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Shiga-toxin producing Escherichia coli (STEC) is the etiologic agent of acute diarrhea, dysentery, and hemolytic-uremic syndrome (HUS). There is no approved vaccine for STEC infection in humans, and antibiotic use is contraindicated, as it promotes Shiga toxin production. In order to identify STEC-associated antigens and immunogenic proteins, outer membrane proteins (OMPs) were extracted from STEC O26:H11, O103, O113:H21, and O157:H7 strains, and commensal E. coli strain HS was used as a control. SDS-PAGE, two-dimensional-PAGE analysis, Western blot assays using sera from pediatric HUS patients and controls, and matrix-assisted laser desorption ionization–tandem time of flight analyses were used to identify 12 immunogenic OMPs, some of which were not reactive with control sera. Importantly, seven of these proteins have not been previously reported to be immunogenic in STEC strains. Among these seven proteins, OmpT and Cah displayed IgG and IgA reactivity with sera from HUS patients. Genes encoding these two proteins were present in a majority of STEC strains. Knowledge of the antigens produced during infection of the host and the immune response to those antigens will be important for future vaccine development.

To understand the etiology of moderate-to-severe diarrhea among children in high mortality areas of sub-Saharan Africa and South Asia, we performed a comprehensive case/control study of children aged

APPLICATION OF COPPER BACTERICIDAL PROPERTIES IN MEDICAL PRACTICE Copper is essential for cell metabolism in animals and plants and thus for life. Along centuries, copper has been identified as a metal containing antimicrobial properties. In recent years, laboratory assays and clinical studies have revealed that surfaces of metallic copper or its alloys, containing at least 70% copper, eliminate in a few hours several pathogenic organisms including bacterial strains associated with nosocomial infections, influenza virus, HIV, and fungi such as Candida albicans . In March 2008, the American Environmental Protection Agency (EPA), supported by scientific evidence gathered to date, registered copper as the first and only metal with antimicrobial properties. We herein review certain mechanisms proposed for the antibacterial, antiviral and antifungal activity of copper. We also discuss in vitro and clinical efficacy studies developed world wide and in Chile, focusing on bactericidal activity of copper surface areas in comparison to materials typically used in hospital environments such as stainless steel and polymers. Scientific evidence gathered to date, consistently shows that the use of copper surface areas in high contact critical points in hospitals, significantly reduces environmental bacterial load. This is associated with a decreased risk of pathogen transmission to patients and represents therefore an interesting complement to infection control programs. Normal 0 21 false false false ES X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

Adherence to epithelial cells by specific adhesins is a characteristic of Shiga toxin-producing Escherichia coli (STEC) strains. The eae-encoded protein intimin is the main adhesin implicated in intestinal colonization in vivo. We recently showed that STEC strains isolated in Chile displayed a wide variety of adhesins; here we demonstrate that some of these STEC strains are eae-negative and still adhere to epithelial cells at a level 100-fold higher than enterohaemorrhagic E. coli (EHEC) O157 : H7 prototype strain EDL933. This phenotype is associated with the presence of adherence factors different from the intimin protein. Subtractive hybridization between EHEC EDL933 and STEC eae-negative strain 472-1 was used to identify regions implicated in adhesion. In addition to the saa gene, we identified 18 specific genes in STEC 472-1, 16 of which had nucleotide identity to Salmonella ST46 phage genes; the two remaining ones shared identity to a gene encoding a hypothetical protein of uropathogenic E. coli. The DNA sequence of the STEC 472-1 psu-int region identified five open reading frames with homology to phage genes. We constructed mutant strains in the saa gene and the psu-int region to study the participation of these genes in the adherence to epithelial cells and our results demonstrated that STECDeltasaa and STECDeltapsu-int mutants displayed a 10-fold decrease in adherence as compared to the STEC 472-1 wild-type strain. Overall, our results suggest that STEC strain 472-1 adheres to epithelial cells in an eae-independent matter and that saa and psu-int participate in this adhesion process.

We designed a multiplex PCR for the detection of all categories of diarrheagenic Escherichia coli . This method proved to be specific and rapid in detecting virulence genes from Shiga toxin-producing ( stx 1 , stx 2 , and eae ), enteropathogenic ( eae and bfp ), enterotoxigenic ( stII and lt ), enteroinvasive ( virF and ipaH ), enteroaggregative ( aafII ), and diffuse adherent ( daaE ) Escherichia coli in stool samples.

Human caliciviruses caused 45% of 55 gastroenteritis outbreaks occurring in Santiago, Chile, during 2000–2003. Outbreaks affected ≤99 persons, occurred most commonly in the home, and were associated with seafood consumption. Thirteen outbreak strains sequenced were noroviruses, including 8 GII, 2 GI, and 3 belonging to a novel genogroup.

Shiga toxin-producing Escherichia coli are emerging as a significant source of food-borne infectious disease all over the world. Illness caused by Shiga toxin-producing E. coli can range from self limited, watery diarrhea to life-threatening manifestations such as hemorrhagic colitis, hemolytic uremic syndrome or thrombotic thrombocytopenic purpura and death. Shiga toxin-producing E. coli can potentially enter the human food chain from a number of animal sources, most commonly by contamination of meat with feces or intestinal contents after slaughter or cross-contamination of unpasteurized milk products. Because of the low infectious dose of the O157:H7 Shiga toxin-producing E. coli strain, laboratory diagnosis of Shiga toxin-producing E. coli in food samples has developed a great importance. This review will focus on the microorganism, giving priority to illness prevention and Shiga toxin-producing E. coli detection in food.

Several live oral vaccines (polio, bovine rotavirus, CVD 103-HgR cholera) are less immunogenic in developing than in industrialized countries. It was hypothesized that proximal small bowel bacterial overgrowth (common in children in less developed countries but rare in industrialized settings) diminishes the vibriocidal antibody response to CVD 103-HgR. In total, 202 fasting Santiago schoolchildren aged 5-9 years had lactulose breath H 2 tests to detect proximal small bowel bacteria 1 day before ingesting CVD 103-HgR. Florid small bowel overgrowth was observed in 10 (5.6%) of 178 analyzable children. In children with florid overgrowth, vibriocidal seroconversion differed little from other children (60% vs. 67%), but the geometric mean titer was lower (160 vs. 368; P = .25). By logistic regression, increased peak breath H 2 at small bowel time points was associated with diminished seroconversion (P = .04), as was the interaction of H 2 value and weight (children >25 kg had lower seroconversion rates among subjects with heaviest overgrowth).

