Disminución en la frecuencia de infección por Helicobacter pylori en endoscopías digestivas altas / Helicobacter pylori infection detected during upper gastrointestinal endoscopy

Background: Helicobacter pylori (HP) is the most widespread chronic human infection worldwide and the most important pathogenic factor of gastric cancer. The calculated prevalence at the Clinical Hospital of the University of Chile from 2002 to 2005 was 44.9%. Aim: To determine the current prevalence of HP in patients undergoing an upper gastrointestinal endoscopy (UGI) and analyze its distribution according to age and endoscopic findings. Material and Methods: We reviewed 3.433 UGI performed during the year 2015, selecting those in which rapid urease test (RUT) was done. A positive RUT or a positive gastric biopsy (GB) were considered as HP infection. Results: RUT was done in 1862 UGI (55%) performed in patients aged 51 ± 17 years, (66% women). In 23% of these endoscopies, the RUT was positive. A GB was obtained 43% of endoscopies and 30% were positive for HP. In 105 patients the RUT was negative and the GB positive (rendering a 19.5% false negative rate). HP was detected by RUT and GB in 29% of endoscopies. The highest prevalence of infection (38.1%) was found between 40 and 49 years. HP infection had odds ratio of 4.24 for nodular gastropathy, 2.63 for gastric ulcer and 2.14 for duodenal ulcer (p < 0.05). Conclusions: HP prevalence in our center decreased significantly from 44.9% to 28.9% in 11 years. False negative RUT results may bias this finding. The use of proton pump inhibitors and antimicrobials that can interfere with the detection of HP should be registered to properly analyze the results of the RUT.

Serotipos de Pasteurella haemolytica en pulmones neumóticos de ovinos en México / Serotypes of Pasteurella haemolytica isolated from pneumonic sheeps in Mexico

Se investigó la distribución de los serotipos de Pasteurella haemolytica en pulmones neumónicos de ovinos en México. De un total de 860 pulmones neumónicos revisados, provenientes de 2 poblaciones de ovinos, se aislaron 120 cepas de P. haemolytica (14%). Las cepas aisladas fueron serotipificadas con los 12 antisueros monoespecíficos contra P. haemolytica, mediante la prueba de aglutinación rápida en placa. Los serotipos más comunes fueron el Al, A2, A5 y A9, representando el 22%, 16%, 11% y 7%, respectivamente. El 27% de los aislamientos (33 cepas) correspondió a cepas no tipificables. Al comparar las 2 poblaciones de ovinos muestreadas, se apreció que existieron diferencias en la frecuencia con que se aislaron los diferentes serotipos de P. haemolytica. Estos resultados deberán ser considerados en la elaboración de bactérias para prevenir la pasteurelosis pulmonar en ovinos; ya que éstas deben de contener los serotipos predominantes de la zona geográfica donde se pretende inmunizar a los ovinos