Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Morris JM[original query] |
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Inter-species gene flow drives ongoing evolution of Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis
Xie O , Morris JM , Hayes AJ , Towers RJ , Jespersen MG , Lees JA , Ben Zakour NL , Berking O , Baines SL , Carter GP , Tonkin-Hill G , Schrieber L , McIntyre L , Lacey JA , James TB , Sriprakash KS , Beatson SA , Hasegawa T , Giffard P , Steer AC , Batzloff MR , Beall BW , Pinho MD , Ramirez M , Bessen DE , Dougan G , Bentley SD , Walker MJ , Currie BJ , Tong SYC , McMillan DJ , Davies MR . Nat Commun 2024 15 (1) 2286 Streptococcus dysgalactiae subsp. equisimilis (SDSE) is an emerging cause of human infection with invasive disease incidence and clinical manifestations comparable to the closely related species, Streptococcus pyogenes. Through systematic genomic analyses of 501 disseminated SDSE strains, we demonstrate extensive overlap between the genomes of SDSE and S. pyogenes. More than 75% of core genes are shared between the two species with one third demonstrating evidence of cross-species recombination. Twenty-five percent of mobile genetic element (MGE) clusters and 16 of 55 SDSE MGE insertion regions were shared across species. Assessing potential cross-protection from leading S. pyogenes vaccine candidates on SDSE, 12/34 preclinical vaccine antigen genes were shown to be present in >99% of isolates of both species. Relevant to possible vaccine evasion, six vaccine candidate genes demonstrated evidence of inter-species recombination. These findings demonstrate previously unappreciated levels of genomic overlap between these closely related pathogens with implications for streptococcal pathobiology, disease surveillance and prevention. |
The relationship between previous antimicrobial use, antimicrobial resistance and treatment outcome among Alaskans treated for Helicobacter pylori infection
Bruce MG , Bruden D , Newbrough D , Hurlburt DA , Hennessy TW , Morris JM , Reasonover AL , Sacco F , McMahon BJ . GastroHep 2019 1 (4) 172-179 Background: Helicobacter pylori isolates from Alaska have demonstrated a high prevalence of antimicrobial resistance. Objective(s): To determine treatment failure in three groups, and analyse the relationship between treatment failure and antimicrobial resistance. Method(s): Antimicrobial susceptibility was determined using agar dilution and Etest. Treatment success was determined using the urea breath test 2 months after antimicrobial therapy. Result(s): Among 303 treated adult patients, 103 (34%) failed initial treatment despite a 91% compliance with medication. About 222 (73%) patients were treated with a clarithromycin-based regimen, 55 (18%) with a metronidazole-based regimen, 15 (5%) with a regimen that contained clarithromycin and metronidazole and 11 (4%) with other antimicrobials. Among 260 culture-positive patients, 156 (60%) were infected with metronidazole-resistant isolates, 74 (28%) clarithromycin-resistant, 52 (20%) clarithromycin/metronidazole-resistant, 40 (15%) levofloxacin-resistant, 11 (4%) clarithromycin/metronidazole/levofloxacin-resistant and nine (3%) amoxicillin-resistant. Overall, 34% of patients were treated with at least one antibiotic to which their infecting organism was resistant. Among patients treated with clarithromycin-based regimens, treatment failed in 72% of patients carrying clarithromycin-resistant H pylori vs 20% with clarithromycin-sensitive strains (RR = 3.7, P < 0.001). Among patients treated with metronidazole-based regimens, treatment failed in 19% of patients carrying metronidazole-resistant H pylori vs 24% with metronidazole-sensitive strains (P = 0.72). Conclusion(s): A high proportion of H pylori isolates demonstrate resistance to clarithromycin, metronidazole or levofloxacin. Over one third of H pylori-infected patients were treated with an antibiotic to which their infecting organism demonstrated resistance. Clarithromycin resistance is associated with a greater risk for failure with clarithromycin-based multidrug regimens compared to clarithromycin-sensitive; resistance to metronidazole did not affect treatment failure. |
Reinfection after successful eradication of Helicobacter pylori in three different populations in Alaska
Bruce MG , Bruden DL , Morris JM , Reasonover AL , Sacco F , Hurlburt D , Hennessy TW , Gove J , Parkinson A , Sahagun G , Davis P , Klejka J , McMahon BJ . Epidemiol Infect 2014 143 (6) 1-11 We performed a study to determine rates of reinfection in three groups followed for 2 years after successful treatment: American Indian/Alaska Native (AI/AN) persons living in urban (group 1) and rural (group 2) communities, and urban Alaska non-Native persons (group 3). We enrolled adults diagnosed with H. pylori infection based on a positive urea breath test (13C-UBT). After successful treatment was documented at 2 months, we tested each patient by 13C-UBT at 4, 6, 12 and 24 months. At each visit, participants were asked about medication use, illnesses and risk factors for reinfection. We followed 229 persons for 2 years or until they became reinfected. H. pylori reinfection occurred in 36 persons; cumulative reinfection rates were 14.5%, 22.1%, and 12.0% for groups 1, 2, and 3, respectively. Study participants who became reinfected were more likely to have peptic ulcer disease (P = 0.02), low education level (P = 0.04), or have a higher proportion of household members infected with H. pylori compared to participants who did not become reinfected (P = 0.03). Among all three groups, reinfection occurred at rates higher than those reported for other US populations (<5% at 2 years); rural AI/AN individuals appear to be at highest risk for reinfection. |
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