700,000 years of tropical Andean glaciation.

Our understanding of the climatic teleconnections that drove ice-age cycles has been limited by a paucity of well-dated tropical records of glaciation that span several glacial-interglacial intervals. Glacial deposits offer discrete snapshots of glacier extent but cannot provide the continuous records required for detailed interhemispheric comparisons. By contrast, lakes located within glaciated catchments can provide continuous archives of upstream glacial activity, but few such records extend beyond the last glacial cycle. Here a piston core from Lake Junín in the uppermost Amazon basin provides the first, to our knowledge, continuous, independently dated archive of tropical glaciation spanning 700,000 years. We find that tropical glaciers tracked changes in global ice volume and followed a clear approximately 100,000-year periodicity. An enhancement in the extent of tropical Andean glaciers relative to global ice volume occurred between 200,000 and 400,000 years ago, during sustained intervals of regionally elevated hydrologic balance that modified the regular approximately 23,000-year pacing of monsoon-driven precipitation. Millennial-scale variations in the extent of tropical Andean glaciers during the last glacial cycle were driven by variations in regional monsoon strength that were linked to temperature perturbations in Greenland ice cores1; these interhemispheric connections may have existed during previous glacial cycles.

Preservation of the inferior alveolar vasculonervous bundle in mandibular resective therapies: systematic review and report of two cases.

BACKGROUND: Segmental surgical resection is a frequently indicated procedure to treat aggressive mandibular tumors. One of the most important complications derived from this technique is permanent paresthesia of the inferior alveolar nerve (IAN), which significantly affects the quality of life of patients who experience it. This could be avoided through maneuvers that preserve the IAN. The objective of this paper is to review the main techniques for IAN preservation and to present 2 cases with the technique used by the author. MATERIAL AND METHODS: A systematic review was performed according to the PRISMA guidelines, apropos of two clinical cases reported in this study. The MEDLINE/PubMed and Scopus databases were searched. Several variables were considered and are presented in detail in the form of tables and figures. In addition, 2 case reports with NAI preservation techniques are presented. RESULTS: 13 articles were finally obtained for analysis. 127 patients were evaluated, reporting mandibular resections associated with various pathologies. Various surgical techniques were used, all with the same goal of maintaining the IAN. In most of the patients, the maintenance of sensitivity was achieved, which was verified with different methods. CONCLUSIONS: Preservation of the IAN in maxillofacial surgical procedures where surgical resection of the mandibular bone has been performed is an alternative that has demonstrated successful results in terms of reducing postoperative sequelae and is currently positioned as a necessary and feasible procedure.

CO Oxidation Catalytic Effects of Intrinsic Surface Defects in Rhombohedral LaMnO3.

There is an ongoing effort to replace rare and expensive noble-element catalysts with more abundant and less expensive transition metal oxides. With this goal in mind, the intrinsic defects of a rhombohedral perovskite-like structure of LaMnO3 and their implications on CO catalytic properties were studied. Surface thermodynamic stability as a function of pressure (P) and temperature (T) were calculated to find the most stable surface under reaction conditions (P=0.2 atm, T=323 K to 673 K). Crystallographic planes (100), (111), (110), and (211) were evaluated and it was found that (110) with MnO2 termination was the most stable under reaction conditions. Adsorption energies of O2 and CO on (110) as well as the effect of intrinsic defects such as Mn and O vacancies were also calculated. It was found that O vacancies favor the interaction of CO on the surface, whereas Mn vacancies can favor the formation of carbonate species.

[Adherence to COVID-19 trasmission prevention measures among health care workers]. / Prevención en la transmisión de Coronavirus-19: ¿qué tan preparado está el personal de salud en Chile?

