Evaluation of the effect of Saccharomyces cerevisiae on the expression of enterotoxin genes in Escherichia coli O157: H7 (EHEC) and Escherichia coli H10407 (ETEC).

Enterotoxigenic (ETEC) and enterohemorrhagic Escherichia coli (EHEC) are the most important intestinal pathogens. Probiotics play an effective role in reducing the expression of virulence factor genes in intestinal pathogenic bacteria. The aim of the present study is to investigate the effect of probiotic Saccharomyces cerevisiae S3 on the expression of enterotoxin genes in both ETEC and EHEC. Supernatant and lysate of S. cerevisiae S3 are prepared. Subminimal inhibitory concentrations (sub-MIC) of supernatant and lysate are individually exerted to O157: H7 and H10407. The genes' expression of enterotoxins (elt, est, stx1, and stx2) are then determined using real-time PCR technique. The results showed, the yeast supernatant could decrease the expression of the elt gene in ETEC and that of stx1 in EHEC. Of note, in other cases, stx1 and est genes' expression increased. The lysate had no inhibitory effect on the expressions of elt, est, and stx2 genes, but it increased the expression of genes in both ETEC and EHEC. Lysate extract only decreased the expression of stx1 in O157: H7. Our study shows some interesting results regarding the effectiveness of the compounds produced by S. cerevisiae S3 in the expressions of toxin genes in both ETEC and EHEC. We recommend more similar studies be performed in this regard.

Involvement of Pseudomonas aeruginosa in the occurrence of community and hospital acquired diarrhea, and its virulence diversity among the stool and the environmental samples.

Transmission of Pseudomonas aeruginosa along the food chain could cause gastrointestinal infections. To show this involvement, the prevalence, putative virulence genotype, and antibiotic resistance phenotype of P. aeruginosa isolates from stool of 1482 patients with community and hospital acquired diarrhea were compared with 87 isolates from the environmental samples. The results showed infection with P. aeruginosa in 3.4% of the cases, while 57.4% of vegetable samples were contaminated. Significantly higher frequency of lasB (98%), aprA (98%), exoY (98%), and exoS (90%), but lower rate of exoT (39.2%), was detected among the stool isolates. Multi-drug resistance (MDR) phenotype was detected in 25.5% and 4% of the stool and vegetable isolates, respectively. A higher rate of studied virulence genes was detected among the MDR strains vs non-MDR strains. These results indicate P. aeruginosa as a causative agent of diarrhea either among the hospitalized patients and those with community-acquired diarrhea.

The global prevalence of Chlamydia pneumoniae, Helicobacter pylori, Cytomegalovirus and Herpes simplex virus in patients with coronary artery disease: A systematic review and meta-analysis.

BACKGROUND AND AIM: Coronary Artery Disease (CAD) is one of the most important causes of death worldwide. The aim of this study was to determine the prevalence of C. pneumoniae, H. pylori, Cytomegalovirus (CMV) and Herpes simplex virus (HSV) in CAD patients based on published serological and molecular studies. METHODS: A systematic literature search was conducted in Medline (via PubMed), Embase, Scopus and Web of Science databases (1996-2019). Both molecular and serological studies were analyzed using STATA software (Version 14). RESULTS: 145 studies were included for final analysis. We gathered and investigated the prevalence of C. pneumoniae (25.1% [95% confidence interval (CI) 21.5-28.8%]), H. pylori (12.8% [(95% CI) 4.0-22.0%]), CMV (64.4% [(95% CI) 57.7-73.0%]) and HSV (31.8% [(95% CI) 21.5-42.2%]) in CAD patients from the analysis of molecular studies. Additionally, in serological studies, the prevalence of mentioned pathogens were 72.7% [(95% CI) 67.8-77.6%], 63.3% [(95% CI) 60.0-66.5%], 62.2% [(95% CI) 58.0-66.3%] and 34.3% [(95% CI) 23.6-45.1%] respectively. CONCLUSION: Interestingly, there was only a significant increase in the prevalence of C. pneumoniae and H. pylori in serological studies compared to the reported data from molecular studies, while the prevalence of CMV and HSV were the same in both types of studies.

