Microbial Genomics

We summarize an outbreak of N. gonorrhoeae ST16676 associated with disseminated gonococcal infections (DGIs) in Minnesota, USA in 2025. This novel strain replaced ST11184 as the predominant sequence type circulating among DGI cases in the state, encoded a porB1a allele, and carried a tetracycline resistance gene on a mobilizable plasmid.

Linezolid is a critical last-resort antimicrobial for multidrug-resistant Enterococcus faecium, particularly against vancomycin-resistant lineages where therapeutic options are severely limited. While resistance has historically arisen through de novo chromosomal mutations, the global emergence of transferable resistance mechanisms threatens to render more infections untreatable. Here, we characterise a recent (2023-2024) hospital-associated outbreak of linezolid-resistant E. faecium in Queensla...

BackgroundKlebsiella pneumoniae is a common cause of neonatal sepsis in Africa, and is frequently hospital acquired. We recently reported an outbreak of multidrug-resistant K. pneumoniae sepsis amongst neonates at a rural hospital in The Gambia, West Africa, involving 57 cases and case fatality of 60%. Here we undertook a retrospective pathogen genomic epidemiology study of clinical and environmental K. pneumoniae isolated during the outbreak, to identify the outbreak strain, refine the epidemic...

Klebsiella pneumoniae is a major causative agent of hospital-acquired infections worldwide, contributing substantially to morbidity, mortality, and healthcare burden.. The emergence of strains that combine resistance to last-resort antimicrobials with hypervirulence has become a pressing public-health challenge. Despite extensive characterization of the genetic determinants of multidrug resistance and hypervirulence, the relationship between the genetic repertoire of K. pneumoniae and the clinic...

BackgroundClostridium perfringens can cause life-threatening extraintestinal infections in immunocompromised patients, an area in which we have little information regarding strain factors that impact patient risks and outcomes. MethodsWe conducted genomic-epidemiologic analyses on C. perfringens isolates from 70 patients seen at Brigham and Womens Hospital over 2021-2024. Genomic analyses evaluated strain profiles within a broader context of 2,321 C. perfringens genomes from foodborne, veterina...

BackgroundShigella causes severe diarrheal disease, and S. flexneri and S. sonnei are the targets for multivalent vaccine development. Culture-based agglutination has been the gold standard for serotyping, but it is limited by logistics, subjectivity, and the availability of antisera for emerging serotypes. Newer methods, including a qPCR-based approach and whole-genome sequencing offer alternatives, but their performance in Shigella endemic populations are not well documented. MethodsShigella ...

Campylobacter jejuni is a zoonotic bacterium causing foodborne gastroenteritis in humans worldwide, whose main symptom is diarrhea. The infection is severe mostly in children and in immunocompromised individuals. Currently, the bacterium has become increasingly resistant to antibiotics, especially those first-choice drugs used to treat campylobacteriosis posing a significant health threat towards the treatment outcomes. The burden of campylobacteriosis and Antimicrobial Resistance (AMR) remains ...

BackgroundMycobacterium tuberculosis (Mtb) genomic epidemiology often relies on culturing patient sputum, a time and labor-intensive process. Hybrid capture approaches have been successfully used to enrich Mtb DNA from complex clinical samples, yet the accuracy of variant identification from captured samples has not been systematically evaluated. MethodsWe created artificial strain mixtures of two well-characterized Mtb isolates such that the minor strain comprised 0-50% of Mtb DNA and serially...

BackgroundThe never-ending emergence of superbugs casts a shadow over the victorious age of antibiotics. In fact, the triumph of antibiotics was previously viewed in retrospection as our final victory over bacteria. Bacteria like Klebsiella pneumoniae, Acinetobacter baumannii, and Escherichia coli are now raising an alarming number of infections across hospitals and communities around the globe. The objective was to evaluate the implications for antimicrobial stewardship based on identifying the...

Carbapenem-resistant (CR) bacteria have emerged and been spreading beyond healthcare-associated facilities into the environment. It is recognized that toilet bowl water in patient rooms of healthcare-associated facilities can be one of internal reservoirs of CR bacteria. In accordance with this idea, toilet bowl water samples were collected from patient rooms in a tertiary healthcare-associated facility in North Macedonia, and meropenem (MEM)-resistant bacterial isolates were obtained from the t...

