Characteristics of genotype, drug resistance, and molecular transmission network among newly diagnosed HIV-1 infections in Shenzhen, China

The HIV-1 pandemic has persisted for four decades, and poses a major challenge to global public health. Shenzhen, a city with large number of migrant populations in China, is suffering HIV-1 epidemic. It is necessary to continuously conduct the molecular surveillance among newly diagnosed HIV-1 patients in these migrant population. In this study, plasma samples of newly diagnosed and ART-naive HIV-1 infections were collected from Shenzhen city in China. The partial genes of HIV-1 gag and pol were amplified and sequenced for the analysis of genotype, drug resistance, and molecular transmission network. Ninety-one sequences of pol gene were obtained from newly diagnosed HIV-1 infections in Shenzhen, and seven HIV-1 subtypes were revealed in this investigation. Among them, the circulating recombinant form (CRF) 07_BC was the mostly frequent subtype (53.8%, 49/91), followed by CRF01_AE (20.9%, 19/91), CRF55_01B (9.9%, 9/91), unique recombinant forms (URFs) (8.8%, 8/91), B (3.3%, 3/91), CRF59_01B (2.2%, 2/91), and CRF08_BC (1.1%, 1/91). The overall prevalence of pretreatment drug resistance (PDR) was 23.1% (21/91), and 52.38% (11/21) of the PDR was specific for the nonnucleotide reverse transcriptase inhibitors (NNRTIs). Furthermore, a total of 3091 pol gene sequences were used to generate 19 molecular transmission clusters, and then one growing cluster, a new cluster, and a cluster with growth reactivation were identified. The result revealed that more sexual partner, CRF_07BC subtype, and seven amino acid deletions in gag p6 region might be the influencing factors associated with the high risk of transmission behavior. Compared with CRF01_AE subtype, CRF07_BC subtype strains were more likely to form clusters in molecular transmission network. This suggests that long-term surveillance of the HIV-1 molecular transmission should be a critical measure to achieve a precise intervention for controlling the spread of HIV-1 in China.

First Report of Blastocystis spp. Infection in Pet Birds in Henan Province, Central China

Blastocystis spp. are common intestinal parasites found in humans and many kinds of animals. Blastocystis spp. infection is associated with a variety of symptoms, including diarrhea, abdominal pain, and chronic urticaria, among which asymptomatic infection is the most common. Among the 11 potentially zoonotic subtypes of Blastocystis spp., 9 subtypes have been reported in bird species. The purpose of this study was to detect the infection rate and gene subtype distribution of Blastocystis spp. in pet birds in Henan Province, Central China, to provide a foundation for preventing and controlling Blastocystis spp. in pet birds. Fecal DNA was extracted from 382 fresh fecal samples of pet birds collected from five areas in Henan Province, Central China. Twenty-three species of pet birds from four orders, from local pet trading markets, parks, and individuals, were sampled. All DNA samples were investigated by PCR, and positive samples were sequenced to analyze the gene subtypes based on the small ribosomal subunit (SSU rRNA) gene. Blastocystis spp. was detected in 0.8% of the samples. Further DNA sequencing and phylogenetic analyses resulted in the identification of two known zoonotic subtypes, ST1 (n = 2) and ST7 (n = 1). As far as we know, this is the first time that ST1 subtype has been reported in Chinese birds. It is found that pet birds may be the hosts of zoonotic Blastocystis spp. subtypes, and the role of birds in transmitting Blastocystis spp. to humans needs to be further studied.

HIV-1 molecular transmission network among sexually transmitted populations in Liaoning Province, China

INTRODUCTION

In recent years, with the development of molecular epidemiology, molecular transmission networks based on evolutionary theory and sequence analysis have been widely used in research on human immunodeficiency virus (HIV)-1 transmission dynamics and precise intervention for high-risk populations. The HIV-1 molecular transmission network is a new method to study the population's access to the network, the characteristics of clustering, and the characteristics of interconnection in the network. Here, we analyzed the characteristics of the HIV-1 molecular transmission network of sexually transmitted people in Liaoning Province.

