Serine racemase binds to PICK1: potential relevance to schizophrenia

Accumulating evidence from both genetic and clinico-pharmacological studies suggests that D-serine, an endogenous coagonist to the NMDA subtype glutamate receptor, may be implicated in schizophrenia (SZ). Although an association of genes for D-serine degradation, such as D-amino acid oxidase and G72, has been reported, a role for D-serine in SZ has been unclear. In this study, we identify and characterize protein interacting with C-kinase (PICK1) as a protein interactor of the D-serine synthesizing enzyme, serine racemase (SR). The binding of endogenous PICK1 and SR requires the PDZ domain of PICK1. The gene coding for PICK1 is located at chromosome 22q13, a region frequently linked to SZ. In a case-control association study using well-characterized Japanese subjects, we observe an association of the PICK1 gene with SZ, which is more prominent in disorganized SZ. Our findings implicating PICK1 as a susceptibility gene for SZ are consistent with a role for D-serine in the disease.

The changing pattern of antibiotic susceptibilities of Bacteroides fragilis in Kuwait

The susceptibility of 340 distinct strains of Bacteroides fragilis isolated during 1981 to 1988, to eight antimicrobial agents was determined. These included isolates from infected hospitalized patients (127), infected out-patients (89), faecal isolates from uninfected patients hospitalized for greater than 10 days (48) and from normal subjects in the community (76). All strains were susceptible to metronidazole with a MIC of 1 mg/l. The least effective antibiotics were ampicillin, fusidic acid, erythromycin and tetracycline. There was no significant difference in antibiotic sensitivities between strains causing community-acquired and those causing hospital-acquired infections. However faecal isolates from hospitalized patients were significantly more resistant to ampicillin (P less than 0.05), cefoxitin (P less than 0.005) and clindamycin (P = 0.001) than community faecal isolates. During the study period there was a rise in resistance to clindamycin (P less than 0.005), cefoxitin, erythromycin and fusidic acid (P less than 0.001) and tetracycline (P less than 0.05). Antimicrobial resistance of B. fragilis is rising and long periods of hospitalization seem to play an important role in its development.

Septicaemia in a teaching hospital in Kuwait--I: Incidence and aetiology

During a period of 18 months of study, blood cultures were performed on 3845 patients in hospital with clinical signs of infection. Among these, 214 (5.6%) episodes of septicaemia were diagnosed which correspond to 10.9/1000 hospital admissions. About 80% of the episodes were due to Gram-negative organisms, most common of which were Escherichia coli (19.6%), Salmonella spp (16.5%) and Klebsiella spp (15.1%). Gram-positive organisms implicated in 20% of episodes were mainly Staphylococcus aureus (9.3%) and enterococci (4.9%). Of all the septicaemias 62.0% were community-acquired with Salmonella spp. being the organism most commonly implicated. Hospital-acquired infections were mainly due to Serratia spp, Pseudomonas spp and Flavobacterium spp. The antibiotic resistance pattern of the organisms showed that hospital-acquired organisms had relatively high resistance to most antibiotics as compared with community-acquired organisms.