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J S Knapp

Publications and source records attributed to J S Knapp.

At least 37 records · Page 2Linked to original sources
PubMed1995

Susceptibilities of Chlamydia trachomatis isolates causing uncomplicated female genital tract infections and pelvic inflammatory disease.

The in vitro susceptibilities of 45 recent clinical isolates of Chlamydia trachomatis obtained from women with asymptomatic genital tract infection, mucopurulent cervicitis, or pelvic inflammatory disease to doxycycline, azithromycin, ofloxacin, and clindamycin were determined. In addition, susceptibilities of 12 isolates to amoxicillin and trimethoprim-sulfamethoxazole were also determined. Isolates also were serotyped with a panel of monoclonal antibodies specific for chlamydial major outer membrane protein; 24 of 45 (53%) belonged to serovars Ia and E. For all isolates, the MIC range of doxycycline was 0.008 to 0.06 micrograms/ml, for trimethoprim-sulfamethoxazole it was 0.03 to 0.25 micrograms/ml, for azithromycin it was 0.125 to 2.0 micrograms/ml, for ofloxacin it was 0.5 to 1.0 micrograms/ml, for clindamycin it was 0.25 to 2.0 micrograms/ml, and for amoxicillin it was 0.25 to 4.0 microgram/ml. The ranges of minimum chlamydiacidal concentrations were generally 1 to 4 dilutions above the MICs of most agents, with a rank order similar to those of the MICs. Comparing the minimum chlamydiacidal concentrations for 90% of isolates tested, isolates causing asymptomatic infection belonged to a greater variety of serovars and were relatively more susceptible to doxycycline and azithromycin than isolates causing mucopurulent cervicitis or pelvic inflammatory disease; these differences in susceptibility were not detected among the other study agents. These data indicate that additional studies are needed to better define the apparent association of certain chlamydial serovars with the clinical severity of disease and the in vitro susceptibilities to certain antimicrobial agents.

Anti-Bacterial Agents↗
PubMed1995

In vitro activity of a new fluoroquinolone, CP-99,219, against strains of Neisseria gonorrhoeae.

The susceptibilities of 216 strains of Neisseria gonorrhoeae to a new fluoroquinolone, CP-99,219 were determined. For strains for which the MICs of ciprofloxacin were < or = 0.06 microgram/ml, the MICs at which 90% of the isolates are inhibited (MIC90s) of CP-99,219, ciprofloxacin, and ofloxacin were 0.008, 0.015, and 0.03 microgram/ml, respectively. For strains for which the MICs of ciprofloxacin were 0.125 to 0.5 microgram/ml, the MIC90s of CP-99,219, ciprofloxacin, and ofloxacin were 0.06, 0.25, and 0.5 microgram/ml, respectively. For strains for which the MICs of ciprofloxacin and ofloxacin were 2.0 micrograms/ml, the MIC of CP-99,219 was 0.25 microgram/ml.

Anti-Infective Agents↗
PubMed1994

Antimicrobial susceptibilities of Neisseria gonorrhoeae strains representing five distinct resistance phenotypes.

The susceptibilities of 109 strains of Neisseria gonorrhoeae to penicillin G, tetracycline, amoxicillin-clavulanic acid, cefotetan, cefoxitin, ceftriaxone, ciprofloxacin, and fleroxacin were determined. The activities of cefmetazole, cefuroxime, cefixime, and ofloxacin were also determined against 62 of these strains. Strains represented penicillin-susceptible (Pen(s)) N. gonorrhoeae; penicillinase-producing N. gonorrhoeae (PPNG) possessing 2.9-, 3.05-, 3.2-, or 4.4-MDa beta-lactamase plasmids; strains with high-level, plasmid-mediated tetracycline resistance (TRNG); strains with plasmid-mediated resistance to penicillin and tetracycline; and strains with chromosomally mediated resistance to penicillin and tetracycline (CMRNG). Ceftriaxone, cefixime, and ciprofloxacin were the most active agents tested against all strains. Pen(s), TRNG, and PPNG strains possessing a 3.2-MDa beta-lactamase plasmid were more susceptible to amoxicillin-clavulanic acid, extended- and broad-spectrum cephalosporins, and quinolones than were either PPNG strains possessing a 2.9-, a 3.05-, or a 4.4-MDa beta-lactamase plasmid or CMRNG strains.

