Integrated water quality dynamics in Wadi Hanifah: Physical, chemical, and biological perspectives.

The Wadi Hanifah, a crucial aquatic ecosystem, has unfavorable consequences from natural occurrences and human activities. Recognizing the critical need for sustainable water management, this study provides an in-depth evaluation of wadi water quality. A comprehensive assessment was conducted, analyzing physical properties (temperature, pH, electrical conductivity, turbidity, color, and odor), chemical constituents (nitrogen compounds, ion concentrations, heavy metals), and bacterial diversity. The study found significant temperature fluctuations, particularly in sun-exposed or stagnant water areas. The water exhibited slight alkalinity and variable electrical conductivity and turbidity, indicating differing pollution levels. High ammonia and heavy metal concentrations suggested organic and industrial contamination, respectively. In addition, the prevalent fecal-indicator bacteria pointed to possible sewage or agricultural runoff. The research highlights the complex interplay of natural and anthropogenic factors affecting Wadi Hanifah's water quality. It emphasizes the need for location-specific environmental management strategies focusing on pollution control and conservation to safeguard the wadi's ecological health. This study provides vital insights for effective water resource management in Wadi Hanifah, serving as a model for similar ecosystems.

Direct monitoring of meropenem therapeutic efficacy against Klebsiella pneumoniae respiratory infection by bioluminescence imaging.

Introduction. Klebsiella pneumoniae is a major threat to public health worldwide. It is the causative agent for multiple disease presentations including urinary tract infection, septicemia, liver abscess, wound infection and respiratory tract infection. K. pneumoniae causes community- and hospital-acquired pneumonia, which is a devastating disease associated with high mortality rates.Hypothesis. There is a growing concern about the emergence of multidrug-resistant K. pneumoniae strains complicating the treatment with the current available therapeutics; therefore, there is an urgent need for the development of new antimicrobial agents.Aim. K. pneumoniae causes an acute respiratory disease in mice and in the current work we investigated the capability to perform non-invasive monitoring of bioluminescent Klebsiella to monitor therapeutic efficacy.Methodology. We engineered a bioluminescence reporter strain of K. pneumoniae to monitor the impact of antibiotics in a murine respiratory disease model.Results. We demonstrate that bioluminescence correlates with bacterial numbers in host tissues allowing for a non-invasive enumeration of bacterial replication in vivo. Light production is directly linked to bacterial viability, and this novel bioluminescent K. pneumoniae strain enabled monitoring of the efficacy of meropenem therapy in arresting bacterial proliferation in the lung.Conclusion. The use of non-invasive bioluminescent imaging improves preclinical animal model testing to detect study outcome earlier and with higher sensitivity.

Microbial Diversity of Some Sabkha and Desert Sites in Saudi Arabia.

Several studies isolated fungal and bacterial species from extreme environments, such as Sabkha and hot deserts, as their natural habitat, some of which are of medicinal importance. Current research aimed investigating the microbial (fungi and bacteria) diversity and abundance in Sabkha and desert areas in Saudi Arabia. Soil samples from nine different geographical areas (Al-Aushazia lake, AlQasab, AlKasar, Tabuk, Al-Kharj, Al-Madina, Jubail, Taif and Abqaiq) were collected and cultured for microbial isolation. Isolated fungi and bacteria were identified by molecular techniques (PCR and sequencing). Based on 18S rDNA sequencing, 203 fungal species belonging to 33 genera were identified. The most common fungal genera were Fusarium, Alternaria, Chaetomium, Aspergillus Cochliobolus and Pencillium, while the most common species were Chaetomium globosum and Fusarium oxysporum. By 16S rDNA sequencing 22 bacterial species belonging to only two genera, Bacillus and Lactobacillus, were identified. The most commonly isolated bacterial species were Bacillus subtilis and Lactobacillus murinus. Some fungal species were confined to specific locations, such as Actinomyces elegans, Fusarium proliferatum, Gymnoascus reesii and Myzostoma spp. that were only isolated from Al-Aushazia soil. AlQasab soil had the highest microbial diversity among other areas with abundances of 23.5% and 4.4% of total fungi, and bacteria, respectively. Findings of this study show a higher degree of fungal diversity than that of bacteria in all studied areas. Further studies needed to investigate the connection between some isolated species and their habitat ecology, as well as to identify those of medicinal importance.

Validation of 2-18F-Fluorodeoxysorbitol as a Potential Radiopharmaceutical for Imaging Bacterial Infection in the Lung.

2-18F-fluorodeoxysorbitol (18F-FDS) has been shown to be a promising agent with high selectivity and sensitivity in imaging bacterial infection. The objective of our study was to validate 18F-FDS as a potential radiopharmaceutical for imaging bacterial infection longitudinally in the lung. Methods: Albino C57 female mice were intratracheally inoculated with either live or dead Klebsiella pneumoniae to induce either lung infection or lung inflammation. One group of mice was imaged to monitor disease progression. PET/CT was performed on days 0, 1, 2, and 3 after inoculation using either 18F-FDS or 18F-FDG (n = 12 for each tracer). The other group was first screened by bioluminescent imaging (BLI) to select only mice with visible infection (region of interest > 108 ph/s) for PET/CT imaging with 18F-FDS (n = 12). For the inflammation group, 5 mice each were imaged with PET/CT using either 18F-FDS or 18F-FDG from days 1 to 4 after inoculation. Results: For studies of disease progression, BLI showed noticeable lung infection on day 2 after inoculation and significantly greater infection on day 3. Baseline imaging before inoculation showed no focal areas of lung consolidation on CT and low uptake in the lung for both PET radiotracers. On day 2, an area of lung consolidation was identified on CT, with a corresponding 2.5-fold increase over baseline for both PET radiotracers. On day 3, widespread areas of patchy lung consolidation were found on CT, with a drastic increase in uptake for both 18F-FDS and 18F-FDG (9.2 and 3.9). PET and BLI studies showed a marginal correlation between 18F-FDG uptake and colony-forming units (r = 0.63) but a much better correlation for 18F-FDS (r = 0.85). The uptake ratio of infected lung over inflamed lung was 8.5 and 1.7 for 18F-FDS and 18F-FDG on day 3. Conclusion: Uptake of both 18F-FDS and 18F-FDG in infected lung could be used to track the degree of bacterial infection measured by BLI, with a minimum detection limit of 107 bacteria. 18F-FDS, however, is more specific than 18F-FDG in differentiating K. pneumoniae lung infection from lung inflammation.