Halophilic Prokaryotes in Urmia Salt Lake, a Hypersaline Environment in Iran.

In this study, fluorescence in situ hybridization (FISH) and PCR-amplified fragments of the 16SrDNA gene were used to determine prokaryotes diversity in Urmia Salt Lake. Prokaryote cell population in Urmia lake range from 3.1 ± 0.3 × 106, 2 ± 0.2 × 108, 4 ± 0.3 × 108, and 1.8 ± 0.2 × 108 cells ml-1 for water, soil, sediment, and salt samples by DAPI (4́, 6-diamidino-2-phenylindole) direct count, respectively. The proportion of bacteria and archaea in the samples determinable by FISH ranged between 36.1 and 55% and 48.5 and 55.5%, respectively. According to the DGGE method, some bands were selected and separated from the gel, then amplified and sequenced. The results of sequences were related to two phyla Proteobacteria (16.6%) and Bacteroidetes (83.3%), which belonged to four genera Salinibacter, Mangroviflexus, Pseudomonas, and Cesiribacter, and the archaeal sequences were related to Euryarchaeota phyla and three genera Halonotius, Haloquadratum, and Halorubrum. According to our results, it seems that prokaryotic populations in this hypersaline environment are more diverse than expected, and bacteria are so abundant and diverse and form the metabolically active part of the microbial population inhabiting this extreme environment. Molecular dependent and independent approaches revealed a different aspect of this environment microbiota.

In silico design of an immunogen against Acinetobacter baumannii based on a novel model for native structure of Outer membrane protein A.

Outer membrane protein A (OmpA) is the most promising vaccine candidate against one of the most successful nosocomial pathogens, A. baumannii. Despite advantages of the antigen, its cytotoxicity could be considered as a challenge in clinical trials. In order to improve this effective immunogen, rational vaccine design strategies such as structure-based vaccinology should be assessed. However, native structure of OmpA remains controversial. The present study is conducted to address the native structure of OmpA; then, a novel immunogen with lower toxicity and higher antigenicity was designed based on structural vaccinology. Various bioinformatic and immunoinformatic tools were harnessed to perform analyses such as topology, secondary structure, and tertiary structure predictions as well as B-cell epitope predictions. A novel 12-stranded model is suggested for OmpA. K320 and K322 were substituted by Alanine, "NADEEFWN" sequence was replaced by "YKYDFDGVNRGTRGTSEEGTL", Position 1-24 at the N-terminus and the C-terminal sequence "VVQPGQEAAAPAAAQ" were removed. The designed construct has more epitope density and antigenic properties with higher immunogenicity while its cytotoxicity is decreased. Moreover, this single cross-protective antigen could trigger antibodies rendering protection against two important nosocomial pathogens i.e. Pseudomonas aeruginosa and A. baumannii.

A conserved region from biofilm associated protein as a biomarker for detection of Acinetobacter baumannii.

Acinetobacter baumannii is the leading cause of nosocominal infection within the family Moraxellaceae. Due to multiple antibiotic resistances of the bacteria, the treatment is very difficult, hence specific and economical test for early diagnosis of infection is needed. Development of such a test requires targeting specific cell surface antigens. Bacterial ability of biofilm formation grants major contribution in antimicrobial resistance and other environmental stresses such as nutrient limitation and dehydration. Biofilm associated protein (Bap), a specific cell surface protein, is directly involved in A. baumannii biofilm formation. The goal of this study is diagnosis of A. baumannii infection exploiting specific target from Bap. A selected subunit of Bap was cloned, expressed and purified. Mice were divided into three groups. Group one was immunized with recombinant Bap subunit, mice in group two were infected with A. baumannii (positive control) and mice in groups three served as negative control. Immunization with Bap subunit resulted in high antibody titers. Animals in control group that received same amount of adjuvant and PBS showed no Bap-specific antibodies. Sensitivity and specificity of the antibodies raised were determined by ELISA and Western blotting. Recombinant Bap subunit was tested by ELISA using sera obtained from A. baumannii infected patients and healthy individuals. This conserved and immunodominant region of Bap could serve as an appropriate target for diagnosis A. baumannii infection.

