scholarly journals Relationship between Antimicrobial Susceptibility and Multilocus Sequence Type of Mycoplasma bovis Isolates and Development of a Method for Rapid Detection of Point Mutations Involved in Decreased Susceptibility to Macrolides, Lincosamides, Tetracyclines, and Spectinomycin

2019 ◽  
Vol 85 (13) ◽  
Author(s):  
Eiji Hata ◽  
Takehiro Harada ◽  
Megumi Itoh
Keyword(s):  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Point Mutations ◽  
Melting Curve ◽  
Sequence Type ◽  
23S Rrna ◽  
Mycoplasma Bovis ◽  
Rrna Gene ◽  
Content Type ◽  
Transition Mutation

ABSTRACT Mycoplasma bovis isolates belonging to the sequence type 5 (ST5) group, the dominant group in Japan since 1999, were low susceptible to 16-membered macrolides and tetracyclines and were confirmed to have a guanine-to-adenine transition mutation at position 748 in the 23S rRNA gene (rrl) and adenine-to-thymine transversion mutations at positions 965 and 967 in the 16S rRNA gene (rrs) (Escherichia coli numbering). Moreover, isolates of ST93 and ST155, members of the ST5 group, were low susceptible to lincosamides and azithromycin and showed an adenine-to-guanine transition mutation at position 2059 of rrl. Isolates of ST93 were additionally low susceptible to spectinomycin and showed a cytosine-to-adenine transversion mutation at position 1192 of rrs. Strains of the ST5 group seem to spread to Japan and Europe from North America with imported cows, while strains of ST93 and ST155 originated in Japan. Melting curve analysis using hybridization probes revealed the existence of point mutations involved in decreased susceptibility to macrolides, lincosamides, and spectinomycin, as demonstrated by changes in the melting curve shape and/or decreases in the melting peak temperature, so the susceptibility to these antimicrobials can be assessed on the same day. For decreased susceptibility to fluoroquinolones to exist, nonsynonymous mutations in the DNA gyrase gene (gyrA) and topoisomerase IV gene (parC) had to coexist. The combination of amino acid substitutions of serine at position 83 in gyrA and serine at position 80 in parC resulted in particularly low susceptibility to fluoroquinolones. IMPORTANCE Mycoplasma bovis is the main causal species of bovine mycoplasmal disease and leads to significant economic losses because of its severe symptoms, strong infectivity, and refractoriness. As for mastitis, culling cows with intramammary infections is a general countermeasure to prevent spreading. The conventional antimicrobial susceptibility test for mycoplasma is time-consuming and troublesome, but no quick and easy method for grasping the antimicrobial susceptibility of the causal strain exists at present. Treatment without antimicrobial susceptibility information may be one reason why M. bovis infection is refractory. Detecting a mutation involved in decreased susceptibility to antimicrobial agents of the causal strain makes it possible to easily select suitable antimicrobials for treatment, and this technique will help improve the cure rate and prevent the overuse of ineffective antimicrobial agents. In this study, we developed a technique to quickly and easily assess antimicrobial susceptibility based on the genetic characteristics of M. bovis strains in Japan.

scholarly journals Trends towards Lower Antimicrobial Susceptibility and Characterization of Acquired Resistance among Clinical Isolates of Brachyspira hyodysenteriae in Spain

2011 ◽  
Vol 55 (7) ◽  
pp. 3330-3337 ◽  
Author(s):  
Álvaro Hidalgo ◽  
Ana Carvajal ◽  
Birte Vester ◽  
Märit Pringle ◽  
Germán Naharro ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Molecular Mechanisms ◽  
Tandem Repeats ◽  
Point Mutations ◽  
Clinical Isolates ◽  
23S Rrna ◽  
Rrna Gene ◽  
Content Type ◽  
Brachyspira Hyodysenteriae ◽  
23S Rrna Gene

