**4. Nosocomial pneumonia**

In addition, MHD patients usually have problems other than infections, such as cardiovascular or muscle-skeletal disorders. These patients are frequently hospitalized for surgical proce‐ dures or reasons other than infection, where they were treated with various kinds of antibiotics over a long period. These typical clinical courses undergone by MHD patients are known to

As MHD patients get older, they are affected more severely by age-related problems as compared to their counterparts in the general population. Two of the most significant problem are frailty and protein energy wasting (PEW) [2]. This phenomenon is clinically relevant because many manifestations of frailty and PEW are strong risk factors that affect quality of life, morbidity, and mortality. Frailty can be defined as a biological syndrome of decreased resistance to stressors caused by cumulative declines across multiple physiological systems which, ultimately, results in vulnerability to adverse outcomes. Frailty implies decreased body energy, protein reserves and reduced strength. Frailty is a common occurrence in CKD as well as MHD patients. A simple criterion for frailty can be the presence of three or more of the following abnormalities; unintentional weight loss, self-reported exhaustion, measured weakness, slow walking speed, and low physical activity. On the other hand, PEW is defined as the loss of somatic and circulating body protein and energy reserves. The comorbidity of infectious disease is also subject to the influence of these conditions. For instance, sarcopenia and osteopenia puts the patient at risk for falls as well as contracting pneumonia. In regards to aspiration pneumonia (AP), sarcopenia often causes difficulty in swallowing, which leads to unrecognized aspiration. Coordinated muscle movement and optimal muscle strength play an important role in the well-organized swallowing movement. Aspiration status was partly dependent on the lower anterior and posterior esophageal muscle and tongue strength [3]. These muscle strength was imparired by the decline in the global physical status. In ESRD patients under MHD, muscle and energy wasting are prominent, which influences the mortality and morbidity [2]. The tissue changes in muscle varies from morphological, electro‐ physiological and metabolic alterations. These malign changes of muscles lead to muscle weakness and finally to myopathy [4]. Additionally, atrophy of type II fibers was observed in the patients with MHD in several studies. These functional and structural muscle impairments in both systemic and/or oropharyngeal muscle strength are derived from the PEW state in MHD patients. Impaired immune function is associated with PEW in MHD [5]. In addition to an increased susceptibility to infections and poor wound healing, PEW leads to an impaired immune function which affects the gastrointestinal tract malfunction and aberrant microbiota population. These intestinal changes cause malabsorption and malnutrition [6], accelerating further the immune dysfunction. Deterioration in intestinal structure also leads to the en‐ hancement of bacterial translocation in the intestine, leading to systemic inflammation and

PEW involves several mechanisms, including the activation of oxidative stress, the inflamma‐ tory response, and the dialysis measure itself. Several markers of PEW and the resultant

influence the clinical characteristics and microbiological features of pneumonia.

**2. PEW and Frailty in MHD patients**

138 Updates in Hemodialysis

PEW state.

We surveyed 1803 MHD patients admitted to our university hospital between April 2001 and March 2007 [14]. We investigated basic patient characteristics and clinical characteristics of nosocomial pneumonia. The distribution of patient age indicated that about 70% of the patients were over 60 years old. The average length of hospitalization was 28.1 days, ranging from one day to 478 days, which was longer than the average for our hospital (14.2 days). Patients were admitted to different departments for a variety of reasons. We isolated 391 microorganisms from the sputa of 138 patients that were suspected of respiratory tract infections. These include *Candida albicans (C. albicans)*, methicillin-resistant *Staphyloccocus aureus* (MRSA), and *Staphy‐* *loccocus epidermidis* which were the leading three isolates. Among these patients, 47 were diagnosed with pneumonia and 57 pathogens were isolated. From the sputa specimen of pneumonia patients, MRSA and *C. albicans* were most frequently isolated. *Stenotrophomonas maltophilia* (*S. maltophilis*) was also isolated and found to be resistant to older generation cephalosporins, carbapenems, and quinolones. However, new fluoroquinolones, such as levofloxacin, were found to be affective. Among the 138 patients suspected of respiratory tract infections, 15 out of 23 patients infected with *S. maltophilia* died, resulting in the highest mortality among all patients with nosocomial pneumonia examined. With this survey, we concluded that MHD patients suffered from nosocomial pneumonia with multi-drug resistant pathogens. Consequently, *S. maltophilia-*related infections are associated with a high mortality rate and should be taken very seriously.
