Sixty-eight Burkholderia cepacia complex isolates recovered from the sputum of 53 cystic fibrosis patients and 75 isolates collected from the maize rhizosphere were compared to each other to assess their genomovar status as well as some traits related to virulence such as antibiotic susceptibility, proteolytic and hemolytic activities, and transmissibility, in which transmissibility is determined by detection of the esmR and cblA genes. Among the clinical isolates, B. cepacia genomovar III comprised the majority of isolates examined and only a very few isolates were assigned to B. cepacia genomovar I, B. stabilis, and B. pyrrocinia; among the environmental isolates a prevalence of B. cepacia genomovar III and B. ambifaria was observed, whereas few environmental isolates belonging to B. cepacia genomovar I and B. pyrrocinia were found. Antibiotic resistance analysis revealed a certain degree of differentiation between clinical and environmental isolates. Proteolytic activity and onion tissue maceration ability were found to be spread equally among both clinical and environmental isolates, whereas larger percentages of environmental isolates than clinical isolates had hemolytic activity. The esmR gene was found exclusively among isolates belonging to B. cepacia genomovar III, with a marked prevalence in clinical isolates, whereas only one clinical isolate belonging to B. cepacia genomovar III was found to bear the cblA gene. In conclusion, the results of the present study show that the species compositions of the clinical and environmental B. cepacia complex populations examined are quite different and that some of the candidate determinants related to virulence and transmissibility are not confined solely to clinical isolates but are also spread among environmental isolates belonging to different species of the B. cepacia complex.

Cellulolytic actinomycetes were isolated from the hindgut of four different termites: Macrotermes, Armitermes, Odontotermes and Microcerotermes spp. The isolated actinomycetes (Streptomyces sp. and Micromonospora sp.) were grown on cellulosic substrates and their extracellular cellulase (Cl, Cx and cellobiase) activity evaluated; using filter paper as a substrate for Cl, carboxymethylcellulose (CMC) for Cx and d‐cellobiose for cellobiase, all strains were shown to degrade soluble and insoluble cellulose; optimum pH for growth was 6.2–6.7 at 28°C; three strains could grow at 48°C on cellulosic substrates. Some strains exhibited high cellulase activity, constant for 5–7 days, but inhibition by glucose was a common feature for almost all isolates.

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We have studied the possibility of an increase in ofloxacin bactericidal activity when it is combined with fresh human serum. The tested strains were 10 clinical isolates of Klebsiella pneumoniae. From among our strains 5 were susceptible to serum bactericidal activity and 5 were found to be resistant. We selected two serum concentrations (15 and 35%) to test against susceptible strains and two (55 and 75%) to test against resistant strains in combination with the minimum inhibitory concentration (MIC), 1/2MIC and 1/4MIC of ofloxacin. The results show a slight variability among the tested strains depending on microbiological characteristics of single strains, however, the serum + ofloxacin combination was advantageous. Only one exception was observed: a resistant strain that had an increased survival percentage against ofloxacin and serum in combination.