86 results on '"Radhouani, H."'
Search Results
2. Proteome of a methicillin-resistant Staphylococcus aureus clinical strain of sequence type ST398
- Author
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Monteiro, R., Vitorino, R., Domingues, P., Radhouani, H., Carvalho, C., Poeta, P., Torres, C., and Igrejas, G.
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- 2012
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3. Genomic and proteomic evaluation of antibiotic resistance in Salmonella strains
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Pinto, L., Poeta, P., Vieira, S., Caleja, C., Radhouani, H., Carvalho, C., Vieira-Pinto, M., Themudo, P., Torres, C., Vitorino, R., Domingues, P., and Igrejas, G.
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- 2010
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4. Fabrication of biocompatible porous SAIB/silk fibroin scaffolds using ionic liquids
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Gonçalves, C., primary, Gomes, J. M., additional, Maia, F. R., additional, Radhouani, H., additional, Silva, S. S., additional, Reis, R. L., additional, and Oliveira, J. M., additional
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- 2021
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5. Antimicrobial resistance in faecal enterococci and Escherichia coli isolates recovered from Iberian wolf
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Gonçalves, A., Igrejas, G., Radhouani, H., Correia, S., Pacheco, R., Santos, T., Monteiro, R., Guerra, A., Petrucci-Fonseca, F., Brito, F., Torres, C., and Poeta, P.
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- 2013
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6. Detection of extended-spectrum beta-lactamase-producing Escherichia coli isolates in faecal samples of Iberian lynx
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Gonçalves, A., Igrejas, G., Radhouani, H., Estepa, V., Alcaide, E., Zorrilla, I., Serra, R., Torres, C., and Poeta, P.
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- 2012
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7. MLST and a genetic study of antibiotic resistance and virulence factors in vanA-containing Enterococcus from buzzards (Buteo buteo)
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Radhouani, H., Pinto, L., Coelho, C., Sargo, R., Araújo, C., López, M., Torres, C., Igrejas, G., and Poeta, P.
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- 2010
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8. Iberian Lynx (Lynx pardinus) from the captive breeding program as reservoir of antimicrobial resistant enterococci and Escherichia coli isolates
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Gonçalves, A., Igrejas, G., Radhouani, H., Santos, T., Monteiro, R., Marinho, C., Pérez, M.J., Canales, R., Mendoza, J.L., Serra, R., Torres, C., and Poeta, P.
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biology ,Nalidixic acid ,Tetracycline ,Enterococci ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,Antimicrobial resistance ,Iberian lynx ,Biochemistry ,Enterococcus durans ,Enterococcus faecalis ,Microbiology ,Gene cassette ,Antibiotic resistance ,Enterococcus hirae ,Virulence genes ,Genetics ,medicine ,Escherichia coli ,Molecular Biology ,Enterococcus faecium ,medicine.drug - Abstract
A total of 98 faecal samples from captive specimens of Iberian lynx were collected and analysed for enterococci (96 isolates) and Escherichia coli (90 isolates) recovery. These 186 isolates were tested for antimicrobial resistance, molecular mechanisms of resistance, and detection of virulence genes. Among the enterococci, Enterococcus hirae was the most prevalent species (35 isolates), followed by Enterococcus faecalis (30 isolates), Enterococcus faecium (27 isolates), and Enterococcus durans (4 isolates). High rates of resistance to tetracycline, erythromycin and high-level-kanamycin were detected among enterococcal isolates (41%, 26%, and 19%, respectively). The tet (M) and/or tet (L), erm (B), aac (6 ′ )-Ie- aph (2 ″ )-Ia, ant (6)-Ia, or aph (3 ′ )-IIIa genes were detected among resistant enterococci. Likewise, high rates of resistance were detected in E. coli isolates to tetracycline, streptomycin, sulfamethoxazole-trimethoprim (SXT), nalidixic acid, ampicillin, and ciprofloxacin (34%, 28%, 26%, 21%, 17%, and 16%, respectively). Furthermore, the bla TEM or bla SHV , tet (A) and/or tet (B), aadA or strA - strB , aac (3)-II and/or aac (3)-IV, and different combinations of sul genes were detected among most resistant isolates. Fifteen isolates contained class 1 and/or class 2 integrons and 3 different gene cassette arrays were identified ( aadA1 , dfrA1 + aadA1 , and estX + psp + aadA2 ). The E. coli isolates were ascribed to phylo-groups A (12%); B1 (40%); B2 (37%), and D (11%), being fimA the most prevalent virulence gene (n=84), followed by aer (n=13), cnf1 (n=13), papC (n=10) and papG -allele III (n=9). This study showed specimens of Iberian lynx acting as reservoirs of resistance genes, and in future (re)introductions they could spread resistant bacteria throughout the environment.
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- 2013
9. Comparative proteomic map among vanA-containing Enterococcus isolated from yellow-legged gulls
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Radhouani, H., Poeta, P., Pinto, L., Monteiro, R., Nunes-Miranda, J., Correia, S., Vieira, S., Carvalho, C., Rodrigues, J., López, M., Torres, C., Vitorino, R., Domingues, P., and Igrejas, G.
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Proteomics ,Virulence factors ,biology ,Bioinformatics ,Computational biology ,Antimicrobial resistance ,biology.organism_classification ,Biochemistry ,Genome ,Microbiology ,Complement (complexity) ,Databases ,Antibiotic resistance ,VanA-containing Enterococcus ,Enterococcus ,Proteome ,Genetics ,Molecular Biology ,Organism - Abstract
The increase of VRE, therefore, represents an urgent threat for patient care and creates a reservoir of mobile resistance genes for other, more virulent pathogens. The existence of VRE in different ecologic niches complicates the understanding of its epidemiology. The aim of the present study was to study the proteome of 2 vanA strains recovered from seagull faecal samples. The vanA E. durans and vanA E. faecium isolates presented different genomic patterns: tet(M)-tet(L)-erm(B) and tet(M)-tet(L)-erm(B)-hyl, respectively. A total of 123 spots were excised from two-dimensional gel electrophoresis (2-DE) gel of vanA E. durans SG 2 strain, and 16 were successfully identified by using MS, representing 42 different proteins. For the vanA E. faecium SG 50 strain, 93 spots were excised from the 2-DE gel and 23 were identified, representing 47 different proteins. The vancomycin/teicoplanin A-type resistance protein vanA in vanA E. durans SG 2 strain was present in two different spots. The identified proteins have shown diverse functional activities including glycolysis, conjugation, translation, protein biosynthesis, among others. This work reports the impact of proteomics on knowledge of vanA enterococci strains and will be helpful to further understand the antibiotic-resistant mechanism.
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- 2012
10. Detection and genetic characterisation of vanA-containing enterococcus strains in healthy lusitano horses
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Moura, I., Radhouani, H., Torres, C., Poeta, P., and Igrejas, G.
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Portugal ,Antibiotic resistance ,Enterococci ,Vancomycin Resistance ,Microbial Sensitivity Tests ,Horse ,Anti-Bacterial Agents ,Feces ,Bacterial Proteins ,Vancomycin ,Animals ,Horse Diseases ,Lusitano horses ,Horses ,Teicoplanin ,Carbon-Oxygen Ligases ,Vana ,Enterococcus - Abstract
Lusitano horses were investigated in order to detect the presence of vancomycin-resistant enterococci. vanA isolates showed high level vancomycin (Minimum inhibitory concentration; MIC 128 mg/l) and teicoplanin resistance (MIC 64 mg/l), as well as resistance to ciprofloxacin, erythromycin and tetracycline. The tet(L) and erm(B) genes, associated with tetracycline and erythromycin resistance, respectively, were found in all vanA isolates.The intestinal tract of Lusitano horses can be a potential reservoir for vanA-containing enterococci. © 2009 EVJ Ltd.
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- 2010
11. Wild boars as reservoirs of extended-spectrum beta-lactamases in Escherichia coli isolates of the A, B1 and B2 phylogenetic groups
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Poeta, P., Radhouani, H., Pinto, L., Martinho, A., Rego, V., Rodrigues, R., Gonçalves, A., Rodrigues, J., Estepa, V., Torres, C., and Igrejas, G.
