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Biomedical subjects

S Bengtsson

Publications and source records attributed to S Bengtsson.

At least 37 records · Page 2Linked to original sources

Antibiotic sensitivity of Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Branhamella catarrhalis isolated from upper respiratory tract infections in Sweden.

Isolates of Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Branhamella catarrhalis were collected from five laboratories in different geographical areas in Sweden. Nine hundred and fortyfour strains were tested by the agar dilution method for susceptibility to seven oral antibiotics: phenoximethylpenicillin, ampicillin, cefaclor, erythromycin, doxycycline, trimethoprim-sulfamethoxazole and chloramphenicol. The H. influenzae and B. catarrhalis strains were also tested for beta-lactamase production. Of the H. influenzae strains, 8% were beta-lactamase-producing, while 35% of B. catarrhalis strains produced beta-lactamase. The latter value is higher than has earlier been reported in Sweden. Five S. pneumoniae strains showed decreased sensitivity to penicillin, and 9.5% of the S. pneumoniae strains showed a decreased sensitivity to one or more of the seven antibiotics tested. The S. pyogenes strains were sensitive to all the antibiotics tested with the exception of 4% of the strains, which showed a decreased sensitivity to doxycycline.

Anti-Bacterial Agents↗

Oral pivampicillin and amoxycillin in newborn infants.

Ampicillin was administered intramuscularly and amoxycillin or pivampicillin orally to 14 fasting newborn infants, 6-13 days old, in a cross-over trial. The dose was 50 mg/kg twice daily. The mean peak plasma level of amoxycillin and pivampicillin was 58% (range 35-96%) and 48% (33-82%) of that noted after i.m. ampicillin, which gave a value of about 44 +/- 5 micrograms/ml (mean +/- SEM) in both groups. The area under the time-concentration curve was 75% (range 60-101%) of that of i.m. ampicillin for amoxycillin and 51% (20-76%) for pivampicillin (p less than 0.05). Both drugs, especially amoxycillin, should be useful for oral treatment of neonatal infections caused by susceptible microorganisms in infants who are not critically ill.

Administration, Oral↗

A dose response study with bacampicillin in uncomplicated gonorrhoea.

In a systematic study of dose-response relationship 883 patients with uncomplicated gonorrhoea were given single oral doses of 400, 800 or 1600 mg bacampicillin, with 1 g probenecid. A single dose of bacampicillin 800 mg plus probenecid was the minimum effective dose in patients with fully ampicillin-sensitive strains. In patients with gonococci showing reduced sensitivity to ampicillin, 1600 mg bacampicillin was required to reach a cure rate above 95%. Bacampicillin was well tolerated in all treatment groups. Side-effects were reported in 4.6% of the courses of treatment. The most frequent adverse reaction was loose stools (1.9%), which was noted more often after the 1600 mg dose but was considered to be of no or very little clinical importance.

Administration, Oral↗

Wound infections after surgery in a modern operating suite: clinical, bacteriological and epidemiological findings.

A prospective study of 2983 operations in general and orthopaedic surgery during 3 years performed in four operating theatres in a modern operating suite was carried out in order to evaluate the importance of airborne infection. Weekly nose-and-throat samples were taken from the surgical staff and pre-operative samples were taken from the nose, throat, skin and perineum of the patients. The air contamination was followed by using settle plates, which showed low mean counts of total bacteria of between 9 and 15 c.f.u./m(2)/min, with mean counts of Staph. aureus of between 0.03 and 0.06 c.f.u./m(2)/min. No correlation was found between the total number of bacteria and the incidence of post-operative infections or between the amount of Staph. aureus in the air and post-operative Staph. aureus infections. It was concluded that further increases in ventilation could, at best, only marginally affect the incidence of post-operative infection.The post-operative wound-infection rate was 9.0%. In various types of surgery, the infection rates varied from 5.3% in clean operations to 47.6% in dirty surgery. About one third of the infections were classified as moderate or severe.Adverse patient factors, such as immunodeficiency, steroid treatment, intensive care, etc., increased the rate to 15.0%; in ;normal' patients it was 3.8%.Among the bacteria isolated, gram-negative bacilli (31% of wounds), often together with other bacteria, and Staph. aureus (28%) predominated, but in 25% no specimens were taken.Of 76 post-operative Staph. aureus infections, 32 were caused by the patients' own strains, and of the remaining 44 infections, 22, or 8% of all infections, could be traced to strains present in the air and/or the respiratory tracts of staff during the operation.The length of pre-operative hospital stay had no influence on the carrier rate of Staph. aureus in patients. The incidence of post-operative wound infection was significantly higher in patients carrying Staph. aureus and was even higher if these bacteria were found on the skin.Patients with wound infections stayed, on an average, 15 days longer than patients without infections. In serious infections the increase in duration of stay was > 20 days. Although infections were commoner in older patients, the average additional hospital stay of infected patients did not increase with age. If the post-operative infections studied in a concurrent retrospective study are taken into account more than 12 000 bed-days were due to post-surgical wound infections in the period studied or, in other words, some 12 beds (corresponding to 5.5% of the total) were always occupied by infected patients.

