Evaluation of Meropenem, Imipenem and Ertapenem Impregnated MacConkey Agar Plates for the Detection of Carbapenem Resistant Enterobacteriaceae
Keywords:blaKPC, blaOXA-48, Meropenem Agar (Mac-Mem), Carbapenemase, Palestine
Background: Rapid detection of carbapenem resistant bacteria, in particular, members of the Enterobacteriaceae family (CRE), is of utmost importance for the management of infected or colonized patients.
Methods: Three carbapenems; meropenem, imipenem and ertapenem, with two different concentrations (0.5 mg/ml and 1.0 mg/ml), were impregnated in MacConkey agar. The carbapenem impregnated MacConkey agar plates; ([Mac-Mem], [Mac-Imp] and [Mac-Ert]), were then evaluated for the detection of carbapenem resistant Gram-negative bacteria in particular the blaKPC producing Enterobacteriaceae. The Limit of Detection (LOD) of the plates was determined after counting the colonies that grew on the plates after serial logarithmic dilutions of ten. Carbapenem resistant Gram-negative bacteria were prepared in normal saline, inoculated on the different plates and incubated at 35oC for 18-24 hours. The specificity and the shelf-life of the plates were determined by challenging the plates with six ESBL positive members of the Enterobacteriaceae family (K. pneumoniae, Salmonella species, Shigella species, E. coli, Proteus species and Citrobacter species) and one Enterobacter species with the blaAmpC phenotype. Finally, the MacConkey agar plates impregnated with 0.5 mg/ml meropenem were further challenged by incorporating them in the routine Caritas Baby Hospital active surveillance program for the detection of carbapenem resistant bacteria.
Results: Of the three carbapenems impregnated plates, Mac-Ert plates gave the lowest number of colony forming units (CFUâ€™s) detected regardless of the concentration of the antibiotic used. This was followed by the Mac-Mem plates which showed an LOD of less than 200 CFUâ€™s for most of the blaKPC positive bacteria tested at both antibiotic concentrations. The worst performance was noted for the Mac-Imp plate regardless of the antibiotic concentration used as a number of carbapenem resistant bacterial strains failed to grow on the plate. The Mac-Mem plates showed the best specificity as none of the ESBL and blaAmpC positive isolates grew on the plates at either antibiotic concentration tested after 18-24hours incubation in ambient air at 35oC. On the other hand, the Mac-Ert plates failed to inhibit the growth of the Citrobacter species tested at both antibiotic concentrations and the Proteus species tested at the 0.5Âµg/ml antibiotic concentration. The Mac-Imp plates showed poor specificity as both concentrations failed to inhibit the growth of the Proteus, Enterobacter and Citrobacter species evaluated after 18-24 hours incubation in ambient air at 35oC. Of all the plates tested, the 0.5 Âµg/ml Mac-Mem agar had the best shelf-life of up to one month at 4-8oC.Conclusions: The high specificity and the good selectivity, in addition to the long shelf-life allowed the 0.5Âµg/ml Mac-Mem agar to be used as a cost effective selective medium for the isolation of carbapenem resistant Gram-negative bacteria, in particular the blaKPC producing members of the Enterobacteriaceae family.
Nordmann P, Cuzon G, Naas T. The real threat of Klebsiella pneumoniae carbapenemase-producing bacteria. Lancet Infect Dis. 2009 Apr;9(4):228-36.
Queenan AM, Bush K. Carbapenemases: the versatile beta-lactamases. Clin Microbiol Rev. 2007 Jul;20(3):440-58, table of contents.
CDC. Guidance for control of infections with carbapenem-resistant or carbapenemase-producing Enterobacteriaceae in acute care facilities. MMWR Morb Mortal Wkly Rep. 2009 Mar 20;58(10):256-60.
Wiener-Well Y, Rudensky B, Yinnon AM, Kopuit P, Schlesinger Y, Broide E, et al. Carriage rate of carbapenem-resistant Klebsiella pneumoniae in hospitalised patients during a national outbreak. J Hosp Infect. 2010 Apr;74(4):344-9.
Buehlmann M, Fankhauser H, Laffer R, Bregenzer T, Widmer AF. The inguinal skin: an important site of colonization with extended-spectrum beta-lactamase-producing Enterobacteriaceae. Infect Control Hosp Epidemiol. 2010 Apr;31(4):427-8.
Calfee D, Jenkins SG. Use of active surveillance cultures to detect asymptomatic colonization with carbapenem-resistant Klebsiella pneumoniae in intensive care unit patients. Infect Control Hosp Epidemiol. 2008 Oct;29(10):966-8.
