scholarly journals Rapid and Accurate Detection of Escherichia coli and Klebsiella pneumoniae Strains Susceptible/Resistant to Cotrimoxazole through Evaluation of Cell Elongation

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 720
Author(s):  
Isidoro López ◽  
Fátima Otero ◽  
Rebeca Guillén ◽  
María del Carmen Fernández ◽  
Germán Bou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Folic Acid ◽  
Klebsiella Pneumoniae ◽  
Broad Spectrum ◽  
Cell Elongation ◽  
Acid Synthesis ◽  
Cell Enlargement ◽  
False Negatives ◽  
Resistant Strains ◽  
Selection Of

Trimethoprim-sulfamethoxazole is a well-known antibiotic that inhibits folic acid synthesis, a topic of renewed interest. Since resistant strains are increasingly more common, an early and accurate discrimination of susceptibility may assure confident therapy. Two morphological assays were performed in Escherichia coli (n = 50; 27 non-susceptible) and Klebsiella pneumoniae (n = 52; 18 non-susceptible). First, the strains were incubated with the CLSI breakpoint of cotrimoxazole for 150 min, which induced cell lengthening in the susceptible strains. Second, the bacteria were incubated with mitomycin C (MMC) (0.5 mg/L) for 120 min to induce a SOS-linked cell enlargement higher than that obtained by cotrimoxazole alone. When cotrimoxazole was added 30 min before MMC, the inhibition of folic acid synthesis in the susceptible strain resulted in the suppression of MMC-induced extra elongation. In the non-susceptible strains, folic acid synthesis continued despite the antibiotic, so that the MMC-induced extra cell lengthening could not be impeded. Whereas the first assay resulted in five false negatives and four false positives of resistance, the results of the second assay matched those of the conventional antibiogram. This simple morphological procedure is performed in 2 h and 45 min and may allow a rapid selection of useful and relatively inexpensive therapy, thereby preserving the newer broad-spectrum antibiotics.

scholarly journals Effect of Dimethyl Sulphoxide on the Expression of Nitrogen Fixation in Bacteria

1977 ◽  
Vol 30 (2) ◽  
pp. 141 ◽  
Author(s):  
Mary L Skotnicki ◽  
Barry G Rolfe
Keyword(s):  
Escherichia Coli ◽  
Nitrogen Fixation ◽  
Energy Metabolism ◽  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Dimethyl Sulphoxide ◽  
Rhizobium Trifolii ◽  
Nif Genes ◽  
E Coli ◽  
Selection Of

Storage in dimethyl sulphoxide (DMSO) of Escherichia coli K12 hybrids carrying nif+ genes from Klebsiella pneumoniae can result in selection of a defective nitrogen-fixing phenotype. Similar results are obtained with E. coli K12 hybrids containing the nitrogep-fixing capacity from Rhizobium trifolii. DMSO appears to affect particular inner membrane proteins associated with energy metabolism in E. coli K12 and four chromosomal regions (chID, chlG, his and unc) are associated with resistance to DMSO.

scholarly journals In Vitro Activity of a Novel Siderophore-Cephalosporin, GT-1 and Serine-Type β-Lactamase Inhibitor, GT-055, against Escherichia coli, Klebsiella pneumoniae and Acinetobacter spp. Panel Strains

Antibiotics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 267 ◽  
Author(s):  
Le Phuong Nguyen ◽  
Naina Adren Pinto ◽  
Thao Nguyen Vu ◽  
Hyunsook Lee ◽  
Young Lag Cho ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Vitro Activity ◽  
Intrinsic Activity ◽  
In Vitro Activity ◽  
E Coli ◽  
Acinetobacter Spp ◽  
Resistant Strains ◽  
Lactamase Inhibitor

This study investigates GT-1 (also known as LCB10-0200), a novel-siderophore cephalosporin, inhibited multidrug-resistant (MDR) Gram-negative pathogen, via a Trojan horse strategy exploiting iron-uptake systems. We investigated GT-1 activity and the role of siderophore uptake systems, and the combination of GT-1 and a non-β-lactam β-lactamase inhibitor (BLI) of diazabicyclooctane, GT-055, (also referred to as LCB18-055) against molecularly characterised resistant Escherichia coli, Klebsiella pneumoniae and Acinetobacter spp. isolates. GT-1 and GT-1/GT-055 were tested in vitro against comparators among three different characterised panel strain sets. Bacterial resistome and siderophore uptake systems were characterised to elucidate the genetic basis for GT-1 minimum inhibitory concentrations (MICs). GT-1 exhibited in vitro activity (≤2 μg/mL MICs) against many MDR isolates, including extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing E. coli and K. pneumoniae and oxacillinase (OXA)-producing Acinetobacter spp. GT-1 also inhibited strains with mutated siderophore transporters and porins. Although BLI GT-055 exhibited intrinsic activity (MIC 2–8 μg/mL) against most E. coli and K. pneumoniae isolates, GT-055 enhanced the activity of GT-1 against many GT-1–resistant strains. Compared with CAZ-AVI, GT-1/GT-055 exhibited lower MICs against E. coli and K. pneumoniae isolates. GT-1 demonstrated potent in vitro activity against clinical panel strains of E. coli, K. pneumoniae and Acinetobacter spp. GT-055 enhanced the in vitro activity of GT-1 against many GT-1–resistant strains.

