Two models of hot water washer disinfectors (Decomat 128 and Hospital A, Euroclean Canada Inc; Ontario, Canada) were evaluated by two methods for their efficacy in disinfecting anesthesia equipment. In the first method, three different microbial suspensions were each sealed into 30 capillary tubes. In the second method, corrugated anesthesia tubes were rinsed with suspensions of each of two bacterial strains. The tubes then underwent a standard cycle in the hot water washer disinfectors and were subsequently tested for growth of microorganisms. All experiments were repeated three times, and the temperature was registered in all cases. In the capillary test, growth was rarely detected (13/540 tubes) and the inactivation factor for both apparatus was > 5 log,,. In the rinse test, no growth was detected. The mean temperature for 15 disinfection cycles was 84.2 ± 0.8°C for Decomat 128 and 88.9 ± 0.5% for Hospital A. However, for Decomat 128 we observed a variation of 3°C from one disinfection cycle to another and a progressive reduction of 2.2°C over a series of five consecutive complete cycles. Both methods gave reproducible results. Under our experimental conditions, both hot water washer disinfectors proved to be efficacious for the disinfection of reusable anesthesia equipment.

The gastric and tracheal flora of 142 consecutive patients receiving stress ulcer prophylaxis were investigated, identifying identical isolates by typing. Furthermore, the growth pattern of normal respiratory bacteria and organisms causing ventilation pneumonia at different pH values and the in vitro effect of sucralfate and bismuth subsalicylate on these bacteria in simulated gastric fluid were studied. The results obtained were as follows: (1) with rising gastric pH bacterial counts in gastric aspirates, especially gram-negatives, increased significantly; (2) in 45 (31.7%) of the patients identical organisms were first isolated in gastric samples and one to two days later in tracheal secretions; (3) ventilation pneumonia was significantly more frequent in patients with high gastric pH; (4) pathogens causing ventilation pneumonia grew well in simulated gastric fluid at higher pH values, unlike normal respiratory organisms; and (5) sucralfate and bismuth subsalicylate showed antibacterial activity against frequent causative organisms of ventilation pneumonia.

To examine evidence of a causal link between handwashing and risk of infection, a review of published literature from 1879 through 1986 was conducted. In the 107 years studied, 423 articles specifically related to handwashing were found. Articles were categorized as studies to evaluate products (50.8%), review articles (29.1%), behavioral studies (10.9%), methodologie studies (2.8%), studies linking handwashing to infection and other (3.1%). There was an increase in the proportion of handwashing articles published in the 1980s with the rate (9.4/105 citations/year) being almost double that of any other period studied. Nonexperimental and experimental studies related to handwashing were reviewed and evidence for a causal association evaluated. Except for specificity, all the elements for causality, including temporality, strength, plausibility, consistency of the association, and dose response were present. It was therefore concluded that emphasis on handwashing as a primary infection control measure has not been misplaced and should continue.

The performance of a biological indicator (BI) over a range of sterilization temperatures is known as a z value and, as defined by Roberts, is “the number of degrees change in temperature to achieve a tenfold change in the D value.” A plot of the D values versus exposure temperatures will reveal the z value as the negative reciprocal of the slope of the resulting thermal resistance curve. Historically, paper strip carriers of Bacillus stearothermophilus spores have been found to possess a z value in the range of l7°-2O°F, whereas self-contained BIs tested in our laboratories have exhibited z values as high as 64°F (Figure I), which reflects their excessively high resistance at flash sterilization temperatures. In general, such matters are not of concern to the end user until such time as false positives are encountered during flash sterilization.

Methicillin-resistant Staphylococcus aureus (MKSA) infections have become a major problem in many US hospitals in the last ten years.‘,’ Attempts to solve the problem have been hampered by many factors. One of these factors is the difficulty in eradicating the organism from colonized sites and thereby removing one of the reservoirs of endemicity. Another complicating factor is the lack of consistency in the published literature regarding what constitutes eradication and, therefore, when it is appropriate to discontinue isolation of patients or work restrictions of personnel. Even the decisions regarding when and how often to culture personnel remain difficult to define.” Finally, although the Australian experience illustrated an environmental component to an MRSA outbreak, the role of the environment in MRSA infections remains unclear. The following report describes the measures utilized to eradicate low-level MRSA skin colonization in a long-term psychiatric patient and illustrates several problems of-long-term MRSA carriage in institutionalized patients.

