جستجوی مقالات مرتبط با کلیدواژه « Virulence genes » در نشریات گروه « دامپزشکی »

Salmonellosis is increasingly recognized as a worldwide public health concern. Salmonella Infantis can infect both humans and animals, including poultry. It has been one of the most reported isolated serovars from different parts of the world. Although some research has been carried out on the pathogenesis of S. Infantis, little scientific understanding of its pathogenesis is available.

This study aimed to analyze the virulence genes of S. Infantis recovered from different sources of poultry in Iran.

Six virulence genes of 54 S. Infantis strains originated from broiler feces, poultry processing, and broiler carcasses were examined. Gene-specific polymerase chain reactions were designed and employed to detect the presence or absence of 6 important virulence genes (sopB, sopE, sitC, pefA, sipA, and spvC) in 54 S. Infantis isolates.

In this study, sopE, sitC, pefA, sipA, and sopB virulence genes were detected in 51(94.4%), 49(90.7%), 26(48.1%), 15(27.7%), and 5(9.2%) isolates, respectively. The spvC gene was not detected in any of the isolates. 

In the present study, a remarkably identical profile was found on virulence genes’ presence in isolates recovered from broiler feces and poultry processing plant sources, that is a public health concern. However, more S. Infantis isolates from various poultry sources, and human origin should be examined and analyzed. The findings of this survey can help the health researchers better understand the pathogenesis and epidemiology of S. Infantis in Iran.

The increasing importance of antibiotic resistance shows the need for determining indices of the epidemiology of infection.

This study aimed to determine the virulence genes and antibiotic resistance profiles of Staphylococcus aureus isolated from bovine mastitis cases.

A total of 200 cattle were selected based on California Mastitis Test (CMT) results, and the samples were cultured in the laboratory. Grown colonies were examined by conventional phenotypic methods and confirmed using PCR amplification of 16S rRNA gene. The prevalence of the virulence genes was also defined. The results of phenotypic and molecular tests were compared using SPSS software by McNemar test. Then, the confirmed isolates were tested for antibiotic susceptibility using the disc diffusion method.

Of the 200 positive CMT cattle, 24 animals were positive for S. aureus and confirmed using 16S rRNA gene amplification. Statistical analysis showed that the phenotypic and genotypic tests of hemolysin genes were not significantly different (P>0.01). PCR analysis revealed the presence of coa and clfa genes in more than half of the cases. Overall, nine genetic profiles of virulence factors were found among S. aureus isolates. The highest and lowest resistance rates were against penicillin and gentamicin, respectively.

Our findings showed a high rate of antibiotic resistance. So, accurate and fast diagnosis and antimicrobial susceptibility tests should be considered before prescribing the drugs.

Pasteurella multocida exists as a commensal in the upper respiratory tracts of livestock, and poultry, and causes a wide variety of diseases in humans and animals. This study aimed to investigate the incidence of P. multocida by bacteriological and molecular characterization in sheep and goats and screening the existence of capsule-specific genes and their antibiotic resistance pattern. Totally, 1650 nasopharyngeal swabs were collected from apparently healthy sheep and goats and 460 lung tissues were collected from slaughtered animals in Fars province, Iran. All samples were cultured and suspected colonies were examined by biochemical tests, antimicrobial assay and polymerase chain reaction (PCR). Among 165 P. multocida (104 sheep and 61 goats) isolates, the capA, capD, and capB genes were amplified in 98, 48, and 12 isolates, respectively. The occurrence of four virulence-associated genes of P. multocida isolates were determined by PCR. Most isolates harbored the toxA (79.40%) and hgbB genes (70.90%) and 59.40% of isolates had the pfhA gene. Almost half of the isolates (46.10%) contained the tbpA gene. According to the current study, P. multocida capsular type A had the most frequency followed by type D. In addition, the high frequency of tbpA, pfhA, toxA, and hgbB genes revealed that these genes are possibly important in the pathogenesis of P. multocida. Oxytetracycline, enrofloxacin, florfenicol, and tilmicosin were the most effective drugs.

Mastitis is one of the most expensive diseases in the dairy industry. It causes heavy monetary losses by decreasing milk production and treatment cost. Streptococcus agalactiae, the cause of contagious bovine mastitis, possesses various virulence factors that contribute to pathogenicity.

The main aim of the study was to evaluate the distribution of virulence genes of S. agalactiae.

