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Biomedical subjects

A Hambraeus

Publications and source records attributed to A Hambraeus.

At least 37 records · Page 2Linked to original sources
PubMed1992

The role of white cells in the transmission of Yersinia enterocolitica in blood components.

The mechanism for the transmission of Yersinia enterocolitica in blood components has been studied experimentally. One hypothesis is that, during a Yersinia infection in the blood donor, bacteria are phagocytosed by white cells (WBCs), but are not killed. After collection of blood from such a donor and component production, the bacteria are present in WBCs for some time, during which the unit appears sterile. Later, when the WBCs disintegrate, the bacteria are released and multiply in the unit. Aliquots of whole blood and buffy coat were inoculated with 100 colony-forming units (CFU) per mL of a Y. enterocolitica strain of type O:3 and left at room temperature for 5 hours. Some aliquots were then WBC-reduced by filtration, while others retained their WBC contents. All aliquots were kept at 4 degrees C for 6 weeks. Meat extract broth culture medium was used as a control. Growth in the range of 2000 CFU per mL was obtained in the broth control by 24 hours, whereas the whole blood and buffy coat units appeared sterile for the first days of storage. After 1 week, a trace of bacteria and, after 4 weeks, massive growth were found in the WBC-containing units but not in the WBC-reduced units. The likely explanation is that the bacteria had been phagocytosed by the WBCs and were thereby hidden and not available for bacterial culture during the first phase of storage. When the WBCs spontaneously disintegrated, bacteria were released and multiplied in the blood units.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Preservation↗
PubMed1991

The relative importance of routes and sources of wound contamination during general surgery. I. Non-airborne.

A study was undertaken to determine the relative importance of some sources, routes of transmission, and measures to prevent bacteria entering the wound during biliary tract surgery. When bacteria were growing in the bile they accounted for the majority (greater than 99%) of the bacteria found in the wound. However, when the bile was sterile the skin bacteria at the incision site were found to make a substantial contribution to the wound flora. The difference in the total wound contamination between a patient who had practically no skin bacteria and one who had an average amount was in the region of 17-fold. No transfer of skin bacteria from the surgical team through perforated gloves or by direct contact from the surface of operating gowns was demonstrated. Ten of the patients studied had septic wounds. Five of these were infected by bacteria from the bile.

Anti-Bacterial Agents↗
PubMed1991

Multiply antibiotic-resistant Staphylococcus epidermidis in patients, staff and environment--a one-week survey in a bone marrow transplant unit.

The distribution of Staphylococcus epidermidis resistant to ciprofloxacin and/or gentamicin was studied in an isolation unit for patients undergoing bone marrow transplantation. During 1 week all such strains colonizing patients or staff members or found on the clothes of staff or in the air were investigated. Antibiograms and plasmid profiles were used for epidemiological typing. Thirty-one different antibiograms were found. A few strains were widely spread and dominated quantitatively. Staff colonization was 23%, but contamination of their clothes was 82%. Two strains which colonized three of the patients were widely spread in the air. They were found in the corridor and in every patient room, even where the patient was not colonized. The main source of the environmental contamination seems to have been patients. Possible routes of infection were direct airborne transmission as well as passive transfer via staff.

Bone Marrow Transplantation↗
PubMed1991

White cells protect donor blood against bacterial contamination.

The possible beneficial role of white cells (WBCs) in donor blood has been investigated with respect to their capacity to remove bacteria. Preparations of buffy coat and whole blood, containing as well as reduced of WBCs, were inoculated with Staphylococcus epidermidis, S. aureus, Escherichia coli, Pseudomonas aeruginosa, and Propionibacterium species. Upon storage at room temperature, the presence of WBCs resulted in a reduction of the bacterial content. Units inoculated with S. epidermidis and E. coli were completely cleared of bacteria within 5 to 24 hours. On the other hand, S. aureus, after an initial reduction in number, started to multiply. In WBC-reduced units, the initial bacterial content remained unchanged for 5 hours, but the bacteria then exhibited vigorous growth within 48 hours in buffy coat and slower growth in whole blood. Propionibacterium sp. did not grow with or without WBCs. P. aeruginosa did not grow in buffy coat but showed a growth pattern similar to that of S. aureus in whole blood. The presence of WBCs in the donor blood during the first hours after collection thus seems to rid the blood of at least some species of bacteria. These results indicate that it would be favorable not to perform WBC reduction during blood collection and that several hours of contact can be needed to obtain sterility.

