[Species diversity of non-tuberculous mycobacteria isolated from aquatic environments of General Pico city, Province of La Pampa (Argentina)]. / Diversidad de especies de micobacterias no tuberculosas aisladas en ambientes acuáticos de la ciudad de General Pico, La Pampa, Argentina.

Non-tuberculous mycobacteria (NTM) are studied not only for their importance as emerging opportunistic pathogens but also for their applications in biotechnology and bioremediation. Our aim was to determine the occurrence and diversity of mycobacteria in different aquatic habitats of General Pico city, Province of La Pampa. The percentage of samples with positive cultures for mycobacteria were the following: 37.5% recovered from the water supply distribution system; 32.6% from the aquifer that supplies water to the distribution system; 36.8% from rain water; 53.1% from the two wetlands in the area of influence; 80% from indoor swimming pools; and 33.3% from water fountains in downtown public squares. Of the 90 NTM isolates, 8.9% could not be identified at the species level with any of the used methods, phenotypic tests and molecular methods. Mycobacterium fortuitum and Mycobacterium gordonae were the most frequently isolated species. Some of the identified species such as, M. fortuitum, M. gordonae, M. intracellulare, M. vaccae, M. lentiflavum and M. nonchromogenicum, have been reported in cases of mycobacteriosis in Argentina. Mycobacteria with values higher than 0.8mg/ml of residual active chlorine were not recovered from the drinking water supply network, whereas in the swimming pools the presence of up to 1.5mg/l was not a constraint. Based on our results, the presence of mycobacteria in aquatic environments is close to 35% and their occurrence and diversity is affected both by contact with man and his activities as well as by the existence of animal life.

Evaluation of the galactogogue effect of silymarin on mothers of preterm newborns (<32 weeks).

Hypogalactia has a relative high frequency in women having delivered preterm infants, who often have difficulties in maintaining a sufficient production of milk for their infants' needs over prolonged periods of time. Recent studies have shown a potential galactogogue effect of silymarin on milk production in animal models (cows and rats) and in humans (mothers of term newborns); nonetheless, none of the studies conducted on humans consisted of double-blind randomized clinical trials and no data are available concerning mothers who delivered preterm infants. The aim of our study was to assess the efficacy of silymarin (BIO-C®) as galactogogue and its tolerability in mothers who delivered preterm infants. We enrolled 50 mothers at 10±1 days post-partum who had delivered infants at ® and placebo arms. No adverse events were observed in the 2 arms among mothers and infants, and silymarin and its metabolites were not detectable in the analyzed human milk samples. Further investigation on specific patient groups affected by hypogalactia, defined according to stricter criteria, should be planned to assess the efficacy of the product in increasing milk production.

Exploring the cellulolytic activity of environmental mycobacteria.

Although studies on non-tuberculous mycobacteria have increased in recent years because they cause a considerable proportion of infections, their cellulolytic system is still poorly studied. This study presents a characterization of the cellulolytic activities of environmental mycobacterial isolates derived from soil and water samples from the central region of Argentina, aimed to evaluate the conservation of the mechanism for the degradation of cellulose in this group of bacteria. The molecular and genomic identification revealed identity with Mycolicibacterium septicum. The endoglucanase and total cellulase activities were assessed both qualitatively and quantitatively and the optimal enzymatic conditions were characterized. A specific protein of around 56 kDa with cellulolytic activity was detected in a zymogram. Protein sequences possibly arising from a cellulase were identified by mass spectrometry-based shotgun proteomics. Results showed that M. septicum encodes for cellulose- and hemicellulose-related degrading enzymes, including at least an active ß-1,4 endoglucanase enzyme that could be useful to improve its survival in the environment. Given the important health issues related to mycobacteria, the results of the present study may contribute to the knowledge of their cellulolytic system, which could be important for their ability to survive in many different types of environments.

Utilization of molecular and conventional methods for the identification of nontuberculous mycobacteria isolated from different water sources.

Background: The environment is the nontuberculous mycobacteria (NTM) reservoir, opportunistic pathogens of great diversity and ubiquity, which is observed in the constant description of new species capable of causing infection. Since its introduction, molecular methods are essential for species identification. Most comparative studies between molecular and conventional methods, have used isolated strains from clinical samples. Methods: The aim of this study was to evaluate the usefulness of molecular methods, especially the hsp65-PRA (PCR-Restriction Enzyme Analysis), and biochemical tests in the identification of NTM recovered from water of different origins, using the sequencing of 16S rRNA and hsp 65 genes as assessment methods of the previous ones. Species identification was performed for all 56 NTM isolates what were recovered from 32 (42.1%) positive water samples, using conventional phenotypic methods, hsp65-PRA, partial sequencing of 16S rRNA and sequencing of hsp 65 genes. Results: Phenotypic evaluation and hsp65-PRA were concordant with 23 (41.1%) isolates. Also, the PRA was concordant with 16 (28.6%) and 27 (48.2%) isolates, with the partial sequencing of 16S rRNA and sequencing of hsp 65 genes, respectively. It is considered that the 19.6% (n = 11) could not be identified. Conclusion: Identification of NTM environmental isolates to the species level, especially when they are pigmented and fast-growing, both the analysis of the restriction patterns obtained by PRA and the sequencing of the 16S rRNA and hsp 65 genes are insufficient by themselves. Although they are demanding and time-consuming, biochemical tests are very useful to support data obtained by molecular methods.

Effects of Holder pasteurization on the protein profile of human milk.

BACKGROUND: The most widespread method for the treatment of donor milk is the Holder pasteurization (HoP). The available literature data show that HoP may cause degradation of some bioactive components. The aim of this study was to determine the effect of HoP on the protein profile of human milk (HM) using a GeLC-MS method, a proteomic approach and a promising technique able to offer a qualitative HM protein profile. METHODS: HM samples were collected by standardized methods from 20 mothers carrying both preterm and term newborns. A aliquot of each sample was immediately frozen at -80 °C, whilst another one was Holder pasteurized and then frozen. All samples were then analyzed by GeLC-MS. The protein bands of interest were excised from the gel, digested with trypsin and identified by nano-HPLC-MS/MS analysis. RESULTS: The protein profile before and after HoP showed qualitative differences only in 6 samples out of 20, while in the remaining 14 no detectable differences were found. The differences interested only colostrums and transitional milk samples and regarded the decrease of the electrophoretic bands corresponding to alpha and beta-casein, tenascin, lactoferrin and immunoglobulin. CONCLUSIONS: In the majority of samples, HoP did not cause any modification, thereby preserving the biological activity of HM proteins.