Cefiderocol: Clinical application and emergence of resistance.

Antibacterial drug resistance of gram-negative bacteria (GNB) results in high morbidity and mortality of GNB infection, seriously threaten human health globally. Developing new antibiotics has become the critical need for dealing with drug-resistant bacterial infections. Cefiderocol is an iron carrier cephalosporin that achieves drug accumulation through a unique "Trojan horse" strategy into the bacterial periplasm. It shows high antibacterial activity against multidrug-resistant (MDR) Enterobacteriaceae and MDR non-fermentative bacteria. The application of cefiderocol offers new hope for treating clinical drug-resistant bacterial infections. However, limited clinical data and uncertainties about its resistance mechanisms constrain the choice of its therapeutic use. This review aimed to summarize the clinical applications, drug resistance mechanisms, and co-administration of cefiderocol.

Correlation between antimicrobial resistance, biofilm formation, and virulence determinants in uropathogenic Escherichia coli from Egyptian hospital.

BACKGROUND: Uropathogenic Escherichia coli (UPEC) is the main etiological agent behind community-acquired and hospital-acquired urinary tract infections (UTIs), which are among the most prevalent human infections. The management of UPEC infections is becoming increasingly difficult owing to multi-drug resistance, biofilm formation, and the possession of an extensive virulence arsenal. This study aims to characterize UPEC isolates in Tanta, Egypt, with regard to their antimicrobial resistance, phylogenetic profile, biofilm formation, and virulence, as well as the potential associations among these factors. METHODS: One hundred UPEC isolates were obtained from UTI patients in Tanta, Egypt. Antimicrobial susceptibility was assessed using the Kirby-Bauer method. Extended-spectrum ß-lactamases (ESBLs) production was screened using the double disk synergy test and confirmed with PCR. Biofilm formation was evaluated using the microtiter-plate assay and microscopy-based techniques. The phylogenetic groups of the isolates were determined. The hemolytic activity, motility, siderophore production, and serum resistance of the isolates were also evaluated. The clonal relatedness of the isolates was assessed using ERIC-PCR. RESULTS: Isolates displayed elevated resistance to cephalosporins (90-43%), sulfamethoxazole-trimethoprim (63%), and ciprofloxacin (53%). Ninety percent of the isolates were multidrug-resistant (MDR)/ extensively drug-resistant (XDR) and 67% produced ESBLs. Notably, there was an inverse correlation between biofilm formation and antimicrobial resistance, and 31%, 29%, 32%, and 8% of the isolates were strong, moderate, weak, and non-biofilm producers, respectively. Beta-hemolysis, motility, siderophore production, and serum resistance were detected in 64%, 84%, 65%, and 11% of the isolates, respectively. Siderophore production was correlated to resistance to multiple antibiotics, while hemolysis was more prevalent in susceptible isolates and associated with stronger biofilms. Phylogroups B2 and D predominated, with lower resistance and stronger biofilms in group B2. ERIC-PCR revealed considerable diversity among the isolates. CONCLUSION: This research highlights the dissemination of resistance in UPEC in Tanta, Egypt. The evident correlation between biofilm and resistance suggests a resistance cost on bacterial cells; and that isolates with lower resistance may rely on biofilms to enhance their survival. This emphasizes the importance of considering biofilm formation ability during the treatment of UPEC infections to avoid therapeutic failure and/or infection recurrence.

Bilateral maculopathy in a thalassemia patient on iron chelation therapy: a case report / Maculopatia bilateral em paciente com talassemia em terapia quelante de ferro: relato de caso

ABSTRACT A 10-year-old Malay girl with underlying HbE/beta-thalassemia, on regular blood transfusion and deferoxamine iron chelation therapy, presented with two-month history of bilateral blurring of vision. On examination, her vision was 6/36 both eyes. Other optic nerve functions were normal. Anterior segment examination of both eyes was unremarkable. Fundus examination of both eyes revealed dull foveal reflex. Optical coherence tomography of both maculae showed increased central subfield thickness. Fundus fluorescence angiography showed patchy hypofluorescence over macular region for both eyes and late staining, indicating retinal pigment epithelium anomalies. A diagnosis of iron-chelation-therapy-related bilateral maculopathy was made. Patient was co-managed with pediatric hematology team to adjust the dose of deferoxamine, and was given three monthly appointments to monitor the progression of maculopathy at the ophthalmology clinic. However patient defaulted ophthalmology follow-up after the first visit.

