An outbreak of severe infections with community-acquired MRSA carrying the Panton-Valentine leukocidin following vaccination.
BACKGROUND
Infections with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are emerging worldwide. We investigated an outbreak of severe CA-MRSA infections in children following out-patient vaccination.


RESULTS
We carried out a field investigation after adverse events following immunization (AEFI) were reported. We reviewed the clinical data from all cases. S. aureus recovered from skin infections and from nasal and throat swabs were analyzed by pulse-field gel electrophoresis, multi locus sequence typing, PCR and microarray. In May 2006, nine children presented with AEFI, ranging from fatal toxic shock syndrome, necrotizing soft tissue infection, purulent abscesses, to fever with rash. All had received a vaccination injection in different health centres in one District of Ho Chi Minh City. Eight children had been vaccinated by the same health care worker (HCW). Deficiencies in vaccine quality, storage practices, or preparation and delivery were not found. Infection control practices were insufficient. CA-MRSA was cultured in four children and from nasal and throat swabs from the HCW. Strains from children and HCW were indistinguishable. All carried the Panton-Valentine leukocidine (PVL), the staphylococcal enterotoxin B gene, the gene complex for staphylococcal-cassette-chromosome mec type V, and were sequence type 59. Strain HCM3A is epidemiologically unrelated to a strain of ST59 prevalent in the USA, although they belong to the same lineage.


CONCLUSIONS
We describe an outbreak of infections with CA-MRSA in children, transmitted by an asymptomatic colonized HCW during immunization injection. Consistent adherence to injection practice guidelines is needed to prevent CA-MRSA transmission in both in- and outpatient settings.
Tang
Chi Thuong
CT
Pediatric Hospital No. 1, Ho Chi Minh City, Viet Nam.
Nguyen
Dac Tho
DT
Ngo
Thi Hoa
TH
Nguyen
Thi Minh Phuong
TM
Le
Van Tuan
VT
To
Song Diep
SD
Lindsay
Jodi
J
Nguyen
The Dung
TD
Bach
Van Cam
VC
Le
Quoc Thinh
QT
Le
Thanh Hai
TH
Le
Dieu Linh
DL
Campbell
James
J
Nguyen
Thi Kim Tien
TK
Nguyen
Van Vinh Chau
VV
Cockfield
Joshua
J
Le
Truong Giang
TG
Phan
Van Nghiem
VN
Le
Hoang Son
HS
Huynh
Tan Son
TS
Le
Van Phung
VP
Counahan
Megan
M
Bentsi-Enchill
Adwoa
A
Brown
Richard
R
Simmerman
James
J
Nguyen
Tran Chinh
TC
Tran
Tinh Hien
TH
Farrar
Jeremy
J
Schultsz
Constance
C
D000293:Adolescent; D001427:Bacterial Toxins / Q000378:metabolism*; D001428:Bacterial Vaccines / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005098:Exotoxins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007956:Leukocidins / Q000378:metabolism*; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D014744:Vietnam / Q000453:epidemiology