[Impact of eradication of Pseudomonas aeruginosa on survival in Mexican patients with cystic fibrosis]. / Impacto de la erradicación de Pseudomonas aeruginosa sobre la sobrevida en pacientes con fibrosis quística del noreste de México.

INTRODUCTION: Patients with cystic fibrosis (CF) present lower airway infection with Pseudomonas aeruginosa. Treatment of initial infection is fundamental to reduce subsequent damage. MATERIAL AND METHODS: We evaluated the efficacy of eradication treatment of P. aeruginosa in patients with CF from northeast Mexico using two protocols: inhaled colistin/oral ciprofloxacin and nebulized tobramycin 300 mg/oral ciprofloxacin. The intervention group included 17 patients with CF and recent infection with P. aeruginosa. The control group consisted of 23 chronically colonized patients of comparable age. RESULTS: Patients received 27 courses of eradication treatment. P. aeruginosa was eradicated in 21/27 (77.77%). The infection free period was 16.9, 11.7 months (colistin) and 17 ± 9.7 months (tobramycin) with no statistically significant difference (P = 0.97). CONCLUSIONS: Treated patients maintained normal lung function, better nutritional status, and a better chest X-ray score. In the control group 17/23 (73.9%) patients died with no deaths in the study group.

Ultrastructural findings in semen samples of infertile men infected with Chlamydia trachomatis and mycoplasmas.

The aim of this study was to describe the ultrastructural features observed in semen samples of men with infertility and subfertility of unknown cause infected with Chlamydia trachomatis and mycoplasmas. The findings observed by ultrastructure included destruction or persistence of bacteria in leukocytes, phagocytosis of spermatozoa by leukocytes, and structural damage of spermatozoa.

In vitro antibacterial activity of bovine dialyzable leukocyte extract.

The rapidly developing resistance of many infectious pathogenic organisms to modern drugs has spurred scientists to search for new sources of antibacterial compounds. One potential candidate, bDLE (dialysis at 10 to 12 kDa cut-off) and its fractions ("S" and "L" by 3.5 kDa cut-off and I, II, III, and IV by molecular exclusion chromatography), was evaluated for antibacterial activity against pathogenic bacterial strains (Staphylococcus aureus, Streptococcus pyogenes, Lysteria monocytogenes, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi) using standard antimicrobial assays. A minimum inhibitory concentration (MIC) of bDLE and its fractions was determined by agar and broth dilutions methods. Only bDLE and its "S" fraction had an effect upon all bacteria evaluated (MIC ranging from 0.29 to 0.62 U/ml), and the bactericidal and bacteriostatic effects (evaluated by MTT assay) were bacterial species-dependent. These results showed a remarkable in vitro antibacterial property of bDLE against several pathogenic bacteria.

Diagnostic utility of invasive tests and serology for the diagnosis of Helicobacter pylori infection in different clinical presentations.

BACKGROUND: Invasive and noninvasive tests are used for the diagnosis of Helicobacter pylori infection. The aim of this study was to determine the diagnostic utility of rapid urease test (RUT), culture, histology and serology for the diagnosis of H. pylori in patients with different clinical presentations. METHODS: We studied 527 consecutive patients (mean age, 52.5 years; F:M, 1.3; age range 15-89 years) enrolled at the Hospital Universitario, Universidad Autónoma de Nuevo León. Patients had gastric cancer (GC, 9.1%), non-ulcer dyspepsia (NUD, 81.4%), or peptic ulcer disease (PUD, 9.1%). The infection by H. pylori was determined by histology, rapid urease test, culture, and serology. Patients were determined as infected with H. pylori if at least a) two invasive tests were positive and b) two tests were positive (invasive or non-invasive). Diagnostic utility was calculated for each assay. RESULTS: Prevalence of infection in the whole studied population was 50.9%. In NUD patients the prevalence was 51.3%, in PUD patients 58.3%, and in GC patients 39.6%. When we used the first diagnostic criteria, for the whole studied population, the RUT was the most reliable test, followed by the culture. Histology had the best sensitivity for the whole studied population and NUD patients and RUT had the best sensitivity value for the GC patients. In the whole studied population, NUD and GC patients, RUT and culture had the best specificity, accuracy and PPV. For PUD patients, serology had the best performance. When we used the second diagnostic criteria, histology and serology had a better performance compared with the results obtained with the first diagnostic criteria. CONCLUSIONS: Diagnostic utility of the tests varies according to the clinical presentations, which should be considered in the selection of the diagnostic test for the detection of H. pylori.

