Microbial Shifts in the Intestinal Microbiota of Salmonella Infected Chickens in Response to Enrofloxacin

Abstract

Fluoroquinolones (FQs) are important antibiotics used for treatment of Salmonella infection in poultry in many countries. However, oral administration of fluoroquinolones may affect the composition and abundance of a number of bacterial taxa in the chicken intestine. Using 16S rRNA gene sequencing, the microbial shifts in the gut of Salmonella infected chickens in response to enrofloxacin treatments at different dosages (0, 0.1, 4, and 100 mg/kg b.w.) were quantitatively evaluated. The results showed that the shedding levels of Salmonella were significantly reduced in the high dosage group as demonstrated by both the culturing method and 16S rRNA sequencing method. The average values of diversity indices were higher in the control group than in the three medicated groups. Non-metric multidimensional scaling (NMDS) analysis results showed that the microbial community of high dosage group was clearly separated from the other three groups. In total, 25 genera were significantly enriched (including 6 abundant genera: Lactococcus, Bacillus, Burkholderia, Pseudomonas, Rhizobium, and Acinetobacter) and 23 genera were significantly reduced in the medicated groups than in the control group for the treatment period, but these bacterial taxa recovered to normal levels after therapy withdrawal. Additionally, 5 genera were significantly reduced in both treatment and withdrawal periods (e.g., Blautia and Anaerotruncus) and 23 genera (e.g., Enterobacter and Clostridium) were significantly decreased only in the withdrawal period, indicating that these genera might be the potential targets for the fluoroquinolones antimicrobial effects. Specially, Enterococcus was significantly reduced under high dosage of enrofloxacin treatment, while significantly enriched in the withdrawal period, which was presumably due to the resistance selection. Predicted microbial functions associated with genetic information processing were significantly decreased in the high dosage group. Overall, enrofloxacin at a dosage of 100 mg/kg b.w. significantly altered the microbial community membership and structure, and microbial functions in the chicken intestine during the medication. This study fully investigates the chicken intestinal microbiota in response to enrofloxacin treatment and identifies potential targets against which the fluoroquinolones may have potent antimicrobial effects. These results provide insights into the effects of the usage of enrofloxacin on chicken and will aid in the prudent and rational use of antibiotics in poultry industry.

Enrofloxacin shifts intestinal microbiota and metabolic profiling and hinders recovery fromSalmonella entericasubsp.entericaserovarTyphimuriuminfection in neonatal chickens

“…Here, we investigated the effects of enrofloxacin on the colonization of S. Typhimurium in the intestinal tracts of chickens. Our results showed that on days 7 and 14, S. Typhimurium was highly abundant in the cecum contents of mice treated with antibiotics, similar to previous reports (9,15,17). Thus, our findings showed that different concentrations of enrofloxacin altered the ability of S. Typhimurium to colonize the gut in chickens.…”

“…Quinolones, such as enrofloxacin, affect the composition and number of bacterial species in the chicken gut (9), thereby altering resistance to pathogen invasion. Indeed, bacteria residing in the gut can mediate the colonization of S. Typhimurium in the body by producing short-chain fatty acids (SCFAs), such as propionic acid, which inhibits S. Typhimurium growth by influencing the intracellular pH (10).…”

Resistance and Virulence Mechanisms of Escherichia coli Selected by Enrofloxacin in Chicken

“…In this study, no counterparts of the susceptible or resistant E. coli isolates were detected before drug administration. Sequencing of the 16S rRNA of the intestinal microbiota of specific-pathogen-free (SPF) chickens also confirmed that the number of E. coli isolates at the initial phase was low (10). All 330 E. coli isolates with low to high levels of resistance to FQs were selected from the middle-dosage group (4 mg/kg of b.w.)…”

Evaluation of Curcumin and Copper Acetate Against Salmonella Typhimurium Infection, Intestinal Permeability, and Cecal Microbiota Composition in Broiler Chickens

“…Coprobacillus, Clostridium, and Eubacterium have an important role in the production of SCFAs essential amino acids and the digestion of non-starch polysaccharides, which stimulate the production of SCFAs for metabolic balance [68,70]. Likewise, it has been reported that the reduction of Clostridium and the maintenance of Eubacterium and Coprobacillus levels could be related to the effectiveness of the treatments since they represent a positive effect in the maintenance of intestinal homeostasis [70][71][72].…”