Evaluation of the Effect of Lactobacillus acidophilus ATCC 4356 Bacteriocin against Staphylococcus aureus.

Background: Lactobacillus acidophilus is lactic acid bacteria that produce bacteriocins. Bacteriocins are antimicrobial peptides or proteins that exhibit activity against closely related bacteria. The aim of this study was to determine the effect of L. acidophilus ATCC 4356 bacteriocin against Staphylococcus aureus. Material and Methods. We used four different phenotypic methods for antimicrobial activities against two standard strains: methicillin-resistant S. aureus (MRSA) ATCC 33591 and methicillin-susceptible S. aureus (MSSA) ATCC 25923. The methods were (1) agar well diffusion, (2) overlay soft agar, (3) paper disk, and (4) modification of punch hole. The ammonium sulfate method was used to concentrate crude bacteriocin, and ultrafiltration and dialysis tubes were used to remove ammonium sulfate from the bacteriocins. Each method was repeated in triplicate. Result: L. acidophilus ATCC 4356 showed antimicrobial activity against both MRSA and MSSA standard strains only by the overlay soft agar method and not by the agar well diffusion, punch hole modification, and paper disk methods. No antimicrobial effects were observed in crude bacteriocins concentrated. Conclusion: The growth inhibition of S. aureus in overlay soft agar method may be due to the production of bacteriocin-like substances. The overlay soft agar method is a qualitative test, so there is a need for further study to optimize the conditions for the production of bacteriocin-like substances in the culture supernatant and precise comparison between the inhibitory activity and pheromone secretion of different strains.

Immune response variations to Salmonella enterica serovar Typhi recombinant porin proteins in mice.

OBJECTIVES: Typhoid fever is caused by Salmonella enterica serovar Typhi. OmpC, OmpF and OmpA, the three major outer membrane proteins (OMPs), could serve as vaccine candidates. METHODS: The porins antigenicity was predicted in silico. The OMP genes were amplified, cloned and expressed. Sero-reactivities of the recombinant proteins purified by denaturing method were assayed by ELISA. BALB/c mice were immunized with the recombinant porins followed by bacterial challenge. RESULTS: Bacterial challenge of the animal model brought about antibody triggering efficacy of the antigen in OmpF > OmpC > OmpA order. Experimental findings validated the in silico results. None of the antigens had synergic or antagonistic effects on each other from immune system induction points of view. Despite their high immunogenicity, none of the antigens was protective. However, administration of two or three antigens simultaneously resulted in retardation of lethal effect. Porins, in addition to their specific functions, share common functions. Hence, they can compensate for each other's functions. CONCLUSIONS: The produced antibodies could not eliminate the pathogenicity by blockade of one or some of the antigens. Porin antigens are not suitable vaccine candidates alone or in denatured forms. Native forms of the antigens maybe studied for protective immunogenicity.

Conjunctival microbial florae in patients with seriously sulfur mustard induced eye injuries.

INTRODUCTION: Ocular surface disorders and infections in sulfur mustard (SM) exposed patients are of particular clinical importance. The aim of the present study is to detect the conjunctival bacterial florae in patients with seriously SM induced eye injuries. MATERIALS AND METHODS: Conjunctival bacterial florae of 143 seriously eye injured subjects as the study group was detected. The results were compared with 26 normal participants. Both groups were matched in age and sex. The samples were taken by sterile swab from interior fornixes of conjunctiva in both groups and were transported to microbiology laboratory by Stuart's Transport Medium. All samples were inoculated onto Blood agar, Mac Conkey agar and Chocolate agar and isolated microorganisms were identified by biochemical tests. The data were analyzed by SPSS and Man Whitney tests. RESULTS: Nineteen cases (13.39%) and none of the controls (0%) had positive culture results (p = .043). Isolated microorganisms from patients included coagulase-negative staphylococci 10 cases (52.6%), Staphylococcus aureus 5 cases (26.3%), non enterobacteriaceae gram negative bacilli 2 cases (10.5%), Penicillium spp. 2 cases (10.5%), Citrobacter sp. 1 case (5.2%), non-spore forming Gram positive bacillus 1 case (5.2%) and α hemolytic streptococcus 1 case (5.2%). Two patients had mixed microorganisms and other patients had just one microorganism. Most of the S. aureus isolates were sensitive to usual antibiotics. CONCLUSIONS: The results of this study showed that the prevalence rate of conjunctival bacterial isolates in patients with seriously SM induced ocular injuries are higher and potentially more dangerous than normal controls.

