Exploring reduced macrophage cell toxicity of hypervirulent Klebsiella pneumoniae compared to classical Klebsiella pneumoniae

Bacterial pneumoniae caused by Klebsiella pneumoniae (Kp) is a major concern due to the prevalence of multiple antibiotic-resistant strains, which limit treatment options and increase mortality rates. Patients with Kp infections often experience an uncontrolled immune response in the lungs, leading to excessive inflammation and elevated levels of proinflammatory cytokines. This study aimed to investigate the cytotoxicity, the inflammatory cytokine response, and the longevity of intracellular bacterial load in RAW 264.7 macrophages, infected with two different Kp strains - cKP (HKU1: Classical Kp) and HvKP (17ZR101: Hypervirulent Kp). This study found that after infecting macrophages with cKP and HvKP, the internalization rate was faster and the intracellular cKP load was higher than that of HvKP. Additionally, the number of intracellular Kp was correlated with the presence of M1 macrophage polarization marker CD86 and expressions of proinflammatory cytokines. Interestingly, the expression of these proinflammatory cytokines was significantly higher in cKP-infected macrophages than in HvKP-infected macrophages. Thus, a higher intracellular cKP load is suggested to play a significant role in causing more proinflammatory cytokines and killing macrophages compared to HvKP infection. This finding highlights the importance of understanding the mechanisms behind Kp infections and developing effective treatment strategies.

Occurrence of shigellosis in pediatric diarrheal patients in Chattogram, Bangladesh: A molecular based approach

Shigellaa Gram-negative, non-motile bacillus, is the primary causative agent of the infectious disease shigellosis, which kills 1.1 million people worldwideevery year. The children under the age of five are primarily the victims of this disease. This study has been conducted to assess the prevalence of shigellosis through selective plating, biochemical test and conventional PCR assays, where the samples were collected from suspected diarrheoal patients. Invasive plasmid antigen H (ipaH) and O-antigenic rfc gene were used to identify Shigella spp. and S. flexneri respectively. For validation of these identification, PCR product of ipaH gene of a sample (Shigella flexneri MZS 191) has been sequenced and submitted to NCBI database (GenBank accession no- MW774908.1). Further this strain has been used as positive control. Out of 204, around 14.2% (n = 29)(P> 0.01) pediatric diarrheoal cases were screened as shigellosis. Another interesting finding was that most of shigellosis affected children were 7 months to 1 year (P> 0.01).The significance of this study lies in the analyses of the occurrenceand the molecular identification of Shigellaspp. and S. flexneri that can be utilized in improving the accurate identification and the treatment of the most severe and alarming shigellosis.

The Prevalence of Multi-Drug Resistant Salmonella typhi Isolated From Blood Sample

Typhoid is a major public health concern. Even though antibiotics are usually used to treat typhoid fever, the spread of multi drug resistant Salmonella typhi is making antibiotics much less effective. This study was conducted to assess the prevalence of multidrug-resistant Salmonella typhi from the clinical samples. During this study, 154 blood samples of suspected typhoid patients were collected from the hospital and diagnostic center located in Chattogram City, Bangladesh. Isolation and identification of Salmonella typhi was done by both biochemical tests. PCR analysis was also done for the confirmation of biochemical result. Antimicrobial susceptibility test was performed according to the Kirby-Bauer disk diffusion method against ampicillin, chloramphenicol, cefepime, cotrimoxazole, ceptriaxone, ciprofloxacin, nalidixic acid, and azithtomycin. Out of 154, 21 (13.64%) isolates were identified as Salmonella typhi and the prevalence of typhoid in Chattogram, Bangladesh was 13.64% (n = 21). It was also found that children under the age of 5 are the more vulnerable target of Salmonella typhi infection. Antibiotic resistance profiling revealed 85% isolates were Multi-Drug Resistant (MDR) and highest resistance was found in case of Nalidixic acid. Although, most of the isolated Salmonella typhi were MDR, first generation antibiotics Co-trimoxazile, Chloramphenicol, and Ampicillin were found effective against Salmonella typhi.

