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PubMed1987

Antibiotic sensitivity and mutation rates to antibiotic resistance in Mycoplasma mycoides ssp. mycoides.

The antibiotic resistance of Mycoplasma mycoides ssp. mycoides strain T1 was investigated. This strain was resistant to high levels (greater than 100 micrograms ml-1) of rifampicin and nalidixic acid. It was sensitive to streptomycin, spectinomycin and novobiocin; however, single step mutants with high levels of resistance (greater than 100 micrograms ml-1) were readily isolated. With erythromycin and tylosin for which the minimum inhibitory concentration (MIC) for the parent strain was less than 0.1 microgram ml-1, mutants resistant to greater than 100 micrograms ml-1 were obtained in two and three steps respectively. The MIC of tetracycline in single step resistant mutants (0.6 microgram ml-1) was tenfold higher than the parent strain, but could not be increased further. There was only a twofold increase in resistance to chloramphenicol in single step mutants. The frequency of resistant mutants varied with the antibiotic and was between 4 X 10(-6) and 2 X 10(-8). The mutation rate to antibiotic resistance to streptomycin, spectinomycin, novobiocin, erythromycin and tylosin was between 3 X 10(-8) and 5 X 10(-9) per cell per generation. There was a fivefold decrease in mutation rate to resistance to 60 micrograms ml-1 streptomycin compared to that to 20 micrograms ml-1.

Anti-Bacterial Agents↗
PubMed2006

Characterization of the bifunctional aminoglycoside-modifying enzyme ANT(3'')-Ii/AAC(6')-IId from Serratia marcescens.

A newly discovered bifunctional antibiotic resistance enzyme from Serratia marcescens catalyzes adenylation and acetylation of aminoglycoside antibiotics. The structure assignment of the enzymic products indicated that acetylation takes place on the 6'-amine of kanamycin A and the adenylation on 3''- and 9-hydroxyl groups of streptomycin and spectinomycin, respectively. The adenyltransferase domain appears to be highly specific to spectinomycin and streptomycin, while the acetyltransferase domain shows a broad substrate profile. Initial velocity patterns indicate that both domains follow a sequential kinetic mechanism. The use of dead-end and product inhibition, the solvent isotope effect, and the solvent viscosity effect reveals that the adenyltransferase domain catalyzes the reaction by a Theorell-Chance kinetic mechanism, where ATP binds to the enzyme prior to the aminoglycoside and the modified antibiotic is the last product to be released. The acetyltransferase domain follows an ordered bi-bi kinetic mechanism, in which the antibiotic is the first substrate that binds to the active site and CoASH is released prior to the modified aminoglycoside. The merging of two genes to create bifunctional resistance enzymes with expanded profiles has now been documented in four instances, including the subject of study in this report, which suggests a new trend in the emergence of resistance to aminoglycoside antibiotics among pathogens.

Acetylation↗
PubMed2002

Comparative in vitro activity of 16 antimicrobial agents against Actinobacillus pleuropneumoniae.

Sixteen antimicrobial agents were tested for their activity against 68 isolates of Actinobacillus pleuropneumoniae by determining the minimum inhibitory concentrations (MICs). Ceftiofur and the fluoroquinolones danofloxacin and enrofloxacin were the most active compounds, with a MIC for 90% of the isolates (MIC90) of (0.05 microg/ml. The MIC90 values of benzylpenicillin, amoxicillin and aspoxicillin were 0.78 units/ml, 0.39 microg/ml and < or = 0.05 microg/ml, respectively. Three isolates (4.4%) were resistant to penicillins, but aspoxicillin was as active as ceftiofur against the susceptible isolates, with MICs of < or = 0.05 microg/ml for all isolates. Resistance to oxytetracycline, chloramphenicol and thiamphenicol occurred in 22 (32.4%), 14 (20.6%) and 15 (22.1%) of the isolates, respectively. Doxycycline was more active than oxytetracycline, with a MIC90 of 1.56 microg/ml as against 25 microg/ml. Florfenicol was not only as active as thiamphenicol, with a MIC for 50% of the isolates (MIC50) of 0.39 microg/ml, but also active against thiamphenicol-resistant isolates. All the isolates were susceptible to florfenicol. All the isolates were also susceptible to gentamicin, spectinomycin, tilmicosin, colistin and tiamulin. Of these, spectinomycin was the least active, with a MIC50 of 25 microg/ml, followed by tiamulin, with a MIC50 of 6.25 microg/ml. Of the 68 isolates tested, 49 (72.0%) were of serotype 2; 14 (20.5%) were of serotype 1; 2 each (3.0%) were of serotypes 5 and 6; and one was of serotype 7. Of the isolates, 23 (33.8%) were resistant to one or more of the major antibiotics. Antibiotic resistance was found only infrequently among serotype 2, with 5 (10.2%) of 49 isolates being resistant to chloramphenicol and/or oxytetracycline, while it occurred in 18 (94.7%) of the 19 isolates of other serotypes.

