take the gene sequencing data and attempt to define the molecular mechanisms of infection for Pseudomonas aeruginosa. They want to see which genes are needed for survival in its human host and which are needed for drug resistance. Pseudomonas aeruginosa is the largest of the 25 bacteria that scientists have sequenced so far. The largest previously sequenced bacterium was Escherichia coli, which has 4.6 million base pairs and approximately 4,200 genes. Pseudomonas aeruginosa, by contrast, has more than 6 million base pairs and approximately 5,500 genes. Preliminary work suggests that the high number of genes in Pseudomonas aeruginosa allow it to adapt and survive in many different environments, whereas most bacteria live within a small niche. Indoor plumbing, in particular, is especially hospitable to Pseudomonas aeruginosa. Typical disinfectants are not effective at eradicationg it so Pseudomonas aeruginosa can be found on nearly every shower curtain and drain pipe around the world. Functions of Pseudomonas aeruginosa that were previously unknown have been identified, suggesting new avenues for drugs to treat serious lung infections caused by this bacterium. Researchers now have a better understanding of why Pseudomonas aeruginosa is naturally resistant to most antibiotics. As a result, they have new ideas on how to identify antibiotics that might circumvent some of the bacterium’s intrinsic drug resistance mechanisms. The bacterium was sequenced based on one particular organism, or isolate, that is the standard in laboratories. Variations are now being examined that occur when the organism is taken from patients with cystic fibrosis. Scientists are looking for not only how Pseudomonas aeruginosa differs from patient to patient, but what happens to the organism inside the body. “We want to figure out what is different about those clinical isolates, and how these isolates change over time during chronic i...
