Cluster of postinjection abscesses related to corticosteroid injections and use of benzalkonium chloride.

Benzalkonium chloride (BC) is an unreliable disinfectant. A matched case-control study and environmental investigation were conducted to determine the cause of and risk factors for a cluster of postinjection abscesses at a private medical clinic where BC was used as a disinfectant. Twenty-eight case-patients who had an abscess at the injection site were matched with 126 control patients who had received an intramuscular injection at the clinic on the same day. Risk factors for abscess development in a multivariable logistic model were corticosteroid injection and being female. All case-patients had received a corticosteroid injection from a multidose vial. Cultures of abscesses from 20 of 23 case-patients grew Pseudomonas aeruginosa. Cultures of BC prepared at the clinic also grew P aeruginosa, suggesting that BC was the source of infection. Injection site cleaning with BC did not appear to be the route of infection since use of BC at the time of injection was not associated with abscess development. A more likely route of infection was injection of contaminated corticosteroid from multidose vials that could have been inoculated with pseudomonads via needle puncture after vial septa were wiped with contaminated BC. Benzalkonium chloride should not be used to clean injection vial septa or injection sites.

Bacterial/fungal growth in a combined parenteral nutrition solution.

Appropriately mixed, compatible solutions of glucose, amino acids and lipid have recently become available for clinical use. While a single hyperalimentation solution has several advantages over the conventional two-bottle technique, its effect on infusion-related septicemia is unknown. An in vitro, mock infusion system identical to that used in our new-born intensive care unit was set up to assess the relative growth rates of three microorganisms in several parenteral nutrition mixtures. Growth of Staphylococcus epidermidis, Escherichia coli and Candida albicans was measured in seven different alimentation solutions, including two combined solutions. Generally, microbial growth was the same or decreased in combined solutions as compared to fat alone although considerably greater than that observed in nonlipid containing solutions. In addition, the ability of these organisms to pass in-line terminal filters of pore size 0.22 and 1.2 microns was assessed.

A clinical evaluation of chlorhexidine gluconate spray as compared with iodophor scrub for preoperative skin preparation.

In a prospective, randomized study, 737 patients who were evaluated had the operative site prepared preoperatively by either a 0.5 per cent chlorhexidine gluconate spray or povidone-iodine scrub. The wound infection rate in these two comparable groups was not statistically different, although slightly favoring the spray technique (6.0 versus 8.1 per cent). The spray technique challenges the conventional preoperative scrub and offers further advantages of increased effectiveness while also offering savings of time and expense.

Recurrent urban histoplasmosis, Indianapolis, Indiana, 1980-1981.

In January 1981, informal surveillance of acute histoplasmosis in Indianapolis, Indiana, revealed a marked increase in disease activity for the last quarter of 1980. Fifty-one patients with onset of acute histoplasmosis during this period were identified through review of hospital admissions, emergency room visits, and serologic records at Indianapolis hospitals and the Indiana State Board of Health. In a retrospective case-control study, the authors found a significant association between developing acute histoplasmosis during this period and working or attending classes in a 2 sq mi (5.2 sq km) area encompassing the Indiana University-Purdue University campus (p = 0.015, Fisher's exact test). A review of construction activities on or near the campus during the epidemic period suggested that the probable source of infection was excavation activity for a large new indoor swimming complex (natatorium). Skin tests and serosurveys of students on campus by a newly developed radioimmunoassay for histoplasmal immunoglobulin M antibodies supported the association of infection with exposure to this site (p less than 0.05).

The diagnostic laboratory tests for histoplasmosis: analysis of experience in a large urban outbreak.

Of 495 patients reported in a large urban histoplasmosis outbreak, we studied 276 whose serologic tests were done in a single laboratory. Serologic test results were positive in 96% of these patients (compared with less than 5% of controls from an endemic area), cultures were positive in 22%, and special stains in 19%. The immunodiffusion test results were negative in 13% of patients who had positive findings by complement fixation, and 1% had positive results only by immunodiffusion. The complement fixation test was almost twice as sensitive as the immunodiffusion test in patients with subclinical infection. The serologic response differed significantly among the clinical syndromes with higher titers in cavitary and lower titers in disseminated disease. Factors associated with titers of 1:64 or greater to both antigens were black race and immunocompetence. High mycelial titers were also associated with more intense exposure, and high yeast titers were associated with age less than 36 years. No prognostic significance could be proved for fourfold titer rises or falls or persistence of precipitins.

