Characteristics of Gram-positive cocci infection and the therapeutic effect after liver transplantation / 中南大学学报(医学版)

OBJECTIVES@#Gram-positive cocci is the main pathogen responsible for early infection after liver transplantation (LT), posing a huge threat to the prognosis of liver transplant recipients. This study aims to analyze the distribution and drug resistance of Gram-positive cocci, the risk factors for infections and efficacy of antibiotics within 2 months after LT, and to guide the prevention and treatment of these infections.@*METHODS@#In this study, data of pathogenic bacteria distribution, drug resistance and therapeutic efficacy were collected from 39 Gram-positive cocci infections among 256 patients who received liver transplantation from donation after citizens' death in the Third Xiangya Hospital of Central South University from January 2019 to July 2022, and risk factors for Gram-positive cocci infection were analyzed.@*RESULTS@#Enterococcus faecium was the dominant pathogenic bacteria (33/51, 64.7%), followed by Enterococcus faecalis (11/51, 21.6%). The most common sites of infection were abdominal cavity/biliary tract (13/256, 5.1%) and urinary tract (10/256, 3.9%). Fifty (98%) of the 51 Gram-positive cocci infections occurred within 1 month after LT. The most sensitive drugs to Gram-positive cocci were teicoplanin, tigecycline, linezolid and vancomycin. Vancomycin was not used in all patients, considering its nephrotoxicity. Vancomycin was not administered to all patients in view of its nephrotoxicity.There was no significant difference between the efficacy of daptomycin and teicoplanin in the prevention of cocci infection (P>0.05). Univariate analysis indicated that preoperative Model for End-Stage Liver Disease (MELD) score >25 (P=0.005), intraoperative red blood cell infusion ≥12 U (P=0.013) and exposure to more than 2 intravenous antibiotics post-LT (P=0.003) were related to Gram-positive cocci infections. Multivariate logistic regression analysis revealed that preoperative MELD score >25 (OR=2.378, 95% CI 1.124 to 5.032, P=0.024) and intraoperative red blood cell transfusion ≥ 12 U (OR=2.757, 95% CI 1.227 to 6.195, P=0.014) were independent risk factors for Gram-positive cocci infections after LT. Postoperative Gram-positive cocci infections were reduced in LT recipients exposing to more than two intravenous antibiotics post-LT (OR=0.269, 95% CI 0.121 to 0.598, P=0.001).@*CONCLUSIONS@#Gram-positive cocci infections occurring early after liver transplantation were dominated by Enterococcus faecalis infections at the abdominal/biliary tract and urinary tract. Teicoplanin, tigecycline and linezolid were anti-cocci sensitive drugs. Daptomycin and teicoplanin were equally effective in preventing cocci infections due to Gram-positive cocci. Patients with high preoperative MELD score and massive intraoperative red blood cell transfusion were more likely to suffer Gram-positive cocci infection after surgery. Postoperative Gram-positive cocci infections were reduced in recipients exposing to more than two intravenous antibiotics post-LT.

Identificación directa de microorganismos a partir de hemocultivos positivos utilizando espectrometría de masas (MALDI-TOF MS) / Direct identification of microorganisms in positive blood culture bottles by mass spectrometry (MALDI-TOF MS)

Resumen La espectrometría de masas (MALDI-TOF MS) permite la identificación de microorganismos directamente de las colonias en pocos minutos. En este estudio se ha desarrollado y evaluado un protocolo reducido para identificar microorganismos directamente de las botellas de hemocultivos positivos en 30 minutos con una alta sensibilidad y especificidad, utilizando MALDITOF. Un total de 2535 hemocultivos positivos fueron estudiados por el método directo de MALDI-TOF MS, a partir de una alícuota de sangre de las botellas y el método de colonia, utilizando los cultivos desarrollados en medios sólidos. Del total de hemocultivos positivos incluidos en este estudio, 2381 (93,9%) fueron monomicrobianos y 146 (5,8%) polimicrobianos. Mil trescientos treinta (55,9%) de los aislamientos correspondieron a cocos gram positivos, 922 (38,7%) a bacilos gram negativos, 60 (2,5%) a anaerobios, 36 (1,5%) a bacilos gram positivos y 13 a levaduras. La concordancia global entre ambos métodos fue del 81,7% a nivel de especie (90,0% para bacilos gram negativos, 76,7% para cocos gram positivos y 33,3% para bacilos gram positivos). Se identificó al menos un germen en el 88% de las botellas positivas con desarrollo polimicrobiano. Los resultados del presente estudio demostraron que el protocolo basado en MALDI-TOF MS permite la identificación microbiana directamente de hemocultivos positivos en un tiempo corto, con una alta precisión, con excepción de los bacilos gram positivos.

