The interaction between liver cirrhosis, infection by Streptococcus bovis, and colon cancer.

Whether cirrhotic patients with Streptococcus bovis bacteremia have an increased risk of colorectal neoplasm is uncertain. A multicentric retrospective cohort study was conducted investigating associations between S. bovis biotype and species, cirrhosis, and colorectal neoplasm. Out of 779 patients with S. bovis bacteremia, 69 (8.7%) had cirrhosis. No differences were found in the prevalence of colorectal neoplasm between cirrhotic and non-cirrhotic patients undergoing colonoscopy. Among cirrhotic patients, prevalence of colorectal neoplasms was higher in S. bovis biotype I (S. gallolyticus) bacteremia (80%) than in S. bovis biotype II (33.3%; p < 0.007). In conclusion, risk of colorectal neoplasm is high among cirrhotic patients with S. gallolyticus bacteremia.

A simple clinical decision rule may help to rule out severe bacterial infection and spare antibiotics in febrile young children.

AIM: To assess the performance of a new clinical decision rule (CDR) to identify patients at a low risk of invasive bacterial infection (IBI) among febrile children and its theoretical impact on antibiotic use. METHODS: Prospective study including consecutive children <5 years of age who presented in one French paediatric emergency department with fever without source between January and December 2016. With the collected data, we constructed a CDR based on a sequential approach based on age, clinical toxic signs, urinalysis and procalcitonin level. We evaluated its diagnostic performances to identify IBI and its potential impact on antibiotic use. RESULTS: Among the 1061 children (IBI 11/1061, 1.0%), 693 (65.3%) were classified at low or intermediate risk of IBI, with an IBI prevalence of 0%. The sensitivity and specificity of the CDR to predict IBI were 100% and 73.9%. Negative and positive predictive value were 100% and 3.9%, respectively. Using this new CDR, the current antibiotics exposure would theoretically be reduced from 33.6% to 24.1%. CONCLUSION: The promising interest of this clinical decision rule, using simple and accessible biological and clinical tools, needs to be confirm with an external validation study, which will allow its use in clinical practice.

Ruminococcus gnavus bacteremia: Literature review and a case report associated with acute flare of ulcerative colitis in an immunocompromised patient.

We present a case of bacteremia caused by Ruminococcus gnavus in an immunocompromised patient. R. gnavus is a Gram-positive strict anaerobe bacterium that forms chains. The bacteremia has been associated with an acute flare of ulcerative colitis. Anaerobic bacteremia is becoming increasingly frequent in patients with compromised gastrointestinal barrier. The role of the human microbiota and its alterations in the pathogenesis of immune-related diseases is an expanding area of interest. R. gnavus has been identified as a microorganism that may be responsible for the development of these diseases. The contribution of anaerobic bacteria to the pathogenesis of inflammatory bowel disease (IBD) is discussed, and cases reported up until 2023 were reviewed.

[Optimization in the detection of bacteremia: Integrated use of FilmArray (BCID2) and MALDI-TOF]. / Optimización en la detección de bacteriemias. Uso integrado de FilmArray (BCID2) y MALDI-TOF.

The usefulness of the combined use of MALDI-TOF MS from a subculture with 3-5h of incubation and the BCID2 panel (FilmArray) for the identification of microorganisms from positive blood cultures and its importance in the adjustment of antimicrobial therapy was analyzed. Overall identification with BCID2 was 90.4% (142/157) and with Maldi-TOF MS 83.4% (131/157) (p=0.0858); in 23 polymicrobial episodes (47 strains), the BCID2 panel identified 45 (95.7%) and MALDI-TOF MS 24 (51.1%) (p<0.0000). BCID2 detected the presence of the resistance genes mecA/C (n=16), blaKPC (n=8); blaCTX-M (n=17), blaNDM (n=8), blaOXA-48 (n=1), and vanA/B (n=2). The median time to report a result was 2.0h for BCID2 and 4.0h for MALDI-TOF MS (p<0.0000). Of 124 episodes analyzed, the rapid result of BCID2 led to 82.3% (102/124) therapeutic changes.

