Related Experiment Videos
Alterations in penicillin binding protein gene of Streptococcus pneumoniae and their correlation with susceptibility
Yoshinobu Ohsaki1, Mineji Tachibana, Kyoko Nakanishi
1First Department of Medicine, Asahikawa Medical College, 2-1-1-1 Midorigaoka Higashi, Asahikawa 078-8510, Hokkaido, Japan. yohsaki@asahikawa-med.ac.jp
Abstract:
Penicillin binding protein (pbp) gene alterations of 328 clinical isolates of Streptococcus pneumoniae were examined for a correlation with their antibiotic-resistance. The frequency of penicillin G (PEN-G) resistance was determined to clarify susceptibility to several antibiotics, namely PEN-G, ampicillin, sulbactam/ampicillin, cefozopram, panipenem (PAPM), clarithromycin (CLR), azithromycin (AZM) and levofloxacin (LVX). Oligonucleotide primers for three pbp genes (pbp1a, pbp2x and pbp2b) were used to detect mutations in pbp. Of the strains, 25.9% were classified as Pen-Gs, 68.0% as Pen-Gir and 6.1% as Pen-Gr. The polymerase chain reaction product for wild-type pbp1a was found in 185 isolates, that for wild-type pbp2x was found in 66 isolates and that for wild-type pbp2b was found in 213 isolates. None of these three genes was detectable in 100 isolates while all of them were detected in 64 isolates (1aw/2xw/2bw). Of those 64 isolates with 1aw/2xw/2bw, the minimum inhibitory concentration (MIC) of PEN-G was < or =0.06 mg/l for 54 isolates and 0.12 mg/l for 10 isolates. Of the 272 strains for which the MIC of PAPM was < or =0.03 mg/l, there were 85 Pen-Gs, 184 Pen-Gir and three Pen-Gr isolates. Three strains for which the MIC of LVX was > or =4.0 mg/l included one Pen-Gs and two Pen-Gir isolates. The MICs of CLR correlated significantly with those of AZM. The MIC of CLR was > or =1 mg/l for 216 isolates, and the MIC of AZM was > or =1 mg/l for 244 of them. These data suggested that PAPM may be effective against S. pneumoniae infection, although acquisition of resistance should be considered. LVX also seemed to be effective against S. pneumoniae.
Insights
Penicillin binding protein (pbp) gene mutations in Streptococcus pneumoniae correlate with antibiotic resistance. Panipenem and levofloxacin show potential effectiveness against S. pneumoniae infections, though resistance monitoring is crucial.
Area of Science:
- Microbiology
- Molecular Biology
- Pharmacology
Background:
- Streptococcus pneumoniae is a leading cause of bacterial infections.
- Antibiotic resistance in S. pneumoniae is a growing public health concern.
- Penicillin binding proteins (PBPs) are key targets for antibiotics like penicillin.
Purpose of the Study:
- To investigate the correlation between penicillin binding protein (pbp) gene alterations and antibiotic resistance in clinical isolates of Streptococcus pneumoniae.
- To determine the susceptibility of S. pneumoniae isolates to various antibiotics, including penicillin G, ampicillin, panipenem, clarithromycin, azithromycin, and levofloxacin.
Main Methods:
- Analysis of penicillin binding protein (pbp) gene alterations (pbp1a, pbp2x, pbp2b) using oligonucleotide primers and polymerase chain reaction (PCR).
- Determination of minimum inhibitory concentrations (MICs) for various antibiotics against 328 clinical isolates of S. pneumoniae.
- Classification of isolates based on penicillin G (PEN-G) resistance levels: Pen-Gs, Pen-Gir, and Pen-Gr.
Main Results:
- Prevalence of penicillin G resistance was observed in 25.9% (Pen-Gs), 68.0% (Pen-Gir), and 6.1% (Pen-Gr) of isolates.
- Mutations in pbp1a, pbp2x, and pbp2b genes were detected with varying frequencies.
- Panipenem (PAPM) showed potential efficacy, with most strains exhibiting low MICs.
- Levofloxacin (LVX) also appeared effective against S. pneumoniae.
- Significant correlation was found between clarithromycin (CLR) and azithromycin (AZM) resistance.
Conclusions:
- Penicillin binding protein gene alterations are associated with antibiotic resistance in Streptococcus pneumoniae.
- Panipenem and levofloxacin demonstrate promising activity against S. pneumoniae, warranting further investigation.
- Continuous monitoring for the emergence of antibiotic resistance is essential for effective treatment strategies.