Influence of prior pandemic A(H1N1)2009 virus infection on invasion of MDCK cells by community-associated methicillin-resistant Staphylococcus aureus.
Secondary bacterial pneumonia due to community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become a highly publicized cause of death associated with influenza. In this study, we performed the gentamicin-killing assay using Madin-Darby canine kidney (MDCK) cells and MRSA strains to investigate whether prior infection from pandemic A(H1N1)2009 virus (A[H1N1]pdm09) lead to increased invasion of MDCK cells by MRSA. We found that the invasion rate of two MRSA strains (ATCC BAA-1680 [USA 300] and ATCC BAA-1699 [USA 100]) into intact MDCK cell monolayers was 0.29 ± 0.15% and 0.007 ± 0.002%, respectively (p < 0.01, n ≥ 3). In addition, the relative invasion rate of both ATCC BAA-1680 and ATCC BAA-1699 was significantly increased by prior A(H1N1)pdm09 infection of MDCK monolayers from 1 ± 0.28 to 1.38 ± 0.02 and from 1 ± 0.24 to 1.73 ± 0.29, respectively (p < 0.01). These results indicate that ATCC BAA-1680 displays much stronger invasiveness of MDCK cells than ATCC BAA-1699, although invasion of both strains was increased by prior A(H1N1)pdm09 infection. In conclusion, this study provided the first evidence that prior A(H1N1)pdm09 infection facilitates the invasion of MDCK cells by MRSA, presumably due to cellular injury caused by the virus.
Department of Infection Control and Prevention, Kitasato University Hospital, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0375, Japan; Research and Development Center for New Medical Frontiers, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan. Electronic address: yoko@med.kitasato-u.ac.jp.
Yoko
Y
Takayama
Department of Infection Control and Laboratory Diagnostics, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai 980-8574, Japan.
Hisakazu
H
Yano
Department of Virology, Kitasato Research Center for Environmental Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0329, Japan.
Yasuhiro
Y
Nojima
Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
Ryuichi
R
Nakano
Department of Microbiology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
Ryoichi
R
Okamoto
Department of Infection Control and Laboratory Diagnostics, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai 980-8574, Japan.
Yoichi
Y
Hirakata
Department of Infection Control and Prevention, Kitasato University Hospital, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0375, Japan.
Keisuke
K
Sunakawa
Department of General Medicine, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
Tohru
T
Akahoshi
Department of Infection Control and Laboratory Diagnostics, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai 980-8574, Japan.
Mitsuo
M
Kaku
D000818:Animals; D017714:Community-Acquired Infections / Q000382:microbiology* / Q000821:virology; D004285:Dogs; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000502:physiology*; D007251:Influenza, Human / Q000382:microbiology* / Q000821:virology; D061985:Madin Darby Canine Kidney Cells; D055624:Methicillin-Resistant Staphylococcus aureus / Q000502:physiology*; D018410:Pneumonia, Bacterial / Q000382:microbiology / Q000821:virology; D013203:Staphylococcal Infections / Q000382:microbiology / Q000821:virology*
A(H1N1)pdm09; Community-associated MRSA; Invasion