Journal of Medical Microbiology and Infectious Diseases
Volume:11 Issue: 3, Summer 2023

Developing potent therapeutic vaccines against human papillomaviruses (HPVs) is crucial for the effective management of various HPV-associated cancers. DNA-based vaccines are attractive due to their safety, stability, and capacity to elicit a targeted immune response against specific antigens. Heat shock proteins (HSPs) can enhance the efficacy of DNA vaccines when used as adjuvants. In this study, we created a recombinant DNA molecule by fusing the HPV16 e7 gene with either the hspB1 or hsp27 gene and assessed its expression in a eukaryotic cell line.

Initially, we constructed a recombinant eukaryotic expression vector by inserting the hsp27-e7 fusion gene into the pcDNA3.1 (-) vector. The concentration and purity of the sample were evaluated using NanoDrop spectrophotometry. We cultured human embryonic kidney 293T (HEK-293T) cells in RPMI 1640 medium and transfected them with the pcDNA3.1-hsp27-e7 construct using Lipofectamine 2000 transfection reagent. After 48 hours, we assessed the expression of the Hsp27-E7 fusion protein by western blotting using an anti-E7 monoclonal antibody.

We successfully subcloned the hsp27-e7 fusion gene into the pcDNA3.1 (-) vector, and enzymatic digestion confirmed a distinct ~975 bp band on an agarose gel. The concentration and purity of the recombinant DNA vector in a 10 mL culture were measured to be 210 ng/µL and 1.86, respectively. Furthermore, the expression of the Hsp27-E7 fusion protein in HEK-293T cells was confirmed by Western blot analysis, which detected a distinct band of approximately 38 kDa.

Our in vitro findings demonstrate successful expression of the DNA construct encoding the hsp27-e7 gene, which can be utilized as a DNA vaccine for future in vivo investigations.

Hepatitis A virus (HAV) is a causative agent of acute hepatitis in humans, infecting more than one million individuals every year, including both symptomatic and asymptomatic infections. The currently available preventive vaccines for HAV are based on either wild-type or live-attenuated virus strains, which can contribute to the costliness of the vaccination process. Therefore, it may be worthwhile to explore the potential of subunit vaccines that utilize immunogenic viral products.

This study presents the results of a novel recombinant protein production study that employed the native structures of HAV-VP1 and HBs-Ag. The fusion protein underwent comprehensive characterization to evaluate its potential applications in diagnostics and immunization. The truncated recombinant protein, HAV-VP1 (position 99-259 aa) -HBs-Ag, was successfully expressed in the Escherichia coli BL21-DE3 system.

The recombinant protein, with a molecular weight of 46 kDa, was evaluated using SDS-PAGE gel electrophoresis and confirmed by western blotting. The fusion protein was successfully detected in serum samples positive for HBV or HAV using anti-HBs and anti-VP1 antibodies. Additionally, it elicited a potent humoral response in BALB/c mice.

The novel recombinant protein described in this study has the potential to serve as a bivalent vaccine against HAV and HBV infections. The next step involves evaluating the immunogenicity and safety profile of the protein.

Pseudomonas aeruginosa, a nosocomial pathogen, causes respiratory infections, particularly in individuals with cystic fibrosis (CF); it poses a significant challenge due to escalating antibiotic resistance. Phage therapy is emerging as a potential alternative approach to treating antibiotic-resistant bacteria. This study aimed to isolate and identify a highly efficacious bacteriophage targeting P. aeruginosa.

Sewage samples from Mofid Children's Hospital were collected and titrated using a double-layer plaque assay. After plaque detection, the phage was isolated, and then the host range, adsorption rate, and stability were evaluated through spot tests and double-layer plaque assays. Phage morphology was determined using transmission electron microscopy (TEM).

Of the three sewage samples collected, one contained phage. We isolated a lytic bacteriophage that exhibited clear plaque formation and induced lysis in planktonic P. aeruginosa. TEM analysis revealed that the phage belonged to the Myoviridae family. The phage had a broad host range and demonstrated optimal stability at 37 °C and pH 7.