BACKGROUND: COVID-19 is highly transmissible, thus requiring strict measures to prevent its propagation. AIM: To report a survey about self-reported adherence to recommendations aimed to reduce the transmission of COVID-19, among health care personnel. MATERIAL AND METHODS: A cross-sectional survey among health professionals about adherence to recommendations to prevent COVID-19 transmission was carried out in a public hospital in Chile. The survey had 11 questions and was developed using Delphi methodology, according to the recommendations of the World Health Organization and the Centers for Disease Control. RESULTS: The survey was answered by 137 of 155 invited workers. Hand washing, use of personal protection equipment, use of the elbow or tissue to sneeze, out-of-hospital hand washing and exclusive use of the uniform in the hospital, had an adherence of over 90%. The adherence to face touching avoidance during working hours, and face mask use in the public areas, was over 50%. No statistical differences were observed between gender or professionals. CONCLUSIONS: The adherence reported by health care workers was adequate in most of the evaluated recommendations.

Grading of moyamoya disease allows stratification for postoperative ischemia in bilateral revascularization surgery.

BACKGROUND: Moyamoya disease (MMD) may be graded based on DSA, the presence of ischemia in MRI and cerebrovascular reserve capacity allowing the prediction of ischemic symptoms in patients. Cerebral ischemia represents a severe complication in revascularization surgery. Focusing on different clinical features of hemodynamic impairment, MMD grading may allow prediction of ischemic complications. It was the aim to analyze whether MMD grading stratifies for ischemic complications in revascularization surgery for MMD. METHOD: In 37 MMD patients a bilateral, standardized, one-staged revascularization approach consisting of STA-MCA bypass/encephalomyosynangiosis (EMS) and single EMS on the contralateral hemisphere was performed. Clinical data including DSA, MRI and rCBF (Xenon-CT) studies were assessed and used for grading MMD. All patients were observed on the ICU for at least 24 h and received CT imaging on the first postoperative day and in case of neurological deterioration. Ischemic complications were analyzed until the day of discharge and at 6-month follow-up. RESULTS: Grading of MMD revealed 11 hemispheres (15 %) as grade I, 33 hemispheres (44 %) as grade II and 30 hemispheres (41 %) as grade III. Eight ischemic complications were observed (11 %). MMD grading demonstrated a significant correlation with ischemic complications: 0 complications in grade I, 3 in grade II (9 %) and 5 in grade III hemispheres (16 %; p < 0.05, Fisher's exact test). CONCLUSIONS: The proposed grading system allows to stratify for ischemic complications in MMD patients that receive bilateral, one-staged revascularization surgery. Future studies will have to investigate its use for predicting ischemic complications in other revascularization strategies for MMD.

Oculopalpebral prosthesis prototype design using the additive manufacturing technique: A case study.

Three-dimensional (3D) printing technology has advanced for applications in the field of reconstructive surgery. This study reports the application of a comprehensive methodology to obtain an anatomical model, using computed tomography and 3D printing, to treat a patient with cancer who designed a prototype oculopalpebral prosthesis for the reconstruction of the affected area of the face (left eye). A personalized prototype was obtained, which adapted to the face of the person, and improved the aesthetics and quality of life. The applied techniques helped to make definitive prostheses using materials that could be permanent. The training and tests carried out in this study favored the understanding and assimilation of the technology and the possibility of applying it to patients in need of facial prosthetic rehabilitation.

Clinical importance of neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and systemic immune-inflammation index in dogs with leishmaniasis.

Leishmaniasis is a zoonotic disease caused by Leishmania spp., impacts multiple systems and organs. While hematological and biochemical profiles aren't definitive for diagnosis, recent studies have identified the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII) as predictors of morbidity and mortality in critically ill human and dog patients. This study examined 100 dogs diagnosed with leishmaniasis, categorized by the International Renal Interest Society (IRIS) stages 1-4. Additionally, the dogs were divided based on whether they survived less or more than one year (L1Y and G1Y). Control group consisted of 43 dogs. The NLR increased as the disease progressed (IRIS 1-4), presenting statistically significant differences (P<0.05) when compared to the control group (2,37±2,08) IRIS 3 and 4 (4,59±13,39 and 6,99±12,86, respectively), and G1Y and L1Y (3,60±4,02 and 4,87±5,82, respectively). Significant changes in SII were only evident in short-term survivors (L1Y 951,93±1402) and advanced renal disease cases (IRIS 4 stage 1073,68±1901,09). Conversely, PLR remained largely unchanged. In conclusion, these results suggest that the neutrophil-to-lymphocyte ratio (NLR) and systemic immune-inflammation index (SII) may serve as potential markers for assessing disease progression and prognosis in dogs diagnosed with leishmaniasis.

