The Skin Microbiome of Patients With Atopic Dermatitis Normalizes Gradually During Treatment.

Background: Atopic dermatitis (AD) is characterized by an altered skin microbiome dominantly colonized by S. aureus. Standard treatment includes emollients, anti-inflammatory medications and antiseptics. Objectives: To characterize changes in the skin microbiome during treatment for AD. Methods: The skin microbiomes of children with moderate-to-severe AD and healthy children were investigated in a longitudinal prospective study. Patients with AD were randomized to receive either standard treatment with emollients and topical corticosteroids or standard treatment with the addition of dilute bleach baths (DBB) and sampled at four visits over a three-month period. At each visit, severity of AD was measured, swabs were taken from four body sites and the composition of the microbiome at those sites was assessed using 16S rRNA amplification. Results: We included 14 healthy controls and 28 patients. We found high relative abundances of S. aureus in patients, which correlated with AD severity and reduced apparent alpha diversity. As disease severity improved with treatment, the abundance of S. aureus decreased, gradually becoming more similar to the microbiomes of healthy controls. After treatment, patients who received DBB had a significantly lower abundance of S. aureus than those who received only standard treatment. Conclusions: There are clear differences in the skin microbiome of healthy controls and AD patients that diminish with treatment. After three months, the addition of DBB to standard treatment had significantly decreased the S. aureus burden, supporting its use as a therapeutic option. Further study in double-blinded trials is needed.

Characterization of gallium resistance induced in a Pseudomonas aeruginosa cystic fibrosis isolate.

The repurposing of gallium nitrate as an antibacterial, a drug used previously for the treatment of hypercalcemia, is a plausible alternative to combat infections by Pseudomonas aeruginosa, since it has antipseudomonal properties in vitro and in vivo in animal models and in human lung infections. Furthermore, gallium nitrate tolerance in clinical isolates is very rare. Nevertheless, studies on the reference strains PA14 and PAO1 show that resistance against gallium nitrate is achieved by decreasing gallium intracellular levels by increasing the production of pyocyanin. In this work, we induced resistance in a cystic fibrosis P. aeruginosa isolate and explored its resistance mechanisms. This isolated strain, INP-58M, was not a pyocyanin producer, and its pyoverdine levels remained unchanged upon gallium addition. However, it showed higher activities of NADPH-producing enzymes and the antioxidant enzyme SOD when gallium was added, which suggests a better antioxidant response. Remarkably, gallium intracellular levels in the resistant isolate were higher than those of the parental strain at 20 h but lower after 24 h of culture, suggesting that this strain is capable of gallium efflux.

Helicobacter pylori infection and serum leptin, obestatin, and ghrelin levels in Mexican schoolchildren.

BackgroundThere is little information about the possible role of Helicobacter pylori infection on appetite-regulating peptides in children. This study evaluated the association between H. pylori infection and serum levels of ghrelin, leptin, and obestatin in schoolchildren.MethodsOne hundred seventy-eight schoolchildren, students at boarding schools in Mexico City, participated. H. pylori infection status was determined every 6 months for 1 year by a breath test using 13C-urea; schoolchildren with consistently positive or negative results were selected to participate. Age, sex, and body mass index (BMI) were recorded. Serum concentrations of total ghrelin, leptin, and obestatin via specific enzyme-linked immunosorbent assays were determined.ResultsSchoolchildren with H. pylori infection had lower concentration of leptin, -0.54 pg/ml (95% CI: -0.98 to -0.09), compared to the schoolchildren without infection, after adjustment by age, gender, and BMI. And the children with the infection had a median of obestatin lower in 0.99 ng/ml (95% CI: -1.93 to -0.06) compared with the uninfected children after adjustment by BMI.ConclusionAssociation was found between H. pylori infection and decreased serum concentrations of leptin and obestatin. These results suggest that in schoolchildren, H. pylori infection affects the levels of hormones implicated in regulating appetite and energy homeostasis.

High variability in quorum quenching and growth inhibition by furanone C-30 in Pseudomonas aeruginosa clinical isolates from cystic fibrosis patients.

