Characterizing clinical isolates of Acanthamoeba castellanii with high resistance to polyhexamethylene biguanide in Taiwan

The article provides information about hemolytic activity, susceptibility to different groups of antibiotics and bacteriophages commercial drugs of Klebsiella pneumoniae and Pseudomonas aeruginosa clinical strains. The analysis of the obtainedresults showed a high degree of hemolytic activity dissemination among Pseudomonas aeruginosa (78,60 % of strains), as well as their high resistance to cefotaxime, chloramphenicol, azithromycin and tetracycline (82,14–100 % of resistant strains). K. pneumoniae clinical isolates were resistant to cefazolin, azithromycin, and the nitrofuran group (66,67–81,48 %). In turn, specific phagolysates for treatment deseases of K. pneumoniae and P. aeruginosa etiology showed the greatest efficiency against both groups of microorganisms among the studied commercial preparations of bacteriophages.

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Molecular Characterization of Klebsiella Pneumonia in Clinical Isolates with High Resistance toward Carbapenemases

International Journal of Clinical & Medical Microbiology ◽

10.15344/2456-4028/2018/131 ◽

2018 ◽

Vol 3 (1) ◽

Author(s):

Piero Aloisi ◽

Mattia Manelli ◽

Ramona Iseppi ◽

Carla Sabia

Keyword(s):

Molecular Characterization ◽

High Resistance ◽

Clinical Isolates ◽

Klebsiella Pneumonia

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Flow Cytometry for Determination of the Efficacy of Contact Lens Disinfecting Solutions againstAcanthamoeba spp

Applied and Environmental Microbiology ◽

10.1128/aem.66.3.1057-1061.2000 ◽

2000 ◽

Vol 66 (3) ◽

pp. 1057-1061 ◽

Cited By ~ 34

Author(s):

Roya N. Borazjani ◽

Lauren L. May ◽

Judith A. Noble ◽

Simon V. Avery ◽

Donald G. Ahearn

Keyword(s):

Methylene Blue ◽

Propidium Iodide ◽

Contact Lens ◽

Acanthamoeba Castellanii ◽

Live Cells ◽

Similar Data ◽

Flow Cytometric ◽

Polyhexamethylene Biguanide ◽

Disinfectant Solution

ABSTRACT Flow cytometric analyses of cellular staining with fluorescent viability dyes and direct microscopic observations of methylene blue exclusion were compared for evaluation of the effects of a chlorhexidine gluconate-based contact lens disinfectant solution and a polyhexamethylene biguanide solution against cysts and trophozoites ofAcanthamoeba castellanii and Acanthamoeba polyphaga. The flow cytometric procedure with propidium iodide (used to stain dead cells) indicated that more than 90% of trophozoites of both species (inocula of 105 to 106/ml) at 22°C lost their viability after 4 h of exposure to chlorhexidine. When propidium iodide was used in combination with fluorescein diacetate (for live cells), the apparent number of propidium iodide-stained cells was reduced, but the relative efficacies of the two biguanide solutions appeared unchanged from those evident with the single dyes; the chlorhexidine solution was more effective than the polyhexamethylene biguanide solution. Similar data were obtained with the more cumbersome methylene blue exclusion procedure. Flow cytometric analyses provided a statistically reproducible and rapid procedure for determining the relative antiamoebal efficacies of the disinfecting solutions.

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Cytochrome P450 monooxygenase of Acanthamoeba castellanii participates in resistance to polyhexamethylene biguanide treatment

Parasite ◽

10.1051/parasite/2021074 ◽

2021 ◽

Vol 28 ◽

pp. 77

Author(s):

Jian-Ming Huang ◽

Pin-Ju Ko ◽

Chao-Li Huang ◽

Po-Wei Wen ◽

Chun-Hsien Chen ◽

...

Keyword(s):

Cytochrome P450 ◽

Survival Rates ◽

Acanthamoeba Castellanii ◽

Serine Proteinase ◽

Cytochrome P450 Monooxygenase ◽

P450 Monooxygenase ◽

Polyhexamethylene Biguanide ◽

Granulomatous Amoebic Encephalitis ◽

Severe Infections ◽

Amoebic Keratitis

Acanthamoeba spp. are free-living parasites that can cause severe infections such as granulomatous amoebic encephalitis (GAE) and amoebic keratitis (AK). Polyhexamethylene biguanide (PHMB) is a topical application for AK treatment. However, PHMB is not entirely effective against all Acanthamoeba strains or isolates. The mechanisms by which Acanthamoeba protects itself against extreme drug conditions without encystation are still unknown. According to a previous study, cytochrome P450 monooxygenase (CYP450MO) plays an important role in the oxidative biotransformation of numerous drugs related to metabolism. In this study, a CYP450MO fragment was inserted into the pGAPDH-EGFP vector and transfected into Acanthamoeba castellanii. We found that CYP450MO-overexpressing Acanthamoeba had higher survival rates than those of the control cells after PHMB treatment. Moreover, we also found that encystation-related genes such as cellulose synthase I (CSI), encystation-mediating serine proteinase (EMSP), and autophagy-related protein 8 (ATG8) expression levels were not significantly different between Acanthamoeba transfected by pGAPDH-EGFP or pGAPDH-EGFP-CYP450MO. We suggest that Acanthamoeba transfected by pGAPDH-EGFP-CYP450MO may not induce encystation-related genes to resist PHMB treatment. In conclusion, these findings indicate that CYP450MO may be an additional target when PHMB is used for treatment of amoebic keratitis.