ABSTRACTThe antimicrobial susceptibility of clinical isolates ofBrachyspira hyodysenteriaein Spain was monitored, and the underlying molecular mechanisms of resistance were investigated. MICs of tylosin, tiamulin, valnemulin, lincomycin, and tylvalosin were determined for 87B. hyodysenteriaeisolates recovered from 2008 to 2009 by broth dilution. Domain V of the 23S rRNA gene and the ribosomal protein L3 gene were sequenced in 20 isolates for which the tiamulin MIC was ≥4 μg/ml, presenting decreased susceptibility, and in 18 tiamulin-susceptible isolates (MIC ≤ 0.125 μg/ml), and all isolates were typed by multiple-locus variable-number tandem repeats analysis. A comparison with antimicrobial susceptibility data from 2000 to 2007 showed an increase in pleuromutilin resistance over time, doubling the number of isolates with decreased susceptibility to tiamulin. No alteration in susceptibility was detected for lincomycin, and the MIC of tylosin remained high (MIC50> 128 μg/ml). The decreased susceptibility to tylosin and lincomycin can be explained by mutations at position A2058 of the 23S rRNA gene (Escherichia colinumbering). A2058T was the predominant mutation, but A2058G also was found together with a change of the neighboring base pair at positions 2057 to 2611. The role of additional point mutations in the vicinity of the peptidyl transferase center and mutations in the L3 at amino acids 148 and 149 and their possible involvement in antimicrobial susceptibility are considered. An association between G2032A and high levels of tiamulin and lincomycin MICs was found, suggesting an increasing importance of this mutation in antimicrobial resistance of clinical isolates ofB. hyodysenteriae.

scholarly journals Phenotypic and Molecular Antimicrobial Susceptibility of Helicobacter pylori

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Derrick Chen ◽  
Scott A. Cunningham ◽  
Nicolynn C. Cole ◽  
Peggy C. Kohner ◽  
Jayawant N. Mandrekar ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Point Mutations ◽  
The United States ◽  
23S Rrna ◽  
Rrna Gene ◽  
Content Type ◽  
Clarithromycin Resistance ◽  
23S Rrna Gene ◽  
H Pylori

ABSTRACT Failure to eradicate Helicobacter pylori infection is often a result of antimicrobial resistance, which for clarithromycin is typically mediated by specific point mutations in the 23S rRNA gene. The purpose of this study was to define current patterns of antimicrobial susceptibility in H. pylori isolates derived primarily from the United States and to survey them for the presence of point mutations in the 23S rRNA gene and assess the ability of these mutations to predict phenotypic clarithromycin susceptibility. Antimicrobial susceptibility testing was performed using agar dilution on 413 H. pylori isolates submitted to Mayo Medical Laboratories for susceptibility testing. For a subset of these isolates, a 150-bp segment of the 23S rRNA gene was sequenced. A total of 1,970 MICs were reported over the 4-year study period. The rate of clarithromycin resistance was high (70.4%), and elevated MICs were frequently observed for metronidazole (82.4% of isolates had an MIC of >8 μg/ml) and ciprofloxacin (53.5% of isolates had an MIC of >1 μg/ml). A total of 111 archived H. pylori isolates underwent 23S rRNA gene sequencing; we found 95% concordance between genotypes and phenotypes (P = 0.9802). Resistance to clarithromycin was most commonly due to an A2143G mutation (82%), followed by A2142G (14%) and A2142C (4%) mutations. Clinical H. pylori isolates derived primarily from the United States demonstrated a high rate of clarithromycin resistance and elevated metronidazole and ciprofloxacin MICs. The relative distribution of point mutations at positions 2143 and 2142 in the 23S rRNA gene in clarithromycin-resistant H. pylori was similar to that reported from other parts of the world; these mutations predict phenotypic resistance to clarithromycin.

scholarly journals T2182C Mutation in 23S rRNA Is Associated with Clarithromycin Resistance in Helicobacter pylori Isolates Obtained in Bangladesh

2004 ◽  
Vol 48 (9) ◽  
pp. 3567-3569 ◽  
Author(s):  
Rasel Khan ◽  
Shamsun Nahar ◽  
Jinath Sultana ◽  
Mian Mashhud Ahmad ◽  
Motiur Rahman
Keyword(s):  
Helicobacter Pylori ◽  
Gene Sequence ◽  
Point Mutations ◽  
23S Rrna ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
Clarithromycin Resistance ◽  
Gene Sequence Analysis ◽  
23S Rrna Gene ◽  
Transition Mutation

ABSTRACT Twelve clarithromycin-resistant (MIC, ≥1 μg/ml) Helicobacter pylori isolates were analyzed for point mutations in the 23S rRNA gene. Sequence analysis of all of the resistant isolates revealed a T-to-C transition mutation at position 2182. Transformation experiments confirmed that a single T-to-C transition mutation at position 2182 is associated with clarithromycin resistance.

