Methicillin-resistant Staphylococcus aureus (MRSA) is recognized as a worldwide pathogen, and the incidence of community-acquired infections (CA-MRSA) is increased. A virulence factor has been found in most CA-MRSA in...Methicillin-resistant Staphylococcus aureus (MRSA) is recognized as a worldwide pathogen, and the incidence of community-acquired infections (CA-MRSA) is increased. A virulence factor has been found in most CA-MRSA infections, the Panton-Valentin leukocidin (PVL), which causes polymorphonuclear leukocytes lysis and acute uncontrolled inflammation and tissue injury. In this study we investigated the effect of bacterial supernatant of PVL positive or negative strains on airway smooth muscle obtained from rabbit trachea. MRSA that carry the PVL-gene, confirmed by PCR, is cultured on GP agar and colonies were transferred into casein casein yeast extract medium. The culture supernatants were removed after centrifugation and the presence of PVL was confirmed using an immunochromatographic test. Rabbit tracheal ASMC were isolated and incubated with PVL positive or negative bacterial supernatant (1:20 - 1:2000) for 1 - 3 days. The effect of PVL on the ASMC morphology or viability was estimated using microscope observations or indirect immunofluores- cence with anti-Smooth muscle α-actin antibody and Dapi for DNA staining, and Trypan blue staining, respectively. ASMC incubated with PVL exhibit increased cell size, granular cytoplasm, and ruptured nuclei. Furthermore, PVL reduces cell number mainly in ASMC incubated in the presence of 10% FBS, therefore actively proliferating cells. These results show that apart from the known effect of PVL on immune cells and inflammation process, PVL has a direct toxic effect on airway smooth muscle cells.展开更多
Background: The characteristics of Staphylococcus aureus that made it the most important cause of wound infections are environmental spread antimicrobials resistance and virulence. Absence of molecular detection of dr...Background: The characteristics of Staphylococcus aureus that made it the most important cause of wound infections are environmental spread antimicrobials resistance and virulence. Absence of molecular detection of drug resistance and virulence factors in many developing countries limits the epidemiological information. This study conducted to identify PVL virulence gene, and blaOXA-23 and blaOXA-51 drug resistance genes of Staphylococcus aureus isolated from surgical-sites infections (SSIs) and traumatic wounds. Methods: A cross-sectional study was conducted from 2019 to 2021, in which 70 cefepime resistant Staphylococcus aureus were used, the strains were isolated from patients of SSIs and traumatic wounds admitted to the department of General Surgery in Wad Medani Teaching Hospital. Mannitol salt agar was used for primary culture followed by biochemical identification and Kirby Bauer susceptibility testing. Single and multiplex PCR protocols performed for bacterial confirmation and target genes detection. Results: Staphylococcus aureus strains from SSIs constituted 56% (39/70) from which 41% (16/39) possessed PVL gene while 42% (13/31) of wound infections strains were positive for PVL gene. Presence of PVL gene was significantly associated with resistance to meropenem (P. value 0.023) and ceftriaxone (P. value 0.037). blaOXA-23 was significantly detected with resistance to meropenem, augmentin and ceftriaxone. While blaOXA-51 was significantly identified among Staphylococcus aureus strains that showed resistance to meropenem and ciprofloxacin. Conclusion: This is the first study in Sudan that identified blaOXA-23 and blaOXA-51 in Staphylococcus aureus and correlated them to resistance to commonly used antimicrobials. Meropenem resistant Staphylococcus aureus were significantly positive for PVL, blaOXA-23 and baOXA-51 genes.展开更多
文摘Methicillin-resistant Staphylococcus aureus (MRSA) is recognized as a worldwide pathogen, and the incidence of community-acquired infections (CA-MRSA) is increased. A virulence factor has been found in most CA-MRSA infections, the Panton-Valentin leukocidin (PVL), which causes polymorphonuclear leukocytes lysis and acute uncontrolled inflammation and tissue injury. In this study we investigated the effect of bacterial supernatant of PVL positive or negative strains on airway smooth muscle obtained from rabbit trachea. MRSA that carry the PVL-gene, confirmed by PCR, is cultured on GP agar and colonies were transferred into casein casein yeast extract medium. The culture supernatants were removed after centrifugation and the presence of PVL was confirmed using an immunochromatographic test. Rabbit tracheal ASMC were isolated and incubated with PVL positive or negative bacterial supernatant (1:20 - 1:2000) for 1 - 3 days. The effect of PVL on the ASMC morphology or viability was estimated using microscope observations or indirect immunofluores- cence with anti-Smooth muscle α-actin antibody and Dapi for DNA staining, and Trypan blue staining, respectively. ASMC incubated with PVL exhibit increased cell size, granular cytoplasm, and ruptured nuclei. Furthermore, PVL reduces cell number mainly in ASMC incubated in the presence of 10% FBS, therefore actively proliferating cells. These results show that apart from the known effect of PVL on immune cells and inflammation process, PVL has a direct toxic effect on airway smooth muscle cells.
文摘Background: The characteristics of Staphylococcus aureus that made it the most important cause of wound infections are environmental spread antimicrobials resistance and virulence. Absence of molecular detection of drug resistance and virulence factors in many developing countries limits the epidemiological information. This study conducted to identify PVL virulence gene, and blaOXA-23 and blaOXA-51 drug resistance genes of Staphylococcus aureus isolated from surgical-sites infections (SSIs) and traumatic wounds. Methods: A cross-sectional study was conducted from 2019 to 2021, in which 70 cefepime resistant Staphylococcus aureus were used, the strains were isolated from patients of SSIs and traumatic wounds admitted to the department of General Surgery in Wad Medani Teaching Hospital. Mannitol salt agar was used for primary culture followed by biochemical identification and Kirby Bauer susceptibility testing. Single and multiplex PCR protocols performed for bacterial confirmation and target genes detection. Results: Staphylococcus aureus strains from SSIs constituted 56% (39/70) from which 41% (16/39) possessed PVL gene while 42% (13/31) of wound infections strains were positive for PVL gene. Presence of PVL gene was significantly associated with resistance to meropenem (P. value 0.023) and ceftriaxone (P. value 0.037). blaOXA-23 was significantly detected with resistance to meropenem, augmentin and ceftriaxone. While blaOXA-51 was significantly identified among Staphylococcus aureus strains that showed resistance to meropenem and ciprofloxacin. Conclusion: This is the first study in Sudan that identified blaOXA-23 and blaOXA-51 in Staphylococcus aureus and correlated them to resistance to commonly used antimicrobials. Meropenem resistant Staphylococcus aureus were significantly positive for PVL, blaOXA-23 and baOXA-51 genes.
