Ravesh Singh

Dr. Ravesh Singh

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 January 2018 in BMC Infectious Diseases
Verified
Journal Article
Open access
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YMYumna Moosa
Yumna Moosa
RTRamla F. Tanko
Ramla F. Tanko
VRVeron Ramsuran
Veron Ramsuran
RSRavesh Singh
Ravesh Singh
MMMashudu Madzivhandila
Mashudu Madzivhandila
WBWendy A. Burgers
Wendy A. Burgers
The majority of people living with HIV require antiretroviral therapy (ART) for controlling viral replication, however there are rare HIV controllers who spontaneously and durably control HIV in the absence of treatment. Understanding what mediates viral control in these individuals has provided us with insights into the immune mechanisms that may be important to induce for a vaccine or functional cure for HIV. To date, few African elite controllers from high incidence settings have been described. We identified virological controllers from the CAPRISA 002 cohort of HIV-1 subtype C infected women in KwaZulu Natal, South Africa, two (1%) of whom were elite controllers. We examined the genetic, clinical, immunological and virological characteristics of these two elite HIV controllers in detail, to determine whether they exhibit features of putative viral control similar to those described for elite controllers reported in the literature. In this case report, we present clinical features, CD4+ T cell and viral load trajectories for two African women over 7 years of HIV infection. Viral load became undetectable 10 months after HIV infection in Elite Controller 1 (EC1), and after 6 weeks in Elite Controller 2 (EC2), and remained undetectable for the duration of follow-up, in the absence of ART. Both elite controllers expressed multiple HLA Class I and II haplotypes previously associated with slower disease progression (HLA-A*74:01, HLA-B*44:03, HLA-B*81:01, HLA-B*57:03, HLA-DRB1*13). Fitness assays revealed that both women were infected with replication competent viruses, and both expressed higher mRNA levels of p21, a host restriction factor associated with viral control. HIV-specific T cell responses were examined using flow cytometry. EC1 mounted high frequency HIV-specific CD8+ T cell responses, including a B*81:01-restricted Gag TL9 response. Unusually, EC2 had evidence of pre-infection HIV-specific CD4+ T cell responses. We identified some features typical of elite controllers, including high magnitude HIV-specific responses and beneficial HLA. In addition, we made the atypical finding of pre-infection HIV-specific immunity in one elite controller, that may have contributed to very early viral control. This report highlights the importance of studying HIV controllers in high incidence settings.

17 January 2020 in Microorganisms
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Journal Article
Open access
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YRYogandree Ramsamy
Yogandree Ramsamy
KMKoleka P. Mlisana
Koleka P. Mlisana
Mushal AllamMushal Allam
Mushal Allam
DADaniel Gyamfi Amoako
Daniel Gyamfi Amoako
Akebe Luther King AbiaAkebe Luther King Abia
Akebe Luther King Abia
SESabiha Yusuf Essack
Sabiha Yusuf Essack
Whole-genome sequence (WGS) analyses were employed to investigate the genomic epidemiology of extensively drug-resistant Klebsiella pneumoniae strains, focusing on the carbapenem resistance-encoding determinants, mobile genetic support, clonal and epidemiological relationships. A total of ten isolates were obtained from patients admitted to the intensive care unit (ICU) in a public hospital in South Africa. Five isolates were from rectal swabs of colonized patients and five from blood cultures of patients with invasive carbapenem-resistant infections. Following microbial identification and antibiotic susceptibility tests, the isolates were subjected to WGS on the Illumina MiSeq platform. All the isolates showed genotypic resistance to tested β-lactams (NDM-1, OXA-1, CTX-M-15, TEM-1B, SHV-1) and other antibiotics. All but one isolate belonged to the ST152 with a novel sequence type, ST3136, differing by a single-locus variant. The isolates had the same plasmid multilocus sequence type (IncF[K12:A-:B36]) and capsular serotype (KL149), supporting the epidemiological linkage between the clones. Resistance to carbapenems in the 10 isolates was conferred by the blaNDM-1 mediated by the acquisition of multi-replicon [ColRNAI, IncFIB(pB171), Col440I, IncFII, IncFIB(K) and IncFII(Yp)] p18-43_01 plasmid. These findings suggest that the acquisition of blaNDM-1-bearing plasmid structure (p18-43_01), horizontal transfer and clonal dissemination facilitate the spread of carbapenemases in South Africa. This emphasizes the importance of targeted infection control measures to prevent dissemination.