Live oral cholera vaccine CVD 103-HgR is well-tolerated and immunogenic when administered to adults, school age children and preschool children in a single 5 x 10(9) colony-forming unit dose. Because elicitation of immune responses after administration of a single dose is exceptional for any oral vaccine in any age group, CVD 103-HgR was used as a probe to investigate the clinical acceptability, practicality and immunogenicity of this vaccine in infants and toddlers 3 to 17 months of age.The study was undertaken successively in 12- to 17-month-olds (n = 104), 7- to 11-month-olds (n = 106) and 3- to 5-month-olds (n = 102). One-half of the subjects were randomly allocated to receive vaccine and the other one-half to receive placebo, in double blind fashion. After 2 weeks of double blind follow-up, all subjects received a dose of vaccine. Vibriocidal antibody titers were measured on coded sera collected at baseline and 2 weeks after each dosing. The buffered vaccine "cocktail" had a volume of 100 ml; subjects who ingestedor =70 ml were considered fully vaccinated.Only 37% of subjects overall (25% of 3- to 5-month-olds) ingestedor =70 ml of the cocktail. The vaccine was well-tolerated with no significant differences in the rate or severity of adverse reactions after ingestion of vaccine vs. placebo. Seroconversion after ingestion of a single dose of CVD 103-HgR was similar in fully vaccinated subjects (66%) and in those who ingested a smaller fraction of the vaccine cocktail (63%). Of subjects who ingested two doses, 5 of 118 excreted vaccine organisms on Day 7 after the first dose vs. 0 of 118 after the second dose.Single dose oral CVD 103-HgR is well-tolerated and immunogenic in infants even when a partial dose is ingested. The buffered vaccine cocktail that is readily imbibed by older children is not appealing to young infants, and improved vaccine formulations and delivery vehicles for immunizing infants must be sought.

Rectal swabs were collected from Antarctic fur seal pups Arctocephalus gazella at Cape Shirreff, South Shetland Islands, and analyzed for the presence of anthropogenic pathogens. Two of the 33 pups tested positive for enteropathogenic Escherichia coli (EPEC). These samples are the first records of EPEC in Antarctic wildlife and suggest that more needs to be done to protect the Antarctic fauna from exotic anthropogenic pathogens.

We compared the incidence of nasopharyngeal colonization by Streptococcus pneumoniae , the serotypes causing mucosal and invasive diseases, and the antibiotic resistance of these strains in patients admitted to three large hospitals and children attending day care centers in two Chilean cities (Santiago and Temuco). The populations in both cities were similar in ethnic background, socioeconomic status, family size, and access to medical care. Significant differences in nasopharyngeal colonization rates, in serotypes causing infections, and in antibiotic resistance were found between the two cities. In children 0 to 2 years of age, 42% were colonized with S. pneumoniae in Santiago compared to 14% in Temuco. A total of 41 serotypes were identified in both Chilean cities studied. Six serotypes were found only in Santiago; 14 serotypes were found only in Temuco. Antibiotic-resistant serotypes 6A, 6B, 14, 19F, and 23F were detected only in Santiago. We show that important differences in the incidence of nasopharyngeal carriage, infection, and S. pneumoniae serotypes can exist in similar populations in different areas of the same country. Our findings are relevant for prevention strategies, antibiotic usage, and vaccine design.

BACKGROUND Shigella sonnei gastroenteritis improves clinically and microbiologically with antibacterial treatment; however choosing a useful drug is a universal challenge because of in vitro susceptibility of S. sonnei frequently evolves to be resistant. OBJECTIVE To evaluate in vitro susceptibility of S. sonnei strains isolated from patients attending at the Chilean Region Metropolitana and to know the evolution that resistant patterns of S. sonnei have experienced. MATERIAL In this study, the antimicrobial susceptibility profile of 277 isolates of Shigella sonnei was compared. The analyzed periods of time were: period I (1995-1997) 85 strains; period II (2004-2006) 92 strains and period III (2008-2009) 100 strains, in Santiago, Chile. The method performed to analyze susceptibility patterns was the disc diffusion (Kirby-Bauer). RESULTS The strains showed rates of resistance to ampicillin: period I, 85.8%; period II, 53.3%; period III, 100%, trimethoprim/sulfamethoxazole: period I, 50.5%; period, II 46.7%; period III, 100%, chloramphenicol: period I, 36.4%; period II, 12%; period III, 100% and tetracycline: period I, 38.8%; period II, 30.4%; period III, 100%. 98.9% of the strains showed susceptibility to quinolones. Significant differences were observed in patterns of antimicrobial resistance for both individuals and for multidrug resistance (≥ 3 antimicrobials) in the three periods (p < 0.001, χ2 test). Of all resistant strains, 17% were resistant to 1 or 2 antibiotics, while 65.7% showed a pattern of multidrug resistance; 100% of the period III strains presented multidrug resistance. CONCLUSION These results showed the temporal resistance dynamics of S. sonnei circulating strains in the Chilean Region Metropolitana. Due to the endemic behavior of shigellosis in Chile, it is urgent to maintain permanent surveillance of antimicrobial resistance profiles to improve both prevention and treatment of shigellosis.

We previously demonstrated the immunogenicity and tolerability of the serogroup B meningococcal vaccine, 4CMenB (Bexsero®), in 11−17 y-olds randomized to receive 1, 2, or 3 doses at 1, 2, or 6 mo intervals. Participants in this extension study provided an additional blood sample 18−24 mo after last vaccine dose, to assess persistence of serum bactericidal activity with human complement (hSBA), and to compare with age-matched 4CMenB-naive controls. In the original study, one month after one 4CMenB dose, 93% of subjects had seroprotective hSBA titers (≥4) against indicator serogroup B strains for individual vaccine antigens (fHbp, NadA and NZOMV), increasing to ~100% after two or three doses. After 18−24 mo, 62−73% of subjects given one dose had titers ≥4 against the three antigens, significantly lower rates than after two (77−94%) or three (86−97%) doses. Only proportions with titers ≥ 4 against NZOMV were significantly different between the two (77%) and three (90%, p < 0.0001) dose groups. These results confirm that two doses of 4CMenB, administered 1 to 6 mo apart, provide good levels of bactericidal activity against serogroup B meningococci, which were sustained at least 18−24 mo in over 64% of adolescents for all three tested vaccine-related antigens.

