22 results on '"Rajanna C"'
Search Results
2. The Vibrio pathogenicity island of epidemic Vibrio cholerae forms precise extrachromosomal circular excision products
- Author
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Rajanna, C., Wang, J., Zhang, D., Xu, Zheng, Ali, A., Hou, Y.-M., and Karaolis, D.K.R
- Subjects
Bacteriology -- Research ,Chromosomes -- Genetic aspects ,DNA -- Genetic aspects ,Microbial populations -- Genetic aspects ,Nucleotide sequence -- Genetic aspects ,Pathogenic microorganisms -- Genetic aspects ,Pathogenic microorganisms -- Physiological aspects ,Polymerase chain reaction -- Analysis ,Transfer RNA -- Genetic aspects ,Vibrio -- Genetic aspects ,Vibrio -- Physiological aspects ,Virulence (Microbiology) -- Genetic aspects ,Biological sciences - Abstract
The Vibrio pathogenicity island (VPI) in epidemic Vibrio cholerae is an essential virulence gene cluster. Like many pathogenicity islands, the VPI has at its termini a phage-like integrase gene (int), a transposase-like gene (vpiT), and phage-like attachment (att) sites, and is inserted at a tRNA-like locus (ssrA). We report that the VPI precisely excises from the chromosome and that its left and right ends join to form an extrachromosomal circular excision product (pVPI). Two-stage nested PCR analysis and DNA sequencing confirmed the int-att-vpiT junction and that the core attP of pVPI is identical to the chromosomal VPI attR site. Excision was independent of toxR and toxT. Excision was independent of recA, suggesting that it is mediated by site-specific recombination. Interestingly, while excision was detected in int and vpiT mutants, excision was abolished in a double (int vpiT) mutant and was restored by plasmids containing genes for either recombinase. Excision results in deletion of A361 in the ssrA locus, which flanks the right junction of the VPI. Since A361 encodes U70 in the critical G * U base pair in the acceptor stem of the ssrA RNA that is the determinant for aminoacylation with alanine, this deletion might have deleterious effects on ssrA function. Also, vpiT may have undergone interchromosomal translocation or may represent an independent integration event, as it was found downstream of hutA in some isolates. Our results provide new insight into the molecular biology of the VPI, and we propose that the process of excision and circularization is important in the emergence, pathogenesis, and persistence of epidemic V. cholerae. more...
- Published
- 2003
Catalog
3. Effect of Different Organic Manures on Growth and Survival of Carps Rearing from Fry to Fingerlings.
- Author
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Rajanna C., Shivakumar M., and H., Shivananda Murthy
- Published
- 2021
4. EFFECT OF ORGANIC MANURES ON PLANKTON PRODUCTION.
- Author
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Rajanna, C., Shivakumar, M., and Murthy, H. Shivananda
- Subjects
PLANKTON ,FOOD chains ,AUTOTROPHS ,POULTRY manure - Abstract
In an aquatic ecosystem, understanding food chain or food web is very important to understand the production and productivity. Phytoplankton are autotrophs and primary producers and make the basis for all energy production in the entire food web. In this research, the influence of manures on rate of production of phytoplankton is studied. Four commonly used manures like poultry manure (PM), cowdung (CD) and combination of cow dung with poultry manure (PM+CD) and control (no manure) were compared. It was also correlated with the physicochemical parameters. The dominant phytoplankton species in all the treatments were Pediastrum, Chlorella, Eudorina, Closterium, Anabena and Microcysits etc. Poultry manure stimulated the highest plankton production followed by combination of poultry and cowdung while the least was with cowdung and control (no manure). The mean values for temperature were 27.4°C for PM, 27.1°C for CD and 27.3°C for the CD+PM. pH was 8.0 in CD treatment, 8.38 in PM treatment, 8.16 in CD+PM. Dissolved oxygen was 6.0 mg/l throughout the culture systems. Ammonia recorded 1.31 mg/l for poultry manure, 0.5 mg/l for cowdung and 0.74 mg/l was recorded in cowdung + poultry manure. T3 (CD+PM) produced the highest number of phytoplankton 986/ml in the third week and the level was maintained higher than other two treatments during the experiment period where the high plankton number in T1 was 852 No./ml in 4th week and in T2, the highest was 820 No./ml, which was noticed in 6th week. The nitrate and phosphates level was high in T2 271.69 mg/l in poultry manure, in cowdung it was 63.63 mg/l and 135.62 mg/l in cowdung + poultry manure. This moderate level of N and P induced high average plankton in T3 (4.92 ml/100 L), followed by T1 (4.22 ml/100 L) and T2 (3.83 ml/100 L). There was a mixed result in this experiment. It is discussed in detail in the conclusion with a comparison among survival per cent, growth rate and economics. ANOVA results showed significant differences (P<0.05) in phytoplankton production between Poultry manure, cowdung and cowdung + poultry manure. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
5. Rapid Detection and Simultaneous Antibiotic Susceptibility Analysis of Yersinia pestis Directly from Clinical Specimens by Use of Reporter Phage
- Author
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Vandamm, J. P., primary, Rajanna, C., additional, Sharp, N. J., additional, Molineux, I. J., additional, and Schofield, D. A., additional
- Published
- 2014
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6. Rapid Detection and Simultaneous Antibiotic Susceptibility Analysis of Yersinia pestisDirectly from Clinical Specimens by Use of Reporter Phage
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Vandamm, J. P., Rajanna, C., Sharp, N. J., Molineux, I. J., and Schofield, D. A.
