The median CI value obtained for bladder samples showed that CFU counts for KR2107∆fim and KR2107∆fim∆fim2 did not differ significantly

(Figure 8A). However, the median kidney CFU counts were 5.6-fold higher for the KR2107∆fim (1.4 × 102) than KR2107∆fim∆fim2 mutant (2.5 × 101), and although similar to the results obtained in the fim-positive background these selleck kinase inhibitor results were also not statistically significant (P = 0.066) (Figure 8B). These results have confirmed the importance of fim in K. pneumoniae-mediated urovirulence and further support the case for a potential but subtle accessory role for fim2 in this disease process. Discussion The plastic nature of K. pneumoniae genomes is well described and an increasing number of studies have elucidated the function of various components of the accessory Selleck MLN8237 genome of the pyogenic liver abscess-associated strain K. pneumoniae NTUH-K2044. However, functional characterization of the accessory genome of strains associated with other types of infection is lacking. In order to investigate LY2874455 chemical structure the plasticity of K. pneumoniae associated with other infections, we previously interrogated the pheV locus of sixteen clinical isolates from patients without pyogenic liver abscesses for the presence of foreign DNA elements [13]. In this study, further tRIP-PCR

interrogation of K. pneumoniae KR116 using met56-specific primers identified a novel GI, KpGI-5, inserted within its met56 gene. KR116 had been isolated from the blood of a patient with pneumonia and neutropenic septicaemia. KpGI-5 was sequenced in this study and found to encode a putative γ1-type CU fimbrial operon that has been named fim2. The genetic organization of fim2 resembles that of the K. pneumoniae fim operon and contains homologs of all eight fim genes. fim2 is predicted to code for a major fimbrial subunit (Fim2A), three minor fimbrial subunits (Fim2F, Fim2G, Fim2H) and homologs of the FimC and FimD chaperone and usher proteins, respectively, thus classifying this locus as a novel γ1-type CU operon that putatively encodes a fimbrial appendage [20]. A seventh predicted protein, Fim2I, exhibited 82% identity

to FimI, a protein required for fimbrial biogenesis; however, the exact nature of this dependence Methamphetamine remains unknown [42]. Amino acid sequences of the eight fim2 gene products showed 60 to 92% identity to cognate Fim proteins. Indeed, the two clusters would appear to be pseudoparalogs, homologs that appear to be paralogous but have ended up in the same genome by both vertical and horizontal gene transfer [43]. The unique evolutionary origins of the fim and fim2 cluster are further highlighted by differences in transcriptional control. The fim cluster is largely controlled by the FimB and FimE recombinases which together switch transcription on and off by inverting a 314 bp promoter-containing sequence called fimS that lies upstream of fimA[22].