High Colonization Rate and Heterogeneity of ESBL- and Carbapenemase-Producing <i>Enterobacteriaceae</i> Isolated from Gull Feces in Lisbon, Portugal

• Main Authors: Marta Aires-de-Sousa, Claudine Fournier, Elizeth Lopes, Hermínia de Lencastre, Patrice Nordmann, Laurent Poirel
• Format: Article
• Language: English
• Published: MDPI AG 2020-09-01
• Series: Microorganisms
• Subjects: carbapenemase; gulls; Portugal; ESBL; <i>Enterobacteriaceae</i>
• Online Access: https://www.mdpi.com/2076-2607/8/10/1487

In order to evaluate whether seagulls living on the Lisbon coastline, Portugal, might be colonized and consequently represent potential spreaders of multidrug-resistant bacteria, a total of 88 gull fecal samples were screened for detection of extended-spectrum β-lactamase (ESBL)- or carbapenemase-producing <i>Enterobacteriaceae</i> for methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) and for vancomycin-resistant Enterococci (VRE). A large proportion of samples yielded carbapenemase- or ESBL-producing <i>Enterobacteriaceae</i> (16% and 55%, respectively), while only two MRSA and two VRE were detected. Mating-out assays followed by PCR and whole-plasmid sequencing allowed to identify carbapenemase and ESBL encoding genes. Among 24 carbapenemase-producing isolates, there were mainly <i>Klebsiella pneumoniae</i> (50%) and <i>Escherichia coli</i> (33%). OXA-181 was the most common carbapenemase identified (54%), followed by OXA-48 (25%) and KPC-2 (17%). Ten different ESBLs were found among 62 ESBL-producing isolates, mainly being CTX-M-type enzymes (87%). Co-occurrence in single samples of multiple ESBL- and carbapenemase producers belonging to different bacterial species was observed in some cases. Seagulls constitute an important source for spreading multidrug-resistant bacteria in the environment and their gut microbiota a formidable microenvironment for transfer of resistance genes within bacterial species.