Class 1 integron element in Thai Acinetobacter baumannii reveals a linkage to the European clone I

Abstract

BACKGROUND: Class 1 integron element is innate to most of the multidrug resistant Acinetobacter baumannii and its spread is common among international clones worldwide. The aim of this study was to document the presence of blaVEB-1 harboring class 1 integron element and its gene cassettes in Thai A. baumannii in relation to A. baumannii European clone I, AYE strain. MATERIALS AND METHODS: Thirty seven carbapenem resistant A. baumannii isolates identified in routine microbiology laboratory of Siriraj Hospital, Bangkok were studied. The dot blot hybridization was performed to detect class 1 integron element integrase gene. PCR was used to amplify blaVEB-1, arr2, cmlA, blaOXA-10 resistance cassettes, and variable region of class 1 integron element. blaVEB-1 gene was localized by southern blot hybridization. RESULTS: The prevalence of class 1 integron element was 86.48% in the isolates studied. The blaVEB-1 was present in 7 isolates however the location of blaVEB-1 gene was different in different isolate. Four isolates (Ab03-168, Ab04-28, Ab08-20, and Ab08-22) harbored calss 1 integron element variable region sized 5.5 kb as described in strain AYE. However, blaVEB-1 was only amplified from Ab03-168. The cassette organization in this isolate was 5’CS-aadB-blaVEB-1-arr2-cmlA-blaOXA- 10-aadA1-3’CS. The class 1 integron element similar to the element identified in genomic resistance island, AbaRI of European clone I, AYE was identified in Thai A. baumannii. CONCLUSIONS: blaVEB-1 harboring class 1 integron element with minor cassette variation was identified in Thai A. baumanni isolate which might suggest the spread of this resistant cassette or the spread of the European clone I in Thailand. Monitoring of the global spread of multi-resistant A. baumannii is mandatory to control the spread of resistant genes and this multi-resistant pathogen. DOI: http://dx.doi.org/10.3126/ijim.v1i1.6715Int J Infect Microbiol 2012;1(1):24-28

Genetic mechanisms and correlated risk factors of antimicrobial-resistant ESKAPEE pathogens isolated in a tertiary hospital in Malaysia

“…The bla VEB -carrying A. baumannii has been mainly reported in Europe and the Middle East causing nationwide outbreaks and HA infections [ 36 – 38 ]. In the Southeast Asian region, a study on class I integron revealed that the bla VEB -carrying A. baumannii in Thailand is genetically linked to the European clones [ 39 ]. Therefore, the emergence of bla VEB -carrying CRAB strains in Malaysia could be a result of foreign clonal invasion or the exchange of genetic elements between local and global strains.…”

Prevalence of extended-spectrum beta-lactamase genes in Acinetobacter baumannii strains isolated from nosocomial infections in Tehran, Iran

“…In the study carried out by Pasterán et al (2006) that investigated 21 ESBL-producing A. baumannii strains, the bla VEB gene was presented in 10 (47.6%) isolates [ 13 ]. In a study conducted by Thapa et al, out of 37 A. baumannii clinical isolates, the bla VEB was detected in 7 (9%) strains [ 14 ]. The disparate results between the current study and other research regarding the prevalence of the bla VEB gene may be due to the small sample size in the present study and/or different geographical locations.…”

“…The bla VEB-1 ESBL gene is belonging to class A β-lactamase and is located in a class 1 integron. These genetic structures are responsible for the expression of cassette-associated and mobile resistance genes, initially detected in Enterobacteriaceae and Pseudomonas aeruginosa from Southeast Asia [ 14 ], [ 15 ]. Subsequently, it has been described in clonally related A. baumannii isolates recovered during an outbreak that lasted 9 months (August 2001–April 2002) in the intensive care unit of a hospital in northern France.…”

Mechanism of resistance to beta-lactam antibiotics

“…The arr-2 gene cassette appears to be a major influencer of rifampicin resistance, a high MIC value for rifampicin and a decreased inhibition zone with disc diffusion was detected in arr-2 positive isolates, while the opposite was observed in arr-2 negative isolates (<14 mm) (56).…”