First Report of CTX-M-15 in Salmonella enterica Serotype Kedougou Recovered From an Algerian Hospital

Abstract

To the Editors: Extended-spectrum β-lactamases (ESBLs) are uncommon in Salmonella enterica strains as compared with other enterobacterial species, such as Escherichia coli and Klebsiella pneumoniae.1 However, ESBL producing nontyphoïdal salmonellae are increasing in prevalence worldwide.2–4 In 2006, data from the Algerian System of Antimicrobial Resistance Surveillance in Algeria performed on K. pneumoniae, E. coli, Proteus sp, Enterobacter sp, S. marcescens, and Salmonella sp isolates collected from 18 hospitals, showed that the overall prevalence rates of Enterobacteriaceae producing ESBL was 22% and the frequency in K. pneumoniae, E. coli, Proteus sp, Enterobacter sp, S. marcescens, and Salmonella sp, may account, respectively, for 40.9%, 10%, 21.8%, 34.6%, 41%, and 4.8% (www.ands.dz/aarn/index.htm). Different CTX-M β-lactamases have been reported in S. enterica, CTX-M-15 in serotypes Typhimurium,4 Corvallis,2 and Kentucky3 and, in Algeria, a S. enterica serotype Senftenberg isolate producing CTX-M-3.1 In April 2007, a 5-day-old premature newborn (age of 28 weeks) was admitted to the Neonatology Unit of the University Hospital of Tizi Ouzou, Algeria, from another center, for acute septicemia. The patient was treated initially with a combination of cefotaxime, ampicillin, and gentamicin. This was subsequently changed after isolation of S. enterica serotype Kedougou from blood specimen. The patient was cured after intravenous administration of imipenem and amikacin. The isolate was identified with the API-20E system (Bio-Merieux, Marcy-l'Etoile, France) and by serotyping. Antimicrobial susceptibility testing was performed by a disc diffusion method on Mueller-Hinton agar (Bio-Rad) as described by the Antibiogram Committee of the French Society for Microbiology. The isolate was resistant to ticarcillin, piperacillin, cefotaxime, ceftazidime, cefepime, cefpirome, aztreonam, gentamicin, and tobramycin and remained susceptible to imipenem, cefoxitin, piperacillin-tazobactam, ticarcillinclavulanate, trimethoprim-sulfamethoxazole, amikacin, tetracycline, chloramphenicol, nalidixic acid, and fluoroquinolones. ESBL production was detected by the double-disk synergy test. PCR amplification were performed using 2 sets of primers: CTX-M-(-10F) (5′-AAGGAATCCCATGGTTAA-3′)/CTX-M-628R (5′-CCTTTCATCCATGTCACCA-3′) and CTX-M-405F (5′-GTGGCGATGAATAAGCTGA-3′)/CTX-M-879R (5′- CTATTACAAACCGTCGGTGA-3′). Sequencing of the entire coding region of blaCTX-M revealed the presence of CTX-M-15. The presence of ISEcp1 was investigated by a PCR assay. Sequencing of PCR products obtained revealed that the ISEcp1 element was located upstream of CTX-M-15. The are few reports of infection by S. enterica serotype Kedougou.5 This is the first report of a CTX-M-15 enzyme in S. enterica serotype Kedougou. The appearance of the CTX-M-15-producing S. enterica serotype Kedougou, and in others members of Enterobacteriaceae, in Algerian hospitals is a serious threat to public health. Abdelaziz Touati, MD Said Benallaoua, MD Alima Gharout, MD Laboratoire de microbiologie appliquée FSNV, Université A/MIRA de Béjaia Béjaia, Algérie Abdenour Ait Amar, MD Laboratoire de Microbiologie-Parasitologie CHU De Tizi Ouzou, Algérie Elizabeth Le Magrex Debar, MD Lucien Brasme, MD Jannick Madoux, MD Christophe De Champs, MD Laboratoire de Bactériologie-Virologie-Hygiène Hospitalière CHU Reims, UFR Médecine Université Reims Champagne Ardenne, France François-Xavier Weill, MD Centre National de Référence des Salmonella Unité de Biodiversité des Bactéries Pathogènes Emergentes Institut Pasteur 28 rue du Docteur Roux Paris cedex 15, France