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Biomedical subjects

O V Renkonen

Publications and source records attributed to O V Renkonen.

At least 19 recordsLinked to original sources
PubMed1992

Evaluation of the E test in testing susceptibility of Pseudomonas aeruginosa to tobramycin.

The E test, a new technique for measuring MICs of antimicrobial agents with the ease of disc diffusion tests, was evaluated in testing the susceptibility of 94 clinical isolates of Pseudomonas aeruginosa to tobramycin. The use of the E test was found acceptable; 93% of the MIC results were within one log2 dilution step and 100% were within two log2 dilution steps when the MICs obtained by the E test were compared to those obtained by the conventional agar dilution method. When the E test was compared to the broth microdilution method the corresponding figures were 84% and 100%, respectively.

Colony Count, Microbial↗
PubMed1992

Pneumococcal bacteraemia during a recent decade.

We retrospectively reviewed 159 episodes of bacteraemic pneumococcal infection in 157 adult patients at the Helsinki University Central Hospital during two periods between 1976 and 1979 and 1986 and 1989. We looked especially at changes in underlying diseases and prognostic factors. The overall case fatality rate was 21% and there was a small diminishing trend in that rate from 28% (16/58) in the late 1970s to 17% (17/101) in the late 1980s. The patients who died in the late 1980s were younger than those who died in the earlier period. The most common underlying factors were alcohol abuse, cardiovascular diseases and chronic obstructive pulmonary diseases. Old age was neither a predisposing factor nor did it predict the outcome. No significant changes in underlying diseases or prognostic factors were noted during the two periods studied except a small decrease in connective tissue diseases as underlying conditions. The factors related to increased fatality included hepatic cirrhosis, a combination of pneumonia and meningitis, complications such as shock, respiratory insufficiency, central nervous system disorders and circulatory acidosis, and laboratory findings such as thrombocytopenia, absence of leucocytosis and increased amounts of serum creatinine, aspartate aminotransferase and alanine aminotransferase on admission to the hospital. Previous splenectomy and malignant diseases were not associated with higher mortality. The thrombocytopenia at the time of positive blood culture and the circulatory acidosis as a complication seemed to be independently the most useful predictive factors for a fatal outcome using multivariate logistical regression analysis after adjustment to classic risk factors.

Adolescent↗
PubMed1992

Clinical presentation and outcome of listeriosis in patients with and without immunosuppressive therapy.

Seventy-four cases of systemic listeriosis occurring from 1971 to 1989 in the greater Helsinki area in Finland are reviewed with a special interest in the effect of preceding immunosuppressive therapy on the clinical presentation. Of these patients, 66% had an underlying disease, most commonly malignancy, diabetes mellitus, or renal transplantation, and 43% had received immunosuppressive therapy within 1 week before onset of listeriosis. Bacteremia and central nervous system infections (both in 43% of cases) were the most common clinical entities. The percentage of patients with meningitis was not greater among immunosuppressed patients (13/32, 41%) than among patients with underlying diseases not treated with immunosuppressive agents (9/16, 56%) or among previously healthy nonpregnant hosts (7/11, 64%). Immunosuppressed patients did not die more frequently than did those with underlying diseases not treated with immunosuppressive therapy (case fatality rate, 29% vs. 38%, respectively). However, all previously healthy non-neonatal patients survived, whereas 32% (15/47) of those with any kind of underlying disease succumbed.

Adolescent↗
PubMed1992

Role of metronidazole resistance in therapy of Helicobacter pylori infections.

