scholarly journals Time-Kill Study of the Activity of Telithromycin against Macrolide-Resistant Streptococcus pneumoniae Isolates with 23S rRNA Mutations and Changes in Ribosomal Proteins L4 and L22

2005 ◽  
Vol 49 (7) ◽  
pp. 3011-3013 ◽  
Author(s):  
Ralf René Reinert ◽  
Adnan Al-Lahham
Keyword(s):  
Streptococcus Pneumoniae ◽  
Ribosomal Proteins ◽  
23S Rrna ◽  
Rrna Gene ◽  
23S Rrna Gene ◽  
Time Kill

ABSTRACT By use of a time-kill methodology, the antipneumococcal activity of telithromycin was determined against macrolide-resistant S. pneumoniae isolates having mutations in the 23S rRNA gene and changes in the ribosomal proteins L4 and L22. Telithromycin had MICs ranging between 0.03 and 0.25 μg/ml and was bactericidal against four of seven strains after 24 h at two times the MIC.

scholarly journals Molecular pathways to high-level azithromycin resistance in Neisseria gonorrhoeae

2021 ◽  
Author(s):  
J G E Laumen ◽  
S S Manoharan-Basil ◽  
E Verhoeven ◽  
S Abdellati ◽  
I De Baetselier ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Ribosomal Proteins ◽  
Efflux Pump ◽  
23S Rrna ◽  
Rrna Gene ◽  
23S Rrna Gene ◽  
Evolution Of Resistance ◽  
High Level ◽  
Azithromycin Resistance ◽  
Level Resistance

Abstract Background The prevalence of azithromycin resistance in Neisseria gonorrhoeae is increasing in numerous populations worldwide. Objectives To characterize the genetic pathways leading to high-level azithromycin resistance. Methods A customized morbidostat was used to subject two N. gonorrhoeae reference strains (WHO-F and WHO-X) to dynamically sustained azithromycin pressure. We tracked stepwise evolution of resistance by whole genome sequencing. Results Within 26 days, all cultures evolved high-level azithromycin resistance. Typically, the first step towards resistance was found in transitory mutations in genes rplD, rplV and rpmH (encoding the ribosomal proteins L4, L22 and L34 respectively), followed by mutations in the MtrCDE-encoded efflux pump and the 23S rRNA gene. Low- to high-level resistance was associated with mutations in the ribosomal proteins and MtrCDE efflux pump. However, high-level resistance was consistently associated with mutations in the 23S ribosomal RNA, mainly the well-known A2059G and C2611T mutations, but also at position A2058G. Conclusions This study enabled us to track previously reported mutations and identify novel mutations in ribosomal proteins (L4, L22 and L34) that may play a role in the genesis of azithromycin resistance in N. gonorrhoeae.

Antimicrobial susceptibility and mechanisms of high-level macrolide resistance in clinical isolates of Moraxella nonliquefaciens

2014 ◽  
Vol 63 (2) ◽  
pp. 242-247 ◽  
Author(s):  
Shotaro Nonaka ◽  
Kosuke Matsuzaki ◽  
Tomoya Kazama ◽  
Hiroyuki Nishiyama ◽  
Yoko Ida ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Ribosomal Proteins ◽  
Macrolide Resistance ◽  
Clinical Isolates ◽  
23S Rrna ◽  
Rrna Gene ◽  
Efflux System ◽  
Strong Activity ◽  
23S Rrna Gene ◽  
High Level

We investigated antimicrobial susceptibility and the molecular mechanism involved in conferring high-level macrolide resistance in 47 clinical isolates of Moraxella nonliquefaciens from Japan. Antimicrobial susceptibility was determined using Etest and agar dilution methods. Thirty-two erythromycin-non-susceptible strains were evaluated for the possibility of clonal spreading, using PFGE. To analyse the mechanism related to macrolide resistance, mutations in the 23S rRNA gene and the ribosomal proteins, and the presence of methylase genes were investigated by PCR and sequencing. The efflux system was examined using appropriate inhibitors. Penicillin, ampicillin, amoxicillin, cefixime, levofloxacin and antimicrobials containing β-lactamase inhibitors showed strong activity against 47 M. nonliquefaciens isolates. Thirty-two (68.1 %) of the 47 isolates showed high-level MICs to macrolides (MIC ≥128 mg l−1) and shared the A2058T mutation in the 23S rRNA gene. The geometric mean MIC to macrolides of A2058T-mutated strains was significantly higher than that of WT strains (P<0.0001). Thirty-two isolates with high-level macrolide MICs clustered into 30 patterns on the basis of the PFGE dendrogram, indicating that the macrolide-resistant strains were not clonal. In contrast, no common mutations of the ribosomal proteins or methylase genes, or overproduction of the efflux system were observed in A2058T-mutated strains. Moreover, of the 47 M. nonliquefaciens strains, 43 (91.5 %) were bro-1 and 4 (8.5 %) were bro-2 positive. Our results suggest that most M. nonliquefaciens clinical isolates show high-level macrolide resistance conferred by the A2058T mutation in the 23S rRNA gene. This study represents the first characterization of M. nonliquefaciens.

