oa Editorial from Guest Editors [Hot Topic: Pulmonary Infections in Critical Care (Guest Editors: Matt P. Wise and Anton G. Saayman)]

This issue of Current Respiratory Medicine Reviews is dedicated to pulmonary infections in critical care and an ensemble of international experts have been brought together to review this important subject. Meeting new challenges in the management of pulmonary infections in the critically ill requires a greater understanding of pulmonary defence mechanisms, pathogenesis and diagnosis of infection, so that new strategies can be employed whilst at the same time making better use of currently available drugs. Nationwide trends demonstrate that an ever-increasing number of patients are being admitted to hospital with sepsis syndromes. Although absolute numbers of patients dying from sepsis are rising, this has been tempered by a reduction in mortality rates [1-3]. An ageing population with comorbid disease, more frequent use of indwelling medical devices and immunosuppression all contribute to the observation of an increase in sepsis. In the SOAP study, which examined sepsis in 198 European intensive care units, the most frequent site of infection was the lung and was present in two thirds of patients on arrival to critical care [4]. Community-acquired pneumonia remains an important reason for admission to both hospital and critical care and continues to rise, partly in response to an ageing population [5-7]. An additional burden on critical care capacity is posed by healthcare-associated pneumonia (HCAP), hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP) which are frequently caused by organisms with bacterial resistance to multiple antibiotics and consequently higher treatment failure rates are often observed. Emergence of multidrug resistant organisms amongst community-acquired infections is a further area of concern [8]. New and emerging infections, which are often first identified in critically ill patients, pose an additional encumbrance [9, 10]. Erosion of the antimicrobial armamentarium is unfortunately set against a backdrop of a limited pipeline of new antimicrobial drugs coming into clinical practice. Wilkinson and colleagues review the complexity of pulmonary defence mechanisms that repel respiratory pathogens continually accessing the airway. They explore how an understanding of host immunity can improve vaccination strategies and lead to novel therapies. Williams et al. discuss the importance of the oral cavity in the pathogenesis of VAP and how an understanding of biofilm biology is fundamental to both the aetiology of VAP and developing new preventative therapies. Young and Doyle examine the central role of the endotracheal tube in VAP and how improvements in tube design may prevent its occurrence. Diagnosing VAP remains a challenge for the physician and the inability to accurately identify patients with VAP has undoubtedly hampered research in this area [11]. In their review Grover and colleagues discuss how established and novel biomarkers might enhance diagnostic certainty. Clinicians frequently focus on bacterial infections in the critically ill but are now realising that other organisms pose an increasing burden particularly in those with prolonged periods of ventilation. Linssen et al. discuss the impact of latent viral infections in mechanically ventilated patients, whilst Barnes reviews pulmonary fungal infections, which are often difficult to both diagnose and treat. The first influenza pandemic in over 40 years was caused by a novel influenza A strain, A(H1N1)pdm09 and this had a huge impact on critical care across the globe, including the postpandemic period. Dunning and Openshaw describe the clinical features of this disease and the treatment options available. Iannella and Luna consider the impact and aetiology of treatment failure in VAP including host, bacterial, and therapeutic factors. Complementary to this Dhanani and colleagues review how antibiotics may be optimally used including alternate modes of administration, continuous infusions, therapeutic drug monitoring and combination therapy. Poulakou et al. examine the burden and treatment options for Methicillin-resistant Staphylococcus aureus (MRSA), which is no longer limited to being a nosocomial pathogen. Notwithstanding the armamentarium available to physicians in modern healthcare systems, pulmonary infections will continue to present a challenge for critical care physicians and patients alike....