Stn Gene Research Articles

Prevalence of Multidrug-Resistant Salmonella enterica Serovars in Buffalo Meat in Egypt.

The current study aimed to investigate the presence of Salmonella spp. prevalence in buffalo meat in Egypt, along with studying the antimicrobial susceptibility of the recovered isolates. Salmonella spp. was detected in 25% of tested buffalo meat. A total of 53 (100%) isolates were genetically verified by PCR as Salmonella, based on the detection of the invA gene. The stn and hilA genes were detected in 71.7% (38/53), and 83.0% (44/53) of the recovered isolates, respectively. Salmonella Enteritidis (11/53; 20.7%) was the most commonly isolated serovar, followed by S. Typhimurium (9/53; 17%), S. Montevideo (6/53; 11.3%), meanwhile, S. Chester, S. Derby, S. Papuana, and S. Saintpaul were the least commonly identified serovars (a single strain for each; 1.9%). Among the 16 antimicrobials tested, amikacin, imipenem, gentamicin, cefotaxime, meropenem, ciprofloxacin, and enrofloxacin were the most effective drugs, with bacterial susceptibility percentages of 98.1%, 94.3%, 92.5%, 86.8%, 83.0%, 73.6%, and 69.8%, respectively. Meanwhile, the least effective ones were erythromycin, streptomycin, clindamycin, cefepime, and nalidixic acid, with bacterial resistance percentages of 100%, 98.1%, 88.7%, 77.4%, and 66%, respectively. Interestingly, the high contamination level of Egyptian buffalo meat with multidrug-resistant Salmonella (79.2%; 42/53) can constitute a problem for public health. Therefore, programs to control Salmonella contamination are needed in Egypt.

Highly Efficient DNA Reporter for CRISPR/Cas12a-Based Specific and Sensitive Biosensor.

In addition to cis-cleavage activity that recognizes and cleaves nucleic acid sequences, a trans-cleavage activity that indiscriminately and non-specifically cleaves single-stranded DNA or RNA has been discovered in some Cas proteins, including Cas12a and Cas13a. Various detection methods using this activity have been widely reported. Herein, we describe a new highly efficient DNA reporter (5′-TTATT-CCCCC-3′; TTATT-5C) that outperformed the existing AT-rich DNA reporter (5′-TTATT-3′) used in most Cas12a-based target nucleic detection assays. By systematically investigating the effect of DNA reporter length and sequence on the trans-cleavage activity of Cas12a, we achieved up to a 100-fold increase in fluorescence signal intensity derived from the trans-cleavage activity of Cas12a compared to that achieved using the existing AT-rich DNA reporter. The new DNA reporter was also applied, along with the existing AT-rich DNA reporter, for the detection of the Salmonella enterotoxin (stn) gene. Importantly, both detection speed and limit were significantly enhanced with the new DNA reporter. In addition, polymerase chain reaction (PCR) was adopted to the CRISR/Cas-Based system of the new DNA reporter, thereby confirming its practical applicability. The high-efficiency DNA reporter described herein can pave the way for further improving the trans-cleavage activity of other Cas proteins, as well as the sensitivity of CRISPR/Cas-Based systems. Supplementary InformationThe online version contains supplementary material available at 10.1007/s13206-022-00081-0.

Salmonella serovars in sheep and goats and their probable zoonotic potential to humans in Suez Canal Area, Egypt

