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Antimicrobial Agents and Chemotherapy Jun 2024Intrinsic resistance to macrolides in Gram-negative bacteria is primarily attributed to the low permeability of the outer membrane, though the underlying genetic and...
Intrinsic resistance to macrolides in Gram-negative bacteria is primarily attributed to the low permeability of the outer membrane, though the underlying genetic and molecular mechanisms remain to be fully elucidated. Here, we used transposon directed insertion-site sequencing (TraDIS) to identify chromosomal non-essential genes involved in intrinsic resistance to a macrolide antibiotic, tilmicosin. We constructed two highly saturated transposon mutant libraries of >290,000 and >390,000 unique Tn5 insertions in a clinical enterotoxigenic strain (ETEC5621) and in a laboratory strain (K-12 MG1655), respectively. TraDIS analysis identified genes required for growth of ETEC5621 and MG1655 under 1/8 MIC ( = 15 and 16, respectively) and 1/4 MIC ( = 38 and 32, respectively) of tilmicosin. For both strains, 23 genes related to lipopolysaccharide biosynthesis, outer membrane assembly, the Tol-Pal system, efflux pump, and peptidoglycan metabolism were enriched in the presence of the antibiotic. Individual deletion of genes ( = 10) in the wild-type strains led to a 64- to 2-fold reduction in MICs of tilmicosin, erythromycin, and azithromycin, validating the results of the TraDIS analysis. Notably, deletion of or , which impairs the outer membrane, led to the most significant decreases in MICs of all three macrolides in ETEC5621. Our findings contribute to a genome-wide understanding of intrinsic macrolide resistance in , shedding new light on the potential role of the peptidoglycan layer. They also provide an proof of concept that can be sensitized to macrolides by targeting proteins maintaining the outer membrane such as SurA and WaaG.
PubMed: 38940570
DOI: 10.1128/aac.00452-24 -
Frontiers in Bioscience (Landmark... Jun 2024The inhibitors of mammalian target of rapapmycin (mTOR), everolimus, temsirolimus and rapamycin, have a wide range of clinical utility; however, as is inevitably the... (Review)
Review
The inhibitors of mammalian target of rapapmycin (mTOR), everolimus, temsirolimus and rapamycin, have a wide range of clinical utility; however, as is inevitably the case with other chemotherapeutic agents, resistance development constrains their effectiveness. One putative mechanism of resistance is the promotion of autophagy, which is a direct consequence of the inhibition of the mTOR signaling pathway. Autophagy is primarily considered to be a cytoprotective survival mechanism, whereby cytoplasmic components are recycled to generate energy and metabolic intermediates. The autophagy induced by everolimus and temsirolimus appears to play a largely protective function, whereas a cytotoxic function appears to predominate in the case of rapamycin. In this review we provide an overview of the autophagy induced in response to mTOR inhibitors in different tumor models in an effort to determine whether autophagy targeting could be of clinical utility as adjuvant therapy in association with mTOR inhibition.
Topics: Humans; Autophagy; TOR Serine-Threonine Kinases; MTOR Inhibitors; Animals; Neoplasms; Signal Transduction; Antineoplastic Agents; Cytoprotection; Sirolimus
PubMed: 38940039
DOI: 10.31083/j.fbl2906231 -
Open Forum Infectious Diseases Jun 2024Antimicrobial resistance (AMR) is a global threat to infectious disease control, particularly among recently hospitalized children. We sought to determine the prevalence...
BACKGROUND
Antimicrobial resistance (AMR) is a global threat to infectious disease control, particularly among recently hospitalized children. We sought to determine the prevalence and mitigating factors of resistance in enteric among children discharged from health facilities in western Kenya.
METHODS
Between June 2016 and November 2019, children aged 1 to 59 months were enrolled at the point of discharge from the hospital. was isolated by microbiological culture from rectal swabs at baseline. β-Lactamases and macrolide resistance-conferring genes were detected by polymerase chain reaction. A modified Poisson regression model was used to assess the predictors (A) and CTX-M-type extended-spectrum β-lactamase (ESBL).