Copper is essential for cell metabolism in animals and plants and thus for life. Along centuries, copper has been identified as a metal containing antimicrobial properties. In recent years, laboratory assays and clinical studies have revealed that surfaces of metallic copper or its alloys, containing at least 70% copper, eliminate in a few hours several pathogenic organisms including bacterial strains associated with nosocomial infections, influenza virus, HIV, and fungi such as Candida albicans. In March 2008, the American Environmental Protection Agency (EPA), supported by scientific evidence gathered to date, registered copper as the first and only metal with antimicrobial properties. We herein review certain mechanisms proposed for the antibacterial, antiviral and antifungal activity of copper. We also discuss in vitro and clinical efficacy studies developed world wide and in Chile, focusing on bactericidal activity of copper surface areas in comparison to materials typically used in hospital environments such as stainless steel and polymers. Scientific evidence gathered to date, consistently shows that the use of copper surface areas in high contact critical points in hospitals, significantly reduces environmental bacterial load. This is associated with a decreased risk of pathogen transmission to patients and represents therefore an interesting complement to infection control programs.

Shigella sonnei gastroenteritis improves clinically and microbiologically with antibacterial treatment; however choosing a useful drug is a universal challenge because of in vitro susceptibility of S. sonnei frequently evolves to be resistant.To evaluate in vitro susceptibility of S. sonnei strains isolated from patients attending at the Chilean Región Metropolitana and to know the evolution that resistant patterns of S. sonnei have experienced.In this study, the antimicrobial susceptibility profile of 277 isolates of Shigella sonnei was compared. The analyzed periods of time were: period I (1995-1997) 85 strains; period II (2004-2006) 92 strains and period III (2008-2009) 100 strains, in Santiago, Chile. The method performed to analyze susceptibility patterns was the disc diffusion (Kirby-Bauer).The strains showed rates of resistance to ampicillin: period I, 85.8%; period II, 53.3%; period III, 100%, trimethoprim/sulfamethoxazole: period I, 50.5%; period, II 46.7%; period III, 100%, chloramphenicol: period I, 36.4%; period II, 12%; period III, 100% and tetracycline: period I, 38.8%; period II, 30.4%; period III, 100%. 98.9% of the strains showed susceptibility to quinolones. Significant differences were observed in patterns of antimicrobial resistance for both individuals and for multidrug resistance (≥ 3 antimicrobials) in the three periods (p0.001, χ2 test). Of all resistant strains, 17% were resistant to 1 or 2 antibiotics, while 65.7% showed a pattern of multidrug resistance; 100% of the period III strains presented multidrug resistance.These results showed the temporal resistance dynamics of S. sonnei circulating strains in the Chilean Región Metropolitana. Due to the endemic behavior of shigellosis in Chile, it is urgent to maintain permanent surveillance of antimicrobial resistance profiles to improve both prevention and treatment of shigellosis.

Copper has a bactericidal activity against a series of bacterial strains.To measure resistance to bacterial adherence of copper (Cu) and stainless steel (SS) metal coupons.Bacterial strains causing nosocomial infections in Chile were analyzed. Bacterial adherence was studied using a previously described method based on a system of metal coupons that are immersed in culture media containing the bacteria of interest at room temperature.Adherence to Cu and SS coupons was different for Methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae and Acinetobacter baumannii strains. For these strains, no adherence to Cu coupons occurred during the 48 h observation period compared to a rapidly increasing adherence to SS coupons, with a final colony count of 1.00 E + 07 cfu/mL. For two different Pseudomonas aeruginosa clinical strains, inhibition of adherence was not observed on Cu coupons, and colony counts were similar for Cu and SS using the standard inoculum (2-3 x lO7 cfu).A partial decrease in adherence was observed for Cu but not for SS coupons, when a lower inoculum was used.Copper surfaces represent an interesting option to reduce bacterial contamination in the hospital environment due to its resistance to bacterial adhesión of most of the common nosocomial bacterial strains.

Objective: 1) Evaluate the antimicrobial properties of copper in hearing aid molds against the most prevalent pathogens of otitis externa in an in vitro system. 2) Determine the most suitable mold material to allow adequate diffusion of copper ions to perform its antimicrobial action.Method: Experimental study conducted from January to December 2010, consisting of an in vitro system with hearing-aid molds made from different materials with and without copper in them, which were inoculated with external otitis pathogens at different concentrations (S aureus, P aeruginosa, C albicans, and A niger), then determine percentage of bacterial adhesion to materials.Results: There was a significant reduction in the percentage of microbial adherence to different mold materials with copper in them, in relation to those without copper, at different levels of microbial concentration for S aureus, P aeruginosa, C albicans, and A niger, while the percentages of adherence reduction fluctuated between 27% and 100% in those...

Effective glycoconjugate vaccines against Neisseria meningitidis serogroups A, C, W-135, and Y have been developed, but serogroup B remains a major cause of severe invasive disease in infants and adolescents worldwide. We assessed immunogenicity and tolerability of a four-component vaccine (4CMenB) in adolescents.We did a randomised, observer-blind, placebo-controlled, study at 12 sites in Santiago and Valparaíso, Chile. Adolescents aged 11-17 years received one, two, or three doses of 4CMenB at 1 month, 2 month, or 6 month intervals. Immunogenicity was assessed as serum bactericidal activity using human complement (hSBA) against three reference strains for individual vaccine antigens, and assessed by ELISA against the fourth strain. Local and systemic reactions were recorded 7 days after each vaccination, and adverse events were monitored throughout the study. Participants were initially randomised to five groups (3:3:3:3:1) during the primary phase to receive either one dose, two doses 1 or 2 months apart, or three doses of 4CMenB, or three doses of placebo, with an additional three groups generated for the booster phase. All subjects received at least one dose of 4CMenB. Geometric mean titres, proportions of participants with serum bactericidal antibody titres of 4 or more, and Clopper-Pearson 95% CIs were calculated. The study is registered with ClinicalTrials.gov, number NCT00661713.Overall, 1631 adolescents (mean age 13·8 [SD 1·9] years) received at least one dose of 4CMenB. After two or three doses, 99-100% of recipients had hSBA titres of 4 or more against test strains, compared with 92-97% after one dose (p0·0145) and 29-50% after placebo. At 6 months 91-100% of participants still had titres of 4 or more for each strain after two or three doses, but only 73-76% after one dose; seroresponse rates reached 99-100% for each strain after second or third doses at 6 months. Local and systemic reaction rates were similar after each 4CMenB injection and did not increase with subsequent doses, but remained higher than placebo. No vaccine-related serious adverse events were reported and no significant safety signals were identified.On the basis of immunogenicity responses this study provides evidence for an adolescent 4CMenB vaccine schedule of two doses, 1-6 months apart, to provide protection against meningococcal B infection. The extent of this protection against meningococcus B variants circulating worldwide will be determined by national surveys.Novartis Vaccines and Diagnostics.

