Antibiotic resistance rates and macrolide resistance phenotypes of viridans group streptococci from the oropharynx of healthy Greek children

Ioannidou, Sofia; Tassios, Panayotis T.; Kotsovili-Tseleni, A.; Foustoukou, M.; Legakis, Nicholas J.; Vatopoulos, A.

doi:10.1016/s0924-8579(00)00338-1

Cited by 44 publications

(37 citation statements)

References 32 publications

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“…Although this finding is similar to the finding from Greece (74%) (28), it was found that the percentages of mef(A) and erm(B) among erythromycin-resistant viridans group streptococci were the same (4). In the latter study, both resistance genes were found in one strain and that strain showed the MLS B phenotype.…”

Section: Discussionsupporting

confidence: 87%

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Molecular Epidemiology And Antibacterial Susceptibility Of Streptococci Isolated From Healthy Children Attending Day Care Units

Perçin¹,

Bozdoğan²,

Ayangil³

et al. 2010

TUTFD

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Objective: The aims of the study were to investigate antibacterial susceptibility and resistance mechanisms of streptococci isolated from healthy children attending day care units and to evaluate clonal relatedness of the strains.Material and Methods: Antimicrobial susceptibilities of streptococci isolated from 212 children attending 3 different day care units were evaluated using the agar dilution method. Polymerase chain reaction and sequencing were used to investigate resistance mechanisms. Clonal relatedness was evaluated using pulsed field gel electrophoresis.Results: Of 212 children, 11 (5.2%) carried Streptococcus pneumoniae, 17 (8.0%) S. pyogenes, and 42 (19.8%) erythromycin resistant viridans group streptococci. All S. pyogenes were susceptible to penicillin G and macrolides. Ten of 11 clonally unique S. pneumoniae were resistant to penicillin G. Three of 11 S. pneumoniae were macrolide resistant and carried erm(B). Among clonally unique 42 erythromycin resistant viridans group streptococci, 2 (4.8%) had erm(B), 33 (78.6%) had mef(A) and 7 (16.6%) had both erm(B) and mef(A) genes. All S. pyogenes from the first centre and three strains from the second centre were pulse-type A.Conclusion: Among healthy children, colonization with penicillin resistant pneumococci and erythromycin resistant viridans group streptococci is quite high. Clonal spread of S. pyogenes is important for day care units.

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Section: Discussionsupporting

confidence: 87%

“…MIC 90 s of levofloxacin for both S. pyogenes and erythromycin-resistant viridans group streptococci were similar (2 mg/L) to those in other studies (28,32). There was only one strain of erythromycin-resistant viridans group streptococci intermediately-resistant to levofloxacin, but it did not have mutations in type II topoisomerase.…”

Section: Discussionsupporting

confidence: 80%

Molecular Epidemiology And Antibacterial Susceptibility Of Streptococci Isolated From Healthy Children Attending Day Care Units

Perçin¹,

Bozdoğan²,

Ayangil³

et al. 2010

TUTFD

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“…High rates of resistance to penicillin and high MICs are frequent among S. mitis isolates (13,32,33). Therefore, misidentification of SMG isolates such as those described here can result in overreported levels of penicillin resistance, a problem previously identified (36,46).…”

Section: Vol 48 2010 Penicillin-resistant Pneumococcus-like Strainsmentioning

confidence: 68%

Highly Penicillin-Resistant Multidrug-Resistant Pneumococcus-Like Strains Colonizing Children in Oeiras, Portugal: Genomic Characteristics and Implications for Surveillance