Pseudomonas aeruginosa colonizes the lungs of cystic fibrosis patients causing severe damage. This bacterium is intrinsically resistant to antibiotics and shows resistance against new antimicrobials and its virulence is controlled by the quorum-sensing response. Thus, attenuating its virulence by quorum quenching instead of inhibiting its growth has been proposed to minimize resistance; however, resistance against the canonical quorum quencher furanone C-30 can be achieved by mutations leading to increased efflux. In the present work, the effect of C-30 in the attenuation of the QS-controlled virulence factors elastase and pyocyanin was investigated in 50 isolates from cystic fibrosis patients. The results demonstrate that there is a high variability in the expression of both elastase and pyocyanin and that there are many naturally resistant C-30 strains. We report that the main mechanism of C-30 resistance in these strains was not due to enhanced efflux but a lack of permeability. Moreover, C-30 strongly inhibited the growth of several of the isolates studied, thus imposing high selective pressure for the generation of resistance.

Plasticity Region Genes jhp0940, jhp0945, jhp0947, and jhp0949 of Helicobacter pylori in Isolates from Mexican Children.

BACKGROUND: The genes jhp0940, jhp0945, jhp0947, and jhp0949 belong to the plasticity region of the Helicobacter pylori genome. Due to their prevalence in isolates from patients with gastritis, duodenal ulcer, and gastric cancer, they have been proposed as markers of gastroduodenal diseases. These genes are associated with pro-inflammatory cytokine induction through the NF-κB activation pathway. Nevertheless, the status of these genes is unknown in H. pylori isolates from children. The aim of the present work was to determine the frequency of the jhp0940-jhp0945-jhp0947-jhp0949 genes in H. pylori isolates from children. MATERIALS AND METHODS: We identified the jhp0940, jhp0945, jhp0947, and jhp0949 genes and the relationship of each with the virulence factors cagA, cagPAI, and dupA by PCR in 49 isolates of H. pylori from children. The results were corroborated using dot blots. In addition, we compared the prevalence of these genes with the prevalence in adults. RESULTS: The prevalence of jhp0940 (53.1%), jhp0945 (44.9%), jhp0947 (77.6%), and jhp0949 (83.7%) was determined in the isolates from children, as was the prevalence of the virulence genes cagA (63.3%), cagPAI (71.4%), and dupA (37.5%). No association was found between the four genes of the plasticity region and the virulence genes. The presence of the intact locus integrated by jhp0940-jhp0945-jhp0947-jhp0949 was very common among the isolates from children. CONCLUSION: The genes jhp0940, jhp0947, and jhp0949 were present in more than 50% of the H. pylori isolates, and the joint presence of jhp0940-jhp0945-jhp0947-jhp0949 was very frequent. The frequency of these genes in isolates from children could contribute to the virulence of H. pylori and the evolution of the infection.

Gallium induces the production of virulence factors in Pseudomonas aeruginosa.

The novel antimicrobial gallium is a nonredox iron III analogue with bacteriostatic and bactericidal properties, effective for the treatment of Pseudomonas aeruginosa in vitro and in vivo in mouse and rabbit infection models. It interferes with iron metabolism, transport, and presumably its homeostasis. As gallium exerts its antimicrobial effects by competing with iron, we hypothesized that it ultimately will lead cells to an iron deficiency status. As iron deficiency promotes the expression of virulence factors in vitro and promotes the pathogenicity of P. aeruginosa in animal models, it is anticipated that treatment with gallium will also promote the production of virulence factors. To test this hypothesis, the reference strain PA14 and two clinical isolates from patients with cystic fibrosis were exposed to gallium, and their production of pyocyanin, rhamnolipids, elastase, alkaline protease, alginate, pyoverdine, and biofilm was determined. Gallium treatment induced the production of all the virulence factors tested in the three strains except for pyoverdine. In addition, as the Ga-induced virulence factors are quorum sensing controlled, co-administration of Ga and the quorum quencher brominated furanone C-30 was assayed, and it was found that C-30 alleviated growth inhibition from gallium. Hence, adding both C-30 and gallium may be more effective in the treatment of P. aeruginosa infections.