- Abstract
ABSTRACTYersinia pestisis a tier 1 agent due to its contagious pneumopathogenicity, extremely rapid progression, and high mortality rate. As the disease is usually fatal without appropriate therapy, rapid detection from clinical matrices is critical to patient outcomes. We previously engineered the diagnostic phage FA1122 with luxABto create a “light-tagged” reporter phage. FA1122::luxABrapidly detects Y. pestisin pure culture and human serum by transducing a bioluminescent signal response. In this report, we assessed the analytical specificity of the reporter phage and investigated diagnostic utility (detection and antibiotic susceptibility analysis) directly from spiked whole blood. The bioreporter displayed 100% (n= 59) inclusivity for Y. pestisand consistent intraspecific signal transduction levels. False positives were not obtained from species typically associated with bacteremia or those relevant to plague diagnosis. However, some non-pestis Yersiniastrains and Enterobacteriaceaedid elicit signals, albeit at highly attenuated transduction levels. Diagnostic performance was assayed in simple broth-enriched blood samples and standard aerobic culture bottles. In blood, <102CFU/ml was detected within 5 h. In addition, Y. pestiswas identified directly from positive blood cultures within 20 to 45 min without further processing. Importantly, coincubation of blood samples with antibiotics facilitated simultaneous antimicrobial susceptibility profiling. Consequently, the reporter phage demonstrated rapid detection and antibiotic susceptibility profiling directly from clinical samples, features that may improve patient prognosis during plague outbreaks. more...
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- 2014
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7. A study on the morbid histopathological changes in COVID-19 patients with or without comorbidities using minimally invasive tissue sampling.
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Goel A, Ray A, Chavan A, Sahni S, Gupta BK, Raut SK, Agarwal S, Nehra J, Somu B, Raja R, Aakansha, Nagpal C, Rajanna C, Shahi A, Rajendran A, Varadrajan A, Hasan I, Choppala P, Priyadarshi M, Jain D, Subramanian A, Arava S, Singh G, Das P, Sarkar C, Nischal N, Soneja M, Jorwal P, Trikha A, and Wig N more...
- Subjects
- Humans, SARS-CoV-2, Lung pathology, Heart, COVID-19 pathology, Thrombosis
- Abstract
COVID-19 causes morbid pathological changes in different organs including lungs, kidneys, liver, and so on, especially in those who succumb. Though clinical outcomes in those with comorbidities are known to be different from those without-not much is known about the differences at the histopathological level. To compare the morbid histopathological changes in COVID-19 patients between those who were immunocompromised (Gr 1), had a malignancy (Gr 2), or had cardiometabolic conditions (hypertension, diabetes, or coronary artery disease) (Gr 3), postmortem tissue sampling (minimally invasive tissue sampling [MITS]) was done from the lungs, kidney, heart, and liver using a biopsy gun within 2 hours of death. Routine (hematoxylin and eosin) and special staining (acid fast bacilli, silver methanamine, periodic acid schiff) was done besides immunohistochemistry. A total of 100 patients underwent MITS and data of 92 patients were included (immunocompromised: 27, malignancy: 18, cardiometabolic conditions: 71). In lung histopathology, capillary congestion was more in those with malignancy, while others like diffuse alveolar damage, microthrombi, pneumocyte hyperplasia, and so on, were equally distributed. In liver histopathology, architectural distortion was significantly different in immunocompromised; while steatosis, portal inflammation, Kupffer cell hypertrophy, and confluent necrosis were equally distributed. There was a trend towards higher acute tubular injury in those with cardiometabolic conditions as compared to the other groups. No significant histopathological difference in the heart was discerned. Certain histopathological features were markedly different in different groups (Gr 1, 2, and 3) of COVID-19 patients with fatal outcomes., (© 2022 Wiley Periodicals LLC.) more...
