Six other primer combinations were tried with isolates 41,

Bindarit purchase 54, 55 and 72, however a pilA amplicon was generated only from isolate 72 using primers pilA and tRNAThr, showing that it belonged to TFP group V (tfpZ). Of the 17 isolates for which pilA presence was confirmed only 7 (41%) actually exhibited twitching motility, demonstrating that the presence of pilA alone does not secure motility. Representative amplicons were cloned and sequenced and subsequent alignments confirmed their categorisation into the groups described by Kus et al. [31]. The fliC structural gene was also detected in all 20 isolates (Table 4), however its presence, like that of pilA, did not guarantee swimming motility as 9 isolates (45%) did not swim. The presence of flagella in isolates was verified with SEM, while full length DNA sequences were obtained for fliC of isolates 1, 40, 41 (motile) and 48 (non motile). Statistical

analysis shows that motility contributes to biofilm thickness but not to biofilm formation in our isolates It has been reported in a number of studies [16, 25, 35, 36] that motility is required for biofilm formation, whereas in contrast, Klausen et al. [28] reported that mutants deficient in pili and flagella showed no significant differences from wild type. In the current study, biofilm formation was not influenced by the presence of either flagella or type IV pili, since 45 isolates that Volasertib ic50 formed either moderate or strong biofilms were deficient in twitching, swimming, and swarming motility. In contrast however, isolates 5, 6, and 61 (motile) exhibited very poor adhesion in microtitre plates. For the statistical analysis we started with the null hypothesis that motility does not affect biofilm formation and performed a one-way ANOVA that gave an F-value of 9.88, Dichloromethane dehalogenase allowing rejection of the null hypothesis. At this point we could not say between which groups the difference was so we performed a Tukey’s post-hoc test between all the possible group pairs. Group C1, as it

was termed for the analysis, contained the highest percentage of strong biofilm forming isolates – 80% – while in groups C2 and C3 the percentage of strong biofilm forming isolates was only 40% and 33%, respectively (Fig. 2). The results revealed that C1 was different from C2, C3 and C4 but there was no difference among the C2, C3 and C4. The same conclusion was reached using a Ttest with correction for multiple testing. We this website concluded therefore that the combination of swimming and twitching motility has a positive contribution to biofilm biomass but is not absolutely necessary for the initiation of the process. Figure 2 Box-and-whiskers plots showing the impact of flagella/TFP on the biofilm. P. aeruginosa isolates placed in four groups based on their motility properties. Based on the presence of flagella/TFP the groups were named as C1 (+/+), C2 (-/-), C3 (+/-), C4 (-/+).