[Molecular analysis of fluoroquinolones and macrolides resistance in Campylobacter jejuni isolates from humans, bovine and chicken meat]. / Análisis molecular de la resistencia a fluoroquinolonas y macrólidos en aislados de Campylobacter jejuni de humanos, bovinos y carne de ave.

BACKGROUND: Campylobacter sp.- one of the leading causes of bacterial food-borne gastrointestinal illness worldwide- is increasingly resistant to fluoroquinolone and macrolide antimicrobials, which has become a major concern for public health. OBJECTIVE: To describe the susceptibility patterns of Campylobacter jejuni strains to erythromycin and ciprofloxacin and to explore the origin of its resistance in human isolates. MATERIAL AND METHOD: In this study, fifty-five ciprofloxacin and erythromycin susceptibility patterns of C. jejuni strains isolated from humans with diarrheal disease, performed by broth microdilution MIC, were compared with 55 and 44 isolates from chicken meat and bovines respectively, obtained from the Metropolitan Region, Chile. RESULTS: Of the 55 human isolates of C. jejuni, 33 (60%) were resistant to ciprofloxacin and all were sensitive to erythromycin. Of the 55 isolates from chicken meat, 32 (58.2%) were resistant to ciprofloxacin and 1.8% were resistant to erythromycin. Of the 44 isolates of C. jejuni from cattle, 8 (18.2%) were resistant to ciprofloxacin and all were sensitive to erythromycin. Four PFGE patterns matched with certain resistance profiles and grouped isolates from human and animal. CONCLUSION: The findings showed continued effectiveness of erythromycin for campylobacteriosis and a high percentage of C. jejuni strains ciprofloxacin-resistant. This is interesting because it is considered that the presence of ciprofloxacin resistant strains in broiler meat can be in part the source of resistance to this antimicrobial in humans.

Prevalence of Salmonella in Eggs from Conventional and Cage-Free Egg Production Systems and the Role of Consumers in Reducing Household Contamination.

Salmonella is one of the leading causes of foodborne disease worldwide, usually related to contaminated poultry or poultry products, such as eggs. Since egg contamination with Salmonella depends on multiple factors that make it challenging to control, consumers' knowledge about food safety and the proper handling of eggs is crucial. The aims of the study were (1) to determine the prevalence of Salmonella in eggs from conventional and alternative production systems, (2) to characterize the Salmonella isolates according to phenotypic-genotypic and antimicrobial-resistant traits, and (3) to understand how consumers manage the hazards related to egg contamination in the household. A total of 426 egg samples were analyzed (conventional systems = 240; alternative systems = 186). Culture-based and molecular microbiological methods were used to identify Salmonella and bioinformatics analysis of whole genome sequences was used to determine the serotype and antimicrobial-resistant genes. Salmonella enterica serotype Enteritidis was detected only in eggs from alternative systems (1.1%, 2/186). Isolates showed resistance to nalidixic acid (100%, 2/2), and the aac(6')-Iaa gene and a mutation in the gyrA gene were identified in both isolates. Overall, consumers demonstrated knowledge regarding food safety; however, many still engage in practices that pose a risk of acquiring foodborne illnesses.

Antibacterial Effect of Copper on Microorganisms Isolated from Bovine Mastitis.

The antimicrobial properties of copper have been recognized for several years; applying these properties to the prevention of diseases such as bovine mastitis is a new area of research. The aim of the present study was to evaluate in vitro the antimicrobial activity of copper on bacteria isolated from subclinical and clinical mastitis milk samples from two regions in Chile. A total of 327 microorganisms were recovered between March and September 2013, with different prevalence by sample origin (25 and 75% from the central and southern regions of Chile, respectively). In the central region, Escherichia coli and coagulase negative Staphylococci (CNS) were the most frequently detected in clinical mastitis cases (33%), while in the southern region S. uberis, S. aureus, and CNS were detected with frequencies of 22, 21, and 18%, respectively. Antibiotic susceptibility studies revealed that 34% of isolates were resistant to one or more antibiotics and the resistance profile was different between bacterial species and origins of isolation of the bacteria. The minimum inhibitory concentration of copper (MIC-Cu) was evaluated in all the isolates; results revealed that a concentration as low as 250 ppm copper was able to inhibit the great majority of microorganisms analyzed (65% of isolates). The remaining isolates showed a MIC-Cu between 375 and 700 ppm copper, and no growth was observed at 1000 ppm. A linear relationship was found between the logarithm of viable bacteria number and time of contact with copper. With the application of the same concentration of copper (250 ppm), CNS showed the highest tolerance to copper, followed by S. uberis and S. aureus; the least resistant was E. coli. Based on these in vitro results, copper preparations could represent a good alternative to dipping solutions, aimed at preventing the presence and multiplication of potentially pathogenic microorganisms involved in bovine mastitis disease.