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- 2023
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8. Novel Scoring Systems to Predict the Need for Oxygenation and ICU Care, and Mortality in Hospitalized COVID-19 Patients: A Risk Stratification Tool.
- Author
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Keri VC, Jorwal P, Verma R, Ranjan P, Upadhyay AD, Aggarwal A, Sarda R, Sharma K, Sahni S, and Rajanna C
- Abstract
Introduction: A rapid surge in cases during the COVID-19 pandemic can overwhelm any healthcare system. It is imperative to triage patients who would require oxygen and ICU care, and predict mortality. Specific parameters at admission may help in identifying them., Methodology: A prospective observational study was undertaken in a COVID-19 ward of a tertiary care center. All baseline clinical and laboratory data were captured. Patients were followed till death or discharge. Univariable and multivariable logistic regression was used to find predictors of the need for oxygen, need for ICU care, and mortality. Objective scoring systems were developed for the same using the predictors., Results: The study included 209 patients. Disease severity was mild, moderate, and severe in 98 (46.9%), 74 (35.4%), and 37 (17.7%) patients, respectively. The neutrophil-to-lymphocyte ratio (NLR) >4 was a common independent predictor of the need for oxygen (p<0.001), need for ICU transfer (p=0.04), and mortality (p=0.06). Clinical risk scores were developed (10*c-reactive protein (CRP) + 14.8*NLR + 12*urea), (10*aspartate transaminase (AST) + 15.7*NLR + 14.28*CRP), (10*NLR + 10.1*creatinine) which, if ≥14.8, ≥25.7, ≥10.1 predicted need for oxygenation, need for ICU transfer and mortality with a sensitivity and specificity (81.6%, 70%), (73.3%, 75.7%), (61.1%, 75%), respectively. Conclusion: The NLR, CRP, urea, creatinine, and AST are independent predictors in identifying patients with poor outcomes. An objective scoring system can be used at the bedside for appropriate triaging of patients and utilization of resources., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Keri et al.) more...
- Published
- 2022
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9. Post COVID-19 sequelae: A prospective observational study from Northern India.
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Naik S, Haldar SN, Soneja M, Mundadan NG, Garg P, Mittal A, Desai D, Trilangi PK, Chakraborty S, Begam NN, Bhattacharya B, Maher G, Mahishi N, Rajanna C, Kumar SS, Arunan B, Kirtana J, Gupta A, Patidar D, Kodan P, Sethi P, Ray A, Jorwal P, Kumar A, Nischal N, Sinha S, Biswas A, and Wig N more...
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- Adolescent, Adult, Aged, Aged, 80 and over, COVID-19 epidemiology, COVID-19 etiology, COVID-19 pathology, Cough epidemiology, Cough etiology, Dyspnea epidemiology, Dyspnea etiology, Fatigue epidemiology, Fatigue etiology, Female, Humans, India epidemiology, Male, Middle Aged, Myalgia epidemiology, Myalgia etiology, Prospective Studies, Risk Factors, Sleep Initiation and Maintenance Disorders epidemiology, Sleep Initiation and Maintenance Disorders etiology, Young Adult, Post-Acute COVID-19 Syndrome, COVID-19 complications
- Abstract
Post COVID-19 sequelae are a constellation of symptoms often reported after recovering from COVID-19. There is a need to better understand the clinical spectrum and long-term course of this clinical entity. The aim of this study is to describe the clinical features and risk factors of post COVID-19 sequelae in the North Indian population. This prospective observational study was conducted at a tertiary healthcare centre in Northern India between October 2020 and February 2021. Patients aged >18 years with laboratory-confirmed COVID-19 were recruited after at least two weeks of diagnosis, and details were captured. A total of 1234 patients were recruited and followed up for a median duration of 91 days (IQR: 45-181 days). Among them, 495 (40.1%) had persistent symptoms post-discharge or recovery. In 223 (18.1%) patients, the symptoms resolved within four weeks; 150 (12.1%) patients had symptoms till 12 weeks, and 122 (9.9%) patients had symptoms beyond 12 weeks of diagnosis/symptom-onset of COVID-19. Most common symptoms included myalgia (10.9%), fatigue (5.5%), shortness of breath (6.1%), cough (2.1%), insomnia (1.4%), mood disturbances (0.48%) and anxiety (0.6%). Patients who were hospitalized were more likely to report fatigue as a feature of long COVID. Hypothyroidism (OR: 4.13, 95% CI: 2.2-7.6, p-value < 0.001) and hypoxia (SpO
2 ≤ 93%) (OR: 1.7, 95% CI: 1.1-2.4, p-value 0.012) were identified as risk factors for long COVID sequelae. In conclusion, long COVID symptoms were common (22%), and 9.9% had the post COVID-19 syndrome. Myalgias, fatigue and dyspnoea were common symptoms. Patients with hypothyroidism and hypoxia during acute illness were at higher risk of long COVID. more...- Published
- 2021
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10. When sitting suffocates: a rare cause of platypnoea-orthodeoxia syndrome.
