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).

A double-blinded clinical trial.

A university hospital in Mexico City.

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.

Each of the study subjects received the three different PPD preparations. Risk factors for TB, including age, gender, occupation, bacille Calmette-Guerin (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.

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).

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 determine the incidence of, and risk factors for, surgical-site infections (SSIs).

Prospective observational study of all patients undergoing surgery during a 3-month period.

Two urban hospitals in Hanoi, Vietnam.

All 697 patients admitted for emergent and elective surgery.

Data were collected on all patients undergoing surgery during a 3-month period at each hospital. We stratified the data by type of surgery, wound class, and Study on the Efficacy of Nosocomial Infection Control (SENIC) risk index. The analysis was done with the data sets from each hospital separately and with the combined data. The risk factors for SSI were identified using a logistic-regression model.

During the period of observation, 10.9% of 697 patients had SSI. The SSI rate was 8.3% for clean wounds, 8.6% for clean-contaminated, 12.2% for contaminated, and 43.9% for dirty wounds. The lowest rate of SSI (2.4%) was found in obstetric-gynecologic procedures and the highest rate (33.3%) in cardiothoracic operations. Using the SENIC risk index, the incidence of SSI in low-risk patients was 5.1%; for medium-risk patients, 13.5%, and high-risk patients, 24.2%. In a logistic-regression model, abdominal surgery (odds ratio [OR], 4.46; P<.01) and wound class IV (OR, 5.67; P<.01) were significant predictors of SSI. All patients were treated with prolonged courses of perioperative antibiotics. Overall infection control practices were poor as a result of deficient facilities, limited surgical instruments, and a lack of proper supplies for wound care and personal hygiene.

There was a higher incidence of SSI in low-risk patients in Vietnam compared with developed countries. Excessive reliance on antimicrobial therapy as a means to limit SSI places patients at higher risk of adverse effects from treatment and also may contribute to worsening problems with antimicrobial resistance. Establishment of an infection control program with guidelines for antimicrobial use should improve the use of prophylactic antibiotics and attention to proper surgical and wound-care techniques. These interventions also should reduce the incidence of SSI and its associated morbidity and costs.

To study both surgical and nonsurgical nosocomial infections (NIs) seen by primary-care physicians (general practitioners [GPs]) in France.

Ongoing surveillance of postdischarge NIs by an organized group of GPs, from August 1997 to July 1999. Both the GP who personally examined the case spontaneously presenting with NI and the responsible hospital physician or surgeon were interviewed by telephone.

305 general practices from all French regions.

2,199 (29%) of 7,540 patients referred for hospitalization reconsulted the GP within 30 days of discharge. In 21 (1%) of the 2,199 cases, an NI was diagnosed by the GP and confirmed as plausible by the responsible hospital physician. We diagnosed an NI in 8 (1.3%) of the post-surgical patients and in 13 (0.8%) of the non-surgical cases within the cohort We saw eight urinary tract infections, seven surgical-site infections, three soft-tissue infections, two respiratory tract infections, and one primary bloodstream infection. In 19 patients (90%), clinical signs of NI appeared within 7 days of discharge. Assuming that all 5,431 patients who were missed for follow-up did not experience any NI, an attack rate of 0.3 per 100 admissions may be estimated for the whole group.

We diagnosed 1% of NIs following discharge from a hospital in a cohort of 2,199 patients, of which 1.3% were seen post-surgery and 0.8% following nonsurgical admissions. The percentage of postdischarge visits that were for an NI in nonsurgical patients warrants a major effort with feedback to the hospital physician to reduce infection rates.

To determine the cause of fever in critically ill children and to identify opportunities for reducing antibiotic use in this population.

Prospective case series.

A tertiary-care medical-surgical pediatric intensive care unit (PICU).

Children admitted to the PICU who experienced fever (axillary temperature >38.3°C).

Consecutive children who were febrile at any point in their PICU stay were investigated over two winter seasons. Etiology of the fever was determined by physical examination and routine microbiology and radiographic tests. Three subgroups were reviewed to approximate the number of antibiotic-days that could have been reduced; namely, those with an indeterminate source, those with a documented viral infection, and those receiving a prolonged course of antibiotics. A set of standards reflecting common antibiotic use then was applied to these three patient groups.

Of 211 subjects, the majority (83.3%) had either a definitive or suspected focus for their fever, and nearly all of these patients were judged to have an infectious etiology. The study population received a total of 2,036 antibiotic-days. Despite the high incidence of infectious causes of fever in our subjects, however, approximately 15% of total antibiotic-days could have been reduced by applying common-use standards.

Fever in the PICU was usually of defined focus and infectious in origin. However, among febrile patients in the PICU, substantial opportunity exists for reduction of antibiotic use. Trials determining the safety of antibiotic reduction in this population should be pursued vigorously.

To evaluate the contribution of screening to the detection of cases of methicillin-resistant Staphylococcus aureus (MRSA) in a chronic-care facility.

Surveillance and laboratory observational study.

During a 7-month period, we compared imported and acquired MRSA in a chronic-care center by screening patients for carriage of MRSA on admission and discharge, and by recording all cases of clinical specimens positive for MRSA

The study was conducted in a 120-bed chronic-care center. This center admits approximately 850 patients per year. Approximately 90% of the patients were elderly and were admitted from other hospitals.

Of 519 patients admitted during the study period, 129 were positive for MRSA at some point during their residence, including 60 (11.6%) with MRSA found within 48 hours of admission and 69 (13.3%; 53% of all positives) with nosocomial MRSA Of the 519 admissions, 332 (64%) were discharged, of whom 62 (19%) were positive for MRSA. Of these 62, 43 (69%) acquired their MRSA during their stay in the center.

Our study confirms the amplification effect of chronic-care facilities on MRSA propagation. It also shows that screening for MRSA carriage in a chronic-care center facilitates the early identification of a large proportion of patients with MRSA.

To determine the incidence of, and risk factors for, nosocomial infections (NIs) occurring among hematopoietic stem cell transplantation (HSCT) recipients during hospitalization and to evaluate the impact of these NIs on patient outcome.

A two-year prospective observational study in two HSCT units.

All patients admitted to the HSCT units between February 1997 and March 1999.

A teaching hospital.

After admission to the HSCT units, the patients were followed prospectively on a daily basis to collect all pertinent variables for the development of NIs.

49 NIs were identified in 34 of the 143 patients screened. The incidence of NIs and infected patients was 34.2% and 23.7%, respectively. The incidence density of NI was 8.96 per 1,000 patient-days. The most frequent NIs were bloodstream infections ([BSIs], 42.8%) and respiratory tract infections (28.6%). Other sites involved were as follows: eye (8.2%), urinary tract (6.1%), gastrointestinal tract (6.1%), skin (4.1%), ear (2%), and central venous catheter ([CVC], 2%). Because of the predominance and clinical relevance of BSIs, we examined both intrinsic and extrinsic risk factors associated with these infections. Independent risk factors for BSIs were allograft from matched unrelated or partially matched family donor, graft-versus-host disease (GVHD) prophylaxis without methotrexate (MTX), type of CVC, and duration of total parenteral nutrition. Four variables were independently associated with mortality occurring during hospitalization: culture-proven BSIs, advanced disease phase at transplant, type of transplant, and absence of MTX for GVHD prophylaxis.

The study identified several factors associated with increased risk of BSIs among HSCT patients. Because BSIs are life-threatening complications for HSCT recipients, preventive measures aimed at reducing the incidence of these infections among patients given HSCT should be adopted.