Risk factors for disseminated or fatal histoplasmosis. Analysis of a large urban outbreak.

An outbreak of histoplasmosis in Indianapolis involving 488 clinically recognized cases including 60 patients with disseminated or fatal infection permitted statistical analysis of risk factors. Being male, white, under 5 years of age, having chronic obstructive lung disease, and living near the presumed source of the outbreak were not risk factors for fatal or disseminated histoplasmosis. Age greater than 54 years and immunosuppression were the only risk factors for disseminated or fatal infection. Dissemination should be excluded in patients with histoplasmosis who are immunosuppressed or older than 54 years. Specific antifungal treatment is more likely to be required in those two groups rather than in patients without risk factors.

Should linen in newborn intensive care units be autoclaved?

The American Academy of Pediatrics' Standards and Recommendations for Hospital Care of Newborn Infants recommends that linen in newborn intensive care, intermediate care, continuing care and admission observation areas be autoclaved. Questionnaires sent to 269 directors of newborn intensive care units (69% returned) showed that 74% of the respondents do not autoclave linen used in their newborn intensive care unit. There were 284 linen cultures performed in our newborn intensive care unit where linen is not autoclaved; 68% of the cultures were positive, but only 2.5% had a colony count greater than 20 colonies per plate. The most common organisms obtained were Staphylococcus epidermidis, diphtheroids, and Micrococcus species. Two cultures grew Staphylococcus aureus, one colony and two colonies per plate. Three-factor analysis of variance showed that the location of the linen in the top of the pile exerted a statistically significant effect on the bacterial contamination rate. The fact that three fourths of neonatal intensive care centers in this country do not autoclave nursery linen, the lack of reports in the literature relating linen contamination to nosocomial infections, and the microbiologic results of this study suggest that the recommendations of the American Academy of Pediatrics merit further study and reevaluation.

A large urban outbreak of histoplasmosis: clinical features.

An outbreak of histoplasmosis estimated to involve more than 100,000 residents in Indianapolis, Indiana, occurred between September 1978 and August 1979. In the 435 cases evaluated, 52% of the patients were between 15 and 34 years old, and 63% were black. Fifteen patients died, and 46 progressive disseminated infection. Twenty-four patients had pericarditis, and 26 had rheumatologic syndromes. Unusual manifestations that occurred in 18 patients included esophageal and vocal cord ulcers, parotitis, adrenal insufficiency, uveitis, fibrosing mediastinitis, interstitial nephritis, intestinal lymphangiectasia, and epididymitis. The highest attack rate was in the central part of the city, which is a densely populated, disproportionately black section. The source of the outbreak has not been proved by positive culture results; two sites, however, were suspected on an epidemiologic basis.

The surgeon's garb.

A comprehensive evaluation of all factors associated with the surgeon's garb worn with and without laminar air flow revealed that in a conventional operating room, all personnel should wear an impermeable one-piece suit with foot attachments, any type of head cover, and, if they are going to be near the operative site or instrument table, a disposable mask. Scrub personnel should wear some type of a disposable gown to reduce the amount of surface contamination. The best way to reduce the environmental and surface contamination would be for all personnel to wear some type of a hooded exhaust equipment, but this is impractical both for circulating nurses and for anesthesiologists. Despite the reduction obtained from all the above controls, the reduction in the amount of bacterial contamination would not be as great as that obtained with laminar air flow, 93% (p < 0.005). Laminar air flow produced the greatest single reduction in environmental and surface contamination and variables such as time, people and attire did not influence the overall counts. The attire recommended for the conventional operating room can be used in laminar air flow with an expectation of overall reduction in contamination.

The antimicrobial effectiveness of operative-site preparative agents: a microbiological and clinical study.

Eight wound preparative agents (one triclosan compound, one hexachlorophene compound, and six iodophors) were evaluated under actual operating-room conditions for efficacy in de-germing the operative site prior to the performance of 310 total hip arthroplasties. All of the preparations tested achieved a significant reduction (p less than or equal to 0.001) of indigenous skin microflora compared with the pre-scrub level in both the post-scrub and the postoperative cultures. Two iodophors, when applied as sprays, demonstrated excellent bactericidal action, were less time-consuming and easier to use than the compounds that were applied as scrubs, and did not alter the low (0.42 per cent) infection rate that we have recorded over a period of four years.

