Masoud Yousefi

CFP10: mFcγ2 as a novel tuberculosis vaccine candidate increases immune response in mouse

Objective(s): Despite treatment with antibiotics and vaccination with BCG, tuberculosis (TB) is still considered as one of the most important public health problems in the world. Therefore, designing and producing a more effective vaccine against TB seems urgently. In this study, immunogenicity of a fusion protein which consisting or comprising CFP-10 from Mycobacterium tuberculosis and the Fc-domain of mouse IgG2a was evaluated as a novel subunit vaccine candidate against TB. Materials and Methods: The genetic constructs were cloned in pPICZαA expression vector and recombinant vectors (pPICZαA-CFP-10: Fcγ2a and pPICZαA-CFP-10:His) were transformed into Pichia pastoris. To evaluate the expression of recombinant proteins, SDS-PAGE and immunoblotting were used. The immunogenicity of recombinant proteins, with and without BCG were assessed in BALB/c mice and specific cytokines against recombinant proteins (IFN-γ, IL-12, IL-4, IL-17 and TGF-β) were evaluated. Results: The levels of IFN-γ and IL-12 in mice that received recombinant proteins was higher than the control groups (BCG and PBS). Thus, both recombinant proteins (CFP-10:Fcγ2a and CFP-10:His) could excite good response in Th1-cells. The Fc-tagged protein had a stronger Th1 response with low levels of IL-4, as compared to CFP-10:His. However, the highest level of Th1 response was observed in groups that were vaccinated with BCG (prime) and then received recombinant protein CFP-10: Fcγ2a (booster). Conclusion: The results demonstrated that binding mice Fc-domain to CFP-10 protein can increase the immunogenicity of the subunit vaccine. Further studies, might be able to design and produce a new generation of subunit vaccines based on the Fc-fused immunogen.

High prevalence of sequence type 131 isolates producing CTX-M-15 among extended-spectrum β-lactamase-producing Escherichia coli strains in northeast Iran

OBJECTIVES The recent expansion of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is a worldwide problem. The purpose of this study was to investigate the molecular characteristics of ESBL-producing E. coli strains in Mashhad, located in the northeast of Iran. METHODS A total of 455 clinical E. coli isolates were collected at three hospitals in Mashhad between April-September 2015. Antimicrobial susceptibility was determined by the Kirby-Bauer disk diffusion test. The combination disk test was performed for phenotypic detection of ESBLs. PCR was used to screen isolates for ESBL typing. Phylogenetic groups and sequence type 131 (ST131) were determined by multiplex PCR. RESULTS The prevalence of ESBL-producing E. coli among the collected strains was 51.6% (235/455). Among the 235 ESBL-producing strains, 222 (94.5%) tested positive for CTX-M type, whilst 115 (48.9%), 92 (39.1%) and 21 (8.9%) were positive for TEM, OXA and SHV, respectively. Moreover, CTX-M-15 (94.1%; 209/222) was the most common ESBL among E. coli. Based on multiplex PCR, phylogenetic group B2 was predominant (169/235; 71.9%), followed by D (32/235; 13.6%), A (21/235; 8.9%) and B1 (13/235; 5.5%). ST131 was the predominant clonal group among the phylogenetic group B2 isolates (151/169; 89.3%). CONCLUSION The results revealed that an urgent investigation of the source and transmission pathways of the CTX-M-15-B2-ST131 E. coli clone is needed to mitigate this emergent public-health problem.

Synthesis of the erythromycin-conjugated nanodendrimer and its antibacterial activity

ABSTRACT The development and spread of bacterial resistance to antimicrobial drugs necessitates the need to search for novel and effective antimicrobial agents. In the last few decades, innovative nanomaterials are attracting increasing attention and, among them, dendrimers have shown wide application in the various fields. In the current study, the two generations of an anionic linear‐ spherical nanodendrimer G1 and G2 were synthetized and compound G2 of nanodendrimer conjugated with erythromycin. The structures of the nanodendrimers were characterized by FTIR spectroscopy, zetasizer, and scanning electron microscopy (SEM). The antibacterial activity of the erythromycin‐conjugated nanodendrimer and erythromycin alone were evaluated by the microdilution method against Staphylococcus aureus, S. epidermidis, S. saprophyticus, and Pseudomonas aeruginosa. The size of first and second generation of nanodendrimer, and the erythromycin‐conjugated nanodendrimer was 75, 95, and 65.6 nm, respectively. The drug loading percentage of the nanodendrimer conjugates was obtained to be in 35.2%. In our study, the erythromycin‐conjugated nanodendrimer showed significantly more bacteriostatic and bactericidal activities against all four studied bacteria than erythromycin alone. Our studys results highlight that the erythromycin‐conjugated nanodendrimer is a highly effective agent against Gram positive and negative bacteria. The antibacterial properties of erythromycin combined with the targeting potential of the nanodendrimer can lead to sustained intracellular delivery of therapeutic agent. Graphical abstract Figure. No Caption available.

