Molecular Typing of Multidrug-Resistant Acinetobacter baumannii Isolates from Clinical Specimens by ERIC-PCR and MLVA.

Acinetobacter baumannii, a Gram-negative and oxidase-negative bacterium, is a major cause of nosocomial infections, leading to high mortality rates in hospitalized patients. The use of 2 prominent molecular typing methods (i.e., enterobacterial repetitive intergenic consensus-polymerase chain reaction [ERIC-PCR] and multiple-locus variable-number tandem repeat [VNTR] analysis [MLVA]) for genotyping A. baumannii isolates has proven to be an effective approach in assessing the clonal relation of these isolates and managing their outbreaks. A total of 100 A. baumannii isolates were collected from immunocompromised patients hospitalized in the intensive care unit (ICU) of a hospital in Zanjan City, Iran. Their antibiotic resistance ability (especially aminoglycoside resistance) was studied by disc diffusion tests. The genetic typing of A. baumannii was studied using ERIC-PCR and MLVA methods. All isolates were resistant to 3 or more antibiotics and regarded as multidrug-resistant (MDR). Additionally, 32% of the isolates were resistant to all antibiotics tested, and 91% were extensively drug-resistant (XDR). The increased rate of aminoglycoside-resistant A. baumannii in ICU patients, with an increased incidence of aminoglycoside-modifying enzymes of aac (6')-Ib, ant (3″)-I, and aph (2″)-Id. ERIC-PCR has likewise shown an increased level of diversity in A. baumannii isolates. According to the ERIC-PCR patterns, isolates were classified as 4 clusters, while according to the MLVA patterns, isolates were classified as 9 distinct clusters. ERIC-PCR and MLVA assays serve as useful genotyping methods to assess the genetic variety or clonal relatedness of A. baumannii isolates.

Immunogenic Evaluation of MPEG-PCL & PLGA Nanoparticles Containing Klebsiella pneumoniae K2O1 Capsular Antigen in Pulmonary Infection Model of Mice.

Klebsiella pneumoniae can cause destructive changes to human lungs if aspirated. The present study aimed to evaluate the immunogenicity of the carriers of Poly lactic-co-glycolic acid (PLGA) and Methoxypoly(ethylene glycol) Poly(caprolactone) (MPEG-PCL) nanoparticles containing the capsular antigen of Klebsiella pneumoniae K2O1 in a model of pulmonary infection in mice as a vaccine candidate. Capsule antigen was extracted from K.pneumoniae K2O1 strain 1053 ATCC 10031 and transported with PLGA or MPEG-PCL nanoparticles as a vaccine in an animal model. The results of FT-IR and AFM confirmed the presence of antigen functional groups in the nanoparticle structure, and semi-spherical shape of the nanoparticles, respectively. The capsular polysaccharide was also used to evaluate the febrileness of the designed vaccine candidates based on the rabbits' pattern, and mortality due to the vaccine candidates in the mice. No fever was observed, and no mortality was observed in the mice. According to the results, the vaccine candidates designed to control the cause of pulmonary infections were effective in the liver, spleen, and lungs of the animals with the ability to enter the first stage of the clinical trial phase.

Hospital wastewater treatment using eco-friendly eugenol nanostructured lipid carriers: Formulation, optimization, and in vitro study for antibacterial and antioxidant properties.