Actinobacillus pleuropneumoniae↗
PubMed1992

The structure of ribosomal protein S5 reveals sites of interaction with 16S rRNA.

Understanding the process whereby the ribosome translates the genetic code into protein molecules will ultimately require high-resolution structural information, and we report here the first crystal structure of a protein from the small ribosomal subunit. This protein, S5, has a molecular mass of 17,500 and is highly conserved in all lifeforms. The molecule contains two distinct alpha/beta domains that have structural similarities to several other proteins that are components of ribonucleoprotein complexes. Mutations in S5 result in several phenotypes which suggest that S5 may have a role in translational fidelity and translocation. These include ribosome ambiguity or ram, reversion from streptomycin dependence and resistance to spectinomycin. Also, a cold-sensitive, spectinomycin-resistant mutant of S5 has been identified which is defective in initiation. Here we show that these mutations map to two distinct regions of the molecule which seem to be sites of interaction with ribosomal RNA. A structure/function analysis of the molecule reveals discrepancies with current models of the 30S subunit.

Amino Acid Sequence↗
PubMed1985

A plasmid for diffusible pigment production in Staphylococcus aureus.

Production of diffusible pigment in a strain of Staphylococcus aureus (WG260) has been associated with a plasmid of c.26 megadaltons which can be co-transduced with inducible erythromycin and spectinomycin resistance. However, the diffusible pigment plasmid can be lost from the transductants without loss of inducible erythromycin and spectinomycin resistance. The evidence suggests that the resistance determinants are located on an element similar or identical to transposon Tn554, and, during transduction of the diffusible pigment plasmid, a copy of the resistance determinants always inserts into the chromosome of the transductant. This is the first report of such an element occurring on a plasmid in a clinical isolate of S. aureus. To date, the diffusible pigment plasmid has been isolated only as the open-circular conformation of plasmid DNA and is probably a highly relaxable plasmid. The production of the orange, diffusible pigment was shown to be independent of colony pigmentation.

Chromosome Mapping↗
PubMed1999

Antibiotic resistance of Escherichia coli isolated from poultry workers, patients and chicken in the eastern province of Saudi Arabia.

The prevalence of antibiotic-resistant Escherichia coli isolates from faecal samples from 117 poultry industry workers, 100 patients and119 healthy chicken were compared. Resistance of E. coli chicken isolates to ampicillin, chloramphenicol, gentamicin, spectinomycin, tetracycline and trimethoprim + sulphamethoxazole (TMP + SMX) (range 57% - 99.1%) were significantly higher than those isolated from patients (range 21.9% - 71.4%) and workers (range 35% - 71.8%). However, for drugs not used in poultry, such as amoxicillin + cluvalanate (AMX + CLV), ceftazidime and nitrofurantoin, resistance rates of chicken isolates (range 0% - 2.6%) were significantly lower than those of patient isolates (range 8.7% - 30%). Resistance to spectinomycin reached 96% in E. coli chicken isolates and 71% in organisms isolated from humans. Use of this drug in Saudi Arabia is mostly limited to veterinary purposes. Multidrug resistance is alarmingly high in all groups but was highest in chicken isolates (77.4%). Serotyping of E. coli isolates showed that 27% of the organisms isolated from patients were overlapping with 10.9% of the chicken isolates, indicating the possibility of chicken being a source of the resistance pool for humans. We therefore call for the banning of antibiotics in the poultry industry as growth promoters and recommend that their use be restricted to treating infections.

