title: Outbreak of Salmonella enterica serotype Infantis producing ArmA 16S RNA methylase and CTX-M-15 extended-spectrum β-lactamase in a neonatology ward in Constantine, Algeria.
abstract: Plasmid-mediated 16S rRNA methylases such as ArmA, which confer high levels of resistance to aminoglycosides, are increasingly reported in Enterobacteriaceae. This study investigated the molecular mechanism of β-lactam and aminoglycoside resistance in extended-spectrum β-lactamase (ESBL)-producing Salmonella enterica serotype Infantis isolated at the 53-bed neonatology ward of University Hospital Benabib in Constantine, Algeria. From September 2008 to January 2009, 200 S. enterica isolates were obtained from 138 patients (age range 8-80 months) hospitalised in the neonatology ward. Most isolates were from stool cultures, but also from two blood cultures and one gastric fluid. The isolates were multidrug-resistant and produced TEM-1 and CTX-M-15 enzymes as well as the 16S RNA methylase ArmA. The armA, bla(CTX-M-15) and bla(TEM-1) genes were located on the same 140-kb self-transferable plasmid belonging to the IncL/M incompatibility group. All of the S. Infantis isolates belonged to a single clone. Increased infection control measures and thorough biodecontamination of the rooms led to control of the outbreak but did not eradicate the epidemic strain. This study further illustrates the global emergence of ArmA methylase and its frequent association with bla(CTX-M) genes. Spread of 16S RNA methylase determinants at the same level as bla(CTX-M) genes in Enterobacteriaceae may seriously compromise the efficacy of aminoglycosides for treating Gram-negative infections.
authors.affiliation: Service de Bactériologie-Virologie, INSERM U914: Emerging Resistance to Antibiotics, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, 94275 Le Kremlin-Bicêtre, Faculté de Médecine, Université Paris-Sud, France. thierry.naas@bct.ap-hop-paris.fr
authors.forename: Thierry
authors.initials: T
authors.lastname: Naas
authors.forename: Chafia
authors.initials: C
authors.lastname: Bentchouala
authors.forename: Gaelle
authors.initials: G
authors.lastname: Cuzon
authors.forename: Sanàa
authors.initials: S
authors.lastname: Yaou
authors.forename: Abdesselam
authors.initials: A
authors.lastname: Lezzar
authors.forename: Farida
authors.initials: F
authors.lastname: Smati
authors.forename: Patrice
authors.initials: P
authors.lastname: Nordmann
mesh_terms: D000462:Algeria / Q000453:epidemiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001769:Blood / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial; D005243:Feces / Q000382:microbiology; D005750:Gastric Juice / Q000382:microbiology; D005838:Genotype; D006760:Hospitalization; D006801:Humans; D007223:Infant; D058889:Molecular Typing; D010957:Plasmids / Q000032:analysis; D012480:Salmonella Infections / Q000453:epidemiology* / Q000382:microbiology*; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics*; D012359:tRNA Methyltransferases / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D012359:tRNA Methyltransferases; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases