Emergence and spread of carbapenem-resistant Acinetobacter baumannii in a tertiary care hospital in Turkey

Abstract

An intensive care unit (ICU)-based OXA-23-producing multiple-drug resistant Acinetobacter baumannii (MDRAB) outbreak was detected between October 2005 and October 2006. A total of 47 patients were infected/colonized with the outbreak strain. Clinical data were available from 37 patients. The all-cause mortality rate among the patients exposed to the epidemic strain was 35% (13/37). The outbreak strain and the resistance determinants were characterized both by microbiological methods and by molecular techniques. Cloning and sequencing experiments identified ISAbaI-associated bla(oxa-23) on the chromosome. Screening of imipenem-resistant Acinetobacter isolated from the ICU during the outbreak period with PCR identified 97 isolates as positive for the ISAbaI-bla(oxa-23) structure. Pulsed-field gel electrophoresis and plasmid analyses with selected nonrepetitive isolates revealed the clonality. Disk diffusion on cloxacillin-supplemented agar media and the real-time PCR experiments showed that outbreak isolates are overexpressing the ampC enzyme. This study highlights the occurrence of OXA-23-producing and ampC-overexpressing MDRAB in ICUs.

Carbapenem resistance in Acinetobacter baumannii: the molecular epidemic features of an emerging problem in health care facilities

“…Also, plasmids carrying resistance genes and/or resistance determinants involved in horizontal gene transfer have been described in several A. baumannii strains [12][13][14][15][16][17][18][19].…”

“…Three main acquired carbapenem-hydrolysing class D oxacillinase (CHDL) gene clusters have been identified either in the chromosome or in plasmids of A. baumannii strains, represented by the bla OXA-23 -, bla OXA-24/40 -, and bla OXA-58 -like genes [12]. Different insertion sequence (IS) elements at the 5' and/or the 3' end of bla OXA-23 -, and bla OXA-58 -like genes, such as ISAba1, ISAba2, ISAba3, or IS18, have been demonstrated to regulate their expression [12,13,[15][16][17]. Also, it has been recently demonstrated that the ISAba1 element is capable of transposition in E. coli and of mobilizing an antibiotic resistance gene [18].…”

“…Surveillance studies indicate that the percentage of carbapenemresistant isolates gradually increased over the last ten years in Europe, North America, and Latin America [2]. Numerous outbreaks of carbapenem-resistant A. baumannii were reported from hospitals in Northern Europe (Spain, Portugal, France, the United Kingdom (UK), the Netherlands, Czech Republic, Poland) [1,2,[24][25][26][27][28][29], Southern Europe and the Middle East (Bulgaria, Greece, Italy, Turkey, Lebanon, Israel, Iran, Iraq and United Arab Emirates) [2,[6][7][8]10,12,14,16,17,[30][31][32][33][34][35], North America and Latin America (Argentina, Brazil, Chile and Colombia) [2,36,37], Tunisia and South Africa [38,39], China, Taiwan, Singapore, Hong Kong, Japan, South Korea [2,40,41], and Australia [42] and from areas as remote as French Polynesia [43]. In the majority of cases, one or two epidemic strains were detected in a given hospital.…”

“…bla OXA-23 was mostly detected in isolates from Asian countries [41], but was also reported in South America [36,37] and Europe [12,17,31,51]; bla OXA-58 was frequently found in Europe [6,7,10,14,30,33,16,[30][31][32][33][34][35]51]. bla OXA-24/40 was mostly found in the Iberian peninsula and Asia, but also detected in Iran, Belgium, Czech Republic and the United States of America (USA) [2,26,27,41,44,51,52] ( Figure 1).…”

Antimicrobial Susceptibility Pattern and Prevalence of Extended-Spectrum β-Lactamase Genotypes among Clinical Isolates of Acinetobacter baumanii in Tabriz, North-West of Iran

“…This bacterium causes a variety of diseases including urinary tract infections, endocarditis, surgical site infections, pneumonia, septicemia, and meningitis (1,5). Numerous strains of A. baumannii have recently emerged to be resistant against a wide spectrum of antibiotics, particularly β-lactams, which have so far been among drug choices for treatment of A. baumannii infections.…”