19 February 2021 in Sexually Transmitted Infections
Verified
Journal Article
Closed access
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NGNigel Garrett
Nigel Garrett
AMAndile Mtshali
Andile Mtshali
FOFarzana Osman
Farzana Osman
LMLindi Masson
Lindi Masson
LMLyle R McKinnon
Lyle R McKinnon
LLLenine Liebenberg
Lenine Liebenberg
Objectives: STIs cause inflammation that is detrimental for both HIV risk and reproductive health. We assessed the impact of point-of-care (POC) STI testing, immediate treatment and expedited partner therapy (EPT) on genital tract cytokines among a cohort of young South African women.Methods: HIV-negative women underwent POC testing forChlamydia trachomatis(CT),Neisseria gonorrhoeae(NG) andTrichomonas vaginalis(TV) by Xpert CT/NG and OSOM TV, and for bacterial vaginosis (BV) by microscopy. Women with STIs and/or BV received immediate treatment, EPT for STIs and retested after 6 and 12 weeks. Concentrations of 48 cytokines were measured in cervicovaginal fluid at each visit using multiplex ELISA technology. The impact of STI treatment on cytokine concentrations was assessed by multivariable linear mixed models and principal component analysis.Results: The study enrolled 251 women with median age of 23 years (IQR 21–27). The prevalence of CT, NG and TV were 14.3%, 4.4% and 4.0%, and 34.3% had BV. Women with STIs or BV at baseline (n=94) had significantly higher concentrations of pro-inflammatory cytokines (interleukin (IL)-1α, IL-1β, IL-6, tumour necrosis factor (TNF)-α, TNF-β, IL-18 and macrophage inflammatory factor (MIF)) and chemokines (IL-8, IL-16, macrophage inflammatory protein (MIP)-1α, IFN-α2, monokine induced by gamma interferon (MIG), monocyte chemoattractant protein (MCP)-3, regulated on activation normal T cell expressed and secreted and eotaxin) compared with women without (n=157). STI treatment was strongly associated with reduced concentrations of pro-inflammatory cytokines IL-6 (p=0.004), IL-1β (p=0.013), TNF-α (p=0.018) and chemokines MIG (p=0.008) and growth-related oncogene (GRO)-α (p=0.025). A lower Nugent score was associated with a reduction in pro-inflammatory cytokines IL-1α (p=0.003), TNF-related apoptosis-inducing ligand (p=0.004), MIF (p=0.010) and IL-18 (p<0.001), but an increase in chemokines MIG (p=0.020), GRO-α (p<0.001), IP-10 (p<0.001), MIP-1β (p=0.008) and MCP-1 (p=0.005). Principal component analysis showed differences in STI and BV-related inflammatory profiles, but that resolution restored a profile consistent with vaginal health.Conclusions: A comprehensive STI intervention effectively reduced genital inflammation among young women, thereby improving vaginal health and potentially reducing HIV risk.

4 November 2022 in Diagnostics
Verified
Journal Article
Open access
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KBKhethiwe Nomcebo Bhengu
Khethiwe Nomcebo Bhengu
PNPragalathan Naidoo
Pragalathan Naidoo
RSRavesh Singh
Ravesh Singh
NMNozibele Miranda Mpaka - Mbatha
Nozibele Miranda Mpaka - Mbatha
NMNomzamo Nembe Mafa
Nomzamo Nembe Mafa
ZMZilungile Mkhize-Kwitshana
Zilungile Mkhize-Kwitshana
Helminth infections are among the neglected tropical diseases affecting billions of people globally, predominantly in developing countries. Helminths’ effects are augmented by coincident tuberculosis disease, which infects a third of the world’s population. The role of helminth infections on the pathogenesis and pathology of active tuberculosis (T.B.) remains controversial. Parasite-induced suppression of the efficacy of Bacille Calmette-Guerin (BCG) has been widely reported in helminth-endemic areas worldwide. T.B. immune response is predominantly proinflammatory T-helper type 1 (Th1)-dependent. On the other hand, helminth infections induce an opposing anti-inflammatory Th2 and Th3 immune-regulatory response. This review summarizes the literature focusing on host immune response profiles during single-helminth, T.B. and dual infections. It also aims to necessitate investigations into the complexity of immunity in helminth/T.B. coinfected patients since the research data are limited and contradictory. Helminths overlap geographically with T.B., particularly in Sub-Saharan Africa. Each disease elicits a response which may skew the immune responses. However, these effects are helminth species-dependent, where some parasites have no impact on the immune responses to concurrent T.B. The implications for the complex immunological interactions that occur during coinfection are highlighted to inform government treatment policies and encourage the development of high-efficacy T.B. vaccines in areas where helminths are prevalent.