Bloodstream infection by Rhodococcus corynebacterioides in a pediatric patient diagnosed with high-risk retinoblastoma.

Rhodococcus is a pathogen that is known to cause infections in animals and humans, mainly in cases of immunocompromised patients. A case of a pediatric cancer patient suffering from a bloodstream infection caused by Rhodococcus corynebacterioides was described in this work. Gram positive rods were isolated from blood cultures. The target bacterium was identified using a combination of biochemical tests, the MALDI-TOF mass spectrometry technique, and the analysis of the 16S rRNA sequence. Moreover, an antimicrobial susceptibility test was performed using the E-test. The isolated bacterium was identified as R. corynebacterioides. The 3-year-old patient was successfully treated with vancomycin and meropenem. This is the first published report of R. corynebacterioides in a pediatric patient diagnosed with retinoblastoma that developed a bloodstream infection. R. corynebacterioides should be considered among the opportunistic infectious agents affecting pediatric cancer patients.

[Actinotignum schaalii: Report of two cases of bacteremia in Argentina]. / Actinotignum schaalii: reporte de dos casos de bacteriemias en Argentina.

Actinotignum schaalii is an emerging pathogen in elderly patients with urinary tract pathologies. Two cases of A. schaalii bacteremia are described. Case 1: 79-year-old patient with a history of benign prostatic hyperplasia. He was admitted to the ward for febrile syndrome, abdominal pain, and dysuria. Case 2: 95-year-old patient with prostatic adenomectomy, urethrostomy due to urethral stricture, and benign prostatic hyperplasia. He was admitted due to febrile syndrome, productive cough, bilateral infiltrates with right paracardiac image, and pleural effusion. In both patients, A. schaalii was isolated in blood cultures, identified by MALDITOF-MS mass spectrometry. Only in case 1 was it confirmed that the focus of bacteremia was urinary. It is important to suspect this emerging pathogen in urinary infections with pathological sediment without developing in traditional culture media to ensure adequate empirical treatment. Since most of the isolates show resistance to ciprofloxacin and trimethoprim-sulfamethoxazole.

Susceptibility of Staphylococcus aureus strains to commercial therapeutic phage preparations.

OBJECTIVES: The aim of this study was to determine the susceptibility of Staphylococcus aureus strains to commercial phage preparations. The strains were isolated from clinical patients as well as from nasal mucosa of healthy carriers. BACKGROUND: The elevating number of antibiotic-resistant S. aureus strains present a therapeutic challenge, especially in high-risk patients. One of the promising ways to solve this problem is phage therapy. METHODS: Susceptibility of 111 carrier strains of S. aureus (4 strains were methicillin-resistant; MRSA) and 81 clinical isolates from bloodstream or skin and soft tissue infections (28 were MRSA) to four commercial phage preparations was assessed in vitro by spot assay. The clonality of S. aureus strains was determined by spa typing. RESULTS: Spa typing revealed 97 distinct spa types. A proportion of 73-80 % of the tested S. aureus strains were revealed to have in vitro phage susceptibility, depending on the clonal affiliation of the strains and phage preparation tested. The susceptibility to phage preparations was significantly higher in MRSA strains (p < 0.001). CONCLUSIONS: In vitro results indicate a promising therapeutic potential of the tested commercial anti-staphylococcal phage preparations. They could be applied to a broad spectrum of bacterial clones, and have an excellent activity especially against MRSA strains (Tab. 2, Fig. 2, Ref. 43).

[Clinical and microbiological characteristics of bloodstream infections in adult neutropenic patients]. / Características clínicas y microbiológicas de infecciones del torrente sanguíneo en pacientes adultos neutropénicos.

