Nosocomial (hospital-associated) infection continues to represent a major problem for hospitals. Gram-negative aerobic bacilli continue to be identified most frequently as etiologic agents, but a number of new pathogens now are recognized to play a role. The persons responsible for infection control efforts and in charge of the clinical microbiology laboratory (frequently the same person) must cooperate closely to attack this problem. The role of the laboratory in attempts to minimize occurrence of nosocomial infection involves six aspects: 1) accurate identification of responsible organisms, 2) timely reporting of laboratory data, 3) provision of additional studies, when necessary, to establish similarity or difference of organisms, 4) provision, on occasion, of microbiologic studies of the hospital environment, 5) training of infection control personnel, and 6) participation in activities of the hospital infection control committee.

Oral mercury-in-glass thermometers are contaminated with each use and must be decontaminated prior to reuse. It has been shown that the application of a thermometer sheath prevents contamination of the rectal thermometer. The purpose of the present study is to evaluate sheathed thermometers for contamination after oral use on dentulous patients. One hundred sterile sheathed thermometers were distributed into four groups and subjected to in vitro and in vivo conditions.

After clinical use 80% of the sheathed thermometers became contaminated, while not one of those exposed to microorganisms in vitro was contaminated. The cause for contamination was shown to be perforation of the sheath by the dentition. Thus the thermometer sheath is ineffective in preventing contamination of the mercury-in-glass thermometer when used for obtaining oral temperatures from dentulous patients. Sheathed mercury-in-glass thermometers should be decontaminated after each oral use.

In April 1978, a strain of gentamicin-resistant Klebsiella pneumoniae (GRK) was introduced into the neonatal intensive care unit of Henry Ford Hospital. An additional ten cases of GRK occurred over the subsequent 16 months and intestinal colonization occurred in up to 91% of admissions per month. All GRK were susceptible to amikacin and were capsular serotype 19. Though hand contamination of hospital personnel with GRK was documented, increased handwashing practices did not reduce colonization rates of neonates with the epidemic strain. Intestinal carriage persisted for up to ten months and could not be eradicated by administering oral colistin sulfate. Discontinuation of gentamicin and utilization of amikacin were associated with a significant reduction in colonization with GRK (p < 0.05). However, the only control measure that prevented both new cases and colonization with the epidemic strain was the utilization of a strict cohort system.

How often infection rates should be calculated and how large a change is required for “significance” are pertinent questions in nosocomial infection surveillance programs. A method is presented which establishes outbreak threshold infection frequencies. Comparison is direct and immediate: computation of rates or use of electronic data processing is not required. We have validated this method, using computer systems, by comparing the distributions of mean weekly incidence and prevalence statistics for each ward by nosocomial infection site in an acute care general hospital against both our theoretical outbreak threshold limits and the distribution of proven infection outbreaks. Sensitive and specific distinction between random variation or sporadic cross-infection and true persisting outbreaks requiring intervention is obtained. This approach provides a simple and timely alternative to intuitive after-the-fact interpretation of infection patterns which is applicable to infection surveillance and cost-effective infection control in hospitals of all sizes.

During 1981, 39 nosocomial infections occurred in 27 of 223 patients undergoing cardiac surgery in the North Carolina Memorial Hospital. The peak attack rate (23.7%) occurred in August and September compared to 10.1% in January through July. A case-control study demonstrated that the only risk factor common to poor and stable health groups compared to controls was duration of stay in the cardiothoracic intensive care unit (CTICU). Microbiologic studies of the environment, personnel and patients showed that colonization or infection of patients occurred 1 to 6 days after admission to the CTICU and that nosocomial pathogens were found: 1) in and around the unit's soiled utility sink, 2) in pooled handwashing cultures of unit personnel, and 3) on contaminated clean hands and air near the soiled utility sink, plus nearby bedside air only while the water in the sink was running. Environmental and personnel hand contamination by soiled utility sink aerosols likely contributed to these infections. Infection control measures, including discontinued use of the soiled utility sink, resulted in a significantly lower infection rate (5.6%).

Acquired immunodeficiency syndrome, or AIDS, is currently a significant public health problem receiving widespread interest as both cause and treatment are sought. Indications are that a transmissible agent is involved. Both clinical and research laboratories are receiving greater numbers of specimens from AIDS patients as both prevalence of the condition increases and research efforts intensify. Until such time as the causative agent is identified, prudent practice warrants that a high level of precaution be observed. The Division of Occupational and Environmental Health Services of the Yale University Health Services presents a set of safety procedures and guidelines for use by personnel of both clinical and research laboratory facilities. These exceed previously suggested containment recommendations.

