Genomic and Phenotypic Characterization of Experimentally Selected Resistant Leishmania donovani Reveals a Role for Dynamin-1-Like Protein in the Mechanism of Resistance to a Novel Antileishmanial Compound.

The implementation of prospective drug resistance (DR) studies in the research-and-development (R&D) pipeline is a common practice for many infectious diseases but not for neglected tropical diseases (NTDs). Here, we explored and demonstrated the importance of this approach using as paradigms Leishmania donovani, the etiological agent of visceral leishmaniasis (VL), and TCMDC-143345, a promising compound of the GlaxoSmithKline (GSK) "Leishbox" to treat VL. We experimentally selected resistance to TCMDC-143345 in vitro and characterized resistant parasites at the genomic and phenotypic levels. We found that it took more time to develop resistance to TCMDC-143345 than to other drugs in clinical use and that there was no cross-resistance to these drugs, suggesting a new and unique mechanism. By whole-genome sequencing, we found two mutations in the gene encoding the L. donovani dynamin-1-like protein (LdoDLP1) that were fixed at the highest drug pressure. Through phylogenetic analysis, we identified LdoDLP1 as a family member of the dynamin-related proteins, a group of proteins that impacts the shapes of biological membranes by mediating fusion and fission events, with a putative role in mitochondrial fission. We found that L. donovani lines genetically engineered to harbor the two identified LdoDLP1 mutations were resistant to TCMDC-143345 and displayed altered mitochondrial properties. By homology modeling, we showed how the two LdoDLP1 mutations may influence protein structure and function. Taken together, our data reveal a clear involvement of LdoDLP1 in the adaptation/reduced susceptibility of L. donovani to TCMDC-143345. IMPORTANCE Humans and their pathogens are continuously locked in a molecular arms race during which the eventual emergence of pathogen drug resistance (DR) seems inevitable. For neglected tropical diseases (NTDs), DR is generally studied retrospectively once it has already been established in clinical settings. We previously recommended to keep one step ahead in the host-pathogen arms race and implement prospective DR studies in the R&D pipeline, a common practice for many infectious diseases but not for NTDs. Here, using Leishmania donovani, the etiological agent of visceral leishmaniasis (VL), and TCMDC-143345, a promising compound of the GSK Leishbox to treat VL, as paradigms, we experimentally selected resistance to the compound and proceeded to genomic and phenotypic characterization of DR parasites. The results gathered in the present study suggest a new DR mechanism involving the L. donovani dynamin-1-like protein (LdoDLP1) and demonstrate the practical relevance of prospective DR studies.

Dexamethasone-Induced FKBP51 Expression in CD4+ T-Lymphocytes Is Uniquely Associated With Worse Asthma Control in Obese Children With Asthma.

Introduction: There is evidence that obesity, a risk factor for asthma severity and morbidity, has a unique asthma phenotype which is less atopic and less responsive to inhaled corticosteroids (ICS). Peripheral blood mononuclear cells (PBMC) are important to the immunologic pathways of obese asthma and steroid resistance. However, the cellular source associated with steroid resistance has remained elusive. We compared the lymphocyte landscape among obese children with asthma to matched normal weight children with asthma and assessed relationship to asthma control. Methods: High-dimensional flow cytometry of PBMC at baseline and after dexamethasone stimulation was performed to characterize lymphocyte subpopulations, T-lymphocyte polarization, proliferation (Ki-67+), and expression of the steroid-responsive protein FK506-binding protein 51 (FKBP51). T-lymphocyte populations were compared between obese and normal-weight participants, and an unbiased, unsupervised clustering analysis was performed. Differentially expressed clusters were compared with asthma control, adjusted for ICS and exhaled nitric oxide. Results: In the obese population, there was an increased cluster of CD4+ T-lymphocytes expressing Ki-67 and FKBP51 at baseline and CD4+ T-lymphocytes expressing FKBP51 after dexamethasone stimulation. CD4+ Ki-67 and FKBP51 expression at baseline showed no association with asthma control. Dexamethasone-induced CD4+ FKBP51 expression was associated with worse asthma control in obese participants with asthma. FKBP51 expression in CD8+ T cells and CD19+ B cells did not differ among groups, nor did polarization profiles for Th1, Th2, Th9, or Th17 percentage. Discussion: Dexamethasone-induced CD4+ FKBP51 expression is uniquely associated with worse asthma control in obese children with asthma and may underlie the corticosteroid resistance observed in this population.

