Jundishapur Journal of Microbiology
Volume:16 Issue: 12, Dec 2023

“Salmonella species can cause various infections in humans and animals. The presence of certain genes determines the virulence of a Salmonella serotype”.

The current research endeavor was undertaken to assess the virulence characteristics and genotypic traits of Salmonella serotypes extracted from various sources within the geographical boundaries of Iran.

Salmonella isolates, previously retrieved and preserved in the veterinary microbiology laboratory, underwent serotyping and polymerase chain reaction (PCR) identification of nine virulence-associated genes. Genotyping was carried out using random amplified polymorphic DNA-PCR (RAPD-PCR).

All Salmonella isolates showed the presence of invA, sdiA, hilA, and iroB virulence genes. There were a total of 17 different virulence gene patterns among Salmonella serotypes. The presence of fliC and sefA genes and their related patterns were significant among S. typhimurium and S. enteritidis serotypes, respectively (P < 0.05). In the RAPD-PCR fingerprinting, 11 distinct clusters were obtained, and 16 isolates (26.66%) were classified as untypeable strains. There was a significant association between RAPD genotypes and Salmonella serotypes (P < 0.05), while the association between these RAPD patterns and the source of the isolates was not significant (P > 0.05).

According to the results, Salmonella serotypes from non-human sources carry significant virulence determinants and show similar genotypic patterns with human isolates. These findings provide valuable insights into the virulence properties and genetic diversity of Salmonella serotypes in Iran, which could inform the development of effective control and prevention strategies for salmonellosis in the region.

Since the emergence of COVID-19 and the pandemic declaration, this disease has become the top priority for global healthcare systems. The standard diagnostic tool for COVID-19 involves conducting imaging studies alongside real-time polymerase chain reaction (RT-PCR) tests on nasopharyngeal or oropharyngeal samples.

Given the potential extrapulmonary involvement of COVID-19, our objective was to evaluate the diagnostic effectiveness of double pharyngeal sampling, as well as the use of saliva and anal swabs.

This cross-sectional study involved 102 pediatric patients suspected of having COVID-19. After the routine nasopharyngeal sampling, additional samples were collected from the nasopharynx, saliva, and anal canal. These samples were subjected to RT-PCR testing using Taq Man’s probe-based technology. The statistical analysis included sensitivity, specificity, positive and negative predictive values, and Kappa agreement measurement.

In this study, with a COVID-19 prevalence of 92.2%, we compared the diagnostic efficacy of different methods. When having at least one positive sample was considered the gold standard, double nasopharyngeal sampling exhibited the highest sensitivity, followed by RT-PCR of saliva and anal swabs (94.9%, 92.9%, and 91.9%, respectively). When double sampling was considered the gold standard for diagnosis, saliva RT-PCR showed the highest sensitivity and negative predictive value (93.6% and 40.0%, respectively). However, there was no significant difference in the specificity and positive predictive value between anal swabs and saliva RT-PCR. However, when anal swabs and saliva were compared with only one nasopharyngeal sample, anal swabs performed slightly better than saliva.

While the combination of double sampling from the nasopharynx and oropharynx, along with anal swabs and saliva, proved effective for diagnosing COVID-19, routine use of these methods may not be cost-effective. However, during periods of epidemic control, when comprehensive case identification is crucial, these methods may warrant consideration for more extensive investigations.

Vibrio vulnificus can cause serious infections in human beings associated with the consumption of rawoysters or cuts exposed to seawater. The traditional method for culturing V. vulnificus is time-consuming and has a high failure rate.

This study aims to detect V. vulnificus using an AMCA-modified specific DNA aptamer.

Common pathogenic microorganisms present in the seawater of the Fujian Sea area were collected, cultured, and identified. The samples were found to contain mainly V. vulnificus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, V. alginolyticus, V. parahaemolyticus, and V. cholerae. AMCA was conjugated with 5’ ends of the aptamer using N-hydroxysuccinimide ester (NHS ester) to target V. vulnificus and produce a fluorescent signal upon binding. The aptamer was screened and optimized for rapid detection of V. vulnificus.We collected the 50 bacterial strains isolated from clinical secretion samples and used a fluorescence microscope to determine whether the sample contained V. vulnificus or not. We compared these results with those obtained from VITEK MS (considered the gold standard) to test the sensitivity and specificity of the AMCA-modified aptamer using IBM SPSS Statistics 22.

In this experiment, the sensitivity and specificity of the modified aptamer for detecting V. vulnificus were determined to be 100% [95% CI (0.39, 1)] and 93.4% [95% CI (0.81, 0.98)], respectively. The positive predictive value was 57% [95% CI (0.20, 0.88)], and the negative predictive value was 100% [95% CI (0.89, 1)]. These findings indicate that V. vulnificus specimens can be rapidly detected via fluorescence reaction within 30 minutes.

Our results suggest that this modified DNA aptamer has the potential to be used for diagnosing V. vulnificus. Further research is needed to explore the application of aptamers in pathogen infections.

Carbapenem-resistant Klebsiella pneumoniae (Cr-KPN) poses a significant global public health challenge.

This study aimed to investigate the prevalence and expression levels of carbapenemase-encoding genes in Cr-KPN isolated from patients admitted to teaching hospitals in Shiraz, Iran.

A total of 671 distinct clinical samples were collected from two teaching hospitals in Shiraz. Initial identification and final confirmation of K. pneumoniae isolates were carried out using conventional biochemical tests and PCR assays, respectively. The detection of carbapenemase-producing K. pneumoniae, both phenotypically and genotypically, was performed through modified carbapenem inactivation methods (mCIM) and multiplex PCR assays. Real-time PCR was utilized to assess the expression levels of carbapenemase-encoding genes.

