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result(s) for
"Alex, Vinitha"
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Imported Cholera Cases, South Africa, 2023
by
Lee, Christine C.
,
Erasmus, Linda K.
,
Njamkepo, Elisabeth
in
Asia, Southern
,
bacteria
,
Causes of
2023
Since February 2022, Malawi has experienced a cholera outbreak of >54,000 cases. We investigated 6 cases in South Africa and found that isolates linked to the outbreak were Vibrio cholerae O1 serotype Ogawa from seventh pandemic El Tor sublineage AFR15, indicating a new introduction of cholera into Africa from south Asia.
Journal Article
A retrospective analysis of community-onset bloodstream infections at a tertiary-care academic hospital in South Africa. Are current empiric antimicrobial practices appropriate?
by
Alex, Vinitha
,
Chibabhai, Vindana
,
Nana, Trusha
in
Age groups
,
Antibiotics
,
Antimicrobial agents
2021
Background:Community-onset bloodstream infection (CO-BSI) is associated with substantial morbidity and mortality. Knowledge of locally prevalent pathogens and antimicrobial susceptibility patterns can promptly guide appropriate empiric therapy and improve outcomes.Objectives:We sought to determine the epidemiology of CO-BSI, the blood culture positivity rate and the contamination rate. We also sought to establish appropriateness of current empiric antimicrobial therapy practices.Methods:We retrospectively analyzed blood cultures taken from January 2015 to December 2019 at the emergency departments (EDs) of a tertiary-care academic hospital in South Africa using extracted laboratory data.Results:The overall positivity rate of blood cultures taken at the EDs was 15% (95% confidence interval [CI], 0.15–0.16) and the contamination rate was 7% (95% CI, 0.06–0.07). Gram-positive bacteria predominated in the pediatric cohort: neonates, 52 (54%) of 96; infants, 57 (52%) of 109; older children, 63 (61%) of 103. Methicillin-susceptible Staphylococcus aureus was the predominant pathogen among older children: 30 (35%) of 85. Escherichia coli was the most common pathogen isolated among adults and the elderly: 225 (21%) of 1,060 and 62 (29%) of 214, respectively. Among neonates, the susceptibility of E. coli and Klebsiella pneumoniae to the combination of ampicillin and gentamicin was 17 (68%) of 25. Among adults, the susceptibility of the 5 most common pathogens to amoxicillin-clavulanate was 426 (78%) of 546 and their susceptibility to ceftriaxone was 481 (85%) of 565 (P = .20). The prevalence of methicillin-resistant S. aureus, extended-spectrum β-lactamase–producing and carbapenem-resistant Enterobacterales were low among all age groups.Conclusions:Review of blood culture collection techniques is warranted to reduce the contamination rate. High rates of resistance to currently prescribed empiric antimicrobial agents for CO-BSI warrants a re-evaluation of local guidelines.
Journal Article
Microbe Mail: A microbiology and infectious diseases podcast for clinicians and students
by
Marais, Gert JK
,
Vinitha Alex
,
Chibabhai, Vindana
in
Costs
,
Digital broadcasting
,
Disease control
2023
Microbe Mail medical podcast is an audio-only informal educational platform, which addresses widespread topics in medical microbiology and infectious diseases (ID), with a particular focus on low- and middle-income settings. Podcasting has become a common form of informal learning in healthcare education and for continual professional development (CPD).Contribution: In this article, we discuss the development of the Microbe Mail podcast, its informal microbiology and ID education impact in the 2 years since commencement and future directions to improve uptake in Africa and low- and middle-income countries.
Journal Article
Electrocorticography reveals the temporal dynamics of posterior parietal cortical activity during recognition memory decisions
by
Chen, Janice
,
Rangarajan, Vinitha
,
Uncapher, Melina R.
in
Biological Sciences
,
Decision analysis
,
Electrocorticography
2015
Theories of the neurobiology of episodic memory predominantly focus on the contributions of medial temporal lobe structures, based on extensive lesion, electrophysiological, and imaging evidence. Against this backdrop, functional neuroimaging data have unexpectedly implicated left posterior parietal cortex (PPC) in episodic retrieval, revealing distinct activation patterns in PPC subregions as humans make memory-related decisions. To date, theorizing about the functional contributions of PPC has been hampered by the absence of information about the temporal dynamics of PPC activity as retrieval unfolds. Here, we leveraged electrocorticography to examine the temporal profile of high gamma power (HGP) in dorsal PPC subregions as participants made old/new recognition memory decisions. A double dissociation in memory-related HGP was observed, with activity in left intraparietal sulcus (IPS) and left superior parietal lobule (SPL) differing in time and sign for recognized old items (Hits) and correctly rejected novel items (CRs). Specifically, HGP in left IPS increased for Hits 300–700 ms poststimulus onset, and decayed to baseline ∼200 ms preresponse. By contrast, HGP in left SPL increased for CRs early after stimulus onset (200−300 ms) and late in the memory decision (from 700 ms to response). These memory-related effects were unique to left PPC, as they were not observed in right PPC. Finally, memory-related HGP in left IPS and SPL was sufficiently reliable to enable brain-based decoding of the participant’s memory state at the single-trial level, using multivariate pattern classification. Collectively, these data provide insights into left PPC temporal dynamics as humans make recognition memory decisions.
Journal Article
Complexity of spin configurations dynamics due to unitary evolution and periodic projective measurements
by
Rodriguez, Alex
,
Casagrande, Heitor P
,
Xing, Bo
in
Cellular automata
,
Complexity
,
Figure of merit
2023
We study the Hamiltonian dynamics of a many-body quantum system subjected to periodic projective measurements which leads to probabilistic cellular automata dynamics. Given a sequence of measured values, we characterize their dynamics by performing a principal component analysis. The number of principal components required for an almost complete description of the system, which is a measure of complexity we refer to as PCA complexity, is studied as a function of the Hamiltonian parameters and measurement intervals. We consider different Hamiltonians that describe interacting, non-interacting, integrable, and non-integrable systems, including random local Hamiltonians and translational invariant random local Hamiltonians. In all these scenarios, we find that the PCA complexity grows rapidly in time before approaching a plateau. The dynamics of the PCA complexity can vary quantitatively and qualitatively as a function of the Hamiltonian parameters and measurement protocol. Importantly, the dynamics of PCA complexity present behavior that is considerably less sensitive to the specific system parameters for models which lack simple local dynamics, as is often the case in non-integrable models. In particular, we point out a figure of merit that considers the local dynamics and the measurement direction to predict the sensitivity of the PCA complexity dynamics to the system parameters.