scholarly journals Resistance to penicillin and identification of penicillinase-producing Neisseria gonorrhoeae among clinical isolates in Thailand.

1980 ◽  
Vol 18 (2) ◽  
pp. 360-361 ◽  
Author(s):  
J W Crum ◽  
C Duangmani ◽  
S Vibulyasekha ◽  
K Suthisomboon
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Clinical Isolates ◽  
Resistance To Penicillin

scholarly journals Overexpression of the MtrC-MtrD-MtrE Efflux Pump Due to an mtrR Mutation Is Required for Chromosomally Mediated Penicillin Resistance in Neisseria gonorrhoeae

2002 ◽  
Vol 184 (20) ◽  
pp. 5619-5624 ◽  
Author(s):  
Wendy L. Veal ◽  
Robert A. Nicholas ◽  
William M. Shafer
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Base Pair ◽  
Efflux Pump ◽  
Penicillin Resistance ◽  
Single Base ◽  
Base Pair Deletion ◽  
Resistance To Penicillin ◽  
Single Base Pair ◽  
High Level ◽  
Level Resistance

ABSTRACT The importance of the mtrCDE-encoded efflux pump in conferring chromosomally mediated penicillin resistance on certain strains of Neisseria gonorrhoeae was determined by using genetic derivatives of penicillin-sensitive strain FA19 bearing defined mutations (mtrR, penA, and penB) donated by a clinical isolate (FA6140) expressing high-level resistance to penicillin and antimicrobial hydrophobic agents (HAs). When introduced into strain FA19 by transformation, a single base pair deletion in the mtrR promoter sequence from strain FA6140 was sufficient to provide high-level resistance to HAs (e.g., erythromycin and Triton X-100) but only a twofold increase in resistance to penicillin. When subsequent mutations in penA and porIB were introduced from strain FA6140 into strain WV30 (FA19 mtrR) by transformation, resistance to penicillin increased incrementally up to a MIC of 1.0 μg/ml. Insertional inactivation of the gene (mtrD) encoding the membrane transporter component of the Mtr efflux pump in these transformant strains and in strain FA6140 decreased the MIC of penicillin by 16-fold. Genetic analyses revealed that mtrR mutations, such as the single base pair deletion in its promoter, are needed for phenotypic expression of penicillin and tetracycline resistance afforded by the penB mutation. As penB represents amino acid substitutions within the third loop of the outer membrane PorIB protein that modulate entry of penicillin and tetracycline, the results presented herein suggest that PorIB and the MtrC-MtrD-MtrE efflux pump act synergistically to confer resistance to these antibiotics.

scholarly journals Mosaic-Like Structure of Penicillin-Binding Protein 2 Gene (penA) in Clinical Isolates of Neisseria gonorrhoeae with Reduced Susceptibility to Cefixime

2002 ◽  
Vol 46 (12) ◽  
pp. 3744-3749 ◽  
Author(s):  
Satoshi Ameyama ◽  
Shoichi Onodera ◽  
Masahiro Takahata ◽  
Shinzaburo Minami ◽  
Nobuko Maki ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Neisseria Gonorrhoeae ◽  
Neisseria Meningitidis ◽  
Binding Protein ◽  
Clinical Isolates ◽  
Penicillin Binding Protein ◽  
Gene Sequences ◽  
Neisseria Flavescens ◽  
Neisseria Perflava

ABSTRACT Neisseria gonorrhoeae strains with reduced susceptibility to cefixime (MICs, 0.25 to 0.5 μg/ml) were isolated from male urethritis patients in Tokyo, Japan, in 2000 and 2001. The resistance to cephems including cefixime and penicillin was transferred to a susceptible recipient, N. gonorrhoeae ATCC 19424, by transformation of the penicillin-binding protein 2 gene (penA) that had been amplified by PCR from a strain with reduced susceptibility to cefixime (MIC, 0.5 μg/ml). The sequences of penA in the strains with reduced susceptibilities to cefixime were different from those of other susceptible isolates and did not correspond to the reported N. gonorrhoeae penA gene sequences. Some regions in the transpeptidase-encoding domain in this penA gene were similar to those in the penA genes of Neisseria perflava (N. sicca), Neisseria cinerea, Neisseria flavescens, and Neisseria meningitidis. These results showed that a mosaic-like structure in the penA gene conferred reductions in the levels of susceptibility of N. gonorrhoeae to cephems and penicillin in a manner similar to that found for N. meningitidis and Streptococcus pneumoniae.

