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Background: We report a meta-analysis of 4 identical time-series cohort studies of the impact of switching from use of open infusion containers (glass bottle, burette, or semirigid plastic bottle) to closed infusion containers (fully collapsible plastic containers) on central line-associated bloodstream infection (CLABSI) rates and all-cause intensive care unit (ICU) mortality in 15 adult ICUs in Argentina, Brazil, Italy, and Mexico., Methods: All ICUs used open infusion containers for 6-12 months, followed by switching to closed containers. Patient characteristics, adherence to infection control practices, CLABSI rates, and ICU mortality during the 2 periods were compared by χ(2) test for each country, and the results were combined using meta-analysis., Results: Similar numbers of patients participated in 2 periods (2,237 and 2,136). Patients in each period had comparable Average Severity of Illness Scores, risk factors for CLABSI, hand hygiene adherence, central line care, and mean duration of central line placement. CLABSI incidence dropped markedly in all 4 countries after switching from an open to a closed infusion container (pooled results, from 10.1 to 3.3 CLABSIs per 1,000 central line-days; relative risk [RR], 0.33 [95% confidence interval {CI}, 0.24-0.46]; P <.001). All-cause ICU mortality also decreased significantly, from 22.0 to 16.9 deaths per 100 patients (RR, 0.77 [95% CI, 0.68-0.87]; P <.001)., Conclusions: Switching from an open to a closed infusion container resulted in a striking reduction in the overall CLABSI incidence and all-cause ICU mortality. Data suggest that open infusion containers are associated with a greatly increased risk of infusion-related bloodstream infection and increased ICU mortality that have been unrecognized. Furthermore, data suggest CLABSIs are associated with significant attributable mortality.

Objective: To estimate the excess length of stay in an intensive care unit (ICU) due to a central line-associated bloodstream infection (CLABSI), using a multistate model that accounts for the timing of infection., Design: A cohort of 3,560 patients followed up for 36,806 days in ICUs., Setting: Eleven ICUs in 3 Latin American countries: Argentina, Brazil, and Mexico., Patients: All patients admitted to the ICU during a defined time period with a central line in place for more than 24 hours., Results: The average excess length of stay due to a CLABSI increased in 10 of 11 ICUs and varied from -1.23 days to 4.69 days. A reduction in length of stay in Mexico was probably caused by an increased risk of death due to CLABSI, leading to shorter times to death. Adjusting for patient age and Average Severity of Illness Score tended to increase the estimated excess length of stays due to CLABSI., Conclusions: CLABSIs are associated with an excess length of ICU stay. The average excess length of stay varies between ICUs, most likely because of the case-mix of admissions and differences in the ways that hospitals deal with infections.

Background: Hospitalized patients in critical care settings are at risk for bloodstream infections (BSI). Most BSIs originate from a central line (CL), and they increase length of stay, cost, and mortality. Open infusion containers may increase the risk of contamination and administration-related (CLAB) because they allow the entry of air into the system, thereby also providing an opportunity for microbial entry. Closed infusion containers were designed to overcome this flaw. However, open infusion containers are still widely used throughout the world.The objective of the study was to determine the effect of switching from open (glass, burettes, and semi-rigid) infusion containers to closed, fully collapsible, plastic infusion containers (Viaflex) on the rate and time to onset of central line-associated bloodstream infections CLABs., Methods: An open label, prospective cohort, active healthcare-associated infection surveillance, sequential study was conducted in four ICUs in Mexico. Centers for Disease Control National Nosocomial Infections Surveillance Systems definitions were used to define device-associated infections., Results: A total of 1,096 adult patients who had a central line in place for >24 hours were enrolled. The CLAB rate was significantly higher during the open versus the closed container period (16.1 versus 3.2 CLAB/1000 central line days; RR = 0.20, 95% CI = 0.11-0.36, P < 0.0001). The probability of developing CLAB remained relatively constant in the closed container period (1.4% Days 2-4 to 0.5% Days 8-10), but increased in the open container period (4.9% Days 2-4 to 5.4% Days 8-10). The chance of acquiring a CLAB was significantly decreased (81%) in the closed container period (Cox proportional hazard ratio 0.19, P < 0.0001). Mortality was statistically significantly lower during the closed versus the open container period (23.4% versus 16.1%; RR = 0.69, 95% CI = 0.54-0.88, P < 0.01)., Conclusions: Closed infusion containers significantly reduced CLAB rate, the probability of acquiring CLAB, and mortality.

