Impacts of a long-term programme of active surveillance and chlorhexidine baths on the clinical and molecular epidemiology of meticillin-resistant Staphylococcus aureus (MRSA) in an Intensive Care Unit in Scotland

• Published in: International journal of antimicrobial agents Vol. 40; no. 4; pp. 323 - 331
• Main Authors: Sangal, Vartul, Girvan, E. Kirsty, Jadhav, Sagar, Lawes, Timothy, Robb, Andrew, Vali, Leila, Edwards, Giles F, Yu, Jun, Gould, Ian M
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2012; Elsevier
• Subjects: Active surveillance; Anti-Infective Agents, Local - administration & dosage; antibiotic resistance; antibiotics; Antibiotics. Antiinfectious agents. Antiparasitic agents; Bacterial diseases; Bacterial Typing Techniques; Baths - methods; Biological and medical sciences; chlorhexidine; Chlorhexidine - administration & dosage; Chlorhexidine baths; clones; compliance; Cross Infection - drug therapy; Cross Infection - epidemiology; Cross Infection - microbiology; Cross Infection - prevention & control; disease control; Epidemiological Monitoring; glycopeptides; Human bacterial diseases; Humans; ICU; Infection Control - methods; Infectious Disease; Infectious diseases; Intensive Care Units; Medical sciences; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Molecular Epidemiology; Molecular Typing; monitoring; MRSA; multilocus sequence typing; Pharmacology. Drug treatments; pulsed-field gel electrophoresis; Scotland - epidemiology; screening; Staphylococcal Infections - drug therapy; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology; Staphylococcal Infections - prevention & control; Staphylococcal infections, streptococcal infections, pneumococcal infections; Staphylococcus aureus; Scotland; United Kingdom; Great Britain; Europe; Chlorhexidine baths; ICU; Active surveillance; MRSA; Genotype; Guanidines; Bath; Long term; Intensive care unit; Infection; Biguanides; Surveillance; Antiseptic; Bacteriosis; Molecular epidemiology; Bacteria; Micrococcales; Micrococcaceae; Chlorhexidine; Disinfecting agent; Staphylococcal infection; Staphylococcus aureus
• ISSN: 0924-8579; 1872-7913
• DOI: 10.1016/j.ijantimicag.2012.06.007

Evidence is accumulating that active surveillance, when combined with appropriate infection control, is a successful measure for controlling hospital-acquired meticillin-resistant Staphylococcus aureus (MRSA). In this study, the impacts of a long-term control strategy of this type, including the use of chlorhexidine baths, on the clinical and molecular epidemiology of MRSA in the Intensive Care Unit of Aberdeen Royal Infirmary were investigated. Characterisation of 85 sequential index MRSA isolates was performed using phenotypic methods (biotyping), antibiotic susceptibility testing and three genotypic methods (pulsed-field gel electrophoresis, spa typing and multilocus sequence typing) over a 4-year period. There was no evidence of loss in effectiveness of the control strategy over the study period. Compliance with screening remained high (>85%) throughout and there was no significant increase in the prevalence of MRSA detected in surveillance (P=0.43 for trend) or clinical cultures (P=0.79). There were no significant trends in rates of other index surveillance organisms (P>0.5). Results of the three typing methods were in general agreement with three prevalent MRSA clones [clonal complex 22 (CC22), CC30 and CC45]. CC22 emerged as the dominant clonal complex alongside a significant decline in CC30 (P=0.002). CC45 was significantly more likely to be positive in glycopeptide resistance screens (P<0.001). There was no increase in antibiotic or chlorhexidine resistance. Long-term chlorhexidine bathing was not associated with any detectable loss of efficacy or increase in resistance in MRSA or with any increase in infection with other organisms. Changing clonal epidemiology occurred with no overall change in the prevalence of MRSA.