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Antibiotic resistance ,ESBL-producing E. coli ,β-lactamases ,Wild boars ,Phylogenetic groups - Abstract
ESBL-producing E. coli isolates have been isolated from eight of seventy seven faecal samples (10.4%) of wild boars in Portugal. The ESBL types identified by PCR and sequencing were blaCTX-M-1 (6 isolates) and blaCTX-M-1 + blaTEM1-b (2 isolates). Further resistance genes detected included tet(A) or tet(B) (in three tetracycline-resistant isolates), aadA (in three streptomycin- resistant isolates), cmlA (in one chloramphenicol-resistant isolate), sul1 and/or sul2 and/or sul3 (in all sulfonamide-resistant isolates). The intI1 gene encoding class 1 integrase was detected in all ESBL-producing E. coli isolates. One isolate also carried the intI2 gene, encoding class 2 integrase. The ESBL-producing E. coli isolates could be assigned to phylogenetic groups B1 (3 isolates), B2 (3 isolates) or A (2 isolates). Amino acid change in GyrA protein (Ser83Leu or Asp87Tyr) was detected in three nalidixic acid-resistant and ciprofloxacin-susceptible isolates. Two amino acid changes in GyrA (Ser83Leu + Asp87Asn) and one in ParC (Ser80Ile) were identified in two nalidixic acid- and ciprofloxacin-resistant isolates. As evidenced by this study wild boars could be a reservoir of antimicrobial resistance genes. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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- 2009
12. Genetic characterisation of extended-spectrum β-lactamases inEscherichia coliisolated from retail chicken products including CTX-M-9 containing isolates: a food safety risk factor
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Silva, N., primary, Costa, L., additional, Gonçalves, A., additional, Sousa, M., additional, Radhouani, H., additional, Brito, F., additional, Igrejas, G., additional, and Poeta, P., additional
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- 2012
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13. Detection of extended-spectrum beta-lactamase-producing Escherichia coli isolates in faecal samples of Iberian lynx
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Gonçalves, A., primary, Igrejas, G., additional, Radhouani, H., additional, Estepa, V., additional, Alcaide, E., additional, Zorrilla, I., additional, Serra, R., additional, Torres, C., additional, and Poeta, P., additional
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- 2011
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14. Genetic Characterization of Antibiotic Resistance in EnteropathogenicEscherichia coliCarrying Extended-Spectrum β-Lactamases Recovered from Diarrhoeic Rabbits
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Poeta, P., primary, Radhouani, H., additional, Gonçalves, A., additional, Figueiredo, N., additional, Carvalho, C., additional, Rodrigues, J., additional, and Igrejas, G., additional
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- 2010
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15. MLST and a genetic study of antibiotic resistance and virulence factors invanA-containingEnterococcus from buzzards (Buteo buteo)
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Radhouani, H., primary, Pinto, L., additional, Coelho, C., additional, Sargo, R., additional, Araújo, C., additional, López, M., additional, Torres, C., additional, Igrejas, G., additional, and Poeta, P., additional
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- 2010
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16. Detection and genetic characterisation of vanA‐containing Enterococcus strains in healthy Lusitano horses
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MOURA, I., primary, RADHOUANI, H., additional, TORRES, C., additional, POETA, P., additional, and IGREJAS, G., additional
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- 2010
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17. In vitro activity of ceftobiprole against Gram-positive and Gram-negative bacteria isolated from humans and animals
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Silva, N., primary, Radhouani, H., additional, Goncalves, A., additional, Araujo, C., additional, Rodrigues, J., additional, Igrejas, G., additional, and Poeta, P., additional
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- 2010
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18. Detection of Escherichia coli harbouring extended-spectrum -lactamases of the CTX-M classes in faecal samples of common buzzards (Buteo buteo)
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Radhouani, H., primary, Pinto, L., additional, Coelho, C., additional, Goncalves, A., additional, Sargo, R., additional, Torres, C., additional, Igrejas, G., additional, and Poeta, P., additional
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- 2009
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19. Antimicrobial resistance and phylogenetic groups in isolates of Escherichia coli from seagulls at the Berlengas nature reserve
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Radhouani, H., primary, Poeta, P., additional, Igrejas, G., additional, Gonçalves, A., additional, Vinué, L., additional, and Torres, C., additional
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- 2009
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20. Genetic characterisation of extended-spectrum β-lactamases in Escherichia coli isolated from retail chicken products including CTX-M-9 containing isolates: a food safety risk factor.
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Silva, N., Costa, L., Gonçalves, A., Sousa, M., Radhouani, H., Brito, F., Igrejas, G., and Poeta, P.
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SPECTRUM analysis ,BETA lactamases ,ESCHERICHIA coli ,FOOD safety ,POLYMERASE chain reaction ,GENE cassettes - Abstract
1. Bacterial resistance to β-lactam antibiotics has risen dramatically inEscherichia colifrom food animals. In a previous study, 29 randomly selected chicken products, collected in Portugal, were analysed for the presence of extended-spectrum β-lactamases (ESBLs)-producingE. coli; and during this study the genetic characterisation of ESBLs genes was investigated. 2. The presence of genes encoding TEM, OXA, SHV, and CTX-M type beta-lactamases was studied by PCR followed by sequencing. Additionally, other mechanisms of antimicrobial resistance, phylogenetic groups and the presence of virulence determinants were evaluated among the isolates. 3. β-lactamases genes were identified as follows:blaCTX-M-14(n = 4),blaCTX-M-1(n = 2),blaCTX-M-9(n = 4) andblaTEM-52(n = 13). Mutations at positions −42, −18, −1, and +58 ofampCpromoter region were identified in 4 non-ESBL-producing isolates. Thetet(A) ortet(B) genes were identified in all tetracycline-resistant isolates; theaadAgene detected in 8 of 10 streptomycin-resistant isolates; theaac(3)-II gene in all gentamicin-resistant isolates; thecmlAgene in the chloramphenicol-resistant isolate; andsul1and/orsul2 and/orsul3genes were found in all trimethoprim-sulfamethoxazole-resistant isolates. TheintI1gene was detected in 8 trimethoprim-sulfamethoxazole-resistant isolates and theintI2gene in 4 isolates; one gene cassette arrangements were identified among class 1 integrons (dfrA1 + aadA1) and among the class 2 integrons (dfrA1 + sat2 + aadA1). Among cefotaxime-resistant isolates, 16 belonged to A or B1 phylogenetic groups, while 11 isolates were classified into the D or B2 phylogroups. At least one virulence-associated gene (aer,fimA, orpapC) was detected in 74·1% of the cefotaxime-resistant isolates. 4. Because ESBLs-producing bacteria are resistant to a broad range of β-lactams, infections caused by these organisms complicate therapy and limit treatment options. [ABSTRACT FROM AUTHOR]
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- 2012
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21. Genetic Characterization of Antibiotic Resistance in Enteropathogenic Escherichia coli Carrying Extended-Spectrum β-Lactamases Recovered from Diarrhoeic Rabbits.
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Poeta, P., Radhouani, H., Gonçalves, A., Figueiredo, N., Carvalho, C., Rodrigues, J., and Igrejas, G.
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ESCHERICHIA coli , *STREPTOMYCIN , *GENTAMICIN , *ANTIBIOTICS , *SEROTYPING - Abstract
A total of 52 Escherichia coli strains isolated from diarrhoeic rabbits were investigated for their enteropathogenic E. coli (EPEC) pathotype by PCR amplification of eae and bfp virulence genes. A total of 22 EPEC isolates were identified, serotyped and studied for antibiotic resistance and screened for the detection of extended-spectrum β-lactamases (ESBLs). The EPEC isolates belonged to three serogroups (O26, O92 and O103). The most common serogroup (O103:K-:H2) was observed among 17 EPEC strains, the O92:K-serogroup in three isolates (the antibiotic sensitive ones) and the remaining O26:K-serogroup in two isolates (the ESBLs isolates). Resistances to ampicillin and tetracycline were the most frequent and detected followed by resistance to nalidixic acid, streptomycin, trimethoprim–sulphamethoxazole, cefoxitin, gentamicin and ciprofloxacin. All the isolates were sensitive for amikacin, ceftazidime, aztreonam, imipenem, chloramphenicol, tobramycin and amoxicillin + clavulanic acid. Two isolates recovered from two adult animals showed an intermediate susceptibility to cefotaxime, and a positive screening test for ESBL was demonstrated in both. The blaTEM gene was demonstrated in the majority of ampicillin-resistant isolates. The aac(3)-II or aac(3)-IV genes were detected in the four gentamicin-resistant isolates. In addition, the aadA gene was detected in 60% of streptomycin-resistant isolates. The tet(A) or tet(B) genes were identified in all tetracycline-resistant isolates. A total of nine EPEC isolates showed the phenotype SXT-resistant, and the sul1 and/or sul2 and/or sul3 genes were detected in all of them. Our findings showed that the molecular detection by the eae and bfp genes by PCR followed by serotyping is useful for monitoring trends in EPEC infections of rabbits allowing the identification of their possible reservoirs. The detection of genes involved in the resistance to antibiotics of different families in a relatively high proportion of faecal E. coli isolates of rabbits is of great interest and could be considered a serious public health problem. [ABSTRACT FROM AUTHOR]
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- 2010
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22. Detection of Escherichia coli harbouring extended-spectrum {beta}-lactamases of the CTX-M classes in faecal samples of common buzzards (Buteo buteo).
