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Resistance trends of Neisseria gonorrhoeae in the Republic of Korea.

Penicillinase-producing Neisseria gonorrhoeae has increased in the Far East to the point that penicillin can no longer be recommended as the drug of choice, mandating a change to spectinomycin. As part of an ongoing surveillance of antibiotic susceptibilities, minimal inhibitory concentrations of penicillin, tetracycline, spectinomycin, trimethoprim-sulfamethoxazole, cefoxitin, ceftriaxone, cefotaxime, and moxalactam were determined. A disturbing, steady increase in resistance to spectinomycin was documented.

Anti-Bacterial Agents↗

Acquisition by a Campylobacter-like strain of aphA-1, a kanamycin resistance determinant from members of the family Enterobacteriaceae.

A Campylobacter-like organism, BM2196, resistant to kanamycin and streptomycin-spectinomycin was isolated from the feces of a patient with acute enteritis. The kanamycin and streptomycin-spectinomycin resistances were not transferable to Camplylobacter sp. or to Escherichia coli, and no plasmid DNA was detected in this strain. The resistance genes were therefore tentatively assigned to a chromosomal locality. Analysis by the phosphocellulose paper-binding assay of extracts from BM2196 indicated that resistance to kanamycin and structurally related antibiotics was due to the synthesis of 3'-aminoglycoside phosphotransferase type I [APH(3')-I], an enzyme specific for gram-negative bacteria, and that resistance to streptomycin-spectinomycin was secondary to the presence of a 3",9-aminoglycoside adenylyltransferase. Homology between BM2196 and an APH(3')-I probe was detected by DNA-DNA hybridization. A 2.2-kilobase BM2196 DNA fragment conferring resistance to kanamycin was cloned in E. coli and was sequenced partially. The resistance gene appeared nearly identical to that of Tn903 from E. coli and was adjacent to IS15-delta, an insertion sequence widespread in gram-negative bacteria, thus indicating that Campylobacter species can act as a recipient for genes originating in members of the family Enterobacteriaceae.

Base Composition↗

Ribosomal proteins involved in the suppression of streptomycin dependence in Escherichia coli.

Suppression of streptomycin dependence in Escherichia coli strain K-114, a spectinomycin-sensitive strain, is correlated with modification of 30S ribosomal protein P4, the component modified in spectinomycin-resistant mutants. The mutant is unusual in that reversion from dependence has previously been correlated only with modification in 30S protein P4a. Introduction into K-114 of another mutation conferring spectinomycin resistance results in a further alteration in protein P4.

Amino Acids↗

Sensitivity of Neisseria gonorrhoeae to antibiotics in London (1976-78).

Three surveys of the sensitivity of pretreatment isolates of gonococci to penicillin, ampicillin, tetracycline, spectinomycin, streptomycin, and co-trimoxazole were carried out during the period 1976-78. Compared with the results of previous surveys in the London area the decline in the proportion of strains of gonococci which are insensitive to penicillin appears to have halted. No changes were found in the levels of resistance to ampicillin, tetracycline, or spectinomycin during the period surveyed, although there was a slight increase in the proportion of strains requiring concentrations of 20 microgram spectinomycin per ml for inhibition. Streptomycin resistance has decreased considerably and 91% of strains are now sensitive to 10 microgram streptomycin per ml.

Ampicillin↗

Antibiotic resistant N. gonorrhoeae in Trinidad and Tobago.

We tested the susceptibility patterns of 128 N. gonorrhoeae isolates to six antimicrobials; penicillin, tetracycline, spectinomycin, ceftriaxone, ciprofloxacin and azithromycin, and examined whether certain demographic or behavioral factors related to antibiotic use increased the likelihood of infection by a resistant strain. There was a low rate of resistance to penicillin; penicillinase-producing and chromosomal-mediated penicillin resistant gonorrhea were estimated to be 0.8%. A much higher proportion of isolates were resistant to tetracycline (up to 15%). All isolates were sensitive to spectinomycin, ciprofloxacin and ceftriaxone. However, less than 2% of isolates displayed intermediate resistance to both ciprofloxacin and ceftriaxone, and 9% exhibited intermediate resistance to spectinomycin. Patients who had obtained medication before attending the clinic and had taken all of the medication were more likely (p = 0.03) to be infected with a resistant strain of gonococcus. Also, patients who were asked by a clinic doctor to return for a test of cure during an earlier clinic visit, but who did not return were more likely to be infected with a resistant organism (p = 0.006) compared to those who returned at the doctor's request. These findings have important implications for antibiotic use and educational programs in Trinidad and Tobago.

