Jundishapur Journal of Microbiology
Volume:17 Issue: 2, Feb 2024

 Persistent detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in individuals who have recovered from coronavirus disease 2019 (COVID-19) remains an unexplained phenomenon warranting further study. Recent research suggests that this RNA could be the result of transcription from an integrated SARS-CoV-2 genome.

 This study aimed to investigate the presence of the DNA form of the SARS-CoV-2 genome in oropharyngeal, nasopharyngeal, and peripheral blood mononuclear cell (PBMC) samples from COVID-19 patients with prolonged viral detection.

 We examined the presence of the reverse-transcribed viral genome in samples from eighty COVID-19 patients, including 40 outpatients (group 1), 40 hospitalized patients (group 2), and 40 healthy individuals (group 3), using a TaqMan® based real-time RT-PCR assay.

 The mean ages of groups 1, 2, and 3 were 36.1 ± 11.0, 61.6 ± 18.4, and 39.0 ± 8.7, respectively. The molecular tests did not detect viral DNA forms, which may be produced during the SARS-CoV-2 life cycle, in the examined samples.

 Although no evidence of integrated viral DNA was found in this study, further research is essential to confirm these findings and explore the underlying mechanisms of prolonged SARS-CoV-2 RNA presence in recovered COVID-19 patients.

 Staphylococcus aureus is a significant bacterial pathogen globally recognized as the primary cause of numerous uncomplicated skin infections and severe invasive infections. The emergence of methicillin-resistant S. aureus (MRSA) poses a serious threat, leading to severe infections in both hospitals and community settings.

 The aim of this study was to identify antibiotic resistance patterns and perform molecular classification of S. aureus strains isolated from both hospital and community settings in southern Iran.

 In this cross-sectional study conducted in Bandar Abbas between 2020 and 2021, a total of 156 clinical strains of S. aureus were collected. Antibiotic susceptibility was determined using the disk-diffusion agar method. The presence of the pvl gene, Sccmec types, and Agr group was identified through PCR analysis. Additionally, Multilocus sequence typing (MLST) was performed on selected isolates.

 The study identified 156 strains, with 79 obtained from inpatients and 77 from outpatients, sourced from clinical samples. Among these isolates, 70 (44.8%) were classified as MRSA. The highest resistance was noted against azithromycin (83%), while the lowest resistance was observed for linezolid (5%) and gentamicin (7%). The presence of the pvl gene was detected in isolates from both hospital and community sources. Significant differences were noted in the occurrence of agr I and agr III genes between hospital and community isolates. Sccmec III was more predominant than other SCCmec types. Furthermore, MLST analysis revealed the presence of five distinct novel sequence types (STs): ST8634, ST8640, ST8650, ST8651, and ST8652.

 The findings indicate that the potential spread of hospital-acquired S. aureus strains to the community and vice versa poses a significant public health risk. This underscores the urgent need for robust infection control strategies and the identification of potential environmental and hospital sources of resistant strains, particularly MRSA strains.

 Colorectal cancer (CRC) is a major global health concern, and the link with Fusobacterium nucleatum has received considerable attention.

 This study aimed to explore the prevalence of F. nucleatum and to assess the expression of the msh2, mlh1, and msh6 genes in CRC patients compared to a control group using real-time PCR.

 Forty CRC patients and twenty individuals from a control group participated in this study. Gastroenterologists collected biopsy specimens from which DNA and RNA were extracted using a specialized tissue extraction kit. Complementary DNA (cDNA) was then synthesized. Real-time PCR was employed to evaluate the expression levels of the msh2, mlh1, and msh6 genes and the presence of the F. nucleatum-specific 16srRNA gene to determine the relative prevalence of this bacterium in each group.

 Results indicated a higher prevalence of the F. nucleatum-specific 16srRNA gene in CRC patients than in the control group. Additionally, expression levels of the msh2, mlh1, and msh6 genes were significantly higher in the cancer group, suggesting their role in CRC pathogenesis. The distribution of F. nucleatum was particularly high in the sigmoid and rectum areas of the colon.