Resistance, molecular characterization and viability of Neisseria gonorrhoeae recent clinical isolates

2021 ◽  
Vol 156 (5) ◽  
pp. 249-250
Author(s):  
Elizabeth Calatrava-Hernández ◽  
Carla Foronda-García-Hidalgo ◽  
José Gutiérrez-Fernández
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Molecular Characterization ◽  
Clinical Isolates

scholarly journals IDENTIFICATION OF AMPC Β-LACTAMASE-PRODUCING CLINICAL ISOLATES OF ESCHERICHIA COLI

2017 ◽  
Vol 10 (12) ◽  
pp. 357
Author(s):  
Tanushree Barua Gupta ◽  
Malini Shariff ◽  
Thukral Ss ◽  
S.s Thukral
Keyword(s):  
Escherichia Coli ◽  
Detection Method ◽  
Clinical Isolates ◽  
Confirmatory Test ◽  
Chain Reaction ◽  
E Coli ◽  
Resistance To Penicillin ◽  
Polymerase Chain ◽  
Third Generation Cephalosporins

  Objective: Indiscriminate use of β-lactam antibiotics has resulted in the emergence of β-lactamase enzymes. AmpC β-lactamases, in particular, confer resistance to penicillin, first-, second-, and third-generation cephalosporins as well as monobactams and are responsible for antibiotic resistance in nosocomial pathogens. Therefore, this study was undertaken to screen nosocomial Escherichia coli isolates for the presence and characterization of AmpC β-lactamases. The study also envisaged on the detection of inducible AmpC β-lactamases and extended-spectrum β-lactamases (ESBLs) in AmpC β-lactamase-producing E. coli.Methods: A total of 102 clinical isolates of E. coli, were subjected to cefoxitin screening, and screen-positive isolates were further subjected to inhibitor-based detection method, phenotypic confirmatory test, disc antagonism test, polymerase chain reaction (PCR), and isoelectric focusing (IEF).Results: In this study, 33% of E. coli were resistant to cefoxitin, of which 35% were found to be positive for AmpC β-lactamase by inhibitor-based phenotypic test. Of the AmpC-positive isolates, 83% were positive for ESBLs, whereas 25% were producing inducible AmpC β-lactamases. PCR and IEF showed CIT and EBC types of AmpC β-lactamases present in the tested isolates.Conclusion: Our study showed the presence of inducible AmpC enzymes and ESBLs in E. coli isolates and PCR identified more isolates to be AmpC producers.

scholarly journals Molecular Analyses of TEM Genes and Their Corresponding Penicillinase-Producing Neisseria gonorrhoeae Isolates in Bangkok, Thailand

2011 ◽  
Vol 56 (2) ◽  
pp. 916-920 ◽  
Author(s):  
Shu-ichi Nakayama ◽  
Chanwit Tribuddharat ◽  
Sasiprapa Prombhul ◽  
Ken Shimuta ◽  
Somporn Srifuengfung ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Public Health Problem ◽  
Major Public Health Problem ◽  
Sexual Network ◽  
Genetic Event ◽  
Content Type ◽  
Extended Spectrum ◽  
Resistance To Penicillin ◽  
High Level ◽  
International Awareness

ABSTRACTNeisseria gonorrhoeaeis a major public health problem globally, especially because the bacterium has developed resistance to most antimicrobials introduced for first-line treatment of gonorrhea. In the present study, 96N. gonorrhoeaeisolates with high-level resistance to penicillin from 121 clinical isolates in Thailand were examined to investigate changes related to their plasmid-mediated penicillin resistance and their molecular epidemiological relationships. A β-lactamase (TEM) gene variant,blaTEM-135, that may be a precursor in the transitional stage of a traditionalblaTEM-1gene into an extended-spectrum β-lactamase (ESBL), possibly causing high resistance to all extended-spectrum cephalosporins inN. gonorrhoeae, was identified. Clonal analysis using multilocus sequence typing (MLST) andN. gonorrhoeaemultiantigen sequence typing (NG-MAST) revealed the existence of a sexual network among patients from Japan and Thailand. Molecular analysis of theblaTEM-135gene showed that the emergence of this allele might not be a rare genetic event and that the allele has evolved in different plasmid backgrounds, which results possibly indicate that it is selected due to antimicrobial pressure. The presence of theblaTEM-135allele in the penicillinase-producingN. gonorrhoeaepopulation may call for monitoring for the possible emergence of ESBL-producingN. gonorrhoeaein the future. This study identified ablaTEMvariant (blaTEM-135) that is a possible intermediate precursor for an ESBL, which warrants international awareness.

