scholarly journals Identification and Detection ofStenotrophomonas maltophilia by rRNA-Directed PCR

2000 ◽  
Vol 38 (12) ◽  
pp. 4305-4309 ◽  
Author(s):  
Paul W. Whitby ◽  
Karen B. Carter ◽  
Jane L. Burns ◽  
James A. Royall ◽  
John J. LiPuma ◽  
...  

Stenotrophomonas maltophilia has recently emerged as an important nosocomial pathogen in immunocompromised patients, in transplant recipients, and in persons with cystic fibrosis (CF). While this organism is nonpathogenic in healthy individuals, it is increasingly associated with morbidity and mortality in susceptible populations. Recent studies have indicated that for approximately 10% of CF patients with moderate lung disease, S. maltophiliacan be cultured from respiratory tract secretions. Identification ofS. maltophilia can be problematic, and analysis of isolates from the Burkholderia cepacia Research Laboratory and Repository showed that several isolates presumptively identified asB. cepacia by clinical microbiology laboratories were in fact S. maltophilia. To overcome the problems associated with definitive identification, we developed species-specific PCR (SS-PCR) primers, designated SM1 and SM4, directed to the 23S rRNA gene, and tested their utility to accurately identify S. maltophilia directly from sputum. The SS-PCR was developed and tested against a panel of 112 S. maltophilia isolates collected from diverse geographic locations. To test for specificity, 43 isolates from 17 different species were analyzed. PCR with the SM1-SM4 primer pair and isolated genomic DNA as a template resulted in amplification of a band from all S. maltophilia isolates and was uniformly negative for all other species tested, yielding a sensitivity and a specificity of 100% for the SS-PCR. The utility of the SS-PCR to directly identify S. maltophilia in sputum was examined. Thirteen expectorated sputum samples from CF patients were analyzed by SS-PCR. Three samples were PCR positive, in complete concordance with the conventional laboratory culture. Thus, we have developed an SS-PCR protocol that can rapidly and accurately identifyS. maltophilia isolates and which can be used for the direct detection of this organism in CF patient sputum.

2007 ◽  
Vol 57 (11) ◽  
pp. 2636-2644 ◽  
Author(s):  
G. Douglas Inglis ◽  
Bryanne M. Hoar ◽  
Douglas P. Whiteside ◽  
Douglas W. Morck

Ten isolates of an unknown Campylobacter species were isolated from cloacal swabs obtained from captive adult whooping cranes (Grus americana). All isolates were identified as Campylobacter based on generic PCR and grouped with other Campylobacter species based on 23S rRNA gene sequence. None of the isolates could be identified by species-specific PCR for known taxa, and all ten isolates formed a robust clade that was very distinct from known Campylobacter species based on 16S rRNA, rpoB and cpn60 gene sequences. The results of 16S rRNA gene nucleotide sequence (≤92 % sequence similarity to recognized Campylobacter species) and genomic DNA (no detectable relatedness) analyses were consistent with novel species status. Cells of the Campylobacter from whooping cranes were uniflagellar and typically sigmoid to allantoid in shape (0.48 μm wide and 2.61 μm long), but also spheroid to coccoid (0.59 μm wide and 0.73 μm long). The bacterium was oxidase-positive, able to reduce nitrite, able to grow at 3 ° and 42 °C, and grew anaerobically, as well as in an atmosphere devoid of H2, and on MacConkey agar. It was not α-haemolytic and was negative for hippurate and indoxyl acetate hydrolysis and alkaline phosphatase. It also was susceptible to cephalotin and was unable to grow on nutrient agar, on a medium containing 3.5 % NaCl or in ambient O2. The bacterium was unable to grow at 25 °C and growth was negative or very restricted at 30 °C. Fluorescent amplified fragment length polymorphism analysis indicated that nine of the recovered isolates were genetically distinct. A species-specific primer set targeting the cpn60 gene was developed. The name Campylobacter canadensis sp. nov. is proposed for the novel species, with the type strain L266T (=CCUG 54429T =LMG 24001T).


