INTERACTION OF VIRULENCE GENES IN USTILAGO HORDEI

1976 ◽  
Vol 18 (1) ◽  
pp. 141-149 ◽  
Author(s):  
P. L. Thomas
Keyword(s):  
Virulence Genes ◽  
Single Gene ◽  
Virulence Gene ◽  
Ustilago Hordei ◽  
Genotype V

The genetic cause of virulence of Ustilago hordei on the cultivars Lion and Plush was attributed to a single gene, designated v6. This gene was recessive and unlinked to either v1 or v2. Dikaryons with the genotype v1v1V6v6 were virulent on Hannchen while those with v2v2V6v6 were virulent on Excelsior. However, the the combination v1v1v6v6 was required for virulence on Vantage. The resistance of other cultivars of the host was overcome by combinations of more than one virulence gene in the pathogen, indicating that some cultivars possess more than one gene for resistance.

Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

2020 ◽  
Vol 139 ◽  
pp. 153-160
Author(s):  
S Peeralil ◽  
TC Joseph ◽  
V Murugadas ◽  
PG Akhilnath ◽  
VN Sreejith ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Genes ◽  
Vibrio Harveyi ◽  
Penaeus Monodon ◽  
Challenge Test ◽  
Virulence Gene ◽  
Economic Losses ◽  
Virulence Gene Expression

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

scholarly journals Distribution of virulence genes and SCCmec types among methicillin-resistant Staphylococcus aureus of clinical and environmental origin: a study from community of Assam, India

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Deepshikha Bhowmik ◽  
Shiela Chetri ◽  
Bhaskar Jyoti Das ◽  
Debadatta Dhar Chanda ◽  
Amitabha Bhattacharjee
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Genes ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Virulence Gene ◽  
Type I ◽  
Methicillin Resistant ◽  
Type Iv ◽  
Clinical Community ◽  
Type V ◽  
Sccmec Types

Abstract Objective This study was designed to discover the dissemination of virulence genes in Methicillin-resistant Staphylococcus aureus from clinical, community and environmental settings. Results This study includes 1165 isolates collected from hospital, community and environmental settings. Among them sixty three were confirmed as MRSA with varied SCCmec types viz; type I, type II, type III, type IV, type V, type VI, type VII, type VIII and type XII. The virulence gene such as sea (n = 54), seb (n = 21), eta (n = 27), etb (n = 2), cna (n = 24), ica (n = 2) and tst (n = 30) was also revealed from this study. The study underscores coexistence of resistance cassette and virulence genes among clinical and environment isolates which is first of its kind from this part of the world.

scholarly journals Carbapenem-Resistant Pseudomonas aeruginosa Strains-Distribution of the Essential Enzymatic Virulence Factors Genes

Antibiotics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 8
Author(s):  
Tomasz Bogiel ◽  
Małgorzata Prażyńska ◽  
Joanna Kwiecińska-Piróg ◽  
Agnieszka Mikucka ◽  
Eugenia Gospodarek-Komkowska
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Alkaline Protease ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Hospital Environment ◽  
Gene Encoding ◽  
Virulence Gene Expression ◽  
Carbapenem Resistant ◽  
Antimicrobial Resistance Genes ◽  
The Difference

Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with increasing isolation frequency in nosocomial infections. Herein, we investigated whether antimicrobial-resistant P. aeruginosa strains, e.g., metallo-beta-lactamase (MBL)-producing isolates, may possess a reduced number of virulence genes, resulting from appropriate genome management to adapt to a changing hospital environment. Hospital conditions, such as selective pressure, may lead to the replacement of virulence genes by antimicrobial resistance genes that are crucial to survive under current conditions. The study aimed to compare, using PCR, the frequency of the chosen enzymatic virulence factor genes (alkaline protease-aprA, elastase B-lasB, neuraminidases-nan1 and nan2, and both variants of phospholipase C-plcH and plcN) to MBL distribution among 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. The gene encoding alkaline protease was noted with the highest frequency (100%), while the neuraminidase-1 gene was observed in 37.4% of the examined strains. The difference in lasB and nan1 prevalence amongst the MBL-positive and MBL-negative strains, was statistically significant. Although P. aeruginosa virulence is generally more likely determined by the complex regulation of the virulence gene expression, herein, we found differences in the prevalence of various virulence genes in MBL-producers.

