APACHE II and ISS scores as predictors of nosocomial infections in trauma patients.

BACKGROUND: Nosocomial infections affect more than 2 million patients annually in the United States at a cost of $4.5 billion. The aim of this study is to identify the role of the APACHE II score and the Injury Severity Scale (ISS) as independent predictors of nosocomial infections in trauma patients admitted to the intensive care unit (ICU). METHODS: A retrospective chart review of 113 trauma patients admitted to the ICU was conducted by an infectious disease physician. Demographic data and incidence of nosocomial infections were recorded. Multivariate logistic regression analysis was used to determine variables that are predictive of the occurrence of nosocomial infections. RESULTS: Presence or absence of intubation, ICU length of stay, APACHE II score, and ISS were related to the presence of infections; however, only the ICU length of stay was an independent predictor of a nosocomial infection, with an odds ratio of 1.81. By linear regression, 17% of the variance in the ICU duration of stay was a result of the APACHE II score in patients with a score >/=5. CONCLUSION: APACHE II score and ISS score were not good predictors of the incidence of nosocomial infections in trauma patients admitted to the ICU, but the APACHE II score has a modest correlation with the duration of stay in the ICU. A stratified cohort study could identify the subset of patients for which the APACHE II score predicts a prolonged stay in the ICU, thus an increased risk of infection.

Stenotrophomonas maltophilia infection and colonization in the intensive care units of two community hospitals: A study of 143 patients.

STUDY OBJECTIVE: To study the epidemiology of Stenotrophomonas maltophilia infections in the intensive care units (ICUs) of community general hospitals. DESIGN: Retrospective chart review of 143 patients with cultures positive for S. maltophilia over a 2-year period. SETTING: Intensive care units of 2 community general hospitals. RESULTS: Patients with S. maltophilia infection or colonization were elderly (mean age 62.4 years), intubated for a mean of 11.8 days, and had a mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score of 16.6. A tracheostomy was present in 22.4%, and underlying chronic respiratory disease and malignancy were found in 25.9% and 15.4%, respectively. Only 2 patients (1.4%) were neutropenic. Most isolates (89.5%) were from the respiratory tract and were part of a polymicrobial culture in 52. 5% of patients. Only a slightly higher APACHE II score (mean = 18.0, SD 7.8 vs mean = 15.6, SD 6.2, P = 0.052) differentiated patients with infection from those with colonization. All but 2 patients were exposed to antibiotics before their positive culture. Crude mortality rate was 41.3% overall and was significantly higher in those with an APACHE II score of 15 or more (48.8% vs 30.5%, P = 0. 028). CONCLUSION: S. maltophilia is emerging as an important cause of nosocomial infection, especially pneumonia, in ICUs of community general hospitals. Patients tend to be elderly, intubated for a mean of about 12 days, have high APACHE II scores, and frequently have a tracheostomy or underlying chronic respiratory disease. In contrast to earlier reports, neutropenia and underlying malignancy are uncommon in our ICU population. We found prior antibiotic exposure was almost universal and similar to previous reports, but use of imipenem was much less common in our community hospital patients. Patients with a high APACHE II score should be considered infected rather than colonized, but differentiation of infection from colonization remains problematic. Isolation of S. maltophilia from a patient carries a crude mortality rate of 41.3%, and patients with an APACHE II score of 15 or more have a significantly higher mortality rate than those with lesser scores, approaching 50%. Trimethoprim-sulfamethoxazole (TMP-SMX) remains the drug of choice for infections caused by S. maltophilia.

Gonorrhea. Finding and treating a moving target.

Gonorrhea is the most common reportable disease in the United States. In recent years, the epidemiology of this infection has changed as a result of increasing drug abuse, exchange of money and drugs for sex, and sexual promiscuity among teenagers, particularly blacks. Significant numbers of asymptomatic male carriers have been identified, which presents an additional challenge to disease control. Gonococcal infection has become increasingly resistant to traditional antibiotic therapy and now requires the use of newer, more expensive agents. Single-dose oral treatment with cefixime (Suprax) or a quinolone appears to be effective, safe, and practical for patients with uncomplicated gonorrhea. Serious infection and new syndromes caused by gonococci continue to be reported. Because disseminated infections can be fatal, hospitalization and treatment with intravenous antibiotics such as ceftriaxone sodium (Rocephin) or cefotaxime sodium (Claforan) are required.

Anaerobic wound infection: Bacteroides mediastinitis after cardiovascular surgery.

A case of postoperative anaerobic mediastinitis after coronary artery bypass grafting is reviewed. One of the causative organisms, Bacteroides oralis, has never previously been described as a pathogen causing mediastinitis after median sternotomy incision. There was associated Bacteroides fragilis bacteremia. Only three cases of Bacteroides species mediastinitis after open heart surgery have been reported. This anaerobic bacterium remains a rare pathogen in median sternotomy infections despite the increasing number of cases of mediastinitis seen in association with the burgeoning number of patients undergoing cardiac surgery. Multiple risk factors may contribute to mediastinal infections, which occur in about 2% of patients undergoing coronary artery surgery. When infection occurs, aerobic and anaerobic wound cultures should be made and appropriate antimicrobial and surgical therapy instituted.

Multicenter collaborative evaluation of a standardized serum bactericidal test as a predictor of therapeutic efficacy in acute and chronic osteomyelitis.