A performance analysis of the presence of malignant circulating prostate cells as a predictive factor for the detection of prostate cancer in the first, second and third prostate biopsy.

OBJECTIVES: Serum prostate specific antigen and digital rectal examination are the tests used as screening tests to detect prostate cancer. However, only approximately 30% of men with suspicion of cancer have it confirmed on prostate biopsy, and not all of these need treatment. Detection of circulating tumor cells in localized prostate cancer has given variable results, but it could be a useful complementary screening tool to detect prostate cancer in men with abnormal screening tests before the evaluation with prostate biopsy. This may be more so in subsequent biopsies where serum PSA has a decreased diagnostic yield. To evaluate the diagnostic yield of the detection of CPCs as a complementary PC screening test in a population fulfilling criteria for an initial, second and third prostate biopsy for suspicion of PC. METHODS: A prospective screening study of consecutive patients aged 45-80 years presenting to the urologist for PC screening. Inclusion criteria were PSA >4.0 ng/ml, PSA velocity >0.35 ng/ml/year and/or DRE suspicious for cancer. Patients fulfilling inclusion criteria had blood taken for CPC detection and then underwent 12-core transrectal prostate biopsy. Double immune-his-tochemical staining with anti-PSA and anti-P504S was used to detect CPCs. Both cytologist and pathologist were blinded to the results of the biopsy, CPC results and clinical details. The diagnostic yield of the presence or absence of CPC was evaluated; the prostate biopsy was classified as cancer or no-cancer. RESULTS: 282 men participated, 83 undergoing of these undergoing a second and 38 a third biopsy, with a mean age of 66.2 ± 8.9 years and a median serum PSA of 5.10 ng/ml, 5.45 ng/ml and 6.45 ng/ml for first, second and third biopsies. Cancer was detected in 33,6%, 10.8% and 29.0% of first, second and third biopsies respectively, CPCs were detected in 36.9%, 21.7% and 36.8% of the patients. Sensibility, specificity and negative predictive value were 86% ,91% and 94% for the first biopsy, 89%, 87% and 99% for the second and 100% , 89% and 100% for third biopsy respectively. All the CPC determinations were interpretable. There were 11 false negative cases, all with small low grade tumors. Of the 29 men with a false positive CPC, 8/10 had cancer detected in the subsequent biopsy. CONCLUSIONS: The use of CPC detection could be useful as a complementary prostate cancer screening test, especially for excluding cancer, and including patients with indications for repeat biopsies. Men with a false positive CPC detection had a high risk of detecting cancer in the succeeding biopsy.

Implications of taxonomic misidentification for future invasion predictions: Evidence from one of the most harmful invasive marine algae.

Invasive species have been a focus of concern in recent decades, becoming more problematic due to the cumulative impacts of climate change. Understanding the interactions among stress factors is essential to anticipate ecosystems' responses. Hereby, robust modeling frameworks must be able to identify the environmental drivers of invasion and forecast the current and future of their potential distribution. These studies are essential for the management of invasions and to be prepared for the future we are facing. Here we demonstrate that taxonomic misidentifications may lead to absolutely erroneous predictions, by using as an example one of the worst invasive species in the Mediterranean Sea (Lophocladia lallemandii), which has been misidentified for three decades and now is correctly identified. Consequently, and bearing in mind overall trends in species misidentification due to the loss of taxonomic expertise and the presence of cryptic species, among others, attempts to understand and predict species involved in invasion processes must always first consider taxonomic studies.

Occurrence, source estimation, and risk assessment of Polycyclic Aromatic Hydrocarbons in coastal seawaters from the Quintero Industrial Complex (Valparaíso, Chile).