In the current work, 98 Streptococcus species were isolated from 320 milk samples, collected from Veterinary Clinical Complex, Junagadh. Out of the isolates, 42 S. agalactiae isolates were used for virulence genes detection.

All Streptococcus spp. were confirmed at genus level by targeting tuf gene, and S. agalactiae was identified at species level by targeting 16S rRNA gene. For virulence gene detection, scpB, cfb, and cylE genes were targeted. Of 42 S. agalactiae isolates, 15, 16, and 10 isolates possessed scpB, cfb, and cylE genes, respectively.

This study aids us to know virulence characteristics and mechanisms responsible for the development of new strains in mastitis epidemiology in response to prevention and control strategies.

Salmonella species (spp.) are a major source of diarrheal diseases everywhere and one of the most dangerous foodborne bacteria. The present study aimed to detect the occurrence of the most important virulence genes in Salmonella enterica (S. enterica) among bacteria isolated from stool in Baghdad hospitals, Iraq. In total, 50 swab stool samples were collected from patients suffering from food poisoning, attending to different hospitals in Baghdad. The isolates were identified using morphological tests and were confirmed by the Vitek-2 system (BioMe´rieux, France). A genomic DNA kit (Qiagen, Germany) was utilized to extract DNA from the isolates. Molecular detection of five virulence genes, including invA, papC, spvC, stn, and fimH, was performed using Polymerase Chain Reaction (PCR). Out of 50 swab samples, 40% (20 samples) were confirmed as S. enterica. Moreover, the prevalence of virulence genes determined by the PCR demonstrated that all 20 S. enterica isolates carried at least one gene from those associated with biofilm formation. The invA, stn, and fimH were the most predominant genes existing in all 20 S. enterica isolates. The prevalence of papC and spvC virulence genes was 75% (15 out of 20) and 65% (13 out of 20), respectively. The current data support the occurrence of Salmonella spp. exhibiting a broad range of virulence genes in stool samples from patients who had food poisoning, which indeed makes these bacteria a significant threat to public health.

Vibrio species are significant pathogens affecting aquatic species. Around 12 species of Vibrio can cause a gastrointestinal illness (gastroenteritis) in humans resulting from eating contaminated food such as raw or undercooked shellfish. The indiscriminate use of antibiotics accelerates the development of resistance representing a severe challenge for controlling Vibrio outbreaks. In this study, the antibiotic resistance profile and the prevalence of pathogenic Vibrio species of apparently healthy and diseased fishes isolated from different types of fish in Kafr EL-Sheikh Governorate in Egypt during 2018 were determined. Samples obtained from fishes were inoculated onto a Vibrio-selective medium (TCBS) and phenotypically identified using the biochemical characteristics and representative cultures were checked by PCR to confirm the identified isolates. In the present study, V. alginolyticus (16.00%) was the predominant species followed by V. cholerae (7.33%) and V. parahaemolyticus (5.33%). The tested isolates were resistant to ampicillin (80.00%) and sensitive to ciprofloxacin and norfloxacin (100%). A total number of 15 Vibrio isolates (5 Vibrio parahaemolyticus, 5 V. alginolyticus, and 5 V. cholerae) were screened for five housekeeping genes and pathogenic virulence markers by PCR. Results showed that 100% of the V. parahaemolyticus isolates carried the tlh gene and 60.00% carried the tdh gene. In V. alginolyticus, 100% of the isolates carried the collagenase gene 0.00% carry the tdh gene; and 80.00% of V. cholerae isolates carried the ctx gene. The results showed that many isolates in this study had virulence characteristics that might correspond with the potential of infections and diseases.

Campylobacter species are the zoonotic bacteria and the most common cause of foodborne gastroenteritis around the world. The link between human campylobacteriosis and infected poultry consumption has been well established.

In this study, we aimed to isolate Campylobacter spp. from chicken and characterize them with molecular methods.

Totally, 241 chicken caecal mucosal scrapings were collected from five districts of Tamil Nadu. Bacterial isolation was done by plating on blood-free Campylobacter selective medium with supplements. Campylobacter species were identified by multiplex PCR and Campylobacter coli isolates were tested for 11 virulence genes by PCR. C. coli isolates were typed based on seven housekeeping genes multilocus sequence typing (MLST) scheme. The antimicrobial susceptibility was determined by a microdilution resazurin assay.

