Studying the transmission dynamics of meticillin-resistant Staphylococcus aureus in Hong Kong using spa typing

• Published in: The Journal of hospital infection Vol. 79; no. 3; pp. 206 - 210
• Main Authors: Cheng, V.C.C, Chan, J.F.W, Lau, E.H.Y, Yam, W.C, Ho, S.K.Y, Yau, M.C.Y, Tse, E.Y.F, Wong, A.C.Y, Tai, J.W.M, Fan, S.T, Ho, P.L, Yuen, K.Y
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2011; Elsevier
• Subjects: Adult; Aged; Aged, 80 and over; Bacterial diseases; Bacterial Typing Techniques; Biological and medical sciences; Carrier State - microbiology; Carrier State - transmission; Cross Infection - microbiology; Cross Infection - prevention & control; Cross Infection - transmission; Female; General aspects; Hong Kong; Hospital Units; Hospitals, University; Human bacterial diseases; Human infectious diseases. Experimental studies and models; Humans; Incidence; Infection Control; Infectious Disease; Infectious diseases; Male; Medical sciences; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Meticillin-resistant Staphylococcus aureus; Middle Aged; Nose - microbiology; Nosocomial transmission; Spa type; Staphylococcal Infections - microbiology; Staphylococcal Infections - prevention & control; Staphylococcal Infections - transmission; Staphylococcal infections, streptococcal infections, pneumococcal infections; Staphylococcal Protein A - classification; Staphylococcal Protein A - genetics; Staphylococcus aureus; Surgery Department, Hospital; Transmissibility; Transmission dynamics; Hong Kong; Asia; China; Nosocomial transmission; Transmissibility; Spa type; Meticillin-resistant Staphylococcus aureus; Transmission dynamics; Nosocomial infection; Typing; Transmission; Infection; Microbiological investigation; Bacteriosis; Bacteria; Micrococcales; Micrococcaceae; Staphylococcal infection; Public health; Staphylococcus aureus
• ISSN: 0195-6701; 1532-2939
• DOI: 10.1016/j.jhin.2011.03.024

Summary This study investigated the transmission dynamics of meticillin-resistant Staphylococcus aureus (MRSA) in a tertiary referral surgical unit with 300 beds. All adult patients were actively screened for MRSA by culture at hospital admission and twice weekly thereafter during hospitalisation from 1 October to 31 December 2008. The colonisation pressure per 1000 patient-days and the incidence density of nosocomial MRSA transmission per 1000 colonisation-days were calculated for the different spa types of MRSA. In total, 6619 nasal swabs were obtained from 2289 patients. One-hundred and forty-eight (7%) patients had MRSA in nasal swabs at admission screening, of which 68/148 (46%) were residents of elderly care homes. Fifty-two of 2141 (2%) patients had conversion of nasal MRSA carriage status from negative to positive during hospitalisation. Among the 200 patients with MRSA, spa types t1081 and t037 were found in 99 (50%) and 30 (15%) patients, respectively. The colonisation pressure per 1000 patient-days was 40.9 for t0181, 22.2 for t037 and 26.3 for the less common spa types. The incidence densities of nosocomial MRSA transmission per 1000 colonisation-days were significantly higher for t1081 (28.5 vs 4.0, P < 0.01) and t037 (21.5 vs 4.0, P = 0.03) compared with the less common spa types. Proactive screening of MRSA in patients from elderly care homes and targeted isolation of these patients, especially those carrying spa types with high transmissibility, are important for the control of MRSA in hospitals.