Launched in 1996, NARMS is a U. S. public health surveillance system that tracks antimicrobial susceptibility of select foodborne enteric bacteria. We hear a lot about the growing crisis of antibiotic resistance in human health, but it turns out this is just the most visible place it appears as it moves through our complex modern environment. For example, when intensive farming is used to feed large urban populations, antibiotic resistance can first emerge on farms and gain access to human communities through the food system. One of the key groups on the front lines of monitoring antibiotic resistance from farm…
Cover artwork by Daisy S. Lim It was the first multicellular eukaryotic genome sequenced to apparent completion, but it turns out the Caenorhabditis elegans reference that’s been used as a resource for the past 20 years does not exactly correspond with any N2 strain that exists today. Assembled using sequence data from N2 and CB1392 populations of uncertain lineage grown in at least two different laboratories during the 1980s and 1990s, accuracy of the C. elegans reference genome is limited both by genetic variants and by the limitations of the technology of the time (clone-based Sanger technology). It is believed…
Plasmodium falciparum Malaria is a complicated killer, and efforts to develop effective vaccines have been hindered by gaps in our understanding of both the parasite that causes the infection, Plasmodium falciparum, and its transmitter, the mosquito. Like many virulent parasites, P. falciparum has evaded close genetic scrutiny due to its complex and changing composition. Its 23 Mb haploid genome is extremely AT rich (~80%) and contains stretches of highly repetitive sequences, especially in telomeric and subtelomeric regions. To make matters more complicated, it expands its genetic diversity during mitosis via homologous recombination, leading to the acquisition of new variants of…
They are the unwelcome comeback kids: Measles, mumps and other old-time diseases that were once nearly extinct are on the rise in suburban communities as well as developing nations. In order to better understand the evolution of these microbial menaces, researchers at the Wellcome Sanger Institute and Public Health England have been sequencing historical samples deposited in the UK’s National Collection of Type Cultures (NCTC). The latest is a strain of cholera-causing bacteria (Vibrio cholerae) extracted in 1916 from the stool of a British soldier who was convalescing in Egypt. Researchers at the Sanger Institute revived the WWI soldier’s bacteria…
It’s a murder mystery of massive proportion, albeit on a miniature scale: Male-killing among several species of insects, caused by selfish symbiotic bacteria. Swiss researchers believe they have finally solved a question that has stumped scientists for decades, with potential implications for pest and infection control. Researchers have identified the toxin responsible for selective killing of male fruit flies (left) using PacBio sequencing. In a recent Nature publication, Toshiyuki Harumoto and Bruno Lemaitre of the Global Health Institute at the École Polytechnique Fédérale de Lausanne (EPFL) in Lausanne, Switzerland, have reported their findings regarding a toxin in Spiroplasma poulsonii, one…
Haemophilus influenzae, a sample of which was deposited to the NCTC collection by Alexander Fleming, from his own nose. The genomes of 3,000 strains of bacteria, including some of the deadliest in the world, are now available to researchers as part of an ambitious project by the UK’s National Collection of Type Cultures (NCTC), in partnership with the Wellcome Sanger Institute and PacBio. Plague, cholera, streptomyces, and 250 strains of E. coli, are among the reference genomes created, as well as all ‘type strains’ of the bacteria in the collection — the first strains that describe the species and are…
From CDC/Courtesy of Larry Stauffer, Oregon State Public Health Laboratory Scientists from the University of Hong Kong recently reported results of a head-to-head comparison of long-read and short-read platforms for sequencing and assembly of a bacterial genome. They determined that only SMRT Sequencing was capable of generating highly accurate, complete assemblies. “Completing bacterial genomes should no longer be regarded as a luxury, but rather as a cost-effective necessity,” the team reports. “PacBio But Not Illumina Technology Can Achieve Fast, Accurate and Complete Closure of the High GC, Complex Burkholderia pseudomallei Two-Chromosome Genome” was published in Frontiers in Microbiology by lead author Jade…
A new publication reports the discovery and analysis of a nightmare bacterium that’s genetically resistant to all commercially available classes of antibiotics. The paper, “Stepwise evolution of pandrug-resistance in Klebsiella pneumonia,” came out this month in Scientific Reports from Nature. Lead authors Hosam Zowawi and Brian Forde, along with senior author David Paterson and several collaborators, studied an isolate recovered from the urine of an 87-year-old patient who was hospitalized in the United Arab Emirates last year. They used SMRT Sequencing to characterize the strain and its genetic mechanisms for drug resistance. That strain, MS6671, “was found to be non-susceptible to…
Richard Roberts, Nobel Laureate and Chief Scientific Officer of New England Biolabs, offers his thoughts on the utility of methylation data for understanding prokaryotes. In his words: “Please run SMRT Analysis to detect methylation in your prokaryotic PacBio data. Most bacteria and archaea encode DNA methylases, many of which are known components of restriction-modification systems. Usually, these are quite specific in terms of the sequences they recognize; the restriction component becomes a key defense mechanism preventing phages, plasmids, and other DNA elements from infecting the cell. Until recently, it was quite difficult to determine the recognition sequences of these methylases.…