BackgroundSalmonella is one of the most common and economically important zoonotic pathogens. This study aimed to determine the occurrence of Salmonella serovars in sheep and goats and their probable zoonotic risk to humans in Suez Canal area in Egypt. A total of 320 fecal samples from sheep (n = 120), goats (n = 100), and humans (n = 100) were collected and examined for the presence of Salmonella based on cultural and biochemical characteristics, and serological analysis. Moreover, the virulence of the identified Salmonella isolates was assessed by molecular screening for invA, stn, spvC, and sopB virulence genes using PCR.ResultsOverall, the occurrence of Salmonella in sheep feces (23.3%) was higher than that in goat feces (7%) and human stool (13%) in the study area. The identified isolates belonged to 12 serotypes; ten, five, and eight from sheep, goats, and humans, respectively. The most frequently identified serotypes were S. Typhimurium from sheep feces, and S. Enteritidis from both goat feces and human stool, with four serotypes; S. Typhimurium, S. Enteritidis, S. Dublin and S. Saintpaul, were mutually shared between all of them. Demographic data revealed that diarrheic sheep (85.7%) and goats (25%) had a higher risk for Salmonella fecal carriage than non-diarrheic ones (19.5% and 6.25%, respectively). The prevalence of Salmonella infection in humans in contact with sheep and goats (28%) was significantly higher than its prevalence in people having a history of contact with animals other than sheep and goats (10%) and those having no history of animal contact (7.3%) (χ2 = 6.728, P ˂ 0.05). The stn, spvC, and sopB genes were detected in 98.1% of the isolates, with a significant, very strong positive correlation for their mutual presence (P < 0.05). Approximately 40.7% of isolates that carried the invA gene had a non-significant, very weak positive correlation with other virulence genes. The most common genotypic virulence profile for all isolates was stn, spvC, and sopB; however, invA, stn, spvC, and sopB was the frequent virulotype for S. Typhimurium, S. Tsevie, S. Apeyeme, and S. Infantis.ConclusionsThe present study highlights the role of apparently healthy and diarrheic sheep and goats as reservoirs and sources of human infection with virulent Salmonella serovars in the Suez Canal area.

Direct detection of iro B, stn and hil A virulence genes in Salmonella enterica serovar typhimurium from non-ripened cheese

BackgroundMicroorganisms' survival is based on the importance of growth factors found in the microbial environment, as well as their overwhelming appetite for survival which is controlled by their genetic material. This study was designed to investigate the virulence patterns of Salmonella enterica serovar typhimurium associated with soft cheese. Two hundred and sixty (260) soft cheese samples were collected from vendors at Akure, Ikare and Owo in Ondo State, Nigeria. Molecular characterization of six (6) Salmonella enterica isolates for the possession of iro B, stn, hil A and spv C gene were revealed through multiplex polymerase chain reaction (PCR) analysis with DNA extraction, polymerase chain reaction (PCR) amplification, sequencing and genome blasting, respectively.ResultsFour (4) possess only iro B; two (2) possess only stn gene; and another three (3) possess hil A gene as none of the isolates possess spv C gene. This study revealed antibiotic-resistant Salmonella enterica serovar typhimurium is present in locally made soft cheese samples. It also revealed that virulence genes comprising hil A, stn and iro B as well as plasmids-mediating antibiotic resistance are present in S. enterica serovar typhimurium found in locally produced cheese.ConclusionsThe presence of molecularly elucidated virulence genes comprising Iro B, Stn and Hil A makes the soft cheese potentially viable for pathogenicity. This study recommends food-borne salmonellosis should be constantly monitored with appropriate cleaning of preparatory paraphernalia in cheese production. Constant sensitization of nomads to improve their awareness on milk-borne zoonosis and its associated risk factors is needed.

Prevalence of Shiga toxin-producing Escherichia coli and Salmonellae and some associated hematologic and biochemical profile alterations in lambs.

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.

Anti-Biofilms’ Activity of Garlic and Thyme Essential Oils against Salmonella typhimurium