Author(s):  
Konrad Egli ◽  
Anna Roditscheff ◽  
Ursula Flückiger ◽  
Martin Risch ◽  
Lorenz Risch ◽  
...  

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.


Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 208-214 ◽  
Author(s):  
Lia W. Liefting ◽  
Paul W. Sutherland ◽  
Lisa I. Ward ◽  
Kerry L. Paice ◽  
Bevan S. Weir ◽  
...  

A new disease of glasshouse-grown tomato and pepper in New Zealand has resulted in plant decline and yield loss. Affected plants are characterized by spiky, chlorotic apical growth, curling or cupping of the leaves, and overall stunting. Transmission electron microscopy revealed the presence of phloem-limited bacterium-like organisms in symptomatic plants. The strategy used to identify the bacterium involved using specific prokaryote polymerase chain reaction (PCR) primers in combination with universal 16S rRNA primers. Sequence analysis of the 16S rRNA gene, the 16S/23S rRNA spacer region, and the rplKAJL-rpoBC operon revealed that the bacterium shared high identity with ‘Candidatus Liberibacter’ species. Phylogenetic analysis showed that the bacterium is distinct from the three citrus liberibacter species previously described and has been named ‘Candidatus Liberibacter solanacearum’. This is the first report of a liberibacter naturally infecting a host outside the Rutaceae family. A specific PCR primer pair was developed for its detection.


2000 ◽  
Vol 38 (1) ◽  
pp. 282-285
Author(s):  
Paul W. Whitby ◽  
Lauren C. Pope ◽  
Karen B. Carter ◽  
John J. LiPuma ◽  
Terrence L. Stull

ABSTRACT Burkholderia gladioli colonizes the respiratory tracts of patients with cystic fibrosis and chronic granulomatous disease. However, due to the high degree of phenotypic similarity between this species and closely related species in the Burkholderia cepacia complex, accurate identification is difficult. Incorrect identification of these species may have serious repercussions for the management of patients with cystic fibrosis. To develop an accurate procedure for the identification of B. gladioli , a molecular method to discriminate between this species and other species commonly isolated from the sputa of patients with cystic fibrosis was investigated. The 23S ribosomal DNA was cloned from several clinical isolates of B. gladioli , and the nucleotide sequence was determined. Computer-assisted sequence comparisons indicated four regions of the 23S rRNA specific for this species; these regions were used to design three primer pairs for species-specific PCR. Two of the primer pairs showed 100% sensitivity and specificity for B. gladioli when tested against a panel of 47 isolates comprising 19 B. gladioli isolates and 28 isolates of 16 other bacterial species. One of the primer pairs was further assessed for species specificity by using a panel of 102 isolates obtained from the Burkholderia cepacia Research Laboratory and Repository. The species-specific PCR was positive for 70 of 74 isolates of B. gladioli and was negative for all other bacterial species examined. Overall, this primer pair displayed a sensitivity and specificity of 96% (89 of 93) and 100%, respectively. These data demonstrate the potential of species-specific PCR for the identification of B. gladioli .


2020 ◽  
Author(s):  
Eiseul Kim ◽  
Seung-Min Yang ◽  
Bora Lim ◽  
Si Hong Park ◽  
Bryna Rackerby ◽  
...  

