Antibacterial Activity and Phytochemical Screening of Erythrina fusca Lour. Leaf Extract (Fabaceae)

Erythrina fusca Lour. (family Fabaceae) is a flowering tree that is locally known as ‘chengkering’. The plant is traditionally used in treatment of some symptoms related to bacterial infections such as wound infections, inflammations, and skin itching. This work reports for the first time in vitro antibacterial screening of the E. fusca Lour. methanolic leaf extract against some common Gram-negative and Gram-positive bacteria such as Klebsiella pneumonia, Proteus vulgaris, Pseudomonas aeruginosa, Bacillus cereus, Bacillus subtilis, and Staphylococcus aureus. The in vitro antibacterial assay was carried out using agar diffusion method with the extract concentration of 3 mg/well and vancomycin 30 µg/well as the positive control. It was found that the extract exhibits antibacterial effects in range of 10.5 – 14 mm of zone of inhibition (ZOI) against all tested bacteria except for K. pneumoniae. P. aeruginosa showing ZOI of 14 mm was the most sensitive bacterium while P. vulgaris (ZOI of 10.5 mm) was the least sensitive strain to the extract. Based on the preliminary phytochemical screening of using standard qualitative phytochemical tests, this species contains significant amount of alkaloids, flavonoids, terpenoids, and tannins, which might contribute to the antibacterial activity of the extract. Both antibacterial potential and presence of various phytochemicals in the extract could support the traditional uses of E. fusca , and the obtained results would serve as a basis for further exploration of antibacterial properties of the plant’s leaves.

Detection of Nocardia by 16S Ribosomal RNA Gene PCR and Metagenomic Next-Generation Sequencing (mNGS)

In this study, the aim was to investigate the discriminatory power of molecular diagnostics based on mNGS and traditional 16S ribosomal RNA PCR among Nocardia species. A total of fourteen clinical isolates from patients with positive Nocardia cultures and clinical evidence were included between January 2017 and June 2020 in HeNan Provincial People’s Hospital. DNA extraction and 16S rRNA PCR were performed on positive cultures, and pathogens were detected by mNGS in these same samples directly. Among the 14 Nocardia isolates, four species were identified, and N. cyriacigeorgica (8 cases) is the most common species. Twelve of the 14 Nocardia spp. isolates were identified by the two methods, while two strains of N. cyriacigeorgica were not identified by mNGS. All tested isolates showed susceptibility to trimethoprim-sulfamethoxazole (SXT), amikacin and linezolid. Apart from Nocardia species, other pathogens such as Acinetobacter baumannii, Klebsiella pneumonia, Aspergillus, Enterococcus faecalis, Human herpesvirus, etc., were detected from the same clinical samples by mNGS. However, these different pathogens were considered as colonization or contamination. We found that it is essential to accurately identify species for determining antibiotic sensitivity and, consequently, choosing antibiotic treatment. 16S rRNA PCR was useful for identification of nocardial infection among species, while this technique needs the clinicians to make the pre-considerations of nocardiosis. However, mNGS may be a putative tool for rapid and accurate detection and identification of Nocardia, beneficial for applications of antimicrobial drugs and timely adjustments of medication.

Gentamicin-Montmorillonite Intercalation Compounds as an Active Component of Hydroxypropylmethylcellulose Bionanocomposite Films with Antimicrobial Properties

The present study introduces an overview of gentamicin-clay mineral systems for applications in biomedicine and then focuses on the development of a series of gentamicin/clay hybrid materials to be used as the bioactive phase of hydroxypropylmethylcellulose (HPMC) to produce bionanocomposite membranes possessing antimicrobial activity of interest in wound-dressing applications. Gentamicin (Gt) was adsorbed from aqueous solutions into a montmorillonite (Cloisite®-Na+) to produce intercalation compounds with tunable content of the antibiotic. The hybrids were characterized by CHN chemical analysis, energy-dispersive X-ray analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis, confirming the intercalation of Gt by an ion-exchange mechanism. The release of Gt from the hybrids was tested in water and in buffer solution to check their stability. Hybrids with various amounts of Gt were incorporated into a HPMC matrix at various loadings and processed as films by the casting method. The resulting Gt-clay/HPMC bionanocomposites were characterized by means of field-emission scanning electron microscopy, and were also evaluated for their water-adsorption and mechanical properties to confirm their suitability for wound-dressing applications. The antimicrobial activity of the bionanocomposite films was tested in vitro toward various microorganisms (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium, Acinetobacter baumannii, and Klebsiella pneumonia), showing a complete bacterial reduction even in films with small Gt contents.

