Population genomic analyses reveal high diversity, recombination and nosocomial transmission among Candida glabrata (Nakaseomyces glabrata) isolates causing invasive infections.

Candida glabrata is a commensal yeast of the gastrointestinal tract and skin of humans. However, it causes opportunistic infections in immunocompromised patients, and is the second most common Candida pathogen causing bloodstream infections. Although there are many studies on the epidemiology of C. glabrata infections, the fine- and large-scale geographical nature of C. glabrata remain incompletely understood. Here we investigated both the fine- and large-scale population structure of C. glabrata through genome sequencing of 80 clinical isolates obtained from six tertiary hospitals in Qatar and by comparing with global collections. Our fine-scale analyses revealed high genetic diversity within the Qatari population of C. glabrata and identified signatures of recombination, inbreeding and clonal expansion within and between hospitals, including evidence for nosocomial transmission among coronavirus disease 2019 (COVID-19) patients. In addition to signatures of recombination at the population level, both MATa and MATα alleles were detected in most hospitals, indicating the potential for sexual reproduction in clinical environments. Comparisons with global samples showed that the Qatari C. glabrata population was very similar to those from other parts of the world, consistent with the significant role of recent anthropogenic activities in shaping its population structure. Genome-wide association studies identified both known and novel genomic variants associated with reduced susceptibilities to fluconazole, 5-flucytosine and echinocandins. Together, our genomic analyses revealed the diversity, transmission patterns and antifungal drug resistance mechanisms of C. glabrata in Qatar as well as the relationships between Qatari isolates and those from other parts of the world.

Genomic Epidemiology of Carbapenem-Resistant Klebsiella in Qatar: Emergence and Dissemination of Hypervirulent Klebsiella pneumoniae Sequence Type 383 Strains.

The emergence of carbapenem-resistant, hypervirulent Klebsiella pneumoniae is a new threat to health care. We studied the molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae isolates in Qatar using whole-genome sequence data. We also characterized the prevalence and genetic basis of hypervirulent phenotypes and established the virulence potential using a Galleria mellonella model. Of 100 Klebsiella isolates studied, NDM and OXA-48 were the most common carbapenemases. Core genome single-nucleotide polymorphism (SNP) analysis indicated the presence of diverse sequence types and clonal lineages; isolates belonging to Klebsiella quasipneumoniae subsp. quasipneumoniae sequence type 196 (ST196) and ST1416 may be disseminated among several health care centers. Ten K. pneumoniae isolates carried rmpA and/or truncated rmpA2, and 2 isolates belonged to KL2, indicating low prevalence of classical hypervirulent isolates. Isolates carrying both carbapenem resistance and hypervirulence genes were confined mainly to ST231 and ST383 isolates. One ST383 isolate was further investigated by MinION sequencing, and the assembled genome indicated that blaNDM was located on an IncHI1B-type plasmid (pFQ61_ST383_NDM-5) which coharbored several virulence factors, including the regulator of the mucoid phenotype (rmpA), the regulator of mucoid phenotype 2 (rmpA2), and aerobactin (iucABCD and iutA), likely resulting from recombination events. Comparative genomics indicated that this hybrid plasmid may be present in two additional Qatari ST383 isolates. Carbapenem-resistant, hypervirulent K. pneumoniae ST383 isolates pose an emerging threat to global health due to their simultaneous hypervirulence and multidrug resistance.

The first consecutive 5000 patients with Coronavirus Disease 2019 from Qatar; a nation-wide cohort study.

BACKGROUND: There are limited data on Coronavirus Disease 2019 (COVID-19) outcomes at a national level, and none after 60 days of follow up. The aim of this study was to describe national, 60-day all-cause mortality associated with COVID-19, and to identify risk factors associated with admission to an intensive care unit (ICU). METHODS: This was a retrospective cohort study including the first consecutive 5000 patients with COVID-19 in Qatar who completed 60 days of follow up by June 17, 2020. The primary outcome was all-cause mortality at 60 days after COVID-19 diagnosis. In addition, we explored risk factors for admission to ICU. RESULTS: Included patients were diagnosed with COVID-19 between February 28 and April 17, 2020. The majority (4436, 88.7%) were males and the median age was 35 years [interquartile range (IQR) 28-43]. By 60 days after COVID-19 diagnosis, 14 patients (0.28%) had died, 10 (0.2%) were still in hospital, and two (0.04%) were still in ICU. Fatal COVID-19 cases had a median age of 59.5 years (IQR 55.8-68), and were mostly males (13, 92.9%). All included pregnant women (26, 0.5%), children (131, 2.6%), and healthcare workers (135, 2.7%) were alive and not hospitalized at the end of follow up. A total of 1424 patients (28.5%) required hospitalization, out of which 108 (7.6%) were admitted to ICU. Most frequent co-morbidities in hospitalized adults were diabetes (23.2%), and hypertension (20.7%). Multivariable logistic regression showed that older age [adjusted odds ratio (aOR) 1.041, 95% confidence interval (CI) 1.022-1.061 per year increase; P < 0.001], male sex (aOR 4.375, 95% CI 1.964-9.744; P < 0.001), diabetes (aOR 1.698, 95% CI 1.050-2.746; P 0.031), chronic kidney disease (aOR 3.590, 95% CI 1.596-8.079, P 0.002), and higher BMI (aOR 1.067, 95% CI 1.027-1.108 per unit increase; P 0.001), were all independently associated with increased risk of ICU admission. CONCLUSIONS: In a relatively younger national cohort with a low co-morbidity burden, COVID-19 was associated with low all-cause mortality. Independent risk factors for ICU admission included older age, male sex, higher BMI, and co-existing diabetes or chronic kidney disease.