Browsing by Author "Silva, Nuno"
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- Antimicrobial resistance determinants in Staphylococcus spp. recovered from birds of prey in PortugalPublication . Sousa, Margarida; Silva, Nuno; Igrejas, Gilberto; Silva, Filipe; Sargo, Roberto; Alegria, Nuno; Benito, Daniel; Gómez, Paula; Lozano, Carmen; Gómez-Sanz, Elena; Torres, Carmen; Caniça, Manuela; Poeta, PatríciaAntibiotic resistance among wild animals represent an emerging public health concern. The objective of this study was to analyze the staphylococcal nasal microbiota in birds of prey and their content in antimicrobial resistance determinants. Nasal samples from 16 birds of prey were collected, swabs were dipped and incubated into BHI broth [6.5% NaCl] and later seeded on manitol salt agar and oxacillin-resistance screening agar base media. Staphylococcal colonies were isolated from both media and were identified by biochemical and molecular methods. Susceptibility testing to 18 antimicrobial agents was performed by disk-diffusion method. Six of the 16 tested animals carried staphylococci (37.5%) and 7 isolates of the following species were recovered: Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Staphylococcus sciuri rodentium, Staphylococcus cohnii urealitycum, and Staphylococcus gallinarum. The S. aureus isolate was penicillin-resistant (with blaZ gene) but methicillin-susceptible and was ascribed to spa-type t012, sequence-type ST30 and agr-type III. The S. epidermidis isolate carried blaZ, mecA, mrs(A/B), mphC, tet(K), drfA, and fusC genes, ica operon, and was typed as ST35. The genes ant6′-Ia, tet(K), tet(L), dfrG, cat221, cat194, and cat223 were detected in S. saprophyticus or S. gallinarum isolates. Birds of prey seem to be a natural reservoir of S. aureus and coagulase-negative staphylococci resistant to multiple antibiotics. Due to the convergence between habitats, the contact between wildlife, other animals and humans is now more common and this involves an increased possibility of interchange of these microorganisms in the different ecosystems.
- First report of CTX-M producing Escherichia coli, including the new ST2526, isolated from beef cattle and sheep in PortugalPublication . Ramos, Sónia; Igrejas, Gilberto; Silva, Nuno; Jones-Dias, Daniela; Capelo-Martinez, José-Luís; Caniça, Manuela; Poeta, PatríciaThe prevalence of extended-spectrum beta-lactamase-containing Escherichia coli isolates was studied in beef cattle and sheep at slaughter in Portugal. CTX-M-producing E. coli isolates were detected in 7% of the 127 fecal samples. The beta-lactamase genes detected were as following: CTX-M-32 (n = 4), TEM-1 + CTX-M-1 (n = 3) and CTX-M-1 (n = 2). All CTX-M-containing isolates exhibit a multiresistant phenotype. MLST analysis revealed four different STs under 2 ST complexes (STC10 and STC155) and we detected a novel allelic profile representing a new ST, registered in the database as ST2526. Five of the CTX-M containing isolates were classified in the B1 phylogroup and 4 isolates in the A phylogroup. Eight isolates harbored at least one of the virulence factors studied. Detection of CTX-M-producers E. coli in beef cattle and sheep raises important questions as they can represent a potential risk factor to public health.
- 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, PatríciaThe 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.
- Genetic Diversity and Antibiotic Resistance Among Coagulase-Negative Staphylococci Recovered from Birds of Prey in PortugalPublication . Sousa, Margarida; Silva, Nuno; Igrejas, Gilberto; Sargo, Roberto; Benito, Daniel; Gómez, Paula; Lozano, Carmen; Manageiro, Vera; Torres, Carmen; Caniça, Manuela; Poeta, PatríciaWild animal populations in contact with antimicrobials and antimicrobial resistant bacteria that are daily released into the environment are able to become unintentional hosts of these resistant microorganisms. To clarify this issue, our study evaluated the presence of antibiotic resistance determinants on coagulase-negative staphylococci recovered from birds of prey and studied their genetic relatedness by pulsed-field gel electrophoresis (PFGE). The unusual vga(A) and erm(T) genes, which confer resistance to clindamycin and erythromycin, respectively, were detected in Staphylococcus sciuri or Staphylococcus xylosus strains and the tet(K) gene in Staphylococcus kloosii. The PFGE patterns showed that three S. xylosus (isolated of Strix aluco and Otus scops) and two S. sciuri (recovered from Strix aluco and Milvus migrans) were clonally indistinguishable. These animals could be a source of unusual antimicrobial resistance determinants for highly used antibiotics in veterinary clinical practice.
- MRSA CC398 recovered from wild boar harboring new SCCmec type IV J3 variantPublication . Sousa, Margarida; Silva, Nuno; Borges, Vítor; Gomes, João P.; Vieira, Luís; Caniça, Manuela; Torres, Carmen; Igrejas, Gilberto; Poeta, PatríciaA methicillin-resistant Staphylococcus aureus CC398 was recovered from a wild female boar (Sus scrofa) in the north of Portugal, in 2013 (Sousa et al. 2017). Whole genome sequencing (WGS) revealed this strain carries a new variant of a mecA-containing staphylococcal chromosomal gene cassette (SCCmec) type IV with an uncommon J3 region. WGS studies can facilitate surveillance and provide more detailed characterization of bacterial clones circulating in the wild, reinforcing the need for a one health perspective to better understand and control antimicrobial resistance.