- Author
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Nema R, Rajanna C, Ray A, Jadon RS, and Vikram NK
- Abstract
Platypnoea-orthodeoxia syndrome refers to shortness of breath and oxygen desaturation in an upright position. Ventilation/perfusion mismatch is a rare cause of the same. Herein, we report a case of bilateral lower lobe tuberculosis, causing platypnoea and orthodeoxia. https://bit.ly/3jhJEQ1., Competing Interests: Conflict of interest: R. Nema has nothing to disclose. Conflict of interest: C. Rajanna has nothing to disclose. Conflict of interest: A. Ray has nothing to disclose. Conflict of interest: R.S. Jadon has nothing to disclose. Conflict of interest: N.K. Vikram has nothing to disclose., (Copyright ©ERS 2021.) more...
- Published
- 2020
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11. Scanning the landscape of genome architecture of non-O1 and non-O139 Vibrio cholerae by whole genome mapping reveals extensive population genetic diversity.
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Chapman C, Henry M, Bishop-Lilly KA, Awosika J, Briska A, Ptashkin RN, Wagner T, Rajanna C, Tsang H, Johnson SL, Mokashi VP, Chain PS, and Sozhamannan S
- Subjects
- Chromosomes, Bacterial genetics, DNA, Bacterial genetics, Electrophoresis, Gel, Pulsed-Field, Gene Duplication, Gene Rearrangement genetics, Genome Size, INDEL Mutation genetics, Phylogeny, Reproducibility of Results, Restriction Mapping, Sequence Analysis, DNA, Chromosome Mapping methods, Genetic Variation, Genome, Bacterial, Vibrio cholerae genetics
- Abstract
Historically, cholera outbreaks have been linked to V. cholerae O1 serogroup strains or its derivatives of the O37 and O139 serogroups. A genomic study on the 2010 Haiti cholera outbreak strains highlighted the putative role of non O1/non-O139 V. cholerae in causing cholera and the lack of genomic sequences of such strains from around the world. Here we address these gaps by scanning a global collection of V. cholerae strains as a first step towards understanding the population genetic diversity and epidemic potential of non O1/non-O139 strains. Whole Genome Mapping (Optical Mapping) based bar coding produces a high resolution, ordered restriction map, depicting a complete view of the unique chromosomal architecture of an organism. To assess the genomic diversity of non-O1/non-O139 V. cholerae, we applied a Whole Genome Mapping strategy on a well-defined and geographically and temporally diverse strain collection, the Sakazaki serogroup type strains. Whole Genome Map data on 91 of the 206 serogroup type strains support the hypothesis that V. cholerae has an unprecedented genetic and genomic structural diversity. Interestingly, we discovered chromosomal fusions in two unusual strains that possess a single chromosome instead of the two chromosomes usually found in V. cholerae. We also found pervasive chromosomal rearrangements such as duplications and indels in many strains. The majority of Vibrio genome sequences currently in public databases are unfinished draft sequences. The Whole Genome Mapping approach presented here enables rapid screening of large strain collections to capture genomic complexities that would not have been otherwise revealed by unfinished draft genome sequencing and thus aids in assembling and finishing draft sequences of complex genomes. Furthermore, Whole Genome Mapping allows for prediction of novel V. cholerae non-O1/non-O139 strains that may have the potential to cause future cholera outbreaks. more...
- Published
- 2015
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12. Bacillus anthracis diagnostic detection and rapid antibiotic susceptibility determination using 'bioluminescent' reporter phage.
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Schofield DA, Sharp NJ, Vandamm J, Molineux IJ, Spreng KA, Rajanna C, Westwater C, and Stewart GC
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- Bacillus cereus isolation & purification, Bacteriophages genetics, Humans, Species Specificity, Bacillus anthracis drug effects, Bacillus anthracis isolation & purification, Drug Resistance, Bacterial, Genes, Reporter, Luminescent Measurements methods
- Abstract
Genetically modified phages have the potential to detect pathogenic bacteria from clinical, environmental, or food-related sources. Herein we assess an engineered 'bioluminescent' reporter phage (Wß::luxAB) as a clinical diagnostic tool for Bacillus anthracis, the etiological agent of anthrax. Wß::luxAB is able to rapidly (within minutes) detect a panel of B. anthracis strains by transducing a bioluminescent phenotype. The reporter phage displays species specificity by its inability, or significantly reduced ability, to detect members of the closely related Bacillus cereus group and other common bacterial pathogens. Using spiked clinical specimens, Wß::luxAB detects B. anthracis within 5 h at clinically relevant concentrations, and provides antibiotic susceptibility information that mirrors the CLSI method, except that data are obtained at least 5-fold faster. Although anthrax is a treatable disease, a positive patient prognosis is dependent on timely diagnosis and appropriate therapy. Wß::luxAB rapidly detects B. anthracis and determines antibiotic efficacy, properties that will help patient outcome., (© 2013.) more...
