In 1899, Thiercilin used the term “enterococcus” to describe microscopic organisms seen in pairs or short chains in feces. Later (in the 1930s) the name was used in a more restrictive sense for streptococci that had the hardy capacity to survive under extreme conditions.

Enterococci belong to a group D family of streptococci, as characterized by Lancefield in 1938. In contrast to other groups of streptococci, the group D antigen is not a wall carbohydrate but a glycerol teichoic acid containing glucose and D-alanine. This antigen appears to be related directly to the cytoplasm or plasma membrane.

The frequency of handwashing in two intensive care units (ICUs) was observed. Handwashing after direct contact with patients or their support equipment was recorded. The ratio of beds to sinks was 1:1 in the medical ICU and 4:1 in the surgical ICU. Surveillance of physicians, nurses, and other personnel demonstrated a greater frequency of handwashing by nurses (63%) compared with physicians (19%) and other personnel (25%). The nurses in the unit with one sink per bed had a significantly greater number of handwashes (76%) than those in the unit with fewer sinks (51%).

The skin is itself the site of infection by many different bacteria. Dermatologists may see primary skin infection due to Staphylococcus aureus, beta hemolytic streptococci and a host of less common pathogens including gonococci, mycobacteria and even enterobacteriaceae, or secondary infection which is mostly staphylococcal in eczema or weighted toward Proteus and Pseudomonas in venous stasis ulcers. Geriatricians see a mixed microbial flora in decubitus ulcers while those who insert plastic prostheses, intravenous or abdominal catheters can expect infection with coagulase-negative or positive cocci.

The skin also forms a natural reservoir of organisms available to infect a variety of patients and it is with the skin as a reservoir that this article is concerned. The normal flora of the skin in healthy subjects is composed chiefly of coagulase-negative cocci and coryneforms with gram-negative bacilli chiefly, but not entirely, represented by Acinetobacter. Patients admitted to the hospital who are severely ill may become more heavily colonized by gram-negative bacilli while frank skin lesions constitute a more obvious source of potential pathogens.

In many hospitals, waste materials and used linens from the rooms of patients in isolation or the clinical laboratories are routinely double-bagged to reduce contamination of the external surface of the bag that could be transmitted to hospital personnel subsequently handling them. No studies have prospectively examined the value, if any, of double-bagging. We randomly assigned waste and linens from the rooms of 42 patients in contact isolation to be transported in single bags or double bags. Shortly after a single (or double) bag had been set outside the patient's room, the surface was cultured quantitatively in two locations near the knot; over 2 months, 209 bags were cultured. Surface contamination by Staphylococcus aureus (3% to 5%), enteric gram-negative bacilli (6% to 7%), or either (9% to 12%) was infrequent and comparable in both groups; moreover, quantitative levels of contamination in the two groups were almost identical (mean, 27 and 29 colony forming units [cfu] per bag). These data suggest that there is no advantage, as regards asepsis, to double-bagging potentially contaminated items from isolation rooms or clinical laboratories as compared with using a single bag. The use of a single-bag system with a heavyduty bag, as compared with double-bagging, saved our hospital $9,400 in 1985.

Whereas infections of the skin per se comprise only a fraction of all institutionally-acquired infections, the skin has become one of the most important reservoirs of nosocomial pathogens in the hospital. Professor Noble has provided a scholarly review of the increasing importance of the major constituents of the cutaneous microflora as nosocomial pathogens and what we know of their epidemiology. Unfortunately, the empiricism and limited scientific data which underlie essential infection control measures in this area, particularly in regard to cutaneous antisepsis and handwashing, is almost incongruous in an era in which controlled clinical trials have dominated most other areas of medicine. The numerous outbreaks traced to contaminated antiseptics and disinfectants over the past two decades, stand as mute testimony to the inadequate investigative attention this area has received.

