%0 Journal Article %1 samuelsen_evaluation_2008 %A Samuelsen, Orjan %A Buarø, Liselotte %A Giske, Christian G %A Simonsen, Gunnar S %A Aasnaes, Bettina %A Sundsfjord, Arnfinn %D 2008 %J The Journal of Antimicrobial Chemotherapy %K Bacterial Bacterial, Chain Humans, Imipenem, Infections, Microbial Polymerase Predictive Proteins, Pseudomonas Reaction, Resistance, Sensitivity Specificity, Spectrophotometry Tests, Value aeruginosa, and of {DNA,} {beta-Lactamases,} {beta-Lactam} %N 4 %P 827--30 %R dkn016 %T Evaluation of phenotypic tests for the detection of metallo-beta-lactamase-producing Pseudomonas aeruginosa in a low prevalence country %U http://www.ncbi.nlm.nih.gov/pubmed/18227087 %V 61 %X OBJECTIVES: To evaluate four phenotypic tests for the detection of metallo-beta-lactamase (MBL) production in Pseudomonas aeruginosa in a low MBL prevalence setting. METHODS: Sixty clinical isolates of P. aeruginosa resistant to imipenem and/or meropenem and seven MBL-positive control strains were examined by: (i) MBL Etest; (ii) combined imipenem discs supplemented with EDTA (IPM-EDTA); (iii) beta-lactam discs on dipicolinic acid plates (DF-DIPI); and (iv) the Cica-beta test. Spectrophotometric analysis of crude cell extracts for imipenem hydrolysis along with consensus PCRs for bla(VIM) and bla(IMP) was used as reference methods. RESULTS: Two clinical isolates (3\%) were MBL-positive. The MBL Etest and IPM-EDTA test scored positive for all MBL-positive isolates, but showed specificities of 86\% and 91\%, and positive predictive values (PPVs) of only 20\% and 29\%, respectively. Adding resistance to ceftazidime (MIC \textgreater8 mg/L) as a criterion for MBL testing would reduce the number of isolates to be screened by 50\% and increase the PPVs of the MBL Etest and IMP-EDTA test to 29\% and 40\%, respectively. The Cica-beta test correctly identified all MBL-negative isolates, but misidentified one MBL-positive clinical isolate as an extended-spectrum beta-lactamase (ESBL)-producer and one as inconclusive (producing multiple beta-lactamases). No reliable breakpoints could be defined for the DF-DIPI test due to overlapping inhibition zone diameters for MBL-positive and -negative isolates. CONCLUSIONS: None of the phenotypic tests were optimal due to low sensitivity or specificity, resulting in low PPVs. Including ceftazidime resistance to the MBL-screening criteria would significantly improve the performance of the MBL Etest and IPM-EDTA disc test.

@article{samuelsen_evaluation_2008, abstract = {{OBJECTIVES:} To evaluate four phenotypic tests for the detection of metallo-beta-lactamase {(MBL)} production in Pseudomonas aeruginosa in a low {MBL} prevalence setting. {METHODS:} Sixty clinical isolates of P. aeruginosa resistant to imipenem and/or meropenem and seven {MBL-positive} control strains were examined by: (i) {MBL} Etest; (ii) combined imipenem discs supplemented with {EDTA} {(IPM-EDTA);} (iii) beta-lactam discs on dipicolinic acid plates {(DF-DIPI);} and (iv) the Cica-beta test. Spectrophotometric analysis of crude cell extracts for imipenem hydrolysis along with consensus {PCRs} for {bla(VIM)} and {bla(IMP)} was used as reference methods. {RESULTS:} Two clinical isolates (3\%) were {MBL-positive.} The {MBL} Etest and {IPM-EDTA} test scored positive for all {MBL-positive} isolates, but showed specificities of 86\% and 91\%, and positive predictive values {(PPVs)} of only 20\% and 29\%, respectively. Adding resistance to ceftazidime {(MIC} {\textgreater}8 {mg/L)} as a criterion for {MBL} testing would reduce the number of isolates to be screened by 50\% and increase the {PPVs} of the {MBL} Etest and {IMP-EDTA} test to 29\% and 40\%, respectively. The Cica-beta test correctly identified all {MBL-negative} isolates, but misidentified one {MBL-positive} clinical isolate as an extended-spectrum beta-lactamase {(ESBL)-producer} and one as inconclusive (producing multiple beta-lactamases). No reliable breakpoints could be defined for the {DF-DIPI} test due to overlapping inhibition zone diameters for {MBL-positive} and -negative isolates. {CONCLUSIONS:} None of the phenotypic tests were optimal due to low sensitivity or specificity, resulting in low {PPVs.} Including ceftazidime resistance to the {MBL-screening} criteria would significantly improve the performance of the {MBL} Etest and {IPM-EDTA} disc test.}, added-at = {2011-03-11T10:05:34.000+0100}, author = {Samuelsen, Orjan and Buarø, Liselotte and Giske, Christian G and Simonsen, Gunnar S and Aasnaes, Bettina and Sundsfjord, Arnfinn}, biburl = {https://www.bibsonomy.org/bibtex/243415b5dc6a08ff82e4664b4e7e661f0/jelias}, doi = {dkn016}, interhash = {fa192da31e22fe02efece05bdb2cdca2}, intrahash = {43415b5dc6a08ff82e4664b4e7e661f0}, issn = {1460-2091}, journal = {The Journal of Antimicrobial Chemotherapy}, keywords = {Bacterial Bacterial, Chain Humans, Imipenem, Infections, Microbial Polymerase Predictive Proteins, Pseudomonas Reaction, Resistance, Sensitivity Specificity, Spectrophotometry Tests, Value aeruginosa, and of {DNA,} {beta-Lactamases,} {beta-Lactam}}, month = apr, note = {{PMID:} 18227087}, number = 4, pages = {827--30}, timestamp = {2011-03-11T10:06:41.000+0100}, title = {Evaluation of phenotypic tests for the detection of metallo-beta-lactamase-producing Pseudomonas aeruginosa in a low prevalence country}, url = {http://www.ncbi.nlm.nih.gov/pubmed/18227087}, volume = 61, year = 2008 }