- Published
- 2013
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13. A strain of Yersinia pestis with a mutator phenotype from the Republic of Georgia.
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Rajanna C, Ouellette G, Rashid M, Zemla A, Karavis M, Zhou C, Revazishvili T, Redmond B, McNew L, Bakanidze L, Imnadze P, Rivers B, Skowronski EW, O'Connell KP, Sulakvelidze A, and Gibbons HS
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- Alleles, Amino Acid Sequence, Bacterial Proteins genetics, Bacterial Proteins metabolism, Base Sequence, Chromosome Mapping, Gene Expression, Genetic Complementation Test, Genome, Bacterial, Georgia (Republic), Molecular Sequence Data, Polymorphism, Single Nucleotide, Sequence Alignment, Yersinia pestis isolation & purification, Mutation, Phenotype, Yersinia pestis genetics, Yersinia pestis metabolism
- Abstract
We describe here a strain of Yersinia pestis, G1670A, which exhibits a baseline mutation rate elevated 250-fold over wild-type Y. pestis. The responsible mutation, a C to T substitution in the mutS gene, results in the transition of a highly conserved leucine at position 689 to arginine (mutS(L689R)). When the MutSL 689R protein of G1670A was expressed in a ΔmutS derivative of Y. pestis strain EV76, mutation rates observed were equivalent to those observed in G1670A, consistent with a causal association between the mutS mutation and the mutator phenotype. The observation of a mutator allele in Yersinia pestis has potential implications for the study of evolution of this and other especially dangerous pathogens., (© 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.) more...
- Published
- 2013
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14. Genome Sequence of Non-O1 Vibrio cholerae PS15.
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Kumar S, Lindquist IE, Sundararajan A, Rajanna C, Floyd JT, Smith KP, Andersen JL, He G, Ayers RM, Johnson JA, Werdann JJ, Sandoval AA, Mojica NM, Schilkey FD, Mudge J, and Varela MF
- Abstract
The draft genome sequence of a non-O1 Vibrio cholerae strain, PS15, organized into 3,512 open reading frames within a 3.9-Mb genome, was determined. The PS15 genome sequence will allow for the study of the evolution of virulence and environmental adaptation in V. cholerae. more...
- Published
- 2013
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15. A Yersinia pestis-specific, lytic phage preparation significantly reduces viable Y. pestis on various hard surfaces experimentally contaminated with the bacterium.
- Author
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Rashid MH, Revazishvili T, Dean T, Butani A, Verratti K, Bishop-Lilly KA, Sozhamannan S, Sulakvelidze A, and Rajanna C
- Abstract
Five Y. pestis bacteriophages obtained from various sources were characterized to determine their biological properties, including their taxonomic classification, host range and genomic diversity. Four of the phages (YpP-G, Y, R and YpsP-G) belong to the Podoviridae family, and the fifth phage (YpsP-PST) belongs to the Myoviridae family, of the order Caudovirales comprising of double-stranded DNA phages. The genomes of the four Podoviridae phages were fully sequenced and found to be almost identical to each other and to those of two previously characterized Y. pestis phages Yepe2 and φA1122. However, despite their genomic homogeneity, they varied in their ability to lyse Y. pestis and Y. pseudotuberculosis strains. The five phages were combined to yield a "phage cocktail" (tentatively designated "YPP-100") capable of lysing the 59 Y. pestis strains in our collection. YPP-100 was examined for its ability to decontaminate three different hard surfaces (glass, gypsum board and stainless steel) experimentally contaminated with a mixture of three genetically diverse Y. pestis strains CO92, KIM and 1670G. Five minutes of exposure to YPP-100 preparations containing phage concentrations of ca. 10(9), 10(8) and 10(7) PFU/mL completely eliminated all viable Y. pestis cells from all three surfaces, but a few viable cells were recovered from the stainless steel coupons treated with YPP-100 diluted to contain ca. 10(6) PFU/mL. However, even that highly diluted preparation significantly (p = < 0.05) reduced Y. pestis levels by ≥ 99.97%. Our data support the idea that Y. pestis phages may be useful for decontaminating various hard surfaces naturally- or intentionally-contaminated with Y. pestis. more...
