Development of a prototypic, field-usable diagnostic tool for the detection of gram-positive cocci-induced mastitis in cattle.

BACKGROUND: Bovine mastitis is one of the most widespread diseases affecting cattle, leading to significant losses for the dairy industry. Currently, the so-called gold standard in mastitis diagnosis involves determining the somatic cell count (SCC). Apart from a number of advantages, this method has one serious flaw: It does not identify the etiological factor causing a particular infection, making it impossible to introduce targeted antimicrobial therapy. This can contribute to multidrug-resistance in bacterial species. The diagnostic market lacks a test that has the advantages of SCC and also recognizes the species of pathogen causing the inflammation. Therefore, the aim of our study was to develop a lateral flow immunoassay (LFIA) based on elongation factor Tu for identifying most prevalent Gram-positive cocci responsible for causing mastitis including Streptococcus uberis, Streptococcus agalactiae and Staphylococcus aureus. RESULTS: As a result, we showed that the assay for S. uberis detection demonstrated a specificity of 89.02%, a sensitivity of 43.59%, and an accuracy of 80.3%. In turn, the second variant - assay for Gram-positive cocci reached a specificity of 95.59%, a sensitivity of 43.28%, and an accuracy of 78.33%. CONCLUSIONS: Our study shows that EF-Tu is a promising target for LFIA and we have delivered evidence that further evaluation could improve test parameters and fill the gap in the mastitis diagnostics market.

Multidrug-Resistant Bacteria Isolated From Surgical Site of Dogs, Surgeon's Hands and Operating Room in a Veterinary Teaching Hospital in Brazil.

Surgical environment can play as a source of multidrug-resistance organism, what can pose as a big threat to the patients and health care professionals. This study aimed to evaluate the prevalence and antimicrobial resistance profile of Gram-positive cocci (GPC) and Gram-negative bacilli (GNB) isolated from the surgical environment. All samples were collected during the intraoperative period of clean/clean-contaminated (G1) and contaminated (G2) surgery. A total of 150 samples were collected from the superficial surgical site in the beginning (n = 30) and the end (n = 30) of the procedure, surgeon's hands before (n = 30) and after (n = 30) antisepsis, and the surgical environment (n = 30). MALDI-TOF MS and antimicrobial susceptibility testing by disk diffusion method were performed for species identification, and determination of the resistance profile. Sixty-eight isolates of GPC and 15 of GNB were obtained. Staphylococcus spp. were the most frequent species isolated from surgical site (55.26% [21/38]), surgeon's hands (46.15% [6/13]), and environment (56.67% [17/30]). GPC were mostly resistance to penicillin (85.71% [54/63]), and erythromycin (77.78% [49/63]), and GNB were mostly resistance to cefazolin (58.33% [7/12]), and azithromycin (58.33% [7/12]). High incidence of multidrug resistance was observed in coagulase-negative staphylococci (86.21% [25/29]), coagulase-positive staphylococci (86.67% [13/15]), Enterococcus spp. (68.42% [13/19]) and Gram-negative bacilli (60% [9/15]). The high rate of resistance of commensal bacteria found in our study is worrying. Coagulase-negative staphylococci are community pathogens related to nosocomial infections in human and veterinary hospitals, their presence in healthy patients and in veterinary professionals represent an important source of infection in the One Health context. Continuous surveillance and application of antimicrobial stewardship programs are essential in the fight against this threat.

Peptoniphilus faecalis sp. nov., isolated from swine faeces.

An obligately anaerobic, Gram-positive, non-motile, coccus-shaped bacterial strain designated AGMB00490T was isolated from swine faeces. 16S rRNA gene sequence-based phylogenetic analysis indicated that the isolate belongs to the genus Peptoniphilus and that the most closely related species is Peptoniphilus gorbachii WAL 10418T (=KCTC 5947T, 97.22 % 16S rRNA gene sequence similarity). Whole genome sequence analysis determined that the DNA G+C content of strain AGMB00490T was 31.2 mol% and moreover that the genome size and numbers of tRNA and rRNA genes were 2 129 517 bp, 34 and 10, respectively. Strain AGMB00490T was negative for oxidase and urease; positive for catalase, indole production, arginine arylamidase, leucine arylamidase, tyrosine arylamidase and histidine arylamidase; and weakly positive for phenylalanine arylamidase and glycine arylamidase. The major cellular fatty acids (>10 %) of the isolate were determined to be C16 : 0 and C18 : 1 ω9c. Strain AGMB00490T produced acetic acid as a major end product of metabolism. Accordingly, phylogenetic, physiologic and chemotaxonomic analyses revealed that strain AGMB00490T represents a novel species for which the name Peptoniphilus faecalis sp. nov. is proposed. The type strain is AGMB00490T (=KCTC 15944T=NBRC 114159T).