In this study, nano-formulation has been used to tackle one of the most important environmental problems which can be considered a major threat to human health. We prepared some eco-friendly nanostructured lipid carriers (NLCs) as delivery agents to properly deliver an antibacterial agent (eugenol) into hospital wastewater in order to control bacterial growth. Eugenol-loaded nanostructured lipid carriers were prepared by hot high-speed homogenization. Then, the prepared nanocarriers were characterized using different techniques such as transmission electron microscopy, Fourier transform infrared, and dynamic scanning calorimetry. The turbidity assay and colony counting method were used to determine the ability of the prepared eugenol-loaded nanostructured lipid carriers to inhibit bacterial growth rate in the culture media and hospital wastewater, respectively. The mean size and zeta potential of NLC-eugenol were 78.12 ± 6.1 nm and -29.43 ± 2.21 mV, respectively. The results showed that the highest inhibitory effect of NLC-eugenol in culture media was seen in standard and wild Staphylococcus aureus strains (43.42% and 26.41%, respectively) with a concentration of 0.125 µM. The antibacterial activity of NLC-eugenol in sterile wastewater on wild strains of bacteria showed that the most effective concentration to reduce bacterial amounts was 0.125 µM on wild S. aureus and Enterococcus faecalis strains (38% and 33.47%, respectively) at 37°C. The NLC-eugenol with a concentration of 0.125 µM showed the greatest effect of reducing total microbial agents by 28.66% in hospital wastewater at 25°C. The highest antibacterial effect achieved using the 0.125 µM concentration is due to the egel phenomenon. Also, the mechanism of action of NLC-eugenol is cell wall destruction and eventually cell death. The results showed that NLC-eugenol with a concentration of 0.125 µM can reduce wild bacterial strains in sterilized wastewater and hospital wastewater, which can prove the great potential of the prepared eugenol-loaded nanostructured lipid carriers to control bacterial growth. PRACTITIONER POINTS: NLC is one of the safest biodegradable and environmentally friendly carriers, which is nontoxic for humans and the environment. Eugenol is a natural compound, which makes it less toxic for the environment while being toxic for bacteria. Therefore, our method has the least side effect in comparison with existing methods for wastewater treatment. The gradual release of eugenol from NLC nanoparticles can effectively control the pathogenic factors of wastewater.

Genetic diversity of colistin resistance Nosocomial Acinetobacter baumannii strains from Iran.

BACKGROUND: Drug-resistant Acinetobacter baumannii is a global health problem since its ability to acquire new resistance mechanisms. Here, we aimed to determine the association of common types of A. baumannii and assess their drug resistance of A. baumannii and contribution of integrons (Ints) and oxacillinase genes in Zanjan, Iran. MATERIALS AND METHODS: Among 68 isolated Acinetobacters from patients, 48 isolates were A. baumannii strains. Antibiotic susceptibility pattern and colistin resistance were determined by disk diffusion and broth microdilution, respectively. The presence of Int I, II, III, and oxacillinase genes examined using polymerase chain reaction. The clonal relationship of clinical isolates of A. baumannii determined by Pulsed Field Gel Electrophoresis method. RESULTS: The results showed the highest antibiotic susceptibility (58%) for colistin. 96% of isolates were considered as multidrug resistant, and 46% as extensively drug resistant, and 16% as pandrug resistant. Frequencies of Int I, II, III resistance genes were 60%, 28%, and 0%, respectively, and 12% of strains had no isoform of Ints. Frequencies of Carbapenem resistance genes were 74%, 24%, 100%, and 4% for blaOXA-23, blaOXA-24, blaOXA-51, and blaOXA-58, respectively. The above samples were group into 26 pulsotypes. CONCLUSION: The studied A. baumannii strains had several resistance genes, and the colistin resistance showed an extraordinary ascending tendency that could be a severe issue in nosocomial infections, and the presence of high genetic diversity indicated a variation in A. baumannii strains and possibly a variety of sources of contamination or infection.

Genotypic and phenotypic analysis of biofilm formation Staphylococcus epidermidis isolates from clinical specimens.

