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[Changes of methicillin-resistant Staphylococcus aureus (MRSA) phagotypes in Gdansk in 1990-1998]
K Wiśniewska1, L Piechowicz, J Galiński
1Katedra i Zakład Mikrobiologii Lekarskiej AM w Gdańsku.
Abstract:
The aim of the study was the assessment of changes in the occurrence of various MRSA phagotypes in hospitals in the Gdańsk area in 1990-1998. The study was carried out on 175 MRSA strains: 45 strains isolated in 1990-1995 and 130 in 1997-1998. The studied staphylococci were obtained from various clinical materials from patients in 18 hospitals. Phagotyping was done with a set of 10 experimental phages from MRSA strains obtained from the Central Public Health Laboratory in London. Drug-resistance was determined by the disc-diffusion method and in case of strains with medium susceptibility to fusidic acid the minimal inhibitory concentration (MIC) was determined by serial dilutions on solid medium. The study showed among MRSA strains isolated in 1997-1998 a new, previously not known strains with phage pattern MR25/M5 predominated (57.7%). Its presence was found in various hospitals in that area. MRSA belonging to MR25/M5 phagotype were mostly resistant to doxycycline, gentamycin, erythromycin, clindamycin, ciprofloxacin, rifampicin and were resistant or only had medium susceptibility to fusidic acid. The MIC values for strains with medium susceptibility to fusidic acid (4-8 micrograms/ml) showed an evident decrease of the susceptibility to this antibiotic, formerly common in MRSA. At the same time, in 1997-1998 a considerable decrease was observed of the number of MRSA strains belonging to MR8/MR12/MR25/30/33/38/M5/622 phagotype (from 31.1% to 0.8%), and disappearance of strains with phagotypes MR25/56B/M3 and MR8/MR25/622, which in 1990-1995 accounted for 15.6% of the studied staphylococci.
Insights
A new Methicillin-resistant Staphylococcus aureus (MRSA) phagotype, MR25/M5, emerged and predominated in Gdańsk hospitals between 1997-1998, showing multi-drug resistance. This new strain replaced previously common MRSA phagotypes, indicating a significant shift in circulating strains.
Area of Science:
- Microbiology
- Epidemiology
- Infectious Diseases
Context:
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat in hospital settings.
- Monitoring the evolution and prevalence of MRSA strains is crucial for effective infection control.
- Previous studies documented specific MRSA phagotypes in the Gdańsk region during the early 1990s.
Purpose:
- To assess the changes in occurrence of various MRSA phagotypes in Gdańsk area hospitals from 1990 to 1998.
- To characterize the drug resistance patterns of predominant MRSA strains.
- To identify emerging MRSA strains and track the decline of previously common ones.
Summary:
- The study analyzed 175 MRSA strains isolated between 1990-1998 from 18 hospitals in the Gdańsk area.
- A new MRSA phagotype, MR25/M5, emerged and predominated (57.7%) in 1997-1998, exhibiting resistance to multiple antibiotics including doxycycline, gentamycin, and erythromycin.
- Previously dominant phagotypes, such as MR8/MR12/MR25/30/33/38/M5/622, significantly decreased or disappeared, while MR25/M5 showed reduced susceptibility to fusidic acid.
Impact:
- Identified the emergence and dominance of a new, multi-drug resistant MRSA phagotype (MR25/M5) in a specific geographic region.
- Demonstrated a significant epidemiological shift in circulating MRSA strains over a decade.
- Highlighted the changing susceptibility patterns of MRSA to antibiotics like fusidic acid, necessitating updated treatment guidelines.