J Med Microbiol

Comparative phenotypic characteristics of Staphylococcus aureus isolates from line and non-line associated septicaemia, CAPD peritonitis, bone/joint infections and healthy nasal carriers.

Year 1998
Al-Wali WI. Elvin SJ. Mason CM. Clark A. Tranter HS.
Department of Medical Microbiology, Northern General Hospital, Sheffield.
This study compared specific phenotypic and potential virulence characteristics of Staphylococcus aureus isolates from invasive infections and nasal carriers. Three hundred and sixty isolates were studied; 154 from septicaemia (69 line associated, 85 non-line), 79 from continuous ambulatory peritoneal dialysis (CAPD) peritonitis, 64 from bone/joint infections and 64 from healthy nasal carriers. The isolates were tested for production of enterotoxins (SE) A, B, C or E, toxic shock syndrome toxin-1 (TSST-1) protein A, and also for lipolytic, proteolytic, fibrinolytic and haemolytic activities. In addition phage typing, crystal violet reaction, urease and galactose breakdown were studied. Seventy-one percent of isolates were enterotoxigenic. Production of SEA was significantly lower amongst the bone/joint isolates. Production of SEB, was lower among the control group compared with CAPD, bone/joint, and non-line septicaemia isolates. SEE production was higher among the bone/joint isolates compared with the CAPD and non-line septicaemias and production of TSST-1 was significantly higher among nasal isolates compared with isolates causing infection. Almost all of the isolates were lipolytic, with highest activity amongst nasal and bone/joint isolates. Fibrinolytic activity was similar in the five groups of isolates. Proteolytic activity ranged from 35 to 62% of isolates with the lowest frequency among septicaemia isolates. In all, 80-90% of isolates were haemolytic, although CAPD isolates were less likely to be haemolytic. Isolates from the control and CAPD group more frequently belonged to phage group I. TSST-1 does not appear to be an important requirement for invasive infections, but SEB may be. Proteolysis and intensity of lipolysis appear to be less important in septicaemia, and haemolysis may not be important in CAPD peritonitis.

The 18th C.L. Oakley Lecture. Pathogenicity of enteropathogenic Escherichia coli.

Year 1998
Baldwin TJ.
Institute of Infections and Immunity, School of Clinical Laboratory Sciences, University Hospital, Queen's Medical Centre, Nottingham.
Enteropathogenic Escherichia coli (EPEC) remain an important world-wide cause of diarrhoeal disease and mortality of infants and young children. Research programmes around the world have, in recent times, made enormous strides towards a better understanding of EPEC pathogenesis, yielding unique insights into the molecular intercourse between host and pathogen. Recombinant DNA and cell biology techniques have provided powerful tools, giving the first intriguing glimpses of a wealth of bacterial products mediating complex host:pathogen interactions involving the subversion of normal host signalling processes. Much has been discovered since 1945, when E. coli was first implicated as a cause of diarrhoea. However, many questions remain unanswered and many more remain unasked. Much remains to be discovered, especially in the area of molecular interactions between host and pathogen and how they relate to the manifestation of disease in the patient.