The development of drugs against Acanthamoeba infections

For the past several decades, there has been little improvement in the morbidity and mortality associated with Acanthamoeba keratitis and Acanthamoeba encephalitis, respectively. The discovery of a plethora of antiacanthamoebic compounds has not yielded effective marketed chemotherapeutics. The rate of development of novel antiacanthamoebic chemotherapies of translational value and the lack of interest of the pharmaceutical industry in developing such chemotherapies have been disappointing. On the other hand, the market for contact lenses/contact lens disinfectants is a multi-billion-dollar industry and has been successful and profitable. A better understanding of drugs, their targets, and mechanisms of action will facilitate the development of more-effective chemotherapies. Here, we review the progress toward phenotypic drug discovery, emphasizing the shortcomings of useable therapies

Interactions of neuropathogenic Escherichia coli K1 (RS218) and its derivatives lacking genomic islands with phagocytic Acanthamoeba castellanii and nonphagocytic brain endothelial cells

Here we determined the role of various genomic islands in E. coli K1 interactions with phagocytic A. castellanii and nonphagocytic brain microvascular endothelial cells. The findings revealed that the genomic islands deletion mutants of RS218 related to toxins (peptide toxin, alpha -hemolysin), adhesins (P fimbriae, F17-like fimbriae, nonfimbrial adhesins, Hek, and hemagglutinin), protein secretion system (T1SS for hemolysin), invasins (IbeA, CNF1), metabolism (D-serine catabolism, dihydroxyacetone, glycerol, and glyoxylate metabolism) showed reduced interactions with both A. castellanii and brain microvascular endothelial cells. Interestingly, the deletion of RS218-derived genomic island 21 containing adhesins (P fimbriae, F17-like fimbriae, nonfimbrial adhesins, Hek, and hemagglutinin), protein secretion system (T1SS for hemolysin), invasins (CNF1), metabolism (D-serine catabolism) abolished E. coli K1-mediated HBMEC cytotoxicity in a CNF1-independent manner. Therefore, the characterization of these genomic islands should reveal mechanisms of evolutionary gain for E. coli K1 pathogenicity

Case report on peri-operative surgical and anaesthetic management of ruptured humongous lung abscess

Introduction: Early thoracic empyema is usually treated through video-assisted thoracoscopic (VATS) decortication. Patient selection is important for decortication if an effective surgical outcome is required. Lung isolation techniques are required to provide anesthesia for these patients to facilitate the surgeon while operating on the affected lung. The ultimate target is to protect the non-diseased contra-lateral lung from contamination.Presentation of case: We are presenting a unique case of 20-year-old female, resident of Karachi, who was brought to the emergency room (ER) with signs of sepsis, hypotension, and multi-organ failure. She was brought to the operating room to undergo video-assisted thoracoscopy (VATS) for lung abscess decortication when her medical therapy had failed. On table decision of right upper lobe resection was made and ventilation strategy had to be modified accordingly.Discussion: The main anaesthetic aim was to protect the healthy parts of the lung from the abscess. Regular suctioning of secretions during surgery via the double lumen tube (DLT) lumen on the diseased side is recommended. While performing VATS, the lung abscess got ruptured and immediate measures to isolate the lung was taken to assist with surgical resection of the affected lobe. Lobectomy can only be done once the lung was completely isolated and maintaining perfusion and ventilation of the relatively healthy lung help in managing hypoxia.Conclusion: Peri-operative management of ruptured lung abscesses required thorough pre-op evaluation, intraoperative lung isolation and ventilation, and postoperative analgesia with combined team effort both surgical and anaesthetic, are vital fundamentals to consider in guaranteeing the best outcome

Acanthamoeba castellanii of the T4 genotype is a potential environmental host for Enterobacter aerogenes and Aeromonas hydrophila