scholarly journals Amino Acid Substitutions in Mosaic Penicillin-Binding Protein 2 Associated with Reduced Susceptibility to Cefixime in Clinical Isolates of Neisseria gonorrhoeae

2006 ◽  
Vol 50 (11) ◽  
pp. 3638-3645 ◽  
Author(s):  
Sho Takahata ◽  
Nami Senju ◽  
Yumi Osaki ◽  
Takuji Yoshida ◽  
Takashi Ida
Keyword(s):  
Amino Acid ◽  
Neisseria Gonorrhoeae ◽  
Molecular Mechanisms ◽  
Binding Protein ◽  
Complete Sequence ◽  
Clinical Isolates ◽  
Amino Acid Substitutions ◽  
Penicillin Binding Protein ◽  
Fourfold Increase ◽  
Genes Encoding

ABSTRACT The molecular mechanisms of reduced susceptibility to cefixime in clinical isolates of Neisseria gonorrhoeae, particularly amino acid substitutions in mosaic penicillin-binding protein 2 (PBP2), were examined. The complete sequence of ponA, penA, and por genes, encoding, respectively, PBP1, PBP2, and porin, were determined for 58 strains isolated in 2002 from Japan. Replacement of leucine 421 by proline in PBP1 and the mosaic-like structure of PBP2 were detected in 48 strains (82.8%) and 28 strains (48.3%), respectively. The presence of mosaic PBP2 was the main cause of the elevated cefixime MIC (4- to 64-fold). In order to identify the mutations responsible for the reduced susceptibility to cefixime in isolates with mosaic PBP2, penA genes with various mutations were transferred to a susceptible strain by genetic transformation. The susceptibility of partial recombinants and site-directed mutants revealed that the replacement of glycine 545 by serine (G545S) was the primary mutation, which led to a two- to fourfold increase in resistance to cephems. Replacement of isoleucine 312 by methionine (I312M) and valine 316 by threonine (V316T), in the presence of the G545S mutation, reduced susceptibility to cefixime, ceftibuten, and cefpodoxime by an additional fourfold. Therefore, three mutations (G545S, I312M, and V316T) in mosaic PBP2 were identified as the amino acid substitutions responsible for reduced susceptibility to cefixime in N. gonorrhoeae.

Evaluation of Susceptibilities to Carbapenems and Faropenem Against Cephalosporin-Resistant Neisseria gonorrhoeae Clinical Isolates with penA Mosaic Alleles

2019 ◽  
Vol 25 (3) ◽  
pp. 427-433 ◽  
Author(s):  
Yoshiki Hiyama ◽  
Satoshi Takahashi ◽  
Toyotaka Sato ◽  
Masaaki Shinagawa ◽  
Yukari Fukushima ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Clinical Isolates

scholarly journals DNA gyrase mutations in quinolone-resistant clinical isolates of Neisseria gonorrhoeae

1995 ◽  
Vol 39 (2) ◽  
pp. 561-563 ◽  
Author(s):  
T. Deguchi ◽  
M. Yasuda ◽  
M. Asano ◽  
K. Tada ◽  
H. Iwata ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Dna Gyrase ◽  
Clinical Isolates

scholarly journals Resistance to penicillin-streptomycin synergy among clinical isolates of viridans streptococci.

1983 ◽  
Vol 24 (6) ◽  
pp. 871-875 ◽  
Author(s):  
B F Farber ◽  
G M Eliopoulos ◽  
J I Ward ◽  
K Ruoff ◽  
R C Moellering
Keyword(s):  
Clinical Isolates ◽  
Viridans Streptococci ◽  
Resistance To Penicillin
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