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Radhouani H, Pinto L, Coelho C, Gonçalves A, Sargo R, Torres C, Igrejas G, Poeta P, Radhouani, Hajer, Pinto, Luís, Coelho, Céline, Gonçalves, Alexandre, Sargo, Roberto, Torres, Carmen, Igrejas, Gilberto, and Poeta, Patrícia
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- 2010
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23. Development of Conjugated Kefiran-Chondroitin Sulphate Cryogels with Enhanced Properties for Biomedical Applications.
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Radhouani H, Gonçalves C, Maia FR, Oliveira EP, Reis RL, and Oliveira JM
- Abstract
Hydrogels based on natural polysaccharides can have unique properties and be tailored for several applications, which may be mainly limited by the fragile structure and weak mechanical properties of this type of system. We successfully prepared cryogels made of newly synthesized kefiran exopolysaccharide-chondroitin sulfate (CS) conjugate via carbodiimide-mediated coupling to overcome these drawbacks. The freeze-thawing procedure of cryogel preparation followed by lyophilization is a promising route to fabricate polymer-based scaffolds with countless and valuable biomedical applications. The novel graft macromolecular compound (kefiran-CS conjugate) was characterized through
1 H-NMR and FTIR spectroscopy-which confirmed the structure of the conjugate, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)-which mirrored good thermal stability (degradation temperature of about 215 °C) and, finally, gel permeation chromatography-size exclusion chromatography (GPC-SEC)-which proved an increased molecular weight due to chemical coupling of kefiran with CS. At the same time, the corresponding cryogels physically crosslinked after the freeze-thawing procedure were investigated by scanning electron microscopy (SEM), Micro-CT, and dynamic rheology. The results revealed a prevalent contribution of elastic/storage component to the viscoelastic behavior of cryogels in swollen state, a micromorphology with micrometer-sized open pores fully interconnected, and high porosity (ca. 90%) observed for freeze-dried cryogels. Furthermore, the metabolic activity and proliferation of human adipose stem cells (hASCs), when cultured onto the developed kefiran-CS cryogel, was maintained at a satisfactory level over 72 h. Based on the results obtained, it can be inferred that the newly freeze-dried kefiran-CS cryogels possess a host of unique properties that render them highly suitable for use in tissue engineering, regenerative medicine, drug delivery, and other biomedical applications where robust mechanical properties and biocompatibility are crucial.- Published
- 2023
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24. Impact of Kefiran Exopolysaccharide Extraction on Its Applicability for Tissue Engineering and Regenerative Medicine.
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Correia S, Gonçalves C, Oliveira JM, Radhouani H, and Reis RL
- Abstract
Kefiran is an exopolysaccharide produced by the microflora of kefir grains used to produce the fermented milk beverage kefir. The health-promoting and physicochemical properties of kefiran led to its exploration for a range of applications, mainly in the food industry and biomedical fields. Aiming to explore its potential for tissue engineering and regenerative medicine (TERM) applications, the kefiran biopolymer obtained through three different extraction methodologies was fully characterized and compared. High-quality kefiran polysaccharides were recovered with suitable yield through different extraction protocols. The methods consisted of heating the kefir grains prior to recovering kefiran by centrifugation and differed mainly in the precipitation steps included before lyophilization. Then, kefiran scaffolds were successfully produced from each extract by cryogelation and freeze-drying. In all extracts, it was possible to identify the molecular structure of the kefiran polysaccharide through
1 H-NMR and FTIR spectra. The kefiran from extraction 1 showed the highest molecular weight (~3000 kDa) and the best rheological properties, showing a pseudoplastic behavior; its scaffold presented the highest value of porosity (93.2% ± 2), and wall thickness (85.8 µm ± 16.3). All extracts showed thermal stability, good injectability and desirable viscoelastic properties; the developed scaffolds demonstrated mechanical stability, elastic behavior, and pore size comprised between 98-94 µm. Additionally, all kefiran products proved to be non-cytotoxic over L929 cells. The interesting structural, physicochemical, and biological properties showed by the kefiran extracts and cryogels revealed their biomedical potential and suitability for TERM applications.- Published
- 2022
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25. Synthesis and Characterization of Biocompatible Methacrylated Kefiran Hydrogels: Towards Tissue Engineering Applications.
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Radhouani H, Correia S, Gonçalves C, Reis RL, and Oliveira JM
- Abstract
Hydrogel application feasibility is still limited mainly due to their low mechanical strength and fragile nature. Therefore, several physical and chemical cross-linking modifications are being used to improve their properties. In this research, methacrylated Kefiran was synthesized by reacting Kefiran with methacrylic anhydride (MA). The developed MA-Kefiran was physicochemically characterized, and its biological properties evaluated by different techniques. Chemical modification of MA-Kefiran was confirmed by
1 H-NMR and FTIR and GPC-SEC showed an average Mw of 793 kDa (PDI 1.3). The mechanical data obtained revealed MA-Kefiran to be a pseudoplastic fluid with an extrusion force of 11.21 ± 2.87 N. Moreover, MA-Kefiran 3D cryogels were successfully developed and fully characterized. Through micro-CT and SEM, the scaffolds revealed high porosity (85.53 ± 0.15%) and pore size (33.67 ± 3.13 μm), thick pore walls (11.92 ± 0.44 μm) and a homogeneous structure. Finally, MA-Kefiran revealed to be biocompatible by presenting no hemolytic activity and an improved cellular function of L929 cells observed through the AlamarBlue® assay. By incorporating methacrylate groups in the Kefiran polysaccharide chain, a MA-Kefiran product was developed with remarkable physical, mechanical, and biological properties, resulting in a promising hydrogel to be used in tissue engineering and regenerative medicine applications.- Published
- 2021
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26. Biological performance of a promising Kefiran-biopolymer with potential in regenerative medicine applications: a comparative study with hyaluronic acid.
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Radhouani H, Gonçalves C, Maia FR, Oliveira JM, and Reis RL
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- Adipose Tissue cytology, Anti-Inflammatory Agents, Antioxidants, Cells, Cultured, Chelating Agents chemistry, Free Radicals, Humans, Metals, Nitrogen Oxides, Regenerative Medicine, Stem Cells, Superoxides, Biopolymers chemistry, Biopolymers pharmacology, Hyaluronic Acid chemistry, Hyaluronic Acid pharmacology, Polysaccharides chemistry
- Abstract
Kefiran from kefir grains, an exopolysaccharide (EPS) produced by lactic acid bacteria (LAB), has received an increasing interest because of its safe status. This natural biopolymer is a water-soluble glucogalactan with probed health-promoting properties. However, its biological performance has yet to be completely recognized and properly exploited. This research was carried out to evaluate the in vitro antioxidant and the in vitro anti-inflammatory properties of Kefiran biopolymer. Regarding antioxidant activity, the results demonstrated that the Kefiran extract possessed the strongest reducing power and superoxide radical scavenging, over hyaluronic acid (HA, gold standard viscosupplementation treatment). This exopolysaccharide showed a distinct antioxidant performance in the majority of in vitro working mechanisms of antioxidant activity comparing to HA. Moreover, Kefiran presented an interesting capacity to scavenge nitric oxide radical comparing to the gold standard that did not present any potency. Finally, the cytotoxic effects of Kefiran extracts on hASCs were also performed and demonstrated no cytotoxic response, ability to improve cellular function of hASCs. This study demonstrated that Kefiran represented a great scavenger for reactive oxygen and nitrogen species and showed also that it could be an excellent candidate to promote tissue repair and regeneration.
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- 2018
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27. Rapidly responsive silk fibroin hydrogels as an artificial matrix for the programmed tumor cells death.
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Ribeiro VP, Silva-Correia J, Gonçalves C, Pina S, Radhouani H, Montonen T, Hyttinen J, Roy A, Oliveira AL, Reis RL, and Oliveira JM
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- Apoptosis, Cell Line, Glioblastoma drug therapy, Glioblastoma pathology, Humans, Antineoplastic Agents therapeutic use, Fibroins therapeutic use, Hydrogels therapeutic use, Silk therapeutic use, Tumor Microenvironment drug effects
- Abstract
Timely and spatially-regulated injectable hydrogels, able to suppress growing tumors in response to conformational transitions of proteins, are of great interest in cancer research and treatment. Herein, we report rapidly responsive silk fibroin (SF) hydrogels formed by a horseradish peroxidase (HRP) crosslinking reaction at physiological conditions, and demonstrate their use as an artificial biomimetic three-dimensional (3D) matrix. The proposed SF hydrogels presented a viscoelastic nature of injectable hydrogels and spontaneous conformational changes from random coil to β-sheet conformation under physiological conditions. A human neuronal glioblastoma (U251) cell line was used for screening cell encapsulation and in vitro evaluation within the SF hydrogels. The transparent random coil SF hydrogels promoted cell viability and proliferation up to 10 days of culturing, while the crystalline SF hydrogels converted into β-sheet structure induced the formation of TUNEL-positive apoptotic cells. Therefore, this work provides a powerful tool for the investigation of the microenvironment on the programed tumor cells death, by using rapidly responsive SF hydrogels as 3D in vitro tumor models.