Monoclonal antibodies for the treatment of COVID-19 patients: An umbrella to overcome the storm?

The world is facing up the most considerable vaccination effort in history to end the Coronavirus disease 2019 (COVID-19) pandemic. Several monoclonal antibodies (mAbs) direct against the Receptor binding domain of the S protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) received an Emergency Use Authorization for outpatient management of mild to moderate manifestation from COVID-19. MAbs could prevent the transmission SARS-CoV-2 infection and protect individuals from progression to severe disease. Under the pressure of different treatment strategies, SARS-CoV-2 has been demonstrated to select for different sets of mutations named "variants" that could impair the effectiveness of mAbs by modifying target epitopes. We provide an overview of both completed and unpublished, or ongoing clinical trials of mAbs used and review state of art in order to describe clinical options, possible indications, and the place in therapy for these agents in the treatment of COVID-19 with a particular focus on anti-spike agents. Then, we reassume the current evidence on mutations of the SARS-CoV-2 that might confer resistance to neutralization by multiple mAbs.

Enhanced Gut-Homing Dynamics and Pronounced Exhaustion of Mucosal and Blood CD4+ T Cells in HIV-Infected Immunological Non-Responders.

Immunological non-responders (INR), a subgroup of people living with HIV (PLHIV) who fail to restore CD4+ T cell numbers upon effective antiretroviral treatment, have impaired gut mucosal barrier function and an inferior clinical prognosis compared with immunological responders (IR). The contribution of gut-homing and exhaustion of mucosal T cells to the INR phenotype was previously unknown. Flow cytometry analysis of mononuclear cells from peripheral blood and ileal and colonic lamina propria showed that INR had higher fractions of gut-homing CD4+ T cells in blood compared with IR. In addition, gut-homing cells were more likely to display signs of exhaustion in INR. The increased CD4+ T cell exhaustion in INR was ubiquitous and not restricted to subpopulations defined by activation, differentiation or regulatory T cell markers. In INR, colon CD4+ T cell exhaustion correlated negatively with the fraction of CD4+ T cells in the same compartment, this was not apparent in the ileum. The fraction of exhausted mucosal CD4+ T cells correlated with I-FABP and REG3α, markers of enterocyte damage. We conclude that alterations of gut-homing and exhaustion of T cells may contribute to impaired gut immune and barrier functions associated with immunological non-response in PLHIV.

Whole-genome sequencing as a tool for studying the microevolution of drug-resistant serial Mycobacterium tuberculosis isolates.

Treatment of drug-resistant tuberculosis requires extended use of more toxic and less effective drugs and may result in retreatment cases due to failure, abandonment or disease recurrence. It is therefore important to understand the evolutionary process of drug resistance in Mycobacterium tuberculosis. We here in describe the microevolution of drug resistance in serial isolates from six previously treated patients. Drug resistance was initially investigated through phenotypic methods, followed by genotypic approaches. The use of whole-genome sequencing allowed the identification of mutations in the katG, rpsL and rpoB genes associated with drug resistance, including the detection of rare mutations in katG and mixed populations of strains. Molecular docking simulation studies of the impact of observed mutations on isoniazid binding were also performed. Whole-genome sequencing detected 266 single nucleotide polymorphisms between two isolates obtained from one patient, suggesting a case of exogenous reinfection. In conclusion, sequencing technologies can detect rare mutations related to drug resistance, identify subpopulations of resistant strains, and identify diverse populations of strains due to exogenous reinfection, thus improving tuberculosis control by guiding early implementation of appropriate clinical and therapeutic interventions.

