Laboratorio Clínico

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ACTIVIDAD ANTIMICROBIANA Y ANTIBIOFILM DEL ACEITE ESENCIAL DE CYMBOPOGON CITRATUS EN STAPHYLOCOCCUS AUREUS.
(2026-01-30) Acurio Diaz Jefferson Alejandro; Proaño Pérez, María Elizabeth; Universidad Técnica de Ambato / Facultad de Ciencias de Salud / Carrera de Laboratorio Clínico
Staphylococcus aureus is a highly relevant human pathogen responsible for chronic and recurrent infections. Its methicillin-resistant variant, methicillin-resistant Staphylococcus aureus (MRSA), is considered by the World Health Organization as a high-priority pathogen. In addition, both S. aureus and MRSA have the ability to form biofilms (1–3). Given this problem, the essential oil of Lemongrass (Cymbopogon citratus) was used due to its chemical composition. Microencapsulation was employed to prevent the essential oil from losing its physicochemical properties (4,5). The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC), as well as their relationship, were determined using the MTT viability assay. In S. aureus ATCC 25923, the MIC was 3.12 mg/mL and the MBC was 6.25 mg/mL. In MRSA ATCC 43300, the MIC was 6.25 mg/mL and the MBC was 50 mg/mL (5,6). The antibiofilm activity of the pure and microencapsulated essential oil was assessed using crystal violet to quantify the biomass of the strains. The pure oil showed excellent antibiofilm activity with no variations in inhibition; however, with microencapsulated oil, S. aureus ATCC 25923 showed 16.27% inhibition at 0.39 mg/mL. In MRSA ATCC 43300, inhibition reached 45.25% at 0.39 mg/mL. RT-qPCR was performed to identify the expression of the icaA gene. At concentrations of 0.39 mg/mL, amplification was observed in S. aureus ATCC 25923 and MRSA ATCC 43300 at cycle thresholds of 22.35 and 24.89, respectively (7,8). In conclusion, the essential oil of Cymbopogon citratus exhibits antimicrobial and antibiofilm activity against S. aureus.
EVALUACIÓN ANTIFÚNGICA Y ANTI BIOFILM DE ACEITES ESENCIALES EN CANDIDA ALBICANS ATCC 10231
(2026-07-02) Acosta Acosta, Lissette Estefania; Proaño Pérez, María Elizabeth; Universidad Técnica de Ambato / Facultad de Ciencias de Salud / Carrera de Laboratorio Clínico
Candida albicans is considered by the World Health Organization (WHO) to be a critical priority pathogen, associated with high rates of in-hospital mortality, especially in immunocompromised patients. Its ability to form biofilms increases resistance to conventional antifungals by 100 to 1000 times, and the expression of genes such as HWP1 and SAP3 facilitate the adhesion, degradation, and maturation of these structures, severely limiting available therapeutic options. The objective was to evaluate the antifungal and antibiofilm activity of cinnamon and lemon verbena essential oils against Candida albicans ATCC 10231. A quantitative and experimental approach was used, employing well diffusion, MIC, MFC, crystal violet staining, and RT-PCR. Cinnamon showed an MIC of 1.56 mg/mL and lemon verbena of 3.12 mg/mL. The strain exhibited weak biofilm formation (OD=0.585). Lemon verbena inhibited up to 99.87% of the biofilm, and cinnamon reached 92.81%. Both oils completely suppressed HWP1 gene expression at 50 mg/mL. It is concluded that the evaluated essential oils possess antifungal and antibiofilm potential, constituting a natural alternative against Candida albicans infections.
EVALUACIÓN ANTIMICROBIANA IN VITRO DEL ACEITE ESENCIAL Y MICROENCAPSULADO ROSMARINUS OFFICINALIS FRENTE A BACTERIAS ATCC
(2025-02-25) Macías García, Emily Masielle; Guangasig Toapanta, Víctor Hernán; Universidad Técnica de Ambato/ Facultad de Ciencias de Salud /Carrera de Laboratorio Clínico
Bacterial resistance to antibiotics represents a global crisis recognized by organizations such as the WHO, UN, and EU, causing millions of deaths each year (1). In response to this challenge, the search for innovative alternatives to treat resistant infections has become crucial to ensure the effectiveness of treatments. This study focuses on the evaluation of the antimicrobial activity of essential oil (EO) and its microencapsulated form (AEM) derived from Rosmarinus officinalis. Microencapsulation, carried out through spray drying, enhances the stability of the oil, optimizes its efficacy, and enables controlled release, overcoming limitations such as its volatility and reduced effectiveness in its pure form. The antimicrobial properties of EO and AEM were analyzed against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853. AEM demonstrated exceptional performance, with inhibition zones of up to 21.6 mm against S. aureus. Furthermore, minimum inhibitory concentrations (MIC) of 12.5 mg/mL and minimum bactericidal concentrations (MBC) of 25 mg/mL were determined for S. aureus. For E. coli and P. aeruginosa, the MIC values were 25 mg/mL and 50 mg/mL, respectively. These results position AEM as a promising alternative in the healthcare field, standing out for its innovation, effectiveness, and relevance in the context of the growing antimicrobial resistance.
EVALUACIÓN ANTIMICROBIANA Y ANTI BIOFILM DE ACEITES ESENCIALES EN KLEBSIELLA SP
(2026-07-01) Morales Maliza, Karen Natasha; Proaño Pérez, María Elizabeth; Universidad Técnica de Ambato / Facultad de Ciencias de Salud / Carrera de Laboratorio Clínico
Antimicrobial resistance (AMR) is one of the main threats to public health, especially in bacteria such as K. pneumoniae, due to its high capacity to develop resistance mechanisms and form biofilms, which hinders the treatment of associated infections. Given this problem, the present research, as its general objective, evaluated the antimicrobial and antibiofilm activity of the essential oils of E. globulus (eucalyptus) and R. officinalis (rosemary) against K. pneumoniae strains BAA-1705 and BAA- 1706. The research had a quantitative and experimental approach, employing microbiological and molecular techniques, including modified Kirby-Bauer, resazurin assay to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC), crystal violet staining for biofilm quantification, and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) for mrkA gene expression. Applying the aforementioned methodology, it was found that eucalyptus oil exhibited an MIC of 25 mg/mL and MBC of 50 mg/mL against strains BAA-1705 and BAA- 1706, while rosemary showed an MIC of 12.5 mg/mL and MBC of 25 mg/mL against BAA-1705, and an MIC of 25 mg/mL and MBC of 50 mg/mL against BAA-1706. Furthermore, in terms of antibiofilm activity, rosemary demonstrated greater efficacy, achieving 78.13% inhibition in BAA-1705 and no amplification of the mrkA gene at 50 mg/mL in both strains. In conclusion, R. officinalis essential oil exhibits antimicrobial and antibiofilm activity against K. pneumoniae.