Abnormal epithelial structure and chronic lung inflammation after repair of chlorine-induced airway injury.

Chlorine is a toxic gas used in a variety of industrial processes and is considered a chemical threat agent. High-level chlorine exposure causes acute lung injury, but the long-term effects of acute chlorine exposure are unclear. Here we characterized chronic pulmonary changes following acute chlorine exposure in mice. A/J mice were exposed to 240 parts per million-hour chlorine or sham-exposed to air. Chlorine inhalation caused sloughing of bronchial epithelium 1 day after chlorine exposure, which was repaired with restoration of a pseudostratified epithelium by day 7. The repaired epithelium contained an abnormal distribution of epithelial cells containing clusters of club or ciliated cells rather than the uniformly interspersed pattern of these cells in unexposed mice. Although the damaged epithelium in A/J mice was repaired rapidly, and minimal airway fibrosis was observed, chlorine-exposed mice developed pneumonitis characterized by infiltration of alveoli with neutrophils and prominent, large, foamy macrophages. Levels of CXCL1/KC, CXCL5/LPS-induced CXC chemokine, granulocyte colony-stimulating factor, and VEGF in bronchoalveolar (BAL) fluid from chlorine-exposed mice showed steadily increasing trends over time. BAL protein levels were increased on day 4 and remained elevated out to day 28. The number of bacteria cultured from lungs of chlorine-exposed mice 4 wk after exposure was not increased compared with sham-exposed mice, indicating that the observed pneumonitis was not driven by bacterial infection of the lung. The results indicate that acute chlorine exposure may cause chronic abnormalities in the lungs despite rapid repair of injured epithelium.

Intubation-mediated intratracheal (IMIT) instillation: a noninvasive, lung-specific delivery system.

Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences between the murine and human respiratory systems, especially in their upper respiratory tracts (URT). In some models, these differences in the murine nasal cavity can have a significant impact on disease progression and presentation in the lower respiratory tract (LRT) when using intranasal instillation techniques, potentially limiting the usefulness of the mouse model to study these diseases. For these reasons, it would be advantageous to develop a technique to instill bacteria directly into the mouse lungs in order to study LRT disease in the absence of involvement of the URT. We have termed this lung specific delivery technique intubation-mediated intratracheal (IMIT) instillation. This noninvasive technique minimizes the potential for instillation into the bloodstream, which can occur during more invasive traditional surgical intratracheal infection approaches, and limits the possibility of incidental digestive tract delivery. IMIT is a two-step process in which mice are first intubated, with an intermediate step to ensure correct catheter placement into the trachea, followed by insertion of a blunt needle into the catheter to mediate direct delivery of bacteria into the lung. This approach facilitates a >98% efficacy of delivery into the lungs with excellent distribution of reagent throughout the lung. Thus, IMIT represents a novel approach to study LRT disease and therapeutic delivery directly into the lung, improving upon the ability to use mice as surrogates to study human respiratory disease. Furthermore, the accuracy and reproducibility of this delivery system also makes it amenable to Good Laboratory Practice Standards (GLPS), as well as delivery of a wide range of reagents which require high efficiency delivery to the lung.

Correlation of Klebsiella pneumoniae comparative genetic analyses with virulence profiles in a murine respiratory disease model.

Klebsiella pneumoniae is a bacterial pathogen of worldwide importance and a significant contributor to multiple disease presentations associated with both nosocomial and community acquired disease. ATCC 43816 is a well-studied K. pneumoniae strain which is capable of causing an acute respiratory disease in surrogate animal models. In this study, we performed sequencing of the ATCC 43816 genome to support future efforts characterizing genetic elements required for disease. Furthermore, we performed comparative genetic analyses to the previously sequenced genomes from NTUH-K2044 and MGH 78578 to gain an understanding of the conservation of known virulence determinants amongst the three strains. We found that ATCC 43816 and NTUH-K2044 both possess the known virulence determinant for yersiniabactin, as well as a Type 4 secretion system (T4SS), CRISPR system, and an acetonin catabolism locus, all absent from MGH 78578. While both NTUH-K2044 and MGH 78578 are clinical isolates, little is known about the disease potential of these strains in cell culture and animal models. Thus, we also performed functional analyses in the murine macrophage cell lines RAW264.7 and J774A.1 and found that MGH 78578 (K52 serotype) was internalized at higher levels than ATCC 43816 (K2) and NTUH-K2044 (K1), consistent with previous characterization of the antiphagocytic properties of K1 and K2 serotype capsules. We also examined the three K. pneumoniae strains in a novel BALB/c respiratory disease model and found that ATCC 43816 and NTUH-K2044 are highly virulent (LD50<100 CFU) while MGH 78578 is relatively avirulent.