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Biomedical subjects

A R Ronald

Publications and source records attributed to A R Ronald.

At least 145 records · Page 8Linked to original sources
PubMed1979

Prophylaxis of recurrent urinary tract infection in female patients. Efficacy of low-dose, thrice-weekly therapy with trimethoprim-sulfamethoxazole.

Thirty-two women with recurrent urinary tract infections were treated after eradication of existing infections with a mixture of 40 mg of trimethoprim and 200 mg of sulfamethoxazole thrice weekly at bedtime for six months. Six preadolescents received one half this dose. During 21.3 cumulative patient-years of prophylaxis, one infection due to Streptococcus faecalis and one due to a sulfamthoxazole-and trimethoprim-sensitive Escherichia coli occurred--an infection incidence of 0.1 per patient-year. During prophylaxis, 61 of 72 periurethral cultures and 24 of 51 anal canal cultures failed to yield Enterobacteriaceae. One patient had transient colonization with a trimethoprim-resistant E coli during prophylaxis. Twenty-one patients had recurrent infection within six months of discontinuation of prophylaxis, with a mean time to recurrence of 2.6 months. One infection recurred 26 weeks following prophylaxis with a Proteus mirabilis. Thrice-weekly trimethoprim-sulfamethoxazole therapy was effective for prophylaxis of recurrent urinary tract infections and did not predispose to colonization or infection with trimethoprim-resistant Enterobacteriaceae.

Adolescent↗
PubMed1979

Clinical efficacy and toxicity of netilmicin in the treatment of gram-negative infections.

Netilmicin, a new semisynthetic aminoglycoside antibiotic, was used to treat 41 infections in 38 patients. The outcome of four infections could not be evaluated: two patients received inadequate therapy and two did not have gram-negative infections. Clinical improvement occurred in 36 (97%) of the 37 gram-negative infections, and bacteriologic cure occurred in 30 (86%) of the 35 evaluable infections. Therapeutic serum concentrations of netilmicin were readily achieved by both intramuscular and intravenous routes. Reversible ototoxic effects occurred in 1 (3%) of 35 courses of therapy evaluated, reversible nephrotoxic effects occurred in 5 (14%) of 36 courses and mild reversible alterations in liver function occurred in 3 (19%) of 34 courses. Netilmicin appears to be effective and safe in the treatment of aerobic gram-negative infections.

Adolescent↗
PubMed1979

A prospective controlled investigation of prophylactic trimethoprim/sulfamethoxazole in hospitalized granulocytopenic patients.

Oral trimethoprim/sulfamethoxazole (TMP/SMZ) therapy was investigated in the prophylaxis of infections in granulocytopenia. Hospitalized granulocytopenic patients were allocated at random to receive TMP/SMZ (group 1) or to a control group (group 2). The percentage of febrile granulocytopenic days was significantly reduced in group 1, 19 per cent compared to 39 per cent in group 2 (P less than 0.01). In group 1, there were no bacteremias in 59 episodes of granulocytopenia (909 days). In group 2, there were nine bacteremias in 52 episodes of granulocytopenia (796 days)(P = 0.001). Disseminated candidiasis developed in two patients in each group. Candida occurred in similar numbers in surveillance cultures in both groups; Staphylococcus aureus and Pseudomonas aeruginosa were slightly decreased, and Enterobacteriaceae resistant to TMP slightly increased in group 1. This study suggest that oral prophylactic TMP/SMZ therapy is an effective, well tolerated, easily administered alternative to "gut sterilization" with nonabsorbable antibiotics.

Acute Disease↗
PubMed1979

Influence of mucoidy on antibody coating of Pseudomonas aeruginosa.

Antibody-coated bacteria were found in only two of 34 urine sediments from 19 catheterized patients infected with a single epidemic strain of Pseudomonas aeruginosa, whereas 12 of 19 urine sediments from 16 outpatients contained antibody-coated P. aeruginosa. In urine sediments, individual cells and microcolonies of the epidemic strain of P. aeruginosa were enclosed in ruthenium red (polysaccharide)-positive material. This strain was extremely mucoid when grown in a liquid medium for enhancement of mucoid formation. Renal infections was present in some patients, as determined by the bladder washout test and by titers of antibody in serum, and antibody was present in the urine but not coating P. aeruginosa. We conclude that the mucoid layer interfered with antibody coating of the epidemic strain of P. aeruginosa.