Abstract Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) enables the identification of microorganisms directly from colonies within minutes. In this study this technology was adapted and tested for use with blood culture bottles, thus allowing identification in 30 minutes once the blood culture is detected as positive by the automate. A total of 2535 blood culture bottles reported as positive were tested by MALDI-TOF MS directly from positive blood culture bottles and colonies. A total of 2381 (93.9%) and 146 (5.8%) of the positive blood cultures were monomicrobial and polymicrobial, respectively. And 1330 (55.9%), 922 (38.7%), 60 (2.5%), 36 (1.5%) and 13 of the isolates were gram-positive cocci (GPC), gram-negative bacilli (GNB), anaerobic bacteria, gram-positive bacilli (GPB) and yeast respectively. Concordance between both methods was 81.7% (76.7% of GPC, 90% of GNB, 74.2% of anaerobic bacteria and 33.3% of GPB) in monomicrobial cultures. Eighty eight per cent of the polymicrobial cultures were identified correctly in at least one of the two bacteria. The results of the present study show that this fast, MALDI-TOF MS based method allows microbial identification directly from positive blood culture in a short time, with a high accuracy, with the exception of gram-positive bacilli.

Resumo A espectrometria de massa (MALDI-TOF MS) permite a identificação de microorganismos diretamente das colônias em minutos. Nesse estudo, foi desenvolvido um protocolo reduzido para identificar microrganismos diretamente das garrafas de hemoculturas positivas em 30 minutos com alta sensibilidade e especificidade, utilizando MALDI-TOF. Um total de 2535 hemoculturas positivas foram relatadas -o método direto de MALDI-TOF MS, a partir de uma alíquota de sangue dos vidros e o método de colônia, a partir das culturas desenvolvidas em meios sólidos. Do total de hemoculturas positivas incluídas neste estudo, 2.381 (93,9%) eram monomicrobianas e 146 (5,8%) eram polimicrobianas. Mil trezentos e trinta (55,9%) dos isolados corresponderam a cocos gram-positivos, 922 (38,7%) bacilos gram-negativos, 60 (2,5%) anaeróbios, 36 (1,5%) bacilos gram-positivos e 13 leveduras. A concordância geral entre os dois métodos foi de 81,7% em nivel de especie (90,0% para bacilos gram-negativos, 76,7% para cocos gram-positivos e 33,3% para bacilos gram-positivos). Pelo menos um germe foi identificado em 88% dos vidros positivos com desenvolvimento polimicrobiano. Os resultados do presente estudo demonstraram que o protocolo baseado em MALDI-TOF MS permite a identificação microbiana diretamente de hemoculturas positivas em um curto espaço de tempo, com alta precisão, com exceção de bacilos gram-positivos.

Presencia de infección de sitio quirúrgico en procedimientos gineco-obstétricos en un hospital de II nivel de atención, Honduras 2017-2018 / Presence of surgical site infection in obstetric-gynecological procedures in a level II care hospital, Honduras 2017-2018

