First clinical isolate of Streptococcus pneumoniae exhibiting high-level resistance to fluoroquinolones in Taiwan

2001 ◽  
Vol 48 (2) ◽  
pp. 316-317 ◽  
Author(s):  
P.-R. Hsueh
Keyword(s):  
Streptococcus Pneumoniae ◽  
Clinical Isolate ◽  
High Level ◽  
Level Resistance

scholarly journals Diversity of Substitutions within or Adjacent to Conserved Amino Acid Motifs of Penicillin-Binding Protein 2X in Cephalosporin-Resistant Streptococcus pneumoniaeIsolates

1999 ◽  
Vol 43 (5) ◽  
pp. 1252-1255 ◽  
Author(s):  
Yasuko Asahi ◽  
Yasuo Takeuchi ◽  
Kimiko Ubukata
Keyword(s):  
Streptococcus Pneumoniae ◽  
Amino Acid ◽  
Three Dimensional ◽  
Crystallographic Structure ◽  
Amino Acid Substitutions ◽  
Penicillin Binding Protein ◽  
Amino Acid Motif ◽  
Dna Fragment ◽  
High Level ◽  
Level Resistance

ABSTRACT The sequence of an approximately 1.1-kb DNA fragment of thepbp2x gene, which encodes the transpeptidase domain, was determined for 35 clinical isolates of Streptococcus pneumoniae for which the cefotaxime (CTX) MICs varied. Strains with substitutions within a conserved amino acid motif changing STMK to SAFK and a Leu-to-Val change just before the KSG motif were highly resistant to CTX (MIC, ≧2 μg/ml). Strains with substitutions adjacent to SSN or KSG motifs had low-level resistance. The amino acid substitutions were plotted on the three-dimensional crystallographic structure of the transpeptidase domain of PBP2X. Transformants containing pbp2x from strains with high-level CTX resistance increased the CTX MIC from 0.016 μg/ml to 0.5 to 1.0 μg/ml.

scholarly journals Extended-Spectrum Cephalosporinase in Acinetobacter baumannii

2010 ◽  
Vol 54 (8) ◽  
pp. 3484-3488 ◽  
Author(s):  
José-Manuel Rodríguez-Martínez ◽  
Patrice Nordmann ◽  
Esthel Ronco ◽  
Laurent Poirel
Keyword(s):  
Acinetobacter Baumannii ◽  
Clinical Isolate ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Extended Spectrum ◽  
Class C ◽  
High Level ◽  
Level Resistance

ABSTRACT An AmpC-type β-lactamase conferring high-level resistance to expanded-spectrum cephalosporins and monobactams was characterized from an Acinetobacter baumannii clinical isolate. This class C β-lactamase (named ADC-33) possessed a Pro210Arg substitution together with a duplication of an Ala residue at position 215 (inside the Ω-loop) compared to a reference AmpC cephalosporinase from A. baumannii. ADC-33 hydrolyzed ceftazidime, cefepime, and aztreonam at high levels, which allows the classification of this enzyme as an extended-spectrum AmpC (ESAC). Site-directed mutagenesis confirmed the role of both substitutions in its ESAC property.

scholarly journals Association of two resistance mechanisms in a clinical isolate of Enterobacter cloacae with high-level resistance to imipenem.

1991 ◽  
Vol 35 (6) ◽  
pp. 1093-1098 ◽  
Author(s):  
E H Lee ◽  
M H Nicolas ◽  
M D Kitzis ◽  
G Pialoux ◽  
E Collatz ◽  
...  
Keyword(s):  
Clinical Isolate ◽  
Enterobacter Cloacae ◽  
Resistance Mechanisms ◽  
High Level ◽  
Level Resistance

scholarly journals Genetic Characterization of Fluoroquinolone-Resistant Streptococcus pneumoniae Strains Isolated during Ciprofloxacin Therapy from a Patient with Bronchiectasis

2003 ◽  
Vol 47 (4) ◽  
pp. 1419-1422 ◽  
Author(s):  
Adela G. de la Campa ◽  
María-José Ferrandiz ◽  
Fe Tubau ◽  
Román Pallarés ◽  
Federico Manresa ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Characterization ◽  
Susceptible Strain ◽  
Low Level ◽  
Resistant Strains ◽  
Resistant Mutants ◽  
High Level ◽  
Level Resistance

ABSTRACT Five Spain9V-3 Streptococcus pneumoniae strains were isolated from a patient with bronchiectasis who had received long-term ciprofloxacin therapy. One ciprofloxacin-susceptible strain was isolated before treatment, and four ciprofloxacin-resistant strains were isolated during treatment. The resistant strains were derived from the susceptible strain either by a parC mutation (low-level resistance) or by parC and gyrA mutations (high-level resistance). This study shows that ciprofloxacin therapy in a patient colonized by susceptible S. pneumoniae may select fluoroquinolone-resistant mutants.

scholarly journals A pneumococcal clinical isolate with high-level resistance to cefotaxime and ceftriaxone.

