Robert W. Haley

The emergence of methicillin-resistant Staphylococcus aureus infections in United States hospitals. Possible role of the house staff-patient transfer circuit.

Infections with methicillin-resistant strains of Staphylococcus aureus appear to be occurring with increasing frequency in some U.S. hospitals about a decade after a similar increase in Britain and other countries. In the United States, clustered methicillin-resistant S. aureus infections reported in scientific journals and in three hospital surveys have been almost entirely in large, tertiary referral hospitals affiliated with medical schools. Among 63 hospitals regularly reporting infections from 1974 to 1981 in the National Nosocomial Infections Study, the increase in methicillin-resistant S. aureus infections was entirely due to substantial increases in only four hospitals, all of which were large, tertiary referral centers affiliated with medical schools. The predominance of methicillin-resistant S. aureus infections in these large hospitals may be due to the large numbers of patients at high risk of infection and to the interhospital spread of the organism by the transfer of infected patients and house staff from similar hospitals or from nursing homes.Abstract Infections with methicillin-resistant strains ofStaphylococcus aureusappear to be occurring with increasing frequency in some U.S. hospitals about a decade after a similar increase in Brit...

Measuring the costs of nosocomial infections: Methods for estimating economic burden on the hospital

To compete more effectively for resources, it is increasingly important for infection control practitioners to estimate the costs of nosocomial infections and the amount of money their infection control programs save the hospital. Studies on costs should estimate both extra length of stay and extra costs attributable to infectious complications. Cost estimates should either adjust charges by a cost to charge ratio, which is relatively easy, or estimate hospital costs directly by detailed cost-accounting, which is comparatively more difficult. If there is insufficient time to measure costs concurrently in every infected patient, comparative studies can be done by comparing infected and uninfected patients matched on characteristics that control for the preexisting differences between them. Diagnosis-related groups and the number of diagnoses appear to be useful matching variables because they are strongly associated with both nosocomial infection and length of stay. The final results should be expressed as either potential or actual savings to the hospital, depending on whether significant reductions in nosocomial infection rates have been achieved.

Tuberculosis epidemic among hospital personnel.

Six employees of the emergency department at Parkland Memorial Hospital developed active tuberculosis in 1983-1984. Five of the cases occurred four to 12 months after exposure to the index case, a patient with severe cavitary tuberculosis seen in the emergency department in April 1983. One resident physician developed cavitary disease after exposure to this patient. An additional employee case may have resulted from transmission from one of the initial employee cases. One immunocompromised patient may have acquired tuberculosis as a result of exposure to the index case. In addition, the tuberculin skin tests of at least 47 employees exposed to the index case converted from negative to positive. Of 112 previously tuberculin-negative emergency department employees who were tested in October 1983, 16 developed positive skin tests, including the 5 employees with active disease. Fifteen of these new positives had worked on April 7, 1983, while the index case was in the emergency department (X2 = 20.6, P less than 0.001). Factors related to the genesis of the epidemic included the disease characteristics in the index case and the recirculation of air in the emergency department. This investigation indicates that city-county hospital emergency department employees should be screened at least twice a year for evidence of tuberculosis and that the employee health services of such hospitals should regard the surveillance of tuberculosis infection among personnel at a high-priority level.

Update from the SENIC project: Hospital infection control: Recent progress and opportunities under prospective payment

From a survey of all U.S. hospitals in 1976 and of a random sample in 1983, we found that the intensity of infection surveillance and control activities greatly increased, and the percentage of hospitals with an infection control nurse per 250 beds increased from 22% to 57%. The percentage with a physician trained in infection control remained low (15%), and there was a drop in the percentages of hospitals doing surgical wound infection surveillance (from 90% down to 79%) and reporting surgeon-specific rates to surgeons (from 19% down to 13%). There was an increase in the percentage of hospitals with programs shown to be effective in preventing urinary tract infections, bacteremias, and pneumonias, but not surgical wound infections. The percentage of nosocomial infections being prevented nationwide appears to have increased from 6% to only 9%, whereas 32% could be prevented if all hospitals adopted the most effective programs.