Detección de la Beta lactamasa de espectro OXA-141 en cepas de Pseudomonas aeruginosa aisladas de pacientes con fibrosis quística / No disponible

Introducción: Los objetivos de este trabajo fueron estudiar la presencia de -lactamasas de espectro extendido (BLEE), investigar la ubicación de los genes que codifican para esas enzimas y determinar la relación clonal de cepas de Pseudomonas aeruginosa resistentes a la ceftazidima aisladas de pacientes mexicanos con fibrosis quística. Metodología: Se determinó el perfil de resistencia a 11 antibióticos (CLSI) y la detección fenotípica de las BLEE siguiendo un método de difusión en discos de papel filtro adaptado para P. aeruginosa. La caracterización de los genes de las BLEE y de integrones se realizó por PCR y secuenciación del ADN, mientras que el análisis de la relación clonal se realizó por PFGE. Resultados: De las 148 cepas en estudio, 22 resultaron resistentes a la ceftazidima y el análisis por PCR y secuenciación reveló la presencia del genblaOXA-141 en 7 cepas, 6 resistentes y una sensible a la ceftazidima. Asimismo, blaGES se detectó en 11 cepas. Los genes intI2 e intI3 no se detectaron por PCR, pero en las 6cepas resistentes a la ceftazidima se descubrió el gen blaOXA-141 en un integrón de la clase 1. El análisis de la relación clonal de los aislamientos mostró que la mayoría de los pacientes se infectaron a lo largo del periodo de estudio con cepas de P. aeruginosa que presentaron patrones diferentes, principalmente en los individuos que no tenían relación familiar. Conclusiones: Este trabajo demuestra la existencia del gen blaOXA-141 asociado a un integrón de clase 1 en varias cepas de P. aeruginosa, así como de genes blaGES cuya localización y variante están en estudio en el grupo de investigación. Lo anterior, aunado a la diversidad de cepas capaces de infectar a individuos sensibles, sugiere un riesgo de dispersión de las cepas de P. aeruginosa productoras de BLEE entre la población mexicana que padece fibrosis quística (AU)

Introduction: The aims of this research were to study the presence of extended spectrum -lactamases(ESBL) to investigate the location of the genes encoding these enzymes, and determine the clonal relationship of strains of ceftazidime-resistant Pseudomonas aeruginosa isolated from Mexican patients with cystic fibrosis. Methods: We determined the resistance profile to 11 antibiotics (CLSI) and phenotypic ESBL detection following a disk diffusion method adapted for P. aeruginosa. Characterization of ESBL genes and integrons was performed by polymerase chain reaction (PCR) and DNA sequencing, while analysis of the clonal relationship was performed by pulsed field gel electrophoresis (PFGE) Results: Of the 148 strains studied, 22 were resistant to ceftazidime, and analysis by PCR and sequencing revealed the presence of the gene blaOXA-141 in 7 strains, 6 of which were resistant and one, susceptible to ceftazidime. In addition, blaGES was detected in 11 strains. intI2 and intI3 genes were not detected byPCR, but in the 6 ceftazidime-resistant strains, the blaOXA-141 gene was determined in a class 1 integron. Analysis of the clonal relationship of isolates showed that the majority of patients were infected during the study period with P. aeruginosa strains that exhibit different patterns, especially in individuals without a familial relationship. Conclusions: This report demonstrates the existence of the blaOXA-141 gene associated with a class 1 integron in several strains of P. aeruginosa, as well as blaGES genes, and their location and variants are being studied by our research group. This, combined with the diversity of strains able to infect several susceptible individuals, suggests the risk of spread of P. aeruginosa-strain ESBL producers among Mexican populations with cystic fibrosis (AU)

[Experimental bacterial contamination of bile and liver in mongrel dogs: an alternative treatment with cephalone, a hybrid of cephalosporine fluoroquinolone]. / Contaminación bacteriana experimental de bilis e hígado en perros criollos. Tratamiento alternativo con (cefalona), un híbrido de cefalosporina y fluoroquinolona.