Susceptibility to metronidazole was determined by disk diffusion tests for 559 strains of Helicobacter pylori isolated from patients. The overall metronidazole resistance was 26%. In males metronidazole-resistant strains made 18% of all H. pylori strains, and in females the corresponding figure was 40% (P less than 0.001). MICs of metronidazole were determined for H. pylori strains from 86 patients undertaking triple therapy, i.e., treatment with colloidal bismuth subcitrate, amoxicillin, and metronidazole. Of the nonresponders who remained culture positive despite the therapy, 69% had strains with metronidazole MICs of greater than or equal to 32 micrograms/ml before the therapy, and all nonresponders had metronidazole-resistant strains after the therapy. Metronidazole resistance was, however, also found in 27% of responders before therapy. To find whether the MICs of metronidazole for H. pylori strains remained constant for longer periods, consecutive isolates sampled several years apart from the same patients were tested in parallel and no changes in the MICs were found. H. pylori was successfully eradicated by the triple therapy from 91% of patients with metronidazole-susceptible pretreatment strains and from 63% of patients with metronidazole-resistant strains before the therapy (P less than 0.01). Although resistance to metronidazole has a significant role in treatment failures in H. pylori infections, high eradication rates can be achieved with the use of the present triple therapy even in populations with a high overall metronidazole resistance rate.

Adult↗
PubMed1992

Pharmacokinetics and transplacental passage of imipenem during pregnancy.

Imipenem pharmacokinetics were studied in early pregnancy (n = 7; length of gestation, 8.6 +/- 1.5 weeks, mean +/- standard deviation), in late pregnancy (n = 7; length of gestation, 38.7 +/- 1.4 weeks), and in the nonpregnant state (n = 6). A single dose of 500 mg of imipenem-cilastatin (1:1) was administered as a 20-min infusion. Multiple plasma and urine samples, as well as specimens of umbilical plasma and amniotic fluid from the pregnant subjects, were collected at frequent intervals for 8 h. Imipenem concentrations were assayed by specific microbiologic assay. The mean peak concentrations in plasma were 14.7 +/- 4.9, 14.9 +/- 5.2, and 43 +/- 28.3 micrograms/ml in early pregnancy, late pregnancy, and the nonpregnant state, respectively. The volumes of distribution were significantly larger during early pregnancy (0.98 +/- 0.45 liter/kg of body weight, P < 0.005) and late pregnancy (0.59 +/- 0.19 liter/kg, P < 0.05) than in the nonpregnant state (0.33 +/- 0.10 liter/kg), and total clearances from plasma were faster in early pregnancy (12.7 +/- 7.8 ml min-1 kg-1, P < 0.05) and late pregnancy (10.7 +/- 4.6 ml min-1 kg-1, P < 0.05) than in the nonpregnant state (5.77 +/- 1.19 ml min-1 kg-1). The mean concentrations in amniotic fluid were 0.07 +/- 0.01 and 0.72 +/- 0.85 micrograms/ml in early and late pregnancy. The mean umbilical venous and arterial drug concentrations were 1.72 +/- 1.22 and 1.64 +/- 1.22 micrograms/ml. The feto-maternal ratio at the time of cesarean section was 0.33 +/- 0.12. These results indicate that an adjustment of doses of imipenem may be required when treating pregnant women because of considerable changes in imipenem pharmacokinetics during pregnancy.

Adolescent↗
PubMed1992

Pharmacokinetics of single-dose oral ciprofloxacin in infants and small children.

The pharmacokinetics of orally administered ciprofloxacin (CIP) was studied in seven infants aged 5 to 14 weeks and nine children aged 1 to 5 years, most of whom were Salmonella carriers. In each case, 15 mg of CIP per kg of body weight was given with water on an empty stomach, and timed serum samples were taken during the following 12 h. The elimination half-life of CIP was significantly (P less than 0.001) longer in the infants (2.73 +/- 0.28 h; mean +/- standard deviation) than it was in the children (1.28 +/- 0.52 h). The area under the serum CIP concentration-time curve (AUC) from time zero to infinity was 16.1 +/- 7.4 mg.h.liter-1 among the infants and 5.3 +/- 3.3 mg.h.liter-1 in the children (P less than 0.01). No significant differences in the maximum concentration in serum, time to maximum concentration in serum, or absorption half-life were observed between the two groups. In contrast, the mean residence time was twofold longer in the infants (4.6 h) than it was in the children (2.4 h; P less than 0.001). The findings suggest that elimination of CIP is particularly rapid in children who just have passed infancy; they may require doses at shorter time intervals than those required by infants or older children or adults. In general, an oral dose of 10 to 15 mg of CIP per kg three times daily seems appropriate for children aged 1 to 5 years.