In our Intensive Care Nursery, coagulase-negative staphylococcus is the most frequent blood culture isolate. As skin antisepsis is critical in preventing blood culture contamination, we examined the efficacy of the chlorhexidine tincture (CH) used in our nursery for this purpose. Staphylococcus epidermidis colonized the forearms of 88% of infants tested, in a mean density of 104 organisms/cm2. Following a 60-second application of CH (0.5% in 70% ethanol), bacterial growth from forearm skin remained abundant in 15/38 infants (39.4%). Cleansing with 70% isopropyl alcohol, followed by CH as above, left abundant residual growth in only 1/37 infants (2.7%) (P<0.001). All 136 S. epidermidis tested were susceptible to CH (MIC<5(μg/ml) and 14 of 15 exposed to CH 0.02% were rapidly killed (≥98% fall in viable counts within 90 sec). We conclude that two-phase antisepsis using isopropanol followed by CH is a more effective preparation for blood culture in neonates than is CH alone.

Sterile irrigation solutions, used in open systems in a conventional orthopedic operating theatre, were examined for bacterial contamination. At the end of 13 of 21 operations (duration ≥ one hour) the solution tested displayed the growth of Staphylococcus epidermidis and/or diphtheroid rods and/or other species. It is concluded that irrigation by solutions, kept in open bowls during an operation, is a potential source of contamination.

This review of aminoglycoside pharmacology will appear in two parts. The first segment summarizes general information applicable to all agents, such as aspects of absorption, distribution, and clearance. The subsequent article will focus on specific agents currently in use in clinical practice: gentamicin, tobramycin, netilmicin, amikacin, streptomycin, and kanamycin, highlighting toxicities and pharmacokinetic-based dosing strategies.

Embedded in the history of antimicrobial agents with the discovery of streptomycin in 1944, the aminoglycosides remain a mainstay of contemporary antibiotic therapy. Noteworthy features include rapid bactericidal activity against aerobic gram-negative organisms as well as additive or synergistic activity when coadministered with beta-lactam agents. These positive attributes are offset by limited penetration into various body fluids and tissues, and dose (concentration) related renal and ototoxicity. Despite the proliferation of safer beta-lactam compounds with expanded antimicrobial spectrums, the aminoglycosides are still initial drugs of choice for most life-threatening, aerobic, gram-negative infections. Used in combination with anti-pseudomonal penicillins, the aminoglycosides are the agents of choice for empiric therapy of fever in the neutropenic host or documented tissue infection with Pseudomonas aeruginosa.

In 1978 the Ministry of Health and Social Welfare in Liberia embarked on a major initiative to expand immunization activity countrywide. During its early development, the Expanded Program on Immunization (EPI) experienced the realities of establishing an immunization program in a developing country, including the high costs of maintaining mobile operations and a network of kerosene refrigerators. To improve vaccination coverage with diminishing resources, the Program recently began to place greater emphasis on integrating immunization activities into the existing infrastructure of hospitals, clinics, and health posts. Although the EPI goal and objectives, which in retrospect were highly ambitious, have not yet been achieved, it is possible to immunize effectively the children and women of Liberia. Effective vaccination coverage can be achieved by developing local strategies, coordinating resources, and most importantly, involving the community. International organizations must support such efforts by continuing to supplement essential supplies and by promoting research to develop vaccines that are more heat-stable and immunogenic.

In the first issue of Infection Control I discussed hospital infection control committee minutes and reports. Recently there have been cases involving hospital infection control committee minutes and reports, Sherman and Farley infra, and this information should be available to the infection control community. There are also two earlier cases that have bearing as precedents; these four cases will be discussed in chronological order.

Any medical intervention is expected to prevent sickness and complications of a disease rather than to induce them. This is true for therapy as well as prophylaxis. Special formulas have been developed to calculate the risks and benefits of vaccinations simply but with sufficient accuracy. The risk ratio (Q) tells how many times the risk of contracting certain complications or even death from a disease is greater in unvaccinated than in vaccinated individuals. The risk difference (D) directly expresses the number of complications or deaths that may be prevented by a certain vaccination. It is even possible to evaluate the epidemiologic trend of a disease and to calculate or estimate the point of time when the risks of disease and vaccination are just balanced, ie, when a vaccination has lost its beneficial effect. Vaccinations against measles, poliomyelitis and tick borne encephalitis in Austria are highly beneficial. BCG vaccination is still beneficial on a low level in Austria as far as protection against tuberculosis is concerned. This effect will persist for the rest of this century. The benefit of pertussis vaccination depends on the local epidemiologic situation. It has expired for non-risk groups in Austria since 1976 but continues to persist in the US.