Anti-Bacterial Agents↗
PubMed1994

Antimicrobial susceptibilities of Neisseria gonorrhoeae strains isolated in Surabaya, Indonesia.

Until recently, the only common strains of antimicrobial agent-resistant Neisseria gonorrhoeae detected in Indonesia were penicillinase-producing N. gonorrhoeae (PPNG) strains. Despite the spread of resistance to other antimicrobial agents among N. gonorrhoeae in Southeast Asia, surveillance for such resistance in Indonesia has been limited. We evaluated the in vitro susceptibilities of 86 N. gonorrhoeae isolates from female sex workers in Surabaya, Indonesia, to 13 antimicrobial agents. Of the 86 isolates, 89% were resistant to penicillin (MIC, > or = 2.0 micrograms/ml), 98% were resistant to tetracycline (MIC, > or = 2.0 micrograms/ml), 18.1% were resistant to spectinomycin (MIC, > or = 128.0 micrograms/ml), and 97.7% showed decreased susceptibility to thiamphenicol (MIC, 1 to 2 micrograms/ml). Thus, thiamphenicol and spectinomycin may be approaching the end of their usefulness as the drugs of choice for the treatment of gonococcal infections in Surabaya. While the susceptibilities of N. gonorrhoeae to cephalosporins (ceftriaxone, cefixime, and cefoxitin) and fluoroquinolones (ciprofloxacin and ofloxacin) are universal, these drugs have not been used because they are more expensive in Indonesia than thiamphenicol. We conclude that Surabaya had the highest reported rate of penicillin and tetracycline resistance among the Southeast Asian countries and that cephalosporins or fluoroquinolones should be reasonable alternatives for the treatment of gonorrhea in this locale.

Anti-Bacterial Agents↗
PubMed1994

Susceptibility of Neisseria gonorrhoeae associated with pelvic inflammatory disease to cefoxitin, ceftriaxone, clindamycin, gentamicin, doxycycline, azithromycin, and other antimicrobial agents.

We determined the susceptibilities, by the agar dilution method, of 84 recent clinical isolates of Neisseria gonorrhoeae obtained from women with pelvic inflammatory disease in the United States to the following antimicrobial agents: penicillin, cefoxitin, cefotetan, ceftriaxone, ceftizoxime, cefixime, tetracycline, doxycycline, ciprofloxacin, ofloxacin, erythromycin, azithromycin, clindamycin, and gentamicin. Twenty-five percent of the isolates were resistant to penicillin and 20% were resistant to tetracycline. In comparison, doxycycline was more active than tetracycline and azithromycin was more active than erythromycin in vitro. Ceftriaxone, ceftizoxime, and cefixime were equally active against penicillin-susceptible isolates, but they had different in vitro activities against gonococcal isolates possessing chromosomally mediated resistance to penicillin. Overall, cefoxitin was slightly more active than cefotetan and ciprofloxacin was more active in vitro than ofloxacin, especially against N. gonorrhoeae with chromosomally mediated resistance. Criteria for the interpretation of susceptibility data for N. gonorrhoeae are not available for clindamycin or gentamicin, but for at least half of all isolates, including penicillin-susceptible isolates, at least 4 micrograms of clindamycin or gentamicin per ml was required to inhibit growth in vitro.

Anti-Bacterial Agents↗
PubMed1994

Persistence of Neisseria gonorrhoeae strains with decreased susceptibilities to ciprofloxacin and ofloxacin in Cleveland, Ohio, from 1992 through 1993.

