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Abstract
Discussion Forum (0)
Abstract number: 1409

Session Type: 1,5-hour Oral Session

Session Title: 1,5-hour Oral Session

Authors(s): V.O. Baede (1), M.M. Voet (2), T.J.K. Van Der Reijden (2), A. Van Wengen (2), D.E. Horst-Kreft (1), N.A. Lemmens-Den Toom (1), M. Tavakol (1), M.C. Vos (1), P.H. Nibbering (2), W.J.B. Van Wamel (1)

Authors Affiliations(s): (1) Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center Rotterdam, Netherlands, (2) Department of Infectious Diseases, Leiden University Medical Center, Netherlands

Third Party Affiliation: On behalf of the MACOTRA consortium

Background:

Host-pathogen interaction likely plays a role in the epidemiological success of methicillin-resistant Staphylococcus aureus (MRSA) clusters. The ability of MRSA to form biofilm on skin and penetrate tissues poses a serious threat to public health. To obtain insight into the factors involved in the epidemiological success of MRSA, we compared biofilm formation and host and bacterial responses upon exposure of epidermal models to epidemic and nonepidemic MRSA.

Methods:

Twenty-seven epidemic and thirty-one nonepidemic MRSA strains of different genetic backgrounds were used to infect air-exposed 3D N/TERT-based epidermal models (NEMs). NEMs were exposed to 5,61 log CFU/NEM (SD=0,38) MRSA and the number of adherent bacteria on NEMs and non-adherent bacteria in the subnatants were determined after 1, 2 and 8 days. In addition, the expression of 43 S. aureus virulence factors, inflammatory cytokines (IL-1β, IL-6 and IL-8) and host defense peptides (hBD-2 and RNase-7) was assessed using immunoassays.

Results:

Mean log CFU/NEM decreased from 8,17 (SD=0,75) at 24h to 7,73 (SD=0,51) at 8 days after inoculation. Epidemiological success did not significantly affect bacterial survival after 8 days (7,79 (SD=0,47) log CFU/NEM for epidemic strains and 7,69 (SD=0,54) log CFU/NEM for nonepidemic strains (W=6421,5; p=0,29)). Expression of IL-1β, IL-8, hBD-2 and RNase-7 increased during infection, but no differences were found between epidemic and nonepidemic strains. Skin infection was associated with expression of toxins alpha-toxin (hla) and gamma-hemolysin B (HlgB), thermonuclease (Nuc), extracellular adherence proteins EapH1 and EapH2 and autolysins Atl2 and Aly. No differences between epidemic and nonepidemic strains were found in the expression of virulence factors. Two days after inoculation, penetration of keratinocyte layers and the underlying filter occurred in 78% of samples. One day after inoculation, this was most frequent in epidemic isolates of CC8 (63%) and CC5 (50%) opposed to epidemic isolates of CC22 (17%) and CC30 (20%).

Conclusions:

This study shows the great ability of MRSA to form biofilms on human skin and penetrate the epidermis, irrespective of epidemiological success. Skin infection was associated with a specific profile of S. aureus virulence factors. Interestingly, penetration of the keratinocyte layers was more prominent in epidemic isolates of CC5 and CC8.

Keyword(s): Staphylococcus aureus, keratinocyte, skin infection

Abstract number: 1409

Session Type: 1,5-hour Oral Session

Session Title: 1,5-hour Oral Session

Authors(s): V.O. Baede (1), M.M. Voet (2), T.J.K. Van Der Reijden (2), A. Van Wengen (2), D.E. Horst-Kreft (1), N.A. Lemmens-Den Toom (1), M. Tavakol (1), M.C. Vos (1), P.H. Nibbering (2), W.J.B. Van Wamel (1)

Authors Affiliations(s): (1) Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center Rotterdam, Netherlands, (2) Department of Infectious Diseases, Leiden University Medical Center, Netherlands

Third Party Affiliation: On behalf of the MACOTRA consortium

Background:

Host-pathogen interaction likely plays a role in the epidemiological success of methicillin-resistant Staphylococcus aureus (MRSA) clusters. The ability of MRSA to form biofilm on skin and penetrate tissues poses a serious threat to public health. To obtain insight into the factors involved in the epidemiological success of MRSA, we compared biofilm formation and host and bacterial responses upon exposure of epidermal models to epidemic and nonepidemic MRSA.