The isolated phage can potentially be used for treating P. aeruginosa lung infections, offering an alternative approach to address drug-resistant isolates.

The hospital environment can significantly contribute to the spreading of bacterial isolates that pose a risk to public health. In this study, we analyzed bacteria found on hospital fomites and the hands of healthcare workers to determine the presence of resistant enzymes such as ESBLs and AmpC.

We studied 100 samples collected from hospital fomites - including the hands of healthcare workers - for bacterial growth, which were subsequently identified using standard procedures. Standard disk methods were used to screen Gram-negative bacteria (GNB) for ESBL and AmpC production, including presumptive and confirmatory testing.

46 (46.0%) Gram-negative bacteria were isolated from all sampling sites, including a preponderance of Pseudomonas aeruginosa and Escherichia coli. Of the 46 GNBs, 31 (67.4%) and 27 (58.7%) were resistant to ceftazidime and ceftriaxone, respectively. The double disk synergy test (DDST) showed ESBL in 34 (73.1%) of the isolates, with the highest prevalence in E. coli (32.3%) and P. aeruginosa (26.5%). These isolates were primarily associated with patients’ bedding (32.4%), tablets (26.5%), and sinks (20.6%), although there was no statistical difference (P=0.998). Presumptive AmpC production was 100% in isolates of K. pneumoniae, C. diversus, Shigella spp., and S. marcescens but variable in other isolates. The combined disk test (CDT) showed that 29 (63.0%) isolates were AmpC-producing GNB, with the highest prevalence in E. coli (34.5%).

The isolation of bacteria with these types of resistance from the surfaces of hospital fomites may negatively impact the quality of healthcare delivery.

Biofilms are often found in communities of microorganisms in chronic and persistent infections, exhibiting high resistance against antimicrobial agents. Biofilm serves as a barrier, impeding the penetration of drugs and constraining their effectiveness. Multiple methods, such as the Tissue Culture Plate method, Congo Red Agar method, Tube method, bioluminescent assay, and fluorescent microscopic examination, can be used to evaluate biofilm production.

The study included a total of 300 clinical isolates representing a range of bacterial species, including Acinetobacter baumannii (n=9), Coagulase Negative Staphylococcus (n=7), Enterobacter aerogenes (n=7), Enterococcus faecalis (n=15), Escherichia coli (n=137), Klebsiella pneumoniae (n=23), Proteus mirabilis (n=4), Pseudomonas aeruginosa (n=16), Salmonella typhi (n=11), and Staphylococcus aureus (n=68). Associations among isolates capable and incapable of biofilm formation and their multidrug resistance phenotypes were evaluated.

Among the 300 clinical isolates tested, 289 isolates (96.3%) exhibited biofilm formation. The most prevalent biofilm-forming organisms were A. baumannii (n=9), Citrobacter koseri (n=1), Coagulase Negative Staphylococcus (CONS) (n=7), E. aerogenes (n=7), E. faecalis (n=15), E. coli (n=137), Klebsiella oxytoca (n=1), K. pneumoniae (n=23), P. mirabilis (n=4), P. aeruginosa (n=16), S. typhi (n=11), S. aureus (n=68), and Streptococcus pneumoniae (n=1). The biofilm-forming isolates demonstrated increased resistance compared to isolates that did not form biofilms.

Antimicrobial resistance represents a critical characteristic of infections involving biofilms. The study identified biofilm production in 92.7% of the isolates tested via TCP and in 72.3% of the isolates using the CRA. Furthermore, it was observed that pathogens with multidrug resistance (MDR) exhibited a higher biofilm production tendency than non-producing pathogens.

The widespread use of antibiotics has contributed to the dissemination of multidrug-resistant pathogens. This study aimed to assess the prevalence of Escherichia coli strains associated with urinary tract infections, characterized by diverse drug-resistance phenotypes. Additionally, the antibacterial properties of gold nanoparticles were examined against each phenotype to determine their effectiveness.

