Interference with Bacterial Conjugation and Natural Alternatives to Antibiotics: Bridging a Gap.

Horizontal gene transfer (HGT) in food matrices has been investigated under conditions that favor gene exchange. However, the major challenge lies in determining the specific conditions pertaining to the adapted microbial pairs associated with the food matrix. HGT is primarily responsible for enhancing the microbial repertoire for the evolution and spread of antimicrobial resistance and is a major target for controlling pathogens of public health concern in food ecosystems. In this study, we investigated Salmonella Heidelberg (SH) and Escherichia coli (EC) regarding gene exchange under conditions mimicking the industrial environment, with the coproducts whey (SL) and chicken juice (CJ). The S. Heidelberg strain was characterized by antibiotic susceptibility standards and PCR to detect the blaTEM gene. A concentration of 0.39 mg/mL was determined to evaluate the anti-conjugation activity of nanostructured lipid nanocarriers (NLCs) of essential oils to mitigate ß-lactam resistance gene transfer. The results showed that the addition of these coproducts promoted an increase of more than 3.5 (whey) and 2.5 (chicken juice) orders of magnitude in the conjugation process (p < 0.01), and NLCs of sage essential oil significantly reduced the conjugation frequency (CF) by 74.90, 90.6, and 124.4 times when compared to the transfers in the absence of coproducts and the presence of SL and CJ, respectively. For NLCs from olibanum essential oil, the decrease was 4.46-fold for conjugations without inhibitors and 3.12- and 11.3-fold in the presence of SL and CJ. NLCs associated with sage and olibanum essential oils effectively control the transfer of antibiotic resistance genes and are a promising alternative for use at industrial levels.

Caracterización de los plásmidos de cepas de escherichia coli aislados de coprocultivos de niños sanos / Characterization of plasmids of escherichia coli strains isolated from stool culture of healthy children

La microbiota intestinal representa una reserva potencial de organismos resistentes a los antimicrobianos, y el sitio donde los genes de resistencia pueden ser transferidos desde la microbiota comensal a los microorganismos virulentos. En este trabajo se caracterizaron los perfiles fenotípicos de resistencia a diversos agentes antimicrobianos, en aislados de Escherichia coli, obtenidos de niños sanos, menores de 5 años de edad, y la capacidad de transmisibilidad de esos determinantes de resistencia, mediante ensayos de conjugación. Los aislados de E. coli se obtuvieron partir de coprocultivos de niños sanos mediante el uso de placas de Mc Conkey suplementadas con ampicilina y se les determinó el perfil de resistencia a diversos antibióticos, para luego realizar ensayos de conjugación. A partir de 90 coprocultivos, fueron aisladas 33 cepas de E. coli resistentes a algún antibiótico, presentándose un 66,6% del total de las cepas resistentes en al menos dos antibióticos. Luego de los ensayos de conjugación, se encontró que un 47,4% de las cepas presenta plásmidos conjugativos, transfiriendo marcadores de resistencia. Los patrones generados por enzimas de restricción fueron distintos entre ellos. Estos resultados nos permiten sugerir que estos elementos extracromosomales sean los responsables de la rápida diseminación de la resistencia a los antimicrobianos en la población bacteriana de niños sanos.

Gastrointestinal microbiota represents the potential reserve of antimicrobial-resistant organisms, and the site where resistance genes can be transferred from the commensally microbiota to virulent microorganisms. In this work we characterized the phenotypic resistance profiles to various antimicrobial agents in strains of Escherichia coli isolated from healthy children, less than 5 years of age, and the ability of these determinants of resistance to be mobilized by conjugation. The isolation of E. coli strains from stool culture from healthy children was made through the use of Mc Conkey media supplemented with ampicillin. The profile of resistance to various antibiotics was determined and then conjugation was carried out. From 90-stool culture 33 strains of E. coli resistant to some antibiotic were isolated, 63.6% of bacteria were resistant to -at least- two antibiotic. It have be demonstrated that 47.4% of the isolates harbored conjugative plasmids, which can mobilize markers of resistance. Restriction profiles analysis showed that all patterns were different. These results allow us to suggest that these extracromosomals elements are responsible for the rapid spread of resistance to antimicrobials in the bacterial population of healthy children.

Bacteriological water quality in school's drinking fountains and detection antibiotic resistance genes.

