scholarly journals Detection of Tn917-Like Sequences within a Tn916-like Conjugative Transposon (Tn3872) in Erythromycin-Resistant Isolates of Streptococcus pneumoniae

1998 ◽  
Vol 42 (9) ◽  
pp. 2312-2318 ◽  
Author(s):  
Linda K. McDougal ◽  
Fred C. Tenover ◽  
Linda N. Lee ◽  
J. Kamile Rasheed ◽  
Jan E. Patterson ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Nucleotide Sequence ◽  
Dna Hybridization ◽  
Antimicrobial Agents ◽  
Kanamycin Resistance ◽  
Sequence Analyses ◽  
Conjugative Transposon ◽  
Resistance Phenotype ◽  
Genetic Elements ◽  
Resistant Strains

ABSTRACT A series of macrolide-lincosamide-streptogramin B (MLS)-resistant pneumococcal isolates of a variety of serotypes was examined and was found to contain Tn917-like elements by DNA-DNA hybridization. Like Tn1545, Tn917 also encodes an ermAM gene but does not mediate resistance to other antimicrobial agents. Furthermore, nucleotide sequence analyses of the DNAs flanking three of the Tn917-like elements revealed that they were inserted into orf9 of a Tn916-like element in a composite transposon-like structure (Tn3872). Other MLS-resistant strains appeared to contain Tn1545-like elements that had suffered a deletion of sequences including the aphA-3 sequences responsible for kanamycin resistance. Thus, the MLS resistance phenotype in pneumococci appears to be mediated by the ermAM present on a much wider variety of genetic elements than was previously appreciated.

scholarly journals In Vitro Selection of Resistance to Four β-Lactams and Azithromycin in Streptococcus pneumoniae

1998 ◽  
Vol 42 (11) ◽  
pp. 2914-2918 ◽  
Author(s):  
Glenn A. Pankuch ◽  
Shane A. Jueneman ◽  
Todd A. Davies ◽  
Michael R. Jacobs ◽  
Peter C. Appelbaum
Keyword(s):  
Streptococcus Pneumoniae ◽  
In Vitro Selection ◽  
Antimicrobial Agents ◽  
Penicillin G ◽  
Resistance Selection ◽  
Resistant Strains ◽  
Selection Of ◽  
Selection Of Resistance

ABSTRACT Selection of resistance to amoxicillin (with or without clavulanate), cefaclor, cefuroxime, and azithromycin among six penicillin G- and azithromycin-susceptible pneumococcal strains and among four strains with intermediate penicillin sensitivities (azithromycin MICs, 0.125 to 4 μg/ml) was studied by performing 50 sequential subcultures in medium with sub-MICs of these antimicrobial agents. For only one of the six penicillin-susceptible strains did subculturing in medium with amoxicillin (with or without clavulanate) lead to an increased MIC, with the MIC rising from 0.008 to 0.125 μg/ml. Five of the six penicillin-susceptible strains showed increased azithromycin MICs (0.5 to >256.0 μg/ml) after 17 to 45 subcultures. Subculturing in medium with cefaclor did not affect the cefaclor MICs of three strains but and led to increased cefaclor MICs (from 0.5 to 2.0 to 4.0 μg/ml) for three of the six strains, with MICs of other β-lactams rising 1 to 3 twofold dilutions. Subculturing in cefuroxime led to increased cefuroxime MICs (from 0.03 to 0.06 μg/ml to 0.125 to 0.5 μg/ml) for all six strains without significantly altering the MICs of other β-lactams, except for one strain, which developed an increased cefaclor MIC. Subculturing in azithromycin did not affect β-lactam MICs. Subculturing of the four strains with decreased penicillin susceptibility in amoxicillin (with or without clavulanate) or cefuroxime did not select for β-lactam resistance. Subculturing of one strain in cefaclor led to an increase in MIC from 0.5 to 2.0 μg/ml after 19 passages. In contrast to strains that were initially azithromycin susceptible, which required >10 subcultures for resistance selection, three of four strains with azithromycin MICs of 0.125 to 4.0 μg/ml showed increased MICs after 7 to 13 passages, with the MICs increasing to 16 to 32 μg/ml. All azithromycin-resistant strains were clarithromycin resistant. With the exception of strains that contained mefE at the onset, no strains that developed resistance to azithromycin containedermB or mefE, genes that have been found in macrolide-resistant pneumococci obtained from clinic patients.

