Omar Siddiqi

Dr. Omar Siddiqi

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Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

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

Representative Publications

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25 March 2014 in Clinical Infectious Diseases
Verified
Journal Article
Open access
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OSOmar Siddiqi
Omar Siddiqi
MGMusie Ghebremichael
Musie Ghebremichael
XDXin Dang
Xin Dang
MAMasharip Atadzhanov
Masharip Atadzhanov
PKPatrick Kaonga
Patrick Kaonga
IKIgor J. Koralnik
Igor J. Koralnik
This is the first comprehensive study in sub-Saharan Africa looking at the full spectrum of central nervous system opportunistic infections in the HIV population. This study highlights that multiple pathogens are often present in the cerebrospinal fluid of individuals living with HIV. Background. Knowledge of central nervous system (CNS) opportunistic infections (OIs) among people living with human immunodeficiency virus (HIV) in sub-Saharan Africa is limited. Methods. We analyzed 1 cerebrospinal fluid (CSF) sample from each of 331 HIV-infected adults with symptoms suggestive of CNS OI at a tertiary care center in Zambia. We used pathogen-specific primers to detect DNA from JC virus (JCV), varicella zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV) types 1 and 2, Mycobacterium tuberculosis, and Toxoplasma gondii via real-time polymerase chain reaction (PCR). Results. The patients' median CD4+ T-cell count was 89 cells/µL (interquartile range, 38–191 cells/µL). Of 331 CSF samples, 189 (57.1%) had at least 1 pathogen. PCR detected DNA from EBV in 91 (27.5%) patients, M. tuberculosis in 48 (14.5%), JCV in 20 (6.0%), CMV in 20 (6.0%), VZV in 13 (3.9%), HSV-1 in 5 (1.5%), and HSV-2 and T. gondii in none. Fungal and bacteriological studies showed Cryptococcus in 64 (19.5%) patients, pneumococcus in 8 (2.4%), and meningococcus in 2 (0.6%). Multiple pathogens were found in 68 of 189 (36.0%) samples. One hundred seventeen of 331 (35.3%) inpatients died during their hospitalization. Men were older than women (median, 37 vs 34 years; P = .01), more recently diagnosed with HIV (median, 30 vs 63 days; P = .03), and tended to have a higher mortality rate (40.2% vs 30.2%; P = .07). Conclusions. CNS OIs are frequent, potentially treatable complications of AIDS in Zambia. Multiple pathogens often coexist in CSF. EBV is the most prevalent CNS organism in isolation and in coinfection. Whether it is associated with CNS disease or a marker of inflammation requires further investigation. More comprehensive testing for CNS pathogens could improve treatment and patient outcomes in Zambia.

1 March 2010 in Journal of the Neurological Sciences
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Journal Article
Closed access
OSOmar Siddiqi
Omar Siddiqi
MAMasharip Atadzhanov
Masharip Atadzhanov
GBGretchen L. Birbeck
Gretchen L. Birbeck
IKIgor J. Koralnik
Igor J. Koralnik

1 August 2019 in Journal of Clinical Microbiology
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Journal Article
Closed access
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OSOmar Siddiqi
Omar Siddiqi
GBGretchen L. Birbeck
Gretchen L. Birbeck
MGMusie Ghebremichael
Musie Ghebremichael
EMEugene Mubanga
Eugene Mubanga
SLShawn Love
Shawn Love
IKIgor J. Koralnik
Igor J. Koralnik
Tuberculous meningitis (TBM) is a devastating infection of the central nervous system lacking an adequate point-of-care diagnostic test. We conducted a prospective cohort study of 550 Zambian adults with suspected TBM to determine the diagnostic accuracy of cerebrospinal fluid (CSF) Xpert MTB/RIF, CSF lipoarabinomannan (LAM), urine LAM, CSF total protein, and CSF glucose compared with the gold standard of CSF culture.

