The rise of anthropogenic activities has resulted in the increasing release of various contaminants into the environment, jeopardizing fragile ecosystems in the process. Heavy metals are one of the major pollutants that contribute to the escalating problem of environmental pollution, being primarily introduced in sensitive ecological habitats through industrial effluents, wastewater, as well as sewage of various industries. Where heavy metals like zinc, copper, manganese, and nickel serve key roles in regulating different biological processes in living systems, many heavy metals can be toxic even at low concentrations, such as mercury, arsenic, cadmium, chromium, and lead, and can accumulate in intricate food chains resulting in health concerns. Over the years, many physical and chemical methods of heavy metal removal have essentially been investigated, but their disadvantages like the generation of chemical waste, complex downstream processing, and the uneconomical cost of both methods, have rendered them inefficient,. Since then, microbial bioremediation, particularly the use of bacteria, has gained attention due to the feasibility and efficiency of using them in removing heavy metals from contaminated environments. Bacteria have several methods of processing heavy metals through general resistance mechanisms, biosorption, adsorption, and efflux mechanisms. Bacillus spp. are model Gram-positive bacteria that have been studied extensively for their biosorption abilities and molecular mechanisms that enable their survival as well as their ability to remove and detoxify heavy metals. This review aims to highlight the molecular methods of Bacillus spp. in removing various heavy metals ions from contaminated environments.

Salmonella Typhi is a Gram-negative pathogen that causes typhoid fever in humans. The use of antibiotics to treat typhoid has considerably mitigated its fatality risk, but rising multidrug-resistant (MDR) and extensively drug-resistant (XDR) resistance in Pakistan threatens effective treatment. This study determined the prevalence of MDR and XDR S. Typhi at a local hospital in Lahore. Blood samples (n = 3000) were obtained and processed for bacterial identification. Antibiotic susceptibility test was performed using VITEK^® 2 Compound 30 System. Statistical data analysis was performed using a Mann–Whitney U and Kruskal–Wallis H test, respectively. The results revealed 600 positive cultures, of which the majority were found to be XDR S. Typhi (46.1%) and MDR S. Typhi (24.5%) strains. The disease burden of resistant Salmonella strains was greater in males (60.67%) than females (39.33%), with the most affected age group being 0–10 years old (70.4 %). In both the outpatient department (OPD) and general ward, the prevalence of XDR S. Typhi cases was found to be alarmingly high (48.24%), followed by MDR S. Typhi (25.04 %). The results of the statistical analysis demonstrated that the incidence of resistance in MDR and XDR S. Typhi strains was not affected by the age as well as the gender of patients (p > 0.05). The occurrence of resistant strains against four tested antibiotics (azithromycin, ciprofloxacin, imipenem, and meropenem) was found to be similar in different wards and among hospitalized and OPD patients (p > 0.05). Maximum resistance was observed against chloramphenicol and ampicillin in the OPD and pediatric ward. Piperacillin/Tazobactam was observed to be the most effective antibiotic, followed by co-amoxiclav (p < 0.001). This study is effective in validating the existence of MDR and XDR S. Typhi in Lahore, where stringent methods should be applied for controlling its spread.

Salmonella enterica serovar Typhi (S. Typhi) is a Gram-negative pathogen that causes typhoid fever in humans. Though many serotypes of Salmonella spp. are capable of causing disease in both humans and animals alike, S. Typhi and S. Paratyphi are common in human hosts only. The global burden of typhoid fever is attributable to more than 27 million cases each year and approximately 200,000 deaths worldwide, with many regions such as Africa, South and Southeast Asia being the most affected in the world. The pathogen is able to cause disease in hosts by evading defense systems, adhesion to epithelial cells, and survival in host cells in the presence of several virulence factors, mediated by virulence plasmids and genes clustered in distinct regions known as Salmonella pathogenicity islands (SPIs). These factors, coupled with plasmid-mediated antimicrobial resistance genes, enable the bacterium to become resistant to various broad-spectrum antibiotics used in the treatment of typhoid fever and other infections caused by Salmonella spp. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains in many countries of the world has raised great concern over the rise of antibiotic resistance in pathogens such as S. Typhi. In order to identify the key virulence factors involved in S. Typhi pathogenesis and infection, this review delves into various mechanisms of virulence, pathogenicity, and antimicrobial resistance to reinforce efficacious disease management.

The incessant pervasiveness of heavy metals in the environment is one of the precursory factors of pollution. This research study was endeavored upon to investigate the bioremediation potential of a nickel (Ni)-resistant bacterial isolate, identified as Bacillus altitudinis MT422188, whose optimum growth parameters were demonstrated at pH 7, temperature 32 °C, and 1 mM phosphate. Minimal Inhibitory Concentration (MIC) and EC₅₀ for Ni were observed to be 20 and 11.5 mM, respectively, whereas the cross heavy-metal resistance was discerned as Cu²⁺ (25 mM) > Zn²⁺ (15 mM) > Cr⁶⁺ (10 mM) > Pb²⁺ (5 mM) > Co²⁺ (8 mM) > Cd²⁺ (3 mM) > Hg²⁺ (0 mM). Ni biosorption studies by live and heat-killed bacterial cells were suggestive of Ni uptake being facilitated by an ATP-independent efflux system. A pilot-scale study displayed the effective removal of Ni (70 mg/L and 85 mg/L) at 4- and 8-day intervals, respectively. Moreover, chemotaxis and motility assays indicated the role of Ni as a chemoattractant for bacterial cells. The presence of Ni reduced the GR (0.001 ± 0.003 Ug⁻¹FW), POX (0.001 ± 0.001 Ug⁻¹FW), and SOD (0.091 ± 0.003 Ug⁻¹FW) activity, whereas Sodium dodecyl sulphate—Polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of metallothionein (60 kDa). Kinetic and isotherm studies suggested a pseudo second-order and Freundlich model to be better fitted for our study. The thermodynamic parameters (∆H° = 3.0436 kJ/mol, ∆S° = 0.0224 kJ/mol/K) suggested the process to be endothermic, spontaneous, and favorable in nature. FTIR analysis elucidated the interaction of hydroxyl and carboxyl groups with Ni. Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) demonstrated changes in the morphological and elemental composition of the bacterial cells, which affirmed their interaction with Ni during biosorption. In summary, our study concludes the efficient role of Bacillus altitudinis MT422188 in removing Ni from polluted industrial effluents.