OBJETIVO: Identificar la presencia de infección de sitio quirúrgico y factores de riesgo en pacientes sometidas a cirugías Gineco-Obstétricas de forma programada o de urgencia en un hospital de II nivel de atención en Honduras. METODOLOGÍA: Estudio observacional, descriptivo, retrospectivo; recopilando 226 fichas del registro de infección de sitio quirúrgico recuperadas de los expedientes clínicos brindados por el servicio de estadística del Hospital Mario Catarino Rivas. Captando pacientes sometidas a cirugías Gineco-Obstétricas, durante el 2017 y 2018. RESULTADOS: 99 fichas cumplieron los criterios de inclusión, reportando una edad de 24 años [RIQ, 19,0 - 30,0], peso 82,0 kg [RIQ, 51,7 - 98,25], talla 154 cm [150,0 - 158,0] y el IMC de 25,8 ± 3,6 kg/m2. Un 9,1% presento antecedentes de inmunosupresión. 5,1% presento ISQ. El 55.6% de las cirugías se realizó el mismo día de ingreso del paciente. El tiempo entre la profilaxis antibiótica y el comienzo de la intervención quirúrgica es de 60 minutos [RIQ, 40,0 - 160,0]. La duración de los procedimientos quirúrgicos son de 45 minutos [RIQ, 35,0 - 55,0]. Los microrganismos aislados en los cultivos fueron Cocos gram positivos (2/5), Enterococcus faecalis (1/5), Klebsiella pneumoniae (2/5). CONCLUSIÓN: La presencia de ISQ en cirugías Gineco-Obstétricas del HMCR es del 5.1%, identificando los siguientes factores de riesgo: edad extrema, obesidad, diabetes mellitus, estado inmunitario (VIH), profilaxis antibiótica (temprana); por último, la técnica y el tiempo quirúrgico.

OBJECTIVE: To identify the presence of surgical site infection and risk factors in patients undergoing Gynecological-Obstetric surgeries on a scheduled or emergency basis in a 2nd level of care hospital in Honduras. METHODOLOGY: Observational, descriptive, retrospective study, compiling 226 data sheets of the surgical site infection record recovered from the clinical records provided by the statistics service of the "Hospital Mario Catarino Rivas". Recruiting patients undergoing Gynecological-Obstetric surgeries, during 2017 and 2018. RESULTS: 99 tabs met the inclusion criteria, reporting an age of 24 [RIQ, 19.0 - 30.0], weight 82.0 kg [RIQ, 51.7 - 98.25], size 154 cm [150.0 - 158.0] and BMI of 25.8 ± 3.6 kg/m2. 9.1% have a history of immunosuppression. 5.1% present ISQ. 55.6% of surgeries were performed on the same day as the patient's admission. The time between antibiotic prophylaxis and the onset of surgery 60 minutes [RIQ, 40.0 - 160.0]. Duration of surgical procedures 45 minutes [RIQ, 35.0 - 55.0]. Isolated micro-morphisms in crops were Cocos gram positives (2/5), Enterococcus faecalis (1/5), Klebsiella pneumoniae (2/5). CONCLUSION: The presence of ISQ in HMCR Gynecological-Obstetric surgeries is 5.1%, identifying the following risk factors: extreme age, obesity, diabetes mellitus, immune status (HIV), early antibiotic prophylaxis; finally, technique and surgical time.

Tuberculosis y una Gemella spp: Una combinación indeseable / Tuberculosis and a Gemella spp: An undesirable combination

El género Gemella spp corresponde a cocos gram positivos, anaerobios facultativos, catalasa negativos, no móviles y no formadores de esporas, usualmente comensales de la cavidad oral, que no suelen ser patógenos en pacientes inmunocompetentes. Sin embargo, puede comportarse como germen oportunista en pacientes inmunosuprimidos o con otros factores de riesgo como mala higiene dental, cirugía gastrointestinal, enfermedades metabólicas entre otras, y se asocia con endocarditis, meningitis y en menor medida compromiso pulmonar. La información respecto a la susceptibilidad antimicrobiana es limitada y se asemeja a la de S viridans, por lo que la penicilina y ampicilina son los medicamentos de elección, sin tener claridad en cuanto a duración del tratamiento, usualmente considerando llevar a 4 semanas o hasta el drenaje de la colección. Éste reporte de caso describe una paciente con tuberculosis en tratamiento, que desarrolla una infección invasiva con documentación de empiema y bacteriemia secundaria por Gemella morbillorum, representando la asociación poco común de ésta infección bacteriana con tuberculosis.

Gemella spp. corresponds to gram positive cocci, facultative anaerobes, negative catalase, non mobile and non spore producers, part of colonizing flora of the oral cavity that are not common pathogens in immunocompetent patients. Nevertheless it may behave as an opportunistic germ in immunosuppressed patients or with other risk factors that include bad dental hygiene, bowel surgery, and metabolic diseases among others. It's associated with infections such as endocarditis, meningitis and less frecuently can implicate the lung. The information regarding antimicrobial susceptibility is limited and resembles S viridans, so penicillin and ampicillin are the medications of choice, without being clear about the duration of treatment, usually giving 4 weeks or until collection drain. This case report describes a patient with known tuberculosis diagnosis and under treatment, that develops an invasive infection with empyema and secondary bloodstream infection by Gemella morbillorum, depicting a previously uncommon but described association of this bacterial infection with tuberculosis.