Blood↗
PubMed1991

Screening tests for the detection of methicillin resistance in Staphylococcus epidermidis.

Methods to detect resistance to methicillin in Staphylococcus epidermidis were studied in order to find a rapid screening test suitable for routine use. One hundred and forty-nine clinical isolates, 16 isolates from skin of healthy people and two reference strains were studied. Hypersecretion of beta-lactamase as a cause of methicillin resistance was eliminated in the strains studied. Tube and microtitre breakpoint, agar breakpoint and disc diffusion methods were compared. The breakpoint for methicillin resistance used was 16 mg/L in broth and 10 mg/L in agar. The discs used contained 1 and 5 micrograms oxacillin and 5 and 10 micrograms methicillin. Turbidimetric measurements in broth during incubation were carried out using the Bioscreen analysing system. The skin strains were founf to be susceptible in all tests. Using an inoculum of 10(7) cfu/mL 111/149 clinical isolates were classified as resistant after incubation for 24 h at 35 degrees C using the tube and microtitre breakpoint tests, incubation for 72 h did not increase this rate. When an inoculum of 10(5) cfu/mL was used 73% of these strains were identified within 24 h and all within 72 h with the tube breakpoint test. Using the microtitre breakpoint test, with an inoculum of 10(5) cfu/mL or lower, all resistant strains were not detected within 48 h. All agar breakpoint tests required 48 h incubation for reliable results. Only the 1 microgram oxacillin disc always separated strains found to be resistant or susceptible in the tube breakpoint test. The zone of inhibition was clearly readable after 16 h of incubation at 35 degrees C.

Culture Media↗
PubMed1991

Spread of Klebsiella in a neonatal ward.

The colonization of infants with Klebsiella pneumoniae was prospectively studied. Samples were taken from nose, throat, umbilicus and rectum on the day of arrival and thereafter once a week. Phage typing was performed the first time K. pneumoniae was found at any of these sites. Settle plates were exposed in the incubators and in the patient rooms 5 h/day. The study lasted for 32 weeks. The first 15 weeks was a control period with no information to the staff, the following 4 weeks was a period of intervention and education and the last 13 weeks was a second control period. In all, 603 infants were investigated. The number of infants nursed per week and severity of their disease was comparable in the 3 periods. The colonization rates were 65, 34 and 58%, respectively. The acquisition of new strains was 1.4 per infant in the first and last periods, but only 0.4 in the period of intervention. Thus, colonization rates decreased only during the period of continuous education in hygiene.

Air Microbiology↗
PubMed1990

Skin sampling-validation of a pad method and comparison with commonly used methods.

Two types of pad were tested for sampling bacteria from the skin. One pad was made of 85% viscose and a 15% mixture of polyester and polyamide fibres, the other was made of polyvinyl-alcohol foam. The efficiency was calculated using double samples and 8 consecutive samples. The two pads were equally efficient and more efficient when moist. Their efficiency was compared with that of the bud swab, the Rodac plate and the scrub cylinder method. Using the double sample method for calculation, the scrub cylinder method and the pads were equally efficient, around 50%. As calculated from consecutive samples the efficiency of the pads was about 45%, the efficiency of the cylinder scrub method 29%, and that of the bud swab and Rodac plate 16% and 5% respectively. The low efficiency of the Rodac plate may be partly explained by the fact that microcolonies and not bacterial cells are sampled with this method.

Bacteria↗
PubMed1990

An investigation of occlusive polyester surgical clothing.

The bacterial dispersion rate of people wearing operating room clothing made from several types of polyester fabric was compared to conventional cotton clothing, total-body exhaust gowns and disposable clothing. Airborne bacteria were measured in a chamber, three ultra-clean air operating rooms and a conventionally ventilated operating room. The polyester clothing was demonstrated to be much superior to conventional cotton clothing and at least as good as the total-body exhaust gowns and disposable clothing.