scholarly journals Molecular characteristics and virulence gene profiles of Staphylococcus aureus isolates in Hainan, China

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xuehan Li ◽  
Tao Huang ◽  
Kai Xu ◽  
Chenglin Li ◽  
Yirong Li
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Mainland China ◽  
Geographical Location ◽  
Antibiotic Resistance Genes ◽  
Virulence Gene ◽  
Molecular Characteristics ◽  
Staphylococcal Protein A

Abstract Background There have been no reports regarding the molecular characteristics, virulence features, and antibiotic resistance profiles of Staphylococcus aureus (S. aureus) from Hainan, the southernmost province of China. Methods Two hundred twenty-seven S. aureus isolates, consisting of 76 methicillin-resistant S. aureus (MRSA) and 151 methicillin-susceptible S. aureus (MSSA), were collected in 2013–2014 and 2018–2019 in Hainan, and investigated for their molecular characteristics, virulence genes, antibiotic resistance profiles and main antibiotic resistance genes. Results Forty sequence types (STs) including three new STs (ST5489, ST5492 and ST5493), and 79 Staphylococcal protein A (spa) types were identified based on multilocus sequence typing (MLST) and spa typing, respectively. ST398 (14.1%, 32/227) was found to be the most prevalent, and the prevalence of ST398-MSSA increased significantly from 2013 to 2014 (5.5%, 5/91) to 2018–2019 (18.4%, 25/136). Seventy-six MRSA isolates were subject to staphylococcus chromosomal cassette mec (SCCmec) typing. SCCmec-IVa was the predominant SCCmec type, and specifically, ST45-SCCmec IVa, an infrequent type in mainland China, was predominant in S. aureus from Hainan. The antibiotic resistance profiles and antibiotic resistance genes of S. aureus show distinctive features in Hainan. The resistant rates of the MRSA isolates to a variety of antibiotics were significantly higher than those of the MSSA isolates. The predominant erythromycin and tetracycline resistance genes were ermC (90.1%, 100/111) and tetK (91.8%, 78/85), respectively. Eleven virulence genes, including the Panton-Valentine leukocidin (pvl) and eta, were determined, and the frequency of eta and pvl were found to be 57.3 and 47.6%. Such high prevalence has never been seen in mainland China before. Conclusion S. aureus isolates in Hainan have unique molecular characteristics, virulence gene and antibiotic resistance profiles, and main antibiotic resistance genes which may be associated with the special geographical location of Hainan and local trends in antibiotic use.

Serological diversity, molecular characterisation and antimicrobial sensitivity of avian pathogenic Escherichia coli (APEC) isolates from broiler chickens in Kashmir, India

2019 ◽  
Vol 59 (2) ◽  
pp. 338
Author(s):  
S. N. Magray ◽  
S. A. Wani ◽  
Z. A. Kashoo ◽  
M. A. Bhat ◽  
S. Adil ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Broiler Chickens ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Gene Profile ◽  
Avian Pathogenic Escherichia Coli ◽  
Pathogenic Escherichia Coli ◽  
Significant Difference ◽  
Virulence Gene Profile