RESULTS
Of the 238 children whose isolates were tested, 91 (38.2%) and 109 (45.8%) had detectable CTX-M-type ESBL and (A) genes, respectively. Antibiotic treatment during hospitalization (adjusted prevalence ratio [aPR], 2.47; 95% CI, 1.12-5.43; = .025), length of hospitalization (aPR, 1.42; 95% CI, 1.00-2.01; = .052), and the practice of open defecation (aPR, 2.47; 95% CI, 1.40-4.36; = .002) were independent predictors for CTX-M-type ESBL and (A) genes. Pneumococcal vaccination was associated with a 43% lower likelihood of CTX-M-type ESBL (aPR, 0.57; 95% CI, .38-.85; = .005), while measles vaccination was associated with a 32% lower likelihood of (A) genes (aPR, 0.68; 95% CI, .49-.93; = .017) in isolates.
CONCLUSIONS
Among children discharged from the hospital, history of vaccination, shorter hospital stay, lack of in-hospital antibiotic exposure, and improved sanitation were associated with a lower likelihood of AMR genes. To mitigate the continued spread of AMR, AMR control programs should consider strategies beyond antimicrobial stewardship, including improvements in sanitation, increased vaccine coverage, and the development of novel vaccines.
PubMed: 38938894
DOI: 10.1093/ofid/ofae307 -
Open Veterinary Journal May 2024Young farm animals are susceptible to opportunistic infections which may cause economic losses due to mortality and poor weight gain. The development of antimicrobial...
BACKGROUND
Young farm animals are susceptible to opportunistic infections which may cause economic losses due to mortality and poor weight gain. The development of antimicrobial resistance and the desire to improve therapy efficacy and safety are the reasons to seek for new antibacterial drugs ensuring rapid recovery with minimum adverse events.
AIM
To estimate the efficacy of DOKSI AVZ 500 in respiratory pathologies in young pigs.
METHODS
The study was conducted in 65-70-day-old Yorkshire piglets with signs of bacterial respiratory pathologies. The animals were treated with the test drug for 3 or 5 days. The reference group received TETRAMAX 500 which is similar to the test drug in terms of chemical structure, mechanism of action, and activity spectrum. The animal's status was assessed using clinical examination, clinical blood count, and bacteriological tests.
RESULTS
Both test and reference drugs were well tolerated and ensured the animal recovery within about 4 days. The recovery was accompanied by normalization of hematological parameters and flora composition. The bacterium associated with the disease development, , was virtually completely eliminated in all groups. No adverse events were noted. After the treatment, all the animals readily gained weight and live market quality.
CONCLUSION
DOKSI AVZ 500 was a highly efficient therapy for respiratory pathologies caused by the resident opportunistic flora in piglets. It has also shown noninferiority TETRAMAX 500 in terms of all the health-related parameters and thus can be recommended for introduction in veterinary practice in pig farms.
Topics: Animals; Swine; Swine Diseases; Anti-Bacterial Agents; Respiratory Tract Infections; Female; Male; Tylosin
PubMed: 38938427
DOI: 10.5455/OVJ.2024.v14.i5.2 -
BMC Infectious Diseases Jun 2024Refractory Helicobacter pylori (H. pylori) infection inevitably increase the difficulty of drug selection. Here, we described our experience with the use of a novel... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Refractory Helicobacter pylori (H. pylori) infection inevitably increase the difficulty of drug selection. Here, we described our experience with the use of a novel tetravalent IgY against H. pylori for the treatment of patients with refractory H. pylori infection.
METHODS
Patients were randomly assigned to receive the standard quadruple therapy (amoxicillin, clarithromycin, omeprazole and bismuth potassium citrate ) for 2 weeks or 250 mg of avian polyclonal IgY orally twice a day for 4 weeks. The binding efficacy of IgY to H. pylori antigens was detected by western blotting. C-urea breath test was performed to evaluate the eradication therap's efficacy. The side effects of IgY were evaluated via various routine tests. The questionnaire was used to gather clinical symptoms and adverse reactions.
