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Microbiology Spectrum Jun 2024Bacteria are involved in numerous interactions during infection and among host-associated microbial populations. serovar Typhimurium is a foodborne pathogen of great...
Bacteria are involved in numerous interactions during infection and among host-associated microbial populations. serovar Typhimurium is a foodborne pathogen of great importance as well as a model organism to study interactions within a microbial community. In this study, we found that . Typhimurium becomes tolerant to azithromycin when co-cultured with lactobacilli strains. Similarly, acidified media, from cell-free supernatant of lactobacilli cultures for instance, also induced the tolerance of . Typhimurium to azithromycin. The addition of membrane disruptors restored the normal sensitivity to azithromycin in acidified media, but not when lactobacilli were present. These results suggested that the acidification of the media led to modification in envelope homeostasis, but that a different mechanism promoted the tolerance to azithromycin in the presence of lactobacilli strains. To further understand how lactobacilli strains modify the sensitivity of . Typhimurium to azithromycin, a high-throughput assay was performed using the single-gene deletion collection of the . Typhimurium (1) in co-culture with and (2) in sterile acidic conditions (pH 5.5 media only). As expected, both screens identified genes involved in envelope homeostasis and membrane permeability. Our results also suggest that changes in the metabolism of . Typhimurium induce the tolerance observed in the presence of . Our results thus highlight two different mechanisms by which lactobacilli induce the tolerance of . Typhimurium to azithromycin.IMPORTANCEThis study provides valuable insights into the intricate interactions between bacteria during infections and within host-associated microbial communities. Specifically, it sheds light on the significant role of lactobacilli in inducing antibiotic tolerance in serovar Typhimurium, a critical foodborne pathogen and model organism for microbial community studies. The findings not only uncover the mechanisms underlying this antibiotic tolerance but also reveal two distinct pathways through which strains of lactobacilli might influence 's response to antibiotics. Understanding these mechanisms has the potential to enhance our knowledge of bacterial infections and may have implications for the development of strategies to combat antibiotic resistance in pathogens, such as . Furthermore, our results underscore the necessity to explore beyond the direct antimicrobial effects of antibiotics, emphasizing the broader microbial community context.
PubMed: 38916329
DOI: 10.1128/spectrum.03497-23 -
PLoS Neglected Tropical Diseases May 2024In Brazil, Leishmania amazonensis is the etiological agent of cutaneous and diffuse cutaneous leishmaniasis. The state of Maranhão in the Northeast of Brazil is...
In Brazil, Leishmania amazonensis is the etiological agent of cutaneous and diffuse cutaneous leishmaniasis. The state of Maranhão in the Northeast of Brazil is prevalent for these clinical forms of the disease and also has high rates of HIV infection. Here, we characterized the drug susceptibility of a L. amazonensis clinical isolate from a 46-year-old man with diffuse cutaneous leishmaniasis coinfected with HIV from this endemic area. This patient underwent several therapeutic regimens with meglumine antimoniate, liposomal amphotericin B, and pentamidine, without success. In vitro susceptibility assays against promastigotes and intracellular amastigotes demonstrated that this isolate had low susceptibility to amphotericin B, when compared with the reference strain of this species that is considered susceptible to antileishmanial drugs. Additionally, we investigated whether the low in vitro susceptibility would affect the in vivo response to amphotericin B treatment. The drug was effective in reducing the lesion size and parasite burden in mice infected with the reference strain, whereas those infected with the clinical isolate and a resistant line (generated experimentally by stepwise selection) were refractory to amphotericin B treatment. To evaluate whether the isolate was intrinsically resistant to amphotericin B in animals, infected mice were treated with other drugs that had not been used in the treatment of the patient (miltefosine, paromomycin, and a combination of both). Our findings demonstrated that all drug schemes were able to reduce lesion size and parasite burden in animals infected with the clinical isolate, confirming the amphotericin B-resistance phenotype. These findings indicate that the treatment failure observed in the patient may be associated with amphotericin B resistance, and demonstrate the potential emergence of amphotericin B-resistant L. amazonensis isolates in an area of Brazil endemic for cutaneous leishmaniasis.