Background: Acanthamoeba can interact with a wide range of microorganisms such as viruses, algae, yeasts, protists and bacteria including Legionella pneumophila, Pseudomonas aeruginosa, Vibrio cholerae, Helicobacter pylori, Listeria monocytogenes, Mycobacterium spp., and Escherichia coli. In this capacity, Acanthamoeba has been suggested as a vector in the transmission of bacterial pathogens to the susceptible hosts.Methods: Here, we used a keratitis isolate of A. castellanii of the T4 genotype and studied its interactions with two bacterial genera which have not been tested before, Enterobacter aerogenes, and Aeromonas hydrophila, as well as E. coli. Assays were performed to determine bacterial association with and invasion of A. castellanii. Additionally, bacterial survival intracellular of A. castellanii trophozoites as well as cysts was determined.Results: All three bacterial isolates tested, associated, invaded, and survived inside A. castellanii trophozoites as well as A. castellanii cysts. However, E. aerogenes and E. coli exhibited significantly reduced association with and invasion of A. castellanii as compared with A. hydrophila (P \u3c 0.01 using paired T-test, one tail distribution). In the long term survival assays, all three bacterial isolates tested remained viable inside A. castellanii trophozoites, while amoeba remained intact; however A. hydrophila exhibited higher survival inside amoebae (14.54±3.3 bacteria:amoeba ratio) compared with E. aerogenes (3.96±0.7 bacteria:amoeba ratio) and E. coli (5.85±1.1 bacteria:amoeba ratio). A. hydrophila, E. coli, and E. aerogenes remained viable during the encystment process and exhibited higher levels of recovery from mature cysts (14.13±0.89 A. hydrophila:amoeba ratio, 10.13±1.17 E. aerogenes:amoeba ratio, and 11.95±0.7 E. coli:amoeba ratio).Conclusions: A. hydrophila and E. aerogenes also joined the ranks of other bacteria that could benefit from A. castellanii. Because cysts can be airborne, these findings suggest that Acanthamoeba is a potential vector in the transmission of A. hydrophila and E. aerogenes to susceptible hosts

Synthesis, single crystal X-ray diffraction, Hirshfeld surface and biological activity of quinolone derivatives

Two new quinolone derivatives, 5-nitroquinolin-8-yl-3-bromobenzoate (1) and 5-nitroquinolin-8-yl-3-chlorobenzoate (2), were synthesized and their structures were elucidated using X-ray diffraction techniques. Both compounds crystallized in P21/n (monoclinic) space group having four independent molecules in asymmetric unit. The dihedral angle between benzene and planner quinoline rings in compounds 1 and 2 were found to be 117.7(2) and 117.4(2)ᵒ, respectively. No intermolecular hydrogen bonding was observed in compound 1. However, C-H···O intermolecular interaction was found to connect the molecules in crystal lattice of compound 2. Hirshfeld surfaces analysis was performed to evaluate the directions, and strength of interactions of molecules of compounds and 1 and 2 with neighbouring molecules, and the major contribution in the crystal packing was due to O-H (1, 24.6% and 2, 25.1%) interactions. The synthesized quinoline derivatives were found as potent anti-bacterial agents against E. coli reference (ATCC25922 and ATCC 35218) and multi-drug resistant strains (M2 and M3) with 91.42 to 94.72% inhibition. Both compounds 1 and 2 showed weak antileishmanial activity against L. Major promastigotes in vitro with IC50 values 73.2±3.1 and 72.2±2.3 mg/mL, respectively, and also found as cytotoxic in nature against 3T3 fibroblast cell line

Gold nanoparticle conjugation enhances the antiacanthamoebic effects of chlorhexidine

Acanthamoeba keratitis is a serious infection with blinding consequences and often associated with contact lens wear. Early diagnosis, followed by aggressive topical application of drugs, is a prerequisite in successful treatment, but even then prognosis remains poor. Several drugs have shown promise, including chlorhexidine gluconate; however, host cell toxicity at physiologically relevant concentrations remains a challenge. Nanoparticles, subcolloidal structures ranging in size from 10 to 100 nm, are effective drug carriers for enhancing drug potency. The overall aim of the present study was to determine whether conjugation with gold nanoparticles enhances the antiacanthamoebic potential of chlorhexidine. Gold-conjugated chlorhexidine nanoparticles were synthesized. Briefly, gold solution was mixed with chlorhexidine and reduced by adding sodium borohydride, resulting in an intense deep red color, indicative of colloidal gold-conjugated chlorhexidine nanoparticles. The synthesis was con- firmed using UV-visible spectrophotometry that shows a plasmon resonance peak of 500 to 550 nm, indicative of gold nanoparticles. Further characterization using matrix-assisted laser desorption ionization-mass spectrometry showed a goldconjugated chlorhexidine complex at m/z 699 ranging in size from 20 to 100 nm, as determined using atomic force microscopy. To determine the amoebicidal and amoebistatic effects, amoebae were incubated with gold-conjugated chlorhexidine nanoparticles. For controls, amoebae also were incubated with gold and silver nanoparticles alone, chlorhexidine alone, neomycin-conjugated nanoparticles, and neomycin alone. The findings showed that gold-conjugated chlorhexidine nanoparticles exhibited significant amoebicidal and amoebistatic effects at 5 M. Amoebicidal effects were observed by parasite viability testing using a Trypan blue exclusion assay and flow-cytometric analysis using propidium iodide, while amoebistatic effects were observed using growth assays. In contrast, chlorhexidine alone, at a similar concentration, showed limited effects. Notably, neomycin alone or conjugated with nanoparticles did not show amoebicidal or amoebistatic effects. Pretreatment of A. castellanii with goldconjugated chlorhexidine nanoparticles reduced amoeba-mediated host cell cytotoxicity from 90% to 40% at 5 M. In contrast, chlorhexidine alone, at similar concentrations, had no protective effects for the host cells. Similarly, amoebae treated with neomycin alone or neomycin-conjugated nanoparticles showed no protective effects. Overall, these findings suggest that gold-conjugated chlorhexidine nanoparticles hold promise in the improved treatment of A. castellanii keratitis

