Genetic analysis of clinical isolates of Streptococcus pneumoniae with high-level resistance to expanded-spectrum cephalosporins

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.

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.9.2193 ◽

1998 ◽

Vol 42 (9) ◽

pp. 2193-2196 ◽

Cited By ~ 28

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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Molecular aspects of high-level resistance to sulbactam-cefoperazone in Klebsiella oxytoca clinical isolates.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.40.9.1988 ◽

1996 ◽

Vol 40 (9) ◽

pp. 1988-1994 ◽

Cited By ~ 7

Author(s):

K Kimura ◽

Y Arakawa ◽

S Ohsuka ◽

H Ito ◽

K Suzuki ◽

...

Keyword(s):

Klebsiella Oxytoca ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Point Of View ◽

Clinical Isolates ◽

Beta Lactamase ◽

Beta Lactamases ◽

Molecular Aspects ◽

High Level ◽

Level Resistance

Nine Klebsiella oxytoca strains which demonstrated resistance to the combination of sulbactam and cefoperazone were isolated from geographically separate hospitals in Japan in 1995. Among them, K. oxytoca SB23 showed high-level resistance to sulbactam-cefoperazone (MIC > 128 micrograms/ml) and aztreonam (MIC, 128 micrograms/ml). The sulbactam-cefoperazone resistance was not transferred from strain SB23 to Escherichia coli CSH2 by conjugation, beta-Lactamase RbiA, produced by strain SB23, was purified, and the molecular mass was estimated to be 29 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Kinetic parameters for RbiA revealed that cefoperazone and aztreonam were hydrolyzed efficiently by this enzyme. Moreover, ceftazidime and imipenem were also hydrolyzed weakly by RbiA, although strain SB23 did not show any resistance to these agents. Clavulanate, sulbactam, and tazobactam failed to block the hydrolysis of cefoperazone by RbiA. The structural gene of RbiA (blaRBI) was cloned and sequenced, and the deduced amino acid sequence of RbiA demonstrated high-level similarities to those of the beta-lactamases found in K. oxytoca D488, E23004, and plasmid-mediated MEN-1, which have been classified into Bush functional group 2be. Although RbiA demonstrates high-level molecular similarity to the enzymes in group 2be, from an enzymological point of view, this enzyme might be differentiated from the enzymes in that group. Hybridization analysis revealed that beta-lactamase genes highly similar to blaRBI were generally encoded on the chromosome of the sulbactam-cefoperazone-resistant clinical isolates of K. oxytoca tested in the study, despite their different derivations. This observation suggests that sulbactam-cefoperazone-resistant A. oxytoca strains which produce RbiA-type beta-lactamases have been proliferating in many hospitals in Japan.

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Rapid Emergence of High-Level Resistance to Quinolones in Campylobacter jejuni Associated with Mutational Changes in gyrA and parC

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.12.3276 ◽

1998 ◽

Vol 42 (12) ◽

pp. 3276-3278 ◽

Cited By ~ 55

Author(s):

Amera Gibreel ◽

Eva Sjögren ◽

Bertil Kaijser ◽

Bengt Wretlind ◽

Ola Sköld

Keyword(s):

Campylobacter Jejuni ◽

Quinolone Resistance ◽

Clinical Isolates ◽

High Level ◽

Chromosomal Mutations ◽

Rapid Emergence ◽

Level Resistance

ABSTRACT Quinolone resistance in clinical isolates of Campylobacter jejuni in Sweden increased more than 20-fold at the beginning of the 1990s. Resistance to 125 μg of ciprofloxacin per ml in clinical isolates was associated with chromosomal mutations in C. jejuni leading to a Thr-86-Ile substitution in thegyrA product and a Arg-139-Gln substitution in theparC product.

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High-level resistance to gentamicin in clinical isolates of Streptococcus (Enterococcus) faecium.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.32.10.1528 ◽

1988 ◽

Vol 32 (10) ◽

pp. 1528-1532 ◽

Cited By ~ 53

Author(s):

G M Eliopoulos ◽

C Wennersten ◽

S Zighelboim-Daum ◽

E Reiszner ◽

D Goldmann ◽

...

Keyword(s):

Enterococcus Faecium ◽

Clinical Isolates ◽

High Level ◽

Level Resistance

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.5.1252 ◽

1999 ◽

Vol 43 (5) ◽

pp. 1252-1255 ◽

Cited By ~ 60

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.

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

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/48.2.316 ◽

2001 ◽

Vol 48 (2) ◽

pp. 316-317 ◽

Cited By ~ 4

Author(s):

P.-R. Hsueh

Keyword(s):

Streptococcus Pneumoniae ◽

Clinical Isolate ◽

High Level ◽

Level Resistance

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.4.1419-1422.2003 ◽

2003 ◽

Vol 47 (4) ◽

pp. 1419-1422 ◽

Cited By ~ 16

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.

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Susceptibility trends of zoliflodacin against multidrug-resistant Neisseria gonorrhoeae clinical isolates in Nanjing, China (2014-2018)

10.1101/2020.05.04.078055 ◽

2020 ◽

Author(s):

Wenjing Le ◽

Xiaohong Su ◽

Xiangdi Lou ◽

Xuechun Li ◽

Xiangdong Gong ◽

...

Keyword(s):

Neisseria Gonorrhoeae ◽

Dna Sequencing ◽

Multidrug Resistant ◽

Quinolone Resistance ◽

Clinical Isolates ◽

Drug Resistant ◽

Extended Spectrum ◽

High Level ◽

Level Resistance

ABSTRACTPreviously, we reported potent activity of a novel spiropyrimidinetrione, zoliflodacin, against N. gonorrhoeae isolates from symptomatic men in Nanjing, China, collected in 2013. Here, we investigated trends of susceptibilities of zoliflodacin in 986 gonococcal isolates collected from men between 2014 and 2018. N. gonorrhoeae isolates were tested for susceptibility to zoliflodacin and seven other antibiotics. Mutations in gyrA, gyrB, parC and parE genes were determined by PCR and DNA sequencing. The MIC of zoliflodacin for N. gonorrhoeae ranged from ≤0.002 to 0.25 mg/L; the overall MIC50s and MIC90s were 0.06 mg/L and 0.125mg/L in 2018, increasing two-fold from 2014. However, the percent of isolates with lower zoliflodacin MICs declined in each year sequentially while the percent with higher MICs increased yearly (P≤0.00001). All isolates were susceptible to spectinomycin but resistant to ciprofloxacin (MIC ≥1 μg/ml); 21.2% (209/986) were resistant to azithromycin (≥1 μg/ml), 43.4% (428/986) were penicillinase-producing (PPNG), 26.9% (265/986) tetracycline-resistant (TRNG) and 19.4% (191/986) were multi-drug resistant (MDR) isolates. Among 143 isolates with higher zoliflodacin MICs (0.125-0.25 mg/L), all had quinolone resistance associated double or triple mutations in gyrA; 139/143 (97.2%) also had mutations in parC. There were no D429N/A and/or K450T mutations in GyrB identified in the 143 isolates with higher zoliflodacin MICs; a S467N mutation in GyrB was identified in one isolate. We report that zoliflodacin has excellent in vitro activity against clinical gonococcal isolates, including those with high-level resistance to ciprofloxacin, azithromycin and extended spectrum cephalosporins.

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.6.1480 ◽

1999 ◽

Vol 43 (6) ◽

pp. 1480-1483 ◽

Cited By ~ 41

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.

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