OBJECTIVES: Staphylococcus epidermidis is the primary causative agent of infections associated with indwelling biomaterials. Antibiotic susceptibility patterns, Biofilm formation capability, and screening of responsible genes in biofilm formation procedure in clinical isolates (icaA, icaB, icaC, icaD, sdrG, and atlE) were assigned as the main objectives in this study. The clinical samples were analyzed via standard biochemical assays for identifying different bacteria which were confirmed using the multiplex colony PCR method. Subsequently, biofilm-formation capability, antibiotic susceptibility testing, and the frequency of genes responsible for biofilm formation in the confirmed strains were checked. RESULTS: Out of 183 clinical specimens 54 S. epidermidis isolates were detected by targeting a housekeeping gene (sesc) taking advantage of the PCR procedure. All of the strains were Biofilm forming producers. The in vitro biofilm formation assays determined that 45 (83.33%), 5 (9.26%), 4 (7.41%) were strong, moderate, and weak biofilm former strains respectively. Among the isolated strains, the specific frequencies of the biofilm-forming genes were specified to be (98%) for sdrG, (84%) for atlE, (80%) for icaC, and (70%) for icaD. Cefamandole and Amikacin are the most effective antibiotics in isolated strains. All strains were ascertained to be methicillin and amoxicillin/clavulanic acid resistant.

Virulence characteristics of multidrug resistant biofilm forming Acinetobacter baumannii isolated from intensive care unit patients.

BACKGROUND: Nosocomial infections and persistence of multidrug resistant biofilm forming Acinetobacter baumannii in hospitals has made it as a serious problem in healthcare settings worldwide. METHODS: A total of 100 A. baumannii clinical isolates from immunocompromised patients hospitalized in ICU were investigated for biofilm formation, the presence of biofilm related genes (bap, ompA, csuE, fimH, epsA, blaPER-1, bfmS, ptk, pgaB, csgA, kpsMII), integron characterization and molecular typing based on REP-PCR. RESULTS: All isolates were resistant to three or more categories of antibiotics and considered as multidrug resistant (MDR). A total of 32 isolates were resistant to all tested antibiotics and 91% were extensively drug-resistance (XDR). All isolates were able to produce biofilm and 58% of isolates showed strong ability to biofilm formation. All strong biofilm forming A. baumannii isolates were XDR. All A. baumannii isolates carried at least one biofilm related gene. The most prevalent gene was csuE (100%), followed by pgaB (98%), epsA and ptk (95%), bfmS (92%) and ompA (81%). 98% of isolates carried more than 4 biofilm related genes, simultaneously. Class I integron (67%) was more frequent in comparison with class II (10%) (P < 0.05). The REP-PCR patterns were classified as 8 types (A-H) and 21 subtypes. The A1 (23%) and C1 (15%) clusters were the most prevalent among A. baumannii isolates (P < 0.05). According to the REP-PCR patterns, 23% of all isolates had a clonal relatedness. CONCLUSION: Our study revealed the high frequency of biofilm forming XDR A. baumannii in ICU patients, with a high prevalence of biofilm related genes of csuE and pgaB. It seems that the appropriate surveillance and control measures are essential to prevent the emergence and transmission of XDR A. baumannii in our country.

Exotoxin A-PLGA nanoconjugate vaccine against Pseudomonas aeruginosa infection: protectivity in murine model.

Pseudomonas aeruginosa is the major infectious agent of concern for cystic fibrosis (CF) patients. Therefore, it is necessary to develop appropriate strategies for preventing colonization by this bacterium and/or neutralizing virulence factors. In this study, we formulated the encapsulation of exotoxin A into PLGA nanoparticles. The biological activities of the nanovaccine candidate were also characterized. Based on the results, ETA-PLGA can act as a suitable immunogen to stimulate the humoral and cellular immune response. The antibodies raised against ETA-PLGA significantly decreased bacterial titer in the spleens of the immunized mice after challenge with PAO1 strain, compared to the control groups. The encapsulation of PLGA into ETA led to a significantly higher production of INF-γ, TNF-α, IL-4, and IL-17A cytokine responses compared to the ETA group. ETA-PLGA enhanced IgG responses in immunized mice compared to ETA antigen. We concluded that encapsulation of Pseudomonas aeruginosa ETA to PLGA nanoparticles can increase its functional activity by decreasing the bacterial dissemination.

Determining the Biofilm Forming Gene Profile of Staphylococcus aureus Clinical Isolates via Multiplex Colony PCR Method.