Animals↗
PubMed1987

Specialized ribosome system: preferential translation of a single mRNA species by a subpopulation of mutated ribosomes in Escherichia coli.

In Escherichia coli, all mRNAs are translated by one pool of functionally identical ribosomes. Here, we describe a system in which a subpopulation of modified ribosomes are directed to a single mutated mRNA species. This was accomplished by changing the Shine-Dalgarno sequence that precedes the heterologous human growth hormone gene from 5' GGAGG to 5' CCTCC or 5' GTGTG. Translation of these modified mRNAs by wild-type ribosomes is very inefficient. When the anti-Shine-Dalgarno region (i.e., the region complementary to the Shine-Dalgarno sequence) at the 3' end of the gene encoding 16S rRNA (rrnB) was altered from 5' CCTCC to 5' GGAGG or 5' CACAC, thus restoring its potential to base-pair with the mutated human growth hormone mRNA, significant expression of this mRNA occurred. Growth hormone synthesis was dependent on induction of the mutated rrnB operon. Subsequently, these specialized ribosomes were made spectinomycin-resistant by the introduction of a C----U substitution at position 1192 of the 16S rRNA. Thus, host protein synthesis could be shut off by the addition of spectinomycin and the specificity and efficiency of the specialized ribosomes could be assessed. Since the specialized ribosomes represent a nonessential subpopulation in the cell, this system offers an approach to the study of mutations elsewhere in the 16S-rRNA gene that otherwise would be lethal to the cell.

Base Sequence↗
PubMed2004

Identification of a variant "Rome clone" of methicillin-resistant Staphylococcus aureus with decreased susceptibility to vancomycin, responsible for an outbreak in an intensive care unit.

We describe the identification of a variant of the "Rome clone" of methicillin-resistant Staphylococcus aureus (MRSA), responsible for an outbreak involving 5 patients in a Cardiac Surgery Intensive Care Unit (CS-ICU) of a tertiary-care University Hospital in Rome. All strains isolated from patients and from nasal swabs obtained from four members of the CS-ICU personnel, belonged to the same identified clone. The characteristics of this clone were: (1) resistance to ampicillin, oxacillin, gentamicin, ciprofloxacin, erythromycin, clindamycin, rifampin, spectinomycin, and tetracycline; (2) vancomycin and teicoplanin MICs respectively of 2 and 4 mg/L; (3) heteroresistant subpopulations in the presence of 4 and 6 mg/L of vancomycin (10(-3) and 10(-5), respectively); (4) clonal type I::J::C determined following an established protocol (mec A::Tn 554 ::PFGE); (5) sequence type ST247 (3-3-1-12-4-4-16), obtained by multilocus sequence typing (MLST); and (6) the staphylococcal cassette chromosome mec (SCC) IA, obtained by multiplex PCR method. This new strain had different characteristics from the epidemic clone circulating in the same hospital from 1997 and designed "Rome clone," which was susceptible to erythromycin, clindamycin, and spectinomycin and belonged to the II::NH::C genetic background. A high genetic similarity between this Rome clone and the previously classified Archaic and Iberian clones was found, because they shared the same allelic profile (ST247), probably originating from the same S. aureus ancestor of the Iberian MRSA strains. Therefore, the strains responsible for the outbreak, with vancomycin MICs 2-4 mg/L, are variant clones, showing the genotype of the "Rome clone," the ST247 in association with SCC mec type IA (ST247-MRSA-IA), and are characterized by a uniform susceptibility to fosfomycin.

