First evidence of blaNDM-1 and blaOXA-23 carbapenemase genes in human body lice infesting a second-hand T-shirt in a street market in Italy.

Background: The spread of carbapenems resistance is a public health concern. The main group of carbapenemases encoding the β-lactamases activity (bla genes) is the Metallo-β-lactamases (MBLs).

Methods: The presence of carbapenemase blaOXA-23-like, blaOXA-40-like, blaOXA-51-like, blaOXA-58-like, and blaNDM-1 genes was screened by real time PCR in 26 Pediculus humanus insects identified from second-hand clothes in a local market in Central Italy. Bacteria diversity was also characterized through shotgun metagenomic amplification for a deep sequencing of the host-associated bacterial microbiomes.

Results: The blaOXA-23 and blaNDM-1 carbapenemases genes were found and metagenomic analysis showed a great presence of Acinetobacter species.

Conclusions: These results suggest a new potential transmission path for carbapenemase gene spread through bacteria ingested by insects infesting humans.