This cross-sectional study was conducted on 170 E. coli strains isolated from 250 urine samples collected from symptomatic and asymptomatic patients with urinary tract infections (UTIs) between August 2022 and July 2023. The antibiotic susceptibility profiles across various classes of antibiotics were determined using the Kirby-Bauer method. At the same time, the minimum inhibitory concentrations of gold nanoparticles were assessed through the microdilution broth test.

Among E. coli isolates, 91 (53.53%), 45 (26.47%), and 17 (10%) isolates were identified as multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR), respectively. The MIC of gold nanoparticles that inhibited the growth of 90% of PDR isolates (MIC90=200 ppm) was two times higher than the MIC90 against XDR isolates (MIC90=100 ppm) and four times higher than the MIC90 against MDR isolates (MIC90=50 ppm). There was also a significant difference between the MIC90 and the MIC of gold nanoparticles that inhibited the growth of 50% of PDR and XDR bacteria (P<0.05).

The emergence of MDR, XDR, and PDR uropathogenic E. coli isolates represents a significant societal health concern. Considering the favorable in vitro antimicrobial potential of gold nanoparticles against uropathogenic E. coli isolates, it is recommended to further analyze their applicability as antibiotic alternatives by conducting in vivo studies.

  This study assesses immature granulocyte count as an early predictor of blood culture positivity in pediatric cardiac patients. Early diagnosis of sepsis is crucial but challenging. Blood culture is the gold standard; however, obtaining results takes 48-72 h. The study compares these indicators with other predictive markers of sepsis.

This retrospective study analyzed data from 200 pediatric patients to assess the use of immature granulocyte count as an early predictor of blood culture positivity in pediatric cardiac surgery patients with sepsis. The patients were divided into two groups based on blood culture

positive and negative. A complete blood count was conducted for both groups, including immature granulocyte count and demographic information. The data were collected for two periods: 24-48 h before the blood culture and 24 hours after. The study aimed to evaluate the diagnostic utility of immature granulocyte count and compare it with other established predictive markers of sepsis. The blood counts were performed using SYSMAX XN1000.

The study observed higher immature granulocyte counts in patients with culture-positive results during period 2 diagnosis (P<0.001). No significant differences were found in other lab parameters between the two groups. The receiver operating characteristic (ROC) curve analysis showed that an immature granulocyte count ≥ 90 was helpful in predicting blood culture positivity in pediatric cardiac surgery patients with sepsis.

Our study reveals that the Absolute Immature Granulocyte Count and Immature Granulocyte percentage (IG%) significantly increase within 24-48 hours of positive blood cultures compared to negative cases.

Bacterial vaginosis (BV) is the most common vaginitis in childbearing women. Despite the availability of various treatments, recurrence rates are high. This study investigated the effects and side effects of vitamin C vaginal tablets in patients with Gardnerella vaginalis infection based on Amsel criteria and the culture.

A double-blind, randomized clinical trial was conducted on 48 non-pregnant women aged 15-40 years referred to Alawi Hospital in Ardabil Province, Iran. After the diagnosis of G. vaginalis infection based on Amsel criteria and culture methods, the patients were randomly assigned to receive either intravaginal 250 mg vitamin C (intervention group, n=24) or 250 mg metronidazole tablets (control group, n=24) for eight nights. The patients were evaluated 10 ± 2 and 30 ± 2 days before and after the treatment.

Culture and Amsel criteria showed significant improvement in both groups during the first and fourth weeks of treatment. However, the intervention group that received vitamin C showed a more substantial improvement (P<0.002, P<0.001). Intravaginal vitamin tablets were more effective than metronidazole tablets in treating G. vaginalis infection. Furthermore, vitamin C tablets improved the abnormal growth of vaginal microflora and reduced the abnormally high pH of the vagina. This treatment effectively prevented the recurrence of G. vaginalis infection for one month.

Vitamin C vaginal tablets showed to be a promising alternative treatment for G. vaginalis infection, but further research is needed to confirm these findings and address potential limitations.