|Year : 2015 | Volume
| Issue : 4 | Page : 601-602
Molecular characterization of plasmid-mediated blactx-M15 extended spectrum β lactamase (esbls) in Acinetobacter spp. Isolates from intensive care unit patients, at a tertiary care hospital, South India
E Kumar1, K Usha1, BV Ramana2, A Chaudhury2, DVR Sai Gopal1
1 Department of Virology, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
2 Department of Microbiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
|Date of Submission||05-Feb-2014|
|Date of Acceptance||12-Jan-2015|
|Date of Web Publication||16-Oct-2015|
DVR Sai Gopal
Department of Virology, Sri Venkateswara University, Tirupati, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kumar E, Usha K, Ramana B V, Chaudhury A, Gopal DS. Molecular characterization of plasmid-mediated blactx-M15 extended spectrum β lactamase (esbls) in Acinetobacter spp. Isolates from intensive care unit patients, at a tertiary care hospital, South India. Indian J Med Microbiol 2015;33:601-2
|How to cite this URL:|
Kumar E, Usha K, Ramana B V, Chaudhury A, Gopal DS. Molecular characterization of plasmid-mediated blactx-M15 extended spectrum β lactamase (esbls) in Acinetobacter spp. Isolates from intensive care unit patients, at a tertiary care hospital, South India. Indian J Med Microbiol [serial online] 2015 [cited 2019 Dec 12];33:601-2. Available from: http://www.ijmm.org/text.asp?2015/33/4/601/167348
Acinetobacter spp. is one of the established nosocomial bacteria. Extended spectrum β lactamases (ESBLs) hydrolyse third generation cephalosporins, aztreonam and inhibited by clavulanate.bla CTX-M type ESBLs are preferentially active against cefotaxime and are less active against ceftazidime. Eighty-four cefotaxime-resistant Acinetobacter spp. were isolated from intensive care unit (ICU) patients during May 2013–October 2013.
Out of 84 isolates, 45.23% (38) and 54.76% (46) were screened positive and negative, respectively, for ESBLs by Disc diffusion test (DDT). Polymerase chain reaction (PCR) was performed to amplify bla CTX-M alleles as previously described  and analysed in 1% agarose and documented [Figure 1]. Eighteen (21.42%) including 15 DDT-positive and 3 DDT-negative isolates were showed bla CTX-M gene. The phenotypic differentiation of bla CTX-M β-lactamase producers from other β-lactamase producers can be difficult due to overlapping with other or multiple β-lactamases. For better identification, molecular-based methods are needed to indent and monitoring the emergence of bla CTX-M. bla CTX-M15 has been documented worldwide and only few reports are available from India. In this study, PCR products were sequenced and homology was checked with Basic Local Alignment Search Tool (BLAST) available in National Center for Biotechnology Information (NCBI). The phylogenetic tree was constructed with available reference sequences KF971880, KC817477, GQ174506, GQ983249, GQ983244, GQ983243, GQ983232 and GQ983231 using MEGA 4 software [Figure 2]. The present study sequence (KJ127475) showed maximum 98.84% similarity matrix with sequences (KF971880 and KC817477 sequences belongs to Russian Country) at nucleotide level. Results of the phylogenetic analysis showed that the sequence obtained in this study was imported probably from Russian country. The other possibility could be that bla CTX-M was circulating in some other bacteria in the country. In clinical isolates, bla CTX-M type enzymes are considered as the most important unconventional ESBLs and are not closely related to sulfhydryl variable (SHV) or Temoneira enzymes (TEM), these genes have been commonly located on plasmids and carry the resistance genes to multiple drugs such as aminoglycosides, chloramphenicaol, sulfanamide, trimethoprim and tetracycline. The findings of the present study confirm the occurrence of bla CTX-M type ESBLs from our region among clinically relevant Acinetobacter spp. which leads serious hazard to clinical use of 3rd generation cephalosporins for treatment. In our study, 21.42% isolates were found to be bla CTX-M as part of ESBLs; remaining strains may be due to other bla genes. Our study prevalence is closely (22.5%) related to Leila Nasehi et al., study.
|Figure 1: Polymerase chain reaction amplification of CTX-M gene in cefotaxime resistant Acinetobacter spp M: 1kb deoxyribonucleic acid Marker; 1 and 2: Negative; 3 and 4: Positive; NC: Negative control|
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|Figure 2: Bootstrapped NJ (phylogenetic) tree representing the phylogenetic relationships of bla CTX-M genes in Acinetobacter spp. The present study sequence indicated with dark circle-Acinetobacter spp. SVU/SVIMS1 (KJ127475) shows grouping with Russian sequences of A.baumanii strain B-1394A (KF971880) and A. baumannii strain K-174 (KC817477)|
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We concluded from the present study that the findings of bla CTX-M gene in clinical isolates indicated the emerging problem in our region. For epidemiology purpose, similar studies to be needed to know genotypes of ESBL enzymes in different parts of the country.
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Conflicts of interest.
There are no conflicts of interest.
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