Abstract. During 1985During -1995 clinically and epidemiologically compatible with Brazilian spotted fever were identified in 17 patients in the county of Pedreira, in the state of São Paulo, Brazil. Spotted-fever group rickettsial infection was confirmed by serology and/or immunostaining of tissues in 10 of these patients. Immunostaining confirmed infection in a 37-year-old pregnant patient, although rickettsial antigens were not demonstrable in the tissues of the fetus. A serosurvey was conducted in four localities in the county to determine the prevalence of subclinical or asymptomatic infections with spotted fever group rickettsiae. Five hundred and twenty-five blood samples were tested by an indirect immunofluorescence assay for antibodies reactive with Rickettsia rickettsii. Twenty-two (4.2%) of these samples demonstrated titers Ն 1:64. The results indicate that Brazilian spotted fever is endemic within this region of Brazil.

Staphylococcus aureus is an important nosocomial and community-acquired pathogen. Hospital infections are frequently complicated by the ability of bacteria to form biofilms on different surfaces. The development of bacterial films on medical indwelling devices, such as prostheses, often requires surgical procedures to remove the contaminated implant. Indeed, biofilm formation on central endovenous catheters is a major cause of primary bacteraemia in hospitals. The modulation of virulence factors in S. aureus is orchestrated by a number of global regulators including agr RNAIII. To improve our understanding of the role of the agr quorum-sensing system in biofilm formation by S. aureus, we constructed a number of agr-null mutants, derived from contemporary clinical isolates. Analysis of these mutants indicates that agr has a significant impact on biofilm development for most of the isolates tested. Our data show that RNAIII can control both biofilm formation and accumulation. The agr effect included both up-and downregulation of biofilms, even for isolates within the same lineage, corroborating the hypothesis that the mechanisms involved in S. aureus biofilms are complex and probably multifactorial.

In order to obtain information on Brazilian spotted fever, a study in domestic animals was performed in the County of Pedreira, State of São Paulo, Brazil, where 17 human cases had been notified. Serum samples obtained from animals were tested by indirect immunofluorescence for detectable antibodies to spotted fever-group rickettsiae. Seropositivity was revealed in 12 (36.4%) of 33 dogs and seven (77.8%) of nine horses from the endemic area. For comparison, blood samples from dogs and horses from non endemic area were tested and four (12.9%) of 31 dogs and three (27.3%) of 11 horses were positive. The highest titers of antibodies by IFA (IgG > or = 1:1024) were found only in three dogs and six horses from endemic area. The results suggest that dogs as horses may serve as environmental sentinels for establishing the prevalence of foci of spotted fever in Brazil.

The prevalence of mutations that confer resistance to antiretroviral drugs was examined in 56 drug-naive, human immunodeficiency virus type 1 (HIV-1)-infected individuals from the Army Health Service in Rio de Janeiro, Brazil. No primary protease inhibitor mutations were found, but secondary mutations were observed in 51.2% of the samples. Fourteen percent of the viruses had reverse transcriptase inhibitor-associated mutations. Comparative analysis of protease secondary mutations from four different time periods in drugnaive patients in the city of Rio de Janeiro has indicated constant rates for particular mutations. Changes in CD4 cell counts and HIV viral load over time in subtype B-and non-B-infected drug-naive patients were not significantly different.

Ticks were collected from vegetation and animals at monthly intervals during one year (1993)(1994) 30(3):181-185, mai-jun, 1997. Revista da Sociedade Brasileira de Medicina Tropical ARTIGOSLemos ERS, Machado RD, Coura JR, Guimarães MAA, Freire NMS, Amorim M, Gazeta GS. Epidemiological aspects of the Brazilian spotted fever: seasonal activity of ticks collected in an endemic area in São Paulo, Brazil. Revista da Sociedade Brasileira de Medicina Tropical 30:181-185, mai-jun, 1997.

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