Anti-Bacterial Agents↗
PubMed1998

Molecular epidemiology of antibiotic resistance genes in multiresistant epidemic Salmonella typhimurium DT 104.

The epidemiology of antibiotic resistance genes in epidemic multiresistant S. typhimurium DT 104 of human and animal origin was investigated. DNA prepared from 45 human and 21 animal strains isolated between 1984 and 1997, including eight isolated in other European countries, the USA, Trinidad, and South Africa and resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, spectinomycin, tetracyclines (R-type ACSSuSpT) were examined for the presence of integrons by PCR. Integron hot spots were observed in all strains conferring resistance to ACSSuSpT in two copies, determined by two discrete bands of approximately 1.0 and 1.2 kb. Direct nucleotide sequencing of the individual amplicons of selected strains indicated that the 1.0 kb gene product was ant (3")-Ia, responsible for resistance to streptomycin and spectinomycin; the 1.2 kb amplicon contained the gene blaPSE-1, encoding the beta-lactamase PSE-1 (CARB-2). Both integrons were encoded on a single XbaI macrorestriction fragment of approximately 10 kb. All isolates of DT 104 of this resistance phenotype contained the same inserted gene cassettes, irrespective of source and country of origin, supporting the suggestion of the spread of an epidemic clone. Sequence analysis of the quinolone resistance determining region (QRDR) of gyrA of 15 multiresistant strains conferring additional resistance to nalidixic acid and ciprofloxacin (R-type ACSSuSpTNxCp) identified two discrete base substitutions at codon Asp-87. Conversion of Asp-87 --> Asn was most commonly observed, in 7/10 human and 4/5 animal isolates, suggesting that this codon plays a major role in the development of ciprofloxacin resistance in multiresistant S. typhimurium DT 104.

Animals↗
PubMed1989

Antibiotic resistance mutations in the chloroplast 16S and 23S rRNA genes of Chlamydomonas reinhardtii: correlation of genetic and physical maps of the chloroplast genome.

Mutants resistant to streptomycin, spectinomycin, neamine/kanamycin and erythromycin define eight genetic loci in a linear linkage group corresponding to about 21 kb of the circular chloroplast genome of Chlamydomonas reinhardtii. With one exception, all of these mutants represent single base-pair changes in conserved regions of the genes encoding the 16S and 23S chloroplast ribosomal RNAs. Streptomycin resistance can result from changes at the bases equivalent to Escherichia coli 13, 523, and 912-915 in the 16S gene, or from mutations in the rps12 gene encoding chloroplast ribosomal protein S12. In the 912-915 region of the 16S gene, three mutations were identified that resulted in different levels of streptomycin resistance in vitro. Although the three regions of the 16S rRNA mutable to streptomycin resistance are widely separated in the primary sequence, studies by other laboratories of RNA secondary structure and protein cross-linking suggest that all three regions are involved in a common ribosomal neighborhood that interacts with ribosomal proteins S4, S5 and S12. Three different changes within a conserved region of the 16S gene, equivalent to E. coli bases 1191-1193, confer varying levels of spectinomycin resistance, while resistance to neamine and kanamycin results from mutations in the 16S gene at bases equivalent to E. coli 1408 and 1409. Five mutations in two genetically distinct erythromycin resistance loci map in the 23S rDNA of C. reinhardtii, at positions equivalent to E. coli 2057-2058 and 2611, corresponding to the rib3 and rib2 loci of yeast mitochondria respectively. Although all five mutants are highly resistant to erythromycin, they differ in levels of cross-resistance to lincomycin and clindamycin. The order and spacing of all these mutations in the physical map are entirely consistent with our genetic map of the same loci and thereby validate the zygote clone method of analysis used to generate this map. These results are discussed in comparison with other published maps of chloroplast genes based on analysis by different methods using many of the same mutants.

Base Sequence↗
PubMed1994

Incubating syphilis in patients treated for gonorrhea: a comparison of treatment regimens.