Canadian national survey of prevalence of antimicrobial resistance among clinical isolates of Streptococcus pneumoniae. Canadian Bacterial Surveillance Network.

1996 ◽  
Vol 40 (9) ◽  
pp. 2190-2193 ◽  
Author(s):  
A E Simor ◽  
M Louie ◽  
D E Low
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Beta Lactam ◽  
Surveillance Network ◽  
Antibiotic Resistant ◽  
Intermediate Resistance ◽  
Resistant Strains ◽  
High Level ◽  
Level Resistance

The antimicrobial susceptibilities of 1,089 clinical isolates of Streptococcus pneumoniae obtained from 39 laboratories across Canada between October 1994 and August 1995 were determined. A total of 91 isolates (8.4%) demonstrated intermediate resistance (MIC, 0.1 to 1.0 microgram/ml) and 36 (3.3%) had high-level resistance (MIC, > or = 2.0 micrograms/ml) to penicillin. Penicillin-resistant strains were more likely to have been recovered from normally sterile sites (P = 0.005) and to be cross-resistant to several beta-lactam and non-beta-lactam antimicrobial agents (P < 0.05). These results indicate that there has been a recent significant increase in the prevalence of antibiotic-resistant S. pneumoniae in Canada.

scholarly journals Antimicrobial Resistance among Clinical Isolates of Streptococcus pneumoniae in Canada during 2000

2002 ◽  
Vol 46 (5) ◽  
pp. 1295-1301 ◽  
Author(s):  
Donald E. Low ◽  
Joyce de Azavedo ◽  
Karl Weiss ◽  
Tony Mazzulli ◽  
Magdalena Kuhn ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Resistance ◽  
Respiratory Tract ◽  
Lower Respiratory Tract ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Central Laboratory ◽  
Resistant Strains ◽  
Resistance Rates

ABSTRACT A total of 2,245 clinical isolates of Streptococcus pneumoniae were collected from 63 microbiology laboratories from across Canada during 2000 and characterized at a central laboratory. Of these isolates, 12.4% were not susceptible to penicillin (penicillin MIC, ≥0.12 μg/ml) and 5.8% were resistant (MIC, ≥2 μg/ml). Resistance rates among non-β-lactam agents were the following: macrolides, 11.1%; clindamycin, 5.7%; chloramphenicol, 2.2%; levofloxacin, 0.9%; gatifloxacin, 0.8%; moxifloxacin, 0.4%; and trimethoprim-sulfamethoxazole, 11.3%. The MICs at which 90% of the isolates were inhibited (MIC90s) of the fluoroquinolones were the following: gemifloxacin, 0.03 μg/ml; BMS-284756, 0.06 μg/ml; moxifloxacin, 0.12 μg/ml; gatifloxacin, 0.25 μg/ml; levofloxacin, 1 μg/ml; and ciprofloxacin, 1 μg/ml. Of 578 isolates from the lower respiratory tract, 21 (3.6%) were inhibited at ciprofloxacin MICs of ≥4 μg/ml. None of the 768 isolates from children were inhibited at ciprofloxacin MICs of ≥4 μg/ml, compared to 3 of 731 (0.6%) from those ages 15 to 64 (all of these >60 years old), and 27 of 707 (3.8%) from those over 65. The MIC90s for ABT-773 and telithromycin were 0.015 μg/ml for macrolide-susceptible isolates and 0.12 and 0.5 μg/ml, respectively, for macrolide-resistant isolates. The MIC of linezolid was ≤2 μg/ml for all isolates. Many of the new antimicrobial agents tested in this study appear to have potential for the treatment of multidrug-resistant strains of pneumococci.

scholarly journals Emergence of Fluoroquinolone Resistance among Multiply Resistant Strains of Streptococcus pneumoniae in Hong Kong