The present study has determined the serological diversity, virulence-gene profile and in vitro antibiogram of avian pathogenic Escherichia coli (APEC) isolates from broiler chickens in India suspected to have died of colibacillosis. The virulence-gene profile of APEC was compared with that of the Escherichia coli isolates from faeces of apparently healthy chickens, called avian faecal E. coli (AFEC). In total, 90 representative isolates of APEC and 63 isolates of AFEC were investigated in the present study. The APEC were typed into 19 serogroups, while some isolates were rough and could not be typed. Most prevalent serogroup was O2 (24.44%). Among the eight virulence genes studied, the prevalence of seven genes (iss, iucD, tsh, cva/cvi, irp2, papC and vat) was significantly higher in APEC than in AFEC isolates. However, there was no significant difference between APEC and AFEC isolates for possession of astA gene. The most frequent gene detected among the two groups of organisms was iss, which was present in 98.88% and 44.44% of APEC and AFEC isolates respectively. The in vitro antibiogram showed that the majority (96.6%) of APEC isolates were resistant to tetracycline, while 82.2% were resistant to cephalexin, 78.8% to cotrimoxazole, 68.8% to streptomycin and 63.3% to ampicillin. However, most of them (84.45%) were sensitive to gentamicin. Thus, it is concluded that APEC from the broiler chickens carried putative virulence genes that attributed to their pathogenicity. Furthermore, the majority of APEC isolates were found to be multi-drug resistant, which, in addition to leading treatment failures in poultry, poses a public health threat.

Detection of virulence genes of APEC (avian pathogenic Escherichia coli) isolated from poultry in Noakhali, Bangladesh

2021 ◽  
Vol 7 (1) ◽  
pp. 967-972
Author(s):  
Farzana Ehetasum Hossain ◽  
Saiful Islam ◽  
Md Aminul Islam ◽  
Shariful Islam ◽  
Firoz Ahmed
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Economic Loss ◽  
Point Of View ◽  
Pcr Analysis ◽  
Avian Pathogenic Escherichia Coli ◽  
Gene Profiles ◽  
Pathogenic Escherichia Coli ◽  
Wide Range

Avian colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is one of the major infectious diseases of poultry that bring about great economic loss for the Bangladesh poultry industry. The present study aimed to determine the virulence genes of avian pathogenic Escherichia coli (APEC) from cases of colibacillosis in poultry at the Noakhali district of Bangladesh. Currently, virulence-associated gene profiles of APEC isolates were investigated by polymerase chain reaction (PCR). A total of 24 (twenty-four) Escherichia coli isolates were collected and presumptively identified from 8 (eight) colibacillosis cases from 4 commercial broiler poultry farms (2 broilers per farm) in Noakhali, Bangladesh. The pathogenesis of Escherichia coli involves a wide range of different virulence genes. At this point, four virulence genes, iutA, hlyF, iroN, and iss were detected by PCR analysis. It has been observed that iutA, iss, hlyF, and iroN genes were found in 7(29.16%), 20(83.33%), 22(91.66%), and 24(100%) APEC isolates respectively. Furthermore, out of the twenty-four APEC isolates, six (25%) isolates had four virulence genes, fourteen (58.33%) isolates carried at least three virulence genes, three (12.5%) isolates carried two genes and one (4.16%) isolates had one virulence gene. Most importantly. six types of virulence gene profiles existed within the APEC isolates from which profile number 3 (hlyF, iroN, iss) having 13 (54.16%) isolates were predominant. The occurrence of APEC isolates of this region which is responsible for avian colibacillosis cases can be a matter of concern from the public health point of view. Future investigations will be able to utilize these virulence genes to identify APEC in Bangladesh helping in the diagnosis and prevention of colibacillosis in poultry. Bioresearch Commu. 7(1): 967-972, 2021 (January)

scholarly journals An In-Vitro Study of Molecular Effects of a Combination Treat-ment with Antibiotics and Nanofluid Containing Carbon Nano-tubes on Klebsiella pneumoniae

2021 ◽  
Author(s):  
Maryam Mehdizadeh ◽  
Mojgan Sheikhpour ◽  
Iman Salahshourifar ◽  
Seyed Davar Siadat ◽  
Parvaneh Saffarian
Keyword(s):  
Klebsiella Pneumoniae ◽  
Virulence Genes ◽  
Ultrasonic Method ◽  
Virulence Gene ◽  
In Vitro Study ◽  
Negative Control ◽  
Resistant Isolate ◽  
Simultaneous Treatment ◽  
Virulence Gene Expression

