Acinetobacter baumannii extensively drug resistant lineages in Buenos Aires hospitals differ from the international clones I-III

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• 作者：Marí ; a Silvina Stietz^a ; Marí ; a Soledad Ramí ; rez^a ; Elisabet Vilacoba^a ; Adriana Karina Merkier^a ; Adriana Sara Limansky^b ; Daniela Centró ; n^a ; Mariana Catalano^a ; ^{catalano@fmed.uba.ar}
• 关键词：Acinetobacter baumannii ; Multilocus sequence typing ; PFGE
• 刊名：Infection, Genetics and Evolution
• 出版年：2013
• 出版时间：March, 2013
• 年：2013
• 卷：14
• 期：Complete
• 页码：294-301
• 全文大小：419 K

文摘

As a way to contribute to the assessment of Acinetobacter baumannii clinical population structure, multi-locus sequence typing (MLST) was performed in a collection of 93 isolates from Buenos Aires (1983-2012) and Rosario (2006-2009) hospitals. Sequence types (STs) were achieved by Bartual (B) and Institut Pasteur (P) schemes. PFGE typing, antimicrobial susceptibility assays, and the amplification of the OXA carbapenemase genes most prevalent in our region, were also performed.

e-Burst clustered the 25 STs^B (15 novels) into 5 clonal complexes (CC) and 5 singletons, and grouped the 18 STs^P (12 novels) into 3 CC and 4 singletons. Bartual scheme divided the CC79^P into two groups. CC113^B/CC79^P prevailed in Buenos Aires at least in 1992-2009, being responsible for epidemic and for endemic infections and acquiring the XDR (extensively drug-resistant) pattern throughout the years. While, CC119^B/CC79^P was apparently present before the CC113^B/CC79^Pdomain. CC103^B/CC15^P was the second most prevalent CC. Interestingly, CC110^B/ST25^P apparently increased over the last years. Conversely, CC109^B/CC1^P (international clone I) predominated in Rosario, although the presence of CC113^B/CC79^P, CC103^B/CC15^P and CC110^B/ST25^P was observed. Nineteen novel STs clustered in CC79^P, CC15^P, CC113^B, CC109^B and CC103^B, suggesting their clonal expansion during persistence. PFGE typing proved transmission of strains intra- and inter-hospitals in each city. Except for one, all the recent isolates (2007-2012) harboured the bla_OXA-23-like. All isolates were susceptible to colistin. Tigecycline MIC⁹⁰ was 1 mg/L and the rifampicin MIC > 512 mg/l was found among isolates in three hospitals.

In conclusion, the international clone II (CC92^B/CC2^P) was not found among our isolates. CC113^B/CC79^P_, CC103^B/CC15^P, and ST25^P, suggested also as major components in the A. baumannii population together with the international clone I, were present in Buenos Aires and Rosario with different prevalence rate. Their recent isolates showed high distribution of the bla_OXA-23-like as well as the XDR pattern.