A comparison of virulence patterns and in vivo fitness between hospital- and community-acquired methicillin-resistant Staphylococcus aureus related to the USA400 clone.

Methicillin-resistant Staphylococcus aureus (MRSA) isolates genetically related to the CA-MRSA clone MW2/USA400 (ST1-SCCmecIV lineage) from the United States have emerged in hospitals in Rio de Janeiro and are associated with nosocomial bloodstream infections. To understand the virulence mechanisms involved in the adaptability of ST1 isolates as a hospital pathogen in Rio de Janeiro, we compared the virulence traits and fitness properties of the Brazilian isolates with those displayed by the CA-MRSA isolates from the United States. Similar to the USA400 from the United States, all the Brazilian isolates tested carried the genes encoding SEH and LukDE. In contrast, none of the Brazilian isolates carried the lukSF PVL, sea, sec, and sek genes. Competition experiments in mice demonstrated a significant increase in the fitness for the CA-MRSA isolates MW2 and USA400-0051 from the United States compared to other isolates. In the foreign body animal model, 83 % more North-American bacterial cells were recovered compared to the Brazilian ST1 isolates. Differences in gene expression of important virulence factors were detected. Transcription of rnaIII and psmα3 was increased about two-fold in the isolates from the United States, and sasG about two-fold in the Brazilian isolates. Thus, it is possible that the virulence attenuation observed among the Brazilian hospital isolates, associated with the acquisition of multiple resistant determinants, are consequences of microevolutionary events that contributed to the necessary fitness adjustment of this lineage, allowing a typically community-acquired MRSA (MW2/USA400) to emerge as a successful hospital pathogen (Brazilian ST1-SCCmecIV).

Restriction modification (RM) tests associated to additional molecular markers for screening prevalent MRSA clones in Brazil.

In this study, we associated the restriction modification (RM) tests to the polymerase chain reaction (PCR) detection of molecular markers (SCCmec III, seh, agr II-SCCmec IV, and lukSF) for revealing the main methicillin-resistant Staphylococcus aureus (MRSA) clones circulating in Brazil. This simple and rapid approach allowed a precise classification of the MRSA analyzed when compared with pulsed-field gel electrophoresis (PFGE) data.

In vivo cellular tropism of human T cell leukemia virus type II (HTLV-II).

To investigate the in vivo cellular tropism of human T cell leukemia virus type II (HTLV-II), subpopulations of fresh peripheral blood mononuclear cells from infected individuals were isolated and analyzed by polymerase chain reaction for the presence of provirus. In eight of nine patients, HTLV-II was detected exclusively in the CD8+ T lymphocyte population. In the remaining patient, provirus was also detected in CD4+ T lymphocytes. Provirus was not detected in B lymphocytes or monocytes of any patient. These results suggest that in vivo HTLV-II has a preferential, and perhaps in some cases, an exclusive tropism for CD8+ T lymphocytes. The findings contrast sharply with those on HTLV-I where there is a preferential tropism for CD4+ T lymphocytes. Although HTLV-II infection has not been consistently associated with any lymphoproliferative disorders, the results suggest that if these occur, they may be different from those known to be associated with HTLV-I.

Serious Pseudomonas aeruginosa infection in AIDS.

During a 7-year period, 32 patients with Pseudomonas aeruginosa infection were identified on an HIV treatment service at a university-affiliated teaching hospital. The number of cases increased from 2 in 1986 to 13 in 1992. Affected patients had evidence of advanced HIV infection. In those treated with antiretroviral therapy, 96% of infections occurred > 1 year after initial presentation with HIV disease. Eighteen cases of pneumonia and 14 nonpulmonary (central venous access device, soft tissue, middle ear-mastoid, corneal, and peritoneal) infections were seen. Comparison with matched controls identified use of a central venous access device and administration of aerosolized pentamidine, corticosteroids, or ganciclovir as risk factors for infection (odds ratios, 5.3, 6.5, 15.0, and 9.0, respectively; p = 0.004, 0.007, 0.02, and 0.02, respectively). Seventy-five percent of cases had community onset, but time since last hospital discharge was significantly shorter in study patients than in controls (mean difference, -85 days; 95% confidence interval, -24 to -146; p = 0.01). Among evaluable cases, outcome was fatal (survival < or = 30 days) in 2 of 16 (13%) patients in whom initial antibiotic therapy was appropriate and 8 of 14 (57%) patients in whom initial therapy was not appropriate (p = 0.016). Ten recurrent infections were seen in 8 of 21 patients who survived the initial infection. Median survival after onset of infection was only 80 days. Pseudomonas aeruginosa infection is an increasingly frequent, severe complication of advanced HIV disease. Several treatment and prevention strategies used in the management of advanced HIV disease are associated with an increased risk of infection.