Study of Normal Flora in the Pharynx of Healthy Children.

To improve our current understanding of normal flora in children, we investigated bacterial isolates from the pharynx and nasopharynx of 173 and 233 healthy children, respectively. The bacterial isolation rates were compared among three age groups: infants (<1 year), toddlers (1-5 years), and school-aged children (6-15 years). Gram-positive cocci were the predominant bacteria in the pharynx (Streptococcus mitis/oralis, 87.3%; Streptococcus salivarius, 54.3%; Rothia mucilaginosa, 41.6%; Staphylococcus aureus, 39.3%). Among infants, S. salivarius and Neisseria subflava, which are related to the development of teeth, were significantly lower than in the other age groups (P <0.0001, S. salivarius; P <0.01, N. subflava). With the exception of Corynebacterium pseudodiphtheriticum (44.2%, gram-positive rods), gram-negative rods largely predominated the nasopharynx (Moraxella catarrhalis, 32.1%; Moraxella nonliquefaciens, 28.3%). Among toddlers, M. catarrhalis and Streptococcus pneumoniae, which are the most common pathogens in acute otitis media, were significantly higher than in the infant group (P <0.05). Among the bacterial species implicated in pediatric respiratory infections, Streptococcus pyogenes was isolated in 3.5% of the pharyngeal samples. S. pneumoniae and Haemophilus influenzae were isolated in 22.3% and 17.2% of the nasopharyngeal samples, respectively. In conclusion, the normal flora of the respiratory tract differs not only by the sampling site but also by the age group.

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.

Risk for infective endocarditis in bacteremia with Gram positive cocci.

PURPOSE: Infective endocarditis (IE) is a serious complication of bacteremia and is most often caused by Gram positive cocci. We investigated the prevalence of IE in patients where echocardiography was encouraged when bacteremia with Gram positive cocci was present. METHODS: The study included patients with Gram positive cocci bacteremia hospitalized at two Danish hospitals between March and December 2016. Information concerning echocardiography, demographics and bacterial species was collected from the patients' medical files. Patients without echocardiography were followed for 6 months in order to confirm or reject possible IE. RESULTS: The study included 585 patients with Gram positive cocci bacteremia, and echocardiography was performed in 414 (71%) of them. The prevalence of IE in patients with high risk bacteremia, i.e. Staphylococcus aureus, non-beta-hemolytic streptococci, Enterococcus faecalis, and coagulase-negative staphylococci was 16%. Patients with Enterococcus faecalis had the highest prevalence of IE (33%) followed by non-beta-hemolytic streptococci (23%) and Staphylococcus aureus (12%). Among low risk bacteremia the prevalence of IE was 1%. The mean age of patients with IE was 74 years (SD 12.9) and 71% were male. CONCLUSION: These findings strongly support routine echocardiography in patients with high risk bacteremia and non-performance of echocardiography in patients with low risk bacteremia.

Comparison of breakthrough Gram-positive cocci infection during vancomycin vs teicoplanin therapy in patients receiving haematopoietic stem cell transplantation.