A clinicopathological approach to sulfur mustard-induced organ complications: a major review.

CONTEXT: Sulfur mustard (SM), with an old manufacturing history still remains as potential threat due to easy production and extensive effects. OBJECTIVES: Increasing studies on SM indicates the interest of researchers to this subject. Almost all human body organs are at risk for complications of SM. This study offers organ-by-organ information on the effects of SM in animals and humans. METHODS: The data sources were literature reviews since 1919 as well as our studies during the Iraq-Iran war. The search items were SM and its all other nomenclatures in relation to, in vivo, in vitro, humans, animals, eye, ocular, ophthalmic, lungs, pulmonary, skin, cutaneous, organs and systemic. Amongst more than 1890 SM-related articles, 257 more relevant clinicopathologic papers were selected for this review. RESULTS: SM induces a vast range of damages in nearly all organs. Acute SM intoxication warrants immediate approach. Among chronic lesions, delayed keratitis and blindness, bronchiolitis obliterans and respiratory distress, skin pruritus, dryness and cancers are the most commonly observed clinical sequelae. CONCLUSION: Ocular involvements in a number of patients progress toward a severe, rapid onset form of keratitis. Progressive deterioration of respiratory tract leads to "mustard lung". Skin problems continue as chronic frustrating pruritus on old scars with susceptibility to skin cancers. Due to the multiple acute and chronic morbidities created by SM exposure, uses of multiple drugs by several routes of administrations are warranted.

Effects of Sub-Minimum Inhibitory Concentrations of Gentamicin on Alginate Produced by Clinical Isolates of Pseudomonas aeruginosa.

Background: Bacterial virulence factors may be influenced by sub-minimum inhibitory concentrations (sub-MICs) of antibiotics. The main purpose of this study was to investigate the effects of gentamicin at sub-MICs (0.5 MIC and 0.25 MIC) on alginate production of clinical isolates of Pseudomonas aeruginosa. Materials and Methods: The minimum inhibitory concentrations of gentamicin against 88 clinical isolates of P. aeruginosa were determined using the broth microdilution method. Alginate production of the isolates in the absence and presence of gentamicin at sub-MICs was assessed by the carbazole method. The presence of alginate in clinical isolates was confirmed by the detection of alginate genes (algD and algU) using the PCR method. Results: All the isolates had the ability of alginate production and were positive for algD and algU genes. sub-MICs of gentamicin significantly increased alginate production of 34 isolates (38.6%). On the other hand, in 49 isolates (55.7%), alginate production was significantly increased after treatment with sub-MICs of gentamicin. In five isolates (5.7%), the alginate production was reduced in exposure to 0.5 MIC of gentamicin while it was increased by gentamicin at 0.25 MIC. Conclusion: This study showed different effects of gentamicin at sub-MICs on the alginate production of clinical isolates of P. aeruginosa. Further research is highly recommended to understand the mechanism of different responses of P. aeruginosa isolates to the exposure of sub-MICs of gentamicin.

Anti-Biofilm Potential of Lactobacillus casei and Lactobacillus rhamnosus Cell-Free Supernatant Extracts against Staphylococcus aureus.