Topics: Amphotericin B; Animals; Brazil; Middle Aged; Antiprotozoal Agents; Humans; Male; Mice; Drug Resistance; Leishmania; Leishmania mexicana; Leishmaniasis, Cutaneous; HIV Infections; Parasitic Sensitivity Tests; Mice, Inbred BALB C; Leishmaniasis, Diffuse Cutaneous
PubMed: 38768213
DOI: 10.1371/journal.pntd.0012175 -
Transplantation Proceedings May 2024Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that, in immunocompromised patients, can progress to respiratory failure and death. Since...
Pneumocystis jirovecii Pneumonia in a Liver Transplant Recipient With an Adverse Reaction to Trimethoprim/Sulfamethoxazole Treated With a Sulfonamide Desensitization Protocol: Case Report.
BACKGROUND
Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that, in immunocompromised patients, can progress to respiratory failure and death. Since trimethoprim/sulfamethoxazole (TMP/SMX) chemoprophylaxis has become a standard management, the prognosis has improved. However, there are patients with a history of TMP/SMX intolerance who cannot receive chemoprophylaxis.
BACKGROUND
We report on a 53-year-old male liver recipient treated with a standard triple immunosuppressive regimen in whom TMP/SMX was waived because of a history of allergy manifested as a generalized rash with edema more than 30 years ago. At transplantation, the immunologic risk was assessed as low, and liver graft function was normal. In the third month after engraftment, he developed dyspnea at rest required constant passive oxygen therapy. Ceftriaxone, azithromycin, and clindamycin were implemented. Mycophenolate acid was stopped, and tacrolimus was reduced. High-resolution computed tomography revealed interstitial pneumonia. Pneumocystis jirovecii pneumoniae was diagnosed from bronchoalveolar lavage. Instead of TMP/SMX, pentamidine and caspofungin were also used for PJP, with no improvement. After 3 weeks, the patient deteriorated. Because of his life-threatening condition, TMP/SMX was introduced in the sulfonamide desensitization protocol, including hydrocortisone and clemastinum. Within 4 days, the patient stabilized with no signs of TMP/SMX intolerance. Pneumonia subsided within a month, and TMP/SMX was prescribed lifelong.
CONCLUSIONS
Prophylaxis for PJP with TMP/SMX still remains an important issue in transplant recipients. Adverse reaction to TMP/SMX in the past is not always a contraindication to reintroducing prophylaxis. The decision of prophylaxis avoidance should be analyzed carefully; in uncertain cases, a sulfonamide desensitization protocol should be considered.
Topics: Humans; Male; Middle Aged; Pneumonia, Pneumocystis; Trimethoprim, Sulfamethoxazole Drug Combination; Liver Transplantation; Pneumocystis carinii; Sulfonamides; Desensitization, Immunologic; Immunocompromised Host; Immunosuppressive Agents
PubMed: 38760300
DOI: 10.1016/j.transproceed.2024.03.022 -
Nature Communications May 2024Pentamidine and melarsoprol are primary drugs used to treat the lethal human sleeping sickness caused by the parasite Trypanosoma brucei. Cross-resistance to these two...
Pentamidine and melarsoprol are primary drugs used to treat the lethal human sleeping sickness caused by the parasite Trypanosoma brucei. Cross-resistance to these two drugs has recently been linked to aquaglyceroporin 2 of the trypanosome (TbAQP2). TbAQP2 is the first member of the aquaporin family described as capable of drug transport; however, the underlying mechanism remains unclear. Here, we present cryo-electron microscopy structures of TbAQP2 bound to pentamidine or melarsoprol. Our structural studies, together with the molecular dynamic simulations, reveal the mechanisms shaping substrate specificity and drug permeation. Multiple amino acids in TbAQP2, near the extracellular entrance and inside the pore, create an expanded conducting tunnel, sterically and energetically allowing the permeation of pentamidine and melarsoprol. Our study elucidates the mechanism of drug transport by TbAQP2, providing valuable insights to inform the design of drugs against trypanosomiasis.
