Distinct chitinases are expressed during various growth phases of the human pathogen Paracoccidioides brasiliensis

The aim of this work was the partial purification and subsequent evaluation of chitinase expression during the various growth phases of Paracoccidioides brasiliensis. Initially, PbCTS1r was expressed as a recombinant protein and displayed enzymatic activity against 4-MU-[N-acetylglucosamine (GlcNAc)]3 and 4-MU-(GlcNAc)2. Two proteins, 45 kDa and 39 kDa in size, were partially purified from P. brasiliensis yeast crude extract using cation-exchange chromatography coupled with HPLC and were characterised as PbCTS1 and PbCTS2, respectively. Anti-PbCTS1r antibody recognised two proteins in the crude extracts of yeast and the transitional stage between mycelial and yeast phases. In crude extracts of mycelium, only the 45 kDa protein was detected. However, quantitative real-time polymerase chain reaction led to the detection of small quantities of Pbcts2 transcript in the mycelial phase. In the yeast cell wall extract, only the 39 kDa protein was detected. Moreover, both proteins were secreted by the yeast parasitic phase, suggesting that these proteins participate in the modulation of the fungal environment. Phylogenetic analysis of the predicted PbCTS1 and PbCTS2 proteins indicated that they code for distinct chitinases in P. brasiliensis. During evolution, P. brasiliensis could have acquired the paralogues Pbcts1 and Pbcts2 for growth and survival in diverse environments in both saprophytic and parasitic phases.

Virulence factors and antimicrobial resistance of Escherichia coli isolated from urinary tract of swine in southern of Brazil / Fatores de virulência e resistência aos antimicrobianos de Escherichia coli isoladas do trato urinário de suínos do Sul do Brasil

The present study determined the molecular and resistance patterns of E. coli isolates from urinary tract of swine in Southern of Brazil. Molecular characterization of urinary vesicle samples was performed by PCR detection of virulence factors from ETEC, STEC and UPEC. From a total of 82 E. coli isolates, 34 (38.63 percent) harbored one or more virulence factors. The frequency of virulence factors genes detected by PCR were: pap (10.97 percent), hlyA (10.97 percent), iha (9.75 percent), lt (8.53 percent), sta (7.31 percent) sfa (6.09 percent), f4 (4.87 percent), f5 (4.87 percent), stb (4.87 percent), f6 (1.21 percent) and f41 (1.21 percent). Isolates were resistant to penicillin (95.12 percent), lincomycin (93.9 percent), erythromycin (92.68 percent), tetracycline (90.24 percent), amoxicillin (82.92 percent), ampicillin (74.39 percent), josamycin (79.26 percent), norfloxacin (58.53 percent), enrofloxacin (57.31 percent), gentamicin (39.02 percent), neomycin (37.8 percent), apramycin (30.48 percent), colistine (30.48 percent) and cefalexin (6.09 percent). A number of 32 (39.02 percent) E. coli isolates harbored plasmids.

O presente estudo teve por objetivo determinar os padrões moleculares e de resistência aos antimicrobianos de isolados de E. coli provenientes do trato urinário de suínos no Sul do Brasil. Os fatores estudados dividiram os patotipos ETEC, STEC e UPEC. Trinta e quatro (38,63 por cento) isolados avaliados apresentavam um ou mais dos fatores de virulência pesquisados. A freqüência dos genes de virulência detectados foram: pap (10,97 por cento), hlyA (10,97 por cento), iha (9,75 por cento), lt (8,53 por cento), sta (7,31 por cento) sfa (6,09 por cento), f4 (4,87 por cento), f5 (4,87 por cento), stb (4,87 por cento), f6 (1,21 por cento) e f41 (1,21 por cento). Os isolados foram resistentes à penicilina (95,12 por cento), lincomicina (93,9 por cento), eritromicina (92,68 por cento), tetraciclina (90,24 por cento), amoxacilina (82,92 por cento), ampicilina (74,39 por cento), josamicina (79,26 por cento), norfloxacina (58,53 por cento), enrofloxacina (57,31 por cento), gentamicina (39,02 por cento), neomicina (37,8 por cento), apramicina (30,48 por cento), colistina (30,48 por cento) e cefalexina (6,09 por cento). Trinta e dois (39,02 por cento) isolados de E. coli continham plasmídeos.

In vitro susceptibility to antifungal agents of clinical and environmental Cryptococcus neoformans isolated in Southern of Brazil

The purpose of the present study was to compare the susceptibility to four antifungal agents of 69 Cryptococcus neoformans strains isolated from AIDS patients with that of 13 C. neoformans strains isolated from the environment. Based on the NCCLS M27-A methodology the Minimal Inhibitory Concentrations (MICs) obtained for amphotericin B, itraconazole and ketoconazole were very similar for clinical and environmental isolates. Clinical isolates were less susceptible to fluconazole than environmental isolates. The significance of these findings and aspects concerning the importance, role and difficulties of C. neoformans susceptibility testing are also discussed