scholarly journals Molecular pathways to high-level azithromycin resistance in Neisseria gonorrhoeae

2020 ◽  
Author(s):  
J.G.E. Laumen ◽  
S.S. Manoharan-Basil ◽  
E Verhoeven ◽  
S Abdellati ◽  
I De Baetselier ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Ribosomal Proteins ◽  
Efflux Pump ◽  
23S Rrna ◽  
Rrna Gene ◽  
23S Rrna Gene ◽  
Evolution Of Resistance ◽  
High Level ◽  
Azithromycin Resistance ◽  
Level Resistance

AbstractObjectivesThe prevalence of azithromycin resistance in Neisseria gonorrhoeae is increasing in numerous populations worldwide. The aim of this study was to characterize the genetic pathways leading to high-level azithromycin resistance.MethodsA customized morbidostat was used to subject two N. gonorrhoeae reference strains (WHO-F and WHO-X) to dynamically sustained azithromycin pressure. We tracked stepwise evolution of resistance by whole genome sequencing.ResultsWithin 26 days, all cultures evolved high-level azithromycin resistance. Typically, the first step towards resistance was found in transitory mutations in genes rplD, rplV and rpmH (encoding the ribosomal proteins L4, L22 and L34 respectively), followed by mutations in the MtrCDE-encoded efflux pump and the 23S rRNA gene. Low-to high-level resistance was associated with mutations in the ribosomal proteins and MtrCDE-encoded efflux pump. However, high-level resistance was consistently associated with mutations in the 23S ribosomal RNA - mainly the well-known A2059G and C2611T mutations, but also at position A2058G.ConclusionsThis study enabled us to track previously reported mutations and identify novel mutations in ribosomal proteins (L4, L22 and L34) that may play a role in the genesis of azithromycin resistance in N. gonorrhoeae.

scholarly journals Mutational and Transcriptomic Changes Involved in the Development of Macrolide Resistance in Campylobacter jejuni

2012 ◽  
Vol 57 (3) ◽  
pp. 1369-1378 ◽  
Author(s):  
Haihong Hao ◽  
Zonghui Yuan ◽  
Zhangqi Shen ◽  
Jing Han ◽  
Orhan Sahin ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Dna Microarray ◽  
Ribosomal Proteins ◽  
Macrolide Resistance ◽  
23S Rrna ◽  
Rrna Gene ◽  
Content Type ◽  
23S Rrna Gene ◽  
Resistant Mutants ◽  
Antibiotic Efflux

ABSTRACTMacrolide antibiotics are important for clinical treatment of infections caused byCampylobacter jejuni. Development of resistance to this class of antibiotics inCampylobacteris a complex process, and the dynamic molecular changes involved in this process remain poorly defined. Multiple lineages of macrolide-resistant mutants were selected by stepwise exposure ofC. jejunito escalating doses of erythromycin or tylosin. Mutations in target genes were determined by DNA sequencing, and the dynamic changes in the expression of antibiotic efflux transporters and the transcriptome ofC. jejuniwere examined by real-time reverse transcription-PCR, immunoblotting, and DNA microarray analysis. Multiple types of mutations in ribosomal proteins L4 and L22 occurred early during stepwise selection. On the contrary, the mutations in the 23S rRNA gene, mediating high resistance to macrolides, were observed only in the late-stage mutants. Upregulation of antibiotic efflux genes was observed in the intermediately resistant mutants, and the magnitude of upregulation declined with the occurrence of mutations in the 23S rRNA gene. DNA microarray analysis revealed the differential expression of 265 genes, most of which occurred in the intermediate mutant, including the upregulation of genes encoding ribosomal proteins and the downregulation of genes involved in energy metabolism and motility. These results indicate (i) that mutations in L4 and L22 along with temporal overexpression of antibiotic efflux genes precede and may facilitate the development of high-level macrolide resistance and (ii) that the development of macrolide resistance affects the pathways important for physiology and metabolism inC. jejuni, providing an explanation for the reduced fitness of macrolide-resistantCampylobacter.