Methods:

Twenty-seven epidemic and thirty-one nonepidemic MRSA strains of different genetic backgrounds were used to infect air-exposed 3D N/TERT-based epidermal models (NEMs). NEMs were exposed to 5,61 log CFU/NEM (SD=0,38) MRSA and the number of adherent bacteria on NEMs and non-adherent bacteria in the subnatants were determined after 1, 2 and 8 days. In addition, the expression of 43 S. aureus virulence factors, inflammatory cytokines (IL-1β, IL-6 and IL-8) and host defense peptides (hBD-2 and RNase-7) was assessed using immunoassays.

Results:

Mean log CFU/NEM decreased from 8,17 (SD=0,75) at 24h to 7,73 (SD=0,51) at 8 days after inoculation. Epidemiological success did not significantly affect bacterial survival after 8 days (7,79 (SD=0,47) log CFU/NEM for epidemic strains and 7,69 (SD=0,54) log CFU/NEM for nonepidemic strains (W=6421,5; p=0,29)). Expression of IL-1β, IL-8, hBD-2 and RNase-7 increased during infection, but no differences were found between epidemic and nonepidemic strains. Skin infection was associated with expression of toxins alpha-toxin (hla) and gamma-hemolysin B (HlgB), thermonuclease (Nuc), extracellular adherence proteins EapH1 and EapH2 and autolysins Atl2 and Aly. No differences between epidemic and nonepidemic strains were found in the expression of virulence factors. Two days after inoculation, penetration of keratinocyte layers and the underlying filter occurred in 78% of samples. One day after inoculation, this was most frequent in epidemic isolates of CC8 (63%) and CC5 (50%) opposed to epidemic isolates of CC22 (17%) and CC30 (20%).

Conclusions:

This study shows the great ability of MRSA to form biofilms on human skin and penetrate the epidermis, irrespective of epidemiological success. Skin infection was associated with a specific profile of S. aureus virulence factors. Interestingly, penetration of the keratinocyte layers was more prominent in epidemic isolates of CC5 and CC8.

Keyword(s): Staphylococcus aureus, keratinocyte, skin infection

Epidemic and non-epidemic MRSA do not differ in their interaction with N/TERT-based epidermal models
Valérie O. Baede
Valérie O. Baede
ESCMID eAcademy. Baede V. 07/09/2021; 333014; 1409;
user
Valérie O. Baede
Abstract
Discussion Forum (0)
Abstract number: 1409

Session Type: 1,5-hour Oral Session

Session Title: 1,5-hour Oral Session

Authors(s): V.O. Baede (1), M.M. Voet (2), T.J.K. Van Der Reijden (2), A. Van Wengen (2), D.E. Horst-Kreft (1), N.A. Lemmens-Den Toom (1), M. Tavakol (1), M.C. Vos (1), P.H. Nibbering (2), W.J.B. Van Wamel (1)

Authors Affiliations(s): (1) Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center Rotterdam, Netherlands, (2) Department of Infectious Diseases, Leiden University Medical Center, Netherlands

Third Party Affiliation: On behalf of the MACOTRA consortium

Background:

Host-pathogen interaction likely plays a role in the epidemiological success of methicillin-resistant Staphylococcus aureus (MRSA) clusters. The ability of MRSA to form biofilm on skin and penetrate tissues poses a serious threat to public health. To obtain insight into the factors involved in the epidemiological success of MRSA, we compared biofilm formation and host and bacterial responses upon exposure of epidermal models to epidemic and nonepidemic MRSA.

Methods:

Twenty-seven epidemic and thirty-one nonepidemic MRSA strains of different genetic backgrounds were used to infect air-exposed 3D N/TERT-based epidermal models (NEMs). NEMs were exposed to 5,61 log CFU/NEM (SD=0,38) MRSA and the number of adherent bacteria on NEMs and non-adherent bacteria in the subnatants were determined after 1, 2 and 8 days. In addition, the expression of 43 S. aureus virulence factors, inflammatory cytokines (IL-1β, IL-6 and IL-8) and host defense peptides (hBD-2 and RNase-7) was assessed using immunoassays.

