Antiseptics and disinfectants. Current issues.

The authors address current issues regarding use of antiseptics and disinfectants with particular emphasis on the problems associated with claims made by manufacturers of various chemical agents. Other issues include the efficacy and limitations of commercial products, selecting the most appropriate formulation for proper disinfection, especially with instruments that come in contact with the patient, and preventing or minimizing iatrogenic infections in clinical practices. The authors stress that low-level and some intermediate-level disinfectants are unreliable because of their narrow safety margin and that chemical agents with a high level of activity should be used by all practitioners because of multi-drug resistant microorganisms and acquired immune deficiency syndrome (AIDS).

Efficacy of disinfectants against fungi isolated from skin and nail infections.

Commercial disinfectants classified as fungicides may not be effective against commonly encountered fungi within reasonable periods. Cell suspensions of clinical fungal isolates were exposed to use-dilutions of various disinfectants. Quaternary ammonium compounds, iodophors, and phenolics were not fungicidal against all test fungi within 60 min of exposure. Trichophyton mentagrophytes, Epidermophyton floccosum, and Aspergillus fumigatus were among the more resistant fungi. Disinfectants that possess low-level activity should not be used for disinfection of medical instruments that come in contact with the patient. The only reliable and safe measure is to use high-level disinfectants such as the glutaraldehydes, which are fungicidal in 15 to 30 min.

The future of podiatric medical education. Cautious optimism.

The leadership of the Pennsylvania College of Podiatric Medicine sets forth the following treatise on the outlook for podiatric medical education into the 21st century. Despite the seemingly impossible challenges facing the profession and its students, it is their opinion that the future is bright and with dedicated effort the profession will become stronger in the years ahead.

Microbiology and antimicrobial therapy of diabetic foot infections.

Infections of the foot in the person with diabetes are the result of a complex myriad of pathophysiologic alterations. Neuropathy, vascular disease, and host immune alterations all interact to present a fertile ground for significant microbiologic invasion. When infection occurs, it is commonly due to a mixed flora of aerobic and anaerobic organisms, although "pure" aerobic or anaerobic infections are sometimes seen. Treatment of these infections requires a broad approach, including surgery, local care, and antibiotics. Most often, treatment against aerobic and anaerobic pathogens will be necessary. These infections can be divided into two categories based on clinical appearance. Severe life- or limb-threatening infections can present with massive cellulitis of the foot and leg, high fever, significantly elevated white blood count, septicemia, and tissue gas. Appropriate antibiotics in this setting include either combination or single-agent therapy. Imipenem/cilastatin offers coverage of all usual pathogens along with potentially lower toxicity and lower cost than combinations. Combinations containing clindamycin and aztreonam or ciprofloxacin may be useful for patients allergic to beta-lactam antibiotics. Less severe infections can usually be treated with a single-agent antibiotic such as ticarcillin/clavulanic acid or ampicillin/sulbactam. Cephalosporins with anaerobic activity, including cefoxitin, cefotaxime, and ceftizoxime, can be used in areas where enterococci are not a major problem.

Quantitative neutralization assay of fungicidal activity of disinfectants.

A quantitative assay using a neutralization medium was developed to evaluate fungicidal activity of disinfectants. Concentrated Dey-Engley neutralizing broth was used in this study and was demonstrated to inactivate various chemical agents within 5 min when disinfectant concentrations were reduced to specific levels. Addition of this Dey-Engley broth to test tubes containing fungal cells and disinfectants permitted control of the various interactions times. Subsequent concentration of the disinfectant-treated cells to a 1-ml final volume also permitted examination of a larger population for the presence of resistant cells. After timed exposures of 15, 30, and 60 min, only three of seven disinfectant solutions were found to be lethal for quantitative populations of 11 fungi tested. The recommended use dilution formulations of a quaternary ammonium product and an iodophor product were the least effective agents. Various fungi, including Trichophyton mentagrophytes, Epidermophyton floccosum, and Aspergillus niger, survived 30- to 60-min interactions with these disinfectant solutions. The most resistant organism encountered was Aspergillus fumigatus, which survived 60 and even 90 min of exposure to most disinfectants. Only use dilutions of a chlorine dioxide formulation, a glutaraldehyde formulation, and an ethyl alcohol product were effective against this species and all of the other fungi after a 15-min interaction.

Tumor-specific transplantation immunity to intracerebral challenge with cells from a methylnitrosourea- induced brain tumor.

Tumor-specific transplantation immunity was demonstrated in syngenic rats immunized and challenged with tumor cells (T9) from an N-methyl N-nitrosourea-induced brain tumor. All unimmunized rats and rats pretreated with normal glial cells in complete Freund's adjuvant or with adjuvant alone died of intracerebral (i.c.) neoplasia at approximately 3 weeks post-challenge. Rats which were immunized with T9 cells with or without adjuvant failed to develop i.c. tumors by 6 weeks even though the challenge dose was 2 logs greater than a dose which consistently resulted in neoplasia in unimmunized rats.

Effect of anticellular serum on the attachment of enteroviruses to HeLa cells.

Anticellular serum (ACS), in the absence of an active complement system, was shown to inhibit the attachment of poliovirus types 1 and 2, echovirus type 6, and coxsackievirus types A13, B1, and B3 to viral receptors of live HeLa cells. This is the first report to provide evidence that ACS has an inhibitory effect on the interaction between host cells and coxsackieviruses of group B. The titer of inhibitory activity of ACS varied inversely with the cell concentration used, the reaction being virtually completed after an incubation period of 30 min at 37 C. The inhibitory activity of ACS persisted for more than 4 hr at 37 C, and was shown to be reversible at pH 2.0, revealing that although the receptors for attaching virus were inactivated by ACS the inactivation was not permanent. These findings are consistent with the concept that antibodies in the ACS combine with and blockade viral receptors located at the cell surface. An antiserum with a specificity for inhibiting attachment of coxsackievirus B1 was obtained by dual absorption of ACS with cells saturated with coxsackievirus type B3 and chymotrypsin-treated cells. These findings offer an approach whereby the antigenic relationship of viral receptors to other constituents of the cell surface can be studied.