Carbapenem-Resistant Enterobacteriaceae: A Major Prevalence Difference due to the High Performance of Carbapenemase Producers when compared to the Nonproducers

• Published in: Infection control and hospital epidemiology 2015-12, Vol.36 (12), p.1480-1482
• Main Author: Rodrigues Perez, Leandro Reus
• Format: Article
• Language: English
• Subjects: Brazil - epidemiology; Carbapenems - isolation & purification; CRE bacteria; Drug Resistance, Microbial; E coli; Enterobacteriaceae - isolation & purification; Enterobacteriaceae Infections - epidemiology; Humans; Intensive Care Units; Nursing; Polymerase chain reaction; Prevalence; Rectum - microbiology
• ISSN: 0899-823X; 1559-6834
• DOI: 10.1017/ice.2015.227

Two distinct paths evidence this phenotype: (1) resistance to carbapenems by any mechanism, including the production of an acquired carbapenemase or the production of extended spectrum β-lactamase (ESBL) or AmpC combined with porin-loss (carbapenem-resistant Enterobacteriaceae [CRE]) and (2) resistance to carbapenems by means of an acquired carbapenemase (carbapenemase-producing Enterobacteriaceae—CPE).1 A prevalence survey monitoring carbapenem resistance among Enterobacteriaceae, including rectal screens and clinical specimens, was performed in a tertiary hospital in southern Brazil between April 2013 and May 2015. Another 22 isolates (4.4%; 95% CI, 2.9–6.6) were negative for carbapenemase production (phenotypic and PCR).TABLE 1 Distribution and Identification of Enterobacterial Species Characterized as Carbapenem-Resistant Enterobacteriaceae among the 497 Samples (Rectal Screen and Clinical Specimens) Distribution (%; No./Total No.) Enterobacteriaceae species (%; No./Total No.) Carbapenemase Rectal screen Clinical Rectal screen Clinical Producersa 95.6 (475/497) 87.2 (184/211) Klebsiella pneumoniaeb (93.4; 464/497) K. oxytoca (0.6; 3/497) Citrobacter freundii (0.6; 3/497) Escherichia coli (0.6; 3/497) Serratia marcescens (0.4; 2/497) K. pneumoniaeb (94.6; 174/184) E. cloacae (2.2; 4/184) E. coli (1.6; 3/184) S. marcescens (1.6; 3/184) Nonproducers 4.4 (22/497) 12.8 (27/211) K. pneumoniae (90.9; 20/22) Enterobacter cloacae (9.1; 2/22) E. cloacae (66.7; 18/27) K. pneumoniae (29.6; 8/27) Providencia stuartii (3.7; 1/27) a blaKPC-2 was the sole carbapenemase gene detected; b A randomly selected sample of isolates (rectal swab, n=10 and clinical specimen, n=13) was typed by pulsed-field gel electrophoresis and showed the same macrorestriction profile of DNA. [...]this study demonstrates a major prevalence of carbapenemase producers compared with nonproducers as a CRE etiological agent in our institution.