Role of p53 codon 72 polymorphism in the risk of development of distal gastric cancer.

OBJECTIVE: Mutations in the codon 72 of exon 4 in the p53 gene have been associated with higher risk in the development of several types of cancer. This polymorphism occurs with two alleles encoding either arginine (CGC) or proline (CCC). The aim of this study was to assess the role of the codon 72 polymorphism of p53 in the risk for the development of distal gastric cancer (GC) in a Mexican population. MATERIAL AND METHODS: We studied 247 patients who were enrolled at the Servicio de Gastroenterologia, Hospital Universitario "Dr. José Eleuterio González" Universidad Autónoma de Nuevo León. The study group included 65 distal GC cases [mean age, 58.2 (22-84), median = 60, F:M = 0.6] and 182 patients without evidence of GC [mean age 53.9 (18-89), median = 53, F:M = 1.07) as the control group. The polymorphism in the codon 72 of the p53 gene was determined by PCR-RFLP in all the patients. RESULTS: As expected, the majority of GC patients were old male. We found a previously unknown association of the Arg/Arg genotype and distal GC (OR: 1.96, 95% confidence interval [CI] = 1.06-3.61, p =0.03). Because of age and gender differences, cases and controls were matched in those two variables and the association of Arg/Arg genotype with distal GC persisted (OR: 2.29, 95% CI = 1.22-4.32, p = 0.01). When cases and controls were matched by age, gender, H. pylori positivity and excluding patients with atrophic gastritis and/or intestinal metaplasia (n=97) the association was stronger (OR = 2.37, 95% CI = 1.18-4.77, p = 0.01). CONCLUSIONS: The results of this study suggest that the carriage of the Arg/Arg genotype could be associated with the development of distal GC in this Mexican population.

Role of the polymorphic IL-1B, IL-1RN and TNF-A genes in distal gastric cancer in Mexico.

Several cytokine gene polymorphisms have been associated with increased risk of distal gastric cancer (GC) and its precursor histological markers in Caucasian, Asian and Portuguese populations although little is known about their role in other ethnic groups. Our study investigates the role of the IL-1B-31, IL-1RN and TNF-A-308 gene polymorphisms as risk factors for the development of GC in a Mexican population. We studied 278 patients who were enrolled at the Hospital Universitario Dr. Jose Eleuterio Gonzalez, Universidad Autonoma de Nuevo Leon. The subjects were divided into 2 groups. Sixty-three patients with histologically confirmed distal GC (mean age = 58.8 years, range = 22-84, F:M = 0.56), and 215 patients with no evidence of distal or proximal GC (mean age = 56.1 years, range = 18-92, F:M = 1.17). The IL-1B-31 and the TNF-A-308 polymorphisms were determined by PCR-RFLP and pyrosequencing, respectively, in all cases and controls. The VNTR polymorphism in intron 2 of the 1L-1RN gene was typed by PCR in 25 cases and 201 controls. The H. pylori status was determined by histology, rapid urease test, culture and serology for non-cancer controls and by histology for the GC cases. The carriage of the proinflammatory IL-1B-31*C allele was associated with increased risk of distal GC (odds ratio [OR] = 7.63, 95% confidence interval [CI] = 1.73-46.94, p = 0.003). When cases and controls were matched by age and gender, the OR value was higher (OR = 8.05, 95% CI = 1.8-50.22, p = 0.001). When only H. pylori GC cases and controls were compared, the OR value was 7.8 (95% CI = 1.05-161.8, p = 0.04). No association was found between any of the other polymorphisms studied and distal GC. In this Mexican population, the IL-1B proinflammatory genotype increases the risk of distal GC. These findings are similar to previous reports in Caucasian populations and underscore the importance of cytokine gene polymorphisms in the development of distal GC.

Association of gastric cancer, HLA-DQA1, and infection with Helicobacter pylori CagA+ and VacA+ in a Mexican population.