WHAT IS KNOWN AND OBJECTIVE: Our previous report indicated that teicoplanin (TEIC) caused fewer adverse effects than vancomycin (VCM) in patients with febrile neutropenia (FN) receiving haematopoietic stem cell transplantation (HSCT). However, we observed breakthrough methicillin-resistant-Staphylococcus haemolyticus (MR-S haemolyticus) infection during TEIC therapy in these patients. In this study, we sought to compare the incidence of breakthrough Gram-positive cocci (GPC) infection during VCM and TEIC therapy in this population. METHODS: A single-centre, retrospective cohort study was conducted. Patients who had received HSCT and were administered VCM (n = 19) or TEIC (n = 38) for FN from 1 September 2011 to 31 August 2019 were enrolled. We compared the incidence of breakthrough GPC infection between the VCM and TEIC groups. RESULTS: Breakthrough GPC infection during glycopeptide therapy in febrile neutropenic patients received HSCT was observed in three patients (7.9%) in the TEIC group but in none of patients (0%) in the VCM group. MR-S haemolyticus with low glycopeptide susceptibility (TEIC MIC = 2-8 µg/mL, VCM MIC = 2-4 µg/mL) was isolated from blood cultures in all patients with breakthrough GPC infections. All breakthrough infections were cured by changing from TEIC to daptomycin (DAP). WHAT IS NEW AND CONCLUSION: The incidence of breakthrough GPC infection during glycopeptide therapy in febrile neutropenic HSCT patients was higher in the TEIC group than in the VCM group. MR-S haemolyticus with low glycopeptide susceptibility was isolated from all patients with breakthrough GPC infection and successfully treated with DAP.

How is the microbial diagnosis of bacterial vertebral osteomyelitis performed? An 11-year retrospective study.

Vertebral osteomyelitis (VOM) is often diagnosed with delays, resulting in poorer outcomes. Microbial documentation is particularly challenging and obtained using blood cultures (BCs) and vertebral biopsies (VBs; CT-guided or surgical). We retrospectively analysed VOM cases in a tertiary reference centre between 2004 and 2015, focusing on how and how quickly microbiological diagnosis was performed. Among 220 VOM, 88.2% had documentation, including Gram-positive cocci (GPC) (70.6%), Gram-negative rods (GNR) (9.3%), anaerobes (3.6%), polybacterial infections (6.7%) and tuberculosis (9.8%). BCs were performed in 98.2% and positive in 59.3%, identifying most GPC (80.3%) and half of GNR (54.6%). VBs were performed in fewer cases (37.7%), but were more frequently positive (68.8% for CT-guided and 81.0% for surgical biopsies). They documented all anaerobes (100.0%), most M. tuberculosis (84.2%) and polybacterial infections (76.9%), and GNR (45.4%). Extra-vertebral samples highly contributed to tuberculosis diagnosis (52.6%, and 15.8% as the only positive sample). Documentations most often followed radiological diagnosis (53.4%). They were obtained earlier by BCs than by VB after first clinical symptoms (median of 14 versus 51 days). Antibiotic treatments were mostly initiated after samplings (88.0%). BCs allow the documentation of most VOM and should be performed without delay in case of clinical or radiological suspicion; however, they may miss 1 out of 5 GPC and 1 out of 2 GNR. VBs have a higher positivity rate and should be rapidly performed if negative BCs. It is likely that delayed and missed diagnoses result from the insufficient use of VB.

Short-course antibiotic regimen compared to conventional antibiotic treatment for gram-positive cocci infective endocarditis: randomized clinical trial (SATIE).

BACKGROUND: Most serious complications of infective endocarditis (IE) appear in the so-called "critical phase" of the disease, which represents the first days after diagnosis. The majority of patients overcoming the acute phase has a favorable outcome, yet they remain hospitalized for a long period of time mainly to complete antibiotic therapy. The major hypothesis of this trial is that in patients with clinically stable IE and adequate response to antibiotic treatment, without signs of persistent infection, periannular complications or metastatic foci, a shorter antibiotic time period would be as efficient and safe as the classic 4 to 6 weeks antibiotic regimen. METHODS: Multicenter, prospective, randomized, controlled open-label, phase IV clinical trial with a non-inferiority design to evaluate the efficacy of a short course (2 weeks) of parenteral antibiotic therapy compared with conventional antibiotic therapy (4-6 weeks). SAMPLE: patients with IE caused by gram-positive cocci, having received at least 10 days of conventional antibiotic treatment, and at least 7 days after surgery when indicated, without clinical, analytical, microbiological or echocardiographic signs of persistent infection. Estimated sample size: 298 patients. INTERVENTION: Control group: standard duration antibiotic therapy, (4 to 6 weeks) according to ESC guidelines recommendations. Experimental group: short-course antibiotic therapy for 2 weeks. The incidence of the primary composite endpoint of all-cause mortality, unplanned cardiac surgery, symptomatic embolisms and relapses within 6 months after the inclusion in the study will be prospectively registered and compared. CONCLUSIONS: SATIE will investigate whether a two weeks short-course of intravenous antibiotics in patients with IE caused by gram-positive cocci, without signs of persistent infection, is not inferior in safety and efficacy to conventional antibiotic treatment (4-6 weeks). TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04222257 (January 7, 2020). EudraCT 2019-003358-10.

