Association of phylogenetic distribution and presence of integrons with multidrug resistance in Escherichia coli clinical isolates from children with diarrhoea.

BACKGROUND: Escherichia coli strains include both commensal and virulent clones distributed in different phylogenetic groups. Antimicrobial resistance is an increasingly serious public health threat at the global level and integrons are important mobile genetic elements involved in resistance dissemination. This paper aims to determine the phylogenetic groups and presence of class 1 (intl1) and 2 (intl2) integrons in E. coli clinical isolates from children with diarrhoea, and to associate these characteristics with their antimicrobial resistance. METHODS: Phylogeny and presence of integrons (intl1 and intl2) were analysed by PCR and amplicon sequencing in 70 E. coli isolates from children with and without diarrhoea (35 of each group) from Sinaloa, Mexico; these variables were analysed for correlation with the antimicrobial resistance profile of the isolates. RESULTS: The most frequent phylogroups were A (42.9%) and B2 (15.7%). The E. coli isolates from children with diarrhoea were distributed in all phylogroups; while strains from children without diarrhoea were absent from phylogroups C, E, and clade I. The 17.1% of the isolates carried integrons (15.7% intI1 and 1.4% intI2); 28.6% of the isolates from children with diarrhoea showed the class 1 integron. Strains of phylogroup A showed the highest frequency of integrons (33.3%). The association of multidrug resistance and the presence of integrons was identified in 58.3% of strains isolated from children with diarrhoea included in phylogroups A and B2. The sequence analysis of intl1 and intl2 showed silent point mutations and similarities with plasmids of some APEC and AIEC strains. CONCLUSION: Commensal E. coli strains are potential disseminators of antimicrobial resistance, and the improvement in the use of antimicrobials to treat childhood diarrhoea is essential for the control of such resistance.

High prevalence of multidrug-resistant Escherichia coli isolates from children with and without diarrhoea and their susceptibility to the antibacterial activity of extracts/fractions of fruits native to Mexico.

PURPOSE: This paper aims to evaluate the antimicrobial resistance of Esherichia coli isolates from children under 5 years old, with and without diarrhoea, who were hospital outpatients in Culiacan, Sinaloa, Mexico. It also looks at the antimicrobial activity of fruit extracts against selected multidrug-resistant (MDR) E. coli strains. METHODOLOGY: A total of 205 E. coli isolates from stool samples were collected from 94 children under 5 years old who were outpatients from two hospitals in the city of Culiacan, Sinaloa, Mexico, during the autumn/winter of 2003/04; their resistance profiles to 19 commercial antimicrobials were investigated using the Kirby-Bauer method. The antibacterial activities of extracts/fractions of fruits (i.e. uvalama, Vitex mollis; ayale, Crescentia alata; and arrayan, Psidium sartorianum) were evaluated using the broth microdilution method. RESULTS: All E. coli isolates were susceptible to amikacin, nitrofurantoin and meropenem, and approximately 96 % were resistant to at least one antimicrobial, especially carbenicillin (93.2 %), cefuroxime sodium (53.7 %), ampicillin (40 %) and trimethoprim/sulfamethoxazole (35.1 %). Likewise, the frequency of MDR strains (44.9 %) was high, and no significant association with diarrhoea symptoms was found. Remarkably, all fruit extracts/fractions showed antibacterial activity against some, but not all, MDR isolates. The lowest minimal inhibitory concentration values were for the hexane fraction of arrayan (0.25 mg ml-1). CONCLUSION: A high number of antimicrobial-resistant E. coli (especially to ß-lactams and sulfonamides) and MDR isolates were detected in children under 5 years old, irrespective of diarrhoea symptoms; this is novel information for Culiacan, Sinaloa, Mexico. Moreover, our results showed that the studied fruit extracts/fractions are potential alternative or complementary treatments for MDR E. coli strains.

Actividad antibacteriana de extractos de frutos de nanchi (Byrsonima crassifolia (L.) Kunth), arrayán (Psidium sartorianum (O. Berg) Nied.) y ayale (Crescentia alata Kunth) / Antibacterial activity of extracts obtained from the nanchi (Byrsonima crassifolia (L.) Kunth), arrayan (Psidium sartorianum (O. Berg) Nied.) and ayale (Crescentia alata Kunth) fruits

Nanchi (Byrsonima crassifolia), arrayan (Psidium sartorianum) and ayale (Crescentia alata) are wild and under-utilized plants from Mexico; their fruits have been used as food and as Mexican traditional remedies against human bacterial infections (e.g. bacillary dysentery). However, scientific reports which support such uses or promote their consumption are scarce. In this work, the antibacterial activities of fruit extracts (i.e. hexanic, HE; chloroformic, CE; and methanolic, ME) were determined by the micro-dilution assay, establishing the Minimum Inhibitory Concentration (MIC) and Minimum Bactericide Concentration (MBC) against 21 human pathogenic bacteria. The HE of arrayan and ayale showed the highest activity against enterobacteria (E. coli, Salmonella spp. and Shigella spp.) (MIC 0.25-2 mg/mL; MBC 0.5-16 mg/mL). The arrayan ME was the most active against the Gram-positive bacteria, showing Staphylococcus aureus the highest sensitivity (MIC 2 mg/mL; MBC 2-4 mg/mL). The presented results support the traditional uses of these plant materials for treating bacterial infectious diseases.

Nanchi (Byrsonima crassifolia), arrayán (Psidium sartorianum) y ayale (Crescentia alata) son plantas silvestres subutilizadas de México; sus frutos son comestibles y usados como medicamentos tradicionales contra infecciones bacterianas humanas (e.g. disentería bacilar). Sin embargo, los reportes científicos que avalen los usos y promuevan su consumo son escasos. En este trabajo se determinó, ensayo de micro-dilución en caldo, la Concentración Mínima Inhibitoria (CMI) y Concentración Mínima Bactericida (CMB), de los extractos de frutos (hexánico, EH; clorofórmico, EC; y metanólico, EM) contra 21 bacterias patógenas humanas. Los EH de arrayán y ayale mostraron la mayor actividad (CMI 0.25-2 mg/mL; CMB 0.5-16 mg/mL) contra enterobacterias (Escherichia coli, Salmonella spp. y Shigella spp.). El EM de arrayán fue el más activo contra bacterias Gram positivas, presentando Staphylococcus aureus la mayor sensibilidad (CMI 2 mg/mL; CMB 2-4 mg/mL). Estos resultados apoyan el uso tradicional de estos materiales en padecimientos asociados al tratamiento de infecciones bacterianas.

Physicochemical, nutritional and antibacterial characteristics of the fruit of Bromelia pinguin L.

Bromelia pinguin L. is a plant native to Sinaloa, Mexico, where its fruit is used as food or as a phytotherapeutic agent. The fruits of B. pinguin were characterized and they could be considered as a functional food. These fruits show an average weight of 13.7 g and a yellow color of high luminosity (b* = 43.2, L* = 74.5). The values for acidity (4.6%, as citric acid) and pH (3.7) of B. pinguin fruit are similar to those of citrics. The edible portion is characterized by a high content of vitamin C (126 mg/100 g), ash (10.6 g/100 g d.w.), crude fiber (3.4 g/100 g d.w.), calcium (1290 mg/100 g d.w.), magnesium (500 mg/100 g d.w.), manganese (2.95 mg/100 g d.w.) and it is a good source of zinc (2.8 mg/100 g d.w.). Polar fractions extracted from the pulp fruit showed activity against several genera of human pathogenic-bacteria (Staphylococcus, Streptococcus, Enterococcus, Salmonella, Shigella, Escherichia and Pseudomonas).