Consulting-Specifying Engineer - September 2007 - (Page 29)

uch attention has been focused recently on pathogenic microorganisms and the threat these microorganism are to communities. Especially problematic are microorganisms that have developed resistance to antibiotic treatment and that have begun to spread beyond the bounds of hospital walls. The most dangerous are those that may spread by the airborne route, which include methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant tuberculosis (XTB). Pathogens that develop pan-drug resistance (PDR) might be considered “superbugs” because they are virtually invulnerable to standard drug treatments. Once these microbes develop immunity to antibiotic treatment and cause outbreaks in hospital environments they may, and have on occasion, spread into local communities. How great an epidemic threat these microorganisms are to communities is a question worth examining in more detail. M Airborne nosocomial infections Nosocomial, or hospital-acquired, infections have been around as long as hospitals have been operating. But it is only in the last few decades that antibiotic and other treatments for these diseases have begun failing (ASM, 1994). The failure of any treatment leads to further spread if the infection cannot be contained by other means, such as quarantine. Airborne epidemics can spread rapidly and pervasively through a non-immune population (Weinstein, 2004). Thanks to favorable indoor environments airborne epidemics tend to be self-perpetuating, as opposed to foodborne and waterborne epidemics, which tend to be local and short-lived. Most of the drug-resistant pathogens circulating today are capable of airborne transmission (Kowalski, 2006). Table 1 identifies all of the nosocomial agents that may transmit at least partly by the airborne route, and these include bacteria, viruses, and fungi (Kowalski 2006). These microbes are ranked by estimated order of occurrence and are classified as contagious, noncontagious and endogenous (present as part of normal human flora). The primary infections caused are identified, including surgical site infections (SSI). Because the types of drug treatment differ between these three groups, the nature of the drug resistance also varies. But one factor is common to all these microbes—increasing drug resistance tends to facilitate their multiplication and spread, sometimes beyond the bounds of hospital walls. The reasons for the resurgence of infectious diseases are complex and include factors such as increased urbanization and crowding, environmental changes, and worldwide commerce and travel (Pimentel et al, 1998, Platt, 1996) contribute to the resurgence. Some specific causes are population growth and an enormous number of susceptible people living in poor and crowded urban areas, inadequate and deteriorating public health infrastructures worldwide and misuse of antibiotics or other drugs, which can hasten the evolution of resistant microbes (Ewald, 1994). Misusing drug includes prescribing them without proper indications, prescribing the wrong drugs or the wrong doses and having poor patient compliance with treatment regimens (WHO “World Heath Organization Fact Sheet No. 194”). Bacteria that cause respiratory infections have been developing increased drug resistance over the past few decades (WHO “World Heath Organization Fact Sheet No. 194”). Other non-respiratory bacteria have experienced the same drug-resistance and increasing incidence. Viral respiratory pathogens represent a significant fraction of nosocomial infections and are subject to rapid evolutionary change (Ewald, 1994). Fungal pathogens also have been on the rise recently, in part due to the prevalence of immunodeficiency diseases that facilitate their spread (Ampel, 1996). The public often imagines that doctors have unlimited arsenals of weapons to fight microbial infections, but in fact, there are a mere A C E F H L P WLADYSLAW J. KOWALSKI, P.E., PH.D, Executive vice president, Immune Building Systems, Inc., New York Superbugs: Can Hospital-Acquired Infections Cause Community Epidemics? Consulting-Specifying Engineer • SEPTEMBER, 2007 29

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - September 2007

Contents M/E Roundtable Cover Story: Airborne Superbugs Third-Party Liability Back to School Product Spotlight Codes & Standards Professional Practices How To New Products Jobs/Cliassifieds Specifier’s Notebook Pure Power Supplement New Technologies, Same Old Transmission Problems Wireless Battery Recharging Solar Concentration Renewables Tracking System A Mighty Wind The Importance of Load Bank Testing Quality Power for Security Systems

Consulting-Specifying Engineer - September 2007

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