Barbara Ymaña

Ms. Barbara Ymaña

orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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11 September 2020 in Microorganisms
Verified
Journal Article
Open access
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MPMaria J. Pons
Maria J. Pons
MMMarta Marí-Almirall
Marta Marí-Almirall
BYBarbara Ymaña
Barbara Ymaña
JMJeel Moya-Salazar
Jeel Moya-Salazar
LMLaura Muñoz
Laura Muñoz
Ignasi RocaIgnasi Roca
Ignasi Roca
The aim of this study was to characterize carbapenem-resistant Klebsiella pneumoniae (CR-Kp) isolates recovered from adults and children with severe bacteremia in a Peruvian Hospital in June 2018. Antimicrobial susceptibility was determined by disc/gradient diffusion and broth microdilution when necessary. Antibiotic resistance mechanisms were evaluated by PCR and DNA sequencing. Clonal relatedness was assessed using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Plasmid typing was performed with a PCR-based method. Thirty CR-Kp isolates were recovered in June 2018. All isolates were non-susceptible to all β-lactams, ciprofloxacin, gentamicin and trimethoprim-sulfamethoxazole, while mostly remaining susceptible to colistin, tigecycline, levofloxacin and amikacin. All isolates carried the blaNDM-1 gene and were extended spectrum β-lactamase (ESBL) producers. PFGE showed four different pulsotypes although all isolates but two belonged to the ST348 sequence type, previously reported in Portugal. blaNDM-1 was located in an IncFIB-M conjugative plasmid. To our knowledge, this is the first report of an New Delhi metallo-β-lactamase (NDM)-producing K. pneumoniae recovered from both children and adults in Lima, Peru, as well as the first time that the outbreak strain ST348 is reported in Peru and is associated with NDM. Studies providing epidemiological and molecular data on CR-Kp in Peru are essential to monitor their dissemination and prevent further spread.

2 January 2021 in Pathogens and Global Health
Verified
Journal Article
Closed access
JMJasmine Morante
Jasmine Morante
AQAntonio M. Quispe
Antonio M. Quispe
BYBarbara Ymaña
Barbara Ymaña
JMJeel Moya-Salazar
Jeel Moya-Salazar
NLNéstor Luque
Néstor Luque
MPMaria J. Pons
Maria J. Pons
Disinfectants play an essential role in controlling the dissemination of bacteria in health care settings, but it may also contribute to the selection of antibiotic resistance bacteria. This study looked at Klebsiella pneumoniae isolates collected from three hospitals in Lima, Peru, in order to evaluate: their susceptibility to chlorhexidine [CHG] and isopropanol [ISP]), and their association with antimicrobial susceptibility. We analyzed 59 K. pneumoniae isolates and assessed their CHG and ISP susceptibility by minimum inhibitory concentrations (MICs). Additionally, we performed a regression analysis to assess the association between disinfectant tolerance and antibiotic resistance (measured by the disc diffusion method), colistin resistance (by microdilution), carbapenemases presence (by polymerase chain reaction [PCR]), and clonal relationships (by pulsed-field gel electrophoresis [PFGE]). Eleven K. pneumoniae strains were isolated from fomites, and 48 strains from clinical samples. The MIC range of these isolates was 8–128 µg/ml for CHG and 16–256 mg/ml for ISP. We found that resistance to trimethoprim/sulfamethoxazole (TMP/SMX) was the main factor associated with CHG log2 MIC (ß = 0.65; 95%CI: 0.03, 1.27; R2 = 0.07). In the case of ISP, the log2(MIC) was associated with the institution of origin, showing lower ISP log2(MIC) in fomites compared to clinical samples(ß = −0.77; 95%CI: −1.54, −0.01; R2 = 0.08). Resistance to CHG and ISP among K. pneumoniae isolates found in Peruvian hospitals seems to be elevated and highly variable. Further studies are needed to confirm our results and implement actionable interventions if necessary.

5 January 2022 in Transactions of the Royal Society of Tropical Medicine and Hygiene
Verified
Journal Article
Closed access
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BYBarbara Ymaña
Barbara Ymaña
NLNestor Luque
Nestor Luque
JRJoaquim Ruiz
Joaquim Ruiz
MPMaria J. Pons
Maria J. Pons
Healthcare worker (HCW) uniforms and cell phones are involved in pathogen transmission. This study aimed to characterize pathogenic microorganism isolates from HCW uniforms and cell phones. Gram-negative microorganisms were recovered from HCW uniforms and cell phones. Antimicrobial susceptibility and the presence of extended-spectrum β-lactamases (ESBL) and carbapenemases were determined. Escherichia coli was the most prevalent microorganism. Overall, high levels of resistance to cephalosporins, quinolones, co-trimoxazole and colistin were found. ESBL were mainly related to blaCTX-M-15 and blaSHV- genes. Carbapenem-resistant isolates presented as blaKPC or blaNDM. High levels of antimicrobial resistance, including colistin, were detected. Therefore, strategies are urgently needed to prevent bacterial dissemination.