Topics: Trypanosoma brucei brucei; Aquaglyceroporins; Cryoelectron Microscopy; Molecular Dynamics Simulation; Melarsoprol; Pentamidine; Biological Transport; Trypanocidal Agents; Protozoan Proteins; Humans
PubMed: 38734677
DOI: 10.1038/s41467-024-48445-4 -
Drug Delivery and Translational Research May 2024Biodegradable nanocarriers possess enormous potential for use as drug delivery systems that can accomplish controlled and targeted drug release, and a wide range of...
Biodegradable nanocarriers possess enormous potential for use as drug delivery systems that can accomplish controlled and targeted drug release, and a wide range of nanosystems have been reported for the treatment and/or diagnosis of various diseases and disorders. Of the various nanocarriers currently available, liposomes and polymer nanoparticles have been extensively studied and some formulations have already reached the market. However, a combination of properties to create a single hybrid system can give these carriers significant advantages, such as improvement in encapsulation efficacy, higher stability, and active targeting towards specific cells or tissues, over lipid or polymer-based platforms. To this aim, this work presents the formulation of poly(lactic-co-glycolic) acid (PLGA) nanoparticles in the presence of a hyaluronic acid (HA)-phospholipid conjugate (HA-DPPE), which was used to anchor HA onto the nanoparticle surface and therefore create an actively targeted hybrid nanosystem. Furthermore, ionic interactions have been proposed for drug encapsulation, leading us to select the free base form of pentamidine (PTM-B) as the model drug. We herein report the preparation of hybrid nanocarriers that were loaded via ion-pairing between the negatively charged PLGA and HA and the positively charged PTM-B, demonstrating an improved loading capacity compared to PLGA-based nanoparticles. The nanocarriers displayed a size of below 150 nm, a negative zeta potential of -35 mV, a core-shell internal arrangement and high encapsulation efficiency (90%). Finally, the ability to be taken up and exert preferential and receptor-mediated cytotoxicity on cancer cells that overexpress the HA specific receptor (CD44) has been evaluated. Competition assays supported the hypothesis that PLGA/HA-DPPE nanoparticles deliver their cargo within cells in a CD44-dependent manner.
PubMed: 38709442
DOI: 10.1007/s13346-024-01617-7 -
Journal of Voice : Official Journal of... Apr 2024Leishmaniasis represents an emerging public health issue in Mediterranean countries. The incidence of this condition has progressively risen in Northern Italy due to the...
Leishmaniasis represents an emerging public health issue in Mediterranean countries. The incidence of this condition has progressively risen in Northern Italy due to the growing number of immunocompromised people and probably due to climate changes. We hereby describe a case of relapsing laryngeal leishmaniasis in a female immunocompetent patient, presenting as aspecific chronic laryngitis. She was affected by severe asthma treated by inhaled steroid therapy, likely responsible for the parasite's diffusion through a locus minori resistentiae. The aspecific clinical presentation led to a delayed diagnosis and the lack of guidelines for the treatment caused multiple relapses. Biopsies of laryngeal lesions in the follow-up were performed by operative flexible videolaryngoscopy, thus avoiding general anesthesia and reducing associated healthcare costs. The aim of this report is to underline the diagnostic and therapeutic challenges that patients with this condition face and to present what is, to the best of our knowledge, the first application of prophylactic aerosolized pentamidine for relapsing laryngeal leishmaniasis.
PubMed: 38658203
DOI: 10.1016/j.jvoice.2024.04.006 -
Frontiers in Aging Neuroscience 2024The efficacy of current treatments is still insufficient for Alzheimer's disease (AD), the most common cause of Dementia. Out of the two pathological hallmarks of AD...