Background: No information is available about the financial impact of central venous catheter (CVC)-associated bloodstream infection (BSI) in Mexico., Objective: To calculate the costs associated with BSI in intensive care units (ICUs) in Mexico City., Design: An 18-month (June 2002 through November 2003), prospective, nested case-control study of patients with and patients without BSI., Setting: Adult ICUs in 3 hospitals in Mexico City., Patients and Methods: A total of 55 patients with BSI (case patients) and 55 patients without BSI (control patients) were compared with respect to hospital, type of ICU, year of hospital admission, length of ICU stay, sex, age, and mean severity of illness score. Information about the length of ICU stay was obtained prospectively during daily rounds. The daily cost of ICU stay was provided by the finance department of each hospital. The cost of antibiotics prescribed for BSI was provided by the hospitals' pharmacy departments., Results: For case patients, the mean extra length of stay was 6.1 days, the mean extra cost of antibiotics was US dollars 598, the mean extra hospital cost was US dollars 11,591, and the attributable extra mortality was 20%., Conclusions: In this study, the duration of ICU stay for patients with central venous catheter-associated BSI was significantly longer than that for control patients, resulting in increased healthcare costs and a higher attributable mortality. These conclusions support the need to implement preventive measures for hospitalized patients with central venous catheters in Mexico.

Background: Nosocomial infections increase mortality and costs in the intensive care units; however, few studies have addressed organ failure that developed in infected patients and their overall costs. The goal of this study was to measure the frequency of organ failure in nosocomial infection and the mortality and costs of these in critical care areas., Methods: This was a nested 1:2 case-control study in a cohort of all consecutively hospitalized patients comparing those with and without nosocomial infections over a year in an institutional intensive care unit (ICU). Those patients who acquired an infection during hospitalization were considered cases. Controls were matched by hospital stay at least as long as the cases' time acquisition of nosocomial infection, age +/-5 years and APACHE II +/-5 points., Results: Forty-three patients developed at least one nosocomial infection event (cases). The matching success was about 94%. Higher frequency and duration of organ failures was observed in the cases, as well as the number of devices and procedures (p < 0.05). Attributable mortality was 16.3% (p < 0.001). Attributable total cost of a nosocomial infection acquired in the ICU was 12,155 dollars., Conclusions: Nosocomial infection acquired in the ICU increases length of stay, frequency and duration of organ failures, mortality, and costs.

Sepsis definitions help to understand and to better define a group of syndromes secondary to an infectious insult. The hierarchical continuum of inflammatory response leads, in absence of counterregulatory forces, to organ damage and death. We have learned first the response to treatment and afterwards the pathophysiology behind it. This lesson has, of course, not always been followed by a reduction of mortality. The definition, natural history, risk factors, diagnoses, and treatment based on emerging evidence will help to improve patient outcomes and mortality. Standardized care seems to improve survival, and validation and further evaluation of this care is necessary to maximize resources and outcomes.

Background: The ESAT-6 antigen from Mycobacterium tuberculosis evokes a protective immune response in murine models and is widely recognized by tuberculosis patients (TB) and healthy household contacts (HHC). However, little is known about human immune response to this antigen in populations from areas of high endemicity. This study aimed to determine the capacity of T-cells from a group of TB patients and HHC for cell proliferation and production of cytokines type Th1 or Th2 (IL-4, IL-10, and IFN-gamma) and to identify total IgG reactivity to the recombinant protein rESAT-6 and five overlapping synthetic peptides as well as to r38 kDa and two peptides., Methods: T-cells from nine TB patients and nine HHC were stimulated with rESAT-6 and five overlapping synthetic peptides, previously selected from a set of 21 peptides and each of 16 amino acids in length (P1, P4, P6, P8, and P20). Similar experiments were carried out with r38 kDa and two peptides of 20 amino acids in length (38G and 38K). Cytokines in supernatants and total IgG from serum were determined by ELISA., Results: Stimulation index (SI) was highest in HHC to rESAT-6 and peptides P1, P8, and P20. Differences in response to 38 kDa and 38G peptide between TB patients and HHC were not demonstrated. Cytokines from T-cell cultures were tested with a resulting SI=3.0. IFN-gamma was produced predominantly in HHC to rESAT-6, P8, and P20, while in TB patients production of IL-10 was detected in relation to r38 kDa. IL-4 was detected in minimal amounts in both groups. IgG from TB patients was predominantly recognized in connection with rESAT-6 and the P4 peptide, with an important response against r38 kDa detected in HHC., Conclusions: ESAT-6 recognition by HHC could indicate that these responses represent possible early-stage infections.

