scholarly journals Occurrence of Efflux Mechanism and Cephalosporinase Variant in a Population of Enterobacter aerogenes and Klebsiella pneumoniae Isolates Producing Extended-Spectrum β-Lactamases

2009 ◽  
Vol 53 (4) ◽  
pp. 1652-1656 ◽  
Author(s):  
Que-Tien Tran ◽  
Myrielle Dupont ◽  
Jean-Philippe Lavigne ◽  
Jacqueline Chevalier ◽  
Jean-Marie Pagès ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Klebsiella Pneumoniae ◽  
Enterobacter Aerogenes ◽  
Clinical Isolates ◽  
Active Efflux ◽  
Specific Mutation ◽  
Extended Spectrum ◽  
Efflux Mechanism

ABSTRACT We investigated the occurrence of multidrug resistance in 44 Enterobacter aerogenes and Klebsiella pneumoniae clinical isolates. Efflux was involved in resistance in E. aerogenes isolates more frequently than in K. pneumoniae isolates (100 versus 38% of isolates) and was associated with the expression of phenylalanine arginine β-naphthylamide-susceptible active efflux. AcrA-TolC overproduction in E. aerogenes isolates was noted. An analysis of four E. aerogenes isolates for which cefepime MICs were high revealed no modification in porin expression but a new specific mutation in the AmpC β-lactamase.

scholarly journals Comparative Genomics of Klebsiella pneumoniae Strains with Different Antibiotic Resistance Profiles

2011 ◽  
Vol 55 (9) ◽  
pp. 4267-4276 ◽  
Author(s):  
Vinod Kumar ◽  
Peng Sun ◽  
Jessica Vamathevan ◽  
Yong Li ◽  
Karen Ingraham ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Susceptible Strain ◽  
Clinical Isolates ◽  
Whole Genome ◽  
Content Type ◽  
Extended Spectrum

ABSTRACTThere is a global emergence of multidrug-resistant (MDR) strains ofKlebsiella pneumoniae, a Gram-negative enteric bacterium that causes nosocomial and urinary tract infections. While the epidemiology ofK. pneumoniaestrains and occurrences of specific antibiotic resistance genes, such as plasmid-borne extended-spectrum β-lactamases (ESBLs), have been extensively studied, only four complete genomes ofK. pneumoniaeare available. To better understand the multidrug resistance factors inK. pneumoniae, we determined by pyrosequencing the nearly complete genome DNA sequences of two strains with disparate antibiotic resistance profiles, broadly drug-susceptible strain JH1 and strain 1162281, which is resistant to multiple clinically used antibiotics, including extended-spectrum β-lactams, fluoroquinolones, aminoglycosides, trimethoprim, and sulfamethoxazoles. Comparative genomic analysis of JH1, 1162281, and other publishedK. pneumoniaegenomes revealed a core set of 3,631 conserved orthologous proteins, which were used for reconstruction of whole-genome phylogenetic trees. The close evolutionary relationship between JH1 and 1162281 relative to otherK. pneumoniaestrains suggests that a large component of the genetic and phenotypic diversity of clinical isolates is due to horizontal gene transfer. Using curated lists of over 400 antibiotic resistance genes, we identified all of the elements that differentiated the antibiotic profile of MDR strain 1162281 from that of susceptible strain JH1, such as the presence of additional efflux pumps, ESBLs, and multiple mechanisms of fluoroquinolone resistance. Our study adds new and significant DNA sequence data onK. pneumoniaestrains and demonstrates the value of whole-genome sequencing in characterizing multidrug resistance in clinical isolates.

scholarly journals Energy-Dependent Accumulation of Norfloxacin and Porin Expression in Clinical Isolates of Klebsiella pneumoniae and Relationship to Extended-Spectrum β-Lactamase Production

2002 ◽  
Vol 46 (12) ◽  
pp. 3926-3932 ◽  
Author(s):  
Luis Martínez-Martínez ◽  
Alvaro Pascual ◽  
María del Carmen Conejo ◽  
Isabel García ◽  
Providencia Joyanes ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Quinolone Resistance ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Esbl Production ◽  
Active Efflux ◽  
Extended Spectrum ◽  
Carbonyl Cyanide ◽  
Energy Dependent

ABSTRACT The relationships between porin deficiency, active efflux of fluoroquinolones, and extended-spectrum β-lactamase (ESBL) production were determined for 53 clinical isolates of Klebsiella pneumoniae. Thirty-two ESBL-positive strains (including 22 strains expressing porins and 10 strains lacking porins) and 21 ESBL-negative strains were evaluated. Active efflux of norfloxacin was defined as a ≥50% increase in the accumulation of norfloxacin in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) in comparison with the corresponding basal value in the absence of CCCP. The quinolone resistance-determining regions of both gyrA and parC from 13 strains, representing all isolates with different porin profiles and with or without active efflux, were determined. Porin loss was significantly more common among ESBL-positive strains (10 of 32 [31.2%]) than among ESBL-negative strains (0 of 2 [0%]) (P < 0.01). Active efflux was observed in 7 of 10 (70%) strains lacking porins and in 4 of 43 (9.3%) strains producing porins (P < 0.001). The 11 strains showing active efflux corresponded to 3 of 21 (14.3%) ESBL-negative strains and 8 of 32 (25.5%) ESBL-positive strains (P > 0.05). Basal values of norfloxacin accumulation were higher in strains lacking active efflux than in those that had this mechanism (P < 0.05). In the absence of topoisomerase changes, the contribution of either porin loss or active efflux to fluoroquinolone resistance in K. pneumoniae was negligible. It is concluded that among K. pneumoniae strains of clinical origin, porin loss was observed only in those producing ESBL, and that a significant number of porin-deficient strains also expressed active efflux of norfloxacin. In terms of fluoroquinolone resistance, both mechanisms are significant only in the presence of topoisomerase modifications.

