Performance Evaluation of the Verigene Gram-Positive and Gram-Negative Blood Culture Test for Direct Identification of Bacteria and Their Resistance Determinants from Positive Blood Cultures in Hong Kong.

BACKGROUND: A multicenter study was conducted to evaluate the diagnostic performance and the time to identifcation of the Verigene Blood Culture Test, the BC-GP and BC-GN assays, to identify both Gram-positive and Gram-negative bacteria and their drug resistance determinants directly from positive blood cultures collected in Hong Kong. METHODS AND RESULTS: A total of 364 blood cultures were prospectively collected from four public hospitals, in which 114 and 250 cultures yielded Gram-positive and Gram-negative bacteria, and were tested with the BC-GP and BC-GN assay respectively. The overall identification agreement for Gram-positive and Gram-negative bacteria were 89.6% and 90.5% in monomicrobial cultures and 62.5% and 53.6% in polymicrobial cultures, respectively. The sensitivities for most genus/species achieved at least 80% except Enterococcus spp. (60%), K.oxytoca (0%), K.pneumoniae (69.2%), whereas the specificities for all targets ranged from 98.9% to 100%. Of note, 50% (7/14) cultures containing K.pneumoniae that were missed by the BC-GN assay were subsequently identified as K.variicola. Approximately 5.5% (20/364) cultures contained non-target organisms, of which Aeromonas spp. accounted for 25% and are of particular concern. For drug resistance determination, the Verigene test showed 100% sensitivity for identification of MRSA, VRE and carbapenem resistant Acinetobacter, and 84.4% for ESBL-producing Enterobacteriaceae based on the positive detection of mecA, vanA, blaOXA and blaCTXM respectively. CONCLUSION: Overall, the Verigene test provided acceptable accuracy for identification of bacteria and resistance markers with a range of turnaround time 40.5 to 99.2 h faster than conventional methods in our region.

Phenotypic features in a boy with monosomy 18 mosaicism.

We report on a patient with mosaicism for monosomy 18, a chromosomal abnormality that has been reported only once previously. The patient had cleft lip and palate and mild behavioral and academic problems. His phenotype was milder in comparison with the previously reported patient by Khalifa et al. [1996: Clin Genet 49:318-320]. Further case reports of this chromosomal anomaly will be needed to determine a consistent phenotypic pattern to assist in management and genetic counseling.

Report of a new patient with transposition of the great arteries with deletion of 22q11.2.

We report on a new patient with d-transposition of the great arteries who was found to have deletion of 22q11.2. He had minor facial anomalies, normal T- and B-cell subsets, and transient hypocalcemia. Similar to rare previous reports, our patient's extracardiac manifestations were relatively mild.

Trisomy 1q43 syndrome: a consistent phenotype with macrocephaly, characteristic face, developmental delay and cardiac anomalies.

Trisomy 1q43 syndrome: a consistent phenotype with macrocephaly, characteristic face, developmental delay and cardiac anomalies: Patients with trisomy (1)(q42-qter) present with psychomotor retardation, macrocephaly, occasional presence of facial capillary naevi, cardio-vascular anomalies and small size for gestational age. We report on a girl with the same pattern of malformations, who has pure trisomy 1 q43: duplication of the region (1) (q43) and the translocation of the terminal region of the other chromosome 1 to the derivative 1, narrowing down the critical region for the characteristic traits of severe developmental delay, macrocephaly and congenital cardiac malformations.

Galactosemia: clinical features, diagnosis and management. A case report.

The case report and discussion presented here were prepared in response to legislation in Louisiana which requires that the Dept of Health and Hospitals establish a program to inform physicians and hospitals of the current medical standards for the diagnosis, clinical management, and recognition of galactosemia. Classical galactosemia is an inborn error of galactose metabolism caused by a deficiency of galactose-1-phosphate uridryl transferase. It is inherited as an autosomal recessive trait and its estimated occurrence is 1/60,000. The presenting symptoms which include vomiting, diarrhea, jaundice, and failure to thrive result from the ingestion of foods containing galactose--breast milk and formulas containing cow's milk. Although some states routinely screen all newborns for galactosemia, the results of the newborn screening are often not available before the infant presents with symptoms. Early recognition and immediate withdrawal of galactose from the diet can prevent serious morbidity and mortality. There is significant clinical variability and not all infants present with typical acute manifestations of the disease.

Long-term outcome in treated combined methylmalonic acidemia and homocystinemia.

