Legionella species colonization of water distribution systems, pools and air conditioning systems in cruise ships and ferries.

BACKGROUND: Legionnaires' disease continues to be a public health concern in passenger ships. This study was scheduled in order to investigate Legionella spp. colonization of water distribution systems (WDS), recreational pools, and air-conditioning systems on board ferries and cruise ships in an attempt to identify risk factors for Legionella spp. colonization associated with ship water systems and water characteristics. METHODS: Water systems of 21 ferries and 10 cruise ships including WDS, air conditioning systems and pools were investigated for the presence of Legionella spp. RESULTS: The 133 samples collected from the 10 cruise ships WDS, air conditioning systems and pools were negative for Legionella spp. Of the 21 ferries WDS examined, 14 (66.7%) were legionellae-positive. A total of 276 samples were collected from WDS and air conditioning systems. Legionella spp. was isolated from 37.8% of the hot water samples and 17.5% of the cold water samples. Of the total 96 positive isolates, 87 (90.6%) were L. pneumophila. Legionella spp. colonization was positively associated with ship age. The temperature of the hot water samples was negatively associated with colonization of L. pneumophila serogroup (sg) 1 and that of L. pneumophila sg 2 to 14. Increases in pH >/=7.8 and total plate count > or =400 CFU/L, correlated positively with the counts of L. pneumophila sg 2 to 14 and Legionella spp. respectively. Free chlorine of > or =0.2 mg/L inhibited colonization of Legionella spp. CONCLUSION: WDS of ferries can be heavily colonized by Legionella spp. and may present a risk of Legionnaires' disease for passengers and crew members. Guidelines and advising of Legionnaires' disease prevention regarding ferries are needed, in particular for operators and crew members.

Sleep apnoea syndrome and early stage cirrhosis: a pilot study.

OBJECTIVES: Hepatic encephalopathy in patients with end-stage liver cirrhosis is associated with alterations in sleep patterns. Cirrhosis may also affect pulmonary function and it might be involved in the development of obstructive sleep apnoea syndrome (OSAS) in patients with ascites. We carried out a study to evaluate the presence of OSAS in cirrhotic patients without evidence of ascites (early stage cirrhosis). METHODS: We investigated 20 patients with Child A or B cirrhosis (19 and one, respectively) and 10 non-cirrhotic patients with chronic viral hepatitis (disease control group). All subjects were interviewed and underwent a thorough physical examination, a full polysomnographic study and a pulmonary function testing by spirometry. Serum samples were also obtained in order to determine the liver function tests. RESULTS: The presence of OSAS and inverted sleep patterns was similar in cirrhotic patients and disease controls. However, significant correlations were revealed between age and hypopnoeas per hour of sleep; age and the Apneas/Hypopneas Index (AHI); age and FEV1/FVC; gamma-glutamyl transpeptidase and FEV1/FVC; and total bilirubin and total sleep time. CONCLUSIONS: Early stage cirrhosis is not associated with sleep disorders and OSAS. However, total bilirubin levels might be a useful laboratory marker for early assessment of disturbance in sleep patterns and therefore of subclinical hepatic encephalopathy in Child A cirrhosis.

Antioxidant capacity in obstructive sleep apnea patients.

OBJECTIVES: Obstructive sleep apnea syndrome (OSA) results in oxygen desaturation and arousal from sleep. Free oxygen radicals are highly reactive molecules, which can be produced by the OSA phenomenon known as hypoxia/reoxygenation. Hypoxic conditions, such as OSA, may also result in transient depletion of cellular reductants, which constitute a main line of antioxidant defense. Both apneas and hypopneas usually end in arousal, where reoxygenation causes the production of reactive oxygen species (free radicals). Living organisms have developed complex antioxidant systems to counteract reactive oxygen species and to reduce their damage. We evaluated the antioxidant capacity in serum from OSA patients and healthy people in order to confirm the hypothesis that there is a relationship between oxidative stress and OSA. MATERIALS AND METHODS: A physician interviewed 25 participants, determining age, smoking habits and symptoms such as excessive daytime sleepiness and snoring. Physical examination and polysomnography were performed during patients' hospitalization. Antioxidant capacity was measured in blood samples by Trolox Equivalent Antioxidant Capacity assay. RESULTS: Seventeen out of 25 subjects had an apnea/hypopnea index (AHI) greater than 10 (OSA group). The measurement of antioxidant capacity did not differ between the OSA patients and our healthy sample (of 25 subjects, seven with an AHI less than 10). Furthermore, patients with severe OSA (AHI >20, N=14) had linearly negative correlation between antioxidant capacity in their blood samples and AHI (R=-0.551, P=0.041). CONCLUSIONS: Reduced antioxidant capacity in serum is an index of excessive oxidative stress. Patients with severe OSA have reduced values of antioxidant capacity.

Reactive oxygen metabolites (ROMs) as an index of oxidative stress in obstructive sleep apnea patients.

STUDY OBJECTIVES: Obstructive sleep apnea syndrome (OSA) is accompanied by oxygen desaturation and arousal from sleep. Free oxygen radicals are highly reactive molecules which could be produced by the OSA phenomenon of hypoxia/reoxygenation: cyclical alterations of arterial oxygen saturation with oxygen desaturation developing in response to apneas followed by resumption of oxygen saturation during hyperventilation. On the basis of these considerations, it was hypothesized that OSA may be linked to increased oxidative stress. MATERIAL AND METHODS: Twenty-six participants gave an interview during which a physician asked them about their age, smoking habits, and symptoms such as excessive daytime sleepiness and snoring. Physical examination and polysomnography were performed during their hospitalization. Reactive oxygen metabolites (ROMs) were measured in blood samples by the diacron reactive oxygen metabolites (D-ROM) test. RESULTS: Twenty-one out of 26 subjects had an apnea/hypopnea index greater than 5 (OSA group). The measurement of free radicals was high in OSA patients. Furthermore, ROMs values in OSA patients were linearly correlated with the apnea/hypopnea index (R = 0.426; p = 0.042). The predictive value of a positive D-ROM test is 81%. CONCLUSIONS: ROMs were elevated in patients with OSA. When OSA was severe, similarly the value of ROMs in blood samples was enhanced, and the probable underlying mechanism for these events is the hypoxia/reoxygenation phenomenon.