21 August 2020 in Revista Peruana de Medicina Experimental Y Salud Pública
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Journal Article
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ANAndrea Naomi-Matsuoka
Andrea Naomi-Matsuoka
MVMarina Vargas
Marina Vargas
BYBarbara Ymaña
Barbara Ymaña
GSGabriela Soza
Gabriela Soza
MPMaria J. Pons
Maria J. Pons
El objetivo del estudio fue evaluar los niveles y mecanismos de resistencia a la colistina y a los carbapenémicos en cepas de Klebsiella pneumoniae multidrogorresistente aisladas durante el periodo 2015-2018 en el Instituto Materno Perinatal de Lima. Se analizó la sensibilidad mediante difusión en disco y microdilución. La presencia de genes de resistencia a los carbapenémicos y a la colistina se determinó por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés) y se la relacionó con la clonalidad. Se analizaron 36 cepas de K. pneumoniae, cinco (13,8%) fueron resistentes a la colistina, pertenecían a diferentes grupos clonales. Se encontraron dos cepas con carbapenemasas (blaKPC y blaNDM) y no se detectaron genes plasmídicos para la colistina. Los niveles de resistencia al resto de antimicrobianos testados fueron elevados, a excepción de amikacina (13,9%). Los resultados destacan la presencia de cepas resistentes a la colistina (33,3% en 2018), situación preocupante por ser esta parte de las últimas alternativas de tratamiento para las infecciones causadas por patógenos multirresistentes

7 June 2023 in The American Journal of Tropical Medicine and Hygiene
Verified
Journal Article
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MPMaria J. Pons
Maria J. Pons
AMAna Mayanga-Herrera
Ana Mayanga-Herrera
GUGabriela M. Ulloa
Gabriela M. Ulloa
BYBarbara Ymaña
Barbara Ymaña
SMSabrina Medina
Sabrina Medina
AQAntonio M. Quispe
Antonio M. Quispe
: The COVID-19 pandemic affected the main Amazon cities dramatically, with Iquitos City reporting the highest seroprevalence of anti-SARS-CoV-2 antibodies during the first COVID-19 wave worldwide. This phenomenon raised many questions about the possibility of a co-circulation of dengue and COVID-19 and its consequences. We carried out a population-based cohort study in Iquitos, Peru. We obtained a venous blood sample from a subset of 326 adults from the Iquitos COVID-19 cohort (August 13–18, 2020) to estimate the seroprevalence of anti-dengue virus (DENV) and anti-SARS-CoV-2 antibodies. We tested each serum sample for anti-DENV IgG (serotypes 1, 2, 3, and 4) and SARS-CoV-2 antibodies anti-spike IgG and IgM by ELISA. We estimated an anti-SARS-CoV-2 seroprevalence of 78.0% (95% CI, 73.0–82.0) and an anti-DENV seroprevalence of 88.0% (95% CI, 84.0–91.6), signifying a high seroprevalence of both diseases during the first wave of COVID-19 transmission in the city. The San Juan District had a lower anti-DENV antibody seroprevalence than the Belen District (prevalence ratio, 0.90; 95% CI, 0.82–0.98). However, we did not observe these differences in anti-SARS-CoV-2 antibody seroprevalence. Iquitos City presented one of the highest seroprevalence rates of anti-DENV and anti-SARS-CoV-2 antibodies worldwide, but with no correlation between their antibody levels.

30 December 2024 in South Health
Verified
Journal Article
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JRJoaquim Ruiz
Joaquim Ruiz
RERocio Egoavil Espejo
Rocio Egoavil Espejo
BYBarbara Ymaña
Barbara Ymaña
RORosario Oporto-Llerena
Rosario Oporto-Llerena
MPMaria J. Pons
Maria J. Pons
Cefiderocol is a new antibacterial agent active against Gram-negative bacteria of clinical interest. Cefiderocol passively penetrates the bacteria through porins and actively through iron uptake systems. This peculiarity results in the need to perform slight modifications when performing minimal inhibitory concentration assays. Thus, it is needed a cation-free culture media, and a thin grown is unconsidered.