scholarly journals In VitroActivity of the New Fluoroketolide Solithromycin (CEM-101) against Macrolide-Resistant and -Susceptible Mycoplasma genitalium Strains

2014 ◽  
Vol 58 (6) ◽  
pp. 3151-3156 ◽  
Author(s):  
Jørgen Skov Jensen ◽  
Prabhavathi Fernandes ◽  
Magnus Unemo
Keyword(s):  
Clinical Trials ◽  
Sexually Transmitted Infections ◽  
Antimicrobial Agents ◽  
Mycoplasma Genitalium ◽  
Macrolide Resistance ◽  
23S Rrna ◽  
Rrna Gene ◽  
Content Type ◽  
Sexually Transmitted

ABSTRACTMycoplasma genitaliumhas become well established as an etiological agent of sexually transmitted infections, but due to its fastidious growth requirements, only a fewM. genitaliumstrains are available to determine the MICs of currently used and new antimicrobial agents. Recent clinical trials have suggested that treatment with azithromycin has decreasing efficacy due to an increasing prevalence of macrolide resistance, and alternative treatment with moxifloxacin is similarly under pressure from emerging resistance. Thus, there is an urgent need for new antimicrobials. Thein vitroactivity of the newly developed fluoroketolide solithromycin (CEM-101) was evaluated against a collection of 40M. genitaliumstrains, including 15 with high-level macrolide resistance and 5 multidrug-resistant strains with resistance to both macrolides and quinolones. Furthermore, the MIC of solithromycin was correlated with mutations in the 23S rRNA gene and in the genes encoding ribosomal proteins L4 and L22. Thein vitroresults showed that solithromycin has activity againstM. genitaliumsuperior to that of other macrolides, doxycycline, and fluoroquinolones. Accordingly, this new fluoroketolide might be an effective option for treatment ofM. genitaliuminfections. However, the efficacy of solithromycin in clinical trials with follow-up for test of cure and detection of genotypic and phenotypic resistance needs to be evaluated prior to widespread use. In a phase 2 clinical trial, solithromycin was highly effective as a single oral dose againstC. trachomatisandNeisseria gonorrhoeae, suggesting that solithromycin could be a treatment option for several sexually transmitted infections, including in syndromic treatment of urethral and vaginal discharge.

scholarly journals More Complications Occur in Macrolide-Resistant than in Macrolide-Sensitive Mycoplasma pneumoniae Pneumonia

2013 ◽  
Vol 58 (2) ◽  
pp. 1034-1038 ◽  
Author(s):  
Yunlian Zhou ◽  
Yuanyuan Zhang ◽  
Yuanjian Sheng ◽  
Li Zhang ◽  
Zheng Shen ◽  
...  
Keyword(s):  
Mycoplasma Pneumoniae ◽  
Point Mutations ◽  
Clinical Manifestations ◽  
23S Rrna ◽  
Rrna Gene ◽  
Clinical Issue ◽  
Content Type ◽  
23S Rrna Gene ◽  
The Relationship ◽  
Resistant Genotypes

ABSTRACTWe sought to understand the situation of macrolide-resistant genotypes ofMycoplasma pneumoniae, and analyze the relationship between macrolide-resistant genotypes and clinical manifestations ofMycoplasma pneumoniaepneumonia (MPP). Full-length sequencing of the 23S rRNA gene ofM. pneumoniaewas performed in 235 nasopharyngeal aspirates (NPAs) from children with MPP. We also retrospectively compared the clinical characteristics of macrolide-resistant (MR)M. pneumoniaeinfections and macrolide-sensitive (MS)M. pneumoniaeinfections. A total of 206 patients had point mutations in theM. pneumoniae23S rRNA gene, and these patients are referred to as MR patients. The remaining 29 patients without point mutations are referred to as MS patients. Among 206 MR patients, 199 (96.6%) had A2063G mutations, 6 had A2063T mutations, and the remaining patients had an A2064G mutation. Among the clinical manifestations, we found that the median fever durations were 8 days (range, 0 to 42 days) and 6 days (0 to 14 days) (P< 0.01), the median hospitalization durations were 8 days (2 to 45 days) and 6 days (3 to 16 days) (P< 0.01), and the median fever durations after macrolide therapy were 5 days (0 to 42 days) and 3 days (0 to 10 days) (P< 0.01), respectively, in the MR and MS groups. We also found that the incidence of extrapulmonary complications in the MR group was significantly higher than that in the MS group (P< 0.05). Moreover, the radiological findings were more serious in the MR group than in the MS group (P< 0.05). The increasing prevalence of MRM. pneumoniaehas become a significant clinical issue in the pediatric patients, which may lead to more extrapulmonary complications and severe clinical features and radiological manifestations.

