[An outbreak of Salmonella gastroenteritis among hospital workers]. / Brote por Salmonella enteritidis en trabajadores de un hospital.

OBJECTIVE: To describe and identify the causes of an outbreak of Salmonella enteritidis gastroenteritis that took place in June 1998, among tertiary care hospital workers, in Mexico City. MATERIAL AND METHODS: Cases were hospital workers who developed diarrhea or fever associated with gastrointestinal symptoms, after a meal at the hospital's dining room on June eight; controls were asymptomatic employees who also ate at the hospital's dining room on the same day. A food questionnaire was applied, and stool samples were obtained from all study subjects, including kitchen personnel. Blood cultures were practiced for febrile patients. Odds ratios with 95% confidence intervals (95% CI) and the chi-squared were used for statistical analysis. Statistical significance was set at p < 0.05. RESULTS: One-hundred-fifty-five workers developed symptoms, but only 129 (83.2%) answered the questionnaire; 150 controls were also studied. The most common symptoms were diarrhea (85%), abdominal pain (84%), cephalea (81.4%), nausea (78.3%), and chills (74.4%). Eight blood cultures were negative; 59 stool cultures (46%) from cases and six (4%) from controls, were positive for Salmonella enteritidis. Egg-covered meat was the suspected source of infection (OR 19.39, 95% CI 9.09-41.4); some other foodstuffs like fruit dessert and yogurt, were significantly more frequent in cases than in controls. Food cultures were all negative. CONCLUSION: This outbreak was probably caused by Salmonella-contaminated foodstuffs (egg-covered meat with potatoes) due to deficient cooking. This report shows the importance of food-quality programs for hospital meals.

Epidemiology of nosocomial outbreaks: 14-year experience at a tertiary-care center.

Twelve nosocomial outbreaks over 14 years at a tertiary-care center in Mexico are described. Overall mortality was 25.8%, one half due to pneumonia. The most common organism was Pseudomonas aeruginosa. Incidence was three outbreaks per 10,000 discharges; outbreak-related infections comprised 1.56% of all nosocomial infections. Incidence in the intensive care unit was 10-fold higher.

[Evaluation of a nosocomial infection surveillance program]. / Validación de un programa de vigilancia de infecciones nosocomiales.

OBJECTIVE: To validate the nosocomial infections surveillance system, establish its impact in morbi-mortality. MATERIAL AND METHODS: Surveillance of every single patient admitted during a one month period was done by one of us (DMG). Each possible case was discussed with two other hospital epidemiologists (SPLR, MSRF). This intensive surveillance was compared against the routinely surveillance performed by the nurses. We included all hospitalized patients between 11th July and 12th of August according to CDC (Atlanta, GA) nosocomial infections definitions. Patients were followed everyday and information about age, gender, underlying diagnosis, microorganisms responsible for nosocomial infections, hospital length of stay and mortality. RESULTS: During the study period 429 were admitted, 45 developed a nosocomial infection (cases) and 384 did not (controls). The incidence of nosocomial infections was 10.48 cases/100 discharges. The sensitivity and specificity of the surveillance system was 95.3 and 98.7%, respectively. Mortality in infected was 11.11% and in non infected was 2.4%. The average length of stay was 20 and 11 days for cases and non infected respectively (p < 0.01). Urinary tract infections were the most common NI (42%), secondary bacteremia (14 < or = %), pneumonia (11.11%) and deep surgical site infection (9.25%). The surgical wound infection rates were: 1.3%, 1.9% and 1.9% for clean, clean-contaminated and contaminated wounds. Patients with rapidly fatal diseases had an increased frequency of infections. The microorganisms most commonly isolated were Escherichia coli (28%), Staphylococcus aureus (11.11%), and Pseudomonas aeruginosa (8.6%). The level of antibiotic resistance was in average of 43% for those antibiotics tested. CONCLUSIONS: The sensitivity and specificity of the surveillance system was excellent. Patients with nosocomial infections had an increased length of stay and a higher mortality compared to those without NI. The validation of the surveillance system allows the production of trustable conclusions about nosocomial infections.

An epidemic outbreak of Malassezia folliculitis in three adult patients in an intensive care unit: a previously unrecognized nosocomial infection.

BACKGROUND: Malassezia is a lipophilic fungus commonly found in normal human skin. Infection of the hair follicle by Malassezia furfur occurs in patients with predisposing factors such as diabetes or immunosuppression, or who are undergoing antibiotic treatment. Malassezia furfur folliculitis is an infrequent nosocomial infection which may be associated with fomite transmission. METHODS: We reviewed the clinical files of three adult patients from an intensive care unit (ICU) who simultaneously developed folliculitis through Malassezia infection. We specifically analysed predisposing factors, possible transmission modes, characteristics of skin lesions, results of biopsies and cultures, treatment, and patient outcome. RESULTS: The three male patients were in neighboring beds and they all had factors that predisposed them to underlying immunosupression. Simultaneously, and within hours of each other, they developed erythematous follicular papules and pustules on the face and chest. The skin biopsies revealed an acute folliculitis with abundant round to oval yeasts of up to 5 microm in diameter. Stains for fungi (Schiff's peryodic acid, Grocott and silver methenamine) revealed numerous unipolar budding yeasts without hyphae, consistent with M. furfur. Conventional cultures were negative. The diagnosis of folliculitis by M. furfur was established and antifinigal treatment initiated, with adequate outcome of the dermatosis. After this outbreak, the aseptic and hygienic measures of the health care personnel of the ICU were reviewed and corrected. CONCLUSIONS: The simultaneous emergence of this superficial infection by M. furfur suggests fomite participation. This dermatomycosis is an infrequent nosocomial infection in adults, which to our knowledge has not been previously reported.

Salmonella gastroenteritis outbreak among workers from a tertiary care hospital in Mexico City.

OBJECTIVE: To describe an outbreak of Salmonella gastroenteritis among employees of the National Institute of Nutrition (INNSZ) of Mexico City during July, 1994. METHODS: Employees who developed diarrhea or fever associated with gastrointestinal symptoms starting on July 14th were included for study as well as 50 healthy controls. A questionnaire was applied to all, and they also provided a stool sample, along with other 80 asymptomatic people (included the kitchen workers) in whom only stool culture was done. RESULTS: Ninety-seven employees that ate regularly at the Hospital's cafeteria were affected by the outbreak, and 67 of them (69%) could be evaluated. Most of them were nurses (34%), and handymen (27%). Most common symptoms were abdominal pain (97%), diarrhea (95%), nausea (91%), and fever (89%). Cultures from suspicious food items were all negative, but stool cultures from 10/70 cases were positive for Salmonella enteritidis vs. 0/133 in the controls. The ten S. enteritidis isolates resulted identical either by serotyping and by rapid amplified polymorphic DNA (RAPD) analysis. Cultures from all kitchen employees were negative for S. enteritidis. Breakfast meal on July 14th was associated with the development of gastroenteritis (61/67 cases vs 26/50 controls, p < 0.001), and particularly with an egg-covered meat plate (61/62 vs 13/26 controls, p < 0.0001). CONCLUSIONS: This outbreak was probably caused by eggs contaminated with Salmonella, since no one of the kitchen personnel was found to be an asymptomatic carrier, and the implicated recipe allows for inappropriate cooking. Recommendations to improve cooking procedures must be added to the usual regulations to diminish the frequency of foodborne disease outbreaks in hospitals.