EVOLUTIONARY POTENTIAL OF OXYIMINO-BETA-LACTAM RESISTANCE DETERMINANTS IN ANIMALS AND IDENTIFICATION OF NEW ENZYME-INHIBITORS FOR VETERINARY USE

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Deciphering the role of cyanobacteria in water resistome: Hypothesis justifying the antibiotic resistance (phenotype and genotype) in Planktothrix genus

Publication . Dias, Elsa; Oliveira, Micaela; Manageiro, Vera; Vasconcelos, Vitor; Caniça, Manuela

The importance of environmental microorganisms in the emergence and dissemination of antibiotic resistance is an undeniable fact. However, cyanobacteria are not seen yet as putative players in the dynamic of environmental resistome, despite their ubiquity in water environments, where they are exposed to antibiotic pollution and in straight contact with native and pathogenic bacteria harboring antibiotic resistance genes (ARGs). In this work we evaluated the susceptibility of 8 strains of Planktothrix agardhii (from surface freshwaters reservoirs) and 8 strains of Planktothrix mougeotii (from a wastewater treatment plant) to several classes of antibiotics, using a microplate dilution method previously described by us. We also search for ARGs in those strains by molecular methods. None of the 16 tested strains were susceptible to trimethoprim, nalidixic acid and norfloxacin, from 0.0015–1.6 mg/L, but all were susceptible to streptomycin, gentamicin, kanamycin, ceftazidime and ceftriaxone. The minimum inhibitory concentrations (MICs) ranged between 0.05–0.8 mg/L for the aminoglycosides and 0.4–1.6 mg/L for the two β‑lactams. Major differences were found in the susceptibility to amoxicillin and tetracycline, with P. agardhii being susceptible (MIC of 0.05 mg/L and 0.4 mg/L, respectively) and P. mougeotii not susceptible. These distinct responses might be due to differences between species. However, the lower susceptibility of wastewater strains suggests that antibiotic resistance phenotype of cyanobacteria is related with their habitat. The failure to detect acquired genes conferring resistance to trimethoprim/quinolones, strongly supports the hypothesis that cyanobacteria are intrinsically resistant to these antibiotics. Interestingly, we detected a class-1-type integron and a sul1 gene in 3 strains of both P. agardhii and P. mougeotii, which supports the possibility of cyanobacteria to acquire and transfer antibiotic resistance determinants. In conclusion, the identification of ARGs and related integrons, as well as the reduced susceptibility to some antibiotics, suggests that cyanobacteria may play a role on environmental resistome.

2018-10-12Journal article

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Biochemical characterization of CTX-M-166, a new CTX-M β-lactamase produced by a commensal Escherichia coli isolate

Publication . Manageiro, Vera; Graça, Rafael; Ferreira, Eugénia; Clemente, Lurdes; Bonnet, Richard; Caniça, Manuela

In this study, we biochemically characterized the new CTX-M-166 β-lactamase detected in a ceftiofur-resistant Escherichia coli recovered in May 2014 from a six-week-old Gallus gallus broiler flock in an industrial poultry unit in the central region of Portugal.

2017-06Journal article

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New insights into resistance to colistin and third-generation cephalosporins of Escherichia coli in poultry, Portugal: Novel blaCTX-M-166 and blaESAC genes

Publication . Manageiro, Vera; Clemente, Lurdes; Graça, Rafael; Correia, Ivone; Albuquerque, Teresa; Ferreira, Eugénia; Caniça, Manuela

The increasing incidence of intestinal colonization with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and Gram negative organisms that has been observed in food animals such as poultry, cattle and pigs, are suggestive that animals, food and environment are potential sources of ESBL-producing bacteria. Hence, the aim of this study was to characterized commensal E. coli obtained from healthy broiler and turkey flocks at slaughter for the presence of penicillinases-, ESBL-, extended-spectrum AmpC (ESAC)-, plasmid-mediated quinolone resistance- and MCR-encoding genes. Study of clonal relatedness showed genetic diversity among CTX-M-type, SHV-12 and TEM-52 producing isolates with human isolates of the same type, was also assessed. We detected that eleven (5.4%, 11/202) and forty-five (2.2%, 45/185) E. coli isolates from broilers and turkeys, respectively, carried blaESBLor blaESACgenes and two isolates from turkeys carried mcr-1 gene. A new variant blaCTX-M-166was reported in a multidrug resistant isolate from a broiler flock. Overall, we detected a diversity of resistance mechanisms among E. coli from food-producing animals, all of them with high importance at a public health level.

2017-12-18Journal article

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First report on MRSA CC398 recovered from wild boars in the north of Portugal. Are we facing a problem?

Publication . Sousa, Margarida; Silva, Nuno; Manageiro, Vera; Ramos, Sónia; Coelho, António; Gonçalves, David; Caniça, Manuela; Torres, Carmen; Igrejas, Gilberto; Poeta, Patrícia

The aim of the present study was to evaluate the resistance of Staphylococcus aureus recovered from wild boars, to analyze their genetic lineages, and to investigate the susceptibility to oxacillin. Samples from mouth and nose of 45 wild boars (Sus scrofa) were collected during hunt activity from November 2012 to January 2013 in the North of Portugal. S. aureus isolates were recovered from 30 of these samples (33%); one isolate/sample was further studied. The susceptibility of the isolates was tested by disk-diffusion test against 14 antimicrobial agents and minimal inhibitory concentration was used to test oxacillin according to EUCAST guidelines. The genetic lineages of S. aureus were characterized by agr-typing, spa-typing and MLST. From the 30 isolates, 18 S. aureus were susceptible to all antibiotics tested and 7 presented resistance to one or more of the following antibiotics: penicillin (n=3), oxacillin (n=4), cefoxitin (n=1), clindamycin (n=2), gentamicin (n=1), fusidic acid (n=1), ciprofloxacin (n=2), tetracycline (n=1) and linezolid (n=1). One MRSA CC398 (spa-type t899) isolate was detected (oxacillin MIC=32mg/L and mecA-positive), which presented resistance to penicillin, tetracycline, and ciprofloxacin and contained the genes of immune evasion cluster (IEC) system (type B). The 29 methicillin-susceptible isolates were typed as ST1 (t1533), ST133 (t3583), ST1643 (t10712), ST2328 (t3750) and the new STs (3220, 3222, 3223, 3224) associated to new spa-types t14311 and t14312. The agr-types I, II, III and IV were identified. It is a matter of concern when MRSA and some specific lineages of S. aureus are taken as commensal habitants of the skin and nose of wild animals and are characterized with resistance to various antimicrobial agents in clinical use.

2017-10-15Journal article

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Genetic Background and Expression of the New qepA4 Gene Variant Recovered in Clinical TEM-1- and CMY-2-Producing Escherichia coli

Publication . Manageiro, Vera; Félix, David; Jones-Dias, Daniela; Sampaio, Daniel A; Vieira, Luís; Sancho, Luísa; Ferreira, Eugénia; Caniça, Manuela

A new QepA4 variant was detected in an O86:H28 ST156-fimH38 Escherichia coli, showing a multidrug-resistance phenotype. PAβN inhibition ofqepA4-harboring transconjugant resulted in increase of nalidixic acid accumulation. TheqepA4andcatA1genes were clustered in a 26.0-kp contig matching an IncF-type plasmid, and containing a Tn21-type transposon with multiple mobile genetic elements. This QepA variant is worrisome because these determinants might facilitate the selection of higher-level resistance mutants, playing a role in the development of resistance, and/or confer higher-level resistance to fluoroquinolones in association with chromosomal mutations.

2017-10-09Journal article

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