[Campylobacter spp.: prevalence and pheno-genotypic characterization of isolates recovered from patients suffering from diarrhea and their pets in La Pampa Province, Argentina]. / Campylobacter spp.: prevalencia y caracterización feno-genotípica de aislamientos de pacientes con diarrea y de sus mascotas en la provincia de La Pampa, Argentina.

The prevalence of Campylobacter spp. was investigated in 327 patients suffering from diarrhea and in 36 animals (dogs, cats and chickens) owned by the patients that presented infection by Campylobacter in Santa Rosa, La Pampa, Argentina. Campylobacter spp. was isolated in 50/327 patients and in 12/36 animals, being Campylobacter jejuni the most common species. Resistance to ciprofloxacin (65 %) and tetracycline (32 %) was found among 35 isolates of human origin studied. Seven genetic subtypes were observed among 13 C. jejuni isolates by pulsed field gel electrophoresis. Two subtypes grouped isolates belonging to patients and their respective dogs whereas another subtype grouped one isolate of human origin and two isolates from the patient's chickens. The results of this investigation highlight the need to strengthen surveillance of Campylobacter spp. not only in poultry, which is recognized as the main reservoir, but also in pets, which were shown to be asymptomatic carriers of the pathogen.

Normally occurring human anti-GM1 immunoglobulin M antibodies and the immune response to bacteria.

Anti-GM(1) antibodies of the immunoglobulin M (IgM) isotype are normal components of the antibody repertoire of adult human serum. Using a sensitive high-performance thin-layer chromatography (HPTLC) immunostaining assay, we found that these antibodies were absent in the umbilical vein and children <1 month of age but could be detected after 1 month of age. Although most of the children older than 6 months of age were positive, there were still a few negative children. The appearance of anti-GM(1) IgM antibodies showed a perfect concordance with two well-characterized antibacterial antibodies, anti-Forssman and anti-blood group A, which indicates a similar origin. We also studied IgM reactivity with lipopolysaccharides (LPSs) from gram-negative bacteria isolated from stool samples from healthy babies and from Escherichia coli HB101 in serum from individuals of different ages. We found a positive reaction with both LPSs in all the children more than 1 month of age analyzed, even in those that were negative for anti-GM(1) antibodies. Anti-GM(1) IgM antibodies were purified from adult serum by affinity chromatography and tested for the ability to bind LPSs from different bacteria. This highly specific preparation showed reactivity only with LPS from a strain of Campylobacter jejuni isolated from a patient with diarrhea. We conclude that normally occurring IgM antibodies are generated after birth, probably during the immune defense against specific bacterial strains.