Abstract Background Lactobacillus species are used as probiotics and play an important role in fermented food production. However, use of 16S rRNA gene sequences as standard markers for the differentiation of Lactobacillus species offers a very limited scope, as several species of Lactobacillus share similar 16S rRNA gene sequences. In this study, we developed a rapid and accurate method based on comparative genomic analysis for the simultaneous identification of 37 Lactobacillus species that are commonly used in probiotics and fermented foods. Results To select species-specific sequences or genes, a total of 180 Lactobacillus genome sequences were compared using Python scripts. In 14 out of 37 species, species-specific sequences could not be found due to the similarity of the 16S–23S rRNA gene. Selected unique genes were obtained using comparative genomic analysis and all genes were confirmed to be specific for 52,478,804 genomes via in silico analysis; they were found not to be strain-specific, but to exist in all strains of the same species. Species-specific primer pairs were designed from the selected 16S–23S rRNA gene sequences or unique genes of species. The specificity of the species-specific primer pairs was confirmed using reference strains, and the accuracy and efficiency of the polymerase chain reaction (PCR) with the standard curve were confirmed. The PCR method developed in this study is able to accurately differentiate species that were not distinguishable using the 16S rRNA gene alone. This PCR assays were designed to detect and identify 37 Lactobacillus species. The developed method was then applied in the monitoring of 19 probiotics and 12 dairy products. The applied tests confirmed that the species detected in 17 products matched those indicated on their labels, whereas the remaining products contained species other than those appearing on the label. Conclusions The method developed in this study is able to rapidly and accurately distinguish different species of Lactobacillus , and can be used to monitor specific Lactobacillus species in foods such as probiotics and dairy products.


2003 ◽  
Vol 69 (9) ◽  
pp. 5664-5669 ◽  
Author(s):  
P.S. Lübeck ◽  
P. Wolffs ◽  
S. L. W. On ◽  
P. Ahrens ◽  
P. Rådström ◽  
...  

ABSTRACT As part of a European research project (FOOD-PCR), we developed a standardized and robust PCR detection assay specific for the three most frequently reported food-borne pathogenic Campylobacter species, C. jejuni, C. coli, and C. lari. Fifteen published and unpublished PCR primers targeting the 16S rRNA gene were tested in all possible pairwise combinations, as well as two published primers targeting the 23S rRNA gene. A panel of 150 strains including target and nontarget strains was used in an in-house validation. Only one primer pair, OT1559 plus 18-1, was found to be selective. The inclusivity and exclusivity were 100 and 97%, respectively. In an attempt to find a thermostable DNA polymerase more resistant than Taq to PCR inhibitors present in chicken samples, three DNA polymerases were evaluated. The DNA polymerase Tth was not inhibited at a concentration of 2% (vol/vol) chicken carcass rinse, unlike both Taq DNA polymerase and DyNAzyme. Based on these results, Tth was selected as the most suitable enzyme for the assay. The standardized PCR test described shows potential for use in large-scale screening programs for food-borne Campylobacter species under the assay conditions specified.


2001 ◽  
Vol 67 (7) ◽  
pp. 3195-3200 ◽  
Author(s):  
Fanrong Kong ◽  
Gregory James ◽  
Susanna Gordon ◽  
Anna Zelynski ◽  
Gwendolyn L. Gilbert

ABSTRACT Mycoplasma arginini, M. fermentans, M. hyorhinis, M. orale, and Acholeplasma laidlawii are the members of the class Mollicutes most commonly found in contaminated cell cultures. Previous studies have shown that the published PCR primer pairs designed to detect mollicutes in cell cultures are not entirely specific. The 16S rRNA gene, the 16S-23S rRNA intergenic spacer region, and the 5′ end of the 23S rRNA gene, as a whole, are promising targets for design of mollicute species-specific primer pairs. We analyzed the 16S rRNA genes, the 16S-23S rRNA intergenic spacer regions, and the 5′ end of the 23S rRNA genes of these mollicutes and developed PCR methods for species identification based on these regions. Using high melting temperatures, we developed a rapid-cycle PCR for detection and identification of contaminant mollicutes. Previously published, putative mollicute-specific primers amplified DNA from 73 contaminated cell lines, but the presence of mollicutes was confirmed by species-specific PCR in only 60. Sequences of the remaining 13 amplicons were identified as those of gram-positive bacterial species. Species-specific PCR primers are needed to confirm the presence of mollicutes in specimens and for identification, if required.


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