High-level cefotaxime-resistant Proteus mirabilis strain isolated from a Tunisian intensive care unit ward: CTX-M-8 extended-spectrum β-lactamase coproduced with a plasmid mediated AmpC lactamase

  • S Mahrouki
  • H Chihi
  • A Bourouis
  • K Ayari
  • M Ben Moussa
  • O Belhadj

Abstract

The aimed of this study was to determine the implication of the biochemical and the molecular mechanism and to describe the properties of an extended-spectrum β-lactamase (ESBL) CTX-M-8 which was reported for the first time in Africa. A clinical isolate of Proteus mirabilis FS6449 was isolated from a patient hospitalized at an intensive care unit of the Military Hospital in Tunisia in 2009. Antimicrobial susceptibility was determined with the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines and revealed that this strain was resistant to expanded-spectrum β-lactams. Analysis of P. mirabilis FS6449 by double-disk synergy test yielded a positive result suggesting the production of ESBLs. Sonicate of the isolate hydrolysed cefotaxime and benzylpenicillin. Isoelectric focusing exhibited four β-lactamase bands of isoelectric points (pIs) 5.6, 6, 6.5 and over 7.6. Polymerase chain reaction (PCR) and sequencing experiments revealed the presence of four β-lactamase genes encoding TEM-2, CTX-M-8, TEM-24, and an AmpC enzyme. Among them, the genes encoding TEM-24 and an AmpC enzyme were transferred to the recipient by conjugation experiments.

Keywords: Resistance, β-lactamase, Proteus mirabilis

African Journal of Biotechnology Vol. 12(21), pp. 3278-3282

Author Biographies

S Mahrouki
Laboratoire de Biochimie et Technobiologie, Faculté des Sciences de Tunis, Campus Universitaire, 2092 El-Manar II, Tunisie
H Chihi
Laboratoire de Biochimie et Technobiologie, Faculté des Sciences de Tunis, Campus Universitaire, 2092 El-Manar II, Tunisie
A Bourouis
Laboratoire de Biochimie et Technobiologie, Faculté des Sciences de Tunis, Campus Universitaire, 2092 El-Manar II, Tunisie
K Ayari
Laboratoire de Biochimie et Technobiologie, Faculté des Sciences de Tunis, Campus Universitaire, 2092 El-Manar II, Tunisie
M Ben Moussa
Service de Bactériologie, Hôpital Militaire de Tunis, 1089 Monfleury, Tunisie
O Belhadj
Laboratoire de Biochimie et Technobiologie, Faculté des Sciences de Tunis, Campus Universitaire, 2092 El-Manar II, Tunisie
Published
2016-03-14
Section
Articles

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eISSN: 1684-5315