Rhabdomyolysis and hypoxia associated with prolonged propofol infusion in children.

Propofol, a new anesthetic, is now used more commonly to sedate patients in the intensive care unit. Propofol's rapid elimination has popularized its use to induce and maintain hypnosis in patients with refractory status epilepticus. It is also associated with occasional severe metabolic acidosis and hypoxia of indeterminate cause in children. We report a child and an adolescent who developed severe metabolic acidosis, progressive hypoxia, and rhabdomyolysis during maintenance infusion of propofol for the treatment of refractory status epilepticus. We suggest that propofol should not be used for prolonged sedation in children until its safety can be ensured.

Service delivery for patients with HIV in a rural state: the Vermont model.

The incidence of human immunodeficiency virus (HIV) infection is increasing rapidly in rural areas of the United States. Barriers to health-care delivery for this patient population include the complexity of this rapidly changing field, inexperienced rural physicians, long travel distances to receive expert care, lack of psychosocial support systems, and concerns about confidentiality. Models of HIV care for rural areas have not been developed that remove these barriers. We present the philosophy, structure, implementation, and services of a model of care in Vermont that is designed to remove many of these barriers and bring HIV expertise into the rural areas of the state. Three HIV specialty clinics have been developed in regional hospitals throughout the state. The clinic team includes an HIV-trained nurse practitioner and social worker from the hospital, a client consultant from the regional AIDS service organization, and an infectious disease specialist who travels to each of the clinics monthly. Patient care will be centralized in these regionally located clinics. The dispersion of HIV care among numerous and inexperienced rural providers will be obviated. Confidentiality will be emphasized within the hospital environment. The model has the potential to provide a complete continuum of medical care and psychosocial case management, integrate patient care and regional provider education, and increase community awareness. Patients will be able to receive their care in their own community, avoiding long travel distances. This may encourage patients to seek care earlier in their illness. The model may be adaptable to other rural areas of the United States.

Parental attitudes toward BB and pellet guns.

As well as describing our pediatric BB and pellet gun injuries and the circumstances surrounding these injuries, we also evaluated parental perceptions of the dangers of BB and pellet guns. A convenience sample of three groups of parents and their children presenting to a Midwest, urban, children's hospital emergency department was prospectively enrolled. The three groups of parents included the injured group, which consisted of the parents whose children had been injured by BB or pellet guns; the gun group, which consisted of the parents who allowed their children to possess BB or pellet guns but had not sustained injury from these guns; and the no gun group, which consisted of the parents who did not allow their children to have these guns. All parents completed a survey concerning their attitudes toward BB and pellet guns. Twenty-eight parents completed questionnaires in each of the three groups. Most BB and pellet gun injuries occurred in adolescent males at home without adult supervision and were inflicted by a friend or by themselves. The injured group and the no gun group viewed BB and pellet guns as significantly more dangerous than the gun group. Parents who allow their children to have BB or pellet guns appear to misperceive their potential for injury by allowing their children to use these guns in an unsafe manner. Clinicians must educate parents about the significant potential for injury of nonpowdered guns.

Acne management. Primary care physician or dermatologist?

The question of who should treat acne patients--primary care physicians or dermatologists--is debatable. To determine physicians' attitudes toward, and referral patterns in, acne management, the authors conducted two studies. According to results of the first study, primary care physicians were less likely than dermatologists to feel referral was necessary for acne management. Primary care physicians felt that they should treat most patients with less severe (comedonal and papulopustular) acne and were neutral about referral of patients with nodulocystic acne. Dermatologists were neutral about referral of patients with less severe acne and recommended referral for most patients with nodulocystic acne. Results of the second study showed that almost all patients with less severe acne and most patients with nodulocystic acne were managed by primary care physicians. The authors feel that primary care physicians can and should handle most cases of acne without referral.

Clinical predictors of computed tomographic abnormalities following pediatric traumatic brain injury.

