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Introduction: Extended-spectrum-β-lactamases (ESBL) are plasmid-encoded enzymes that confer resistance to multiple antimicrobials. ESBL-producing enterobacteria that cause bacteremia limit therapeutic options and increase mortality., Objective: To perform a clinical and molecular description of bacteremia caused by ESBL-producing enterobacteria., Method: We retrospectively studied the cases of bacteremia due to ESBL-producing Escherichia coli, Klebsiella pneumoniae and Proteus spp in adults admitted to a university hospital during the years 2004-2007. We reviewed the clinical records and antimicrobial susceptibility patterns. Molecular typing was performed by polymerase chain reaction and study of clonality by pulsed-field electrophoresis., Results: We found a prevalence of 9.8% ESBL in enterobacteria causing bacteremia. Decreased susceptibility to quinolones and aminoglycosides was observed, without resistance to carbapenems. The predominant ESBL types were CTX-M (96%), TEM (62%) and GES (28%). 79% of the strains presented more than one type of ESBL. Clinical analysis revealed high prevalence of risk factors, previous use of antimicrobials and of invasive devices. There was no significant clonality., Conclusion: The presence of ESBLs in bloodstream infections is a clinical problem that must be considered when choosing empiric therapy.

Introduction: Toxoplasmosis (T) is a major chronic parasitic infection in immunocompromised patients and pregnant women. It is important to discriminate between acute phase (AT) and chronic phase (CT). Diagnosis is serological in immunocompetent patients (concentration of IgG and IgM)., Objective: To evaluate the utility of an IgG avidity test (A-IgG) to identify the acute and chronic stage. Avidity is the strength of affinity between a specific immunoglobulin and the protein antigenic epitope of the infecting agent, an affinity that increases over time., Patients and Methods: We used a qualitative kit that measures the avidity of IgG, discriminating the two phases. In 35 patients with clinical diagnosis of AT and/or CT, IgG, IgM and IgG A (VIDAS®) were performed., Results: Patients with AT were positive for IgM and IgG, but presented weak avidity. In the 21 cases with CT, 52% (n: 11) were IgM positive and 100% (n: 21) had positive IgG with strong avidity., Discussion: The results confirm that the test of A-IgG may be useful in the diagnosis of AT, and has 100% concordance with reference test (qualitative IgM + quantitative IgG). The result is available within 24 hrs, and may be useful in diagnosis of AT in pregnant women.

Globalization of health care seems to be irreversible and beyond cultural differences and local realities; consequently, medical education needs to have a common set of core principles or standards that may be applied worldwide. The aim of participating in assessment processes is to guarantee that medical education takes place in a sufficiently rich environment to promote extensive academic purposes. The Medical School of the Pontificia Universidad Católica de Chile (PUC) participated in three assessment processes that included three stages: internal assessment, external assessment, and accreditation judgment. Two of these assessments were voluntarily carried out following the standards set by the Liaison Committee on Medical Education-LCME, and they took place in 1997 and 2007. The other assessment was based on standards set by the Chilean accrediting organism, the National Committee for Undergraduate Program Accreditation (Comité Nacional de Acreditación de Pregrado-CNAP) and took place in the year 2001. In all three experiences, internal assessment was the most enriching stage, stimulating refections among students and teachers in order to recognize areas of strengths and weaknesses. External assessment processes, especially those based on international standards, are very important for the institutional and program development of Medical Schools. The PUC Medical School on its whole learnt how to carry out an assessment process and was able to improve several weaknesses without pressure, moving from quality assurance to quality enhancement. The present paper analyzes the major challenges involved in an external assessment process.

The use of techniques for the detection of nucleic acids such as the polymerase chain reaction (PCR) has had a major impact on microbiological analysis, playing an important role in the clinical laboratory. Most of the techniques currently used are designed for specific detection of a particular microorganism. However, infectious agents can also be identified even if genus or species are unknown, using universal primers to amplify bacterial or fungal DNA and then identify the species by sequence (universal or wide spectrum PCR). This methodology is applied in cultures that are difficult to identify using phenotypic techniques, and more recently it is also being used directly in clinical samples, where the detection and identification of the infectious agent by traditional techniques is difficult or not possible.

