In vitro activity of antimicrobial combinations against multidrug-resistant Pseudomonas aeruginosa

Introduction Pseudomonas aeruginosa isolates related to nosocomial infections are often resistant to multiple antibacterial agents. In this study, antimicrobial combinations were evaluated to detect in vitro synergy against clinical isolates of P. aeruginosa. Methods Four clinical P. aeruginosa isolates were selected at random among other isolates from inpatients treated at the public University hospital in Ribeirão Preto, SP, Brazil. Two isolates were susceptible to imipenem (IPM-S) and several other antimicrobials, while the other two isolates were imipenem and multidrug resistant (IPM-R). The checkerboard method was used to assess the interactions between antimicrobials. Results Combinations of imipenem or other anti-Pseudomonas drugs with complementary antibiotics, such as aminoglycosides, fosfomycin and rifampin, reached synergy rates of 20.8%, 50%, 62.5% and 50% for the two IPM-S and two IPM-R Pseudomonas isolates, respectively. Imipenem, piperacillin-tazobactam and ceftazidime yielded a greater synergy rate than cefepime or ciprofloxacin. Synergist combinations were more commonly observed when the complementary drug was tobramycin (65%) or fosfomycin (57%). Conclusions Some antibacterial combinations led to significant reductions of the minimum inhibitory concentrations of both drugs, suggesting that they could be clinically applied to control infections caused by multidrug-resistant P. aeruginosa. .

Efficacy of voriconazole in experimental rat paracoccidioidomycosis

INTRODUCTION: Amphotericin B, azole or sulfamide drugs are used for treatment of patients with paracoccidioidomycosis. Among the azole drugs, voriconazole was active in vitro against Paracoccidioides brasiliensis and showed efficacy in the treatment of patients infected with this fungus.In the present study the antifungal activity of voriconazole and of other drugs was compared in a rat model of paracoccidioidomycosis. METHODS: Wistar rats were inoculated intravenously with the BOAS strain of P. brasiliensis and antifungal drugs were administered to the animals by gavage at the following doses (mg/kg weight/day): voriconazole (5 to 20), ketoconazole (12 to 15), fluconazole (6), itraconazole (4), and sulfamethoxazole-trimethoprim (120 to 150). The antifungal activity of the drugs was assessed by determining the P. brasiliensis colony forming units in the lungs and spleen of the animals at the end of treatment and by a survival study. RESULTS: Voriconazole reduced the total tissue fungal burden of P. brasiliensis, particularly at doses of ≥10mg/kg weight/day but its antifungal activity was less intense than that of fluconazole, itraconazole and sulfamethoxazole-trimethoprim. The mean survival of animals treated with the last three drugs, 29.1±10.7, 26.1± 10.1 and 28.4±9.6 days, respectively, was higher than that achieved with voriconazole 10mg/kg weight/day (18.5±8.3 days) and that observed in untreated animals (15.7±3.6 days). CONCLUSIONS: At doses similar to those used for clinical treatment, voriconazole showed lower antifungal activity in experimental rat paracoccidioidomycosis than that obtained with itraconazole and sulfamethoxazole-trimethoprim.

Serological diagnosis of paracoccidioidomycosis in HIV-coinfected patients

Paracoccidioidomycosis should be differentiated from other opportunistic diseases in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients who live in Latin America. Laboratory investigation can begin with serological tests, which are rapid and efficient. In the present study, double immunodiffusion (DID), counterimmunoelectrophoresis (CIEP) and an enzyme linked immunosorbent assay (ELISA) tests were assessed for the detection of anti-Paracoccidioides brasiliensis antibodies in 40 patients coinfected with HIV. The results were compared to those obtained for 75 non-HIV-infected patients with endemic paracoccidioidomycosis. Anti-P. brasiliensis antibodies were detected in 65 percent (DID), 79 percent (CIEP) and 95 percent (ELISA) of the patients with HIV/AIDS, significantly lower rates than those detected in cases of endemic paracoccidioidomycosis, which were 89 percent, 99 percent and 100 percent, respectively. The reactive sera of HIV-infected patients also showed lower anti-P. brasiliensis antibody titres than those of non-HIV-infected patients. Despite the lower intensity of the specific humoral response, serological tests are useful for the diagnosis of opportunistic paracoccidioidomycosis in the HIV/AIDS population. We suggest optimization of the laboratory diagnosis by combining the ELISA test with CIEP or DID.

Inquérito soroepidemiológico para infecções por fungos causadores de micoses sistêmicas na Reserva Indígena Xacriabá, Estado de Minas Gerais / Seroepidemiological survey for infections by fungi causing systemic mycoses in the Xacriabá Indian Reserve, Minas Gerais State, Brazil

Xacriabá Indian Reserve is situated in the north of Minas Gerais State, Brazil, near the municipality of Manga and São Francisco River. The Indian population is miscegenated with caucasian and negroid people and have farming activities. Blood samples were collected from 180 inhabitants of the reserve (85 men and 95 women), 15 to 84 years old. Serum antibodies against antigens of Paracoccidioides brasiliensis, Histoplasma capsulatum, Cryptococcus neoformans, and Candida albicans were tested for by counterimmunoelectrophoresis method. Seropositivity was verified in 5, 3.9, 4.2, and 6.7, respectively of the 180 samples. Those seropositive for antigens of P. brasiliensis and H. capsulatum were predominantly women and had lower age and more elevated mean titers of antibodies than individuals whose sera reacted with antigens of C. neoformans and C. albicans. The results suggest the occurrence of paracoccidioidomycosis-infection and histoplasmosis-infection in the Xacriabá Indian Reserve, particularly in the first decades of life of the inhabitants.

Efeito do tempo de difusao na determinaçao de amonia urinaria pelo metodo de Conway / Effect of the diffusion time on the determination of urinary ammonia throug the Conway method

Estudou-se o efeito do tempo de difusao na determinaçao de amonia urinaria pelo metodo de Conway. Em uma mesma amostra de urina de 24 horas foi determinada a amonia urinaria utilizando-se os seguintes tempos de difusao: 3,6,16,24,30 e 48 horas. a maior quantidade de amonia urinaria foi obtida nos tempos de difusao de 30 e 48 horas. Deste modo e recomendado o controle rigoroso das condiçoes de coleta, acidificaçao e armazenamento da urina, o uso sistematico de curvas de calibraçao com tempo de difusao fixo e predeterminado, levando-se tambem em conta a temperatura ambiente e a diluiçao da urina, para que toda a amonia seja absorvida no menor tempo de difusao