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- 2018
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28. Promising Biomolecules.
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Oliveira I, Carvalho AL, Radhouani H, Gonçalves C, Oliveira JM, and Reis RL
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- Animals, Biological Therapy methods, Carbohydrate Conformation, Cartilage, Articular injuries, Forecasting, Humans, Polymers chemical synthesis, Polymers therapeutic use, Polysaccharides therapeutic use, Silk therapeutic use, Therapies, Investigational, Tissue Scaffolds, Biocompatible Materials therapeutic use, Biological Factors therapeutic use, Biological Products therapeutic use, Biomimetic Materials therapeutic use, Bone Diseases therapy, Cartilage Diseases therapy, Regenerative Medicine methods, Tissue Engineering methods
- Abstract
The osteochondral defect (OD) comprises the articular cartilage and its subchondral bone. The treatment of these lesions remains as one of the most problematic clinical issues, since these defects include different tissues, requiring distinct healing approaches. Among the growing applications of regenerative medicine, clinical articular cartilage repair has been used for two decades, and it is an effective example of translational medicine; one of the most used cell-based repair strategies includes implantation of autologous cells in degradable scaffolds such as alginate, agarose, collagen, chitosan, chondroitin sulfate, cellulose, silk fibroin, hyaluronic acid, and gelatin, among others. Concerning the repair of osteochondral defects, tissue engineering and regenerative medicine started to design single- or bi-phased scaffold constructs, often containing hydroxyapatite-collagen composites, usually used as a bone substitute. Biomolecules such as natural and synthetic have been explored to recreate the cartilage-bone interface through multilayered biomimetic scaffolds. In this chapter, a succinct description about the most relevant natural and synthetic biomolecules used on cartilage and bone repair, describing the procedures to obtain these biomolecules, their chemical structure, common modifications to improve its characteristics, and also their application in the biomedical fields, is given.
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- 2018
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29. Management of knee osteoarthritis. Current status and future trends.
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Ondrésik M, Azevedo Maia FR, da Silva Morais A, Gertrudes AC, Dias Bacelar AH, Correia C, Gonçalves C, Radhouani H, Amandi Sousa R, Oliveira JM, and Reis RL
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- Biocompatible Materials, Cartilage, Articular cytology, Cartilage, Articular physiology, Genetic Therapy, Humans, Tissue Engineering, Osteoarthritis, Knee therapy
- Abstract
Osteoarthritis (OA) affects a large number of the population, and its incidence is showing a growing trend with the increasing life span. OA is the most prevalent joint condition worldwide, and currently, there is no functional cure for it. This review seeks to briefly overview the management of knee OA concerning standardized pharmaceutical and clinical approaches, as well as the new biotechnological horizons of OA treatment. The potential of biomaterials and state of the art of advanced therapeutic approaches, such as cell and gene therapy focused primarily on cartilage regeneration are the main subjects of this review. Biotechnol. Bioeng. 2017;114: 717-739. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)
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- 2017
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30. Potential impact of antimicrobial resistance in wildlife, environment and human health.
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Radhouani H, Silva N, Poeta P, Torres C, Correia S, and Igrejas G
- Abstract
Given the significant spatial and temporal heterogeneity in antimicrobial resistance distribution and the factors that affect its evolution, dissemination, and persistence, it is important to highlight that antimicrobial resistance must be viewed as an ecological problem. Monitoring the resistance prevalence of indicator bacteria such as Escherichia coli and enterococci in wild animals makes it possible to show that wildlife has the potential to serve as an environmental reservoir and melting pot of bacterial resistance. These researchers address the issue of antimicrobial-resistant microorganism proliferation in the environment and the related potential human health and environmental impact.
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- 2014
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31. Antimicrobial resistance and virulence genes in Escherichia coli and enterococci from red foxes (Vulpes vulpes).
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Radhouani H, Igrejas G, Gonçalves A, Pacheco R, Monteiro R, Sargo R, Brito F, Torres C, and Poeta P
- Subjects
- Animals, Enterococcus genetics, Enterococcus isolation & purification, Escherichia coli classification, Escherichia coli genetics, Escherichia coli isolation & purification, Feces microbiology, Genotype, Molecular Typing, Anti-Bacterial Agents pharmacology, Drug Resistance, Bacterial, Enterococcus drug effects, Escherichia coli drug effects, Foxes microbiology, Genes, Bacterial, Virulence Factors genetics
- Abstract
The aims of the study were to analyse the prevalence of antimicrobial resistance and the mechanisms implicated, as well as the virulence factors, in faecal Escherichia coli and Enterococcus spp. from red foxes. From 52 faecal samples, 22 E. coli (42.3%) and 50 enterococci (96.2%) isolates were recovered (one/sample). A high percentage of E. coli isolates exhibited resistance to streptomycin, tetracycline, trimethoprim-sulfamethoxazole or ampicillin (54-27%), and they harboured the aadA, tet(A) and/or tet(B), sul1 and blaTEM resistance genes, respectively. The E. coli isolates were ascribed to the 4 major phylogroups, D (41% of isolates), A (31.8%), B1 (18.2%) and B2 (9.1%), and carried the fimA (63.3%) or aer (13.6%) virulence genes. Among enterococcal isolates, Enterococcus faecium was the most prevalent species (50%). A high percentage of enterococcal isolates showed tetracycline resistance (88%) harbouring different combinations of tet(M) and tet(L) genes. The erm(B) or the aph(3')-IIIa gene were identified in most of our erythromycin- or kanamycin-resistant enterococci, respectively. This report suggests the role of red foxes from rural areas in the cycle of transmission and spread of antimicrobial-resistant E. coli and enterococci into the environment, representing a reservoir of these antimicrobial-resistant microorganisms., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2013
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32. Multiresistant extended-spectrum β-lactamase producing Escherichia coli in human urine samples in Portugal.
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Pacheco R, Correia S, Monteiro R, Gonçalves A, Radhouani H, Ramos S, Carvalho E, Carvalho J, Igrejas G, and Poeta P
- Subjects
- Escherichia coli genetics, Escherichia coli isolation & purification, Escherichia coli Infections epidemiology, Genotype, Humans, Microbial Sensitivity Tests, Molecular Typing, Portugal epidemiology, Urinary Tract Infections epidemiology, beta-Lactamases genetics, Drug Resistance, Multiple, Bacterial, Escherichia coli drug effects, Escherichia coli enzymology, Escherichia coli Infections microbiology, Urinary Tract Infections microbiology, Urine microbiology, beta-Lactamases metabolism
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- 2013
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33. Detection of antibiotic resistant enterococci and Escherichia coli in free range Iberian Lynx (Lynx pardinus).
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Gonçalves A, Igrejas G, Radhouani H, Santos T, Monteiro R, Pacheco R, Alcaide E, Zorrilla I, Serra R, Torres C, and Poeta P
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- Animals, Anti-Bacterial Agents pharmacology, Enterococcus drug effects, Enterococcus genetics, Enterococcus pathogenicity, Environmental Monitoring, Escherichia coli drug effects, Escherichia coli genetics, Escherichia coli pathogenicity, Feces microbiology, Genes, Bacterial, Microbial Sensitivity Tests, Polymerase Chain Reaction, Spain, Virulence, Drug Resistance, Bacterial genetics, Enterococcus isolation & purification, Escherichia coli isolation & purification, Lynx microbiology
- Abstract
Thirty fecal samples from wild specimens of Iberian lynx were collected and analyzed for Enterococcus spp. (27 isolates) and Escherichia coli (18 isolates) recovery. The 45 isolates obtained were tested for antimicrobial resistance, molecular mechanisms of resistance, and presence of virulence genes. Among the enterococci, Enterococcus faecium and Enterococcus hirae were the most prevalent species (11 isolates each), followed by Enterococcus faecalis (5 isolates). High percentages of resistance to tetracycline and erythromycin (33% and 30%, respectively) were detected among enterococcal isolates. The tet(M) and/or tet(L), erm(B), aac(6')-Ie-aph(2″)-Ia, ant(6)-Ia, or aph(3')-IIIa genes were detected among resistant enterococci. Virulence genes were detected in one E. faecalis isolate (cpd, cylB, and cylL) and one E. hirae isolate (cylL). High percentages of resistance were detected in E. coli isolates to tetracycline (33%), streptomycin (28%), nalidixic acid (28%), and sulfamethoxazole-trimethoprim (SXT, 22%). Additionally, the blaTEM, tet(A), aadA, cmlA, and different combinations of sul genes were detected among most ampicillin, tetracycline, streptomycin, chloramphenicol and SXT-resistant isolates, respectively. Two isolates contained a class 1 integron with the gene cassette arrays dfrA1 + aadA1 and dfrA12 + aadA2. The E. coli isolates were ascribed to phylo-groups A (n=5); B1 (n=4); B2 (n=6), and D (n=3), with the virulence gene fimA present in all E. coli isolates. This study found resistance genes in wild specimens of Iberian lynx. Thus, it is important to notice that multiresistant bacteria have reached species as rare and completely non-synanthropic as the Iberian lynx. Furthermore, the susceptibility of this endangered species to bacterial infection may be affected by the presence of these virulence and resistance genes., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2013
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34. Molecular characterization of extended-spectrum-beta-lactamase-producing Escherichia coli isolates from red foxes in Portugal.