BACKGROUND: The goal of this study was to determine the importance of Helicobacter pylori CagA+, VacA+, and HLA-DQA1 alleles in a Mexican population with gastric cancer (GC). METHODS: We studied a group of Mexican patients (cases) with distal GC (n=22) or high-grade dysplasia (HGD; n=8) (mean age, 62.7 years, F : M=0.3; age range, 33-84 years) and 77 ethnically matched non-GC controls (mean age, 47.1 years; F : M=1.96; age range, 17-92 years). Both cases and controls were H. pylori-positive by at least two of the following diagnostic tests: rapid urease test, histology, culture, or serology. The presence of antibodies to CagA and VacA proteins was determined by Western blot, and the HLA-DQA1 typing was carried out by a polymerase chain reaction (PCR) sequence-specific primer method. RESULTS: The carriage of H. pylori CagA+, VacA+ strains was associated with GC or HGD (odds ratio [OR], 6.07; 95% confidence interval [CI], 1.56-27.57; P=0.005). The allele frequency of DQA1*0503 was significantly lower in the GC-HGD group than in the non-GC group (OR, 0.13; 95% CI, 0.02-0.59). Logistic regression analysis identified the carriage of HLA-DQA1*0503 as an independent protective factor for GC (OR, 0.19; 95% CI, 0.04-0.94) and colonization with H. pylori CagA+, VacA+ strains as an independent risk factor for GC (OR, 6.15; 95% CI, 1.69-22.37). CONCLUSIONS: Infection with H. pylori CagA+, VacA+ strains represents a significant risk for the development of GC. The absence of HLA-DQA1*0503 could be a host risk factor for the development of GC in Mexican patients.

Frequency of mutations in rpoB and codons 315 and 463 of katG in rifampin- and/or isoniazid-resistant Mycobacterium tuberculosis isolates from northeast Mexico.

A total of 48 isoniazid (INH)- and rifampin (RIF)-resistant Mycobacterium tuberculosis isolates, 19 INH-resistant isolates, and 9 RIF-resistant isolates were randomly selected and tested for detecting mutations at codons 315 and 463 of katG by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and/or for detecting mutations at a 69-bp region of the rpoB gene by the INNO-LiPA Rif TB assay. Of the 67 INH-resistant isolates tested, 36 (53.7%) showed the mutation at codon 315 of katG; however, none of them showed the mutation at codon 463. The majority of the RIF-resistant samples analyzed (49 of 57, 86.0%) reacted positive with one of the four R-type probes. The R5-pattern (S531L mutation) was the most frequently observed (31 of 57, 54.4%), followed by R4a-pattern (H526Y mutation) 13 isolates (22.8%), R4b-pattern (H526D mutation) 4 isolates (7.0%), and R2-pattern (D516V mutation) 1 isolate (1.8%). Overall, there was agreement between the line probe kit and phenotypic RIF-susceptibility test for 56 (98.2%) of 57 RIF-resistant isolates tested. These results show that the mutation analysis at codon 315 of katG could be used as a screening assay prior to standard susceptibility testing, whereas mutations in the rpoB gene could be used successfully as genetic markers to rapidly detect RIF-resistant M. tuberculosis clinical isolates from northeast Mexico.

Comparision of endoscopy-based and serum-based methods for the diagnosis of Helicobacter pylori.

