Karen Loaiza

Ms. Karen Loaiza

Bacteria, Parasites, and Fungi, Statens Serum Institut, Copenhagen, Hovedstaden, Denmark
orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

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

Representative Publications

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1 September 2019 in Journal of Global Antimicrobial Resistance
Verified
Journal Article
Open access
DODavid Ortega-Paredes
David Ortega-Paredes
MHMarco Haro
Marco Haro
PLPaula Leoro-Garzón
Paula Leoro-Garzón
PBPedro Barba
Pedro Barba
KLKaren Loaiza
Karen Loaiza
EFEsteban Fernández-Moreira
Esteban Fernández-Moreira
This study focused on estimating the prevalence of extended-spectrum β-lactamases (ESBLs), plasmid-mediated AmpC β-lactamases, carbapenemases and MCR-1-producing Escherichia coli in canine faeces from a public park in Quito, Ecuador. Phenotypic and genotypic characterisation of E. coli isolated from 50 canine faecal samples recovered from a city park in Quito was performed. In addition, a multiple choice survey was conducted among 50 dog owners. Of the 50 faecal samples, 20 (40.0%) presented E. coli resistant to ceftriaxone. Moreover, 23 E. coli isolates were recovered for further analysis. All of the isolates showed as multidrug-resistant (MDR) phenotype (resistant to three or more antibiotic families). Resistance to carbapenems, tigecycline and amikacin was not observed. No major clonal relatedness was observed among the resistant isolates. The ESBL genes blaCTX-M-15, blaCTX-M-55 and blaCTX-M-65 were the most common. Two isolates harboured the blaCMY-2 gene and one isolate harboured both mcr-1 and blaCTX-M-65. Statistical analysis showed that older people were more conscious of collecting and disposing of dog faeces than subjects aged <35 years (P < 0.05). The finding of MDR E. coli in dog faeces in a city park in Ecuador illustrates the importance of analysing canine faeces in public settings (e.g. parks, playgrounds) as part of surveillance programmes for MDR E. coli. In addition, this research might be a sentinel sampling method to gain a better understanding of community sources of antibiotic-resistant Enterobacteriaceae at human-animal-environment interfaces.

1 July 2021 in International Journal of Infectious Diseases
Verified
Journal Article
Open access
GSGabriela Sevillano
Gabriela Sevillano
DODavid Ortega-Paredes
David Ortega-Paredes
KLKaren Loaiza
Karen Loaiza
CZCamilo Zurita-Salinas
Camilo Zurita-Salinas
JZJeannete Zurita
Jeannete Zurita
To date, reported SARS-CoV-2 reinfection cases are mainly from strains belonging to different clades. As the pandemic advances, a few lineages have become dominant in certain areas leading to reinfections by similar strains. Here, we report a reinfection case within the same clade of the initial infection in a symptomatic 28-year-old-male in Quito-Ecuador. Infection was detected by reverse transcription-polymerase chain reaction, and immune response evaluated by antibody testing. Whole-genome sequencing was performed and phylogenetic analysis conducted to determine relatedness. Both the infection and the reinfection strains were assigned as Nextstrain 20B, Pangolin lineage B.1.1 and GISAID clade O. Our analysis indicated 4–6 fold more nucleotide changes than are expected for reactivation or persistence compared with the natural rate of SARS-CoV-2 mutation (∼2–3 nucleotide changes per month), thus supporting reinfection. Furthermore, approximately 3 months after the second infection, COVID-19 antibodies were not detectable in the patient, suggesting potential vulnerability to a third infection. Our results showed evidence of SARS-CoV-2 reinfection within the same clade in Ecuador, indicating that previous exposure to SARS-CoV-2 does not guarantee immunity in all cases.

25 April 2024 in Antibiotics
Verified
Journal Article
Open access
PDF file
MZMaría Nicole Solis Zumba
María Nicole Solis Zumba
KLKaren Loaiza
Karen Loaiza
LTLilibeth Torres
Lilibeth Torres
IMIvan Mina
Ivan Mina
Miroslava ŠefcováMiroslava Šefcová
Miroslava Šefcová
MLMarco Larrea-Álvarez
Marco Larrea-Álvarez
Various genetic elements, including integrons, are known to contribute to the development of antimicrobial resistance. Class 1 integrons have been identified in E. coli isolates and are associated with multidrug resistance in countries of the Andean Community. However, detailed information on the gene cassettes located on the variable regions of integrons is lacking. Here, we investigated the presence and diversity of class 1 integrons, using an in silico approach, in 2533 whole-genome sequences obtained from EnteroBase. IntFinder v1.0 revealed that almost one-third of isolates contained these platforms. Integron-bearing isolates were associated with environmental, food, human, and animal origins reported from all countries under scrutiny. Moreover, they were identified in clones known for their pathogenicity or multidrug resistance. Integrons carried cassettes associated with aminoglycoside (aadA), trimethoprim (dfrA), cephalosporin (blaOXA; blaDHA), and fluoroquinolone (aac(6′)-Ib-cr; qnrB) resistance. These platforms showed higher diversity and larger numbers than previously reported. Moreover, integrons carrying more than three cassettes in their variable regions were determined. Monitoring the prevalence and diversity of genetic elements is necessary for recognizing emergent patterns of resistance in pathogenic bacteria, especially in countries where various factors are recognized to favor the selection of resistant microorganisms.