Air Microbiology↗
PubMed1990

Biliary tract surgery: a bacteriologic and epidemiologic study.

The sources and routes of postoperative wound infections were prospectively studied in 440 patients undergoing biliary tract surgery. The overall infection rate was 7.3%. Specimens for culture were taken peroperatively from bile, liver bed and subcutaneous fat in 402 patients and also from skin in 64. Of the 126 patients with positive bile culture (31%), all but one had bacteria in the other intraoperative cultures, with high counts of bile bacteria in liver bed and transfer of such bacteria to subcutaneous fat in 81.2%. The wound infection rate in this group was 12.8%. Of the 276 patients with sterile bile, more than 90% had bacteria in the other intraoperative cultures. The degree of contamination was low, with dominance of typical skin bacteria, and the group wound infection rate was 3.2%. In 19 postoperative wound infections intraoperative cultures were available for comparison. Eleven of these infections were classified as endogenous, six as exogenous and two as of uncertain origin. S. aureus was uncommon in bile and intraoperative wound cultures, but was almost as common as E. coli in the etiology of postoperative wound infections, indicating high pathogenicity.

Adult↗
PubMed1989

Methicillin-resistant Staphylococcus aureus in two burn units: clinical significance and epidemiological control.

Routine isolation adequately controlled MRSA strains in two burns units with a restrictive antibiotic policy. Ventilation control and more rigorous change of clothing offered no further advantage. No carriers among staff were found, but some suffered minor skin lesions that were the source of further MRSA spread. Spread of MRSA from the unit to other parts of the hospital was prevented by early identification of colonized patients and by restricting patient and staff movement.

Burn Units↗
PubMed1984

Influence of ethanol with and without chlorhexidine on the bacterial colonization of the umbilicus of newborn infants.

The effect of daily treatments with 70% ethanol and with 0.5% chlorhexidine in 70% ethanol, respectively, on navel colonization in newborns has been studied in 624 infants in two maternity wards during a four-month period. Staphylococcus aureus, group B and G streptococci, E. coli and anaerobes were significantly less often isolated from newborns whose umbilical cord was treated with chlorhexidine in ethanol than from those treated with ethanol only. Staphylococcus epidermidis and enterococci, on the other hand, were significantly more often isolated from the chlorhexidine-ethanol than from the ethanol group. More infants without colonization of the umbilicus on their fourth day of life were found in the chlorhexidine in ethanol than in the ethanol group. The infants in the ethanol group were colonized with significantly more bacterial species than the infants in the other group. Signs of dissemination of group B and group G streptococci between babies were seen more often in the group of infants treated with ethanol than in the one treated with chlorhexidine-ethanol.

Chlorhexidine↗
PubMed1983

The influence of the total body exhaust suit on air and wound contamination in elective hip-operations.

An evaluation of the effect of total body exhaust clothing on air and wound contamination was made in an operating theatre with a zonal ventilation system. Sixty-four patients who underwent total hip replacement using the Charnley-Müller prosthesis were studied. The members of the surgical team wore total body exhaust suits (TBE-suit), or conventional theatre clothing (C-clothing) at alternate operations. Nearly half of the patients in each group were given prophylactic antibiotics. Both the mean and median values of airborne bacteria in the operating theatre were significantly lower during operations with TBE-suits than with conventional theatre clothing. The lowest number, 4.0 cfu/m3, was found at the site of the operation wound. Cultures from adhesive drapes showed growth in 46 per cent of the C-group and in 43 per cent of the TBE-group samples. Wound washouts showed growth in 43 per cent of the C-group and in 10 per cent of the TBE-group samples. Staphylococcus epidermidis was the most frequently isolated bacteria both from adhesive drapes and from wound washouts. The rate of superficial infections was slightly higher when C-clothing was used. Deep infections were found in one patient in the TBE-group and in two patients in the C-group. None of the infected patients had received prophylactic antibiotics.

Adult↗