RESULTS
Western blot analysis showed that tetravalent IgY simultaneously bind to VacA, HpaA, CagA and UreB of H. pylori. Tetravalent IgY had an eradication rate of 50.74% in patients with refractory H. pylori and an inhibition rate of 50.04% against DOB (delta over baseline) of C-urea. The symptom relief rate was 61.76% in thirty-four patients with clinical symptoms, and no adverse reactions were observed during tetravalent IgY treatment period.
CONCLUSIONS
Polyclonal avian tetravalent IgY reduced H. pylori infection, and showed good efficacy and safety in the treatment of refractory H. pylori infection patients, which represented an effective therapeutic option of choice for patients with refractory H. pylori infection.
Topics: Humans; Helicobacter Infections; Male; Female; Helicobacter pylori; Middle Aged; Immunoglobulins; Adult; Anti-Bacterial Agents; Treatment Outcome; Aged; Drug Therapy, Combination; Clarithromycin; Amoxicillin; Young Adult; Antibodies, Bacterial
PubMed: 38937679
DOI: 10.1186/s12879-024-09498-4 -
Scientific Reports Jun 2024Nasally colonized staphylococci carry antibiotic resistance genes and may lead to serious opportunistic infections. We are investigating nasal carriage of Staphylococcus...
Nasally colonized staphylococci carry antibiotic resistance genes and may lead to serious opportunistic infections. We are investigating nasal carriage of Staphylococcus aureus and Staphylococci other than S. aureus (SOSA) among young volunteers in Egypt to determine their risk potential. Nasal swabs collected over 1 week in June 2019 from 196 volunteers were cultured for staphylococcus isolation. The participants were interviewed to assess sex, age, general health, hospitalization and personal hygiene habits. Identification was carried out using biochemical tests and VITEK 2 automated system. Disc diffusion and minimum inhibitory concentration tests were performed to determine antibiotic susceptibility. Screening for macrolide resistance genes (ermA, ermB, ermC, ermT and msrA) was performed using polymerase chain reaction. Thirty four S. aureus and 69 SOSA were obtained. Multi-drug resistance (MDR) was detected among most staphylococcal species, ranging from 30.77% among S. hominis to 50% among S. epidermidis. Phenotypic resistance to all tested antibiotics, except for linezolid, was observed. Susceptibility to rifampicin, vancomycin and teicoplanin was highest. ermB showed the highest prevalence among all species (79.41% and 94.2% among S. aureus and SOSA, respectively), and constitutive macrolide-lincosamide-streptogramin B (MLS) resistance was equally observed in S. aureus and SOSA (11.11% and 16.22%, respectively), whereas inducible MLS resistance was more often found in S. aureus (77.78% and 43.24%, respectively). The species or resistance level of the carried isolates were not significantly associated with previous hospitalization or underlying diseases. Although over all colonization and carriage of resistance genes are within normal ranges, the increased carriage of MDR S. aureus is alarming. Also, the fact that many macrolide resitance genes were detected should be a warning sign, particularly in case of MLS inducible phenotype. More in depth analysis using whole genome sequencing would give a better insight into the MDR staphylococci in the community in Egypt.
Topics: Humans; Egypt; Female; Male; Staphylococcus; Microbial Sensitivity Tests; Staphylococcal Infections; Anti-Bacterial Agents; Adult; Phenotype; Young Adult; Genotype; Staphylococcus aureus; Drug Resistance, Multiple, Bacterial; Adolescent
PubMed: 38937465
DOI: 10.1038/s41598-024-60924-8 -
The Lancet. Oncology Jul 2024Neuroblastoma is the most common extracranial solid tumour in children. Relapsed or refractory neuroblastoma is associated with a poor outcome. We assessed the... (Randomized Controlled Trial)
Randomized Controlled Trial
Irinotecan and temozolomide in combination with dasatinib and rapamycin versus irinotecan and temozolomide for patients with relapsed or refractory neuroblastoma (RIST-rNB-2011): a multicentre, open-label, randomised, controlled, phase 2 trial.