OBJECTIVES: A longitudinal, randomized, single blind study was done to evaluate the efficacy of an antibacterial hybrid molecule (beta-lactamic-fluoroquinolone) named cephalone after biliary-enteric-bypass (BEB). MATERIAL AND METHODS: Four groups of mongrel dogs were operated on three consecutive periods. Cultures of bile and liver were obtained and assessed, followed by obliteration of common bile duct and BEB to groups A, B and C. Group D served as a control. Ten days later the group A received conventional treatment based on ampicillin/gentamicin and groups B and C, cephalone in two different concentration schemes during 10 consecutive days. Further samples were processed for bacteria and additional liver biopsies were obtained for histopathological analysis. RESULTS: All three treatments reverted bacterial contamination in the liver and most of the bile samples were negative or showed a significant decrease in the number of colony forming units (p = 0.002). Histopathological analysis proved no lesions. CONCLUSIONS: Comparison of efficacy among antibacterial treatments revealed undistinguishable efficacy in this short-term assessment of bacterial contamination after BEB in dogs. The use of cephalone could be considered as a viable treatment or prophylaxis in bacterial infections occurring after BEB. Further studies are needed to assess long-term impact of the cephalone in this setting.

[Detection of extended spectrum ß-lactamase OXA-141 in Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis]. / Detección de la ß-lactamasa de espectro extendido OXA-141 en cepas de Pseudomonas aeruginosa aisladas de pacientes con fibrosis quística.

INTRODUCTION: The aims of this research were to study the presence of extended spectrum ß-lactamases (ESBL) to investigate the location of the genes encoding these enzymes, and determine the clonal relationship of strains of ceftazidime-resistant Pseudomonas aeruginosa isolated from Mexican patients with cystic fibrosis. METHODS: We determined the resistance profile to 11 antibiotics (CLSI) and phenotypic ESBL detection following a disk diffusion method adapted for P. aeruginosa. Characterization of ESBL genes and integrons was performed by polymerase chain reaction (PCR) and DNA sequencing, while analysis of the clonal relationship was performed by pulsed field gel electrophoresis (PFGE). RESULTS: Of the 148 strains studied, 22 were resistant to ceftazidime, and analysis by PCR and sequencing revealed the presence of the gene bla(OXA-141) in 7 strains, 6 of which were resistant and one, susceptible to ceftazidime. In addition, bla(GES) was detected in 11 strains. intI2 and intI3 genes were not detected by PCR, but in the 6 ceftazidime-resistant strains, the bla(OXA-141) gene was determined in a class 1 integron. Analysis of the clonal relationship of isolates showed that the majority of patients were infected during the study period with P. aeruginosa strains that exhibit different patterns, especially in individuals without a familial relationship. CONCLUSIONS: This report demonstrates the existence of the bla(OXA-141) gene associated with a class 1 integron in several strains of P. aeruginosa, as well as bla(GES) genes, and their location and variants are being studied by our research group. This, combined with the diversity of strains able to infect several susceptible individuals, suggests the risk of spread of P. aeruginosa-strain ESBL producers among Mexican populations with cystic fibrosis.

Identification of Helicobacter pylori strain cagPAI+ and cagPAI- Antigens by IgG antibodies from sera of experimentally colonized meriones unguiculatus (Mongolian gerbils).

BACKGROUND: Mongolian gerbils that are experimentally infected with Helicobacter pylori develop a chronic inflammation that is similar to natural infections in humans. The aim of this study was to compare the antigens of H. pylori cagPAI+ and cagPAI- strains that are expressed during Meriones unguiculatus colonization. MATERIALS AND METHODS: We identified H. pylori cagPAI+ and cagPAI- strain antigens via Western blotting of samples from Mongolian gerbils that were subjected to unique, mixed, and sequential bacterial infections. RESULTS: The antigens from the J99/CG3 (cagPAI+) strain had a lower molecular weight than the antigens from the 251F/CG3 (cagPAI-) strain. There were fewer identified antigens in the single unique infections compared with the mixed and sequential infections. The number of recognized antigens that had a frequency of recognition >60% was higher for the simultaneous and sequential infection groups compared with the single infection group. A 57-kDa antigen was present in >60% of the samples and four of the five experimental groups. Antigens specific to each bacterial strain were identified; the 190- and 158-kDa antigens appear to be specific for cagPAI-, and the 70-kDa antigen appears to be specific for cagPAI+. CONCLUSIONS: In this study, we identified antigens that are common and specific to the H. pylori cagPAI+ and cagPAI- strains.

