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Disk Carbapenemase Test for the Rapid Detection of KPC-, NDM-, and Other Metallo- β -Lactamase-Producing Gram-Negative Bacilli

View Article: PubMed Central - PubMed

ABSTRACT

Background: Rapid detection of carbapenemase-producing gram-negative bacilli (GNB) is required for optimal treatment of infected patients. We developed and assessed a new disk carbapenemase test (DCT).

Methods: Paper disks containing 0.3 mg of imipenem and bromothymol blue indicator were developed, and the performance of the DCT were evaluated by using 742 strains of GNB with or without carbapenemases.

Results: The paper disks were simple to prepare, and the dried disks were stable at -20℃ and at 4℃. The DCT detected 212 of 215 strains (98.6% sensitivity with 95% confidence interval [CI] 96.0-99.5%) of GNB with known class A (KPC and Sme) and class B (NDM, IMP, VIM, and SIM) carbapenemases within 60 min, but failed to detect GES-5 carbapenemase. The DCT also detected all two Escherichia coli isolates with OXA-48, but failed to detect GNB with OXA-232, and other OXA carbapenemases. The DCT showed 100% specificity (95% CI, 99.2-100%) in the test of 448 imipenem-nonsusceptible, but carbapenemase genes not tested, clinical isolates of GNB.

Conclusions: The DCT is simple and can be easily performed, even in small laboratories, for the rapid detection of GNB with KPC, NDM and the majority of IMP, VIM, and SIM carbapenemases.

No MeSH data available.


Related in: MedlinePlus

Examples of disk carbapenemase tests (A) and inhibition tests (B) showing the color of the disks at indicated times. Isolates were (1) Acinetobacter junii (AJU) 13/6/R1783; (2) Acinetobacter baumannii (ABA) 11/6/R2498; (3) A. baumannii 03/9/T104; (4) Acinetobacter nosocomialis (ANO) 15/4/B6548; (5) Pseudomonas aeruginosa (PAE) 11/11/U1203; (6) P. aeruginosa 97/143; (7) P. aeruginosa 95/1/704; (8) A. baumannii 15/1694; (9) Escherichia coli (ECO) 12/2/P57; (10) E. coli KD-1251; (11) Klebsiella pneumoniae (KPN) M0801, and (12) E. coli 15/5/141. Positive reactions progressed from greenish yellow to yellow. All KPC- and NDM-producing isolates showed fast and strong reactions, and the color progressed to orange yellow. An A. baumannii isolate with VIM-2 (2), a P. aeruginosa isolate with VIM-1 (6), and an E. coli isolate with OXA-48 (12) showed slow and weak reactions. A. baumannii with OXA-23 (8) did not show a positive reaction within 60 min. Panel B is an example of inhibition by 1,000 µg of TZ (or by 1,000 µg of TZ in PTZ) and 60 mM EDTA.Abbreviations: PTZ, piperacillin-tazobactam; TZ, tazobactam.
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Figure 1: Examples of disk carbapenemase tests (A) and inhibition tests (B) showing the color of the disks at indicated times. Isolates were (1) Acinetobacter junii (AJU) 13/6/R1783; (2) Acinetobacter baumannii (ABA) 11/6/R2498; (3) A. baumannii 03/9/T104; (4) Acinetobacter nosocomialis (ANO) 15/4/B6548; (5) Pseudomonas aeruginosa (PAE) 11/11/U1203; (6) P. aeruginosa 97/143; (7) P. aeruginosa 95/1/704; (8) A. baumannii 15/1694; (9) Escherichia coli (ECO) 12/2/P57; (10) E. coli KD-1251; (11) Klebsiella pneumoniae (KPN) M0801, and (12) E. coli 15/5/141. Positive reactions progressed from greenish yellow to yellow. All KPC- and NDM-producing isolates showed fast and strong reactions, and the color progressed to orange yellow. An A. baumannii isolate with VIM-2 (2), a P. aeruginosa isolate with VIM-1 (6), and an E. coli isolate with OXA-48 (12) showed slow and weak reactions. A. baumannii with OXA-23 (8) did not show a positive reaction within 60 min. Panel B is an example of inhibition by 1,000 µg of TZ (or by 1,000 µg of TZ in PTZ) and 60 mM EDTA.Abbreviations: PTZ, piperacillin-tazobactam; TZ, tazobactam.

Mentions: Immediately after the transfer of colonies, the color of the DCT disks was typically green, but was a more alkaline greenish blue with the Acinetobacter spp. A carbapenemase-positive reaction started with a greenish yellow color that progressed to yellow, and even to orange yellow (Fig. 1).