ANTIBACTERIAL ACTIVITY OF CHLOROGENIC ACID PHYTOVESICLES AGAINST RESISTANT BACTERIA: DEVELOPMENT, OPTIMIZATION AND EVALUATION

Objective: To investigate the in vitro antibacterial activity of a naturally occurring polyphenol chlorogenic acid (CGA) and compares it with formulated chlorogenic acid phytovesicles against 4 different bacterial strains; two gram positive [Staphylococcous aureus and Bacillus subtilis] and two gram negative strains [Klebsiella pneumonia and Escherichia coli]. Methods: CGA phytovesicles were developed and optimized using central composite design to improvise CGA’s physicochemical properties. Bactericidal activity was evaluated using agar diffusion, minimum inhibitory concentration (MIC) and time kill assay. The effect of pH and temperature on the antimicrobial activity was determined. Results: The optimized CGA phytovesicles showed entrapment of 96.89% with 30 times better lipophilic solubility than the plain drug. The inhibition zone sizes for CGA phytovesicle ranged from 17-25 mm as compared to 15-20 mm of plain CGA while the MIC values ranged 200-250 µg/ml as compared to 500-550 µg/ml of plain CGA. CGA phytovesicles exhibited a strong bactericidal effect at MIC with a log reduction in the range of 0.90-2.04 in Colony forming units (CFUs) at 24h for different strains as compared to 1.38-2.17 of plain CGA. Furthermore, the antibacterial effect was found to augment with increasing temperature but decreased with alkaline pH. Conclusion: Results strongly supports the hypothesis of potential use of CGA phytovesicles as a mode of drug delivery for its antibacterial use against different resistant bacteria.

Urethral Discharge as A Novel Manifestation of Urinary Tract Infection in Children ≤24 Months Old

Background: Children with urinary tract infections (UTIs) are prone to kidney scarring if they are not treated promptly; however, ambiguous symptoms before fever onset makes the early detection of UTIs difficult. Our study aimed to identify urethral discharge as an early manifestation in children with UTI. Methods: This study enrolled 678 children younger than 24 months with paired urinalysis and culture performed between 2015 and 2021; 544 children were diagnosed with UTIs. Clinical symptoms, urinalysis, and paired urine culture results were compared. Results: Urethral discharge was observed in 5.1% of children with UTI and yielded a specificity of 92.5% for diagnosing UTI. Children with urethral discharge had a less severe UTI course, furthermore, nine of them received antibiotics before fever occurred and seven of them were free of fever during UTI course. Urethral discharge was associated with alkalotic urine and Klebsiella pneumonia infection.Conclusions: Urethral discharge is an early symptom in children with UTI; it may present before fever onset and help ensure prompt antibiotic intervention.Trial registration: Not applicable.

Isolation and Identification of major bacteria from three Ethiopian rift valley lakes live and processed fish, and water samples: Implications in sanitary system of fish products

Bacterial pathogens are a great threat to fish production. Gram-negative bacteria are among the major bacterial fish pathogens and zoonotic with the potential to infect humans. This cross-sectional study was conducted to isolate and identify major gram-negative bacteria from live and processed fish, and water samples from Lakes Hawassa, Langanoo and Ziway. A total of 674 different types of samples: 630 tissue samples (210 samples for each intestine, Kidney and liver collected from 210 live fish (Oreochromis niloticus, Cyprinus carpio and Clarias gariepinus), 20 processed fish samples from lake Ziway fish processing center and 24 lake water samples were included in the study from each lake. The mean values of pH, temperature, dissolved oxygen and nitrate in all water samples were within the normal range at which most freshwater fish species become non-stressed. Of a total of 674 samples included in the study, the bacteria were isolated from 154 (22.8%) samples with significant difference (P<0.05) observed in some isolates with respect to sample origin. Of these 154 isolates, 103(66.8%) isolates were gram-negative bacteria consisting of 15 species based on morphology and a range of biochemical tests. From live fish samples, Escherichia coli was the dominant species with 15 isolates followed by Edwardsiella tarda (12), Salmonella Paratyphi (10), Salmonella Typhi (9), Shigella dysenteriae(7), Shigella flexneri (7), Klebsiella pneumonia (7), Enterobacter aerogenes (6), Enterobacter cloacae (5), Pseudomonas aeruginosa (5), Vibrio parahemolyticus (5), Aeromonas sobria (4), Citrobacter freundii (4), Citrobacter koseri (4) and Plesiomonas shigelloides(3). Detection of common fecal coliforms (E. coli, K. pneumoniae and E. aerogenes) and Salmonella spp. in processed fish indicates the potential danger of passage of pathogenic bacteria and/or their poisons to humans via infected and/or contaminated fish products. Human infection by pathogenic fish bacteria and food poisoning is possible through contamination of fish product in fish production chain due to inadequate handling, poor hygiene and contact with contaminated water. Therefore, producers, consumers and all other stakeholders need to be cautious during handling, processing and consumption of fish harvested from the study lakes.

ISOLATION AND IDENTIFICATION OF MICROBIAL FAUNA IN UTI PATIENTS

Urinary tract infection caused by bacteria leads to inflammation. It is an important infection which can cause a highly morbidity rates in both males and females. The aim of the present study was determine the percentage prevalence of the UTI among the general population and the percentage of the bacterial isolates in the Urine samples. Among 150 samples bacterial isolates were obtained which included Escherichia coli, Klebsiella pneumonia, Proteus vulgaris, Pseudomonas aeruginosa. The highest prevalence of specific bacteria was found to be Escherichia coli recorded among all the UTI patients to be (55.55%) the least percentage among the bacteria were Klebsiella pneumonia, Proteus vulgaris, Pseudomonas aeruginosa and Enterobacter aerogenes which recorded 16.66%, 5.55%, 11.11% and 11.11% respectively. Results of the study showed that of femaleshad UTI more than the males.