A retrospective observational study on the efficacy of colistin by inhalation as compared to parenteral administration for the treatment of nosocomial pneumonia associated with multidrug-resistant Pseudomonas aeruginosa

<p>Abstract</p> <p>Background</p> <p>Colistin is used as last treatment option for pneumonia associated with multidrug-resistant (MDR) <it>Pseudomonas </it>spp.. Literature about the best administration mode (inhalation versus parenteral treatment) is lacking.</p> <p>Methods</p> <p>A retrospective study of 20 intensive care patients with a pneumonia associated with MDR <it>P. aeruginosa </it>receiving colistin sulphomethate sodium (Colistineb^®) between 2007 and 2009 was performed. A strain was considered multidrug-resistant if it was resistant to at least 6 of the following antibiotics: piperacillin-tazobactam, ceftazidime, cefepime, meropenem, aztreonam, ciprofloxacin, and amikacin. The administration mode, predicted mortality based on the SAPS3 score, SOFA score at onset of the colistin treatment, clinical and microbiological response, and mortality during the episode of the infection were analysed. The non parametric Kruskal-Wallis and Fisher's Exact test were used for statistical analysis of respectively the predicted mortality/SOFA score and mortality rate.</p> <p>Results</p> <p>Six patients received colistin by inhalation only, 5 were treated only parenterally, and 9 by a combination of both administration modes. All patients received concomitant beta-lactam therapy. The mean predicted mortalities were respectively 72%, 68%, and 69% (p = 0.91). SOFA scores at the onset of the treatment were also comparable (p = 0.87). Clinical response was favorable in all patients receiving colistin by inhalation (6/6) and in 40% (2/5) of the patients receiving colistin parenterally (p = 0.06). In the patients with colistin administered both via inhalation and parenterally, clinical response was favorable in 78% of the patients (7/9) (p = 0.27 as compared to the treatment group receiving colistin only parenterally). When all patients with inhalation therapy were compared to the group without inhalation therapy, a favorable clinical response was present in respectively 87% and 40% (p = 0.06). In none of the patients, the <it>Pseudomonas </it>spp. was eradicated from the follow-up cultures.</p> <p>All patients in the parenterally treated group died. None of the patients receiving colistin by inhalation, and 3 of 9 patients of the combination group eventually died (p = 0.002 and p = 0.03 respectively as compared to the group receiving colistin only parenterally).</p> <p>Conclusions</p> <p>Aerosolized colistin could be beneficial as adjunctive treatment for the management of pneumonia due to MDR <it>P. aeruginosa</it>.</p

Assessment of Microbial Diversity in Biofilms Recovered from Endotracheal Tubes Using Culture Dependent and Independent Approaches

Ventilator-associated pneumonia (VAP) is a common nosocomial infection in mechanically ventilated patients. Biofilm formation is one of the mechanisms through which the endotracheal tube (ET) facilitates bacterial contamination of the lower airways. In the present study, we analyzed the composition of the ET biofilm flora by means of culture dependent and culture independent (16 S rRNA gene clone libraries and pyrosequencing) approaches. Overall, the microbial diversity was high and members of different phylogenetic lineages were detected (Actinobacteria, beta-Proteobacteria, Candida spp., Clostridia, epsilon-Proteobacteria, Firmicutes, Fusobacteria and gamma-Proteobacteria). Culture dependent analysis, based on the use of selective growth media and conventional microbiological tests, resulted in the identification of typical aerobic nosocomial pathogens which are known to play a role in the development of VAP, e.g. Staphylococcus aureus and Pseudomonas aeruginosa. Other opportunistic pathogens were also identified, including Staphylococcus epidermidis and Kocuria varians. In general, there was little correlation between the results obtained by sequencing 16 S rRNA gene clone libraries and by cultivation. Pyrosequencing of PCR amplified 16 S rRNA genes of four selected samples resulted in the identification of a much wider variety of bacteria. The results from the pyrosequencing analysis suggest that these four samples were dominated by members of the normal oral flora such as Prevotella spp., Peptostreptococcus spp. and lactic acid bacteria. A combination of methods is recommended to obtain a complete picture of the microbial diversity of the ET biofilm

Metabolism of excised embryos of Lupinus luteus L. VII. An electrophoretic analysis of esterases and peroxidases in cultured embryos and normal seedling axes

A rich and active spectrum of esterases (E) exists already in the organs of a dry seed. The isolation of axes from the cotyledons exerts a considerable influence on the pattern of E. In the axial organs of a seedling the spectra and activity become impoverished starting from the 3rd day of culture in the dark. On the other hand in the axial organs isolated from the cotyledons from that moment onwards the spectra become richer and more active, particularily in the root. It appears that the enhancement of spectra in the detached axes is not dependent on the elimination with the cotyledons of a source of inhibitors, since in the cotyledons, until the end of the culture period (12 days), a rich pattern of E is maintained. Peroxidase (P) appears starting from the third day giving impoverished spectra, in general development similar to E. The removal of the seed coat from dry seeds exerts during the first two days of imbibition a strong influence on the spectra of axial and cotyledonary enzyms

Metabolism of excised embryos of Lupinus luteus L. VII. An electrophoretic analysis of esterases and peroxidases in cultured embryos and normal seedling axes

A rich and active spectrum of esterases (E) exists already in the organs of a dry seed. The isolation of axes from the cotyledons exerts a considerable influence on the pattern of E. In the axial organs of a seedling the spectra and activity become impoverished starting from the 3rd day of culture in the dark. On the other hand in the axial organs isolated from the cotyledons from that moment onwards the spectra become richer and more active, particularily in the root. It appears that the enhancement of spectra in the detached axes is not dependent on the elimination with the cotyledons of a source of inhibitors, since in the cotyledons, until the end of the culture period (12 days), a rich pattern of E is maintained. Peroxidase (P) appears starting from the third day giving impoverished spectra, in general development similar to E. The removal of the seed coat from dry seeds exerts during the first two days of imbibition a strong influence on the spectra of axial and cotyledonary enzyms