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

Background This 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. Results A 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. Conclusion This 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.

Brucella abortus S19 GFP-tagged vaccine allows the serological identification of vaccinated cattle

Bovine brucellosis induces abortion in cows, produces important economic losses, and causes a widely distributed zoonosis. Its eradication was achieved in several countries after sustained vaccination with the live attenuated Brucella abortus S19 vaccine, in combination with the slaughtering of serologically positive animals. S19 induces antibodies against the smooth lipopolysaccharide (S-LPS), making difficult the differentiation of infected from vaccinated bovines. We developed an S19 strain constitutively expressing the green fluorescent protein (S19-GFP) coded in chromosome II. The S19-GFP displays similar biological characteristics and immunogenic and protective efficacies in mice to the parental S19 strain. S19-GFP can be distinguished from S19 and B. abortus field strains by fluorescence and multiplex PCR. Twenty-five heifers were vaccinated withS19-GFP (5×109 CFU) by the subcutaneous or conjunctival routes and some boosted with GFP seven weeks thereafter. Immunized animals were followed up for over three years and tested for anti-S-LPS antibodies by both the Rose Bengal test and a competitive ELISA. Anti-GFP antibodies were detected by an indirect ELISA and Western blotting. In most cases, anti-S-LPS antibodies preceded for several weeks those against GFP. The anti-GFP antibody response was higher in the GFP boosted than in the non-boosted animals. In all cases, the anti-GFP antibodies persisted longer, or at least as long, as those against S-LPS. The drawbacks and potential advantages of using the S19-GFP vaccine for identifying vaccinated animals in infected environments are discussed.

Serological and Hematological Study of Toxoplasmosis in Blood of Newly Born Babies

Serological identification and blood pictures were done for specific IgM and IgG.10% of cases were positive IgM of Toxoplasmosis because have 10 IU/ml (mean) in comparison with control group were 0.11 IU/ml (mean). On other hand 20% of diagnosed cases were positive IgG of Toxoplasmosis because have 11 IU/ml .Two cases were followed for their history one from group IgM and other IgG , first one suffered from three abortion and now have five child three of them healthy while two have congenital defects. Second case (IgG positive ) have four abortion and now have three child , two healthy and one have congenital defect. Blood picture reveal 40% suffered from Normocytic anemia , these cases classified to three groups , first Toxoplasma group 30% (positive in ELISA test). Second group (Unknown causes), these cases not only normocytic anemia also have high total leukocytes 17 x10 (mean) and high MCV (103 ft). Third group have low MCV 78ft.

MICROSCOPIC OBSERVATION OF VARIOUS ORGANS OF PIGEONS WITH SYMPTOMP OF TORTICOLLIS AND IDENTIFICATION OF NEWCASTLE DISEASE VIRUS BASED ON AGAR GEL PRECIPITATION TEST

This study aimed to determine the microscopic conditions of organs of pigeons that suffered from torticollis and identify the cause of disease in torticollis pigeons. Three pigeons showed torticollis symptoms were obtained as sample and marked as pigeon A, B and C, respectively. Isolation of pathogen with inoculation into embryonated pigeon eggs obtained from parents with no history of vaccination and not indicated ND. Identification of ND with agar gel precipitation (AGP) test. Observation of microscopical changes with histopathologic preparation using hematoxylin and eosin staining. Histopathological examination showed that pigeons was done severe neuritis vagus, trakheitis, pneumonia, air sacculitis, hepatitis, pankreatitis, nefritis, jejunoileitis, ileocolitis and orchitis. Perivascular cuffing found in brain. Degenerative changes found in the hepar and ren. Cardiac severe necrotic lesion, and depletion in white pulp area of spleen. Proventricular tissue showed flattening of mucosal epithelium, congestion lesions found in pulmonary tissue. The results of slow hemagglutination test of pigeon egg allantoic fluid, which tested for hemagglutination (HA) showed positive HA result with titers varying between 2, 32, and 64. Serological identification carried out with the AGP test on all culture samples against ND antiserum showing positive results of ND virus. Based on these dara, it can be concluded that the pigeons with symptoms of torticollis is caused by ND virus.