scholarly journals Investigation of Macrolide Resistance Genotypes in Mycoplasma bovis Isolates from Canadian Feedlot Cattle

Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 622 ◽  
Author(s):  
Andrea Kinnear ◽  
Tim A. McAllister ◽  
Rahat Zaheer ◽  
Matthew Waldner ◽  
Antonio C. Ruzzini ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Feedlot Cattle ◽  
23S Rrna ◽  
Dilution Method ◽  
Mycoplasma Bovis ◽  
Rrna Gene ◽  
Single Mutation ◽  
E Coli ◽  
23S Rrna Gene ◽  
Chronic Pneumonia

Mycoplasma bovis is associated with bovine respiratory disease (BRD) and chronic pneumonia and polyarthritis syndrome (CPPS) in feedlot cattle. No efficacious vaccines for M. bovis exist; hence, macrolides are commonly used to control mycoplasmosis. Whole genome sequences of 126 M. bovis isolates, derived from 96 feedlot cattle over 12 production years, were determined. Antimicrobial susceptibility testing (AST) of five macrolides (gamithromycin, tildipirosin, tilmicosin, tulathromycin, tylosin) was conducted using a microbroth dilution method. The AST phenotypes were compared to the genotypes generated for 23S rRNA and the L4 and L22 ribosomal proteins. Mutations in domains II (nucleotide 748; E. coli numbering) and V (nucleotide 2059 and 2060) of the 23S rRNA (rrl) gene alleles were associated with resistance. All isolates with a single mutation at Δ748 were susceptible to tulathromycin, but resistant to tilmicosin and tildipirosin. Isolates with mutations in both domain II and V (Δ748Δ2059 or Δ748Δ2060) were resistant to all five macrolides. However, >99% of isolates were resistant to tildipirosin and tilmicosin, regardless of the number and positions of the mutations. Isolates with a Δ748 mutation in the 23S rRNA gene and mutations in L4 and L22 were resistant to all macrolides except for tulathromycin.

scholarly journals Characterization and Molecular Analysis of Macrolide-Resistant Mycoplasma pneumoniae Clinical Isolates Obtained in Japan

2004 ◽  
Vol 48 (12) ◽  
pp. 4624-4630 ◽  
Author(s):  
Mayumi Matsuoka ◽  
Mitsuo Narita ◽  
Norio Okazaki ◽  
Hitomi Ohya ◽  
Tsutomu Yamazaki ◽  
...  
Keyword(s):  
Mycoplasma Pneumoniae ◽  
Ribosomal Proteins ◽  
Respiratory Infections ◽  
Point Mutations ◽  
23S Rrna ◽  
Nucleotide Sequencing ◽  
Rrna Gene ◽  
Pcr Products ◽  
23S Rrna Gene ◽  
Domain V

ABSTRACT In recent years, Mycoplasma pneumoniae strains that are clinically resistant to macrolide antibiotics have occasionally been encountered in Japan. Of 76 strains of M. pneumoniae isolated in three different areas in Japan during 2000 to 2003, 13 strains were erythromycin (ERY) resistant. Of these 13 strains, 12 were highly ERY resistant (MIC, ≥256 μg/ml) and 1 was weakly resistant (MIC, 8 μg/ml). Nucleotide sequencing of domains II and V of 23S rRNA and ribosomal proteins L4 and L22, which are associated with ERY resistance, showed that 10 strains had an A-to-G transition at position 2063 (corresponding to 2058 in Escherichia coli numbering), 1 strain showed A-to-C transversion at position 2063, 1 strain showed an A-to-G transition at position 2064, and the weakly ERY-resistant strain showed C-to-G transversion at position 2617 (corresponding to 2611 in E. coli numbering) of domain V. Domain II and ribosomal proteins L4 and L22 were not involved in the ERY resistance of these clinical M. pneumoniae strains. In addition, by using our established restriction fragment length polymorphism technique to detect point mutations of PCR products for domain V of the 23S rRNA gene of M. pneumoniae, we found that 23 (24%) of 94 PCR-positive oral samples taken from children with respiratory infections showed A2063G mutation. These results suggest that ERY-resistant M. pneumoniae infection is not unusual in Japan.