In Latin America, acute gastroenteritis remains to be an important cause of morbidity in adults and a major cause of morbidity and mortality in children. A child under 5 years of age belonging to a low income segment of the Latin American population will develop 5 to 10 bouts of diarrhea every year. The bacterial and viral enteropathogens associated with acute diarrhea are reviewed in this article. Updated information on epidemiologic, clinical, and pathogenic aspects for the relevant enteropathogens is discussed with special emphasis on regional data when available. The current diarrheogenic E. coli classification is particularly discussed. A diagnostic approach to acute gastroenteritis for both the clinical and research laboratories in Latin America as well as guidelines for treatment are proposed.

Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea. Three adhesins (Tia, TibA, EtpA), an iron acquisition system (Irp1, Irp2, and FyuA), a GTPase (LeoA), and an autotransporter (EatA) are ETEC virulence-related proteins that, in contrast to the classical virulence factors (enterotoxins and fimbrial colonization factors) have not heretofore been targets in characterizing isolates from epidemiological studies. Here, we determined the occurrence of these nonclassical virulence genes in 103 ETEC isolates from Chilean children with diarrhea and described their association with O serogroups and classical virulence determinants. Because tia , leoA , irp2 , and fyuA are harbored by pathogenicity islands inserted into the selC and asnT tRNA genes (tDNAs), we analyzed the regions flanking these loci. Ten additional tDNAs were also screened to identify hot spots for genetic insertions. Associations between the most frequent serogroups and classical colonization factor (CF)-toxin profiles included O6/LT-STh/CS1-CS3-CS21 (i.e., O6 serogroup, heat-labile [LT] and human heat-stable [STh] enterotoxins, and CFs CS1, -3 and -21), O6/LT-STh/CS2-CS3-CS21, and O104-O127/STh/CFAI-CS21. The eatA and etpA genes were detected in more than 70% of the collection, including diverse serogroups and virulence profiles. Sixteen percent of the ETEC strains were negative for classical and nonclassical adhesins, suggesting the presence of unknown determinants of adhesion. The leuX , thrW , and asnT tDNAs were disrupted in more than 65% of strains, suggesting they are hot spots for the insertion of mobile elements. Sequences similar to integrase genes were identified next to the thrW , asnT , pheV , and selC tDNAs. We propose that the eatA and etpA genes should be included in characterizations of ETEC isolates in future epidemiological studies to determine their prevalence in other geographical regions. Sequencing of tDNA-associated genetic insertions might identify new ETEC virulence determinants.

The incidence of diarrhea due to six categories of diarrheogenic Escherichia coli was determined in two pediatric cohorts in a low socioeconomic level community in Santiago, Chile, with access to chlorinated water. An age cross-sectional cohort of 340 children aged birth to 47 months was assembled. A newborn cohort was assembled by enrolling 10-12 newborns monthly for 12 months. Episodes of diarrhea were detected by twice weekly household visits. E. coli from stool cultures of cases and matched controls were hybridized with DNA probes specific for enterotoxigenic, enteroinvasive, enteropathogenic, enterohemorrhagic, enteroaggregative, and diffuse adherence E. coli. Overall, the incidence of diarrhea was low (2.1 episodes/infant/year). Nevertheless, a putative E. coli enteropathogen was found in a large proportion of diarrheal episodes, particularly during the summer. In both cohorts, enterotoxigenic E. coli were important pathogens. Enteropathogenic E. coli were incriminated during the first year of life in the newborn cohort, where they were found significantly more often in cases (p = 0.021) than in controls; beyond this age, isolation rates were similar. In contrast, the relative risk of isolation of diffuse adherence E. coli increased with age in the age cross-sectional cohort, where, overall, the difference in rate of isolation between cases and controls was significant (p = 0.0024). Enteroinvasive and enterohemorrhagic E. coli were isolated infrequently. Enteroaggregative E. coli were encountered equally in cases and controls. Facile transmission of E. coli enteropathogens is occurring in this community despite the availability of potable water.Researchers conducted an age cross sectional cohort analysis of 340 0-47 month old children and newborn cohort analysis of 144 newborns to determine the diarrheogenic Escherichia coli incidence in Santa Julia, a low socioeconomic community in Santiago, Chile. Children in the age cross sectional cohort had age, sex, and sector matched controls. The newborns had sex matched controls. A public health nurse or nurse auxiliary visited the household of each subject 2 times a week to detect diarrhea episodes. Between December 1986 and February 1990, the age cross sectional cohort had 1178 episodes of diarrhea and the newborn cohort had 674 episodes. The overall diarrhea incidence was only 2.1 episodes/child/year. An E. coli enteropathogen was isolated in many of these episodes, especially during the summer (e.g. enterotoxigenic E. coli [ETEC], 2.2 cases/month in summer vs. 0.4 cases/month in winter; p = .00001). Diffuse adherence E. coli (DAEC) and enteropathogenic E. coli (EPEC) infections also peaked in the summer. ETEC contributed greatly to diarrheal episodes in both cohorts. Among newborns, EPEC was isolated significantly more often in cases than controls during the 1st 12 months of life (6.7% vs. 2.5%; p = .021). After 1 year, however, E. coli isolation rates were essentially the same. On the other hand, in the age cross sectional cohort, the relative risk of isolation of DAEC rose with age (e.g., 1.1 for 0.11 months, 1.4 for 36-47 months, and 2.1 for = or 48 months). In the same cohort, DAEC infections were much more common in cases than controls (16.6% vs. 11.9%; p = .0024). Enteroinvasive and enterohemorrhagic E. coli were the most rarely isolated E. coli types. No difference in the isolation rate of enteroaggregative E. coli existed between cases and controls. Since most households in Santa Julia have access to potable water (68%) and an indoor toilet (64%), food contamination were likely the vehicles of E. coli transmission because more than 50% of households do not have a refrigerator.

