Comparison of Three Biochemical Tests for Rapid Detection of Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae

Abstract

dEnterobacterial isolates producing clavulanic-inhibited extended-spectrum ␤-lactamases (ESBLs) are increasingly spreading in the community and are often responsible for nosocomial infections. Rapid biochemical tests have been developed recently for their detection. Three tests, namely, the Rapid ESBL NDP test, the ␤-Lacta test, and the Rapid ESBL Screen, have been evaluated with a collection of 108 well-characterized strains, including wild-type strains, strains producing ESBLs, overexpressed cephalosporinases, and carbapenemases. The ESBL NDP test and the Rapid ESBL Screen (a copy of the ESBL NDP test) are aimed at detecting ESBL producers, while the ␤-Lacta test is aimed at detecting not only ESBL producers but also cephalosporinase and carbapenemase producers. The sensitivity and specificity for detecting ESBL producers (n ‫؍‬ 60) were 95% and 100% for the Rapid ESBL NDP test, 80% and 87% (after 30 min) and 92% and 83% (after 2 h) for the Rapid ESBL Screen, and 88% and 71% for the ␤-Lacta test, respectively. Varied and time-consuming detection (up to 2 h) of ESBLs by the Rapid ESBL Screen and concomitant and varied detection of producers of AmpC and several types of carbapenemases correspond to significant shortcomings of using the Rapid Screen ESBL and ␤-Lacta tests, respectively.A cquired resistance to broad-spectrum cephalosporins in Enterobacteriaceae is mainly due to the production of clavulanic acid-inhibited extended-spectrum ␤-lactamases (ESBLs), which have extensively disseminated worldwide (1). Along with carbapenemase producers, ESBL producers represent the most important resistance trait in Enterobacteriaceae in 2015. The European Antimicrobial Resistance Surveillance System Network (EARSNet), which includes 30 European countries, reported in 2013 the prevalence rates of nonsusceptibility to broad-spectrum cephalosporins among invasive enterobacterial isolates (2). The proportion of Escherichia coli strains resistant to broad-spectrum cephalosporins ranged from 5% to 39.6%, depending on the country. In Klebsiella pneumoniae, the percentage of resistance to broad-spectrum cephalosporins showed a significant increase from 22.8% in 2012 to 30% in 2013, encompassing 85 to 100% of the ESBL producers. In the United States, the percentages of health care-associated infections caused by broad-spectrum cephalosporin-resistant Enterobacteriaceae have been estimated to be 14% and 23% for E. coli and Klebsiella spp., respectively (http://www.cdc.gov /drugresistance/threat-report-2013). Those ESBL-producing Enterobacteriaceae are identified either as a source of hospital-or community-acquired infections (3).The rapid detection of ESBL producers is therefore crucial in order to prevent their dissemination and to guide the treatments of infected patients. Several phenotypic techniques are based on the inhibition of ESBL activity by clavulanic acid or tazobactam. Those techniques require a preliminary growth step of 24 to 48 h (4). Molecular detection of ESBL-coding genes is interesting but remains costly, requi...

Resistance Patterns and Phenotypic Detection of β-lactamase Enzymes among Enterobacteriaceae Isolates from Referral Hospitals in Khartoum State, Sudan

“…Enterobacteriaceae isolates are increasingly spreading over the hospital settings and frequently responsible for most of the nosocomial and community-acquired infections [14]. In the present study, most of the isolates were recovered from urine samples and wound discharge.…”

How Should We Treat Hospital-Acquired and Ventilator-Associated Pneumonia Caused by Extended-Spectrum β-Lactamase–Producing Enterobacteriaceae?

“…48 It is also possible, on the bronchial specimen culture (i.e., after 24 hours), to obtain rapid detection of enzymes such as extended-spectrum β-lactamases, AmpC, and carbapenemases within 15 minutes to 2 hours using biochemical techniques ( $90% sensitivity and $90% specificity). 45,49 Available Targeted Treatment for Severe ESBL-PE Infections…”

Analysis of the Degradation of Broad-Spectrum Cephalosporins by OXA-48-Producing Enterobacteriaceae Using MALDI-TOF MS

“…However, the fact that hydrolysis of cefotaxime is not complete can explain why OXA-48-producing enterobacterial isolates remain phenotypically susceptible to cefotaxime in vitro. Activity on cefotaxime can also explain the eventual positive results obtained by colorimetric assays based on pH reduction, aimed at ESBL detection [15,16], which could be due to carboxyl-acid formation after hydrolysis of the beta-lactam ring. From a clinical point of view, the efficacy of cefotaxime against OXA-48-producing Enterobacteriaceae could be impaired by the aforementioned hydrolysis and this is consistent with the previously reported lower efficacy of this drug in vivo with respect to ceftazidime or cefepime [8,9].…”