Plasmid-Mediated Cephalosporinase ACC-1 in Clinical Isolates of Proteus mirabilis and Escherichia coli

Girlich, Delphine; Karim, A.; Spicq, C.; Nordmann, Patrice

doi:10.1007/s100960000386

Cited by 26 publications

(24 citation statements)

References 9 publications

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“…Based on our previous experience, bands with pIs of 5.2 to 6.5 were suggestive of TEM, those with pIs of 7.0 to 8.2 were suggestive of SHV, and those with pIs of Ն8.3 were suggestive of AmpC-type enzymes (7) (http://www.lahey.org/studies/webt.htm). While it is recognized that the pIs of other ␤-lactamases, such as the CTX-M type (pIs of 7.5 to 8.9) and OXA type (pIs of 5.5 to 9.0), fall within the IEF ranges used in this study, and the pIs of some TEM and AmpC-type enzymes fall outside the ranges (http://www.lahey .org/studies/webt.htm) (5,12,16), the suggested IEF ranges, when used in conjunction with the PCR results, proved to be very effective tools for ESBL characterization.…”

Section: Methodsmentioning

confidence: 89%

Characterization of Clinical Isolates ofKlebsiella pneumoniaefrom 19 Laboratories Using the National Committee for Clinical Laboratory Standards Extended-Spectrum β-Lactamase Detection Methods

et al. 2001

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Extended-spectrum ␤-lactamases (ESBLs) are enzymes found in gram-negative bacilli that mediate resistance to extended-spectrum cephalosporins and aztreonam. In 1999, the National Committee for Clinical Laboratory Standards (NCCLS) published methods for screening and confirming the presence of ESBLs in Klebsiella pneumoniae, Klebsiella oxytoca, and Escherichia coli. To evaluate the confirmation protocol, we tested 139 isolates of K. pneumoniae that were sent to Project ICARE (Intensive Care Antimicrobial Resistance Epidemiology) from 19 hospitals in 11 U.S. states. Each isolate met the NCCLS screening criteria for potential ESBL producers (ceftazidime [CAZ] or cefotaxime [CTX] MICs were >2 g/ml for all isolates). Initially, 117 (84%) isolates demonstrated a clavulanic acid (CA) effect by disk diffusion (i.e., an increase in CAZ or CTX zone diameters of >5 mm in the presence of CA), and 114 (82%) demonstrated a CA effect by broth microdilution (reduction of CAZ or CTX MICs by >3 dilutions). For five isolates, a CA effect could not be determined initially by broth microdilution because of off-scale CAZ results. However, a CA effect was observed in two of these isolates by testing cefepime and cefepime plus CA. The cefoxitin MICs for 23 isolates that failed to show a CA effect by broth microdilution were >32 g/ml, suggesting either the presence of an AmpC-type ␤-lactamase or porin changes that could mask a CA effect. By isoelectric focusing (IEF), 7 of the 23 isolates contained a ␤-lactamase with a pI of >8.3 suggestive of an AmpC-type ␤-lactamase; 6 of the 7 isolates were shown by PCR to contain both ampC-type and bla OXA genes. The IEF profiles of the remaining 16 isolates showed a variety of ␤-lactamase bands, all of which had pIs of <7.5. All 16 isolates were negative by PCR with multiple primer sets for ampC-type, bla OXA , and bla CTX-M genes. In summary, 83.5% of the K. pneumoniae isolates that were identified initially as presumptive ESBL producers were positive for a CA effect, while 5.0% contained ␤-lactamases that likely masked the CA effect. The remaining 11.5% of the isolates studied contained ␤-lactamases that did not demonstrate a CA effect. An algorithm based on phenotypic analyses is suggested for evaluation of such isolates.

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Section: Methodsmentioning

confidence: 89%

Characterization of Clinical Isolates ofKlebsiella pneumoniaefrom 19 Laboratories Using the National Committee for Clinical Laboratory Standards Extended-Spectrum β-Lactamase Detection Methods

et al. 2001

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“…No strains harboring the ACC-1 gene or the chromosomal gene from H. alvei strain 1 (ACC-2 gene) were available. However, the genetic similarity between the ACC-1 gene and the chromosomal genes from H. alvei allowed the use of H. alvei JW3 in this study (12,13). Twenty-two clinical strains belonging to members of the family Enterobacteriaceae phenotypically characterized as putative AmpC producers were evaluated by ampC multiplex PCR for the presence of plasmidmediated ampC genes.…”

Section: Methodsmentioning

confidence: 99%

Detection of Plasmid-Mediated AmpC β-Lactamase Genes in Clinical Isolates by Using Multiplex PCR

2002

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Therapeutic options for infections caused by gram-negative organisms expressing plasmid-mediated AmpC ␤-lactamases are limited because these organisms are usually resistant to all the ␤-lactam antibiotics, except for cefepime, cefpirome, and the carbapenems. These organisms are a major concern in nosocomial infections and should therefore be monitored in surveillance studies. Six families of plasmid-mediated AmpC ␤-lactamases have been identified, but no phenotypic test can differentiate among them, a fact which creates problems for surveillance and epidemiology studies. This report describes the development of a multiplex PCR for the purpose of identifying family-specific AmpC ␤-lactamase genes within gram-negative pathogens. The PCR uses six sets of ampC-specific primers resulting in amplicons that range from 190 bp to 520 bp and that are easily distinguished by gel electrophoresis. ampC multiplex PCR differentiated the six plasmid-mediated ampCspecific families in organisms such as Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, and Salmonella enterica serovar Typhimurium. Family-specific primers did not amplify genes from the other families of ampC genes. Furthermore, this PCR-based assay differentiated multiple genes within one reaction. In addition, WAVE technology, a high-pressure liquid chromatography-based separation system, was used as a way of decreasing analysis time and increasing the sensitivity of multiple-gene assays. In conclusion, a multiplex PCR technique was developed for identifying family-specific ampC genes responsible for AmpC ␤-lactamase expression in organisms with or without a chromosomal AmpC ␤-lactamase gene.