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Radhouani H, Igrejas G, Gonçalves A, Estepa V, Sargo R, Torres C, and Poeta P
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Bacterial Typing Techniques, Cephalosporins pharmacology, Electrophoresis, Gel, Pulsed-Field, Escherichia coli enzymology, Escherichia coli genetics, Escherichia coli isolation & purification, Feces microbiology, Integrons, Microbial Sensitivity Tests, Multilocus Sequence Typing, Phylogeny, Portugal, Promoter Regions, Genetic, Cephalosporin Resistance, Escherichia coli classification, Foxes microbiology, beta-Lactamases genetics
- Abstract
The presence of broad-spectrum-cephalosporin-resistant Escherichia coli isolates and the implicated mechanisms of resistance and virulence factor genes were investigated in red fox (Vulpes vulpes) in Portugal. Cefotaxime-resistant E. coli isolates were isolated from two of 52 fecal samples (4 %), being both ESBL producers. The β-lactamase genes found in the two isolates were bla(SHV-12) + bla(TEM-1b). The tet(A) and sul2 genes were also detected in these isolates, together with the non-classical class 1 integron (intI1-dfrA12-orfF-aadA2-cmlA1-aadA1-qacH-IS440-sul3) with the PcH1 promoter. The two isolates belonged to the phylogroup A. Amino acid changes in GyrA (S83L + D87G) and ParC (S80I) proteins were identified in our study. Concerning MLST typing, both isolates were assigned to ST1086, never found before in wild animals, and they presented closely related PFGE patterns. This study reveals the presence of ESBL-producing E. coli isolates, in a wild ecosystem, which could be disseminated through the environment to other niches.
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- 2013
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35. High prevalence of ESBL-producing Escherichia coli isolates among hemodialysis patients in Portugal: appearance of ST410 with the bla(CTX-M-14) gene.
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Correia S, Pacheco R, Radhouani H, Diniz JC, Ponce P, Jones-Dias D, Caniça M, Igrejas G, and Poeta P
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- DNA, Bacterial genetics, Escherichia coli drug effects, Escherichia coli genetics, Feces microbiology, Humans, Microbial Sensitivity Tests, Portugal epidemiology, Prevalence, Virulence Factors genetics, beta-Lactam Resistance, beta-Lactamases genetics, Escherichia coli enzymology, Escherichia coli isolation & purification, Escherichia coli Infections epidemiology, Escherichia coli Infections microbiology, Renal Dialysis, beta-Lactamases metabolism
- Abstract
Ten extended-spectrum β-lactamase-producing Escherichia coli isolates were detected among 121 fecal samples (8.3%) recovered from hemodialysis patients in Portugal. The isolates harbored the bla(CTX-M-15), bla(CTX-M-14a), and/or bla(CTX-M-1) genes. A new sequence type, ST2229, was detected, and this study also reports, for the first time, ST410 CTX-M-14-producing isolates., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
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36. After genomics, what proteomics tools could help us understand the antimicrobial resistance of Escherichia coli?
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Radhouani H, Pinto L, Poeta P, and Igrejas G
- Subjects
- Anti-Bacterial Agents therapeutic use, Biomarkers analysis, Biomarkers metabolism, Comprehension, Escherichia coli drug effects, Escherichia coli genetics, Escherichia coli Infections drug therapy, Escherichia coli Infections genetics, Escherichia coli Infections metabolism, Humans, Microbial Sensitivity Tests methods, Proteomics trends, Drug Resistance, Microbial genetics, Drug Resistance, Microbial physiology, Escherichia coli metabolism, Genomics methods, Proteomics methods
- Abstract
Proteomic approaches have been considerably improved during the past decade and have been used to investigate the differences in protein expression profiles of cells grown under a broad spectrum of growth conditions and with different stress factors including antibiotics. In Europe, the most significant disease threat remains the presence of microorganisms that have become resistant to antimicrobials and so it is important that different scientific tools are combined to achieve the largest amount of knowledge in this area of expertise. The emergence and spread of the antibiotic-resistant Gram-negative pathogens, such as Escherichia coli, can lead to serious problem public health in humans. E. coli, a very well described prokaryote, has served as a model organism for several biological and biotechnological studies increasingly so since the completion of the E. coli genome-sequencing project. The purpose of this review is to present an overview of the different proteomic approaches to antimicrobial-resistant E. coli that will be helpful to obtain a better knowledge of the antibiotic-resistant mechanism(s). This can also aid to understand the molecular determinants involved with pathogenesis, which is essential for the development of effective strategies to combat infection and to reveal new therapeutic targets. This article is part of a Special Issue entitled: Proteomics: The clinical link., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2012
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37. Wild birds as biological indicators of environmental pollution: antimicrobial resistance patterns of Escherichia coli and enterococci isolated from common buzzards (Buteo buteo).
- Author
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Radhouani H, Poeta P, Gonçalves A, Pacheco R, Sargo R, and Igrejas G
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Cluster Analysis, Enterococcus genetics, Enterococcus isolation & purification, Escherichia coli genetics, Escherichia coli isolation & purification, Feces microbiology, Genes, Bacterial, Genotype, Humans, Molecular Typing, Phylogeny, Virulence Factors genetics, Drug Resistance, Bacterial, Enterococcus drug effects, Environmental Pollution, Escherichia coli drug effects, Falconiformes microbiology
- Abstract
A total of 36 Escherichia coli and 31 enterococci isolates were recovered from 42 common buzzard faecal samples. The E. coli isolates showed high levels of resistance to streptomycin and tetracycline. The following resistance genes were detected: bla(TEM) (20 of 22 ampicillin-resistant isolates), tet(A) and/or tet(B) (16 of 27 tetracycline-resistant isolates), aadA1 (eight of 27 streptomycin-resistant isolates), cmlA (three of 15 chloramphenicol-resistant isolates), aac(3)-II with/without aac(3)-IV (all seven gentamicin-resistant isolates) and sul1 and/or sul2 and/or sul3 [all eight sulfamethoxazole/trimethoprim-resistant (SXT) isolates]. intI1 and intI2 genes were detected in four SXT-resistant isolates. The virulence-associated genes fimA (type 1 fimbriae), papC (P fimbriae) and aer (aerobactin) were detected in 61.1, 13.8 and 11.1% of the isolates, respectively. The isolates belonged to phylogroups A (47.2%), B1 (8.3%), B2 (13.9%) and D (30.5%). For the enterococci isolates, Enterococcus faecium was the most prevalent species (48.4%). High levels of tetracycline and erythromycin resistance were found among our isolates (87 and 81%, respectively). Most of the tetracycline-resistant strains carried the tet(M) and/or tet(L) genes. The erm(B) gene was detected in 80% of erythromycin-resistant isolates. The vat(D) and/or vat(E) genes were found in nine of the 17 quinupristin-dalfopristin-resistant isolates. The enterococcal isolates showing high-level resistance for kanamycin, gentamicin and streptomycin contained the aph(3')-IIIa, aac(6')-aph(2″) and ant(6)-Ia genes, respectively. This report reveals that common buzzards seem to represent an important reservoir, or at least a source, of multi-resistant E. coli and enterococci isolates, and consequently may represent a considerable hazard to human and animal health by transmission of these isolates to waterways and other environmental sources via their faecal deposits.
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- 2012
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38. Iberian wolf as a reservoir of extended-spectrum β-lactamase-producing Escherichia coli of the TEM, SHV, and CTX-M groups.
