Contribution of the gyrA and waaG mutants to fluoroquinolones resistance, biofilm development, and persister cells formation in Salmonella enterica serovar Typhi.

Fluoroquinolone resistance in Salmonella has been reported worldwide and poses a serious public health threat in developing countries. Multiple factors contribute to fluoroquinolone resistance, including mutations in DNA gyrase and the acquisition of antimicrobial resistance genes. Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever in humans, which is highly prevalent in counties with poor sanitation and hygiene standards. Here, we reported S. Typhi clinical isolates that showed varying degrees of susceptibility to fluoroquinolones and were characterized by Analytical Profile Index 20E test kit and 16S rRNA sequencing. S. Typhi strain S27 was resistant to fluoroquinolones and had multiple mutations in the gyrA gene. The gyrA lies in the quinolone resistance determining region of S. Typhi and has mutations at codon 83 (Ser83Phe), codon 87 (Asp87Gly), codon 308 (Lys308Glu), and codon 328 (Val328Ile). S. Typhi strain S6 has no gyrA mutations and is sensitive to fluoroquinolones but forms a strong biofilm relative to S. Typhi S27. Transcriptional analysis of biofilm associated genes revealed that the waaG gene was significantly downregulated. The ΔwaaG mutant showed a significant decrease in persister cells and a strong biofilm formation relative to wild type and gyrA mutant. The gyrA tetra mutant persister assay revealed a significant increase in persister cells compared to wild type and ΔwaaG. Collectively, this is the first report of S. Typhi's two key genes and their roles in antibiotic tolerance, biofilm formation, and fluoroquinolone resistance that can help in understanding the mechanism of persister formation and eradication.

Clinical manifestations of active tuberculosis patients coinfected with severe acute respiratory syndrome coronavirus-2.

Summary background: The coronavirus 2019 pandemic was caused by a new single-strand RNA virus that originated from Wuhan, China, and infected more than 190 countries. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) coinfection with tuberculosis posed a serious public health concern and complicated the prognosis and treatment of patients. Since both are respiratory diseases, the sign and symptoms may overlap and could have synergistic effects on the host that can increase mortality during coinfection. The present investigation reported the clinical characteristics of patients having coinfection of COVID-19 and tuberculosis (COVID-TB). Methods: We performed a retrospective investigation on COVID-19 infection in tuberculosis patients between the years 2020 and 2021. The SARS-CoV-2 was confirmed by PCR and the COVID-TB epidemiological and clinical findings were recorded on the day of admission and followed up for 25 days. Results: The mean age of the COVID-19 patients was 50 ± 15 years, 76.36% were male and 23.64% were female. Weight loss, sore throat, whooping cough, chest pain, and vomiting were common symptoms, and asthma, diabetes, arthritis, and hypertension were found as co-morbidities in COVID-TB. The D-dimer, lactate dehydrogenase, C-reactive protein, erythrocyte sedimentation rate, and creatine kinase levels increased 14-fold, 12.5-fold, 11-fold, 10-fold, and 7-fold respectively during COVID-TB. The patients suffered from hyperferritinemia and lymphocytopenia which increased the likelihood of death. The levels of D-dimer, lactate dehydrogenase, C-reactive protein, erythrocyte sedimentation rate, and creatinine kinase were positively correlated with patient age. The chest radiograph showed the infectious agents have consolidated opacity and peripheral dissemination in the lungs. Conclusion: Tuberculosis coinfection augmented the severity of COVID-19 and the likelihood of death, and high vigilance is recommended for respiratory pathogens in COVID-19.

Bioactive, antioxidant and antimicrobial properties of chemically fingerprinted essential oils extracted from Eucalyptus globulus: in-vitro and in-silico investigations.

Innovative approaches are urgently required to treat divestating bacterial diseases in the face of rising bacterial resistance rates. The current investigative work focused on hydro-distilling Tasmanian blue gum (Eucalyptus globulus) to isolate the essential oil, which was then tested for bioactivity, antioxidant capacity, and antibacterial activity using in-vitro and in silico assays. The antioxidant activity was avualated against DPPH and FRAP. With results of 69.63 RSA (%) (µL/L AAE) at a concentration of 5 mL/L and 51.56 (µL/L AAE) at concentration of 90 ppm in the 2,20-diphenyl-1-picryl hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays, respectively, the extracted oil indicated considerable antioxidant activity. The extracted oil demonstrated powerful antibacterial activity in in-vitro tests against both Gram-positive and Gram-negative bacterial strains, including Bordetella bronchiseptica (21 mm), Staphylococcus epidermidis (19 mm), and Staphylococcus aureus (19 mm), with significant minimal inhibitory (MIC) and minimum bactericidal (MIB) concentrations. Additionally, GC-MS analysis of the oil from E. globulus identified several low-molecular-weight compounds, including Eucalyptol, γ-Terpinene, Shisool acetate, 1,3-trans,5-cis-Octatriene, 2,6-Dimethyl-1,3,5,7-octatetraene, E,E, Cyclohexene, 1-methyl-4-(1-methylethylidene), Benzene, 1-methyl-4-(1-methylethenyl), Butanoic acid, 3-methyl-, 3-methylbutyl ester, and 1,3,8-p-Menthatriene. Several other compounds were also identified, including Fenchol, 2-Methyl-trans-3a,4,7,7a-tetrahydroindane, (E,E,E)-2,4,6-Octatriene, 1,2,3,6-Tetrahydrobenzylalcohol, acetate, Alloaromadendrene, Phenol, 2-ethyl-4,5-dimethyl, Phenol, 2-methyl-5-(1-methylethyl)-, p-Cymen-7-ol, 1,5,5-Trimethyl-6-methylene-cyclohexene, 1,3-Cyclohexadiene, 1-methyl-4-(1-methylethyl)-, 2,6-Octadien-1-ol, 3,7-dimethyl-, acetate, (Z), and more. The bioactive potential of Eucalyptus globulus essential oil against 1AJ6 and 1R4U was highlighted by molecular docking analyses, suggesting its utility as a natural source of antioxidant and antibacterial compounds with the potential to replace chemical disinfectants in a variety of applications.

Burn Wound Microbiology and the Antibiotic Susceptibility Patterns of Bacterial Isolates in Three Burn Units of Abbottabad, Pakistan.

Infection is the leading cause of morbidity and mortality among burn patients and is accentuated multifold by the emergence of antimicrobial resistance among the nosocomial isolates. It is vital to know the common organisms involved in infected burn wound etiology and their respective antibiotic susceptibility patterns. These crucial findings can help in formulating a better and more efficient antimicrobial therapy plan for controlling burn wound infections. The current study was conducted to identify the common bacteria involved in causing infections in wounds of burn patients and their respective antibiotic susceptibility patterns in three hospitals of Abbottabad, Pakistan. A total of 100 patients were included from the burn units of three hospitals in Abbottabad. Wound swabs were taken from the deepest portions of infected burns, and the organisms involved were isolated via standard microbiological techniques. The Kirby-Bauer disc diffusion technique was used to monitor antibiotic susceptibility. Gram-positive organisms were found readily in infected burn wounds. Staphylococcus aureus (46%) was the most common isolate followed by Staphylococcus epidermidis (17%), Escherichia coli (16%), Proteus spp. (12%), Klebsiella pneumoniae (10%), and Pseudomonas aeruginosa, which was only 7%. Gram-positive bacteria were sensitive to amikacin, gentamicin, cefotaxime, and norfloxacin. In contrast, the gram-negative isolates were sensitive to amikacin, chloramphenicol, and nalidixic acid. Pseudomonas was resistant to most of the antibiotics tested in the present study.