RESUMO Uma menina malaia de 10 anos de idade com doença de base- B/beta-talassemia, em transfusão de sangue regular e terapia quelante de ferro deferoxamina, apresentou história de dois meses de visão turva bilateral. Ao exame, sua visão era de 6/36 em ambos os olhos. Outras funções do nervo óptico estavam normais. O exame do segmento anterior de ambos os olhos foi normal. Exame do fundo de ambos os olhos revelou reflexo foveal opaco. A tomografia de coerência óptica de ambas as máculas mostrou aumento da espessura do subcampo central. A angiografia de fluorescência do fundo mostrou hipofluorescência irregular sobre a região macular de ambos os olhos e coloração tardia, indicando anomalias de epitélio pigmentar da retina. Um diagnóstico de maculopatia bilateral relacionada à terapia quelante de ferro foi feito. A paciente foi avaliada em conjunto com a equipe de hematologia pediátrica para ajustar a dose de deferoxamina, e foram oferecidas três consultas mensais na clínica oftalmológica, para monitorar a progressão da maculopatia. No entanto, ela não compareceu para acompanhamento oftalmológico após a primeira visita.

Comparison of contrast sensitivity in Beta-thalassemia patients treated by deferoxamine or deferasirox / Comparación de la sensibilidad de contraste en los pacientes con Beta-Talasemia tratados con Deferoxamina o Deferasirox

Purpose: To compare contrast sensitivity (CS) in multi-transfused β-thalassemia patients who received deferoxamine with those who received Osveral. Methods: In this cross sectional study a total of 60 Beta-thalassemia patients (30 used deferoxamine and 30 used deferasirox) were regarded as case group and 30 age and sex matched healthy subjects were selected as control group. All subjects had a set of examinations including refraction, visual acuity, Biomicroscopy, ophthalmoscopy and CS. Contrast threshold was assessed with the use of Freiberg visual acuity and contrast test under the mesopic light condition for three frequencies; 1, 5, 15cpd. All data analysis was performed using SPSS, version 17. Results: In visual acuity tests, thalassemic patients did not have any problem. Contrast threshold was higher in thalassemic patients who infuse deferoxamine (1.87 ± 0.63, 1.46 ± 0.81, and 2.96 ± 1.68 in 1, 5, and 15 cpd, respectively) than that of those who intake deferasirox (1.74 ± 0.80 (P = 0.743), 0.99 ± 0.74 (P = 0.047), and 2.42 ± 1.36 (P = 0.321) for 1, 5, and 15cpd, respectively), and also than healthy patients (1.33 ± 0.58 (P = 0.009), 0.95 ± 0.68 (P = 0.022), and 2.24 ± 1.23 (P = 0.135) for 1, 5, and 15cpd, respectively). Comparing those who used deferasirox with healthy subjects, contrast threshold was higher in deferasirox group at all special frequencies (P > 0.05). No significant relationship was observed between CS values and duration of transfusion, serum ferritin concentration and dose of chelation therapy (P > 0.05). Conclusions: CS tests can detect visual disturbance in thalassemic patients before the impairment of visual acuity. It is suggested that CS tests be included in their regular eye examination

Objetivo: Comparar la sensibilidad de contraste (SC) en pacientes multitrasfundidos con Beta-talasemia y tratados con deferoxamina u Osveral. Métodos: En este estudio transversal, un total de 60 pacientes con Beta-talasemia (30 tratados con deferoxamina y 30 con deferasirox) fueron considerados como grupo de estudio, y 30 sujetos sanos pareados por edad y sexo fueron seleccionados como grupo control. A todos los sujetos se les realizó una serie de exámenes que incluyeron refracción, agudeza visual, biomicroscopía, oftalmoscopía y SC. El umbral de contraste se valoró mediante la prueba de agudeza visual y contraste de Freiberg, en condiciones de visión mesópica para tres frecuencias: 1, 5 y 15 cpd. Todos los análisis de los datos se realizaron utilizando SPSS, versión 17. Resultados: En las pruebas de agudeza visual los pacientes con talasemia no tuvieron ningún problema. El umbral de contraste fue superior en los pacientes con talasemia a quienes se infundió deferoxamina (1,87 ± 0,63, 1,46 ± 0,81 y 2,96 ± 1,68 en 1, 5 y 15 cpd, respectivamente) que en los pacientes tratados con deferasirox (1,74 ± 0,8 (P = 0,743), 0,99 ± 0,74 (P = 0,047) y 2,42 ± 1,36 (P = 0,321) para 1, 5 y 15 cpd, respectivamente), y también en los pacientes sanos (1,33 ± 0,58 (P = 0,009), 0,95 ± 0,68 (P = 0,022) y 2,24 ± 1,23 (P = 0,135) para 1, 5 y 15 cpd, respectivamente). Al comparar los pacientes tratados con deferasirox y los sujetos sanos, el umbral de contraste fue superior en el grupo de deferasirox para todas las frecuencias especiales (P > 0,05). No se observó una relación significativa entre los valores de SC y la duración de la trasfusión, la concentración de ferritina sérica y la dosis de la terapia de quelación (P > 0,05). Conclusiones: Las pruebas de SC pueden detectar la alteración visual en los pacientes con talasemia con anterioridad al deterioro de la agudeza visual. Sugerimos la inclusión de las pruebas de SC en su examen ocular regular

