Molecular epidemiology of methicillin-resistant Staphylococcus aureus isolates from clinical specimens of patients with nosocomial infection: are there unnoticed silent outbreaks?
Bacteriological and epidemiological studies were carried out on 90 isolates of methicillin-resistant Staphylococcus aureus (MRSA) at Turgut Ozal Medical Center of Inönü University, (Malatya/Turkey). MRSA isolates were obtained from patients with nosocomial infections. Staphylococcus aureus clinical isolates were collected between May 2004-May 2005. Isolates were tested for resistance to methicillin. Antimicrobial susceptibility testing and slime production evaluation was performed. Genotype studies were carried out by arbitrarily primed polymerase chain reaction (AP-PCR) and consequent cluster analysis. All of the isolates were mecA-positive in a PCR-based assay; all exhibited resistance to oxacillin, by agar dilution (MICs > or = 4 mg/L) and disc diffusion methods, and multiple antibiotics. Most MRSA isolates were collected in intensive care units. Of 90 samples, 53 were found to be unrelated to the others while the remaining 37 strains were either identical or closely related. Dendrogram analysis identified nine major clusters. These data support the opinion that MRSA are significant nosocomial pathogens in intensive care units and that resistant clones may be transmitted between patients. Molecular epidemiological tools are helpful for understanding transmission patterns and sources of infection, and are useful for measuring outcomes of intervention strategies implemented to reduce nosocomial MRSA.
Tekerekoglu
Mehmet Sait
MS
Department of Medical Microbiology, Faculty of Medicine, Inonu University, Malatya, Turkey.
Ay
Selma
S
Otlu
Baris
B
Ciçek
Aysegul
A
Kayabaş
Uner
U
Durmaz
Riza
R
D000046:Academic Medical Centers; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial; D005838:Genotype; D006801:Humans; D007362:Intensive Care Units; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D046915:Penicillin-Binding Proteins; D016133:Polymerase Chain Reaction / Q000379:methods; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D014421:Turkey / Q000453:epidemiology
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; D011135:Polysaccharides, Bacterial; C487789:mecA protein, Staphylococcus aureus