Immune selection suppresses the emergence of drug resistance in malaria parasites but facilitates its spread.

Although drug resistance in Plasmodium falciparum typically evolves in regions of low transmission, resistance spreads readily following introduction to regions with a heavier disease burden. This suggests that the origin and the spread of resistance are governed by different processes, and that high transmission intensity specifically impedes the origin. Factors associated with high transmission, such as highly immune hosts and competition within genetically diverse infections, are associated with suppression of resistant lineages within hosts. However, interactions between these factors have rarely been investigated and the specific relationship between adaptive immunity and selection for resistance has not been explored. Here, we developed a multiscale, agent-based model of Plasmodium parasites, hosts, and vectors to examine how host and parasite dynamics shape the evolution of resistance in populations with different transmission intensities. We found that selection for antigenic novelty ("immune selection") suppressed the evolution of resistance in high transmission settings. We show that high levels of population immunity increased the strength of immune selection relative to selection for resistance. As a result, immune selection delayed the evolution of resistance in high transmission populations by allowing novel, sensitive lineages to remain in circulation at the expense of the spread of a resistant lineage. In contrast, in low transmission settings, we observed that resistant strains were able to sweep to high population prevalence without interference. Additionally, we found that the relationship between immune selection and resistance changed when resistance was widespread. Once resistance was common enough to be found on many antigenic backgrounds, immune selection stably maintained resistant parasites in the population by allowing them to proliferate, even in untreated hosts, when resistance was linked to a novel epitope. Our results suggest that immune selection plays a role in the global pattern of resistance evolution.

Non-epidemic HCV genotypes in low- and middle-income countries and the risk of resistance to current direct-acting antiviral regimens.

The hepatitis C virus (HCV) is an extremely diverse virus, subtypes of which are distributed variably around the world. Viral genotypes may be divided into epidemic subtypes; those that have become prevalent globally, and endemic subtypes that have a more limited distribution, mainly in Africa and Asia. The high variability of endemic strains reflects evolutionary origins in the locations where they are found. This increased genetic diversity raises the possibility of resistance to pan-genotypic direct-acting antiviral regimens. While many endemic subtypes respond well to direct-acting antiviral therapies, others, for example genotypes 1l, 3b and 4r, do not respond as well as predicted. Many genotypes that are rare in high-income countries but common in other parts of the world have not yet been fully assessed in clinical trials. Further sequencing and clinical studies in sub-Saharan Africa and Asia are indicated to monitor response to treatment and to facilitate the World Health Organization's 2030 elimination strategy.

Linkage of resistance-associated substitutions in GT1 sofosbuvir + NS5A inhibitor failures treated with glecaprevir/pibrentasvir.