Objective: To describe the results of the Nosocomial Infection surveillance program at the Cardiology Hospital in Centro Médico Nacional Siglo XXI of the Mexican Social Security Institute., Methodology: To inform of the epidemiologic follow-up results from January 2000 to July 2003. Global frequency, infection rates by infection site, hospital services, and frequency of most common microorganisms were estimated., Results: During this period, global incidence showed that in every 100 discharges, there were 4.3 infections (4.3/100). Frequency of infection was slightly higher in the surgical intensive care unit. Average infection rate in lower respiratory tract infections was 27/1,000; in surgical-site infections: 8/1,000 (mediastinitis 0.8/1,000); it was found that in urinary tract infection, rate was 6.6/1,000. Most commonly isolated microorganisms were: coagulase-negative Staphylococcus (25%), Enterobacter sp. (17%), Candida albicans (13%), S. aureus (9%), P. aeruginosa (9%) and K. pneumoniae (6%)., Conclusion: This study describes the epidemiology of nosocomial infections in a Cardiology Hospital. The information is obtained through epidemiologic follow-up programs. This information is very important to develop specific strategies for control of infections.

Transmissible spongiform encephalopathies (TSE) are a group of diseases which have received a lot of attention in recent years. The interest on these diseases has been stimulated by the appearance of bovine spongiform encephalopathy (BSE) and the new variant of Creutzfeldt-Jakob disease (nvCJD); the latter is likely to be acquired by ingesting contaminated beef. Until now 109 cases of nvCJD have been reported, most of them occurring in the United Kingdom. Some experts think that this is the beginning of a nvCJD pandemic. Deep knowledge of the mechanisms of transmission of TSE is needed to prevent the emergence of a TSE pandemic in humans. We address various aspects of TSE and discuss prevention methods of TSE in ruminants and humans.

Unlabelled: The vulnerability of human populations to chemical, biological, radiological, and nuclear terrorism has been widely discussed but insufficiently studied. Current public health policies are not guided by solid and relevant information to design cost-effective programs for preventing or controlling this kind of incidents in the future. Governmental budgets are insufficient to respond to bioterrorist attacks. To face these threats, developing countries like Mexico should frame strategies and devise specific preventive actions that consider the transmission dynamics of potential infectious agents likely to be used in a bioterrorist attack., Proposals: The international reaction to a biological attack must be supported by international agreements that ban the use of biological agents for warfare and/or defense purposes, as well as on academic and technological exchange for the prevention of bioterrorist attacks. At the national level, the recommendations in the event of a biological attack are: a) establishing a legal defense strategy against bioterrorism; b) implementing education programs as a key strategy for defense against bioterrorism; c) devising a national program of interinstitutional anti-bioterrorist coordination that includes medical emergency assistance and collection of medical forensic evidence; d) including a biological weapon registry in epidemiological surveillance systems; e) implementing a laboratory for biological material analysis related to terrorist incidents; f) devising public health information campaigns, g) assuring the supply of diagnostic testing, special protection, and emergency treatment materials; h) decentralizing alert systems for the timely detection of bioterrorist attacks; i) responding to bioterrorist actions addressed against animals and plants, and j) organizing Ethics Committees in case of urgent events derived from a biological attack., Conclusions: The proper response to sudden and unexpected events of emergent or unusual infectious diseases involved in a bioterrorist attack requires an adequate public health infrastructure. Modern technology allows the timely identification of multiple infectious agents by nucleic acid analyses and should be widely available in reference laboratories. All these measures require sufficient funding to respond to this potential threat. Resource allocation to respond to bioterrorist attacks must be consonant with their potential public health consequences.

