Biological Removal of Nitrates from Groundwater Resources in Saudi Arabia

Groundwater is the main water source for many areas in Saudi Arabia and the only source of water in some areas. Many local studies have reported that high nitrate concentrations in some wells of groundwater. To provide safe drinking water, the excess amounts of nitrate have to be removed by bio-denitrification process. This study aims to develop a denitrifying biological filter using denitrifying bacteria immobilized on microbial cellulose for the removal of nitrates from water contaminated with nitrate. Denitrifying bacteria that can form biofilter on microbial cellulose were isolated from different regions in Saudi Arabia and were characterized by molecular techniques. They were evaluated for their ability to analyze nitrates and to develop biofilter to remove nitrates from contaminated water. In the results of this project, an optimal microbial cellulose production was achieved by Gluconacetobacter xylinus ATCC 23768 in the lab, which had facilitated the use of biofilter with the immobilized nitrate-reducing bacteria Pseudomonas aeruginosa. The reduction rate of nitrate was reached 1.9mg/L from the starting concentration of 100 mg/L after 18h. Promising results of nitrate removal rate on MC immobilized with Pseudomonas aeruginosa on biofilter at optimized lab conditions of pH, and proper carbon source were achieved. The results suggest that water contaminated with nitrate can be removed by the bio-denitrification process effectively

The emergence of a novel sequence type of MDR Acinetobacter baumannii from the intensive care unit of an Egyptian tertiary care hospital

Abstract Background and aim of work Acinetobacter baumannii is known for nosocomial outbreaks worldwide. In this study, we aimed to investigate the antibiotic susceptibility patterns and the clonal relationship of A. baumannii isolates from the intensive care unit (ICU) of an Egyptian hospital. Methods In the present study, 50 clinical isolates of multidrug resistant (MDR)-A. baumannii were obtained from patients admitted into the ICU from June to December 2015. All isolates were analyzed for antimicrobial susceptibilities. Multiplex PCR was performed to detect genes encoding oxacillinase genes (bla OXA-51-like, bla OXA-23-like, bla OXA-24-like, and bla OXA-58-like). Multilocus sequence typing (MLST) based on the seven-gene scheme (gltA, gyrB, gdhB, recA, cpn60, gpi, rpoD) was used to examine these isolates. Results All A. baumannii clinical isolates showed the same resistance pattern, characterized by resistance to most common antibiotics including imipenem (MIC ≥ 8μ/mL), with the only exception being colistin. Most isolates were positive for bla OXA-51-like and bla OXA-23-like (100 and 96%, respectively); however, bla OXA-24-like and bla OXA-58-like were not detected. MLST analysis identified different sequence types (ST195, ST208, ST231, ST441, ST499, and ST723) and a new sequence type (ST13929) with other sporadic strains. Conclusions MDR A. baumannii strains harboring bla OXA-23-like genes were widely circulating in this ICU. MLST was a powerful tool for identifying and epidemiologically typing our strains. Strict infection control measures must be implemented to contain the worldwide spread of MDR A. baumannii in ICUs

The Delivery of the Novel Drug ‘Halicin’ Using Electrospun Fibers for the Treatment of Pressure Ulcer against Pathogenic Bacteria

Pressure ulcer or bedsore is a form of skin infection that commonly occurs with patients admitted to the hospital for an extended period of time, which might lead to severe complications in the absence of medical attention, resulting in infection either by drug-sensitive or drug-resistant bacteria. Halicin, a newly discovered drug effective against several bacterial strains, including multidrug-resistant bacteria, was investigated to reduce bacterial infection burden. This study aims to formulate halicin into electrospun fibers to be applied in bedsores as antibacterial dressing to assess its efficacy against gram-positive (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli and Acinetobacter baumannii) by studying the minimum inhibitory concentration (MIC) and bacterial zone of inhibition assays. The diameters of inhibition growth zones were measured, and the results have shown that the drug-loaded fibers were able to inhibit the growth of bacteria compared to the halicin discs. The release profile of the drug-loaded fibers exhibited a complete release of the drug after 2 h. The results demonstrated that the drug-loaded fibers could successfully release the drug while retaining their biological activity and they may be used as a potential antimicrobial dressing for patients with pressure ulcers caused by multidrug resistant bacteria

