A subset of 34 mutants with unique gene disruptions that demonstrated little to no growth on ascites underwent evaluation in a rat subcutaneous abscess model, and these results established that 18 (53%) of these genes could be classed as “in vivo essential”. The putative gene products all had known biological functions, and represented potentially untested, unrecognized, or underexploited targets for antibiotics that could be useful in treating infections in a living host. These genes could be classified into five functional categories: metabolic, two-component signaling systems, DNA/RNA synthesis and regulation, protein transport, and structural. These A. baumannii in vivo essential genes overlapped poorly with the sets of essential genes from other Gram-negative bacteria in the Database of Essential Genes (DEG), including those of Acinetobacter baylyi, a closely related species.
None of the 18 in vivo essential genes identified in this study, or their putative gene products, were classed as targets for currently existing antibiotics. The findings indicate that potentially useful antimicrobials may be developed that will be effective in treating Acinetobacter (or other) infections, though the researchers state that at this time there do not appear to be any FDA-approved antimicrobials or any other drugs in the R&D pipeline that target the newly identified genes.
Umland TC et al. (2012). In Vivo-Validated Essential Genes Identified in Acinetobacter baumannii by Using Human Ascites Overlap Poorly with Essential Genes Detected on Laboratory Media. mBio, 3 (4) PMID: 22911967