Objective: To compare the performance of three purified protein derivative (PPD) formulations: Tubersol (Connaught); RT23, Statens Serum Institut (SSI); and RT23, Mexico, tested in Mexican populations at low and high risk for tuberculosis (TB)., Design: A double-blinded clinical trial., Setting: A university hospital in Mexico City., Participants: The low-risk population was first or second-year medical students with no patient contact; the high-risk population was healthcare workers at a university hospital., Methods: Each of the study subjects received the three different PPD preparations. Risk factors for TB, including age, gender, occupation, bacille Calmette-Guérin (BCG) status, and TB exposure, were recorded. A 0.1-mL aliquot of each preparation was injected in the left and right forearms of volunteers using the Mantoux technique. Blind readings were done 48 to 72 hours later. Sensitivity and specificity were calculated at 10 mm of induration using Tubersol as the reference standard. The SSI tested the potency of the different PPD preparations in previously sensitized guinea pigs., Results: The low-risk population had a prevalence of positive PPD of 26%. In the low-risk population, RT23 prepared in Mexico, compared to the 5 TU of Tubersol, had a sensitivity of 51%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 86%. The RT23 prepared at the SSI had a sensitivity of 69%, a specificity of 99%, a positive predictive value of 95%, and a negative predictive value of 90%. In the high-risk population, the prevalence of positive PPD was 57%. The RT23 prepared in Mexico had a sensitivity of 33%, a specificity of 100%, and a positive predictive value of 53%; the RT23 prepared at the SSI had a sensitivity of 91%, a specificity of 98%, a positive predictive value of 98%, and a negative predictive value of 89%. RT23 used in Mexico had a potency of only 23% of that of the control. There was no statistical association among those with a positive PPD, irrespective of previous BCG vaccination (relative risk, 0.97; 95% confidence interval, 0.76-1.3;P=.78)., Conclusions: Healthcare workers had twice the prevalence of positive PPD compared to medical students. RT23 prepared in Mexico had a low sensitivity in both populations compared to 5 TU of Tubersol and RT23 prepared at the SSI. Previous BCG vaccination did not correlate with a positive PPD. Low potency of the RT23 preparation in Mexico was confirmed in guinea pigs. Best intentions in a TB program are not enough if they are not followed by high-quality control.

To assess risk factors for development of candidal blood stream infections (CBSIs), a prospective cohort study was performed at 6 sites that involved all patients admitted to the surgical intensive care unit (SICU) for >48 h over a 2-year period. Among 4276 such patients, 42 CBSIs occurred (9.82 CBSIs per 1000 admissions). The overall incidence was 0.98 CBSIs per 1000 patient days and 1.42 per 1000 SICU days with a central venous catheter in place. In multivariate analysis, factors independently associated with increased risk of CBSI included prior surgery (relative risk [RR], 7.3), acute renal failure (RR, 4.2), receipt of parenteral nutrition (RR, 3.6), and, for patients who had undergone surgery, presence of a triple lumen catheter (RR, 5.4). Receipt of an antifungal agent was associated with decreased risk (RR, 0.3). Prospective clinical studies are needed to identify which antifungal agents are most protective and which high-risk patients will benefit from antifungal prophylaxis.

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.

Background: Our objective was to evaluate survival trends (1984-1995), the prevalence of AIDS-defining conditions, and the role of treatment with zidovudine and/or prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) in survival following AIDS diagnosis., Methods: We reviewed the clinical charts and postmortem studies of all patients admitted to the HIV Clinic from 1984-1995. Three groups were identified according to the following dates of HIV diagnosis: 1) 1984-1988; 2) 1989-1992, and 3) 1993-1995., Results: We studied 909 charts. During the study period, 744 (81.6%) patients developed AIDS. Median survival increased from 11.7 months in group 1 to 15.4 and 17.5 months in groups 2 and 3, respectively (p <0.05). We observed the following important changes in the frequency of AIDS-defining conditions over the study period: Pneumocystis carinii pneumonia (PCP) decreased from 24.8 to 17 and 14% in groups 1, 2, and 3, respectively, (p = 0.008), and Kaposi's sarcoma (KS), from 31.1 to 10.5 and 13.5% (p <0.001). On the other hand, there was an increase in cytomegalovirus disease with 12.4, 20.4, and 18.6% (p = 0.04) and wasting syndrome with 36, 45, and 57% (p <0.001). In the proportional hazard model for death, zidovudine or TMP-SMX use was associated with a protective effect., Conclusions: Survival is improving among patients with HIV infection at our institution. The prevalence of AIDS-defining conditions has changed over the last 12 years. There has been a diminution of PCP and KS, whereas cases of CMV disease and wasting syndrome increased.