Shiga toxin-producing Escherichia coli (STEC) are emerging pathogens worldwide. Infections associated with STEC have a broad clinical spectrum from asymptomatic infections, acute diarrhea, dysenteric diarrhea and Hemolytic Uremic Syndrome. Some serotypes of STEC are highly virulent for humans due to the presence of two cytotoxins (Stx1, Stx2) and a pathogenicity island called Locus of Enterocyte Effacement (LEE), which is responsible for the adherence to intestinal epithelium, mainly through the intimin protein encoded by eae gene. Other factors have been implicated in virulence, e.g., the products of the efa1, iha, hylA, lpf and saa genes, which are encoded in the genomes of O157 and non-O157. In Chile, STEC Non-O157 serogroups are the most important cause of STEC infections. It has been found that the presence of these specific genes is more relevant than is that of the serogroup. In Chile, a high rate of STEC isolations in swine and bovines as asymptomatic carriers has been reported. Therefore the Chilean Ministry of Health has incorporated STEC as an agent under surveillance. Recently, samples from swine and bovines at slaughter were analyzed and, interestingly, only the bovine carrying STEC exhibited the virulence genes found in human isolates. Several strategies have been proposed to prevent STEC colonization in the animal host, where findings following vaccination with proteins from the LEE locus are encouraging. Thus,, DNA vaccines have been used as a novel strategy, and the immunized animals have shown a strong lymphocyte proliferation against bacterial antigens.

In the 21st century, diarrhea is still a leading cause of illness and death especially in children in Latin American countries. ETEC, EHEC, EPEC, and EAEC remain as the major categories of pathogenic E. coli associated with diarrheal disease; however, it is evident that a shift in the serotypes responsible for human disease is occurring in this region. Recent reports implicated atypical EPEC as an important emerging category of E. coli and the association of EHEC O157:H7 as a cause of hemolytic uremic syndrome in Latin America is becoming evident. Significant improvements are required in the area of early diagnosis to increase the likelihood of an effective treatment. In this region, very few studies have addressed the emergence of antimicrobial resistance and high asymptomatic carriage rates for diarrheagenic E. coli (DEC), as well as non-human reservoirs and vehicles of transmission, are largely unknown. It is evident that broadening the epidemiological surveys to include emerging and re-emerging categories of DECs while increasing the capabilities of detection and novel treatment is a priority for the future of the E. coli research in Latin America.

Shiga toxin-producing Escherichia coli (STEC) can produce a wide spectrum of human diseases, being an important cause of both outbreaks and sporadic cases of bloody and non-bloody diarrhea, hemorrhagic colitis, the diarrhea-associated form of hemolytic uremic syndrome (HUS) worldwide. HUS is a major cause of acute renal failure in children. Albeit O157:H7 is by far the most important serotype in human infections, several different O:H serotypes of E. coli can harbor Shiga toxin (stx) genes, and actually some non-O157 strains cause illnesses that are comparable in severity to O157-induced diseases, posing a substantial concern to public health. Infections due to STEC have a proven zoonotic character as these bacteria are largely distributed among both domestic and wildlife animal species. STEC infections are transmitted to humans through contaminated food, water, and contact with infected animals or people. The cascade leading from gastrointestinal infection to renal impairment is complex, being the production of Stx the major pathogenicity determinant of STEC. However, a mosaic of different virulence traits comprising several adhesins and other toxins that may play a role in pathogenesis has also been described. There is no specific treatment to reduce the progression of HUS. Research is still necessary to improve our knowledge on the mechanisms of Stx infections and the pathophysiology of cell injury in HUS to lead to better therapeutic strategies to prevent the acute mortality and the long-term morbidity of HUS.

Rotavirus and more recently noroviruses are recognized as main causes of moderate to severe acute diarrhea episodes (ADE) in childrenor =5 years of age. Comparing epidemiologic and clinical features of norovirus to rotavirus ADE will aid in the decision-making process required to develop norovirus vaccines.Surveillance for ADE occurring in childrenor =5 years of age was implemented in the emergency department (ED) and ward of a large hospital in Santiago and Valparaiso, and in 4 outpatient clinics in Santiago. A stool sample was obtained within 48 hours of consultation for rotavirus detection by enzyme-linked immunosorbent assay and noroviruses by enzyme-linked immunosorbent assay or reverse transcription polymerase chain reaction. For ED and hospital rotavirus and norovirus ADE parents were instructed to monitor clinical findings associated with severity until the end of the episode. The 20-point Vesikari score was used to determine disease severity.Between July 2006 and October 2008 rotavirus and noroviruses were detected in 331 (26%) and 224 (18%) of 1913 ADE evaluated. The proportion of rotavirus-positive samples in hospital ward, ED, and outpatient clinic was 40%, 26% to 30%, and 13% compared with 18%, 17% to 19%, and 14% for noroviruses. Mean age and 25%-75% interquartile interval of children with rotavirus and norovirus ADE were remarkably similar, 15.6 months (9-20), and 15.5 months (9-19), respectively. Rotavirus cases displayed an autumn-winter peak followed 2 to 3 months later by the norovirus peak. The mean (interquartile) for the Vesikari score was 12.9 (11-15) and 11.9 (9-14.5) for rotavirus (N = 331) and norovirus (N = 224) ADE, respectively, P = 0.003. Compared with norovirus, rotavirus ADE were more common in the 11 to 16 severity score interval (P = 0.006), had a higher maximum stool output in a given day (P = 0.01) and more frequent fever (P0.0001). Duration of diarrhea, presence, duration and intensity of vomiting, and intensity of fever did not differ between viruses. Mixed rotavirus and norovirus infections were uncommon (1%) and not clinically more severe. Clinical severity of ADE in young infants was similar for rotavirus and lower (P = 0.03) for noroviruses compared with older children.Noroviruses are a significant cause of moderate to severe endemic ADE in Chilean children. Although significantly less severe than rotavirus as a group, most norovirus episodes were moderate to severe clinically. An effective norovirus vaccine would be of significant additional benefit to the current rotavirus vaccine in decreasing disease burden associated with ADE.

A clinicoepidemiological study was undertaken to determine if enterohemorrhagic Escherichia coli (EHEC) was associated with hemolytic-uremic syndrome (HUS) in children in Santiago, Valdivia, and Temuco, Chile. Prospective surveillance detected 20 hospitalized cases of HUS in children less than 4 years of age in these cities from March 1988 to March 1989. Each HUS patient was matched (by sex and age) with two control children (hospitalized elective-surgery patients). To detect EHEC, DNA from stool culture isolates of E. coli was detected by hybridization with biotin-labelled DNA probes specific for the EHEC virulence plasmid, Shiga-like toxin I (SLT-I) or SLT-II. Stool cultures from 6 of 20 cases (30%) and from 2 of 38 controls (5.3%) yielded EHEC (P = 0.0158). EHEC isolates from all HUS cases hybridized with the EHEC plasmid probe and with probes for SLT-I or -II (or both). The serogroups of the isolates included O157, O26, and O111. EHEC causes HUS in Chile, and the biotinylated gene probes are practical diagnostic tools for epidemiologic studies.

