ANTIMICROBIALAGENTS ANDCHEMOTHERAPY, Apr. 2004, p. 1433–1434 Vol. 48, No. 4 0066-4804/04/$08.00⫹0 DOI: 10.1128/AAC.48.4.1433–1434.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.
Letters to the Editor
First Isolation of
bla
VIM-2
in Latin America: Report from the SENTRY
Antimicrobial Surveillance Program
Carbapenems, mainly imipenem and meropenem, are po-tent agents for the treatment of infections due to multiresistant
Pseudomonassp. clinical isolates. However, the prevalence of carbapenem resistance in this genus has been increasing world-wide. High-level resistance to carbapenems (⬎32g/ml) is still uncommon inPseudomonasspp. but can be due to the pres-ence of Ambler class B -lactamases—metallo--lactamases (MBLs) (1). Three different clinically relevant types of mobile MBLs have been described in the literature: IMP, VIM, and SPM (2, 4; H. Kurokawa, T. Yagi, N. Shibata, K. Shibayama, and Y. Arakawa, Letter, Lancet 354:955, 1999). The VIM family has been reported mostly in European and Asian coun-tries, although a distantly related MBL, VIM-7, has been char-acterized from the United States (5). We are not aware of VIM-type MBLs being reported from Latin America. In this work, we describe the presence ofblaVIM-2-producing
Pseudo-monas sp. isolates and characterize their genetic context among isolates obtained from Latin American medical centers representing Chile and Venezuela.
Four isolates of Pseudomonas spp., one of P. fluorescens
(43-14926) from a blood culture isolated in December 2002 in
Santiago, Chile, and three ofP.aeruginosa(49-4583, 49-4596, and 49-4597) recovered from respiratory tract samples be-tween August and September 2002 from the same hospital in Caracas, Venezuela, were obtained as part of the SENTRY Antimicrobial Surveillance Program. According to results of MIC tests performed as described by the National Committee for Clinical Laboratory Standards, the isolates were resistant to all-lactams, aminoglycosides, quinolones, and other antimi-crobial agents tested (Table 1). Only polymyxin B was active against all the isolates. MBL phenotypic tests were positive as judged by the disk approximation method (imipenem, mero-penem, ceftazidime, EDTA, and 2-mercaptopropionic acid) and the Etest MBL strips (AB Biodisk, Solna, Sweden) (7). These results were confirmed by spectrophotometric assays measuring imipenem hydrolysis, as previously described (4). Imipenem hydrolysis was inhibited by 88 to 97% for each of the strains by EDTA (20 mM) (Table 2).
Amplification with primers for the internal region ofblaVIM
-like genes and 5⬘ conserved sequence and 3⬘ conserved se-quence from class 1 integron and subsequent sequencing were performed as described earlier (3, 5). Primers used for ampli-fication and sequencing of theblaVIMgene were VIM-F
(5⬘-AAAGTTATGCCGCACTCACC-3⬘) and VIM-R (5⬘-TGCA ACTTCATGTTATGCCG-3⬘).
Sequencing results of the PCR amplicons revealed the pres-ence of the blaVIM-2 gene in the first position of a class 1
integron, which hasqacE⌬/su1ldownstream of the MBL gene. This integron gene arrangement has been previously reported for aP.aeruginosaisolate from a patient in France in 1996 (3). Other cases have been reported fromP.aeruginosain Greece in 2000 and fromSerratia marcescensin Korea in 2002 (6, 8). Class 1 integrons carryingblaVIM-type genes are now reported
to contain genes encoding aminoglycoside-modifying enzymes, and it is uncertain whether the arrangement of the integron without the additional genes is the progenitor.