Isolation of enterotoxigenic Staphylococcus aureus harboring seb gene and enteropathogenic Escherichia coli (serogroups O18, O114, and O125) from soft and hard artisanal cheeses in Egypt

Background: Soft and hard artisanal cheeses are regularly consumed in Egypt. These products are usually processed from raw milk which may harbor many pathogenic and spoilage microorganisms.Aim: To evaluate the safety of some artisanal cheeses in Egypt, such as Ras, Domiati, and Mish, through chemical and microbiological examination.Methods: One hundred and fifty random samples of traditional Ras, Domiati, and Mish cheeses (50 each) were microbiologically and chemically analyzed. Counts of total bacteria, presumptive coliform, staphylococci, yeast, and mold were estimated. Furthermore, isolation of Escherichia coli and Staphylococcus aureus was performed, followed by PCR confirmation; isolates of E. coli were examined for the presence of virulence genes; on the other hand, the detection of the five classical enterotoxin genes of S. aureus was performed using multiplex PCR. Regarding chemical analysis, moisture, salt, and acidity content were measured. Correlations between chemical and microbial findings were investigated.Results: Mean counts of total bacteria, presumptive coliform, staphylococci, yeast, and mold were (2 × 108, 3 × 106 and 1 × 107 ), (3 × 105, 5 × 10 and 5 × 102), (1 × 106, 4 × 105 and 1 × 105), (3 × 105, 1 × 105 and 5 × 105), and (7 × 103, 4 × 103 and 3 × 104) for Ras, Domiati and Mish cheeses, respectively. Serological identification of suspected E. coli revealed that E. coli O125 was isolated from Ras and Domiati samples, E. coli O18 was recovered from Ras samples, while E. coli O114 was isolated from Mish samples. PCR results revealed that all detected isolates of E. coli were positive for both iss (increased serum survival) and fimH (type 1 fimbriae) genes. Concerning isolated S. aureus, all examined products were harboring S. aureus enterotoxigenic strains, with seb and sed genes being the most common. The mean values of moisture, salt, and acidity were (30.03, 56.44, and 58.70), (3.30, 6.63, and 7.56) and (0.65, 0.68, and 0.50) for Ras, Domiati, and Mish cheeses, respectively.Conclusion: Enterotoxigenic S. aureus harboring seb gene and enteropathogenic E. coli (serogroups O18, O114, and O125) were frequently isolated from soft and hard artisanal cheeses in Egypt. Therefore, strict hygienic measures should be applied during their manufacture, handing, and distribution. Keywords: Domiati, E. coli virulence genes, Mish, Ras, S. aureus enterotoxins.

IDENTIFICATION OF BIRD EMBRYO PALLOROSIS BY BIOLOGICAL CONTROL OF INCUBATION EGG

The article presents comparative production experiments to identify pallorosis-salmonellosis of chicken embryos of the egg cross «Rhodonit 3», «High Sex Brown», and «Brown Nick». Autopsy of unhatched incubation eggs of chickens revealed that in 15–18 % of dead embryos, the contents of the yolk 73 sac were grassy-green in color and injected with a network of blood vessels of dense consistency. The gallbladder is enlarged several times and is filled with thick viscous dark green bile, which permeates the liver from the inside. On the body of the embryos and allantois membranes, the deposition of uric acid salts. In birds that died from salmonellosis, a sizeable unused yolk the size of a nut, catarrhal-hemorrhagic inflammation of the gastrointestinal tract was observed. The blind processes of the intestine are filled with a fibrinous mass; there is an ampoule-like expansion of the rectum, filled with gases and uric acid salts. It is advisable to combat the salmonellosis of birds: the implementation of organizational, sanitary-hygienic and therapeutic measures, serological identification of birds. In these cases, the only way out is the rational use of reliable and safe antibacterial agents, primarily antibiotics.

Serological identification of SARS-CoV-2 infections among children visiting a hospital during the initial Seattle outbreak

Children are strikingly underrepresented in COVID-19 case counts1–3. In the United States, children represent 22% of the population but only 1.7% of confirmed SARS-CoV-2 cases1. One possibility is that symptom-based viral testing is less likely to identify infected children, since they often experience milder disease than adults1,4–7. To better assess the frequency of pediatric SARS-CoV-2 infection, we serologically screened 1,775 residual samples from Seattle Children′s Hospital collected from 1,076 children seeking medical care during March and April of 2020. Only one child was seropositive in March, but seven were seropositive in April for a period seroprevalence of ≈ 1%. Most seropositive children (6/8) were not suspected of having had COVID-19. The sera of seropositive children had neutralizing activity, including one that neutralized at a dilution >1:18,000. Therefore, an increasing number of children seeking medical care were infected by SARS-CoV-2 during the early Seattle outbreak despite few positive viral tests.