The frequency of hepatitis C (HCV), hepatitis B (HBV), human immunodeficiency virus (HIV), and human T-cell lymphotropic virus (HTLV) I/II was determined in the emergency room of a teaching hospital. Of 909 patients, 19% had at least one infection; 7.8% had HCV, 6.9% HBV, 3.3% HIV, and 2.8% HTLV I/II. The probability that a healthcare worker would have an accident with an infected patient and seroconvert was 4.99 to 24.9 per 100,000 venipunctures for HBV, 5.6 to 8.4 for HCV, and 0.12-0.16 for HIV in our emergency room.

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.

Objective: To determine the 1-day prevalence of community-acquired, hospital-acquired, or intensive care unit (ICU)-acquired infections in Mexican ICUs. To identify associated risk factors, predominant infecting organisms, and mortality rates., Design: A 1-day point-prevalence study., Setting: A total of 254 adult ICUs in Mexico., Patients: Adult patients hospitalized in the participating ICUs., Results: A total of 895 patients were studied, of whom 521 patients (58.2%) were infected. Community-acquired infection occurred in 214 patients (23.9%), non-ICU nosocomial infection occurred in 99 patients (11.1%), and 208 patients had at least one ICU-acquired infection (23.2%; 1.45 episodes/patient). The most frequently reported ICU-acquired infections were pneumonia (39.7%), urinary tract infections (20.5%), wound infection (13.3%), and bacteremia (7.3%). The mortality rate for the ICU-acquired infections after 6 wks of follow-up was 25.5%. Multivariate regression analysis showed the following risk factors for ICU-acquired infections: neurologic failure as a primary cause of admission (odds ratio [OR], 1.697; 95% confidence interval [CI], 1.001-2.839); length of stay in ICU (OR, 1.119; 95% CI, 1.091-1.151); number of therapeutic and/or diagnostic interventions during the preceding week (OR, 1.118; 95% CI, 1.016-1.231); peripherally administered infusion of hyperosmolar solutions (OR, 6.93; 95% CI, 2.452-21.661); sedative usage in the preceding week (OR, 1.751; 95% CI, 1.183-2.602); history of an emergency surgery in the preceding month (OR, 1.875; 95% CI, 1.251-2.813). The administration of antimicrobial treatment if there was an infection decreased the risk of death (OR, 0.406; 95% CI, 0.204-0.755)., Conclusions: Evidence of a high frequency of nosocomial infections was found, and potential risk factors for acquiring infections and mortality were identified. Mortality rates according to the hierarchy of the systemic inflammatory response syndrome in Latin American ICUs are reported.

Objective: To describe tuberculosis surveillance results among healthcare workers of a tertiary care center., Material and Methods: All medical records of workers from 1992-1998 were reviewed. Demographics, labor, medical history, previous testing, PPD, booster shots and follow-up were analyzed. Statistical analysis was performed with odds ratios, p-values, and 95% confidence intervals. Subgroup analysis were done with chi 2. Kaplan-Meier estimates were used to analyze times to conversion., Results: Surveillance was done in 1617 workers (68% female and 32% male). Mean age was 26.9 +/- 7.6 (15-68) years. Job positions were 30.5% nurses, 14.6% residents and 14.1% interns. Place of origin was Mexico City in 65.8%. BCG vaccination was present in 71.6% and 15.1% had previous PPD. Admission PPD was positive in 39.6%, negative in 48.3% and 12.1% were lost to follow-up. On negatives, 483 booster shots were applied, and 49 additional positives were found. Follow-up was done in 231 workers, of which 100 (43.3%) converted. The mean time for conversion was 22.8 +/- 12.4 months. The conversion rate at twelve months was 20%. Fifty workers received/accepted isoniazid prophylaxis., Conclusions: A high percentage of workers were PPD-positive; booster shots allowed the detection of an additional 10%. A high conversion rate underscores the need to organize tuberculosis control programs in Mexico.

