Anaerobic Blood Culture Research Articles

Bacterial contamination of saline used for epidural procedures in an obstetric setting: a randomised comparison of two drawing-up techniques

BackgroundThere is little evidence to inform practice regarding the optimum aseptic technique of drawing up saline for epidural insertion. Our regional practice is to draw up saline from a non-sterile packaged plastic ampoule, therefore introducing the risk of bacterial contamination. Usually, the anaesthetist draws up saline directly from the vial held by an assistant using a needle (needle technique). Alternatively, the saline vial is emptied onto a sterile tray by an assistant and then drawn up by the anaesthetist (tray technique). We hypothesised that the latter will lead to an increase in the number of contaminated saline samples as they are exposed to the environment. MethodsIn labour rooms and before epidural catheter insertion, 110 samples of saline 20mL were randomly drawn up using our hospital’s recommended epidural aseptic precautions, using either the needle or the tray technique. Equal amounts of saline were inoculated into aerobic and anaerobic blood culture bottles. ResultsEleven percent of samples in the needle arm and 24% of samples in the tray arm grew commensal micro-organisms including coagulase-negative Staphylococcus, Micrococcus luteus and Streptococcus viridans. A two-sided Fisher’s exact test for categorical unpaired data showed no statistical difference between the two arms of the trial (P=0.13). ConclusionThe difference in the saline contamination rate between the two techniques did not reach statistical significance. As bacterial contamination occurred with both techniques, we recommend using sterile saline pre-packaged in the epidural tray or individually wrapped sterile glass saline ampoules.

Clinical significance of coagulase-negative staphylococci other than S. epidermidis blood stream isolates at a tertiary care hospital.

We retrospectively evaluated blood culture (BC) isolates of coagulase-negative staphylococci other than Staphylococcus epidermidis (NonSe-CoNS) for clinical relevance at a tertiary care hospital in Germany from January 2011 to September 2015. Clinical data were correlated to microbiological results based on medical records. Infection was considered likely if (1) no other infection and (2) two or more isolates of the same species were present and (3) symptoms ameliorated after therapy. Infection was considered possible if a foreign body was present and (1) and (3) were fulfilled. All the other cases were considered contaminations. 313 patients with blood cultures positive for NonSe-CoNS were identified. 61 patients were excluded, either because of missing data or multiple pathogens in the same blood culture. Of the remaining 252 patients, 58 (23%) were classified as possible (n=32) or likely (n=26) infections. S. haemolyticus was the most frequent isolate (infection: n=28), followed by S. hominis (n=13), S. capitis (n=12), and S. lugdunensis (n=3). One patient died from NonSe-CoNS infection. The source of infection in the majority of patients was foreign bodies (n=43), and endocarditis was present in six cases. Staphylococci always considered contaminations were: S. auricularis, S. caprae, S. schleiferi, S. pettenkoferi, S. saccharolyticus, and S. simulans. The growth of NonSe-CoNS in the anaerobic BC bottle only and a time to positivity >36h were associated with contaminations. One out of four NonSe-CoNS isolates was clinically relevant in our cohort, where S. haemolyticus, S. capitis, S. hominis, and S. lugdunensis contributed to 96.6% of all relevant infections.

Coordination of Metabolism and Virulence Factors Expression of Extraintestinal Pathogenic Escherichia coli Purified from Blood Cultures of Patients with Sepsis

One of the trademarks of extraintestinal pathogenic Escherichia coli is adaptation of metabolism and basic physiology to diverse host sites. However, little is known how this common human pathogen adapts to permit survival and growth in blood. We used label-free quantitative proteomics to characterize five E. coli strains purified from clinical blood cultures associated with sepsis and urinary tract infections. Further comparison of proteome profiles of the clinical strains and a reference uropathogenic E. coli strain 536 cultivated in blood culture and on two different solid media distinguished cellular features altered in response to the pathogenically relevant condition. The analysis covered nearly 60% of the strains predicted proteomes, and included quantitative description based on label-free intensity scores for 90% of the detected proteins. Statistical comparison of anaerobic and aerobic blood cultures revealed 32 differentially expressed proteins (1.5% of the shared proteins), mostly associated with acquisition and utilization of metal ions critical for anaerobic or aerobic respiration. Analysis of variance identified significantly altered amounts of 47 proteins shared by the strains (2.7%), including proteins involved in vitamin B6 metabolism and virulence. Although the proteomes derived from blood cultures were fairly similar for the investigated strains, quantitative proteomic comparison to the growth on solid media identified 200 proteins with substantially changed levels (11% of the shared proteins). Blood culture was characterized by up-regulation of anaerobic fermentative metabolism and multiple virulence traits, including cell motility and iron acquisition. In a response to the growth on solid media there were increased levels of proteins functional in aerobic respiration, catabolism of medium-specific carbon sources and protection against oxidative and osmotic stresses. These results demonstrate on the expressed proteome level that expression of extraintestinal virulence factors and overall cellular metabolism closely reflects specific growth conditions. Data are available via ProteomeXchange with identifier PXD002912.

Microbiological Characteristics and Predictive Factors for Mortality in Pleural Infection: A Single-Center Cohort Study in Korea.