Dade County sexually transmitted disease clinic records were reviewed to estimate the relative effectiveness of gonorrhea treatment regimens for eradicating incubating syphilis. Records were searched to see if persons treated for gonorrhea returned with primary syphilis 3-45 days after treatment or secondary syphilis 15-90 days after treatment. The number of persons treated was adjusted for the prevalence of syphilis in the year of treatment. Between 1985 and 1992, 98,441 persons were treated for gonorrhea. Syphilis was diagnosed in an interval that suggested it was incubating at the time of the treatment for 5.6/10(4) (adjusted number) persons treated with spectinomycin alone (a regimen not expected to eradicate syphilis); 2.9/10(4) persons treated with spectinomycin plus tetracycline, doxycycline, or erythromycin; and 2.1/10(4) persons treated with ceftriaxone plus tetracycline, doxycycline, or erythromycin (P > .1). Incubating syphilis was rare despite a syphilis epidemic. The effectiveness of a regimen for eradicating incubating syphilis should not be a major consideration when choosing gonorrhea therapy.

Ceftriaxone↗
PubMed1986

Transposable resistance to trimethoprim and 0/129 in Vibrio cholerae.

Vibrio cholerae biotype el tor strain BM2508, resistant to trimethoprim, 0/129, streptomycin and spectinomycin was isolated from the faeces of a child with severe diarrhoea. Resistance to trimethoprim and 0/129 was due to a dihydrofolate reductase type I and resistance to streptomycin-spectinomycin to a 3'',9-aminoglycoside-aminocyclitol adenylyltransferase. The resistance genes were not transferable to Escherichia coli and, as inferred from ultracentrifugation in cesium chloride-ethidium bromide and agarose gel electrophoresis of crude bacterial lysates, were located on the chromosome. The resistance genes were transposed to multiple sites of plasmids belonging to incompatibility groups 6-C and P, introduced in BM2508 and were subsequently transferred to E. coli (rec-), Salmonella typhimurium, V. cholerae and V. parahaemolyticus strains where they re-transposed into the chromosome. Analysis of plasmid DNA from the transconjugants by agarose gel electrophoresis following digestion with HindIII and by Southern hybridization using a ColEl::Tn7 probe indicated the presence of a 14-kilobase transposon, Tn1527, closely related to Tn7. The emergence of Tn1527 in V. cholerae may lead to prophylactic and therapeutic failures due to trimethoprim resistance and to bacterial misidentification because of cross resistance to 0/129.

Anti-Bacterial Agents↗
PubMed2001

Evolution in the trends of antimicrobial resistance in Neisseria gonorrhoeae isolated in Durban over a 5 year period: impact of the introduction of syndromic management.

Antimicrobial susceptibility testing was performed on isolates of Neisseria gonorrhoeae obtained from patients attending the City Health STD clinic in Durban, KwaZuluNatal, using the following drugs: penicillin, tetracycline, ciprofloxacin, ofloxacin, ceftriaxone, spectinomycin, erythromycin and azithromycin. These isolates were collected over a 6 year period from 1995 to 2000. Four hundred and fifteen strains were tested: 61 in 1995, 198 in 1997, 98 in 1998/99 and 58 in 1999/2000. A shift to the right is observed in the susceptibilities of N. gonorrhoeae to the currently recommended drugs in the syndromic management guidelines viz. penicillin, tetracycline, ceftriaxone, ciprofloxacin, spectinomycin and erythromycin. The prevalence of penicillinase-producing N. gonorrhoeae is currently c. 30%, whereas that of plasmid-mediated tetracycline-resistant N. gonorrhoeae is c. 50%. There is a definite association between the MICs of strains falling within the penicillin and tetracycline chromosomally resistant group, and strains exhibiting a decreased susceptibility to ciprofloxacin and ceftriaxone. The MICs of azithromycin showed a similar distribution when compared with erythromycin for 1999/2000 isolates. We postulate that the presence of efflux pumps might play a role in the increasing MICs that we observe among structurally unrelated groups of drugs. Furthermore, widespread use of these antimicrobials in the community may offer a selective advantage to the development of resistance. The implications of this are far reaching and the local susceptibility trends of N. gonorrhoeae need to be monitored constantly to direct therapy.