In the 1960s, the Quintero industrial complex was inaugurated in Chile. This began a history of dramatic anthropogenic impacts on the Chilean coast. Among the known, we could mention high atmospheric emissions of chemicals due to combustion processes and frequent oil spills. For this reason, we surveyed the concentrations of fifteen EPAPAHs in the surface coastal waters of the Quintero Bay area in 2015. The levels found are in the range of the highest levels when reviewing the literature (0.97 µg L-1 up to 9.84 µg L-1). The highest levels were found in the vicinity of the industrial complex and decreased in the other two zones. The concentration of individual compounds significantly exceeds the levels recommended by the EPA (Environmental Protection Agency) and the EU water framework directive (WFD). The risk estimations revealed that PAH concentrations represent high-risk for wildlife. Molecular ratios of PAHs were used to identify the possible sources, being these were mainly of pyrogenic origin, agreeing with an origin in the combustion of wood, coal, grass, and fossil fuels. This study contributes to the first data for surface water in a country's highly impacted industrial coastal area.

Finite element analysis of a customized implant in PMMA coupled with the cranial bone.

This computational study investigates the effect of the Von Misses stresses and deformations distribution generated by coupling a customized cranial implant with its fixation system for anchoring in the cranial bone of a specific patient. Three simulations were carried out under static loads, in different areas of the implant and during the rest-activity; and another three simulations were considered preset maximum intracranial pressures. Anatomical models were obtained by computed tomography. The design of the device to be implanted was carried out by applying reverse engineering processes, from the corresponding computer-aided design (CAD) model of the bone structure of interest. Likewise, the anchoring system was modeled in detail. Loads were applied at three points on the custom implant. The stress distribution on the artificial plate and the implant-natural bone interface was analyzed. The distribution of the stresses caused by the internal load states on the plate and the anchoring system was also studied. The neurocranial reconstruction with the customized polymethylmethacrylate (PMMA)-based implant and the finite element analysis demonstrated that the fixation and coupling system of the bone-implant interface guarantees adequate protection for the internal structures of the restored area. In addition, the custom-designed and placed implant will not cause non-physiological harm to the patient. Nor will failures occur in the anchoring system.

[Evaluation of the Aspergillus Galactomannan ag VircliaR Monotest test as an alternative to Platelia™ Aspergillus EIA kit]. / Evaluación de la prueba Aspergillus Galactomannan Ag VircliaR Monotest como alternativa a kit Platelia™ Aspergillus EIA.

BACKGROUND: The Aspergillus Galactomannan Ag Virclia® (GMVClia) test is a monotest and automated galactomannan technique based on chemiluminescent immunoassay (CLIA). AIM: To evaluate the performance of the GM-VClia test in serum and bronchioalveolar lavage (BAL) samples previously processed with the Platelia ™ Aspergillus EIA kit (GM-Plat). METHODS: 56 samples of serum 40 from BAL (some of them with galactomaman determination in both samples), from patients with pulmonary diseases, hematological diseases, SLE, Covid-19 and tumors, among others, were studied. Thirteen patients had invasive aspergillosis (1 proven and 12 probable). RESULTS: The correlation between both methods for serum and BAL was r = 0.8861 p < 0.0001 and r = 0.6368 p < 0.001, respectively. There was a global concordance of 67.7% (65/96), being 85.7% (48/56) in sera and 42.5.0% (14/49) in BAL. By raising the cut-off point in LBA by GM-VClia, the agreement increased to 85.7%. CONCLUSION: A greater correlation and concordance was observed in sera than in BAL. The GM-VClia kit had a higher sensitivity and NPV than the GM-Plat kit. The disadvantages of GM-VClia are the "doubtful" category, which makes interpretation difficult and that with the current cut-off points in LBA the correlation with GM-Plat is lower. The advantages are its greater sensitivity, ease of processing and faster results.

Proposal for a new grading of Moyamoya disease in adult patients.

BACKGROUND: Moyamoya disease (MMD) is graded based on digital subtraction angiography (DSA) with limited clinical applications. The aim was to identify clinically relevant parameters that may be used to develop a novel MMD grading system. METHODS: In 40 MMD patients bilateral revascularization surgery was performed. Clinical data including DSA, MRI and regional cerebral blood flow studies were assessed. χ(2) test corrected for dependency of measurements at the same subject and analysis of receiver operating characteristics were used to identify key parameters. Grading system included: DSA (stenosis/occlusion = 1 point; stenosis/occlusion + intracranial compensation = 2 points; stenosis/occlusion + intracranial compensation + extra-intracranial compensation = 3 points), MRI (no sign of ischemia = 0 points; signs of ischemia = 1 point) and cerebrovascular reserve capacity (CVRC > -5% = 0 points; CVRC < -5% = 2 points). MMD grade I referred to 1-2 points, grade II to 3-4 and grade III to 5-6 points. RESULTS: DSA, MRI and CVRC were dependent factors associated with the occurrence of clinical symptoms. Receiver operating characteristics analysis indentified the grading system as superior to each single parameter in predicting clinical symptoms. Fourteen hemispheres were graded as mild (grade I), 35 as moderate (grade II) and 31 as severe (grade III); 21% of grade I, 63% of grade II and 93% of grade III hemispheres were clinically symptomatic. CONCLUSIONS: The proposed grading system allows to stratify for clinical symptomatology in MMD patients. Future studies will have to investigate its value for assessing clinical symptoms and treatment risks.

Characterization of direct and indirect cerebral revascularization for the treatment of European patients with moyamoya disease.

BACKGROUND: The best revascularization strategy for moyamoya disease (MMD) remains unknown. Our aim was to characterize angiographic revascularization effects of a bilateral standardized revascularization approach, consisting of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass and encephalomyosynangiosis (EMS) on one hemisphere and single EMS on the contralateral hemisphere of each patient, and to compare the effects of both revascularization strategies on cerebral hemodynamics. METHODS: In 30 patients (18 females/12 males, age 8-63 years), standardized revascularization was performed. Digital subtraction angiography was performed preoperatively and at 7 days, 6 months and 12 months postoperatively. STA-MCA and EMS functions were graded I (poor), II (medium) or III (extensive) according to angiographic aspects. In 20 patients, cerebrovascular reserve capacity (CVRC) was assessed pre- and postoperatively (at 12 months) using xenon CT. RESULTS: After 12 months, STA-MCA/EMS function was grade 1 in 40/40%, grade 2 in 27/26%, and grade 3 in 27/10% of hemispheres, respectively. Twelve months after surgery, single EMS showed grade I in 37%, grade II in 27%, and grade III in 20% of hemispheres. Combined revascularization improved CVRC significantly compared to preoperative measurement (preoperative: 16.5 ± 34.6% vs. postoperative: 60.8 ± 64.22%; p < 0.05). Single EMS did not improve CVRC significantly (preoperative: 21.8 ± 35.9% vs. postoperative: 34.8 ± 63.0%; p < 0.05). CONCLUSIONS: Combined and indirect revascularization may be successfully applied in a bilateral standardized approach. STA-MCA/EMS is superior to single EMS in restoring CVRC in adult MMD patients.

Diagnostic performance of malignant prostatic cells detection in blood for early detection of prostate cancer: comparison to prostatic biopsy.

OBJECTIVES: Serum prostate specific antigen and digital rectal examination are the tests used as screening tests to detect prostate cancer. However, only approximately 30% of men with suspicion of cancer have it confirmed on prostate biopsy, and not all of these need treatment. Detection of circulating tumor cells in localized prostate cancer has given variable results, but it could be a useful complementary screening tool to detect prostate cancer in men with abnormal screening tests before the evaluation with prostate biopsy. To evaluate the diagnostic yield of the detection of mCPC as a complementary PC screening test in a population fulfilling criteria for a prostate biopsy for suspicion of PC. METHODS: A prospective screening study of consecutive patients aged 45-80 years presenting to the urologist for PC screening. Inclusion criteria were PSA >4.0 ng/ml, PSA velocity >0.35 ng/ml/year and/or DRE suspicious for cancer. Patients fulfilling inclusion criteria had blood taken for mCPC detection and then underwent 12-core transrectal prostate biopsy. Double immune-histochemical staining with anti-PSA and anti-P504S was used to detect mCPC. Both cytologist and pathologist were blinded to the results of the biopsy, mCPC results and clinical details. The diagnostic yield of the presence or absence of mCPC was evaluated; the prostate biopsy was classified as cancer or no -cancer. RESULTS: 228 men participated, with a mean age of 66.8 ± 8.8 years and a median serum PSA of 5.15 ng/ml. 28.6% of the biopsies were positive for PC, and mCPC were detected in 31.0%of all cases. Sensibility, specificity and negative predictive value were 86.2%, 90.8% and 94.3% respectively. The negative and positive like-lihood ratios were 9.36 and 0.15. In men with a PSA <4.0ngml, 13.3% had cancer detected on biopsy, with a sensibility and specificity for mCPC detection of 83.3% and 84.6% and negative predictive value of 97.1%. All the mCPC determinations were interpretable. There were 9 false negative cases, all with small low grade tumors. CONCLUSIONS: The use of mCPC detection could be useful as a complementary prostate cancer screening test, especially for excluding cancer, including patients with a serum PSA <4.0 ng/ml.

