Correction: ESBL Detection: Comparison of a Commercially Available Chromogenic Test for Third Generation Cephalosporine Resistance and Automated Susceptibility Testing in Enterobactericeae

There are errors in the fourth and fifth sentences of the Introduction. The correct sentences are: Enzymes termed “β-lactamases” cleave the β-lactam ring through hydrolysis and thereby prevent their interference with the transpeptidase activity of the “penicillin-binding proteins” [1]. Over the last decades point mutations in the β-lactamase genes changed the active site and extended the substrate spectrum [2,3,4].

There is an error in the penultimate sentence of the first paragraph in the Introduction. The correct sentence is: The spread of these enzymes is facilitated by their encoding on plasmids and represents the major cause for the increased resistance to broad-spectrum β-lactam antibiotics on in Enterobacteriaceae [6].

There is an error in the second sentence of the final paragraph of the Introduction. The correct sentence is: The principle of the βLACTA^TM test is based on the cleavage of the substrate HMRZ-86*, a chromogenic cephalosporine [25,26].

The third and fourth sentences of the final paragraph of the Introduction contain errors and have been incorrectly combined. The correct sentences are: This substrate, initially yellow, turns red in the presence of ß-lactamases that confer resistance to 3GC. Notably, HMRZ-86 is not hydrolyzed by acquired penicillinases (e.g. SHV-1, TEM-1) but processed by ESBL, acquired AmpC and carbapenemases (KPC and metallobetalactamases) [26,27].

In the Materials and Methods section, the fourth sentence under the “Bacterial isolates” heading is incorrect. The correct sentence is: Species identification was performed with VITEK-MS (bioMérieux S.A., Nuertingen, Germany).

In the Materials and Methods section, in the fifth sentence under the “Bacterial isolates” heading the ESBL screening agar should be specified as: ChromID^TM, bioMérieux S.A..

In the first sentence of the second paragraph under the “Susceptibility testing and detection of ESBL-E” heading of the Material and Methods section the VITEK2 manufacturer should be specified as: bioMérieux S.A., Nürtingen, Germany.

In the second sentence of the second paragraph under the “Susceptibility testing and detection of ESBL-E” heading of the Material and Methods section the ChromID^TM selective agar and the VITEK2 should both be labelled as products from: bioMérieux S.A., Nürtingen, Germany.

The final sentence in the second paragraph under the “Susceptibility testing and detection of ESBL-E” heading of the Material and Methods section is incorrect. The correct sentence is: Third generation cephalosporine resistance (3GC-R) was further screened by βLACTA^TM test following the manufacturer´s protocol (Bio-Rad, Marnes-la-Coquette, France).

Throughout the third paragraph under the “Susceptibility testing and detection of ESBL-E” heading of the Material and Methods section, incorrect symbols and characters follow the registered trademark symbol. The correct sentences are: For molecular typing bacterial DNA was isolated using UltraClean^® Microbial DNA Isolation Kit (MO BIO Laboratories, Carlsbad, California, USA). The PCR was carried out using the PN-Mix (GenID^® GmbH, Strassberg, Germany) and Taq DNA Polymerase (Thermo Fisher Scientific Inc., Waltham, Massachusetts, USA) on a Labcycler (SensoQuest GmbH, Göttingen, Germany). Reverse hybridization was performed using the respective biotinylated amplicons using the protocol from GenID^® GmbH, Straßberg, Germany with sequence-specific oligonucleotides for betalactamases and controls immobilized on nitrocellulose membranes.

The final sentence under the “Susceptibility testing and detection of ESBL-E” heading of the Material and Methods is incorrect. The correct sentence is: In those isolates tested negative in the molecular ESBL screen ESBL activity was confirmed using the disc diffusion method using AmpC&ESβL Detection Discs and Cefpodoxim ESβL ID Disc Set (both from Mast Diagnostica GmbH) and E-Test ESBL from bioMérieux S.A..

The fourth sentence of the penultimate paragraph of the Discussion section is incorrect. The correct sentence is: Notably, in VITEK2 analysis only 48.1% of ESBL-E displayed in vitro resistance to ceftazidime according to EUCAST criteria, e.g. MIC >4, while 39.2% of ESBL-E and 87.4% non-ESBL-E displayed MICs <4 (Fig 1) albeit an earlier study that the βLACTA^TM test was useful in discriminating ceftazidime-susceptible from resistant Pseudomonas aeruginosa isolates [36].

The fourth sentence of the penultimate paragraph of the Discussion section is incorrect. The correct sentence is: Notably, in VITEK2 analysis only 48.1% of ESBL-E displayed in vitro resistance to ceftazidime according to EUCAST criteria, e.g. MIC >4, while 39.2% of ESBL-E and 87.4% non-ESBL-E displayed MICs <4 (Fig. 1) albeit an earlier study that the βLACTA^TM test was useful in discriminating ceftazidime-susceptible from–resistant Pseudomonas aeruginosa isolates [36].