Bloodstream infections (BI) are relevant in neutropenic patients because they are associated with an increased number of complications and death. The objective was determinate the epidemiologic and microbiologic features of the BI in neutropenic patients with solid neoplasm (SN) and hematologic neoplasm (HN). Retrospective study in two third level hospitals between 2009 and 2016. They were included all the patients older than 18 years-old with active oncologic disease and neutropenia, who had BI. Patients with dermatologic cancer other than melanoma where excluded. A total of 143 BI in neutropenic were observed, of which 80.4% occurred in HN. Around 97.9% of the patients had a high-risk neutropenia without differences between both groups. The most frequent site of BI was primary bacteremia (46.9%) and catheter-associated infection (21%), without significant differences between the two groups. The gram negatives bacilli (GNB) predominated over the gram positive cocci (GPC) and they represented 74.1% of the isolated bacteria, being Escherichia coli the most frequent (32.8%). Among the gram positive cocci, Staphylococcus aureus (28.1%) was the most frequent isolated, followed by coagulase-negative Staphylococci (CNS). There were no differences in microbiological isolates between both groups. With regard to the antimicrobial susceptibility 67.5% of the CNS, 17.6% of the E. coli and 27.6% of the Klebsiella pneumoniae were multiresistant with no differences between both groups. Only 11.1% of S. aureus isolates were methicillin resistant. In conclusion BI of the neutropenic patients where most frequents within patients with HN, GNB were the main microbiological isolates. High mortality was observed in neutropenic patients with BI.

Bacteremia and sepsis by Arcanobacterium haemolyticum in a young immunocompetent patient.

We report the case of a twenty-year-old immunocompetent male patient presenting to the emergency room with pharyngitis and fever. Blood cultures were drawn and Arcanobacterium haemolyticum (rough biotype) was recovered. The presence of the arcanolysin gene was investigated at the molecular level and the upstream region was amplified and sequenced in order to correlate it with the smooth or rough biotype. Although the isolate was susceptible to penicillin, vancomycin and gentamicin, empirical treatments first with amoxicillin/clavulanic acid (1g/12h) and then with ceftriaxone (1g/12h) failed and the infection evolved to sepsis. Finally, treatment with vancomycin (1g/12h) plus piperacillin/tazobactam (4.5g/8h) was effective. Lemierre's syndrome was ruled out. To the best of our knowledge, this is the first case of bacteremia by A. haemolyticum reported in Argentina.

Bacillus cereus bacteremia in a patient with an abdominal stab wound.

Bacillus cereus is a gram positive microorganism commonly involved in gastrointestinal infection but capable of causing severe infections and bacteremia. We describe here a case of bacteremia caused by B. cereus in a previously healthy young woman admitted to the intensive care unit following emergency surgery due to a penetrating abdominal stab wound and subsequent hepatic lesion. She developed fever during admission and cultures were taken. B. cereus was isolated in blood and hepatic fluid collection cultures. Treatment was adjusted according to the isolate, with good clinical results. It is important to highlight the pathogenic potential of this microorganism and not underestimate it as a contaminant when it is isolated from blood samples.

[Helicobacter cinaedi bacteremia: Presentation of the first cases reported in Argentina]. / Bacteriemia por Helicobacter cinaedi: presentación de los primeros casos descritos en Argentina.

Two cases of bacteremia caused by Helicobacter cinaedi are presented. The first case was diagnosed in a 76-year-old male patient, and was secondary to a vascular access device placement; the second case corresponded to a febrile infant of 37 days of life, and was associated with acute gastroenteritis. H. cinaedi is a microorganism difficult to grow in different culture media and also to identify to species level. In both cases, the microscopic observation of blood culture bottles, the use of mass spectrometry and the subsequent sequencing of the hsp60 gene were essential. In the recent literature, H. cinaedi infections are being reported more frequently. In this report we present the first documented cases of bacteremia caused by H. cinaedi in Argentina.

Acute infectious aortitis presenting as pyelonephritis.