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Gonçalves A, Igrejas G, Radhouani H, Estepa V, Pacheco R, Monteiro R, Brito F, Guerra A, Petrucci-Fonseca F, Torres C, and Poeta P
- Subjects
- Animals, DNA, Bacterial genetics, Drug Resistance, Bacterial genetics, Electrophoresis, Gel, Pulsed-Field, Escherichia coli genetics, Escherichia coli isolation & purification, Escherichia coli Infections microbiology, Escherichia coli Proteins genetics, Escherichia coli Proteins metabolism, Feces microbiology, Integrons, Microbial Sensitivity Tests, Phylogeny, Portugal, Virulence Factors genetics, beta-Lactamases classification, beta-Lactamases genetics, Anti-Bacterial Agents pharmacology, Escherichia coli drug effects, Escherichia coli enzymology, Escherichia coli Infections veterinary, Wolves microbiology, beta-Lactamases metabolism
- Abstract
The intensive use of antibiotics in human and veterinary medicine, associated with mechanisms of bacterial genetic transfer, caused a selective pressure that contributed to the dissemination of antimicrobial resistance in different bacteria groups and throughout different ecosystems. Iberian wolf, due to his predatory and wild nature, may serve as an important indicator of environmental contamination with antimicrobial resistant bacteria. The aim of this study was to characterize the diversity of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates within the fecal microbiota of Iberian wolf. Additionally, the identification of other associated resistance genes, phylogenetic groups, and the detection of virulence determinants were also focused on in this study. From 2008 to 2009, 237 fecal samples from Iberian wolf were collected in Portugal. E. coli isolates with TEM-52, SHV-12, CTX-M-1, and CTX-M-14-type ESBLs were detected in 13 of these samples (5.5%). This study reveals the presence of ESBL-producing E. coli isolates, in a wild ecosystem, which could be disseminated through the environment. Moreover, the presence of resistant genes in integrons and the existence of virulence determinants were shown. The association between antibiotic resistance and virulence determinants should be monitored, as it constitutes a serious public health problem.
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- 2012
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39. Detection of vanA-containing Enterococcus species in faecal microbiota of gilthead seabream (Sparus aurata).
- Author
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Barros J, Andrade M, Radhouani H, López M, Igrejas G, Poeta P, and Torres C
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Ecosystem, Enterococcus drug effects, Enterococcus enzymology, Enterococcus faecalis drug effects, Enterococcus faecalis enzymology, Enterococcus faecalis genetics, Enterococcus faecalis isolation & purification, Enterococcus faecium drug effects, Enterococcus faecium enzymology, Enterococcus faecium genetics, Enterococcus faecium isolation & purification, Microbial Sensitivity Tests, Multilocus Sequence Typing, Portugal, Vancomycin pharmacology, Bacterial Proteins genetics, Carbon-Oxygen Ligases genetics, Enterococcus genetics, Enterococcus isolation & purification, Feces microbiology, Sea Bream microbiology, Vancomycin Resistance genetics
- Abstract
Vancomycin-resistant Enterococcus faecalis, E. faecium and E. durans isolates with the genotype vanA were detected in 7 of 118 faecal samples (5.9%) of natural gilthead seabream recovered off the coast of Portugal, and one vancomycin-resistant isolate/sample was further characterized. The genes erm(B), tet(L), tet(M), aac(6')-aph(2"), aph(3')-IIIa and/or ant(6)-Ia were identified in most of the 7 vancomycin-resistant enterococci. Sequence types ST273, ST313 and ST76 were detected in three E. faecium isolates and ST6 in two E. faecalis isolates. VanA-containing enterococci are suggested to be disseminated in fish in marine ecosystems close to areas of human activity.
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- 2012
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40. Detection of vancomycin-resistant enterococci from faecal samples of Iberian wolf and Iberian lynx, including Enterococcus faecium strains of CC17 and the new singleton ST573.
- Author
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Gonçalves A, Igrejas G, Radhouani H, López M, Guerra A, Petrucci-Fonseca F, Alcaide E, Zorrilla I, Serra R, Torres C, and Poeta P
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Enterococcus drug effects, Enterococcus faecium drug effects, Enterococcus faecium genetics, Enterococcus faecium isolation & purification, Feces microbiology, Multilocus Sequence Typing, Portugal, Spain, Vancomycin pharmacology, Bacterial Proteins genetics, Enterococcus genetics, Enterococcus isolation & purification, Lynx microbiology, Vancomycin Resistance, Virulence Factors genetics, Wolves microbiology
- Abstract
The aim of this study was to perform the molecular characterization of vancomycin resistant enterococci (VRE) within the faecal flora of Iberian wolf and Iberian lynx. The association with other resistance genes and the detection of virulence genes were also analysed. From 2008 to 2010, 365 faecal samples from Iberian wolf and Iberian lynx were collected and tested for VRE recovery. Mechanisms of resistance to vancomycin and other antibiotics, as well as genes encoding virulence factors were detected through PCR. Multilocus Sequence Typing (MLST) was performed for Enterococcus faecium strains. VRE were recovered in 8 of the 365 analysed samples. The vanA gene was identified in two E. faecium isolates recovered from Iberian wolf faecal samples and the remaining six showed intrinsic resistance (3 vanC1-E. gallinarum and 3 vanC2-E. casseliflavus, from Iberian wolf and Iberian lynx faecal samples, respectively). One vanA-containing isolate showed tetracycline and erythromycin resistance [with erm(B) and tet(L) genes] and the other one also exhibited ampicillin and kanamycin resistance [with erm(B), tet(M) and aph(3')-III genes]. One of the vanA-isolates revealed a new sequence type named ST573 and the other one belonged to the CC17 clonal complex (ST18). The hyl gene was detected in one E. casseliflavus and three E. gallinarum but not among vanA-positive isolates, and the occurrence of cylA and cylL genes was confirmed in two E. casseliflavus isolates. A low prevalence of VRE has been detected in faecal samples of Iberian wolf and Iberian lynx and strains with an acquired mechanism of resistance to vancomycin have not been detected among Iberian lynx., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2011
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41. Genetic detection and multilocus sequence typing of vanA-containing Enterococcus strains from mullets fish (Liza ramada).
- Author
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Araújo C, Torres C, Gonçalves A, Carneiro C, López M, Radhouani H, Pardal M, Igrejas G, and Poeta P
- Subjects
- Animals, Enterococcus faecium isolation & purification, Feces microbiology, Glycopeptides genetics, Microbial Sensitivity Tests methods, Multilocus Sequence Typing methods, Virulence Factors genetics, Bacterial Proteins genetics, Carbon-Oxygen Ligases genetics, Enterococcus faecium drug effects, Enterococcus faecium genetics, Smegmamorpha microbiology, Vancomycin pharmacology, Vancomycin Resistance genetics
- Abstract
Enterococci have emerged as important nosocomial and community-acquired pathogens in humans. The presence of vanA-enterococci was investigated in 103 fecal samples recovered from mullets fish (Liza ramada). All fecal samples were inoculated in Slanetz-Bartley agar plates supplemented with 4 mg/L of vancomycin for vancomycin-resistant enterococci (VRE) recovery and two isolates/sample were characterized. Antibiotic susceptibility was tested for 11 antibiotics by disk diffusion and agar dilution methods. VRE identification was performed by biochemical and molecular methods. Additionally, the mechanisms of resistance to glycopeptides (vanA, vanB, vanC1, vanC2, and vanD) and other antibiotics [erm(A), erm(B), tet(L), tet(M), aph(2'')-aac(6'), aph(3')-IIIa, ant(6'), vat(D), vat(E)] as well as the presence of enterococcal surface protein (esp) and hyl virulence factors were investigated. vanA-Enterococcus faecium isolates were recovered from 4 of 103 tested samples, and they showed glycopeptide and erythromycin resistances. Three of them were also ampicillin resistant, two showed resistance to tetracycline, ciprofloxacin, and kanamycin, and one showed resistance to gentamicin. The tet(M) and erm(B) genes were found in all tetracycline- and erythromycin-resistant strains, respectively. The aph(3')-III and aph(2'')-aac(6') genes were identified in the kanamycin- and gentamicin-resistant isolates, respectively. The IS1216 element was identified within vanX-vanY region of Tn1546 in two vanA isolates. The hyl and esp virulence genes were found in four and two isolates, respectively. vanA-strains were ascribed to sequence types ST280 (two isolates) and ST273 (two isolates), including both lineages into the clonal complex CC17. Mullets fish can excrete VRE in their feces and may be a reservoir for such resistant bacteria that can be transmitted to other animals including humans.
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- 2011
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42. Molecular characterization of antibiotic resistance in enterococci recovered from seagulls (Larus cachinnans) representing an environmental health problem.