Use of inhaled PGE1 to improve diastolic dysfunction, LVEDP, Pulmonary Hypertension and Hypoxia in ARDS—A randomised clinical trial

Introduction: We wished to see the effects of inhaled PGE1 on diastolic dysfunction, left ventricular end diastolic pressure (LVEDP), pulmonary hypertension and hypoxia in ARDS patients. Methods: This is a randomized, prospective, clinical trial conducted in the main adult intensive care unit of a tertiary care University hospital. A total of 67 patients were recruited. Inclusion criteria included all adult patients with a P/F ratio /or Pulmonary Artery systolic (Pa) pressures of \u3e35 mmHg on Pulmonary artery catheter or suspected on clinical grounds. A transthoracic echo was performed to record the diastolic function, LVEDP and Pa pressures. Subsequently patients were randomized by a block computerized randomization to either cases (n = 34) or controls (n = 33). Cases received nebulised PGE1 over 30 minutes in the ICU and normal saline was administered to controls blindly. Following this the echo and arterial blood gases were repeated. Our primary outcomes were an improvement in diastolic function and P/F ratio of greater than 20% and a decrease in pulmonary pressure and LVEDP of \u3e20%. Results: At baseline, mean diastolic dysfunction was grade II, with a mean LVEDP of \u3e15 and the PaO2/FiO2 ratio was 148.38 ± 60.05 with a mean pulmonary artery pressure of 81.35 ± 16.91. Inhaled PGE1 was followed by an improvement in diastolic dysfunction (grade I, p = 0.001) with a resulting improvement in LVEDP (12 +/? 2, p = 0.001) as well as Pa pressures (97.09 ± 30.06, p = 0.04) and a non significant improvement in PaO2/FiO2 ratio (161.45 ± 77.52, p = 0.21). There were no side effects observed in any patients. Conclusion: Our study shows that there is a significant improvement in diastolic dysfunction, LVEDP and Pa pressures after administration of nebulised PGE1, and an improvement although non-significant in hypoxia in ARDS patients. The trial was registered with Clinicaltrials.gov (NCT00314548) and funded by the Pakistan medical research council

Factors influencing the use of postoperative bilevel positive airway pressure (BiPAP) in patients undergoing adult cardiac surgery: A retrospective cohort study

Background and aims: Respiratory complications are one of the biggest challenges following cardiac surgery, which can lead to hypoxia and acute respiratory failure (ARF). The aim of this study to identify the factors led to BiPAP application for postoperative respiratory complications and its effectiveness as the main outcome measures after cardiac surgery.Methods: It was a retrospective cohort study with consecutive sampling technique. A total of 335 postcardiac surgery patients medical record was reviewed who were underwent for surgery from November 1, 2018 to November 30, 2019. 265 patients were finalized for the recruitment, five patients were excluded before the final analysis. Data of 260 patients were analyzed for compiling of results.Results: The mean age was 59 years. 196 (75.4%) patients were males and females were 64 (24.6%). Mean weight was 72 kg and mean body mass index (BMI) 26.67 kg/m2 . BiPAP application was in 38 (14.6%) patients and significantly high in with high BMI, (p \u3c 0.05). There are significant associations of BiPAP application patients with COPD (p \u3c 0.05). Patients with positive fluid balance, cardiac dysfunction, and required inotropic support were significantly associated with BiPAP need (p \u3c 0.05), respectively.Conclusion: BiPAP is effective to treat ARF and other respiratory complications after adult cardiac surgeries. High BMI, atelectasis, and pneumonia are also the independent factors causing ARF. BiPAP can be a successful tool for preventing the adverse effects of postoperative pulmonary complications after cardiac surgery