scholarly journals Antimicrobial resistance, penicillin-binding protein sequences, and pilus islet carriage in relation to clonal evolution of Streptococcus pneumoniae serotype 19A in Russia, 2002–2013

2017 ◽  
Vol 145 (8) ◽  
pp. 1708-1719 ◽  
Author(s):  
N. MAYANSKIY ◽  
T. SAVINOVA ◽  
N. ALYABIEVA ◽  
O. PONOMARENKO ◽  
E. BRZHOZOVSKAYA ◽  
...  
Keyword(s):  
Molecular Detection ◽  
Susceptibility Testing ◽  
Clonal Complex ◽  
Binding Protein ◽  
Clonal Evolution ◽  
Clonal Structure ◽  
Penicillin Binding Protein ◽  
Non Invasive ◽  
Sequence Types

SUMMARYClonal changes of serotype 19A pneumococci have been appreciated in conjunction with growing prevalence of this serotype after implementation of the seven-valent pneumococcal conjugate vaccine (PCV7). In the present study, we characterized serotype 19A pneumococci collected in Russia within a decade preceding the implementation of PCV vaccination and described their clonal evolution. We retrospectively analyzed non-invasive serotype 19A isolates collected in 2002–2013. All isolates were subjected to multilocus sequence typing, antimicrobial susceptibility testing, determination of macrolide resistance genotype, molecular detection of pilus islet (PI) carriage, sequencing of penicillin-binding protein (PBP) genes. A total of 49 serotype 19A isolates represented 25 sequence types, of which 14 were newly described. The majority of isolates were distributed among clonal complex (CC) 663 (28%), CC230 (25%), CC156, and CC320 (14% each). CC663 and CC156 dominated in 2003, but were replaced by CC230 and CC320 later on; CC320 was only evident starting 2010. All isolates of CC663 and CC156 carried PI1; CC320 possessed both PI1 and PI2. The overall rate of altered amino acids in penicillin-nonsusceptible isolates was 13·9%, 7·2%, and 8·7% for PBP1a, PBP2b, and PBP2x, respectively. Our findings demonstrate that the clonal structure of serotype 19A pneumococci may evolve without PCV pressure.

scholarly journals Determination of the cleavage site involved in C-terminal processing of penicillin-binding protein 3 of Escherichia coli.

1989 ◽  
Vol 171 (11) ◽  
pp. 5890-5893 ◽  
Author(s):  
H Nagasawa ◽  
Y Sakagami ◽  
A Suzuki ◽  
H Suzuki ◽  
H Hara ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cleavage Site ◽  
Binding Protein ◽  
Penicillin Binding Protein

scholarly journals Carbapenem-NonsusceptibleHaemophilus influenzaewith Penicillin-Binding Protein 3 Containing an Amino Acid Insertion

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Kazuki Kitaoka ◽  
Kouji Kimura ◽  
Hiromitsu Kitanaka ◽  
Hirotsugu Banno ◽  
Wanchun Jin ◽  
...  
Keyword(s):  
Amino Acid ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Efflux Pump ◽  
Binding Protein ◽  
Antimicrobial Susceptibility Testing ◽  
Nucleotide Sequence Analysis ◽  
Penicillin Binding Protein ◽  
Binding Assays ◽  
Content Type

ABSTRACTThe prevalence of β-lactamase-negative ampicillin-resistant (BLNAR)Haemophilus influenzaehas become a clinical concern. In BLNAR isolates, amino acid substitutions in penicillin-binding protein 3 (PBP3) are relevant to the β-lactam resistance. Carbapenem-nonsusceptibleH. influenzaeisolates have been rarely reported. Through antimicrobial susceptibility testing, nucleotide sequence analysis offtsI, encoding PBP3, and the utilization of a collection ofH. influenzaeclinical isolates in our laboratory, we obtained a carbapenem-nonsusceptible clinical isolate (NUBL1772) that possesses an altered PBP3 containing V525_N526insM. The aim of this study was to reveal the effect of altered PBP3 containing V525_N526insM on reduced carbapenem susceptibility. After generating recombinant strains with alteredftsI, we performed antimicrobial susceptibility testing and competitive binding assays with fluorescent penicillin (Bocillin FL) and carbapenems. Elevated carbapenem MICs were found for the recombinant strain harboring the entireftsIgene of NUBL1772. The recombinant PBP3 of NUBL1772 also exhibited reduced binding to carbapenems. These results demonstrate that altered PBP3 containing V525_N526insM influences the reduced carbapenem susceptibility. The revertant mutant lacking the V525_N526insM exhibited lower MICs for carbapenems than NUBL1772, suggesting that this insertion affects reduced carbapenem susceptibility. The MICs of β-lactams for NUBL1772 were higher than those for the recombinant possessingftsIof NUBL1772. NUBL1772 harbored AcrR with early termination, resulting in low-level transcription ofacrBand high efflux pump activity. These findings suggest that the disruption of AcrR also contributes to the reduced carbapenem susceptibility found in NUBL1772. Our results provide the first evidence that the altered PBP3 containing V525_N526insM is responsible for the reduced susceptibility to carbapenems inH. influenzae.

scholarly journals Diversity of β-Lactam Resistance-Conferring Amino Acid Substitutions in Penicillin-Binding Protein 3 of Haemophilus influenzae

2002 ◽  
Vol 46 (7) ◽  
pp. 2208-2218 ◽  
Author(s):  
Henri Dabernat ◽  
Catherine Delmas ◽  
Martine Seguy ◽  
Roseline Pelissier ◽  
Genevieve Faucon ◽  
...  
Keyword(s):  
Amino Acid ◽  
Haemophilus Influenzae ◽  
Binding Protein ◽  
Amino Acid Substitutions ◽  
Penicillin Binding Protein ◽  
Gene Encoding ◽  
Peptidoglycan Synthesis ◽  
Group I ◽  
Adults And Children

