title: Lettuce and fruits as a source of multidrug resistant Acinetobacter spp.
abstract: The role of ready-to-eat products as a reservoir of pathogenic species of Acinetobacter remains unclear. The objective of the present study was to evaluate the presence of Acinetobacter species in lettuces and fruits marketed in Portugal, and their susceptibility to antimicrobials. Acinetobacter spp. were isolated from 77.9% of the samples and these microorganisms were also found as endophytes (i.e. present within the plant tissue) in 12 of 20 samples of lettuces analysed. Among 253 isolates that were identified as belonging to this genus, 181 presented different PFGE profiles, representing different strains. Based on the analysis of the partial sequence of rpoB, 175 strains were identified as members of eighteen distinct species and the remaining six strains may represent five new candidate species since their rpoB sequence similarities with type strains were less than 95%. Acinetobacter calcoaceticus and Acinetobacter johnsonii were the most common species, both with the frequency of 26.5%; and 11% of the strains belong to the Acinetobacter baumannii group (i.e. A. baumannii, Acinetobacter pittii, Acinetobacter seifertii and Acinetobacter nosocomialis), which is most frequently associated with nosocomial infections. Overall, the strains were least susceptible to piperacillin (80.1%), piperacillin-tazobactam (64.1%), ceftazidime (43.1%), ciprofloxacin (16.6%), trimethoprim-sulfamethoxazole (14.9%), imipenem (14.4%) and colistin (13.3%). The most active antimicrobials were minocycline and tetracycline, with 0.6% and 3.9% of strains resistant, respectively. About 29.8% of the strains were classified as multidrug-resistant (MDR), 4.4% as extensively drug-resistant (XDR) and the prevalence of MDR strains within the A. baumannii group (25%) was similar to other species (30.4%). The presence of clinically important species as well as MDR strains in lettuces and fruits may be a threat to public health considering that they may transmit these pathogens to environments such as the community and hospital settings.
authors.affiliation: Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Carvalheira
authors.affiliation: Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401, Porto, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Silva
authors.affiliation: Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401, Porto, Portugal. Electronic address: pcteixeira@porto.ucp.pt.
authors.forename: Paula
authors.initials: P
authors.lastname: Teixeira
mesh_terms: D000150:Acinetobacter / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D060026:Endophytes / Q000302:isolation & purification; D005516:Food Microbiology; D005638:Fruit / Q000382:microbiology*; D018545:Lactuca / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D008911:Minocycline / Q000494:pharmacology; D011174:Portugal; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D013752:Tetracycline; D008911:Minocycline
keywords: A. baumannii group; Acinetobacter spp.; Antimicrobial resistance; Fruit; Lettuce; Multidrug-resistance; Ready-to-eat products