To a new student in this field, with a background in the economics of health care financing and insurance, there appear to be many challenging issues regarding: a) the efficacy of particular infection control measures; b) the calculation of economic benefit from particular measures; c) the determinants of the actual levels of expenditure on infection control and the measures actually adopted; and d) the rationale and pitfalls of regulatory standards such as those recommended by the Centers for Disease Control or adopted by the Joint Commission on Accreditation of Hospitals.

Review of necropsy reports for evidence of undiagnosed antemortem infection is included by the Joint Commission on Accreditation of Hospitals as an element of an effective hospital infection control program. We reviewed records of 155 patients autopsied at St. Paul-Ramsey Medical Center between January 1, 1980 and March 31, 1981. In 13 patients (8%), there was a discrepancy between documentation of infection during the patient's hospitalization and at autopsy. However, in none of these cases was this information useful in our infection control program. We doubt the effectiveness of necropsy review as a tool for nosocomial infection control.

Although by 1931 I. Ph. Semmelweis' achievements and the tragedy of his life had been given their due place in the history of mankind, Alexander Fränkel, formerly Theodor Billroth's assistant and later his biographer, critically stated that the discoverer of the causes of puerperal fever should have defended his discovery with facts rather than with fanaticism. It was only a few years after Semmelweis' death, for instance, that Billroth made laborious experiments. Billroth's work on Coccobacteria had important implications and even influenced Robert Koch, although his hypotheses did not really predict the pathogenic and specific nature of microbes. In 1847 Semmelweis postulated his theory; ie, that the pathological-anatomical changes which he observed in the bodies of the women who died in childbed, in their newborn infants, and in the autopsy findings on his friend Jakob Kolletschka were an entity, morphologically and clinically. He summed them up under the concept of pyemia. Even though Semmelweis was continually abhorred by the evident statistics and would have been able to prove his discovery through animal experiments, he primarily took to the pen to defend his opinion vehemently. Only the clinical facts proved him right during his lifetime; the triumph of bacteriology which began after his death made him not only the “savior of mothers” but also a genial ancestor of bacteriology.

Candida species were once largely regarded merely as causes of aggravating, but rarely life-threatening mucocutaneous infections such as thrush, vulvovaginitis, and intertrigo. Now, however, Candida species have assumed the role of major nosocomial pathogens. This change has paralleled the advent of aggressive cancer chemotherapy, the widespread use of parenteral nutrition, and the practice of advanced surgical techniques including cardiovascular procedures.

Candida is a heterogeneous genus presently grouped with the Fungi Imperfecti (Deuteromycetes). There are over 80 species of Candida; only seven, however, have been recovered from humans: Candida albicans, Candida tropicalis, Candida pseudotropicalis, Candida guilliermondi, Candida krusei, Candida parapsilosis, and Candida stellatoidea. Approximately 90% the systemic Candida infections are due to C. albicans; most of the remaining infections are due to C. tropicalis. Candida species are normal commensals of humans. They are commonly found on the skin, in the gastrointestinal tract, sputum, the female genital tract, and urine from catheterized bladders. C. albicans is found only in human beings and in animal reservoirs. In other sites, such as hospital environments, Candida probably represents contamination by human excreta. Other Candida species may be cultured from soil and other environmental locations. Unlike Aspergillus species, Candida species are uncommon laboratory contaminants.

Environmental transmission of Clostridium difficile, the causative agent of antibiotic-associated pseudomembranous colitis (PMC), has been supported by animal studies and implicated in spread of C. difficile among leukemic children receiving non-absorbable antibiotics. We report antibiotic-associated C. difficile-related colitis in two adults who shared a commode chair during hospitalization.

Serratia marcescens has an interesting and many-faceted history. The presence of the red pigmented organism on starchy food products long had been noted and was thought to be blood; its presence on consecrated wafers was thought to be the blood of Christ. It was not until 1819 that Bizio, a pharmacist, demonstrated that a microorganism was responsible for the red pigment. He named this microorganism Serratia marcescens; Serratia in honor of Serafino Serrati, an Italian physicist who invented the steamboat and marcescens from the Latin, “to decay.”

Because of the pigment production and because Serratia marcescens was believed to be a benign, saprophytic organism, it was used widely as a biological marker from 1906 to 1968. This use has been controversial in regard to experiments conducted by the US Army involving biological warfare techniques. In addition, the recognition in the 1950s of the ability of this organism to cause nosocomial infections has curtailed its use as a biological marker. Serratia marcescens is now recognized as a cause of serious infections in man. It has been implicated in practically every kind of infection and is a particularly serious problem with nosocomial infections.

Surveillance activities for the detection of nosocomial infections at the University of Virginia Hospital (Charlottesville, Virginia) and at hospitals participating in the Virginia Statewide Infection Control Program have focused on outbreaks and device-related infections which are potentially preventable. Eleven outbreaks of nosocomial infections were identified at the University of Virginia Hospital between January 1, 1978 and December 31, 1982 (9.8 outbreaks/100,000 admissions). Ten of the 11 were centered in critical care units. The 269 patients involved in the epidemics represented 0.2% of all hospital admissions and 3.7% of all patients who developed nosocomial infections. Eight of the 11 outbreaks involved infection of the bloodstream, and the 90 patients who developed a bloodstream infection as part of an epidemic represented 8% of all patients with nosocomial bloodstream infections identified during the five-year study period. The reservoir of the 11 outbreaks involved devices (5), contaminated cocaine (1), probable blood products (1), other patients (3), and nursing personnel (1). Forty-one percent of all nosocomial bloodstream infections and 41% of all nosocomial pneumonias occurred in intensive care units (ICUs).

In 38 hospitals in the state of Virginia with ICUs and practitioners who voluntarily reported surveillance data between June 1,1980 and May 31,1982, there were 264,757 patients admitted and a crude infection rate of 3%. Of note is that 1,867 of the 7,407 nosocomial infections (25%) occurred in the ICU patients. Several factors point to a compelling argument that the highest priority in infection control resources be assigned to the prevention and control of ICU infections: ICU patients often have serious device-related infections and may be identified as high risk prior to infection. Furthermore, they are at risk of being infected as part of a major outbreak. Such characteristics define a population of hospitalized patients, many of whose infections are preventable.

Nosocomial respiratory tract infections are major causes of excessive morbidity and mortality in US hospitals, affecting an estimated five to ten of every 1,000 patients. Patients with serious underlying diseases have an especially high risk of acquiring these infections, and that risk is magnified by exposure to respiratory therapy. Until recently, contaminated respiratory care devices were a major cause of infection, but procedures for the management of these devices have decreased their role substantially. Now, aspiration of oropharyngeal flora appears to be responsible for most cases of bacterial respiratory infections. Therefore, techniques to alter the flora of the oropharynx and to diminish the risk of aspiration are important priorities for infection control. Exposure to intensive care units (ICUs) is also a major risk factor for nosocomial pulmonary infection, and person-to-person spread of microorganisms within ICUs seems to be responsible for some of these infections.

Increasing numbers of pulmonary infections are being caused by newly identified or previously uncommon pathogens, and this shift requires that traditional control techniques be reevaluated to assure that they remain relevant.

Few new techniques have been developed recently to alter host susceptibility, prevent acquisition of virulent pathogens, or eradicate infectious organisms from their sources, but effective infection control programs in hospitals appear to reduce the incidence of nosocomial pulmonary infection, and implementation of these programs deserves serious consideration in all hospitals.