The prevalence of C. coli and C. jejuni were 14.94% (36/241), and 3.32% (8/241), respectively. The virulence genes flaA, flaB, cadF, cdtA, cdtB, cdtC, ciaB, and ceuE were present in all 36 C. coli isolates, pldA and racR genes were present in 58.33% (21/36), and 16.67% (6/36) of the isolates, respectively, and dnaJ was present in only one isolate. Two novel sequence types (ST-10872, ST-11031) were found in this study. Though different STs were identified, all the STs belonged to the same clonal complex of ST-828. All 14 C. coli isolates showed 100% resistance to nalidixic acid, and higher resistance to tetracycline (92.8%), erythromycin (71.4%), clindamycin (71.4%), and azithromycin (64.2%) was noticed. All C. coli isolates were sensitive to chloramphenicol, and higher sensitivity to ciprofloxacin (78.5%), and gentamicin (71.4%) was observed.

The present study demonstrated that C. coli is more prevalent in broilers than C. jejuni in Tamil Nadu. The presence of C. jejuni and C. coli in chicken caecal samples from the slaughterhouse are indicative of the possibility of public health hazards.

Lamb enteritis constitutes an economic burden on sheep production worldwide. We aimed to estimate the prevalence of Shiga toxin-producing Escherichia coli (STEC) and Salmonellae among diarrheic lambs at Kafrelsheikh Governorate, Egypt and to detect the associated clinical, hematologic, biochemical, and antioxidant parameters. Fifty diarrheic and twenty apparently healthy control lambs were examined clinically, and hematologically. Diarrheic lambs had a significant elevated body temperature, respiratory and pulse rate, most of hemogram para-meters, total proteins and albumin, oxidative stress markers malonaldiahyde and nitric oxide levels, liver enzymes, urea and creatinine than control group. On the other hand, these diarrheic lambs had significant reduction in total leukocyte count and lymphocytes, antioxidant biomarkers super oxide dismutase activities and reduced glutathione than control lambs. E. coli and Salmonella spp. were isolated from 32.00% and 16.00% of diseased lambs, respectively. Serotyping and biochemical tests of examined samples identified 16 E. coli isolates belonged to 10 different serotypes; O6, O8, O26:H11, O75, O84:H21, O103:H2, O114:H4, O121:H7, O128:H2 and O163:H2. All isolates are STEC as they harbor either Shiga-toxin 1 or Shiga-toxin 2 genes or both. One isolate carries intimin gene (eaeA) and classified as EHEC; O26:H11. The obtained nine isolates of Salmonella carry enterotoxin (Stn) genes, eight of them carry hyper-invasive locus (hilA) gene, all isolates belonged to six serotypes; S. Enteritidis, S. Heidelberg, S. Tsevie, S. Typhimurium, S. Essen, and S. Infantis. Lamb diarrhea was prevalent in the studied area and might constitute a veterinary and public health threat. Alteration in hemato-biochemical para-meters and oxidative–anti-oxidant balance could help adopt appropriate treatment regimens.

Aeromonas hydrophila is a bacterium associated with many diseases and disorders such as fin rot, skin ulcers and lethal hemorrhagic septicemia in fish. It bears several virulence factors including type III secretion system (T3SS), aerolysin, cytolytic enterotoxin and enzymes (e.g. hemolysins, lipase) that seem to play an important role in its pathogenesis. Detection of virulence markers by polymerase chain reaction (PCR) is a key procedure in defining the pathogenic ability of pathogenic bacteria and preparing a vaccine for its treatment. In this sense, this study was aimed to determine the frequency of virulence genes in isolates obtained from infected cultured carps in Khuzestan province. Out of 200 moribund carps with septicemic symptoms, 125 isolates were belonged to the motile aeromonads and 59 isolates were identified as A. hydrophila by biochemical methods. Finally, using PCR analysis, 31 isolates were identified as A. hydrophila. Five virulence genes were detected in these isolates including hemolysin, aerolysin, cytolytic enterotoxin and T3SS (aopB and ascV) by specific primers. Results showed that 23 (74.19%), 18 (58.06%), 16 (51.61%), 13 (41.63%) and 10 (32.25%) isolates possessed cytolytic enterotoxin, hemolysin, aerolysin, and T3SS genes, respectively. The results of the present study showed that among 31 isolates, only five isolates had all of dominant virulence genes. Thirteen other isolates had genotypes including hlyA+, aerA+, and act+. The remaining isolates had at least one virulence gene. This study showed that determination of the virulence genes by PCR can be a reliable method to identify a potential pathogenic Aeromonad strain.