scholarly journals Novel Ribosomal Mutations in Staphylococcus aureus Strains Identified through Selection with the Oxazolidinones Linezolid and Torezolid (TR-700)

2009 ◽  
Vol 53 (12) ◽  
pp. 5265-5274 ◽  
Author(s):  
Jeffrey B. Locke ◽  
Mark Hilgers ◽  
Karen Joy Shaw
Keyword(s):  
Staphylococcus Aureus ◽  
Ribosomal Proteins ◽  
Spontaneous Mutation ◽  
Gene Mutations ◽  
Serial Passage ◽  
23S Rrna ◽  
Rrna Gene ◽  
Genes Encoding ◽  
23S Rrna Gene ◽  
Domain V

ABSTRACT TR-700 (torezolid), the active moiety of the novel oxazolidinone phosphate prodrug TR-701, is highly potent against gram-positive pathogens, including strains resistant to linezolid (LZD). Here we investigated the potential of Staphylococcus aureus strains ATCC 29213 (methicillin-susceptible S. aureus [MSSA]) and ATCC 33591 (methicillin-resistant S. aureus [MRSA]) to develop resistance to TR-700. The spontaneous frequencies of mutation of MSSA 29213 and MRSA 33591 resulting in reduced susceptibility to TR-700 at 2× the MIC were 1.1 × 10−10 and 1.9 × 10−10, respectively. These values are ∼16-fold lower than the corresponding LZD spontaneous mutation frequencies of both strains. Following 30 serial passages in the presence of TR-700, the MIC for MSSA 29213 remained constant (0.5 μg/ml) while increasing eightfold (0.25 to 2.0 μg/ml) for MRSA 33591. Serial passage of MSSA 29213 and MRSA 33591 in LZD resulted in 64- and 32-fold increases in LZD resistance (2 to 128 μg/ml and 1 to 32 μg/ml, respectively). Domain V 23S rRNA gene mutations (Escherichia coli numbering) found in TR-700-selected mutants included T2500A and a novel coupled T2571C/G2576T mutation, while LZD-selected mutants included G2447T, T2500A, and G2576T. We also identified mutations correlating with decreased susceptibility to TR-700 and LZD in the rplC and rplD genes, encoding the 50S ribosomal proteins L3 and L4, respectively. L3 mutations included Gly152Asp, Gly155Arg, Gly155Arg/Met169Leu, and ΔPhe127-His146. The only L4 mutation detected was Lys68Gln. TR-700 maintained a fourfold or greater potency advantage over LZD against all strains with ribosomal mutations. These data bring to light a variety of novel and less-characterized mutations associated with S. aureus resistance to oxazolidinones and demonstrate the low resistance potential of torezolid.

scholarly journals Molecular characterization of a ceftriaxone-resistant Neisseria gonorrhoeae strain found in Switzerland: a case report

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Konrad Egli ◽  
Anna Roditscheff ◽  
Ursula Flückiger ◽  
Martin Risch ◽  
Lorenz Risch ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
23S Rrna ◽  
Rrna Gene ◽  
Limited Information ◽  
Specific Pcr ◽  
Appropriate Treatment ◽  
23S Rrna Gene ◽  
Allele Type ◽  
Ciprofloxacin Resistance

Abstract Background The resistance of Neisseria gonorrhoeae to ceftriaxone is unusual in Switzerland. The underlying genotype responsible for resistance is suspected to be novel. Generally, resistance in Neisseria gonorrhoeae (Ng) involves a comprehensive set of genes with many different mutations leading to resistance to different β-lactams and fluoroquinolones. Case presentation A patient had a positive result from specific PCR for Ng. We routinely culture all clinical specimens with a positive NG-PCR. In this particular case, we isolated a strain with resistance to ceftriaxone in Switzerland. A total of seven different genes (penA, ponA, porinB, mtr, gyrA, parC, 23S rRNA gene) in this strain were partially sequenced for comparison with phenotypic susceptibility testing. Interestingly, two different mutations in the porinB gene were observed, and data on this gene are limited. Information on the identified allele type of the penA gene is very limited as well. Three different mutations of parC and gyrA that correlate with ciprofloxacin resistance were found. The combination of ceftriaxone and ciprofloxacin resistance makes an appropriate treatment difficult to obtain due to multidrug resistance. Conclusion The combined results for all genes show the appearance of new mutations in central Europe either due to worldwide spread or the emergence of new genetic combinations of mutations.