Identifying gram-positive cocci in dermatoscopes and smartphone adapters using MALDI-TOF MS: a cross-sectional study

Abstract Background: The increasingly frequent use of dermoscopy makes us think about the possibility of transfer of microorganisms, through the dermatoscope, between doctor and patients. Objectives: To identify the most frequent gram-positive cocci in dermatoscopes and smartphone adapters, as well as the resistance profile, and to evaluate the factors associated with a higher risk of bacterial contamination of the dermatoscopes. Methods: A cross-sectional study was carried out with 118 dermatologists from Porto Alegre/Brazil between September 2017 and July 2018. Gram-positive cocci were identified by MALDI-TOF MS and habits of use of the dermatoscope were evaluated through an anonymous questionnaire. Results: Of the dermatoscopes analysed, 46.6% had growth of gram-positive cocci on the lens and 37.3% on the on/off button. The microorganisms most frequently found were S. epidermidis, S. hominis and S. warneri. Attending a hospital, using the dermatoscope at the hospital, with inpatients and in the intensive care unit were significantly associated with colonisation by gram-positive cocci. The highest resistance rates were observed for penicillin, erythromycin and sulfamethoxazole-trimethoprim. Study limitations: The non-search of gram-negative bacilli, fungi and viruses. Moreover, the small number of adapters did not make it possible to better define if the frequency differences were statistically significant. Conclusion: Coagulase-negative staphylococci were frequently identified. S. aureus was detected only on the lens.

Endocarditis bacteriana por Kocuria kristinae en un paciente inmunocompetente. Reporte de caso / Bacterial endocarditis by Kocuria kristinae in an immunocompetent patient. Case report

Los miembros del género Kocuria corresponden a cocos Gram positivos ubicuos, generalmente inocuos y que hacen parte de la flora saprófita de un porcentaje importante de la población; ocasionalmente han sido descritos como los agentes responsables de patologías infecciosas, principalmente dentro del contexto de pacientes que concomitantemente cursan con enfermedades crónicas y estados de inmunosupresión. Son escasos los casos reportados como causa de endocarditis en pacientes inmunocompetentes a nivel global por especies de este género. Se expone el caso de una mujer inmunocompetente de 44 años, sin antecedentes de importancia, en quien solo el diagnóstico microbiológico permitió confirmar la presencia de Kocuria kristinae como agente causal de su endocarditis infecciosa; la literatura señala la dificultad existente al momento de diferenciar la endocarditis producida por Staphylococcus spp. versus Kocuria kristinae por su evolución clínica similar, indicando la importancia de la microbiología al momento de identificar y diagnosticar apropiadamente.

Members of the genus Kocuria correspond to ubiquitous, generally harmless, Gram-positive cocci that are part of the saprophytic flora of a significant percentage of the population; occasionally they have been described as the agents responsible for infectious pathologies, mainly in the context of patients who concomitantly have chronic diseases and are under an immunosuppression state. There are few cases reported as a cause of endocarditis in immunocompetent patients globally by species of this genus. We present the case of a 44-year-old immunocompetent woman, with no relevant history, in whom only the microbiological diagnosis confirmed the presence of Kocuria kristinae as the causative agent of her infectious endocarditis; Literature points out the difficulty existing when differentiating endocarditis produced by Staphylococcus spp. versus Kocuria kristinae because of their similar clinical evolution, indicating the importance of microbiology when identifying and diagnosing accurately.