Antibiotic Resistance and Plasmid Profiling of Escherichia coli Isolated from Human Sewage Samples

In developing countries, the occurrence of antibiotic resistance is increasing day by day and antibiotic resistant microorganisms are being found in almost every environmental setting. Plasmids are considered as the main vector in the procurement and propagation of antibiotic resistance in many microorganisms such as Escherichia coli (E. coli). The goal of this study was to examine the antibiotic resistance and screening of plasmid in E. coli strains which were previously identified from human sewage samples. During this study antibiotic susceptibility of E. coli isolates were determined by Kirby-Bauer disk diffusion method against 5 antibiotics (ampicilin, ceftriaxone, amoxicillin, ciprofloxacin, azithromycin). Furthermore, plasmid extraction of each isolate was done according to the protocol of FavorPrepTMPlasmid Mini Kit and plasmid profiling was done by agarose gel electrophoresis. In antibiotic sensitivity test, all E. coli strains showed resistance to ampicilin, amoxicillin, and ceftriaxone. In the plasmid profiling, it was revealed that all the isolates of E. coli harbored plasmids. The plasmid sizes ranged from approximately 1.5 to 15 kb. The findings of this study prove the consequences of antibiotic resistance as well as relationship of plasmid with antibiotic resistance which necessitates proper surveillance on antibiotic usage in the developing countries.

Influence of foliar spray of ethephon and water stress on the essential oil composition and impact on the cytotoxic activity of Thymus vulgaris aerial parts

Thymus vulgaris, (Lamiaceae), essential oils composition and yield, were found to be greatly influenced by water stress and growth enhancers. Therefore, three controlled cultivation conditions were applied to achieve the highest essential oil productivity of T. vulgaris. The essential oils obtained by hydro-distillation of the aerial parts were analyzed using (GC-MS). The tested plant subjected to drought showed a 66% increase in the essential oil yield, while those subjected to drought stress and foliar spray showed 57.1% increase and the regularly irrigated group with foliar spraying showed 23.8% increase relative to the control group. The cytotoxic activity of T. vulgaris essential oils was evaluated against lung (A-549), colon (HCT-116), intestinal (CACO₂) and breast (MCF-7) carcinoma using the cell viability assay. The lowest IC₅₀ values 0.44 and 0.33 μg/mL were seen against (HCT-116) and (CACO₂) cells respectively. These IC₅₀ values were lower than that of doxorubicin used as reference drug.

Characterization of furnace oil bioremediation potential of hydrocarbonoclastic bacteria isolated from petroleum contaminated sites of the Sundarbans, Bangladesh

Spillage of furnace oil is a more frequent event in recent times. In this study, environmental samples from furnace oil spillage sites of the Shela River, the Sundarbans, Bangladesh, were collected after three weeks of spillage. Serial dilution was applied and total seven bacterial isolates were separated as pure cultures. The oil-degrading potentiality of all seven isolates was further assessed, confirmed and compared with the growth pattern in furnace oil supplemented media, 2, 6-dichlorophenolindophenol test, and gravimetric analysis. After 7 days of incubation, isolates SS3, RW2, and SB degraded 56%, 43%, and 52% of supplemented furnace oil, respectively. The top three hydrocarbonoclastic bacterial isolates were selected as potential and identified as Pseudomonas aeruginosa (SS3), Bacillus sp. (RW2), and Serratia sp. (SB). All three isolates showed significant oil-degrading capacity compared to negative control, when incubated in sterile pond water supplemented with 2% furnace oil, suggesting them as potential bioremediation agents.

Saponins and acylated saponins from Dizygotheca kerchoveana

Four new triterpenoid saponins were isolated from the leaves and stem of branches of Dizygotheca kerchoveana along with seven known ones. The new saponins were respectively characterized as 3-O-[beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid, 3-O-[beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-[beta-D-3-O-trans-p-coumaroyl-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester and 3-O-[beta-d-3-O-cis-p-coumaroyl-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester. Their structures were elucidated by 1D and 2D NMR experiments, FAB-MS as well as chemical means.

New steroidal saponins from Agave lophantha Schiede and their pharmacological evaluation

The structures of one new monodesmosidic spirostanoside and one new bisdesmosidic furanostanol glycoside isolated from leaves of Agave lophantha Schiede have been determined by means of spectroscopic and chemical methods as (25R)-5 beta-spirostan-3 beta-ol-3-O-(beta-D-apiofuranosyl(1-->4)beta-D -glucopyranosyl(1-->3)[beta-D-glucopyranosyl(1-->2)]beta-D -galactopyranoside) and 26-O-beta-D-glucopyranosyl(25R)-5 beta-furost-20(22)-ene-3 beta, 26-diol-3-O-(beta-D-xylopyranosyl(1-->3)-[beta-D-glucopyranosyl(1--2)] beta-D-galactopyranoside), respectively. The 1H and 13C NMR resonances of the two compounds were assigned by NMR (1H, 13C, HOHAHA, 1H-1H COSY, HMQC, HMBC, NOE difference) studies. The pharmacological activities of the saponin containing fraction are discussed.