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- 2012
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16. Enumeration of bacteriophage particles: Comparative analysis of the traditional plaque assay and real-time QPCR- and nanosight-based assays.
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Anderson B, Rashid MH, Carter C, Pasternack G, Rajanna C, Revazishvili T, Dean T, Senecal A, and Sulakvelidze A
- Abstract
Bacteriophages are increasingly being utilized and considered for various practical applications, ranging from decontaminating foods and inanimate surfaces to human therapy; therefore, it is important to determine their concentrations quickly and reliably. Traditional plaque assay (PA) is the current "gold standard" for quantitating phage titers. However, it requires at least 18 h before results are obtained, and they may be significantly influenced by various factors. Therefore, two alternative assays based on the quantitative real-time polymerase chain reaction (QPCR) and NanoSight Limited (NS) technologies were recently proposed for enumerating phage particles. The present study compared the three approaches' abilities to quantitate Listeria monocytogenes-, Escherichia coli O157:H7- and Yersinia pestis-specific lytic phages quickly and reproducibly. The average coefficient of variation (CVS) of the PA method including all three phages was 0.15. The reproducibility of the PA method decreased dramatically when multiple investigators performed the assays, and mean differences of as much as 0.33 log were observed. The QPC R method required costly equipment and the synthesis of phage-specific oligonucleotide primers, but it determined phage concentrations faster (within about 4 h) and more precisely than did PA (CVS = 0.13). NS technology required costly equipment, was less precise (CVS = 0.28) than the PA and QPCR methods, and only worked when the phages were suspended in clear medium. However, it provided results within 5 min. After the overall correlation is established with the PA method, either of the two assays may be useful for quickly and reproducibly determining phage concentrations. more...
- Published
- 2011
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17. Characterization of pPCP1 Plasmids in Yersinia pestis Strains Isolated from the Former Soviet Union.
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Rajanna C, Revazishvili T, Rashid MH, Chubinidze S, Bakanidze L, Tsanava S, Imnadze P, Bishop-Lilly KA, Sozhamannan S, Gibbons HS, Morris JG, and Sulakvelidze A
- Abstract
Complete sequences of 9.5-kb pPCP1 plasmids in three Yersinia pestis strains from the former Soviet Union (FSU) were determined and compared with those of pPCP1 plasmids in three well-characterized, non-FSU Y. pestis strains (KIM, CO92, and 91001). Two of the FSU plasmids were from strains C2614 and C2944, isolated from plague foci in Russia, and one plasmid was from strain C790 from Kyrgyzstan. Sequence analyses identified four sequence types among the six plasmids. The pPCP1 plasmids in the FSU strains were most genetically related to the pPCP1 plasmid in the KIM strain and least related to the pPCP1 plasmid in Y. pestis 91001. The FSU strains generally had larger pPCP1 plasmid copy numbers compared to strain CO92. Expression of the plasmid's pla gene was significantly (P ≤ .05) higher in strain C2944 than in strain CO92. Given pla's role in Y. pestis virulence, this difference may have important implications for the strain's virulence. more...
- Published
- 2010
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18. Genetic background and antibiotic resistance of Staphylococcus aureus strains isolated in the Republic of Georgia.
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Revazishvili T, Bakanidze L, Gomelauri T, Zhgenti E, Chanturia G, Kekelidze M, Rajanna C, Kreger A, and Sulakvelidze A
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- Georgia (Republic) epidemiology, Humans, Phylogeny, Staphylococcal Infections epidemiology, Staphylococcal Infections microbiology, Anti-Bacterial Agents pharmacology, Drug Resistance, Multiple, Bacterial, Staphylococcus aureus drug effects, Staphylococcus aureus genetics
- Abstract
The genetic composition and antibiotic sensitivities of 50 clinical isolates of Staphylococcus aureus obtained from various clinics in the Republic of Georgia were characterized. S. aureus strains ATCC 700699 and ATCC 29737 were included as reference standards in all analyses. All 52 strains had identical 16S rRNA profiles. In contrast, pulsed-field gel electrophoresis (PFGE) identified 20 distinct PFGE types among the 52 strains examined, which indicates that PFGE is more discriminating than is 16S rRNA sequence analysis for differentiating S. aureus strains. The results of our PFGE typing also suggest that multiple genetic subpopulations (related at the ca. 85% similarity level, based on their SmaI PFGE patterns) exist among the Georgian S. aureus strains. Twenty-two of the 50 Georgian strains were methicillin resistant and PCR positive for mecA, and 5 strains were methicillin sensitive even though they possessed mecA. None of the strains were vancomycin resistant or contained vanA. The nucleotide sequences of mecA fragments obtained from all mecA-containing strains were identical. Our data indicate that the population of S. aureus strains in Georgia is fairly homogeneous and that the prevalence of methicillin-resistant, mecA-positive strains is relatively high in that country. more...
