Genetic characterization of the mechanisms of resistance to amoxicillin/clavulanate and third-generation cephalosporins in Salmonella enterica from three Spanish hospitals

The mechanisms of antimicrobial resistance were characterized in 90 Salmonella enterica isolates either resistant or with intermediate resistance to amoxicillin/clavulanate (AMCR/I) or resistant to third-generation cephalosporins (C3GR). These isolates were recovered in three Spanish hospitals during 2007-2009. The C3GR phenotype was expressed by three isolates that carried the following extended-spectrum β-lactamase genes: phage-associated blaCTX M-10 in S. Virchow, blaCTX-M-14a surrounded by ISEcp1 and IS903 in S. Enteritidis, and blaCTX-M-15 linked to ISEcp1 and orf477 in S. Gnesta (first description in this serotype). The AMCR/I phenotype was found in 87 isolates (79 S. Typhimurim, 7 S. Enteritidis, and one S. Thompson). The blaPSE-1 gene, followed by blaOXA-1 was mostly found among S. Typhimurim, and the blaTEM-1 gene among S. Enteritidis. Three different gene combinations [blaPSE-1+floR+aadA2+sul+tet(G); blaOXA-1+catA+aadA1/strA-strB+sul+tet(B) and blaTEM-1+cmlA1+aadA/strA-strB+sul+tet(A)/tet(B) genes] were associated with the ampicillin-chloramphenicol-streptomycin-sulfonamides-tetracycline phenotype in 68 AMCR/I S. enterica isolates. Class 1 integrons were observed in 79% of the isolates and in most of them (45 isolates) two integrons including the aadA2 and blaPSE-1 gene cassettes, respectively, were detected. The blaOXA-1+aadA1 arrangement was detected in 23 isolates, and the aac(6′)-Ib-cr+blaOXA-1+catB3+arr3 in another one. Non-classicclass 1 integrons were found in three isolates: dfrA12+orfF+aadA2+cmlA1+aadA1 (1 isolate), dfrA12+orfF+aadA2+cmlA1+aadA1+qacH+IS440+sul3 (1 isolate) and dfrA12+orfF+aadA2+cmlA1+aadA1+qacH+IS440+ sul3+orf1+mef(B)Δ-IS26 (1 isolate). Taken together, these results underline the need for clinical concern regarding β-lactam resistance in Salmonella and thus for vigilant monitoring

Pseudomonas aeruginosa from river water: antimicrobial resistance, virulence and molecular typing

Pseudomonas aeruginosa isolates were recovered from surface river water samples in La Rioja region (Spain) to characterise their antibiotic resistance, molecular typing and virulence mechanisms. Fifty-two P. aeruginosa isolates were isolated from 15 different water samples (45.4%) and belonged to 23 different pulsed-field electrophoresis (PFGE) patterns. All isolates were susceptible to all antibiotics tested, except one carbapenem-resistant P. aeruginosa that showed a premature stop codon in OprD porin. Twenty-two sequence types (STs) (six new ones) were detected among 29 selected P. aeruginosa (one strain with a different PFGE pattern per sample), with ST274 (14%) being the most frequent one. O:6 and O:3 were the predominant serotypes (31%). Seven virulotypes were detected, being 59% exoS-exoY-exoT-exoA-lasA-lasB-lasI-lasR-rhlAB-rhlI-rhlR-aprA-positive P. aeruginosa. It is noteworthy that the exlA gene was identified in three strains (10.3%), and the exoU gene in seven (24.1%), exoS in 18 (62.1%), and both exoS and exoU genes in one strain. High motility ranges were found in these strains. Twenty-seven per cent of strains produced more biofilm biomass, 90% more pyorubin, 83% more pyocyanin and 65.5% more than twice the elastase activity compared with the PAO1 strain. These results highlight the importance of rivers as temporary reservoirs and sources of P. aeruginosa transmission, and show the importance of their epidemiological surveillance in the environment

Durability Assessment of a Plasma-Polymerized Coating with Anti-Biofilm Activity against L. monocytogenes Subjected to Repeated Sanitization

Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).[EN] Biofilm formation on food-contact surfaces is a matter of major concern causing food safety and spoilage issues to this sector. The aim of this study was to assess the durability of the anti-biofilm capacity of a plasma-polymerized coating composed of a base coating of (3-aminopropyl) triethoxysilane (APTES) and a functional coating of acrylic acid (AcAc). Coated and uncoated AISI 316 stainless steel (SS) plates were subjected to five sanitization cycles with sodium hypochlorite (0.05%) and peracetic acid (0.5%). The effectiveness of the coating for the inhibition of multi-strain Listeria monocytogenes biofilm formation was confirmed using a three-strain cocktail, which was grown on the SS plates at 12◦ C for 6 days. Compared to the uncoated SS, relative biofilm productions of 14.6% on the non-sanitized coating, 27.9% on the coating after sanitization with sodium hypochlorite, and 82.3% on the coating after sanitization with peracetic acid were obtained. Morphological and physicochemical characterization of the coatings suggested that the greater anti-biofilm effectiveness after sanitization with sodium hypochlorite was due to the high pH of this solution, which caused a deprotonation of the carboxylic acid groups of the functional coating. This fact conferred it a strong hydrophilicity and negatively charged its surface, which was favorable for preventing bacterial attachment and biofilm formation.SIThis publication is based upon work from COST Action CA19110—PlAgri, supported by COST (European Cooperation in Science and Technology-www.cost.eu). XPS tests were conducted by the Advanced Microscopy Laboratory (LMA) of The Institute of Nanoscience of Aragón (INA), University of Zaragoza. The authors are thankful to the LMA-INA for the access to their equipment and their expertise. The AFM images were taken by the Central Research Support Service (SCAI) of the University of Málaga (UMA). The author P. Fernández-Gómez is grateful to Junta de Castilla y León and the European Social Fund (ESF) for awarding her a predoctoral grant (BOCYL-D-15122017-4). The author M. Oliveira is in receipt of a Juan de la Cierva contract IJC2018-035523-I awarded by the Spanish Ministry of Science, Innovation, and Universities MCIN/AEI/10.13039/501100011033. The author E. Sainz-García, as researcher of the University of La Rioja, is thankful to the postdoctoral training program funded by the Plan Propio of the University of La Rioja. The authors I. Muro-Fraguas and A. Sainz-García are thankful to the program of pre-doctoral contracts for the training of research staff that is funded by the University of La Rioja.This study is part of the Research, Development and Innovation projects AGL2017-82779- C2-R and PID2020-113658RB-C2, funded by MCIN/AEI/10.13039/501100011033 and by ERDF “A way to make Europe”

Antimicrobial resistance and associated risk factors in Escherichia coli isolated from Peruvian dogs: A focus on extended-spectrum β-lactamases and colistin

Background and Aim: Established antimicrobial resistance (AMR) surveillance in companion animals is lacking, particularly in low-middle-income countries. The aim of this study was to analyze AMR and its risk factors in Escherichia coli isolated from dogs at two veterinary centers in Lima (Peru). Materials and Methods: Ninety dogs were included in the study. Antimicrobial susceptibility was established by disk diffusion, whereas microdilution was used to determine colistin susceptibility. Mechanisms related to extended-spectrum β-lactamases (ESBL) and colistin resistance were determined by polymerase chain reaction. Clonal relationships of colistin-resistant isolates were assessed by XbaI-pulsed-field gel electrophoresis. Results: Thirty-five E. coli strains were isolated. High levels of resistance to ampicillin (57.1%), nalidixic acid (54.3%), tetracycline (48.6%), and azithromycin (25.7%) were detected. Cephalosporin resistance levels were ≥20% and those for colistin were 14.3%. Twelve (34.2%) isolates were ESBL producers; of these, six blaCTX-M-55 (50.0%), 2 (16.6%) blaCTX-M-15, and 2 (16.6%) blaCTX-M-8-like genes were found. The five colistin-resistant isolates were clonally unrelated, with four of them presenting amino acid codon substitutions in the mgrB gene (V8A) or mutations in the mgrB promoter (a12g, g98t, and c89t). Furthermore, dog age, <6 years (p = 0.027) and raw diet (p = 0.054) were associated with resistance to a greater number of antibiotic families. Conclusion: Despite small number of samples included, the study found that dogs studied were carriers of multidrug-resistant E. coli, including last-resort antimicrobials, representing a public health problem due to close contact between dogs and humans. This issue suggests the need for larger studies addressed to design strategies to prevent the spread of resistant micro-organisms in small animal clinics and domestic settings