Increased carriage of resistant non-pneumococcal α-hemolytic streptococci after antibiotic therapy

Ghaffar, Faryal; Friedland, Ian R.; Katz, Kathy; Muniz, Luz Stella; Smith, Jeanette L.; Davis, Phyllis; Reynolds, Jason; McCracken, George H.

doi:10.1016/s0022-3476(99)70061-2

Cited by 27 publications

(16 citation statements)

References 27 publications

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“…This is in agreement with studies that have shown an increase of the carriage of resistant nonpneumococcal alpha-hemolytic streptococci after antibiotic therapy (53,54). Apparently, these commensal streptococci may serve as a reservoir long after the occurrence of selective pressure of betalactam antibiotic usage because the fitness cost of the resistant phenotype appears to be lower in S. mitis and S. oralis strains than in S. pneumoniae strains.…”

Section: Discussionsupporting

confidence: 91%

Commensal Streptococci Serve as a Reservoir for β-Lactam Resistance Genes in Streptococcus pneumoniae

Jensen

Valdórsson

Frimodt‐Møller

et al. 2015

Antimicrob Agents Chemother

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c Streptococcus pneumoniae is a leading cause of pneumonia, meningitis, septicemia, and middle ear infections. The incidence of S. pneumoniae isolates that are not susceptible to penicillin has risen worldwide and may be above 20% in some countries. Betalactam antibiotic resistance in pneumococci is associated with significant sequence polymorphism in penicillin-binding proteins (PBPs). Commensal streptococci, especially S. mitis and S. oralis, have been identified as putative donors of mutated gene fragments. However, no studies have compared sequences of the involved pbp genes in large collections of commensal streptococci with those of S. pneumoniae. We therefore investigated the sequence diversity of the transpeptidase region of the three pbp genes, pbp2x, pbp2b, and pbp1a in 107, 96, and 88 susceptible and nonsusceptible strains of commensal streptococci, respectively, at the nucleotide and amino acid levels to determine to what extent homologous recombination between commensal streptococci and S. pneumoniae plays a role in the development of beta-lactam resistance in S. pneumoniae. In contrast to pneumococci, extensive sequence variation in the transpeptidase region of pbp2x, pbp2b, and pbp1a was observed in both susceptible and nonsusceptible strains of commensal streptococci, conceivably reflecting the genetic diversity of the many evolutionary lineages of commensal streptococci combined with the recombination events occurring with intra-and interspecies homologues. Our data support the notion that resistance to beta-lactam antibiotics in pneumococci is due to sequences acquired from commensal Mitis group streptococci, especially S. mitis. However, several amino acid alterations previously linked to beta-lactam resistance in pneumococci appear to represent species signatures of the donor strain rather than being causal of resistance.

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Section: Discussionsupporting

confidence: 91%

Commensal Streptococci Serve as a Reservoir for β-Lactam Resistance Genes in Streptococcus pneumoniae

Jensen

Valdórsson

Frimodt‐Møller

et al. 2015

Antimicrob Agents Chemother

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“…With respect to penicillin, the story is the same. Studies have shown that VGS penicillin resistance rates are significantly higher in those patients receiving penicillin than in those who are not (23).…”

Section: Antimicrobial Susceptibilities Of Viridansmentioning

confidence: 99%

It's Not Easy Being Green: the Viridans Group Streptococci, with a Focus on Pediatric Clinical Manifestations