Adolescent↗

In vitro activity of several antimicrobial agents against genital mycoplasmas.

The increasing resistance of genital mycoplasmas to tetracyclines is a serious problem, since this group of antibiotics is one of the few that is effective against virtually all species of mycoplasmas. Tetracyclines are also used to treat many sexually transmitted diseases. In this study, we assessed the susceptibility of Mycoplasma hominis and Ureaplasma urealyticum to macrolides, tetracyclines, spectinomycin, and trospectomycin by the agar dilution method. For M hominis, trospectomycin was the most active agent. Spectinomycin, tetracycline, and doxycycline had comparable mycoplasmatic activity, and the macrolides were ineffective. Against U urealyticum, spectinomycin and trospectomycin were the most active drugs, and were at least twofold more active than the macrolides and tetracyclines.

Anti-Bacterial Agents↗

Cross-Canada survey of susceptibility of Neisseria gonorrhoeae isolates to six antimicrobial agents.

The minimum inhibitory concentrations (MIC's) of penicillin, ampicillin, tetracycline, erythromycin, spectinomycin and sulfadiazine were determined for 732 isolates of Neisseria gonorrhoeae collected in 1973-74. Comparison of the results of this survey with data from other Canadian studies showed that the percentage of isolates resistant to tetracycline had not changed since 1966, but that the percentage of erythromycin-resistant isolates had decreased. After an initial increase in 1966 the percentage of penicillin-resistant isolates stabilized. Spectinomycin-resistant isolates were not found. Positive correlations were observed between the MICs of the antibiotics tested; the highest positive correlations were between penicillin and ampicillin and between penicillin and tetracycline. A positive correlation was also noted between penicillin resistance and increasing spectinomycin MICs. Finally, a significant seasonal variation in MICs was found, the trend being towards increasing MICs during the summer.

Anti-Bacterial Agents↗

Antibiotic susceptibility of Neisseria gonorrhoeae isolated in Johannesburg.

The susceptibility of 175 clinical isolates of Neisseria gonorrhoeae to penicillin G, ampicillin, erythromycin, tetracycline and spectinomycin was determined. Almost one-fifth of strains were relatively resistant to penicillin G. Relative resistance to penicillin G was significantly correlated with resistance to ampicillin, tetracycline and erythromycin, but not with resistance to spectinomycin. No penicillinase-producing or spectinomycin-resistant strains were encountered in this study. The relevance of the findings to the management of gonococcal urethritis is discussed.

Ampicillin↗

[Isolation and characteristics of the biological and genetic properties of neamin-resistant mutants of Salmonella typhimurium and Salmonella dublin candidates for vaccine creation].

Mutants, resistant to neamine and spectinomycin, have been isolated from S. typhimurium and S. dublin highly virulent strains. The neamine-resistant mutants can be divided into 3 classes in accordance with their sensitivity to streptomycin: sensitive, resistant to low and high concentrations of this antibiotic. The transduction analysis with the use of bacteriophage P 22 has revealed that the spectinomycin-resistant mutations under study are spc A mutations, while the mutations leading to resistance to neamine in class Near Strr 500 are nea B mutations. The mutation leading to resistance to spectinomycin (spc A) has been found to produce no changes in the virulence of salmonellae in the intraperitoneal infection of mice. The mutations leading to resistance to neamine and streptomycin (nea B and str A) have been found to decrease virulence.

Animals↗

Susceptibility of Neisseria gonorrhoeae isolates from Jakarta, Indonesia, to antibiotics.

The minimum inhibitory concentration (MIC) of penicillin, tetracycline and spectinomycin was determined for 6 beta-lactamase (PPNG) and 73 non beta-lactamase producing Neisseria gonorrhoeae isolates from Jakarta, Indonesia. All PPNG were resistant to greater than or equal to 128 micrograms/ml penicillin. Forty-six percent of the non-PPNG strains were inhibited by less than or equal to 1.0 microgram/ml of penicillin and 97% by less than or equal to 4 micrograms/ml. Most of the PPNG and non-PPNG isolates (90%) were inhibited by less than or equal to 4 micrograms/ml tetracycline and less than or equal to 16 micrograms/ml spectinomycin. Two non-PPNG strains were resistant to 64 micrograms/ml of tetracycline, 8 micrograms/ml penicillin and 32 micrograms/ml spectinomycin. The non-PPNG strains generally were more resistant to penicillin and tetracycline compared to strains tested from other parts of the world in previously reported studies.