Escherichia coli associated infections are major threats in poultry industry owing to severe economic losses each year. This study was conducted to identify E. coli isolates, to evaluate their antibiotic sensitivity and to find out their virulence patterns from infected broilers of Sylhet city in Bangladesh. Using polymerase chain reaction, a total 20 isolates were identified as E. coli from 11 chickens, exhibiting symptoms like colibacillosis and/or diarrhea. All isolates were positive for type-1 fimbrial adhesion (fimH), followed by putative avian hemolysin (hlyF) in 17 isolates; while none of the isolates was amplified with intimin (eaeA). Among 10 tested antibiotics, 100% of the isolates (n = 20) showed resistance to ampicillin, amoxicillin and tetra-cycline; but they were 100% sensitive to gentamicin. Organ specific correlations of antibiotic sensitivity were obtained among the isolates through principal component analysis (PCA) and Agglomerative Hierarchical Clustering (AHC). The 16S rRNA data of two multi-drug resistant isolates revealed closed clustering with clinical E. coli strains which could be indication of their zoonotic potential. In conclusion, the results depict higher prevalence of fimH and hlyF genes and drug resistance patterns of E. coli isolates from broilers in Sylhet city of Bangladesh.

Shiga-toxin-producing Escherichia coli (STEC) is an important food-borne pathogen causing human diseases with severe symptoms. Although the O157 serotype has been mostly isolated from human specimens, the increasing incidence rates of non-O157 serogroups have attracted special attention in recent years. Evaluation of the epidemiology and identification of different characteristics of STEC isolates from raw beef, chicken meat, and vegetable samples in Shiraz, Southwest Iran. Two hundred beef and chicken meat samples from different parts of carcasses and four hundred vegetable samples (carrots, lettuce, cucumber, and leafy greens) were randomly taken; STEC were isolated and confirmed using standard microbiological methods. Antimicrobial susceptibility testing (AST) was performed using the Kirby-Bauer disc diffusion method. Polymerase chain reaction (PCR) was used for the identification of O-serogroups, virulence, and antibiotic resistance genes. 52% of beef, 8% of chicken, and 7.2% of vegetable samples were STEC-positive. Further, the highest frequency of virulence factors belonged to the co-existence of stx1 and stx2. O157 serogroup was only detected in beef (3.8%) and lettuce (16.6%) isolates, while the rates of the non-O157 serogroups were relatively high (up to 44.2%). The highest resistance rate in the STEC isolates of different samples belonged to nalidixic acid (62.5%), tetracycline (55.7%), and ampicillin (48%). Paying more attention to non-O157 serogroups in future studies is recommended due to the relatively high prevalence of theses STEC serogroups in our study. Besides, the high level of resistance to some antibiotics observed in this study needs to be addressed.

Avian pathogenic Escherichia coli (APEC) strains have been associated with various disease conditions in avian species due to virulence attributes associated with the organism.

This study was carried out to determine the in vitro pathogenic characteristics and virulence encoding genes found in E. coli strains associated with colibacillosis in chickens.

Fifty-two stock cultures of E. coli strains isolated from chickens diagnosed of colibacillosis were tested for their ability to produce haemolysis on blood agar and take up Congo red dye. Molecular characterization was carried out by polymerase chain reaction (PCR) amplification of virulence encoding genes associated with APEC.

Eleven (22%) and 41 (71%) were positive for haemolysis on 5% sheep red blood agar and Congo red agar, respectively. Nine virulence-associated genes were detected as follows: FimH (96%), csgA (52%), iss (48%), iut (33%), tsh (21%), cva (15%), kpsII (10%), pap (2%), and felA (2%).

The APEC strains exhibited virulence properties and harbored virulence encoding genes which could be a threat to the poultry population and public health. The putative virulence genes were diverse and different in almost all isolate implying that pathogenesis was multi-factorial and the infection was multi-faceted which could be a source of concern in the detection and control of APEC infections.

Escherichia coli (E.coli) is one of the most common and important causative bacterium of urinary tract infections (UTIs) in both dogs and humans.

This study aimed to identify virulence genes and a phylogenetic group of E. coli isolated from the urine of dogs suffering from UTIs.

E. coli were isolated from urine of dogs suffering from UTIs and tested for the presence of the virulence genes using conventional polymerase chain reaction (PCR) and sequencing method. On day 60 after immunization, half of the fish in each treatment was challenged intraperitoneally and the re- maining half of fish in the oral receiving bacterin groups were challenged by bath method with 1 LD50 and 1 LC50 of a Y. ruckeri local virulent isolate respectively.