A 65-years-old man with poorly controlled type 2 diabetes presented to the emergency department in sepsis with a 2-week history of new-onset fever, abdominal pain and pyuria. A Computed Tomography without contrast ruled out nephrolithiasis and hydronephrosis, but showed infiltration around the infra-renal aorta (5 x 1 cm) and several retroperitoneal lymph nodes. The periaortic infiltration raised suspicion for acute infectious aortitis. Aortic CT angiography confirmed an aortic pseudo-aneurysm in the infra-renal aorta without signs of impending aortic rupture. A Positron Emission Tomography-Computed Tomography confirmed abnormal 18F-FDG uptake adjacent to the right posterolateral aortic wall. The patient underwent abdominal aortic reconstruction with cryopreserved arterial allograft. Infectious aortitis is a rare but lethal cause of sepsis. Males over 50 years old with diabetes mellitus and peripheral vascular atherosclerotic disease are considered at higher risk. The diagnosis should be considered when a septic patient has vascular risk factors, abdominal pain, bacteremia and suggestive imaging. A CT without contrast showing infiltration around the aorta should, in some context, be promptly followed by Aortic CTA to search for acute aortitis among other less urgent differentials. Antibiotic therapy and involvement of vascular surgeons should be initiated in the emergency department.

[Mycoplasma hominis bacteremia. An underestimated etiological agent]. / Bacteriemia por Mycoplasma hominis: un agente etiológico subestimado.

Mycoplasma hominis is a fastidious bacterium, which usually colonizes the lower urogenital tract and may cause systemic infections in neonates and genital infections in adults. It can also be the cause of serious extra-genital infections, mainly in immunosuppressed or predisposed subjects. CASE PRESENTATION: We describe a case of bacteremia caused by M. hominis in a previously healthy woman after uterine curettage due to incomplete abortion. M. hominis could be an underestimated cause of bacteremia in immunocompetent patients. Mycoplasma organisms have fastidious growth requirements, are often difficult to culture on a cell-free medium and have no cell wall. The conventional method for detection may fail. This is the first report of M. hominis isolation from a positive automated blood culture (BD BACTEC, USA).

Streptococcus agalactiae bacteremia in non-pregnant adult patients at two teaching hospitals.

Streptococcus agalactiae or group B streptococcus (GBS) is a frequent pathogen in immunocompromised adults. The aim of this study was to determine the relative frequency, clinical presentation, antimicrobial susceptibility profile, and risk factors associated with GBS bacteremia in non-pregnant adult patients. We conducted a retrospective analysis of blood cultures performed in two hospitals between the years 2009-2013. From 1110 bacteremia episodes, 13 were caused by GBS, all of which were susceptible to ampicillin. GBS bacteremia was more frequent in females and in patients older than 60 years of age. The most frequent comorbidities were chronic kidney disease, cardiac failure and neoplasia. History of appendectomy was detected in 53.8% of the patients, being the most relevant comorbidity for GBS bacteremia in the multivariate analysis (OR 4.13, p=0.012). The main presentations were primary bacteremia and soft tissue infection. GBS bacteremia was infrequent in our institution, and a history of appendectomy might be related to bacteremia occurrence.

Assessment of anaerobic blood cultures in pediatric oncology patients.

INTRODUCTION: The routine use of a single aerobic bottle for blood culture in pediatric patients has become commonplace, as anaerobic bacteria are not frequently involved in clinically significant infections. The aim of this study was to assess the usefulness of routinely performing anaerobic blood cultures in pediatric oncology patients. METHODS: Prospective study was conducted on pediatric (<18 years) patients affected with febrile syndrome after receiving chemotherapy for hematological or solid malignancies. Samples were inoculated into pediatric aerobic and standard anaerobic bottles (BacT/Alert automatic system). Strains were considered clinically significant, or deemed as contaminants, depending on isolation circumstances and clinical criteria. RESULTS: A total of 876 blood cultures from 228 patients were processed during the 21-month study period (January 2014 to September 2015). Baseline diagnosis included 143 solid tumors and 67/18 cases of leukemia/lymphoma. Bacterial growth was detected in 90 (10.2%) blood cultures for 95 different isolates, of which 62 (7.1%)/63 isolates were considered clinically significant. Among the latter, 38 (60.3%) microorganisms grew in both aerobic and anaerobic bottles, 18 (28.6%) only in aerobic bottles, and 7 (11.1%) only in anaerobic bottles. Gram-negative bacilli (33; 52.4%), mainly from the Enterobacteriaceae family, were the most frequently isolated microorganisms. Overall, only 3 out of 90 isolates (3.3%) were strict anaerobes (Propionibacterium acnes), and all of them were deemed contaminants. CONCLUSION: Strict anaerobes did not cause significant infections in febrile pediatric oncology patients, and anaerobic blood culture bottles offered no additional advantages over aerobic media. Our results suggest that routine blood cultures should be solely processed in aerobic media in this group of patients.

