Tap out: reducing waterborne Pseudomonas aeruginosa transmission in an intensive care unit.

BACKGROUND: Pseudomonas aeruginosa is a ubiquitous and important opportunistic pathogen in immunocompromised or critically ill patients. Nosocomial P. aeruginosa outbreaks have been associated with hospital water sources. AIM: To describe engineering interventions to minimize contamination of water outlets and the subsequent clinical impact. METHODS: New tap outlets were fitted at selected outlets across the intensive care unit (ICU). Laboratory testing demonstrated that, following artificial contamination with P. aeruginosa, these taps could be effectively decontaminated using a thermal washer-disinfector. Water samples were collected weekly from new outlets on the ICU over an eight-month period and tested for the enumeration of P. aeruginosa via membrane filtration. Surveillance of P. aeruginosa from clinical specimens was routinely undertaken. FINDINGS: Prior to the interventions, water sampling on ICU indicated that 30% of the outlets were positive for P. aeruginosa at any one time, and whole genome sequencing data suggested at least 30% transmission from water to patient. Since their installation, weekly sampling of the new tap outlets has been negative for P. aeruginosa, and the number of P. aeruginosa clinical isolates has fallen by 50%. CONCLUSION: Installation and maintenance of tap outlets free of P. aeruginosa can substantially reduce the number of P. aeruginosa clinical isolates in an ICU.

Unmasking leading to a healthcare worker Mycobacterium tuberculosis transmission.

BACKGROUND: Mycobacterium tuberculosis is a major health burden worldwide. The disease may present as an individual case, community outbreak, or more rarely as a nosocomial outbreak. Even in countries with a low prevalence such as the UK, tuberculosis (TB) presents a risk to healthcare workers (HCWs). AIM: To report an outbreak which manifested 12 months after a patient with pulmonary tuberculosis was admitted to Queen Elizabeth Hospital Birmingham. METHODS: We present the epidemiological and outbreak investigations; the role of whole genome sequencing (WGS) in identifying the outbreak and control measures to prevent further outbreaks. FINDINGS: Subsequent to a diagnosis of open TB in a patient, transmission was confirmed in one HCW who had active TB; HCWs with latent TB infection (LTBI) were also identified among seven HCW contacts of the index patient. Of note, all the LBTI patients had other risk factors for TB. Routine use of WGS identified the outbreak link between the index patient and the HCW with active TB disease, and informed our investigations. CONCLUSION: Exposure most likely occurred during an aerosol-generating procedure (AGP) which was done in accordance with national guidance at that time without using respiratory protection. Enhanced control measures were implemented following the outbreak.

Use of genome sequencing to identify hepatitis C virus transmission in a renal healthcare setting.

BACKGROUND: Hepatitis C virus (HCV) infection is a major health burden worldwide. A patient with no history of HCV infection while on a renal unit was found to seroconvert to HCV. AIM: To report the use of sequencing to postulate how transmission of HCV occurred in a healthcare setting, and how this guided our outbreak investigation. FINDINGS: Based on infection control inspections the transmission event was surmised to be due to ward environmental contamination with blood and subsequent inoculation from intravenous interventions on the patient acquiring HCV. We discuss the interventions put in place in response to the outbreak investigation findings. CONCLUSION: Sequencing of healthcare-acquired HCV infections should be undertaken as routine practice in outbreak investigations.

Humour experience in schizophrenia: relationship with executive dysfunction and psychosocial impairment.

BACKGROUND: The ability to appreciate humour is essential to successful human interactions. In this study, we hypothesized that individuals with schizophrenia would have diminished ability to recognize and appreciate humour. The relationship between humour experience and clinical symptoms, cognitive and social functioning was examined. METHOD: Thirty patients with a DSM-IV diagnosis of schizophrenia were compared with 30 age-, gender-, IQ- and ethnicity-matched healthy controls. Humour recognition was measured by identification of humorous moments in four silent slapstick comedy film clips and calculated as d-prime (d') according to signal detection theory. Humour appreciation was measured by self-report mood state and funniness ratings. Patients were assessed for clinical symptoms, theory of mind ability, executive function [using the Wisconsin Card Sorting Test (WCST)] and social functioning [using the Life Skills Profile (LSP)]. RESULTS: Patient and control groups did not differ in the funniness ratings they attributed to the video clips. Patients with schizophrenia had a lower d' (humour) compared to the controls, after controlling for (1) the performance of a baseline recognition task with a non-humorous video clip and (2) severity of depressive symptoms. In patients, d' (humour) had significant negative correlation with delusion and depression scores, the perseverative error score of the WCST and the total scores of the LSP. CONCLUSIONS: Compared with controls, patients with schizophrenia were less sensitive at detecting humour but similarly able to appreciate humour. The degree of humour recognition difficulty may be associated with the extent of executive dysfunction and thus contribute to the psychosocial impairment in patients with schizophrenia.

DNA adducts and induction of sister chromatid exchanges in the rat following benzo[b]fluoranthene administration.

Benzo[b]fluoranthene (B[b]F) was administered (100 mg/kg by i.p. injection) to male Sprague--Dawley rats. Lungs, livers and peripheral blood lymphocytes (PBLs) were harvested 1, 3, 5, 7, 14, 28 and 56 days after treatment. Several DNA adducts were observed in each tissue, with maximal levels occurring at approximately 7 days after treatment. Lung DNA exhibited consistently higher adduct levels than liver or PBL DNA. At 56 days after B[b]F administration, the adducts in liver and PBL DNA were present at < 10 amol/microgram DNA, while in lung there were 100 amoles/microgram DNA. No significant differences were observed between tissues in the types of adducts produced. Co-chromatography with synthetic standards showed that only a minor adduct produced in vivo is derived from trans-9,10-dihydro-9,10-dihydroxybenzo[b]fluoranthene-11,12-oxide. Sister chromatid exchanges (SCEs) from whole blood cultures were significantly increased relative to concurrent controls between 1 and 14 days after B[b]F administration, with maximum levels at 14 days. By 28 days after treatment, SCEs had essentially returned to control levels. SCE induction did not correlate with the amount of B[b]F--DNA adducts remaining in the PBLs at harvest time.

Accelerated mental aging in alcoholic patients.

Discriminant function and polynomial regression methods were used to define a mental age function from scale score profile patterns found in the WAIS manual. Values on the mental age function then were calculated from WAIS scale score profiles for 164 alcoholics in the age range 35 to 74. Validity of the mental age function was evident in clear discrimination between chronological age groups in the alcoholic sample. As compared with WAIS normative values for the mental age function, the mean mental age for patients in the alcoholic sample was advanced approximately 7 years over age-matched normals. Unweighted means ANOVA revealed the accelerated mental aging of alcoholic patients to be statistically significant. This finding is discussed in the context of other research that supports a premature aging hypothesis.