Browsing by Author "Han, Aaron"

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Detection of OXA-23, GES-11 and NDM-1 among carbapenem-resistant Acinetobacter baumannii in Dubai: A preliminary study
(2021) Han, Aaron
Letter to Editor: Acinetobacter baumannii is a Gram-negative organism that has become a significant offender in health-care facilities, with the worldwide spread of carbapenem-resistant Acinetobacter baumannii (CRAB) significantly debilitating treatment options. Acquired carbapenemases of Ambler class D, or oxacillinases, namely OXA23-like, OXA-24-like, OXA-58-like, OXA-143-like and OXA-235-like groups, have been largely described in CRAB. Non-OXA carbapenemases are also acquired by A. baumannii, including metallo-β-lactamases of Ambler class B, such as the NDM-group, as well as Ambler class A carbapenemases, KPC and GES [1]. Intrinsically, two β-lactam hydrolysing enzyme groups occur in CRAB, OXA-51 and Acinetobacter-derived cephalosporinases (ADCs). While these two intrinsic enzyme categories secure weak carbapenem hydrolysis, acquisition of insertion sequence (IS) elements such as ISAba1 upstream of blaOXA-51 and blaADC may lead to enhanced expression, increasing resistance to cephalosporins, but only minimally to carbapenems. The existence of ISAba1 upstream of acquired blaOXA-23 enhances expression, resulting in higher carbapenem hydrolysis.
Genetic differences between benign phyllodes tumors and fibroadenomas revealed through targeted next generation sequencing
(2021) Han, Aaron
Abstract: Breast fibroepithelial lesions are biphasic tumors which comprise the common benign fibroadenomas (FAs) and the rarer phyllodes tumors (PTs). This study analyzed 262 (42%) conventional FAs, 45 (7%) cellular FAs, and 321 (51%) benign PTs contributed by the International Fibroepithelial Consortium, using a previously curated 16 gene panel. Benign PTs were found to possess a higher number of mutations, and higher rates of cancer driver gene alterations than both groups of FAs, in particular MED12, TERT promoter, RARA, FLNA, SETD2, RB1, and EGFR. Cases with MED12 mutations were also more likely to have TERT promoter, RARA, SETD2, and EGFR. There were no significant differences detected between conventional FAs and cellular FAs, except for PIK3CA and MAP3K1. TERT promoter alterations were most optimal in discriminating between FAs and benign PTs. Our study affirms the role of sequencing and key mutations that may assist in refining diagnoses of these lesions.
Monocyte distribution width as a novel sepsis indicator in COVID-19 patients
(2022) Alsuwaidi, Laila; Al Heialy, Saba; Han, Aaron; Hachim, Mahmood Yaseen
Background: The severe acute respiratory syndrome coronavirus (SARS-CoV-2) is a highly transmittable virus which causes the novel coronavirus disease (COVID-19). Monocyte distribution width (MDW) is an in-vitro hematological parameter which describes the changes in monocyte size distribution and can indicate progression from localized infection to systemic infection. In this study we evaluated the correlation between the laboratory parameters and available clinical data in diferent quartiles of MDW to predict the progression and severity of COVID-19 infection. Methods: A retrospective analysis of clinical data collected in the Emergency Department of Rashid Hospital Trauma Center-DHA from adult individuals tested for SARS-CoV-2 between January and June 2020. The patients (n=2454) were assigned into quartiles based on their MDW value on admission. The four groups were analyzed to determine if MDW was an indicator to identify patients who are at increased risk for progression to sepsis. Results: Our data showed a signifcant positive correlation between MDW and various laboratory parameters associated with SARS-CoV-2 infection. The study also revealed that MDW≥24.685 has a strong correlation with poor prognosis of COVID-19. Conclusions: Monitoring of monocytes provides a window into the systemic infammation caused by infection and can aid in evaluating the progression and severity of COVID-19 infection.
Saliva as an Alternative Specimen for Molecular COVID-19 Testing in Community Settings and Population-Based Screening
(2020) Senok, Abiola; Alsuwaidi, Hanan; Han, Aaron; Al Heialy, Saba; Loney, Tom; Alsheikh-Ali, Alawi
Purpose: With the easing of restriction measures, repeated community-based sampling for tracking new COVID-19 infections is anticipated for the next 6 to 12 months. A non-invasive, self-collected specimen like saliva will be useful for such public health surveillance. Investigations on the use of saliva for SARS-CoV-2 RT-PCR have largely been among COVID-19 in-pa\tients and symptomatic ambulatory patients with limited work in a community-based screening setting. This study was carried out to address this paucity of data and reported discrepancies in diagnostic accuracy for saliva samples. Patients and Methods: From 29th June to 14th July 2020, adults presenting for COVID- 19 testing at a community-based screening facility in Dubai, United Arab Emirates were recruited. Clinical data, nasopharyngeal swab in universal transport media and drooling saliva in sterile containers were obtained. Reverse transcriptase PCR amplification of SARS-CoV-2 RdRp and N genes was used to detect the presence of the SARS-CoV-2 virus. Results: Of the 401 participants, 35 (8.7%) had viral detection in at least one specimen type and the majority (n=20/35; 57.1%) were asymptomatic. Both swab and saliva were positive in 19 (54.2%) patients, while 7 (20.0%) patients had swab positive/saliva negative results. There were 9 (25.7%) patients with saliva positive/swab negative result and this included 5 asymptomatic COVID-19 patients undergoing repeat screening. Using the swab as the reference gold standard, the sensitivity and specificity of saliva were 73.1% (95% CI 52.2–88.4%) and 97.6% (95% CI 95.5–98.9%) while the positive and negative predictive values were 67.9% (95% CI 51.5–80.8%) and 98.1% (95% CI 96.5–99.0%), respectively. Conclusion: The findings suggest good diagnostic accuracy for saliva and feasibility of utilization of specimen without transport media for SARS-CoV-2 RT-PCR. Saliva represents a potential specimen of choice in community settings and population-based screening.