Bacterial contamination potential of sterile, prefilled humidifiers and nebulizer reservoirs.

Contaminated respiratory therapy equipment may be responsible for the spread of pathogens to hospital patients. This study focused on the potential for contamination of prefilled, sterile, disposable water and saline systems for humidification and nebulization. Gas and liquid samples from 48 prepacked oxygen humidifier/cannula and 26 prepacked nebulization setups were taken at the initial application of devices and at 8, 24, 48, and 72 hour intervals, totaling 386 cultures. All samples from the humidifier units were found to be pathogen-free for up to 3 days. A total of six or 3.84% of the nebulizer samples showed contamination with Enterobacter cloacae after 8 to 24 hours of operation. It was concluded that the potential for contamination of the humidifiers is low for up to 72 hours, but the nebulizer units should be changed after 24 hours even though their contamination rate is markedly lower than that of conventional nondisposable units.

A microbiological in-use comparison of surgical hand-washing agents.

Seven different surgical hand-scrub agents (one triclosan compound, two hexachlorophene compounds, and four iodophors) were evaluated under in-use conditions by five persons for efficacy in degerming the hands and forearms prior to performing a total of 215 total hip arthroplasties. With all of the compounds tested there was a significant reduction (p less than or equal to 0.001) of indigenous skin microflora from prescrub levels at both the post-scrub and postoperative points. The two hexachlorophene compounds in general revealed a bacteriostatic effect whereas the triclosan compound and the four iodophors did not. A hexachlorophene compound applied as a foam demonstrated excellent bacteriocidal and bacteriostatic action, was less time-consuming and easier to use than compounds applied as scrubs, and did not alter a low (0.47 per cent) in-use infection rate over a period of three years.

Comparison of horizontal and vertical unidirectional (laminar) air-flow systems in orthopedic surgery.

The microbiological evaluation of a horizontal walled unit, a horizontal wall-less unit and a vertical wall-less unidirectional airflow unit revealed a statistical reduction in the wound and back table air settle plate counts for the 2 horizontal systems as compared to the vertical system.

The effect that time, touch and environment have upon bacterial contamination of instruments during surgery.

Hemostats were evaluated for frequency of contamination and such contamination was correlated with increasing operating room exposure time. The studies were performed under surgical conditions in operating rooms with and without laminar air flow. The study was also designed to show whether contamination of hemostats were influenced by the scrub nurse's handling. Hemostats were more frequently contaminated in the conventional operating room without laminar air flow (P less than 0.001). Handling by the scrub nurse's gloved hand statistically increased the number of contaminated hemostats (P less than 0.01). Laminar air flow reduced the frequency of contamination statistically (P less than 0.001) to a point where time and touch by a gloved hand of the scrub nurse were not important factors.

The plastic surgical adhesive drape: an evaluation of its efficacy as a microbial barrier.

A microbial evaluation was made of adhesive plastic surgical drapes and cloth surgical drapes. These studies were done both during surgery and in the laboratory. The plastic drape does not allow bacterial penetration, lateral migration does not occur, skin bacteria do not multiply under the drape within the time periods studied and the patient drapes are held in place with their use. When wet, cloth drapes showed profuse bacterial penetration. Dry cloth showed less bacterial penetration as compared to wet cloth. Lateral migration under cloth drapes was not possible to assess due to a high level of penetration. The surface of cloth showed a higher level of bacterial contamination during the surgical procedures. Deep wound cultures collected just prior to closing showed 60% contamination when cloth was used compared to 6% when plastic was employed. The micro-organisms recovered from the various sites sampled were identified. Finally, in addition to the positive aseptic benefits afforded by plastic adhesive drapes, aesthetic features such as a more delineated operative field and elimination of towel clips make this product a useful adjunct to the surgeon's armamentarium.

Bacterial contamination of the surgical knife.

Two hundred and eight skin knives and 374 deep knives were evaluated in 153 clean orthopedic cases with and without a horizontal wall-less laminar air-flow system. There was no statistical difference in contamination frequency between the skin and the deep knives with and without the laminar air-flow. However, the knife blades were found to be contaminated less than laminar air-flow was used than when it was not (P less than 0.005). No correlation could be made between the cultures of the wound edges and the depth of the wound with the contaminated knife blades.

Rodac plate-holding device for sampling surfaces during surgery.

A Rodac plate-holding device has been developed to facilitate microbial surface sampling of supposedly sterile items in the operating room during surgery.