Anti-Bacterial Agents↗

Chloroplast transformation in plants: polyethylene glycol (PEG) treatment of protoplasts is an alternative to biolistic delivery systems.

Nicotiana plumbaginifolia protoplasts were directly transformed by PEG treatment with a cloned 16S rRNA gene isolated from a double antibiotic-resistant Nicotiana tabacum plastid mutant. Putative plastid transformants were selected in cell culture by their spectinomycin resistance and identified by their unselected streptomycin resistance. Alternatively, cell lines were selected in the presence of both antibiotics. The cell line (and its regenerated plants) selected solely for spectinomycin resistance demonstrated an extensive segregation of streptomycin resistance in subsequent tests, while the double-selected line showed stable resistance for both antibiotics. The resistance markers were inherited maternally. In the putative plastid transformants the origin of the resistance mutations was identified by the absence of an AatII site, missing in the donor N. tabacum plastid gene (spectinomycin resistance site) but present in that of wild-type N. plumbaginifolia, and a sequence analysis of the particular nucleotide changes in both resistance sites. Restriction enzyme analysis of total plastid DNA (ptDNA), and the recloning and full sequencing of the fragment introduced, investigated in one of the plastid transformants, showed no DNA rearrangements accompanied with the integration process. Sequence analysis indicated a targeted, homologous integration of the DNA fragment introduced but an unexpectedly complete homology of the parental ptDNA sequences in this region prevented the location of borders. Although the frequency of plastid transformant colonies (2 x 10(-5)) should still be improved, this method for stable chloroplast DNA transformation is comparable with or more efficient than the particle bombardment techniques.

Base Sequence↗

Treatment of gonorrhea in pregnancy.

OBJECTIVE: To evaluate prospectively the 1989 Centers for Disease Control recommendations for treatment of gonorrhea in pregnancy. METHODS: Two hundred fifty-two women referred with probable endocervical gonorrhea had pre-treatment endocervical, rectal, and oral cultures for Neisseria gonorrhoeae and direct fluorescent antibody testing for Chlamydia trachomatis. They were assigned randomly to receive ceftriaxone 250 mg intramuscularly (IM), spectinomycin 2 g IM, or amoxicillin 3 g orally plus probenecid 1 g orally. Treatment was unblinded and in a 1:1:1 distribution. RESULTS: Two hundred forty-five women (97%) had endocervical infection, 68 (27%) had rectal infection, and 17 (7%) had pharyngeal infection. One hundred two of 252 women (40%) had concomitant endocervical C trachomatis. The overall efficacy was 235 of 252 subjects (93%) (95% confidence interval [CI] 90.1-96.4%). Ceftriaxone was effective in 80 of 84 cases (95%) (95% CI 90.6-99.9%), amoxicillin with probenecid was effective in 75 of 84 cases (89%) (95% CI 82.5-96%), and spectinomycin was effective in 80 of 84 cases (95%) (95% CI 90.6-99.9%). No significant difference was noted in overall efficacy or by site of infection. There was no increased incidence of congenital malformations in the offspring spring of any treatment group. CONCLUSIONS: Ceftriaxone and spectinomycin are safe and effective for the treatment of gonorrhea in pregnancy. Amoxicillin with probenecid has lower efficacy and is not recommended for treatment of gonococcal infection in pregnancy.

Adult↗

Multi-residue confirmation of aminoglycoside antibiotics and bovine kidney by ion spray high-performance liquid chromatography/tandem mass spectrometry.

An ion spray high-performance liquid chromatographic/tandem mass spectrometric (HPLC/MS/MS) method capable of determining the following six aminoglycosides in bovine kidney is presented: spectinomycin, hygromycin B, streptomycin, dihydrostreptomycin, gentamicin C complex and neomycin B. Tobramycin was used as an internal standard. This method uses an improved matrix solid-phase dispersion (MSPD) method for tissue extraction. A gradient HPLC separation was developed with mobile phases consisting of aqueous 20 mM pentafluoropropionic acid and acetonitrile. Protonated molecules served as precursor ions for collision-induced dissociation (CID) and three product ions were chosen for each analyte for selected reaction monitoring (SRM) where possible. A validation study was conducted for the confirmation of dihydrostreptomycin, neomycin B and four major components of the gentamicin C complex through SRM HPLC/MS/MS analysis of negative control, fortified and incurred bovine kidney samples. All of the samples analyzed could be confirmed with ion ratios within 15% of the daily mean of fortified standards and 90% of the samples had ion ratios within 10%. All compounds except spectinomycin could be detected (while monitoring three ions by SRM) in bovine kidney tissue at or below the regulatory level of concern. MSPD recoveries were acceptable with the exception of the 27% value observed for spectinomycin.