Objective: To describe the molecular epidemiology of Legionella pneumophila infections in the University of Iowa Hospitals and Clinics (UIHC)., Design: Molecular epidemiological study using pulsed-field gel electrophoresis (PFGE)., Setting: A large university teaching hospital. ISOLATES: All surviving isolates obtained from culture-proven nosocomial L. pneumophila infections and all surviving isolates obtained from the University of Iowa Hospital and Clinics' water supply between 1981 and 1993., Results: Thirty-three isolates from culture-proven nosocomial cases of L. pneumophila pneumonia were available for typing. PFGE of genomic DNA from the clinical isolates identified six different strains. However, only strain C (16 cases) and strain D (13 cases) caused more than 1 case. Strain C caused clusters of nosocomial infection in 1981, 1986, and 1993 and also caused 4 sporadic cases. Strain D caused a cluster in 1987 and 1988 plus 4 sporadic cases. Of the six strains causing clinical infections, only strains C and D were identified in water samples. PFGE identified three strains in the water supply, of which strains C and D caused clinical disease and also persisted in the water supply during most of the study period., Conclusion: Specific strains of L. pneumophila can colonize hospital water supplies and cause nosocomial infections over long periods of time.

Computer-assisted DNA fingerprinting with the complex probe Ca3 has been used to analyze the relatedness of isolates collected from individuals with nosocomial bloodstream infections (BSIs) and hospital care workers (HCWs) in the surgical and neonatal intensive care units (ICUs) of four hospitals. The results demonstrate that for the majority of patients (90%), isolates collected from commensal sites before and after collection of a BSI isolate were highly similar or identical to the BSI isolate. In addition, the average similarity coefficient for BSI isolates was similar to that for unrelated control isolates. However, the cluster characteristics of BSI isolates in dendrograms generated for each hospital compared to those of unrelated control isolates in a dendrogram demonstrated a higher degree of clustering of the former. In addition, a higher degree of clustering was observed in mixed dendrograms for HCV isolates and BSI isolates for each of the four test hospitals. In most cases, HCW isolates from an ICU were collected after the related BSI isolate, but in a few cases, the reverse was true. Although the results demonstrate that single, dominant endemic strains are not responsible for nosocomial BSIs in neonatal ICUs and surgical ICUs, they suggest that multiple endemic strains may be responsible for a significant number of cases. The results also suggest that cross-contamination occurs between patients and HCWs and between HCWs in the same ICU and in different ICUs. The temporal sequence of isolation also suggests that in the majority of cases HCWs are contaminated by isolates from colonized patients, but in a significant minority, the reverse is true. The results of this study provide the framework for a strategy for more definitive testing of the origins of Candida albicans strains responsible for nosocomial infections.

Candida species are the fourth most frequent cause of nosocomial bloodstream infections, and 25%-50% occur in critical care units. During an 18-month prospective study period, all patients admitted for > or = 72 hours to the surgical (SICUs) or neonatal intensive care units (NICUs) at each of the participant institutions were followed daily. Among 4,276 patients admitted to the seven SICUs in six centers, there were 42 nosocomial bloodstream infections due to Candida species (9.8/1,000 admissions; 0.99/1,000 patient-days). Of 2,847 babies admitted to the six NICUs, 35 acquired a nosocomial bloodstream infection due to Candida species (12.3/1,000 admissions; 0.64/1,000 patient-days). The following were the most commonly isolated Candida species causing bloodstream infections in the SICU: Candida albicans, 48%; Candida glabrata, 24%; Candida tropicalis, 19%; Candida parapsilosis, 7%; Candida species not otherwise specified, 2%. In the NICU the distribution was as follows: C. albicans, 63%; C. glabrata, 6%; C. parapsilosis, 29%; other, 3%. Of the patients, 30%-50% developed incidental stool colonization, 23% of SICU patients developed incidental urine colonization, and one-third of SICU health care workers' hands were positive for Candida species.

As a result of better understanding of pathogenesis, new definitions of sepsis have been proposed, and the complexity of this syndrome is clearer. Population-based studies of bloodstream infections--what now is called sepsis--have helped us to understand the natural history of this very frequent problem. The mortality and morbidity of each of the systemic inflammatory response syndrome stages have been described; our ability to better understand and predict these stages will help us to make better therapeutic decisions.

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.