The objective of this multicenter study was to determine tigecycline susceptibility rates, measured by agar diffusion, in nine hospitals in Santiago and to compare these rates with other antimicrobials. Each center studied 20 strains per month. All intermediate and fully resistant strains as well as 10% of susceptibile strains were also studied by the broth microdilution method. Overall, 2301 strains were studied displaying the following susceptibility rates for tigecycline: 100% for Streptococcus sp, Enterococcus sp, and E. coli respectively, 99.8% for Staphylococcus sp, 93% for Klebsiella and 80% for Acinetobacter baumarmii. For Proteus, Providencia and Morganella the susceptibility rates were 4%. For cefotaxime-resistant Klebsiella and imipenem-resistant A. baumarmii susceptibility rates were 95% and 80% respectively. The agar diffusion and broth dilution method were 100% concordant for tigecycline susceptible strains but only 27% for resistant or intermediate strains represented mostly by Acinetobacter baumannii. The majority of these strains (57/59) proved to be susceptible after retesting. The great majority (96,6%) of strains tested from nine Chilean hospitals proved to be susceptible to tigecycline with exception for Proteus, Providencia and Morganella (66% resistance). Using the agar diffusion method for measuring tigecycline susceptibility to A. baumannii may be misleading.

Introduction: The surveillance of febrile neutropenia (FN) episodes in every center allows adapt the antibiotic therapy guidelines to local epidemiology., Aim: To characterize clinical features and compare the FN etiology between hematological cancer (HC) and solid organ cancer (SOC) in our center., Patients and Methods: Surveillance study in adult patients with FN admitted to Hospital Clinico Universidad Católica, in Santiago, Chile, from January 2004 to August 2007., Results: 154 FN episodes corresponding to 87 patients were included. Mean age: 47 +/- 6 years-old; 71% had HC and 29% SOC. A clinical and/or microbiologically documented infection was recognized in 76%. Gastrointestinal 31.5%, upper respiratory 30.3% and lower respiratory 16.9% were the more frequent clinical focus. In 30.5% blood culture resulted positive: gram negative rods 51%, gram positive cocci 41% and yeasts 8%; being Escherichia coli 22%, S. coagulase negative (SCoN) 20% and Klebsiella pneumoniae 12% most frequent bacteria; 22.2% Enterobacteriaceae were ESBL producers and 55.6% 5CoN were methicillin resistant. In 18.3% of FN episodes the etiology was not established. Highest mortality was observed in episodes with microbiologically documented infection (14.5% vs 1.3%, p < 0.005). A clinical observed focus and positive blood cultures were more frequently obtamed among HC than SOC associated episodes: 37.3% vs 13.6%; (p < 0.01) and 67.2% vs 50%; (p = 0.045), respectively., Conclusions: The etiological profile of FN in our center and the necessity to continue the surveillance was described. Future studies are needed regarding risk factors of invasive infection that have worst prognosis.

Listeria monocytogenes is Gram-positive facultative intracellular pathogen often foodborne and found elsewhere. It is an uncommon cause of illness in the general population. However, it is an important cause of severe infection in neonates, pregnant women, elderly and immunosuppressed patients. Listeriosis has unique preference for pregnant women. Maternal listeriosis is a diagnostic challenge, and intrauterine infection can lead to severe complications such as amnionitis, preterm labor, spontaneous abortion, stillbirth and neonatal sepsis. From 2001 to 2005, 16 patients with L. monocytogenes were identified in this hospital; four (25%) were pregnant women. Clinical and laboratory findings are described. There were 3 preterm deliveries and 1 spontaneous second trimester abortion. Three women with listeriosis had no predisposing factors other than pregnancy. One patient was on immunosupressive drugs for ulcerative colitis. Fever was the most common symptom. Infected neonates were most commonly diagnosed with early-onset listeriosis (two cases) or fetal demise (one case). Pregnancy can be the only risk factor for listeriosis. Listeriosis should be considered during the evaluation of febrile syndrome in pregnancy as this condition can be the only risk factor. Blood and amniotic fluid cultures are useful diagnostic tests. Perinatal complications remains high.

