The anticancer activity of bovine lactoferrin is reduced by deglycosylation and it follows a different pathway in cervix and colon cancer cells.

Bovine lactoferrin (bLF) is a glycosylated protein with purported beneficial properties. The aim of this work was to determine the role of bLF glycosylation in the adhesion, internalization, and growth inhibition of cancer cells. The viability of cervix (HeLa) and colon (Caco-2) cancer cells (MTT assay and epifluorescence microscopy) was inhibited by bLF, while deglycosylated bLF (bLFdeg) had no effect. Adhesion to cell surfaces was quantified by immunofluorescence assay and showed that bLF was able to bind more efficiently to both cell lines than bLFdeg. Microscopic observations indicated that bLF glycosylation favored bLF binding to epithelial cells and that it was endocytosed through caveolin-1-mediated internalization. In addition, the mechanism of action of bLF on cancer cell proliferation was investigated by determining the amount of phosphorylated intermediates of signaling pathways such as epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK) and protein kinase B (known as Akt). Chemoluminescence immunoassay of phosphorylated intermediates showed that bLF inhibited Akt phosphorylation, consistent with its growth inhibiting activity. This assay also indicated that the bLF receptor/signaling pathways may be different in the two cell lines, Caco-2 and HeLa. This work confirmed the effect of glycosylated bLF in inhibiting cancer cell growth and that glycosylation is required for optimal surface adhesion, internalization, and inhibition of the ERK/Akt pathway of cell proliferation through glycosylated cell surface receptors.

Maxillary mucormycosis and aspergillosis in post-COVID-19 patients in Mexico: A case series.

BACKGROUND: Fungal infections, during or as a consequence of SARS-CoV-2 infection, associated with uncontrolled diabetes mellitus and indiscriminate use of corticosteroids have been reported. In the jaw, mostly mucormycosis has been diagnosed in hospitals. METHODS: A retrospective, cross-sectional, descriptive study of the clinical, imaging, and histopathologic characteristics of maxillary invasive fungal infection in post-COVID-19 patients diagnosed in a private non-hospital oral pathology service in Mexico during 2020-2022 was conducted. RESULTS: We found 20 cases of maxillary invasive fungal infections in post-COVID-19 patients, 75% including a diagnosis of mucormycosis and 25% diagnosed as probable aspergillosis. The most common signs and symptoms were exposed necrotic bone followed by tooth mobility, discharge, and pain. On imaging, unilateral maxillary sinus involvement was observed in 6 cases (30%), and bilateral maxillary sinus involvement was observed in 3 cases (15%). CONCLUSIONS: It is essential to consider the association of osteonecrosis of the jaw in post-COVID-19 patients, with aspergillosis, not only mucormycosis, for early diagnosis and appropriate treatment.

Incidencia del espectro de acretismo placentario en la unidad de cuidados intensivos obstétricos del Hospital de la Mujer de Sinaloa / Incidence of the placental accretism spectrum in the obstetric intensive care unit of the Hospital de la Mujer of Sinaloa

Resumen OBJETIVO: Determinar la incidencia del espectro del acretismo placentario en pacientes ingresadas a la unidad de cuidados intensivos obstétricos del Hospital de la Mujer, Culiacán, Sinaloa. MATERIALES Y MÉTODOS: Estudio retrospectivo, transversal y descriptivo fundamentado en el análisis de la base de datos del Hospital de la Mujer de pacientes internadas entre los años 2017 a 2020 con diagnóstico de espectro de placenta acreta, referidas o diagnosticadas en la institución e intervenidas para histerectomía por la complicación estudiada. RESULTADOS: Se analizaron 22 pacientes con diagnóstico de acretismo placentario que dieron una incidencia de 0.09%; de éstas, a 1 se le indicó cesárea; 19 de las 22 pacientes tenían antecedente de cicatriz uterina previa, todas con placenta previa. El promedio de edad fue de 30.86 ± 4 años. La cesárea se practicó, en promedio, a las 34 semanas de embarazo con dos técnicas quirúrgicas. El sangrado promedio estimado fue de 1.947 mL. Las complicaciones transoperatorias fueron las lesiones: ureteral (n = 2) y vesical (n = 1). La principal complicación posoperatoria fue la fístula vesicouterina (n = 1). El promedio de estancia fue de 2 días en 16 de las 22 pacientes y de 7 días en las 6 restantes. CONCLUSIONES: Lo importante del acretismo placentario es el diagnóstico oportuno que permita derivar a las pacientes a centros hospitalarios que cuenten con especialistas experimentados en la atención de estos casos.