scholarly journals Antimicrobial Resistance Profiles and Macrolide Resistance Mechanisms of Campylobacter coli Isolated from Pigs and Chickens

2021 ◽  
Vol 9 (5) ◽  
pp. 1077
Author(s):  
Ji-Hyun Choi ◽  
Dong Chan Moon ◽  
Abraham Fikru Mechesso ◽  
Hee Young Kang ◽  
Su-Jeong Kim ◽  
...  
Keyword(s):  
Nalidixic Acid ◽  
Ribosomal Proteins ◽  
Resistance Mechanisms ◽  
23S Rrna ◽  
Considerable Proportion ◽  
Rrna Gene ◽  
Campylobacter Coli ◽  
Erythromycin Resistance ◽  
Public Health Hazards ◽  
Resistance Rates

We identified 1218 Campylobacter coli isolates from fecal and carcass samples of pigs (n = 643) and chickens (n = 575) between 2010 and 2018. About 99% of the isolates were resistant to at least one antimicrobial agent. The isolates exhibited high resistance rates (>75%) to ciprofloxacin, nalidixic acid, and tetracycline. Azithromycin and erythromycin resistance rates were the highest in isolates from pigs (39.7% and 39.2%, respectively) compared to those of chickens (15.8% and 16.3%, respectively). Additionally, a low-to-moderate proportion of the isolates were resistant to florfenicol, gentamicin, clindamycin, and telithromycin. Multidrug resistance (MDR) was found in 83.1% of the isolates, and profiles of MDR usually included ciprofloxacin, nalidixic acid, and tetracycline. We found point mutation (A2075G) in domain V of the 23S rRNA gene in the majority of erythromycin-resistant isolates. Multilocus sequence typing of 137 erythromycin-resistant C. coli isolates revealed 37 previously reported sequence types (STs) and 8 novel STs. M192I, A103VI, and G74A substitutions were frequently noted in the ribosomal proteins L4 or L22. Further, we identified a considerable proportion (>90%) of erythromycin-resistant isolates carrying virulence factor genes: flaA, cadF, ceuE, and VirB. The prudent use of antimicrobials and regular microbiological investigation in food animals will be vital in limiting the public health hazards of C. coli in Korea.

scholarly journals Molecular Basis of Macrolide Resistance inCampylobacterStrains Isolated from Poultry in South Korea

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Bai Wei ◽  
Min Kang
Keyword(s):  
Molecular Mechanisms ◽  
Macrolide Resistance ◽  
23S Rrna ◽  
Rrna Gene ◽  
Campylobacter Coli ◽  
Erythromycin Resistance ◽  
23S Rrna Gene ◽  
Ribosomal Protein L22 ◽  
Resistant Strains ◽  
Azithromycin Resistance

We investigated the molecular mechanisms underlying macrolide resistance in 38 strains ofCampylobacterisolated from poultry. Twenty-seven strains were resistant to azithromycin and erythromycin, five showed intermediate azithromycin resistance and erythromycin susceptibility, and six showed azithromycin resistance and erythromycin susceptibility. FourCampylobacter jejuniand sixCampylobacter colistrains had azithromycin MICs which were 8–16 and 2–8-fold greater than those of erythromycin, respectively. The A2075G mutation in the 23S rRNA gene was detected in 11 resistant strains with MICs ranging from 64 to ≥ 512μg/mL. Mutations including V137A, V137S, and a six-amino acid insertion (114-VAKKAP-115) in ribosomal protein L22 were detected in theC. jejunistrains. Erythromycin ribosome methylase B-erm(B) was not detected in any strain. All strains except three showed increased susceptibility to erythromycin with twofold to 256-fold MIC change in the presence of phenylalanine arginine ß-naphthylamide (PAßN); the effects of PAßN on azithromycin MICs were limited in comparison to those on erythromycin MICs, and 13 strains showed no azithromycin MIC change in the presence of PAßN. Differences between azithromycin and erythromycin resistance and macrolide resistance phenotypes and genotypes were observed even in highly resistant strains. Further studies are required to better understand macrolide resistance inCampylobacter.

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