Biofilm control by essential oil (EO) application has recently increased to preclude biofilm production on foods and environmental surfaces. In this work, the anti-biofilm effects of garlic and thyme essential oils using the minimum inhibitory concentration (MIC) method against Salmonella typhimurium recovered from different abattoir samples were investigated along with the virulence genes (InvA, SdiA and Stn genes), and the antimicrobial susceptibility profile of S. typhimurium as well. The obtained results revealed that S. typhimurium contaminated abattoir samples to varying degrees. The InvA gene was investigated in all isolates, whereas the SdiA and Stn genes were observed in four and three isolates, respectively. Utilizing the disc diffusion method, S. typhimurium isolates demonstrated substantial resistance to most of the examined antibiotics with a high multiple antibiotic resistance index. S. typhimurium isolates demonstrated biofilm formation abilities to various degrees at varied temperatures levels (4 °C and 37 °C). In conclusion, the obtained samples from the research area are regarded as a potential S. typhimurium contamination source. Furthermore, garlic essential oil (GEO) has more potential to inhibit S. typhimurium biofilm at different sub-minimum inhibitory concentrations as compared to thyme essential oil (TEO). Therefore, these EOs are considered as potential natural antibacterial options that could be applied in food industry.

Loop-mediated isothermal amplification-based nucleic acid lateral flow assay for the specific and multiplex detection of genetic markers

In this study, a loop-mediated isothermal amplification-based nucleic acid lateral flow assay (LAMP-NALFA) system was developed for the specific and multiplex detection of genetic markers at a low cost. In principle, the LAMP reaction was optimized to generate a single-stranded sequence in the LAMP product, which was designed to serve as a barcode sequence and to specifically bind to the DNA capture on a NALFA strip. As a target genetic marker, the Salmonella enterotoxin (stn) gene was chosen and determined down to 9 aM (∼5.44 copies/μL). Importantly, the proposed system clearly discriminated the specific target amplification products from non-specific amplification products resulting from primers or non-target nucleic acids, proving the high selectivity of the LAMP-NALFA system. Furthermore, the practical applicability of the system was demonstrated by detecting Salmonella bacteria in Luria-Bertani medium, drinking water, and eggshells, with a limit of detection of 1.6 CFU. Finally, two different bacteria (Salmonella and Staphylococcus) were simultaneously determined by the multiplex LAMP-NALFA system. It is expected that the LAMP-NALFA system could be used in a point-of-care setting for the detection of bacteria or viruses, consequently improving both individual and public health.

Molecular Epidemiology of Salmonella enterica in Poultry in South Africa Using the Farm-to-Fork Approach.

The presence of the zoonotic pathogen Salmonella in the food supply chain poses a serious public health threat. This study describes the prevalence, susceptibility profiles, virulence patterns, and clonality of Salmonella from a poultry flock monitored over six weeks, using the farm-to-fork approach. Salmonella was isolated using selective media and confirmed to the genus and species level by real-time polymerase chain reaction (RT-PCR) of the invA and iroB genes, respectively. Antimicrobial susceptibility profiles were determined using Vitek-2 and the Kirby–Bauer disk diffusion method against a panel of 21 antibiotics recommended by the World Health Organisation Advisory Group on Integrated Surveillance of Antimicrobial Resistance (WHO-AGISAR). Selected virulence genes were identified by conventional PCR, and clonality was determined using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). Salmonella was present in 32.1% of the samples: on the farm (30.9%), at the abattoir (0.6%), and during house decontamination (0.6%). A total of 210 isolates contained the invA and iroB genes. Litter, faeces, and carcass rinsate isolates were classified as resistant to cefuroxime (45.2%), cefoxitin (1.9%), chloramphenicol (1.9%), nitrofurantoin (0.4%), pefloxacin (11.4%), and azithromycin (11%). Multidrug resistance (MDR) was observed among 3.8% of the isolates. All wastewater and 72.4% of carcass rinsate isolates were fully susceptible. All isolates harboured the misL, orfL, pipD, stn, spiC, hilA, and sopB virulence genes, while pefA, spvA, spvB, and spvC were absent. In addition, fliC was only present among the wastewater isolates. Various ERIC-PCR patterns were observed throughout the continuum with different subtypes, indicating the unrelated spread of Salmonella. This study concluded that poultry and the poultry environment serve as reservoirs for resistant and pathogenic Salmonella. However, there was no evidence of transmission along the farm-to-fork continuum.