Abstract OBJECTIVE: To determine the incidence of placental accretism spectrum in pregnant women admitted to the obstetric intensive care unit of the Hospital de la Mujer, Culiacán, Sinaloa. MATERIALS AND METHODS: Retrospective, cross-sectional, descriptive study based on the analysis of the database of the Hospital de la Mujer of patients admitted between 2017 and 2020 with a diagnosis of placenta accreta spectrum, referred or diagnosed at the institution and underwent hysterectomy for the complication studied. RESULTS: Twenty-two patients with a diagnosis of placenta accreta were analysed, giving a prevalence of 0.09%; of these, caesarean section was indicated in 0.2%. 19 of the 22 patients had a history of previous uterine scarring, all with placenta praevia. Mean age was 30.86 ± 4 years. Caesarean section was performed at a mean gestational age of 34 weeks using two surgical techniques. The mean estimated blood loss was 1,947 mL. The most common operative complications were ureteral (n = 2) and bladder (n = 1) injuries. The most common postoperative complication was vesico-uterine fistula (n = 1). The mean length of stay was 2 days in 16 of the 22 patients and 7 days in the remaining 6 patients. CONCLUSIONS: The most important aspect of placenta accreta is early diagnosis, which allows referral to hospital centres with specialists experienced in the management of these cases.

Unusual Manifestation of Membranous Dysmenorrhea: Case Report.

BACKGROUND In the 18th century, Morgagni described membranous dysmenorrhea as the sudden and complete detachment of the decidua during menstruation. This causes intense and painful contractions of the myometrium, aggravated by the expulsion of tissues produced by the decidualization of the endometrium. It is a rare pathology associated with oral contraceptives, ectopic pregnancies, abortions, and natural cycles, with consequent thickening and endometrial decidualization with molding of the tissue of the uterine cavity of membranous appearance. The definitive diagnosis is made by histopathological examination. CASE REPORT A 43-year-old female patient came for urgent consultation for an acute picture of severe pain in the lower abdomen, radiating to the genital area with transvaginal bleeding of 2 h of evolution. She had no significant past medical history. A transvaginal ultrasound was performed and showed an unchanged endometrial cavity. A vaginal examination revealed a foreign body of soft consistency; therefore, a speculum examination was performed, which showed tissue of endometrial origin located in the cervical canal of a reddish spongy texture. The tissue was removed, thus improving the symptomatology, and was sent to the pathological anatomy service for histopathologic diagnosis. CONCLUSIONS Membranous dysmenorrhea is a rare gynecologic disorder with only a few documented cases. According to other case reports, our patient's case, at age 43 years, was an atypical presentation. The clinical features and association with this pathology allowed the diagnosis and its confirmation by histopathological examination.

Stem-Loop Structures in Iron-Regulated mRNAs of Giardia duodenalis.

Giardia duodenalis is a significant cause of waterborne and foodborne infections, day-care center outbreaks, and traveler's diarrhea worldwide. In protozoa such as Trichomonas vaginalis and Entamoeba histolytica, iron affects the growth, pathogenicity mechanisms, and expression of virulence genes. One of the proposed iron regulatory mechanisms is at the post-transcriptional level through an IRE/IRP-like (iron responsive element/iron regulatory protein) system. Recently, the expression of many putative giardial virulence factors in the free-iron levels has been reported in subsequent RNAseq experiments; however, the iron regulatory mechanism remains unknown. Thus, this work aimed to determine the effects of iron on the growth, gene expression, and presence of IRE-like structures in G. duodenalis. First, the parasite's growth kinetics at different iron concentrations were studied, and the cell viability was determined. It was observed that the parasite can adapt to an iron range from 7.7 to 500 µM; however, in conditions without iron, it is unable to survive in the culture medium. Additionally, the iron modulation of three genes was determined by RT-PCR assays. The results suggested that Actin, glucosamine-6-phosphate deaminase, and cytochrome b5 mRNA were down-regulated by iron. To investigate the presence of IRE-like structures, in silico analyses were performed for different mRNAs from the Giardia genome database. The Zuker mfold v2.4 web server and theoretical analysis were used to predict the secondary structures of the 91 mRNAs analyzed. Interestingly, the iron-induced downregulation of the genes analyzed corresponds to the location of the stem-loop structures found in their UTR regions. In conclusion, iron modulates the growth and expression of specific genes, likely due to the presence of IRE-like structures in G. duodenalis mRNAs.

