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Biomedical subjects

A R Ronald

Publications and source records attributed to A R Ronald.

At least 91 records · Page 5Linked to original sources
PubMed1986

AIDS virus infection in Nairobi prostitutes. Spread of the epidemic to East Africa.

The acquired immunodeficiency syndrome (AIDS) is epidemic in Central Africa. To determine the prevalence of AIDS virus infection in East Africa, we studied 90 female prostitutes, 40 men treated at a clinic for sexually transmitted diseases, and 42 medical personnel in Nairobi, Kenya. Antibody to human T-cell lymphotropic virus Type III (HTLV-III) was detected in the serum of 66 percent of prostitutes of low socioeconomic status, 31 percent of prostitutes of higher socioeconomic status, 8 percent of the clinic patients, and 2 percent of the medical personnel. The presence of the antibody was associated with both immunologic and clinical abnormalities. The mean T-cell helper/suppressor ratio was 0.92 in seropositive prostitutes and 1.82 in seronegative prostitutes (P less than 0.0001). Generalized lymphadenopathy was present in 54 percent of seropositive prostitutes and 10 percent of seronegative prostitutes (P less than 0.0001). No constitutional symptoms, opportunistic infections, or cases of Kaposi's sarcoma were present. Our results indicate that the epidemic of AIDS virus infection has, unfortunately, spread extensively among urban prostitutes in Nairobi, Kenya. Sexual exposure to men from Central Africa was significantly associated with HTLV-III antibody among prostitutes, suggesting transcontinental spread of the epidemic.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Isolation and identification of Haemophilus ducreyi in a clinical laboratory.

Routine procedures used to isolate Haemophilus ducreyi in a busy laboratory are reported. Identification was based on colony morphology and nutritional and biochemical properties of 120 fresh isolates of H. ducreyi. These isolates grew very well on Gonococcal Agar and Mueller-Hinton Agar incubated at 34 degrees C in candle extinction jars containing moistened filter paper. Colonies varied in size, giving a polymorphic appearance. They were smooth, dome-shaped, and buff-yellow to grey in colour, and measured 2 mm in diameter. They could be pushed intact across the agar surface. By microscopic examination of gram-stained smears the isolates were gram-negative coccobacilli arranged in short chains, clumps or whorls and occasionally in typical "rail track" arrangements. Individual bacteria showed bipolar staining. Colonies autoagglutinated in saline. All strains were catalase-negative and did not produce indole or H2S. They were oxidase- and beta-lactamase positive and required X but not V factor for growth. Now that reliable techniques have been developed and characteristics established it is possible for most clinical laboratories to isolate and identify this organism from most patients with chancroid.

Chancroid↗
PubMed1986

Clinical evaluation of rosoxacin for the treatment of chancroid.

One hundred seven men with Haemophilus ducreyi-positive chancroid were assigned to receive 300 mg of rosoxacin as a single dose or 150 mg twice daily for 3 days. Ulcers and buboes were followed clinically and bacteriologically for 1 month. Of 40 evaluable males on the 3-day regimen, 38 (95%) were cured, while only 14 of 23 (61%) males on the single-dose regimen were cured; this regimen was discontinued. There was one ulcer relapse at day 21 in both groups; the one relapse in the single-dose group had a persistent culture-positive bubo. Eight of nine (89%) buboes followed to the endpoint on the 3-day rosoxacin regimen were cured, versus three of six (50%) on the single-dose regimen. Adverse effects were mainly related to the central nervous system but were minor and did not require intervention. None of the treatment failures was due to organisms resistant to rosoxacin, and failure of the single-dose regimen presumably was related to duration of tissue levels rather than to drug resistance. Administration of 150 mg of rosoxacin twice daily for 3 days is an effective regimen for the therapy of chancroid and is a reasonable alternative to other short-course regimens.

4-Quinolones↗
PubMed1986

Characterization of a Haemophilus ducreyi mobilizing plasmid.

The OriV site of Haemophilus ducreyi mobilizing plasmid pHD147, determined by replication in Escherichia coli polA, is located close to the OriT site. The OriT site, located by recombination-proficient and -deficient cells, and the OriV site map in a region of pHD147 homologous to the beta-lactamase-specifying plasmids of H. ducreyi and Neisseria gonorrhoeae.

Chromosome Mapping↗
PubMed1986

Three day oral course of Augmentin to treat chancroid.

Amoxycillin and clavulanic acid (Augmentin; Beecham Research Laboratories) was used to treat patients with bacteriologically proved chancroid in three different dose regimens. A single dose of Augmentin (amoxycillin 3 g, clavulanic acid 350 mg) was found to be ineffective. A similar dose repeated after 24 hours was equally ineffective, but a dose (amoxycillin 500 mg, clavulanic acid 250 mg) given every 8 hours for three days was found to be effective. The drug was well tolerated and no side effects were noted in any of the patients treated.

Administration, Oral↗
PubMed1985

Antimicrobial cream susceptibility testing.