 This study underscores the significance of F. nucleatum in CRC and provides insights into its association with altered gene expression patterns. Understanding the prevalence of F. nucleatum and its impact on msh2, mlh1, and msh6 genes may aid in developing improved diagnostic and therapeutic strategies for CRC. Further research is necessary to elucidate these relationships more comprehensively.

Leishmania spp. protozoa cause leishmaniasis by infecting macrophages. Long non-coding RNAs (lncRNAs), such as H19, Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT), HOX Antisense Intergenic RNA (HOTAIR), and TNF and HNRNPL Related Immuno-regulatory lncRNA (THRIL), play a role in macrophage polarization and gene regulation. Additionally, leukocytes can synthesize and respond to melatonin, yet the regulatory role of melatonin in Leishmania major-infected macrophages is not well understood.

This study aimed to assess the impact of melatonin on the expression of lncRNAs like H19, MALAT, HOTAIR, and THRIL, as well as on nitric oxide synthase (NOS) activity in L. major-infected macrophages.

Leishmania major promastigotes and U937 cell lines were cultured. Macrophages were infected with the promastigotes and subsequently treated with melatonin at concentrations of 3, 10, 30, and 100 nM for durations of 4, 24, and 48 hours. The expression levels of the lncRNAs and NOS activity were measured using quantitative Polymerase Chain Reaction (q-PCR) and spectrophotometry, respectively.

Melatonin treatment (100 nM) significantly increased the expression of H19 compared to the control after 48 hours (P = 0.002). There was also a significant upregulation of MALAT and HOTAIR in macrophages treated with 3 nM melatonin compared to controls after 48 hours (P = 0.02 and P = 0.003, respectively). Additionally, THRIL expression significantly increased in the melatonin group (10 nM) compared to the control after 4 hours of treatment (P = 0.003). An increase in NOS activity was observed in the melatonin group (100 nM) compared to the control at 4 hours, 24 hours, and 48 hours (P = 0.034, P = 0.011, and P = 0.014, respectively).

The findings suggest that melatonin may enhance the expression of H19, THRIL, MALAT, and HOTAIR, as well as NOS activity in macrophages infected with L. major. The upregulation of these lncRNAs by melatonin could potentially improve the macrophages' ability to combat L. major infection.

 The urgent need for antimicrobial research to address the escalating global challenge of β-lactam antibiotic resistance, particularly in Escherichia coli-induced urinary tract infections (UTI), is underscored by the increasing resistance to ciprofloxacin in Latin America. This issue has led to a heightened dependence on alternative therapeutics, such as cephalosporins. The identification of extended-spectrum β-lactamase (ESBL)-producing E. coli, notably the O25b-ST131 clone, adds complexity to UTI management. The prevalence of ESBL-producing E. coli varies globally due to factors including regional antimicrobial usage practices.

 The goal of this study was to identify and molecularly characterize ESBL-producing E. coli isolates to identify the pandemic O25b-ST131 clone related to UTIs in one healthcare institution in Mexico.

 Bacterial species identification and antibiotic susceptibility tests were performed using the VITEK 2. The ESBL genes were identified using polymerase chain reaction (PCR). The E. coli genotyping was carried out by the phylogenetic group analysis and the O25b-ST131 identification.

 A total of 86 unique E. coli isolates were confirmed as ESBL, and 75% were obtained from UTIs. The most prevalent β-lactamase genes were blaCTX-M (66%), blaTEM (8.1%), blaCTX-M/SHV (5.8%), blaCTX-M/TEM (4.6%), and blaSHV (2.3%). The B2 phylogroup was most prominent (54.4%), with 46.5% identified as a globally pandemic O25b-ST131 clone. No evident relationship was observed using random amplified polymorphic DNA (RAPD) between nosocomial and community-acquired infections in ESBL-producing E. coli isolates.

 The obtained findings highlight the significance of monitoring molecular epidemiology in antibiotic resistance profiles of the O25b-ST131 E. coli clone.