Background: Biofilm production is an important virulence factor in Staphylococcus aureus. Most of the infections associated with biofilms of this bacterium are very difficult to treat using antibiotics. The present research studied the effects of the two probiotic Lactobacillus species L. casei and L. rhamnosus on S. aureus biofilm. Materials and Methods: Cell-free supernatant (CFS) extracts of L. casei ATCC 39392 and L. rhamnosus ATCC 7469 culture were prepared. The effects of sub-minimum inhibitory concentrations of the CFS extracts on cell surface hydrophobicity (CSH), initial attachment, biofilm formation, and their ability in eradicating S. aureus ATCC 33591 biofilms were assessed. In addition, the effects of CFS extracts on expression of the genes involved in formation of S. aureus biofilms (cidA, hld, sarA, icaA, and icaR) were also evaluated through real-time polymerase chain reaction. Results: CFSs of both Lactobacillus spp. significantly reduced CSH, initial attachment, and biofilm formation and eradicated the biofilms. The above findings were supported by scanning electron microscopy results. These two Lactobacillus CFSs significantly changed the expression of all studied biofilm-related genes. Expression levels of cidA, hld, and icaR genes significantly increased by 4.4, 2.3, and 4.76 fold, respectively, but sarA and icaA genes were significantly downregulated by 3.12 and 2.3 fold. Conclusion: The results indicated that CFS extracts of L. casei and L. rhamnosus had desirable antagonistic and anti-biofilm effects against S. aureus. Consequently, carrying out further research enables us to prepare pharmaceuticals from these CFSs in order to prevent and treat infections caused by S. aureus biofilms.

Antimicrobial Effects of Mouse Adipose-Derived Mesenchymal Stem Cells Encapsulated in Collagen-Fibrin Hydrogel Scaffolds on Bacteroides fragilis Wound Infection in vivo.

Background: Anaerobes are the causative agents of many wound infections. B. fragilis is the most prevalent endogenous anaerobic bacterium causes a wide range of diseases, including wound infections. This study aimed to assess the antibacterial effect of mouse adipocyte derived-mesenchymal stem cell (AD-MSCs) encapsulated in collagen-fibrin (CF) hydrogel scaffolds on B. fragilis wound infection in an animal model. Methods: Stem cells were extracted from mouse adipose tissue and confirmed by surface markers using flow cytometry analysis. The possibility of differentiation of stem cells into osteoblast and adipocyte cells was also assessed. The extracted stem cells were encapsulated in the CF scaffold. B. fragilis wound infection was induced in rats, and then following 24 h, collagen and fibrin-encapsulated mesenchymal stem cells (MSCs) were applied to dress the wound. One week later, a standard colony count test monitored the bacterial load in the infected rats. Results: MSCs were characterized as positive for CD44, CD90, and CD105 markers and negative for CD34, which were able to differentiate into osteoblast and adipocyte cells. AD-MSCs encapsulated with collagen and fibrin scaffolds showed ameliorating effects on B. fragilis wound infection. Additionally, AD-MSCs with a collagen scaffold (54 CFU/g) indicated a greater effect on wound infection than AD-MSCs with a fibrin scaffold (97 CFU/g). The combined CF scaffold demonstrated the highest reduction in colony count (the bacteria load down to 29 CFU/g) in the wound infection. Conclusion: Our findings reveal that the use of collagen and fibrin scaffold in combination with mouse AD-MSCs is a promising alternative treatment for B. fragilis.

The Relationship between the Biofilm Genes and Antibiotic Resistance in Stenotrophomonas maltophilia.

Objectives: Today, Stenotrophomonas maltophilia (S. maltophilia) is a major opportunistic pathogen among hospitalized or immunocompromised patients. Antibiotic-resistant clinical isolates are increasing in several parts of the world. Various antibiotic-resistance and biofilm-forming genes are identified in this bacterium. Its capacity to form biofilms is an important virulence factor that may impact antibiotic-resistance patterns. In the current study, we evaluated the biofilm-formation capacity, antibiotic-resistance profile, and prevalence of biofilm-forming genes as well as antibiotic resistance genes among S. maltophilia isolates. Materials and Methods: In this cross-sectional study, 94 clinical S. maltophilia isolates were recovered from four tertiary-care hospitals in Iran between 2021 and 2022. The presence of the selected antibiotic-resistance genes and biofilm-forming genes was examined by polymerase chain reaction (PCR). The ability of biofilm formation was examined by microtiter plate assay. The Kirby-Bauer disc diffusion method was used to evaluate the trimethoprim-sulfamethoxazole (TMP-SMX), levofloxacin, and minocycline resistance. Results: S. maltophilia is mainly isolated from bloodstream infections. Notably, 98.93% of isolates were biofilm producers, of which 19.35%, 60.22%, and 20.43% produced strong, moderate, and weak biofilm, respectively. The frequency of biofilm genes was 100%, 97.88%, 96.80%, and 75.53% for spgM, rmlA, smf-1, and rpfF, respectively. Isolates with the genotype of smf-1+/rmlA+/spgM+/rpfF+ were mostly strong biofilm producers. Among the antibiotic-resistance genes, the Smqnr, L1, and sul1 had the highest prevalence (76.59%, 72.34%, and 64.89), respectively. Antimicrobial susceptibility evaluation showed 1.06%, 3.19%, and 6.3% resistance to minocycline, TMP-SMX, and levofloxacin. Conclusion: The results of the current study demonstrated that S. maltophilia isolates differ in biofilm-forming ability. Moreover, smf-1, rmlA, and spgM genes were presented in all strong biofilm producers. Although the overall resistance rate to the evaluated antibiotics was high, there was no statistically significant relation between antibiotic resistance and the type of biofilm.