1992 ◽  
Vol 36 (4) ◽  
pp. 886-889 ◽  
Author(s):  
A M Figueiredo ◽  
J D Connor ◽  
A Severin ◽  
M V Vaz Pato ◽  
A Tomasz
Keyword(s):  
Clinical Isolate ◽  
High Level ◽  
Level Resistance

scholarly journals Emergence in France of Multiple Clones of ClinicalStreptococcus pneumoniae Isolates with High-Level Resistance to Amoxicillin

1999 ◽  
Vol 43 (6) ◽  
pp. 1480-1483 ◽  
Author(s):  
Catherine Doit ◽  
Chawki Loukil ◽  
Frederic Fitoussi ◽  
Pierre Geslin ◽  
Edouard Bingen
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Relatedness ◽  
Molecular Fingerprinting ◽  
High Level ◽  
Level Resistance

ABSTRACT The genetic relatedness of French isolates of Streptococcus pneumoniae highly resistant to amoxicillin (MIC, ≥4 μg/ml, equal to or exceeding those of penicillin) was investigated by molecular fingerprinting. The results suggest that high-level resistance to amoxicillin has emerged within preexisting penicillin-resistant clones.

scholarly journals Low-Level Resistance to Rifampin in Streptococcus pneumoniae

2003 ◽  
Vol 47 (3) ◽  
pp. 863-868 ◽  
Author(s):  
Patricia Stutzmann Meier ◽  
Silvia Utz ◽  
Suzanne Aebi ◽  
Kathrin Mühlemann
Keyword(s):  
Streptococcus Pneumoniae ◽  
Point Mutations ◽  
Low Level ◽  
Development Of Resistance ◽  
Rifampin Resistance ◽  
High Level ◽  
Tissue Compartments ◽  
Level Resistance

ABSTRACT Rifampin is recommended for combination therapy of meningitis due to β-lactam-resistant Streptococcus pneumoniae. High-level rifampin resistance (MIC, ≥4 mg/liter) has been mapped to point mutations in clusters I and III of rpoB of the pneumococcus. The molecular basis of low-level resistance (MICs, ≥0.5 and <4 mg/liter) was analyzed. Spontaneous mutants of clinical pneumococcal isolates were selected on Columbia sheep blood agar plates containing rifampin at 0.5, 4, 10, or 50 mg/liter. Low-level resistance could be assigned to mutations in cluster II (I545N, I545L). Sensitive (MIC, <0.048 mg/liter) wild-type strains acquired low-level resistance at a rate approximately 10 times higher than that at which they acquired high-level resistance (average mutation frequencies, 2.4 × 10−7 for low-level resistance versus 2.9 × 10−8 for high-level resistance [P < 0.0001]). In second-step experiments, the frequencies of mutations from low- to high-level resistance were over 10 times higher than the frequencies of mutations from susceptibility to high-level resistance (average mutation frequencies, 7.2 × 10−7 versus 5.0 × 10−8 [P < 0.001]). Mutants with low-level resistance were stable upon passage. Sequencing of a clinical isolate with low-level resistance (MIC, 0.5 mg/liter) revealed a Q150R mutation upstream of cluster I. The frequencies of mutations to high-level resistance for this strain were even higher than the rates observed for the in vitro mutants. Therefore, a resistance-mediating mutation located outside clusters I, II, and III has been described for the first time in the pneumococcus. In vitro low-level rifampin resistance in S. pneumoniae could be mapped to cluster II of rpoB. Mutants of pneumococcus with low-level resistance may be selected in vivo during therapy in tissue compartments with low antibiotic concentrations and play a role in the development of resistance.

scholarly journals Characterization of an Enterococcus gallinarum Isolate Carrying a DualvanAandvanBCassette