scholarly journals Clinical Characteristics and Treatment Outcomes of Patients with Acquired Macrolide-Resistant Mycobacterium abscessus Lung Disease

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Hayoung Choi ◽  
Su-Young Kim ◽  
Dae Hun Kim ◽  
Hee Jae Huh ◽  
Chang-Seok Ki ◽  
...  
Keyword(s):  
Lung Disease ◽  
Treatment Outcomes ◽  
Point Mutations ◽  
Mycobacterium Abscessus ◽  
Macrolide Resistance ◽  
Clinical Isolates ◽  
23S Rrna ◽  
Molecular Characteristics ◽  
Rrna Gene ◽  
Content Type

ABSTRACT Macrolide antibiotics are mainstays in the treatment of lung disease due to the Mycobacterium abscessus complex. Although previous studies have reported development of acquired macrolide resistance in this species, limited data are available on the outcomes of lung disease due to macrolide-resistant Mycobacterium abscessus subsp. abscessus. This study evaluated the clinical features, treatment outcomes, and molecular characteristics of macrolide-resistant isolates of M. abscessus subsp. abscessus. We performed a retrospective review of medical records and genetic analysis of clinical isolates from 13 patients who had acquired macrolide-resistant M. abscessus subsp. abscessus lung disease between November 2006 and March 2016. Eleven (85%) patients had the nodular bronchiectatic form of the disease, and two (15%) patients had the fibrocavitary form. When acquired macrolide resistance was detected, 10 (77%) patients were on antibiotic therapy for M. abscessus subsp. abscessus, and three (23%) patients were on therapy for lung disease due to other nontuberculous mycobacteria. The median treatment duration after detecting resistance was 24.0 months (interquartile range, 16.0 to 43.0 months). Treatment outcomes were poor, and final sputum culture conversion was achieved in only one (8%) patient, after resectional surgery. All 13 clinical isolates demonstrated point mutations at position 2058 (n = 10) or 2059 (n = 3) of the 23S rRNA gene, which resulted in acquired macrolide resistance. This study indicates that treatment outcomes are very poor after the development of acquired macrolide resistance in patients with M. abscessus subsp. abscessus lung disease. Thus, more effective measures are needed to prevent development and effectively treat macrolide-resistant M. abscessus subsp. abscessus lung disease.

scholarly journals A Novel SimpleProbe PCR Assay for Detection of Mutations in the 23S rRNA Gene Associated with Macrolide Resistance in Mycoplasma genitalium in Clinical Samples

2016 ◽  
Vol 54 (10) ◽  
pp. 2563-2567 ◽  
Author(s):  
Marianne Gossé ◽  
Hilde Lysvand ◽  
Brita Pukstad ◽  
Svein Arne Nordbø
Keyword(s):  
Melting Curve ◽  
Mycoplasma Genitalium ◽  
Curve Analysis ◽  
23S Rrna ◽  
Clinical Samples ◽  
Melting Curve Analysis ◽  
Rrna Gene ◽  
Content Type ◽  
23S Rrna Gene ◽  
Resistant Strains

Macrolide-resistant strains ofMycoplasma genitaliumare an increasing problem throughout the world, and the implementation of a rapid and sensitive assay for mutation detection to guide treatment is needed. Macrolide-resistant strains have been shown to contain base substitutions in positions 2058 and 2059 (Escherichia colinumbering) in region V of the 23S rRNA gene. In this study, we present a SimpleProbe PCR followed by melting curve analysis to differentiate between macrolide-resistant mutants and wild types. The assay was performed on 159Mycoplasma genitalium-positive samples, and the results were compared with DNA sequencing. We also looked at the prevalence of macrolide-resistant strains in a Norwegian population. Of 139 samples characterized successfully by sequencing, 54 (39%) were wild types and 85 (61%) were mutants, consisting of 59 (42%) A2059G, 24 (17%) A2058G, 1 (1%) A2058T, and 1 (1%) A2059C mutation. The melting curve analysis correctly differentiated between wild-type and mutant strains in all cases, but it could not identify the different mutant types. The SimpleProbe PCR proved to be a simple, rapid, and reliable method for the detection of macrolide-resistant isolates ofMycoplasma genitaliumin a clinical setting.