CHARACTERIZATION OF KLEBSIELLA PNEUMONIAE AND ESCHERICHIA COLI STRAINS THAT PRODUCE CTX-M-2-TYPE BROAD SPECTRUM BETA-LACTAMASE ISOLATED FROM A CHILD WITH LEUKEMIA

2002 ◽  
Vol 21 (3) ◽  
pp. 260-262 ◽  
Author(s):  
Toshiya Ohkawa ◽  
Masao Yoshinaga ◽  
Naoaki Ikarimoto ◽  
Hiroaki Miyanohara ◽  
Koichiro Miyata ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Broad Spectrum ◽  
Beta Lactamase

scholarly journals 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

2005 ◽  
Vol 49 (8) ◽  
pp. 3562-3565 ◽  
Author(s):  
Philippe Bidet ◽  
Béatrice Burghoffer ◽  
Valérie Gautier ◽  
Naïma Brahimi ◽  
Patricia Mariani-Kurkdjian ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Major Outer Membrane Protein ◽  
In Vivo Selection ◽  
Selection Of

ABSTRACT We describe in vivo selection of a Klebsiella pneumoniae strain with diminished imipenem susceptibility attributable to plasmid-encoded ACC-1 β-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.

scholarly journals In Vitro Activities of the Potent, Broad-Spectrum Carbapenem MK-0826 (L-749,345) against Broad-Spectrum β-Lactamase-and Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae and Escherichia coli Clinical Isolates

1999 ◽  
Vol 43 (5) ◽  
pp. 1170-1176 ◽  
Author(s):  
Joyce Kohler ◽  
Karen L. Dorso ◽  
Katherine Young ◽  
Gail G. Hammond ◽  
Hugh Rosen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Broad Spectrum ◽  
Bacterial Resistance ◽  
Clinical Isolates ◽  
Inoculum Level ◽  
E Coli ◽  
Extended Spectrum ◽  
Group 1

ABSTRACT An important mechanism of bacterial resistance to β-lactam antibiotics is inactivation by β-lactam-hydrolyzing enzymes (β-lactamases). The evolution of the extended-spectrum β-lactamases (ESBLs) is associated with extensive use of β-lactam antibiotics, particularly cephalosporins, and is a serious threat to therapeutic efficacy. ESBLs and broad-spectrum β-lactamases (BDSBLs) are plasmid-mediated class A enzymes produced by gram-negative pathogens, principallyEscherichia coli and Klebsiella pneumoniae. MK-0826 was highly potent against all ESBL- and BDSBL-producingK. pneumoniae and E. coli clinical isolates tested (MIC range, 0.008 to 0.12 μg/ml). In E. coli, this activity was associated with high-affinity binding to penicillin-binding proteins 2 and 3. When the inoculum level was increased 10-fold, increasing the amount of β-lactamase present, the MK-0826 MIC range increased to 0.008 to 1 μg/ml. By comparison, similar observations were made with meropenem while imipenem MICs were usually less affected. Not surprisingly, MIC increases with noncarbapenem β-lactams were generally substantially greater, resulting in resistance in many cases. E. coli strains that produce chromosomal (Bush group 1) β-lactamase served as controls. All three carbapenems were subject to an inoculum effect with the majority of the BDSBL- and ESBL-producers but not the Bush group 1 strains, implying some effect of the plasmid-borne enzymes on potency. Importantly, MK-0826 MICs remained at or below 1 μg/ml under all test conditions.

scholarly journals Distribution of Extended-Spectrum β-Lactamases in Clinical Isolates of Enterobacteriaceae in Vietnam

2002 ◽  
Vol 46 (12) ◽  
pp. 3739-3743 ◽  
Author(s):  
Van Cao ◽  
Thierry Lambert ◽  
Duong Quynh Nhu ◽  
Huynh Kim Loan ◽  
Nguyen Kim Hoang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Broad Spectrum ◽  
Molecular Typing ◽  
Ho Chi Minh City ◽  
Structural Genes ◽  
E Coli ◽  
Extended Spectrum ◽  
Pcr Products ◽  
M 14

ABSTRACT Among 730 Escherichia coli, 438 Klebsiella pneumoniae, and 141 Proteus mirabilis isolates obtained between September 2000 and September 2001 in seven hospitals in Ho Chi Minh City, Vietnam, 26.6% were resistant to ceftazidime, 30% were resistant to cefotaxime, 31.5% were resistant to ceftriaxone, 15.9% were resistant to cefoperazone, and 6% were resistant to cefepime. Resistance to imipenem was found in 5.6% of the isolates. In 55 strains producing extended-spectrum β-lactamases (32 E. coli isolates, 13 K. pneumoniae isolates, and 10 P. mirabilis isolates), structural genes for VEB-1 (25.5%), CTX-M (25.5%), SHV (38.1%), and TEM (76.3%) enzymes were detected alone or in combination. Sequencing of the PCR products obtained from the K. pneumoniae isolates revealed the presence of bla VEB-1, bla CTX-M-14, bla CTX-M-17, bla SHV-2, and bla TEM-1. Molecular typing of the strains with a similar resistance phenotype to broad-spectrum cephalosporins indicated polyclonal spread. ISEcp1 was presumably responsible for dissemination of the bla CTX-M-like gene.

scholarly journals CTX-M Expression and Selection of Ertapenem Resistance in Klebsiella pneumoniae and Escherichia coli

2008 ◽  
Vol 53 (2) ◽  
pp. 832-834 ◽  
Author(s):  
Delphine Girlich ◽  
Laurent Poirel ◽  
Patrice Nordmann
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
In Vitro Selection ◽  
Gene Frequencies ◽  
Clinical Strains ◽  
Selection Of

ABSTRACT In vitro selection of mutants with decreased susceptibility to ertapenem was performed using Escherichia coli and Klebsiella pneumoniae clinical strains producing either the bla CTX-M-2, bla CTX-M-3, bla CTX-M-9, or bla CTX-M-15 gene. Frequencies of mutants with decreased susceptibilities to ertapenem were similar for all β-lactamases expressed.

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