Out of a total of 103 samples, 25 were found to be positive for E. coli, of these 20 (80.0%) were identified as aer, 14(56.0%) as pap, 12(48.0%) as sfa, 8(32.0%) as afa, 5(20.0%) as hly and 5(20.0%) as cnf1 genes. None of the isolates carried cnf2 genes.

The study demonstrated a high occurrence of virulence genes. The phylogenetic compar- isons of these gene sequences detected in uropathogenic E. coli isolated from dogs showed high similarity to those present in the urine of humans with urinary tract infection. Phylogenetic comparisons of the virulence genes revealed that hly, sfa , cnf1 and pap matched to group B2, afa to group A and aer to group B2 and D.

Escherichia coli (E.coli) is one of the most common and important causative bacterium of urinary tract infections (UTIs) in both dogs and humans.

This study aimed to identify virulence genes and a phylogenetic group of E. coli isolated from the urine of dogs suffering from UTIs.

E. coli were isolated from urine of dogs suffering from UTIs and tested for the presence of the virulence genes using conventional polymerase chain reaction (PCR) and sequencing method. On day 60 after immunization, half of the fish in each treatment was challenged intraperitoneally and the re- maining half of fish in the oral receiving bacterin groups were challenged by bath method with 1 LD50 and 1 LC50 of a Y. ruckeri local virulent isolate respectively.

Out of a total of 103 samples, 25 were found to be positive for E. coli, of these 20 (80.0%) were identified as aer, 14(56.0%) as pap, 12(48.0%) as sfa, 8(32.0%) as afa, 5(20.0%) as hly and 5(20.0%) as cnf1 genes. None of the isolates carried cnf2 genes.

The study demonstrated a high occurrence of virulence genes. The phylogenetic compar- isons of these gene sequences detected in uropathogenic E. coli isolated from dogs showed high similarity to those present in the urine of humans with urinary tract infection. Phylogenetic comparisons of the virulence genes revealed that hly, sfa , cnf1 and pap matched to group B2, afa to group A and aer to group B2 and D.

Avian pathogenic Escherichia coli (APEC) are responsible for wide ranges of extra-intestinal diseases in poultry including colibacillosis, cellulitis, coligranuloma and yolk sac infection. Numbers of virulence are considered important in the pathogenicity of these diseases. The aims of the present study were phylogenetic typing and virulence genes detection in Escherichia coli isolates from colibacillosis and cellulitis of broiler chickens in poultry slaughterhouses of Shahrbabak region, Kerman, Iran. A total number of eighty three E. coli isolates were taken from broiler chickens with colibacillosis and thirty four isolates were taken from carcasses with cellulitis in the industrial slaughterhouses. Biochemically confirmed E. coli isolates were subjected to polymerase chain reaction assay to determine phylogenetic groups and presence of pap C, sfa/focDE, iucD, afaIB-C, hlyA, fimH and crl virulence genes. Colibacillosis isolates were belonged to A (54.21%), B1 (7.22%), B2 (6.03%) and D (32.53%) phylogroups. Whereas, the isolates from cellulitis cases were belonged to three main phylogroups; A (55.88%), B1 (5.88%) and D (38.24%). Statistical analysis showed a specific association between the presence of crl virulence gene and phylogroups of A and D in colibacillosis isolates. The results showed that the isolates from both diseases in broiler chickens could be assigned to various phylogenetic groups (mainly A(. Also, the virulence genes profile of cellulitis E. coli is completely different from that of colibacillosis in this region.

The current study was aimed to investigate the prevalence of ureC, rsbA, zapA and mrpA virulence genes using polymerase chain reaction (PCR) in Proteus spp. isolated from 5 commercially popular species of pet turtles and comparison of the mrpA gene sequences of Proteus mirabilis isolates with human clinical isolates. A total of 24 isolates in pet turtles were identified, comprised of P. mirabilis (15), Proteus vulgaris (7) and Proteus hauseri (2). The prevalence of ureC, rsbA, zapA and mrpA genes among all identified Proteus spp. isolates were 91.7%, 50%, 45.8% and 45.8%, respectively. The average percentage similarities of mrpA gene sequence of pet turtle P. mirabilis isolates to human urinary and respiratory isolates were 96.35% and 94.85%, respectively. The prevalence of virulence genes and high similarity of mrpA gene sequences between pet turtles and human P. mirabilis isolates revealed that though pet turtles are healthy, these animals may pose a potential risk of urinary and respiratory infections to humans.