Twenty-five isolates of beta-lactamase-negative strains of Neisseria gonorrhoeae exhibiting decreased susceptibilities to ciprofloxacin (MIC, > or = 0.125 microgram/ml) were isolated from men with uncomplicated gonococcal urethritis in Cleveland, Ohio, from January 1992 through June 1993. The strains belonged to three auxotype-serovar classes: Pro-IB-1 (2 isolates), Pro-IB-2 (21 isolates), and Pro-IB-3 (2 isolates). MICs for strains were in the intermediate or resistant categories for penicillin, the intermediate or susceptible categories for tetracycline (with the exception of one strain that had acquired the 25.2-MDa TetM-containing plasmid) and cefoxitin, and the susceptible categories for ceftriaxone and cefixime (MICs, < or = 0.25 microgram/ml) and spectinomycin (MIC, < or = 256 micrograms/ml). MICs for strains were also in the susceptible category for ofloxacin (MIC, 0.25 microgram/ml) and in categories higher than susceptible for ciprofloxacin (MICs, 0.125 to 0.25 microgram/ml) and ofloxacin (MIC, 0.5 microgram/ml). The diameters of zones of inhibition for these strains ranged from 31 to 39 mm for ciprofloxacin to 28 to 35 mm for ofloxacin. The persistence of these strains over an 18-month period supports the need for routine sentinel surveillance and monitoring of gonococcal isolates, particularly posttreatment isolates, for resistance to quinolones when these agents are used for the primary therapy of uncomplicated gonorrhea.

Ciprofloxacin↗
PubMed1994

Emerging in vitro resistance to quinolones in penicillinase-producing Neisseria gonorrhoeae strains in Hawaii.

The susceptibilities of 37 penicillinase-producing strains of Neisseria gonorrhoeae (PPNG), isolated in Hawaii from December 1991 through January 1994, were determined to ciprofloxacin and ofloxacin, fluoroquinolone agents currently recommended by the Centers for Disease Control and Prevention as alternative regimens for the treatment of uncomplicated gonorrhea. Nine isolates (24.3%) exhibited decreased susceptibilities (MICs, > or = 0.06 microgram/ml) to ciprofloxacin and ofloxacin. Ciprofloxacin MICs for three isolates (8.1%) were 2.0 micrograms/ml; these isolates belonged to the auxotype/serovar class Pro/IB-7 and possessed the 3.2-MDa beta-lactamase and the 24.5-MDa conjugative plasmids. Six strains for which ciprofloxacin MICs were 0.06 to 0.125 microgram/ml belonged to a variety of gonococcal phenotypes. Strains for which ciprofloxacin MICs were 2.0 micrograms/ml were isolated from persons who had traveled to, or were sexual contacts of persons who had recently traveled to, Southeast Asia. Persons infected with these isolates had been treated with ceftriaxone (250 mg intramuscularly, single dose); therefore, none of these cases were associated with clinical failure following the use of fluoroquinolone therapy. Further studies are needed to confirm the clinical and public health significance of increased in vitro resistance to ciprofloxacin and ofloxacin in N. gonorrhoeae.

Ciprofloxacin↗
PubMed1993

Sentinel surveillance for antimicrobial resistance in Neisseria gonorrhoeae--United States, 1988-1991. The Gonococcal Isolate Surveillance Project Study Group.

PROBLEM/CONDITION: The prevalence of antimicrobial resistance in Neisseria gonorrhoeae in the United States has been increasing since the mid-1970s. DESCRIPTION OF SYSTEM: The Gonococcal Isolate Surveillance Project (GISP) was established in 1986 to monitor trends of antimicrobial resistance in N. gonorrhoeae. GISP is a sentinel surveillance system consisting of 26 publicly funded sexually transmitted disease clinics and five regional laboratories. At each clinic, urethral isolates are obtained from the first 20 men diagnosed with gonorrhea each month; these isolates are shipped to one of the regional laboratories, where the susceptibilities of the organisms to a panel of antibiotics are determined. REPORTING PERIOD COVERED: This report describes the results of surveillance for antimicrobial resistance in N. gonorrhoeae from January 1991 through December 1991. These results are compared with data obtained from January 1988 through December 1990. RESULTS AND INTERPRETATION: In the 1991 GISP sample, 32.4% of isolates were resistant to penicillin or tetracycline. The proportions of isolates with high-level, plasmid-mediated resistance to penicillin, tetracycline, or both drugs have increased significantly (p < 0.001) in the GISP sample during 1988-1991. No documented clinical treatment failures have been related to decreased susceptibility of N. gonorrhoeae to either ceftriaxone or ciprofloxacin, which belong to the classes of antibiotics currently recommended for gonococcal therapy. ACTION TAKEN: Because of the demonstrated ability of N. gonorrhoeae to develop resistance to antimicrobial agents, surveillance to guide therapy recommendations will be continued.

