Rapid detection of multidrug resistant Gram-negative bacilli by Cica-Beta-Test strips.
OBJECTIVE
This study aimed to evaluate the sensitivity and specificity of a new system (Cica-Beta-Test, Kanto Chemical, Japan) for rapid detection of AmpC-derepressed, extended-spectrum β-lactamases (ESβL) and metallo-β-lactamases (MβL).


METHODS
Two hundred Multi-Drug Resistant (MDR)-Gram-negative bacilli were studied: 170 Enterobacteriaceae and 30 Gram-negative non-fermentative bacteria. One hundred and eighteen strains produced an ESβL, seven MβL and 75 derepressed cephalosporinases. One drop of substrate was dispensed onto the filter pad of the Cica-Beta-Test strip. The bacterial colonies were spread on the filter pad of strip. The reading was performed after 2 to 15 min: turning chromogenic indicated the positive test. Three tests were used: Cica-Beta I for detection of MDR bacteria; Cica-Beta MβL for detection of MβL-producing bacteria and Cica-Beta CVA, which distinguish ESβL and AmpC-derepressed producers. Results were compared with molecular assays.


RESULTS
Cica-Beta-Test I has detected 194 MDR (sensitivity 97%), Cica-Beta-Test MβL has shown the presence of six MβL tested (sensitivity 85.7%). Five strains were non-MβL false positive (specificity 97.3%). Cica-Beta-Test CVA allowed the differentiation of ESβL-producing strains (109/115) and AmpC-derepressed strains (56/67) (sensitivity 94.8%, specificity 83.8%).


CONCLUSIONS
Because of their epidemic nature, the MDR strains are screened and require strict hygienic measures patients. The simultaneous use of three strips can quickly determine the presence of MDR including ESβL and MβL. Rapid screening of MDR avoids transmission and limits the use of broad-spectrum antibiotics.
Lavigne
J-P
JP
Institut national de la santé et de la recherche médicale, Espri 26, UFR de médecine, université Montpellier 1, 30908 Nîmes cedex 08, France; Laboratoire de bactériologie, virologie, CHU Carémeau, place du Professeur-Robert-Debré, 30029 Nîmes cedex 09, France.
Pfeiffer
C
C
Vidal
L
L
Sotto
A
A
D001426:Bacterial Proteins / Q000032:analysis*; D018550:Cephalosporin Resistance; D002510:Cephalosporinase / Q000032:analysis; D002863:Chromogenic Compounds; D024901:Drug Resistance, Multiple, Bacterial; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D008667:Metalloproteins / Q000032:analysis; D008826:Microbial Sensitivity Tests / Q000295:instrumentation*; D011934:Reagent Strips; D012680:Sensitivity and Specificity; D013997:Time Factors; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000032:analysis* / Q000145:classification
D001426:Bacterial Proteins; D002863:Chromogenic Compounds; D008667:Metalloproteins; D011934:Reagent Strips; D002510:Cephalosporinase; C048795:AmpC beta-lactamases; D001618:beta-Lactamases; C063912:carbapenemase