HIV-1 genetic diversity, geographical linkages and antiretroviral drug resistance among individuals from Pakistan

Identification of a novel first-generation HIV-1 circulating recombinant form (CRF152_DG) among people living with HIV in Karachi, Pakistan

The objective of this study was to characterize a novel circulating recombinant form of human immunodeficiency virus type 1 (HIV-1) among people living with HIV in Karachi, Pakistan. We conducted near-full-length genome (NFLG) sequencing on eight samples exhibiting D/G recombination signals in the pol gene region. We successfully obtained NFLG sequences (790-9,614; with reference to the HXB2 genome) from four of the eight samples and then conducted phylogenetic and recombination analyses on them. The four NFLG sequences from our study and one DG unique recombinant form previously identified in the United Kingdom (GenBank accession: MF109700) formed a distinct monophyletic cluster with an Shimodaira-Hasegawa approximate likelihood ratio test node support value of 100%. Bootscan analyses of the five NFLG sequences of DG recombinants showed that all five NFLGs shared the same unique mosaic pattern of recombination breakpoints between D and G clades, with two D fragments in the pol and vif regions inserted into a G backbone. Subregion phylogenetic analyses confirmed these sequences to be a novel circulating recombinant form (CRF) composed of subtypes D and G. The DG recombinant sequences were eventually designated as CRF152_DG by the Los Alamos HIV Sequence Database staff.

IMPORTANCE

In Pakistan, the genetic diversity of human immunodeficiency virus type 1 (HIV-1) is becoming increasingly complex, compared to the early years of the epidemic that started after the detection of the first cases of HIV-1 in 1987 in Karachi. Based on the available molecular studies, two dominant HIV-1 clades, sub-subtype A1 and CRF02_AG, have been found to co-circulate with other clades, namely B, C, D, G, CRF01_AE, CRF35_A1D, and CRF56_cpx, in various urban areas of Pakistan. Several novel recombinant forms have also been detected. This first report of CRF152_DG highlights the complex nature of the HIV epidemic in Pakistan and emphasizes the importance of continual molecular surveillance (ideally based on whole-genome sequences) of HIV.

Genetic and antiretroviral drug resistance mutations analysis of reverse transcriptase and protease gene from Pakistani people living with HIV-1

BACKGROUND

Antiretroviral therapy (ART) effectiveness is compromised by the emergence of HIV drug resistance mutations (DRM) and can lead to the failure of ART. Apart from intrinsic viral factors, non-compliance with drugs and/or the use of sub-optimum therapy can lead to the emergence of DRMs. In Pakistan HIV currently exists as a concentrated epidemic, however, ART coverage is very low, and drug adherence is poor. ART is selected assuming without baseline genotyping. Pakistan has recently seen a rise in treatment failures, but the country's actual burden of DRM is still unknown. In this study, we perform the genetic and drug resistance analysis of the pol gene from Pakistani HIV-positive ART-naïve and ART-experienced individuals.

METHODS

In this study, HIV-1 pol was sequenced from 146 HIV-1 positive individuals, divided into ART-naïve (n = 37) and ART-experienced (n = 109). The sequences were also used to determine HIV-1 subtypes, the prevalence of DRM, and pol genetic variability.

RESULTS

DRM analysis identified numerous DRMs against reverse transcriptase inhibitors in both ART-naïve and ART-experienced groups, including a few that are classified as rare. Additionally, the ART-experienced group showed mutations associated with resistance to protease inhibitors. Genetic analysis showed negative selection pressure in both groups, but a higher rate of evolution in the ART-naïve group.

CONCLUSION

High prevalence of DRMs, especially against previous first-line treatment in ART- naïve and the accumulation of DRMs in ART-experienced groups is concerning and warrants that a more extensive DRM survey be carried out to inform first-line and second-line ART regimen recommendations.