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“…pneumoniae strains producing plasmid-mediated AmpC ␤-lactamases such as MIR-1 (15), ACT-1 (4), and more recently ACC-1 (14) have been implicated in numerous nosocomial outbreaks (16). AmpC ACC-1 is a plasmid-encoded class C ␤-lactamase originating from Hafnia alvei and now found in various members of the family Enterobacteriaceae in North Africa and Europe (2,7,8,11,13,14,18). Combination of a plasmid-mediated AmpC ␤-lactamase and loss of an outer membrane protein can lead to imipenem resistance in K. pneumoniae (4,5); the two incriminated enzymes were ACT-1 and CMY-4, which are closely related to their chromosomal counterparts in Enterobacter cloacae and Citrobacter freundii, respectively (16).…”

mentioning

confidence: 99%

In Vivo Transfer of Plasmid-Encoded ACC-1 AmpC from Klebsiella pneumoniae to Escherichia coli in an Infant and Selection of Impermeability to Imipenem in K. pneumoniae

Bidet

Burghoffer

Gautier

et al. 2005

Antimicrob Agents Chemother

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We describe in vivo selection of a Klebsiella pneumoniae strain with diminished imipenem susceptibility attributable to plasmid-encoded ACC-1 ␤-lactamase production and loss of a 36-kDa major outer membrane protein, together with transfer of this plasmid from K. pneumoniae to Escherichia coli in a Tunisian infant.Resistance to carbapenems in gram-negative bacteria may be due either to carbapenemase production or to combination of chromosomal or plasmid-mediated class C ␤-lactamase overproduction and impermeability (20). Among plasmid-mediated AmpC proteins, only ACT-1 and CMY-2 types have been reported to confer resistance to imipenem in association with porin loss (4,5,12).We isolated a Klebsiella pneumoniae strain with diminished imipenem susceptibility from a Tunisian infant. This resistance was related to a combination of plasmid-mediated AmpC ACC-1 expression and impermeability acquired under antimicrobial pressure.A 1-year-old boy from Tunisia with spina bifida and cloacal extrophy was admitted to Robert-Debré hospital (Paris, France) for reconstruction, enterocystoplasty (Mitrofanoff procedure), and pelvic osteotomy. Surgery was complicated by suppuration and disunion of the pubic symphysis. Pus culture yielded ampicillin-resistant Escherichia coli and ceftazidimeresistant Pseudomonas aeruginosa. Imipenem and amikacin were given for 20 days postoperatively. Before surgery, fecal analysis showed carriage of a cefotaxime-resistant, imipenemsusceptible K. pneumoniae strain (isolate K1, 10 5 CFU/g). At the end of antibacterial chemotherapy (postoperative day 20), the ileal flora grew a cefotaxime-resistant K. pneumoniae strain with diminished imipenem sensitivity (isolate K2, 10 5 CFU/g). The child subsequently developed two urinary tract infections due to an ampicillin-resistant E. coli strain (isolate E1), on postoperative days 30 and day 45, both episodes being treated with cefotaxime and gentamicin. A third culture of the enteric flora on day 45 grew both a cefotaxime-resistant E. coli strain (isolate E2, 10 8 CFU/g) and the previous K. pneumoniae isolate, K2 (10 5 CFU/g). K. pneumoniae and E. coli were identified using commercial kits (API 20E and ID32GN; Biomerieux, Marcy l'Etoile, France). Antimicrobial susceptibility was tested by the disk diffusion method on Mueller-Hinton agar (Sanofi-Diagnostics Pasteur, Marnes-La-Coquette, France), as recommended by the Clinical and Laboratory Standards Institute. The MICs of amoxicillin, cefoxitin, cefotaxime, ceftazidime, cefepime, and imipenem were determined by the E-test method (Biodisk, Solna, Sweden). The imipenem and cefepime MICs were also determined by the E-test method on Mueller-Hinton agar containing 250 g/ml cloxacillin (17).Resistance transfer experiments from E. coli E1 and K. pneumoniae K1 and K2 were performed by conjugation with E. coli J53-2 as previously described (1). The MICs of selected ␤-lactam antibiotics and associated resistance markers for the clinical isolates and transconjugants are shown in Table 1.Clinical isolates E2, K1, and K2 w...

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Plasmid-Mediated Cephalosporinase ACC-1 in Clinical Isolates of Proteus mirabilis and Escherichia coli

Cited by 26 publications

References 9 publications

Characterization of Clinical Isolates ofKlebsiella pneumoniaefrom 19 Laboratories Using the National Committee for Clinical Laboratory Standards Extended-Spectrum β-Lactamase Detection Methods

Characterization of Clinical Isolates ofKlebsiella pneumoniaefrom 19 Laboratories Using the National Committee for Clinical Laboratory Standards Extended-Spectrum β-Lactamase Detection Methods

Detection of Plasmid-Mediated AmpC β-Lactamase Genes in Clinical Isolates by Using Multiplex PCR

In Vivo Transfer of Plasmid-Encoded ACC-1 AmpC from Klebsiella pneumoniae to Escherichia coli in an Infant and Selection of Impermeability to Imipenem in K. pneumoniae

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