Formulation and Evaluation of Alcohol-Free Hand Sanitizer Gels to Prevent the Spread of Infections during Pandemics

Hand hygiene is an essential factor to prevent or minimize the spread of infections. The ability to prepare an alcohol-free hand sanitizer (AFHS) with antimicrobial properties is crucial, especially during pandemics, when there are high demands and a low supply chain for ethanol and isopropanol. The objective of this study was to prepare AFHS gels based on natural materials that contain essential oils (EOs) that would be effective against a broad spectrum of pathogens. The results showed that the organoleptic characteristics of all prepared hand sanitizer gels were considered acceptable. The pH of the formulations was slightly acidic (circa 3.9) owing to the presence of aloe vera in large proportions (90% v/v), which is known for its acidity. The spreadability for all tested formulations was in the acceptable range. The antimicrobial effectiveness test demonstrated that the prepared hand sanitizer gels had antimicrobial activities against different gram-positive and gram-negative bacteria and Candida albicans yeast. The highest antibacterial effect was observed with tea tree oil hand sanitizers, which lack activity against the yeast, while clove oil hand sanitizers showed effectiveness against all microorganisms, including Candida albicans. The lavender hand sanitizer exhibited the least antimicrobial efficiency. The acceptability study on 20 human volunteers showed that the hand sanitizer gel containing 1.25% (v/v) clove oil did not produce any signs of skin irritation. This study suggested that the prepared natural hand sanitizer gel with 1.25% (v/v) clove oil can be a potential alternative to commonly used alcohol-based hand sanitizers (ABHS)

Evaluation of Xpert MTB/RIF Ultra for the Diagnosis of Extrapulmonary Tuberculosis: A Retrospective Analysis in Saudi Arabia

Abstract The incidence of extrapulmonary tuberculosis (EPTB) in low- and middle-income countries, as well as, high-income countries has increased over the last two decades. The acid-fast bacillus (AFB) smear test is easy to perform and cost-effective with a quick turnaround time but the test has low sensitivity. Culture remains the gold standard for detecting TB; however, it has low sensitivity and slow bacterial growth patterns, as it may take up to 6 to 8 weeks to grow. Therefore, a rapid detection tool is crucial for the early initiation of treatment and ensuring an improved therapeutic outcome. Here, the Xpert Ultra system was developed as a nucleic acid amplification technique to accelerate the detection of MTB in paucibacillary clinical samples and endorsed by the World Health Organization. From March 2020 to August 2021, Xpert Ultra was evaluated for its sensitivity and specificity against EPTB and compared with those of the routinely used Xpert, culture, and AFB tests in 845 clinical samples in Saudi Arabia. The results indicate the overall sensitivity and specificity of Xpert Ultra to be 91% and 95%, respectively, compared with the Xpert (82% and 99%, respectively) and AFB smear (18% and 100%, respectively) tests. The results also indicated that despite the low microbial loads that were categorized as trace, very low, or low on Xpert Ultra, yet, complete detection was achieved with some sample types (i.e., 100% detection). Consequently, Xpert Ultra has great potential to replace conventional diagnostic approaches as a standard detection method for EPTB

Development and Validation of Reverse Transcriptase Loop-Mediated Isothermal Amplification (RT-LAMP) as a Simple and Rapid Diagnostic Tool for SARS-CoV-2 Detection

Since the COVID-19 pandemic outbreak in the world, many countries have searched for quick diagnostic tools to detect the virus. There are many ways to design diagnostic assays; however, each may have its limitations. A quick, sensitive, specific, and simple approach is essential for highly rapidly transmitted infections, such as SARS-CoV-2. This study aimed to develop a rapid and cost-effective diagnostic tool using a one-step Reverse Transcriptase Loop-Mediated Isothermal Amplification (RT-LAMP) approach. The results were observed using the naked eye within 30–60 min using turbidity or colorimetric analysis. The sensitivity, specificity, and lowest limit of detection (LoD) for SARS-CoV-2 RNA against the RT-LAMP assay were assessed. This assay was also verified and validated against commercial quantitative RT-PCR used by health authorities in Saudi Arabia. Furthermore, a quick and direct sampling from the saliva, or buccal cavity, was applied after simple modification, using proteinase K and heating at 98 °C for 5 min to avoid routine RNA extraction. This rapid single-tube diagnostic tool detected COVID-19 with an accuracy rate of 95% for both genes (ORF1a and N) and an LoD for the ORF1a and N genes as 39 and 25 copies/reaction, respectively. It can be potentially used as a high-throughput national screening for different respiratory-based infections within the Middle East region, such as the MERS virus or major zoonotic pathogens such as Mycobacterium paratuberculosis and Brucella spp., particularly in remote and rural areas where lab equipment is limited