Antibodies, Bacterial↗
PubMed1979

Investigations of the occurrence of gentamicin-resistant Staphylococcus aureus.

During the 19-month period from June 1976 to December 1977, 90 patients became colonized or infected with gentamicin-resistant Staphylococcus aureus (GRS). Of 63 adults, 56 had hospital-acquired GRS, whereas only 9 of 27 children had hospital-acquired GRS (P < 0.001). The other 7 adults and 18 children had GRS present on admission. More than half of those who acquired GRS in the hospital had received prior aminoglycoside therapy. Attack rates were higher in adults than in children and significantly higher on the plastic surgery service than on any other adult service. Phage typing revealed a single-strain outbreak on the plastic surgery ward involving 11 patients, whereas other isolates were of several phage types. Community-acquired GRS occurred more frequently in rural native communities (P < 0.02) and may be related to the use of topical gentamicin. Of 17 native children, 10 were from the same area but there was no common phage type. Agar dilution minimal inhibitory concentration (MIC) testing confirmed that all isolates were gentamicin resistant (MIC >/= 8 mug/ml) and almost all were tobramycin resistant (MIC >/= 8 mug/ml). Although the MIC distribution between gentamicin disk-susceptible and -resistant strains was significantly different, MIC's for 90% of gentamicin disk-resistant strains were </=8 mug of amikacin per ml, and MIC's for 92% of the strains were </=4 mug of netilmicin per ml.

Adolescent↗
PubMed1979

Plasmid-mediated ampicillin resistance in Haemophilus ducreyi.

Three of 19 strains of Haemophilus ducreyi, isolated during a recent outbreak of chancroid, were found to produce beta-lactamase and to harbor a 6.0 x 10(6)-dalton plasmid. Escherichia coli transformed with this plasmid acquired beta-lactamase-mediated resistance to ampicillin. The guanine-plus-cytosine content of the plasmid was found to be 41 mol%. Restriction endonuclease digestion studies suggest that a relatively large portion of the Tn1 translocon is carried by this plasmid. Whereas this plasmid could not be transferred to H. influenzae by mating on membrane filters, a strain of H. ducreyi was able to receive and donate a 30 x 10(6)-dalton ampicillin resistance plasmid from H. influenzae. The ability of H. ducreyi to receive and donate conjugative plasmids may result in the appearance of multiply resistant strains.

Ampicillin↗
PubMed1979

Biotyping of Escherichia coli by a simple multiple-inoculation agar plate technique.

A nine-test system using multiple-inoculation agar plates for biotyping of Escherichia coli is described. Testing of 959 strains resulted in 78 biotypes. On repeated testing, 96% of 182 strains had identical biotypes or differed by only one test. This system provides satisfactory differentiation among strains and is reproducible. Precise standardization of inoculum size is not required. Multiple inoculation allows time and cost-efficient testing of large numbers of strains.

Adult↗
PubMed1978

Prolonged outbreak of nosocomial urinary tract infection with a single strain of Pseudomonas aeruginosa.

Sixty-six hospitalized patients became infected with a single strain of multiply resistant Pseudomonas aeruginosa over a 22-month period. The catheterized urinary tract was the site of the infection in 59 patients (89%). The outbreak was confined to a urology ward until an infected patient from this ward spent 2 weeks in the surgical intensive care unit (SICU). Subsequently patients who acquired the infection in the SICU were discharged to surgical wards throughout the hospital. Urine measuring containers and urometers used in the SICU were the reservoir of the P. aeruginosa; daily sterilization of this equipment terminated the outbreak. Urometers appeared to be the reservoir of the epidemic strain in subsequent outbreaks. Five patients were still infected when they were readmitted 3 to 12 months after the first admission, and therefore represented an additional reservoir of infection.

Cross Infection↗
PubMed1978

Comparison of silver sulfadiazine and gentamicin for topical prophylaxis against burn wound sepsis.