2010

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2The viridans group streptococci (VGS) are a heterogeneous group of organisms that can be human commensals, colonizing the gastrointestinal and genitourinary tracts in addition to the oral mucosa. VGS are generally considered to be of low pathogenic potential in immunocompetent individuals. However, in certain patient populations, VGS can cause invasive disease, such as endocarditis, intra-abdominal infection, and shock. Within the VGS, the rates and patterns of antimicrobial resistance vary greatly depending upon the species identification and the patient population. In general, Streptococcus mitis group organisms are resistant to more antimicrobial agents than the other VGS species. This review addresses current VGS taxonomy, in addition to the current methodologies being used in clinical microbiology laboratories for identification of VGS. Automated systems struggle overall with species level identification and susceptibility testing for VGS. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) identification is emerging as a potential alternative for organism identification. A review of recent pediatric-specific data regarding the clinical manifestations of VGS revealed that the Streptococcus anginosus group (SAG) organisms may be important pathogens in pediatric patients and that the VGS may contribute to disease in patients with cystic fibrosis. It also appears that rates of antimicrobial resistance in VGS in pediatric patients are surpassing those of the adult population. TAXONOMY AND MICROBIOLOGYThe viridans group streptococci (VGS) are a heterogeneous group of organisms that can be both commensal flora and pathogens in humans. They are the "grab bag" that remains when the beta-hemolytic streptococci, enterococci, and pneumococci are excluded from the streptococci. The purpose of this review is to summarize the currently accepted taxonomic classification of this group of organisms, examine the state of the art for identification of the VGS, and then focus on the pediatric clinical manifestations associated with the VGS.Perhaps the only consistency observed in discussions regarding the taxonomy of the VGS is a lack of consistency. The taxonomy is very controversial, and for many years, a standardized naming scheme or typing system for this group of organisms was lacking; therefore, discussions on this topic frequently include the phrase "poorly classified." There are now at least 30 recognized species of VGS (11,14).

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“…(16) Furthermore, loss of AHS due to antibiotic treatment raises the risk of colonization by otopathogens as well as AOM. (17–19)…”

Section: Introductionmentioning

confidence: 99%

Impact of Respiratory Viral Infections on α-Hemolytic Streptococci and Otopathogens in the Nasopharynx of Young Children

Friedel

Chang²,

Wills³

et al. 2013

Pediatric Infectious Disease Journal

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Background We studied nasopharyngeal (NP) colonization in a cohort of children to determine the impact of viral upper respiratory infections (URI) on non-pneumococcal alpha hemolytic streptococci (AHS) and otopathogen colonization in association with acute otitis media (AOM). Methods NP samples were collected routinely when children were aged 6, 9, 12, 15, 18, 24, and 30 months and during episodes of AOM. NP samples were prospectively obtained from 248 children during a 5-year time span; 1,018 during routine visits, 161 at the time of AOM and 59 at follow-up visits 3 weeks after AOM. Results The overall NP colonization rate of AHS was 50.8% during a non-AOM visit but declined to 38.3% during a viral URI with concurrent AOM (p=0.0006). Of 56 AOM visits with paired follow-ups, 6 (10.7%) had AHS in the NP at the time of viral URI and concurrent AOM whereas 29 (51.8%) had AHS at the follow-up (p<0.001). Lower NP colonization rates with AHS were associated with significant increases in Streptococcus pneumoniae carriage during non-AOM visits (p<0.001) and during viral URI and concurrent AOM visits (p=0.003). AHS NP colonization rates were not different when children had a viral URI without AOM versus when they were URI negative, but NP colonization with non-typeable Haemophilus influenzae rates increased (p<0.001) and Moraxella catarrhalis decreased (p<0.001) during viral URI. Conclusion Respiratory viral infections alter NP carriage rates of commensal AHS and otopathogens, including prior to AOM.

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Increased carriage of resistant non-pneumococcal α-hemolytic streptococci after antibiotic therapy

Cited by 27 publications

References 27 publications

Commensal Streptococci Serve as a Reservoir for β-Lactam Resistance Genes in Streptococcus pneumoniae

Commensal Streptococci Serve as a Reservoir for β-Lactam Resistance Genes in Streptococcus pneumoniae

It's Not Easy Being Green: the Viridans Group Streptococci, with a Focus on Pediatric Clinical Manifestations

Impact of Respiratory Viral Infections on α-Hemolytic Streptococci and Otopathogens in the Nasopharynx of Young Children

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