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Biomedical subjects

N F Jacobs

Publications and source records attributed to N F Jacobs.

17 recordsLinked to original sources
PubMed1991

Haemophilus influenzae resistance in a community hospital.

We prospectively tabulated all isolates of Haemophilus influenzae at DeKalb Medical Center from 1987 through 1989 to assess the occurrence of antibiotic resistance in patients of different ages. Of 325 total strains isolated, 24% produced beta-lactamase, rendering them resistant to ampicillin and amoxicillin. Antibiotic resistance was as common in patients older than age 60 (24%) as in younger patients (23%). Sensitivity testing by disk diffusion and microdilution techniques on 71 isolates (37 beta-lactamase-positive) showed uniform susceptibility to cefuroxime, cefotaxime, amoxicillin/clavulanate, cefaclor, and chloramphenicol, but three beta-lactamase-positive isolates were resistant to trimethoprim/sulfamethoxazole. The high rate of ampicillin resistance noted in elderly patients has implications for the choice of antimicrobial therapy for these infections.

Adolescent↗
PubMed1979

"Diphtheroid" pneumonia.

We have described a case of pneumonia caused by Corynebacterium CDC Group D2 which was diagnosed by Gram stain of a specimen obtained by transtracheal aspiration and recovery of the organisms from the aspirate specimen in pure culture. Treatment with penicillin was successful.

Aged↗
PubMed1977

Experimental animal infections with Mycoplasma hominis and Ureaplasma urealyticum.

Subcutaneous tissue cavities in mice and guinea pigs were infected with human isolates of Ureaplasma urealyticum and Mycoplasma hominis. The minimal infective dose for M. hominis was as low as less than 10 color-changing units (CCU) for mice and 10(2) CCU for guinea pigs. The minimal infective dose for U. urealyticum was as low as less than 10 CCU for mice and 10(4) CCU for guinea pigs. Mouse infections with either U. urealyticum or M. hominis persisted for 1 day to greater than 4 months. Guinea pigs remained infected for up to 4 weeks. Two M. hominis isolates were similar in their ability to infect subcutaneous tissue cavities but two U. urealyticum isolates varied in their ability to infect the cavities. The histopathology of the M. hominis and U. urealyticum infections was similar: an initial intense polymorphonuclear response with giant cells, followed in 4 weeks by histiocytes and giant cells with some plasma cells and lymphocytes.

Animals↗
PubMed1977

Isolation and characterization of a rough colony type of Neisseria gonorrhoeae.

A new colony type of Neisseria gonorrhoeae was detected in the primary cultures from 8 of 180 men with gonococcal urethritis. This colony type contrasts with those previously described by having a rough and irregular surface. In six of the eight cases, the rough form predominated. The distinctive morphology of the rough colony variant could be maintained indefinitely by selective subculture. By electron microscopy, organisms taken from rough colonies of each of the eight isolates were piliated. Antimicrobial susceptibilities of type 1 and rough clones derived from the same patients were identical for ampicillin, penicillin, tetracycline, and spectinomycin. After inoculation of rough colonies into subcutaneous chambers in mice and guinea pigs, type 1 colonies predominated in cultures of material obtained from the chambers. This new piliated colony type of N. gonorrhoeae may provide an opportunity to investigate factors other than pili that contribute to gonococcal virulence.

Animals↗
PubMed1976

Nongonococcal urethritis.

Nongonococcal urethritis may now account for most cases of symptomatic urethritis seen at VD clinics in the United States. Well-controlled etiologic studies in nongonococcal urethritis have implicated Chlamydia in over 40% of cases but the etiology of Chlamydia-negative cases remains uncertain. Tetracycline provides effective antimicrobial therapy, but tests for cure are often inadequate, and distinguishing relapse and reinfection is difficult. For tetracycline-allergic patients, erythromycin should be used. Control measures to decrease transmission of nongonococcal urethritis are not well established.

Chlamydia Infections↗
PubMed1976

T-strain mycoplasma in the chimpanzee.

Specimens from 4 chimpanzees were cultured for T-strain mycoplasma and Mycoplasma hominis. T-strain mycoplasmas were recovered from the genital tract and throat of a male and the genital tract of his female cagemate; neither had clinical evidence of infection. Two other male chimpanzees were culturally negative for T-strain mycoplasmas. M hominis was not isolated from any of the animals. The chimpanzee may serve as a suitable experimental model for studying the role of T-strain mycoplasmas in human urethritis and reproductive failure.

Animals↗
PubMed1975

Comparison of hemoglobin-free culture media and thayer-martin medium for the primary isolation of Neisseria gonorrhoeae.

