Am J Perinatol 2014; 31(11): 975-982
DOI: 10.1055/s-0034-1370341
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Genotypic and Phenotypic Characterization of Invasive Neonatal Escherichia coli Clinical Isolates

Salika Mehreen Shakir
1  Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
,
Jessica Marie Goldbeck
1  Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
,
Denise Robison
2  Clinical Microbiology Laboratory, OU Medical Center, Oklahoma City, Oklahoma
,
Annette Marie Eckerd
1  Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
,
Susana Chavez-Bueno
1  Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
› Author Affiliations
Further Information

Publication History

13 September 2013

24 December 2013

Publication Date:
24 February 2014 (eFirst)

Abstract

Objectives The objective of this study was to describe the clinical characteristics of neonates with Escherichia coli bacteremia and the antibiotic resistance pattern of the bacterial isolates. We assessed the isolates' genetic relatedness and virulence phenotypic characteristics in vitro.

Study Design A total of 24 neonates with E. coli bacteremia were identified prospectively in a tertiary-care hospital. Clinical and antibiotic resistance data were investigated. The E. coli isolates were analyzed by multilocus sequence typing (MLST); the presence of the K1 capsule and their ability to invade intestinal epithelial cells were also assessed.

Results Most newborns were very low birth weight infants. Overall, 75% of the isolates were ampicillin resistant and 17% were gentamicin and tobramycin nonsusceptible. MLST determined sequence types 95 and 131 (ST95 and ST131) predominated, with ST131 becoming significantly more prevalent recently. The K1 capsule was present in 50% of the isolates. ST131 isolates and those producing bacteremia in newborns younger than 7 days showed a highly invasive phenotype.

Conclusion Resistance to antibiotics currently used empirically to treat newborns is present in bacteremia-producing E. coli. Clonal spread among newborns of multidrug-resistant E. coli is possible; therefore, continued surveillance is needed. Identification of additional virulence factors associated with increased invasion in neonatal E. coli strains is important and further studies are warranted.