Two unusual cases of canine prostatitis: prostatitis in a castrated dog and preputial oedema in an intact male.

In this study, two unusual presentations of canine prostatitis are described; in the first case a 10-years-old neutered Boxer dog was presented to the Veterinary Teaching Hospital of the University of Extremadura with a complaint of anorexia, apathy and preputial discharge. In the second case, a local veterinarian referred an 8-years-old male Labrador to the Veterinary Teaching Hospital of the University of Extremadura. The dog had a history of pain in the caudal abdomen and preputial oedema. The final diagnosis in both cases was acute prostatitis. It is concluded that although canine prostatitis is a common disease, sometimes can have presentations that may differ from those classically described in the literature.

The history of South American tropical precipitation for the past 25,000 years.

Long sediment cores recovered from the deep portions of Lake Titicaca are used to reconstruct the precipitation history of tropical South America for the past 25,000 years. Lake Titicaca was a deep, fresh, and continuously overflowing lake during the last glacial stage, from before 25,000 to 15,000 calibrated years before the present (cal yr B.P.), signifying that during the last glacial maximum (LGM), the Altiplano of Bolivia and Peru and much of the Amazon basin were wetter than today. The LGM in this part of the Andes is dated at 21,000 cal yr B.P., approximately coincident with the global LGM. Maximum aridity and lowest lake level occurred in the early and middle Holocene (8000 to 5500 cal yr B.P.) during a time of low summer insolation. Today, rising levels of Lake Titicaca and wet conditions in Amazonia are correlated with anomalously cold sea-surface temperatures in the northern equatorial Atlantic. Likewise, during the deglacial and Holocene periods, there were several millennial-scale wet phases on the Altiplano and in Amazonia that coincided with anomalously cold periods in the equatorial and high-latitude North Atlantic, such as the Younger Dryas.

[An update on antifungal susceptibility testing]. / Actualización en pruebas de susceptibilidad antifúngica.

Due to increasing of invasive fungal infections and emergeney of antifungal drugs resistant fungi, standardized methods of antifungal susceptibility testing (AST) have been developed. The Clinical Laboratory Standards Instutute (CLSI) and the European for Committee Antimicrobial Susceptibility Testing (EUCAST) have guidelines for susceptibility of yeasts by broth microdilution (M27-A2 and E. Dis. 7.1 documents, respectively). Both are equivalent, although they present methodological and interpretative breakpoints differences. In addition, the CLSI have the M38-A (for filamentous fungi) and M44-A (disk diffusion) documents, whereas EUCAST is developing a document for Aspergillus spp. Furthermore, commercial methods are available that display good correlation with the methods of reference such as E-test, Sensititre and Vitek2. The interpretation of the results must be careful because the determination of the minimum inhibitory concentration (CIM) is difficult for fungi, there are host factors involved and not always there is a correlation between MIC and clinical outcome. Due to these methods are laborious and require trained personnel, to ask for AST to a reference laboratory is recommendable.

[Multicenter study on the monitoring of in vitro susceptibility to tigeeyeline in Santiago, Chile]. / Estudio multicéntrico de la vigilancia de la susceptibilidad in vitro a tigeciclina en Santiago de Chile.

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.