Translucent culture media are essential for the determination of gonococcal colony types. In this study two hemoglobin-free, translucent culture media were compared with Thayer-Martin (TM) medium for the primary isolation of Neisseria gonorrhoeae from male urethral specimens. The antibiotic-free translucent medium (GCB) and the translucent medium containing vancomycin, colistin, and nystatin (VCN) were as efficient as TM medium in detecting positive specimens. In fact, VCN medium gave positive results significantly more often than TM medium(P less than 0.05). The amount of growth on positive plates was comparable for all three media. Contaminants were noted most often on GCB medium (P less than 0.0001), and the frequency of contaminants with TM plates exceeded that of VCN plates (P less than 0.0001). The high isolation rate of N. gonorrhoeae with VCN hemoglobin-free culture medium and its lower cost and greater ease of preparation make it a suitable alternative to TM medium for use with male urethral specimens.

Colistin↗
PubMed1975

Use of immunoglobulin coupled to agarose beads for examining the specificity of conjugates.

Preparations of purified immunoglobulins, light chains, and unrelated proteins (used as controls) were covalently linked to agarose beads and used to study the specificity of fluorescein isothiocyanate conjugates. The data demonstrate how these beads can be used to detect immunological and non-immunological reactivity in conjugates. Commercial conjugates, conjugates prepared in this laboratory, and fluorescein-labeled normal immunoglobulins demonstrated high reactivity with control beads unless chromatographed on diethylaminoethyl-cellulose to select for the proper fluorescein-protein ratio. Undesirable immunological reactivity could be demonstrated in commercial conjugates and was shown to be due to anti-light-chain antibody.

Antibody Specificity↗
PubMedDate not supplied

Serologic testing for gonorrhea.

A simple, adequately evaluated serologic test is not now available for use in gonorrhea screening programs. Some of the factors responsible for the relatively low sensitivity and specificity of serologic tests for gonorrhea as compared to cultural techniques are discussed. These include the time required for development of an immunologic response after infection, cross-reactivity with other antigens, and the persistence of antibody after therapy. At present, gonococcal serologic tests may be useful to the clinician in establishing the diagnosis of disseminated gonococcal infection, especially if paired sera demonstrate a change in antibody titer. Current research on the antigenic structure of the gonococcus may lead to the development of improved serologic tests for use in screening programs. However, the performance of any test may vary according to sex of the patient, presence of symptoms, history of prior gonococcal infection, and duration of the current infection. The physician must understand these factors when considering the use of any serologic test for gonorrhea.

False Positive Reactions↗
PubMedDate not supplied

Auxotypes and antibiotic susceptibility patterns of Neisseria gonorrhoeae from disseminated and local infections.

The arginine-hypoxanthine-uracil auxotype has been linked with the propensity of gonococci to cause disseminated infections. Gonococci recovered from 25 patients with disseminated gonococcal infections were compared with gonococci recovered from matched controls, patients with uncomplicated gonorrhea selected during the same month. Minimal inhibitory concentrations of penicillin, tetracycline, erythromycin, and ampicillin, and the nutritional requirements (auxotypes) for proline alone, arginine alone, arginine, hypoxanthine and uracil together, serine alone and cysteine-cystine (wild type) were analyzed by discriminant analysis. Significant susceptibility to penicillin characterized strains causing disseminated infection, and a proline requirement was the most common auxotype (48%) among strains isolated in Atlanta. Together the minimal inhibitory concentration of penicillin and the proline auxotype best separated the strains causing gonorrhea. The arginine-hypoxanthine-uracil auxotype was was found in only 24% of strains causing disseminated infections. A trait other than auxotype must determine the capacity of the organisms to disseminate.

Adult↗
PubMedDate not supplied

Experimental infection of the chimpanzee urethra and pharynx with Chlamydia trachomatis.

An isolate of Chlamydia trachomatis obtained from a man with nongonococcal urethritis was used to produce experimental urethral and pharyngeal infections in chimpanzees. After urethral inoculation of 8 X 10(1) inclusion-forming units (IFU), infections were established in three of three animals; urethral discharges developed in two. The infections persisted for five to nine weeks. Larger inocular (7 X 10(2) and 1 X 10(5) IFU) produced pharyngeal infections in two animals. The third animal's pharynx was not infected by 1 X 10(5) IFU. Chlamydial complement-fixing antibodies increased significantly in sera of two of three animals. This study provides an animal model for study of mucosal infection by C. trachomatis. The relative resistance of the chimpanzee pharynx to infection parallels clinical observations in man.

Animals↗