Thymbra capitata essential oil has a significant antimicrobial activity against methicillin-resistant Staphylococcus aureus pre-formed biofilms.

Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant opportunistic pathogen with a great ability to form biofilms. Herein, the antimicrobial potential of Thymbra capitata essential oil (EO) against MRSA biofilms was investigated. The determination of the minimum inhibitory concentration (MIC) and the minimum lethal concentration (MLC) of the T. capitata EO was first investigated on a group of clinical isolates from septicaemias, diabetic foot ulcers and osteomyelitis. Biofilms were incubated with the EO at the MLC and its anti-biofilm potential was investigated. A strong antimicrobial activity was observed, with MIC and MLC values between 0·32 and 0·64 mg l-1 . However, the concentration of EO necessary for the eradication of planktonic cells was insufficient to significantly reduce the biofilm biomass of some isolates. Nevertheless, cell culturability and overall cellular metabolism was strongly reduced in all biofilms tested, only when the EO was tested. Contrary to the tested antibiotics, T. capitata EO showed a significant antimicrobial activity against MRSA biofilms, by reducing cellular metabolism and cellular culturability.

How different is the proteome of the extended spectrum ß-lactamase producing Escherichia coli strains from seagulls of the Berlengas natural reserve of Portugal?

UNLABELLED: ß-Lactam antibiotics like cefotaxime are the most commonly used antibacterial agents. Escherichia coli strains 5A, 10A, 12A and 23B isolated from Seagulls feces, are cefotaxime-resistant strains that produces extended-spectrum beta-lactamases. Bacterial resistance to these antibiotics occurs predominantly through structural modification on the penicillin-binding proteins and enzymatic inactivation by extended-spectrum ß-lactamases. Using classical proteomic techniques (2D-GE) coupled to mass spectrometry and bioinformatics extended analysis, in this study, we report several significant differences in cytoplasmic proteins expression when the strains were submitted to antibiotic stress and when the resistant strains were compared with a non-resistant strain. A total of 79 differentially expressed spots were collected for protein identification. Significant level of expression was found in antibiotic resistant proteins like ß-lactamase CTX-M-1 and TEM and also in proteins related with oxidative stress. This approach might help us understand which pathways form barriers for antibiotics, another possible new pathways involved in antibiotic resistance to devise appropriate strategies for their control already recognized by the World Health Organization and the European Commission. BIOLOGICAL SIGNIFICANCE: This study highlights the protein differences when a resistant strain is under antibiotic pressure and how different can be a sensible and resistant strain at the protein level. This survey might help us to understand the specifics barriers for antibiotics and which pathways are involved in its resistance crosswise the wildlife.

Comparative proteomics of an extended spectrum ß-lactamase producing Escherichia coli strain from the Iberian wolf.

The Iberian wolf (Canis lupus signatus) is an endangered species native to the Iberian Peninsula. Due to their predatory and wild nature, these wolves serve as important indicators of environmental contamination by antimicrobial-resistant bacteria. ß-Lactam antibiotics like cefotaxime are the most commonly used antibacterial agents. Bacterial resistance to these antibiotics occurs predominantly through enzymatic inactivation by extended-spectrum beta-lactamases. Escherichia coli strain WA57, isolated from Iberian wolf feces, is a cefotaxime-resistant strain that produces extended-spectrum beta-lactamases. In this study, using 2D-GE combined with MS and bioinformatics, we report significant differences in the abundance of 40 protein spots (p<0.01) from the extracellular, periplasmic, cytoplasmic, and membrane sub-proteomes and the whole-cell proteome of WA57 exposed and non-exposed to cefotaxime. A total of 315 protein spots were collected for protein identification. The comparative proteomics presented gives an overview of the complex changes in expression and metabolism that occur when WA57 is stressed with cefotaxime. Abundance of chaperone, porin and export proteins is particularly affected showing that the stress response and transport functions might directly influence the antibiotic resistance of this strain. BIOLOGICAL SIGNIFICANCE: This study highlights the importance of proteomics in detecting protein expression changes in bacterial strains exposed to stress such as that caused by cefotaxime. This approach might help us understand which pathways form barriers for antibiotics. This article is part of a Special Issue entitled: Environmental and structural proteomics.