Background: We aimed to prepare a nanofluid, containing f-MWCNTs, and investigate the antibacterial efficacy of f-MWCNTs+ ciprofloxacin (cip) on Klebsiella pneumoniae by evaluating the virulence gene expression. Methods: This study was carried out from 2019 to 2020, in the Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran. The nanofluid containing antibiotic and f-MWCNTs were prepared by the ultrasonic method. The minimum inhibitory concentrations (MICs) of ciprofloxacin and f-MWCNTs were determined using the broth micro dilution MIC tests. For examining the antibacterial effects, the expression level of virulence genes, under the influence of f-MWCNTs, was evaluated by a real-time PCR. Results: The effect of 8 µg/ml ciprofloxacin + 400 µg/ml f-MWCNTs, completely inhibited the growth of the resistant isolate of K. pneumoniae, while, in the ATCC 700,603 isolate, 2 µg/ml ciprofloxacin with 100 µg/ml f-MWCNT could inhibit a bacterial growth. In the resistant K. pneumoniae clinical isolate, after f-MWCNT+cip treatment, the expression of fimA, fimD, wza, and wzi genes was significantly downregulated, compared to the ciprofloxacin treatment, and upregulated, compared to the negative control. For the ATCC 700,603 isolate treated with f-MWCNT+cip, the expression of fimA, fimD and wza virulence genes showed upregulation, compared to the negative control and downregulated in comparison with the ciprofloxacin treatment. Conclusion: Simultaneous treatment of resistant isolate of K. pneumoniae with f-MWCNTs +antibiotic could improve the effectiveness of antibiotic at lower doses, due to the reduced expression of virulence genes in comparison with antibiotic treatment, besides the increased cell wall permeability to antibiotics.

scholarly journals Prevalence of Virulence Genes and Drug Resistance Profiles of Pseudomonas aeruginosa Isolated From Clinical Specimens

2021 ◽  
Vol 14 (8) ◽  
Author(s):  
Seyed Ali Bazghandi ◽  
Mohsen Arzanlou ◽  
Hadi Peeridogaheh ◽  
Hamid Vaez ◽  
Amirhossein Sahebkar ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Drug Resistance ◽  
Antibiotic Resistance ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Clinical Specimens ◽  
Resistance Rates

Background: Drug resistance and virulence genes are two key factors for the colonization of Pseudomonas aeruginosa in settings with high antibiotic pressure, such as hospitals, and the development of hospital-acquired infections. Objectives: The objective of this study was to investigate the prevalence of drug resistance and virulence gene profiles in clinical isolates of P. aeruginosa in Ardabil, Iran. Methods: A total of 84 P. aeruginosa isolates were collected from clinical specimens of Ardabil hospitals and confirmed using laboratory standard tests. The disk diffusion method was used for antibiotic susceptibility testing and polymerase chain reaction (PCR) for the identification of P. aeruginosa virulence genes. Results: The highest and the lowest antibiotic resistance rates of P. aeruginosa strains were against ticarcillin-clavulanate (94%) and doripenem (33.3%), respectively. In addition, the frequency of multidrug-resistant (MDR) P. aeruginosa was 55.9%. The prevalence of virulence factor genes was as follows: algD 84.5%, lasB 86.9%, plcH 86.9%, plcN 86.9%, exoU 56%, exoS 51.2%, toxA 81%, nan1 13.1%, and pilB 33.3%. A significant association was observed between resistance to some antibiotics and the prevalence of virulence genes in P. aeruginosa. Conclusions: Our results revealed a high prevalence of antibiotic resistance, especially MDR, and virulence-associated genes in clinical isolates of P. aeruginosa in Ardabil hospitals. Owing to the low resistance rates against doripenem, gentamicin, and tobramycin, these antibiotics are recommended for the treatment of infections caused by highly resistant and virulent P. aeruginosa strains.

scholarly journals Molecular characterisation of antimicrobial resistance and virulence genes in Escherichia coli strains isolated from diarrhoeic and healthy rabbits in Tunisia