- Published
- 2006
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19. Identification and characterization of a novel adhesin unique to oral fusobacteria.
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Han YW, Ikegami A, Rajanna C, Kawsar HI, Zhou Y, Li M, Sojar HT, Genco RJ, Kuramitsu HK, and Deng CX
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- Adhesins, Bacterial chemistry, Adhesins, Bacterial genetics, Amino Acid Sequence, Animals, CHO Cells, Cell Line, Cricetinae, Fusobacterium nucleatum genetics, Fusobacterium nucleatum growth & development, Gene Deletion, Humans, Molecular Sequence Data, Molecular Weight, Mutation, Sequence Alignment, Species Specificity, Adhesins, Bacterial metabolism, Fusobacterium nucleatum metabolism
- Abstract
Fusobacterium nucleatum is a gram-negative anaerobe that is prevalent in periodontal disease and infections of different parts of the body. The organism has remarkable adherence properties, binding to partners ranging from eukaryotic and prokaryotic cells to extracellular macromolecules. Understanding its adherence is important for understanding the pathogenesis of F. nucleatum. In this study, a novel adhesin, FadA (Fusobacterium adhesin A), was demonstrated to bind to the surface proteins of the oral mucosal KB cells. FadA is composed of 129 amino acid (aa) residues, including an 18-aa signal peptide, with calculated molecular masses of 13.6 kDa for the intact form and 12.6 kDa for the secreted form. It is highly conserved among F. nucleatum, Fusobacterium periodonticum, and Fusobacterium simiae, the three most closely related oral species, but is absent in the nonoral species, including Fusobacterium gonidiaformans, Fusobacterium mortiferum, Fusobacterium naviforme, Fusobacterium russii, and Fusobacterium ulcerans. In addition to FadA, F. nucleatum ATCC 25586 and ATCC 49256 also encode two paralogues, FN1529 and FNV2159, each sharing 31% identity with FadA. A double-crossover fadA deletion mutant, F. nucleatum 12230-US1, was constructed by utilizing a novel sonoporation procedure. The mutant had a slightly slower growth rate, yet its binding to KB and Chinese hamster ovarian cells was reduced by 70 to 80% compared to that of the wild type, indicating that FadA plays an important role in fusobacterial colonization in the host. Furthermore, due to its uniqueness to oral Fusobacterium species, fadA may be used as a marker to detect orally related fusobacteria. F. nucleatum isolated from other parts of the body may originate from the oral cavity. more...
- Published
- 2005
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20. Role of exopolysaccharide, the rugose phenotype and VpsR in the pathogenesis of epidemic Vibrio cholerae.
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Rashid MH, Rajanna C, Zhang D, Pasquale V, Magder LS, Ali A, Dumontet S, and Karaolis DK
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- Animals, Animals, Suckling, Bacterial Proteins genetics, Cholera microbiology, Cholera physiopathology, Cholera Toxin biosynthesis, Gene Expression Regulation, Bacterial, Humans, Ileum microbiology, Mice, Phenotype, Polysaccharides, Bacterial genetics, Rabbits, Vibrio cholerae metabolism, Virulence, Bacterial Proteins metabolism, Cholera epidemiology, Disease Outbreaks, Polysaccharides, Bacterial metabolism, Vibrio cholerae pathogenicity, Vibrio cholerae physiology
- Abstract
Vibrio cholerae, the causative agent of cholera can produce an exopolysaccharide (EPS). Some strains can also phenotypically switch from a smooth to a 'rugose' phenotype characterized by small wrinkled colonies, overproduction of EPS, increased biofilm formation in vitro and increased resistance to various stressful conditions. High frequency switching to the rugose phenotype is more common in epidemic strains than in non-pathogenic strains, suggesting EPS production and the rugose phenotype are important in cholera epidemiology. VpsR up-regulates Vibrio polysaccharide (VPS) genes and the synthesis of extracellular EPS (VPS). However, the function of VPS, the rugose phenotype and VpsR in pathogenesis is not well understood. We report that rugose strains of both classical and El Tor biotypes of epidemic V. cholerae are defective in the in vitro production of extracellular collagenase activity. In vivo studies in rabbit ileal loops suggest that VpsR mutants are attenuated in reactogenicity. Intestinal colonization studies in infant mice suggest that VPS production, the rugose phenotype and VpsR have a role in pathogenesis. Our results indicate that regulated VPS production is important for promoting in vivo biofilm formation and pathogenesis. Additionally, VpsR might regulate genes with roles in virulence. Rugose strains appear to be a subpopulation of cells that might act as a 'helper' phenotype promoting the pathogenesis of certain strains. Our studies provide new insight into the potential role of VPS, the rugose phenotype and VpsR in the pathogenesis of epidemic V. cholerae. more...
