Microbial exopolysaccharides (EPSs), having great structural diversity, have gained tremendous interest for their prebiotic effects. In the present study, mice models were used to investigate if microbial dextran and inulin-type EPSs could also play role in the modulation of microbiomics and metabolomics by improving certain biochemical parameters, such as blood cholesterol and glucose levels and weight gain. Feeding the mice for 21 days on EPS-supplemented feed resulted in only 7.6 ± 0.8% weight gain in the inulin-fed mice group, while the dextran-fed group also showed a low weight gain trend as compared to the control group. Blood glucose levels of the dextran- and inulin-fed groups did not change significantly in comparison with the control where it increased by 22 ± 5%. Moreover, the dextran and inulin exerted pronounced hypocholesterolemic effects by reducing the serum cholesterol levels by 23% and 13%, respectively. The control group was found to be mainly populated with Enterococcus faecalis, Staphylococcus gallinarum, Mammaliicoccus lentus and Klebsiella aerogenes. The colonization of E. faecalis was inhibited by 59–65% while the intestinal release of Escherichia fergusonii was increased by 85–95% in the EPS-supplemented groups, respectively, along with the complete inhibition of growth of other enteropathogens. Additionally, higher populations of lactic acid bacteria were detected in the intestine of EPS-fed mice as compared to controls.

Typhoid fever, caused by Salmonella enterica subsp. enterica serovar Typhi (S. typhi), remains a major public health concern, particularly in low-resource settings with poor sanitation. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains have significantly complicated treatment, especially in vulnerable pediatric populations. This study aimed to characterize the genetic profiles of drug resistance in MDR and XDR S. typhi isolates from pediatric patients. Methods: A cross-sectional study was conducted on 800 blood samples from pediatric typhoid patients. S. typhi isolates were identified using the BacT/ALERT 3D system, followed by culture on MacConkey and blood agar. Antimicrobial susceptibility was assessed using the disk diffusion method according to CLSI 2022 guidelines. Whole-genome sequencing (WGS) was performed on 29 isolates using Illumina MiSeq technology, and resistance genes and mutations were analyzed. Results: Antimicrobial susceptibility testing revealed that 68 (48.57%) of S. typhi isolates were XDR and 61 (43.57%) were MDR, exhibiting widespread resistance to ciprofloxacin, ampicillin, chloramphenicol, ceftriaxone, and co-trimoxazole. WGS identified key resistance genes across all 29 isolates, including bla_CTX-M-15, bla_TEM-1B, qnrS1, aac(6′)-Iaa, catA1, dfraA7, sul1, qacEΔ1, and the gyrA-S83F mutation. Notably, gyrA-S83F and qnrS1 were detected in all isolates and strongly correlated with ciprofloxacin resistance. Virulence genes were consistently present in all isolates, indicating a high pathogenic potential. The IncY plasmid, found in four (14%) isolates, was linked to resistance against third-generation cephalosporins, including ceftriaxone. Conclusion: This study underscores the alarming prevalence of MDR and XDR S. typhi isolates among pediatric patients, driven by resistance genes such as bla_CTX-M-15, bla_TEM-1B, and gyrA-S83F. These findings highlight the urgent need for targeted therapeutic strategies and robust surveillance systems to combat the growing threat of drug-resistant typhoid fever.

Background: Wastewater is a major source of Antibiotic-Resistant Bacteria (ARB) and a hotspot for the exchange of Antibiotic-Resistant Genes (ARGs). The occurrence of Carbapenem-Resistant Bacteria (CRB) in wastewater samples is a major public health concern. Objectives: This study aimed to analyze Antibiotic resistance in bacteria from wastewater sources in Pakistan. Methods: We analyzed 32 bacterial isolates, including 18 Escherichia coli, 4 Klebsiella pneumoniae, and 10 other bacterial isolates using phenotypic antibiotic susceptibility assay and whole-genome sequencing. This study identified the ARGs, plasmid replicons, and integron genes cassettes in the sequenced isolates. One representative isolate was further sequenced using Illumina and Oxford nanopore sequencing technologies. Results: Our findings revealed high resistance to clinically important antibiotics: 91% of isolates were resistant to cefotaxime, 75% to ciprofloxacin, and 62.5% to imipenem, while 31% showed non-susceptibility to gentamicin. All E. coli isolates were resistant to cephalosporins, with 72% also resistant to carbapenems. Sequence analysis showed a diverse resistome, including carbapenamases (blaNDM-5, blaOXA-181), ESBLs (blaCTX-M-15, blaTEM), and AmpC-type β-lactamases (blaCMY). Key point mutations noticed in the isolates were pmrB_Y358N (colistin) and ftsI_N337NYRIN, ftsI_I336IKYRI (carbapenem). The E. coli isolates had 11 different STs, with ST410 predominating (28%). Notably, the E. coli phylogroup A isolate 45EC1, (ST10886) is reported for the first time from wastewater, carrying blaNDM-5, blaCMY-16, and pmrB_Y358N with class 1 integron gene cassette of dfrA12-aadA2-qacEΔ1 on a plasmid-borne contig. Other carbapenamase, blaNDM-1 and blaOXA-72, were detected in K. pneumoniae 22EB1 and Acinetobacter baumannii 51AC1, respectively. The integrons with the gene cassettes encoding antibiotic resistance, and the transport and bacterial mobilization protein, were identified in the sequenced isolates. Ten plasmid replicons were identified, with IncFIB prevalent in 53% of isolates. Combined Illumina and Oxford nanopore sequencing revealed blaNDM-5 on an IncFIA/IncFIC plasmid and is identical to those reported in the USA, Myanmar, and Tanzania. Conclusions: These findings highlight the environmental prevalence of high-risk and WHO-priority pathogens with clinically important ARGs, underscoring the need for a One Health approach to mitigate ARB isolates.