Current methods to detect the colonization factor antigens (CFAs) associated with enterotoxigenic Escherichia coli (ETEC) strains are cumbersome, with some methods requiring antibodies that are not readily available. To achieve a gene-based method, we designed 2 multiplex polymerase chain reaction reactions to detect genes encoding the most common ETEC fimbrial colonization factors, including CFA/I and coli surface (CS) antigens CS1, CS2, CS3, CS4, CS5, and CS6. Analysis of 183 clinical ETEC strains shows that the most prevalent colonization factors were CFA/I only, CS1 and CS3, CS2 and CS3, and CS6 only. Interestingly, we identified 3 clinical isolates expressing CS1 only without its regulator rns. The method described here proved to be rapid and robust and correlates well with phenotypic expression of the CFAs, becoming a novel molecular diagnostic and research tool for future epidemiologic studies.

Clinical and epidemiological aspects of shigatoxin producing E. coli (STEC) infections and hemolytic uremic syndrome (HUS) are reviewed. Surveillance results from 14 sentinel centers during 2000-2002 showed a mean incidence rate of 3.4 HUS cases per 100,000 children, with the highest incidence in the 6 to 28 month age group. Disease is endemic with summer peaks. Between 1988 and 2002 we obtained the clinical characteristics of a group of 119 HUS children with the following results: mean age 16 months, bloody diarrhea 57.8%, no previous diarrhea 9%, 60% received antibiotics, 72% had oligoanuria, 53% required dialysis, 15% had seizures and 31% had dizziness; mortality was 3%. Four foodborne outbreaks have been detected in Santiago, two outbreaks occurred in household settings, one in a Day Care Center and one in a Neonatal Unit. Recommendations for diagnosis, treatment and prevention of STEC infections, including potential vaccines are discussed.

Se revisan y actualizan aspectos clínicos y epidemiológicos de las infecciones por Escherichia coli productora de shigatoxina (STEC), y el síndrome hemolítico urémico (SHU). Se incluyen resultados de una vigilancia de SHU en 14 centros centinelas (2000-2002), que mostró una incidencia promedio de 3,4 casos por 100.000 niños, 78%) en el grupo de 6 a 48 meses. Esta vigilancia reflejó una situación endémica, con aumento en verano. Se analiza la observación clínica protocolizada de 119 pacientes con SHU hospitalizados en la Región Metropolitana (RM) (1988 y 2002). Edad promedio: 16 meses. El 578%> tenía diarrea con sangre, 9%> no tenía diarrea previa, 60%> recibió antibacterianos, 72%> presentó oligoanuria y 53%> necesitó diálisis. El 31%o tuvo compromiso de conciencia y 15%o presentó convulsiones. Letalidad 3%. Se analizan brotes de STEC asociados a alimentos ocurridos en la RM en el hogar (2), un jardín infantil (1) y en un servicio de neonatología (1). Finalmente, se entregar recomendaciones para el manejo clínico y prevención, se revisan los criterios diagnósticos, nuevas estrategias terapéuticas y progresos en el desarrollo de vacunas.

Acute bacterial meningitis (ABM) is a serious disease that needs rapid diagnosis for an accurate treatment. The most important etiological agents are: Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b. Overall pathogen detection rate in patients with ABM in Chile is 83%.To evaluate a Polymerase Chain Reaction (PCR) protocol for simultaneous detection of several pathogens in patients with ABM.We designed and evaluated a multiplex PCR protocol for simultaneous specific genes identifications of S pneumoniae ( inverted exclamation markytA and ply genes), N meningitidis (ctrA, crgA) and H influenzae (bexA) in cerebrospinal fluid (CSF) samples from pediatric patients with suspected diagnosis of ABM. Sensitivity, specificity and minimum detection levels of DNA were determined. Amplifications ofrDNA 16S gene was done to confirm extraction of bacterial DNA.Ninety nine CSF samples were studied, 90 from children with fever and negative CSF culture, and 9 from ABM and positive culture patients. The PCR protocol had a sensitivity of 89%, specificity of 100%, positive predictive value 100% and negative predictive value 99%.We observed a high concordance (89%) between bacteriological cultures and the PCR protocol results. This diagnostic tool could increase identification of agents in specific settings such as patients previously treated with antibiotics.

Background: Acute bacterial meningitis (ABM) is a serious disease that needs rapid diagnosis for an accurate treatment. The most important etiological agents are: Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b. Overall pathogen detection rate in patients with ABM in Chile is 83%. Aim: To evaluate a Polymerase Chain Reaction (PCR) protocol for simultaneous detection of several pathogens in patients with ABM. Material and methods: We designed and evaluated a multiplex PCR protocol for simultaneous specific genes identifications of S pneumoniae (¡ytA and ply genes), N meningitidis (ctrA, crgA) and H influenzae (bexA) in cerebrospinal fluid (CSF) samples from pediatric patients with suspected diagnosis of ABM. Sensitivity, specificity and minimum detection levels of DNA were determined. Amplifications ofrDNA 16S gene was done to confirm extraction of bacterial DNA. Results: Ninety nine CSF samples were studied, 90 from children with fever and negative CSF culture, and 9 from ABM and positive culture patients. The PCR protocol had a sensitivity of 89%, specificity of 100%, positive predictive value 100% and negative predictive value 99%. Conclusions: We observed a high concordance (89%) between bacteriological cultures and the PCR protocol results. This diagnostic tool could increase identification of agents in specific settings such as patients previously treated with antibiotics

Shigella spp is a frequent cause of diarrhea in children. Antimicrobials decrease the duration of diarrhea and pathogen excretion. However, the increasing resistance limits their therapeutic value.To study Shigella serotype distribution in the Metropolitan Region in Chile, and its relationship with severity of disease, antimicrobial resistance pattern and clonality.During summer 2004-2005, stool samples from children with diarrhea were collected in Cary Blair transpon medium and cultured. Shigella isolates were serotyped using monoclonal and polyclonal commercial antibodies. In vitro activity of ampicillin, amoxicillin/clavulanic acid, chloramphenicol, cotrimoxazol, nalidixic acid, ciprofloxacin, ceftriaxone and azythromycin was determined by minimal inhibitory concentration (MIC). Clonality was studied by pulsed-field gel electrophoresis (PFGE) using Xbal as restriction enzyme.One hundred thirty nine Shigella strains were isolated (77 S sonnei and 62 S flexneri). S sonnei and S flexneri 2a serotypes were responsible for 95% of episodes. Children aged 2-4 years, showed a greater incidence of Shigella infections and 77% of episodes were treated on an ambulatory basis. High resistance levels were observed for ampicillin, cotrimoxazole, amoxicillin-clavulanic acid and chloramphenicol (67%, 60%, 56% and 45%, respectively). We found 11 resistance patterns and 61,2% of strains were multiresistant. There were multiple clones without a strict relationship with resistance patterns.Shigella infections in Metropolitan Region in Chile are associated to a restricted number of serotypes, representing a clonal expansion associated to different antimicrobial resistant patterns.