Microorganismos que colonizan los catéteres venosos centrales de los pacientes hospitalizados en el servicio de medicina intern / Microorganisms that colonize the central venous catheters of patients hospitalized in the internal medicine service of the Dr. Miguel Pérez Carreño hospital

La utilización de catéter venoso central produce, en ocasiones, infecciones de tipo local o sistémico, como la bacteriemia no complicada o complicada (bacteriemia persistente, tromboflebitis séptica, endocarditis y otras complicaciones metastásicas). En este estudio se dan a conocer las infecciones ocasionadas por el uso de Catéter Venoso Central (CVC), así como los microorganismos presentes en los pacientes. Métodos: La investigación fue de tipo retrospectivo, descriptivo y de corte transversal, con un diseño de investigación no experimental y tuvo la finalidad de conocer, en forma directa, la realidad de la problemática. Las unidades de observación fueron (188) historias clínicas de los pacientes que ingresaron en el servicio de medicina interna en el hospital Miguel Pérez Carreño en el periodo comprendido entre enero y abril de 2017. Resultados: En 30 de los pacientes se realizó el cultivo de la punta del catéter venoso central. En el 67% no hubo crecimiento de microorganismos, mientras que el 33% crecieron microorganismos a las 24 horas. El 80% de las muestras cultivadas reportan la presencia de Cocos Gram positivos. Un 10% reportaron enterobacterias y un 10% reportan levaduras, finalmente con menor frecuencia pseudomona con un 0%. Conclusiones: Solo 78 pacientes ameritaron la colocación de un catéter venoso central, de los cuales se cultivaron 30 puntas de catéter, encontrándose que solo 10 de las puntas de catéteres dieron positivas para infección con crecimiento bacteriano a las 24 horas, siendo los cocos Gram positivos la principal bacteria aislada en los pacientes con CVC seguidos de enterobacterias(AU)

Intravascular catheterization is used for hemodynamic monitoring, hemodialysis, metabolic and nutritional support, fluid administration, chemotherapy and prolonged antibiotic therapy, blood and derivatives, among others. In this study, infections caused by the use of (CVC) central venous catheter are reported, as well as the microorganisms present in patients. Methods: The research was of a retrospective, descriptive and cross-sectional type, with a non-experimental research design and aimed to know, in a direct way, the reality of the problem. The observation units were (188) clinical records of the patients admitted to the internal medicine service at the Miguel Pérez Carreño Hospital in the period between January and April 2017. Results In 30 of the patients, the culture of the tip of the central venous catheter. In 67% there was no growth of microorganisms, while 33% grew microorganisms at 24 hours. 80% of the cultivated samples report the presence of Gram-positive cocci. 10% reported enterobacteria and 10% reported yeast, finally with less frequency pseudomonas with 0%. Conclusions: Only 78 patients required placement of a central venous catheter, of which 30 catheter tips were cultured, finding that only 10 of the catheter tips were positive for infection with bacterial growth at 24 hours, with Gram-positive cocci. the main bacteria isolated in patients with CVCfollowed by enterobacteria(AU)

Bacterial Endocarditis Caused by Abiotrophia defectiva in a Healthy Adult: A Case Report with Literature Review / 대한임상미생물학회지

Infective endocarditis caused by Abiotrophia defectiva is rarely encountered. A 67-year-old male transferred from a local hospital presented with severe dyspnea and pulmonary edema. Preoperative transthoracic echocardiography revealed severe mitral regurgitation with large vegetation. Blood cultures grew A. defectiva, a gram positive, nutritionally deficient streptococcus variant. Emergent mitral valve replacement through right thoracotomy was performed, and after completing six weeks of antibiotic combination therapy (vancomycin, ampicillin, and gentamicin), the patient recovered fully. Because of the need for prompt surgical treatment and long-term antibiotic therapy and lack of laboratory experience with the organism, physicians and laboratory workers should pay close attention to the possibility of A. defectiva infective endocarditis when gram positive cocci are detected in blood cultures.

Trends in Bloodstream Infections and Antimicrobial Susceptibilities at a University Hospital in Korea Between 2007 and 2016