BACKGROUND & AIMS: Retreatment with glecaprevir/pibrentasvir (G/P) resulted in a rate of sustained virologic response 12 weeks after treatment completion (SVR12) of >90% in HCV genotype 1 (GT1) patients who previously failed a regimen of sofosbuvir plus an NS5A inhibitor (NS5Ai). This study investigated the prevalence and impact of baseline NS3 and NS5A resistance-associated substitutions (RASs) on the efficacy of G/P in prior GT1 sofosbuvir+NS5Ai failures and the persistence of treatment-emergent RASs. METHODS: Longitudinal samples from 177 patients enrolled in a phase IIIb, randomized pragmatic clinical trial were analyzed. Patients without cirrhosis were randomized to 12 or 16 weeks of G/P, and patients with compensated cirrhosis were randomized to G/P and ribavirin for 12 weeks or G/P for 16 weeks. Linkage of RAS was identified using Primer-ID next-generation sequencing at a 15% cut-off. RESULTS: Of 177 patients, 169 (95.5%) were PI-naïve. All 33 GT1b-infected patients achieved SVR12. In GT1a-infected patients, baseline NS5A RASs were prevalent (74.5%, 105/141) but NS3 RASs were uncommon. Baseline NS3 RASs had no impact on G/P efficacy and patients with baseline NS5A RASs showed a numerically but not statistically significantly lower SVR12 rate compared to those without NS5A RASs (89% vs. 97%). SVR12 was achieved in 34 of 35 (97%) patients without NS5A baseline substitution, and 53 of 57 (93%), 35 of 40 (88%), 5 of 8 (63%) with single, double-linked, and triple-linked NS5A substitutions, respectively. Among 13 patients with virologic failure, 4 acquired treatment-emergent NS3 RASs and 10 acquired NS5A RASs. CONCLUSION: Baseline NS5A RASs were highly prevalent. The presence of an increasing number of linked NS5A RASs in GT1a showed a trend in decreasing SVR12 rates, although no specific NS5A RASs or their linkage pattern were associated with lower SVR12 rates. LAY SUMMARY: Direct-acting antivirals have revolutionized the treatment of chronic hepatitis C infection, but treatment failure occurs in some patients. Retreatment of patients who previously failed a regimen consisting of sofosbuvir and an NS5A inhibitor with a regimen of glecaprevir and pibrentasvir (G/P) is >90% effective. Herein, we analyzed samples from these patients and showed that retreatment efficacy with G/P is lower in patients with double- or triple-linked NS5A resistance mutations than in patients with single or no NS5A resistance mutations. CLINICAL TRIAL NUMBER: NCT03092375.

Predictive Value of Serum Lipid for Intravenous Immunoglobulin Resistance and Coronary Artery Lesion in Kawasaki Disease.

CONTEXT: Intravenous immunoglobulin (IVIG) resistance and coronary artery lesions (CALs) prediction are pivotal topic of interests in Kawasaki disease (KD). However, data on the predictive value of lipid profile for both IVIG resistance and CALs are limited. PURPOSE: To investigate the predictive validity of lipid profile for IVIG resistance and CALs in KD. DESIGN: Prospective cohort study. SETTING: West China Second University Hospital. PATIENTS: 363 KD patients were divided into the initial IVIG-resistant group and initial IVIG-responsive group; repeated IVIG-resistant group and repeated IVIG-responsive group; CAL+ group and CAL- group. MAIN OUTCOME MEASURES: Validity of lipid profile in predicting IVIG resistance and CALs. RESULTS: Triglycerides were significantly higher whereas total cholesterol (TC), high-densisty lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein A (Apo A) were significantly lower in initial IVIG-resistant subjects, with cut-off values of 1.625 mmol/L, 3.255 mmol/L, 0.475 mmol/L, 1.965 mmol/L, and 0.665 g/L, yielding sensitivities of 52%, 70%, 52%, 61%, and 50% and specificities of 68%, 53%, 78%, 71%, and 81%, respectively. TC, LDL-C, and Apo A levels were significantly lower in repeated IVIG-resistant subjects, with cut-off values of 3.20 mmol/L, 1.78 mmol/L, and 0.605 g/L, producing sensitivities of 91%, 70%, and 57% and specificities of 55%, 67%, and 70%, respectively. Apo A level was significantly lower in the CAL+ group, with cut-off value of 0.805 g/L, yielding sensitivity of 66% and specificity of 54%. CONCLUSIONS: Lipid profiles were significantly dysregulated in KD patients suffering IVIG resistance and CALs. Some of them, such as LDL-C and Apo A, could serve as complementary laboratory markers for predicting both IVIG resistance and CALs.

Primary immunodeficiency and chronic mucocutaneous candidiasis: pathophysiological, diagnostic, and therapeutic approaches

Chronic mucocutaneous candidiasis (CMC) is characterized by a chronic or recurrent non-invasive infection, mainly due to Candida albicans, in skin, nails, and mucous membranes, associated in some cases with autoimmune manifestations. The key immune defect is a disruption of the action of cytokine IL-17, whose most common genetic etiology is STAT1 gene gain-of-function (GOF) mutations. The initial appropriate treatment for fungal infections is with azoles. However, the frequent occurrence of drug resistance is the main limitation. Therefore, identification of the underlying inborn error if immunity in CMC may allow to widen therapeutic options aimed at restoring immunological function. Type I and II Janus kinase-inhibitors have been shown to control CMC in cases associated with STAT1 GOF. In this review, we delve into the pathogenesis of CMC and the underlying immune mechanisms. We describe the reported genetic defects in which CMC is the main manifestation. Diagnostic and therapeutic approaches for these patients are also offered

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Steroid-resistant human inflammatory ILC2s are marked by CD45RO and elevated in type 2 respiratory diseases.