Liposome-Encapsulated Tobramycin and IDR-1018 Peptide Mediated Biofilm Disruption and Enhanced Antimicrobial Activity against Pseudomonas aeruginosa

The inadequate eradication of pulmonary infections and chronic inflammation are significant complications in cystic fibrosis (CF) patients, who usually suffer from persistent and frequent lung infections caused by several pathogens, particularly Pseudomonas aeruginosa (P. aeruginosa). The ability of pathogenic microbes to protect themselves from biofilms leads to the development of an innate immune response and antibiotic resistance. In the present work, a reference bacterial strain of P. aeruginosa (PA01) and a multidrug-resistant isolate (MDR 7067) were used to explore the microbial susceptibility to three antibiotics (ceftazidime, imipenem, and tobramycin) and an anti-biofilm peptide (IDR-1018 peptide) using the minimum inhibition concentration (MIC). The most effective antibiotic was then encapsulated into liposomal nanoparticles and the IDR-1018 peptide with antibacterial activity, and the ability to disrupt the produced biofilm against PA01 and MDR 7067 was assessed. The MIC evaluation of the tobramycin antibacterial activity showed an insignificant effect on the liposomes loaded with tobramycin and liposomes encapsulating tobramycin and IDR-1018 against both P. aeruginosa strains to free tobramycin. Nevertheless, the biofilm formation was significantly reduced (p < 0.05) at concentrations of ≥4 μg/mL and ≤32 μg/mL for PA01 and ≤32 μg/mL for MDR 7067 when loading tobramycin into liposomes, with or without the anti-biofilm peptide compared to the free antibiotic, empty liposomes, and IDR-1018-loaded liposomes. A tobramycin concentration of ≤256 µg/mL was safe when exposed to a lung carcinoma cell line upon its encapsulation into the liposomal formulation. Tobramycin-loaded liposomes could be a potential candidate for treating lung-infected animal models owing to the high therapeutic efficacy and safety profile of this system compared to the free administration of the antibiotic

Identification and Characterization of Plasmids and Genes from Carbapenemase-Producing Klebsiella pneumoniae in Makkah Province, Saudi Arabia

Klebsiella pneumoniae (K. pneumoniae) is involved in several hospital and community-acquired infections. The prevalence of K. pneumoniae-producing-carbapenemase (KPC) resistance genes rapidly increases and threatens public health worldwide. This study aimed to assess the antibiotic resistance level of K. pneumoniae isolates from Makkah Province, Saudi Arabia, during the Islamic ‘Umrah’ ritual and to identify the plasmid types, presence of genes associated with carbapenem hydrolyzing enzymes, and virulence factors. The phenotypic and genotypic analyses based on the minimum inhibitory concentration (MIC), biofilm formation, PCR, and characterization of KPC-encoding plasmids based on the replicon typing technique (PBRT) were explored. The results showed that most isolates were resistant to carbapenem antibiotics and other antibiotics classes. This study identified sixteen different replicons of plasmids in the isolates and multiple genes encoding carbapenem factors, with blaVIM and blaOXA-48 being the most prevalent genes identified in the isolates. However, none of the isolates exhibited positivity for the KPC production activity. In addition, this study also identified six virulence-related genes, including kfu, wabG, uge, rmpA, fimH, and a capsular polysaccharide (CPS). Together, the data reported in this study indicate that the isolated K. pneumoniae during the pilgrimage in Makkah were all resistant to carbapenem antibiotics. Although the isolates lacked KPC production activity, they carried multiple carbapenem-resistant genes and virulence factors, which could drive their resistant phenotype. The need for specialized methods for KPC detection, monitoring the possibility of nosocomial transmission, and diverse therapeutic alternatives are necessary for controlling the spreading of KPC. This study can serve as a reference for clinicians and researchers on types of K. pneumoniae commonly found during religious gathering seasons in Saudi Arabia