Extensive re-modelling of the transpeptidase domain of penicillin-binding protein 2B of a penicillin-resistant South African isolate of Streptococcus pneumoniae

1989 ◽  
Vol 3 (1) ◽  
pp. 95-102 ◽  
Author(s):  
C. G. Dowson ◽  
A. Hutchison ◽  
B. G. Spratt
Keyword(s):  
Streptococcus Pneumoniae ◽  
South African ◽  
Binding Protein ◽  
Penicillin Binding Protein ◽  
South African Isolate ◽  
African Isolate

scholarly journals Increasing Ceftriaxone Resistance and Multiple Alterations of Penicillin-Binding Proteins among Penicillin-Resistant Streptococcus pneumoniae Isolates in Taiwan

2007 ◽  
Vol 51 (9) ◽  
pp. 3404-3406 ◽  
Author(s):  
Cheng-Hsun Chiu ◽  
Lin-Hui Su ◽  
Yhu-Chering Huang ◽  
Jui-Chia Lai ◽  
Hsiu-Ling Chen ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Amino Acid ◽  
Binding Proteins ◽  
Binding Protein ◽  
Penicillin Binding Protein ◽  
Penicillin Binding Proteins

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.

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.

scholarly journals Directly repeated insertion of 9-nucleotide sequence detected in penicillin-binding protein 2B gene of penicillin-resistant Streptococcus pneumoniae.

1996 ◽  
Vol 40 (5) ◽  
pp. 1257-1259 ◽  
Author(s):  
A Yamane ◽  
H Nakano ◽  
Y Asahi ◽  
K Ubukata ◽  
M Konno
Keyword(s):  
Streptococcus Pneumoniae ◽  
Nucleotide Sequence ◽  
Molecular Mechanism ◽  
Active Site ◽  
Binding Protein ◽  
Direct Repeat ◽  
Penicillin Binding Protein ◽  
Serine Residue ◽  
Class A ◽  
Class B

We investigated the molecular mechanism of 50 penicillin-resistant Streptococcus pneumoniae strains (penicillin: MIC, > or = 0.125 microgram/ml) having neither class A nor class B mutations in the penicillin-binding protein 2B gene (pbp2b). An analysis of the nucleotide sequences of the pbp2b genes from seven strains revealed an unique direct repeat of 9 nucleotides (TGGTATACT) between active-site serine (residue 385) and Ser-X-Asn (residues 442 to 444) motifs. The same insertion was detected in 13 strains.

scholarly journals A Low-Affinity Penicillin-Binding Protein 2x Variant Is Required for Heteroresistance in Streptococcus pneumoniae

2014 ◽  
Vol 58 (7) ◽  
pp. 3934-3941 ◽  
Author(s):  
Hansjürg Engel ◽  
Moana Mika ◽  
Dalia Denapaite ◽  
Regine Hakenbeck ◽  
Kathrin Mühlemann ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Abc Transporter ◽  
Binding Protein ◽  
Population Analysis ◽  
Resistance Testing ◽  
Penicillin Binding Protein ◽  
Secondary Resistance ◽  
Content Type ◽  
Abc Transporter Genes

ABSTRACTHeteroresistance to penicillin inStreptococcus pneumoniaeis the ability of subpopulations to grow at a higher antibiotic concentration than expected from the MIC. This may render conventional resistance testing unreliable and lead to therapeutic failure. We investigated the role of the primary β-lactam resistance determinants, penicillin-binding protein 2b (PBP2b) and PBP2x, and the secondary resistance determinant PBP1a in heteroresistance to penicillin. Transformants containing PBP genes from the heteroresistant strain Spain23F2349in the nonheteroresistant strain R6 background were tested for heteroresistance by population analysis profiling (PAP). We found thatpbp2x, but notpbp2borpbp1aalone, conferred heteroresistance to R6. However, a change ofpbp2xexpression was not observed, and therefore, expression does not correlate with an increased proportion of resistant subpopulations. In addition, the influence of the CiaRH system, mediating PBP-independent β-lactam resistance, was assessed by PAP onciaRdisruption mutants but revealed no heteroresistant phenotype. We also showed that the highly resistant subpopulations (HOM*) of transformants containing low-affinitypbp2xundergo an increase in resistance upon selection on penicillin plates that partially reverts after passaging on selection-free medium. Shotgun proteomic analysis showed an upregulation of phosphate ABC transporter subunit proteins encoded bypstS,phoU,pstB, andpstCin these highly resistant subpopulations. In conclusion, the presence of low-affinitypbp2xenables certain pneumococcal colonies to survive in the presence of β-lactams. Upregulation of phosphate ABC transporter genes may represent a reversible adaptation to antibiotic stress.

scholarly journals Identification and Characterization of the Penicillin-Binding Protein 2a of Streptococcus pneumoniae and Its Possible Role in Resistance to β-Lactam Antibiotics

2000 ◽  
Vol 44 (6) ◽  
pp. 1745-1748 ◽  
Author(s):  
Genshi Zhao ◽  
Timothy I. Meier ◽  
Joann Hoskins ◽  
Kelly A. McAllister
Keyword(s):  
Streptococcus Pneumoniae ◽  
Binding Protein ◽  
Penicillin Resistance ◽  
Penicillin Binding Protein ◽  
Insertional Mutant ◽  
Identification And Characterization

ABSTRACT To further understand the role of penicillin-binding protein 2a (PBP 2a) of Streptococcus pneumoniae in penicillin resistance, we confirmed the identity of the protein as PBP 2a. The PBP 2a protein migrated electrophoretically to a position corresponding to that of PBP 2x, PBP 2a, and PBP 2b of S. pneumoniae and was absent in a pbp2ainsertional mutant of S. pneumoniae. We found that the affinities of PBP 2a for penicillins were lower than for cephalosporins and a carbapenem. When compared with other S. pneumoniae PBPs, PBP 2a exhibited lower affinities for β-lactam antibiotics, especially penicillins. Therefore, PBP 2a is a low-affinity PBP for β-lactam antibiotics in S. pneumoniae.

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