Tetracycline resistance transmission in Campylobacter is promoted at temperatures resembling the avian reservoir.

Campylobacter is the causal agent of campylobacteriosis in humans, a self-limiting gastroenteritis. Campylobacteriosis is a zoonosis, commonly transmitted from contaminated chicken meat by either direct consumption or cross contamination during food manipulation. Presence of plasmids encoding for resistance to antibiotics such as tetracycline is common among Campylobacter isolates. In this report, we studied the effect of the temperature in the conjugation frequency of several tet(O) carrying plasmids, providing tetracycline resistance to the recipient cells. The conjugation frequency from donor cells carrying three previously characterized plasmids (pCjA13, pCjA9 and pTet) and from two clinical isolates was determined. Two temperatures, 37 and 42 °C, mimicking the conditions encountered by C. jejuni in the human and broiler chicken gastrointestinal tracts, respectively, were assessed. Our results clearly indicate that the conjugation process is promoted at high temperature. Accordingly, the transcriptional expression of some putative conjugative apparatus genes is thermoregulated, being induced at 42 °C. The two plasmids present in the clinical isolates were sequenced and assembled. Both plasmids are highly related among them and to the pTet plasmid. The high identity of the genes putatively involved in the conjugation process among the plasmids is in agreement with the similar behavior regarding the temperature dependency of the conjugative process. This report suggest that conjugation of plasmids carrying antibiotic resistance genes occurs preferentially at temperatures that resemble the gastrointestinal tract of birds, the main reservoir of C. jejuni.

An improved and versatile methodology to quantify biofilms formed on solid surfaces and exposed to the air-liquid interphase.

To study pellicle formation, a new method has been developed to quantify biofilm formed on solid surfaces and exposed to air-liquid interphase. It is a versatile system since different adherent material surfaces might be tested. The methodology is a robust and reproducible approach to quantify biofilm.

[Iatrogenic hyperthyroidism. Report of an outbreak]. / Hipertiroidismo iatrógeno. A propósito de un brote epidémico.

The clinical observation of a series of 30 patients (age 29.6 +/- 9.8 years, 29 females and 1 male) who were remitted for evaluation of a thyroid dysfunction with a decrease in TSH and free thyroxin with clinical symptoms of hyperthyroidism and absence of goiter or exophthalmous is presented. Most of the patients (90%) had no family or personal history of previous thyroid disease. Anamnesis demonstrated the previous ingestion of uncommercialized prepared weight losers, dispensed in different areas off the pharmacy offices. Seventy-three percent of the patients had received the treatment from the same source (prescriber). In most of the cases (28 out of 30) normalization was observed in thyroid function tests. The demonstrated inefficacy of this medication as well as the health care importance of the problem are discussed.