Sobrecarga de ferro em adolescente com xerocitose: a importância da ressonância nuclear magnética / Iron overload in a teenager with xerocytosis: the importance of nuclear magnetic resonance imaging

Relatar um caso de sobrecarga de ferro secundária à xerocitose, uma doença rara, em uma adolescente, diagnosticada por meio de ressonância magnética em T2*. Relatamos o caso de uma paciente sintomática com xerocitose, nível de ferritina de 350ng/mL e sobrecarga de ferro cardíaca significativa. Ela foi diagnosticada por ressonância magnética em T2* e recebeu terapia de quelação. Análise por ectacitometria confirmou o diagnóstico de xerocitose hereditária. Na sequência, a ressonância magnética em T2* demonstrou resolução completa da sobrecarga de ferro em vários órgãos e novo ecocardiograma revelou resolução completa das alterações cardíacas anteriores. A paciente permanece em terapia de quelação. Xerocitose é uma desordem genética autossômica dominante rara, caracterizada por estomatocitose desidratada. O paciente pode apresentar fadiga intensa e sobrecarga de ferro. Sugerimos o uso regular de ressonância magnética em T2* para o diagnóstico e controle da resposta à quelação de ferro em xerocitose e acreditamos que o exame pode ser útil também em outras anemias hemolíticas que necessitam de transfusões.

To report a case of iron overload secondary to xerocytosis, a rare disease in a teenager, diagnosed, by T2* magnetic resonance imaging. We report the case of a symptomatic patient with xerocytosis, a ferritin level of 350ng/mL and a significant cardiac iron overload. She was diagnosed by T2* magnetic resonance imaging and received chelation therapy Ektacytometric analysis confirmed the diagnosis of hereditary xerocytosis. Subsequent T2* magnetic resonance imaging demonstrated complete resolution of the iron overload in various organs, as a new echocardiography revealed a complete resolution of previous cardiac alterations. The patient remains in chelation therapy. Xerocytosis is a rare autosomal dominant genetic disorder characterized by dehydrated stomatocytosis. The patient may present with intense fatigue and iron overload. We suggest the regular use of T2* magnetic resonance imaging for the diagnosis and control of the response to iron chelation in xerocytosis, and we believe it can be used also in other hemolytic anemia requiring transfusions.

Chelation therapy with desferrioxamine does not normalize ferritin level but attenuates oxidative damage and improves total antioxidant level in malaysian Chinese β-thalassaemia major patients / La terapia de quelación con deferoxamina no normaliza los niveles de ferritinaa pero atenúa el daño oxidativo y mejora el nivel antioxidante total en los pacientes sinomalayos que padecen de talasemia β

Beta-thalassaemia major causes severe anaemia and patients with it may be transfusion-dependent for life. Regular blood transfusions cause iron-overload that leads to oxidative damage which can hasten mortality. The objective of this research was to study the oxidant-antioxidant indices in β-thalassaemia major patients at the University of Malaya Medical Centre (UMMC) who were on desferrioxaminechelation or without chelation therapy. Blood was collected from 39 Chinese patients and 20 controls. Plasma and peripheral blood mononuclear cell lysates (PBMC) were extracted and biochemical tests to evaluate oxidative stress were performed. Oxidative stress was evident in these patients as advanced oxidized protein products (AOPP) and lipid hydroperoxides were elevated, whereas glutathione peroxidase activity and the ferric reducing antioxidant power (FRAP) were reduced. The catalase activity in the patients' PBMC was elevated, possibly as a compensatory mechanism for the reduced glutathione peroxidase activity in both red blood cells and PBMC. The lower FRAP and higher AOPP levels in the non-chelated patients compared with the chelated patients were indicative of a lower oxidative stress level in the chelated patients. The ferritin levels in the chelated and non-chelated patients were high and the mean levels of liver enzyme activities in the majority of patients were elevated regardless of chelation therapy. In conclusion, this study indicates that desferrioxamine chelation therapy does not normalize ferritin level but attenuates oxidative damage and improves total antioxidant level in Malaysian Chinese β-thalassaemia major patients.