UNLABELLED: Available commercial tests for the diagnosis of Helicobacter pylori infection are based on different types of antigen preparations and hence the diagnostic utility differs substantially. OBJECTIVE: To assess the diagnostic value of the determination of Immunoglobulin (Ig) A and IgG antibodies to H pylori whole cell (WC) and IgG antibodies to cytotoxin associated gene A (CagA) using an in-house ELISA in relation to the results obtained with different invasive methods. METHODS: The study population consisted of 251 Mexican adults, mean age 53 years, age range 15 to 92 years and female to male ratio of 1.5. Peptic ulcer disease was present in 10.8% of these patients, 5.2% had gastric cancer, 11.2% had esophagitis and 72.9% had nonulcer dyspepsia. Biopsy specimens from the body and the antrum of the stomach were obtained for culture, histology and rapid urease test. ELISAs to detect IgA and IgG WC and CagA antibodies were performed using serum. RESULTS: H pylori status was established by the results of the invasive tests. Eighty (31.9%) patients positive to the three tests and 38 (15.1%) negative to all the tests were identified. Based on this result, the sensitivity and specificity of the serology assays were 97.5% and 78.9% for the IgG WC and 70% and 73.7% for the IgA WC, respectively. However, if H pylori status was defined by the positive result of at least one or two invasive diagnostic tests, the sensitivity for the IgG WC decreased to 87.3% and 66.7% respectively, but the specificity was essentially the same. Similar results were obtained for the sensitivity and specificity of IgA using the same criteria. A low CagA prevalence was observed (39%). CONCLUSIONS: Testing for serological IgG antibodies to H pylori WC was the best to assess whether infection by H pylori was present. Neither the IgA WC nor the IgG CagA ELISAs add significant value in the diagnosis of H pylori.

Comparison of Helicobacter pylori prevalence in symptomatic patients in northeastern Mexico with the rest of the country: its association with gastrointestinal disease.

BACKGROUND: Prevalence of Helicobacter pylori varies among different geographic regions. The aim of this study was to assess H. pylori prevalence in symptomatic patients in northeastern Mexico and its possible association of H. pylori with disease. METHODS: We studied 261 symptomatic patients (female/male 1.44, mean age 53 years) who underwent gastrointestinal endoscopy at Hospital Universitario Dr. José Eleuterio González in Monterrey, Nuevo León, Mexico. Among patients included in this study, 209 (80.1%) had nonulcer dyspepsia (NUD), 30 (11.5%) peptic ulcer disease (PUD), and 22 (8.4%) high-grade dysplasia or gastric cancer. H. pylori status was determined by histology, positive rapid urease test, culture, or IgG whole-cell anti-H. pylori. Specific IgG antibodies for CagA status were determined by ELISA as previously described. Patients were defined as infected with H. pylori by positive results of two or more diagnostic tests used. RESULTS: Overall prevalence of H. pylori was 67.8%. According to clinical presentation, gender (male) was related with gastric cancer (p <0.01) and with PUD (p <0.05). Of 177 patients infected with H. pylori, 90 (50.8%) were seropositive for CagA antigen; in addition, H. pylori CagA+ was more common in patients with PUD (77.8%) than with NUD (43.2%) (p <0.05). However, no association was found between gastric cancer patients and presence of CagA+ H. pylori strains. CONCLUSIONS: H. pylori prevalence in symptomatic patients in northeastern Mexico is as high as the prevalence reported for the entire country. We confirmed that patients with gastric cancer and PUD are more likely to be male. CagA+ strains were associated with patients who presented PUD but not gastric cancer.

[Role of polymorphism of certain cytokines in gastric cancer in Mexico. Preliminary results]. / Papel de los polimorfismos de algunas citocinas en el cáncer gástrico en México. Resultados preliminares.

BACKGROUND: Interleukin-10, tumor necrosis factor alpha, Interleukin-1 beta and interleukin-1 receptor antagonist cytokines modulate the inflammatory response in presence of Helicobacter pylori. Pro-inflammatory interleukin 10 (IL-10-592, -1082), TNF alpha (TNF alpha-308), interleukin-1 beta and interleukin-1 receptor antagonist (IL-1B-31*C and IL-1RN*2/*2) genotypes have been associated with higher risk of gastric cancer in Caucasians. The aim of this study was to investigate whether these same genotypes are involved in susceptibility to gastric cancer in Mexican population. MATERIALS AND METHODS: DNA from 33 unrelated Mexican patients with histologically confirmed gastric cancer (n = 25) or high-grade dysplasia (n = 8) (mean age 62.7, F/M = 0.37) and 25 ethnically matched healthy controls (mean age = 39.9, F/M = 3.12) were studied. All cases and controls had evidence of H. pylori infection as shown by at least two positive results from the following diagnostic tests: rapid urease test; culture; histology, or detection of IgG anti-H. pylori antibodies. The -592, -1082 polymorphism in IL-10 gene, the -308 in TNF alpha gene, and the-31 polymorphism in the IL-1B gene were typed by 5' nuclease PCR assays (TaqMan) and the variable number of tandem repeats polymorphism in intron 2 of the 1L-1RN gene was typed by PCR and amplicon sizing as previously described (Nature 2000; 404: 398). RESULTS: Carriage of the pro-inflammatory IL-1B-31*C allele was associated with increased risk of gastric cancer or high-grade dysplasia (OR: 8.7, 95% confidence interval [CI] = 1.5-66.9). No association was found between any IL-IRN, IL-10 or TNF alpha genotypes and gastric cancer or high-grade dysplasia. Logistic regression analysis identified male gender and carriage of IL-1B-31*C as independent risk factors for gastric cancer (OR = 9.2, 95% CI = 2.4-34.5, and OR = 10, 95% CI = 1.6-64, respectively). CONCLUSIONS: The results of this preliminary study confirm that the pro-inflammatory IL-1B genotypes, as well as male gender, are risk factors for development of gastric cancer in Mexican population.