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.

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

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.

Case of cutaneous botryomycosis in an 8-year-old immunocompetent boy with a review of the published work.

Botryomycosis is a rare chronic suppurative granulomatous infection caused by several genera of non-filamentous bacteria. The clinical and histopathological findings are similar to those of mycetoma caused by true fungi or aerobic actinomycetes. Botryomycosis is divided into cutaneous and visceral disease, with the cutaneous form being more common. Histopathology shows granules of etiologic bacteria called "sulfur granules". Botryomycosis occurs more commonly among immunocompromised patients, although some cases have also been reported in immunocompetent patients. We report the case of an 8-year-old immunocompetent boy who visited our hospital with a 4-mm diameter subcutaneous tumor with mild tenderness on his right heel for several months. We surgically removed the tumor with an initial diagnosis of epidermal cyst. Histopathology showed sulfur granules surrounded by an eosinophilic matrix, indicating the Splendore-Hoeppli phenomenon. The granules consisted of Gram-positive cocci, leading to a diagnosis of botryomycosis. The patient was successfully treated by excision and oral trimethoprim/sulfamethoxazole (240 mg b.i.d.) for 2 weeks as adjuvant therapy. No recurrence was noted following treatment. The subcutaneous tumor in this case was smaller than the typical in botryomycosis infections. We reviewed the infection duration and tumor size in reported cases of botryomycosis in immunocompetent patients. Small tumor size may suggest that the case is in an early stage; therefore, it is important to remove and investigate these lesions proactively.

Rapid multiplex detection of the resistance genes mecA, vanA and vanB from Gram-positive cocci-positive blood cultures using a PCR-dipstick technique.

Introduction. Among the causative agents of bloodstream infections (BSIs), methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) are the key causative pathogens. Their rapid detection directly from Gram-positive cocci-positive blood culture specimens will promote timely treatment and help to implement effective infection control measures.Aim. We aim to develop a PCR-dipstick technique for the rapid detection of MRSA and VRE directly from positive blood culture specimens.Methodology. PCR-dipstick is a PCR-based multiplex detection technique where DNA-DNA hybridization is employed, and the results are interpreted with the naked eye. It was designed to target three drug resistance genes: mecA in MRSA and vanA/vanB in VRE from positive blood culture specimens. A total of 120 clinical isolates were used to evaluate the sensitivity and specificity of PCR-dipstick. Then, PCR-dipstick was examined for MRSA and VRE detection directly from positive blood cultures.Results. PCR-dipstick showed 100 % sensitivity and specificity in detecting mecA, vanA and vanB genes directly from bacterial colonies in comparison with multiplex PCR for genomic DNA followed by agarose gel electrophoresis. Further, it could differentially detect multiple resistant genes in pooled bacterial colonies (n=10). Ultimately, PCR-dipstick could detect MRSA and VRE in positive blood cultures in ~3 h.Conclusion. The results of the current study substantiate that PCR-dipstick can be used as an efficient detection system for MRSA and VRE directly from Gram-positive cocci-positive blood cultures. Its affordability and rapidity indicate that PCR-dipstick can be an effective tool for controlling nosocomial pathogens.

Association between baseline abundance of Peptoniphilus, a Gram-positive anaerobic coccus, and wound healing outcomes of DFUs.

Diabetic foot ulcers (DFUs) lead to nearly 100,000 lower limb amputations annually in the United States. DFUs are colonized by complex microbial communities, and infection is one of the most common reasons for diabetes-related hospitalizations and amputations. In this study, we examined how DFU microbiomes respond to initial sharp debridement and offloading and how the initial composition associates with 4 week healing outcomes. We employed 16S rRNA next generation sequencing to perform microbial profiling on 50 samples collected from 10 patients with vascularized neuropathic DFUs. Debrided wound samples were obtained at initial visit and after one week from two DFU locations, wound bed and wound edge. Samples of the foot skin outside of the wounds were also collected for comparison. We showed that DFU wound beds are colonized by a greater number of distinct bacterial phylotypes compared to the wound edge or skin outside the wound. However, no significant microbiome diversity changes occurred at the wound sites after one week of standard care. Finally, increased initial abundance of Gram-positive anaerobic cocci (GPAC), especially Peptoniphilus (p < 0.05; n = 5 subjects), was associated with impaired healing; thus, GPAC's abundance could be a predictor of the wound-healing outcome.