Utilizing a recently described rapid needle extrusion method for determining the sensitivities of burn wound isolates, we have compiled data on the resistance patterns of over 250 isolates from our burn unit. Major isolate groups were Staphylococcus aureus, Pseudomonas aeruginosa, various Enterobacteriaceae and Enterococci. Excellent correlation was exhibited between the inhibitory zone sizes and the minimal inhibitory concentration for 120 organisms tested. Utilizing the needle extrusion sensitivities to facilitate the selection of the burn creams, a significant reduction in the microbiologic flora of the burn wound was noted. The utilization of this technique in the selection of burn creams deserves controlled trials to assess whether changes in topical therapy might alter clinical outcome.

Administration, Topical↗
PubMed1985

Role of lipopolysaccharide and complement in susceptibility of Haemophilus ducreyi to human serum.

The role of lipopolysaccharide (LPS) in the susceptibility of Haemophilus ducreyi to human serum and the mechanism of complement activation by serum-susceptible (Sers) strains were investigated. Serum treated with 2 mM Mg2+ and 20 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid was nonbactericidal, but inulin-treated serum remained bactericidal. Absorption of serum with heat-killed whole cells of an Sers strain removed its bactericidal activity against the absorbing strain and also against other Sers strains. LPS obtained from Sers strains inhibited the bactericidal activity of serum against all Sers strains, whereas LPS from serum-resistant (Serr) strains and an Serr isogenic strain did not. However, high concentrations of LPS from the Serr strain inhibited the bactericidal activity of serum, an indication that part of the structural site involved in serum susceptibility is retained in the LPS of this strain. The LPS of Sers strains exhibited higher anticomplement activity than the LPS of Serr strains. These findings suggest that the classical pathway of complement activation is involved in the serum killing of H. ducreyi and that LPS composition may contribute to their susceptibility to complement-mediated serum bactericidal activity.

Animals↗
PubMed1985

Nystatin prophylaxis of fungal colonization and infection in granulocytopenic patients: correlation of colonization and clinical outcome.

Nystatin, one million units every four hours, was prospectively studied as a prophylactic antifungal agent in 164 neutropenic patients who were not initially colonized by fungi: 104 received nystatin and 60 served as controls. Fungal colonization occurred in 68/104 (65%) nystatin recipients and in 43/60 (71%) controls. However, nystatin significantly reduced multiple body site colonization and persistent oropharyngeal colonization. Despite these alterations in colonization profile, 16/104 (15%) nystatin recipients developed disseminated fungal infections, as compared to 5/60 (8%) control patients (0.5 greater than p greater than 0.1, N.S). Differences in the clinical course of colonized and non-colonized patients were observed. Eighteen of 111 (16%) colonized patients had afebrile clinical courses as compared to 16/53 (30%) non-colonized patients (p less than 0.05). Twenty-nine of 93 (31%) febrile episodes in colonized patients failed to respond to empiric antibiotic therapy as compared to 3/37 (8%) episodes in non-colonized patients (p less than 0.01). Disseminated fungal infections were diagnosed in 19/111 (17%) of colonized patients, as compared to 1/53 (2%) non-colonized patients (p less than 0.02). We conclude that colonized patients are more likely to develop febrile clinical courses, to fail to respond to empiric antibiotic therapy, and to develop disseminated fungal infection. Nystatin altered colonization patterns but did not prevent disseminated fungal infection.

Adolescent↗
PubMed1985

Emergence of tobramycin-resistant S. epidermidis possessing aminoglycoside modifying enzymes and bacteremic superinfection during empiric therapy of febrile neutropenic episodes.

During a randomized clinical trial comparing tobramycin plus ticarcillin to netilmicin plus ticarcillin as empiric therapy of febrile neutropenic patients, Staphylococcus epidermidis emerged as the predominate superinfecting pathogen in tobramycin recipients. Overall clinical response was 68% (44/65 responding) in tobramycin/ticarcillin recipients and 73% (45/62) in netilmicin/ticarcillin recipients. However, 5/65 tobramycin/ticarcillin treated episodes were complicated by bacteremic superinfection with Staphylococcus epidermidis, as compared to 0/62 netilmicin/ticarcillin treated episodes (p less than 0.05). Four of the five bacteremic strains produced aminoglycoside adenylating enzyme ANT 4', 4''. Prior colonization of patients with identical strains was demonstrated by plasmid profile analysis, antibiograms and biotyping with the API Staph-Ident system. During the trial, 36 consecutive patients were studied for colonization patterns with coagulase-negative staphylococci. S. epidermidis accounted for 566/831 (68%) isolates of coagulase-negative staphylococci recovered from surveillance cultures. Tobramycin-resistant strains were acquired in 2/17, 4/12 and 9/14 patients during trimethoprim/sulfamethoxazole, netilmicin/ticarcillin and tobramycin/ticarcillin therapy, respectively. Prior to aminoglycoside therapy, 77% of strains were susceptible to less than or equal to 8 micrograms/ml of tobramycin, but only 35% and 28% were susceptible to tobramycin after initiation of tobramycin/ticarcillin and netilmicin/ticarcillin therapy, respectively. In contrast, greater than or equal to 93% of isolates were susceptible to netilmicin before and after aminoglycoside therapy. Absence of several sites susceptible to modification by aminoglycoside inactivating enzymes produced by staphylococci may give netilmicin a therapeutic advantage in the therapy of febrile neutropenic patients.