Study of simultaneous experimental colonization of Meriones unguiculatus (Mongolian gerbils) by cagPAI+ and cagPAI- strains of Helicobacter pylori.

Helicobacter pylori has a chromosomal pathogenicity island (cagPAI), and the presence or absence of this Island places the microorganism into two types of strains: cagPAI+ which is associated to serious infectious processes, and cagPAI- related to mild to moderate infectious events. Simultaneous colonization by cagPAI+ and cagPAI- strains is frequent and these bacteria can interact among themselves. The aim of this project was to analyze the interaction between cagPAI+ and cagPAI- strains of H. pylori in experimental infection, using the Mongolian gerbil as an experimental animal model. We employed J99 (cagPAI+) and 251F (cagPAI-) strains, and obtained 3 derivate strains in successive isolation from experimentally infected gerbils. By RAPD-PCR we found that cagPAI+ and cagPAI- underwent genetic rearrangement during the gerbil-adaptation process. We identified individual isolates from gerbils, and by in situ hybridization we established that both type of strains were able to colonize the same regions of the host's stomach, and induce a mild to moderate inflammatory process. We studied the competence between cagPAI+ and cagPAI- strains by simultaneous and sequential infections. The study shows that in both colonization experiments, the cagPAI- strains were more efficient than cagPAI+ strains in colonizing the infected host by displacing cagPAI+.

Extemporaneous suspension of propafenone: attending lack of pediatric formulations in Mexico.

BACKGROUND: Physicians have frequently encountered difficulties when prescribing drugs not available in doses suitable for pediatric age groups. Furthermore, children have difficulty swallowing tablets. This study aimed to determine the stability of an oral propafenone suspension made from commercial tablets with a syrup vehicle and to establish its reliable use with children. METHODS: An extemporaneous suspension of propafenone 1.5 mg/ml was prepared with commercial tablets. Its physicochemical and microbiologic stability was established by constant monitoring during 90 days at room temperature (15 +/- 5 degrees C) and at refrigeration (3-5 degrees C). Plasma levels of propafenona were measured in two children with supraventricular tachycardia at steady state. RESULTS: The suspension was stable, maintaining its original physicochemical and microbiologic properties. Moreover, no apparent changes in color or odor were observed. Plasma levels of propafenone in patients demonstrated therapeutic concentrations after they had taken the suspension, with no unwanted outcome. CONCLUSIONS: The conservation of both physicochemical and microbiologic stability of the suspension represents an option for the administration of propafenone to children.

Resistance of uropathogenic bacteria to first-line antibiotics in mexico city: A multicenter susceptibility analysis.

UNLABELLED: Abstract. BACKGROUND: Growing antibiotic resistance demands the constant reassessment of antimicrobial efficacy, particularly in countries with wide antibiotic abuse, where higher resistance prevalence is often found. Knowledge of resistance trends is particularly important when prescribing antibiotics empirically, as is usually the case for urinary tract infections (UTIs). Currently, in Mexico City, ampicillin, cotrimoxazole (trimethoprim/sulfamethoxazole), and ciprofloxacin are used as "first-line" antibiotic treatment for UTI. OBJECTIVE: The aim of this study was to analyze the resistance of bacterial isolates to antibiotics, with a focus on first-line antibiotics, in Mexican pediatric patients and sexually active or pregnant female outpatients. METHODS: In this multicenter susceptibility analysis, bacterial isolates from urine samples collected from pediatric patients and sexually-active or pregnant female outpatients presenting with acute, uncomplicated UTIs in Mexico City from January 2006 through June 2006, were included in the study. Samples were tested for susceptibility to 10 antibiotics by the disk-diffusion method. RESULTS: Four-hundred and seventeen bacterial isolates were derived from sexually active or pregnant female outpatients (324 Escherichia coli) and pediatric patients (93 Klebsiella pneumoniae). We found a high prevalence of resistance towards the drugs used as "first-line" when treating UTIs: ampicillin, cotrimoxazole, and ciprofloxacin (79%, 60%, and 24% resistance, respectively). Ninety-eight percent of K pneumoniae isolates were resistant to ampicillin, whereas 66% of the E coli isolates were resistant to cotrimoxazole. Resistance towards third-generation cephalosporins was also high (6%-8% of E coli and 10%-28% of K pneumoniae). This was possibly caused by chromosomal ß-lactamases, as 30% of all isolates were also resistant to amoxicillin/clavulanate. In contrast, 98% of the E coli isolates and 84% of the K pneumoniae strains (96% of all isolates) were found to be susceptible to nitrofurantoin, which has been in clinical use for much longer than most other drugs in this study. CONCLUSION: In these urine samples from laboratories in Mexico City, resistance of K pneumoniae and E coli isolates to first-line treatment (ampicillin, cotrimoxazole, or ciprofloxacin) of UTI was high, whereas most E coli and K pneumoniae isolates were susceptible to nitrofurantoin and the fourth-generation cephalosporin cefepime. (Curr Ther Res Clin Exp. 2007;68:120-126) Copyright © 2007 Excerpta Medica, Inc.

[RAPD-PCR characterization of Pseudomonas aeruginosa strains obtained from cystic fibrosis patients]. / Caracterización, por RAPD-PCR, de aislados de Pseudomonas aeruginosa obtenidos de pacientes con fibrosis quística.

OBJECTIVE: To characterize P. aeruginosa strains isolated from bronchoalveolar lavage fluid of cystic fibrosis (CF) patients over a 3 year period. MATERIAL AND METHODS: A prospective follow-up study was carried out in a population of cystic fibrosis patients. The random amplified polymorphic DNA (RAP.D) technique was used to amplify DNA of P. aeruginosa strains isolated from bronchoalveolar lavage fluid samples of five CF patients from the Servicio de Neumología y Cirugía del Tórax del Instituto Nacional de Pediatría (Mexico City Chest Clinic of the National Pediatrics Institute) in Mexico City, between June 1996 and June 2002. Amplification patterns were established for each isolate to accurately identify all strains and to carry out an epidemiological analysis of P. aeruginosa among the selected CF patients. RESULTS: Eighteen different DNA amplification patterns were defined and used to identify each P. aeruginosa strain isolated from the different bronchoalveolar lavage samples. No correlation was observed between the different P. aeruginosa strain genotypes and mucoid or non-mucoid phenotypes, as strains with different phenotypes showed similar amplification patterns. Several strains with different amplification patterns were identified in samples obtained from the same patient, suggesting coinfection with ore than one P. aeruginosa strain. Two siblings with CF shared similargenotypes, suggesting the occurrence of cross- contamination. Similar genotypes of P. aeruginosa strains were isolated throughout the study period. CONCLUSION: Genotypic characterization of P. aeruginosa strains in CF patients allows more accurate epidemiological analyses of this important host-agent relationship.

Caracterización, por RAPD-PCR, de aislados de Pseudomonas aeruginosa obtenidos de pacientes con fibrosis quística / RAPD-PCR characterization of Pseudomonas aeruginosa strains obtained from cystic fibrosis patients