31 January 2020 in Pathogens
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Journal Article
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YRYogandree Ramsamy
Yogandree Ramsamy
KMKoleka P. Mlisana
Koleka P. Mlisana
DADaniel Gyamfi Amoako
Daniel Gyamfi Amoako
Mushal AllamMushal Allam
Mushal Allam
AIArshad Ismail
Arshad Ismail
SESabiha Yusuf Essack
Sabiha Yusuf Essack
Pathogenomic analysis was performed on a novel carbapenem-resistant Citrobacter freundii isolate (H2730R) from a rectal swab of an adult male patient admitted to a tertiary hospital, Durban, South Africa. H2730R was identified using selective media and API 20e kit. Confirmatory identification and antibiotic susceptibility testing were performed using the VITEK II. H2730R was whole-genome sequenced on the Illumina MiSeq platform. H2730R was resistant to all tested antibiotics except tigecycline and was defined as ST498 by the C. freundii multilocus sequence typing (MLST) database. The estimated pathogenic potential predicted a higher probability (Pscore ≈ 0.875), supporting H2730R as a human pathogen. H2730R harbored 25 putative acquired resistance genes, 4 plasmid replicons, 4 intact prophages, a class 1 integron (IntI1), 2 predominant insertion sequences (IS3 and IS5), numerous efflux genes, and virulome. BLASTn analysis of the blaNDM-1 encoding contig (00022) and its flanking sequences revealed the blaNDM-1 was located on a plasmid similar to the multireplicon p18-43_01 plasmid reported for the spread of carbapenem resistance in South Africa. Phylogenomic analysis showed clustering of H2730R with CF003/CF004 strains in the same clade, suggesting a possible association between C. freundii strains/clones. Acquiring the p18-43_01 plasmid containing blaNDM-1, the diversity, and complex resistome, virulome, and mobilome of this pathogen makes its incidence very worrying regarding mobilized resistance. This study presents the background genomic information for future surveillance and tracking of the spread of carbapenem-resistant Enterobacteriaceae in South Africa.

5 January 2023 in African Journal of Laboratory Medicine
Verified
Journal Article
Open access
NMNomonde R. Mvelase
Nomonde R. Mvelase
LCLindiwe Cele
Lindiwe Cele
RSRavesh Singh
Ravesh Singh
YNYeshnee Naidoo
Yeshnee Naidoo
JGJennifer Giandhari
Jennifer Giandhari
KMKoleka P. Mlisana
Koleka P. Mlisana
Background: Rifampicin resistance missed by commercial rapid molecular assays but detected by phenotypic assays may lead to discordant susceptibility results and affect patient management.Objective: This study was conducted to evaluate the causes of rifampicin resistance missed by the GenoType MTBDRplus and its impact on the programmatic management of tuberculosis in KwaZulu-Natal, South Africa.Methods: We analysed routine tuberculosis programme data from January 2014 to December 2014 on isolates showing rifampicin susceptibility on the GenoType MTBDRplus assay but resistance on the phenotypic agar proportion method. Whole-genome sequencing was performed on a subset of these isolates.Results: Out of 505 patients with isoniazid mono-resistant tuberculosis on the MTBDRplus, 145 (28.7%) isolates showed both isoniazid and rifampicin resistance on the phenotypic assay. The mean time from MTBDRplus results to initiation of drug-resistant tuberculosis therapy was 93.7 days. 65.7% of the patients had received previous tuberculosis treatment. The most common mutations detected in the 36 sequenced isolates were I491F (16; 44.4%) and L452P (12; 33.3%). Among the 36 isolates, resistance to other anti-tuberculosis drugs was 69.4% for pyrazinamide, 83.3% for ethambutol, 69.4% for streptomycin, and 50% for ethionamide.Conclusion: Missed rifampicin resistance was mostly due to the I491F mutation located outside the MTBDRplus detection area and the L452P mutation, which was not included in the initial version 2 of the MTBDRplus. This led to substantial delays in the initiation of appropriate therapy. The previous tuberculosis treatment history and the high level of resistance to other anti-tuberculosis drugs suggest an accumulation of resistance.