HIV and Drug-Resistant Subtypes

Acquired Immunodeficiency Syndrome (AIDS) is a human viral infectious disease caused by the positive-sense single-stranded (ss) RNA Human Immunodeficiency Virus (HIV) (Retroviridae family, Ortervirales order). HIV-1 can be distinguished into various worldwide spread groups and subtypes. HIV-2 also causes human immunodeficiency, which develops slowly and tends to be less aggressive. HIV-2 only partially homologates to HIV-1 despite the similar derivation. Antiretroviral therapy (ART) is the treatment approved to control HIV infection, based on multiple antiretroviral drugs that belong to different classes: (i) NNRTIs, (ii) NRTIs, (iii) PIs, (iv) INSTIs, and (v) entry inhibitors. These drugs, acting on different stages of the HIV life cycle, decrease the patient's total burden of HIV, maintain the function of the immune system, and prevent opportunistic infections. The appearance of several strains resistant to these drugs, however, represents a problem today that needs to be addressed as best as we can. New outbreaks of strains show a widespread geographic distribution and a highly variable mortality rate, even affecting treated patients significantly. Therefore, novel treatment approaches should be explored. The present review discusses updated information on HIV-1- and HIV-2-resistant strains, including details on different mutations responsible for drug resistance.

Phylogenetic and Drug-Resistance Analysis of HIV-1 Sequences From an Extensive Paediatric HIV-1 Outbreak in Larkana, Pakistan

Introduction

In April 2019, an HIV-1 outbreak among children occurred in Larkana, Pakistan, affecting more than a thousand children. It was assumed that the outbreak originated from a single source, namely a doctor at a private health facility. In this study, we performed subtype distribution, phylogenetic and drug-resistance analysis of HIV-1 sequences from 2019 outbreak in Larkana, Pakistan.

Methods

A total of 401 blood samples were collected between April–June 2019, from children infected with HIV-1 aged 0–15 years recruited into a case-control study to investigate the risk factors for HIV-1 transmission. Partial HIV-1 pol sequences were generated from 344 blood plasma samples to determine HIV-1 subtype and drug resistance mutations (DRM). Maximum-likelihood phylogenetics based on outbreak and reference sequences was used to identify transmission clusters and assess the relationship between outbreak and key population sequences between and within the determined clusters. Bayesian analysis was employed to identify the time to the most recent common recent ancestor (tMRCA) of the main Pakistani clusters.

Results

The HIV-1 circulating recombinant form (CRF) 02_AG and subtype A1 were most common among the outbreak sequences. Of the treatment-naïve participants, the two most common mutations were RT: E138A (8%) and RT: K219Q (8%). Four supported clusters within the outbreak were identified, and the median tMRCAs of the Larkana outbreak sequences were estimated to 2016 for both the CRF02_AG and the subtype A1 clusters. Furthermore, outbreak sequences exhibited no phylogenetic mixing with sequences from other high-risk groups of Pakistan.

Conclusion

The presence of multiple clusters indicated a multi-source outbreak, rather than a single source outbreak from a single health practitioner as previously suggested. The multiple introductions were likely a consequence of ongoing transmission within the high-risk groups of Larkana, and it is possible that the so-called Larkana strain was introduced into the general population through poor infection prevention control practices in healthcare settings. The study highlights the need to scale up HIV-1 prevention programmes among key population groups and improving infection prevention control in Pakistan.

Rising HIV seroconversion rates & associated risks among employees of organization 'X': A case control study, Pakistan, 2017

Background and Objectives:

In 2004 Pakistan escalated from ‘low-prevalence’ to ‘concentrated’ phase of HIV epidemic. Despite global decline in HIV incidence since 1997, rate of HIV infections in Pakistan is persistently rising since 1990. Available literature focusses on key populations or localized outbreaks limited by short study duration and regional applicability of results. We studied HIV seroconversion trends over a period of 8 years in a geographically diverse population and evaluated associated risk factors.

Methods:

A desk review of HIV surveillance data from 2010 to 2017 was carried out at Armed Forces Institute of Pathology. A case was defined as any adult employed in organization ‘X’, initially screened for HIV but later seroconverted on ELISA and western blot. Case-control study was conducted on cases diagnosed in 2017. Age and sex matched controls were identified from same population sub-group. Structured telephonic interviews were conducted and statistical analysis done at 5% margin of error.

Results:

The annual HIV diagnosis rate remained relatively stable till 2015 (< 40 /100,000/yr) after which it rose sharply to 60/100,000/yr in 2016 .Upward trend continued in 2017 to reach 125/100,000/yr (>200% increase from baseline). Acquisition of HIV was significantly associated with commercial sex activities (OR=9; 95% CI: 1.25-395).