BACKGROUND: Blood culture is an important method for identifying infectious microorganisms and confirming that a selected antimicrobial treatment is appropriate. In this study, we investigated the annual changes in the frequencies of blood isolates and antibiotic susceptibility test (AST) results. METHODS: We created a large database comprising data on all patient-unique blood cultures obtained from January 2007 through December 2016. Blood specimens were cultured using the BD BACTEC FX system, and species identification and AST were performed using the VITEK 2 system. RESULTS: During the 10-year study period, a total of 203,651 blood culture results were collected. Of these, gram-positive cocci, gram-negative rods, and fungi were isolated in 2.15%, 0.55%, and 0.12% of the blood cultures, respectively. Escherichia coli was the most commonly isolated species (22.8%), followed by Staphylococcus epidermidis (16.8%), Klebsiella pneumoniae (8.1%), and Staphylococcus aureus (8.0%). Fungal species were isolated in 3.0% of all positive blood cultures. Candida albicans was the most commonly isolated species (1.1%), followed by Candida parapsilosis (0.6%). Methicillin resistance was seen in 55.2% of S. aureus isolates. The frequencies of vancomycin-resistant Enterococcus (VRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPA) were 13.1% and 10.9%, respectively. The isolation rates of MRSA, VRE, and CRPA showed different patterns each year. CONCLUSIONS: Among the isolates, E. coli was the most common, followed by S. epidermidis and K. pneumoniae. This study represents a long-term analysis of bloodstream infections, and the results can be used to identify trends in the microorganisms isolated and their drug resistance.

Performance Evaluation of Newly Developed Korean Antimicrobial Susceptibility Testing Panels for MicroScan System Using Clinical Isolates from Teaching Hospitals in Korea / 대한임상미생물학회지

BACKGROUND: Antimicrobial resistant continues to pose a threat to public health. Therefore, rapid and accurate antimicrobial susceptibility testing is very important. The objectives of this study were to evaluate the performance of the MicroScan system (Beckman Coulter, USA) with newly developed Korean Antimicrobial Susceptibility Testing Panels (KSCM panels) for antimicrobial susceptibility testing (AST) against clinical isolates in South Korea. METHODS: Three KSCM panels were designed in this study. For the performance evaluation, a total of 1,325 clinical isolates including 1,027 of Gram-negative bacilli and 298 Gram-positive cocci collected from eight general hospitals in South Korea were used. The results by KSCM panels were compared with those by conventional methods. RESULTS: By KSCM-1 panel for Gram-positive cocci, the rates of categorical agreement (CA) were >90% in all the antimicrobials tested in this study. The rates of major error (ME) were also 90%, ME rates <3%, and VME rates <1.5%. CONCLUSION: The newly developed three KSCM panels for MicroScan system (Beckman Coulter) showed excellent performance in AST against a large number of clinical isolates, and they are applicable to clinical microbiology laboratories.

Is it possible to perform bacterial identification and antimicrobial susceptibility testing with a positive blood culture bottle for quick diagnosis of bloodstream infections?

Abstract INTRODUCTION: Bloodstream infections can be fatal, and timely identification of the etiologic agent is important for treatment. METHODOLOGY: An alternative method, consisting of direct identification and susceptibility testing of blood culture bottles using the automated VITEK 2® system, was assessed. RESULTS: All 37 of the Gram-negative bacilli (GNB) identifications and 57.1% of the 28 Gram-positive cocci (GPC) identifications matched those obtained with standard methods. In susceptibility testing, the agreement was greater than 90%. CONCLUSIONS: This alternative methodology may assist in the early identification and susceptibility testing of GNB. Further research is necessary to develop appropriate methods for GPC.

Globicatella sanguinis Bacteremia in a Korean Patient / 대한임상미생물학회지

Globicatella sanguinis is an unusual pathogen causing bacteremia, meningitis, and urinary tract infection, and can be misidentified as Streptococcus pneumoniae or viridans streptococci due to its colonial morphology. A 76-year-old female patient with hypertension and degenerative arthritis was admitted to the hospital complaining of knee joint pain. Blood culture revealed the presence of Gram-positive cocci, and the isolated organism was equally identified as S. pneumoniae using the MicroScan identification system (Beckman Coulter, USA) and Vitek 2 identification system (bioMérieux, USA). However, the isolate showed optochin resistance based on the optochin disk susceptibility test. The organism was finally confirmed to be G. sanguinis based on 16S rRNA sequencing and hydrogen sulfide production testing. Accurate identification of G. sanguinis isolated from aseptic body fluids including blood is important for appropriate antibiotic selection based on accurate application of interpretative criteria of antimicrobial susceptibility test.