Thirty-two clinical specimens submitted to the laboratory during a 12-month period from July 1980 to June 1981 were reported to be culture-positive for Mycobacterium gordonae, an organism generally considered to be a slow-growing saprophyte with natural habitats which include soil and water. Only seven similar isolates had been recovered in the preceding 4½ year period. The discordance between clinical findings and the mycobacterial cultures suggested extrinsic contamination of the specimens. Contamination in the laboratory was believed unlikely because: 1) clinical samples obtained in an aseptic manner were never contaminated; 2) various surveillance cultures of reagents and deionized water used in the laboratory were negative; and 3) substitution of deionized water with sterile water did not control the outbreak. Extensive hospital-wide cultures of water sources implicated the use of ice and ice water from contaminated ice machines as the source of this pseudoepidemic. Cleaning of the ice machines resulted in a sharp decrease in the number of M. gordonae isolates. Pseudoinfection by M. gordonae from improperly maintained ice machines has not been reported before.

In recent years there have been great advances made in antiviral therapy. One of the most promising of the new agents to be introduced is acyclovir. This antiviral, which selectively inhibits the replication of particular DNA viruses, is being used clinically in the treatment and prevention of viral infections caused by several of the herpes viruses. Though not a cure, acyclovir can be effective for the management of symptoms associated with these infections. Since acyclovir acts only on replicating viral DNA, the drug has no effect on the latent virus which establishes itself in neural tissue. This makes eradication of the virus very difficult.

On May 17, 1984, a 67-year-old woman with endometrial carcinoma underwent an uneventful abdominal hysterectomy. Suddenly, 18 hours later she was in septic shock, short of breath, restless and oliguric. The wound appeared intact without erythema. Intraabdominal sepsis was postulated and the patient was given full dosages of intravenous cefotaxime, metronidazole and netilmicin. At 48 hours postoperative, the abdominal wound showed areas of necrosis and the patient died. The wound, peritoneal fluid, urine and blood yielded group A (β-hemolytic streptococci (Streptococcus pyogenes). Shortly before death, intravenous penicillin had been administered. An epidemiologic study was promptly initiated.

The responses to a comprehensive survey of infection control practices for respiratory therapy equipment, previously published in the Readers' Forum section of Infection Control, are summarized in Tables 1 through 3. Responses were obtained from 205 United States hospitals; 65% were community hospitals and 38% had <500 ventilator days/year. In some cases, the total number of responses exceeded 100% because of practices that required multiple responses.

A national effort to reduce nosocomial infections includes a program developed at the National Institutes of Health to encourage handwashing in hospitals and day care centers. The program promotes a symbolic teddy bear (T. Bear) with slogans to remind hospital personnel and patients to practice handwashing. One of the items used is a stuffed toy T. Bear to be dispensed to the hospitalized child. Considering the manner in which children handle stuffed toys, we suspected the T. Bear might serve as a “fomite” for transmission of nosocomial microbes. A prospective study of 39 sterilized T. Bears revealed that all became colonized with bacteria, fungi, or both within 1 week of hospitalization. Hospital acquired organisms cultured from the T. Bear included Staphylococcus epidermidis, Staphylococcus aureus, alpha streptococci, Corynebacterium acnes, Micrococcus sp, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Bacillus sp, and species of Candida, Cryptococcus, Trichosporon, Aspergillus and others. Concomitant cultures of the patients revealed similar isolates. Although the T. Bear handwashing campaign should not be discredited, the promotional toy may pose an unnecessary expense and hazard and should not be used in hospitals or day care centers.

Forty subjects participated in a study of four handwashing agents evaluated for their efficacy in removing non-transient bacteria: 70% isopropanol, 0.05% stabilized iodine, 4% chlorhexidine gluconate, and 1% para-chloro-meta-xylenol. Each subject performed a non-medicated handwash to remove transient flora. Afterwards, three consecutive experimental handwashes were performed using a 10-second contact time, and a fourth handwash employed a 1-minute contact time. Quantitative post-handwash cultures were obtained using the sterile bag technique incorporating an effective agent neutralizer. Significant mean log10 reductions were documented for chlorhexidine gluconate, but only after the third (P=.05) and fourth (p=.004) handwash; however, the total log10 reduction was less than 1.0 for any single agent.