Conclusion:

HIV seroconversion rates among employees of organization X have increased significantly in the past two years. Unlike HIV outbreaks previously reported from Pakistan, sexual route seems to be the predominant mode of transmission. Focus is mandated on prevention of sexual transmission of HIV at national level as well for all vulnerable populations.

Diverse HCV Strains And HIV URFS Identified Amongst People Who Inject Drugs In India

Although the prevalences of HIV and HCV are significantly higher amongst PWID in India compared to the general population, the strains circulating within this group have not been well-characterized. Through subgenomic sequencing of viruses present in residual plasma from an HIV/HCV prevalence study conducted amongst PWID across five cities in India in 2016-2017, a total of N = 498 HCV and N = 755 HIV strains were classified from N = 975 study participants. Considerable HCV diversity was identified, with different strains predominating in each region of the country. Overall, the most common strain was genotype 3a (39.0%), with genotypes 1a (26.9%), 1b (3.0%), 1c (0.2%), 3b (20.7%), 3i (2.0%), 4a (0.2%), 4d (1.0%), 6 (1.8%), 6n (4.8%), 6 v (0.2%) and one unclassifiable recombinant specimen (0.2%) also identified. The majority of the HIV specimens were subtype C (96.7%), although subtype A (0.4%), CRF01_AE (0.4%) and unique recombinant forms (URFs, 2.5%) were also detected. Notably, the geographical restriction of HIV subtype A and CRF01_AE, and HCV genotypes 4 and 6 to specific sites suggests distinct novel introductions of HIV and HCV into PWID populations, potentially via drug trafficking routes from neighboring countries where these strains are common.

Circulation of multiple subtypes (A, G and CRFs 02_AG) of human immunodeficiency virus type 1 (HIV-1) in selected districts of Punjab province, Pakistan

Owing to consistent genetic mutation and recombination, various escape mutants and/or drug-resistant mutants of human immunodeficiency virus (HIV-1) are now emerging worldwide. Therefore, an understanding of the genetic characteristics of prevailing strains, particularly with regard to drug-resistance-associated substitutions, is essential for devising and implementing treatments and disease control interventions in endemic settings such as Pakistan. We processed a total of 130 plasma samples originating from HIV-treatment centers in selected districts of Punjab province, Pakistan. The samples were first screened using an HIV-1 Ag/Ab Combo test followed by amplification of the pol gene (1084 bp) from samples that were positive either for the antigen or for both the antigen and antibodies simultaneously. Screening revealed that a total of 45 samples were positive (34.62%; 95% CI: 26.99-43.13) for either antigen or both antigen and antibodies (n = 18, 40%; 95% CI: 27.02-54.55) or for antibodies alone (n = 27, 60%; 95% CI: 45.45-72.98). A largest number of positive samples was from the district of Lahore (n = 19/43, 44.18%; 95% CI: 30.44-58.9) followed by Faisalabad (n= 12/36, 33.33%; 95% CI: 20.21-49.66), Gujranwala (n = 05/23, 21.7%; 95% CI: 9.66-41.9) and Sargodha (n = 09/28, 32.1%; 95% CI: 17.93-50.66). The probability of occurrence of HIV infection was significantly associated with individuals having a history of injecting drug use (68.08%; OR = 11.15; 95% CI: 53.84-79.61, p = 0.0001). Phylogenetic analysis based on the pol gene showed that the sequences from this study clustered into three distinct clades representing recombinant form 02_AG (n = 14, 77.0%; 95% CI: 54.79-91.00), and subtypes A (n = 2, 11.1%; 95% CI: 3.1-32.8) and G (n = 2, 11.1%; 95% CI: 3.1-32.8). Although we screened 18 samples for drug-resistance-associated mutations, except for an accessory mutation (M46K) in the protease (PR) region in one subject, we found a lack of drug-resistance-associated substitutions in the PR region. On the other hand, we found two subjects (2/18) carrying a resistance-associated mutation (V106I) conferring a low level of resistance against non-nucleoside reverse transcriptase inhibitors. The present study shows that multiple subtypes of HIV-1 are present in the affected population. Continuous disease surveillance coupled with evaluation of drug resistance at higher resolution should be done in future studies.