scholarly journals TEM Derivative-Producing Enterobacter aerogenes Strains: Dissemination of a Prevalent Clone

2002 ◽  
Vol 46 (4) ◽  
pp. 1128-1131 ◽  
Author(s):  
P. Dumarche ◽  
C. De Champs ◽  
D. Sirot ◽  
C. Chanal ◽  
R. Bonnet ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Enterobacter Aerogenes ◽  
Clonal Strain ◽  
Extended Spectrum ◽  
Strain Dependent

ABSTRACT TEM-24 (CAZ-6) extended-spectrum β-lactamase (ESBL) was detected in 1988 in Clermont-Ferrand, France, in Klebsiella pneumoniae (bla TEM-24) and Enterobacter aerogenes (bla TEM-24b), and since 1994, a TEM-24-producing E. aerogenes clonal strain has been observed elsewhere in the country. To determine if the spread of this clonal strain was restricted to TEM-24-producing E. aerogenes strains, 84 E. aerogenes strains (non-TEM/SHV-producing strains, TEM-1- or -2-producing strains, and different ESBL-producing strains), isolated from 1988 to 1999 in Clermont-Ferrand (n = 59) and in 11 other French hospitals in 1998 (n = 25), were studied. A clonal strain was found for TEM-24- but also for TEM-3- and TEM-1- or 2-producing isolates. This study shows that there is a clonal strain dependent on acquisition of the TEM-type enzyme (TEM-24 and other TEM types).

scholarly journals Nationwide Study of the Prevalence, Characteristics, and Molecular Epidemiology of Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae in France

2007 ◽  
Vol 52 (2) ◽  
pp. 786-789 ◽  
Author(s):  
Muriel Galas ◽  
Jean-Winoc Decousser ◽  
Nelly Breton ◽  
Thierry Godard ◽  
Pierre Yves Allouch ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Molecular Epidemiology ◽  
Molecular Analysis ◽  
Enterobacter Aerogenes ◽  
Nationwide Study ◽  
E Coli ◽  
Extended Spectrum ◽  
Prevalent Species

ABSTRACT Among 10,872 isolates of Enterobacteriaceae from a nationwide study of 88 French hospitals in 2005, 169 (1.7%) expressed an extended-spectrum β-lactamase. The most prevalent species were Escherichia coli (48.5%), Enterobacter aerogenes (23.7%), and Klebsiella pneumoniae (14.8%). Molecular analysis underlined the polyclonal spread of CTX-M-expressing E. coli, primarily isolates of the CTX-M-1 subgroup.

scholarly journals Inhibitors of Antibiotic Efflux in Resistant Enterobacter aerogenes and Klebsiella pneumoniae Strains

2004 ◽  
Vol 48 (3) ◽  
pp. 1043-1046 ◽  
Author(s):  
Jacqueline Chevalier ◽  
Jérôme Bredin ◽  
Abdallah Mahamoud ◽  
Monique Malléa ◽  
Jacques Barbe ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Klebsiella Pneumoniae ◽  
Efflux Pump ◽  
Enterobacter Aerogenes ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Resistance Phenotype ◽  
Pump Mechanism ◽  
Energy Dependent ◽  
Antibiotic Efflux

ABSTRACT In Enterobacter aerogenes and Klebsiella pneumoniae, efflux provides efficient extrusion of antibiotics and contributes to the multidrug resistance phenotype. One of the alkoxyquinoline derivatives studied here, 2,8-dimethyl-4-(2′-pyrrolidinoethyl)-oxyquinoline, restores noticeable drug susceptibility to resistant clinical strains. Analyses of energy-dependent chloramphenicol efflux indicate that this compound inhibits the efflux pump mechanism and improves the activity of structurally unrelated antibiotics on multidrug-resistant E. aerogenes and K. pneumoniae isolates.

scholarly journals Survey of Extended-Spectrum β-Lactamases in Clinical Isolates of Escherichia coli and Klebsiella pneumoniae: Prevalence of TEM-52 in Korea

1999 ◽  
Vol 37 (6) ◽  
pp. 1758-1763 ◽  
Author(s):  
Hyunjoo Pai ◽  
Sen Lyu ◽  
Ji Hyang Lee ◽  
Jungmin Kim ◽  
Youngmi Kwon ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Genetic Relatedness ◽  
Clinical Isolates ◽  
E Coli ◽  
Extended Spectrum ◽  
High Prevalence

Two hundred ninety isolates of Escherichia coli were investigated for the production of extended-spectrum β-lactamases (ESBLs). Fourteen (4.8%) of the 290 strains were found to produce ESBLs. Each of the 14 strains produced one or two ESBLs, as follows: 10 strains produced TEM-52, 1 strain produced SHV-2a, 1 strain produced SHV-12, 1 strain produced a CMY-1-like enzyme, and 1 strain expressed SHV-2a and a CMY-1-like enzyme. Another two strains for which the MICs of ceftazidime and cefoxitin were high, were probable AmpC enzyme hyperproducers. Because of the high prevalence of TEM-52 in E. coli isolates, we further investigated the TEM-type ESBLs produced by Klebsiella pneumoniae in order to observe the distribution of TEM-52 enzymes among Enterobacteriaceae in Korea. All TEM enzymes produced by 12 strains of K. pneumoniae were identified as TEM-52. To evaluate the genetic relatedness among the organisms, ribotyping of TEM-52-producingE. coli and K. pneumoniae was performed. The ribotyping profiles of the organisms showed similar but clearly different patterns. In conclusion, TEM-52 is the most prevalent TEM-type ESBL in Korea.

Sign in / Sign up

Export Citation Format

Share Document