Clinical Evaluation of QMAC-dRAST for Direct and Rapid Antimicrobial Susceptibility Test with Gram-Positive Cocci from Positive Blood Culture Bottles / 대한임상미생물학회지

BACKGROUND: Timely intervention in the treatment of bloodstream infection is important for prescription of appropriate antimicrobials. With prompt determination of the antimicrobial susceptibility of a causative agent, rapid antimicrobial susceptibility test (AST) can help select the appropriate antimicrobial therapy. This clinical study is for evaluation of the clinical performance of the QMAC-dRAST for rapid AST directly from positive blood culture (PBC)s with Gram-positive cocci. METHODS: A total of 115 PBC samples with Gram-positive organisms (76 Staphylococcus spp. and 39 Enterococcus spp.) were evaluated by the QMAC-dRAST system, and their pure culture isolates were evaluated by the MicroScan WalkAway (Beckman Coulter, USA) as the comparative AST system. Thirteen antimicrobial agents were included, and the agreement and discrepancy rates of the QMAC-dRAST system (Quantamatrix Inc., Republic of Korea) compared to the MicroScan WalkAway were calculated. To resolve discrepancies, the broth microdilution method was performed. RESULTS: The QMAC-dRAST system exhibited a categorical agreement rate of 94.9% (1,126/1,187) and an essential agreement rate of 98.3% (1,167/1,187). The QMAC-dRAST system yielded very major (false-susceptible) errors at 1.0% (5/485), major (false-resistant) errors at 1.3% (9/693), and minor errors at 4.0% (47/1,187) compared to the MicroScan WalkAway. The QMAC-dRAST system significantly eliminated 30 hours of total turnaround time by combination of direct inoculation of PBC and an image-based approach. CONCLUSION: The results of the QMAC-dRAST system were highly accurate. Thereby, the QMAC-dRAST may provide essential information to accelerate therapeutic decisions for earlier and adequate antibiotic treatment and patient management in clinical settings.

A Case of Streptococcus gallolyticus subsp. gallolyticus Bacteremia in Liver Cirrhosis

Streptococcus bovis bacteremia in humans has been traditionally associated with infective endocarditis, colorectal cancer, and liver cirrhosis. S. bovis strains were previously categorized by biotype, but since the 2000s, they have been reclassified by DNA homology. We report a case of S. gallolyticus subsp. gallolyticus bacteremia, identified by 16S rRNA sequencing, in a patient diagnosed with liver cirrhosis. A 61-yr-old man with a history of liver cirrhosis presented to the hospital with a complaint of fever. Blood culture revealed the presence of gram-positive cocci, and the isolated organism was identified as S. bovis by the MicroScan identification kit (Beckman Coulter, USA), but as Enterococcus saccharolyticus by the Vitek 2 identification kit (bioMérieux, USA). The organism was finally confirmed as S. gallolyticus subsp. gallolyticus by 16S rRNA sequencing.

Chronic Early-life Stress in Rat Pups Alters Basal Corticosterone, Intestinal Permeability, and Fecal Microbiota at Weaning: Influence of Sex

BACKGROUND/AIMS: Wistar rat dams exposed to limited nesting stress (LNS) from post-natal days (PND) 2 to 10 display erratic maternal behavior, and their pups show delayed maturation of the hypothalamic-pituitary-adrenal axis and impaired epithelial barrier at PND10 and a visceral hypersensitivity at adulthood. Little is known about the impact of early life stress on the offspring before adulthood and the influence of sex. We investigated whether male and female rats previously exposed to LNS displays at weaning altered corticosterone, intestinal permeability, and microbiota. METHODS: Wistar rat dams and litters were maintained from PND2 to 10 with limited nesting/bedding materials and thereafter reverted to normal housing up to weaning (PND21). Control litters had normal housing. At weaning, we monitored body weight, corticosterone plasma levels (enzyme immunoassay), in vivo intestinal to colon permeability (fluorescein isothiocyanate-dextran 4 kDa) and fecal microbiota (DNA extraction and amplification of the V4 region of the 16S ribosomal RNA gene). RESULTS: At weaning, LNS pups had hypercorticosteronemia and enhanced intestinal permeability with females > males while body weights were similar. LNS decreased fecal microbial diversity and induced a distinct composition characterized by increased abundance of Gram positive cocci and reduction of fiber-degrading, butyrate-producing, and mucus-resident microbes. CONCLUSIONS: These data indicate that chronic exposure to LNS during the first week post-natally has sustained effects monitored at weaning including hypercorticosteronemia, a leaky gut, and dysbiosis. These alterations may impact on the susceptibility to develop visceral hypersensitivity in adult rats and have relevance to the development of irritable bowel syndrome in childhood.