Subsequently, three evaporative handwash agents, including 70% isopropanol, 0.5% chlorhexidine in 70% isopropanol, and a 60% isopropanol formulation containing evaporative retardants, were tested in 14 subjects. Contact time was prolonged to the point of evaporation prior to culturing. Four consecutive post-handwash cultures were obtained after performing a baseline pre-handwash culture. When compared with the other two evaporative agents, the 60% isopropanol formulation demonstrated significant mean log10 reductions for each handwash (p ≤ .03), with a total log10 reduction of 2.9 over all four handwashes (p=.0001). The brief contact time incorporated in our handwashing technique reflects clinical usage patterns. The marked bacterial reduction demonstrated by the 60% isopropanol formulation warrants further study.

In Bergey's manual, animal and human corynebacteria are a group of aerobic and facultatively anaerobic gram-positive or slightly curved bacilli that are generally nonmotile, catalase-positive, and non-acid fast. The best known and most clinically significant pathogen in the genus Corynebacterium is C. diphtheriae. However, other members of this genus are frequently encountered in the clinical laboratory and usually represent colonization or commensal contamination, since most other corynebacteria are of low virulence and questionable clinical significance. Frequently described as “diphtheroids,” such organisms are usually dismissed as contaminants and are not speciated or subjected to susceptibility testing. The JK diphtheroids may be differentiated from clinically unimportant “diphtheroids” by their resistance to beta-lactam antibiotics and their distinctive morphologic and cultural characteristics (Table 1).

The authors modified the Centers for Disease Control's guideline for disease-specific isolation precautions to a hospital computerized information system. Entering a suspected diagnosis selected from the isolation option on computer terminals generated: 1) a printout listing the isolation instructions, infective material(s), and persons who should avoid exposure; 2) an order for the appropriate supplies; 3) a patient charge based on the supplies required; and 4) an option for stopping, changing, or listing the orders. In order to implement this system, both extensive in-service training for nurses and efforts to change ordering practices of physicians were necessary.

Prevalence surveys before and after computerization were used to evaluate the new system. Combined surveys showed that isolation was ordered for only 21% of patients when indicated. Failure to isolate was identified as a significant problem. As a consequence, continuous surveillance and consultation of all infected patients were instituted, resulting in isolation orders for 81% when indicated. The computerized disease-specific system has resulted in better and more accurate use of isolation, probably due to in service education and surveillance efforts.

A prevalence study was carried out on a 100-bed Veterans Administration nursing home care unit to determine the extent of colonization with gentamicin-resistant gram-negative bacilli (GRGNB). Hand cultures of 12 employees and 17 environmental cultures were negative. Twenty-six of 86 (30%) patients were colonized with 49 GRGNB. Sixteen patients (19%) had urinary colonization. Multivariate analysis revealed significant associations between rectal or perineal colonization (P<0.01), and the presence of a urinary device (82% condom catheters) (P<0.05), with urinary colonization. The most common isolates were Providencia stuartii (20), Escherichia coli (nine) and Klebsiella pneumoniae (nine). Twenty-six of 49 isolates carried plasmids. Restriction endonuclease digestion of plasmid DNA was performed for 21. Cross-colonization, as defined by the presence of the identical species with the identical restriction endonuclease digestion profile of purified plasmid DNA found in different patients, was observed for eight of 21 (38%) strains. All were geographically clustered. No strains could transfer gentamicin-resistance by conjugation and only two plasmids could transform our E coli recipient to gentamicin resistance. One E coli plasmid was identical to two Citrobacter freundii plasmids and a P stuartii plasmid isolated from three different patients. This 105 kb plasmid is conjugative and encodes resistance to ampicillin, carbenicillin, tetracycline, and sulfonamides. Thus, 57% of strains were cross-colonizing or contained identical R-plasmids. Southern hybridization using a 1 kb TEM-1 gene probe demonstrated sequences homologous to this probe in five of five nursing home plasmids examined. These data demonstrate the utility of plasmid analysis in epidemiologic typing of multiple species of Enterobacteriaceae, and suggest wide dissemination of R-plasmids bearing the TEM-1β-lactamase gene among gram-negative bacilli colonizing patients residing in our nursing home.