ABSTRACT The sequences of the ftsI gene, encoding the transpeptidase domain of penicillin binding protein (PBP) 3A and/or PBP 3B, which are involved in septal peptidoglycan synthesis, were determined for 108 clinical strains of Haemophilus influenzae with reduced susceptibility to β-lactam antibiotics with or without β-lactamase production and were compared to those of the ampicillin-susceptible Rd strain and ampicillin-susceptible clinical isolates. The sequences have 18 different mutation patterns and were classified into two groups on the basis of amino acid substitutions deduced from the nucleotide sequences located between bp 960 and 1618 of the ftsI gene. In group I strains (n = 7), His-517 was substituted for Arg-517. In group II strains (n = 101), Lys-526 was substituted for Asn-526. In subgroup IIa (n = 5; H. influenzae ATCC 49247), the only observed substitution was Lys-526 for Asn-526; in subgroup IIb (n = 56), Val-502 was substituted for Ala-502 (n = 13), along with several other substitutions: Asn-350 for Asp-350 (n = 15), Asn-350 for Asp-350 and Glu-490 for Gly-490 (n = 14), and Asn-350 for Asp-350 and Ser-437 for Ala-437 (n = 5). In subgroup IIc (n = 25), Thr-502 was substituted for Ala-502. In subgroup IId, Val-449 was substituted for Ile-449 (n = 15). The MICs of β-lactam antibiotics for the 108 strains were to 8 to 16 times the MICs for susceptible strains. The strains, isolated from both adults and children, were analyzed for genetic relationship by pulsed-field gel electrophoresis and by determination of ftsI sequence phylogeny. Both analyses revealed the lack of clonality and the heterogeneity of the strains, but some clusters suggest the spread and/or persistence of a limited number of strains of the same pulsotype and pattern of amino acid substitutions. Reduced susceptibility to β-lactam, brought about by mutations of the ftsI gene, is becoming a frequent phenomenon, affecting both strains that produce β-lactamase and those that do not. The level of resistance remains low but opens the way to greater resistance in the future.

scholarly journals Multilocus sequence types of invasive Corynebacterium diphtheriae isolated in the Rio de Janeiro urban area, Brazil

2011 ◽  
Vol 140 (4) ◽  
pp. 617-620 ◽  
Author(s):  
S. Z. VIGUETTI ◽  
L. G. C. PACHECO ◽  
L. S. SANTOS ◽  
S. C. SOARES ◽  
F. BOLT ◽  
...  
Keyword(s):  
Urban Area ◽  
Rio De Janeiro ◽  
Clonal Complex ◽  
Genetic Relationships ◽  
Invasive Disease ◽  
Corynebacterium Diphtheriae ◽  
Non Invasive ◽  
Negative Results ◽  
Invasive Infections ◽  
Sequence Types

SUMMARYInvasive infections caused by Corynebacterium diphtheriae in vaccinated and non-vaccinated individuals have been reported increasingly. In this study we used multilocus sequence typing (MLST) to study genetic relationships between six invasive strains of this bacterium isolated solely in the urban area of Rio de Janeiro, Brazil, during a 10-year period. Of note, all the strains rendered negative results in PCR reactions for the tox gene, and four strains presented an atypical sucrose-fermenting ability. Five strains represented new sequence types. MLST results did not support the hypothesis that invasive (sucrose-positive) strains of C. diphtheriae are part of a single clonal complex. Instead, one of the main findings of the study was that such strains can be normally found in clonal complexes with strains related to non-invasive disease. Comparative analyses with C. diphtheriae isolated in different countries provided further information on the geographical circulation of some sequence types.

INFLUENCE OF OFFICE BLEACHING SYSTEMS ON THE RESISTANCE OF HARD TOOTH TISSUES

2020 ◽  
pp. 119-125
Author(s):  
Magsumova O.A. ◽  
Postnikov M.A. ◽  
Ryskina E.A. ◽  
Tkach T.M. ◽  
Polkanova V.A.
Keyword(s):  
Informed Consent ◽  
Oral Fluid ◽  
Personal Data ◽  
Acid Resistance ◽  
Non Invasive ◽  
Hard Tissues ◽  
Voluntary Informed Consent

One of the non-invasive methods for treating discoloration of hard tooth tissues is teeth whitening. The aim of this work is to assess the dynamics of changes in the acid resistance of enamel and hard tissues of teeth and the rate of its remineralization after the procedure of office teeth whitening. The study involved 123 patients aged 18 to 35 years with discoloration of various origins, with the color of hard tooth tissues on the Vita Classic A2 scale and darker. Before performing the office, teeth whitening procedure, all patients gave their written voluntary informed consent to participate in this study, as well as consent to the processing of personal data. Depending on the chosen method of office teeth whitening, patients were divided into 3 groups. The resistance of hard tooth tissues was judged based on the determination of TOER and CASRE tests. These indicators were determined at various times (5 days before the office teeth whitening procedure, 5 days after it, after 14, 30 days and 6 months). Regardless of the chosen whitening system, the office teeth whitening procedure is accompanied by a decrease in the enamel's resistance to acids and a decrease in the rate of its remineralization. The remineralizing function of oral fluid promotes the positive dynamics of the studied parameters after 14 days and after 30 days values increased due to the appointment of remineralizing therapy to all patients in 2 weeks after the teeth whitening procedure. After 6 months, all patients had high enamel resistance and the rate of its remineralization.

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