Group 2 innate lymphoid cells (ILC2s) orchestrate protective type 2 immunity and have been implicated in various immune disorders. In the mouse, circulatory inflammatory ILC2s (iILC2s) were identified as a major source of type 2 cytokines. The human equivalent of the iILC2 subset remains unknown. Here, we identify a human inflammatory ILC2 population that resides in inflamed mucosal tissue and is specifically marked by surface CD45RO expression. CD45RO+ ILC2s are derived from resting CD45RA+ ILC2s upon activation by epithelial alarmins such as IL-33 and TSLP, which is tightly linked to STAT5 activation and up-regulation of the IRF4/BATF transcription factors. Transcriptome analysis reveals marked similarities between human CD45RO+ ILC2s and mouse iILC2s. Frequencies of CD45RO+ inflammatory ILC2 are increased in inflamed mucosal tissue and in the circulation of patients with chronic rhinosinusitis or asthma, correlating with disease severity and resistance to corticosteroid therapy. CD45RA-to-CD45RO ILC2 conversion is suppressed by corticosteroids via induction of differentiation toward an immunomodulatory ILC2 phenotype characterized by low type 2 cytokine and high amphiregulin expression. Once converted, however, CD45RO+ ILC2s are resistant to corticosteroids, which is associated with metabolic reprogramming resulting in the activation of detoxification pathways. Our combined data identify CD45RO+ inflammatory ILC2s as a human analog of mouse iILC2s linked to severe type 2 inflammatory disease and therapy resistance.

Structure of trypanosome coat protein VSGsur and function in suramin resistance.

Suramin has been a primary early-stage treatment for African trypanosomiasis for nearly 100 yr. Recent studies revealed that trypanosome strains that express the variant surface glycoprotein (VSG) VSGsur possess heightened resistance to suramin. Here, we show that VSGsur binds tightly to suramin but other VSGs do not. By solving high-resolution crystal structures of VSGsur and VSG13, we also demonstrate that these VSGs define a structurally divergent subgroup of the coat proteins. The co-crystal structure of VSGsur with suramin reveals that the chemically symmetric drug binds within a large cavity in the VSG homodimer asymmetrically, primarily through contacts of its central benzene rings. Structure-based, loss-of-contact mutations in VSGsur significantly decrease the affinity to suramin and lead to a loss of the resistance phenotype. Altogether, these data show that the resistance phenotype is dependent on the binding of suramin to VSGsur, establishing that the VSG proteins can possess functionality beyond their role in antigenic variation.

Has2 Regulates the Development of Ovalbumin-Induced Airway Remodeling and Steroid Insensitivity in Mice.

HAS2 is a member of the gene family encoding the hyaluronan synthase 2, which can generate high-molecular-weight hyaluronan (HMW-HA). Our previous study identified HAS2 as a candidate gene for increased susceptibility to adult asthma. However, whether HAS2 dysfunction affects airway remodeling and steroid insensitivity is still limited. Therefore, this study aimed to clarify the Has2 dysfunction, triggering severe airway remodeling and steroid insensitivity in a murine model of asthma. Has2 heterozygous-deficient (Has2+/-) mice and their wild-type littermates have been evaluated in a model of chronic ovalbumin (OVA) sensitization and challenge. Mice present a higher sensitivity to OVA and higher IL-17 release as well as eosinophilic infiltration. RNA sequencing demonstrated the downregulation of EIF2 signaling pathways, TGF-ß signaling pathways, and heat shock proteins with Th17 bias in Has2+/--OVA mice. The combined treatment with anti-IL-17A antibody and dexamethasone reduces steroid insensitivity in Has2+/--OVA mice. Has2 attenuation worsens eosinophilic airway inflammation, airway remodeling, and steroid insensitivity. These data highlight that HAS2 and HMW-HA are important for controlling intractable eosinophilic airway inflammation and remodeling and could potentially be exploited for their therapeutic benefits in patients with asthma.