Time to positivity of blood cultures in patients with bloodstream infections: A useful prognostic tool.

OBJECTIVE: The time to positivity (TTP) of blood cultures in patients with bloodstream infections (BSIs) has been considered to be a possible prognostic tool for some bacterial species. However, notable differences have been found between sampling designs and statistical methods in published studies to date, which makes it difficult to compare results or to derive reliable conclusions. Our objective was to evaluate the clinical and microbiological implications of TTP among patients with BSI caused by the most common pathogens. METHODS: A total of 361 episodes of BSI were reported for 332 patients. The survival of the entire cohort was measured from the time of blood culture sampling. In order to compare our results with those of previous studies, TTP was divided in three different groups based on log rank (short TTP <12h; medium TTP ≥12h to ≤27h, and long TTP >27h). Cox proportional hazard models were used to calculate crude and adjusted hazard ratios (HR). RESULTS: The Cox proportional hazard model revealed that TTP is an independent predictor of mortality (HR=1.00, p=0.031) in patients with BSIs. A higher mortality was found in the group of patients with the shortest TTP (<12h) (HR=2.100, p=0.047), as well as those with longest TTP (>27h) (HR=3.277, p=0.031). CONCLUSIONS: It seems that TTP may provide a useful prognostic tool associated with a higher risk of mortality, not only in patients with shorter TTP, but also in those with longer TTP.

Identification and antimicrobial susceptibility testing of positive blood culture isolates from briefly incubated solid medium cultures. / Identificación y determinación de sensibilidad a antibióticos de aislados de hemocultivos a partir de subcultivos de corta incubación.

INTRODUCTION: Mass spectrometry Matrix-Assisted Laser Desorption-Ionization Time-of-Flight (MALDI-TOF) helps in the rapid identification of microorganisms causing blood stream infection. Rapid and reliable methods are required to decrease the turnaround time for reporting antimicrobial susceptibility results from blood culture isolates. METHODS: An evaluation was performed on the reliability of a method for antimicrobial susceptibility testing of positive blood culture isolates from briefly incubated solid medium cultures. RESULTS: The agreement between the evaluated and standard methods was 99.3%. The major and minor error rates were 0.4% and 0.3%, respectively, and no very major errors were observed. CONCLUSION: The inoculation of briefly incubated solid medium cultures into antimicrobial susceptibility testing panels is an easy and reliable technique, and helps to decrease the turnaround time for reporting antimicrobial susceptibility results of positive blood cultures.

Evaluation of the usefulness of a quantitative blood culture in the diagnosis of catheter-related bloodstream infection: Comparative analysis of two periods (2002 and 2012).

INTRODUCTION: A retrospective study was conducted to investigate the usefulness of systematic quantitative blood culture (QBC) in the diagnosis of catheter-related bloodstream infection (CRBSI) during two 1-year periods (2002 and 2012). METHODS: The study included all QBC requests sent to the microbiology laboratory for suspected CRBSI in adults (≥18 years) with any type of intravascular catheter (IVC). Based on a ratio of ≥4:1CFU/mL of the same microorganism between IVC blood culture from any lumen and peripheral blood culture, 5 diagnostic groups were defined: confirmed or probable CRBSI, primary BSI, other focus of infection, and colonization. RESULTS: In total, 4521 QBCs were evaluated; 24% positive in 2002 and 16% in 2012 (P<0.0001). There were 243 episodes of suspected CRBSI (101 in 2002 and 142 in 2012). Confirmed CRBSI episodes were higher in 2002 than 2012 (56% vs 34%) (P<0.0001), whereas colonization episodes were lower (18% vs 38%) (P=0.0006). Gram-positive cocci decrease in 2012 relative to 2002 (56% vs 79.7%) (P=0.022). Almost one-third (32%) of confirmed CRBSI would have been missed if blood from all catheter lumens had not been cultured. CONCLUSIONS: QBC is a useful method for diagnosing CRBSI. Blood samples from all catheter lumens must be cultured to avoid missing around one-third of CRBSI diagnoses.