Air Microbiology↗

Azidocillin levels in tracheobronchial secretions.

Concentrations of azidocillin in serum and tracheobronchial secretions were followed in 20 patients after an oral dose of 0.75 g of the drug. Serum concentrations were followed for 4 h and the concentration in tracheobronchial secretion was determined in samples taken through a fibreoptic bronchoscope 1--2 h after administration. The concentration in secretions varied between hardly measurable levels and 1.1 micrograms/ml. No correlation between levels in serum and tracheobronchial secretion was found. A slight tendency to higher secretion levels was found when the bronchoscopy showed signs of tracheobronchitis.

Administration, Oral↗

Bacterial contamination in a modern operating suite, 2. Effect of a zoning system on contamination of floors and other surfaces.

In this investigation the bacterial contamination of surfaces such as walls and floors in a modern operating suite, together with surfaces of lamps in the operating theatres, and the clogs worn by staff, was studied. Counts of colony-forming units were made on impression plates containing blood-agar with Tween 80 for total bacterial counts, Baird Parker medium with egg yolk and tellurite for Staphylococcus aureus and trypticase peptone agar with neomycin and polymyxin for Clostridium spp. The areas examined were divided into the patients' route to the operating theatre, the staff's route, and the central area containing the operating rooms, anaesthetic rooms, and exit and scrub-up areas. In the patients' route counts of total organisms ranged from about 10000 to 30000/m2; for Staph. aureus the range was from 70 to 540/m2. In the staff's route the highest count was about 70000/m2 in the dressing area, and the numbers of Staph. aureus were about the same as along the patients' route. In the inner zone the counts were somewhat lower for both total organisms and Staph. aureus. Total counts on the floor from all areas of the inner zone were significantly higher just before the second operation than before the first operation on the same day. The total and Staph. aureus counts on walls, floors and lamps were the same after clean operations as after operations classified as "contaminated" or "dirty".

Air Microbiology↗

Bacterial contamination in a modern operating suite. 3. Importance of floor contamination as a source of airborne bacteria.

The redispersal factor for bacteria-carrying particles from a contaminated floor was determined after mopping, blowing and walking activity. Walking gave the highest redispersal factor, 3.5 X 10(-3) m-1, which was three times higher than for blowing and 17 times higher than for mopping. The mean die-away rate for the bacteria-carrying particles used was 1.9/h without ventilation and 14.3/h with ventilation. It was calculated that in the operating rooms less than 15% of the bacteria found in the air were redispersed floor bacteria.

Air Microbiology↗

Bacterial contamination in a modern operating suite. 4. Bacterial contamination of clothes worn in the suite.

Clean clothes in the staff dressing rooms were heavily contaminated with bacteria, mainly Bacillus sp., but Staphylococcus aureus were found on 14% and Clostridium sp. on 10% of the garments examined. A comparison of the occurrence of Staph. aureus on shirts worn by staff in wards and operating departments showed ward shirts to be contaminated more heavily and with more strains. Examination of sterile gowns worn by surgeons showed that 70% were contaminated with Staph. aureus after operation. Of the strains isolated 31% were identical with those carried by the surgeon or by the patient operated on, but for the remainder no source could be found.

Bacillus↗

Inhibitors of neuronal monoamine uptake. 2. Selective inhibition of 5-hydroxytryptamine uptake by alpha-amino acid esters of phenethyl alcohols.

A series of alpha-amino acid esters of substituted phenethyl alcohols was prepared and tested as inhibitors of the neuronal reuptake of noradrenaline and 5-hydroxytryptamine. Some of the compounds are potent and very selective in blocking the 5-hydroxytryptamine uptake, as evidenced by biochemical data and behavioral tests. The most promising agent, alaproclate [2-(4-chlorophenyl)-1,1-dimethylethyl 2-aminopropanoate hydrochloride (I, IV)], was selected for further studies as a potential antidepressant agent. A discussion on structure--activity relationships (SAR) is given. In an attempt to explain the selective action on the mechanism of 5-hydroxytryptamine uptake by the new inhibitors, their structures are compared with those of the two neurotransmitters. From the tentative pharmacophore and conformations of transmitter (5-HT) and inhibitor (alaproclate) derived from SAR, a hypothetic carrier site for 5-HT uptake is deduced in terms of geometry and electronic properties.

Animals↗

Bacterial contamination in a modern operating suite. 1. Effect of ventilation on airborne bacteria and transfer of airborne particles.