Antitumor activity of bovine lactoferrin and its derived peptides against HepG2 liver cancer cells and Jurkat leukemia cells.

Liver cancer and leukemia are the fourth and first causes, respectively, of cancer death in children and adults worldwide. Moreover, cancer treatments, although beneficial, remain expensive, invasive, toxic, and affect the patient's quality of life. Therefore, new anticancer agents are needed to improve existing agents. Because bovine lactoferrin (bLF) and its derived peptides have antitumor properties, we investigated the anticancer effect of bLF and LF peptides (LFcin17-30, LFampin265-284 and LFchimera) on liver cancer HepG2 cells and leukemia Jurkat cells. HepG2 and Jurkat cells were incubated with bLF and LF peptides. Cell proliferation was quantified by an MTT assay, and cell morphology and damage were visualized by light microscopy or by phalloidin-TRITC/DAPI staining. The discrimination between apoptosis/necrosis was performed by staining with Annexin V-Alexa Fluor 488 and propidium iodide, and the expression of genes related to apoptosis was analyzed in Jurkat cells. Finally, the synergistic interaction of bLF and LF peptides with cisplatin or etoposide was assessed by an MTT assay and the combination index. The present study demonstrated that bLF and LF peptides inhibited the viability of HepG2 and Jurkat cells, inducing damage to the cell monolayer of HepG2 cells and morphological changes in both cell lines. bLF, LFcin17-30, and LFampin265-284 triggered apoptosis in both cell lines, whereas LFchimera induced necrosis. These results suggested that bLF and LF peptides activate apoptosis by increasing the expression of genes of the intrinsic pathway. Additionally, bLF and LF peptides synergistically interacted with cisplatin and etoposide. In conclusion, bLF and LF peptides display anticancer activity against liver cancer and leukemia cells, representing an alternative or improvement in cancer treatment.

Epidemiological and clinical characteristics of pregnant women and neonates with COVID-19 in Northwest Mexico.

INTRODUCTION: The SARS-CoV-2 virus, which causes COVID-19, has spread quickly worldwide, causing millions of cases and thousands of deaths. Some risk factors in the general population are related to the development of severe COVID-19 or death, but in pregnant women and neonates, the information is limited. OBJECTIVE: To determine the epidemiological and clinical characteristics of pregnant women and neonates diagnosed with COVID-19 by RT-PCR and serological tests, and analyze the relationship between the influenza vaccination and COVID-19 symptoms in infected pregnant women in Sinaloa state. METHODS: We collected samples from 116 pregnant women and 84 neonates from the Women´s Hospital of Sinaloa. They were diagnosed with COVID-19 by RT-PCR and serological tests (IgG), and sociodemographic, clinical and laboratory parameters were recorded. RESULTS: A total of 11.2% (13/116) of the pregnant women were RT-PCR+, 25% (29/116) were IgG+ and 4.3% (5/116) were positive for both tests. Symptoms such as rhinorrhea (P = .04), cough (P = .02) and polypnea (P = .04) in pregnant women were related to COVID-19, also leukocyte index was higher in pregnant women with COVID-19 (P = .03), but the associations were lost after the Bonferroni correction. No laboratory parameters or underlying diseases were associated with COVID-19, and most infected pregnant women had mild cases. We found an association between the influenza vaccine and less common COVID-19 symptoms in pregnant women who were infected (P = .01). A total of 7.2% (6/84) of neonates were RT-PCR+, 35.7% (30/84) were IgG+, and there were no symptoms or underlying diseases associated with neonates who were infected. In conclusion, this work demonstrated that some symptoms were related to COVID-19, most pregnant women and neonates had mild cases, and the influenza vaccine could decrease the severity of COVID-19 cases in pregnant women.

Prevalence of Cyclomodulin-Positive E. coli and Klebsiella spp. Strains in Mexican Patients with Colon Diseases and Antimicrobial Resistance.

