Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-6 (of 6 Records) |
Query Trace: Facklam R[original query] |
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Assessment of a novel bile solubility test and MALDI-TOF for the differentiation of Streptococcus pneumoniae from other mitis group streptococci
Slotved HC , Facklam RR , Fuursted K . Sci Rep 2017 7 (1) 7167 This study assesses a novel bile solubility test and MALDI-TOF for the differentiation of Streptococcus pneumoniae from other mitis group streptococci, including differentiation of S. pneumoniae from Streptococcus pseudopneumoniae. Eighty-four species verified mitis group isolates were subjected to our bile solubility test (which measures and calculates the differences of absorbance in the test tube containing 10% sodium deoxycholate versus a blank control tube, after incubation for 10 minutes at 36 degrees C using a spectrophotometer) and MALDI-TOF MS (both the standard result output and by visual spectra evaluation). Applying a calculated optimal cut-off absorbance-value of 2.1, differentiated S. pneumoniae from all but one other mitis group streptococci (one S. mitis isolate generated an OD-value above 2.1). MALDI-TOF score value identification identified correctly 46 S. pneumoniae and 4 S. pseudopneumoniae but misidentified 16 other mitis group strains. Visual spectra evaluation correctly identified all S. pneumoniae and S. pseudopneumoniae strains but misidentified 13 other mitis group strains. The bile solubility test based on spectrophotometric reading described in this study can differentiate S. pneumoniae from other Streptococcus species. Combining the bile solubility test and the MALDI-TOF spectra results provide a correct identification of all S. pneumoniae and S. pseudopneumoniae isolates. |
Evaluation of methods for identification and determination of the taxonomic status of strains belonging to the Streptococcus porcinus-Streptococcus pseudoporcinus complex isolated from animal, human, and dairy sources
Shewmaker PL , Steigerwalt AG , Whitney AM , Morey RE , Graziano JC , Facklam RR , Musser KA , Merquior VL , Teixeira LM . J Clin Microbiol 2012 50 (11) 3591-7 Ninety-seven animal, human, and dairy Streptococcus porcinus or Streptococcus pseudoporcinus isolates in the CDC Streptococcus strain collection were evaluated based on DNA-DNA reassociation, 16S rRNA and rpoB gene sequencing, conventional biochemical and rapid ID 32 STREP identification methods, and antimicrobial susceptibility testing to determine their taxonomic status, characteristics for species differentiation, antimicrobial susceptibility and relevance of clinical source. Nineteen of the 97 isolates (1 human, 18 swine) were identified as S. porcinus. The remaining 72 human isolates and 6 dairy isolates were identified as S. pseudoporcinus. The use of 16S rRNA or rpoB gene sequencing was required to differentiate S. porcinus from S. pseudoporcinus. The human and dairy S. pseudoporcinus isolates were biochemically distinct from each other as well as distinct by 16S rRNA and rpoB gene sequencing. Therefore, we propose the subspecies denominations S. pseudoporcinus subsp. hominis subsp. nov. for the human isolates and S. pseudoporcinus subsp. lactis subsp. nov. for the dairy isolates. Most strains were susceptible to the antimicrobials tested, with the exception of tetracycline. Two strains of each species were also resistant to clindamycin and erythromycin and carried the erm(A) (S. pseudoporcinus) or the erm(B) (S. porcinus) genes. S. porcinus was identified from a single human isolate recovered from a wound in an abattoir worker. S. pseudoporcinus was primarily isolated from the genitourinary tract of women, but was also associated with blood, placental, and wound infections. Isolates reacting with group B antiserum and demonstrating wide beta hemolysis should be suspected of being S. pseudoporcinus and not S. agalactiae. |
Reevaluation of the taxonomic status of recently described species of Enterococcus: evidence that E. thailandicus is a senior subjective synonym of "E. sanguinicola" and confirmation of E. caccae as a species distinct from E. silesiacus.