Antimicrobial resistance in faecal enterococci and Escherichia coli isolates recovered from Iberian wolf.

The aim of this study was to report the antimicrobial resistance, the molecular mechanisms associated and the detection of virulence determinants within faecal Enterococcus spp. and Escherichia coli isolates of Iberian wolf. Enterococci (n = 227) and E. coli (n = 195) isolates were obtained from faecal samples of Iberian wolf (Canis lupus signatus). High rates of resistance were detected for tetracycline and erythromycin among the enterococci isolates, and most of resistant isolates harboured the tet(M) and/or tet(L) and erm(B) genes, respectively. The blaTEM, tet(A) and/or tet(B), and aadA or strA-strB genes were detected among most ampicillin-, tetracycline- or streptomycin-resistant E. coli isolates, respectively. E. coli isolates were ascribed to phylogroups A (n = 56), B1 (91), B2 (13) and D (35). The occurrence of resistant enterococci and E. coli isolates in the faecal flora of Iberian wolf, including the presence of resistant genes in integrons, and virulence determinants was showed in this study. Iberian wolf might act as reservoir of certain resistance genes that could be spread throughout the environment.

Proteome of a methicillin-resistant Staphylococcus aureus clinical strain of sequence type ST398.

Proteomics is a powerful tool to analyze the differences in gene expression of bacterial strains. Staphylococcus aureus has long been recognized as an important pathogen in human disease. In order to investigate this pathogen, the proteome of a clinical methicillin-resistant S. aureus (MRSA) strain of the sequence type ST398 was determined using 2-DE. Using 2-DE we obtained a total of 105 spots the MRSA strain. Furthermore in correlation with bioinformatic databases, they allowed accurate identification and characterization of proteins, resulting in 227 identified proteins. There were found proteins related to basic function of the cell, but also proteins related to virulence like catalase, specific of S. aureus species, and proteins related to antibiotic resistance. Proteins associated with antibiotic resistance or virulence factors are related to genomic databases. The most abundant classes identified involved glycolysis, energy production, one-carbon metabolism, and oxidation-reduction process, all of which reflect an active metabolism. These results highlight the importance of proteomics to deepen in the knowledge of protein expression of MRSA strain of the lineage ST398, microorganism with diverse and important resistance mechanisms. With this proteome map we have an essential tool for a better understanding of this pathogen and providing new data for protein databases. This article is part of a Special Issue entitled: Proteomics: The clinical link.

Detection of extended-spectrum beta-lactamase-producing Escherichia coli isolates in faecal samples of Iberian lynx.

AIMS: To characterize the diversity of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates recovered within the faecal microbiota of Iberian lynx. The identification of other associated resistance genes and the analysis of clonal relationship were also focused in this study. METHODS AND RESULTS: From 2008 to 2010, 128 faecal samples of Iberian lynx (wild and captive animals) were collected. Eleven tested samples contained cefotaxime-resistant E. coli isolates (all belonging to captive animals) and 10 ESBL-producing isolates were showed. CTX-M-14 and SHV-12 ESBL-types were detected and seven different patterns were identified by pulsed-field gel electrophoresis analysis. CONCLUSIONS: The occurrence of unrelated multiresistant E. coli in faecal flora of captive specimens of Iberian lynx, including the presence of ESBLs, resistant genes in integrons and virulence determinants was showed in this study. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained in this study highlight the environmental problem as future reintroductions of Iberian lynx could lead to a spread of resistant bacteria. Additionally, ESBL-producing bacteria can represent a health problem for this endangered species.

Genetic characterisation of extended-spectrum ß-lactamases in Escherichia coli isolated from retail chicken products including CTX-M-9 containing isolates: a food safety risk factor.