Forty-eight episodes of osteomyelitis, 30 acute and 18 chronic, were evaluated in a prospective multicenter collaborative study to determine whether a standardized serum bactericidal test could predict outcome of infection. All centers used a microdilution test method that defined the recognized important test variables, including inoculum size, culture medium, dilution technique, incubation time, method of subculture, and bactericidal endpoint. In patients with acute osteomyelitis, peak serum bactericidal titers had no predictive value; however, trough titers of 1:2 or greater accurately predicted cure, whereas trough titers of less than 1:2 predicted therapeutic failure. In patients with chronic osteomyelitis, peak serum bactericidal titers of 1:16 or greater and trough titers of 1:4 or greater accurately predicted cure, whereas peak titers of less than 1:16 and trough titers of less than 1:2 accurately predicted failure. It is concluded that this standardized serum bactericidal test provides good prognostic information in patients with osteomyelitis, and it is recommended that patients with acute osteomyelitis have serum bactericidal titers of 1:2 or greater at all times and that patients with chronic osteomyelitis have serum bactericidal titers of 1:4 or greater at all times.

Multicenter collaborative evaluation of a standardized serum bactericidal test as a prognostic indicator in infective endocarditis.

One hundred twenty-nine patients with bacterial endocarditis were evaluated in a multicenter collaborative study to determine whether a standardized serum bactericidal test could predict the outcome of the infection. All centers used a microdilution test method that defined all known test variables, including inoculum size, culture medium, dilution technique, incubation time, method of subculture, and bactericidal endpoint. Peak serum bactericidal titers of 1:64 or more and trough serum bactericidal titers of 1:32 or more predicted bacteriologic cure in all patients. The traditionally recommended serum bactericidal titer of 1:8 had statistically significant predictive accuracy at trough antibiotic levels only. The serum bactericidal test was a poor predictor of bacteriologic failure and ultimate clinical outcome, which depends on many factors. Wider recognition by physicians and clinical microbiologists that this in vitro test of antimicrobial activity can accurately predict bacteriologic success but cannot accurately predict either bacteriologic failure or clinical outcome could lead to a better consensus about its appropriate use. On the basis of the results of this study, peak serum bactericidal titers of 1:64 or more and trough serum bactericidal titers of 1:32 or more are recommended to provide optimal medical therapy for infective endocarditis.

Candidal suppurative peripheral thrombophlebitis.

Transient candidemia is common with prolonged intravenous therapy. Sustained candidemia, however, usually indicates a persistent focus of infection. A complication of intravenous therapy not previously emphasized is persistent candidemia caused by candidal suppurative peripheral thrombophlebitis. We report six cases that appeared during intravenous therapy: the infection was characterized by a thrombosed peripheral vein at an intravenous site with manifestations for candida septicemia with or without disseminated candidiasis. In two patients, the source of the process was occult; the examination showed only a thrombosed noninflamed vein. In all cases, surgical exploration showed the thrombosed veins to be suppurative with positive cultures for Candida. Special stains, moreover, showed Candida in the luminal clot and the vascular wall. In the five surviving patients, cure was achieved by excision of the affected vein. Four received a short course of amphotericin B and 5-fluorocytosine, and one patient received amphotericin B only.

Hemophilus influenzae pneumonia in adults: report of five cases caused by ampicillin-resistant strains.

Recently there has been increased recognition of Hemophilus influenzae as a cause of pneumonia in adults. Although ampicillin-resistant strains of Hemophilus influenzae have been a major problem in pediatric practice, such strains have not previously been noted to be a significant problem in the treatment of adult pneumonia. We report 5 cases of pneumonia caused by beta-lactamase-producing strains of Hemophilus influenzae. These organisms were susceptible to chloramphenicol but resistant to ampicillin. Cure was achieved by treatment with chloramphenicol after the initial treatment with ampicillin had failed. The ability of a microbiology laboratory to isolate and to test routinely for ampicillin-resistant strains is an important factor in the successful treatment of Hemophilus influenzae infections.

Model for disseminated intravascular coagulation: bacterial sepsis in rhesus monkeys.

DIC is a hemorrhagic syndrome frequently encountered as a complication in severe gram-negative bacterial sepsis. An animal model for sepsis-associated DIC was developed in order to permit study of the appearance and development of this syndrome in relation to the entire disease process. Rhesus monkeys (4 to 6 kg) were infected by intravenous injection of 10(9) Salmonella typhimurium organisms and studied for a period of 7 to 10 days following infection. Ten of 23 infected monkeys developed petechial rash characteristic of DIC, which appeared on days 1 to 2 infection and lasted 4 to 5 days. In the group of monkeys developing rash, activation of coagulation was suggested by an 80% decrease in platelet count and 20% to 30% increases in PT and APTT. Fibrinolytic system activation was indicated by the appearance of FDP. Kinin system activation was evidenced by decreases in both prekallikrein nad kininogen. Changes in laboratory tests suggestive of subclinical DIC were also noted in infected monkeys which did not develop a rash. Pathologic evidence of DIC was obtained through observation of numerous fibrin thrombi in the kidneys of the only monkey which died in the course of infection. Occurrence of DIC in association with this experimental infection in rhesus monkeys was established on the basis of clinical, laboratory, and pathologic criteria. Expression of the syndrome on days 1 to 2 following infection correlated with the period of increasing bacteremia.

Disseminated intravascular coagulopathy during experimental pneumococcal sepsis: studies in normal and asplenic rhesus monkeys.

Disseminated intravascular coagulation (DIC) was induced in both normal and asplenic rhesus monkeys by intravenous challenge with Streptococcus pneumoniae. Our observations in the infected monkeys have led us to conclude that (1) pneumococcal capsular polysaccharide (PCP), immune complexes and complement may not have primary roles in the initiation of DIC; (2) intact pneumococci may be catalysts for the development of DIC; (3) the initial event in DIC may be activation of Hageman factor; and (4) evidence of activation of Hageman factor-dependent systems is present regardless of severity of infection.