Does screening neonates in the neonatal intensive care unit for Pseudomonas aeruginosa colonization help prevent infection?

BACKGROUND: Pseudomonas aeruginosa (PA) is a Gram-negative environmental organism that can cause severe infection in immunosuppressed patients, including preterm neonates. In recent years, it has become common practice to screen neonates for PA colonization. AIM: To assess the value of screening neonates for PA in (1) predicting the risk of developing severe PA infection and (2) directing infection control practice. METHODS: Between August 2012 and September 2015, babies admitted to the neonatal intensive care unit (NICU) at North Bristol NHS Trust were screened routinely for PA colonization on admission and weekly thereafter. Data were also collected on babies who developed PA infection. Environmental samples from the NICU were tested for the presence of PA. Variable number tandem repeat (VNTR) typing was performed on all strains of PA from babies and the environment. FINDINGS: No babies with positive screens subsequently developed PA infection. There was no VNTR strain evidence supporting cross-infection from the environment or other babies. CONCLUSION: Screening neonates for PA did not identify babies who subsequently developed PA infection. Following cessation of screening in September 2015, there was no increase in the number of babies identified with PA infection.

A comparison of diagnostic methods for the detection of bovine respiratory syncytial virus in experimental clinical specimens.

Virus shedding was monitored in nasal secretions of 12 calves experimentally infected with bovine respiratory syncytial virus (BRSV) using an antigen capture enzyme-linked immunosorbent assay (ELISA) detecting the nucleoprotein (NP) antigen of BRSV, by a polymerase chain reaction (PCR) amplifying the fusion protein of BRSV, and by a microisolation assay combined with immunoperoxidase staining for the F protein of BRSV. Under the conditions of this study, similar limits of detection and quantitative results were obtained from all three assays. BRSV was detected in nasal secretions of all calves for a minimum of 4 d. Virus shedding began on Day 2 after infection, peaked on Days 3-5, and was cleared in most calves by Day 8. The PCR, and to a lesser extent the ELISA, may detect virus shedding for a longer period after infection than virus isolation, possibly due to neutralization of the virus by rising mucosal antibody. Simulated environmental conditions likely to be experienced during transport of clinical field specimens markedly reduced the sensitivity of virus isolation but had a minimal effect on the results of the NP ELISA. Actual field transport conditions (overnight on ice) had minimal apparent effect on the results of the PCR assay. The less stringent specimen handling requirements, combined with low limits of detection, of both the nucleoprotein ELISA and PCR, indicate either of these assays are more suitable for diagnostic applications than virus isolation.

DNA repair proficiency: a potential marker for identification of high risk members in breast cancer families.

Breast cancer is the single largest cancer and causes the high rate of cancer mortality among women. A positive family history of breast cancer is recognized as one of the major risk factors for this disease. The present study evaluates bleomycin (BLM)-induced chromosome sensitivity analysis in breast cancer families which provides indirectly a measure of the DNA repair defect of each person. BLM sensitivity assay on cultured lymphocytes of 36 familial breast cancer patients, their 85 first or second degree female relatives, 36 sporadic breast cancer patients and 40 age- and sex-matched controls (without any family history of cancer) were carried out to measure interindividual variation in their DNA repair capacity through mutagen-induced chromosome sensitivity analysis. Fifty percent of familial breast cancer patients and seven unaffected relatives showed hypersensitivity. Compared to hyposensitive relatives these seven subjects may be considered as high risk individuals.

The cytogenetic identification of high risk members in colorectal cancer families.

Family history of colorectal cancer is recognized as a risk factor for the disease and the development of colorectal cancer represents a suitable model for illustrating multistep tumor development. Bleomycin induced chromosome sensitivity studies were done in 7 colorectal cancer families consisting of 12 colorectal cancer patients and their 34 first degree relatives and 12 sporadic colorectal patients for comparison and identification of high risk family members with genetic instability. All patients and 4 unaffected relatives showed increased bleomycin sensitivity, which might be due to defective DNA repair system. These four relatives may be classified as high risk (without cancer at present) individuals. The study is being continued in more number of familial colorectal cancer patients and their relatives to arrive at definite conclusions.

Genetically engineered synthesis of precorrin-6x and the complete corrinoid, hydrogenobyrinic acid, an advanced precursor of vitamin B12.

BACKGROUND: Genetically engineered synthesis, in which the gene products, cofactors, and substrates of a complete pathway are combined in vitro in a single flask to give the target, can be a viable alternative to conventional chemical construction of molecules of complex structure and stereochemistry. We chose to attempt to synthesize the metal-free corrinoid hydrogenobyrinic acid, an advanced precursor of vitamin B12. RESULTS: Cloning and overexpression of the genes necessary for the S-adenosyl methionine dependent conversion of 5-aminolevulinic acid (ALA) to precorrin-3 and those required for the synthesis of hydrogenobyrinic acid from precorrin-3 completed the repertoire of the 12 biosynthetic enzymes involved in corrin synthesis. Using these enzymes and the necessary cofactors, the multi-enzyme synthesis of hydrogenobyrinic acid from ALA can be achieved in 20% overall yield in a single reaction vessel, corresponding to an average of at least 90% conversion for each of the 17 steps involved. CONCLUSIONS: By replacing the cell wall with glass, and by mixing the soluble biosynthetic enzymes and necessary cofactors, the major segment of the physiological synthesis of vitamin B12 has been accomplished. Since only those enzymes necessary for the synthesis of hydrogenobyrinic acid from ALA are supplied, none of the intermediates is deflected from the direct pathway. This results in an efficiency which in fact surpasses that of nature.