Clinical outcomes of the simultaneous bilateral percutaneous nephrolithotomy (PCNL) in patients with kidney stones: A prospective cohort study

Background Urinary tract stones is one of the most frequent medical emergencies which leads to life-threatening complications, namely obstructive uropathy as well as renal failure in some situations. Previously, bilateral stones were treated with either open surgery or percutaneous nephrolithotomy (PCNL). However, these treatment options were associated with lengthy operation time, need for more anesthesia, further bleeding, and long hospitalization. Therefore, much effort has been made to treat both sides simultaneously. Objective The aim of this study was an attempt to prospectively review cases undergoing simultaneous bilateral PCNL in terms of the therapy outcomes, complications, and consequences. Methods In this prospective cohort study, 39 adult patients with bilateral renal stones were randomly recruited at Imam Reza hospital in Mashhad, Iran between January 2016 and January 2017. Adult patients with bilateral renal stones were included in this study. Exclusion criteria were as follows: Patients with severe heart or lung disease, patients with coagulation disorders, pregnant women, and cases with any contraindications for general anesthesia. After insertion of bilateral ureteral catheters, all patients underwent simultaneous bilateral PCNL in prone position. Transureteral lithotripsy was performed for patients with ureteral stones. The surgery was initially carried out on the symptomatic side and then iterated on the remaining kidney. Major complications including bleeding, fever, pain, urine leakage, and residual stones were recorded. SPSS software was used for data analysis. Data were expressed as percentage and mean ± SD. P value less than 0.05 was considered significant. Results A total of 39 patients (27 males with mean age of 37.6 years and 12 females with mean age of 45.7 years) were studied. As many as 15 (38%) patients received a unilateral nephrostomy. Three underwent totally tubeless surgery. Bleeding (41.0%) was the most common complication, followed by residual stones (20.5%) and fever (20.5%), urine leakage (15.3%), pain (12.8%), blood transfusion (2.5%) and colon perforation (2.5%). Conclusions It was concluded that simultaneous bilateral PCNL was not associated with higher morbidity than the unilateral method.

Identification of tigecycline- and vancomycin-resistant Staphylococcus aureus strains among patients with urinary tract infection in Iran

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causes of hospital- and community-acquired infections worldwide. Although S. aureus rarely accounts for urinary tract infections (UTI), untreated UTI can lead to several complications. For decades vancomycin has been used for the treatment of MRSA infections. This study was performed to assess the in vitro activity of vancomycin, tigecycline, linezolid and quinupristin/dalfopristin against MRSA isolates from UTI patients. Thirty MRSA strains from 54 S. aureus isolates were isolated from patients with UTI. The antimicrobial susceptibility patterns of the strains were determined by the Kirby-Bauer disk diffusion and broth microdilution methods. PCR assays were used to detect the vanA gene. The MRSA isolates resistant to vancomycin were confirmed using the broth microdilution method. The results revealed that the MRSA isolates were 100% susceptible to linezolid and quinupristin/dalfopristin but 93.3% susceptible to vancomycin and tigecycline respectively. The broth microdilution method confirmed two MRSA strains (6.6%) to be resistant to vancomycin and tigecycline. The study identified vancomycin resistance among the MRSA isolates from UTI patients. This vancomycin resistance in MRSA isolates poses a challenge in managing S. aureus infections. Our studys results highlight the need to correctly identify patients in whom last-resort therapy such as linezolid and quinupristin/dalfopristin should be administered.

Frequency of efflux pump genes mediating ciprofloxacin and antiseptic resistance in methicillin-resistant Staphylococcus aureus isolates

Efflux pumps are well known as a key role to fluoroquinolone resistance in methicillin-resistant Staphylococcus aureus (MRSA). In this study, among 60 clinical MRSA isolates, 42 isolates (70%) were resistant to ciprofloxacin. MRSA were isolated to detect efflux genes including norA, norB, norC, mepA, sepA, mdeA, qacA/B and smr. Isolates subjected to PCR detection and DNA sequence analysis for these genes. PCR detection showed that 42 isolates (70%) contained at least one efflux pump gene. Among ciprofloxacin-resistant isolates, mdeA and qacA/B genes were found with the highest (61.7%) and lowest (3.3%) frequency, respectively. We also observed that the highest minimum inhibitory concentrations of ciprofloxacin in the presence of mdeA+mepA+norA-C+sepA+smr combination. This type of combination may have the greatest impact on resistance to ciprofloxacin. Finally, compared to previous studies, our study demonstrates that prevalence of ciprofloxacin resistance has been increasing among MRSA clinical isolates.

Identification of nontuberculous mycobacteria by high-performance liquid chromatography from patients in tehran.

Background/Objectives: The genus Mycobacterium contains over 140 species comprises pathogenic and nonpathogenic strains. Nontuberculous mycobacteria (NTM) causing clinical disease have become increasingly common and more diverse. Widespread features of NTM infection can make the diagnosis difficult. Precise species-level detection can aid in distinguishing environmental contamination from actual infection and, furthermore, can assist in making a choice of antimicrobial therapy. Materials and methods: Mycolic acids extracted from saponified mycobacterial cells were examined by high performance liquid chromatography (HPLC) in addition to phenotypic tests for the identification of 20 clinical isolates of mycobacteria at Masoud Laboratory during 2014–2015. Results: Mycobacterium abscessus (8 isolates), Mycobacterium tuberculosis (6 isolates), Mycobacterium intracellulare (3 isolates) and Mycobacterium fortuitum (3 isolates) were identified in these isolates. The phenotypic tests also confirmed the identity of the clinical isolates. Conclusion: Our results showed that HPLC is a more reliable, rapid, simple, easy-to-perform, cost-effective, and specific identification method compared with other identification procedures like phenotypic tests.