La beta-talasemia mayor causa anemia severa, y los pacientes con este padecimiento pueden hacerse dependientes de las transfusiones de sangre por el resto de sus vidas. Las transfusiones regulares de sangre dan lugar a una sobrecarga de hierro que conduce al dano oxidativo, el cual a su vez puede acelerar la mortalidad. El objetivo de esta investigación fue estudiar las tasas de oxidantesantioxidantes en pacientes de beta-talasemia mayor en el Centro Médico de la Universidad de Malaya, tanto aquellos bajo tratamiento de quelación con deferoxamina, como aquellos sin terapia de quelación alguna. Se recogieron muestras de sangre de 39 pacientes chinos y 20 controles. Se extrajeron plasma y lisados de celulas mononucleares perifericas (CMSP), y se realizaron pruebas bioquimicas para evaluar el estrés oxidativo. El estrés oxidativo era evidente en estos pacientes en forma de productos avanzados de oxidación de proteinas (PAOP), y los hidroperoxidos de lipidos eran elevados, en tanto que la actividad de glutatión peroxidasa y el poder reductor ferrico/antioxidante (FRAP) era reducida. La actividad de la catalasa en los pacientes de CMSP era elevada, posiblemente como un mecanismo compensatorio frente a la actividad de glutatión peroxidasa reducida tanto en los globulos rojos como en las CMSP. Los niveles más bajos de FRAP y los más altos de PAOP en los pacientes no quelados en comparación con los pacientes quelados, indicaban un bajo nivel de estrés oxidativo en los pacientes quelados. Los niveles de ferritina tanto en los pacientes quelados como en los no quelados, eran altos, y los niveles promedio de actividades enzimaticas del higado fueron elevados en la mayoria de los pacientes, independientemente de la terapia de quelación. En conclusión, este estudio indica que la terapia de quelación con deferoxamina no normaliza el nivel de ferritina, pero en cambio atenua el daño oxidativo, y mejora el nivel antioxidante total en los pacientes sinomalayos afectados por la betatalasemia mayor.

Stroke in patients with sickle cell disease: clinical and neurological aspects

The aim of this study was to characterize a group of patients (n=8) with sickle cell disease (SCD) and ischemic stroke concerning the clinical, neurological, imaging and progressive aspects. Data were collected from records and completed with an interview of patients and their parents. In this study there were 8 patients with ages ranging from 10 to 23 years old; SCD diagnosis was given between one and two years of age with clinical features of fatigue and anemia. The stroke was ischemic in all individuals and the first cerebrovascular event occurred before 6 years of age; 3 patients had recurrence of stroke despite prophylactic blood transfusion therapy and both cerebral hemispheres were affected in 4 patients. Clinical and neurological current features observed were: acute pain crises, sialorrhea, mouth breathing, motor, and neuropsychological impairments resulting from cortical-subcortical structure lesions.

O objetivo deste estudo foi caracterizar um grupo de sujeitos (n=8) com antecedentes de anemia falciforme (AF) e acidente vascular cerebral (AVC) isquêmico, dos pontos de vista clínico, neurológico, radiológico e evolutivo, reavaliados através de exame neurológico e neuropsicológico. A partir de prontuários dos sujeitos com diagnóstico comprovado de AF e AVC, coletamos dados, complementados por entrevista com pacientes e responsáveis. Foram avaliados 8 pacientes; atualmente com idades entre 10 e 23 anos; diagnóstico da AF entre um e dois anos; quadro clínico de fraqueza e anemia. Em todos, o AVC foi isquêmico e o primeiro evento na maioria ocorreu antes dos 6 anos de idade; houve recorrência do AVC em 3, apesar da profilaxia com transfusão sanguínea; ambos os hemisférios afetados em 4; no quadro clínico e neurológico atual constatamos crises dolorosas, sialorréia, respiração oral e importante comprometimento motor e neuropsicológico, resultantes de lesões estruturais cortico-subcorticais.