Antibiotic resistance in faecal microbiota of Greek healthy infants

Abstract

Increasing use of antibiotics for the treatment of infectious diseases and also for non-therapeutic reasons (agriculture, animal husbandry and aquaculture) has led to the increasing incidence of antibiotic resistance and the ineffectiveness of antimicrobial treatment. Commensal intestinal bacteria are very often exposed to the selective pressure of antimicrobial agents and may constitute a reservoir of antibiotic resistance determinants that can be transferred to pathogens. The present study aimed to investigate the antibiotic susceptibility profile and the presence of selected resistance genes in cocci isolated from the faecal microbiota of 35 healthy, full-term infants at 4, 30 and 90 days after delivery. A total of 148 gram-positive, catalase-negative cocci were isolated and tested for susceptibility to 12 different antibiotics by disk-diffusion technique. Multiplex PCR analysis was performed for the identification of Enterococcus spp. isolates and the simultaneous detection of vancomycin-resistance genes. PCR-based methodology was used also for identification of tetracycline and erythromycin resistance determinants. Identification results indicated E. faecalis as the predominant species (81 strains), followed by E. faecium, E. casseliflavus/E. flavescens and E. gallinarum. High prevalence of resistance to tetracycline (39.9%), erythromycin (35.1%), vancomycin (19.6%) and to nucleic acid synthesis inhibitors was detected. PCR data revealed 24 out of 52 erythromycin-resistant isolates carrying the ermB gene and 32 out of 59 tetracycline-resistant strains carrying tet genes, with tet(L) determinant being the most frequently detected. Only intrinsic vancomycin resistance (vanC1 and vanC2/C3) was reported among tested isolates. In conclusion, erythromycin and tetracycline acquired resistant traits are widespread among faecal cocci isolates from Greek, healthy infants under no apparent antimicrobial selective pressure.

Identification and characterization of tetracycline resistance in Lactococcus lactis isolated from Polish raw milk and fermented artisanal products

“…These results overlap with the results reported by other research groups, indicating that most of the antibioticresistant LAB strains are resistant to tetracycline and erythromycin (Devirgiliis et al, 2010). Similar results were obtained for both the bacteria isolated from the human digestive system (Mitsou et al, 2010) and as the bacteria isolated from dairy products Florez et al, 2005Florez et al, , 2007Gad et al, 2014;Nawaz et al, 2011). The reason for this may be the huge amount of tetracyclines that have been used for years in agriculture livestock farming as "growth promoters".…”

Mechanisms of and Risk Factors for Fluoroquinolone Resistance in Clinical Enterococcus faecalis Isolates from Patients with Urinary Tract Infections

“…An increase in antibiotic-resistant E. faecalis isolates has been encountered (16), and the emergence of QREF has recently been reported in several countries (18,27,22). It may be useful for both basic and clinical research to investigate the relationship between risk factors for fluoroquinolone resistance and its related mechanisms in order to prevent progressively increasing resistance to antibiotics.…”

The Intestinal Microbiome in Early Life: Health and Disease

“…In addition to conferring antibiotic resistance in infancy (106), antibiotic over usage can significantly disrupt the overall ecology of the gut microbiota, alter the abundances of resident gut bacteria, and potentially bias the child toward certain diseases (107–109). …”