- Published
- 2004
- Full Text
- View/download PDF
21. Identification of genes involved in the switch between the smooth and rugose phenotypes of Vibrio cholerae.
- Author
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Rashid MH, Rajanna C, Ali A, and Karaolis DK
- Subjects
- DNA Transposable Elements, Genes, Bacterial genetics, Mutagenesis, Insertional, Phenotype, Polysaccharides, Bacterial physiology, Vibrio cholerae classification, Vibrio cholerae genetics, Biofilms, Genes, Bacterial physiology, Polysaccharides, Bacterial metabolism, Vibrio cholerae physiology
- Abstract
Vibrio cholerae can switch to a 'rugose' phenotype characterized by an exopolysaccharide (EPS) matrix, wrinkled colony morphology, increased biofilm formation and increased survival under specific conditions. The vps gene cluster responsible for the biosynthesis of the rugose EPS (rEPS) is positively regulated by VpsR. We recently identified media (APW#3) promoting EPS production and the rugose phenotype and found epidemic strains switch at a higher frequency than non-pathogenic strains, suggesting this switch and the rugose phenotype are important in cholera epidemiology. In this study, transposon mutagenesis on a smooth V. cholerae strain was used to identify mutants that were unable to shift to the rugose phenotype under inducing conditions to better understand the molecular basis of the switch. We identified vpsR, galE and vps previously associated with the rugose phenotype, and also identified genes not previously associated with the phenotype, including rfbD and rfbE having roles in LPS (lipopolysaccharide) synthesis and aroB and aroK with roles in aromatic amino acid synthesis. Additionally, a mutation in amiB encoding N-acetylmuramoyl-L-alanine amidase caused defects in the switch, motility and cell morphology. We also found that a gene encoding a novel regulatory protein we termed RocS (regulation of cell signaling) containing a GGDEF and EAL domains and associated with c-di-GMP levels is important for the rugose phenotype, EPS, biofilm formation and motility. We propose that modulation of cyclic dinucleotide (e.g. c-di-GMP) levels might have application in regulating various phenotypes of prokaryotes. Our study shows the molecular complexity of the switch between the smooth and rugose phenotypes of V. cholerae and may be relevant to similar phenotypes in other species. more...
- Published
- 2003
- Full Text
- View/download PDF
22. Analysis of the Vibrio pathogenicity island-encoded Mop protein suggests a pleiotropic role in the virulence of epidemic Vibrio cholerae.
- Author
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Zhang D, Rajanna C, Sun W, and Karaolis DK
- Subjects
- Animals, Biofilms growth & development, Blotting, Western, Cell Adhesion genetics, Cholera Toxin biosynthesis, Fimbriae Proteins biosynthesis, Gene Expression, Genetic Complementation Test, Hemolysin Proteins biosynthesis, Intestines microbiology, Metalloendopeptidases biosynthesis, Mice, Movement, Mutation, Reverse Transcriptase Polymerase Chain Reaction, Vibrio cholerae physiology, Virulence genetics, Virulence Factors genetics, Virulence Factors metabolism, Metalloendopeptidases genetics, Metalloendopeptidases physiology, Vibrio cholerae genetics, Vibrio cholerae pathogenicity
- Abstract
Epidemic Vibrio cholerae contain a large essential virulence gene cluster called the Vibrio pathogenicity island (VPI). We recently reported that no in vitro difference in virulence was found in El Tor strain N16961 containing a mutation in the VPI-encoded mop gene but this mutant was hypervirulent and reactogenic in rabbit ileal loops. In this paper, we report in vitro studies showing that independent Mop mutants of strain 3083 are significantly attenuated (approximately 40-fold) in cholera toxin (CT) production and have significantly increased motility and biofilm forming ability but appear to be unaffected in TcpA, hemagglutinin protease and hemolysin compared to their parent. The 3083 Mop mutant showed a 100-fold decrease in its in vivo intestinal colonization ability in the infant mouse competition assays. While reverse transcription polymerase chain reaction and phenotypic studies of a mop plasmid in both mutant and wild-type backgrounds suggest Mop is expressed by the plasmid, the differences in CT and biofilm formation could not be restored in any of the mutants. The inability to complement the Mop mutants in trans may be due either to the selection of secondary mutations or to mop possibly being part of an operon. Our findings that Mop is associated with CT, motility, biofilm formation and intestinal colonization support a hypothesis in which Mop has a pleiotropic role in the pathogenesis and persistence of epidemic V. cholerae. more...
- Published
- 2003
- Full Text
- View/download PDF
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