Aims: To isolate and to characterize the diversity of Chromobacterium violaceum from the Brazilian Amazon region. Methods and Results: Twenty-two isolates were obtained from the waters and banks of the river Negro, in the Brazilian Amazon. All isolates were able to grow in vitro at 44°C and pH 4AE0, but were adversely affected by temperatures below 15°C, and unable to survive at 4°C, properties that may be related to the adaptation to the ecosystem. The isolates were joined at a final level of similarity of only 13% in the rep-PCR analysis. The analysis of 16S rRNA genes resulted in three main groups clustered at a final level of similarity of 97% and only three isolates were clustered with the type strain. Similar data were obtained for the 23S rRNA gene. Conclusions: A high level of genetic diversity was verified with indications that the Brazilian isolates would fit into at least two new clusters besides C. violaceum species. Significance and Impact of the Study: The results show remarkable bacterial adaptability and genetic diversity of C. violaceum in the Amazon region.

Neste estudo, realizou-se genotipagem de isolados de Mycobacterium bovis, provenientes de amostras de tecidos de bovinos positivos no teste cervical comparativo (TCC) para tuberculose em Mato Grosso do Sul, por meio da técnica de spoligotyping. Tecidos de 13 bovinos positivos, oriundos de diferentes municípios do estado, foram cultivados em meio de Stonebrink. As colônias resultantes foram submetidas à coloração de Ziehl-Neelsen e todos os isolados apresentaram características tintoriais de BAAR. Os 13 isolados de BAAR foram identificados por PCR multiplex (mPCR). O gene hsp65 foi alvo para identificação de Mycobacterium spp, a sequência de inserção IS6110 foi alvo para identificação de complexo Mycobacterium tuberculosis (CMT) e a região rvd1rv2031c foi explorada para detecção de M. bovis. Os isolados micobacterianos foram genotipados pela técnica de spoligotyping. Dos 13 bovinos, sete tinham pelo menos uma lesão sugestiva de tuberculose em linfonodos retrofaríngeos, parotídeos e pulmonares ou no pulmão, e em seis não foram encontradas lesões visíveis sugestivas da doença. Na mPCR, 11/13 (84,6%) isolados foram positivos para Mycobacterium spp; 8/13 (61,5%) positivos para CMT e 7/13 (53,8%) positivos para M. bovis. Com base no spoligotyping, oito isolados de BAAR foram agrupados dentro de três diferentes agrupamentos de genótipos e uma amostra remanescente apresentou perfil único, sendo quatro isolados com padrão de espoligotipo SB0121, dois SB1145, dois SB0881 e um SB0140. A técnica de spoligotyping demonstrou que há diversidade genética entre os espoligotipos presentes no estado de Mato Grosso do Sul, embora predomine o perfil SB0121

No abstract

Leptospirosis is a disease of worldwide distribution that affects man and several animal species. Domestic and wild animals can behave as reservoirs of the agent. The aim of this study was to evaluate the frequency of anti-Leptospira spp. antibodies in dogs and wild small mammals from rural properties and conservation units of three municipalities of Rio Grande do Sul State, Brazil. Sera were collected from 192 domestic dogs and 132 small mammals, namely rodents of the Cricetidae and Caviidae families and marsupials of the Didelphidae family. The study used Microscopic Agglutination Test (MAT) against 23 serovars of Leptospira spp. Overall, 9.90% (19/192) dogs, and 1.51% (2/132) small mammals were seropositive. Leptospira interrogans serovar Australis was the most frequent serovar in dogs and antibodies against L. interrogans serovar Pomona were detected in a dog and a small mammal belonging to the same municipality. We conclude that in the regions studied the frequency of seropositivity in dogs is low, and leptospires do not seem to be circulating in small mammals, yet, further research is necessary to assess the real role that these animals may have for leptospirosis in the studied areas. This is the first serological survey in small mammals, including wild rodents, in the area that encompasses conservation units of great importance to Rio Grande do Sul state.

This study aimed to evaluate virulence factors and genetic markers of antimicrobial resistance in 400 Staphylococcus aureus strains isolated from bovine mastitis in four Brazilian states, as well as to assess the association between these characteristics and field information. Virulence factors and drug resistance genes were identified by PCR screening. Biofilm-forming and hemolytic phenotype were detected using Congo red Tryptic Soy Broth and defibrinated sheep blood agar, respectively. Of all isolates, 83.5% were biofilm-forming and 98.5% strains exhibited biofilm gene icaAD, and a significant association between phenotype and genotype for biofilm was observed (P = 0.0005). Hemolysin genes were observed in 82.85% (hla + hlb +), 16.5% (hla +) and 0.75% (hlb +) isolates, whereas the hemolytic phenotype exhibited was complete and incomplete hemolysis in 64.25%, complete in 28.25%, incomplete in 4.75%, and negative in 2.75% of the strains. Virulence factors genes luk, seb, sec, sed, and tst were observed in 3.5%, 0.5%, 1%, 0.25%, and 0.74% isolates, respectively. The gene blaZ was detected in 82.03% of penicillin-resistant isolates, whereas tetK and aac(6′)-Ie-aph(2′)-Ia were observed in 33.87% and 45.15% of the tetracycline and aminoglycosides-resistant isolates, respectively. Fluoroquinolone resistance gene mepA was detected for the first time in S. aureus from bovine mastitis. Resistance genes tetM (3.22%), tetL (1.61%), ermA (14.29%), ermB (14.29%), ermC (33.3%), ermT (9.52%), ermY (4.76%), msrA (9.52%), and mphC (9.52%) were also detected among resistant isolates. No association between virulence factors or antimicrobialresistant genes and year of isolation, geographic origin, or antimicrobial resistance profile was observed. Our results showed that S. aureus strains isolated from bovine mastitis in the four Brazilian states sampled are mainly biofilmforming and hemolytic, whereas virulence genes associated with enterotoxins, luk and tst, were less frequently observed. Moreover, a wide variety of resistance genes that confer resistance to almost all classes of antimicrobial agents approved for use in animals and humans were found. Overall, the data point to a great pathogenic potential of S. aureus associated with bovine mastitis and to the non-negligible risks to public health of staphylococcal infections from animal origin.