A sporadic four-year hospital outbreak of a ST97-IVa MRSA with half of the patients first identified in the community

TY - JOUR

T1 - A sporadic four-year hospital outbreak of a ST97-IVa MRSA with half of the patients first identified in the community

AU - Rubin, Ingrid M.

AU - Hansen, Thomas A.

AU - Klingenberg, Anne Mette

AU - Petersen, Andreas M.

AU - Worning, Peder

AU - Westh, Henrik

AU - Bartels, Mette D.

PY - 2018

Y1 - 2018

N2 - This study describes a sporadically occurring 4-year outbreak of methicillin-resistant Staphylococcus aureus (MRSA) originating from a surgical ward. Whole-genome sequencing (WGS) identified the outbreak clone as spa type t267, sequence type ST97, and SCCmec IVa. Prompted by the finding of four patients within 6 months in the same ward with this unusual MRSA type, an outbreak was suspected. Subsequent MRSA screening in the ward in February 2017 identified three-additional patients and two health care workers (HCWs) with t267/ST97-IVa. WGS linked these 9 isolates to 16 previous isolates in our WGS database and the outbreak thus included 23 patients and two HCWs. Twenty-one patients had a connection to the surgery ward during the period 2013-2017, but half of them had MRSA diagnosed in the community long after discharge. The community debut of several patients MRSA infections weeks to months after hospital discharge made the identification of a hospital source difficult and it was the SNP relatedness of the isolates that led us to identify the common denominator of hospitalization. An index patient was not identified, but our hypothesis is that HCWs with unrecognized long-term MRSA colonization could have caused sporadic nosocomial transmission due to intermittent breaches in infection prevention and control practice.

AB - This study describes a sporadically occurring 4-year outbreak of methicillin-resistant Staphylococcus aureus (MRSA) originating from a surgical ward. Whole-genome sequencing (WGS) identified the outbreak clone as spa type t267, sequence type ST97, and SCCmec IVa. Prompted by the finding of four patients within 6 months in the same ward with this unusual MRSA type, an outbreak was suspected. Subsequent MRSA screening in the ward in February 2017 identified three-additional patients and two health care workers (HCWs) with t267/ST97-IVa. WGS linked these 9 isolates to 16 previous isolates in our WGS database and the outbreak thus included 23 patients and two HCWs. Twenty-one patients had a connection to the surgery ward during the period 2013-2017, but half of them had MRSA diagnosed in the community long after discharge. The community debut of several patients MRSA infections weeks to months after hospital discharge made the identification of a hospital source difficult and it was the SNP relatedness of the isolates that led us to identify the common denominator of hospitalization. An index patient was not identified, but our hypothesis is that HCWs with unrecognized long-term MRSA colonization could have caused sporadic nosocomial transmission due to intermittent breaches in infection prevention and control practice.

KW - CO-MRSA

KW - HCWs

KW - Outbreak

KW - ST97

KW - WGS

U2 - 10.3389/fmicb.2018.01494

DO - 10.3389/fmicb.2018.01494

M3 - Journal article

C2 - 30042745

AN - SCOPUS:85049839132

SN - 1664-302X

VL - 9

SP - 1

EP - 6

JO - Frontiers in Microbiology

JF - Frontiers in Microbiology

M1 - 1494

ER -