Unlabelled: Congenital syphilis (CS) is an important health problem in Chile, with a rate of 0.25/1,000 live newborn (NB) during year 2004. In 2000, the Chilean Ministry of Public Health recommended to perform a screening in cord blood at the moment of delivery. Instead, the Centers for Disease Control and Prevention guidelines recommend the screening in maternal serum since cord blood has up to 5% of false (-) versus 0.5% of maternal serum, both with respect to the NB serum., Objective: Maternal serum and NB cord blood were studied during one year to determine the best screening method at delivery., Methods: RPR was performed and positive results were confirmed by treponemic test (immunochromatographyDetermine, ELISA Captia, Ig and IgM, and MHA-Tp). Serologically confirmed patients were evaluated by the specialist to define CS cases., Results: Between June 1999 and August 2000 2,741 binomies were studied; of these, 37 (1.3%) were RPR reactive and 2.704 were non-reactive. In 11 of the 37 reactive cases, mother and NB were RPR reactive (Group I), in 9 cases the NB was RPR reactive and the mother was non-reactive (Group II), and the other 17 were NB non-reactive and mother reactive (Group III). In group I, 7/11 (64%) were true (+)s and 4/11(36%)) false (+)s of RPR. In group II, 9/9 (100%) corresponded to false (+)s of RPR in cord blood, and in group III, 11/17 (65%) corresponded to false (+)s of RPR in maternal blood but 6/17 (35%) were found to be cases of syphilis during pregnancy. Three of them were not treated opportunely and were designed as CS. In total 9 NB corresponded to CS (6 in group I and 3 in group III). If the screening had been performed only in cord blood, three NB with CS would have not been diagnosed., Conclusion: Even when maternal serum has a high rate of false (+)s, it has better sensitivity than cord blood for the diagnosis of CS, thus it is suggested to perform the screening at delivery with maternal serum instead of cord blood samples.

Introduction: The diagnostic difficulties of brucellosis makes the evaluation of new diagnostic tests necessary., Objectives: Evaluation of different commercial tests in the serological diagnosis of brucellosis by ELISA and immunocapture antibodies in a clinical series of patients with brucellosis of the Health Network of the Catholic University of Chile., Methods: All the serums received in the Laboratory of Microbiology for suspicion of brucellosis during five years were studied. Two groups were obtained, one that fulfilled diagnostic criteria for brucellosis [clinical evidence, and/or positive blood culture and/or seroagglutination test (SAT) in titers > 1/160] and the control group. Each serum sample was analyzed using irnmunocapture-agglutination test (Brucellacapt), ELISA IgM and IgG., Results: Of 10 patients with brucellosis, the serologic results were: 8/10 positives for ELISA IgG, 7/10 for Brucellacapt and SAT, and 5/10 for ELISA IgM., Discussion: ELISA IgG alone was superior than SAT. The combination ELISA IgG/ Brucellacapt reaches the best detection performance (9/10) and can be an alternative to SAT.

Background: Metallo-beta-lactamases (MBL) confer high resistance to carbapenems in Pseudomonas aeruginosa (Psae). They are encoded in mobile elements of different genes (VIM, IMP, SMP, GIM), along with other resistance genes., Aim: To detect the presence of MBL in imipenem resistant Psae strains., Material and Methods: Fifty-nine imipenem resistant Psae strains isolated from January 2004 to August 2005 in a University Clinical Hospital, were included. The presence of MBL was studied by Etest (phenotypic) and genotypic polymerase chain reaction (PCR) methods. To rule out a nosocomial outbreak, MBL positive strains were studied by pulse field gel electrophoresis., Results: The presence of MBL was detected in eleven strains. AH were type VIM and were not clonally related. There was no concordance between phenotypic and genotypic MBL detecting methods. All the strains were also multiresistant., Conclusions: The presence of MBL was detected in 19% of imipenem resistant Psae strains.

We report the first case of bacillary angiomatosis due to Bartonella quintana affecting a Chilean a HIV positive patient in Chile. He was a 27 years old, heterosexual male, indigent man known to be HIV positive serological status known from September, 2003, under irregular medical control. On April, 2005, he presented a progressive abscess in the frontal region and erythematous papules in the extremities, that extended to face, thorax and mucoses, becoming nodular and violaceous lesions. Bacillary angiomatosis diagnosis was initially sustained on account of the clinical manifestations, and was confirmed by serology and Warthin Starry staining from a skin biopsy. The etiological agent was identified as Bartonella quintana through universal RPC performed from a cutaneous nodule to detect 16S rRNA gen. Azithromycin plus ciprofloxacin was started, besides of anti retroviral therapy antiretroviral, with the lesions being progressively disappearing.