Colon diseases, such as colorectal cancer (CRC), are multifactor diseases that affect more than one million people per year; recently, the microbiota has been associated with an etiologic factor, specifically bacterial cyclomodulin positivity (CM+). Unfortunately, there are no studies from Mexico that detail the presence of bacterial CM+ in patients with colon diseases. We therefore performed a comprehensive study to investigate the associations and prevalence of cyclomodulin-positive Diarrheagenic E. coli (DEC), non-DEC, and Klebsiella spp. strains isolated from Mexican subjects with colon diseases. In this work, we analyzed 43 biopsies, 87 different bacteria were isolated, and E. coli was the most frequently noted, followed by Klebsiella spp., and Enterococcus spp. E. coli, non-DEC, and EPEC belonging to phylogroup B2 were the most prevalent. More than 80% of E. coli and Klebsiella were CM+. pks, cdt, cnf, and cif were identified. cdt was associated with non-DEC, cif and its combinations with EPEC, as well as cdt and psk with Klebsiella. Lastly, all the CM+ bacteria were resistant to at least one antibiotic (34% were MDR, and 48% XDR). In conclusion, the high prevalence of bacterial CM+ in colon disease patients suggests that these bacteria play an important role in the genesis of these diseases.

Bovine lactoferrin and lactoferrin peptides affect endometrial and cervical cancer cell lines.

Cervical, uterine, and ovarian cancers are the most common malignancies of the female genital tract worldwide. Despite advances in prevention, early diagnosis, effective screening, and treatment programs, mortality remains high. Consequently, it is important to search for new treatments. The activity of bovine lactoferrin (bLF) and LF peptides against several types of cancer has been studied; however, only a few studies report the effect of bLF and LF peptides against cervical and endometrial cancers. In this study, we explored the effect of bLF as well as LF chimera and its constituent peptides LFcin17-30 and LFampin265-284 on the viability of cervical (HeLa, SiHa) and endometrial (KLE, HEC-1A) cancer cell lines. Cell proliferation was quantified with an MTT assay, cell morphological changes and damage were determined by Giemsa and phalloidin-TRITC and DAPI staining, and apoptotic and necrotic cells were identified by Alexa Fluor® 488 Annexin V and propidium iodide staining. Additionally, the effect of combinations of bLF and LF peptides with cisplatin was assessed. bLF and LF peptides inhibited the proliferation of uterine cancer cells and caused cellular morphological changes and damage to cell monolayers. bLF induced apoptosis, LFcin17-30 and LFampin265-284 induced apoptosis and necrosis, and LF chimera induced necrosis. Additionally, bLF and LF chimera showed an additive interaction with cisplatin against uterine cancer cells.

[Unilateral congenital pulmonary lymphangiectasia in a preterm infant]. / Linfangiectasia pulmonar congénita unilateral en un neonato prematuro.

Unilateral congenital pulmonary lymphangiectasia (CPL) is an extremely rare disease of the pulmo nary lymphatic vessels. OBJECTIVE: to present a case of CPL in a premature newborn. CLINICAL CASE: premature male newborn with severe respiratory failure at 2 hours of extrauterine life was treated with exogenous surfactant, catecholamines and high frequency oscillatory ventilation (HFOV). Chest computed tomography (CT) scan showed bullae and air trapping of the left lung; the histopathological study showed cystic dilation of the bronchoalveolar lymphatic channels. The diagnosis of secondary unilateral CPL was made. The clinical course up to 19 months of age was normal and the chest CT scan showed few emphysematous bullae. CONCLUSIONS: CPL must be one of the differential diagnoses in neonates with unexplained respiratory distress. The prognosis will depend on the type of CPL and lung involvement.

Linfangiectasia pulmonar congénita unilateral en un neonato prematuro / Unilateral congenital pulmonary lymphangiectasia in a preterm infant

La linfangiectasia pulmonar congénita (LPC) unilateral es una enfermedad extremadamente rara de los vasos linfáticos pulmonares. OBJETIVO: presentar un caso de LPC en un recién nacido prematuro. CASO CLÍNICO: recién nacido masculino, prematuro, con insuficiencia respiratoria severa a las 2 horas de vida extrauterina, recibió tratamiento con surfactante exógeno, catecolaminas y ventilación de alta frecuencia oscilatoria (VAFO). La tomografía axial computarizada (TAC) de tórax reveló bulas y atrapamiento de aire de pulmón izquierdo, el estudio histopatológico describió dilatación quística de los canales linfáticos broncoalveolares. Se diagnosticó LPC unilateral secundaria. La evolución clínica hasta los 19 meses de edad fue normal y la TAC de tórax mostró escasas bulas enfisematosas. CONCLUSIONES: La LPC debe ser uno de los diagnósticos diferenciales en neonatos con dificultad respiratoria inexplicable. El pronóstico dependerá del tipo de LPC y de la afectación pulmonar.