Characterization of virulence factors of Salmonella isolated from human stools and street food in urban areas of Burkina Faso

BackgroundThis study was undertaken to identify and functionally characterize virulence genes from Salmonella isolates in street food and stool cultures. From February 2017 to May 2018, clinical and food Salmonella strains were isolated in three regions in Burkina Faso. Salmonella was serotyped according to the White-Kauffmann-Le Minor method, and polymerase chain reaction (PCR) was used to detec invA, spvR, spvC, fimA and stn virulence genes commonly associated with salmonellosis in Sub-Saharan Africa.ResultsA total of 106 Salmonella isolates (77 human stools; 14 sandwiches) was analyzed using a serological identification with an O-group test reagent. The presence of Salmonella was confirmed in 86% (91/106) of the samples were reactive (OMA-positive/OMB-positive). Salmonella serogroup O:4,5 was the most common serogroup detected (40%; 36/91). Salmonella Enteritidis and Typhimurium represented 5.5% (5/91) and 3.3% (3/91), respectively and were identified only from clinical isolates. Furthermore, 14 serotypes of Salmonella (12/91 human strains and 2/15 sandwich strains) were evocative of Kentucky/Bargny serotype. For the genetic profile, 66% (70/106) of the Salmonella had invA and stn genes; 77.4% (82/106) had the fimA gene. The spvR gene was found in 36.8% (39/106) of the isolates while 48.1% (51/106) had the spvC gene. Among the identified Salmonella Enteritidis and Salmonella Typhimurium isolated from stools, the virulence genes detected were invA (3/5) versus (2/3), fimA (4/5) versus (3/3), stn (3/5) versus (2/3), spvR (4/5) versus (2/3) and spvC (3/5) versus (2/3), respectively.ConclusionThis study reports the prevalence of Salmonella serotypes and virulence genes in clinical isolates and in street foods. It shows that food could be a significant source of Salmonella transmission to humans. Our results could help decision-making by the Burkina Faso health authority in the fight against street food-related diseases, in particular by training restaurateurs in food hygiene.

Implication of bats in the transmission of zoonotic strains of Salmonella in Benin

Bats play a very important role in the transmission of zoonosis, including Salmonella. Salmonella are responsible for salmonellosis, which is a major public health concern. They are the cause of many hospitalizations and deaths worldwide. The objective of this study was to contribute to the im-provement of the control of zoonotic strains of Salmonella in Benin. To do so, a collection of 400 bats was made and after slaughter and dissection, bacteriological analyses were made on the gut to isolate and identify the different strains of Salmonella carried by these bats. The resistance profile and the presence of specific virulence gene such invA, spvR, spvC and stn were studied. The strain Salmonella Typhimurium ATCC 14028 was used as a positive control. Of the 400 bats slaughtered, 14 isolate of Salmonella spp were identified by API gallery. Therefore, the prevalence of Salmonella strains in bats was 3.5%. Salmonella spp strains isolated showed total re-sistance to amoxicillin, clavulanic acid and also to first and second genera-tions of cephalosporins. The stn and invA genes have been found in the DNA of all strains of Salmonella isolated. The consumption of bats being a com-mon practice in Benin, the risk of virulent Salmonella strains transmission must be taken very seriously and people must be sensitized to this in order to slow down the risk of infection.

Sequencing and phylogenetic analysis of the stn gene of Salmonella species isolated from different environmental sources at Lake Qarun protectorate: The role of migratory birds and public health importance.

