Decay of the distance autocorrelation and Lyapunov exponents.

This work presents numerical evidence that for discrete dynamical systems with one positive Lyapunov exponent the decay of the distance autocorrelation is always related to the Lyapunov exponent. Distinct decay laws for the distance autocorrelation are observed for different systems, namely, exponential decays for the quadratic map, logarithmic for the Hénon map, and power-law for the conservative standard map. In all these cases the decay exponent is close to the positive Lyapunov exponent. For hyperchaotic conservative systems the power-law decay of the distance autocorrelation is not directly related to any Lyapunov exponent.

Detection of mycobacteria in the bloodstream of patients with acquired immunodeficiency syndrome in a university hospital in Brazil.

This study was done to determine the occurrence of mycobacteria in the bloodstreams of patients with fever and advanced AIDS in a Brazilian hospital. We also verified the capability of an automated method for recovering these bacteria. During a period of 19 months, 254 patients with AIDS were evaluated. Blood cultures were generally submitted in pairs and drawn separately. Blood cultures were processed by the BACTEC 460TB System (Becton Dickinson Microbiology Systems, Sparks, MD), using the Bactec 13A media (Becton Dickinson Microbiology Systems, Sparks, MD). Of the 530 vials submitted, 77 (14.5%) from 41 (16%) patients were positive. Mycobacterium avium complex was recovered from 45 (58.4%) of the 77 positive vials, corresponding to 22 (53.6%) patients with positive blood cultures. The average time to detect Mycobacterium avium complex was 15 days. Mycobacterium tuberculosis was recovered from 26 (33.8%) of the 77 positive vials, corresponding to 15 (36.6%) patients with positive blood cultures, with an average detection time of 24 days. Other species of mycobacteria were recovered from 6 (7.8%) of the 77 vials, corresponding to 4 (9.8%) patients. M.avium complex was fairly prevalent (8.7%) in severely ill patients with AIDS in our hospital. M. tuberculosis was also an important (6.0%) agent of systemic bacterial infections in these patients. The rapid diagnosis of mycobacteremia was possible with the implementation of this automated technology.

Use of macrorestriction analysis to demonstrate interhospital spread of multiresistant Acinetobacter baumannii in São Paulo, Brazil.

We evaluated the spread of Acinetobacter baumannii strains among three hospitals located in São Paulo, Brazil. A total of 46 isolates, which were typed by chromosomal DNA analysis with use of pulsed field gel electrophoresis (PFGE), were tested for susceptibility to the fluoroquinolones, carbapenems, aminoglycosides (amikacin), cephalosporins, polymyxin B, and ampicillin/sulbactam by means of the broth microdilution method, disk diffusion, and the E-test. Isolates with an identical PFGE pattern (pattern B) that were susceptible only to carbapenems, polymyxin B, and ampicillin/ sulbactam were recovered in all three hospitals. In addition, isolates with PFGE pattern A that were susceptible only to polymyxin B and ampicillin/sulbactam were recovered in hospitals 1 and 2. The results of our study strongly suggest the interhospital transmission of multiresistant epidemic strains of A. baumannii in São Paulo. Once in the hospital, these strains can disseminate and cause outbreaks with devastating consequences.

Infecçäo por Listeria monocytogenes pós-transplante renal: relato de seis casos / Infection by Listeria monocytogenes following renal transplantation: report of 6 cases

Säo relatados 6 casos de listeriose em pacientes transplantados renais, que ocorreram entre 13 dias e 57 meses após iniciarem imunossupressäo clássica, sendo 3 casos classificados como meningite, 2 casos como meningoencefalite e 1 caso como bacteremia. Houve um óbito e os 5 pacientes restantes apresentaram boa evoluçäo. Com dados adicionais da literatura, säo discutidos a epidemiologia, o diagnóstico e tratamento, da listeriose pós-transplante renal