Ceftriaxone↗
PubMed1993

In vitro susceptibilities of isolates of Haemophilus ducreyi from Thailand and the United States to currently recommended and newer agents for treatment of chancroid.

We determined the in vitro susceptibilities of 54 isolates of Haemophilus ducreyi from Thailand (29 isolates) and San Francisco (25 isolates) to penicillin G, tetracycline, amoxicillin-clavulanic acid, ceftriaxone, cefixime, erythromycin, azithromycin, ciprofloxacin, ofloxacin, and trimethoprim-sulfamethoxazole. Isolates were susceptible to < or = 0.25 microgram of ceftriaxone per ml, < or less 0.5 microgram of cefixime per ml, < or = 0.125 microgram of ciprofloxacin per ml, and < or = 0.06 microgram of ofloxacin per ml. Erythromycin was active against all isolates (MIC for 90% of isolates tested, 0.25 microgram/ml), as was azithromycin (MIC, < or = micrograms/ml). In contrast, all but one isolate were resistant to > or = 8.0 micrograms of tetracycline per ml, 11.1% of the isolates were resistant to and 40.9% of the isolates were resistant to trimethoprim-sulfamethoxazole (MIC, > or = 4/76 microgram/ml.)

Anti-Bacterial Agents↗
PubMed1993

Incidence of Neisseria gonorrhoeae isolates negative by Syva direct fluorescent-antibody test but positive by Gen-Probe accuprobe test in a sexually transmitted disease clinic population.

To determine the accuracy of the Syva (Palo Alto, Calif.) direct fluorescent-antibody (DFA) test in comparison with the Gen-Probe (San Diego, Calif.) Accuprobe culture confirmation test, we tested 395 isolates of Neisseria gonorrhoeae from cultures obtained from patients attending a sexually transmitted disease clinic from 1 July 1991 through 30 June 1992. All isolates were tested for DFA reactivity with a polyclonal reagent (Difco Laboratories, Detroit, Mich.) and a monoclonal reagent (Syva, Inc., direct specimen test) and for specific molecular probe reactivity by the Gen-Probe Accuprobe culture confirmation test for N. gonorrhoeae. The 395 isolates gave positive results for the Gen-Probe culture confirmation test and the Difco polyclonal direct specimen test. However, 18 (4.6%) of the isolates were negative for N. gonorrhoeae by the Syva DFA test. With the exception of six beta-lactamase-positive isolates, all isolates that were negative by Syva DFA were sensitive to penicillin, tetracycline, spectinomycin, and ceftriaxone by disk-diffusion susceptibility testing. Auxotyping and serotyping studies indicated that strains negative by Syva DFA consisted of several variants. The frequency of N. gonorrhoeae isolates showing negative results by Syva DFA in this patient population ranged from 0 to 11.5%/month. Laboratories using only the Syva DFA test for confirmation of N. gonorrhoeae may incur a significant risk of misidentification.

Adolescent↗
PubMed1992

Correlation between in vitro antimicrobial susceptibilities and beta-lactamase plasmid contents of isolates of Haemophilus ducreyi from the United States.

