These hypervirulent strains have been associated with increased morbidity and higher mortality.
Susan Secore, Su Wang, Julie Doughtry, Jinfu Xie, Matt Miezeiewski, Richard R. Rustandi,Melanie Horton, Rachel Xoconostle, Bei Wang, Catherine Lancaster, Adam Kristopeit,Sheng-Ching Wang, Sianny Christanti, Salvatore Vitelli, Marie-Pierre Gentile, AaronGoerke, Julie Skinner, Erica Strable, David S. Thiriot, Jean-Luc Bodmer, Jon H. Heinrichs 2017, 'Development of a Novel Vaccine Containing Binary Toxin for the Prevention of Clostridiumdifficile Disease with Enhanced Efficacy against NAP1 Strains', PLOS ONE10.1371/journal.pone.0170640. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Deaths during the 1918–19 influenza pandemic have been attributed to a hypervirulent influenza strain.
John F. Brundage, G. Dennis Shanks 2008, 'Deaths from Bacterial Pneumonia during 1918–19 Influenza Pandemic', Emerging Infectious Diseaseshttps://wwwnc.cdc.gov/eid/article/14/8/07-1313_article. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
These mutants have a wide range of phenotypes, from attenuated to hypervirulent strains.
Farahnaz Movahedzadeh, Rosangela Frita, Hiten J. Gutka 2011, 'A two-step strategy for the complementation of M: tuberculosis mutants', Genetics and Molecular Biologyhttp://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000200020. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Infections due to hypervirulent strains were rare.
Nienke Z Borren, Shadi Ghadermarzi, Susan Hutfless, Ashwin N Ananthakrishnan 2017, 'The emergence of Clostridium difficile infection in Asia: A systematic review andmeta-analysis of incidence and impact.', PLoS ONEhttp://europepmc.org/articles/PMC5413003?pdf=render. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Out of 96 isolates, 39 isolates (40.6%) were identified with hypervirulent phenotypes.
Rambha K. Shah, Zhao H. Ni, Xiao Y. Sun, Guo Q. Wang, Fan Li 2017, 'The Determination and Correlation of Various Virulence Genes, ESBL, Serum BactericidalEffect and Biofilm Formation of Clinical Isolated Classical Klebsiella pneumoniaeand Hypervirulent Klebsiella pneumoniae from Respiratory Tract Infected Patients',Polish Journal of Microbiologyhttps://www.exeley.com/exeley/journals/polish_journal_of_microbiology/66/4/pdf/10.5604_01.3001.0010.7042.pdf. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The hypervirulent strain was present in 54% of the cases.
J.A. Velarde Ruiz-Velasco, J.M. Aldana-Ledesma, M.A. Ibarra-Estrada, S.A. AguirreDíaz, J.A. Fernández-Ramírez, F. Cárdenas-Lara, F. Álvarez López, L.E. Rodríguez-Noriega,H.R. Pérez-Gómez, M.R. Morfín-Otero 2017, 'Clinical and endoscopic features in patients with hospital-acquired diarrhea associatedwith Clostridium difficile infection', Revista de Gastroenterología de México (English Edition)http://www.sciencedirect.com/science/article/pii/S2255534X17300816. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
None of the isolates was hypervirulent.
Chaitra Shankar, Manish Kumar, Ashtawarthani Baskaran, Miracle Magdelene Paul, NithyaPonmudi, Sridhar Santhanam, Joy Sarojini Michael, Balaji Veeraraghavan 2018, 'Molecular characterisation for clonality and transmission dynamics of an outbreakof Klebsiella pneumoniae amongst neonates in a tertiary care centre in South India',Indian Journal of Medical Microbiologyhttp://www.ijmm.org/article.asp?issn=0255-0857;year=2018;volume=36;issue=1;spage=54;epage=60;aulast=Shankar. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Based on this study, we propose that the rapid intracellular growth of hypervirulent mycobacteria results in massive macrophage damage.
Eduardo P Amaral, Simone C M Ribeiro, Verônica R Lanes, Fabrício M Almeida, MarcelleR M de Andrade, Caio Cesar Barbosa Bomfim, Erika M Salles, Karina R Bortoluci, RobsonCoutinho-Silva, Mario H Hirata, José M Alvarez, Elena B Lasunskaia, Maria Regina D'Império-Lima 2014, 'Pulmonary infection with hypervirulent Mycobacteria reveals a crucial role for theP2X7 receptor in aggressive forms of tuberculosis.', PLoS Pathogenshttp://europepmc.org/articles/PMC4081775?pdf=render. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
These results shed light on pathophysiological processes that draw the line between a virulent and ahypervirulent pathogen.
Françoise Guinet, Patrick Avé, Louis Jones, Michel Huerre, Elisabeth Carniel 2008, 'Defective Innate Cell Response and Lymph Node Infiltration Specify Yersinia pestisInfection', PLoS ONE10.1371/journal.pone.0001688. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Protozoa are known to harbor bacterial pathogens, alter their survival in the environment and make them hypervirulent.
Bradley J. Hernlem, Subbarao Venkata Ravva, Chester Zingapan Sarreal 2014, 'Rapid detection of predation of Escherichia coli O157:H7 and sorting of bacterivorousTetrahymena by flow cytometry', Frontiers in Cellular and Infection Microbiologyhttp://journal.frontiersin.org/Journal/10.3389/fcimb.2014.00057/full. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)