The effect of ventilation on airborne contamination was studied in a new operating suite containing operating rooms with conventional ventilation (17-20 turnovers/h) and operating rooms with zonal ventilation, where the turnover in the central part of the room was approximately 80/h. The efficacy of the ventilation was first examined with gas tracer experiments and found satisfactory. Experiments using potassium iodide particles showed the transfer between adjacent rooms in the suite to be less than 10(-3)% with closed doors and from 1% to 2.5 x 10(-2)% when the doors were opened once a minute. The transfer between two adjacent operating rooms was calculated to be approximately 10(-4)%. There is thus little risk of spread of airborne infection between operating rooms.Experiments with potassium iodide particles showed that in operating rooms with zonal ventilation the particle concentration in the centre of the room was about one-tenth that in the periphery; in conventionally ventilated operating rooms the concentration was about one-half. With bacteria-carrying particles generated by human activity the concentration in the centre of operating rooms with zonal ventilation was about half that in the periphery both during experimental activity and operations; in conventionally ventilated operating rooms it was about equal in both cases. Bacterial counts at the periphery were found to be lower in rooms with zonal ventilation ( approximately 50 c.f.u./m(3)) than in conventionally ventilated ( approximately 70 c.f.u./m(3)).

Air Microbiology↗

Airborne contamination and postoperative infection after total hip replacement.

The results of 163 hip replacements at the Uppsala University Hospital are presented. Deep infection occurred in ten cases and was caused by Staphylococcus aureus in four early or intermediate infections and by anaerobes in four late infections. The remaining two infections (both of which were late) were probably associated with Staphylococcus albus--in one case possibly also with alpha streptococci. Two superficial infections not affecting the operative result were caused by Staphylococcus aureus and betahaemolytic streptococci. The results of environmental analyses of staphylococci and the total number of bacteria in the air during 77 operations did not indicate that airborne infection is a major cause of postoperative infections--there was no difference between the number of bacteria found in the air during operations after which infection occurred and uninfected operations, and the use of special zonal ventilation with high rates of air exchange in the operating area had no effect on the infection frequency.

Aged↗

Penicillinase production in community strains of staphylococcus aureus.

A survey of penicillinase production in 406 strains of Staphylococcus aureus isolated from wounds in the County of Uppsala in 1975 showed that 76% of strains from inpatients produced penicillinase compared to 69% of the outpatient strains. The frequency of penicillinase production in Staph. aureus strains from surgical staff was 59%. 51% of strains from school children and 38% of strains from healthy adults produced penicillinase. The conclusions are that ordinary penicillinase-sensitive penicillin should not be used for treating infections in outpatients unless the isolated aureus strain has been shown to be penicillinase-negative.

Adult↗

A retrospective study of the occurrence of beta-haemolytic streptococci of various Lancefield groups in routine cultures from the County of Uppsala.

During the months October to December of the years 1971-1974 the incidence of beta-haemolytic streptococci of the Lancefield groups, A, B, C and G from patients in the County of Uppsala was studied. The proportion of culture positive patients increased during the period studied from 7.2% to 13.7%. The increase was not only due to group A. In cultures from the respiratory tract the finding of group A streptococci increased from 4.1% to 10.7% and group C from 0.1% to 1.6%, while group B and G streptococci remained constant. In cultures from wound infections the percentage of patients culture positive for group A streptococci increased from 6.2% to 8.7%, group B from 0.8% to 1.9%, and group G from 0.5% to 0.9%, while group C remained constant. During the same months of the years 1972 to 1974 the frequency of sera with an antistreptolysin O titre of more than 1 000 U/ml increased from 0.6% t0 2.3% in the same region. A clinical study of scarlet fever and pharyngotonsillitis at the Department of Infectious Diseases showed a similar trend concerning group A streptococcal infections. These results stress the great importance of group A beta-haemolytic streptocci in human infections and indicate that the recent interest in non-group A infections should be continued.

Bacteriological Techniques↗

Pathophysiology in the acute afferent loop syndrome. A study in rats.

The afferent loop syndrome, i.e. occlusion of an afferent intestinal loop after a Billroth II partial gastrectomy, was induced in rats. After various time intervals the animals were killed and the haematocrit and serum osmolality were determined. The content of the occluded loop was analysed with respect to volume, bacterial flora and osmolality. In some cases a sample of the content was incubated at 37 degrees C and the osmolality determined at regular intervals. Groups of animals were studied in this way after 30 min or 1, 4, 8 or 12 h of occlusion. The haematocrit rose with time after the occlusion. The osmolality of the plasma and of the content of the occluded loop did not increase. The volume of fluid in the occluded loop increased continuously with time--from an average of 0.5 ml in the control cases to 6.1 ml after 12 h of occlusion. Experiments in vitro showed that the initial osmolality of the content of the loop was 300 mOsm. After incubation of the samples this increased by 43 to 146 percent. The bacterial content of the loop, including Clostridium perfringens, increased significantly. The results indicate that a marked breakdown of substances takes place in such an occluded intestinal loop, which increases the osmolality. As a result fluid is immediately attracted to the loop to keep the osmolality constant. A combination of this fluid increase due to osmosis and contractions of the intestinal wall leads to a pressure in the occluded loop which considerably exceeds the pressure in the common bile duct due to secretions from the pancreas and liver.

Acute Disease↗