Detection, isolation, and characterization of chikungunya viruses associated with the Pakistan outbreak of 2016-2017.

The chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus, which has infected millions of people in Africa, Asia, Americas, and Europe since it reemerged in India and Indian Ocean regions in 2005-2006. Starting in the middle of November 2016, CHIKV has been widely spread, and more than 4,000 cases of infections in humans were confirmed in Pakistan. Here, we report the first isolation and characterization of CHIKV from the Pakistan outbreak. Eight CHIKV strains were newly isolated from human serum samples using a cell culture procedure. A full-length genome sequence and eight complete envelope (E1) sequences of CHIKV from Pakistan were obtained in this study. Alignment of the CHIKV E1 sequences revealed that the eight new CHIKV isolates were highly homogeneous, with only two nonsynonymous substitutions found at generally conserved sites (E99 and Q235). Based on the comparison of 342 E1 sequences, the two nonsynonymous mutations were located in well-recognized domains associated with viral functions such as the cell fusion and vector specificity, suggesting their potential functional importance. Phylogenetic analysis indicated that the CHIKV strains from Pakistan originated from CHIKV circulating in the Indian region. This study helps elucidate the epidemics of CHIKV in Pakistan and also provides a foundation for studies of evolution and expansion of CHIKV in South Asia.

Acute and sub-chronic toxicity of tetrandrine in intravenously exposed female BALB/c mice.

OBJECTIVE: To evaluate the acute and sub-chronic toxicity of intravenously administered tetrandrine (TET) in female BALB/c mice. METHODS: The median lethal dose (LD50) of intravenously administered TET was calculated in mice using Dixon's up-and-down method. In the acute toxicity study, mice were intravenously administered with TET at a single dose of 20, 100, 180, 260 and 340 mg/kg, respectively and were evaluated at 14 days after administration. In the sub-acute toxicity study, mice were intravenously administered various doses of TET (30, 90 and 150 mg/kg) each day for 14 consecutive days. Clinical symptoms, mortality, body weight, serum biochemistry, organ weight and histopathology were examined at the end of the experiment, as well as after a 1-week recovery period. RESULT: LD50 was found to be 444.67±35.76 mg/kg. In the acute toxicity study, no statistically signifificant differences in body weight, blood biochemistry, or organ histology were observed between the administration and control groups when mice were intravenously administered with single dose at 20, 100, 180, 260 and 340 mg/kg of TET (P >0.05). In the sub-acute toxicity study, no signifificant changes in body weight, biochemistry and organ histology were observed with up to 90 mg/kg of TET compared with the control group (P >0.05), however, in the 150 mg/kg administered group, TET induced transient toxicity to liver, lungs and kidneys, but withdrawal of TET can lead to reversal of the pathological conditions. CONCLUSIONS: The overall fifindings of this study indicate that TET is relatively non-toxic from a single dose of 20, 100, 180, 260 or 340 mg/kg, and that up to 90 mg/kg daily for 14 consecutive days can be considered a safe application dose.

Synergistic effects of tetrandrine on the antifungal activity of topical ketoconazole cream in the treatment of dermatophytoses: a clinical trial.

OBJECTIVE: To evaluate the synergistic effects of tetrandrine (TET) on the antifungal activity of topical ketoconazole (KCZ) in the treatment of dermatophytoses. METHODS: The minimum inhibitory concentrations (MICs) for KCZ and combined KCZ and TET were compared in vitro. A randomized, double-blind trial was conducted among 97 patients with dermatophytoses who were assigned to 3 groups and received: treatment with combination of 2% KZC and 2% TET cream (KCZ + TET group), or only 2% KZC cream (KCZ group), or 2% TET cream (TET group). Patients with tinea corporis and/or tinea cruris were treated for 2 weeks, separately. The patients with tinea pedis and/or tinea manuum were treated for 4 weeks. RESULTS: Compared with KZC alone, combined use of KZC and TET showed lower MICs against clinical isolates of dermatophytes (P<0.05 for all). In the patients with tinea corporis and/or tinea cruris, the rates of overall cure (clinical cure plus mycologic clearance) were 81.25% vs. 33.33% for combined treatment and KZC monotherapy, respectively, after 4 weeks. All clinical indices were significantly different between the combination therapy and only KCZ therapy groups (P<0.05). Among the patients with tinea pedis and/or tinea manuum after 4 weeks treatment, the overall cure rates in the KCZ + TET group and KCZ group were 75.00% vs. 40.00%, respectively. In the KCZ + TET group, all the clinical indices were significantly better than those in the KCZ group and TET group (P<0.05). The rates of overall efficacy in the TET group were all zero. No local skin redness or itching was observed during TET treatment. No clinically significant changes were found in post-treatment routine blood, urine, or stool tests, ECG, or tests for liver and kidney function; no serious adverse events occurred. CONCLUSION: TET synergistically enhanced the clinical efficacy of topical KZC cream in the treatment of dermatophytoses.

Genome sequence of the milbemycin-producing bacterium Streptomyces bingchenggensis.

Streptomyces bingchenggensis is a soil-dwelling bacterium producing the commercially important anthelmintic macrolide milbemycins. Besides milbemycins, the insecticidal polyether antibiotic nanchangmycin and some other antibiotics have also been isolated from this strain. Here we report the complete genome sequence of S. bingchenggensis. The availability of the genome sequence of S. bingchenggensis should enable us to understand the biosynthesis of these structurally intricate antibiotics better and facilitate rational improvement of this strain to increase their titers.