BACKGROUND
Neuroblastoma is the most common extracranial solid tumour in children. Relapsed or refractory neuroblastoma is associated with a poor outcome. We assessed the combination of irinotecan-temozolomide and dasatinib-rapamycin (RIST) in patients with relapsed or refractory neuroblastoma.
METHODS
The multicentre, open-label, randomised, controlled, phase 2, RIST-rNB-2011 trial recruited from 40 paediatric oncology centres in Germany and Austria. Patients aged 1-25 years with high-risk relapsed (defined as recurrence of all stage IV and MYCN amplification stages, after response to treatment) or refractory (progressive disease during primary treatment) neuroblastoma, with Lansky and Karnofsky performance status at least 50%, were assigned (1:1) to RIST (RIST group) or irinotecan-temozolomide (control group) by block randomisation, stratified by MYCN status. We compared RIST (oral rapamycin [loading 3 mg/m on day 1, maintenance 1 mg/m on days 2-4] and oral dasatinib [2 mg/kg per day] for 4 days with 3 days off, followed by intravenous irinotecan [50 mg/m per day] and oral temozolomide [150 mg/m per day] for 5 days with 2 days off; one course each of rapamycin-dasatinib and irinotecan-temozolomide for four cycles over 8 weeks, then two courses of rapamycin-dasatinib followed by one course of irinotecan-temozolomide for 12 weeks) with irinotecan-temozolomide alone (with identical dosing as experimental group). The primary endpoint of progression-free survival was analysed in all eligible patients who received at least one course of therapy. The safety population consisted of all patients who received at least one course of therapy and had at least one post-baseline safety assessment. This trial is registered at ClinicalTrials.gov, NCT01467986, and is closed to accrual.
FINDINGS
Between Aug 26, 2013, and Sept 21, 2020, 129 patients were randomly assigned to the RIST group (n=63) or control group (n=66). Median age was 5·4 years (IQR 3·7-8·1). 124 patients (78 [63%] male and 46 [37%] female) were included in the efficacy analysis. At a median follow-up of 72 months (IQR 31-88), the median progression-free survival was 11 months (95% CI 7-17) in the RIST group and 5 months (2-8) in the control group (hazard ratio 0·62, one-sided 90% CI 0·81; p=0·019). Median progression-free survival in patients with amplified MYCN (n=48) was 6 months (95% CI 4-24) in the RIST group versus 2 months (2-5) in the control group (HR 0·45 [95% CI 0·24-0·84], p=0·012); median progression-free survival in patients without amplified MYCN (n=76) was 14 months (95% CI 9-7) in the RIST group versus 8 months (4-15) in the control group (HR 0·84 [95% CI 0·51-1·38], p=0·49). The most common grade 3 or worse adverse events were neutropenia (54 [81%] of 67 patients given RIST vs 49 [82%] of 60 patients given control), thrombocytopenia (45 [67%] vs 41 [68%]), and anaemia (39 [58%] vs 38 [63%]). Nine serious treatment-related adverse events were reported (five patients given control and four patients given RIST). There were no treatment-related deaths in the control group and one in the RIST group (multiorgan failure).
INTERPRETATION
RIST-rNB-2011 demonstrated that targeting of MYCN-amplified relapsed or refractory neuroblastoma with a pathway-directed metronomic combination of a multkinase inhibitor and an mTOR inhibitor can improve progression-free survival and overall survival. This exclusive efficacy in MYCN-amplified, relapsed neuroblastoma warrants further investigation in the first-line setting.
FUNDING
Deutsche Krebshilfe.