Children commonly seek attention in emergency departments following head injury. Head computed tomography (CT) is often used to decide subsequent disposition. Clinical criteria predicting CT abnormalities would allow effective and timely treatment and minimize unnecessary procedures depleting overburdened medical resources. We prospectively compared presenting clinical features with subsequent emergent head CT in 300 children less than 19 years old over a nine-month period. The disposition of patients following imaging was also recorded. Only suspected abuse was more than 50% positively predictive in children below age two and those above age two. Two signs were more than 67% positively predictive in both age groups: focal motor deficit and pupillary asymmetry. Patients with abnormal CTs were the only children to undergo emergent neurosurgery (30%) and were nearly five times as likely to be intensively monitored. Children with normal CTs were nearly five times as likely to be observed in a routine department or at home. We conclude that no single clinical feature can predict with certainty an abnormality on immediate head CT. However, children suspected of being abused, and those with focal motor deficits or pupillary asymmetry, should be imaged. Finally, emergent CT when judiciously ordered likely reduces unforeseen morbidity and minimizes costly intensive care observation.

Artificial neural network predicts CT scan abnormalities in pediatric patients with closed head injury.

BACKGROUND: Artificial neural networks (ANNs) use nonlinear statistical modeling techniques to explore relationships in complex clinical situations. This study compared predictive ability of a trained ANN model to that of physician prediction of cranial computed tomographic (CT) scan abnormalities in children with head injury. METHODS: A prospective cohort of 351 patients who presented with head trauma and underwent CT scans were studied. All pertinent data on historical and demographic information, and clinical features were recorded. Emergency department physicians used clinical judgment to record pretest probability of abnormal CT scans for all patients prospectively. Similar data from a retrospective chart review of 382 patients with head injury in the immediate preceding year were collected and used to train the ANN. Data from the prospective study was used to validate the ANN, construct a logistic regression model, and compare physician prediction. RESULTS: Forty-five (12.9%) of 351 patients had abnormal CT scans. In predicting CT scan abnormality, the ANN model was more sensitive (82.2%) compared with physician prediction (62.2%). CONCLUSION: ANNs may serve as a useful aid for decision support for emergency physicians in predicting intracranial abnormalities in closed head injury.

Adjuvant specific immunotherapy of resectable squamous cell lung carcinoma. Analysis at the eighth year.

From June 1976 to June 1981, 86 patients with resectable (Stage I and II) squamous cell lung carcinoma were entered into a randomized controlled study with three arms: Control Group - no treatment postoperatively. Specific Immunotherapy Group - three monthly doses of 500 micrograms of tumor associated antigen (TAA) emulsified with complete Freund's adjuvant (CFA). Nonspecific Immunotherapy Group - three monthly doses of CFA emulsified in saline. All the patients in the study received skin tests with PPD (5TU) and 100 micrograms of the same TAA used for the immunotherapy at 1, 4, 6, 9, and 12 months postoperatively. Patients in both immunotherapy groups showed a tendency for a better disease-free interval and overall survival compared to those of the control, but these interval and beneficial therapeutic effects were statistically significant only in the Group III patients who had no hilar lymph node metastasis (T1N0 and T2N0). Although Group III was originally designated as a nonspecific immunotherapy group, retrospectively, it should be called a lowdose specific immunotherapy group because these patients actually received a total of 500 micrograms of TAA (as skin tests) and three doses of CFA at separate sites.

Adjuvant, specific, active immunotherapy for resectable squamous cell lung carcinoma: a 5-year survival analysis.

In 1976 Stewart et al. (Annals of the New York Academy of Sciences 277:436-466) reported the effectiveness of adjuvant specific active immunotherapy of lung carcinoma in improving the postoperative survival of stage I lung carcinoma patients in a phase II study using lung carcinoma-associated antigen (TAA) and complete Freund's adjuvant (CFA). A phase III study was then designed by the authors to see the effects of specific active immunotherapy compared to the conventional management (no treatment) and to nonspecific immunotherapy. From 1976 to 1981, 85 patients with resectable (stages I and II) squamous cell lung carcinoma were entered into a randomized study: 1) control group; 2) specific immunotherapy group--three monthly doses of 500 micrograms of TAA emulsified with CFA; 3) nonspecific immunotherapy group--three monthly doses of CFA emulsified in saline. All the patients in the study received skin tests with 100 micrograms of the same TAA used for the immunotherapy. Recently, a 5-year follow-up of all the patients became available: The life table 5-year survival of group 1 was 34%, of group 2 was 75%, and of group 3 was 53%. The median survivals for the three groups were group 1, 38 months; group 2, 106 months; and group 3, 71 months. The difference was significant at P = .007 (Cox-Mantel test).