The accurate identification of the infecting species and the determination of its susceptibility to antimicrobial agents, given the large number of strains with atypical patterns, are crucial if patients with nocardiosis are to be successfully treated.

All the studied genes and their related ISs showed a clonal distribution. Imipenem resistance was probably provided by OXA-40 for the most part, while MBL- and OXA-23-encoding genes were absent in the studied population.

One hundred thirty-six isolates, 88 human and 48 environmental, that met the requirements to belong to the genus Paenibacillus were identified using a polyphasic taxonomic approach known as 16S rRNA plus phenotypic traits. Thirty-seven Paenibacillus species were identified; some had not been previously reported from clinical samples. The main species were P. pabuli (13 isolates), P. provencensis (11), P. phoenicis (9) and P. lautus (8). P. pabuli (11/13) and P. provencensis (8/11) were mainly environmental isolates, while P. phoenicis (9/9) and P. lautus (6/8) were mainly human isolates. Despite the difficulties in assigning to human Paenibacillus isolates a role as a pathogen or contaminant, here 25% of the isolates were involved in true infections, especially in those cases that affected abscesses, wound exudates, ocular infections and diverse fluids. In addition, 15 isolates were identified as 11 ‘Candidatus’ to a new species, all of them from human specimens except one that was obtained from laboratory air. The antimicrobial susceptibility testing showed 95.6% of isolates were resistant to ampicillin, 44% were resistant to cotrimoxazole, 20 to 30% were resistant to cefotaxime and vancomycin and 13% were resistant to rifampicin and erythromycin.

This study compares the identification, typing, and phylogenetic relationships of the most prevalent clinical Nocardia species in Spain, as determined via sequence analysis of their housekeeping genes gyrB and rpoB, with the results returned by the gold standard 16S rRNA method. gyrB and rpoB analyses identified Nocardia abscessus, N. cyriacigeorgica, N. farcinica, and the N. nova complex, species that together account for more than half of the human nocardiosis cases recorded in Spain. The individual discriminatory power of gyrB and rpoB with respect to intraspecies typing, calculated using the Hunter-Gaston discriminatory index (HGDI), was generally high (HGDI, 0.85 to 1), except for rpoB with respect to N. farcinica (HGDI, 0.71). Phylogenetically, different degrees of intra-and interspecies microheterogeneity were observed for gyrB and rpoB in a group of 119 clinical strains. A single 16S haplotype was obtained for each species, except for the N. nova complex (8 types), while gyrB and rpoB were more polymorphic: N. abscessus had 14 and 18 haplotypes, N. cyriacigeorgica had 17 and 12, N. farcinica had 11 and 5, and the N. nova complex had 26 and 29 haplotypes, respectively. A diversity gradient was therefore seen, with N. farcinica at the bottom followed by N. abscessus and N. cyriacigeorgica in the middle and N. nova complex at the top. The complexity of the N. nova complex is highlighted by its six variations in the GyrB 126 AAAPEH motif. gyrB sequencing (with or without rpoB sequencing) offers a simple means for identifying the most prevalent Nocardia species in Spanish medical laboratories and for determining the intraspecific diversity among their strains. Members of the genus Nocardia are ramified Gram-positive bacilli that normally live in dust, sand, soil, decaying vegetation, and stagnant water (1). To date, nearly 99 Nocardia species have been identified (see NCBI taxonomy for Nocardia, http://www.ncbi.nlm .nih.gov/Taxonomy/Browser/wwwtax.cgi?idϭ1817 and http://www .bacterio.cict.fr/n/nocardia.html), but this number undergoes constant modification. Some one-third of Nocardia species are known human pathogens, and new pathogenic species causing different clinical problems are constantly being discovered (2, 3). Infection occurs mainly via the respiratory tract, later disseminating to other locations, such as the central nervous system. Localized infection is caused by traumatic injury and gives rise to abscesses (4).Partial 16S rRNA gene sequencing is the gold standard for identifying Nocardia spp. (1). However, the conservation of 16S can be an obstacle to distinguishing between closely related species, such as those of the Nocardia nova complex (5, 6). To overcome this disadvantage and to establish phylogenetic relationships at the intra-and interspecies levels, other protein-encoding genes have been studied, such as the 65-kDa heat shock protein hsp65 (7), the essential secretory protein secA1 (8), gyrB, which is the ␤-subunit of DNA gyrase and a type II DNA topoisomerase (9), and rpoB, which is th...