Unilateral congenital pulmonary lymphangiectasia (CPL) is an extremely rare disease of the pulmo nary lymphatic vessels. OBJECTIVE: to present a case of CPL in a premature newborn. CLINICAL CASE: premature male newborn with severe respiratory failure at 2 hours of extrauterine life was treated with exogenous surfactant, catecholamines and high frequency oscillatory ventilation (HFOV). Chest computed tomography (CT) scan showed bullae and air trapping of the left lung; the histopathological study showed cystic dilation of the bronchoalveolar lymphatic channels. The diagnosis of secondary unilateral CPL was made. The clinical course up to 19 months of age was normal and the chest CT scan showed few emphysematous bullae. CONCLUSIONS: CPL must be one of the differential diagnoses in neonates with unexplained respiratory distress. The prognosis will depend on the type of CPL and lung involvement.

Maternal Risk Factors Associated with the Development of Cleft Lip and Cleft Palate in Mexico: A Case-Control Study.

INTRODUCTION: Cleft lip and palate, the most common developmental deformity, is seen worldwide and the etiology involves a combination of genetic and environmental factors. The purpose of this study was to determine the maternal risk factors associated with the development of cleft lip and cleft palate. MATERIALS AND METHODS: We conducted a case control study at the Women's Hospital in Culiacan, Mexico. Medical records were analyzed, including patients who delivered babies with and without cleft lip and cleft palate from January 2010 to December 2015. Multiple variables were analyzed, including gestational age, weight at birth, the use of folic acid and multivitamins during pregnancy, smoking, alcohol abuse, the use of recreational drugs, history of sexually transmitted infections, marital status, socioeconomic status, education, and nutritional status. RESULTS: We found that the maternal risk factors with the strongest association for the development of cleft lip and cleft palate were the following: patients who were not taking folic acid during pregnancy [OR 3.27, 95% CI 1.32-8.09], P=0.00; patients who were not taking vitamin supplementation during pregnancy [OR 2.6, 95% CI 1.19-7.27], P=0.02; smoking during pregnancy [OR 2.05, 95% CI 1.23-3.41], P=0.01; and alcohol abuse during pregnancy [OR 1.90, 95% CI 1.17-3.08], P=0.03. CONCLUSIONS: The main risk factors associated with the development of cleft lip and cleft palate in a Mexican population at the Women's hospital in Culiacan, Sinaloa, Mexico were smoking, alcohol abuse, and patients not taking folic acid and multivitamins during pregnancy.

Balance de líquidos y lesión renal aguda en el choque séptico / Fluid balance and acute kidney injury in septic shock

Resumen: Introducción: En el paciente con choque séptico, la administración excesiva de líquidos puede incrementar la morbilidad y mortalidad. El objetivo de este estudio fue evaluar la asociación entre el balance de líquidos, la lesión renal aguda y la mortalidad en pacientes con choque séptico. Métodos: Se realizó un estudio de casos y controles en una unidad de terapia intensiva pediátrica. Se comparó el balance de líquidos en las primeras 72 h y la presencia de lesión renal aguda en pacientes con diagnóstico de choque séptico que fallecieron contra pacientes que sobrevivieron a la misma patología. Se realizó un análisis univariado y multivariado. Resultados: Se incluyeron 45 casos y 45 controles en el análisis. La mortalidad se asoció con riesgo pediátrico de mortalidad (PRISM) ≥ 26 puntos (RM 7.5, IC 95% 2.8-18.7; p = 0.000), disfunción orgánica logística pediátrica (PELOD) ≥ 24 puntos (RM 11.0, IC 95% 4.1-29.4; p = 0.000), creatinina ≥ 0.65 mg/dl (RM 5.6, IC 95% 2.2-13.9; p = 0.000), lactato ≥ 2.5 mmol/l (RM 2.5, IC 95% 1.1-5.9; p = 0.033), SvO2 < 60% (RM 4.6, IC 95% 4.5-4.5; p = 0.001), balance positivo > 9% en 72 h (RM 4.3, IC 95% 1.6-11.7; p = 0.003), lesión renal aguda (RM 5.7, IC 95% 2.2-15.1; p = 0.000). En el modelo multivariado, PRISM ≥ 26 y PELOD ≥ 24 puntos permanecieron significativas. Conclusiones: En los pacientes que fallecieron por choque séptico, el modelo multivariado mostró una asociación con PRISM ≥26 y PELOD ≥24 y una tendencia hacia la asociación con SvO2 <60% y balance de líquidos positivo >9%.