- Author
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Radhouani H, Igrejas G, Pinto L, Gonçalves A, Coelho C, Rodrigues J, and Poeta P
- Subjects
- Animals, Enterococcus drug effects, Genes, Bacterial, Phenotype, Tetracycline Resistance, Anti-Bacterial Agents pharmacology, Charadriiformes microbiology, Drug Resistance, Bacterial, Enterococcus genetics, Enterococcus isolation & purification, Feces microbiology
- Abstract
Antimicrobial resistance and the mechanisms implicated were studied in 54 enterococci recovered from 57 seagull fecal samples. Almost 78% of the recovered enterococci showed resistance against one or more antibiotics and these isolates were identified to the species level. E. faecium was the most prevalent species (52.4%). High percentages of erythromycin and tetracycline resistances were found among our isolates (95.2%), and lower percentages were identified to other antibiotics. Most of the tetracycline-resistant strains carried the tet(M) and/or tet(L) genes. Genes associated with Tn916/Tn1545 and/or Tn5397 transposons were detected in 45% of tetracycline-resistant isolates. The erm(B) gene was detected in 65% of erythromycin-resistant isolates. The vat(D) and vat(E) genes were present in 5.9% and 11.8% of quinupristin/dalfopristin-resistant isolates, respectively. The ant(6)-Ia gene was identified in 57.1% of streptomycin-resistant isolates. All nine kanamycin-resistant isolates carried the aph(3)'-IIIa gene. The cat(A) gene was found in two chloramphenicol-resistant isolates. Seagulls should be considered a risk species for spreading in the environment antimicrobial resistant enterococci and can serve as a sentinel for antibiotic pressure from the surrounding farm and urban setting.
- Published
- 2011
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43. Clonal lineages, antibiotic resistance and virulence factors in vancomycin-resistant enterococci isolated from fecal samples of red foxes (Vulpes vulpes).
- Author
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Radhouani H, Igrejas G, Carvalho C, Pinto L, Gonçalves A, Lopez M, Sargo R, Cardoso L, Martinho A, Rego V, Rodrigues R, Torres C, and Poeta P
- Subjects
- Animals, Animals, Wild, Enterococcus genetics, Enterococcus pathogenicity, Feces microbiology, Female, Incidence, Male, Microbial Sensitivity Tests veterinary, Portugal epidemiology, Virulence Factors genetics, Anti-Bacterial Agents pharmacology, Enterococcus drug effects, Foxes microbiology, Vancomycin pharmacology, Vancomycin Resistance
- Abstract
Fourteen vanA-containing enterococcal isolates were detected in seven of 52 fecal samples (13.5%) from free-ranging red foxes in Portugal. Nine of the vanA-containing isolates were Enterococcus faecium and five were E. durans. Both sequence types, ST262 and ST273, were identified among E. faecium isolates.
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- 2011
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44. Molecular detection and characterization of methicillin-resistant Staphylococcus aureus (MRSA) isolates from dogs in Portugal.
- Author
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Coelho C, Torres C, Radhouani H, Pinto L, Lozano C, Gómez-Sanz E, Zaragaza M, Igrejas G, and Poeta P
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Antigens, Bacterial genetics, Antigens, Bacterial metabolism, Bacterial Toxins genetics, Bacterial Toxins metabolism, Bacterial Typing Techniques, Carrier State epidemiology, Carrier State transmission, Chromosomes, Bacterial chemistry, Chromosomes, Bacterial genetics, DNA Gyrase genetics, DNA Gyrase metabolism, Dogs, Exotoxins genetics, Exotoxins metabolism, Leukocidins genetics, Leukocidins metabolism, Methicillin Resistance drug effects, Methicillin-Resistant Staphylococcus aureus classification, Methicillin-Resistant Staphylococcus aureus drug effects, Methicillin-Resistant Staphylococcus aureus isolation & purification, Microbial Sensitivity Tests, Multilocus Sequence Typing, Mutation, Polymerase Chain Reaction, Portugal, Sequence Analysis, DNA, Staphylococcal Infections epidemiology, Staphylococcal Infections transmission, Carrier State microbiology, Carrier State veterinary, Methicillin Resistance genetics, Methicillin-Resistant Staphylococcus aureus genetics, Nasal Cavity microbiology, Staphylococcal Infections microbiology, Staphylococcal Infections veterinary
- Abstract
Fifty-four healthy dogs were screened in Portugal for the presence of nasal methicillin-resistant Staphylococcus aureus (MRSA) carriage. Sixteen MRSA isolates (one/sample) were recovered from nasal samples of dogs, and they were typed by molecular methods (S. aureus protein A [spa]-, multilocus sequence typing-, staphylococcal cassette chromosome mec-typing). MRSA isolates were investigated for their susceptibility to antimicrobial agents by disk-diffusion test. The presence of resistance genes and of the Panton-Valentine leukocidin gene (lukF-lukS) was analyzed by PCR. Four different spa-types were identified among our MRSA isolates (t032, t432, t747, and t4726), with t032 as the most frequently detected. The sequence-type ST22 was identified in four tested MRSA isolates with different spa-types. All 16 isolates presented the staphylococcal cassette chromosome mec type IV. Most of MRSA isolates were resistant to ciprofloxacin, erythromycin, and clindamycin (94%-100%), and no resistance was identified to chloramphenicol, mupirocin, and trimethoprim-sulfametoxazole. The ermC and tetM resistance genes were detected in all MRSA isolates. The amino acid changes Ser84Leu in GyrA protein and Ser80Phe in GrlA protein were the most prevalent ones in our MRSA isolates. None of the MRSA strains carried the lukF-lukS genes. The results presented in this study indicate that healthy dogs may be a reservoir of MRSA that could be transmitted to humans by direct contact.
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- 2011
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45. Gilthead seabream (Sparus aurata) carrying antibiotic resistant enterococci. A potential bioindicator of marine contamination?
- Author
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Barros J, Igrejas G, Andrade M, Radhouani H, López M, Torres C, and Poeta P
- Subjects
- Animals, Enterococcus isolation & purification, Enterococcus physiology, Humans, Seawater microbiology, Water Pollution, Chemical statistics & numerical data, Drug Resistance, Bacterial genetics, Enterococcus genetics, Environmental Monitoring methods, Sea Bream microbiology, Seawater chemistry
- Abstract
Antibiotic resistance in bacteria is a growing problem that is not only restricted to the clinical setting but also to other environments such as marine species that harbor antibiotic resistant bacteria and therefore may serve as reservoirs for antibiotic-resistance genetic determinants. The aim of this study was to evaluate antibiotic resistance phenotypes in enterococci isolated from fecal samples of gilthead seabream and the associated mechanisms of resistance. A collection of 118 samples were analyzed and 73 enterococci were recovered. The strains showed high percentages of resistance to erythromycin and tetracycline (58.9% and 17.8%, respectively). Lower level of resistance (<13%) was detected for quinupristin-dalfopristin, ampicillin, high-level-gentamicin, high-level-streptomycin, high-level-kanamycin, ciprofloxacin and chloramphenicol. The erm(B), tet(L) or tet(M), aac(6')-aph(2″) and aph(3')-IIIa genes were shown in isolates resistant to erythromycin, tetracycline, high-level gentamicin and high-level kanamycin, respectively. Antibiotic resistance in natural microbiota is becoming a concern of human and environmental health., (Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2011
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46. Vancomycin-resistant enterococci from Portuguese wastewater treatment plants.
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Araújo C, Torres C, Silva N, Carneiro C, Gonçalves A, Radhouani H, Correia S, da Costa PM, Paccheco R, Zarazaga M, Ruiz-Larrea F, Poeta P, and Igrejas G
- Subjects
- Animals, Enterococcus classification, Genes, Bacterial, Humans, Microbial Sensitivity Tests, Polymerase Chain Reaction, Portugal, Water Purification, Anti-Bacterial Agents pharmacology, Enterococcus drug effects, Enterococcus isolation & purification, Sewage microbiology, Vancomycin pharmacology, Vancomycin Resistance
- Abstract
The objective of this study was to evaluate the incidence of vancomycin resistant enterococci in sludge and sewage of urban and poultry-slaughterhouse wastewater treatment plants. A total of 17 vancomycin resistant enterococci (eight vanA -containing Enterococcus faecium and nine vanC1/vanC2 -containing Enterococcus gallinarum/casseliflavus) were found among 499 isolates of sewage and sludge samples of 14 urban and nine poultry-slaughterhouse wastewater treatment plants. These seventeen VRE isolates showed resistance to kanamycin (n = 8), tetracycline (n = 7), erythromycin (n = 7), ciprofloxacin (n = 7), ampicillin (n = 7), streptomycin (n = 6), and gentamicin (n = 2). The tetM gene, related with tetracycline resistance, was found in six of eight van A-containing isolates, in all seven vanC-1 isolates and in one of two vanC-2 isolates. The ermB gene in seven erythromycin-resistant isolates; and the aac6 '-aph2 ″ gene in the two high-level-gentamicin-resistant isolates. Moreover, two vanA -containing E. faecium isolates harbored the hyl virulence gene, and three isolates the entA bacteriocin gene. The purK-1 allele was detected in our urban vanA -containing E. faecium isolate, and we found as well the purK-6 allele in one poultry-slaughterhouse vanA -containing E. faecium isolate. This study suggests that the wastewater treatment plants might be an important source of dissemination of antibiotic-resistant enterococci in Portugal., (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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- 2010
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47. Genetic characterization of extended-spectrum beta-lactamases in Escherichia coli isolates of pigs from a Portuguese intensive swine farm.