Background and Aim:Salmonella causes most foodborne bacterial illnesses worldwide. It is found in various hosts, including pets, farm animals, and wild animals, as well as the environment. This study aimed to examine the epidemiological relationship between Salmonella isolates from aquatic environments and those from other avian hosts.Materials and Methods:The study examined 12 water samples, 210 aquatic animals, and 45 migratory aquatic bird samples collected from the protected area of Lake Qarun in El-Fayoum Governorate, Egypt, during migration seasons from different waterfowl migration areas (from October 2018 to January 2019). In addition, 45 fecal samples from domestic chickens were collected from the same geographic location from poultry farms. Bacteriological examination and polymerase chain reaction assay of two virulence genes (i.e., invA and stn) were performed to isolate and identify Salmonella.Results:Salmonella was isolated from 58.3% (7/12) of Lake Qarun water samples, 13.3% (6/45) of migratory waterfowl, 6.6% of (3/45) of chickens (Gallus gallus domesticus), and 4.3% (3/70) of fish and pooled brine shrimp. In migratory aquatic bird species that were sampled, Salmonella were isolated from 23.1% (3/13) of Eurasian coot (Fulica atra), 12.5%, (1/8) of green-winged teal (Anas cardolinesis), 10% (2/20) of northern shoveler (Spatula clypeata), and 0% (0/4) of mallard duck (Anas platyrhynchos). In 35 Tilapia, Salmonella was isolated by (8.6%) 5.7% of external surfaces, 2.85% from the intestine, and 0% from the muscle. No Salmonella was isolated from the 175 brine shrimp samples. Phylogenetic analysis using the stn genes of Salmonella isolated from the aquatic environment, migratory aquatic birds, and chicken showed a strong association between these isolates. In addition, a higher nucleotide identity percentage was observed between the sequences recovered from migratory aquatic birds and Lake Qarun water samples.Conclusion:Salmonella distribution was confirmed through migratory aquatic birds, based on our phylogeny tree analysis, Salmonella considered a likely carrier of zoonotic bacterial pathogens. Furthermore, the close relationship between chicken and fish sequences highlights the scenarios of using chicken manure in fish farms and its public health implications. The presence of Salmonella in different environmental sources spotlights the urgent need to control and break down its epidemiological cycle.

Antimicrobial Resistance, Virulence Associated Genes and Biofilm Formation of Salmonella Species Isolated from Different Sources

Infections with Salmonella species are among the major foodborne outbreaks of concern globally. This study aimed to characterize virulence determinants, antibiotic susceptibilities and biofilm formation ability of 29 Salmonella spp. isolated from chicken and human sources in Egypt. Molecular identification of virulence-associated genes revealed the detection of avrA gene in 100% of the examined isolates. The sopB, stn, hilA and bcfC genes were identified in 91.3% of the isolates, while, 86.2% and 31.03% harbored mgtC gene and spvC genes, respectively. The pefA and fimH genes were only identified in three isolates (10.3%). Fifteen antimicrobials were chosen to assess the susceptibility of the isolates to these drugs. The majority (31.03%) was resistant to 10 antibiotics; meanwhile, 89.6% were resistant to at least 5 antimicrobials. Out of 29 Salmonella isolates, 89.76%, 82.8% and 37.9% were biofilm producers at 35°C, 25°C, and 4°C, respectively. Significant correlation was observed between different Salmonella serotypes and their ability to produce biofilms. In conclusion, frequent monitoring of virulence determinants, antibiotic susceptibility and biofilm characteristics of Salmonella spp. is essential to improve food safety.

Critical occurrence of verotoxgenic E.coli and non-typhoidal salmonella in some heat treated dairy products.