Despite repeated attempts, plasmid DNA analysis of the isolates did not show any plasmids, and transformation exper-iments were unsuccessful. Experexper-iments in conjugation between the clinical isolates andEscherichia coliK-12 Rifr
did not yield any transconjugants. These data imply that theblaVIM-2found
in these isolates is likely to be chromosomally carried. Auto-TABLE 1. Antimicrobial susceptibility profiles of theblaVIM-2
-carryingPseudomonassp. isolates
Antimicrobial agent
MIC (g/ml)
P. fluorescens
43-14926
P. aeruginosa
49-4583 49-4596 49-4597
-Lactams
Cefazolin ⬎16 ⬎16 ⬎16 ⬎16
Cefoxitin ⬎32 ⬎32 ⬎32 ⬎32
Aztreonam ⬎16 ⬎16 16 16
Cefuroxime ⬎16 ⬎16 ⬎16 ⬎16
Ceftriaxone ⬎32 ⬎32 ⬎32 ⬎32
Ceftazidime ⬎16 ⬎16 ⬎16 ⬎16
Cefepime 16 ⬎16 ⬎16 ⬎16
Imipenem ⬎8 ⬎8 ⬎8 ⬎8
Meropenem ⬎8 ⬎8 ⬎8 ⬎8
Piperacillin-tazobactam ⬎64 64 64 64 Quinolones
Ciprofloxacin ⬎4 ⬎4 ⬎4 ⬎4
Gatifloxacin ⬎4 ⬎4 ⬎4 ⬎4
Levofloxacin ⬎4 ⬎4 ⬎4 ⬎4
Aminoglycosides
Amikacin 8 ⬎32 ⬎32 ⬎32
Gentamicin ⬎8 ⬎8 ⬎8 ⬎8
Netilmicin ⬎32 ⬎32 ⬎32 ⬎32
Tobramycin ⬎16 ⬎16 ⬎16 ⬎16
Others
Polymyxin B ⱕ1 ⱕ1 ⱕ1 ⱕ1
Tetracycline ⬎8 ⬎8 ⬎8 ⬎8
Trimethoprim-sulfamethoxazole
⬎2 ⬎2 ⬎2 ⬎2
TABLE 2. MICs by Etest MBL strips and imipenem hydrolytic activities (with and without EDTA) of theblaVIM-2-carrying
Pseudomonassp. isolates
Strain
Etest MBL MIC (g/ ml)
Hydrolytic activity
(absorbance/min) % Inhibition Imipenem Imipenem⫹EDTA Imipenem Imipenem⫹EDTA
43-14926 ⬎256 ⱕ1 0.07194 0.00384 94.6
49-4583 ⬎256 4 0.04519 0.00251 94.5
49-4596 ⬎256 6 0.10144 0.00253 97.5
49-4597 ⬎256 8 0.04359 0.00500 88.5
mated ribotyping and pulsed-field gel electrophoresis showed that the three isolates from Venezuela are identical, suggesting clonal spread. The strain from Chile was unique and belonged to a different species from those of the other MBL-producing strains.
Dissemination of multiresistant bacteria coupled with the plasticity of class 1 integrons suggests that resistance to main-stay anti-Pseudomonastherapies, such as expanded-spectrum cephalosporins and carbapenems, will continue to increase. We urge greater local screening for MBL-producing strains with the disk approximation tests (8; Kurokawa et al., letter) and the Etest MBL strip (7).
REFERENCES
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3.Poirel, L., T. Naas, D. Nicolas, L. Collet, S. Bellais, J. D. Cavallo, and P. Nordmann.2000. Characterization of VIM-2, a carbapenem-hydrolyzing me-tallo--lactamase, and its plasmid- and integron-borne gene from a Pseudo-monas aeruginosaclinical isolate in France. Antimicrob. Agents Chemother.
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evolutionarily distinct metallo--lactamase gene in aPseudomonas aeruginosa
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2000. Outbreak of infections caused byPseudomonas aeruginosaproducing VIM-carbapenemase in Greece. J. Clin. Microbiol.38:1290–1292.
7.Walsh, T. R., A. Bolmstro¨m, A. Qwa¨rnstro¨m, and A. Gales.2002. Evaluation of a new Etest for detecting metallo--lactamases in routine clinical testing. J. Clin. Microbiol.40:2755–2759.
8.Yum, J. H., D. Yong, K. Lee, H. S. Kim, and Y. Chong.2002. A new integron carrying VIM-2 metallo--lactamase gene cassette from aSerratia marcescens
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Rodrigo E. Mendes Mariana Castanheira
Disciplina de Doencas Infecciosas e Parasitarias Universidade Federal de Sao Paulo
Sao Paulo, Brazil
Patricia Garcia
Catholic University Hospital Macul Santiago, Chile
Manuel Guzman
Centro Medico de Caracas San Bernardio, Venezuela
Mark A. Toleman Timothy R. Walsh*
Department of Pathology and Microbiology University of Bristol
Bristol BS8 1TD, United Kingdom
Ronald N. Jones
The Jones Group JMI Laboratories North Liberty, Iowa
*Phone: 44 117 9288819 Fax: 44 117 9287896
E-mail: [email protected]