[Helicobacter pylori genotypes and their association with host's immune response]. / Genotipos de Helicobacter pylori y su asociación con la respuesta inmune del hospedero.

BACKGROUND DATA: The study of Helicobacter pylori phenotypes and genotypes is mainly focused on two groups of putative bacterial virulence factors: the cag pathogenicity island (PAI), for which CagA is a marker, and the vacuolating cytotoxin VacA. Several studies have shown the clinical relevance of the determination of IgG anti-CagA antibodies. OBJECTIVE: To assess the prevalence of vacA and cagA genotypes of H. pylori and the association with IgG anti-CagA antibodies in symptomatic patients. METHODS: We studied 50 patients (mean age 53 years, range 15-92). PCR amplification of the vacA s and m regions was performed using the primers described (J Biol Chem 1995; 270: 17771). For cagA PCR, primers described by Rugge et al. were used (Cancer 1999; 85: 2506) and determination of IgG anti-CagA antibodies was done according to the method described by Blaser and Perez (Cancer Res 1995; 55: 2111). RESULTS: All 50 patients studied were positive for H. pylori. Of the 50 H. pylori strains, 7 (14%) were isolated from patients with peptic ulcer disease and 43 (86%) from patients with non-ulcer dyspepsia. The most frequent vacA genotype was s2/m2, associated with cagA-H. pylori strains (p < 0.01). Presence of cagA+ H. pylori strains correlated with the presence of IgG antibodies (Kappa = 0.680). Determination of IgG anti-CagA antibodies showed a sensitivity of 77.4%, specificity of 94.7%, positive value of 96% and negative predictive value of 72%. CONCLUSIONS: The most frequent H. pylori genotype found in northeastern Mexico was vacA s2/m2, cagA-. The presence of this genotype correlated with the clinical presentations observed in these patients. In addition, CagA serology showed a great specificity and good sensitivity that allow us to use this assay to assess the prevalence of CagA+ strains in Mexico.

Prevención de la infección por el complejo Mycobacterium avium. ¿Una necesidad en nuestros pacientes con SIDA? / Prevention of infection due to Mycobacterium avium complex. A need in our AIDS patients?

Antecedentes: el complejo Mycobacterium avium (CMA) está compuesto por dos especies que poseen poca virulencia en el huésped normal, ya que la inmunidad celular da protección. Objetivo: conocer la frecuencia de la infección diseminada por el complejo Mycobacterium avium en nuestra población de pacientes con SIDA. Material y métodos: se estudiaron todos los pacientes que tuvieron cuadro clínico sugestivo y linfocitos CD4 < 200 células/mm3; también se les efectuó cultivo de médula ósea para procesarse en medio de Lowenstein Jensen. El grupo total estuvo constituido por 33 pacientes. Resultados: en ningún caso se aisló la micobacteria después de doce semanas de incubación. Dos enfermos (6 por ciento) fallecieron debido a sarcoma de Kaposi y otras infecciones oportunistas, y 31 individuos (94 por ciento) se encontraban en buenas condiciones después de seis meses de seguimiento. Conclusiones: la infección diseminada por el complejo Mycobacterium avium no es común en nuestro medio, por lo cual, al parecer, la profilaxis rutinaria no es imprescindible.

