Molecular identification and differential proteomics of drug resistant Salmonella Typhi.

This study aimed to elucidate differentially expressed proteins in drug resistant Salmonella Typhi. Among 100 samples, S. typhi were identified in 43 samples. In drug susceptibility profile, 95.3% (41/43), 80% (35/43) and 70% (30/43) resistances were observed against Nalidixic acid, Ampicillin, and Chloramphenicol respectively. No resistance was observed against Imipenum and Azithromycin while only 11% (5/43) isolates were found resistant to Ceftriaxone. Mass spectrometric differential analysis resulted in 23 up-regulated proteins in drug resistant isolates. Proteins found up-regulated are involved in virulence (vipB, galU, tufA, and lpp1), translation (rpsF, rpsG, rplJ, and rplR), antibiotic resistance (zwf, phoP, and ompX), cell metabolism (metK, ftsZ, pepD, and secB), stress response (ridA, rbfA, and dps), housekeeping (gapA and eno) and hypothetical proteins including ydfZ, t1802, and yajQ. These proteins are of diverse nature and functions but highly interconnected. Further characterization may be helpful for elucidation of new biomarker proteins and therapeutic drug targets.

Immunoaffinity-based mass spectrometric characterization of immunoreactive proteins of Salmonella Typhi.

Salmonella Typhi, a human-restricted Gram negative enterobacteriaceae, is the causative agent of typhoid fever in human being. The available serodiagnostic tools for the diagnosis of typhoid fever lack sensitivity and/or specificity. This study aimed to identify the immunoreactive proteins of S. Typhi that could help to develop improved diagnostic tools. Here, we performed immunoaffinity-based proteomic approach that uses charged columns to retrieve IgG and IgM antibodies from the plasma of typhoid patients followed by capture of S. Typhi proteins. These proteins were then characterized by mass spectrometry and bioinformatics tools. Using this approach, we identified 28 immunoreactive proteins of S. Typhi, in which 14 proteins were captured by IgG charged column and 4 proteins were captured by IgM column. We also identified 10 proteins (hlyE, rfbH, dapD, argI, glyA, pflB, trxB, groEL, tufA and pepD) captured by both columns. The prediction of antigenicity and immunogenicity resulted that 22 proteins were antigenic while 6 were non-antigenic on the scale of 0.4 threshold value of VaxiJen. These proteins successfully simulated the immune system in silico and in response higher amount of antibodies' titers were recorded in C-IMMSIM, confirming the immunogenic nature of these proteins. The identified proteins are of diverse nature and functions including those involved in virulence and pathogenesis, energy metabolism, cell development, biosynthesis of amino acids, regulatory functions and biosynthesis of cofactors. The findings of this study would be helpful in the development of improved vaccines and diagnostic tools for typhoid fever.

Analysis of associated risk factors among recurrent cutaneous leishmaniasis patients: A cross-sectional study in Khyber Pakhtunkhwa, Pakistan.

BACKGROUND: Leishmaniasis is the second and fourth highest cause of mortality and morbidity respectively among all tropical diseases. Recurrence in the onset of leishmaniasis is a major problem that needs to be addressed to reduce the case fatality rate and ensure timely clinical intervention. Here we are investigating the association of risk factors with recurrent cutaneous leishmaniasis to address this issue. MATERIAL AND METHODS: Patients received by Nasser Ullah Khan Babar Hospital in Peshawar, Pakistan from March 2019 to July 2020 were enrolled in this study. Those patients who developed symptoms after completion of treatment were included in Group-A while those who had atypical scars like leishmaniasis but were negative for cutaneous leishmaniasis were included in the comparison group tagged as Group B. All those individuals who had completed six weeks of treatment for CL but had normal complete blood counts (CBC) were included to avoid other underlying immunological pathologies, while we excluded those participants who had co-morbidities like diabetes, liver disease, cardiac disease, and pregnant and lactating women through their history Association was tested between Group-A and Group-B with other explanatory variables through chi-square test. The regression model was proposed to determine the predictors. RESULT: A total of 48 participants of both sexes were included in the study with a mean age of 32.2 ± 15.10. The data suggest that females are overrepresented among the patients with recurrent leishmaniasis [21(53.8 %,); p = 0.07]. Compared to patients; healthy participants had a higher proportion of adults (19-59 years) versus adolescents (13-18 years) [26(66.7 %) vs 07(17.9), p = 0.004]. Multivariate logistic regression analysis shows that females are 2.1 times more prone to infections among cases as compared to healthy individuals [unadjusted OR 2.20, 95 % confidence interval (CI) 1.5-10.6, p = 0.02; adjusted OR 2.1, 95 % CI 1.50-10.69, p = 0.02]. We propose that patients receiving intradermal were less likely to be infected as compared to those receiving intralesional injections [unadjusted OR 0.07.0, 95 % confidence interval (CI) 1.18-3.37, p = 0.03; adjusted OR 0.06, 95 % CI 1.18-3.38, p = 0.03]. CONCLUSION: Old age (adults) and sex (females) were the strongest predictors to be associated with recurrent leishmaniasis. Similarly, the choice of intradermal as compared to intralesional injection and the prolonged treatment duration were strongly associated with greater chances of recurrence.

Salmonella Typhi from Northwest Pakistan: Molecular Strain Typing and Drug Resistance Signature.

Objective: To determine the molecular strain typing and drug resistance pattern of Salmonella enterica serovar Typhi prevalent in Northwest Pakistan. Methodology: A total of 2,138 blood samples of suspected typhoid patients from Northwest Pakistan were collected followed by identification of Salmonella Typhi through biochemical, serological, and species-specific fliC-d gene amplification. These isolates were typed by variable-number tandem repeat (VNTR) profiling and investigated for drug resistance. Results: The overall prevalence of Salmonella Typhi was found to be 8.8% (n = 189). Thirty different VNTR strain types of Salmonella Typhi were detected and the most prevalent strain types were T1 and T4, whereas T27 was less prevalent strain. Among the 189 isolates 175 (92.5%) isolates were multidrug resistant, whereas 12 (5.8%) isolates were extensively drug resistant. Resistance to imipenem in Salmonella Typhi was not observed. Most of the isolates have genes encoding for resistance to fluoroquinolones, including gyrA (n = 164), gyrB (n = 160), parC (n = 164), parE (n = 160), ac(6')-ib-cr (n = 163), qnrS (n = 15), and qnrB (n = 3). Similarly, chloramphinicol (cat; n = 147), azithromycin (msrA; n = 3), and co-trimoxazole (dfrA7; n = 145) resistance genes were detected among Salmonella Typhi isolates. Conclusion: In this study, T1 and T4 type Salmonella Typhi strains were predominantly prevalent in Northwest Pakistan. Antibiotic resistance among Salmonella Typhi isolates were observed. Findings of the study would be helpful to devise an appropriate antibiotic policy to control the emergence of drug-resistant Salmonella Typhi in Pakistan.