Aminoglycosides↗

Mutations of non-canonical base-pairs in the 3' major domain of Escherichia coli 16 S ribosomal RNA affect the initiation and elongation of protein synthesis.

Three single-point mutations and two multibase substitutions were introduced into the lower half of the 3' major domain of Escherichia coli 16 S ribosomal RNA. The three single mutations were located in helix 29 (U1341C) or in helix 43 (U1351C or A1357C) and replaced highly conserved non-canonical base-pairs with Watson-Crick base-pairs. The two multibase substitutions were located at the base of helix 42, where they transformed an irregular portion into a Watson-Crick [correction of Waston-Crick] segment. Each of the single mutations could be expressed in vivo from the rrnB operon of a multicopy plasmid under control of constitutive promoters, and none of them affected growth-rate. However, mutation A1357C, but not U1341C or U1351C, severely retarded cell growth, when expressed together with another mutation in the upper half of the 3' major domain, C1192U. The latter mutation is located in helix 34 and abolishes the binding of spectinomycin, a protein synthesis inhibitor. The proportion of mutated ribosomes was high in polysomes, suggesting that the A1357C and C1192U double mutation did not affect the initiation but rather the elongation of protein synthesis. The effect of the double mutation reveals a functional interplay between helices 34 and 43. Furthermore, an interaction between helices 34 and 43 was also suggested by studies of protection by spectinomycin against chemical attack, that showed that the binding site of spectinomycin was restored with ribosomes bearing another double mutation, U1351C and C1192U. In contrast to the single mutations, the multiple mutations in helix 42 could not be expressed in vivo under control of the strong constitutive promoters, but could be expressed under control of the weaker, thermoinducible lambda PL promoter. They did not affect cell growth, whether expressed in the absence or the presence of the C1192U mutation. However, under conditions where protein synthesis depended exclusively on ribosomes with plasmid-encoded rRNA, cells transformed with plasmids altered in helix 42 could not grow. Analysis of the plasmid-borne 16 S rRNA distribution in bacteria transformed with these mutant plasmids showed that mutant 16 S rRNA was present in a high proportion in the free 30 S subunits but was underrepresented in 70 S ribosomes and polysomes. Extension inhibition assays (toeprinting) demonstrated that this altered distribution resulted from an impaired capacity of the mutant 30 S subunits to form translation initiation complexes.

Bacterial Proteins↗

Isolation and characterization of DNA-binding mutants of a plasmid replication initiation protein utilizing an in vivo binding assay.

An in vivo screen was developed for the identification of mutants of the RK2 replication initiation protein, TrfA, that were altered in their binding to the iterons within the plasmid RK2 origin of replication. This assay is based on an antibiotic selection system originally described by Elledge, Sugiono, Guarente, and Davis (Proc. Natl. Acad. Sci. USA86, 3689-3693, 1989) for the isolation in vivo of genes encoding sequence-specific DNA-binding proteins. A TrfA-specific binding site consisting of two 17-bp iterons separated by a nonrandom 6-bp spacer was placed 3' to a strong constitutive promoter. This promoter-iteron fragment was then inserted into the assay vector convergent to the aadA gene such that an increased level of spectinomycin resistance by the Escherichia coli host was dependent on the binding of wild-type TrfA protein to the binding site. The in vivo system was used to specifically isolate TrfA mutants which were either defective in binding or capable of effecting increased levels of spectinomycin resistance as compared to wild-type TrfA. The defective TrfA mutants isolated by this screen were purified and found to be considerably less effective in DNA binding by in vitro gel mobility shift assays. The map location was determined for these six defective TrfA mutants. Each of the mutations consisted of a single base change and mapped within codons extending over a 162 amino acid sequence. All of the mutants which were capable of effecting increased levels of spectinomycin resistance in the in vivo DNA-binding assay also showed some alteration in RK2 replication in vivo with most of the mutants having a copy-up phenotype similar to previously isolated TrfA mutants able to maintain an eight-iteron RK2 origin plasmid at a higher copy number.