scholarly journals Antimicrobial Susceptibility to Azithromycin among Salmonella enterica Isolates from the United States

2011 ◽  
Vol 55 (9) ◽  
pp. 3985-3989 ◽  
Author(s):  
Maria Sjölund-Karlsson ◽  
Kevin Joyce ◽  
Karen Blickenstaff ◽  
Takiyah Ball ◽  
Jovita Haro ◽  
...  
Keyword(s):  
United States ◽  
Antimicrobial Susceptibility ◽  
Salmonella Enterica ◽  
Antimicrobial Agents ◽  
The United States ◽  
Outcome Data ◽  
Content Type ◽  
Susceptibility Data ◽  
Retail Meat ◽  
Clinical Breakpoints

ABSTRACTDue to emerging resistance to traditional antimicrobial agents, such as ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol, azithromycin is increasingly used for the treatment of invasiveSalmonellainfections. In the present study, 696 isolates of non-TyphiSalmonellacollected from humans, food animals, and retail meats in the United States were investigated for antimicrobial susceptibility to azithromycin. Seventy-twoSalmonella entericaserotype Typhi isolates from humans were also tested. For each isolate, MICs of azithromycin and 15 other antimicrobial agents were determined by broth microdilution. Among the non-TyphiSalmonellaisolates, azithromycin MICs among human isolates ranged from 1 to 32 μg/ml, whereas the MICs among the animal and retail meat isolates ranged from 2 to 16 μg/ml and 4 to 16 μg/ml, respectively. AmongSalmonellaserotype Typhi isolates, the azithromycin MICs ranged from 4 to 16 μg/ml. The highest MIC observed in the present study was 32 μg/ml, and it was detected in three human isolates belonging to serotypes Kentucky, Montevideo, and Paratyphi A. Based on our findings, we propose an epidemiological cutoff value (ECOFF) for wild-typeSalmonellaof ≤16 μg/ml of azithromycin. The susceptibility data provided could be used in combination with clinical outcome data to determine tentative clinical breakpoints for azithromycin andSalmonella enterica.

scholarly journals Antimicrobial Susceptibility of 260Clostridium botulinumType A, B, Ba, and Bf Strains and a NeurotoxigenicClostridium baratiiType F Strain Isolated from California Infant Botulism Patients

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
Jason R. Barash ◽  
Joe B. Castles ◽  
Stephen S. Arnon
Keyword(s):  
Antimicrobial Susceptibility ◽  
Large Bowel ◽  
Botulinum Neurotoxin ◽  
Antimicrobial Agents ◽  
Infectious Complications ◽  
Suspected Sepsis ◽  
Content Type ◽  
Infant Botulism ◽  
Susceptibility Study ◽  
Almost All

ABSTRACTInfant botulism is an infectious intestinal toxemia that results from colonization of the infant large bowel byClostridium botulinum(or rarely, by neurotoxigenicClostridium baratiiorClostridium butyricum), with subsequent intraintestinal production and absorption of botulinum neurotoxin that then produces flaccid paralysis. The disease is often initially misdiagnosed as suspected sepsis or meningitis, diagnoses that require prompt empirical antimicrobial therapy. Antibiotics may also be needed to treat infectious complications of infant botulism, such as pneumonia or urinary tract infection. Clinical evidence suggests (see case report below) that broad-spectrum antibiotics that are eliminated by biliary excretion may cause progression of the patient’s paralysis by lysingC. botulinumvegetative cells in the large bowel lumen, thereby increasing the amount of botulinum neurotoxin available for absorption. The purpose of this antimicrobial susceptibility study was to identify an antimicrobial agent with little or no activity againstC. botulinumthat could be used to treat infant botulism patients initially diagnosed with suspected sepsis or meningitis, or who acquired secondary infections, without lysingC. botulinum. Testing of 12 antimicrobial agents indicated that almost all California infant botulism patient isolates are susceptible to most clinically utilized antibiotics and are also susceptible to newer antibiotics not previously tested against large numbers ofC. botulinumpatient isolates. No antibiotic with little or no activity againstC. botulinumwas identified. These findings reinforce the importance of promptly treating infant botulism patients with human botulism immune globulin (BIG-IV [BabyBIG]).

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