Administration, Oral↗
PubMed1992

Bacterial vaginosis in early pregnancy and pregnancy outcome.

OBJECTIVE: We assessed the association between bacterial vaginosis in early pregnancy and adverse pregnancy outcome. METHODS: Vaginal swabs for bacterial culture, Gram stain, and Papanicolaou stain were taken at the first prenatal visit between 8-17 weeks' gestation in 790 healthy nulliparous women. RESULTS: Culture-proven bacterial vaginosis was detected in 169 of 790 women (21.4%), 167 (98.8%) of whom could also be identified by Gram stain. Papanicolaou smears were available from 299 women, among whom 101 had bacterial vaginosis on culture; of these 101, 78 (77.2%) could be detected by Papanicolaou stain. Of the 751 women whose clinical follow-up was completed, 42 had been treated for preterm uterine contractions (preterm labor), but only 17 delivered between 20-36 weeks' gestation (preterm birth). Premature rupture of membranes (PROM) occurred more than 6 hours before delivery in 80 cases (nine preterm and 71 term). Bacterial vaginosis in early pregnancy predicted preterm labor, preterm birth, or preterm PROM with a sensitivity of 41-67%, specificity of 79%, and negative predictive value of 96-99%, but the positive predictive value was low at 4-11%. However, bacterial vaginosis was associated with a 2.6-fold risk (95% confidence interval [CI] 1.3-4.9) for preterm labor, a 6.9-fold risk (95% CI 2.5-18.8) for preterm birth, and a 7.3-fold risk (95% CI 1.8-29.4) for preterm PROM. CONCLUSIONS: Bacterial vaginosis in early pregnancy can be detected reliably by Gram stain and, in most cases, by Papanicolaou smear. Although bacterial vaginosis is associated with preterm labor, preterm birth, and preterm PROM, the clinical usefulness of its assessment is limited because of the high rate of false-positive findings.

Adult↗
PubMed1991

Emergence of fluoroquinolone resistance in Campylobacter jejuni and Campylobacter coli in subjects from Finland.

The in vitro susceptibilities of 102 human campylobacter strains isolated between 1978 and 1980 and 100 strains isolated in 1990 to ciprofloxacin, norfloxacin, erythromycin, gentamicin, and doxycycline were examined. The biotypes and heat-stable serotypes of the strains as well as antimicrobial treatments and travel history of the campylobacter-positive patients were also studied. The results indicated that susceptibility to erythromycin, gentamicin, and doxycycline has remained the same during the past 10 years. No gentamicin-resistant strains were found. Resistance to erythromycin was 3% in both groups of strains. However, the number of norfloxacin-resistant strains increased from 4 to 11% in the follow-up period, and ciprofloxacin-resistant strains, which had not occurred 10 years ago, composed 9% of the strains isolated in 1990. Thus, the increase of fluoroquinolone resistance in Campylobacter jejuni and Campylobacter coli has been significant in Finland in the past 10 years.

4-Quinolones↗
PubMed1991

Antibiotic concentrations in liquor compared to the minimal inhibitory concentrations of isolates in paediatric bacterial meningitis. The Finnish Study Group.