PURPOSE: To describe the clinical and biochemical features and long-term outcome of a cohort of eight patients with methylmalonic acidemia and homocystinuria (cblC). METHODS: Documentation of clinical features at birth and longitudinal follow-up of the biochemical and clinical response to treatment with daily oral carnitine and intramuscular hydroxocobalamin observed during continuous follow-up for an average of 5.7 years. RESULTS: Our patients had an increased incidence of congenital malformations including microcephaly (<5%) at birth (2 of 8), congenital heart disease (2 of 8), dysmorphic facial features (1 of 8), and thyroglossal duct cyst (1 of 8). Postnatal hydrocephalus (2 of 8) and hip dislocation caused by ligament laxity (1 of 8) were also noted. One patient had profound visual impairment before 6 months of age secondary to cblC retinopathy, and two patients had abnormal retinal pigmentation with normal visual function. All patients presented with poor growth, feeding problems, and/or seizures. No patients had acute acidotic crises before or after treatment. All patients had dramatic reduction of plasma free homocystine and urine methylmalonic acid excretion after initiation of therapy with carnitine, intramuscular (IM) hydroxocobalamin (OHcbl) and, in two cases, oral betaine. Growth was significantly improved in most cases after the initiation of therapy, and microcephaly was resolved in one patient. All patients were developmentally delayed regardless of age of treatment onset, although two patients had relatively mild developmental delay. CONCLUSION: cblC patients may have an increased incidence of congenital malformations suggesting prenatal effects of abnormal cbl metabolism. Treatment with IM OHcbl and carnitine successfully corrects the biochemical abnormalities and improves growth. Developmental delay of variable severity is always present regardless of age at diagnosis or treatment onset.

Characterization of a cystathionine beta-synthase allele with three mutations in cis in a patient with B6 nonresponsive homocystinuria.

We used SSCP to survey reverse transcribed-PCR amplified cystathionine synthase cDNAs from patients with homocystinuria. In a single CBS allele, we identified one synonymous and two missense mutations in a portion of the cDNA encoded by a single 135 bp exon which also encodes K119, the putative site of cofactor, pyridoxal 5'-phosphate, binding. The patient, a B6-nonresponsive homocystinuric of Irish descent, is homozygous for a G-->A transition at cDNA position 374, a G-->A transversion at position 393, and a G-->A transition at position 453 resulting in R125Q, E131D and P145P, respectively. Family studies confirmed that all three mutations are present in cis and none were present in 54 Irish and 58 North American controls. R125 is conserved in rat CBS while E131D is conserved in rat CBS, and a related enzyme, O-acetylserine(thiol)-lyase, from a variety of plant and bacterial species. Expression studies showed that both R125Q and E131D, either individually or together, inactivate CBS. The apparently simultaneous appearance of more than one mutation in a single exon suggests they may have arisen by a gene conversion event or by nonhomologous recombination.

The isolation of cDNAs from OATL1 at Xp 11.2 using a 480-kb YAC.

Using an ornithine-delta-aminotransferase (OAT) cDNA, we identified five YACs that cover two nonadjacent OAT-related loci in Xp11.2-p11.3, designated OATL1 (distal) and OATL2 (proximal). Because several retinal degenerative disorders map to this region, we used YAC2 (480 kb), which covers the most distal part of OATL1, as a probe to screen a retinal cDNA library. From 8 x 10(4) plaques screened, we isolated 13 clones. Two were OAT cDNAs. The remaining 11 were divided into eight groups by cross-hybridization. Groups 1-4 contain cDNAs that originate from single-copy X-linked genes in YAC2. Each has an open reading frame of > 500 bp and detects one or more transcripts on a Northern blot. The gene for each was sublocalized and ordered in YAC2. The cDNAs in groups 5-8 contained two or more Alu sequences, had no open reading frames, and did not detect transcripts. The cDNAs from groups 1-4 provide expressed sequence tags and identify candidate genes for the genetic disorders that map to this region.

A novel disease with deficiency of mitochondrial very-long-chain acyl-CoA dehydrogenase.

Palmitoyl-CoA dehydrogenase activity in skin fibroblasts from seven patients with unidentified defects of fatty acid oxidation was measured in the presence and absence of antibodies against medium-chain, long-chain, and very-long-chain acyl-CoA dehydrogenases (VLCAD). Two of the patients, 4-5 month old boys, were found to have a novel disease, VLCAD deficiency, as judged from the results of very low palmitoyl-CoA dehydrogenase activity and the lack of immunoreactivity toward antibody raised to purified VLCAD.