Achromobacter spp. are opportunistic pathogens increasingly recovered from adult patients with cystic fibrosis (CF). We report the characterization of 122 Achromobacter spp. isolates recovered from 39 CF patients by multilocus sequence typing, virulence traits, and susceptibility to antimicrobials. Two species, A. xylosoxidans (77%) and A. ruhlandii (23%) were identified. All isolates showed a similar biofilm formation ability, and a positive swimming phenotype. By contrast, 4·3% and 44·4% of A. xylosoxidans and A. ruhlandii, respectively, exhibited a negative swarming phenotype, making the swimming and swarming abilities of A. xylosoxidans significantly higher than those of A. ruhlandii. A. xylosoxidans isolates from an outbreak clone also exhibited significantly higher motility. Both species were generally susceptible to ceftazidime, ciprofloxacin, imipenem and trimethoprim/sulphamethoxazole and there was no significant difference in susceptibility between isolates from chronic or sporadic infection. However, A. xylosoxidans isolates from chronic and sporadic cases were significantly more resistant to imipenem and ceftazidime than isolates of the outbreak clone.
Knowledge of the epidemiology of Streptococcus agalactiae in Portugal is limited: therefore, the present study aimed to investigate the carriage rate of S. agalactiae among Portuguese women of reproductive age and the prevalence of antibiotic resistance, as well as to perform a molecular characterization of the clinical isolates. S. agalactiae was recovered from 6.2% of 4269 women during the period 2005-2007, with a predominance of capsular genotypes III (35%), V (33%), Ia (16%) and II (10%) in a sample of 100 isolates. To our knowledge, this is the first report of the S. agalactiae colonization rate in Portugal determined according to CDC guidelines. All isolates were susceptible to penicillin and vancomycin, whereas resistance to clindamycin and erythromycin was detected in 10% and 19% of isolates, respectively. Among the 19 erythromycin-resistant isolates, ten (53%) displayed the constitutive MLS B phenotype (conferring highlevel resistance to macrolides), eight (42%) had the inducible MLS B , and the M phenotype accounted for one isolate (5%). erm methylase genes were exclusively associated with MLS B phenotype isolates, whereas the M phenotype was a result of the presence of mefA.Multilocus sequence typing analysis of the genetic relatedness among isolates presenting resistance to erythromycin demonstrated a novel association between erythromycin resistance and the subtype III-1/ST-19 genetic clone family.
A chromobacter is an emerging pathogen in cystic fibrosis (CF) patients, but accurate species identification of isolates is difficult. Most Achromobacter clinical isolates are designated as Achromobacter xylosoxidans; however, the commonly used phenotypic tests are not reliable (1-3). Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis is used in clinical microbiology laboratories as an emerging technology for bacterial species identification (4-8). Genotypic methods have also been developed for Achromobacter species. The amplification of an inner fragment of the bla OXA-114 gene has been proposed for A. xylosoxidans identification (9). Furthermore, the presence of bla , bla , and bla OXA-243 has been detected in Achromobacter ruhlandii, Achromobacter dolens, and Achromobacter insuavis, respectively (2, 3). Multilocus sequence typing (MLST) schemes that increase the accuracy of the characterization and identification of Achromobacter strains and species have also been developed (10,11). This study compares the identification of Achromobacter species from CF patients by bla OXA-114 gene sequencing, MLST, and MALDI-TOF MS.Twenty-eight archived isolates that had been collected between 2003 and 2008 from 16 CF patients attending two reference centers in Rio de Janeiro, Brazil, were included. The isolates were identified as A. xylosoxidans by 16S rRNA gene sequencing (12, 13); bla OXA-114-like gene amplification and sequencing were performed as described by Turton et al. (9). MLST analysis by sequencing of seven housekeeping genes (nusA, rpoB, eno, gltB, lepA, nuoL, and nrdA) was performed as described previously (11). Allelic profiles and sequence types (STs) were analyzed according to the PubMLST databases (http://pubmlst.org/achromobacter). MALDI-TOF MS identification was performed with a Microflex LT instrument (Bruker Daltonics, GmbH, Germany) using FlexControl 3.0 software (Bruker Daltonics). Scores of Ն2.0 indicated species-level identification, scores of 1.7 to 1.9 indicated genuslevel identification, and scores of Ͻ1.7 indicated no reliable identification (14, 15).Positive bla OXA-114 amplification was obtained for 26 isolates. In 17 isolates, amplicons showed 99 to 100% identity with the bla OXA-114 reference sequence. In 9 isolates, identified as A. ruhlandii, sequences displayed 99% identity with bla OXA-258 . Two isolates (isolates 4530 and 7393) were negative for bla OXA . As observed by Papalia et al. (2), in our study not only A. xylosoxidans but also A. ruhlandii yielded positive amplification for the A. xylosoxidans species-specific marker bla . Amplification of the inner fragment without sequence analysis, as initially described by Turton et al. (9), thus may result in the misidentification of some Achromobacter species; by this criterion, we would have identified 26 isolates instead of 17 as A. xylosoxidans. MALDI-TOF MS identified 89% of the isolates (25/28 isolates) as A. xylosoxidans, while 7% (2/28 isolates) were identified at the probable ge...
Acinetobacter spp. are important healthcare pathogens, being closely linked to antibiotic resistance and outbreaks worldwide. Although such species are rarely observed in patients with cystic fibrosis (CF), we describe the characteristics of 53 strains of Acinetobacter spp. isolated from the sputum of 39 Brazilian patients with CF. The species distribution was A. baumannii (n = 29), A. pittii (n = 13), A. nosocomialis (n = 8), A. seifertii (n = 1), A. soli (n = 1) and A. variabilis (n = 1) determined by partial rpoB gene sequencing. Sixteen strains (10 A. baumannii, 3 A. pittii and 3 A. nosocomialis) were multidrug-resistant (MDR) by disk diffusion test (30%) and eight MDR carbapenem-resistant A. baumannii strains harboured the bla OXA-23-like oxacillinase gene. Thirty-three sequence types (STs) were identified by multilocus sequence typing of which eight were novel (A. baumannii: 843, 844, 845, 847, 848; A. pitti: 643; A. nosocomialis: 862 and A. seifertii: 846); six STs (2 A. baumannii, 3 A. pittii and 1 A. nosocomialis) were found in more than one patient. Four strains of A. baumannii were assigned to two common clonal complexes (CCs), namely, CC1 (ST1, ST20 and ST160), and CC79 (ST79). This study underlines the extensive species diversity of Acinetobacter spp. strains in CF lung infections which may present difficulties for therapy due to significant antimicrobial resistance.
Achromobacter species are being increasingly isolated from the respiratory tract of cystic fibrosis patients. Recent reports indicate that Achromobacter ruhlandii is a potential human pathogen in cystic fibrosis-related infections. Here we report the draft genome of four A. ruhlandii strains isolated from cystic fibrosis patients in Brazil. This report describes A. ruhlandii as a potential opportunistic pathogen in cystic fibrosis and provides a framework to for additional enquires into potential virulence factors and resistance mechanisms within this species.
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