Preface

Hospital acquired, or nosocomial, infections are very closely monitored for their prevention and control by regulatory agencies such as the Centers for Disease Control and Prevention and the US Department of Health and Human Services, with an emphasis on patient safety and quality of care. Currently, patient safety and quality of care have become key words. Critically ill patients in intensive care units are at higher risk of multidrug-resistant (MDR) infection. Excessive use of antibiotics, along with a host of multiple co-morbid conditions, predisposes patients not only to MDR infection but also to several atypical infections especially in the immunocompromised host.

Legionnaires' disease is a severe form of pneumonia caused by the bacteria *Legionella*. More than 10,000 patients are hospitalized every year with Legionnaires' disease in the United States alone. It is usually transmitted by inhaling the bacteria, commonly in the form of a mist. Those at risk are individuals with chronic lung conditions and the elderly and immunocompromised. The Legionnaire bacteria thrives in water. Contaminated water system(s) can be the source of infection by inhaling the aerosolized particles or aspiration of the contaminated water.

Legionnaires' disease is also an important public health topic as it involves environmental and public issues as far as spread and prevention are concerned. With an aging population, increasing number of transplants, increasing use of immunosuppressive medications, and compromised immunity due to multiorgan system disease, Legionnaires' disease is emerging as an important disease.

Moreover, extensive research and advances have been conducted in the areas of prevention, diagnostic modalities, and treatment. This book will try to address Legionnaires' disease in the hospital setting, in addition to MDR infection.

#### **Salim Surani, MD, MPH, MSc, FACP, FCCP, FAASM** Adj. Clinical Professor of Medicine, Texas A&M University, Health Science Center, College of Medicine, Texas, USA

Section 1 Introduction

#### **Chapter 1**

## Introductory Chapter: Hospital-Acquired Infection and Legionnaires' Disease

*Salim Surani*

#### **1. Introduction**

According to the Institute of Medicine, hospital-acquired infection and the adverse event in hospitals are responsible for 44,000–98,000 deaths and account for \$17–29 billion in the healthcare cost in the USA alone [1, 2]. The care of the patient in the intensive care unit (ICU) is expensive and poses a significant economic burden on the healthcare [3, 4]. In the early part of the twentieth century, the intensive care units were taking care of patients with respiratory failure related to polio. With the advancement of technology and medicine, patients with multiple comorbidities are now being admitted in the ICU. A study by the World Health Organization (WHO) found that 51% of the patients in the ICU have infections [5]. The risk of infection among patients on a mechanical ventilation is 6- to 21-fold higher. Surprisingly, the risk of ICU-acquired infections among low- and middleincome countries was found to be 2–3 times higher than the ICU-acquired infections among ICU patients in developed countries [5, 6]. With the advent of invasive monitoring and therapeutic devices, the incidence and prevalence of the infection have increased, and we have seen a significant increase in antibiotic use and multidrug-resistant (MDR) infections [7]. Infectious conditions, sepsis, and septic shock continue to be responsible for significant morbidity and mortality [7]. Increased MDR infection has now become a global threat. Two million cases and 23,000 deaths each year are attributable to MDR infection in the USA alone, according to the Centers for Disease Control and Prevention (CDC) [8, 9]. In addition, inappropriate use of the antibiotics not only leads to increase in MDR but costs the healthcare \$27–42 billion annually [8–10]. The central line-associated bloodstream infection (CLABSI) and catheter-associated urinary tract infection (CAUTI) have also been associated with significant nosocomial infection [11]. With significant efforts from the regulatory agency as well as the healthcare organization and providers, a significant decrease in CLABSI and CAUTI has been seen [1, 12]. Education and antibiotic stewardship programs have been recommended by the CDC in 2014. In 2017, a survey by the National Healthcare Safety Network found that the number of hospitals with antibiotic stewardship program (ASP) has increased to 76.4%. Still 25% of the hospitals do not have ASP. As of September 2019, the ASP is required by the Centers for Medicare and Medicaid Services (CMS) as part of the patient care reimbursement. With this new regulatory requirement by the CMS, it is expected that the ASP in hospitals will reach close to 100% [13].

In this book, we will also be addressing Legionnaires' disease in detail. Legionnaires' disease is a bacterial infection caused by Gram-negative bacteria, usually found in freshwater [14]. It can lead to severe pneumonia which can be fatal


#### **Table 1.**

*Selected Legionnaires' disease outbreak in 2019.*

(Legionnaires' disease), but milder and subclinical infection forms (Pontiac fever) do exist [14, 15]. This disease is much more common than we think. Approximately, 10,000 patients are hospitalized every year with Legionnaires' disease in the USA alone. Legionnaires' disease also creates a public health concern. It is usually transmitted by inhaling the mist or via the cooling and water system issues. There have been numerous Legionnaires' disease outbreaks over the decades, and the number seems to be increasing [16]. In the 1970s there were five outbreaks, in the 1980s seven, in the 1990s four, and in the 2000s ten. From 2010 to 2018, there were 23 outbreaks. In the year 2019 alone, there were seven outbreaks (shown in **Table 1**). These reported outbreaks represent just the tip of the iceberg, as not all of them are reported. Moreover, reports from the developing countries are almost nonexistent. The fatalities from Legionnaires' disease range from 0 to 75% [16]. The longevity, multiple invasive devices, increase in transplants, immunocompromised status, aging population, and increase in travels all pose a significant risk of increased outbreaks and high fatality rates. Research and education need to be done in this area. In this book, we will try to address the epidemiology, clinical and therapeutic as it pertains to disease as well as clinical scenario and treatment of Legionnaires' disease among immunocompromised host.

#### **Author details**

Salim Surani

Health Science Center, College of Medicine, Texas A&M University, Texas, United States

\*Address all correspondence to: srsurani@hotmail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Introductory Chapter: Hospital-Acquired Infection and Legionnaires' Disease DOI: http://dx.doi.org/10.5772/intechopen.91373*

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[18] Support LaaMP. 2019. Available from: https://hcinfo.com/about/ outbreaks/recent/