The drug resistance mechanisms in Leishmania donovani are independent of immunosuppression.

The protozoan parasite L. donovani resides inside macrophages as amastigotes and inflicts a potentially lethal disease visceral leishmaniasis (VL). Due to absence of a vaccine, chemotherapy with antimonials, amphotericin B, miltefosine or paromomycin remains the only option for treating VL. Prolonged treatment with a single drug resulted in parasite strains resistant to each of these drugs. As immuno-suppression characterizes the disease, we examined whether eliciting immunosuppressive cytokines is a mechanism of manifestation of drug-resistance. We infected BALB/c mice with the clinical isolates of L. donovani- BHU1066 (sensitive), NS2 (antimony-resistant), BHU1064 (miltefosine-resistant), BHU919 (Amphotericin B-resistant) and BHU1020 (paromomycin-resistant)- from the respective drug-unresponsive patients and assessed splenic parasite load and production of pro-inflammatory and anti-inflammatory cytokines. Although the splenic parasite loads in the drug-resistant L. donovani-infected BALB/c mice were higher than that observed in the drug-sensitive parasites-infected mice, the cytokine profiles were not significantly different between these two sets of mice. The drug-resistance in L. donovani results from innate drug modulation but perhaps not from host immune-suppressive cytokines.

Low-dose or no aspirin administration in acute-phase Kawasaki disease: a meta-analysis and systematic review.

OBJECTIVE: To compare the efficacy of low-dose or no aspirin with conventional high-dose aspirin for the initial treatment in the acute-phase of Kawasaki disease (KD). DESIGN: A meta-analysis and systematic review of randomised control trials and cohort studies. METHODS: All available articles that compared different dosage of aspirin in the acute-phase of KD published until 20 September 2019 were included from the databases of PubMed, Embase and Cochrane Central Register of Controlled Trials Central without language restrictions. Extracted data from eligible studies were reviewed by two authors independently and analysed by using RStudio software. RESULTS: Nine cohorts with a total of 12 182 children were enrolled. We found that low-dose (3-5 mg/kg/day) or no aspirin in the acute-phase KD was associated with reducing the risk of coronary artery lesions (CALs, OR=0.81, 95% CI 0.69 to 0.95). No differences were observed in intravenous immunoglobulin resistance, length of hospital stay and fever days after admission (OR=1.35, 95% CI 0.91 to 1.98; standard mean difference (SMD)=0.17, 95% CI -1.07 to 1.4; SMD=0.3, 95% CI -1.51 to 2.11) in the low-dose/no aspirin subgroup compared with the high-dose (≥30 mg/kg/day) aspirin subgroup. We did not identify any potential factors affecting the homogeneity of CAL risk as well as clinical important effects in all included studies. CONCLUSIONS: Prescribing low-dose or no aspirin in the acute-phase of KD might be associated with a decreased incidence of CAL. However, additional well-designed prospective trials are required to support the theory.

Brain-homing CD4+ T cells display glucocorticoid-resistant features in MS.

