Evaluación de antibiorresistencia de cepas de Shigella spp aisladas en carne de pollo en la ciudad de Ambato, provincia de Tungurahua

Abstract

Shigella spp exhibits remarkably high and highly developed antibiotic resistance mechanisms, which constitutes a global challenge for public health. One of the main routes of transmission of this resistance is observed in foods of animal origin, highlighting that the lack of hygiene and sanitary control in slaughter centers contributes to its spread. The objective of this research was to evaluate the antibioresistance of Shigella spp strains isolated from chicken meat in the city of Ambato, Tungurahua Province. We worked with 17 strains of Shigella spp subjected to two phases of research. In the first phase, the Kirby Bauer phenotypic method (diskplate) was used to determine the resistance, intermediate or susceptibility of the strains to a group of drugs that includes Azithromycin (AZM), Gentamicin (CN), Ceftriaxone (CRO), Amoxicillin + clavulanic acid (AMC) and Ciprofloxacin (CIP). The results were analyzed using the Kruskal Wallis test, complemented by the Mann Whitney U test. A resistance of 82.4% was obtained for CIP, 64.7% for AMC, 29.4% for CRO, 23.5% for CN and 5.9% for AZM. In the second phase, the Minimum Inhibitory Concentration (MIC) of the strains that showed sensitivity in phase 1 to the aforementioned antibiotics was determined. The results were analyzed descriptively using curves, establishing the MICs for AZM 160 μg/ml, CN 10 μg/ml, AMC 160 μg/ml, CRO 1.25 μg/ml and CIP 20 μg/ml, following the CLSI cut-off points in 2016. It was considered essential to investigate the resistance mechanisms exhibited by Shigella spp. First, we focused on fluoroquinolones, as this group showed significant resistance due to the presence of chromosomal mutations. In addition, resistance related to the production of ESBL was observed for beta-lactams, as well as the alteration of the target site present in aminoglycosides, the existence of genes such as mphA or ermB in macrolides. Keywords: Shigella spp, antibioresistance, MIC, mechanisms, antibiotics