Margaretha Isaäcson

Investigation of contaminated parenteral nutrition fluids associated with an outbreak of Serratia odorifera septicaemia

An outbreak of fatal septicaemia caused by Serratia odorifera biotype 1 involved infants at several hospitals; the common vehicle of infection was contaminated parenteral nutrition fluid. The transfusate had been made up in a flexible film isolator system. The implicated organism was recovered from surfaces inside the isolator, despite routine decontamination procedures having been carried out shortly before. Our investigation into the origin of contamination revealed several shortcomings in the infusate compounding process. We noted deficiencies in cleaning and decontamination procedures, and in storage and sterility testing policies, but the origin and mechanism of the contamination were unclear. Withdrawal of parenteral nutrition products and revision of decontamination procedures terminated the outbreak. The efficacy of peracetic acid treatment of flexible film isolators, given the circumstances of this outbreak, may need further investigation. Regular training and assessment of admixture technicians is important.

Sporotrichosis following a rodent bite

A ten year old boy developed lymphocutaneous sporotrichosis following a wild rodent bite. The infection was successfully treated with potassium iodide. Sporotrichosis in humans has followed bites, pecks and stings inflicted by a variety of animals, birds and insects. Many species of animals are susceptible to infection by Sporothrix schenkii, but transmission from infected animals to man is uncommon.

Effect of iron and pH on the survival of Vibrio cholerae in water

Many physicochemical factors affect the survival of Vibrio cholerae in the aquatic environment. An attempt was made to study the combined effect of pH and iron on the survival of V. cholerae in water in a laboratory environment. None of the 6 strains of V. cholerae used survived at pH 5.0; survival of all strains increased with increasing pH. The effect of ferric oxide on survival was significant for V. cholerae O1 only, not for non O1 strains. The longest survival of V. cholerae non O1 was 82 d, of El Tor V. cholerae 68 d, and of classical V. cholerae 56 d.

The effect of iron on the survival of Vibrio cholerae O1 in dechlorinated tap water

Many factors, such as temperature, pH, organic nutrients, types of water storage containers, etc., determine the survival of Vibrio cholerae in water. Since the survival of V. cholerae O1 has been shown to be much longer in metal drums used as household water storage containers than in clay pots and plastic drums, the present study was designed to explore the possible role played by insoluble iron on the survival of V. cholerae O1 in water. The possibility of iron acting as particulate matter for the organisms to adhere to was also examined by using inert glass beads in water. Survival of V. cholerae O1 in dechlorinated tap water, with and without inert glass beads, ranged from < 24 h to 10 d. The number of surviving bacteria was, however, very low. In the presence of impure ferric oxide (Fe2O3), survival in tap water ranged from 4 to 12 d and the numbers of surviving bacteria were very high. Iron was thought to play an important role in the survival of V. cholerae O1 in water. Differences between the numbers of bacteria and the length of survival in surface water and in sediment were unremarkable. The El Tor and classical biotypes gave similar results.