BACKGROUND: Among hospitalized patients, Staphylococcus aureus (S. aureus) infections pose a serious health threat. The present study investigated the frequency of biofilm forming genes among clinical isolates S. aureus and their susceptibility to antibiotics. METHODS: The clinical samples were analyzed via standard biochemical assays for identifying different bacterium, which was then confirmed using the multiplex colony PCR method. Those samples identified as S. aureus were examined for the presence of the cna, fnbA, fnbB and pvl genes. The antibiotic susceptibility of the S. aureus isolates was then tested. RESULTS: Using the standard biochemical assay approach, 54 S. aureus strains were identified. However, when using the multiplex PCR method 50 S. aureus strains were identified among the clinical samples. The in vitro biofilm formation assays determined 3 (6%) strains of S. aureus to be strong biofilm forming, 15 (30%) of the isolates were determined to be moderate biofilm forming and, 32 (64%) were determined to be weak biofilm forming. Among the isolated strains, the specific frequencies of the biofilm forming genes were determined to be 31 (62%) for cna, 35 (70%) for fnbA, 13 (26%) for fnbB and 1 (2%) for pvl. In 11 (22%) of the isolated strains fnbA, fnbB and cna genes were all present. All strains were determined to be penicillin, amoxicillin and clavulanic acid resistant. CONCLUSION: Due to the increase of the antibiotic resistance in biofilm producing S. aureus strains, rapid identification of antibiotic resistance can help to eliminate the infection effectively.

Anti-tumor effects of propranolol: Adjuvant activity on a transplanted murine breast cancer model.

Propranolol (Pro), a non-specific ß-adrenergic blocking drug, competitively prevents the binding of catecholamines to receptors and suppresses cancer cells. The anti-tumor activity of propranolol has been proved in different kinds of cancers. In this study, we assessed the adjuvant activity of propranolol combined with a tumor vaccine model on the immunological parameters of breast tumor-bearing mice. Breast tumor pieces were implanted into the flank of inbred BALB/C female mice from stock mice. Tumor-bearing mice were treated with tumor antigen lysate vaccine and propranolol/Vaccine (Pro/Vac) combination (as treatment groups), propranolol and PBS (as control groups) for 5 consecutive days, every 12 h. Moreover, all experimental groups received vaccine for three times with one-week interval via s.c injection. After immunization courses, spleens of tumor-bearing mice were removed and dissected, cell suspension was stimulated in vitro, and the cytokine levels in supernatant of splenocytes were measured via commercial ELISA kits. Compared with the vaccine group, immunization with tumor lysate in combination with propranolol significantly increased IL-2, IL-4, IL-12, IL-17, and IFN-γ cytokines. Considering the suppression of tumor growth, propranolol seems to be a potent immunomodulator capable of inducing cellular immune responses against breast cancer.

Immunological consequences of immunization with tumor lysate vaccine and propranolol as an adjuvant: A study on cytokine profiles in breast tumor microenvironment.

In this study, we sought out to study the anti-cancer effects of propranolol (Pro) in combination with tumor lysate vaccine on lymphocyte proliferation activities as well as on IL-2, IL-4, IL-10, IL-12, IL-17 and IFN-γ cytokine concentration in the tumor microenvironment (TME). A tumor model was established in inbred Balb/C mice using transplantation of tumor to the flank of native mice. Tumor-bearing mice were immunized with lysate tumor cells (vaccine), a combination of Pro/Vaccine (Vac). Control groups consisted of tumor-bearing mice receiving only propranolol or PBS three times with one week interval via subcutaneous (s.c) injection. One week after the last immunization, tumor was removed, homogenate was prepared and the levels of IL-12, IL-17, 1L-2, IL-10, IL-4, IFN-γ cytokine concentrations were evaluated by commercial ELISA kits. In addition, spleen cell suspension was used for the lymphocyte proliferation assay using the BrdU method. Results from this study indicated that Pro/Vac had the ability to significantly increase lymphocyte proliferation, and to suppress tumor growth. Administration of breast tumor lysates with propranolol increased the concentration of IL-12, IL-17, 1L-2 and IFN-γ cytokines in tumor microenvironment. This study has proved the efficiency of propranolol as an adjuvant in combination with the tumor vaccine model on tumor suppression via cytokine pattern modulation in tumor microenvironment.