IntroductionSequence-based typing (SBT) has been the standard molecular typing method for understanding Legionella pneumophila genetic relationships. However, genome-scale typing approaches, namely core-genome (cg) or whole-genome (wg) multilocus sequence typing (MLST), provide higher discriminatory power. To advance these capabilities, the Legionella International Typing (LIT) workgroup was established to develop, evaluate, and disseminate a novel cgMLST schema with enhanced wgMLST resolution f...

BackgroundThe effectiveness of current drug-resistant tuberculosis (DR-TB) regimens is limited by the absence of rapid diagnostics that comprehensively predict resistance to included drugs. Next-generation sequencing (NGS), through culture-free targeted sequencing (tNGS) and culture-based whole-genome sequencing (cWGS) of the Mycobacterium tuberculosis complex (MTBC), offers a powerful framework for precision diagnosis, surveillance, and trial applications. We evaluated two novel assays enabling...

Bacterial infections are a major cause of morbidity and mortality among children under five in low- and middle-income countries (LMICs). Children in LMICs are exposed to and colonized by a range of pathogenic bacteria, yet patterns of bacterial exchange between humans are not well known, in part because culturing and sequencing single bacterial isolates is labor-intensive. Here, we apply a machine learning strain tracking approach to metagenomic data from 511 stool samples from children and moth...

BackgroundKlebsiella pneumoniae complex (Kp) is a relevant neonatal pathogen colonizing preterm infants. While outbreak investigations often focus on multidrug-resistant strains, the epidemiology and genomic dynamics of wild-type Kp in nonoutbreak neonatal intensive care unit (NICU) settings remain elusive. MethodsWe conducted a 30-month (October 2021 to March 2024) cohort study with weekly active, unselective colonization surveillance of all NICU patients to identify risk factors for nosocomia...

ObjectiveThe rapid availability of phenotypic antimicrobial susceptibility results is crucial for the timely detection of multidrug-resistant Gram-negative organisms and for guiding optimized treatment strategies. Recently, novel methods have been introduced that enable direct antimicrobial susceptibility testing (AST) from positive blood cultures. However, their performance has not yet been systematically compared in head-to-head evaluations. This study aimed to assess the analytical performanc...

Clostridioides difficile (C. diff) is a leading cause of hospital-acquired infections with severity ranging from mild diarrhea to fulminant colitis and death. Current antigen tests lack adequate sensitivity and DNA-based nucleic acid amplification tests (DNA-NAATs) exhibit limited specificity for active infection, leading to either underdiagnosis or inappropriate treatment of colonized individuals. Unlike DNA, mRNA is expressed only by metabolically active bacteria and is rapidly hydrolyzed, pro...

BackgroundSalmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever, continues to pose a major public health challenge in many low- and middle-income countries (LMICs). The World Health Organization recommended typhoid conjugate vaccine (TCV) use in countries with a high burden of disease, and/or high rates of antimicrobial resistance (AMR). Recent introductions of TCVs into national immunisation programmes are expected to substantially reduce this burden. However, the i...

Understanding host susceptibility to Mycobacterium tuberculosis (Mtb) is critical for the development of new vaccines. Certain individuals "resist" becoming infected with Mtb despite intensive exposure; however, it is unknown whether there is a genetic basis for "resistance" to Mtb infection across populations. Here we conducted a genome-wide association study (GWAS) of resistance to Mtb infection by carefully characterizing exposure to TB patients among 4,058 close contacts in India, Brazil, an...

Shigella flexneri 2a is the most common cause of shigellosis, a major public health concern in developing countries. Rapid and reliable diagnostic tools are critical for timely outbreak detection and management. Leveraging Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology, we developed a CRISPR-Cas12a-based assay for the rapid and specific detection of S. flexneri 2a and validated its performance using stool specimens from patients. Two guide RNAs targeting the gtrII ...

ObjectivesTo quantify how urine sample type and polymicrobial context impact antimicrobial resistance (AMR) in urinary tract infections (UTIs), using routine diagnostics at scale. MethodsIn this retrospective, single-centre study, we analysed 188,687 urine cultures from the Institute of Medical Microbiology, University of Zurich, Switzerland (January 2015 to May 2023). We compared midstream urine (MU), indwelling catheter (IDC), and intermittent catheter (IMC) samples. Samples were classified a...