9 May 2013 in Current Treatment Options in Neurology
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Journal Article
Closed access
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OSOmar Siddiqi
Omar Siddiqi
GBGretchen L. Birbeck
Gretchen L. Birbeck

26 February 2020 in Wellcome Open Research
Verified
Journal Article
Open access
SMSuzaan Marais
Suzaan Marais
RTRonald Van Toorn
Ronald Van Toorn
FCFelicia C. Chow
Felicia C. Chow
AMAbi Manesh
Abi Manesh
OSOmar Siddiqi
Omar Siddiqi
RARob E. Aarnoutse
Rob E. Aarnoutse
Tuberculous intracranial mass lesions are common in settings with high tuberculosis (TB) incidence and HIV prevalence. The diagnosis of such lesions, which include tuberculoma and tuberculous abscesses, is often presumptive and based on radiological features, supportive evidence of TB elsewhere and response to TB treatment. However, the treatment response is unpredictable, with lesions frequently enlarging paradoxically or persisting for many years despite appropriate TB treatment and corticosteroid therapy. Most international guidelines recommend a 9-12 month course of TB treatment for central nervous system TB when the infecting Mycobacterium tuberculosis ( M.tb ) strain is sensitive to first-line drugs. However, there is variation in opinion and practice with respect to the duration of TB treatment in patients with tuberculomas or tuberculous abscesses. A major reason for this is the lack of prospective clinical trial evidence. Some experts suggest continuing treatment until radiological resolution of enhancing lesions has been achieved, but this may unnecessarily expose patients to prolonged periods of potentially toxic drugs. It is currently unknown whether persistent radiological enhancement of intracranial tuberculomas after 9-12 months of treatment represents active disease, inflammatory response in a sterilized lesion or merely revascularization. The consequences of stopping TB treatment prior to resolution of lesional enhancement have rarely been explored. These important issues were discussed at the 3 rd International Tuberculous Meningitis Consortium meeting. Most clinicians were of the opinion that continued enhancement does not necessarily represent treatment failure and that prolonged TB therapy was not warranted in patients presumably infected with M.tb strains susceptible to first-line drugs. In this manuscript we highlight current medical treatment practices, benefits and disadvantages of different TB treatment durations and the need for evidence-based guidelines regarding the treatment duration of patients with intracranial tuberculous mass lesions.

31 October 2019 in Wellcome Open Research
Verified
Journal Article
Open access
SMSuzaan Marais
Suzaan Marais
RTRonald Van Toorn
Ronald Van Toorn
FCFelicia C. Chow
Felicia C. Chow
AMAbi Manesh
Abi Manesh
OSOmar Siddiqi
Omar Siddiqi
TCTuberculous Meningitis International Research Consortium
Tuberculous Meningitis International Research Consortium
Tuberculous intracranial mass lesions are common in settings with high tuberculosis (TB) incidence and HIV prevalence. The diagnosis of such lesions, which include tuberculoma and tuberculous abscesses, is often presumptive and based on radiological features, supportive evidence of TB elsewhere and response to TB treatment. However, the treatment response is unpredictable, with lesions frequently enlarging paradoxically or persisting for many years despite appropriate TB treatment and corticosteroid therapy. Most international guidelines recommend a 9-12 month course of TB treatment for central nervous system TB when the infectingMycobacterium tuberculosis(M.tb) strain is sensitive to first-line drugs. However, there is variation in opinion and practice with respect to the duration of TB treatment in patients with tuberculomas or tuberculous abscesses. A major reason for this is the lack of prospective clinical trial evidence. Some experts suggest continuing treatment until radiological resolution of enhancing lesions has been achieved, but this may unnecessarily expose patients to prolonged periods of potentially toxic drugs. It is currently unknown whether persistent radiological enhancement of intracranial tuberculomas after 9-12 months of treatment represents active disease, inflammatory response in a sterilized lesion or merely revascularization. The consequences of stopping TB treatment prior to resolution of lesional enhancement have rarely been explored. These important issues were discussed at the 3rdInternational Tuberculous Meningitis Consortium meeting. Most clinicians were of the opinion that continued enhancement does not necessarily represent treatment failure and that prolonged TB therapy was not warranted in patients presumably infected withM.tbstrains susceptible to first-line drugs. In this manuscript we highlight current medical treatment practices, benefits and disadvantages of different TB treatment durations and the need for evidence-based guidelines regarding the treatment duration of patients with intracranial tuberculous mass lesions.