Synergistic Antibacterial Activity of Plant Peptide MBP-1 and Silver Nanoparticles Combination on Healing of Infected Wound Due to Staphylococcus aureus.

BACKGROUND: Wound infection is a common problem in hospitals and is typically caused by the antibiotic-resistant Staphylococcus aureus, which is a major pathogen for skin and soft tissue infections worldwide. OBJECTIVES: The aim of this study was to investigate the synergistic antibacterial effect of plant peptide MBP-1 and silver nanoparticles on infected wounds caused by S. aureus. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of MBP-1 and silver nanoparticles both on their own and in combination form were determined against S. aureus via macrodilution and microdilution methods. The synergistic antibacterial effect of silver nanoparticles and MBP-1 was investigated on infected wounds caused by S. aureus in a mouse model. RESULTS: The MIC and MBC of MBP-1 were found to be 0.6 and 0.7 mg/mL, respectively. MIC and MBC of silver nanoparticles were determined to be 6.25 and 12.5 mg/L, respectively. MIC and MBC of the silver nanoparticles and MBP-1 combination were found to be 3.125 mg/mL, 0.5 mg/L; and 6.25 mg/mL, 0.6 mg/L, respectively. The infected wound healed properly after the combined use of MBP-1 and silver nanoparticles. CONCLUSIONS: The synergistic effect was found on the healing of infected wounds caused by S. aureus by using an MBP-1 and silver nanoparticles combination in a mouse model.

Synthesis, characterization and immunological properties of Escherichia coli 0157:H7 lipopolysaccharide- diphtheria toxoid conjugate vaccine.

BACKGROUND AND OBJECTIVE: Escherichia coli O157:H7, an emerging pathogen, causes severe enteritis and the extraintestinal complication of hemolytic-uremic syndrome. The goal of this study was to evaluate the conjugate of E. coli O157: H7 lipopolysaccharide (LPS) with diphtheria toxoid (DT) as a candidate vaccine in mice model. MATERIAL AND METHODS: LPS from E. coli O157:H7 was extracted by hot phenol method and then detoxified. Purified LPS was coupled to DT with adipic acid dihydrazide (ADH) as a spacer and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as a linker. The coupling molar ratio of LPS to DT was 3:1. Clinical evaluation of E. coli O157:H7 LPS-DT conjugate was also performed. RESULTS: The conjugate was devoid of endotoxin activity and indicated 0.125 U/ml of D-LPS. Mice immunization with D-LPS DT conjugate elicited fourfold higher IgG antibody in comparison to D-LPS. Also, in vivo protection of mice with conjugate provided high protection against the LD50 of E. coli O157:H7, which indicated a good correlation with the IgG titer. CONCLUSION: Our results showed that the suggested vaccine composed of E. coli O157:H7 LPS and DT had a significant potential to protect against E. coli infections.

Pseudomonas aeruginosa PAO-1 Lipopolysaccharide-Diphtheria Toxoid Conjugate Vaccine: Preparation, Characterization and Immunogenicity.