1999 ◽  
Vol 43 (5) ◽  
pp. 1310-1313 ◽  
Author(s):  
Pak-Leung Ho ◽  
Tak-Lun Que ◽  
Dominic Ngai-Chong Tsang ◽  
Tak-Keung Ng ◽  
Kin-Hung Chow ◽  
...  
Keyword(s):  
Hong Kong ◽  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Fluoroquinolone Resistance ◽  
The Future ◽  
Resistant Strains

ABSTRACT The MICs of 17 antimicrobial agents for 181 Streptococcus pneumoniae strains were determined by the E-test. Overall, 69.1% were penicillin resistant (MIC > 0.06 μg/ml). Resistance to ciprofloxacin (MIC > 2 μg/ml), levofloxacin (MIC > 2 μg/ml), or trovafloxacin (MIC > 1 μg/ml) was found in 12.1, 5.5, or 2.2% of the strains, respectively. These high rates of resistance raise concerns for the future.

scholarly journals Antimicrobial resistance of Streptococcus pneumoniae recovered from outpatients in the United States during the winter months of 1994 to 1995: results of a 30-center national surveillance study.

1996 ◽  
Vol 40 (5) ◽  
pp. 1208-1213 ◽  
Author(s):  
G V Doern ◽  
A Brueggemann ◽  
H P Holley ◽  
A M Rauch
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Clinical Laboratory ◽  
Rank Order ◽  
The United States ◽  
Penicillin Resistance ◽  
National Committee ◽  
Medical Centers ◽  
Resistant Strains ◽  
High Level

A total of 1,527 clinically significant outpatient isolates of Streptococcus pneumoniae were prospectively collected in 30 different U.S. medical centers between November 1994 and April 1995. Overall, 23.6% of strains were not susceptible to penicillin, with 14.1% intermediate and 9.5% high-level resistant. The frequencies of recovery of intermediate and high-level resistant strains varied considerably between different medical centers and in different geographic areas. In general, intermediate and high-level penicillin resistance was most common with isolates of S. pneumoniae recovered from pediatric patients. The in vitro activities of 22 other antimicrobial agents were assessed against this collection of isolates. Ampicillin was consistently 1 twofold dilution less active than penicillin. Amoxicillin and amoxicillin-clavulanate were essentially equivalent to penicillin in activity. The rank order of activity for cephalosporins was cefotaxime = ceftriaxone > or = cefpodoxime > or = cefuroxime > cefprozil > or = cefixime > cefaclor = loracarbef > cefadroxil = cephalexin. The National Committee for Clinical Laboratory Standards [Performance Standards for Antimicrobial Susceptibility Testing, Sixth Information Supplement (M100-S6), 1995] has established MIC breakpoints for resistance (i.e., > or = 2 micrograms/ml) with three cephalosporins versus S. pneumoniae, namely, cefotaxime, ceftriaxone, and cefuroxime. The overall percentages of strains resistant to these three antimicrobial agents were 3, 5, and 12, respectively. The overall frequency of resistance was 10% with all three macrolides examined in this study, clarithromycin, erythromycin, and azithromycin. The overall percentages of chloramphenicol, tetracycline, and trimethoprim-sulfamethoxazole resistance were 4.3, 7.5, and 18, respectively. The resistance percentages among the cephalosporins, macrolides, chloramphenicol, tetracycline, and trimethoprim-sulfamethoxazole were consistently higher among penicillin-intermediate strains than among susceptible isolates and even higher still among organisms expressing high-level penicillin resistance. Multiply resistant strains represented 9.1% of the organisms examined in this study. Finally, rifampin resistance was uncommon (i.e., 0.5%), and vancomycin resistance was not detected. The quinopristin-dalfopristin combination was consistently active at concentrations of 0.25 to 4 micrograms/ml, but rates of resistance could not be determined in the absence of established interpretive criteria for MIC results.

scholarly journals Activities of Clinafloxacin, Gatifloxacin, Gemifloxacin, and Trovafloxacin against Recent Clinical Isolates of Levofloxacin-Resistant Streptococcus pneumoniae

2000 ◽  
Vol 44 (11) ◽  
pp. 2962-2968 ◽  
Author(s):  
J. H. Jorgensen ◽  
L. M. Weigel ◽  
J. M. Swenson ◽  
C. G. Whitney ◽  
M. J. Ferraro ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Clinical Laboratory ◽  
Dna Gyrase ◽  
Test Methods ◽  
Clinical Isolates ◽  
Disk Diffusion ◽  
National Committee ◽  
Sequence Analyses ◽  
Topoisomerase Iv ◽  
Resistant Strains