The susceptibilities of 171 bacteria which caused meningitis in 200 children were tested for their susceptibility as minimal inhibitory concentrations (MICs) for the antibiotics used in therapy. These antibiotics were chloramphenicol, ampicillin, cefotaxime and ceftriaxone. The MICs were compared to the minimal concentrations of the drugs seen in the cerebrospinal fluid (CSF) samples. The minimal bacteriostatic capacity (lowest concentration in CSF/MIC) of both cephalosporins was superior to that of chloramphenicol and ampicillin. The correlation of the finding with the speed of liquor sterilization in the treatment groups is discussed.

Adolescent↗
PubMed1990

The emergence and mechanisms of trimethoprim resistance in Escherichia coli isolated from outpatients in Finland.

Trimethoprim (TMP), either alone or in combination with sulphonamides, is commonly used for treating urinary tract infections. In Finland, TMP alone has been in clinical use since 1973. TMP resistance in the major outpatient urinary tract pathogen, Escherichia coli, increased during 1978-1988 from 5% to 16% in the Turku area, during 1980-1988 from 3% to 19% in the Helsinki area and also during 1980-1988 from 3% to 14% in the Rovaniemi area. The majority (91%) of TMP-resistant strains were highly-resistant to TMP (MIC greater than or equal to 1024 mg/l). The most common (57%) TMP resistance gene, detected by DNA hybridization, was the type I dihydrofolate (DHFR) gene. The type II DHFR genes were found in less than 3% of the strains studied. No positive hybridizations were detected with the type III DHFR probe, and only a few positive hybridizations were found with the type V DHFR probe. Forty percent of the isolates did not hybridize with any of the DHFR probes used, suggesting additional unknown resistance mechanisms responsible for the high-level TMP resistance. These unknown TMP resistance mechanisms, together with the type I DHFR-mediated resistance, were responsible for the increase of TMP resistance among the E. coli strains studied.

Escherichia coli↗
PubMed1990

On the proteolytic activity of contact lenses and bacteria.

Contact lens wear (CLW) has been shown to cause an elevation in tear fluid (TF) plasmin levels. This study investigated whether the proteolytic activity assayed by a caseinolytic technique was also bound by CLs and whether certain bacterial species contribute to the production of plasmin. CLs worn by patients with corneal disease showed proteolytic activity in five out of nine cases when examined on casein agar. Histological and electron microscopic examination of the lenses revealed bacterial adherence and growth on both surfaces of the CLs. Strains of Staph. epidermidis, Staph. aureus, Pseudomonas aeruginosa and Branhamella catarrhalis, isolated from eyes with external infections, were cultured on a modified milk casein agar and examined for their proteolytic activity. Neither cultures of Branhamella catarrhalis nor Staph. aureus showed proteolytic activity when examined by direct caseinolytic assay. The proteolytic activity shown by Staph. epidermidis or Pseudomonas aeruginosa was not affected by a proteinase inhibitor aprotinin. However, when exogenous plasminogen was added into the casein agar, Staph. aureus was shown to produce caseinolytic activity. This activity was interpreted to be due to plasminogen activator (PA) activity. It was inhibited by aprotinin. Examination of culture fluids of the bacterial species mentioned above did not show caseinolytic activity. Culture fluid of Staph. aureus contained PA activity. The present study confirms the ability of certain bacterial species to adhere to CLs. Moreover, proteases such as plasmin and bacterial enzymes are present in TF during CL wear and may even adhere to the surface of CLs. Hence, bacterial growth probably contributes to the production of proteases on the ocular surface during CL wear.

Adolescent↗
PubMed1990

A randomised comparison of ceftazidime and piperacillin, both in combination with flucloxacillin for treatment of febrile episodes in neutropenic children. Finnish Three-Centre Study.