METHODS

A study of HIV-infected persons who were sexually transmitted in Liaoning Province from 2003 to 2019. HIV-1 RNA was extracted, amplified and sequenced, and a phylogenetic tree was constructed to determine the subtype using the well matched pol gene region sequence. The gene distance between sequences was calculated, the threshold was determined, and the molecular transmission network was constructed.

RESULTS

109 samples of pol gene region were obtained. The main subtype of HIV-1 was CRF01_AE, followed by B, CRF07_BC, etc. 12.8% of them were resistant to HIV. At the threshold of 0.55 gene distance, 60.6% of them entered the HIV-1 molecular transmission network. Workers, sample source voluntary counseling and testing, other testing, subtype B and drug resistance are the factors influencing the access to HIV-1 molecular transmission network. The subtype of CRF01_AE formed 6 clusters in the molecular transmission network. In the network, the difference of connection degree between different subtypes was statistically significant.

DISCUSSION

The three subtypes CRF01_AE, CRF07_BC and B that enter the molecular transmission network do not have interconnections, and they form clusters with each other. It shows that the risk of transmission among the three subtypes is less than the risk of transmission within each subtype. The factors affecting HIV-1 entry into the molecular transmission network were occupation, sample source, genotype and drug resistance. The L33F mutation at the HIV-1 resistance mutation site constitutes the interconnection in the largest transmission cluster in the network. The epidemiological characteristics of HIV-infected persons in each molecular transmission cluster show that 97% of the study subjects come from the same area and have a certain spatial aggregation.

CONCLUSION

Constructing a molecular transmission network and conducting long-term monitoring, while taking targeted measures to block the spread of HIV can achieve precise prevention and control.

Cockroach as a Vector of Blastocystis sp. is Risk for Golden Monkeys in Zoo

Blastocystis sp. is a kind of protozoa living in the intestinal tract of human and animals, which will cause intestinal diseases such as diarrhea, abdominal distension and vomiting. This paper was aimed to understand the infection of Blastocystis sp. In golden monkeys and the transmission path in North China. Thirty-seven feces samples from golden monkeys and 116 cockroach samples from Shijiazhuang Zoo were collected from July to October 2019 for PCR analysis of Blastocystis sp. Genetic diversity analysis was further conducted on the samples with positive PCR results. The results showed that the infection rate was 48.7% (18/37) in golden monkeys and 82.8% (96/116) in cockroaches, respectively. The genetic evolution analysis based on small subunit ribosomal RNA demonstrated that three subtypes (ST) of Blastocystis sp. including ST1, ST2, and ST3 existed in the intestinal tract of golden monkeys, while only ST2 was detected in the intestinal tract of cockroaches. This paper may provide supports for the quarantine and control of Blastocystis sp. for the zoo in Northern China.

Gene subtype analysis of Treponema pallidum for drug resistance to azithromycin

Azithromycin has been widely used for the treatment of Treponema pallidum. However, the drug resistance of T. pallidum for azithromycin is currently increasing. The aim of the present study was to analyze the association between gene subtypes of T. pallidum and drug resistance for azithromycin. The gene subtypes of T. pallidum were assayed by a polymerase chain reaction technique. Drug resistance of T. pallidum was analyzed using an antimicrobial susceptibility test. The results demonstrated that gene type tpr presented higher drug resistance compared with arp and tp0548 gene types of T. pallidum. Gene type tpr was identified as eight gene subtypes (14a/f, 14e/f, 12e/f, 12d/f, 6d/f, 11d/f, 14j/f and 8d/f) among 324 cases. It was identified that 23S rRNA A2058G mutation was observed in gene subtypes 14a/f, 14e/f and 12e/f. A2059G mutation occurred in the gene subtypes 8d/f, 12d/f, 6d/f, 11d/f and 14j/f. The proportions of azithromycin-resistant genotypes harboring either the A2058G or the A2059G mutation among the T. pallidum strains were 34.2 and 65.8%, respectively. The antimicrobial susceptibility test demonstrated that A2059G mutations exhibited a higher drug resistance for azithromycin compared with A2058G mutations. In conclusion, these results indicate that azithromycin resistance in T. pallidum is associated with gene subtype, which may contribute to the treatment of T. pallidum.