Field efficacy and non‐target effects of temephos granules against Culex pipiens (Diptera: Culicidae) and microorganisms in septic tanks,Republic of Korea

A granular formulation of 1.0% temephos (temephos G) was tested for its efficacy in mosquito larval control, residual effects and effects on non‐target microorganisms. Culex pipiens complex in septic tanks in Yangsan, Republic of Korea were used for this study. Microorganisms in the same septic tanks were used for study of non‐target organisms. After the application of temephos G at the rates of 2.0 and 5.0 mg/L to selected septic tanks, mortalities were recorded for 50 days. The effect of temephos G on non‐target organisms was studied by evaluating its effects on the bacterial populations in the treated septic tanks. It was observed that using 1.0% temephos G at a rate of 2.0 mg/L resulted in 100% mortality against Cx. pipiens larvae by the eighth day after treatment. The residual activity of temephos G was observed to continue for a time; for example 29 days after treatment, average larval mortality rates of >68.0% were observed for both concentrations. At the 50th day after treatment, the mortality rates of the Cx. pipiens larvae were observed to decrease to below 42.7% for both concentrations. Application of temephos G did not have significant effects on the bacteria populations in the septic tanks. Since temephos did not seem to have any major effects on the microorganisms, it was concluded that it is a safe and effective larvicide to use in the septic tanks at a rate of 2.0–5.0 mg/L of 1.0% temephos G.     

Wolbachia infection in the Loxoblemmus complex (Orthoptera: Gryllidae) in Korea

The Wolbachia bacterium is one of the most prevalent intracellular symbionts of invertebrates, particularly insects. This bacterium induces four distinct reproductive anomalies such as cytoplasmic incompatibility, feminization, male killing, and parthenogenesis of its hosts. Here we report that three closely related cricket species, Loxoblemmus doenitzi, L. campestris, and L. equestris can become infected with Wolbachia. Based on the 16s rRNA sequences, all three species were single infections. However, Wolbachia infecting L. campestris showed diverse Wolbachia surface protein gene sequences resembling multiple infections. In addition, all Wolbachia strains in the three host species harbored the Wolbachia specific bacteriophage.     

A Clinical Trial to Evaluate the Efficacy of α-Viniferin in Staphylococcus aureus – Specific Decolonization without Depleting the Normal Microbiota of Nares

Staphylococcus aureus is currently a significant multidrug-resistant bacterium, causing severe healthcare-associated and community-acquired infections worldwide. The current antibiotic regimen against this pathogen is becoming ineffective due to resistance, in addition, they disrupt the normal microbiota. It highlights the urgent need for a pathogen-specific drug with high antibacterial efficacy against S. aureus. α-Viniferin, a bioactive phytochemical compound, has been reported to have excellent anti-Staphylococcus efficacy as a topical agent. However, so far, there were no clinical trials that have been conducted to elucidate its efficacy. The present study aimed to investigate the antibacterial efficacy of α-viniferin against S. aureus in a ten-day clinical trial. Based on the results, α-viniferin showed 50% minimum inhibitory concentrations (MIC₅₀ values) of 7.8 μg/ml in culture broth medium. α-Viniferin was administered in the nares three times a day for ten days using a sterile cotton swab stick. Nasal swab specimens were collected before (0 days) and after finishing the trial (10^th day), and then analyzed. In the culture and RT-PCR-based analysis, S. ureus was reduced significantly: 0.01. In addition, 16S ribosomal RNA-based amplicon sequencing analysis showed that S. aureus reduced from 51.03% to 23.99% at the genus level. RNA-seq analysis was also done to gain insights into molecular mechanisms of α-viniferin against S. aureus, which revealed that some gene groups were reduced in 5-fold FC cutoff at two times MIC conditions. The study results demonstrate α-viniferin as a potential S. aureus-specific drug candidate.