Trends in Microorganisms Isolated from Blood Cultures at a Veterans Hospital from 2012 to 2015

Blood culture is important to detecting bacteremia and fungemia in patients with suspected sepsis. We observed a four-year trend of blood culture isolates in the frequency by age group and in vitro antimicrobial susceptibility patterns obtained at VHS Medical Center, the largest veterans hospital in Korea. Blood cultures collected between 2012 and 2015 were analysed retrospectively. Of 68,352 blood specimens, 7,901 isolates were identified during the study period. Seventy-two percent of the isolates were gram-positive cocci, 18% were gram-negative rods, and 6% were fungi. The frequency of bacteremia/fungemia in patients who were 80–89 years old was 43.8%, the highest rate among all age groups, and the mean age of patients diagnosed by blood culture was 77 years old. Coagulase-negative staphylococcus (52.3%), Staphylococcus aureus (8.3%), enterococci (7.5%), Escherichia coli (6.4%), and Klebsiella pneumoniae (3.9%) were the bacteria most commonly isolated. The percentage of methicillin-resistant S . aureus increased in 2015 (76%) relative to that in 2012–2014 (63%–65%), and that of vancomycin-resistant Enterococcus faecium was 17%–22% with no significant changes through time. Among the gram-negative isolates, the ciprofloxacin resistance rate increased to 51.4% (E. coli ) and 31.1% (K. pneumoniae ) in 2015, but imipenem or ertapenem resistance was still very rare, with resistance rates of less than 0.5%. Acinetobacter baumannii showed a high rate of resistance (over 70%) to imipenem and ciprofloxacin throughout the study. In Pseudomonas aeruginosa , the resistance rates of imipenem and ciprofloxacin increased dramatically over time. This analysis confirmed a decrease in antimicrobial susceptibility of gram-negative rods isolated by blood culture.

Accuracy of the VITEK 2 system for a rapid and direct identification and susceptibility testing of Gram-negative rods and Gram-positive cocci in blood samples

The performance of the VITEK 2 system for direct rapid identification and antimicrobial susceptibility testing of the bacteria responsible for blood infections was determined. The isolates studied included 166 Gram-negative rods and 74 Gram-positive cocci from inpatients. Specially treated monomicrobial samples from positive blood culture bottles were directly inoculated into the VITEK 2 system and the results were compared with those from cards inoculated with standardized bacterial suspensions. Compared with the standard method, 95.8% of Gram-negative rods were correctly identified by VITEK 2 and the overall level of agreement between the two methods in susceptibility testing was 92.0%. For Gram-positive bacteria, 89.2% were correctly identified by VITEK 2 and susceptibility testing revealed an overall agreement rate of 91.3%. These results suggest that VITEK2 cards inoculated with fluids sampled directly from positive blood culture bottles are suitable for speedy identification and susceptibility testing of Gram-negative bacilli and Gram-positive cocci

Calcaneal Osteomyelitis due to Non-tuberculous Mycobacteria: A Case Report

Osteomyelitis is a bone infection caused by bacteria or other germs. Gram-positive cocci are the most common etiological organisms of calcaneal osteomyelitis; whereas, non-tuberculous mycobacteria (NTM) are rarely documented. We reported a case of NTM calcaneal osteomyelitis in a 51-year-old female patient. She had been previously treated in many local clinics with multiple local steroid injection over 50 times and extracorporeal shock-wave therapy over 20 times with the impression of plantar fasciitis for 3 years prior. Diagnostic workup revealed a calcaneal osteomyelitis and polymerase chain reaction assay on bone aspirate specimens confirmed the diagnosis of non-tuberculous mycobacterial osteomyelitis. The patient had a partial calcanectomy with antitubercular therapy. Six months after surgery, a follow-up magnetic resonance imaging showed localized chronic osteomyelitis with abscess formation. We continued anti-tubercular therapy without operation. At 18-month follow-up after surgery and comprehensive rehabilitation therapy, she was ambulating normally and able to carry out her daily activities without any discomfort.