scholarly journals Capsule Homology Does Not Increase the Frequency of Transformation of Linked Penicillin Binding Proteins PBP 1a and PBP 2x in Streptococcus pneumoniae

2005 ◽  
Vol 49 (4) ◽  
pp. 1591-1592 ◽  
Author(s):  
Krzysztof Trzciński ◽  
Adam MacNeil ◽  
Keith P. Klugman ◽  
Marc Lipsitch

ABSTRACT Penicillin resistance is mainly confined to a limited number of Streptococcus pneumoniae serotypes. Given linkage between the capsular biosynthesis locus and two penicillin binding proteins, we tested whether capsule homology increases transformation rates of penicillin resistance. Transformation rates in homologous donor-recipient pairs were no higher than expected, falsifying this hypothesis.


2013 ◽  
Vol 58 (3) ◽  
pp. 1397-1403 ◽  
Author(s):  
Fereshteh Fani ◽  
Philippe Leprohon ◽  
George G. Zhanel ◽  
Michel G. Bergeron ◽  
Marc Ouellette

ABSTRACTAlterations in penicillin-binding proteins, the target enzymes for β-lactam antibiotics, are recognized as primary penicillin resistance mechanisms inStreptococcus pneumoniae. Few studies have analyzed penicillin resistance at the genome scale, however, and we report the sequencing ofS. pneumoniaeR6 transformants generated while reconstructing the penicillin resistance phenotypes from three penicillin-resistant clinical isolates by serial genome transformation. The genome sequences of the three last-level transformants T2-18209, T5-1983, and T3-55938 revealed that 16.2 kb, 82.7kb, and 137.2 kb of their genomes had been replaced with 5, 20, and 37 recombinant sequence segments derived from their respective parental clinical isolates, documenting the extent of DNA transformation between strains. A role in penicillin resistance was confirmed for some of the mutations identified in the transformants. Several multiple recombination events were also found to have happened at single loci coding for penicillin-binding proteins (PBPs) that increase resistance. Sequencing of the transformants with MICs for penicillin similar to those of the parent clinical strains confirmed the importance of mosaic PBP2x, -2b, and -1a as a driving force in penicillin resistance. A role in resistance for mosaic PBP2a was also observed for two of the resistant clinical isolates.



2016 ◽  
Vol 1 (2) ◽  
pp. 22 ◽  
Author(s):  
Navindra Kumari Palanisamy ◽  
Parasakthi Navaratnam ◽  
Shamala Devi Sekaran

Introduction: Streptococcus pneumoniae is an important bacterial pathogen, causing respiratory infection. Penicillin resistance in S. pneumoniae is associated with alterations in the penicillin binding proteins, while resistance to macrolides is conferred either by the modification of the ribosomal target site or efflux mechanism. This study aimed to characterize S. pneumoniae and its antibiotic resistance genes using 2 sets of multiplex PCRs. Methods: A quintuplex and triplex PCR was used to characterize the pbp1A, ermB, gyrA, ply, and the mefE genes. Fifty-eight penicillin sensitive strains (PSSP), 36 penicillin intermediate strains (PISP) and 26 penicillin resistance strains (PRSP) were used. Results: Alteration in pbp1A was only observed in PISP and PRSP strains, while PCR amplification of the ermB or mefE was observed only in strains with reduced susceptibility to erythromycin. The assay was found to be sensitive as simulated blood cultures showed the lowest level of detection to be 10cfu. Conclusions: As predicted, the assay was able to differentiate penicillin susceptible from the non-susceptible strains based on the detection of the pbp1A gene, which correlated with the MIC value of the strains.



2007 ◽  
Vol 51 (9) ◽  
pp. 3404-3406 ◽  
Author(s):  
Cheng-Hsun Chiu ◽  
Lin-Hui Su ◽  
Yhu-Chering Huang ◽  
Jui-Chia Lai ◽  
Hsiu-Ling Chen ◽  
...  

ABSTRACT The rate of nonsusceptibility of penicillin-resistant Streptococcus pneumoniae strains to ceftriaxone increased significantly in Taiwan in 2005. Approximately 90% of the ceftriaxone-nonsusceptible isolates were found to be of four major serotypes (serotypes 6B, 14, 19F, and 23F). Seven amino acid alterations in the penicillin-binding protein 2B transpeptidase-encoding region specifically contributed to the resistance.



1999 ◽  
Vol 33 (4) ◽  
pp. 673-678 ◽  
Author(s):  
Regine Hakenbeck ◽  
Thorsten Grebe ◽  
Dorothea Zahner ◽  
Jeffry B. Stock


ORL ◽  
2006 ◽  
Vol 68 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Muneki Hotomi ◽  
Dewan S. Billal ◽  
Jun Shimada ◽  
Masaki Suzumoto ◽  
Kazuma Yamauchi ◽  
...  


1988 ◽  
Vol 22 (6) ◽  
pp. 791-800 ◽  
Author(s):  
L. J. Chalkley ◽  
H. J. Koornhof


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