During the period July 1983 through December 1984, aminoglycoside-resistant Acinetobacter calcoaceticus var anitratus (ACA) were isolated from 98 patients in a university hospital. Eighty-seven percent of patients (85/98) acquired aminoglycoside-resistant ACA in the intensive care unit (ICU) and 92% (90198) of all initial isolates were from sputum. ICU patients with respiratory colonization/infection with aminoglycoside-resistant ACA were compared with matched ICU controls with other gram-negative rods in sputum. Compared with controls, the duration of ICU stay prior to colonization/infection with aminoglycoside-resistant ACA was significantly longer for cases (14.7 days υ 5.9 days, P = 0.002). Although exposures to devices and procedures were not significantly different for the two groups, cases received respiratory therapy significantly longer than did controls (14.7 days υ 6.6 days, P = 0.006). Prior to isolation of aminoglycoside-resistant ACA in sputum, cases received more cephalosporins than did controls (1.9 υ 1.2, P = 0.018); aminoglycoside usage in the two groups was comparable but cases tended to have received aminoglycoside for longer durations before colonization/infection than had controls (9.0 days υ 6.1 days, P = 0.08). Following sputum isolation of ACA, 6 of 22 cases developed ACA bacteremia compared with bacteremia in 2 of 22 controls. We conclude that factors predisposing to colonization/infection with aminoglycoside-resistant ACA were extended ICU care, prolonged respiratory therapy, and prior therapy with cephalosporins and aminoglycoside. In addition, ACA may be a more common cause of secondary bacteremia than previously appreciated.

An outbreak of gastroenteritis in New York City's largest jail involved 145 cases over a two-month period. The outbreak was unusual in that two Salmonella strains (serogroups B and D) were involved. Management of the outbreak involved screening kitchen workers by culture of stool samples, and education regarding personal hygiene. Obstacles to investigation and management of the outbreak arose out of the special nature of the jail environment; these included jurisdictional problems and high turnover of the inmate population.

Some colleagues are now touting the calculation and confidential reporting of surgeon-specific wound infection rates as the most important mechanism to reduce nosocomial surgical wound infections.' Several studies purport to show either a decline of surgical wound infections after such reporting is introduced or to demonstrate large differences in rates of wound infections among surgeons in a specific hospital. The purpose of this article is to clarify the numerous problems and deficiencies in the development of this concept and to show the essential statistical implausibility of demonstrating its effectiveness.

Antibiotic combinations are often used in the therapy of infectious diseases to broaden the antibacterial spectrum and to enhance antimicrobial activity. Another potential reason for combination therapy is to reduce or prevent the emergence of resistant organisms during therapy. Antituberculous chemotherapy provides a classic example in which drug combinations have successfully prevented the emergence of drug-resistant organisms and improved clinical outcome. The purpose of this brief report is to review the success of combination therapy in preventing resistance in more common bacterial infections.

The emergence of resistance during single-drug therapy is a well-documented clinical phenomenon, especially with the broad-spectrum ß-lactams against gram-negative bacilli. As with Mycobacterium tuberculosis, the resistant organisms are generally thought to be naturally occurring mutants selected by drug exposure. Because mutation frequencies appear to vary from 10-6 to 10-8, it is not surprising that emergence of resistant organisms observed clinically occurs primarily at sites of high organism density, such as the respiratory and urinary tracts.

The availability of both plasma-derived and recombinant hepatitis B vaccines has given hospitals and other health care institutions the possibility of significantly reducing a major infectious hazard in the workplace. With the increasing use and acceptance of these vaccines, many employees who have a significant blood or body fluid exposure (percutaneous or mucous membrane) have already completed hepatitis B vaccination. Concerns have arisen over the duration of protection of vaccination, as it has been over five years since the introduction of the plasma-derived vaccine.

In 1986, I wrote of the imminent decline in professional opportunities for the infectious diseases clinician because of unique problems with clinical practice in this specialty.' Although others have disagreed with my prophecy, none were able to refute my basic contention that it soon will be almost impossible for most new physicians with specialty training in infectious diseases to become self-supporting from a purely clinical practice. If a clinician is “an expert clinical [pertaining to or founded on actual observation and treatment of patients] physician and teacher,” then many of us are no longer only clinicians in the strictest sense of the word. The bell does toll for the pure clinician in this field of medicine, and the time of the easy establishment of a clinical practice is coming to a close. Future viability depends on developing beyond the role of clinician and becoming an “infectious diseases practitioner.”