et al. 2010

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While performing surveillance studies in Oeiras, Portugal, designed to describe the impact of pneumococcal conjugate vaccine on colonization, we observed an increase from 0.7% in 2003 to 5% in 2006 in the prevalence of penicillin resistance (MIC of 2 to 6 mg/liter) among presumptively identified pneumococcal isolates. Although 15 of the 22 penicillin-resistant isolates obtained in 2006 were optochin resistant, they were bile soluble and thus considered to be bona fide pneumococci. This study aimed to clarify the nature of these isolates by using a combination of phenotypic and genotypic approaches that included routine strategies for pneumococcal identification, multilocus sequence analysis (MLSA), and comparative genomic hybridization (CGH). By MLSA, all isolates were classified as "streptococci of the mitis group" that, however, were distinct from typical Streptococcus pneumoniae or Streptococcus mitis. A single isolate was identified as Streptococcus pseudopneumoniae. CGH confirmed these findings and further indicated that a considerable part of the proposed pneumococcal core genome is conserved in these isolates, including several pneumococcal virulence genes (e.g., pavA, spxB, cbpE, and cbpD). These results suggest that among pneumococci and closely related streptococci, universal unique phenotypic and genetic properties that could aid species identification are virtually impossible to define. In pneumococcal colonization studies, when atypical strains are found, MLSA and CGH are informative tools that can be used to complement routine tests. In our study, after correct identification of the penicillin-resistant true pneumococci, we found that penicillin resistance levels among pneumococci remained stable from 2003 to 2006.Streptococcus pneumoniae is a bacterial pathogen that frequently colonizes the nasopharynx of humans, particularly young children of preschool age. Colonization is mostly asymptomatic and only rarely results in disease (3). However, when disease does occur, it may range from a mild infection such as otitis media to severe septicemia or meningitis. Globally, the morbidity and mortality associated with pneumococcal infections are extremely high. A recent report from the WHO estimated that 0.7 to 1.0 million deaths occur annually among children Ͻ5 years of age as a result of pneumococcal infections (50).Four phenotypic characteristics are classically used in the diagnostic laboratory for the presumptive identification of S. pneumoniae: colony morphology (colonies with a depression in the center showing alpha-hemolysis on sheep blood agar), optochin susceptibility, deoxycholate (DOC) solubility (commonly referred to as bile solubility), and a positive reaction with antipneumococcal polysaccharide capsule antibodies (20). In particular, optochin susceptibility and deoxycholate solubility have been associated with high sensitivity and specificity (between 98% and 100%). However, a number of studies have reported on sporadic optochin-resistant S. pneumoniae isolates (28, 34) and rare deoxycholat...

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“…Tetracycline resistance is encoded by tet genes. Antibiotic profiling of α-hemolytic streptococci isolated from the oropharynx of healthy Greek children showed a high percent of tetracycline resistant isolates [118], the majority of isolates being represented by S. mitis. Okamoto et al [119] studied the prevalence of tetQ gene in genus Porphyromonas and Prevotella sp.…”

Section: Mechanisms Of Dental Plaque Resistance To Antimicrobials Andmentioning

confidence: 99%

Impact of Dental Plaque Biofilms in Periodontal Disease: Management and Future Therapy

Lazăr¹,

Dițu²,

Curuţiu³

et al. 2017

Periodontitis - A Useful Reference

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Oral cavity represents an ideal environment for the microbial cell growth, persistence, and dental plaque establishment. The presence of different microniches leads to the occurrence of different biofilm communities, formed on teeth surface, above gingival crevice or at subgingival level, on tongue, mucosa and dental prosthetics too. The healthy state is regulated by host immune system and interactions between microbial community members, maintaining the predominance of "good" microorganisms. When the complexity and volume of biofilms from the gingival crevice increase, chronic pathological conditions such as gingivitis and periodontitis can occur, predisposing to a wide range of complications. Bacteria growing in biofilms exhibit a different behavior compared with their counterpart, respectively planktonic or free cells. There have been described numerous mechanisms of differences in antibiotic susceptibility of biofilm embedded cells. Resistance to antibiotics, mediated by genetic factors or, phenotypical, due to biofilm formation, called also tolerance, is the most important cause of therapy failure of biofilm-associated infections, including periodontitis; the mechanisms of tolerance are different, the metabolic low rate and cell's dormancy being the major ones. The recent progress in science and technology has made possible a wide range of novel approaches and advanced therapies, aiming the efficient management of periodontal disease.

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Antibiotic resistance rates and macrolide resistance phenotypes of viridans group streptococci from the oropharynx of healthy Greek children

Cited by 44 publications

References 32 publications

Molecular Epidemiology And Antibacterial Susceptibility Of Streptococci Isolated From Healthy Children Attending Day Care Units

Molecular Epidemiology And Antibacterial Susceptibility Of Streptococci Isolated From Healthy Children Attending Day Care Units

Highly Penicillin-Resistant Multidrug-Resistant Pneumococcus-Like Strains Colonizing Children in Oeiras, Portugal: Genomic Characteristics and Implications for Surveillance

Impact of Dental Plaque Biofilms in Periodontal Disease: Management and Future Therapy

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