1. Bacterial resistance to ß-lactam antibiotics has risen dramatically in Escherichia coli from food animals. In a previous study, 29 randomly selected chicken products, collected in Portugal, were analysed for the presence of extended-spectrum ß-lactamases (ESBLs)-producing E. 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. ß-lactamases genes were identified as follows: bla (CTX-M-14) (n = 4), bla (CTX-M-1) (n = 2), bla (CTX-M-9) (n = 4) and bla (TEM-52) (n = 13). Mutations at positions -42, -18, -1, and +58 of ampC promoter region were identified in 4 non-ESBL-producing isolates. The tet(A) or tet(B) genes were identified in all tetracycline-resistant isolates; the aadA gene detected in 8 of 10 streptomycin-resistant isolates; the aac(3)-II gene in all gentamicin-resistant isolates; the cmlA gene in the chloramphenicol-resistant isolate; and sul1 and/or sul2 and/or sul3 genes were found in all trimethoprim-sulfamethoxazole-resistant isolates. The intI1 gene was detected in 8 trimethoprim-sulfamethoxazole-resistant isolates and the intI2 gene 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, or papC) was detected in 74·1% of the cefotaxime-resistant isolates. 4. Because ESBLs-producing bacteria are resistant to a broad range of ß-lactams, infections caused by these organisms complicate therapy and limit treatment options.

Antimicrobial activity and occurrence of bacteriocin structural genes in Enterococcus spp. of human and animal origin isolated in Portugal.

The main objective of this study was to detect the antimicrobial activity and the presence of bacteriocin structural genes in 224 enterococcal isolates from fecal origin obtained from humans, pets, wild animals and birds. Direct antimicrobial activity against Listeria monocytogenes CECT4032 was detected in 102 (45.6%) of the tested isolates. From these, only 22 displayed bacteriocin activity against this indicator. The bacteriocinogenic strains contained one or more of the bacteriocin structural genes tested in this study, with those of enterocins P, A and L50 (L50A and L50B) being the most abundant. Our results show a high occurrence of the combination of different bacteriocin structural genes in the enterococcal isolates analyzed, indicating an elevated genetic potential of these strains to produce various bacteriocins.

Genomic and proteomic evaluation of antibiotic resistance in Salmonella strains.

Using Salmonella strains identical to those present in the gastrointestinal tract of different animals we aim to determine and compare the proteome of two serotypes, Salmonella Typhimurium and Enteritidis recovered from faecal samples of wild boars and wild rabbits, respectively. The presence of genes responsible for antibiotic resistance was detected by PCR. Proteomes of the two distinct serotypes were determined using 2-DE in order to identify proteins associated with antibiotic resistance or virulence. Through 2-DE we obtained a total of 229 spots from both strains. All were suitable for MALDI-TOF/TOF and, in correlation with bioinformatic databases, allowed accurate identification and characterization of proteins. S. Enteritidis recovered from wild rabbits was sensitive to all the antibiotics tested in contrast to S. Typhimurium isolated from wild boars which presented a resistance phenotype to ampicillin, streptomycin and chloramphenicol. Nevertheless, despite the different ratio of proteins observed in each proteome according to their biological function, no significant difference was observed in the involvement of these proteins in pathogenicity. Bearing in mind that serotypes are related 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.

MLST and a genetic study of antibiotic resistance and virulence factors in vanA-containing Enterococcus from buzzards (Buteo buteo).