2020 ◽  
Vol 28 (2) ◽  
pp. 81
Author(s):  
Raouia Ben Rhouma ◽  
Ahlem Jouini ◽  
Amira Klibi ◽  
Safa Hamrouni ◽  
Aziza Boubaker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Antibiotic Resistance Genes ◽  
Virulence Gene ◽  
Diffusion Method ◽  
Class 1 Integron ◽  
E Coli ◽  
Class 1

The purpose of this study was to identify <em>Escherichia coli</em> isolates in diarrhoeic and healthy rabbits in Tunisia and characterise their virulence and antibiotic resistance genes. In the 2014-2015 period, 60 faecal samples from diarrhoeic and healthy rabbits were collected from different breeding farms in Tunisia. Susceptibility to 14 antimicrobial agents was tested by disc diffusion method and the mechanisms of gene resistance were evaluated using polymerase chain reaction and sequencing methods. Forty <em>E. coli</em> isolates were recovered in selective media. High frequency of resistance to tetracycline (95%) was detected, followed by different levels of resistance to sulphonamide (72.5%), streptomycin (62.5%), trimethoprim-sulfamethoxazole (60%), nalidixic acid (32.5%), ampicillin (37.5%) and ticarcillin (35%). <em>E. coli</em> strains were susceptible to cefotaxime, ceftazidime and imipenem. Different variants of bla<sub>TEM</sub>, <em>tet</em>, <em>sul</em> genes were detected in most of the strains resistant to ampicillin, tetracycline and sulphonamide, respectively. The presence of class 1 integron was studied in 29 sulphonamide-resistant <em>E. coli</em> strains from which 15 harboured class 1 integron with four different arrangements of gene cassettes, <em>dfrA17</em>+<em>aadA5</em> (n=9), <em>dfrA1</em> + <em>aadA1</em> (n=4), <em>dfrA12</em> + <em>addA2</em> (n=1), <em>dfrA12</em>+<em>orf</em>+<em>addA2</em> (n=1). The <em>qnrB</em> gene was detected in six strains out of 13 quinolone-resistant <em>E. coli</em> strains. Seventeen <em>E. coli</em> isolates from diarrhoeic rabbits harboured the enteropathogenic eae genes associated with different virulence genes tested (<em>fimA</em>, <em>cnf1</em>, <em>aer</em>), and affiliated to B2 (n=8) and D (n=9) phylogroups. Isolated <em>E. coli</em> strains from healthy rabbit were harbouring <em>fim A</em> and/or <em>cnf1</em> genes and affiliated to A and B1 phylogroups. This study showed that <em>E. coli</em> strains from the intestinal tract of rabbits are resistant to the widely prescribed antibiotics in medicine. Therefore, they constitute a reservoir of antimicrobial-resistant genes, which may play a significant role in the spread of antimicrobial resistance. In addition, the eae virulence gene seemed to be implicated in diarrhoea in breeder rabbits in Tunisia.

scholarly journals Distribution of Virulence Genes Among Methicillin-resistant Staphylococcus Aureus of Clinical and Environmental Origin

2020 ◽  
Author(s):  
Deepshikha Bhowmik ◽  
Shiela Chetri ◽  
Bhaskar Jyoti Das ◽  
Debadatta Dhar Chanda ◽  
Amitabha Bhattacharjee
Keyword(s):  
Staphylococcus Aureus ◽  
Multidrug Resistance ◽  
Virulence Genes ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Virulence Gene ◽  
Type I ◽  
Type Ii ◽  
Methicillin Resistant ◽  
Type Iv ◽  
Type V

Abstract Objective: This study was designed to discover the dissemination of virulence genes in Methicillin-resistant Staphylococcus aureus from clinical and environmental settings. Results: The virulence gene such as sea (n=54), seb (n=21), eta (n=27), etb (n=2), cna (n=24), ica (n=2) and tst (n=30) was revealed from this study. Different SCCmec types such as type I, type II, type III, type IV, type V, type VI, type VII, type VIII and type XII were detected among sixty three MRSA isolates where SCCmec type II having ST1551 and type V with ST2416 were found to be associated with multidrug resistance and were highly prevalent in the study area.

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