Topics: Humans; Temozolomide; Irinotecan; Antineoplastic Combined Chemotherapy Protocols; Male; Female; Neuroblastoma; Child, Preschool; Child; Dasatinib; Adolescent; Neoplasm Recurrence, Local; Infant; Adult; Sirolimus; Young Adult; Germany; Drug Resistance, Neoplasm; Progression-Free Survival
PubMed: 38936379
DOI: 10.1016/S1470-2045(24)00202-X -
The Lancet. Oncology Jul 2024The Children's Oncology Group defines intermediate-risk rhabdomyosarcoma as unresected FOXO1 fusion-negative disease arising at an unfavourable site or non-metastatic... (Randomized Controlled Trial)
Randomized Controlled Trial
Addition of temsirolimus to chemotherapy in children, adolescents, and young adults with intermediate-risk rhabdomyosarcoma (ARST1431): a randomised, open-label, phase 3 trial from the Children's Oncology Group.
BACKGROUND
The Children's Oncology Group defines intermediate-risk rhabdomyosarcoma as unresected FOXO1 fusion-negative disease arising at an unfavourable site or non-metastatic FOXO1 fusion-positive disease. Temsirolimus in combination with chemotherapy has shown promising activity in patients with relapsed or refractory rhabdomyosarcoma. We aimed to compare event-free survival in patients with intermediate-risk rhabdomyosarcoma treated with vincristine, actinomycin, and cyclophosphamide alternating with vincristine and irinotecan (VAC/VI) combined with temsirolimus followed by maintenance therapy versus VAC/VI alone with maintenance therapy.
METHODS
ARST1431 was a randomised, open-label, phase 3 trial conducted across 210 institutions in Australia, Canada, New Zealand, and the USA. Eligible patients were those aged 40 years or younger with non-metastatic FOXO1-positive rhabdomyosarcoma or unresected FOXO1-negative rhabdomyosarcoma disease from unfavourable sites. Two other groups of patients were also eligible: those who had FOXO1-negative disease at a favourable site (excluding orbit) that was unresected; and those who were aged younger than 10 years with stage IV FOXO1-negative disease with distant metastases. Eligible patients had to have a Lansky performance status score of 50 or higher if 16 years or younger and a Karnofsky performance status score of 50 or higher if older than 16 years; all patients were previously untreated. Patients were randomised (1:1) in blocks of four and stratified by histology, stage, and group. Patients received intravenous VAC/VI chemotherapy with a cyclophosphamide dose of 1·2 g/m per dose per cycle with or without a reducing dose of intravenous weekly temsirolimus starting at 15 mg/m or 0·5 mg/kg per dose for those who weighed less than 10 kg. The total duration of therapy was 42 weeks followed by 6 months of maintenance therapy with oral cyclophosphamide plus intravenous vinorelbine for all patients. Temsirolimus was withheld during radiotherapy and for 2 weeks before any major surgical procedure. The primary endpoint was 3-year event-free survival. Data were analysed with a revised intention-to-treat approach. The study is registered with ClinicalTrials.gov (NCT02567435) and is complete.
FINDINGS
Between May 23, 2016, and Jan 1, 2022, 325 patients were enrolled. In 297 evaluable patients (148 assigned to VAC/VI alone and 149 assigned to VAC/VI with temsirolimus), the median age was 6·3 years (IQR 3·0-11·3); 33 (11%) patients were aged 18 years or older; 179 (60%) of 297 were male. 113 (77%) of 148 patients were FOXO1 negative in the VAC/VI group, and 108 (73%) of 149 were FOXO1 negative in the VAC/VI with temsirolimus group. With a median follow-up of 3·6 years (IQR 2·8-4·5), 3-year event-free survival did not differ significantly between the two groups (64·8% [95% CI 55·5-74·1] in the VAC/VI group vs 66·8% [57·5-76·2] in the VAC/VI plus temsirolimus group (hazard ratio 0·86 [95% CI 0·58-1·26]; log-rank p=0·44). The most common grade 3-4 adverse events were anaemia (62 events in 60 [41%] of 148 patients in the VAC/VI group vs 89 events in 87 [58%] of 149 patients in the VAC/VI with temsirolimus group), lymphopenia (83 events in 65 [44%] vs 99 events in 71 [48%]), neutropenia (160 events in 99 [67%] vs 164 events in 105 [70%]), and leukopenia (121 events in 86 [58%] vs 132 events in 93 [62%]). There was one treatment-related death in the VAC/VI with temsirolimus group, categorised as not otherwise specified.
