MercoPress. South Atlantic News Agency

Listerosis scare in Santiago's top private clinics and hospitals

Listeria monocytogenes

Several medical organisations from Chile requested this week the Public Health ministry declare a state of “sanitary alert” following an unprecedented increase in the number of cases of deadly bacteria identified as “Listeria Monocytogenes”, which is transmitted mainly through the food chain.

Doctor Luis Miguel Noriega member of the Chilean Infectology Society and resident of Santiago's Clinica Alemana said that the number of cases has jumped from three for the whole of 2007 to eleven last July. "Most patients infected are pregnant women and the rest immunocompromised cases", said Dr. Noriega. Researcher Katia Abarca from the University of Chile Molecular Infectology and Virology Lab confirmed Dr. Noriega's statement saying that several hospitals and clinics "simultaneously reported" cases of patients infected with the Listeria Monocitogenes bacteria and "the situation is under consideration by Chile's national health authorities". An investigation is ongoing to try and determine a possible common source of contagion of the different cases or if a progressive change of lifestyle habits could be influencing hygiene recommendations at the moment of preparing food. Dr. Abarca said that the main source of contagion is through contaminated food and warned that the bacteria are usually found in animal originated products or in contact with the soil. However in this particular outbreak what baffles researchers is the fact that most cases belong to the high income bracket of Santiago. Infectologist Ricardo Espinoza from the Clinica Las Condes who admitted that several cases have been reported in their facilities said "people must be very careful when consuming beef, chicken, turkeys, hot dogs, delicatessen such as blue cheese or camembert and all non pasteurized products". Noriega recommends, particularly pregnant women, avoiding consuming raw meat, sushi and prepared food from street outlets. "The best way to be on the safe side is to cook food at over 75 degrees Celsius and good hygiene manipulation". Dr. Abarca said contagion is only through food ingestion with the exception "of a pregnant mother to the baby". According to the US Food and Drug Administration the manifestations of listeriosis include septicemia, meningitis (or meningoencephalitis), encephalitis, and intrauterine or cervical infections in pregnant women, which may result in spontaneous abortion (2nd/3rd trimester) or stillbirth. The onset of the aforementioned disorders is usually preceded by influenza-like symptoms including persistent fever. It was reported that gastrointestinal symptoms such as nausea, vomiting, and diarrhea may precede more serious forms of listeriosis or may be the only symptoms expressed. Listeriosis Monocytogenes is defined as a Gram positive bacterium, motile by means of flagella. Some studies suggest that 1-10% of humans may be intestinal carriers of L. monocytogenes. It has been found in at least 37 mammalian species, both domestic and feral, as well as at least 17 species of birds and possibly some species of fish and shellfish. It can be isolated from soil, silage, and other environmental sources. L. monocytogenes is quite hardy and resists the deleterious effects of freezing, drying, and heat remarkably well for a bacterium that does not form spores. Most L. monocytogenes are pathogenic to some degree. The main target populations for listeriosis are: pregnant women/fetus - perinatal and neonatal infections; persons immunocompromised by corticosteroids, anticancer drugs, graft suppression therapy, AIDS; cancer patients - leukemic patients particularly; less frequently reported - diabetic, cirrhotic, asthmatic, and ulcerative colitis patients; the elderly; normal people--some reports suggest that normal, healthy people are at risk, although antacids or cimetidine may predispose. When listeric meningitis occurs, the overall mortality may be as high as 70%; from septicemia 50%, from perinatal/neonatal infections greater than 80%. In infections during pregnancy, the mother usually survives. Successful treatment with parenteral penicillin or ampicillin has been reported. Trimethoprim-sulfamethoxazole has been shown effective in patients allergic to penicillin. L. monocytogenes has been associated with such foods as raw milk, supposedly pasteurized fluid milk, cheeses (particularly soft-ripened varieties), ice cream, raw vegetables, fermented raw-meat sausages, raw and cooked poultry, raw meats (all types), and raw and smoked fish. FDA warns that its ability to grow at temperatures as low as 3°C permits multiplication in refrigerated foods.