OBJETIVO: Caracterizar a las cepas de P aeruginosa aisladas de lavados broncoalveolares de pacientes con fibrosis quística a lo largo de un periodo de tres años. MATERIAL Y MÉTODOS: Estudio prospectivo, de seguimiento de una población de pacientes con fibrosis quística. Se utilizó la técnica de la amplificación del ADN empleando PCR con bajas condiciones de especificidad (Random amplified polymorphic DNA, RAPD-PCR) para la amplificación del ADN de cepas de P aeruginosa aisladas de lavados broncoalveolares de cinco pacientes con fibrosis quística, provenientes del Servicio de Neumología y Cirugía del Tórax del Instituto Nacional de Pediatría de la Ciudad de México, en el periodo de junio de 1996 a junio de 2002; se establecieron los patrones de amplificación de cada aislamiento, lo que permitió la identificación precisa de todas las cepas aisladas y el estudio de la epidemiología de P aeruginosa en los pacientes seleccionados con dicha enfermedad. RESULTADOS: Se definieron 18 patrones de amplificación del ADN que permitieron identificar a cada cepa de P aeruginosa aislada en las diferentes muestras de lavado broncoalveolar; no se encontró relación entre el fenotipo de P aeruginosa (mucoide o no mucoide) y el genotipo de cada aislamiento, ya que cepas con fenotipos distintos mostraron patrones de amplificación semejantes; en nuestros pacientes se identificaron cepas con patrones de amplificación distintos a partir de una misma muestra, lo que sugiere la presencia de infecciones simultáneas por más de una cepa de P aeruginosa; se demostró que dos hermanos con la enfermedad compartían cepas con genotipos semejantes, lo que sugiere una contaminación cruzada entre ambos, y se demostró el aislamiento de cepas de P aeruginosa con genotipos semejantes a lo largo de los periodos estudiados. CONCLUSIONES: La identificación mediante la caracterización genotípica de las cepas de P aeruginosa aisladas de los pacientes con fibrosis quística permite llevar a cabo estudios más precisos de la epidemiología de esta importante relación huésped-parásito.

Identification of Serratia marcescens populations of nosocomial origin by RAPD-PCR.

BACKGROUND: Serratia marcescens has been increasingly identified as a cause of infection in the immunocompromised host and in high-mortality-rate nosocomial outbreaks. It is thus important to use identification methods that allow study of the dynamics and evolution of nosocomial S. marcescens strains. The aim of this study was to identify S. marcescens strains isolated from nosocomial outbreaks in two pediatric hospitals by random amplification polymorphic DNA polymerase chain reaction (RAPD-PCR). METHODS: RAPD-PCR was used to study five S. marcescens populations isolated from four different nosocomial outbreaks that occurred in two pediatric hospitals. This method was compared with the widely used biotyping system described by Grimont and Grimont. RESULTS: The combination of biotypification and RAPD-PCR allowed accurate identification of S. marcescens strains isolated in nosocomial outbreaks at pediatric hospitals; by RAPD-PCR, we were able to analyze clonal variations in S. marcescens populations. We established bacterial dissemination patterns in hospital environments according to hospital administration of medical services and compared changes in bacterial DNA amplification patterns in each hospital related with clonal variations by selective pressures. CONCLUSIONS: RAPD-PCR is a useful method to identify S. marcescens strains associated with nosocomial outbreaks.

Comparación de los resultados del examen químico, citológico y cultivo de la orina recolectada en pañales desechables, bolsa colectora de plástico y chorro medio / Chemical, cytological and culture examination of ureine obtained by disposable diapers, autoadherible steril bags and midstream void technique

En edades pediátricas, la recolección de orina para examen químico-citológico se lleva a cabo por diferentes métodos, cada uno con sus inconvenientes. El más simple y que se usa mucho, pero sin saber su confiabilidad, es el exprimir la orina de un pañal. Se recolectó orina mediante la utilización de tres diferentes métodos en cada paciente: bolsas de plástico autoadheribles; chorro medio de la micción (estándar de oro) y mediante su extracción de pañales desechables, succionando la orina de la parte medial del mismo, con el fin de realizar examen general de orina y urocultivo en 40 varones sanos o enfermos, pero no de vías urinarias. El análisis estadístico no reportó diferencias en cuanto a pH, densidad urinaria, proteínas, leucocitos, bacterias, hemoglobina, glucosa y bilirrubinas. En cuanto a los urocultivos, tampoco se encontraron diferencias estadísticas significativas. El pañal no detectó un paciente con infección de vías urinarias por Candida albicans. Utilizar un pañal desechable es un método recomendado como "de rutina" en pediatría; se requieren más estudios en pacientes con patología de vías urinarias