Tunisian Multicenter Study on the Prevalence of Colistin Resistance in Clinical Isolates of Gram Negative Bacilli: Emergence of <i>Escherichia coli</i> Harbouring the <i>mcr-1</i> Gene
Sana Ferjani,
Elaa Maamar,
Asma Ferjani,
Khaoula Meftah,
Hager Battikh,
Besma Mnif,
Manel Hamdoun,
Yosra Chebbi,
Lamia Kanzari,
Wafa Achour,
Olfa Bahri,
Adenene Hammami,
Meriam Zribi,
Hanen Smaoui,
Ilhem Boutiba-Ben Boubaker
Affiliations
Sana Ferjani
Faculty of Medicine of Tunis, University of Tunis El Manar, LR99ES09, Tunis Rue Djebal Lakhdar 1006, Tunisia
Elaa Maamar
Faculty of Medicine of Tunis, University of Tunis El Manar, LR99ES09, Tunis Rue Djebal Lakhdar 1006, Tunisia
Asma Ferjani
Faculty of Medicine of Tunis, University of Tunis El Manar, LR99ES09, Tunis Rue Djebal Lakhdar 1006, Tunisia
Khaoula Meftah
Laboratory of Microbiology, Children’s Hospital of Tunis, Boulevard 9 April, Tunis 1006, Tunisia
Hager Battikh
Microbiology Laboratory, Rabta University Hospital, Rue Jabbari, Tunis 1007, Tunisia
Besma Mnif
Laboratory of Microbiology, Habib Bourguiba University Hospital, Route de l’Ain, Sfax 3000, Tunisia
Manel Hamdoun
Aziza Othmana Hospital, Laboratoire de Microbiologie-Biochimie, Bab Menara Tunis 1008, Tunisia
Yosra Chebbi
National Bone Marrow Transplant Center, Laboratory Ward, Tunis Rue Djebal Lakhdar 1006, Tunisia
Lamia Kanzari
Faculty of Medicine of Tunis, University of Tunis El Manar, LR99ES09, Tunis Rue Djebal Lakhdar 1006, Tunisia
Wafa Achour
National Bone Marrow Transplant Center, Laboratory Ward, Tunis Rue Djebal Lakhdar 1006, Tunisia
Olfa Bahri
Aziza Othmana Hospital, Laboratoire de Microbiologie-Biochimie, Bab Menara Tunis 1008, Tunisia
Adenene Hammami
Laboratory of Microbiology, Habib Bourguiba University Hospital, Route de l’Ain, Sfax 3000, Tunisia
Meriam Zribi
Microbiology Laboratory, Rabta University Hospital, Rue Jabbari, Tunis 1007, Tunisia
Hanen Smaoui
Laboratory of Microbiology, Children’s Hospital of Tunis, Boulevard 9 April, Tunis 1006, Tunisia
Ilhem Boutiba-Ben Boubaker
Faculty of Medicine of Tunis, University of Tunis El Manar, LR99ES09, Tunis Rue Djebal Lakhdar 1006, Tunisia
Background: Actually, no data on the prevalence of plasmid colistin resistance in Tunisia are available among clinical bacteria. Objectives: This study aimed to investigate the current epidemiology of colistin resistance and the spread of the mcr gene in clinical Gram-negative bacteria (GNB) isolated from six Tunisian university hospitals. Methods: A total of 836 GNB strains were inoculated on COL-R agar plates with selective screening agar for the isolation of GNB resistant to colistin. For the selected isolates, mcr genes, beta-lactamases associated-resistance genes and molecular characterisation were screened by PCRs and sequencing. Results: Colistin-resistance was detected in 5.02% (42/836) of the isolates and colistin-resistant isolates harboured an ESBL (blaCTX-M-15) and/or a carbapenemase (blaOXA-48, blaVIM) encoding gene in 45.2% of the cases. The mcr-1 gene was detected in four E. coli isolates (0.59%) causing urinary tract infections and all these isolates also contained the blaTEM-1 gene. The blaCTX-M-15 gene was detected in three isolates that also carried the IncY and IncFIB replicons. The genetic environment surrounding the mcr-carrying plasmid indicated the presence of pap-2 gene upstream mcr-1 resistance marker with unusual missing of ISApl1 insertion sequence. The Conclusions: This study reports the first description of the mcr-1 gene among clinical E. coli isolates in Tunisia and provides an incentive to conduct routine colistin susceptibility testing in GNB clinical isolates.