Campylobacter infection is one of the most frequent causes of gastroenteritis in the world and the third in Chile according to some studies. The routinary culture for Campylobacter in our country is not performed because of its high cost, and it is known, that the Hucker stain is a reasonable screening alternative. The objective of this study was to know the utility of the Hucker stain and estimate the frequency of Campylobacter in stool samples. A total of 5,750 stool samples received in the Catholic University Health Net Microbiology Laboratories, from March 2002 to May 2004, were studied with conventional stool culture and Hucker stain. In order to validate the Hucker stain with culture, during one month, all the stool samples were also studied with Campylobacter culture, with 35% sensitivity and 100% specificity. In 115/5.750 samples (2%), curved bacilli suggesting Campylobacter were observed by Hucker stain, and another 233 enteropathogens (4%) which corresponded to: 151 Salmonella sp, 55 Shigella sp, 25 enterohemorrhagic E coli, and 2 Yersinia sp were isolated. When analyzing the patients in whom the Hucker stain was positive, 62.2% were younger than 5 years and of these, 63.8% were infants. We conclude that the Hucker stain is a simple and specific method, although not very sensitive, that allows us to increase the yield of diagnosing enteric pathogens in a 33%. Campylobacter sp was in the second place after Salmonella sp in stool samples, and most frequent in young children. The active search for Campylobacter by means of culture is fundamental in the diagnosis of acute diarrhea.

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 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)., Conclusions: All studied pathogens were sensible to telithromycin in vitro. This antimicrobial is an alternative for the treatment of community acquired respiratory infections.

Background: Leptospirosis is a zoonotic disease and its incidence is known in Chile since 2002, when it was incorporated as a disease that must be reported to health authorities. A serologic survey for leptospirosis was performed in humans and animals from a farm in a semi urban area in Santiago Chile, after the death of a farmer due to Weil disease in that place., Aim: To report the prevalence of antibodies against leptospirosis and to determine exposure to infection risk factors in the humans and domestic animals studied in this survey., Material and Methods: Antibodies were detected by IgM immunodot and indirect haemagglutination test in 61 humans (43 male, aged 5 to 70 years) and by microscopic agglutination test (MAT) in 44 animals. A questionnaire was applied to determine their exposure to risk factors for infection with Leptospira., Results: Seventy two percent of the studied population were farm workers and 70% had activities that required contact with water from canals, 41% cleaned closed places where rodents were present. Other risk factors detected were lack of sewage and waste disposal, high level of rodent infestation and disposal of faeces into canals used for watering. Two humans (3.3%) and six animals (1 bovine and 5 rodents) had positive antibodies. Among animals, antibodies against Leptospira serovar pomona and icterohaemorragiae were detected., Conclusions: In Chile, leptospirosis exists not only in rural areas but semi urban ones close to Santiago, although the prevalence is low. Education is necessary among semi urban population to avoid infection.

Background: In Chile, the emergence of drug-resistant strains of Streptococcus pneumoniae has complicated treatment decisions and may lead to treatment failures., Aim: to examine antimicrobial resistance trends among pneumococcal isolates from the Catholic University Hospital between 1997 and 2003., Material and Methods: During a seven-year period, we examined 901 strains of S. pneumoniae isolated from sterile and non-sterile samples from adult and pediatric population., Results: Overall, 20% of isolates showed intermediate resistance to penicillin (MIC: 0.12-1 microg/ml) y 10.8% high level of resistance to penicillin (MIC > or = 2 microg/ml). Pneumococcal resistance to penicillin did not change significantly during the study period, but it was more common in pediatric patients and isolates from non-sterile samples. No isolate had a MIC > or = 8 microg/ml for penicillin. Twenty one percent of pneumococcal strains were resistant to erythromycin, 41.6% to trimethoprim-sulfamethoxazole and 3.6% to chloramphenicol. Macrolides resistance tended to increase between 1997 and 2003. Fourteen percent of strains showed intermediate resistance (MIC: 1 microg/ml) and 2.5%, a high level of resistance to cefotaxime (MIC: > or = 2 microg/ml). No isolate had a CIM > or = 4 microg/ml for cefotaxime. Among those isolates with intermediate or high level of resistance to penicillin, there were significantly more isolates highly resistant to erythromycin, trimethoprim-sulfamethoxazole and cefotaxime., Conclusions: Multidrug-resistant pneumococci are common and are increasing in our country, particularly in pediatric population, probably associated to indiscriminate ambulatory prescription of antimicrobials.