​New York, Nov 16 (IANS) Researchers at The Rockefeller University in New York said they discovered two promising new antibiotics by sifting through the human microbiome with the help of a software.

By using computational methods to identify which genes in a microbe's genome ought to produce antibiotic compounds and then synthesising those compounds themselves, they were able to discover the new antibiotics without having to culture a single bacterium, according to a study published in the journal Nature Chemical Biology.

Most antibiotics in use today are based on natural molecules produced by bacteria - and given the rise of antibiotic resistance, there is an urgent need to find more of them.

Yet coaxing bacteria to produce new antibiotics is a tricky proposition. Most bacteria won't grow in the lab. And even when they do, most of the genes that cause them to churn out molecules with antibiotic properties never get switched on.

The Rockefeller University team led by Sean Brady offers a new way to avoid these problems.

The team began by trawling publicly available databases for the genomes of bacteria that reside in the human body.

They then used specialised computer software to scan hundreds of those genomes for clusters of genes that were likely to produce molecules known as non-ribosomal peptides that form the basis of many antibiotics.

They also used the software to predict the chemical structures of the molecules that the gene clusters ought to produce.

The software initially identified 57 potentially useful gene clusters, which the researchers winnowed down to 30.

Brady and his colleagues then used a method called solid-phase peptide synthesis to manufacture 25 different chemical compounds.

By testing those compounds against human pathogens, the researchers successfully identified two closely related antibiotics, which they dubbed humimycin A and humimycin B.

Both are found in a family of bacteria called Rhodococcus -- microbes that had never yielded anything resembling the humimycins when cultured using traditional laboratory techniques.

The humimycins proved especially effective against Staphylococcus and Streptococcus bacteria, which can cause dangerous infections in humans and tend to become resistant to various antibiotics, said the study.