Herpes simplex virus (HSV) causes a variety of illnesses in th e community and hospital settings (Table). Nosocomial infections with this virus may result from: 1) reactivation of latent infection, especially in patients whose immune systems are compromised; 2) spread from mother to infant; 3) spread from patients to hospital personnel; 4) spread from hospital personnel to patients; and 5) cross-infection among patients. The latter two possibilities seem to occur infrequently but merit some discussion because of the serious implications of such infections.

In the past 15 years, our knowledge of the pathogenesis and etiologic agents of diarrheal disease has expanded rapidly. No longer is it scientifically appropriate or cost effective for the laboratory simply to culture a stool for Salmonella and Shigella and to do a wet mount for amebae. Today we have a plethora of agents including, but not limited to, Campylobacter, Yersinia, Clostridium difficile, Escherichia coli, Aeromonas, Plesiomonas, vibrios, rotavirus, Norwalk agent, Giardia, and Cryptosporidium, which have all been suggested to be agents of diarrheal disease. Given such a wide range of possibilities, what approaches should be taken to determine the etiologic agent of diarrheal disease in the hospitalized patient in an era of cost containment?

Imipenem, a new carbapenem ß-lactam broad-spectrum antibiotic, is highly active in vitro against most aerobic and anaerobic gram-positive and gram-negative bacteria isolated from infectious diseases of human beings. Except for enterococci and methicillin-resistant staphylococci most gram-positive cocci are inhibited by <2 μg/ml. Although the MIC-90 of methicillin-resistant staphylococci may be <4 μg/ml, these bacteria are usually resistant to imipenem by modified testing methods. The enterococcus, S. faecalis, has an MIC-90 of <8 μg/ml but bactericidal concentration may be much higher. Most Enterobacteriaceae are highly susceptible to imipenem with MIC-90 of 0.5 to 2.0 μg/ml. Proteus species are less susceptible with MICs of 4 to 8 μg/ml. Isolates of P. aeruginosa have variable susceptibility with MICs ranging from 0.25 to 16 μg/ml. Pseudomonas maltophilia and P. cepacia are usually resistant to imipenem. Except for Clostridium species, most strict anaerobes are susceptible to <1.0 μg/ml of imipenem. When combined with cilastatin (1:1 ratio), the renal elimination of the active form is increased. The serum half-life in normal renal function is about 1 hour and increases to 3.4 hours in anuria. Major adverse effects are similar to those of cephalosporins except for seizures in some patients. Colonization with fungi and drug-resistant bacteria occurs in about 5% of imipenem-treated patients. Clinical studies have demonstrated efficacy in 79% to 96% of patients treated.

Review of all hepatitis B surface antigen-positive patients reported to the county health department over the past 3 years showed that 60% of patients had been diagnosed at our hospital, which serves an inner city, predominantly black, indigent population. Sera from 524 adult patients admitted to the hospital were prospectively collected and tested for hepatitis B surface antigen, eight (1.5%) of which were antigen-positive. Census tract data allowed us to perform selective screening of sera from 95 other patients who were subsequently hospitalized and deemed “high risk” for hepatitis B infection. Nine of 95 (9.5%) selectively screened samples were positive for hepatitis B surface antigen, which represented a significantly higher rate of antigen carriage (P<0.0001) in hospitalized patients from “high risk” areas than that found in the general population screen. The methodology presented herein may be useful in providing a means of identifying hepatitis B surface antigen-positive patients from adult, urban, indigent care populations.