BACKGROUND: Treatment of Pseudomonas aeruginosa PAO-1 infections through immunological means has been proved to be efficient and protective. OBJECTIVES: The purpose of this study was to produce a conjugate vaccine composed of detoxified lipopolysaccharide (D-LPS) P. aeruginosa and diphtheria toxoid (DT). MATERIALS AND METHODS: Firstly, LPS was purified and characterized from P. aeruginosa PAO1 and then detoxified. D-LPS was covalently coupled to DT as a carrier protein via amidation method with adipic acid dihydrazide (ADH) as a spacer molecule and 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDAC) as a linker. The molar ratio of LPS to DT in the prepared conjugate was 3:1. The immunogenicity of D-LPS-DT conjugate vaccine in mice model was evaluated as well. RESULTS: The conjugate was devoid of endotoxin activity and 0.125 U/mL of D-LPS was acceptable for immunization. D-LPS-DT conjugate was nonpyrogenic for rabbits and nontoxic for mice. Mice immunization with D-LPS-DT conjugate vaccine elicited the fourfold higher IgG antibody compared to D-LPS. Anti-LPS IgG antibody was predominantly IgG1 subclass and then IgG3, IgG2a and IgG2b, respectively. CONCLUSIONS: Vaccine based on the conjugation of P. aeruginosa PAO-1 LPS with DT increased anti-LPS antibodies and had a significant potential to protect against Pseudomonas infections.

Bactericidal Effect of Silver Nanoparticles on Intramacrophage Brucella abortus 544.

BACKGROUND: Brucellosis is an infectious disease that is caused by Brucella spp. As Brucella spp. are intramacrophage pathogens, the treatment of this infection is very difficult. On the other hand, due to the side effects of the brucellosis treatment regime, it is necessary to find new antimicrobial agents against it. OBJECTIVES: The aim of this study was to investigate the antimicrobial effect of silver nanoparticles against Brucella abortus 544 in the intramacrophage condition. MATERIALS AND METHODS: The antimicrobial effect of silver nanoparticles was determined by an agar well diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of silver nanoparticles against B. abortus 544 were determined by a broth macrodilution method. The effect of time on the antimicrobial activity of silver nanoparticles was analyzed. The effect of silver nanoparticles on the intramacrophage survival of B. abortus 544 was studied on mice peritoneal macrophages. RESULTS: The well diffusion agar study showed that silver nanoparticles have an antimicrobial effect on B. abortus 544. The MIC and MBC of silver nanoparticles against B. abortus 544 were; 6 ppm and 8 ppm, respectively. The silver nanoparticles showed antibacterial effects within 40 minutes. The results of the macrophage culture indicated that silver nanoparticles have antibacterial activity against intramacrophage B. abortus 544, and the highest efficiency was observed at a concentration of 8-10 ppm of silver nanoparticles. CONCLUSIONS: The results showed that silver nanoparticles have an antimicrobial effect against intramacrophage B. abortus 544.

Prevalence and antimicrobial resistance pattern of methicillin resistant Staphylococcus aureus (MRSA) strains isolated from clinical specimens in Ardabil, Iran.

BACKGROUND AND OBJECTIVE: Reports on MRSA strains are increasing worldwide. The aim of this study was to find the prevalence of MRSA strains isolated from clinical specimens and to evaluate their resistance profile. Additionally we compared the phenotypic and genotypic methods for detection of methicillin resistance. MATERIALS AND METHODS: In this cross-sectional study, a total of 41 isolates of S. aureus were collected from clinical specimens at two teaching hospitals in Ardabil, Iran. All isolates were identified at the species level by standard biochemical tests. The methicillin resistance were evaluated using three methods: PCR for mecA gene, agar dilution for determination of oxacillin MIC and disk diffusion test to detect methicillin, oxacillin and cefoxitin resistance. Antimicrobial resistance patterns were determined by disk diffusion method. RESULTS: The results identified 19 (46.3%) out of 41 isolates as MRSA. Most of the MRSA strains (68.4%) were isolated from patients hospitalized in ICU. All isolates were susceptible to vancomycin, mupirocin and linezolid. Among other antibiotics co-trimoxazole was more active against MRSA isolates. Using PCR as reference method all the phenotypic tests showed 100% specificity. The sensitivity for MIC test and cefoxitin was 100% and for methicillin and oxacillin disks was 77.7% and 89.5%, respectively. CONCLUSION: The prevalence of MRSA strains in our hospitals especially in ICU ward was high and disk diffusion testing using cefoxitin or oxacillin MIC test as an alternative to PCR for detection of MRSA is recommended.