AIMS: To analyse the occurrence of faecal carriage of vancomycin-resistant enterococci (VRE) in Buteo buteo and to study the associated resistance and virulence genes. METHODS AND RESULTS: The presence of VRE was investigated in 33 faecal samples of B. buteo. Samples were seeded in Slanetz-Bartley agar plates supplemented with vancomycin for VRE recovery. Genes encoding antimicrobial resistance and virulence were studied by polymerase chain reaction. Vancomycin-resistant Enterococcus faecium isolates were characterized by multilocus sequence typing. VRE with an acquired mechanism of resistance (vanA genotype) were detected in 9% of samples analysed (Ent. faecium and Enterococcus durans). In addition, 27% of samples contained VRE with an intrinsic mechanism of resistance (Enterococcus gallinarum, vanC1). All vanA-containing isolates showed resistance to tetracycline and erythromycin and harboured the tet(M) and/or tet(L) genes, in addition to the ermB gene. The vat(E) and/or vat(D), cat(A) and aph(3')-IIIa genes were identified in quinupristin-dalfopristin-, chloramphenicol-, and kanamycin-resistant vanA-containing strains, respectively. The sequence types ST273 and ST5 were identified in two vanA-positive Ent. faecium isolates, and the presence of hyl, gelE, cylA, cylL and cylM virulence genes and gelatinase activity were identified in Ent. faecium ST5 strain. CONCLUSIONS: The intestinal tract of B. buteo could be a reservoir of vanA-positive enterococci. SIGNIFICANCE AND IMPACT OF THE STUDY: First study focused to define the occurrence of vanA-containing Enterococcus strains in B. buteo.

Detection and genetic characterisation of vanA-containing Enterococcus strains in healthy Lusitano horses.

Lusitano horses were investigated in order to detect the presence of vancomycin-resistant enterococci. vanA isolates showed high level vancomycin (Minimum inhibitory concentration; MIC > or = 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.

Genetic characterization of antibiotic resistance in enteropathogenic Escherichia coli carrying extended-spectrum beta-lactamases recovered from diarrhoeic rabbits.

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 beta-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 bla(TEM) 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.

Antimicrobial resistance and phylogenetic groups in isolates of Escherichia coli from seagulls at the Berlengas nature reserve.

Fifty-three faecal samples from yellow-legged gulls (Larus cachinnans) at the Berlengas nature reserve in Portugal were cultured on Levine agar plates not supplemented with antimicrobial agents, and one Escherichia coli colony was isolated and identified from each sample. The percentages of resistant isolates for each of the drugs were ampicillin (43.4 per cent), tetracycline (39.6 per cent), nalidixic acid (34.0 per cent), streptomycin (32.1 per cent), trimethoprim-sulfamethoxazole (SXT) (26.4 per cent), ciprofloxacin (18.9 per cent), chloramphenicol (18.9 per cent), gentamicin (7.5 per cent), tobramycin (7.5 per cent) amikacin (5.7 per cent) and amoxicillin-clavulanic acid (1.9 per cent). All the isolates were susceptible to cefoxitin, ceftazidime, cefotaxime, aztreonam and imipenem. The following resistance genes were detected: bla(TEM) (17 of 23 ampicillin-resistant isolates), tet(A) and/or tet(B) (18 of 21 tetracycline-resistant isolates), aadA (12 of 17 streptomycin-resistant isolates), cmlA (all chloramphenicol-resistant isolates), aac(3)-II with or without aac(3)-IV (all four gentamicin-resistant isolates), and sul1 and/or sul2 and/or sul3 (all 14 SXT-resistant isolates). The intI1 gene was detected in 10 of 14 SXT-resistant isolates, and three of them also contained class 2 integrons; four different gene cassette arrangements were identified among class 1 integrons (aadA, dfrA1+aadA1, dfrA12+orfF+aadA2 and sat+psp+aadA2) and one among the class 2 integrons (dfrA1+sat+aadA1). Ninety per cent of the isolates were included in the A or B1 phylogenetic groups.

Situação epidemiológica da leucose bovina enzoótica em Portugal entre os anos de 1995 e 2005 / Epidemiological survey of enzootic bovine leukosis in Portugal from 1995 to 2005

This paper evaluated the epidemiological situation of the enzootic bovine leucosis from 1995 to 2005, in Portugal. With exception of the South region, Algarve, the disease was distributed throughout the country, being more prevalent in the north, between Douro and Minho and Trás-os-Montes, than in the centre. A decrease in prevalence and incidence of the infection throughout the studied period was also observed.