Peritoneal dialysis has been successfully used in treating patients with end stage renal disease (ESRD) for approximately 40 years. Peritoneal infections are a frequent consequence of this procedure which has diminished its acceptance by physicians and patients alike. Since the development of an improved access catheter and automated dialysate delivery devices, peritoneal analysis has been gaining widespread acceptance as an alternative to hemodialysis in the treatment of patients with ESRD. Despite the improvement in the peritoneal dialysis systems, peritonitis continues to be a major complication for adult and pediatric patients undergoing continuous ambulatory peritoneal dialysis (CAPD).:‘-’ Although most patients have from less than one to four peritonitis episodes per year, some patients have no episodes of' peritonitis or have a significantly high occurrence (greater than four episodes) of peritonitis. Several reports have indicated that two thirds of the total number of ‘peritonitis episodes is due to gram-positive bacteria. Gram-negative bacteria accounts for approximately 15% and fungal infections account for less than 5%.

Clinical epidemiologic studies often focus on the identification of risk factors associated with hospital-acquired infections and the subsequent effects of preventive measures. Two study designs commonly used are the prospective design and the retrospective design. Both of these designs and the associated data collection issues were defined and discussed in the first article of this series. This article reviews the statistical analysis for a dichotomous risk factor and the presence or absence of a given disease for unmatched data. We focus our attention primarily on the unmatched prospective study, although we present formulae for the retrospective study as well.

We reviewed the published data on the possible impact of medical injections and blood transfusions on the spread of human immunodeficiency virus (HIV) in Africa. We also compared these results to our experience in Rwanda, central Africa. The importance of medical injections in the epidemic of HIV infection seems to differ from one area to another. The excess of injections experienced by HIV seropositive subjects in Zaire could be secondary to the parenteral treatment of early HIV-related illness or to the treatment of sexually transmitted diseases, rather than being the cause of HIV infection, as suggested by Rwandese studies. In contrast, blood transfusions have been shown to represent an important source of nosocomial HIV infection in many African countries. Effective and relatively inexpensive measures to diminish the iatrogenic spread of HIV infection in developing countries are summarized.

Respiratory syncytial virus (RSV) is the most important cause of lower respiratory tract infection in outpatients, as well as the major viral cause of nosocomial illness in pediatric inpatients. Immunity to this common pathogen is short lived and reinfection can occur later in life, even into adulthood. Virtually all children have one infection before 24 months and 50% experience two or more episodes of infection. The attack rate is substantial with about half of all infants in a community becoming ill during the season's first epidemic. About 100,000 children in the US each year become ill enough to require hospitalization, the hospitalization rate being 1411,000 during epidemic periods. In certain locations, RSV accounts for about 45% of hospital admissions for respiratory disease in children under two years of age.

We examined the persistence of hepatitis B surface antibody following hepatitis B vaccination in a group of health care workers. Of the 187 vaccine recipients screened, 39 were found to be antibody negative. Life table analysis showed the proportion retaining antibody at one, two, three, and four years from the first dose of vaccine was 92%, 84%, 73%, and 55% respectively. The likelihood of retaining antibody was significantly decreased as the age of the vaccine recipient increased. These results indicate that a large proportion of vaccine recipients no longer had detectable antibody four years after receipt of the vaccine. It remains to be shown if such individuals who have lost antibody are susceptible to the development of clinical hepatitis.

Recent concerns about the clinical relevance of susceptibility testing echo those expressed previously by a number of authors.’-” These concerns are well founded and are perhaps even more important today because of the proliferation of new antibiotics and the changes in reimbursement philosophy.” Ultimately, the question becomes that raised by David Greenwood: “In vitro veritas?” The following discussion will review the role of susceptibility testing in clinical medicine with emphasis on myth versus reality. In addition, new directions for susceptibility testing that promise increased clinical relevance will be covered.

Hospitals, insurance companies, and federal and state governments are increasingly concerned about reducing patient cost expenditures while maintaining high quality patient care. One method of reducing expenditures has been to tie hospital reimbursement with a prospective payment system based on diagnosis-related groups (DRGs). However, reimbursement under the DRG system is not acceptable for all patients in all hospitals because it is neither an accurate predictor of costs nor of clinical outcome. This deficiency poses significant problems for hospitals because DRGs are used nationwide as the prospective payment system for inpatients covered by Medicare. Several case-mix adjusters have been proposed to modify DRGs to improve their accuracy in predicting costs and outcome. We reviewed five of the most widely available indices: Acute Physiologic and Chronic Health Evaluation (APACHE II), Coded Disease Staging, Computerized Severity Index (CSI), Medical Illness Severity Group System (MEDISGROUPS), and Patient Management Categories (PMC). Recommendations for the use of a single case-mix adjuster cannot be made at this time because all indices have not been compared in sufficiently diverse settings and because some are better predictors of costs while others are better predictors of clinical outcome. Hospital epidemiologists and other infection control practitioners should be informed about these indices and their potential applications as they expand their role beyond infection control problems to issues concerning cost containment, quality assurance, and reimbursement.