Molecular Characterization of Pneumococci with Efflux-Mediated Erythromycin Resistance and Identification of a Novel
            <i>mef</i>
            Gene Subclass,
            <i>mef</i>
            (I)

Cochetti, Ileana; Vecchi, Manuela; Mingoia, Marina; Tili, Emily; Catania, Maria Rosaria; Manzin, Aldo; Varaldo, Pietro E.; Montanari, Maria Pia

doi:10.1128/aac.49.12.4999-5006.2005

Cited by 51 publications

(37 citation statements)

References 46 publications

(50 reference statements)

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“…mefA was also characterized in S. pneumoniae and was found to be carried by Tn1207.1, a portion of the original transposon described in S. pyogenes Tn1207.3 [39]. In 2005, a new mef subclass, mefI, was identified in S. pneumoniae [40]. Moreover, mefI was found to be located on the right-hand side of a newly characterized nonmobile composite structure, the 5216IQ complex, adjacent to the msr and catQ genes [41].…”

Section: Aminoglycoside Resistancementioning

confidence: 96%

Molecular mechanisms and epidemiology of resistance in Streptococcus pneumoniae in the Middle East region

Moujaber

Osman

Rafei

et al. 2017

Journal of Medical Microbiology

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Purpose. Streptococcus pneumoniae is a commensal bacterium that normally colonizes the human nasopharyngeal cavity. Once disseminated, it can cause several diseases, ranging from non-invasive infections such as acute otitis media and sinusitis through to invasive infections with higher mortality, including meningitis and septicaemia. Since the identification of the first S. pneumoniae strain with decreased susceptibility to penicillin in the 1960s, antibiotic resistance among S. pneumoniae has increased disturbingly and the mechanisms of resistance have begun to unfold.Methodology. This work briefly reviewed the available data on the molecular mechanisms underlying antimicrobial resistance and its epidemiology among pneumococcal strains in Middle Eastern countries.Key findings. Both intrinsic and acquired mechanisms (mutations, acquisition of novel mobile genetic elements and sometimes gene duplication and overexpression) affect susceptibility to a large variety of antibiotics. In Middle Eastern countries, including Lebanon, Iran, Saudi Arabia and Turkey, surveillance showed a disturbing increase in the strength and prevalence of resistance to antibiotics over the years, especially in the last decade. However, no surveillance reports were found in other Middle Eastern countries, such as Syria and Iraq.Conclusion. In order to better survey, control and prevent the emergence of multidrug-and extremely drug-resistant S. pneumoniae strains, antimicrobial stewardship, national surveillance and public awareness programmes should be developed urgently in Middle Eastern countries.

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Section: Aminoglycoside Resistancementioning

confidence: 96%

Molecular mechanisms and epidemiology of resistance in Streptococcus pneumoniae in the Middle East region

Moujaber

Osman

Rafei

et al. 2017

Journal of Medical Microbiology

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“…In addition, we documented a high rate of resistance to erythromycin and tetracycline among the S. pseudopneumoniae isolates. Recently, a single strain of S. pseudopneumoniae was found to be resistant to erythromycin and tetracycline due to the presence of mef(E) and tet(O) genes, respectively (3).…”

Section: Discussionmentioning

confidence: 99%

Characteristics of Streptococcus pseudopneumoniae Isolated from Purulent Sputum Samples

