DNA sequencing carried out by Sanger method and the sequence data was analyzed by Bioedit software offline and basic local alignment sequence typing (BLAST) online.RESULTS: All of DNA sequence analyzed in this study were similar or identical to the dtxR gene sequence data of C. diphtheriae registered in GenBank. Within the 162 nucleotides (base 150-311) of dtxR gene that analyzed, at least 2 clonals were found among 10 samples. Substitutions of 2 nucleotides (base 225 and 273) was detected, both were silent mutation.CONCLUSION:Ten partial DNA sequences of dtxR genes in this study verify the accuracy of in-house multiplex PCR which used to identify the bacteria causing diphtheria in the clinical specimen. The DNA sequences also represent the existing diversity of the bacteria causing diphtheria circulating in Indonesia.KEYWORDS: dtxR, C. diphtheriae, diphtheria, Indonesia