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Molecular epidemiology of methicillin-resistant and methicillin-sensitive Staphylococcus aureus invasive isolates in Russia

Abstract number: P1064

Dmitrenko O., Lavrova N., Alexandrova I., Ghilina S., Karabak V., Rosanova S., Gintsburg A.

Objectives: During investigation conducted in 2002–2006 we discovered circulation of several epidemic MRSA strains in hospitals in Russia. Two of them REMRSA-1(spa-037, SCCmec type III) and REMRSA-2 (spa-008, composite SCCmec: comlex mecB+, ccr1+, ccr2+) were discovered in different parts of the country and REMRSA-3 (spa-030, SCCmecIII) was identified only in one hospital of the Central Region. In the last few years the MRSA proportion increased dramatically especially among ICU patients. The increase incidents of invasive staphylococcal infections were observed two. The aim of the present study was to identify the MRSA genotypes currently circulating in the healthcare settings and to compare genotype and superantigen profiles of invasive MRSA and MSSA isolates.

Methods: 115 Staphylococcus aureus isolates were collected in 2005–2009 in 9 hospitals of Central, Ural and North-West region of Russia from blood (50), spinal fluid (4), low respiratory tract (61). Antimicrobial susceptibility was determined by standard methods. Genetic background was investigated by coa and spa typing. Structural components of SSCmec, sea, seb, sec, seh, seg, tst, pvl were tested by PCR additionally.

Results: 74 (64.3%) isolates were methicillin-resistant (MRSA). Among 30 MRSA recovered from blood and spinal fluid 14 (46.6%) were REMRSA-2 and 16 (53.4%) were REMRSA-3. Among 44 low respiratory tract isolates 42 (95.4%) were REMRSA-3, and 2 (4.6%) were REMRSA-2. REMRSA-3 was detected in 8 of the 9 participating hospitals. MRSA isolates recovered in different hospitals differed by toxin genes profiles. 96.6% isolates carried sea. One isolate of REMRSA-2 (6.3%) was sea+pvl+. Among REMRSA-3 17.2% isolates carried sea,sec; 10.3% isolates carried sea,sec,tst. Isolates of REMRSA-1 were not discovered. In methicillin-sensitive S. aureus (MSSA) isolates recovered from blood (24) and respiratory tract (9) spa-types 002, 015, 078, 156, 159, 164, 284, 359, 647, 737, 841, 3665 were discovered. 16.6% of MSSA isolates carried tst or pvl.

Conclusion: Progressive increase of the proportion of the MRSA isolates in hospitals in Russia is a result of dissemination REMRSA-3 (spa-type t030, SCCmec III). This strain was able to accumulate the toxin genes successfully and replaced REMRSA-1 (spa t037, SCCmecIII). It became the predominant strain as a causative agent of staphylococcal ventilator-associated pneumonia. MSSA invasive isolates differed from MRSA by genetic background and toxin genes profiles.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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