Abstract: Background: In patients with septic shock, excessive fluid administration can lead to increased morbidity and mortality. The aim of this study was to evaluate the association between fluid balance, acute kidney injury and mortality in patients with septic shock. Methods: A study of cases and controls was conducted in a Pediatric Intensive Care Unit. The fluid balance in the first 72 h and the presence of acute kidney injury was compared in patients diagnosed with septic shock who died against patients who survived the same condition. Univariate and multivariate analyses were performed. Results: Forty-five cases and forty-five controls were included in the analysis. Mortality was associated with Pediatric Risk of Mortality (PRISM III) ≥ 26 points (OR 7.5, 95% CI 2.8-18.7; p = 0.000), Pediatric Logistic Organ Dysfunction (PELOD) ≥ 24 points (OR 11.0, 95% CI 4.1-29.4; p = 0.000), creatinine ≥ 0.65 mg/dl (OR 5.6, 95% CI 2.2-13.9; p = 0.000), lactate ≥ 2.5 mmol/l (OR 2.5, 95% CI 1.1-5.9; p = 0.033), SvO2 < 60% (OR 4.6, 95% CI 4.5-4.5; p = 0.001), positive balance > 9% in 72 h (OR 4.3, 95% CI 1.6-11.7; p = 0.003), acute kidney injury (OR 5.7, 95% CI: 2.2-15.1; p = 0.000). In the multivariate model, the values of PRISM ≥26 and PELOD ≥24 points were significant. Conclusions: In patients who died due to septic shock, the multivariate model showed an association with PRISM ≥26 and PELOD ≥24 and a trend toward association with SvO2 <60% and positive balance of liquids > 9%.

Strategies of Vibrio parahaemolyticus to acquire nutritional iron during host colonization.

Iron is an essential element for the growth and development of virtually all living organisms. As iron acquisition is critical for the pathogenesis, a host defense strategy during infection is to sequester iron to restrict the growth of invading pathogens. To counteract this strategy, bacteria such as Vibrio parahaemolyticus have adapted to such an environment by developing mechanisms to obtain iron from human hosts. This review focuses on the multiple strategies employed by V. parahaemolyticus to obtain nutritional iron from host sources. In these strategies are included the use of siderophores and xenosiderophores, proteases and iron-protein receptor. The host sources used by V. parahaemolyticus are the iron-containing proteins transferrin, hemoglobin, and hemin. The implications of iron acquisition systems in the virulence of V. parahaemolyticus are also discussed.

Strategies of Intracellular Pathogens for Obtaining Iron from the Environment.

Most microorganisms are destroyed by the host tissues through processes that usually involve phagocytosis and lysosomal disruption. However, some organisms, called intracellular pathogens, are capable of avoiding destruction by growing inside macrophages or other cells. During infection with intracellular pathogenic microorganisms, the element iron is required by both the host cell and the pathogen that inhabits the host cell. This minireview focuses on how intracellular pathogens use multiple strategies to obtain nutritional iron from the intracellular environment in order to use this element for replication. Additionally, the implications of these mechanisms for iron acquisition in the pathogen-host relationship are discussed.

Bactericidal effect of bovine lactoferrin, LFcin, LFampin and LFchimera on antibiotic-resistant Staphylococcus aureus and Escherichia coli.