Ben-David D, Maor Y, Keller N, Regev-Yochay G, Tal I, Shachar D, et al. Potential role of active surveillance in the control of a hospital-wide outbreak of carbapenem-resistant Klebsiella pneumoniae infection. Infect Control Hosp Epidemiol. 2010 Jun;31(6):620-6.
Munoz-Price LS, De La Cuesta C, Adams S, Wyckoff M, Cleary T, McCurdy SP, et al. Successful eradication of a monoclonal strain of Klebsiella pneumoniae during a K. pneumoniae carbapenemase-producing K. pneumoniae outbreak in a surgical intensive care unit in Miami, Florida. Infect Control Hosp Epidemiol. 2010 Oct;31(10):1074-7.
CDC. Multiplex Real-Time PCR Detection of Klebsiella pneumoniae Carbapenemase (KPC) and New Delhi metallo-Î²-lactamase (NDM-1). CDC 2011 [cited; Available from: http://www.cdc.gov/HAI/pdfs/labSettings/KPC-NDM-protocol-2011.pdf]
Hindiyeh M, Smollen G, Grossman Z, Ram D, Davidson Y, Mileguir F, et al. Rapid detection of blaKPC carbapenemase genes by real-time PCR. J Clin Microbiol. 2008 Sep;46(9):2879-83.
Hindiyeh M, Smollan G, Grossman Z, Ram D, Robinov J, Belausov N, et al. Rapid detection of blaKPC carbapenemase genes by internally controlled real-time PCR assay using bactec blood culture bottles. J Clin Microbiol. 2011 Jul;49(7):2480-4.
Schechner V, Straus-Robinson K, Schwartz D, Pfeffer I, Tarabeia J, Moskovich R, et al. Evaluation of PCR-based testing for surveillance of KPC-producing carbapenem-resistant members of the Enterobacteriaceae family. J Clin Microbiol. 2009 Oct;47(10):3261-5.
Moran Gilad J, Carmeli Y, Schwartz D, Navon-Venezia S. Laboratory evaluation of the CHROMagar KPC medium for identification of carbapenem-nonsusceptible Enterobacteriaceae. Diagn Microbiol Infect Dis. 2011 Aug;70(4):565-7.
Nordmann P, Girlich D, Poirel L. Detection of carbapenemase producers in Enterobacteriaceae using a novel screening medium. J Clin Microbiol. 2012 Feb 22. 50(8): 2761- 6.
Adler A, Navon-Venezia S, Moran-Gilad J, Marcos E, Schwartz D, Carmeli Y. Laboratory and clinical evaluation of screening agar plates for detection of carbapenem-resistant Enterobacteriaceae from surveillance rectal swabs. J Clin Microbiol. 2011 Jun;49(6):2239-42.
Isenberg HD. Clinical microbiology procedures handbook. 2nd ed. Washington, DC: ASM Press; 2004.
CLSI. Performance standards for antimicrobial susceptibility testing. The Clinical and Laboratory Standards Institute sixteenth informational supplement. . Wayne, PA; 2013.
Poirel L, Pitout JD, Nordmann P. Carbapenemases: molecular diversity and clinical consequences. Future Microbiol. 2007 Oct;2(5):501-12.
Kattan R, Liddawi R, Ghneim R, Siryani I, Al-Dawodi R, Abu-Diab A, et al. Emergence of Klebsiella pneumoniae Carbapenemase (blaKPC-2) in members of the Enterobacteriaceae family in Palestine. The International Arabic Journal Of Antimicrobial Agents. 2012; 2(2:4).
Lolans K, Calvert K, Won S, Clark J, Hayden MK. Direct ertapenem disk screening method for identification of KPC-producing Klebsiella pneumoniae and Escherichia coli in surveillance swab specimens. J Clin Microbiol. 2010 Mar;48(3):836-41.
Percin D, Colakoglu S, Durmaz S, Ekincioglu P. [Comparison of ertapenem-EMB Agar with traditional methods for screening carbapenem-resistant Klebsiella pneumoniae from rectal swabs]. Mikrobiyoloji bulteni. 2012 Oct;46(4):546-52.
Leavitt A, Chmelnitsky I, Colodner R, Ofek I, Carmeli Y, Navon-Venezia S. Ertapenem resistance among extended-spectrum-beta-lactamase-producing Klebsiella pneumoniae isolates. J Clin Microbiol. 2009 Apr;47(4):969-74.
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