et al. 2006

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Streptococcus pseudopneumoniae is a recently described streptococcus that is phenotypically and genetically distinct from Streptococcus pneumoniae and other viridans streptococci. Key characteristics of S. pseudopneumoniae are the absence of a pneumococcal capsule, insolubility in bile, resistance or indeterminate susceptibility to optochin when incubated in 5% CO 2 but susceptibility to optochin when incubated in ambient air, and a positive reaction with the AccuProbe DNA probe hybridization test. The clinical importance of this bacterium is currently unknown. We report the characteristics and associated clinical data of 35 strains of S. pseudopneumoniae isolated from sputum samples from 33 patients. All isolates produced a positive result with the NOW S. pneumoniae antigen test (Binax, Inc.). No isolate was resistant to penicillin, but 60% were resistant to erythromycin and 77% were resistant to tetracycline. All patients had lower respiratory tract symptoms, 79% had chronic obstructive pulmonary disease (COPD), and 33% had chest radiographic infiltrates. Compared with matched control patients who had Streptococcus pneumoniae isolated from sputum, patients with S. Streptococcus pseudopneumoniae is a recently described streptococcus that is phenotypically and genetically distinct from Streptococcus pneumoniae and other viridans streptococci (1, 5). DNA-DNA homology studies suggest that this species is a member of the Streptococcus mitis-Streptococcus oralis group (1), and it is likely that this species is similar to other strains previously described by several investigators as atypical pneumococci (4, 9, 12). S. pseudopneumoniae can be differentiated from S. pneumoniae and S. mitis by the absence of a pneumococcal capsule, demonstration of insolubility in bile, resistance or indeterminate susceptibility to optochin when incubated in 5% CO 2 but susceptibility to optochin when incubated in ambient air, and a positive reaction with a commercial DNA probe hybridization test (AccuProbe Streptococcus pneumoniae culture identification test; Gen-Probe, San Diego, CA).Although the first-described isolates of S. pseudopneumoniae came from lower respiratory tract samples (1), the pathogenic potential and clinical importance of this bacterium are still undetermined. We report the characteristics and associated clinical data of 35 strains of S. pseudopneumoniae isolated from sputum samples. MATERIALS AND METHODSIsolates. Since May 2001, we have been collecting consecutive alpha-hemolytic streptococcal strains isolated from sputum samples sent to our diagnostic laboratory. Only strains isolated from good-quality samples (Ͼ25 leukocytes and Յ10 squamous epithelial cells/ϫ100 field) showing a Gram stain and culture predominance were archived. Isolates were identified as S. pseudopneumoniae on the basis of tests for pneumococcal capsule, bile solubility, optochin susceptibility, and AccuProbe DNA hybridization.Bile solubility test. 0.5 ml of 2% deoxycholate was added to 0.5-ml suspensions of each isolate prepared in phosphate...

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“…Active drug efflux is mediated by mef class genes, which include several variants: mef(A) and mef(E), which are the most common and share 90% sequence identity, and the rare variant mef(I), which has been described in only two clinical isolates from Italy (176). The genes for the three variants have been associated with different, but related, mobile genetic elements: the mef(A) gene on the defective transposon Tn1207.1 or the closely related transposon Tn1207.3 (177), mef(E) on the "macrolide efflux genetic assembly" (mega) element (178), and mef(I) on a nonmobile composite structure designated the 5216IQ complex (179).…”

Section: Efflux Mechanismmentioning

confidence: 99%

Biological and Epidemiological Features of Antibiotic-Resistant Streptococcus pneumoniae in Pre- and Post-Conjugate Vaccine Eras: a United States Perspective

et al. 2016

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SUMMARYStreptococcus pneumoniaeinflicts a huge disease burden as the leading cause of community-acquired pneumonia and meningitis. Soon after mainstream antibiotic usage, multiresistant pneumococcal clones emerged and disseminated worldwide. Resistant clones are generated through adaptation to antibiotic pressures imposed while naturally residing within the human upper respiratory tract. Here, a huge array of related commensal streptococcal strains transfers core genomic and accessory resistance determinants to the highly transformable pneumococcus. β-Lactam resistance is the hallmark of pneumococcal adaptability, requiring multiple independent recombination events that are traceable to nonpneumococcal origins and stably perpetuated in multiresistant clonal complexes. Pneumococcal strains with elevated MICs of β-lactams are most often resistant to additional antibiotics. Basic underlying mechanisms of most pneumococcal resistances have been identified, although new insights that increase our understanding are continually provided. Although all pneumococcal infections can be successfully treated with antibiotics, the available choices are limited for some strains. Invasive pneumococcal disease data compiled during 1998 to 2013 through the population-based Active Bacterial Core surveillance program (U.S. population base of 30,600,000) demonstrate that targeting prevalent capsular serotypes with conjugate vaccines (7-valent and 13-valent vaccines implemented in 2000 and 2010, respectively) is extremely effective in reducing resistant infections. Nonetheless, resistant non-vaccine-serotype clones continue to emerge and expand.

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Molecular Characterization of Pneumococci with Efflux-Mediated Erythromycin Resistance and Identification of a Novel mef Gene Subclass, mef (I)

Cited by 51 publications

References 46 publications

Molecular mechanisms and epidemiology of resistance in Streptococcus pneumoniae in the Middle East region

Molecular mechanisms and epidemiology of resistance in Streptococcus pneumoniae in the Middle East region

Characteristics of Streptococcus pseudopneumoniae Isolated from Purulent Sputum Samples

Biological and Epidemiological Features of Antibiotic-Resistant Streptococcus pneumoniae in Pre- and Post-Conjugate Vaccine Eras: a United States Perspective

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