OBJECTIVE: To study whether glucocorticoid (GC) resistance delineates disease-relevant T helper (Th) subsets that home to the CNS of patients with early MS. METHODS: The expression of key determinants of GC sensitivity, multidrug resistance protein 1 (MDR1/ABCB1) and glucocorticoid receptor (GR/NR3C1), was investigated in proinflammatory Th subsets and compared between natalizumab-treated patients with MS and healthy individuals. Blood, CSF, and brain compartments from patients with MS were assessed for the recruitment of GC-resistant Th subsets using fluorescence-activated cell sorting (FACS), quantitative polymerase chain reaction (qPCR), immunohistochemistry, and immunofluorescence. RESULTS: An MS-associated Th subset termed Th17.1 showed a distinct GC-resistant phenotype as reflected by high MDR1 and low GR expression. This expression ratio was further elevated in Th17.1 cells that accumulated in the blood of patients with MS treated with natalizumab, a drug that prevents their entry into the CNS. Proinflammatory markers C-C chemokine receptor 6, IL-23R, IFN-γ, and GM-CSF were increased in MDR1-expressing Th17.1 cells. This subset predominated the CSF of patients with early MS, which was not seen in the paired blood or in the CSF from patients with other inflammatory and noninflammatory neurologic disorders. The potential of MDR1-expressing Th17.1 cells to infiltrate brain tissue was confirmed by their presence in MS white matter lesions. CONCLUSION: This study reveals that GC resistance coincides with preferential CNS recruitment of pathogenic Th17.1 cells, which may hamper the long-term efficacy of GCs in early MS.

Identificación de los mecanismos resistencia enzimáticos en uropatógenos de pacientes ambulatorios de un hospital público de San Lorenzo, Paraguay; 2015-2019 / Identification of enzyme resistance mechanisms in pathogens from an outpatient clinic in a public hospital in San Lorenzo, Paraguay; 2015-2019

Introducción: El propósito del estudio es determinar en los urocultivos, la prevalencia de los mecanismos enzimáticos de resistencia encontrados in vitro. Materiales y métodos: Se realizó un estudio retrospectivo, de ambos sexos, mayores de 18 años, que acudieron al Consultorio Externo de Clínica Médica y Urgencias por síntomas de infección urinaria. Se incluyeron todos los urocultivos en los que se aislaron uropatógenos con recuento ≥ 105 UFC/mL. Se excluyeron los urocultivos polimicrobianos, los que no contaban con antibiograma o aquellos con datos clínicos incompletos. Resultados: Se identificaron 1031 urocultivos que cumplieron con los criterios establecidos para la realización del estudio. El 56% correspondió al sexo femenino y el 43% al masculino. La edad media de las mujeres fue de 52± 20 años y el de los hombres fue de 62±16 años. Los uropatógenos más frecuentes fueron Escherichia coli 553 (52% en promedio) seguida de Klebsiella pneumoniae con 148 (14% en promedio). Urocultivos de varones: El principal mecanismo de resistencia de Escherichia coli fueron las BLEE, 55 aislamientos (91%); seguida de las MBL, 3 aislamientos (5%) y KPC, 2 aislamientos (3%). En Klebsiella pneumoniae en 53 aislamientos se puedo observar: BLEE, 31 aislamientos (58%); seguida de las KPC 13 aislamientos (25%) y MBL, 9 aislamientos en (16%). Urocultivos en mujeres: Las enzimas de Escherichia coli fueron 81 aislamientos, de los cuales fueron BLEE, 79 aislamientos (97%); seguido de las KPC, 1 aislamiento (1%) y las MBL, 1 aislamiento (1%). En Klebsiella pneumoniae se pudo observar los siguientes mecanismos enzimáticos en base a 35 aislamientos; BLEE, 19 aislamientos (54%), seguida de las KPC, 12 aislamientos (34%) y por último, MBL, 4 aislamientos (13%). Conclusión: En las IVU de nuestro estudio, Escherichia coli y Klebsiella pneumoniae fueron las principales bacterias que originan resistencia a los antibióticos y la BLEE fue la enzima más frecuentemente identificada en ambos sexos.