Pathogenic strains of E.coli and Salmonella are common causes of foodborne illness and have been frequently isolated from inadequately heat-treated milk products in Mansoura city. The current study was performed to explore the prevalence of E.coli and Salmonella spp. in heattreated milk products intended for consumption in Mansoura university hospitals and hostels, as well as, to investigate their serotypes and virulence potential. Seventyfive samples of heat-treated milk products (Soft cheese, yoghurt, and processed cheese, 25 of each) were randomly gathered and directed to further investigation using conventional and molecular microbiology. Result revealed that 3(12%) of soft cheese samples harbored E.coli O146:H21, O26:H11 and O128:H2 serotypes and 2(8%) of yoghurt samples were contaminated with O128:H2 and O121:H7 serotypes while 3(12%) of processed cheese samples were positive for non-typhoidal Salmonella (NTS) serovars (Salmonella Typhimurium, Salmonella Infantis and Salmonella Essen). Virulence gene profiling reported that all E.coli isolates harbored eaeA gene and only E.coli O26:H11 and O121:H7 encoded stx2 (verotoxin) gene. Further, all Salmonella isolates harbored invA and stn genes, while only Salmonella Typhimurium and Salmonella Infantis encoded spvC gene. This study confirmed the existence of highly pathogenic verotoxogenic E.coli (VTEC) and NTS in investigated milk products which could be hazardous for public health and resident in Mansoura hospitals and hostels. Hence, the implementation of good hygienic practices together with hazard analysis, and risk-based preventive control measures are rigorously required in the process of HACCP plan to eliminate the risk of contamination that may occur during the manufacturing process.

The emergence of extended-spectrum β-lactamase (ESBL)-producing Salmonella London isolates from human patients, retail meats and chickens in southern China and the evaluation of the potential risk factors of Salmonella London

Salmonella is a major foodborne pathogen that causes a broad range of infection in humans and animals. This research was undertaken to investigate the antimicrobial resistance, virulence genes and genotyping of the extended-spectrum β-lactamase (ESBL)-producing Salmonella London (S. London) isolates originating from human patients, retail meats and chickens in southern China. The high antimicrobial resistance rates to trimethoprim/sulfamethoxazole (100%), methoxypyrimidine (100%), sulfaisoxazole (100%), ampicillin (73.68%) and amoxicillin (63.16%) were observed among a total of 19 S. London isolates, and the particular concern is that all isolates exhibited multidrug resistance (MDR). The ESBL-positive phenotype, which is resistant to antibiotics such as ampicillin, ceftazidime and cefotaxime, was observed in the isolates (15/19). These strains harbor the emerging ESBL-coding genes blaSHV, blaTEM-1, blaCTX-M and blaOXA, and co-harbor the virulence genes stn, invA, sseL and virK. In addition, the predominant genotypic virulence profile was characterized by the presence of stn, fimA, virK, invA, sseL, mgtC, siiE and sopB genes in the strains. The profiles of enterobacterial repetitive intergenic consensus (ERIC)-PCR revealed that S. London isolates with genetic diversity were widely disseminated. This study highlights the potential threat to public health posed by the foodborne transmission of the multidrug-resistant S. London isolates from diverse sources.

Detection of aerobic bacterial pathogens associated with early embryonic death in pregnant New Zealand female Rabbits in Egypt.

Background and Aim:Rabbits are a highly sensitive species and susceptible to various bacterial pathogens that may be causative agents for early embryonic death. This study aimed to explore the administration of different bacterial agents in does suffering from early embryonic death. Furthermore, identification of genes associated with virulence was performed to identify the phenotypic and genotypic antimicrobial resistance patterns that may increase the virulence of pathogens and lead to early embryonic death.Materials and Methods:We isolated and identified bacterial agents in 106 samples from live and dead female rabbits that had undergone early embryonic death, including liver and intestine tissue, aborted fetuses, discharges, and vaginal swabs. Conventional polymerase chain reaction (PCR) was conducted to confirm the identity of the isolated bacterial strains and their virulence. Moreover, antibiotic resistance was studied phenotypically and genotypically.Results:We isolated Escherichia coli, Salmonella, Staphylococcus aureus, Pasteurella multocida, and Listeria monocytogenes. PCR confirmed typical identification except in P. multocida, which was confirmed as Gallibacterium spp. in some cases. The final percentage of detection was 34%, 30.2%, 16.9%, 13.2%, and 11.3%, respectively. Virulence properties were investigated using different designated genes. All Salmonella strains harbored invA, stn, avrA, and ompf genes, while the sopE gene was identified in 31.25%. E. coli strains harboring the iss gene lacked the shiga toxin (stx1) gene. L. monocytogenes and S. aureus strains harbored the hemolysin gene (66.7% and 33.4%, respectively). Multidrug resistance was detected phenotypically and genotypically in most strains. Each bacterial pathogen had a different antibiotic resistance profile.Conclusion:Multiple bacterial species may contribute to early embryonic death in does. Furthermore, the combined infection could be the main cause of early embryonic death. Thus, monitoring programs should bear this in mind and focus on the early detection of these bacterial agents in female rabbits to avoid embryonic death.