We determined the susceptibilities of 94 strains of Haemophilus ducreyi isolated in various municipalities in the United States between 1982 and 1989 to the following antimicrobial agents: amoxicillin-clavulanic acid, ceftriaxone, erythromycin, azithromycin, ciprofloxacin, ofloxacin, trimethoprim, and spectinomycin. Ceftriaxone (MIC, less than or equal to 0.008 micrograms/ml), azithromycin (MIC, less than or equal to 0.125 micrograms/ml), erythromycin (MIC, less than or equal to 0.125 micrograms/ml), ciprofloxacin (MIC, less than or equal to 0.25 micrograms/ml), and ofloxacin (MIC, less than or equal to 0.25 micrograms/ml) were highly active against all isolates. Amoxicillin-clavulanic acid (MICs, 0.25 to 8.0 micrograms/ml), trimethoprim (MICs, 0.06 to 16.0 micrograms/ml), and spectinomycin (MICs, 2.0 to greater than or equal to 32.0 micrograms/ml) were less active against these isolates. Isolates possessing the 5.7-MDa beta-lactamase plasmid were less susceptible to erythromycin, trimethoprim, and spectinomycin than were isolates possessing the 3.2-MDa beta-lactamase plasmid. The susceptibilities of plasmidless isolates to erythromycin, trimethoprim, and spectinomycin were distributed bimodally; the median MIC for the more susceptible plasmidless isolates corresponded to that for isolates with the 3.2-MDa plasmid, and the median MIC for the less susceptible plasmidless isolates corresponded to that for isolates with the 5.7-MDa plasmid. Thus, plasmid profiles may be valuable markers for geographical variations in antimicrobial susceptibilities of H. ducreyi strains that may indicate the relative efficacy of regimens for the treatment of chancroid. Of the regimens recommended by the U.S. Public Health Service for the treatment of chancroid, our results support the use of erythromycin, ceftriaxone, and ciprofloxacin, and perhaps ofloxacin, but suggest that amoxicillin-clavulanic acid and sulfamethoxazole-trimethoprim should be used with caution.

Anti-Bacterial Agents↗
PubMed1991

Prevalence of gene sequences coding for hypervariable regions of Opa (protein II) in Neisseria gonorrhoeae.

Opas (protein IIs) are a family of surface-exposed proteins of Neisseria gonorrhoeae. Each strain of N. gonorrhoeae has multiple (10-11) genes encoding for Opas. Identifiable elements in opa genes include the coding repeat within the signal sequence, conserve 5' and 3' regions, and hypervariable regions (HV1 and HV2) located within the structural gene. N. gonorrhoeae strains appear to have many biological properties in common that are either HV-region-mediated or associated with the presence of specific HV regions, suggesting that HV regions could be found in many clinical isolates. Oligonucleotides from three source strains representing three conserved regions of opa, 12 HV1 regions, and 14 HV2 regions were used by dot blot analysis to probe 120 clinical isolates of N. gonorrhoeae. The probe for the coding repeat hybridized to all 120 strains, the 3' conserved-region probe reacted with 98% of the strains, and the 5' conserved-region probe with 90% of the strains. Nine HV1 probes hybridized to 3.3-39.2% of the strains, and 13 of the HV2 probes hybridized to 1.7-25% of the isolates. Analysis of the number of probes that hybridized to each of the isolates showed that 19% did not hybridize with any of the HV1 probes and 25% did not hybridize with any of the HV2 probes. Approximately three-quarters of the isolates hybridized with one, two or three of the HV1 probes or one, two or three of the HV2 probes; 89% of the isolates hybridized to least one HV1 or one HV2 probe. The data indicate that some genes encoding HV regions of N. gonorrhoeae Opa proteins are widely distributed in nature.

Bacterial Outer Membrane Proteins↗
PubMed1991

Binding of S protein by Neisseria gonorrhoeae and potential role in invasion.

An agglutination assay was used to examine the binding of purified human S protein (vitronectin, serum spreading factor) to 201 clinical isolates of Neisseria gonorrhoeae. Strains belonging to the protein IA serovars were significantly (P less than 0.001) more reactive in agglutination tests with human S protein and were more serum resistant than strains belonging to the protein IB serovars. The strains from patients with disseminated infections belonged predominantly to the IA serovar (19 of 23) and, with the exception of IA-4 and certain IB serovars, avidly agglutinated with S protein. The serovar IA-4 and IB strains isolated from joint or cerebrospinal fluid failed to agglutinate with S protein and appeared to be less serum resistant than most other IA isolates. Cysteine hydrochloride or 2-mercaptoethanol inhibited agglutination of S protein and a more than twofold increase in resistance to killing by fresh human serum following preincubation with S protein; the serum-sensitive parent strain did not agglutinate S protein, and serum resistance was not increased following preincubation with this protein. Binding of S protein by gonococci may represent a novel pathogenic mechanism that can contribute to serum resistance.

Agglutination↗
PubMed1991

Novel plasmid combinations in Haemophilus ducreyi isolates from Thailand.