2015 ◽  
Vol 53 (7) ◽  
pp. 2225-2229 ◽  
Author(s):  
Alireza Eshaghi ◽  
Dea Shahinas ◽  
Aimin Li ◽  
Ruwandi Kariyawasam ◽  
Philip Banh ◽  
...  
Keyword(s):  
Clinical Isolate ◽  
Resistance Mechanism ◽  
Vancomycin Resistance ◽  
Content Type ◽  
Enterococcal Species ◽  
Enterococcus Gallinarum ◽  
High Level ◽  
Identification And Characterization ◽  
Level Resistance

The ability of vancomycin resistance determinants to be horizontally transferred within enterococci species is a concern. Identification and characterization of vancomycin-resistant enterococci (VRE) in a clinical isolate have a significant impact on infection control practices. In this study, we describe a clinical isolate ofEnterococcus gallinarumexhibiting high-level resistance to vancomycin and teicoplanin. The genetic characterization of this isolate showed the presence ofvanAandvanBgenes in addition to the naturally carriedvanCgene.vanAwas identified on pA6981, a 35,608-bp circular plasmid with significant homology to plasmid pS177. ThevanBoperon was integrated into the bacterial chromosome and showed a high level of homology to previously reported Tn1549and Tn5382. To the best of our knowledge, this is the first report ofE. gallinarumcarrying bothvanAandvanBoperons, indicating the importance of identifying the vancomycin resistance mechanism in non-E. faeciumand non-E. faecalisenterococcal species.

Canadian national survey of prevalence of antimicrobial resistance among clinical isolates of Streptococcus pneumoniae. Canadian Bacterial Surveillance Network.

1996 ◽  
Vol 40 (9) ◽  
pp. 2190-2193 ◽  
Author(s):  
A E Simor ◽  
M Louie ◽  
D E Low
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Beta Lactam ◽  
Surveillance Network ◽  
Antibiotic Resistant ◽  
Intermediate Resistance ◽  
Resistant Strains ◽  
High Level ◽  
Level Resistance

The antimicrobial susceptibilities of 1,089 clinical isolates of Streptococcus pneumoniae obtained from 39 laboratories across Canada between October 1994 and August 1995 were determined. A total of 91 isolates (8.4%) demonstrated intermediate resistance (MIC, 0.1 to 1.0 microgram/ml) and 36 (3.3%) had high-level resistance (MIC, > or = 2.0 micrograms/ml) to penicillin. Penicillin-resistant strains were more likely to have been recovered from normally sterile sites (P = 0.005) and to be cross-resistant to several beta-lactam and non-beta-lactam antimicrobial agents (P < 0.05). These results indicate that there has been a recent significant increase in the prevalence of antibiotic-resistant S. pneumoniae in Canada.

scholarly journals Sparfloxacin Resistance in Clinical Isolates ofStreptococcus pneumoniae: Involvement of Multiple Mutations in gyrA and parC Genes

1998 ◽  
Vol 42 (9) ◽  
pp. 2193-2196 ◽  
Author(s):  
Hideki Taba ◽  
Nobuchika Kusano
Keyword(s):  
Streptococcus Pneumoniae ◽  
Amino Acid ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Clinical Isolates ◽  
Amino Acid Substitutions ◽  
Sequencing Analysis ◽  
High Level ◽  
Additional Nucleotide ◽  
Level Resistance

ABSTRACT Antimicrobial susceptibility testing revealed among 150 clinical isolates of Streptococcus pneumoniae 4 pneumococcal isolates with resistance to fluoroquinolones (MIC of ciprofloxacin, ≥32 μg/ml; MIC of sparfloxacin, ≥16 μg/ml). Gene amplification and sequencing analysis of gyrA andparC revealed nucleotide changes leading to amino acid substitutions in both GyrA and ParC of all four fluoroquinolone-resistant isolates. In the case of strains 182 and 674 for which sparfloxacin MICs were 16 and 64 μg/ml, respectively, nucleotide changes were detected at codon 81 in gyrA and codon 79 in parC; these changes led to an Ser→Phe substitution in GyrA and an Ser→Phe substitution in ParC. Strains 354 and 252, for which sparfloxacin MICs were 128 μg/ml, revealed multiple mutations in both gyrA and parC. These strains exhibited nucleotide changes at codon 85 leading to a Glu→Lys substitution in GyrA, in addition to Ser-79→Tyr and Lys-137→Asn substitutions in ParC. Moreover, strain 252 showed additional nucleotide changes at codon 93, which led to a Trp→Arg substitution in GyrA. These results suggest that sparfloxacin resistance could be due to the multiple mutations in GyrA and ParC. However, it is possible that other yet unidentified mutations may also be involved in the high-level resistance to fluoroquinolones in S. pneumoniae.

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