Results:

Mean log CFU/NEM decreased from 8,17 (SD=0,75) at 24h to 7,73 (SD=0,51) at 8 days after inoculation. Epidemiological success did not significantly affect bacterial survival after 8 days (7,79 (SD=0,47) log CFU/NEM for epidemic strains and 7,69 (SD=0,54) log CFU/NEM for nonepidemic strains (W=6421,5; p=0,29)). Expression of IL-1β, IL-8, hBD-2 and RNase-7 increased during infection, but no differences were found between epidemic and nonepidemic strains. Skin infection was associated with expression of toxins alpha-toxin (hla) and gamma-hemolysin B (HlgB), thermonuclease (Nuc), extracellular adherence proteins EapH1 and EapH2 and autolysins Atl2 and Aly. No differences between epidemic and nonepidemic strains were found in the expression of virulence factors. Two days after inoculation, penetration of keratinocyte layers and the underlying filter occurred in 78% of samples. One day after inoculation, this was most frequent in epidemic isolates of CC8 (63%) and CC5 (50%) opposed to epidemic isolates of CC22 (17%) and CC30 (20%).

Conclusions:

This study shows the great ability of MRSA to form biofilms on human skin and penetrate the epidermis, irrespective of epidemiological success. Skin infection was associated with a specific profile of S. aureus virulence factors. Interestingly, penetration of the keratinocyte layers was more prominent in epidemic isolates of CC5 and CC8.

Keyword(s): Staphylococcus aureus, keratinocyte, skin infection

Abstract number: 1409

Session Type: 1,5-hour Oral Session

Session Title: 1,5-hour Oral Session

Authors(s): V.O. Baede (1), M.M. Voet (2), T.J.K. Van Der Reijden (2), A. Van Wengen (2), D.E. Horst-Kreft (1), N.A. Lemmens-Den Toom (1), M. Tavakol (1), M.C. Vos (1), P.H. Nibbering (2), W.J.B. Van Wamel (1)

Authors Affiliations(s): (1) Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center Rotterdam, Netherlands, (2) Department of Infectious Diseases, Leiden University Medical Center, Netherlands

Third Party Affiliation: On behalf of the MACOTRA consortium

Background:

Host-pathogen interaction likely plays a role in the epidemiological success of methicillin-resistant Staphylococcus aureus (MRSA) clusters. The ability of MRSA to form biofilm on skin and penetrate tissues poses a serious threat to public health. To obtain insight into the factors involved in the epidemiological success of MRSA, we compared biofilm formation and host and bacterial responses upon exposure of epidermal models to epidemic and nonepidemic MRSA.

Methods:

Twenty-seven epidemic and thirty-one nonepidemic MRSA strains of different genetic backgrounds were used to infect air-exposed 3D N/TERT-based epidermal models (NEMs). NEMs were exposed to 5,61 log CFU/NEM (SD=0,38) MRSA and the number of adherent bacteria on NEMs and non-adherent bacteria in the subnatants were determined after 1, 2 and 8 days. In addition, the expression of 43 S. aureus virulence factors, inflammatory cytokines (IL-1β, IL-6 and IL-8) and host defense peptides (hBD-2 and RNase-7) was assessed using immunoassays.

Results:

Mean log CFU/NEM decreased from 8,17 (SD=0,75) at 24h to 7,73 (SD=0,51) at 8 days after inoculation. Epidemiological success did not significantly affect bacterial survival after 8 days (7,79 (SD=0,47) log CFU/NEM for epidemic strains and 7,69 (SD=0,54) log CFU/NEM for nonepidemic strains (W=6421,5; p=0,29)). Expression of IL-1β, IL-8, hBD-2 and RNase-7 increased during infection, but no differences were found between epidemic and nonepidemic strains. Skin infection was associated with expression of toxins alpha-toxin (hla) and gamma-hemolysin B (HlgB), thermonuclease (Nuc), extracellular adherence proteins EapH1 and EapH2 and autolysins Atl2 and Aly. No differences between epidemic and nonepidemic strains were found in the expression of virulence factors. Two days after inoculation, penetration of keratinocyte layers and the underlying filter occurred in 78% of samples. One day after inoculation, this was most frequent in epidemic isolates of CC8 (63%) and CC5 (50%) opposed to epidemic isolates of CC22 (17%) and CC30 (20%).

Conclusions:

This study shows the great ability of MRSA to form biofilms on human skin and penetrate the epidermis, irrespective of epidemiological success. Skin infection was associated with a specific profile of S. aureus virulence factors. Interestingly, penetration of the keratinocyte layers was more prominent in epidemic isolates of CC5 and CC8.

Keyword(s): Staphylococcus aureus, keratinocyte, skin infection

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