12 November 2021 in Antibiotics
Verified
Journal Article
Open access
PDF file
LTLilibeth Torres
Lilibeth Torres
DODavid Ortega-Paredes
David Ortega-Paredes
KLKaren Loaiza
Karen Loaiza
EFEsteban Fernandez-Moreira
Esteban Fernandez-Moreira
MLMarco Larrea-Álvarez
Marco Larrea-Álvarez
Antimicrobial resistance genes are often associated with integrons, which promote their movement between and within DNA molecules. IntFinder 1.0 and I-VIP v1.2 were used for the detection of integrons and their associated resistance genes in assembled sequences and raw reads. A dataset comprising 1688 sequenced Salmonella enterica isolates from countries of the Andean Community was developed. A total of 749 and 680 integrons were identified by IntFinder 1.0 and I-VIP v1.2, respectively; class 2 integrons were the most abundant followed by class 1, whereas no class 3 integrons were detected. These elements were mainly associated with isolates from animal sources. S. Infantis ST32 contained the majority of integrons. Trimethoprim resistance genes (dfrA) were found in greater numbers than others, including aadA and bla genes. The presence of these resistance integrons may come as a response to antibiotic misuse, especially of co-trimoxazole. This represents a public health risk as novel resistant strains might appear due to gene dissemination. The information gathered from in silico studies not only contributes to our understanding of integron dynamics in pathogenic Salmonella, but also helps identify potential emergent patterns of resistance in the region, which is fundamental for developing pertinent antibiotic surveillance programs.

DODavid Ortega-Paredes
David Ortega-Paredes
CLCésar Larrea-Álvarez
César Larrea-Álvarez
SJSantiago Jijón
Santiago Jijón
KLKaren Loaiza
Karen Loaiza
Miroslava ŠefcováMiroslava Šefcová
Miroslava Šefcová
MLMarco Larrea-Álvarez
Marco Larrea-Álvarez
Adherence to preventive measures is influenced by people’s knowledge, attitudes and practices towards a disease; therefore, assessing knowledge of COVID-19 is critical in the overall effort to contain the outbreak. This cross-sectional study was conducted among undergraduates (n = 3621) of different programs and different levels of education associated with universities in north-central Ecuador. The form consisted of 32 questions covering demographics, symptoms, detection, treatment, transmission, prevention and knowledge of the virus. The rate of correct answers was 75.5% (21.1 ± 5 out of 28), with differences observed regarding program of study, educational level and location of institution (α = 0.05), although effect size analyses showed that these differences could not be considered large. Multiple linear regression analyses showed that lower scores were associated with initial stages of education, careers related to social sciences and location of institution. Participants possessed sufficient knowledge about detection, transmission and prevention, although they overestimated fatality rate and were less confident about the characteristics of the virus and the effectiveness of traditional medicine. Consequently, future educational programs must place emphasis on addressing deficient knowledge. Certainly, improving COVID-19 literacy will promote the appropriate application of protective measures aimed at preventing the virus’ spread.

DODavid Ortega-Paredes
David Ortega-Paredes
JZJeannete Zurita
Jeannete Zurita
CZCamilo Sebastian Zurita
Camilo Sebastian Zurita
PLPaula Leoro-Garzon
Paula Leoro-Garzon
GLGalo Leoro-Monroy
Galo Leoro-Monroy
MLMarco Larrea-Álvarez
Marco Larrea-Álvarez
Several public health measures have been implemented to contain the SARS-CoV-2 outbreak. The adherence to control measures is known to be influenced by people’s knowledge, attitudes and practices with regard to the disease. This study aimed at assessing COVID-19 knowledge in individuals who were tested for the virus. An online cross-sectional survey of 32 items, adapted to the national context, was conducted among 1656 Ecuadorians. The mean knowledge score was 22.5 ± 3 out of 28, with significant differences being observed with regard to educational attainment. People with postgraduate training scored higher than those with college, secondary and elementary instruction. Indeed, multiple linear regression revealed that lower scores were associated significantly with the latter three levels of education. Interviewees were knowledgeable about the symptoms, detection, transmission and prevention of the disease. However, they were less assertive regarding the characteristics of the virus as well as the usefulness of traditional and unproven treatments. These outcomes indicated a lack of knowledge in fundamental aspects of virus biology, which may limit the effectiveness of further prevention campaigns. Conclusively, educational and communicational programs must place emphasis on explaining the basic molecular characteristics of SARS-CoV-2; such information will certainly contribute to improve the public’s adherence to control measures.