- Author
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Gonçalves A, Torres C, Silva N, Carneiro C, Radhouani H, Coelho C, Araújo C, Rodrigues J, Vinué L, Somalo S, Poeta P, and Igrejas G
- Subjects
- Animals, Electrophoresis, Gel, Pulsed-Field, Escherichia coli drug effects, Escherichia coli growth & development, Escherichia coli isolation & purification, Feces microbiology, Genes, MDR, Genetic Markers, Microbial Sensitivity Tests, Plasmids genetics, Polymerase Chain Reaction, Portugal, Drug Resistance, Bacterial, Escherichia coli enzymology, Escherichia coli Proteins genetics, Swine microbiology, beta-Lactamases genetics
- Abstract
There is a great concern by the emergence and the wide dissemination of extended-spectrum beta-lactamases (ESBLs) among animal Escherichia coli isolates. We intended to determinate the carriage level and type of ESBLs in E. coli obtained from fecal samples from pigs raised on an intensive pig farm in Portugal; further to characterize other associated resistance genes and their plasmid content, the phylogenetic groups, and the clonal relationship of ESBL-positive isolates. Sixty-five fecal samples were seeded in Levine media supplemented with cefotaxime for E. coli recovery. Susceptibility to 16 antimicrobial agents was performed by disk diffusion agar. ESBL-phenotypic detection was carried out by double-disk test; and the presence of the genes encoding TEM, OXA, SHV, and CTX-M type beta-lactamases was studied by polymerase chain reaction and sequencing. Other mechanisms of antimicrobial resistance and phylogenetic groups were also determined. Clonal relationship was performed by pulsed-field gel electrophoresis. ESBL-producing E. coli isolates were detected in 16 fecal samples, and one isolate per sample was studied. The CTX-M-1 type ESBL was detected in the 16 isolates. The gene encoding TEM-1 was identified to be associated with eight CTX-M-1-positive isolates. The tet(A) gene was found in 12 of 14 tetracycline-resistant isolates, and the aadA or strA-strB genes were found in the streptomycin-resistant isolates. Fourteen and two ESBL-containing isolates belonged to A and B1 phylogenetic groups, respectively. Clonal relationship of ESBL-containing isolates identified seven unrelated patterns. Swine represent an important reservoir of ESBL-containing E. coli isolates, especially of the CTX-M-1 type.
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- 2010
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48. Antimicrobial activity of doripenem against bacterial isolates from humans and animals.
- Author
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Igrejas G, Silva N, Radhouani H, Gonçalves A, Araújo C, Rodrigues J, and Poeta P
- Subjects
- Animals, Doripenem, Enterococcus faecalis isolation & purification, Enterococcus faecium isolation & purification, Escherichia coli isolation & purification, Humans, Microbial Sensitivity Tests, Portugal, Anti-Bacterial Agents pharmacology, Carbapenems pharmacology, Enterococcus faecalis drug effects, Enterococcus faecium drug effects, Escherichia coli drug effects
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- 2010
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49. Proteomic characterization of vanA-containing Enterococcus recovered from Seagulls at the Berlengas Natural Reserve, W Portugal.
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Radhouani H, Poeta P, Pinto L, Miranda J, Coelho C, Carvalho C, Rodrigues J, López M, Torres C, Vitorino R, Domingues P, and Igrejas G
- Abstract
Background: Enterococci have emerged as the third most common cause of nosocomial infections, requiring bactericidal antimicrobial therapy. Although vancomycin resistance is a major problem in clinics and has emerged in an important extend in farm animals, few studies have examined it in wild animals. To determine the prevalence of vanA-containing Enterococcus strains among faecal samples of Seagulls (Larus cachinnans) of Berlengas Natural Reserve of Portugal, we developed a proteomic approach integrated with genomic data. The purpose was to detect the maximum number of proteins that vary in different enterococci species which are thought to be connected in some, as yet unknown, way to antibiotic resistance., Results: From the 57 seagull samples, 54 faecal samples showed the presence of Enterococcus isolates (94.7%). For the enterococci, E. faecium was the most prevalent species in seagulls (50%), followed by E. faecalis and E. durans (10.4%), and E. hirae (6.3%). VanA-containing enterococcal strains were detected in 10.5% of the 57 seagull faecal samples studied. Four of the vanA-containing enterococci were identified as E. faecium and two as E. durans. The tet(M) gene was found in all five tetracycline-resistant vanA strains. The erm(B) gene was demonstrated in all six erythromycin-resistant vanA strains. The hyl virulence gene was detected in all four vanA-containing E. faecium isolates in this study, and two of them harboured the purK1 allele. In addition these strains also showed ampicillin and ciprofoxacin resistance. The whole-cell proteomic profile of vanA-containing Enterococcus strains was applied to evaluate the discriminatory power of this technique for their identification. The major differences among species-specific profiles were found in the positions corresponding to 97-45 kDa. Sixty individualized protein spots for each vanA isolate was identified and suitable for peptide mass fingerprinting measures by spectrometry measuring (MALDI/TOF MS) and their identification through bioinformatic databases query. The proteins were classified in different groups according to their biological function: protein biosynthesis, ATP synthesis, glycolysis, conjugation and antibiotic resistance. Taking into account the origin of these strains and its relation to infectious processes in humans and animals, it is important to explore the proteome of new strains which might serve as protein biomarkers for biological activity., Conclusions: The comprehensive description of proteins isolated from vancomycin-resistant Enterococcus faecium and E. durans may provide new targets for development of antimicrobial agents. This knowledge may help to identify new biomarkers of antibiotic resistance and virulence factors.
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- 2010
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50. Molecular characterization of antimicrobial resistance in enterococci and Escherichia coli isolates from European wild rabbit (Oryctolagus cuniculus).
- Author
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Silva N, Igrejas G, Figueiredo N, Gonçalves A, Radhouani H, Rodrigues J, and Poeta P
- Subjects
- Animals, Enterococcus drug effects, Enterococcus isolation & purification, Escherichia coli drug effects, Escherichia coli isolation & purification, Feces microbiology, Genes, Bacterial, Microbial Sensitivity Tests, Portugal, Rabbits, Drug Resistance, Bacterial genetics, Enterococcus genetics, Environmental Monitoring, Escherichia coli genetics
- Abstract
A total of 44 Escherichia coli and 64 enterococci recovered from 77 intestinal samples of wild European rabbits in Portugal were analyzed for resistance to antimicrobial agents. Resistance in E. coli isolates was observed for ampicillin, tetracycline, sulfamethoxazole/trimethoprim, streptomycin, gentamicin, tobramycin, nalidixic acid, ciprofloxacin and chloramphenicol. None of the E. coli isolates produced extended-spectrum beta-lactamases (ESBLs). The bla(TEM), aadA, aac(3)-II, tet(A) and/or tet(B), and the catA genes were demonstrated in all ampicillin, streptomycin, gentamicin, tetracycline, and chloramphenicol-resistant isolates respectively, and the sul1 and/or sul2 and/or sul3 genes in 4 of 5 sulfamethoxazole/trimethoprim resistant isolates. Of the enterococcal isolates, Enterococcus faecalis was the most prevalent detected species (39 isolates), followed by E. faecium (21 isolates) and E. hirae (4 isolates). More than one-fourth (29.7%) of the isolates were resistant to tetracycline; 20.3% were resistant to erythromycin, 14.1% were resistant to ciprofloxacin and 10.9% were resistant to high-level-kanamycin. Lower level of resistance (<10%) was detected for ampicillin, quinupristin/dalfopristin and high-level-gentamicin, -streptomycin. No vancomycin-resistance was detected in the enterococci isolates. Resistance genes detected included aac(6')-aph(2''), ant(6)-Ia, tet(M) and/or tet(L) in all gentamicin, streptomycin and tetracycline-resistant isolates respectively. The aph(3')-IIIa gene was detected in 6 of 7 kanamycin-resistant isolates, the erm(B) gene in 11 of 13 erythromycin-resistant isolates and the vat(D) gene in the quinupristin/dalfopristin-resistant E. faecium isolate. This survey showed that faecal bacteria such as E. coli and enterococci of wild rabbits could be a reservoir of antimicrobial resistance genes., (Copyright 2010 Elsevier B.V. All rights reserved.)
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- 2010
- Full Text
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