Clinical efficacy of probiotics in prevention of infectious diseases among hospitalized patients in ICU and non-ICU wards in clinical randomized trials: A systematic review.

Background and Aims: The present study aimed to review probiotics' clinical efficacy in preventing infectious diseases among hospitalized patients in ICU and non-ICU wards. Methods: A search of Medline, EMBASE, The Cochrane Library, Science Direct, Open Grey, and Google Scholar was conducted for eligible publications from 2002 to 2020 following the requirements outlined in the PRISMA guideline. The search strategy was based on the combination of the following terms: "probiotics," "prebiotics," "synbiotics," and "cross-infection." The logical operators "AND" (or the equivalent operator for the databases) and "OR" (e.g., probiotics OR prebiotics OR synbiotics) were used. Results: The results indicated that the probiotic consumption caused a significant reduction in antibiotic-associated diarrhea (AAD) and Clostridioides difficile infection (CDI) in 2/8 randomized clinical trials (RCTs) investigating AAD/CDI. Also, 5/12 clinical trials highlighted the considerable effects of probiotics on the reduction or prevention of ventilator associated pneumoniae (VAP), so the mean prevalence of VAP was lower in the probiotic group than in the placebo group. The total rate of nosocomial infections among preterm infants was nonsignificantly higher in the probiotic group compared to the control group. Conclusion: This systematic review shows that the administration of probiotics has moderate preventive or mitigating effects on the occurrence of VAP in ICU patients, CDI, AAD, and nosocomial infections among children. Consequently, applying antibiotics along with the proper probiotic species can be advantageous.

Determination of principal genotypic groups among susceptible, MDR and XDR clinical isolates of Mycobacterium tuberculosis in Belarus and Iran.

INTRODUCTION: All members of the Mycobacterium tuberculosis complex were assigned to one of the three principle genetic groups based on KatG463/GyrA95 polymorphism. MATERIALS AND METHODS: A total of 202 isolates of M. tuberculosis consisting of 50 susceptible, 121 MDR (multidrug resistant) and 31 XDR (extensively drug resistant) isolated from culture-confirmed tuberculosis patients in different regions of Belarus and Iran (Tehran and Markazi province). Isolates were screened by sequencing and polymerase chain reaction restriction fragment length polymorphism (RFLP) assay, and were further divided into three principal genetic groups (PGG), based on Sreevatsan's pattern as polymorphisms in KatG463/GyrA95 codons. RESULTS: Among the 104 isolates, characterized as MDR from Belarus, 57 (54.8 ± 4.8%), 30 (28.8 ± 4.43%), 17 (16.3 ± 3.6), belonged to PGG 1, 2, and 3, respectively (p< 0.05). Thirty one XDR isolates from Belarus had a similar pattern as 15 (48.4%), 12 (38.7%), 4 (12.9%) PGG 1, 2, and 3, respectively. From Iranian samples, Markazi isolates (susceptible to drugs) had a pattern as 12 (36.5%), 15 (45.5%), 3 (6%), and Tehran samples were (selected MDR): 9 (53%), 6 (35.2%), 2 (11.8%) (PGG 1, 2, and 3, respectively). In a study of tuberculosis patients, who were in prison, no relation was found between PGG and resistance to isoniazid, but most of the identified isolates belonged to PGG 1 (45.5 ± 10.9%) (p< 0.05). Overall, the group 1 isolates showed more frequency in MDR and XDR rather than susceptible strains, and there aren't any relations to geographic region.