Amino Acid Sequence↗

Isolation and characterization of deletion derivatives of pDL282, an Actinobacillus actinomycetemcomitans/Escherichia coli shuttle plasmid.

Recent reports have described the construction of several shuttle plasmids (D.J. LeBlanc, L. L. Lee, A. Al-Jaibat, P. K. Sreenivasan, and P. M. Fives-Taylor, Oral Micro. Immunol. (1993) 8, 94-99) and the development of an efficient transformation system for Actinobacillus actinomycetemcomitans (P. K. Sreenivasan, D. J. LeBlanc, L. L. Lee, and P. M. Fives-Taylor, Infect. Immun. (1991) 59, 4621-4627), a gram-negative bacterium implicated in human periodontal disease. This report presents results from further studies on pDL282, an A. actinomycetemcomitans-Escherichia coli shuttle plasmid. A. actinomycetemcomitans containing pDL282 lost the plasmid at a rapid rate when cultured in antibiotic free medium. Intact pDL282 was maintained for 20 generations or more when the host cells were grown in the presence of ampicillin, or ampicillin plus spectinomycin. However, prolonged incubation in the presence of spectinomycin only resulted in the emergence of one or the other of two unique deletion derivatives of pDL282, designated pPK1 and pPK2. Whereas A. actinomycetemcomitans was efficiently transformed with pDL282 (5.7 kb), pPK1 (3.6 kb), and pPK2 (2.5 kb), E. coli was transformed only by the two largest species. Like the parent molecule, pPK1 and pPK2 were rapidly lost from A. actinomycetemcomitans hosts in the absence of antibiotic selection. Neither pPK1 nor pPK2 suffered any further deletions following prolonged cultivation in the presence of spectinomycin. The minimal replicon of pVT736-1, the A. actinomycetemcomitans-derived plasmid component of pDL282, was located within a 1400 bp DNA fragment of pPK1 and pPK2.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus↗

Deamplification and deletion of amplified DNA in Streptomyces lividans and S. fradiae.

Streptomyces lividans arginine auxotrophs which show amplification of a 5.7-kb DNA sequence, arose at a very high frequency, varying from 10% to 25% of Cmls spores. The amplifiable DNA sequence was shown to be stable over many generations. However, treatment of Cmls arg mutants with subinhibitory concentrations of antibiotics such as spectinomycin, streptomycin, chloramphenicol, thiostrepton and kanamycin, either during sporulation or during vegetative growth of mycelia, led to the deletion of the entire amplified DNA sequence, including the left and right junction sequences. Depending upon the method of antibiotic treatment a reduction in the copy number of the amplified DNA was also observed. This reduction in copy number apparently occurred without drastically affecting the basic structure of the amplifiable unit of DNA. This phenomenon appears to be universal since deamplification and deletion were observed also in S. fradiae. Further, spontaneous arg mutants arose at much lower frequency from spectinomycin-pretreated Cmls cells compared to untreated cells. These arg mutants isolated in the presence of spectinomycin did not show amplification of the 5.7-kb sequence. Southern blot analysis using the 5.7-kb probe showed that the entire DNA sequence homologous to the amplifiable DNA sequence had been deleted.

Chromosome Deletion↗

[Antibiotic susceptibility of Neisseria gonorrhoeae isolates in Berlin].

BACKGROUND AND OBJECTIVE: Because of the increasing resistance of Neisseria gonorrhoeae, we studied the actual resistance of isolates in Berlin. PATIENTS/METHODS: 85 Neisseria gonorrhoeae isolates were collected between 1995 and 1997. Susceptibility testing was performed for penicillin G, tetracycline, spectinomycin, ceftriaxone, ciprofloxacin and azithromycin by agar dilution. RESULTS: 18.8% isolates were resistant or intermediately resistant to penicillin G (including 6 PPNG). 12.9% isolates were resistant, 43.5% intermediately resistant to tetracycline. One strain was resistant against ciprofloxacin, 4 isolates showed increased MIC values (0.06-0.5 mg/l), whereas 78 isolates were fully susceptible (< 0.007 mg/l). All isolates were susceptible to spectinomycin, ceftriaxone, and azithromycin. CONCLUSIONS: Penicillin G and tetracycline should be given only in cases of proven sensibility. Resistance against ciprofloxacin may occur, especially in isolates acquired in south-east Asia. Ceftriaxone, spectinomycin and azithromycin were active against all isolates. The actual resistance situation should be monitored.

Anti-Bacterial Agents↗