Increased prevalence of antibiotic-resistant bacteria has become a major threat to the health sector worldwide due to their virulence, limited therapeutic options and distribution in both hospital and community settings. Discovery and development of new agents to combat antibiotic-resistant bacteria is thus needed. This study therefore aimed to evaluate the ability of bovine lactoferrin (LF), peptides from two antimicrobial domains lactoferricin B (LFcin17-30) and lactoferrampin (LFampin265-284) and a chimeric construct (LFchimera) containing both peptides, as potential bactericidal agents against clinical isolates of antibiotic-resistant Staphylococcus aureus and Escherichia coli. Results in kinetics of growth show that LF chimera and peptides inhibited the growth of both bacterial species. By confocal microscopy and flow cytometry it was observed that LF and FITC-labeled peptides are able to interact with these bacteria and cause membrane permeabilization, as monitored by propidium iodide staining, these effects were decreased by preincubation with lipopolysaccharide in E. coli. By electron microscopy, a clear cellular damage was observed in bacteria after treatments with LFchimera and peptides, suggesting that interaction and membrane disruption are probably involved as a mechanism of action. In conclusion, results show that LFchimera, LF and peptides have potential as bactericidal agents in the antibiotic-resistant strains of S. aureus and E. coli and also the work strongly suggest that LFcin17-30 and LFampin265-284 acts synergistically with antibiotics against multidrug resistant EPEC and MRSA in vitro.

Patogénesis molecular, epidemiología y diagnóstico de Escherichia coli enteropatógena / Molecular pathogenesis, epidemiology and diagnosis of enteropathogenic Escherichia coli

Escherichia coli enteropatógena (EPEC) es una de las principales causas de diarrea en niños menores de dos años en países en vías de desarrollo. La principal característica histopatológica de la infección es una lesión que induce la EPEC en el intestino conocida como la lesión A/E (adherencia y eliminación). Las bacterias se adhieren a los enterocitos y permiten la acumulación de la actina del citoesqueleto en la región apical de la célula, hasta formar una estructura de tipo "pedestal" y causar la eliminación de las microvellosidades intestinales. A pesar de que se conoce de modo detallado el proceso de formación de los pedestales de actina, aún no se ha esclarecido el mecanismo global de la diarrea que induce EPEC. La diarrea se ha vinculado con: a) la destrucción de las microvellosidades del enterocito, b) la salida masiva de iones hacia la luz intestinal y c) la secreción de alguna enterotoxina. En estudios realizados en países en vías de desarrollo se ha demostrado que EPEC es uno de los principales agentes participantes en la diarrea infantil, con elevadas tasas de morbilidad y mortalidad. El diagnóstico microbiológico de la infección se realiza con metodologías adicionales a las utilizadas con regularidad en el laboratorio de microbiología clínica, entre ellas las siguientes: a) serotipificación, b) ensayo de adherencia, c) prueba de FAS (tinción fluorescente para actina) y d) detección específica de genes que codifican a proteínas incluidas en la patogénesis, como el bfpA y eae. Un objetivo de esta revisión es actualizar los avances observados en la patogénesis molecular de la infección por EPEC, las metodologías para el diagnóstico microbiológico y la epidemiología en México y otros países en vías de desarrollo.

Enteropathogenic Escherichia coli (EPEC) is a leading cause of diarrhea in infants less than two years of age in developing countries. To induce diarrhea EPEC uses several virulence factors acting on a still unknown and mysterious mechanism. The hallmark of EPEC infection is a histological intestinal alteration known as the attaching and effacing (A/E) lesion. The bacterium attaches intimately to the enterocyte and induces assembly of cytoskeleton intracellular actin on the cellular surface. Rearrangements of the actin cytoskeleton form a pedestal-like structure where bacterium tightly cups the cells, leading to degeneration of brush border microvilli. Although the mechanism of EPEC-induced pedestal formation has been dissected in detail, the overall mechanism of diarrhea is still obscure. It is believed that EPEC-mediated secretory diarrhea is related to a) intestinal microvilli effacement, b) massive loss of intracellular ions into the intestinal milieu and c) secretion of an EPEC enterotoxin. Epidemiological studies conducted in developing countries have shown that EPEC is one of the main bacteria frequently isolated from children with diarrhea, causing high morbidity and mortality rates. The microbiological diagnosis of EPEC-induced disease is performed with analytic methodologies different from those used by the standard microbiology laboratory, the most relevant being: a) serotypification, b) the adherence assay, c) FAS test, and d) the specific detection of virulence-involved genes (bfpA and eae genes) using molecular biology techniques. The purpose of this review is to update the most recent findings regarding the molecular pathogenesis of EPEC, its epidemiology in Mexico as well as other developing countries, and also the developed methodology for the diagnosis of EPEC infection.