INTERPRETATION
Addition of temsirolimus to VAC/VI did not improve event-free survival in patients with intermediate-risk rhabdomyosarcoma defined by their FOXO1 translocation status and clinical factors. Novel biology-based strategies are needed to improve outcomes in this population.
FUNDING
The Children's Oncology Group (supported by the US National Cancer Institute, US National Institutes of Health).
Topics: Humans; Male; Female; Child; Adolescent; Antineoplastic Combined Chemotherapy Protocols; Sirolimus; Rhabdomyosarcoma; Child, Preschool; Vincristine; Young Adult; Cyclophosphamide; Adult; Dactinomycin; Irinotecan; Infant; Progression-Free Survival; Forkhead Box Protein O1
PubMed: 38936378
DOI: 10.1016/S1470-2045(24)00255-9 -
PLoS Neglected Tropical Diseases Jun 2024Lymphatic filariasis (LF) remains a significant global issue. To eliminate LF as a public health problem, the World Health Organization (WHO) recommends multiple rounds...
BACKGROUND
Lymphatic filariasis (LF) remains a significant global issue. To eliminate LF as a public health problem, the World Health Organization (WHO) recommends multiple rounds of mass drug administration (MDA). In certain scenarios, including when elimination targets have not been met with two-drug MDA, triple-drug MDA (using ivermectin, diethylcarbamazine and albendazole) is recommended. In this study, we report on antigen (Ag) and microfilaria (Mf) prevalence in eight primary sampling units (PSUs) in Samoa 4.5 years after one round of triple-drug MDA.
METHODOLOGY
In 2023, community surveys were conducted in eight PSUs that had been surveyed previously in 2018 (between 1.5 and 3.5 months post triple-drug MDA) and 2019 (six to eight-months post triple-drug MDA). Fifteen houses were randomly selected in each PSU with household members aged ≥ 5 years invited to participate. Blood samples were tested for Ag and Mf.
PRINCIPAL FINDINGS
Ag-positive participants were observed in six of the eight PSUs, and Ag prevalence was significantly above the 1% threshold in four PSUs. The presence of Mf-positive participants in five PSUs confirms the presence of residual active infections.
CONCLUSIONS/SIGNIFICANCE
This study provides evidence of persistent LF transmission in Samoa 4.5 years after one round of triple-drug MDA, confirming that one round was insufficient for interruption of transmission in this setting. Our findings highlight the negative impact of delaying MDA rounds, for example, due to public health emergencies.
Topics: Elephantiasis, Filarial; Humans; Mass Drug Administration; Albendazole; Samoa; Diethylcarbamazine; Ivermectin; Male; Female; Adult; Filaricides; Middle Aged; Adolescent; Animals; Young Adult; Child; Prevalence; Antigens, Helminth; Drug Therapy, Combination; Child, Preschool; Wuchereria bancrofti; Aged
PubMed: 38935622
DOI: 10.1371/journal.pntd.0012236 -
Zeitschrift Fur Naturforschung. C,... Jun 2024Chemical investigation of the fungal endophyte sp. isolated from leaves of , collected in Cameroon, resulted in the previously undescribed 10-membered macrolide, and...
Chemical investigation of the fungal endophyte sp. isolated from leaves of , collected in Cameroon, resulted in the previously undescribed 10-membered macrolide, and two known natural products. The structures of the xylatolides A and B were unambiguously identified by their mass spectra and by extensive 1D and 2D NMR spectroscopic analysis, featuring a 10-membered lactone core structure with oxygenated substituents and an unsubstituted 10-alkyl chain presenting seven carbon atoms. Compounds were screened for their cytotoxic potential against the human HepG2 hepatocellular carcinoma cells and HCT-116 cells (human colon carcinoma cell line). Moreover, the isolated compounds were also assayed against a small panel of sensitive strains including the bacterial species , , and as well as against the fungal species . However, no significant activities were found.
PubMed: 38934215
DOI: 10.1515/znc-2023-0091