Organic and conventional fruits and vegetables contain equivalent counts of Gram-negative bacteria expressing resistance to antibacterial agents.
Resistance to antibiotics is a major public health problem which might culminate in outbreaks caused by pathogenic bacteria untreatable by known antibiotics. Most of the genes conferring resistance are acquired horizontally from already resistant commensal or environmental bacteria. Food contamination by resistant bacteria might be a significant source of resistance genes for human bacteria but has never been precisely assessed, nor is it known whether organic products differ in this respect from conventionally produced products. We showed here, on a large year-long constructed sample set containing 399 products that, irrespective of their mode of production, raw fruits and vegetables are heavily contaminated by Gram-negative bacteria (GNB) resistant to multiple antibiotics. Most of these bacteria originate in the soil and environment. We focused on non-oxidative GNB resistant to third-generation cephalosporins, because of their potential impact on human health. Among them, species potentially pathogenic for immunocompetent hosts were rare. Of the products tested, 13% carried bacteria producing extended-spectrum beta-lactamases, all identified as Rahnella sp. which grouped into two phylotypes and all carrying the bla(RAHN) gene. Thus, both organic and conventional fruits and vegetables may constitute significant sources of resistant bacteria and of resistance genes.
Ruimy
Raymond
R
EA 6934 << Résistance Bactérienne in vivo >> Université Paris Diderot, and Centre National de Référence sur la Résistance aux Antibiotiques, Hôpital Bichat Claude Bernard, APHP, Paris, France.
Brisabois
Anne
A
Bernede
Claire
C
Skurnik
David
D
Barnat
Saïda
S
Arlet
Guillaume
G
Momcilovic
Sonia
S
Elbaz
Sandrine
S
Moury
Frédérique
F
Vibet
Marie-Anne
MA
Courvalin
Patrice
P
Guillemot
Didier
D
Andremont
Antoine
A
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000502:physiology*; D005506:Food Contamination; D005638:Fruit / Q000382:microbiology*; D022761:Gene Transfer, Horizontal; D006090:Gram-Negative Bacteria / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014675:Vegetables / Q000382:microbiology*; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; D001618:beta-Lactamases