ABSTRACT The activities of two investigational fluoroquinolones and three fluoroquinolones that are currently marketed were determined for 182 clinical isolates of Streptococcus pneumoniae. The collection included 57 pneumococcal isolates resistant to levofloxacin (MIC ≥ 8 μg/ml) recovered from patients in North America and Europe. All isolates were tested with clinafloxacin, gatifloxacin, gemifloxacin, levofloxacin, and trovafloxacin by the National Committee for Clinical Laboratory Standards broth microdilution and disk diffusion susceptibility test methods. Gemifloxacin demonstrated the greatest activity on a per gram basis, followed by clinafloxacin, trovafloxacin, gatifloxacin, and levofloxacin. Scatterplots of the MICs and disk diffusion zone sizes revealed a well-defined separation of levofloxacin-resistant and -susceptible strains when the isolates were tested against clinafloxacin and gatifloxacin. DNA sequence analyses of the quinolone resistance-determining regions of gyrA,gyrB, parC, and parE from 21 of the levofloxacin-resistant strains identified eight different patterns of amino acid changes. Mutations among the four loci had the least effect on the MICs of gemifloxacin and clinafloxacin, while the MICs of gatifloxacin and trovafloxacin increased by up to six doubling dilutions. These data indicate that the newer fluoroquinolones have greater activities than levofloxacin against pneumococci with mutations in the DNA gyrase or topoisomerase IV genes. Depending upon pharmacokinetics and safety, the greater potency of these agents could provide improved clinical efficacy against levofloxacin-resistant pneumococcal strains.

scholarly journals Antipneumococcal Activities of a Ketolide (HMR 3647), a Streptogramin (Quinupristin-Dalfopristin), a Macrolide (Erythromycin), and a Lincosamide (Clindamycin)

1998 ◽  
Vol 42 (4) ◽  
pp. 945-946 ◽  
Author(s):  
A. L. Barry ◽  
P. C. Fuchs ◽  
S. D. Brown
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Macrolide Resistance ◽  
Low Level ◽  
Resistant Strains ◽  
High Level

ABSTRACT Four different compounds belonging to the macrolide-lincosamide-streptogramin B (MLSb) class of antimicrobial agents were tested against 611 Streptococcus pneumoniae strains. The ketolide (HMR 3647, previously RU66647) and the streptogramin (quinupristin-dalfopristin) were both active against pneumococci with high-level MLSb resistance (clindamycin-resistant strains) as well as those with low-level macrolide resistance (clindamycin-susceptible strains).

scholarly journals Nucleotide Sequence Analysis of Integrative Conjugative Element Tn5253of Streptococcus pneumoniae

2013 ◽  
Vol 58 (2) ◽  
pp. 1235-1239 ◽  
Author(s):  
Francesco Iannelli ◽  
Francesco Santoro ◽  
Marco R. Oggioni ◽  
Gianni Pozzi
Keyword(s):  
Streptococcus Pneumoniae ◽  
Sequence Analysis ◽  
Nucleotide Sequence ◽  
Streptococcus Pyogenes ◽  
Open Reading Frames ◽  
Nucleotide Sequence Analysis ◽  
Conjugative Transposon ◽  
Content Type ◽  
Integrative Conjugative Element ◽  
Reading Frames

ABSTRACTConjugative transposon Tn5253, an integrative conjugative element (ICE) ofStreptococcus pneumoniaecarrying thecatandtet(M) genes, was shown to be 64,528 bp in size and to contain 79 open reading frames, of which only 38 could be annotated. Two distinct genetic elements were found integrated into Tn5253: Tn5251(18,033 bp), of the Tn916-Tn1545family of ICEs, and Ωcat(pC194) (7,627 bp), which could not conjugate but was capable of intracellular mobility by excision, circularization, and integration by homologous recombination. The highest conjugation frequency of Tn5253was observed whenStreptococcus pyogeneswas the donor (6.7 × 10−3transconjugants/donor).

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