The overall frequency of K. pneumoniae strains was 14.9% (n = 100/671). mCIM indicated that 26% of K. pneumoniae isolates exhibited carbapenemase production. Furthermore, 24% and 17% of K. pneumoniae isolates demonstrated resistance to imipenem and meropenem, respectively. The blaIMI/IMP gene was detected in 91% of the isolates. Among imipenem-resistant isolates, 62.5% tested positive for the blaOXA-48 gene. Additionally, 29.4%, 76.5%, and 11.8% of meropenem-resistant isolates were positive for the blaKPC, blaOXA-48, and blaNDM genes, respectively. Real-time PCR analysis revealed increased expression levels of blaKPC (1.66-fold), blaOXA-48 (7.30-fold), blaNDM (4.22-fold), and blaIMI/NMC (2.39-fold) genes in resistant isolates when exposed to imipenem.

These findings underscore the significance of establishing active surveillance networks to monitor and track the dissemination of carbapenemase-producing K. pneumoniae, which presents a global public health threat.

Despite global control measures aimed at ending the COVID-19 pandemic, the disease continues to pose a threat to public health. In this study, we examined the serum levels of vitamins C, D, and E, as well as IgG and IgM antibodies in individuals who had previously been vaccinated against COVID-19 and subsequently experienced a relapse of the disease.

The objective of this study was to investigate the correlation between sufficient levels of vitamins E,D, and C, the severity of the disease, and the immunological response in vaccinated patients who have experienced a recurrence of COVID-19.

Given the potential role of vitamins C, D, and E in the management of COVID-19, we conducted a study to examine the serum levels of these vitamins in individuals who had previously been vaccinated against COVID-19 and experienced a disease relapse, characterized by symptoms, such as body pain, shortness of breath, cough, and fever. We compared two groups of hospitalized individuals with varying disease severity to healthy individuals. Additionally, we investigated IgG and IgM antibodies in these patients due to the significance of antibody levels in determining disease severity.

Our results revealed significant differences in the levels of vitamins C, D, and E between hospitalized individuals and healthy individuals. Furthermore, a notable disparity in serum IgM and IgG levels was observed based on the severity of the disease. However, no significant difference was detected in the average levels of anti-SARS-CoV-2 immunoglobulins among the different groups, whether they had received the AstraZeneca or Sinopharm vaccines.

Vitamins C, D, and E play supportive roles in the immune system, aiding the host’s immune response. These findings suggest that maintaining adequate levels of these vitamins may be beneficial in preventing SARS-CoV-2 reinfection and reducing disease severity, particularly in cases where vaccine efficacy is uncertain.

The incidence of invasive aspergillosis (IA) has significantly increased in recent decades. In patients with hematologic malignancies (HM), IA is associated with higher mortality rates.

This study aimed to assess the clinical features of IA in patients with HM.

In this retrospective study, we utilized the hospital information system (HIS) database to extract clinical and paraclinical characteristics of patients with variousHMswhoreceived a diagnosis of probable or proven IA during their hospitalization atImam Khomeini Hospital Complex in Tehran, Iran, between March 2018 and March 2022

Among350 patients withHMevaluated, 51 patients (14.6%) were identified as having IA, including 40 cases (78.4%) classified as probable and 11 (21.6%) as proven. Among these, 34 individuals (66.7%) were male. The most common symptoms included fever (n = 23, 62.7%), cough (n = 20, 39.2%), and fever that did not respond to antibiotic therapy (n = 16, 31.4%). The most prevalent malignancies wereAML(n = 28, 54.9%), ALL (n = 16, 31.4%), andlymphoma(n = 7, 13.7%). Out of the 51 patients withHMand IA, 48 (94.1%) had abnormal findings on chest CT scans, with the majority (n = 31, 72.1%) showing a nodule with a halo sign. Aspergillus flavus (n = 19/24, 79.2%) was the most commonly isolated species. Initially, patients received liposomal amphotericin B or caspofungin as empiric antifungal therapy, which was then switched to voriconazole once the diagnosis of IA was probable or proven. Eight patients (15.6%) did not survive.

Patients with HM presenting with fever and cough should undergo close monitoring for IA. A higher incidence of IA is observed in AML patients, and voriconazole could be considered as antifungal prophylaxis in HM patients. A. flavus is likely the most frequent cause of IA in Iranian patients with HM.

 
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes immune system dysregulation and a systemic cytokine storm. Under healthy conditions, T helper cells protect against intracellular pathogens, extracellular parasites, and extracellular bacteria.

For the novelty of our study, little is known regarding the balance of T cell subtypes and responses in two forms of COVID-19 in our country. We investigated whether there was a relationship between T cell subtype frequency and cytokines by COVID-19 severity.

Forty-six PCR-confirmed severe (n = 30) and moderate (n = 16) COVID-19 patients and 13 sex- and age-matched healthy control (HC) subjects were enrolled. Immunophenotyping of T cell subsets and related serum cytokines was performed using flow cytometry and ELISA, respectively.

There was a significantly lower frequency of CD8+Tbet+ (P < 0.01) T cells in the severe group compared to HC. Also, there was a significantly lower frequency of CD4+GATA3+ (P < 0.001) and CD8+Tbet+ (P < 0.001) T cells in the severe group compared to the moderate group. Moreover, receiver-operating characteristic (ROC) curve analysis revealed a considerable correlation between CTL (CD8+T-bet+) subtypes and the severity of the disease. Severe COVID-19 disease was associated with reduced interferon-gamma (IFN-γ) and interleukin (IL)-2 concentration and increased IL-5 and IL-6 concentration.

Reduced systemic levels of IL-2 can trigger decreased numbers of Th1 and Th2 cells, and in contrast to elevated IL-5 and IL-6, the numbers of Th2 cells did not increase in these cases.