The main objective of a hospital-acquired infections control program is to decrease the risk of acquisition and the morbidity and costs associated. The organization of a team with technical and humanistic leadership is essential. Every infection control program must also develop strategies that allow: a) identification of the problems, b) to establish the importance of each one, c) to determine their causes, d) to develop solutions and e) the evaluation of the recommended solutions. The development of technical and humanistic abilities by the leader and the members of the team, and the use of the tools mentioned above have produced the only validate and highly effective program of quality improvement in the hospital.

Objective: To know the trend of nosocomial infections rates at a third level hospital since the beginning of the infection control program until the present and to evaluate the impact in mortality and length of hospital stay., Material and Methods: A study descriptive, retrospective and retrolective was done in a reference hospital providing tertiary care in Mexico City. Recorded data included rates, type of nosocomial infections and distribution of nosocomial infections from the database of Hospital Epidemiology Division between 1991 to 1996. In every patient the degree of severity disease was evaluated according to the McCabe-Jackson's scale, we also collected age and the length of stay. Statistical analysis was done with chi 2 test for tendencies of different evaluated parameters. This study was divided in three periods: before remodel (1991-1993), to remodel (1994-1995) and after remodel (1996). Compared the before remodel period against after remodel period., Results: In the study period, mean nosocomial infections ratio was of 8.6 by 100 discharges, showing a decrease of 20% (p < 0.01). Hospital area with the highest infections rate was ICU (26.9 by 100 discharge), followed by general ward of hospitalization with shared rooms (9.47) and private rooms (7.5). Urinary tract infections was the most frequent (26.6%), followed by surgical wound infection (24.4%), pneumonia (12.1%) and primary bacteremia (9.5%). Rates of urinary tract infections and primary bacteremias had decreased significantly (p < 0.05 and p < 0.00001 respectively), while surgical wound infections and pneumonias increased (p < 0.005 and p < 0.00001 respectively). Associated mortality diminished in 36% (p < 0.00001). The length of stay diminished 42.8%. There was not differences in the severity of disease along this period., Conclusions: Since the establishment of the nosocomial infections surveillance and control program at the INNSZ on 1985, nosocomial infections rate (56%) and the associated mortality (36%) have diminished. These changes are consequence of the establishment of a nosocomial infections control program and the decrease of length of stay and does not seems to be related to the age or to the severity of the disease of the hospitalized patients.

We conducted a 9-month prospective cohort study of 2,527 patients with systemic inflammatory response syndrome in three intensive care units and three general wards in a tertiary health care institution. Markov models were developed to predict the probability of movement to and from more severe stages--sepsis, severe sepsis, or septic shock--at 1, 3, and 7 days. For patients with sepsis, severe sepsis, and septic shock, the probabilities of remaining in the same category after 1 day were .65, .68, and .61, respectively. The probability for progression after 1 day was .09 for sepsis to severe sepsis and .026 for severe sepsis to shock. The probability of patients with sepsis, severe sepsis, and septic shock dying after 1 day was .005, .009, and .079, respectively. The model can be used to predict the reduction in end organ dysfunction and mortality with use of increasingly effective antisepsis agents.

The National Epidemiology of Mycoses Survey (NEMIS) involves six academic centers studying fungal infections in surgical and neonatal intensive care unit (ICU) patients. We studied variation in species and strain distribution and anti-fungal susceptibility of 408 isolates of Candida spp. Candida spp. were isolated from blood, other normally sterile site cultures, abscesses, wounds, catheters, and tissue biopsies of 141 patients hospitalized in the surgical (107 patients) and neonatal (34 patients) ICUs of medical centers located in Oregon, Iowa, California, Texas, Georgia, and New York. Isolates were also obtained from selected colonized patients (16 patients) and the hands of health care workers (27 individuals). DNA typing was performed using pulsed field gel electrophoresis, and antifungal susceptibility to amphotericin B, 5-fluorocytosine, fluconazole, and itraconazole was determined using National Committee for Clinical Laboratory Standards (NCCLS) methods. Important variation in susceptibility to itraconazole and fluconazole was noted: MICs of itraconazole ranged from 0.25 microgram/mL (MIC90) in Texas to 2.0 micrograms/mL (MIC90) in New York. Similarly, the MIC90 for fluconazole was higher for isolates from New York (64 micrograms/mL) compared to the other sites (8-16 micrograms/mL). In general, DNA typing revealed patient-unique strains; however, there were 13 instances of possible cross-infection noted in 5 of the medical centers. Notably, 9 of the 13 clusters involved species of Candida other than C. albicans. Potential transmission from patient-to-patient (C. albicans, C. glabrata, C. tropicalis, C. parapsilosis) and health care worker-to-patient (C. albicans, C. parapsilosis, C. krusei) was noted in both surgical ICU and neonatal ICU settings. These data provide further insight into the epidemiology of nosocomial candidiasis in the ICU setting.

