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Abstract: The frequency of finding of clindamycin-resistant anaerobic bacteria in clinical samples has doubled from 2008 to 2010 in Costa Rica. To determine whether this increase is due to dissemination of erm genes aided by tetQ elements, we analyzed 100 isolates of Bacteroides or Parabacteroides from a regional hospital, a national hospital, and the community. Antimicrobial susceptibilities were recorded with a broth micro-dilution method and erm genes were detected by PCR and Southern blotting. In addition, plasmid isolation and mating experiments were performed to clarify the location and mobility of the detected erm genes. Resistance to clindamycin was by far more frequent in the regional hospital (72%) than in the national hospital (29%) and the community (26%). Resistance to tetracycline was even more common, with the community (85%) outweighing the hospitals (71–72%). While MIC of clindamycin were higher in the hospitals than in the community (P < 0.05), the opposite was seen for tetracycline (P < 0.0001). Of the sought-after genes, only ermG (n = 2), ermA (n = 1), and ermF (n = 1) were detected in the hospitals and ermF in the community (n = 2). In opposition to the low frequency of finding of erm genes, 71% of the isolates were positive for tetQ. None of the detected genes were encoded on plasmids. Only three isolates from the hospitals transferred their erm genes laterally. By contrast, 13 hospital isolates and two community isolates transferred tetQ. Despite the widespread finding of tetracycline-resistant tetQ-positive bacteria, mobile erm genes were rare in our bacterial collection. We conclude that the detected erm genes are likely not included in typical conjugative transposons of Bacteroides and Parabacteroides. [Copyright &y& Elsevier]

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Because of limitations in infrastructure, the aetiology of infections caused by anaerobic bacteria is seldom determined in clinical laboratories of developing countries. This study reports on the identification of 1010 anaerobic bacterial isolates collected between 1999 and 2008 in a major Costa Rican hospital with the use of two commercial phenotypic systems (RapID 32A and API 20A). Approximately 60% of the isolates were Gram-positive and, among the 35 species of Gram-positive bacteria found, the genera Clostridium, Propionibacterium and Eggerthella, and anaerobic cocci predominated. Twenty eight species were found among 395 isolates of Gram-negative bacteria. Species of Bacteroides were very frequent, followed by species of Prevotella, Veillonella, Fusobacterium and Porphyromonas. [ABSTRACT FROM AUTHOR]

Microbial contamination of fuel has been the cause of several problems in transportation and storage of these products. Due to the lack of previous studies related to these problems in Costa Rica, bacterial quality was evaluated biannually in automotive fuels stored in the four oil distribution facilities of the Costa Rican Petroleum Refinery (RECOPE). In 12 oil storage tanks, for a total of 96 samples, mesophilic, heterotrophic aerobic/facultative counts (ASTM D6974-04) and identification of bacteria presented in regular gas, premium gas and diesel from the bottom and superior part of the tanks were done; in the samples containing an aqueous phase, sulfate reducing bacteria (SRB) were also quantified by the most probable number technique (MPN), according to the ASTM D4412-84 standard. The higher contamination was shown at the bottom of the tanks (populations up to 104 UFC/l), especially if there was accumulated water, in which case populations reached 108 UFC/l. The most contaminated fuel was diesel (counts up to 104 UFC/l), whereas the less contaminated was premium gas. The less contaminated fuels were from the facilities of La Garita and Barranca, whereas the most contaminated were from Ochomogo. Nevertheless, the quantified populations did not cause significant alteration in quality physicochemical parameters in the samples analyzed. A total of 149 bacterial strains were isolated, 136 (91.3%) Gram positive and 13 (8.7%) Gram negative. The most frequent genera were Staphylococcus (24.0%), Micrococcus (21.9%), Bacillus (18.8%) and Kocuria (11.5%) among Gram positive bacteria and Pseudomonas (7.3%) among Gram negative bacteria. The majority of these genera have been found as fuel contaminants or even as degraders of this kind of products; nevertheless, some species for which their appearance or growth in hydrocarbons have not been described were found with low frequencies. SRB were present in counts up to 105 MPN/l in 42.9% of water containing samples (including all from diesel tanks), indicating biocorrosion processes risk in fuel transport and storage systems. From the findings in this study it is recommended to give a frequent maintenance to fuel containers, based on continuous drainage and removal of accumulated water, antimicrobial agent addition and microbial quality monitoring in country's fuels. [ABSTRACT FROM AUTHOR]

An innovative approach based on the combination of spectroscopy and traceology was used in order to analyse iron ore mirrors excavated at the Sojo site (Chibcha area, present-day Costa Rica) in the northern Pacific region of Costa Rica (AD 300 to AD 500–600). Such mirrors were prestigious artefacts related to power, shamanism and divination during the Classic Period in the Maya area. Stone bases, adhesives and tesserae were characterised using FT-IR, SEM/EDX and Raman Spectroscopy, as well as X-Ray Fluorescence (XRF) and the techniques used in their manufacture were elucidated using traceology. Similar materials were found to have been used for all the bases, tesserae, adhesives and coatings of the different mirrors. Furthermore, two tessera-shaped fragments were most probably part of a composite mirror, manufactured by sticking hematite nodules onto stone tesserae using a clay mixed with an organic binder. Chert and obsidian tools were used to make, respectively, perforations and edges on all mirror bases, and the two main types of abrasion of the base surfaces were found to have been made with basalt or limestone. These analyses indicate a probable Maya origin as their manufacturing traces distinguish them from Teotihuacan mirrors. • Analytical chemistry and traceology indicate a probable Maya origin of the mirrors. • Similar materials were found in all the bases, tesserae, adhesives and coatings. • Adhesives and coatings were made of a dickite clay including an organic material. • Chert and obsidian tools were used to make perforations and edges on all mirror bases. • Two main types of abrasion were detected on the base surfaces. [ABSTRACT FROM AUTHOR]