Virulence -Determinants and Antibiotic Resistance Pattern of Salmonella Species Isolates from Fancy Pigeons in Port-Said Governorate, Egypt

This study was carried out to investigate the prevalence of salmonellosis among fancy pigeons in Port- Said Governorate, Egypt. Two hundred (150 pet stores and 50 lofts) samples were collected from pigeons suffered from general signs of illness, joint lesions and diarrhea. Bacteriological and serological analysis revealed 12 (6%) isolate of Salmonella species distributed among eight serotypes, in which S. Virchow was more frequently isolated (25%), followed by S. Typhimurium and S. Paratyphi (16.6% each). Meanwhile, S. Akay, S. Salamae, S. Anderlecht, S. Magherafelt and S. Montevideo were 8.3%, each. All Salmonella isolates showed 100% sensitivity towards norfloxacin followed by ciprofloxacin (83.3%). On the other hand, ten Salmonella serotypes showed high resistance to erythromycin and rifampicin by 91.7 %. However, 42.1% of the recovered isolates exhibited Multi drug resistant (MDR) and 16.6% exhibited Extensive drug resistant (XDR) to different antibiotics. Molecular detection of 5 virulence genes (invA, stn, sop E1, pefAand fimH) among four chosen Salmonella serotypes (S. Paratyphi, S. Typhimurium, S. Virchow, S. Montevideo) using conventional PCR revealed the presence of invA, stn and fimH genes in all examined Salmonella serotypes. Meanwhile, sop E1 and pefA genes were detected only between S. Virchow and S. Typhimurium, respectively.

Outer membrane proteins (OMPs) profiling of a field isolate of Salmonella Typhimurium: Isolation and its characterization

Salmonella Typhimurium is a significant zoonotic pathogen affecting human and animal health. In the present study, a S. Typhimurium isolate, previously isolated from poultry samples was revived and re-confirmed as S. Typhimurium by isolation in Hektoen enteric agar followed by molecular detection. PCR with the stn gene, his J gene and Typh gene primers revealed the specific amplicon of size 617 bp, 496 bp and 402 bp respectively. Antibiotic sensitivity pattern of the isolate was also determined. Isolate was then cultured in LB broth in bulk and outer membrane proteins (OMPs) were isolated by ultracentrifugation. The OMPs were successfully isolated and confirmed by SDS-PAGE analysis. The band pattern revealed nine major bands ranging from 11-90 kDa.

Prevalence of virulent genes in Salmonella isolated from some raw meat products By DR.Mahmoud Ezzat * Helal, I. M. *Hagar G. Elbakry ** mezzat05@yahoo.com ihabhelal@yahoo.com bakry_hagar@yahoo.com *Bacteriology department, Faculty of Vet. Med., Suez Canal University and **Food Hygiene Department (Port-Said branch), Animal Health Research Institute, ARC

Two hundred random samples of raw meat products were collected from different markets in Port- Said city under aseptic condition for isolation and identification of Salmonella spp. The results revealed the isolation of 7 Salmonella isolates with a percentage of 3.5%. The isolates were S. Anatum, S. Enteritidis, S. Hato and S. Lamberhurst with a percentage of 28.6%, 14.3%, 28.6% and 28.6% respectively. The antibiotic resistance of Salmonella isolates was detected for 12 antibacterial agents by disk diffusion method. All the isolates were resistant to Amoxicilline/clavulinic a., Doxicyciline and Erythromycin. One hundred percent of the isolates were sensitive to Ciprofloxacin, Chloramphenicol and Gentamycin. The PCR assays using specific primers for the detection of different virulence genes of Salmonella spp. revealed the presence of invA, csgD, stn, ompA and ompF genes in all 7 Salmonella serovars. The public health hazard of theses isolated strains, as well as recommended measures to improve quality status of processed meet were discussed.Key words: Salmonella spp., processed meat, antibacterial resistance genes, PCR, Public health.