Adult↗
PubMed1985

Adherence of Escherichia coli to epithelial cells in the pathogenesis of urinary tract infection.

The role of bacterial adherence in the pathogenesis of recurrent urinary tract infection was investigated using an I125 E. coli-epithelial cell assay. In vitro bacterial adhesion to buccal, vaginal epithelial and uroepithelial cells of periurethral or rectal E. coli isolated from each subject was measured in 21 patients with recurrent urinary tract infection and 10 normal controls. Percent adherence of E. coli to buccal, vaginal, and uroepithelial cells was significantly (p less than .005) greater in patients with recurrent infection, compared with controls (32.9 +/- 4.0 vs. 14.1 +/- 7.3; 32.3 +/- 8.1 vs. 15.4 +/- 6.6; 34.7 +/- 5.6 vs. 17.1 +/- 4.2, mean +/- S.D., respectively). For both patients and controls, correlation in adherence between vaginal, uroepithelial, and buccal cells was observed. There were no differences in adherence between patients with or without periurethral colonization with E. coli, and adherence was not influenced by age. Patients receiving antimicrobial prophylaxis had a significantly (p less than .005) lower mean adherence to vaginal (26.7 +/- 3.7 vs. 35.1 +/- 4.1) and uroepithelial (30.4 +/- 2.8 vs. 34.6 +/- 3.2) cells, but not for buccal epithelial cells, compared with patients not receiving prophylaxis. These data support the hypothesis that increased receptivity of epithelial cells for bacteria plays a role in the increased frequency of vaginal colonization and subsequent infection in women who experience recurrent urinary tract infection.

Adhesiveness↗
PubMed1984

Single-dose kanamycin therapy of gonococcal ophthalmia neonatorum.

117 infants with gonococcal ophthalmia neonatorum, including 27 with infections due to penicillinase-producing Neisseria gonorrhoeae, were treated as outpatients with five different regimens of single-dose intramuscular kanamycin (75 mg or 150 mg) with saline eye washes, gentamicin eye ointment, or chloramphenicol eye drops. There were no treatment failures among 68 patients treated with 75 mg or 150 mg kanamycin and gentamicin eye ointment (for 3 days). However, the minimum and maximum cumulative probabilities of cure of single-dose kanamycin with saline eye washes (for 3 days) were only 60% and 89%. 1 patient of 15 treated with 150 mg kanamycin plus chloramphenicol eye drops did not respond to treatment. Postgonococcal conjunctivitis developed in 14 (12%) infants, of whom 13 had positive cultures for Chlamydia trachomatis. Nasopharyngeal infection with N gonorrhoeae was eradicated in 9 of 11 infants colonised.

Administration, Topical↗
PubMed1984

Advances in the treatment of urinary tract infection.

Single dose treatment regimens are currently the treatment of choice in women with acute urethrocystitis. Women who have concomitant asymptomatic renal infections will have a recurrence and require further investigation and more conventional 14-day treatment regimens. Single dose treatment is a specific and moderately sensitive diagnostic aid for women with urinary infection. Further carefully planned studies are required to determine optimal treatment regimens for women with renal infection and men with infections originating in the kidneys or prostate.

Anti-Bacterial Agents↗
PubMed1984

Randomized controlled trial comparing trimethoprim/sulfamethoxazole and trimethoprim for infection prophylaxis in hospitalized granulocytopenic patients.

The clinical and microbiologic efficacy of trimethoprim alone and trimethoprim/sulfamethoxazole for infection prevention was evaluated in 75 patients during 92 episodes of granulocytopenia. Ultimately, 60 patients were evaluable during 77 episodes of granulocytopenia, 36 episodes in the trimethoprim group and 41 episodes in the trimethoprim/sulfamethoxazole group. The incidence of infection was higher in the trimethoprim group (50 percent) than in the trimethoprim/sulfamethoxazole group (39 percent), but this did not reach statistical significance. Trimethoprim did not appear to be as protective as trimethoprim/sulfamethoxazole when the granulocyte count was less than 100/mm3. In patients receiving trimethoprim/sulfamethoxazole, aerobic gram-negative bacilli cleared from fecal surveillance cultures more often and new aerobic gram-negative bacilli were acquired less often than in those receiving trimethoprim alone (p less than 0.05). More myelosuppression was observed among patients receiving trimethoprim/sulfamethoxazole (p less than 0.001). These observations suggest that trimethoprim alone may not be optimal for preventing colonization and infection in granulocytopenic patients and that combination with other agents may be necessary to increase the spectrum of activity. Trimethoprim/sulfamethoxazole itself may predispose toward an increased risk of infection by prolonging myelosuppression.

Adult↗