Browsing by Author "Rivera, Sandra Patricia"
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Item Beta-Lactam-Resistant Enterobacterales Isolated from Landfill Leachates(2022-10) Mondragón Quiguanas, Alejandra; Villaquirán Muriel, Miguel Ángel; Rivera, Sandra Patricia; Rosero García, Doris; Aranaga, Carlos; Correa, Adriana; Falco, AuraAntibiotic resistance is one of the main challenges worldwide due to the high morbidity and mortality caused by infections produced by resistant bacteria. In Colombia, this problem has been studied mainly from the clinical perspective; however, it is scarcely studied in the leachates produced in landfills. The objective of this study was to detect, identify and determine the antibiotic sensitivity profile of Enterobacterales isolated from a leachate treatment plant located in Cali, Colombia. Detection was performed using selective culture media, bacterial identification using Matrix-Assisted Laser Desorption/Ionization-Time-Of-Flight (MALDI-TOF, bioMérieux) and by sequencing the gene coding for the 16S ribosomal RNA subunit when discrepancies were observed between phenotypic characteristics and MALDI-TOF. Antibiotic sensitivity profiling was determined using the automated VITEK®2 system (bioMérieux). Twenty-one isolates were obtained, of which Klebsiella pneumoniae was the most frequent (23.8%), and 34% of the isolates showed decreased sensitivity to beta-lactam antibiotics such as cefoxitin, ampicillin/sulbactam and piperacillin/tazobactam. These findings suggest that leachates from landfills could be a reservoir of pathogenic bacteria carrying antibiotic resistance determinants, so periodic microbiological characterization of these effluents should be performed, promoting the One Health approach.Item Identificación del Resistoma y viruloma de aislados clínicos de Pseudomonas aeruginosa multirresistente(Universidad Santiago de Cali, 2023) Méndez Banguera, Angelica María; Tarapues Mahecha, Angee Lorena; Rivera, Sandra Patricia; Ocampo Ibáñez, Iván DaríoPseudomonas aeruginosa is a microorganism of great clinical importance that has a physiology that gives it extensive resistance to antimicrobials, and that in recent years has acquired resistance and virulence mechanisms that make the treatment of infections difficult, reducing therapeutic options. The complex situation with this bacteria has increased interest in the search for alternatives to control the dissemination of multiresistant strains, emphasizing the study of its genome. The main objective of this research was the identification of the intrinsic and acquired antimicrobial resistance genes of three clinically isolated strains of multidrug-resistant P. aeruginosa, whose genomes were evaluated through a series of bioinformatic analyzes in order to determine the genes responsible for conferring resistance to beta-lactam type antibiotics. The annotation of the complete genome of the isolates was carried out followed by the alignment of the beta-lactamase genes found, in order to establish the relationship of the genes found through bioinformatics with those previously found in the laboratory during a previous study, as well as its relationship with other strains reported as multiresistant. Virulence factors related to the pathogenicity of multidrug-resistant Pseudomonas aeruginosa were also identified with the aim of understanding its behavior and importance in this type of microorganisms. Only genes categorized as antibiotic resistant were taken into account; the rest of the genes resistant to antimicrobials, including disinfectants and chemical bactericides, were discarded. 15 acquired resistance genes were found, of which 33.33% (5/15) correspond to beta-lactamase enzymes of different classes, 40% (6/15) to aminoglycoside resistance enzymes and, finally, 26.67% ( 4/15) of genes responsible for conferring resistance to fluoroquinolones. The comparison was performed according to the reference strain Pseudomonas aeruginosa PAO1. The most significant thing that was found during the classification was the presence of the resistance genes of the VIM family, responsible for encoding the class B beta-lactamase enzyme blaVIM-2 found both in the laboratory tests and in the annotation of the genome of the three isolated strains. Additionally, 26 intrinsic resistance genes were found where 7.69% (2/31) were beta-lactamase enzymes, while 30.77% (8/31) corresponded to efflux pump-forming complexes. The remaining 61.54% (16/26) was made up of other genes such as gyrA, gyrB, aph(3”)-llb, gibB, rpoC, PgsA, murA, fosA, folA, Arl, among others, distributed among the different families of antibiotics. Finally, in the virulence factors, mechanisms of action of adhesion, endotoxin (Waap), motility (fleN, FliD, fleQ, fliC, FlhB, fliP, fleR, flgL, pilX, pilU), biofilm (algA, algJ, algD) were identified. , algZ, algF, algU, algR), type II secretion system (LasA, LasB), type III secretion system (exoS, exoT, exoY) and protease (AprA), affirming what is described in the literature about P. aeruginosa, where it is classified as a multifactorial microorganism and whose mechanisms must be studied in depth since they are of utmost relevance for the health area.Item Síntesis de nanopartículas poliméricas asociadas a imipenem para enfrentar la multidrogorresistencia frente a la bacteria Klebsiella pneumoniae productora de carbapenemasas tipo KPC(Universidad Santiago de Cali, 2023) Bautista Rincón, Angibet; Chalarca Salazar, Angie Yuliet; Oñate Garzón, José Fernando; Rivera, Sandra PatriciaKlebsiella pneumoniae is a Gram negative bacterium and is the main Enterobacterium isolated in hospital infections, since it plays an important role in nosocomial diseases. Klebsiella pneumoniae is becoming a public health problem worldwide because it has a type of enzyme called KPC-type carbapenemase that gives the bacteria resistance to carbapenem drugs such as Imipenem, Meropenem, Ertapenem and Doripenem. Imipenem is an antibiotic that is supplied in combination with another drug called cilastatin, which helps to prolong the effect of imipenem by protecting it from breakdown when ingested [1], however, the administration of this type of drug generates side effects. in patients becoming nephrotoxic. One of the promising strategies to combat resistant bacteria, decrease the rate of morbidity and mortality from nosocomial infections, and reduce the side effects generated by the administration of certain antibiotics, is the use of antibiotic-loaded chitosan nanoparticles. Chitosan is a biopolymer that is obtained from the partial deacetylation of chitin which is present in the exoskeleton of crustaceans. Due to the high biocompatibility of chitosan, it is currently used as a material for the production of nanoparticles. Chitosan nanoparticles have high potential for the loading, transport and controlled release of molecules [2]. The purpose of this study is to develop polymeric chitosan nanoparticles associated with imipenem to face the bacterial resistance of Klebsiella pneumoniae. The method consists of the production and characterization of highly deacetylated chitosan and imipenem-loaded chitosan nanoparticles obtained by ionic gelation assisted by high intensity sonication. These nanoparticles were analyzed and characterized in terms of particle size, Polydispersity Index, Potential Zeta (PZ) and encapsulation efficiency. Its antimicrobial activity was evaluated using the broth microdilution method according to the Clinical & Laboratory Standards Institute (CLSI) using carbapenem-sensitive and resistant Klebsiella pneumoniae strains. As a result, a particle size < 500 nm, positive Zeta potential values and a stable polydispersity index with values between 0.07 and 0.2 were obtained, obtaining a monodisperse population. The reported results were promising for Klebsiella pneumoniae demonstrating that imipenem-loaded chitosan nanosystems provided antibacterial efficacy compared to free imipenem against Gram-negative bacteria resistant to this antibiotic