[Economic impact of nosocomial bacteraemia. A comparison of three calculation methods]. / Impacto económico de las bacteriemias nosocomiales. Comparación de tres metodologías de cálculo.

INTRODUCTION: The excess cost associated with nosocomial bacteraemia (NB) is used as a measurement of the impact of these infections. However, some authors have suggested that traditional methods overestimate the incremental cost due to the presence of various types of bias. The aim of this study was to compare three assessment methods of NB incremental cost to correct biases in previous analyses. METHODS: Patients who experienced an episode of NB between 2005 and 2007 were compared with patients grouped within the same All Patient Refined-Diagnosis-Related Group (APR-DRG) without NB. The causative organisms were grouped according to the Gram stain, and whether bacteraemia was caused by a single or multiple microorganisms, or by a fungus. Three assessment methods are compared: stratification by disease; econometric multivariate adjustment using a generalised linear model (GLM); and propensity score matching (PSM) was performed to control for biases in the econometric model. RESULTS: The analysis included 640 admissions with NB and 28,459 without NB. The observed mean cost was €24,515 for admissions with NB and €4,851.6 for controls (without NB). Mean incremental cost was estimated at €14,735 in stratified analysis. Gram positive microorganism had the lowest mean incremental cost, €10,051. In the GLM, mean incremental cost was estimated as €20,922, and adjusting with PSM, the mean incremental cost was €11,916. The three estimates showed important differences between groups of microorganisms. CONCLUSIONS: Using enhanced methodologies improves the adjustment in this type of study and increases the value of the results.

Ability of procalcitonin to predict bacterial meningitis in the emergency department.

INTRODUCTION: The aim of this study was to analyse and compare procalcitonin (PCT) and C-reactive protein (CRP) as tools for detecting bacterial meningitis and predicting bacteraemia. METHODS: Prospective, observational, and descriptive analytical study of 98 consecutive patients aged ≥15 years and diagnosed with acute meningitis in an emergency department between August 2009 and July 2013. RESULTS: We analysed 98 patients with AM (66 males [67%]); mean age was 44±21 years. The diagnosis was bacterial meningitis in 38 patients (20 with bacteraemia); viral meningitis in 33; probable viral meningitis in 15; and presumptively diagnosed partially treated acute meningitis in 12. PCT had the highest area under the ROC curve (AUC) (0.996; 95% CI, 0.987-1; p<0.001). With a cutoff of ≥ 0.74 ng/ml, PCT achieved 94.7% sensitivity, 100% specificity, negative predictive value (NPV) of 93.9%, and positive predictive value (PPV) of 100%. The mean levels for PCT were11.47±7.76 ng/ml in bacterial meningitis vs. 0.10±0.15 ng/ml in viral meningitis (p <0.001). The AUC for CRP was 0.916 and a cutoff of ≥ 90 mg/L achieved 67.5% sensitivity, 86.3% specificity, PPV of 89.2%, and NPV of 90.4%. As a predictor of bacteraemia in bacterial meningitis, only PCT delivered a significant difference (14.7±7.1 ng/mL vs. 4.68±3.54 ng/mL, p<0.001). A cutoff of ≥ 1.1 ng/mL achieved 94.6% sensitivity, 72.4% specificity, NPV of 95.4%, and PPV of 69.2%; the AUC was 0.965 (95% CI, 0.921-1; p<0.001). CONCLUSIONS: PCT has a high diagnostic power for acute meningitis in emergency department patients. PCT outperforms CRP in the detection of bacterial aetiology and is a good predictor of bacteraemia in bacterial meningitis.