Molecular Analysis of Some Virulence Genes of Salmonellae Isolated from Chicken at Sharkia Governorate

Poultry is one of the most reservoirs of Salmonella that can be transmitted to humans through the food chain causing high risk bacterial food poisoning. In the present study, bacteriological examination of 200 samples from broiler internal organs (liver,2ceci, un absorbed yolk sac) from1 day old chicks suffering from omphalitis and respiratory disorders after hatching, revealed 26 Salmonella isolates 13%. Serotyping of 26 Salmonella isolates by slide agglutination test using specific monovalent and polyvalent O and H Salmonella sera revealed eleven different Salmonella serotypes, with S. Enteritidis as the most prevalent serotype (38.5%) followed by S.Tamale (23.07%). ,S. Typhymurium (19.2%), S. Kentucky (15.4%)and ,S.Heldberg (3.8%).most Salmonella isolates were sensitive to Ciprofloxacin ,sulfa methoxasole – trimethoprime , Chlorumphenicol and gentamycin .while they were resistant to Erythromycin ,Rifamycin , Amoxycillin /clavulinic acid ,colistin sulfate and cefotaxime . PCR detection of 6verulant genes of 5 strains of Salmonella isolates which proved to play an important role in the virulence of Salmonella in chicken. In this study detection of (invA gene, hilA gene, stn gene, spvc gene, fmH gene and pefA gene) is with percentages of (100%, 80%, 100%, 0%, 100% and 40%)respectively. From examined 5MDR Salmonella isolates, Integron class1were detected in all of them (100%) but no strain was found to harbor Integron class2.

Rapid Serotyping of Salmonella Isolates Based on Single Nucleotide Polymorphism-Like Sequence Profiles of a Salmonella-Specific Gene

Although serotyping is the most important method of identification of taxonomy in Salmonella, conventional serotype determination with a complete set of antisera is time consuming and laborious. Recently, rapid serotyping procedures with polymerase chain reaction (PCR) have been developed. In this study, we established a novel PCR-based rapid serotyping method that employs a unique target gene. Alignment study of Salmonella-specific gene (Salmonella enterotoxin [stn]) revealed a correlation between the stn gene sequence and the serotype of the organism. In 750 bp of stn gene, 55 nucleotides indicated single nucleotide polymorphism (SNP)-like polymorphism, and the correlation between the SNP-like polymorphism and the serotype of the organism suggests that SNP-like sequences in stn gene can serve as an index for serotyping. To develop a rapid serotyping method based on the SNP-like polymorphism, we selected serotype-associated 12 SNP-like sites in the stn gene and established a method based on high-resolution melting (HRM) and PCR, which identifies nucleotides at SNP-like sites within 1.5 h. This newly established rapid serotyping procedure (stn-HRM) could identify nine serotypes, including the frequently isolated serovar Enteritidis. These nine serotypes cover 64.3% of cases of Salmonella, as reported by the World Health Organization/Global Foodborne Infection Network (WHO/GFN) Country Databank from 2001 to 2010. In this study, we employed a unique target gene, stn, which is completely independent of the genes that were targeted in previously reported rapid serotyping procedures. Therefore, the results obtained by our newly developed stn-HRM procedure are independent of the results obtained by other procedures. Besides, stn-HRM can ensure accurate identification of the bacterial species as stn is a Salmonella-specific gene. It is expected that the combination of newly constructed stn-HRM and previously reported procedures could further improve the credibility of Salmonella isolate serotyping.