Daily prophylactic application of either 1.0% silver sulfadiazine cream or 0.1% gentamicin cream was compared for effectiveness in preventing bacterial colonization of burn wounds and sepsis. Pseudomonas aeruginosa colonized the wounds of 37% of the 38 patients treated with silver sulfadiazine and 30% of the 33 patients treated with gentamicin; gentamicin-resistant P. aeruginosa colonized the wounds of 21% of the patients treated with gentamicin. Staphylococcus aureus colonization occurred in 55% of the patients treated with silver sulfadiazine, whereas colonization with Candida species occurred in 58% of the patients treated with gentamicin. Although gentamicin-resistant organisms caused no deaths their repeated appearance resulted in discontinuation of prophylaxiz with gentamicin cream. The next year P. aeruginosa strains resistant to gentamicin were isolated from burn wounds of only two patients who had not previously received parenteral therapy with gentamicin or tobramycin. Gentamicin cream should be reserved for treating patients with wounds infected by gentamicin-sensitive P. aeruginosa and those allergic to sulfa drugs. For most patients with burn wounds silver sulfadiazine is safe and effective as an antibacterial agent for topical prophylaxis.

Administration, Topical↗
PubMed1978

Urinary tract infection localization in women.

The site of urinary infection in 51 adult women was determined by the bladder-washout technique (BW). Of the 37 patients with proved upper-tract infection shown by BW, 16 had upper-tract symptoms, three had lower-tract symptoms, and 18 were asymptomatic; 31 had antibody-coated bacteria (ACB), and six had no ACB. Of 14 patients with proved lower-tract infection shown by BW, three had upper-tract symptoms, five had lower-tract symptoms, and six were asymptomatic; none had ACB. All 31 women whose infecting bacteria were coated with antibody proved to have an upper-tract infection shown by BW. A subset of the population of adult women with upper-tract infection have organisms emanating from their ureters at BW localization, which are not coated with antibody. Physicians must be cautious in interpreting results that are negative for ACB.

Adult↗
PubMed1978

Granulocytopenia in hospitalized patients: I. Prognostic factors and etiology of fever.

The clinical course of 126 hospitalized patients during 192 episodes of granulocytopenia and fever was studied. Fever was a regular accompaniment of granulocytopenia, occurring in 94 per cent of granulocytopenic episodes. The mean duration of granulocytopenia (less than 1,000/mm3) was 18 days, with fever (temperature greater than 38 degrees C) being present during 44 per cent of those days. Fever was present during 69 per cent of days with a granulocyte count less than 10/mm3. A presumed infection was present in 86 of 128 febrile granulocytopenic episodes in adults and in 19 of 64 febrile granulocytopenic episodes in children. A fungal infection was found in 11 patients; a viral infection in 23 patients. Bacteremia occurred during 44 granulocytopenic episodes with 16.8 bacteremias/1,000 days of granulocytopenia in adults and 12.7 bacteremias/1,000 days in children. The mortality was 33 per cent per granulocytopenic episode in adults and only 8 per cent per episode in children.

Adolescent↗
PubMed1978

Granulocytopenia in hospitalized patients. II. A prospective comparison of two antibiotic regimens in the empiric therapy of febrile patients.

The results of empiric antibiotic therapy in 126 hospitalized patients with fever during 192 episodes of granulocytopenia were studied. Febrile granulocytopenic patients were randomly allocated to receive either carbenicillin, methicillin and gentamicin, or carbenicillin and cephalothin. The response rate for the two antibiotic regimens was similar, 49 (60 per cent) of 81 responded to the former and 42 (54 per cent) of 78 to the latter. The response rate in patients receiving other antibiotics because of specific indications or counterindications was 19 (58 per cent) of 33. Thirty-nine (35 per cent) of 110 patients who responded to initial antibiotic therapy had an increase in circulating granulocytes of one log10 or more compared to only 10 (12 per cent) of 79 nonresponders with such an increase. The mortality rate in adult patients receiving carbenicillin, methicillin and gentamicin was eight (16 per cent) of 51, compared to 18 (37 per cent) of 49 in those receiving cephalothin and carbenicillin (P less than 0.05). The significance of this difference in the initial response rate or mortality rate between patients treated with the two antibiotic regimens when only patients with documented bacterial infection were considered. Patients who responded to their initial antibiotic regimen, and patients for whose fever no explanation was found, had the best prognosis.

Adolescent↗