111 febrile episodes in 98 neutropenic children were randomly treated with either ceftazidime (CAZ) 150 mg/kg/day or with piperacillin (PIP) 200 mg/kg/day, both combined with flucloxacillin (FLUC) 50 mg/kg/day. A total of 37/47 (79%) eligible episodes in the CAZ group and 41/53 (77%) in the PIP group were cured without needing to stop the initial therapy. The success without modification of the treatment in the verified septicaemias in the CAZ group was 8/18 (44%) and in the PIP group 5/18 (28%). Of the bacteriologically documented infections, 13/24 (54%) in the CAZ group and 11/24 (46%) in the PIP group were cured without modification of the therapy. Similarly, 17/31 (55%) of all the isolated bacteria in the CAZ group and 14/33 (42%) in the PIP group were eradicated with the initial therapy. Overall there were 13 deaths of which 4 in the CAZ group and 5 in the PIP group occurred during the infection. An increasing granulocyte count exceeding 0.25 x 10(9)/l at the end of the therapy was a good prognostic sign for the outcome of the infection. This study indicates that CAZ is as effective as PIP in the treatment of infections in neutropenic children.

Adolescent↗
PubMed1989

Randomised comparison of chloramphenicol, ampicillin, cefotaxime, and ceftriaxone for childhood bacterial meningitis. Finnish Study Group.

In a multicentre study, 220 consecutive cases of bacterial meningitis in children older than 3 months were randomised to treatment with chloramphenicol, ampicillin (initially with chloramphenicol), cefotaxime, or ceftriaxone. The drugs were given in four equal daily doses for 7 days, except ceftriaxone which was given only once daily. 200 cases could be assessed; the causative organisms were Haemophilus influenzae type b (Hib) in 146; meningococci (Mnc) in 32; pneumococci (Pnc) in 13; and other or unknown in 9. In patients with Hib meningitis, sterilisation of the cerebrospinal fluid occurred most rapidly with ceftriaxone. Otherwise, in terms of overall clinical recovery, normalisation of laboratory indices, clinically significant adverse reactions, toxic effects, sequelae, and mortality rate, the treatment groups were very similar. However, there were 4 bacteriological failures, all in the chloramphenicol group. Also, the treatment was extended or changed in more cases in the chloramphenicol group than in the other groups. Chloramphenicol was thus inferior to the other three antimicrobials. Ampicillin is a good and cheap alternative, but there are difficulties with resistance. Easy administration tempts the use of ceftriaxone rather than cefotaxime but it causes diarrhoea. A 7-day course of ampicillin, cefotaxime, or ceftriaxone is sufficient in Hib, Mnc, or Pnc meningitis.

Adolescent↗
PubMed1989

Prospective study of the etiology of diarrhea in adult outpatients and inpatients.

A prospective study of the etiology of diarrhea in 253 adult outpatients and inpatients was conducted in Helsinki in 1985-86. The outpatients constituted 84.6% of all patients studied. A broad panel of diagnostic techniques was applied, including detection of bacteria and parasites in the feces and determination of the serologic responses to campylobacter, salmonella, Yersinia enterocolitica, and several viruses. Pathogens were identified for 28.5% of the patients. The commonest findings were Campylobacter jejuni/coli in 13.0% and Salmonella species in 7.1% of the patients. Mixed infections of several pathogens were found in 16 patients.

Adult↗
PubMed1989

Effect of erythromycin acistrate and erythromycin stearate on human colonic microflora.

The effects of erythromycin acistrate (2'-acetyl erythromycin stearate), a new erythromycin derivative, and erythromycin stearate on the faecal microflora were compared in a randomized cross-over study. 12 healthy volunteers were given either drug 500 mg t.i.d. for 1 week. Their faeces were studied before, immediately after, and 1 week after the drug administration period. After a wash-out period of 4 weeks, the drugs were interchanged. Both erythromycin acistrate and erythromycin stearate induced changes in the normal colonic microflora to about the same extent. The most marked effect was the suppression of gram-negative anaerobic and aerobic rods. Clostridium difficile appeared in 1 subject on both drugs. Also the counts of aerobic gram-positive cocci were altered; enterococci increased in number. An increased resistance to erythromycin was noted among staphylococci and enterococci after both drugs.

Adolescent↗