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Year : 2014  |  Volume : 32  |  Issue : 3  |  Page : 352--353

First detection of a metallo-β-lactamase producing Serratia marcescens in a European university hospital

I Neonakis, H Messaritakis, D Stafylaki, S Maraki 
 Department of Bacteriology Parasitology Zoonoses and Geographical Medicine, Heraklion, Crete, Greece

Correspondence Address:
S Maraki
Department of Bacteriology Parasitology Zoonoses and Geographical Medicine, Heraklion, Crete

How to cite this article:
Neonakis I, Messaritakis H, Stafylaki D, Maraki S. First detection of a metallo-β-lactamase producing Serratia marcescens in a European university hospital.Indian J Med Microbiol 2014;32:352-353

How to cite this URL:
Neonakis I, Messaritakis H, Stafylaki D, Maraki S. First detection of a metallo-β-lactamase producing Serratia marcescens in a European university hospital. Indian J Med Microbiol [serial online] 2014 [cited 2020 May 30 ];32:352-353
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Dear Editor,

Serratia marcescens produces an AmpC-®-lactamase conferring resistance to many ®-lactams and also a chromosomal AAC (6′)-Ic enzyme that affects the activity of all major aminoglycosides except gentamicin. Moreover, all S. marcescens isolates are resistant to colistin. Hence, acquisition of any additional major resistance mechanism will render Serratia to one of the most problematic microorganisms. Metallo-®-lactamases (MBLs) can hydrolyse all ®-lactams except aztreonam. Although MBL-producing S. marcescens has sporadically been detected in different parts of the world, [1],[2],[3] to our knowledge this is the first report of its detection in a European hospital.

A 62-year-old patient presented at the emergency department of our institution with acute peritonitis. He underwent emergency surgery and he was transferred to the ICU. Two months later (January 2013) and over a 10-day-period S. marcescens (SM1113) was isolated from four different clinical samples of the 62-year-old patient (peritoneal fluid, catheter and two bronchoalveolar lavage samples).

Identification and susceptibility testing was performed with Vitek-2 (BioMérieux, France) and MICs to certain antimicrobials were determined with E-test (BioMérieux). All four isolates were resistant to the majority of antimicrobials with the exception of (MICs in parentheses): Aztreonam (<1 μg/ml), gentamicin (3 μg/ml), moxifloxacin (2 μg/ml), trimethoprim-sulfonamides (≤20 μg/ml) and tigecycline (4 μg/ml; intermediate). It was resistant to imipenem (>32 μg/ml), and intermediately resistant to meropenem (6 μg/ml). Detection for Extented-Spectrum-®-lactamases or AmpC hyperproduction with the relevant E-test strips was negative. Modified Hodge Test was positive verifying the presence of a carbapenamase. The applied meropenem (10 μg)-EDTA and meropenem-3-aminophenylboronic acid (300 μg) synergy tests ruled out the presence of a KPC-type carbapenamase and clenched the production of an MBL. Regimens including moxifloxacin and tigecycline were administered with favourable outcome.

Our region was one of the first worldwide to detect production of an MBL by Enterobacteriaceae. [4] Now, a difficult-to-handle Enterobacteriaceae such as S. marcescens has acquired an additional major resistance mechanism. As shown in a recent 5-year study conducted in our setting 65 infections were attributed to S. marcescens, with the majority of them being respiratory tract infections. [5] Among these 65 patients, three (4.6%) eventually died due to the Serratia infection. It is anticipated that a possible spread and prevalence of the MBL-producing S. marcescens will dramatically increase the number of infections and deaths in our institution.


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2Nastro M, Monge R, Zintgraff J, Vaulet LG, Boutureira M, Famiglietti A, et al. First nosocomial outbreak of VIM-16-producing Serratia marcescens in Argentina. Clin Microbiol Infect 2013;19:617-9.
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4Scoulica EV, Neonakis IK, Gikas AI, Tselentis YJ. Spread of bla (VIM-1)-producing E. coli in a university hospital in Greece. Genetic analysis of the integron carrying the bla (VIM-1) metallo-beta-lactamase gene. Diagn Microbiol Infect Dis 2004;48:167-72.
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