In all the above analyses, a P value of,0.05 was considered statistically significant

e was a marginal increase in CpxAR Confers b-Lactam Resistance 8 CpxAR Confers b-Lactam Resistance expression of major facilitator type efflux pump kmrA compared to wild type . Complementation of the cpxAR mutation almost restored expression of all the tested genes ” . These results provide evidence for the additional regulatory role of Cpx system on MDR efflux pumps. Discussion Bacteria have numerous different systems for sensing their environment and to respond with alterations in gene expression. Given the significance of the integrity of the cell envelope to bacterial survival, it is known that five different systems which respond to stresses in the cell envelope have been explored. Among these, the CpxAR TCS is conceivably the best characterized. At least two important functions have been ascribed to the Cpx system in enteric bacteria; these include regulating factors that deal with misfolded proteins in the periplasmic space and affecting expression of surface components that mediate attachment to some surfaces. It has also been suggested that the Cpx signaling pathway may play a role in signaling E. coli cells present in biofilms to stop making biofilmrelated adhesins. The signals that activate the Cpx system in E. coli are diverse and include alkaline pH, overexpression of certain proteins, interaction with abiotic surfaces, and others. The Cpx regulon in E. coli has been described as involving 34 operons and at least 50 genes. In this investigation the unprecedented area i.e. its direct involvement in drug resistance has been decoded in K. pneumoniae. The recently sequenced genomic data of K. pneumoniae NTUH-K2044, encoding 4,992 proteins reveals the presence of CpxAR operon in its genome. The operon was disrupted and its effect on general physiology of the pleomorphic bacillus was studied. The R-7128 mucoid slimy nature of cells is indicative of an overproduction of a capsule like polysaccharide in K. pneumoniae, but in our study no significant difference “
10545176“in capsule synthesis between the K. pneumoniae wild-type strain and its cpxAR mutant was detected. It would be worthy to state here that other factors such as the production of exopolysaccharides, pilus synthesis, lipopolysaccharide composition, or the expression of auto transporter proteins, also are responsible for capsule synthesis, thus mere deletion of cpxAR might not be sufficient to see a loss in capsule production. K. pneumoniae is an opportunistic pathogen responsible for many nosocomial infections. Multidrug resistant K. pneumoniae isolates are frequently isolated at an increased frequency, which therefore leads to a therapeutic impasse. The reservoir for K. pneumoniae strain is the GI tract of patients, and GI colonization depends on the ability of the bacteria to adhere to mucosal surfaces, to form biofilm within the mucus layer, and to resist the specific stresses encountered in the GI tract. Epidemiological studies have shown that, whatever the infection site, the first ” stage in nosocomial infections due to K. pneumoniae consists of the colonization in the patient’s GI tract. This pathogen therefore has to sense and respond to numerous different environments in order to survive and, consequently, to persist in the GI tract of the host. The first major barrier encountered following oral consumption is stomach acidity. The bacteria then enter the small intestine, where they encounter stresses associated with volatile fatty acids, variations in pH and osmolarity, and compet