Frequency-risk and duration-risk relations between occupational livestock contact and methicillin-resistant Staphylococcus aureus carriage among workers in Guangdong, China

• Published in: American journal of infection control Vol. 43; no. 7; pp. 676 - 681
• Main Authors: Ye, Xiaohua, PhD, Liu, Weidong, MSc, Fan, Yanping, MSc, Wang, Xiaolin, MSc, Zhou, Junli, MPH, Yao, Zhenjiang, PhD, Chen, Sidong, PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2015; Mosby-Year Book, Inc
• Subjects: Adolescent; Adult; Animals; Carrier State - epidemiology; Carrier State - microbiology; China; Community-acquired; Cross-Sectional Studies; Female; Genotype; Genotype & phenotype; Human; Humans; Infection Control; Infectious Disease; Interviews as Topic; Livestock; Male; Methicillin-resistant Staphylococcus aureus; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Middle Aged; Multilocus Sequence Typing; Nasal Mucosa - microbiology; Occupational Exposure; Regression analysis; Risk Assessment; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology; Staphylococcus infections; Young Adult; China; Guangdong China; Human; Community-acquired; Livestock; Methicillin-resistant Staphylococcus aureus
• ISSN: 0196-6553; 1527-3296
• DOI: 10.1016/j.ajic.2015.03.026

Background Increasing evidence indicates a strong association between occupational livestock contact and methicillin-resistant Staphylococcus aureus (MRSA) carriage. However, it remains unclear whether there are frequency-risk and duration-risk relations between occupational livestock contact and human MRSA carriage. Methods A cross-sectional survey was conducted in Guangdong, China, using a multistage sampling method. Participants were interviewed and provided a nasal swab for S aureus analysis. All MRSA isolates were genotyped by multilocus sequence typing. The dose-response relation was examined using logistic regression models. Results Among the 1,860 participants, 1.4% of controls tested positive for MRSA (characterized as sequence type [ST] 59 and ST7), and 7% of workers with livestock contact tested positive for MRSA (characterized as ST9, ST59, and ST7). There was a 5.31 times increased risk of MRSA carriage corresponding to occupational livestock contact (odds ratio = 6.31; 95% confidence interval, 3.44-11.57) using no contact as reference. We found frequency and short-term duration of occupational livestock contact were associated with increased risk of MRSA carriage in a dose-response manner. These significant trends were observed consistently among workers with occupational pig contact. However, no long-term duration-risk increasing trend was observed for occupational livestock or pig contact. Conclusion Our findings suggest that there may be dose-response relations between occupational livestock contact and human MRSA carriage. Nasal MRSA clonal complex 9 is not found in controls, but it is found in workers with livestock contact.