The fecal coliform can contaminate water of human consumption causing problems to public health. Many of these microorganisms may contain plasmid and transfer them to other bacteria. This genetic material may confer selective advantages, among them resistance to antibiotics. The objectives of this study were to analyze the presence of fecal coliforms in water and at drinker surface, to identify the existence of plasmid, conducting studies of resistance to antibiotics, plasmid stability and capacity of bacterial conjugation. Were collected microorganisms in water of drinker surface and were used specific culture media and biochemical tests for identification of organisms, tests were performed by checking the resistance to antibiotics (ampicillin 10 µg, tetracycline 30 µg, and ciprofloxacin 5 µg), was performed extraction of plasmid DNA, plasmid stability and bacterial conjugation. Was obtained results of 31% of Salmonella spp. and 51% for other coliforms. Among the samples positive for coliforms, 27 had plasmid stable and with the ability to perform conjugation. The plasmids had similar forms, suggesting that the resistance in some bacteria may be linked to those genes extra chromosomal.

First identification of Tn916-like element in industrial strains of Lactobacillus vini that spread the tet-M resistance gene.

The open process used to ferment sugar cane juice or molasses to produce ethanol fuel is prone to contamination by bacterial cells of different species, in particular Lactobacilli. The situation can be exacerbated by the emergence of resistant cells to industrial antibiotics that are normally used to combat this contamination. In this work, two Lactobacillus vini isolates from ethanol distilleries were identified and found to be resistant to doxycycline, a tetracycline derivative, although sensitive to other antibiotics tested. The identification of these isolates was confirmed by sequencing the pheS gene and their clonal origin was shown by PCR-fingerprinting analysis. Moreover, the isolates were shown to carry the transposable element Tn916 that harboured the tet-M gene. Furthermore, conjugation experiments showed that both isolates were capable of transferring this element, and as a result, the tet-M gene, to Enterococcus faecalis reference strain. Finally, the identification of tetracycline resistance in the same distilleries in other Lactobacilli, suggested that inter-species transfer of antibiotic resistance may be occurring in the industrial environment, and thus impairing the efficiency of the antibiotic treatment and causing serious health concerns.

Resistencia antimicrobiana de bacterias aisladas de clínicas veterinarias de la ciudad de Ibagué, Colombia / Antimicrobial resistance of bacteria isolated from veterinary clinics in the city of Ibague, Colombia

Objetivo: Aislar bacterias que circulan en clínicas veterinarias de la ciudad de Ibagué, conocer su perfil de resistencia a antimicrobianos y en algunas, su capacidad de transferir dicha resistencia a bacterias sensibles. Materiales y métodos: Se tomaron muestras de 10 clínicas a las que se les realizó cultivo bacteriológico, identificación bioquímica, antibiograma y pruebas de conjugación bacteriana para transmitir dicha resistencia. El diseño metodológico fue de tipo cuasi-experimental, el análisis de los resultados se hizo mediante estadística descriptiva. Resultados: En todas las áreas de las 10 clínicas se encontraron bacterias potencialmente patógenas multirresistentes que pertenecían a 8 de 16 especies aisladas. Los microorganismos que aparecieron con mayor frecuencia en los diferentes sitios de las clínicas fueron: Staphylococcus intermedius, Acinetobacter baumannii, Pantoea agglomerans, Klebsiella pneumoniae y Burkhordelia cepacia. Los lugares donde se aislaron microorganismos multirresistentes con más frecuencia fueron el piso de consulta externa y la mesa de examen clínico. La resistencia se presentó principalmente a amoxicilina y cloranfenicol. El estudio muestra la presencia de patógenos potenciales de causar infecciones nosocomiales, que se constituyen en reservorio de genes de resistencia a los antibióticos para las bacterias patógenas no resistentes.

Objective: To isolate bacteria circulating in veterinary clinics in the city of Ibague for knowing its antimicrobial resistance profile and in some cases, its ability to transfer this resistance to susceptible bacteria. Materials and Methods: Samples of 10 clinics that underwent bacterial culture, biochemical identification, antimicrobial susceptibility testing and bacterial conjugation to transfer this resistance were taken. The methodological design was quasi-experimental and the analysis of the results was made using descriptive statistics. Results: In all areas of the 10 clinical multiresistant potentially pathogenic bacteria which belonged to 8 of 16 species isolated were found. The microorganisms that occurred more frequently in different clinical places were: Staphylococcus intermedius, Acinetobacter baumannii, Pantoea agglomerans, Klebsiella pneumoniae and Burkhordelia cepacia. The places where multiresistant microorganisms were most frequently isolated were the outpatients' floor and the clinical examination table. The resistance occurred mainly to amoxicillin and chloramphenicol. The study shows the presence of potential pathogens causing nosocomial infections, which constitute a reservoir of resistance genes to antibiotics for non-resistant pathogenic bacteria.