ABSTRACT

Respiratory infections are one of the major health problems. Lower respiratory infections were the fourth leading cause of death worldwide and the top leading cause of death in the low-income countries in 2012 (WHO 2014). In 2012, approximately 3.1 million lives were taken by lower respiratory infections. Besides the high mortality and morbidity rates, respiratory infections are also responsible for increasing nancial burden to the healthcare system (Birnbaum et al. 2002). The discovery of antibiotics has saved billions of lives from infections, including those occurring in the airways. However, since the 1990s, there has been a marked decline in the discovery of new antibiotics, and unfortunately, this is accompanied by a signi- cant increase in resistance to current antibiotics. We are facing a growing threat from the emergence of bacteria that are resistant to almost all available antibiotics (Boucher et  al. 2013). Antimicrobial resistance has been identied by the World Health Organization as one of the three greatest threats to human health (Infectious Diseases Society of America 2010).