Background: Shigella spp is a frequent cause of diarrhea in children. Antimicrobials decrease the duration of diarrhea and pathogen excretion. However, the increasing resistance limits their therapeutic value. Aim: To study Shigella serotype distribution in the Metropolitan Region in Chile, and its relationship with severity of disease, antimicrobial resistance pattern and clonality. Material and methods: During summer 2004-2005, stool samples from children with diarrhea were collected in Cary Blair transpon medium and cultured. Shigella isolates were serotyped using monoclonal and polyclonal commercial antibodies. In vitro activity of ampicillin, amoxicillin/clavulanic acid, chloramphenicol, cotrimoxazol, nalidixic acid, ciprofloxacin, ceftriaxone and azythromycin was determined by minimal inhibitory concentration (MIC). Clonality was studied by pulsed-field gel electrophoresis (PFGE) using Xbal as restriction enzyme. Results: One hundred thirty nine Shigella strains were isolated (77 S sonnei and 62 S flexneri). S sonnei and S flexneri 2a serotypes were responsible for 95% of episodes. Children aged 2-4 years, showed a greater incidence of Shigella infections and 77% of episodes were treated on an ambulatory basis. High resistance levels were observed for ampicillin, cotrimoxazole, amoxicillin-clavulanic acid and chloramphenicol (67%, 60%, 56% and 45%, respectively). We found 11 resistance patterns and 61,2% of strains were multiresistant. There were multiple clones without a strict relationship with resistance patterns. Conclusions: Shigella infections in Metropolitan Region in Chile are associated to a restricted number of serotypes, representing a clonal expansion associated to different antimicrobial resistant patterns

The frequency of astrovirus infection in 456 Chilean children with diarrhea was determined by enzyme-linked immunosorbent assay, reverse transcriptase PCR, and cell culture. Astrovirus was detected in 16.5% of rotavirus-negative and 7% of rotavirus-positive samples obtained from emergency rooms or hospitals and in 11% of samples from day care centers. HAst-1 was the predominant serotype identified.

SUMMARYThe distribution of three putative adhesin genes in 123 Shiga toxin-producing (STEC) strains was determined by PCR. The STEC strains were isolated from human patients (n=90) and food (n=33) and were characterized by serogroup, virulence markers (eae,stx1,stx2) and adherence factors (efa1,lpfAO157,saa) genes. Serogroups O157 (64·4%) and O26 (28·8%) were the most frequent among human strains and the majority (60·6%) of food strains were serologically non-typable. The adhesin genesefa1 (90%) andlpfAO157(73·3%) were the most common in humans strains andsaa(45·5%) in food strains. The presence of these genes in addition toeaein STEC from different sources may suggest a relevant role in their pathogenesis.

Capsid and polymerase (RdRp) genes of 13 norovirus outbreak strains from Chile were compared. The genes sequences were discordant for five strains, and recombination was confirmed for two of them by amplification of a 1,360-bp gene segment containing a fragment of both genes. These strains belonged to a novel genogroup by RdRp sequence and to genogroup GII/3 by capsid sequence. Determining the clinical and epidemiological impact of human calicivirus recombination will require future studies.

Cefpodoxime is a new antimicrobial in the Chilean market, recommended for treatment of respiratory and urinary tract infections.To study the susceptibility of common pathogens isolated from Chilean patients to cefpodoxime and other antimicrobials.The in vitro activity of cefpodoxime, expressed as Minimal Inhibitory Concentration, was studied in 331 S pneumoniae, H influenzae, M catarrhalis, E coli, S aureus and S pyogenes strains, isolated between 2000 and 2004 from respiratory, urinary and soft tissue infections, respectively.Eleven percent of S pneumoniae isolates were resistant to penicillin, 11% were resistant to cefuroxime and 10% to cefpodoxime. All H influenzae isolates were susceptible to cefpodoxime. No H influenzae isolates were resistant to second or third generation cephalosporines. Four percent of H influenzae isolates were resistant to ampicillin by ss-lactamase production. In contrast 81% of M catarrhalis strains were resistant to ampicillin. Six percent of E coli isolates were resistant to cefpodoxime, 9% to cefuroxime, 11% to cefadroxile and 50% to ampicillin or trimethoprim/sulphamethoxazole. Cefpodoxime was the most active antimicrobial against S pyogenes.Cefpodoxime, recently introduced in Chile, is a good alternative for the treatment of common respiratory and urinary tract infections.

Background: Cefpodoxime is a new antimicrobial in the Chilean market, recommended for treatment of respiratory and urinary tract infections. Aim: To study the susceptibility of common pathogens isolated from Chilean patients to cefpodoxime and other antimicrobials. Material and methods: The in vitro activity of cefpodoxime, expressed as Minimal Inhibitory Concentration, was studied in 331 S pneumoniae, H influenzae, M catarrhalis, E coli, S aureus and S pyogenes strains, isolated between 2000 and 2004 from respiratory, urinary and soft tissue infections, respectively. Results: Eleven percent of S pneumoniae isolates were resistant to penicillin, 11% were resistant to cefuroxime and 10% to cefpodoxime. All H influenzae isolates were susceptible to cefpodoxime. No H influenzae isolates were resistant to second or third generation cephalosporines. Four percent of H influenzae isolates were resistant to ampicillin by ß-lactamase production. In contrast 81% of M catarrhalis strains were resistant to ampicillin. Six percent of E coli isolates were resistant to cefpodoxime, 9% to cefuroxime, 11% to cefadroxile and 50% to ampicillin or trimethoprim/sulphamethoxazole. Cefpodoxime was the most active antimicrobial against S pyogenes. Conclusions: Cefpodoxime, recently introduced in Chile, is a good alternative for the treatment of common respiratory and urinary tract infections

Variations in antibiotic resistance patterns were studied among 178 Shigella strains isolated from 1997 to 2001 in children less than five years of age with acute diarrhea from Colina, a semi-rural community in Santiago, Chile. The minimal inhibitory concentration of several commonly used antibiotics was determined by the agar dilution method. Shigella strains showed high rates of resistance to ampicillin (82%), cotrimoxazole (65%), tetracycline (53%), and chloramphenicol (49%). Furthermore, 51% of the strains showed resistance patterns to multiple antibiotics. Only 9% of the strains were resistant to amoxicillin-clavulanic acid and no resistance was observed to ciprofloxacin, nalidixic acid, or cefotaxime. Continuous monitoring of resistance patterns in Shigella is essential for establishing and updating guidelines for antibiotic treatment in shigellosis.