Among oral diseases, dental caries is one of the most frequent to affect human health. The current research work aimed to ascertain the antibacterial, anti-biofilm, and antioxidative potential of Piper betle leaf extract against bacteria isolated from dental caries. Analysis for the presence of phytochemical compounds revealed compounds, such as tannins, steroids, phenolic compounds, and alkaloids, which were also confirmed by TLC and FTIR. GC-MS analysis elucidated the presence of 20 phytocompounds, among which were some well-reported bioactive compounds. The chloroform extract of P. betle demonstrated good antibacterial activity (7 mm) and minimum inhibitory concentration (MIC) (100 mg mL⁻¹) against Bacillus gaemokensis MW067143, which was the frequent biofilm producer among isolated bacterial strains. Fractions of the extract were isolated through column chromatography, after which the antibacterial activity was again evaluated. Spirost-8-en-11-one,3-hydroxy(3β,5α,14β,20β,22β,25R), an oxosteroid in nature, was observed to exhibit remarkable antibacterial potential (12 mm) against B. gaemokensis. Bacterial cells treated with P. betle extract had elevated SOD, APOX, POX, and GR activity, while its proteolytic activity against whole bacterial proteins was pronounced with the suppression of several proteins (50, 40, 15, and 10 kDa) in SDS-PAGE. Bacterial cells treated with P. betle extract demonstrated decreased growth, while the extract was also observed to exhibit inhibition of biofilm formation (70.11%) and demolition of established B. gaemokensis biofilms (57.98%). SEM analysis revealed significant changes to bacterial morphology post treatment with P. betle, with cellular disintegration being prominent. In silico network pharmacology analysis elucidated proteins like ESR1 and IL6 to be majorly involved in biological pathways of dental caries, which also interact with the protective ability of P. betle. Gene Ontology (GO) terms and KEGG pathways were also screened using enrichment analysis. Molecular docking demonstrated the highest binding affinity of Spirost-8-en-11-one,3-hydroxy-,(3β,5α,14β,20β,22β,25R) with bacterial proteins FabI (−12 kcal/mol), MurB (−17.1 kcal/mol), and FtsZ (−14.9 kcal/mol). Therefore, it is suggested that P. betle can serve a potentially therapeutic role and could be used in the preparation of herbal formulations for managing bacterial flora.

The current research focused on studying the pattern of catheter-related bloodstream infections (CRBSI) with femoral central access versus internal jugular access in patients admitted to the medical intensive care unit (ICU). A cross-sectional study was conducted at the Department of Emergency Medicine, Shifa International Hospital, between March 4, 2022, and August 4, 2022. All individuals who presented to the ICU who needed a central venous catheter (CVC) for more than 48 hours were included. Catheter insertion was not permitted if the patient had a history of dermatitis or burns at the site of insertion or if the hemodialysis procedure necessitated the insertion of the catheter into a blood vessel. Three groups of patients were created: group A patients had been diagnosed with CRBSI; group B patients had catheter colonization (CC); and group C did not have CRBSI or CC. Standard microbiological methods were used to identify all of the bacteria collected from the cultures. All data was documented in a predefined pro forma. Overall, 20 (12.12%) patients had positive CRBSI, 68 (41.5%) had CC, and the remaining 46.3% of cultures were negative. Elderly populations were more prone to acquiring CRBSI showing a significant correlation between older age and CRBSI (p < 0.0001). CC was significantly associated with a longer duration of ICU stay, i.e., 30.3 ± 3.7 (p = 0.003). The absence of both CRBSI and CC was significantly associated with a lower duration of catheterization (11 ± 8.5 days in group C versus 22.1 ± 6.9 and 18.7 ± 7 days in groups A and B, respectively; p < 0.0001). Our study revealed a higher risk of CRBSI when the femoral access was compared to the internal jugular access (58.3% vs. 41.7%; p = 0.0008). The study did not find any significant association of CC with femoral or internal jugular access. Furthermore, a significantly higher rate of negative cultures was reported in patients with internal jugular access as compared to femoral vein access (85.8% vs. 14.2%; p = 0.007). The need for routinely monitoring and observing the microbiological spectrum in patients receiving care in intensive care units is highlighted by the current investigation. The patients with internal jugular vein access had a decreased incidence of CRBSI and CC, while those with femoral access experienced CRBSI more frequently. Escherichia coli and Pseudomonas aeruginosa were the most frequently isolated germs, and both were resistant to various drugs that are used today. It is essential to regularly monitor the epidemiology of CRBSI in order to adopt preventative measures for infection prevention and control, such as staff education, strict hygiene standards, and a higher nurse-to-patient ratio.