Thirty isolates of Haemophilus ducreyi collected in Thailand in 1984 were characterized by plasmid content. Three novel plasmids with estimated molecular masses of 1.8, 2.6, and 2.8 MDa were observed in 29 isolates, in addition to the 3.2-, 5.7-, and 7.0-MDa beta-lactamase and 4.4-MDa sulfonamide resistance plasmids. At least three of the seven plasmids were observed in each of the 29 isolates. The number and diversity of plasmids observed in these isolates of H. ducreyi distinguish them from strains previously described.

Chancroid↗
PubMed1991

Molecular characterization of Haemophilus ducreyi by ribosomal DNA fingerprinting.

Intraspecies genotypic heterogeneity among Haemophilus ducreyi isolates was examined by using genomic fingerprints with rRNA from Escherichia coli as a probe. DNA from 44 isolates of H. ducreyi was digested by restriction endonuclease HincII or HindIII, separated by agarose gel electrophoresis, transferred to nylon membranes, and hybridized with 32P-labeled 16S and 23S rRNA. HincII digests yielded four hybridization patterns (ribotypes), whereas HindIII digests yielded eight ribotypes. Four HincII and five HindIII ribotypes were observed among 14 H. ducreyi isolates collected within a period of 1 month in Kenya, where chancroid is endemic. In contrast, one HincII and two HindIII ribotypes were observed among 28 isolates collected during the Orange County, Calif., chancroid epidemic that occurred in 1981 and 1982. The plasmid content, in conjunction with ribotyping, provided additional differentiation among some isolates of H. ducreyi. This study demonstrates that ribotyping of H. ducreyi may be used to study the epidemiology of chancroid.

Bacterial Typing Techniques↗
PubMed1990

National surveillance of antimicrobial resistance in Neisseria gonorrhoeae. The Gonococcal Isolate Surveillance Project.

The Gonococcal Isolate Surveillance Project is a national sentinel surveillance system to estimate levels and monitor trends of antimicrobial resistance in prospectively collected isolates of Neisseria gonorrhoeae. Of 6204 isolates evaluated from 21 clinic sites between September 1987 and December 1988, 21% met at least one of the surveillance criteria for resistance to penicillin, tetracycline, cefoxitin, or spectinomycin; 2.2% were penicillinase-producing N gonorrhoeae; 1.0% had high-level plasmid-mediated tetracycline resistance; and 16.8% of the isolates without plasmid-mediated resistance had chromosomally mediated resistance (defined as a minimum inhibitory concentration greater than or equal to 2 micrograms/mL) to penicillin, tetracycline, or cefoxitin. Three isolates were resistant to spectinomycin. All isolates were susceptible to ceftriaxone. Resistant isolates were identified from all participating centers. Patient demographic and behavioral characteristics were not predictive of infections caused by resistant organisms. These results demonstrate the wide distribution of antimicrobial-resistant N gonorrhoeae and support recent changes in Centers for Disease Control therapy recommendations for gonococcal infections that no longer recommend tetracycline and penicillin as first-line therapies.

Adolescent↗
PubMed1990

Current status of serotyping of Neisseria gonorrhoeae.

Protein I has become the basis of serotyping of N. gonorrhoeae. A panel of 12 anti-protein I monoclonal antibodies is supplied by Syva Company, Palo Alto, CA, through distributors for research purposes only. These distributors are responsible for storing the monoclonal antibodies, supplying research groups and training new users, particularly in the interpretation of coagglutination reactions. A European Workshop was held in Heidelberg, Federal Republic of Germany in July 1988 to discuss serotyping with these antibodies. The current uses of serotyping of N. gonorrhoeae include epidemiological studies, clinical purposes and surveillance of antibiotic resistance and plasmid carriage. Predominant serovars may be subtyped either by additional antibodies or with the use of another technique, such as auxotyping, determination of antibiotic sensitivities, plasmid analysis or genetic fingerprinting. Conversely, there is growing evidence that it may be appropriate to group certain serovars together. Data collected during prevalence studies could be combined with clinical information and an international data bank set up. This supposes a close future collaboration of all groups involved in the epidemiology of N. gonorrhoeae.

Antibodies, Monoclonal↗