MUPIROCIN PREVENTS NASAL CARRIAGE OF STAPHYLOCOCCUS AUREUS

Twenty-five percent of nosocomial infections are caused by Staphylococcus aureus, which most commonly colonizes the nasal passages. A randomized double-blind trial by Perl et al has found that although intranasal mupirocin application did not lower the overall rate of S aureus surgical-site infections, it significantly reduced the rate of nosocomial S aureus infections among nasal carriers.

The study included 3,864 patients undergoing elective surgery. Patients were randomly assigned to receive either intranasal mupirocin ointment (1,933) or a placebo ointment (1,931) twice daily for up to five days before surgery.

Nasal carriage of S aureus was eliminated from 83.4% of patients in the mupirocin group, compared with 27.4% of patients in the placebo group. Among patients with nasal carriage of S aureus, the risk of a postoperative nosocomial infection with S aureus at any site was significantly lower in the mupirocin group than in the placebo group. In noncarriers, however, mupirocin had no impact on the risk of nosocomial S aureus infection at any site.

Furthermore, there was no significant difference between the mupirocin and placebo groups in the rate of surgical-site S aureus infections. As an explanation, the authors pointed out the low rates of S aureus infections overall and in patients with nasal carriage of the organism, and that some patients may have been infected with strains transmitted from health care workers or other patients.

In an accompanying editorial, Farr noted that while mupirocin prophylaxis is cost-effective in some settings, the potential exists for rapid increases in levels of resistance.

Perl TM, Cullen JJ, Wenzel RP, et al. Intranasal mupirocin to prevent postoperative Staphylococcus aureus infections. N Engl J Med. 2002;346:1871-1877.
Farr BM. Mupirocin to prevent S aureus infections. N Engl J Med. 2002;346:1905-1906.

EARLY DETECTION OF PSEUDOMONAS AERUGINOSA IN CYSTIC FIBROSIS

In patients with cystic fibrosis (CF), Pseudomonas aeruginosa infections are common and frequently occur at an early age. After a five-year study of children with CF, West et al found that the combination of newborn screening, serum P aeruginosa antibody titer monitoring, and chest radiography improved early diagnosis and treatment.

Samples of oropharyngeal secretions and serum were obtained every six months from 68 children with CF. Secretions were cultured for P aeruginosa; serum was tested for antibodies to the P aeruginosa antigens cell lysate, exotoxin A, and elastase. Chest films were taken every six months until the children were age 3 years, and yearly thereafter.

Titers to cell lysate and exotoxin A were detected a mean of 11.9 and 5.6 months earlier, respectively, than P aeruginosa was isolated in cultures from oropharyngeal secretions. Chest films showed lung abnormalities 5.8 months earlier than P aeruginosa was isolated. A rise in antibody titers correlated positively with first report of cough and with lung abnormalities on chest films.

In young children with CF, early detection of P aeruginosa is essential to prevent irreversible lung damage. The investigators recommended that longitudinal P aeruginosa serology with monitoring of exotoxin A titers become a routine part of follow-up.

West SEH, Zeng L, Lee BL, et al. Respiratory infections with Pseudomonas aeruginosa in children with cystic fibrosis: early detection by serology and assessment of risk factors. JAMA. 2002;287:2958-2967.

ASTHMA SYMPTOMS REVERSIBLE IN ELITE SWIMMERS WHO STOP TRAINING

Mild asthma has been observed in many endurance athletes, but its long-term significance has been uncertain. A five-year, prospective study by Helenius et al found that among competitive swimmers, asthma symptoms decreased after the athletes stopped training.

Forty-two elite swimmers were evaluated at baseline and after five years. Evaluation included questionnaires pertaining to respiratory symptoms and allergies, skin prick testing, resting spirometric examination, and histamine challenge testing. Twenty-six swimmers stopped training during follow-up.

Exercise-induced bronchial symptoms were reported by 27 (64%) of the swimmers at baseline. At follow-up, such symptoms were reported by 13 (81%) of the 16 athletes who were still swimming (the active swimmers) and by nine (38%) of the 26 former swimmers.

The percentage of active swimmers who had a current diagnosis of asthma increased from 31% at baseline to 44% at follow-up. In the former swimmers, this percentage decreased from 23% to 4% between baseline and follow-up.

Competitive swimmers inhale large amounts of air from immediately above the water surface and are exposed to chlorine derivatives, which may cause asthma symptoms. The authors observed that in swimmers who had stopped high-level training, bronchial hyperresponsiveness and asthma decreased or disappeared.