Prevalence, species diversity, and antimicrobial susceptibility of Campylobacter strains in patients with diarrhea and poultry meat samples: one-year prospective study.

Background and Objectives: Source tracking of antimicrobial resistance in Campylobacter is useful for control measures. In this study, Campylobacter-associated diarrhea and homology in antimicrobial resistance of humans and poultry meat isolates were investigated. Materials and Methods: A total of 400 stools of patients and 100 poultry meat samples were analyzed. Susceptibility of the isolates was detected by disk diffusion, Etest, and agar dilution methods. Mismatch amplification mutation assay was used for the detection of mutations in the gyrA quinolone resistance determining region (QRDR). Results: Campylobacter spp., including C. jejuni, C. coli, and C. lari, were detected in 35% of the chicken meat and 6.75% of the stool samples, respectively. The QRDR mutation was detected in most of the stool and chicken meat samples. Although the frequency of resistance to tetracycline (53.5% and 62.8%), erythromycin (39.2% and 37.1%), and gentamicin (32.1% and 31.4%) was relatively similar, higher frequency of resistance to ciprofloxacin (51.4% vs 28.6%) and nalidixic acid (42.15% vs 28.6%) among the chicken meat, and ampicillin (50% and 17.1%) among the human stool was detected. Conclusion: High percentage of poultry meat samples is contaminated with different Campylobacter species, which shows homology with the patients' isolates in Tehran.

Vaccination with a combination of planktonic and biofilm virulence factors confers protection against carbapenem-resistant Acinetobacter baumannii strains.

Acinetobacter baumannii is a multi-drug resistant pathogen with the ability to switch between planktonic and biofilm phenotypes. Although there is no vaccine against A. baumannii infections, many attempts have been made to develop vaccines using planktonic or biofilm antigens. To cover the different phenotypes of A. baumannii during growth and attachment, we combined planktonic upregulated antigens of iron receptors with biofilm upregulated antigens of pilus rods and evaluated immune responses and protective efficacies of the combined vaccine using lethal and sub-lethal murine sepsis models. The results showed that the combined vaccine elicited high IgG antibody titers and conferred protection against lethal doses of two Carbapenem-resistant high adherent A. baumannii strains. Complete bacterial clearance from all the affected tissues of the mice challenged with A. baumannii was an excellent achievement with our quadrivalent immunogen. These results demonstrate both planktonic and biofilm antigens are important during antigen selection for vaccine design.

Pseudomonas aeruginosa PAO1 outer membrane vesicles-diphtheria toxoid conjugate as a vaccine candidate in a murine burn model.

Pseudomonas aeruginosa is an opportunistic pathogen considered a common cause of nosocomial infection with high morbidity and mortality in burn patients. Immunoprophylaxis techniques may lower the mortality rate of patients with burn wounds infected by P. aeruginosa; consequently, this may be an efficient strategy to manage infections caused by this bacterium. Several pathogenic Gram-negative bacteria like P. aeruginosa release outer membrane vesicles (OMVs), and structurally OMV consists of several antigenic components capable of generating a wide range of immune responses. Here, we evaluated the immunogenicity and efficacy of P. aeruginosa PA-OMVs (PA-OMVs) conjugated with the diphtheria toxoid (DT) formulated with alum adjuvant (PA-OMVs-DT + adj) in a mice model of burn wound infection. ELISA results showed that in the group of mice immunized with PA-OMVs-DT + adj conjugated, there was a significant increase in specific antibodies titer compared to non-conjugated PA-OMVs or control groups. In addition, the vaccination of mice with PA-OMVs-DT + adj conjugated generated greater protective effectiveness, as seen by lower bacterial loads, and eightfold decreased inflammatory cell infiltration with less tissue damage in the mice burn model compared to the control group. The opsonophagocytic killing results confirmed that humoral immune response might be critical for PA-OMVs mediated protection. These findings suggest that PA-OMV-DT conjugated might be used as a new vaccine against P. aeruginosa in burn wound infection.