Different Transcriptional Responses from Slow and Fast Growth Rate Strains of Listeria monocytogenes Adapted to Low Temperature.

Listeria monocytogenes has become one of the principal foodborne pathogens worldwide. The capacity of this bacterium to grow at low temperatures has opened an interesting field of study in terms of the identification and classification of new strains of L. monocytogenes with different growth capacities at low temperatures. We determined the growth rate at 8°C of 110 strains of L. monocytogenes isolated from different food matrices. We identified a group of slow and fast strains according to their growth rate at 8°C and performed a global transcriptomic assay in strains previously adapted to low temperature. We then identified shared and specific transcriptional mechanisms, metabolic and cellular processes of both groups; bacterial motility was the principal process capable of differentiating the adaptation capacity of L. monocytogenes strains with different ranges of tolerance to low temperatures. Strains belonging to the fast group were less motile, which may allow these strains to achieve a greater rate of proliferation at low temperature.

Análisis molecular de la resistencia a fluoroquinolonas y macrólidos en aislados de Campylobacter jejuni de humanos, bovinos y carne de ave / Molecular analysis of fluoroquinolones and macrolides resistance in Campylobacter jejuni isolates from humans, bovine and chicken meat

Background: Campylobacter sp.- one of the leading causes of bacterial food-borne gastrointestinal illness worldwide- is increasingly resistant to fluoroquinolone and macrolide antimicrobials, which has become a major concern for public health. Objective: To describe the susceptibility patterns of Campylobacter jejuni strains to erythromycin and ciprofloxacin and to explore the origin of its resistance in human isolates. Material and Method: In this study, fifty-five ciprofloxacin and erythromycin susceptibility patterns of C. jejuni strains isolated from humans with diarrheal disease, performed by broth microdilution MIC, were compared with 55 and 44 isolates from chicken meat and bovines respectively, obtained from the Metropolitan Region, Chile. Results: Of the 55 human isolates of C. jejuni, 33 (60%) were resistant to ciprofloxacin and all were sensitive to erythromycin. Of the 55 isolates from chicken meat, 32 (58.2%) were resistant to ciprofloxacin and 1.8% were resistant to erythromycin. Of the 44 isolates of C. jejuni from cattle, 8 (18.2%) were resistant to ciprofloxacin and all were sensitive to erythromycin. Four PFGE patterns matched with certain resistance profiles and grouped isolates from human and animal. Conclusion: The findings showed continued effectiveness of erythromycin for campylobacteriosis and a high percentage of C. jejuni strains ciprofloxacin-resistant. This is interesting because it is considered that the presence of ciprofloxacin resistant strains in broiler meat can be in part the source of resistance to this antimicrobial in humans.

Introducción: El incremento de la resistencia en Campylobacter sp. (una de las principales causas de gastroenteritis bacteriana de origen alimentario) a fluoro-quinolonas y macrólidos, es un problema en salud pública. Objetivo: Conocer los patrones de susceptibilidad in vitro de Campylobacter jejuni a eritromicina y ciprofloxacina y conocer el origen de su resistencia en aislados de humanos. Material y Método: En este estudio, se compararon las susceptibilidades a ciprofloxacina y eritromicina -CIM efectuadas por microdilución en caldo- de 55 aislados de C. jejuni provenientes de humanos con enterocolitis, con 55 aislados de carne de pollo y 44 de bovinos obtenidos en la Región Metropolitana, Chile. Resultados: De 55 aislados de C. jejuni de humanos, 33(60%) presentaron resistencia a ciprofloxacina y todos presentaron susceptibilidad a eritromicina. De 55 aislados procedentes de carne de pollo, 32 (58,2%) presentaron resistencia a ciprofloxacina y un aislado resultó resistente a eritromicina (1,8%). De 44 aislados de bovinos, 8(18,2%) presentaron resistencia a ciprofloxacina y todos resultaron sensibles a eritromicina. Cuatro patrones de electroforesis a campo pulsado coincidieron en sus perfiles de resistencia y agruparon aislados de origen humano y animal. Conclusiones: Los resultados muestran que eritromicina continúa siendo efectiva para el tratamiento de la campilobacteriosis y que existe un alto porcentaje de cepas resistentes a ciprofloxacina. Se considera probable que la presencia de cepas resistentes a ciprofloxacina en la carne de pollo puede ser en parte el origen de la resistencia a este fármaco en humanos.