Objective: Define the epidemiology of the four recently classified syndromes describing the biologic response to infection: systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, and septic shock., Design: Prospective cohort study with a follow-up of 28 days or until discharge if earlier., Setting: Three intensive care units and three general wards in a tertiary health care institution., Methods: Patients were included if they met at least two of the criteria for SIRS: fever or hypothermia, tachycardia, tachypnea, or abnormal white blood cell count., Main Outcomes Measures: Development of any stage of the biologic response to infection: sepsis, severe sepsis, septic shock, end-organ dysfunction, and death., Results: During the study period 3708 patients were admitted to the survey units, and 2527 (68%) met the criteria for SIRS. The incidence density rates for SIRS in the surgical, medical, and cardiovascular intensive care units were 857, 804, and 542 episodes per 1000 patient-days, respectively, and 671, 495, and 320 per 1000 patient-days for the medical, cardiothoracic, and general surgery wards, respectively. Among patients with SIRS, 649 (26%) developed sepsis, 467 (18%) developed severe sepsis, and 110 (4%) developed septic shock. The median interval from SIRS to sepsis was inversely correlated with the number of SIRS criteria (two, three, or all four) that the patients met. As the population of patients progressed from SIRS to septic shock, increasing proportions had adult respiratory distress syndrome, disseminated intravascular coagulation, acute renal failure, and shock. Positive blood cultures were found in 17% of patients with sepsis, in 25% with severe sepsis, and in 69% with septic shock. There were also stepwise increases in mortality rates in the hierarchy from SIRS, sepsis, severe sepsis, and septic shock: 7%, 16%, 20%, and 46%, respectively. Of interest, we also observed equal numbers of patients who appeared to have sepsis, severe sepsis, and septic shock but who had negative cultures. They had been prescribed empirical antibiotics for a median of 3 days. The cause of the systemic inflammatory response in these culture-negative populations is unknown, but they had similar morbidity and mortality rates as the respective culture-positive populations., Conclusions: This prospective epidemiologic study of SIRS and related conditions provides, to our knowledge, the first evidence of a clinical progression from SIRS to sepsis to severe sepsis and septic shock.

In order to determine the potential for cross-transmission of Candida spp. between health-care workers and patients, the survival of clinical isolates of five species of Candida on the palms of human volunteers was tested. One hundred microliters of a McFarland 1.0 density suspension (5 x 10(5) cfu) from an overnight culture of Candida albicans, Candida krusei, Candida parapsilosis, Candida tropicalis and Candida glabrata was used as inoculum. The degree of hydrophobicity of the different Candida species was also tested and did not influence the survival. The half-lives were brief, being 9.5, 12.4, 7.4, 12.8, 9.6 min for Candida albicans, Candida krusei, Candida glabrata, Candida parapsilosis, and Candida tropicalis, respectively, but at 45 min 2.6 x 10(3) to 3 x 10(4) organisms remained on the hands. Survival of Candida albicans for as long as 24 h on inanimate surfaces was observed. Transmission from one hand to a second hand occurred in 69% of the experiments and from the first to a third hand in 38%. Transmission to and from inanimate surfaces was successful in most of the experiments (90%). This experimental model aids in the biological study of Candida spp. and suggests some of the potential mechanisms of transmission.

Thorough counseling with emphasis on the importance of mosquito bite avoidance, as well as on compliance with prophylactic antimalarial regimens, remains an important task for the physician preparing a patient for international travel. Chloroquine continues to be the drug of choice for prophylaxis in areas not reporting chloroquine resistance. Otherwise, mefloquine is the first-line agent. Under special circumstances, alternatives to mefloquine can be employed and include doxycycline or proguanil plus chloroquine.