The efficacy of current treatments is still insufficient for Alzheimer's disease (AD), the most common cause of Dementia. Out of the two pathological hallmarks of AD amyloid-β plaques and neurofibrillary tangles, comprising of tau protein, tau pathology strongly correlates with the symptoms of AD. Previously, screening for inhibitors of tau aggregation that target recombinant tau aggregates have been attempted. Since a recent cryo-EM analysis revealed distinct differences in the folding patterns of heparin-induced recombinant tau filaments and AD tau filaments, this study focused on AD seed-dependent tau aggregation in drug repositioning for AD. We screened 763 compounds from an FDA-approved drug library using an AD seed-induced tau aggregation in SH-SY5Y cell-based assay. In the first screening, 180 compounds were selected, 72 of which were excluded based on the results of lactate dehydrogenase assay. In the third screening with evaluations of soluble and insoluble tau, 38 compounds were selected. In the fourth screening with 3 different AD seeds, 4 compounds, lansoprazole, calcipotriene, desogestrel, and pentamidine isethionate, were selected. After AD seed-induced real-time quaking-induced conversion, lansoprazole was selected as the most suitable drug for repositioning. The intranasal administration of lansoprazole for 4 months to AD seed-injected mice improved locomotor activity and reduced both the amount of insoluble tau and the extent of phosphorylated tau-positive areas. Alanine replacement of the predicted binding site to an AD filament indicated the involvement of Q351, H362, and K369 in lansoprazole and C-shaped tau filaments. These results suggest the potential of lansoprazole as a candidate for drug repositioning to an inhibitor of tau aggregate formation in AD.
PubMed: 38633982
DOI: 10.3389/fnagi.2024.1368291 -
International Journal of Infectious... Jun 2024In hematology, prophylaxis for Pneumocystis jirovecii pneumonia (PCP) is recommended for patients undergoing hematopoietic stem cell transplantation and in selected...
A retrospective study of intravenous pentamidine for Pneumocystis jirovecii pneumonia prophylaxis in adult patients with hematologic malignancies-its utility during respiratory virus pandemics.
OBJECTIVES
In hematology, prophylaxis for Pneumocystis jirovecii pneumonia (PCP) is recommended for patients undergoing hematopoietic stem cell transplantation and in selected categories of intensive chemotherapy for hematologic malignancies. Trimethoprim-sulfamethoxazole (TMP-SMX) is the recommended first-line agent; however, its use is not straightforward. Inhaled pentamidine is the recommended second-line agent; however, aerosolized medications were discouraged during respiratory virus outbreaks, especially during the COVID-19 pandemic, in view of potential contamination risks. Intravenous (IV) pentamidine is a potential alternative agent. We evaluated the effectiveness and tolerability of IV pentamidine use for PCP prophylaxis in adult allogeneic hematopoietic stem cell transplantation recipients and patients with hematologic malignancies during COVID-19.
RESULTS
A total of 202 unique patients who received 239 courses of IV pentamidine, with a median of three doses received (1-29). The largest group of the patients (49.5%) who received IV pentamidine were undergoing or had received a hematopoietic stem cell transplant. The most common reason for not using TMP-SMX prophylaxis was cytopenia (34.7%). We have no patients who had breakthrough PCP infection while on IV pentamidine. None of the patients developed an infusion reaction or experienced adverse effects from IV pentamidine.
CONCLUSIONS
Pentamidine administered IV monthly is safe and effective.
Topics: Humans; Pentamidine; Pneumonia, Pneumocystis; Hematologic Neoplasms; Male; Retrospective Studies; Middle Aged; Female; Adult; Hematopoietic Stem Cell Transplantation; Aged; COVID-19; Pneumocystis carinii; Administration, Intravenous; Young Adult; SARS-CoV-2; Antifungal Agents; Trimethoprim, Sulfamethoxazole Drug Combination
PubMed: 38615824
DOI: 10.1016/j.ijid.2024.107059 -
International Journal of STD & AIDS Apr 2024Receipt of nebulised pentamidine in people with HIV was audited to identify if individuals were appropriately receiving nebulised pentamidine, and whether national...