Helenius I, Rytilä P, Sarna S, et al. Effect of continuing or finishing high-level sports on airway inflammation, bronchial hyperresponsiveness, and asthma: a 5-year, prospective, follow-up study of 42 highly trained swimmers. J Allergy Clin Immunol. 2002;109:962-968.

POOR PATIENT OUTCOMES WITH EARLY HOSPITAL DISCHARGE

The widespread growth of managed care has resulted in shortened hospital stays and, some claim, the premature discharge of patients. In a prospective, multicenter, observational study, Halm et al developed and tested a pneumonia-specific measure of clinical stability for patients about to be released from the hospital; they found that instability on discharge is associated with significant adverse outcomes.

Investigators studied a cohort of 680 patients hospitalized with pneumonia. Clinical stability was based on body temperature, heart rate, blood pressure, respiratory rate, oxygenation, mental status, and ability to maintain oral intake. Thirty days after discharge, all patients received a standard follow-up phone call to ascertain survival, hospital readmission, and return to usual activities. One hundred thirty patients met one or more criteria for instability on discharge. In the 30 days after discharge, 80 patients died or were readmitted to the hospital, and 223 patients were unable to return to their usual activities.

In comparison to clinically stable patients, those who left the hospital with instability had higher rates of death, readmission, and failure to return to usual activities. The presence of two or more criteria for instability on discharge increased the risk of death or readmission sevenfold.

The investigators suggested that physicians use a specific, measurable definition of instability to gauge the appropriateness of hospital discharge.

Halm EA, Fine MJ, Kapoor WN, et al. Instability on hospital discharge and the risk of adverse outcomes in patients with pneumonia. Arch Intern Med. 2002;162:1278-1284.

STUDY HIGHLIGHTS NEED FOR THROMBOEMBOLISM PREVENTION

Eight risk factors account for 75% of venous thromboembolism cases, a new population-based study suggests. Institutionalization accounts for more than half of these cases.

Heit et al identified 625 residents of Olmstead County, Minnesota, who had had a first deep venous thrombosis or pulmonary embolism; each case patient was paired with an age- and sex-matched control from the community. Data were obtained by review of medical records.

Fifty-nine percent of all cases of venous thromboembolism could be attributed (in whole or in part) to institutionalization during the three months preceding the event. Hospitalization for surgery accounted for 24%; hospitalizations for other causes, for 22%; and nursing home residence, for 13%.

Malignant neoplasms not treated with chemotherapy accounted for a larger share of venous thromboembolism cases (12%) than did neoplasms treated with chemotherapy (6%). Trauma, congestive heart failure, and prior placement of a central venous catheter or pacemaker contributed to 12%, 10%, and 9% of cases, respectively. Seven percent of venous thromboembolism cases were attributable to neurologic disease; and 5%, to prior superficial venous thrombosis.

The investigators noted that nursing home residents are not usually considered for venous thromboembolism prophylaxis because they are often at risk for anticoagulant-related complications. They concluded that appropriate preventive measures should be identified and used where possible.

Heit JA, O’Fallon M, Petterson TM, et al. Relative impact of risk factors for deep vein thrombosis and pulmonary embolism. Arch Intern Med. 2002;162:1245-1248.

SURGERY NOT ALWAYS THE BEST OPTION IN RECURRENT THROAT INFECTION

Previous trials have shown that tonsillectomy reduces the number of throat infections in children meeting stringent criteria for surgery. But is the operation appropriate in children who are less severely affected? Paradise et al conducted two parallel, randomized studies of tonsillectomy/adenoidectomy in children with less severe disease than those studied in previous trials and found that the benefits of surgery do not justify its risks, morbidity, or expense.

Between 1982 and 1994, 328 children ages 3 to 15 years participated in the trials. Children were stratified both by age and by the frequency and severity of throat infections. Those without obstructing adenoids or recurrent or persistent otitis media were entered into a three-way trial in which they were randomly assigned either to tonsillectomy (58 children), to tonsillectomy with adenoidectomy (59), or to a control group (60). In a two-way trial, the children who did have such conditions were randomly assigned either to tonsillectomy with adenoidectomy (73) or to a control group (78). The primary outcome for both trials was the number of throat infections during each of three follow-up years.

In both trials, outcomes were more favorable for the surgical groups than for the control groups. However, in the control groups, the infection rates were modest and the mean rates of moderate or severe infections were low. Futhermore, about 8% of the surgical patients suffered procedure-related complications. Paradise et al concluded that the benefits of surgery did not justify the inherent risks.

Paradise JL, Bluestone CD, Colborn DK, et al. Tonsillectomy and adenotonsillectomy for recurrent throat infection in moderately affected children. Pediatrics. 2002;110:7-15.

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