Bacteria from the Burkholderia cepacia complex (Bcc) are capable of causing severe infections in patients with cystic fibrosis (CF). These opportunistic pathogens are also widely distributed in natural and man-made environments. After a 12-year epidemiological surveillance involving Bcc bacteria from respiratory secretions of Argentinean patients with CF and from hospital settings, we found six isolates of the Bcc with a concatenated species-specific allele sequence that differed by more than 3 % from those of the Bcc with validly published names. According to the multilocus sequence analysis (MLSA), these isolates clustered with the agricultural soil strain, Burkholderia sp. PBP 78, which was already deposited in the PubMLST database. The isolates were examined using a polyphasic approach, which included 16S rRNA, recA, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), DNA base composition, average nucleotide identities (ANIs), fatty acid profiles, and biochemical characterizations. The results of the present study demonstrate that the seven isolates represent a single novel species within the Bcc, for which the name Burkholderia puraquae sp. nov. is proposed. Burkholderia puraquae sp. nov. CAMPA 1040 (=LMG 29660=DSM 103137) was designated the type strain of the novel species, which can be differentiated from other species of the Bcc mainly from recA gene sequence analysis, MLSA, ANIb, MALDI-TOF MS analysis, and some biochemical tests, including the ability to grow at 42 °C, aesculin hydrolysis, and lysine decarboxylase and β-galactosidase activities.

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A total of 120 Burkholderia cepacia complex isolates collected during 2004 -2010 from 66 patients in two cystic fibrosis reference centers in Argentina were analyzed. Burkholderia contaminans was the species most frequently recovered (57.6%), followed by Burkholderia cenocepacia (15%), a species distribution not reported so far. The recA-PCR-based techniques applied to the B. contaminans isolates revealed that 85% of the population carried the recA-ST-71 allele. Our results showed the utility of BOX-PCR genotyping in analyzing B. contaminans diversity. This approach allowed us to address clonal transmission during an outbreak and the genetic changes occurring in infecting bacteria over the course of chronic infection. Burkholderia cepacia complex species are capable of causing chronic and often severe respiratory tract infections in cystic fibrosis (CF) patients and other types of infections in immunocompromised patients. Although many CF patients remain infected by these bacteria and yet stay relatively healthy for prolonged periods, others either have a severe decline in their pulmonary status or die shortly after the initial colonization (1). In Argentina, the first reports of B. cepacia complex bacteria infecting CF patients started around 1990. At that time, Burkholderia spp. were recovered sporadically and with a very low prevalence (Ͻ0.1%). The prevalence increased over the last decade from 0.2 to 3.6%, depending on the medical center. In early 2004, an outbreak involving main Argentine CF care centers occurred, and the proportion of patients from whom B. cepacia complex species were recovered ranged from 19 to 36% (2-4). Currently, through strict infection control procedures, the prevalence of Burkholderia spp. in local patients has decreased to approximately 10%. Recent worldwide surveillance studies concerning the distribution of B. cepacia complex species in CF patients have cited B. multivorans and B. cenocepacia as the most frequently recovered species. These species account for approximately 80% of the infected patients, and the prevalence of one or the other is geographically and temporally dependent (5-7). Unlike this worldwide situation, in Argentina a relatively high prevalence of B. contaminans followed by B. cenocepacia has been observed (3, 4). To our knowledge, no other geographical region has been reported in the literature to have such a high occurrence of B. contaminans infecting CF patients. In view of this particular scenario, coupled with the lack of biodiversity information available for B. contaminans species, we decided to study this local population by recA-PCR-based techniques and by repetitive element sequence-based PCR (rep-PCR) approaches. These methods allowed us to address the genetic diversity of B. contaminans isolates recovered during that outbreak along with the genetic changes occurring in the infecting bacteria over the course of a chronic infection.

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Background Pandoraea species are considered emerging pathogens in the context of cystic fibrosis (CF) and are difficult to identify by conventional biochemical methods. These multidrug resistant bacteria remain poorly understood particularly in terms of natural resistance, mechanisms of acquired resistance and impact on the prognosis of the disease and the lung function. Among them, Pandoraea sputorum has been previously described in few cases of CF patients from Spain, Australia, France and United States, underlining the need of more clinical data for a better knowledge of its pathogenicity. This is the first report relating to P. sputorum in a CF patient in Argentina.Case presentation Pandoraea sputorum was identified in a nine-year-old cystic fibrosis patient from Argentina, after treatment failure during an exacerbation. The isolates were successfully identified by combining molecular techniques based on 16S rRNA sequencing and mass spectrometry (MS) methods, after reassessing previous misidentified isolates by conventional methods. After first isolation of P. sputorum, patient’s clinical condition worsened but later improved after a change in the treatment. Although isolates showed susceptibility to trimethoprim–sulfamethoxazole and imipenem, in our case, the antibiotic treatment failed in the eradication of P. sputorum.ConclusionsAll combined data showed a chronic colonization with P. sputorum associated to a deterioration of lung function. We noted that the presence of P. sputorum can be underestimated in CF patients and MALDI-TOF MS appears to be a promising means of accurate identification of Pandoraea species.

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We investigated the genetic differentiation of five X-chromosome STR markers among five native South American Amerindian populations inhabiting three different areas of the Gran Chaco: Mocoví, Chorote, Wichí, Lengua, and Ayoreo. The observed genetic structure showed correspondence with geographic distribution more clearly than previous information obtained from autosomal STRs for the same samples. On the other hand, X-chromosome STR data did not agree with linguistic affinities. These markers proved to be informative for the study of the native populations of the Gran Chaco region.

The Wichí people from Chaco Province inhabit the region called Impenetrable Chaqueño, where the climatic conditions are extreme. Besides scarce communication with the main urban centers, the cultural patterns of the Wichí cause these communities to live in certain degree of isolation. The effect of this situation is an increased genetic differentiation from other populations, as it was observed through autosomal and Y chromosome markers. However, the genetic variation of X chromosome has not yet been fully analyzed. The patterns of allele distribution of different markers of X chromosome can be highly informative in comparative studies, because its special features make this chromosome a potential source to uncover ethnic differences. The aim of this study was to assess the variation of X chromosome present in the Wichí population living around Misión Nueva Pompeya, in Chaco Province, and to identify particular variation of X-repetitive markers (short tandem repeats, X-STRs) in Chaco Amerindians. We genotyped Wichí for 10 noncoding X-STRs and compared them with a Mocoví population and with published data on individuals coming from European immigration. We found high homozygote proportion and linkage disequilibrium values for the X chromosome in the Wichí population. The data showed the Wichí to be more distant from nonnative people than was the Mocoví population analyzed for comparison. We also found certain differences with Mocoví, possibly due to a higher genetic flow of the latter with nonnatives. A process of genetic drift seems to be enhanced by the social behavior of the Wichí, since they live apart from other native and nonnative groups. The geographic isolation and the extreme environmental conditions can also be considered as major factors contributing to the population differentiation. Although we found no new allele or undescribed variation, the whole pattern of variation for these markers gives the Wichí a particular population identity.