Receipt of nebulised pentamidine in people with HIV was audited to identify if individuals were appropriately receiving nebulised pentamidine, and whether national guidelines were being followed when prophylaxis was commenced and discontinued. Of 76 people with who received nebulised pentamidine, the main indication for starting nebulised pentamidine was a co-trimoxazole adverse drug reaction. Co-trimoxazole desensitization was not attempted before starting nebulised pentamidine. The main indication for stopping nebulised pentamidine prophylaxis was when immune reconstitution occurred. This single centre audit revealed that national guidelines were being followed in most cases. The lack of information regarding the reason for starting or stopping nebulised pentamidine prophylaxis, or detail of the clinician's concerns about potential poor adherence with oral regimens of prophylaxis as a reason for choosing nebulised pentamidine prophylaxis, identifies a need for improved documentation of clinicians' decision-making. Introduction of pharmacist-led interventions/alerts using patients' electronic records, similar to those used in primary care, would enable the specialist pharmacy team to identify when and if co-trimoxazole desensitization has been offered and discussed/declined before a clinician prescribes nebulised pentamidine as well as enabling identification of those in who pentamidine prophylaxis has been continued, despite "immune reconstitution".
PubMed: 38606484
DOI: 10.1177/09564624241245155 -
Clinical Microbiology and Infection :... Jul 2024Pneumocystis jirovecii pneumonia (PCP) is a common opportunistic infection among people living with HIV (PWH), particularly among new and untreated cases. Several... (Meta-Analysis)
Meta-Analysis Comparative Study Review
Comparative efficacy and safety of Pneumocystis jirovecii pneumonia prophylaxis regimens for people living with HIV: a systematic review and network meta-analysis of randomized controlled trials.
BACKGROUND
Pneumocystis jirovecii pneumonia (PCP) is a common opportunistic infection among people living with HIV (PWH), particularly among new and untreated cases. Several regimens are available for the prophylaxis of PCP, including trimethoprim-sulfamethoxazole (TMP-SMX), dapsone-based regimens (DBRs), aerosolized pentamidine (AP), and atovaquone.
OBJECTIVES
To compare the efficacy and safety of PCP prophylaxis regimens in PWH by network meta-analysis.
METHODS
DATA SOURCES: Embase, MEDLINE, and CENTRAL from inception to June 21, 2023.
STUDY ELIGIBILITY CRITERIA
Comparative randomized controlled trials (RCTs).
PARTICIPANTS
PWH.
INTERVENTIONS
Regimens for PCP prophylaxis either compared head-to-head or versus no treatment/placebo.
ASSESSMENT OF RISK OF BIAS
Cochrane risk-of-bias tool for RCTs 2.
METHODS OF DATA SYNTHESIS
Title or abstract and full-text screening and data extraction were performed in duplicate by two independent reviewers. Data on PCP incidence, all-cause mortality, and discontinuation due to toxicity were pooled and ranked by network meta-analysis. Subgroup analyses of primary versus secondary prophylaxis, by year, and by dosage were performed.
RESULTS
A total of 26 RCTs, comprising 55 treatment arms involving 7516 PWH were included. For the prevention of PCP, TMP-SMX was ranked the most favourable agent and was superior to DBRs (risk ratio [RR] = 0.54; 95% CI, 0.36-0.83) and AP (RR = 0.53; 95% CI, 0.36-0.77). TMP-SMX was also the only agent with a mortality benefit compared with no treatment/placebo (RR = 0.79; 95% CI, 0.64-0.98). However, TMP-SMX was also ranked as the most toxic agent with a greater risk of discontinuation than DBRs (RR = 1.25; 95% CI, 1.01-1.54) and AP (7.20; 95% CI, 5.37-9.66). No significant differences in PCP prevention or mortality were detected among the other regimens. The findings remained consistent within subgroups.
CONCLUSIONS
TMP-SMX is the most effective agent for PCP prophylaxis in PWH and the only agent to confer a mortality benefit; consequently, it should continue to be recommended as the first-line agent. Further studies are necessary to determine the optimal dosing of TMP-SMX to maximize efficacy and minimize toxicity.
Topics: Humans; Pneumonia, Pneumocystis; Randomized Controlled Trials as Topic; Network Meta-Analysis; Trimethoprim, Sulfamethoxazole Drug Combination; Pneumocystis carinii; HIV Infections; AIDS-Related Opportunistic Infections; Dapsone; Pentamidine; Atovaquone; Antifungal Agents; Treatment Outcome
PubMed: 38583518
DOI: 10.1016/j.cmi.2024.03.037