title: Outbreak of a novel Enterobacter sp. carrying blaCTX-M-15 in a neonatal unit of a tertiary care hospital in Tanzania.
abstract: Enterobacter hormaechei and Cronobacter sakazakii are amongst the most important causes of outbreaks of neonatal sepsis associated with powdered milk. In this study, we report for the first time an outbreak of a novel Enterobacter sp. harbouring bla(CTX-M-15) in a neonatal unit in Tanzania. Seventeen Gram-negative enteric isolates from neonatal blood cultures were studied. Antibiotic susceptibility was assessed by disc diffusion testing, and the presence of the bla(CTX-M-15) gene was established by polymerase chain reaction (PCR) and sequencing. Isolates were typed by pulsed-field gel electrophoresis (PFGE). Identification by biochemical profiling was followed by nucleotide sequencing of 16S ribosomal DNA (rDNA), rpoB and hsp60 alleles. Environmental sampling was done and control measures were established. Isolates were initially misidentified based on their fermentation characteristics and agglutination as Salmonella enterica serotype Paratyphi. All isolates were resistant to multiple antibiotics, except for ciprofloxacin and carbapenems, and were found to harbour bla(CTX-M-15) on a 291-kb narrow-range plasmid. PFGE analysis indicated the clonal outbreak of a single strain, infecting 17 neonates with a case fatality rate of 35%. The same strain was isolated from a milk bucket. Phylogenetic analysis using 16S rDNA, rpoB and hsp60 sequences permitted no definitive identification, clustering the strains in the Enterobacter cloacae complex with similarities of 92-98.8%. The data describe an outbreak of a novel bla(CTX-M-15)-positive, multiresistant Enterobacter strain in an African neonatal unit that can easily be misidentified taxonomically. These data highlight the need for constant surveillance of bacteria harbouring extended-spectrum β-lactamases as well as improvements in hygiene measures in developing countries.
authors.affiliation: Weill Bugando University College of Health Sciences, P.O. Box 1464, Mwanza, Tanzania.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Mshana
authors.forename: Lisa
authors.initials: L
authors.lastname: Gerwing
authors.forename: Mercy
authors.initials: M
authors.lastname: Minde
authors.forename: Torsten
authors.initials: T
authors.lastname: Hain
authors.forename: Eugen
authors.initials: E
authors.lastname: Domann
authors.forename: Eligius
authors.initials: E
authors.lastname: Lyamuya
authors.forename: Trinad
authors.initials: T
authors.lastname: Chakraborty
authors.forename: Can
authors.initials: C
authors.lastname: Imirzalioglu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D001769:Blood / Q000382:microbiology; D018834:Chaperonin 60 / Q000235:genetics; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D004754:Enterobacter / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006761:Hospitals; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods; D008969:Molecular Sequence Data; D058889:Molecular Typing; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D018805:Sepsis / Q000453:epidemiology* / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013636:Tanzania / Q000453:epidemiology; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D018834:Chaperonin 60; D012336:RNA, Ribosomal, 16S; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases