PDF
ePub
Citation
Print
Abstract
Enterobacteriaceae is a family of gram-negative, rod-shaped bacteria that consists of various species. Among these, members of the genus Cedecea has been reported as relatively rare causative pathogens of human infections. Commercially available automated identification systems that use biochemical reactions are known to accurately identify Enterobacteriaceae species. However, the accurate identification of some organisms with diverse biochemical profiles by these automated identification systems may be problematic. In this study, we report two cases of isolate misidentification, from patients with acute cholecystitis and deep vein thrombosis, as Cedecea davisae with VITEK II system. Both the isolates were correctly identified as Enterobacter hormaechei using gyrB gene sequence analysis. We also performed 16S rRNA sequence analyses and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses; however, indeterminate results were obtained from both the assays. Therefore, the sequence analysis of alternative genes, like gyrB, might be useful for accurate identification of species that belong to the family of Enterobacteriaceae.
Figures and Tables
Table 1
Results of 16S rRNA sequencing
Table 2
Results of MALDI-TOF MS identification
Table 3
Results of rpoB sequencing
Table 4
Results of gyrB sequencing
References
1. Sanders WE Jr, Sanders CC. Enterobacter spp.: pathogens poised to flourish at the turn of the century. Clin Microbiol Rev. 1997; 10:220–241.
2. Ling TK, Liu ZK, Cheng AF. Evaluation of the VITEK 2 system for rapid direct identification and susceptibility testing of gram-negative bacilli from positive blood cultures. J Clin Microbiol. 2003; 41:4705–4707.
3. Delmas J, Breysse F, Devulder G, Flandrois JP, Chomarat M. Rapid identification of Enterobacteriaceae by sequencing DNA gyrase subunit B encoding gene. Diagn Microbiol Infect Dis. 2006; 55:263–268.
4. O'Hara CM, Steigerwalt AG, Hill BC, Farmer JJ 3rd, Fanning GR, Brenner DJ. Enterobacter hormaechei, a new species of the family Enterobacteriaceae formerly known as enteric group 75. J Clin Microbiol. 1989; 27:2046–2049.
5. Wenger PN, Tokars JI, Brennan P, Samel C, Bland L, Miller M, et al. An outbreak of Enterobacter hormaechei infection and colonization in an intensive care nursery. Clin Infect Dis. 1997; 24:1243–1244.
6. Campos LC, Lobianco LF, Seki LM, Santos RM, Asensi MD. Outbreak of Enterobacter hormaechei septicaemia in newborns caused by contaminated parenteral nutrition in Brazil. J Hosp Infect. 2007; 66:95–97.
7. Bae BH, Sureka SB. Cedecea davisae isolated from scrotal abscess. J Urol. 1983; 130:148–149.
8. Perkins SR, Beckett TA, Bump CM. Cedecea davisae bacteremia. J Clin Microbiol. 1986; 24:675–676.
9. Abate G, Qureshi S, Mazumder SA. Cedecea davisae bacteremia in a neutropenic patient with acute myeloid leukemia. J Infect. 2011; 63:83–85.
10. Townsend SM, Hurrell E, Caubilla-Barron J, Loc-Carrillo C, Forsythe SJ. Characterization of an extended-spectrum beta-lactamase Enterobacter hormaechei nosocomial outbreak, and other Enterobacter hormaechei misidentified as Cronobacter (Enterobacter) sakazakii. Microbiology. 2008; 154:3659–3667.
11. Mollet C, Drancourt M, Raoult D. rpoB sequence analysis as a novel basis for bacterial identification. Mol Microbiol. 1997; 26:1005–1011.
12. van Baar BL. Characterisation of bacteria by matrix-assisted laser desorption/ionisation and electrospray mass spectrometry. FEMS Microbiol Rev. 2000; 24:193–219.
13. Pavlovic M, Konrad R, Iwobi AN, Sing A, Busch U, Huber I. A dual approach employing MALDI-TOF MS and real-time PCR for fast species identification within the Enterobacter cloacae complex. FEMS Microbiol Lett. 2012; 328:46–53.
14. Ohad S, Block C, Kravitz V, Farber A, Pilo S, Breuer R, et al. Rapid identification of Enterobacter hormaechei and Enterobacter cloacae genetic cluster III. J Appl Microbiol. 2014; 116:1315–1321.
XML Download