A comparison of virulence patterns and in vivo fitness between hospital- and community-acquired methicillin-resistant Staphylococcus aureus related to the USA400 clone.

Methicillin-resistant Staphylococcus aureus (MRSA) isolates genetically related to the CA-MRSA clone MW2/USA400 (ST1-SCCmecIV lineage) from the United States have emerged in hospitals in Rio de Janeiro and are associated with nosocomial bloodstream infections. To understand the virulence mechanisms involved in the adaptability of ST1 isolates as a hospital pathogen in Rio de Janeiro, we compared the virulence traits and fitness properties of the Brazilian isolates with those displayed by the CA-MRSA isolates from the United States. Similar to the USA400 from the United States, all the Brazilian isolates tested carried the genes encoding SEH and LukDE. In contrast, none of the Brazilian isolates carried the lukSF PVL, sea, sec, and sek genes. Competition experiments in mice demonstrated a significant increase in the fitness for the CA-MRSA isolates MW2 and USA400-0051 from the United States compared to other isolates. In the foreign body animal model, 83 % more North-American bacterial cells were recovered compared to the Brazilian ST1 isolates. Differences in gene expression of important virulence factors were detected. Transcription of rnaIII and psmα3 was increased about two-fold in the isolates from the United States, and sasG about two-fold in the Brazilian isolates. Thus, it is possible that the virulence attenuation observed among the Brazilian hospital isolates, associated with the acquisition of multiple resistant determinants, are consequences of microevolutionary events that contributed to the necessary fitness adjustment of this lineage, allowing a typically community-acquired MRSA (MW2/USA400) to emerge as a successful hospital pathogen (Brazilian ST1-SCCmecIV).

Virulence characteristics of genetically related isolates of group B streptococci from bovines and humans.

The present study had the objective of evaluating the pathogenic potential of the genetically related strains of Streptococcus agalactiae no. 80427 (human origin) and no. 87159 (bovine origin), and comparing the results with two other strains isolated from bovine mastitis (no. 87244) and invasive human infection (no. 90356), with no genetic or epidemiologic relationship between them or with the first 2 isolates. Virulence genes hylB (hyaluronidase) and lmb (laminin-binding protein) were detected in the 4 strains, and genes bac (beta protein) and bca (alpha protein) were only detected in human strains. The protein profile obtained using SDS-PAGE did not indicate any differences between the 4 strains. No significant difference was detected between human and bovine strains in the assays of adherence to and invasion of 16HBe cells, as well as in the resistance assay for intracellular bacterial survival in macrophages. However, the strain 87159 exhibited a greater survival in the killing test with whole human blood and was more virulent in newborn mice than the 80427 strain. The strain 87244 was not virulent in mice. These data suggest that isolates of human and bovine origins may express similar virulence attributes, leading to a possible, however limited, dissemination.

Genetic relatedness between group B streptococci originating from bovine mastitis and a human group B Streptococcus type V cluster displaying an identical pulsed-field gel electrophoresis pattern.

Twenty isolates of group B streptococcus (GBS) were recovered from the milk of cows with bovine mastitis on three farms located in the south and south-east of Brazil between 1987 and 1988. These isolates were characterised by molecular methods and compared with a collection of 103 human GBS isolates from colonised and infected patients in the same region between 1980 and 2003. Some of the bovine isolates shared identical or similar pulsed-field gel electrophoresis (PFGE) patterns with a PFGE clone of human GBS type V. In addition, these bovine and human isolates also possessed the same ribotype. Multilocus sequence typing (MLST) of representative isolates confirmed the genetic relationship between the human and bovine GBS isolates with identical PFGE patterns, which clustered in the same ST-26 clonal complex. These data support the hypothesis that some bovine GBS strains are related closely to human isolates and may infect humans, or vice versa. Further comparative genomic analyses of GBS isolates from bovine and human origins are required to investigate this hypothesis further.

Pulsed-field gel electrophoresis of human group B streptococci isolated in Brazil.

The present study addresses epidemiological aspects of Brazilian human group B streptococci (GBS). GBS (103 isolates) were serotyped with specific rabbit anticapsular antibodies by double diffusion in agarose gels. They represented 3 serotypes: 26 II, 41 III, and 36 V. Thereafter, the strains were characterized by pulsed-field gel electrophoresis (PFGE) of DNA treated with SmaI. DNA restriction band sizes were compared and displayed 54 PFGE profiles that were arranged into 18 patterns. Of the predominant patterns detected for the 41 type III isolates 4 were observed in 15 strains from individuals with infections whereas only 3 were identified in 22 streptococci from healthy carriers. Such differences did not separate types II and V streptococci from carriers and patients. The PFGE method is a sensitive, precise, and powerful tool for discriminating streptococcal strains for epidemiological purposes.

1H and 13C NMR spectra of 3,8-dimethoxyfuro[3,2-g]coumarin and maculine from Esenbeckia grandiflora Martius (Rutaceae).

One- and two-dimensional NMR experiments were used for the unambiguous assignment of the (1)H and (13)C NMR chemical shifts of the furoquinoline alkaloid maculine (1) and the new furanocoumarin 3,8-dimethoxyfuro[3,2-g]coumarin (2).

Total assignment of 1H and 13C NMR spectra of the alkaloid 3,3-diisopentenyl-N-methyl-2,4-quinoldione and novel reaction derivatives.

One- and two-dimensional NMR experiments were used for the unambiguous assignment of the 1H and 13C NMR chemical shifts of 3,3-diisopentenyl-N-methyl-2,4-quinoldione and five novel reaction derivatives.

Study of pulmonary experimental paracoccidioidomycosis by analysis of bronchoalveolar lavage cells: resistant vs. susceptible mice.

Adult Swiss (susceptible) and BALB/c (non-susceptible) mice were inoculated by the intravenous route with 1 x 10(6) yeast cells of Paracoccidioides brasiliensis, strain 18. Immunologic parameters, histopathology and features of the bronchoalveolar lavage (BAL) were evaluated at week 2, 4, 8 and 16 post-infection. The pulmonary infection was progressive in Swiss mice and regressive in Balb/c mice. The numbers of total cells, lymphocytes and polymorphonuclear neutrophils increased in BAL, as well as the percentages of giant cells, and CD4 and CD8 positive cells. The ultrastructural study of BAL cells revealed a predominance of macrophages and a frequency of 13.2% of type II pneumocytes. As the infection progressed, the number of fungal cells and spreading macrophages, as well as the stimulated release of H2O2 by macrophages, increased. The animals exhibited an exacerbation of the humoral immune response and a depression of cellular immunity during the infection. There was a good correlation between the intensity and the pattern of the pulmonary histopathology and the cellular findings in the BAL. The present model reproduces some anatomoclinical patterns of the human disease and shows that BAL may be a useful tool in monitoring the pulmonary infection caused by P. brasiliensis.

Sputum cytology in the diagnosis of pulmonary paracoccidioidomycosis.

The presence of Paracoccidioides brasiliensis was determined in sputum samples from 50 patients with paracoccidioidomycosis using four different techniques: (a) cell-block preparations stained with silver methenamine, (b) direct microbiologic examination, (c) smears stained with Shorr, and (d) smears stained with silver methenamine. Overall, cell-block preparations and smears stained with silver methenamine proved to be the most sensitive techniques, followed by smears stained with Shorr and direct microbiologic examination in decreasing order of sensitivity. Sputum cytology tended to be less positive in patients with interstitial pulmonary lesions as determined by chest X-ray than in patients with alveolar lesions. In addition to its high sensitivity, cell-block preparation technique allows storage of blocks and slides for further studies.

Cytochemical evaluation of gamma-glutamyl-transpeptidase activity in cervical smears.

The cervicovaginal smears of 43 patients attending an outpatient service for early cancer detection were cytochemically studied for the presence of gamma-glutamyl-transpeptidase (GGT) in epithelial cells. This was done in order to evaluate such an enzyme phenotype as a marker for cancer development. The results showed that 70% of the 38 patients with a cytologic diagnosis of "inflammatory" or preneoplastic/neoplastic conditions had GGT-positive cells in their smears. None of the five cytologically normal cases showed any epithelial cells with GGT activity. Although most of the GGT-positive cells were metaplastic, some morphologically normal, dysplastic or neoplastic cells also expressed the enzyme. The data suggest that cytochemically detectable transpeptidase activity appears whenever alterations of the normal epithelial microenvironment occurs, but is not necessarily linked to the carcinogenic process. Therefore, cytochemically GGT-positive cells should not be used as an indicator of neoplastic transformation of the cervical epithelium.

[Walker's 256 carcinosarcoma: metastatic dissemination in two cell lines (author's transl)]. / Carcino-sarcoma 256 de Walker: disseminação metastática em duas linhagens do tumor.

Walker's 256 carcinosarcoma a transplantable tumor of the rate changes its behaviour as a consequence of various factors. In this paper we compare the evolution of 2 lines of the tumor: WM 16 (muscular) and Christ Hospital (ascitic) both inoculated intramuscularly. Animals receiving line WM 16 had a severe rapidly progressive evolution dying around day 14 after inoculation with diffuse metastases to lymph nodes (65% of animals), kidneys (53%), spleen (50%), lungs (46.5%), liver (45%), bone marrow (44.8%), in 56% of the animals there were circulating tumoral cells. Animals receiving Christ Hospital line survived up to 40 days, metastases were limited do lungs (48.7%) and lymph nodes (31.7%) and only in 2 of 45 animals circulating tumoral cells were observed.