Secular trends and dynamics of hospital associated methicillin-resistant Staphylococcus aureus

• Published in: Clinical microbiology and infection Vol. 16; no. 9; pp. 1435 - 1441
• Main Authors: Armand-Lefevre, L., Buke, C., Ruppe, E., Barbier, F., Lolom, I., Andremont, A., Ruimy, R., Lucet, J.-C.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01.09.2010; Blackwell Publishing Ltd; Wiley-Blackwell; Elsevier Limited
• Subjects: Adult; Age; Aged; Aged, 80 and over; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Bacterial diseases; Bacterial Typing Techniques; Biological and medical sciences; Clinical isolates; cross infection; Cross Infection - epidemiology; Cross Infection - microbiology; Drug resistance; epidemiology; Female; France; Genotype; Gentamicin; Hospitals; Human bacterial diseases; Humans; Incidence; Infectious diseases; Intensive care units; Male; Medical research; Medical sciences; methicillin resistance; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Microbial Sensitivity Tests; Middle Aged; Molecular Epidemiology; Multilocus Sequence Typing; Obstetrics; Paris - epidemiology; Pharmacology. Drug treatments; Retrospective Studies; risk factors; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology; Staphylococcal infections, streptococcal infections, pneumococcal infections; Staphylococcus aureus; Staphylococcus infections; Tobramycin; Typing; France; Europe; Paris; epidemiology; methicillin resistance; risk factors; France; cross infection; Staphylococcus aureus; β-Lactams; Epidemiology; Meticillin; Penicillin derivatives; Infection; Resistance; Antibiotic; Risk factor; Bacteriosis; Bacteria; Micrococcales; Micrococcaceae; Hospital; Antibacterial agent; Staphylococcal infection
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1111/j.1469-0691.2010.03138.x

We performed an 11-year retrospective analysis of consecutive nonduplicate methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates in two neighbouring hospitals in the Paris area. MRSA isolates were classified according to resistance (R) to fluoroquinolones (Fq), kanamycin (K), tobramycin (T) and gentamicin (G). The yearly number of MRSA isolates (3446 in total) decreased, from approximately 350 in 1997–2002 to 212 in 2007. Four patterns (P) were found: P1 (KTGFq R, n = 776), P2 [KTFq R; G susceptible (S), n = 1630], P3 (Fq R; KTG S, n = 397) and P4 (Fq S; any KTG susceptibility, n = 201). P1 predominated in 1997 (183 isolates) then dropped sharply (nine in 2007); P2 and P4 remained stable over time; and P3 increased from 13 isolates in 1997 to 72 in 2007. Patterns were significantly and positively associated with several variables, independently of the year of collection: P1, age < 80 years, male gender, intensive care unit stay, and hospital onset; P3, age > 80 years and stay in intermediate or long-term care wards; and P4, age < 40 years, stay in an obstetric ward, and imported cases. Molecular typing of 79 isolates in 2005 and 2007 using multilocus sequence typing, spa type, and SCCmec showed that P1, P2 and P3 isolates were mainly clonal, whereas P4 isolates were more diverse. P1 comprised mainly ST247-1 isolates, P2 mainly ST8-IVc, and P3 mainly ST8-IVc and ST5-VI. In conclusion, the epidemiology of MRSA in Paris is changing rapidly at the local level, with phenotypically defined clones being substituted by others, with associations existing between changes in specific patient populations or circumstances.