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High resistance to fourth-generation cephalosporins among clinical isolates of Enterobacteriaceae producing extended-spectrum β-lactamases isolated in Portugal

International Journal of Antimicrobial Agents ◽

10.1016/j.ijantimicag.2008.07.025 ◽

2009 ◽

Vol 33 (2) ◽

pp. 184-185 ◽

Cited By ~ 7

Author(s):

Ruben Fernandes ◽

Álvaro Gestoso ◽

José Mota Freitas ◽

Perpétua Santos ◽

Cristina Prudêncio

Keyword(s):

High Resistance ◽

Clinical Isolates ◽

Fourth Generation ◽

Extended Spectrum

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Phagocytosis Affects Biguanide Sensitivity of Acanthamoeba spp

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.46.7.2069-2076.2002 ◽

2002 ◽

Vol 46 (7) ◽

pp. 2069-2076 ◽

Cited By ~ 11

Author(s):

Judith A. Noble ◽

Donald G. Ahearn ◽

Simon V. Avery ◽

Sidney A. Crow

Keyword(s):

Flow Cytometry ◽

Contact Lens ◽

Acanthamoeba Castellanii ◽

Chlorhexidine Digluconate ◽

Contact Lens Wear ◽

Polyhexamethylene Biguanide ◽

Contact Lens Solutions ◽

Latex Beads ◽

Sublethal Concentrations ◽

Lens Wear

ABSTRACT The incidence of Acanthamoeba keratitis, a disease associated with contact lens wear, has been in apparent decline with the advent of multipurpose contact lens solutions. The concentrations of the biguanides chlorhexidine digluconate (CHX) and particularly polyhexamethylene biguanide (PHMB) included in multipurpose solutions (MPSs) are sublethal for amoebae. We evaluated by flow cytometry the effects of these two biguanides on phagocytosis of particles and the survival of trophozoites of Acanthamoeba castellanii and A. polyphaga. Trophozoites of A. castellanii and A. polyphaga (106/ml) were exposed to solutions of 5 and 50 μg of PHMB and CHX per ml in the presence and absence of particles (i.e., heat-killed yeasts and bacteria and latex beads). In addition, trophozoites were exposed to particles treated with these concentrations of the two biguanides. In the absence of particles, trophozoites of A. polyphaga appeared to be more resistant to the biguanides than those of A. castellanii. In the presence of particles, the rates of survival of both species were decreased. In most instances, particles treated with sublethal concentrations of both biguanides that were adsorbed onto the particles reduced the incidence of phagocytosis. Particles present in MPSs in contact lens cases may be involved in the decreased incidence of Acanthamoeba keratitis.

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Antibiotic Susceptibility Pattern of Escherichia coli Isolated from Various Clinical Samples in Duhok City, Kurdistan Region of Iraq

International Journal of Infection ◽

10.5812/iji.103740 ◽

2020 ◽

Vol 7 (3) ◽

Author(s):

Ibrahim A Naqid ◽

Amer A Balatay ◽

Nawfal Rasheed Hussein ◽

Kurdistan Abdullah Saeed ◽

Hiba Abdulaziz Ahmed ◽

...

Keyword(s):

Escherichia Coli ◽

High Resistance ◽

Antibiotic Susceptibility ◽

Bacterial Infections ◽

Antibiotic Sensitivity ◽

Multidrug Resistant ◽

Clinical Isolates ◽

Clinical Samples ◽

Sensitivity Testing ◽

E Coli

Background: Escherichia coli (E. coli) is one of the most common causative agents of bacterial infections. The emergence of multidrug-resistant E. coli is a major public health threat worldwide. Objectives: This study aimed to determine the antibiotic susceptibility profile of clinical isolates of E. coli from different samples. Methods: A total number of 454 clinical samples, including urine, wound, cervical swab, blood, semen, ascetic, and cerebral spinal fluid samples were collected from patients between January 2017 and February 2020. Then, E. coli was confirmed and susceptibility to different antibiotics was determined using the Vitek-2 compact system. Results: Escherichia coli isolates were more frequent in females (70.7%) than in males (29.3%). In the case of urine samples, E. coli was found to be highly susceptible to ertapenem (97.6%) and imipenem (96.4%) but resistant to ampicillin (87.8%). For wound and cervical swabs, E. coli was 100% resistant to ampicillin and cefepime but 100% sensitive to ertapenem and imipenem. It was found that E. coli isolates from blood samples were 100% resistant to ampicillin, ceftriaxone, and cefoxitin, and around 75% of them were sensitive to ertapenem, ciprofloxacin, and levofloxacin. Finally, E. coli isolated from other clinical samples were highly sensitive to ertapenem, imipenem, levofloxacin, nitrofurantoin, and cefazolin. Conclusions: Escherichia coli isolated from various clinical specimens showed differences in antibiotic sensitivity patterns, with high resistance to commonly used antibiotics. The most effective antibiotics against E. coli isolates were ertapenem, imipenem, and nitrofurantoin. However, the clinical isolates of E. coli displayed high resistance rates to ampicillin, ceftriaxone, and cefepime. Therefore, it is proposed to perform antibiotic sensitivity testing by physicians to select the most effective antibiotics.

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