Detecção da resistência a antibióticos de bactérias isoladas de casos clínicos ocorridos em animais de companhia / Detection of antibiotic resistance in clinical bacterial strains from pets

The identification of different bacterial strains and the occurrence of antibiotic resistance were investigated in several infection processes of pets as skin abscess with purulent discharge, bronco alveolar fluid, earwax, urine, mammary, and eye fluid. Streptococcus spp. and Staphylococcus spp. were the most detected in the different samples. A high frequency of antimicrobial resistance has been observed and this could reflect the wide use of antimicrobials in pets, making the effectiveness of antibiotic treatment to become more complicated.

Phenotypic and genotypic study of gelatinase and beta-haemolysis activities in faecal enterococci of poultry in Portugal.

The detection of gelatinase and beta-haemolysis activities was carried out in 83 faecal enterococci (43 Enterococcus faecalis, 33 E. faecium, five E. durans and two E. hirae) of poultry origin. In addition, the presence of genes of the gelE-fsrABC locus and of the cyl operon (cylL(L), cylL(S), cylA, cylB and cylM) were studied by polymerase chain reaction and correlated with gelatinase and beta-haemolysis production, respectively. Most of our E. faecalis isolates were gelatinase-positive (88%), being this activity not frequent in the other enterococcal species (2.5%). Only one of the 33 E. faecium isolates showed a positive gelatinase reaction. All enterococci that showed gelatinase activity harboured the gelE and fsrABC genes, although these genes were also detected in four E. faecalis and one E. durans gelatinase-negative isolates. Most of our non-E. faecalis gelatinase-negative isolates did not harbour gelE-fsrABC genes. A high proportion of faecal enterococci of poultry origin harboured genes of the cyl operon (71%), although only 7% contained the five cyl tested genes (all of them E. faecalis). Only one isolate of our series could express beta-haemolysis, harbouring the whole cyl operon. The cylL(S) genotype was the most prevalent in our enterococci (39%) and also the most prevalent among our E. faecalis isolates (60%). Other genotypes detected were the following ones (% of enterococci): cylA + cylB + cylM (13%), cylL(L) + cylA (4%), cylL(L) (4%), cylL(L) + cylA + cylB + cylM (2%), cylL(L) + cylA + cylM (1%) and cylA + cylM (1%). Both phenotypic and genotypic assays are important to evaluate the virulence potential of enterococci.

Antibiotic resistance and mechanisms implicated in clinical enterococci in a Tunisian hospital.

Susceptibility testing for 15 antibiotics was performed in a series of 191 clinical enterococci recovered in a Tunisian Hospital during 2000-2003. Species detected were the following ones (number of isolates): E. faecalis (139), E. faecium (41), E. casseliflavus (5), E. gallinarum (3), E. avium (2) and E. hirae (1). The percentages of antibiotic resistance detected were as follows (E. faecalis/ E. faecium/ other species) : penicillin (0/ 73/ 9%), tetracycline (78/ 44/ 54%), chloramphenicol (52/ 29/ 27%), erythromycin (66/ 100/ 82%), spiramycin (84/ 83/ 64%), pristinamycin (100/ 0/ 73%), trimethoprim-sulfamethoxazole (88/ 78/ 91%), rifampicin (72/ 41/ 0%), vancomycin (0/ 0/ 36%), teicoplanin (0/ 0/ 0%), high-level-resistance for gentamicin (24/ 29/ 45%), streptomycin (34/ 56/ 55%) and kanamycin (41/ 68/ 55%). Increased vancomycin minimum inhibitory concentrations (MICs) were only detected in E. casseliflavus and E. gallinarum isolates (MIC range 8-24 microg/ml). The erm(B), catA, tet(M), aac(6')-aph(2''), aph(3')-IIIa, and ant(6)-Ia genes were detected in 91%, 32%, 86%, 98%, 100%, and 72% of the E. faecium and E. faecalis isolates resistant to erythromycin, chloramphenicol, tetracycline and high-level-resistant to gentamicin, kanamycin and streptomycin, respectively. A total of 20 unrelated pulsed-field-gel-electrophoresis patterns were found in the series of 46 high-level gentamicin-resistant E. faecalis and E. faecium isolates of this study.