Disk Carbapenemase Test for the Rapid Detection of KPC-, NDM-, and Other Metallo- β -Lactamase-Producing Gram-Negative Bacilli
Examples of disk carbapenemase tests (A) and inhibition tests (B) showing the color of the disks at indicated times. Isolates were (1) Acinetobacter junii (AJU) 13/6/R1783; (2) Acinetobacter baumannii (ABA) 11/6/R2498; (3) A. baumannii 03/9/T104; (4) Acinetobacter nosocomialis (ANO) 15/4/B6548; (5) Pseudomonas aeruginosa (PAE) 11/11/U1203; (6) P. aeruginosa 97/143; (7) P. aeruginosa 95/1/704; (8) A. baumannii 15/1694; (9) Escherichia coli (ECO) 12/2/P57; (10) E. coli KD-1251; (11) Klebsiella pneumoniae (KPN) M0801, and (12) E. coli 15/5/141. Positive reactions progressed from greenish yellow to yellow. All KPC- and NDM-producing isolates showed fast and strong reactions, and the color progressed to orange yellow. An A. baumannii isolate with VIM-2 (2), a P. aeruginosa isolate with VIM-1 (6), and an E. coli isolate with OXA-48 (12) showed slow and weak reactions. A. baumannii with OXA-23 (8) did not show a positive reaction within 60 min. Panel B is an example of inhibition by 1,000 µg of TZ (or by 1,000 µg of TZ in PTZ) and 60 mM EDTA.Abbreviations: PTZ, piperacillin-tazobactam; TZ, tazobactam.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940486&req=5

Figure 1: Examples of disk carbapenemase tests (A) and inhibition tests (B) showing the color of the disks at indicated times. Isolates were (1) Acinetobacter junii (AJU) 13/6/R1783; (2) Acinetobacter baumannii (ABA) 11/6/R2498; (3) A. baumannii 03/9/T104; (4) Acinetobacter nosocomialis (ANO) 15/4/B6548; (5) Pseudomonas aeruginosa (PAE) 11/11/U1203; (6) P. aeruginosa 97/143; (7) P. aeruginosa 95/1/704; (8) A. baumannii 15/1694; (9) Escherichia coli (ECO) 12/2/P57; (10) E. coli KD-1251; (11) Klebsiella pneumoniae (KPN) M0801, and (12) E. coli 15/5/141. Positive reactions progressed from greenish yellow to yellow. All KPC- and NDM-producing isolates showed fast and strong reactions, and the color progressed to orange yellow. An A. baumannii isolate with VIM-2 (2), a P. aeruginosa isolate with VIM-1 (6), and an E. coli isolate with OXA-48 (12) showed slow and weak reactions. A. baumannii with OXA-23 (8) did not show a positive reaction within 60 min. Panel B is an example of inhibition by 1,000 µg of TZ (or by 1,000 µg of TZ in PTZ) and 60 mM EDTA.Abbreviations: PTZ, piperacillin-tazobactam; TZ, tazobactam.
Mentions: Immediately after the transfer of colonies, the color of the DCT disks was typically green, but was a more alkaline greenish blue with the Acinetobacter spp. A carbapenemase-positive reaction started with a greenish yellow color that progressed to yellow, and even to orange yellow (Fig. 1).

View Article: PubMed Central - PubMed

ABSTRACT

Background: Rapid detection of carbapenemase-producing gram-negative bacilli (GNB) is required for optimal treatment of infected patients. We developed and assessed a new disk carbapenemase test (DCT).

Methods: Paper disks containing 0.3 mg of imipenem and bromothymol blue indicator were developed, and the performance of the DCT were evaluated by using 742 strains of GNB with or without carbapenemases.

Results: The paper disks were simple to prepare, and the dried disks were stable at -20℃ and at 4℃. The DCT detected 212 of 215 strains (98.6% sensitivity with 95% confidence interval [CI] 96.0-99.5%) of GNB with known class A (KPC and Sme) and class B (NDM, IMP, VIM, and SIM) carbapenemases within 60 min, but failed to detect GES-5 carbapenemase. The DCT also detected all two Escherichia coli isolates with OXA-48, but failed to detect GNB with OXA-232, and other OXA carbapenemases. The DCT showed 100% specificity (95% CI, 99.2-100%) in the test of 448 imipenem-nonsusceptible, but carbapenemase genes not tested, clinical isolates of GNB.

Conclusions: The DCT is simple and can be easily performed, even in small laboratories, for the rapid detection of GNB with KPC, NDM and the majority of IMP, VIM, and SIM carbapenemases.

No MeSH data available.


Related in: MedlinePlus