Pseudobacteremia Attributed to Contamination of Povidone-Iodine with Pseudomonas cepacia

Pseudomonas cepacia was recovered from the blood cultures of 52 patients in four hospitals in New York over 6 months from April through October 1980. Epidemiologic investigation in one hospital indicated that the positive results of blood culture represented pseudobacteremias and implicated a 10% povidone-iodine solution used as an antiseptic and disinfectant (Pharmadine; Sherwood Pharmaceutical Company, Mahwah, New Jersey) as the source of contamination. Physicians who drew blood cultures positive for P. cepacia were more likely to have left povidone-iodine on the skin before venipuncture (p = 0.026) and were more likely to have applied povidone-iodine to the blood culture bottle tops and to have left it there while inoculating the blood culture media (p = 0.007) than those who drew cultures negative for P. cepacia. Direct inoculation of Pharmadine into brain-heart infusion broth yielded P. cepacia; however, 2 weeks after the first cultures, the same Pharmadine bottles were culture negative. The iodine concentrations of the contaminated Pharmadine solutions were similar to those of 10% povidone-iodine solutions distributed by other manufacturers.

The scientific basis for using surveillance and risk factor data to reduce nosocomial infection rates

Research over the past 20 years has demonstrated that an active programme of surveillance with feedback of surgical wound infection rates to surgeons can reduce subsequent rates by 30-40%. For surveillance data and feedback to be meaningful and influential, however, certain rigorous methodological principles must be observed. First, surveillance data must be collected in an accurate, efficient and confidential manner. This requires written definitions of infection, regular clinical case-finding, post-discharge follow up for short-staying patients, and computer storage, analysis and reporting of the data in coded form that does not publicly identify individuals. Second, the variation in intrinsic risk of the patients of the various surgeons must be controlled for by stratifying the final infection rates on a multivariate risk index, which combines the traditional classes of wound contamination with measures of intrinsic patient susceptibility. This can be accomplished with a relatively small commitment of time by the Infection Control Nurse with the aid of sophisticated computer software that is now available.

Nosocomial surgical infections: incidence and cost

The data reported in this article support the findings of Dr. Altemeier; that is, infections among surgical patients remain a serious problem today. Urinary tract infections account for approximately 40 per cent of nosocomial infections among surgical patients. Surgical wound and skin infections account for one third of the nosocomial infections among surgical patients. Rates for wound infections rise with age, with increased length of hospitalization before surgery, and with increased duration of surgery. They are higher for patients who have an infection at a distant site and for those who have the more hazardous surgical procedures as determined by risk categories. Gram-negative organisms are more prevalent than gram-positive organisms. A nosocomial surgical wound infection lengthens the hospitalization by an average of 7.4 days and raises the cost of hospitalization by more than 800 dollars. Further analysis of the data is necessary in order to identify the risk factors likely to be most helpful in determining which patients are at increased risk of acquiring a nosocomial infection. Only when these factors are identified can the most direct and effective contact and preventive measures be implemented.

High cost nosocomial infections.

The average charge per patient due to nosocomial infection for 215 nosocomial infections in 183 study patients was

Nosocomial Bacteriuria: A Prospective Study of Case Clustering and Antimicrobial Resistance

693. These cost, however, were concentrated in very few patients; 5% of patients accounted for nearly one-third of total charges. The 10% of patients with highest nosocomial infection cost were patients on Medical or Surgical services; these services were utilized in 71% of patients with nosocomial infection and accounted for 86% of the attributable charges. Among the 22 most costly infections, 17 occurred in surgical wounds and lower respiratory tract. Although these sites accounted for 46% of the infections, they resulted in 77% of the total nosocomial infection charges. Patients with a primary diagnosis of injury had particularly costly infections. Combined analysis of these variables revealed two groups for whom nosocomial infections were especially costly: surgical patients who acquired wound infections after injuries, and medical patients with lower respiratory infections.

Nosocomial infections in surgical patients: Developing valid measures of intrinsic patient risk

To investigate the role of cross-infection in nonepidemic nosocomial bacteriuria in a large, university-affiliated hospital, we identified in adult patients admitted over an 11-week period all cases caused by organisms of the same genus, species, and antimicrobial susceptibility and clustered by date of onset and hospital ward. Further laboratory studies were conducted to verify clustering. Among the 3452 patients studied, 194 cases of nosocomial bacteriuria were identified; 49 appeared clustered by epidemiologic evidence. Additional laboratory tests verified clustering in 30 cases (15.5%). We found that 90% of clustered and 76% of nonclustered cases had had previous urinary catheterization; Pseudomonas aeruginosa, Serratia marcescens, and Citrobacter freundii often caused clustered infection while Escherichia coli predominated in nonclustered cases; and resistance to gentamicin, sulfathiazole, and carbenicillin was significantly greater for pathogens from clustered cases than for nonclustered ones. This increased resistance emphasizes the need to prevent cross-infection, even in the absence of epidemics.