A Patient with Pediatric Septic Arthritis of the Hip Complicated with Osteomyelitis Responds to Clindamycin.

A 5-year-old girl was referred to our institution with complaints of right hip pain and fever (39.0°C); blood tests and magnetic resonance imaging (MRI) were performed. Blood biochemical results revealed a high inflammatory reaction. MRI results revealed inflammation in the hip joint. She was diagnosed with pediatric septic arthritis of the hip, which required arthrotomy and lavage drainage. Treatment with intravenous vancomycin was initiated on the assumption that the causative bacterial species was Staphylococcus aureus. However, Group A Streptococcus pyogenes (GAS) was subsequently isolated from an intraoperative sample, and the antimicrobial agent was switched to aminobenzylpenicillin (ABPC). Clindamycin (CLDM) was added to the treatment regimen 14 days after surgery as MRI indicated the development and spread of osteomyelitis. Three months post-surgery, MRI findings indicated that the osteomyelitis had resolved and antimicrobial therapy was discontinued. To prevent the spread of osteomyelitis, a combination of CLDM and ABPC should be considered at an early stage, particularly in pediatric patients with GAS-induced septic arthritis.

Activity of dalbavancin against gram-positive cocci isolated from skin and soft tissue infections in Poland.

A total of 368 Gram-positive cocci from ABSSI were included in the study. S. aureus and S. pyogenes were susceptible to dalbavancin with MIC50 0.016 mg/L and MIC90 0.032 mg/L for MSSA and MIC50 0.032 mg/L and MIC90 0.047 mg/L for MRSA; MICs for S. pyogenes were ≤0.002-0.008 mg/L; for E. faecalis and E. faecium, ranging 0.016-0.12 mg/L and 0.012-≥32 mg/L, respectively; MICs for VRE were 0.032-0.125 mg/L.

Comparison of two methods skipping cell lysis and protein extraction for identification of bacteria from blood cultures by matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry / Comparación de dos métodos que eluden la lisis celular y la extracción de proteínas para la identificación de bacterias crecidas en hemocultivos mediante espectrometría de masas MALDI-TOF

OBJECTIVE: Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) is widely used for fast identification of bacteria from blood cultures (BC). We compared the performance of two procedures, one including a pre-enrichment step in brain heart infusion and the other a direct method using vacutainer separator gel tubes (DI), for identification of bacteria from blood cultures by MALDI-TOF MS. MATERIAL AND METHODS: We first prepared a training set of 20 simulated bacteremia specimens, including 10 Gram-negative and 10 Gram-positive species. A total of 145 non-consecutive BCs flagged as positive (68 Gram-negative rods, and 77 Gram-positive cocci) were prospectively analyzed (validation set). RESULTS: A total of 82% and 49% of isolates were correctly identified to the species level by the respective methods. CONCLUSION: The pre-enrichment method outperformed the DI method for identification of virtually all bacterial species included in the panels

OBJETIVO: La espectrometría de masas MALDI-TOF se utiliza comúnmente para la identificación rápida de bacterias crecidas en hemocultivos (HC). Hemos comparado el rendimiento de dos procedimientos, uno que incluye un paso previo del enriquecimiento en caldo corazón-cerebro y el otro un método directo que usa tubos vacutainer con gel separador (DI), para la identificación de bacterias a partir de hemocultivos mediante MALDI-TOF MS. MATERIAL Y MÉTODOS: Analizamos prospectivamente un total de 145 HC no consecutivos (68 con crecimiento de bacterias gramnegativas y 77 de cocos grampositivos). RESULTADOS: Un total de 82% y 49% de los aislamientos fueron identificados correctamente a nivel de especie por los dos métodos, respectivamente. CONCLUSIÓN: El rendimiento del método de pre-enriquecimiento en caldo corazón-cerebro fue mejor que el del método DI para la identificación de la práctica totalidad de las especies bacterianas incluidas en el panel de estudio