Identification of mycobacteria by mycolic acid pattern

Background. Tuberculosis caused by Mycobacterium tuberculosis is a public health problem which has increased in importance during the last 12 years, due in part to the increasing number of cases cuased by the association of acquired immunodeficiency syndrome (AIDS) and the appearance of multiple drug-resistant strains. Other mycobacteria which are often indistinguishable from tuberculosis have also increased. Methods. Mycolic acid patterns were obtained from 53 clinical isolated of sputum, cerebrospinal fluid, bronchial washing, corneal ulcer, and bone marrow, as well as from 11 acid-fast stain smear-positive clinical specimens. Standardized mycolic acid extraction method was used to ensure the maximal extraction of mycolic acid derivates to enhace the sensitivity of the method. A chromatographic column different from what others have employed and a different gradient elution from those reported in the literature were used, making a correlation between retention times of the chromatographic peaks obtained in this study and those previously reported for mycolic acid patterns from a strain of Mycobacterium avium necessary. Then, a comparison of retention times of mycolic acid pattern obtained in this study and those previously reported in the literature was carried out. Strains were identified as Mycobacterium tuberculosis complex, Mycobacterium avium complex, Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium kansasii in less than 24 hours. Results. In direct analysis of acid-fast stain smearpositive from 1+ to 4+ specimens, mycolic acid patterns were identified as Mycobacterium tuberculosis complex, Mycobacterium avium complex, Mycobacterium chelonae, and Mycobacterium kansasii, with a strong signal even in light 1+ positive samples. conclusions: The results showed that identification of mycobacteria through mycolic acid pattern is a rapid, sensitive, and very useful method for identification of mycobacteria in the early diagnosis of the mycobacteriosis

Seropositividad de la infección por HCV y HBV, en estudiantes universitarios del Estado de Nuevo León, México / Positive serology for HCV and HBV infection in univertity students of the state on Nuevo Leon, Mexico

Antecedentes: La hepatitis viral es una enfermedad infectocontagiosa. Los pacientes infectados con virus de la hepatitis B (HBV) o con virus de la hepatitis C (HCV) pueden evolucionar a un estado crónico sintomático o asintomático que ocasiona cirrosis y un riesgo muy alto de carcinoma hepático. Objetivo: Los sujetos asintomáticos portadores del antígeno de superficie del HBV (Hbs-Ag) o de anticuerpos dirigidos contra HCV son potencialmente infectantes, por lo que desde el punto de vista de salud pública, es muy importante detectarlos. Métodos: En este trabajo se buscó la frecuencia de seropositividad de HBs-Ag y de anticuerpos anti-HCV en una población de 774 jóvenes de nuevo ingreso a la Facultad de Medicina de la Universidad Autónoma de Nuevo León, con una edad promedio de 188 años. Para detectar HBs-Ag se usó una prueba de ELISA de segunda generación y una prueba confirmatoria de neutralización. Los anticuerpos anti-HCV se midieron por un ELISA de segunda generación y por una prueba confirmatoria de un inmunoensayo en línea o RIBA. Tesultados: Se detectaron tres sueros positivos en HBs-Ag por ELISA, y sólo un suero (0.13 por ciento de las muestras analizadas) se confirmó por neutralización. En cambio se obtuvieron 12 sueros con anticuerpos dirigidos contra HCV por ELISA, de los cuales 8 fueron confirmados por RIBA ( 1.03 por ciento de la población total analizada). Dos sueros positivos mostraron bandas de reactividad intensa y 6 dieron bandas de reactividad débil. Los 4 sueros negativos representan el 0.5 por ciento de falsos positivos de la prueba de ELISA para determinar anti-HCV. Conclusiones: En este estudio se encontró que la frecuencia de anticuerpos anti-HCV fue 7.95 veces más alta que la de HBs-Ag. Todos los sujetos seropositivos estaban asintomáticos, pero son considerados potencialmente infectantes. Este trabajo pone de manifiesto la necesidad de implantar en forma rutinaria las técnicas de detección de HBs-Ag y de los anticuerpos anti HCV, para poder establecer la prevalencia de estas enfermedades virales en nuestra región.