Anti-Bacterial Agents↗
PubMed2006

Antimicrobial susceptibility of Neisseria gonorrhoeae in Greece: data for the years 1994-2004.

OBJECTIVES: Surveillance data concerning antimicrobial susceptibilities of Neisseria gonorrhoeae isolated in Greece during the 11 year period 1994-2004 are presented. METHODS: Antimicrobial susceptibilities of all gonococcal isolates received by the Greek National Reference Center for N. gonorrhoeae during the study period were determined in terms of MICs using Etest. Trends in yearly isolation frequencies by susceptibility category were estimated for defining significant changes in overall susceptibility figures. RESULTS: Cefotaxime and spectinomycin retained undiminished activity against all isolates throughout the study period. High rates of resistance and intermediate susceptibilities were noticed for penicillin, tetracycline and erythromycin, and even for norfloxacin and ciprofloxacin. A substantial portion (16.5%) of the gonococcal samples consisted of multiresistant strains exhibiting resistance to two or more agents of different antibiotic classes. Although annual rates of low-level chromosomal resistance decreased, high-level resistance owing to the presence of penicillin- and tetracycline-resistance plasmids increased. Fluoroquinolone resistance also showed a significant increasing trend after 1996, reaching a peak rate of 11.3% in 2004. CONCLUSION: Third-generation cephalosporins and spectinomycin should be considered as first-choice drugs for the empirical treatment of gonorrhoea in Greece.

Anti-Bacterial Agents↗
PubMed2000

The ycf 9 (orf 62) gene in the plant chloroplast genome encodes a hydrophobic protein of stromal thylakoid membranes.

There are still some open reading frames, orfs, with unknown function in the higher plant chloroplast genome. Of these conserved orfs, designated as ycfs (hypothetical chloroplast open reading frames), one is ycf 9 (orf 62) in the transcription unit with the psbC and psbD genes. The aim of this work was to investigate the function of ycf 9 by insertional inactivation of the gene with a selectable marker cassette, consisting of the aadA coding region connected to the trc promoter and rrnB terminator. This cassette was inserted 19 bp downstream from the start of the coding region of the tobacco ycf 9 gene. Two DNA constructs with the aadA cassette in opposite orientations were precipitated on 1 micron gold particles and delivered into leaves of Nicotiana tabacum, cultivar Samsun, by the biolistic method. Spectinomycin-resistant plants regenerated following bombardment with only the construct containing the aadA gene in the opposite orientation as ycf 9. In spite of several subsequent regeneration cycles on spectinomycin, the transplastomic plants did not reach homoplasmicity. This suggests that the ycf 9 gene product is essential for chloroplast function. Using a polyclonal antibody raised against the inner part of the gene product, the polypeptide was localized in the stromal thylakoid membranes of chloroplasts.

Amino Acid Sequence↗
PubMedDate not supplied

Antibiotic susceptibility in relation to serogroup and auxotype of Neisseria gonorrhoeae isolates from Gabon.

We tested 75 beta-lactamase-positive (penicillinase-producing Neisseria gonorrhoeae; PPNG) and 147 beta-lactamase negative (non-PPNG) strains of N. gonorrhoeae obtained during a two-year period in Franceville, a semirural community in southeastern Gabon, for susceptibility to antimicrobial agents, auxotype, and serotype. The most common auxotypes were the nonrequiring and proline-requiring strains. Of the non-PPNG strains tested, 37% belonged to serogroup WI, 48% to serogroup WII, and 15% could not be grouped with commercially available antisera. Except for four strains that belonged to serogroup WII, the PPNG strains were classified as serogroup WI or ungroupable. We determined the concentrations at which 90% of strains were inhibited (MIC90) for spectinomycin (32 mg/liter for both PPNG and non-PPNG), kanamycin (32 mg/liter for both PPNG and non-PPNG), tetracycline (2 mg/liter for non-PPNG, 1 mg/liter for PPNG), cefotaxime (0.03 mg/liter for non-PPNG, 0.008 mg/liter for PPNG), and penicillin (1 mg/liter for non-PPNG, greater than 32 mg/liter for PPNG). A MIC of greater than or equal to 2 mg of tetracycline/liter was noted for 17% of the strains. Strains belonging to serogroup WII were more resistant to tetracycline and cefotaxime than other strains. Proline-requiring strains were less susceptible to tetracycline, cefotaxime, and spectinomycin than the nonrequiring strains. The decreased sensitivity to penicillin (non-PPNG strains) and tetracycline was determined by proline-requiring strains belonging to serogroup WII.