Intoxication of epithelial cells by plasmid-encoded toxin requires clathrin-mediated endocytosis.

It has been shown that the autotransporter plasmid-encoded toxin (Pet) of enteroaggregative Escherichia coli (EAEC) produces cytotoxic and enterotoxic effects. Both effects can be explained by the proteolytic activity of Pet on its intracellular target alpha-fodrin (alphaII spectrin). In addition, Pet cytotoxicity and enterotoxicity depend on Pet serine protease activity, and on its internalization into epithelial cells. However, the mechanisms of Pet uptake by epithelial cells are unknown. Here, we show that Pet interacts with the plasma membrane of epithelial cells, and afterwards is detected inside the cells. Furthermore, Pet was internalized via clathrin-mediated endocytosis, since its internalization was inhibited by monodansylcadaverine and sucrose, but not by filipin or methyl-beta-cyclodextrin, which are drugs that interfere with protein entry via a clathrin-independent pathway. Additionally, Pet was immunoprecipitated by anti-clathrin antibodies, but not by anti-caveolin antibodies. Moreover, small interfering RNA (siRNA), designed to knock out clathrin gene expression in HEp-2 cells, prevented Pet internalization, and thereby the Pet-induced cytotoxic effect. However, the use of siRNA to knock out caveolin expression had no effect on Pet internalization, and the cytotoxic effect was clearly observed. Together, these data indicate that Pet secreted by EAEC binds to the cell surface via an unknown receptor, to be taken up by clathrin-mediated endocytosis, and exert its toxic effect in the cytoplasm.

Pet, a non-AB toxin, is transported and translocated into epithelial cells by a retrograde trafficking pathway.

The plasmid-encoded toxin (Pet) of enteroaggregative Escherichia coli is a 104-kDa autotransporter protein that exhibits proteolytic activity against the actin-binding protein alpha-fodrin. Intracellular cleavage of epithelial fodrin by Pet disrupts the actin cytoskeleton, causing both cytotoxic and enterotoxic effects. Intoxication requires the serine protease activity of Pet and toxin endocytosis from clathrin-coated pits. The additional events in the intracellular trafficking of Pet are largely uncharacterized. Here, we determined by confocal microscopy that internalized Pet is transferred from the early endosomes to the Golgi apparatus and then travels to the endoplasmic reticulum (ER). Pet associates with the Sec61p translocon before it moves into the cytosol as an intact, 104-kDa protein. This translocation process contrasts with the export of other ER-translocating toxins, in which only the catalytic A subunit of the AB toxin enters the cytosol. However, like intoxication with these AB toxins, Pet intoxication was inhibited in a subset of mutant CHO cell lines with aberrant activity in the ER-associated degradation pathway of ER-to-cytosol translocation. This is the first report which documents the cell surface-to-ER and ER-to-cytosol trafficking of a bacterial non-AB toxin.

Human hololactoferrin: endocytosis and use as an iron source by the parasite Entamoeba histolytica.

Entamoeba histolytica is an enteric protozoan that exclusively infects human beings. This parasite requires iron for its metabolic functions. Lactoferrin is a mammalian glycoprotein that chelates extracellular iron on mucosal surfaces, including the surface of the large intestine, where E. histolytica initiates infection. This work examined the interaction in vitro of E. histolytica trophozoites with human hololactoferrin (iron-saturated lactoferrin). A minimum concentration of 50 microM Fe from hololactoferrin supported growth of the amoeba. Amoebic binding sites for hololactoferrin were different from those for human apolactoferrin, holotransferrin and haemoglobin. One amoebic hololactoferrrin-binding polypeptide of 90 kDa was found, which was not observed after treatment of trophozoites with trypsin. Hololactoferrin-binding-protein levels increased in amoebas starved of iron, or grown in hololactoferrin. Internalization of hololactoferrin was inhibited by filipin. Endocytosed hololactoferrin colocalized with an anti-chick embryo caveolin mAb in amoebic vesicles, and lactoferrin was further detected in acidic vesicles; amoebic caveolin of 22 kDa was detected by Western blotting using this antibody. Cysteine proteases from amoebic extracts were able to cleave hololactoferrin. Together, these data indicate that E. histolytica trophozoites bind to hololactoferrin through specific membrane lactoferrin-binding proteins. This ferric protein might be internalized via caveolae-like microdomains, then used as an iron source, and degraded.