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Nos últimos 30 anos, Acinetobacter tornou-se um dos patógenos de maior preocupação clínica pela falta de terapias eficazes em virtude do fenótipo de multirresistência frequentemente apresentado. Dentre as espécies do gênero Acinetobacter, A. baumannii, A. genoespécie 3 e A. genoespécie 13TU são as mais comumente encontradas a partir de amostras biológicas. Estas espécies ao lado de A. calcoaceticus constituem o complexo A. calcoaceticus-A. baumannii (ACB). Este estudo propõe um esquema composto de duas PCRs para a identificação das espécies de interesse médico que fazem parte do complexo ACB. O método é simples, rápido e, além de identificar as espécies, permite pesquisar a presença de genes de resistência. Foram identificadas 515 amostras do complexo ACB, isoladas de pacientes no período de janeiro de 2005 a dezembro de 2010. A identificação das espécies do complexo ACB foi realizada por esquema composto de duas reações de PCR. Foram avaliados os perfis de sensibilidade por disco difusão e a pesquisa da presença dos genes blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, blaOXA-58-like, blaIMP, blaVIM, blaSIM, blaSPM e blaGIM foi realizada por PCR utilizando-se iniciadores específicos. No grupo de amostras estudas, 82,5% são A. baumannii (425), 11,5% A. genoespécie 13TU (59) e 6,0% A. genoespécie 3 (30), sendo A. baumannii mais isolado em pacientes internados em UTIs (p=0,0407) e A. genoespécie 13TU mais isolado em pacientes de outros ambientes hospitalares (p=0,0204). A. baumannii apresentou menor sensibilidade a todos os antimicrobianos quando comparado com A. genoespécie 13TU e A. genoespécie. 3 (p<0,05). Foi possível observar ao longo do período estudado o aumento significativo da resistência aos carbapenêmicos e da sensibilidade a gentamicina por A. baumannii entre os isolados de pacientes de UTIs (p<0.05). Nenhum dos genes codificadores para metalo-lactamases foi detectado nas amostras estudadas Dentre os cepas resistentes aos carbapenêmico...

The genus Acinetobacter has emerged as one of the most troublesome pathogens for health care institutions globally. Its clinical significance, especially over the last 15 years, has been driven by its remarkable ability to up regulate or acquire resistance determinants, making it one of the organisms threatening the current antibiotic era. A. baumannii, A. 3 and A. 13TU are the most commonly species found from biological samples. These species beside A. calcoaceticus are very closely related and difficult to distinguish from each other by phenotypic properties. Therefore, it has been proposed to refer to these species as the A.calcoaceticus-A. baumannii complex(ACB). In the period from 2005 to 2009, the most frequent bacterial isolates among the nosocomial infection at the HU-USP was ACB (18%). Due to the frequency with which species are involved in ACB outbreaks of infection in the HU-USP and the emergency clinic because of expression of the phenotype of resistance to several classes of antibiotics, this study aimed to identify and characterize the species of complex ACB by molecular methods, to study their mechanisms of resistance and to characterize the different clones from patients admitted to different hospital areas. Furthermore, the ability to characterize biofilm formation, adhesion to different cell lines as well as the mechanisms of cell-cell communication were analyzed. From the ACB complex, 515 samples were identified, isolated from patients from January 2005 to December 2010. The identification of clinical species of the ACB was performed by molecular methods that were developed and validated for identification of Acinetobacter sp. include two reactions of PCR. The profiles of sensibility were evaluated by disc diffusion and the detection of the presence of genes blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, blaOXA-58-like, blaIMP, blaVIM, blaSIM, blaGIM, and blaSPM were performed using specific primers. Molecular typing was performed using...

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Acinetobacter calcoaceticus BD413 produces variable amounts of an exocellular lipase that becomes rapidly inactivated upon secretion. To achieve high yield and protect the enzyme, we assayed the addition of several inert compounds to cell-free supernatants, cell fractions, and whole cultures. Glass beads, poly(ethylene glycol) 600, Triton X-100, saccharose, gum arabic, and beta-cyclodextrin were among the compounds tested. beta-Cyclodextrin and gum arabic (and saccharose to a lesser extent) were effective enzyme stabilizers in cell-free supernatants, while gum arabic, glass beads, and Triton X-100 improved lipase secretion from cells, and, therefore, total lipase yield (30-50%, according to the additive). In whole cultures, beta-cyclodextrin was the most effective additive, particularly in combination with glass beads or gum arabic. Indeed, cultures containing beta-cyclodextrin plus gum arabic were able to maintain 95% (+/- 1.5%) of the initial lipase activity for more than 16 h, while control cultures with no additives maintained only 10% (+/- 4%) of the enzyme activity after the same period. In conclusion, the addition of inert compounds in cultures may be considered a useful approach for achieving increased yield and lipase stabilization, amenable for downstream processing.

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Acinetobacter calcoaceticus BD413 was examined for production of siderophores and iron-repressible outer membrane proteins following growth in iron-restricted media. The iron-scavenging phenotype was associated with the secretion of iron-repressible catechol and the induction of a group of six outer membrane proteins with molecular weights ranging from 34 to 85 kDa. The amount of catechol produced was dependent on medium composition and iron stringency. The relation between iron limitation and lipase production was studied at the level of lipA transcription and extracellular lipase activity. In minimal medium, iron limitation slightly affected lipA expression but decreased exo-lipase activity significantly. However, if iron limitation and rich nitrogen sources were simultaneously present in the culture media, the production of lipase was increased approximately 4 times.

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Se describen 11 casos de peritonitis en pacientes sometidos a diálisis peritoneal ambulatoria continua (CAPD) causados por Acinetobacter calcoaceticus en un grupo de 129 pacientes durante 2784 meses. El Acinetobacter calcoaceticus fue responsable de 6.4 por ciento de los 172 episodios de peritonitis registrados durante el período de seguimiento. Se registraron síntomas sistémicos con fiebre,náuseas, vómito y líquido hemático de dializado en 10 casos. La respuesta al tratamiento fue pobre y en cinco (45 por ciento) fue necesario retirar el catéter de diálisis por la falta de respuesta al tratamiento.En seis casos se demostró la presencia de un segundo germen durante la evolución de la peritonitis por Acinetobacter calcoaceticus, en tres Candida albicans, Hafnia alvei, Pseusomonas aeruginosa y Staphylococcus aureus en un caso cada uno. Los 11 episodios de peritonitis causaron 82 días de hospitalización en siete pacientes. La sensibilidad a los antibióticos fue pobre, ninguno sensible a ampicilina, entre las cefalosporinas sólo la ceftazidima fue eficaz in vitro; la amicacina, latobramicina y las quinolonas, mostraron aceptable cubrimiento contra el Acinetobacter calcoaceticus. Comparativamente con otras peritonitis registradas en el grupo, ésta en promedio más días de hospitalización y retiros de catéter de diálisis por falta de respuesta, siendo superada sólo por la causada por Candida albicans. La asociación con otros gérmenes merece mayor investigación, al igual que se debe tratar de comprender mejor la colonización del orificio de salida del catéter por Acinetobacter calcoaceticus, un germen capaz de producir una peritonitis severa y en muchos casos conduce al paciente a ser retirado del programa de CAPD por falla en el tratamiento

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