The severe morbidity of human brucellosis is one of the main reasons for using molecular typing in the epidemiological surveillance of this worldwide zoonosis. Multiple-locus variable-number repeat analysis (MLVA-16), hypervariable octameric oligonucleotide fingerprinting (HOOF-print), and the differences in the single nucleotide polymorphisms (SNPs) (codons 1249 and 1309) of the DNA-dependent RNA polymerase ␤ subunit (rpoB) were used to type a human Brucella melitensis population (108 strains) collected from throughout Spain over 13 years. Eighty-six MLVA types (discriminatory index, 0.99) were detected, with a wide-ranging genetic similarity coefficient (

The soil-borne pathogen Nocardia sp. causes severe cutaneous, pulmonary, and central nervous system infections. Against them, co-trimoxazole (SXT) constitutes the mainstay of antimicrobial therapy. However, some Nocardia strains show resistance to SXT, but the underlying genetic basis is unknown. We investigated the presence of genetic resistance determinants and class 1–3 integrons in 76 SXT-resistant Nocardia strains by PCR and sequencing. By E test, these clinical strains showed SXT minimum inhibitory concentrations of ≥32:608 mg/L (ratio of 1:19 for trimethoprim: sulfamethoxazole). They belonged to 12 species, being the main representatives Nocardia farcinica (32%), followed by N. flavorosea (6.5%), N. nova (11.8%), N. carnea (10.5%), N. transvalensis (10.5%), and Nocardia sp. (6.5%). The prevalence of resistance genes in the SXT-resistant strains was as follows: sul1 and sul2 93.4 and 78.9%, respectively, dfrA(S1) 14.7%, blaTEM-1 and blaZ 2.6 and 2.6%, respectively, VIM-2 1.3%, aph(3′)-IIIa 40.8%, ermA, ermB, mefA, and msrD 2.6, 77.6, 14.4, and 5.2%, respectively, and tet(O), tet(M), and tet(L) 48.6, 25.0, and 3.9%, respectively. Detected amino acid changes in GyrA were not related to fluoroquinolone resistance, but probably linked to species polymorphism. Class 1 and 3 integrons were found in 93.42 and 56.57% strains, respectively. Class 2 integrons and sul3 genes were not detected. Other mechanisms, different than dfrA(S1), dfrD, dfrF, dfrG, and dfrK, could explain the strong trimethoprim resistance shown by the other 64 strains. For first time, resistance determinants commonly found in clinically important bacteria were detected in Nocardia sp. sul1, sul2, erm(B), and tet(O) were the most prevalent in the SXT-resistant strains. The similarity in their resistome could be due to a common genetic platform, in which these determinants are co-transferred.

The absence of rpoB mutations clearly related to rifampicin resistance in clinical B. melitensis strains reinforces the first-choice status of this antibiotic in the treatment of first brucellosis episodes, and demonstrates the usefulness of molecular screening for resistant genotypes. The absence of topoisomerase II-IV mutations, however, cannot rule out fluoroquinolone resistance due to the interplay of different mechanisms.

Species of the Burkholderia cepacia complex are associated with opportunistic infection in patients with cystic fibrosis. For years now, B. multivorans and B. cenocepacia have been the most frequently isolated species within the complex in such patients. However, between 2008 and 2012, the overall incidence of these species in Spain (17.7% and 12.5% respectively) was overtaken by that of B. contaminans (36.5%). The population structure of B. contaminans isolates from Spanish patients with cystic fibrosis was analysed using multilocus sequence typing and pulsed-field gel electrophoresis (PFGE). Three major known sequence types (ST102, ST404 and ST482) and a new one (ST771) were identified among 59 isolates. In addition, PFGE detected 17 pulsotypes. Susceptibility to antibiotics was examined using the Etest. Cotrimoxazole and ceftazidime were the most active antibiotics against B. contaminans, inhibiting growth in 88% and 86% of the isolates, respectively. In addition, this species showed less resistance to most of the antibiotics tested than did either B. multivorans or B. cenocepacia isolates recovered from similar Spanish patients.