The exigency for a comprehensive infectious waste management program in hospitals is influenced by federal guidelines and concern about the public image of our hospitals as a source of environmental pollution. The need to discard infectious waste in an aesthetically acceptable manner that will prevent hazards from injury and/or infection has received some recognition, but many states have not promulgated regulations on infectious waste management. Realizing the critical environmental health problems posed by improper disposal of infectious and other hazardous waste, Congress charged the Environmental Protection Agency (EPA) with the responsibility of formulating “cradle-to-grave” regulations over hazardous waste by requiring implementation of Subtitle C of the Resource Conservation and Recovery Act of 1976. Waste with infectious characteristics that may “pose a substantial present or potential hazard to human health or the environment when improperly … managed” are considered by this Act as hazardous waste. While by definition infectious waste is considered a subset of hazardous waste, the EPA has not yet issued regulations to fulfill the Congressional mandate to establish a management system for infectious waste. It has, however, prepared a technical manual which is intended to assist hospitals and states so they may establish appropriate programs and/or regulations on infectious waste management. This commentary will review some of the principles, practices, problems, products and services associated with infectious waste management.

To determine the cost of post-exposure prevention of hepatitis B among hospital employees, a 12-month prospective study was conducted in six Phoenix-area hospitals. Data on reported employee accidents which involved exposure to blood and any subsequent medical attention were obtained weekly. Costs were assigned to all tests, treatments, and working time lost. For 518 potential hepatitis B exposures, the mean cost per incident was $92. Costs associated specifically with preventing hepatitis accounted for 80% of the costs. When data on these incidents were applied to a model procedure for handling potential exposures to hepatitis B, the costs increased to $109 per incident. One work-related case of clinical hepatitis B cost the hospital $13,376. A determination of total hospital costs for hepatitis B should include the direct and indirect cost of each employee case of the disease, the costs of routine serologic screening of employees, and the cost of post-exposure strategies.

In 1980 an investigation was conducted due to an apparent cluster of fevers following transurethral resections of the prostate (TURP), where the presence of prostatitis or urinary tract infections (UTIs) could not account for most cases, and the usage of antimicrobials did not prevent them. When unused, prepackaged, sterilized samples from 13 lots of triple lumen catheters were analyzed, four were found to contain high levels of endotoxin (ET), with a range of 49,150-≥ 6.25 ng/catheter. Additionally, these lots were highly pyrogenic to rabbits. The maximum incidence of febrile patients (42%) correlated with usage of catheters from the lot where ET levels were the highest. The febrile rate for a second urologist, who used single lumen catheters, was less (12/33 v 0/12). Further consideration should be given to sterile operative equipment which may still be pyrogenic.

Automated peritoneal dialysis systems have helped make intermittent peritoneal dialysis an alternative to hemodialysis for long-term management of patients with end-stage renal disease. However, if not cleaned and maintained properly, these machines provide a reservoir for pathogens. The microbiologic barriers in these machines are not impenetrable, but sterile dialy-sate fluid can be produced if the machines are adequately cleaned and disinfected. Potential shortcomings of the microbiologic barriers are discussed, and guidelines to prevent contamination of the internal parts of a machine are suggested.

The rationale of degerming procedures is the elimination of undesirable microorganisms from sites serving as potential starting points for the transmission of infections, eg, secretions, excretions, and vehicles. The significance of transmission of infection is well-established for some sites, such as the hands, but debatable for others such as surfaces. No general agreement exists on the efficacy of the different procedures used to prevent hospital infections. Since frequently multiple factors intervene and the final effect is due to the interaction of several preventative measures, it is very difficult to ascertain the efficacy of any given procedure. However, to prevent the formation of germ depots outside the organism is a classical postulate of hygiene not yet invalidated.

Rationale and testing of degerming procedures are closely linked. From tests one expects an answer, if and to what extent a degerming procedure fulfills the requirement fixed by the rationale.

It is essential to distinguish between the degerming agent as the active principle and the degerming procedure, which is comprised of additional factors in the application.