Immunogenicity comparison of conjugate vaccines composed of alginate and lipopolysaccharide of Pseudomonas aeruginosa bound to diphtheria toxoid.

BACKGROUND AND OBJECTIVES: Treatment of Pseudomonas aeruginosa infections is greatly hampered by innate and acquired antibiotic resistance. The goal of this study was to compure the immunogenicity of conjugates of P. aeruginosa depolymerized alginate-diphtheria toxoid (D-ALGDT) and P. aeruginosa detoxified lipopolysaccharidediphtheria toxoid (D-LPSDT) in mouse model. MATERIALS AND METHODS: Alginate and LPS were purified from P. aeruginosa strain PAO1. The resulting depolymerized alginate (D-ALG) and detoxified LPS (D-LPS) were covalently coupled to diphtheria toxoid (DT) as a carrier protein with adipic acid dihydrazide (ADH) as a spacer molecule and carbodiimide as a linker. Sterility, safety and pyrogenicity tests were performed. 30 mice in two groups were immunized intraperitoneally on days 0, 14 and 28 with 10 µg of D-ALGDT and D-LPSDT. Conjugates specific antibody levels were also determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: The conjugates were non-toxic and non-pyrogenic. Conjugates of D-ALGDT and D-LPSDT were shown to be safe and to elicit total IgG, IgM, IgA, IgG1, IgG2a, IgG2b and IgG3 antibodies in mice. ELISA results indicated that antibodies titer of D-ALGDT was more than D-LPSDT. CONCLUSION: Immunization with D-ALGDT showed significant increase in all types of antibodies titers in versus D-LPSDT, suggesting D-ALGDT as a vaccine candidate against P. aeruginosa infections.

Prevalence of enterotoxigenic Staphylococcus aureus in organic milk and cheese in Tabriz, Iran.

BACKGROUND AND OBJECTIVES: Staphylococcal food poisoning is a gastrointestinal disease, which is caused by consumption of contaminated food with enterotoxins produced by Staphylococcus aureus (SEs). Milk and its products are known sources of food borne diseases. This study was carried out to evaluate the prevalence of enterotoxigenic S. aureus strains in organic milk and cheese in Tabriz - Iran. MATERIALS AND METHODS: A total of 200 samples (100 milk samples and 100 cheese samples) were collected from farms and milk collection points in Tabriz - Iran. The samples were cultured and identified by standard bacteriological methods, then PCR was performed to detect sea gene. RESULTS AND CONCLUSION: Staphylococcus aureus was found in 27% of all samples (milk and cheese). Results of PCR showed that 12.96% of S. aureus isolates possessed sea gene. It suggested the potential public health threat of S. aureus resulting from contamination of dairy products. So, efforts are required to improve safety standards for preventing staphylococcal food poisoning.

Induction of protective immunity against brucellosis in mice by vaccination with a combination of naloxone, alum, and heat-killed Brucella melitensis 16 M.

BACKGROUND/PURPOSE: A T-helper cell type 1-specific response leads to the elimination of intracellular infection with Brucella. Studies have shown that naloxone (NLX) can promote a cellular immune response in this respect. The current study was carried out to evaluate the induction of protective immunity in mice against brucellosis by vaccination with a combination of NLX, alum, and heat-killed Brucella melitensis 16 M (HKB). METHODS: Mice were categorized into five groups and received intraperitoneal vaccination on Days 0 and 7. Then serum levels of interferon (IFN)-γ and interleukin (IL)-4, the bacterial load, and the survival rate were measured 2 weeks after the last vaccination. RESULTS: The serum levels of IFN-γ, IL-4, and immunoglobulin G in the NLX + alum + HKB group were shown to be significantly increased (p < 0.05). Furthermore, the lowest bacterial load was observed in this group. The survival rate in groups vaccinated with combinations containing adjuvants was 100%. CONCLUSION: The combination of NLX and alum enhanced the immunogenicity of HKB, which can be used in the vaccination of animals and humans at risk of the disease.