Anti-Bacterial Agents↗
PubMedDate not supplied

Antimicrobial susceptibility of Neisseria gonorrhoeae in Harare, Zimbabwe. Relationship to serogroup.

The authors investigated one hundred fifty-four isolates of Neisseria gonorrhoeae obtained from men, women, and infants in Harare, Zimbabwe, for in vitro susceptibility to various antibiotics and for reactivity with serogrouping antisera. The authors found sixty-four (42%) isolates to be WI serogroup and 90 (58%) to be WII/III. One hundred three isolates were penicillinase-producing N. gonorrhoeae (PPNG); although all of these showed resistance to penicillin, 14 isolates had an MIC to penicillin of less than 10 mg/L. All of these 14 isolates were WI serogroup. Twenty-seven of the 51 non-PPNG showed in vitro resistance to penicillin (MIC greater than 1.25 mg/L). All but one of these chromosomally resistant isolates were WII/III serogroup. With cefuroxime, tetracycline, and erythromycin, 10-15% of isolates had MICs greater than accepted breakpoints. Most isolates were susceptible to thiamphenicol, and all were susceptible to ciprofloxacin, kanamycin, and spectinomycin. The authors noted that WI isolates, whether PPNG or not, were consistently more susceptible to antibiotics than WII/III isolates. Only with kanamycin and spectinomycin were the MICs of the two serogroups similar.

Anti-Bacterial Agents↗
PubMedDate not supplied

Quinolone-resistant Neisseria gonorrhoeae in Hong Kong.

OBJECTIVE: To study the serologic characters and antibiotic susceptibilities of quinolone-resistant Neisseria gonorrhoeae in Hong Kong. STUDY DESIGN: Sixty-nine strains of Neisseria gonorrhoeae isolated from clinical failure cases after treatment with ofloxacin during the period January 1, 1992, to January 1, 1995, were studied. A panel of 14 monoclonal antibodies against protein I classified these strains into 21 serovars. The pattern of serovar distribution against varying minimum inhibitory concentrations of ofloxacin was compared with 143 strains isolated from a cohort of quinolone-susceptible, clinically responsive cases. Antibiotic susceptibilities tests were performed on quinolone-resistant strains to penicillin, tetracycline, ciprofloxacin, spectinomycin, and ceftriaxone. Epidemiologic information on location of contact was collected. RESULTS: Serologic characterization showed that Bop and Bpy were the dominant serovars among quinolone-resistant strains. Most IA and other IB serovars had declined in the selection process for quinolone resistance. Antibiotic susceptibility tests showed that 81.2%, 89.9%, and 78.3% of quinolone-resistant Neisseria gonorrhoeae strains were resistant to penicillin, tetracycline, and both, respectively, whereas 10 of 69 (14.5%) of such strains displayed high-level quinolone resistance (ofloxacin minimum inhibitory concentration > 8 micrograms/ml). The quinolone-resistant strains remained fully susceptible to spectinomycin and ceftriaxone. CONCLUSIONS: Quinolone-resistant strains have become firmly established in Hong Kong. Serovar determination has documented shifts in the gonococcal population during the selection process for quinolone resistance. Places that use quinolones in the treatment of sexually transmitted diseases should be alert to the emergence of high-level quinolone-resistant Neisseria gonorrhoeae.

Adolescent↗