Shewmaker PL , Steigerwalt AG , Nicholson A , Carvalho MD , Facklam RR , Whitney A , Teixeira LM . J Clin Microbiol 2011 49 (7) 2676-9 Several of the more recently proposed new species of Enterococcus are nearly identical based on 16S rDNA sequence analysis and phenotypic traits. In the present study, DNA-DNA reassociation experiments, in conjunction with sequencing of the 16S rRNA and rpoB genes, provided evidence that "Enterococcus sanguinicola" and Enterococcus thailandicus actually represent the same species. In contrast, Enterococcus caccae and Enterococcus silesiacus, two other species with nearly identical 16S rRNA gene sequences were confirmed as separate species. |
Invasive pneumococcal infections among vaccinated children in the United States
Park SY , Van Beneden CA , Pilishvili T , Martin M , Facklam RR , Whitney CG , Active Bacterial Core surveillance team . J Pediatr 2009 156 (3) 478-483.e2 OBJECTIVE: Because 7-valent pneumococcal conjugate vaccine (PCV7) is highly efficacious, pneumococcal infections in vaccinated children raise concerns about immunologic disorders. We characterized a case series of US children in whom invasive pneumococcal infections developed despite vaccination. STUDY DESIGN: We reviewed invasive (sterile site) pneumococcal infections in children aged <5 years who had received ≥1 PCV7 dose as identified from October 2001 to February 2004 through national passive surveillance and the Centers for Disease Control and Prevention's Active Bacterial Core surveillance. Vaccine serotype infections were considered breakthrough cases; the subset of breakthrough cases occurring in children who completed an age-appropriate vaccination series were considered PCV7 failures. RESULTS: We identified 753 invasive infections; 155 infections (21%) were breakthrough cases, predominantly caused by serotypes 6B (n = 50, 32%) and 19F (n = 45, 29%). The proportion of breakthrough cases decreased with the increasing number of PCV7 doses received (P < .001, X(2) for linear trend). Children with co-morbid conditions accounted for 31% of breakthrough infections. Twenty-seven cases (4%) were classified as vaccine failures. Most failures (71%) occurred in children who were vaccinated according to catch-up schedules; 37% had co-morbid conditions. CONCLUSION: Invasive pneumococcal infections identified in vaccinated U.S. children were primarily caused by disease resulting from serotypes not covered with PCV7, rather than failure of the vaccine. Incomplete vaccination and co-morbid conditions likely contribute to breakthrough vaccine-type pneumococcal infections. |
Evaluation of three commercial broth media for pigment detection and identification of group B streptococci (GBS), Streptococcus agalactiae
Carvalho MD , Facklam R , Jackson D , Beall B , McGee L . J Clin Microbiol 2009 47 (12) 4161-3 Detection of GBS strains at various bacterial concentrations was evaluated using three pigment-producing broth media. At 10(3) CFU/ml, StrepB Carrot Broth(TM) (SBCB), Granada Instant Liquid Biphasic (IGLB), and Northeast Laboratory GBS Screening Medium (NEL-GBS) showed 100% detection but at the lower bacterial counts SBCB and IGLB were more sensitive than NEL-GBS after 24hrs. |
Genetic relationships deduced from emm and multilocus sequence typing of invasive Streptococcus dysgalactiae subsp. equisimilis and S. canis recovered from isolates collected in the United States
Ahmad Y , Gertz RE Jr , Li Z , Sakota V , Broyles LN , Van Beneden C , Facklam R , Shewmaker PL , Reingold A , Farley MM , Beall BW . J Clin Microbiol 2009 47 (7) 2046-54 Beta-hemolytic group C and G streptococci cause a considerable invasive disease burden and sometimes cause disease outbreaks. Little is known about the critical epidemiologic parameter of genetic relatedness between isolates. We determined the emm types of 334 Streptococcus dysgalactiae subsp. equisimilis isolates, and attempted emm typing of 5 Streptococcus canis isolates from a recent population-based surveillance for invasive isolates. Thirty-four emm types were observed, including one from S. canis. We formulated multilocus sequence typing (MLST) primers with six of the seven loci corresponding to the Streptococcus pyogenes MLST scheme. We performed MLST with 65 of the 334 surveillance isolates (61 S. dysgalactiae subsp. equisimilis isolates, 4 S. canis isolates) to represent each emm type identified, including 2 to 3 isolates for each of the 25 redundantly represented emm types. Forty-one MLST sequence types (STs) were observed. Isolates within 16 redundantly represented S. dysgalactiae subsp. equisimilis emm types shared identical or nearly identical STs, demonstrating concordance between the emm type and genetic relatedness. However, seven STs were each represented by two to four different emm types, and 7 of the 10 S. dysgalactiae subsp. equisimilis eBURST groups represented up to six different emm types. Thus, S. dysgalactiae subsp. equisimilis isolates were similar to S. pyogenes isolates, in that strains of the same emm type were often highly related, but they differed from S. pyogenes, in that S. dysgalactiae subsp. equisimilis strains with identical or closely similar STs often exhibited multiple unrelated emm types. The phylogenetic relationships between S. dysgalactiae subsp. equisimilis and S. pyogenes alleles revealed a history of interspecies recombination, with either species often serving as genetic donors. The four S. canis isolates shared highly homologous alleles but were unrelated clones without evidence of past recombination with S. dysgalactiae subsp. equisimilis or S. pyogenes. |
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