Characterization of antibiotic resistance genes and virulence factors in faecal enterococci of wild animals in Portugal.

Antibiotic susceptibility was tested in 140 non-selected enterococci (73 Enterococcus faecalis, 45 E. faecium and 22 of other species) recovered from faecal samples of 77 wild animals in Portugal. Susceptibility testing for 11 antibiotics (vancomycin, teicoplanin, ampicillin, streptomycin, gentamicin, kanamycin, chloramphenicol, tetracycline, erythromycin, quinupristin-dalfopristin and ciprofloxacin) was determined by disk diffusion and agar dilution methods. Forty-four isolates (31.4%) showed susceptibility to all the antibiotics tested (5.5% of E. faecalis; 62.2% of E. faecium; and 78.6% of E. hirae). Neither ampicillin-resistance nor acquired-vancomycin-resistance was detected and 1.4% of the isolates showed high-level-resistance for gentamicin or streptomycin. Tetracycline and erythromycin resistances were shown in 28.6% and 20.1% of the isolates, respectively. Antibiotic resistance genes were studied by polymerase chain reaction (PCR) and sequencing and tet(M) + tet(L), erm(B) or aac(6')-aph(2'') genes were detected in most of tetracycline-, erythromycin- or gentamicin-resistant enterococci respectively. Genes encoding virulence factors were studied by PCR and a wide variety of virulence genes were detected in most of E. faecalis isolates but were rarely found in E. faecium and not detected in the other species. The prevalence of genes encoding virulence factors in E. faecalis was as follows: cpd (98.6%), gelE (75.3%), agg (30.1%), fsr (17.8%), ace (9.6%) and esp (4.1%). Low percentages of antibiotic resistance was found in the faecal enterococci of wild animals but a wide variety of virulence genes were detected among E. faecalis isolates although were rare in the other species.

Enterococcus spp. resistentes à vancomicina isolados de fezes de frangos, pombos, gamos e ratos / Vancomycin-resistant Enterococcus isolated from feces of poultry, pigeons, deers and rats

The occurrence of vancomycin resistant enterococci (VRE) was investigated in feces of poultry, pigeons, deers and rats. Feces samples were collected from 25 broilers growing in poultry production farms that never used in the diets avaporcine as growth promoter, 6 broiler from different poultry production farms that used regularly avaporcine in the formulated diets until 1997, 8 deers from natural reservoirs, 15 pigeons, and 20 rats arrested from field conditions. The samples of Enterococcus gallinarum isolated from poultry feces were resistant to vancomycin independently of the use of avaporcine in the formulated diet.

Resposta imunitária à vacinaçäo conjuntival com a estirpe Rev.1 de Brucella melitensis em ovinos e caprinos / Serological response of sheep and goats to conjunctival Brucella melitensis Rev.1 vaccine

The live B. melitensis Rev.1 strain is considered the best vaccine available for the prophylaxis of brucellosis in small ruminants, especially when used at the standard dose by the conjunctival route. In the present study a 1´ 10(9) CFU dose for both sheep and goats conjunctivally vaccinated was tested to evaluate the duration of serological responses. Conjunctival vaccination with Rev. 1 performed in adult animals induced a rapid rise in serological titres as measured by Rose Bengal Plate Test (RBPT), Complement Fixation Test (CF) and Modified Rose Bengal Plate Test (MRBPT). Titres then decreased and became negative in most animals by four months after vaccination (except MRBPT). The goats responded better to the vaccination than the sheep as one month after vaccination 100 percent of the goats revealed positive results to RB and RBM and 93.4 percent to FC test. The RBM was the one that detected more positive animals along the study