Telithromycin is a new ketolide antimicrobial, that can be useful for the treatment of respiratory infections.To compare in vitro activity of telithromycin against respiratory pathogens, isolated in outpatient clinics.Two hundred eighty strains isolated from patients with respiratory infections, were studied. The strains studied were S pneumoniae, penicillin sensitive (SPNS:57); intermediate (SPNI:35), resistant (SPNR:25); S pyogenes (SP:57); H influenzae (HIN 51); M catarrhalis (MC:25) and S aureus meticillin sensitive (SAUS:30). Minimal inhibitory concentration (MIC) by broth microdilution was studied for telitrhomycin and levofloxacin in all strains. Other antimicrobials studied, but not in all strains were erythromycin, clindamycin, trimetoprim sulphamethoxazole, oxacillin, amoxicillin-clavulanic acid and cefuroxime.All strains were sensible to telithromycin at a concentration -4 microg/ml. MIC 90 and its range for SPNS was 0.03 microg/ml (-0.004-0.12), for SPNI was 0.03 microg/ml (-0.004-025), for SPNR was 0.06 microg/ml (-0.004-0.25), for HIN was 2 microg/ml (0.12-4), for SP was 0.5 microg/ml (-0.004-2), for MC was 0.5 microg/ml (0.06-2) and for SAU was 0.25 microg/ml (0.06-0.25).All studied pathogens were sensible to telithromycin in vitro. This antimicrobial is an alternative for the treatment of community acquired respiratory infections.

More than one billion diarrhea episodes occur every year among children younger than 5 years of age in socioeconomically developing countries causing 2 to 2.5 million deaths. More than twenty viral, bacterial, and parasitic enteropathogens are currently associated with acute diarrhea. Rotavirus and diarrheagenic Escherichia coli are the most common pathogens responsible for acute diarrhea episodes in children; Shigella spp., Salmonella spp, Campylobacter jejuni/coli, Vibrio cholerae, Aeromonas spp, and Plesiomonas spp. occur more commonly in poorer areas and infections caused by protozoa and helminthes occur mainly in areas where environmental sanitation is significantly deteriorated. Initial clinical assessment of a child with diarrhea should focus on obtaining an accurate evaluation of hydration and nutritional status. Assessment of stool characteristics (e.g., liquid non-bloody stools vs. dysenteric or bloody stools) is a key feature in determining potential pathogens causing an acute diarrhea episode. Diagnostic guidelines are discussed in the article. The major therapeutic intervention for all individuals with diarrhea consists of fluid and electrolyte therapy. When antimicrobial therapy is appropriate, selection of a specific agent should be made based upon susceptibility patterns of the pathogen or information on local susceptibility patterns. Current guidelines for administering appropriate antimicrobial treatment are provided in the article. Preventive measures include careful personal hygiene, especially promotion of hand washing. Immunizations currently or soon to be available for Salmonella serotype Typhi, cholera prevention, and rotavirus are discussed.

Background: Telithromycin is a new ketolide antimicrobial, that can be useful for the treatment of respiratory infections. Aim: To compare in vitro activity of telithromycin against respiratory pathogens, isolated in outpatient clinics. Material and methods: Two hundred eighty strains isolated from patients with respiratory infections, were studied. The strains studied were S pneumoniae, penicillin sensitive (SPNS:57); intermediate (SPNI:35), resistant (SPNR:25); S pyogenes (SP:57); H influenzae (HIN 51); M catarrhalis (MC:25) and S aureus meticillin sensitive (SAUS:30). Minimal inhibitory concentration (MIC) by broth microdilution was studied for telitrhomycin and levofloxacin in all strains. Other antimicrobials studied, but not in all strains were erythromycin, clindamycin, trimetoprim sulphamethoxazole, oxacillin, amoxicillin-clavulanic acid and cefuroxime. Results: All strains were sensible to telithromycin at a concentration ­4 µg/ml. MIC 90 and its range for SPNS was 0.03 µg/ml (­0.004-0.12), for SPNI was 0.03 µg/ml (­0.004-025), for SPNR was 0.06 µg/ml (­0.004-0.25), for HIN was 2 µg/ml (0.12-4), for SP was 0.5 µg/ml (­0.004-2), for MC was 0.5 µg/ml (0.06-2) and for SAU was 0.25 µg/ml (0.06-0.25). Conclusions: All studied pathogens were sensible to telithromycin in vitro. This antimicrobial is an alternative for the treatment of community acquired respiratory infections

Background: Shiga toxin-producing E coli (STEC) are zoonotic pathogens associated to sporadic episodes of bloody diarrhea, foodborne outbreaks, and Hemolytic Uremic Syndrome (HUS), with worldwide public health impact. Antibiotic use in STEC infections is controversial because of the potential to increase production and secretion of Shiga toxins. Aim: To study the in vitro antimicrobial susceptibility profile of STEC. Material and methods: The in vitro susceptibility profile against 10 antimicrobials of STEC strains isolated from 29 meat products, 20 patients with diarrhea and 9 HUS patients was studied. Minimal Inhibitory Concentrations (µg/ml) by agar dilution method for ampicillin, cloramphenicol, ciprofloxacin, amikacin, gentamycin, cotrimoxazol, ceftriaxone, tetracycline, fosfomycin and azithromycin were measured according to NCCLS recommendations. Results: Strains from patients with diarrhea or HUS were all susceptible to the 10 antimicrobials and only 13.7% had intermediate resistance to cloramphenicol. Strains from meat products had a similar susceptibility profile, with only 3.5% resistance to tetracycline, 3.5% intermediate resistance to cloramphenicol and 7% to fosfomycin. All 58 strains were considered resistant to azithromycin (MIC >32 ug/ml). Conclusions: Similarity of susceptibility profiles between STEC strains from human and food origin suggests a role of food chain in transmission to humans (Rev Med Chile 2004; 132: 1211-6). (Key Words: Escherichia coli O157; Hemolytic-uremic syndrome, Shiga toxin)