Introduction: The objective of this study was to assess frequency of enzymatic resistance mechanisms isolated from community urinary tract infections (UTI) determined in vitro in urine cultures. Objectives: This is a retrospective study, a total of 1031 urine samples were included from patients with urinary tract infection who had consulted at the Outpatient Clinic and Emergencies Services. The following information was recorded, age, sex, urine sample. All urine cultures in which pathogens with a count of ≥ 105 CFU / mL were included. Were excluded polymicrobial urine cultures, those without an antibiogram or those with incomplete clinical data. Results: A total of 1031 urine samples met inclusion criteria, 56% of patients were female and 43% male. The mean age of the women was 52 ± 20 years and in men was 62 ± 16 years. 553 (52%) E. coli and 148 (14%) Klebsiella strains were isolated from community samples. Male urine cultures: The main resistance mechanism of Escherichia coli was ESBLs, 55 isolates (91%); followed by MBL, 3 isolates (5%) and KPC, 2 isolates (3%). In Klebsiella pneumoniae (53 isolates); ESBL, 31 isolates (58%); followed by KPC 13 isolates (25%) and MBL, 9 isolates in (16%). Female urine culture: Escherichia coli enzymes 81 isolates, of which ESBLs were 79 isolates (97%); followed by KPC, 1 isolate (1%) and MBL, 1 isolate (1%). In Klebsiella pneumoniae the following enzymatic mechanisms could be observed based on 35 isolates; ESBL, 19 isolates (54%), followed by KPCs, 12 isolates (34%) and finally, MBL, 4 isolates (13%). Conclusion: The result of our study showed high prevalence of Escherichia coli and Klebsiella pneumoniae causing resistance to antibiotics in culture bacteria from urine samples of patients with UTI, and ESBL was the main ß-lactamase resistance mechanism in Klebsiella and E. coli isolates in both male and female.

Mechanism of acquired resistance to nivolumab in lung squamous cell carcinoma: case report and review of the literature.

Background: Immune checkpoint inhibitors targeting PD-1 and PD-L1 have noticeably improved the treatment landscape of advanced non-small-cell lung cancer, including lung squamous cell carcinoma (SCC). Although patients with immune checkpoint therapy can achieve long-term survival, acquired resistance has been recognized more frequently, while the underlying mechanisms are currently poorly understood. Materials and methods: Here, we report a patient with metastatic lung SCC treated with nivolumab as a first-line treatment for 28 months. Conclusion: The analysis of specimens prenivolumab and postnivolumab treatment suggests that genetic alterations in SOX2 and CDKN2A/CDKN2B and changes in the tumor microenvironment could be reasons for the acquired resistance to nivolumab observed in the lung SCC patient.

Unfavorable impact of anti-rituximab antibodies on clinical outcomes in children with complicated steroid-dependent nephrotic syndrome.

BACKGROUND: Anti-rituximab antibodies (ARA) are associated not only with adverse events, such as infusion reactions (IR) and serum sickness, but also with rituximab efficacy. However, the clinical relevance of ARA in children with steroid-dependent nephrotic syndrome (SDNS) remains unknown. METHODS: We retrospectively reviewed clinical outcomes of 13 children with complicated SDNS receiving repeated single-dose rituximab treatments at 375 mg/m2 to assess whether ARA formation could impact toxicity and efficacy of additional rituximab. Pre-rituximab 22 samples collected from patients who developed IR during the second or subsequent rituximab doses were measured by electrochemiluminescence analysis. RESULTS: ARA were identified in 5 of 13 patients (9 of 22 samples). Median time to recovery of CD19+ B cells to > 1% of total lymphocytes and median relapse-free time after rituximab treatment were significantly shorter in the 9 ARA-positive samples than the 13 ARA-negative samples (41 vs. 100 days, p < 0.01 and 119 vs. 308 days, p < 0.05, respectively). Kaplan-Meier analysis showed that time to CD19+ B cell recovery after rituximab was significantly shorter in ARA-positive samples than in ARA-negative samples (p < 0.005). Severe IR developed in two ARA-positive patients and serum sickness in one ARA-positive patient. CONCLUSIONS: The incidence of ARA formation was high in the pre-rituximab samples of patients with complicated SDNS who developed IR during the second or subsequent rituximab doses, suggesting that ARA formation might have an unfavorable impact on the toxicity and efficacy of additional rituximab doses in these patients.