The chances are that while any one particular strain of bacteria may have limits to their ability to cope with a particular antibacterial challenge there will be the potential within a larger bacterial population to meet the challenge.
Tettelin, et al., 2005
Genome analysis of multiple pathogenic isolates of Streptococcus agalactiae: implications for the microbial "pan-genome".
The development of efficient and inexpensive genome sequencing methods has revolutionized the study of human bacterial pathogens and improved vaccine design. Unfortunately, the sequence of a single genome does not reflect how genetic variability drives pathogenesis within a bacterial species and also limits genome-wide screens for vaccine candidates or for antimicrobial targets. We have generated the genomic sequence of six strains representing the five major disease-causing serotypes of Streptococcus agalactiae, the main cause of neonatal infection in humans. Analysis of these genomes and those available in databases showed that the S. agalactiae species can be described by a pan-genome consisting of a core genome shared by all isolates, accounting for approximately 80% of any single genome, plus a dispensable genome consisting of partially shared and strain-specific genes. Mathematical extrapolation of the data suggests that the gene reservoir available for inclusion in the S. agalactiae pan-genome is vast and that unique genes will continue to be identified even after sequencing hundreds of genomes.
The full text of this paper is avilable online.
Bacterial genomes are much more variable than those of vertebrates, especially when taking into account transmissible genetic material such as plasmids which can readily introduce new factors and many potential new interactions for existing factors.
Gene duplication can obviate the problem of a loss of original function while allowing neofunctionalisation of duplicated genes, tis is especially easy with multiple copies of a plasmid present in each bacterium.
So the news is probably bad on the antibacterial resistance front, the bacteria are never going to be finally beaten with our current approaches and may never be.
You may remember from the Chat room the suggestion that screening factors produced from genomic fragments of relatively, or completely, unstudied bacteria has been suggested to be a promising source of novel antibacterial agents. This is using the huge genetic variability of bacteria to our advantage.
TTFN,
WK
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