BackgroundIdentification and understanding of the pathogens responsible for pleural infection is critical for appropriate antibiotic treatment. This study sought to determine the microbiological characteristics of pleural infection and to identify potential predictive factors associated with mortality.MethodsIn this retrospective study, we analyzed patient data from 421 cases of parapneumonic effusion. A total of 184 microorganisms were isolated from 164 patients, using two culture systems: a standard method and a method using pairs of aerobic and anaerobic blood culture bottles.ResultsThe most frequently isolated microorganisms were streptococci (31.5%), followed by staphylococci (23.4%), gram-negative bacteria (18.5%) and anaerobes (10.3%). Streptococci were the main microorganisms found in standard culture (41.9%) and community-acquired infections (52.2%), and were susceptible to all antimicrobial agents in drug sensitivity testing. Staphylococci were the most frequently isolated pathogens in blood cultures (30.8%) and hospital-acquired infections (38.3%), and were primarily multidrug-resistant (61.8%). In multivariate analysis, the following were significant predictive factors for 30-day mortality among the total population: CURB-65 ≥ 2 (aOR 5.549, 95% CI 2.296–13.407, p<0.001), structural lung disease (aOR 2.708, 95% CI 1.346–5.379, p = 0.004), PSI risk class IV-V (aOR 4.714, 95% CI 1.530–14.524, p = 0.007), no use of intrapleural fibrinolytics (aOR 3.062, 95% CI 1.102–8.511, p = 0.014), hospital-acquired infection (aOR 2.205, 95% CI 1.165–4.172, p = 0.015), age (aOR 0.964, 95% CI 0.935–0.994, p = 0.018), and SOFA score ≥2 (aOR 2.361, 95% CI 1.134–4.916, p = 0.022).ConclusionIn this study, common pathogens causing pleural infection were comparable to previous studies, and consisted of streptococci, staphylococci, and anaerobes. CURB-65 ≥2, structural lung disease, PSI risk class IV-V, no use of intrapleural fibrinolytics, hospital-acquired infection, older age, and SOFA score ≥ 2 are potential predictors of mortality in pleural infection.

The effect of using blood culture bottle of bronchoalveolar larvage fluid in pneumonia

BackgroundPneumonia is a primary cause of morbidity and mortality in infectious disease, and increasing antimicrobial resistance has raised concerns of treatment failure. Therefore, we evaluated the value of a blood culture bottle for bronchoalveolar lavage (BAL) samples on pathogen identification and on treatment modification in patients with pneumonia.MethodsWe conducted a prospective study and enrolled 39 patients who were hospitalized for pneumonia. Enrolled patients underwent BAL; a 10-ml aliquot was transferred to a sterile container for standard quantitative culture, and a 5 ml aliquot was transferred to both an aerobic and an anaerobic blood culture bottle.ResultsMicrobes were detected in all 39 (100 %) specimens and possible pathogens were identified in 34 patients (84.6 %) from BAL blood culture bottles. In contrast, microbes were detected in 10 patients (25.6 %) and possible pathogens were isolated in 8 patients (20.5 %) in BAL fluid using conventional culture methods. Finally, 8 of 39 (20.5 %) patients changed antibiotics according to the BAL blood culture results and pneumonia improved in 6 of these patients.ConclusionsUsing blood culture bottles for BAL sampling in patients with pneumonia is a sensitive method to detect pathogens in order to identify an adequate antibiotic treatment regimen.

Assessment of anaerobic blood cultures in pediatric oncology patients

IntroductionThe 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. MethodsProspective 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. ResultsA 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. ConclusionStrict 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.

Blood cultures in the paediatric emergency department. Guidelines and recommendations on their indications, collection, processing and interpretation

Blood culture (BC) is the gold standard when a bacteraemia is suspected, and is one of the most requested microbiological tests in paediatrics. Some changes have occurred in recent years: the introduction of new vaccines, the increasing number of patients with central vascular catheters, as well as the introduction of continuous monitoring BC systems. These changes have led to the review and update of different factors related to this technique in order to optimise its use. A practice guideline is presented with recommendations on BC, established by the Spanish Society of Paediatric Emergency Care and the Spanish Society for Paediatric Infectious Diseases. After reviewing the available scientific evidence, several recommendations for each of the following aspects are presented: BC indications in the Emergency Department, how to obtain, transport and process cultures, special situations (indications and interpretation of results in immunosuppressed patients and/or central vascular catheter carriers, indications for anaerobic BC), differentiation between bacteraemia and contamination when a BC shows bacterial growth and actions to take with a positive BC in patients with fever of unknown origin.

Gram-negative and -positive bacteria differentiation in blood culture samples by headspace volatile compound analysis.

BackgroundIdentification of microorganisms in positive blood cultures still relies on standard techniques such as Gram staining followed by culturing with definite microorganism identification. Alternatively, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or the analysis of headspace volatile compound (VC) composition produced by cultures can help to differentiate between microorganisms under experimental conditions. This study assessed the efficacy of volatile compound based microorganism differentiation into Gram-negatives and -positives in unselected positive blood culture samples from patients.MethodsHeadspace gas samples of positive blood culture samples were transferred to sterilized, sealed, and evacuated 20 ml glass vials and stored at −30 °C until batch analysis. Headspace gas VC content analysis was carried out via an auto sampler connected to an ion–molecule reaction mass spectrometer (IMR-MS). Measurements covered a mass range from 16 to 135 u including CO2, H2, N2, and O2. Prediction rules for microorganism identification based on VC composition were derived using a training data set and evaluated using a validation data set within a random split validation procedure.ResultsOne-hundred-fifty-two aerobic samples growing 27 Gram-negatives, 106 Gram-positives, and 19 fungi and 130 anaerobic samples growing 37 Gram-negatives, 91 Gram-positives, and two fungi were analysed. In anaerobic samples, ten discriminators were identified by the random forest method allowing for bacteria differentiation into Gram-negative and -positive (error rate: 16.7 % in validation data set). For aerobic samples the error rate was not better than random.ConclusionsIn anaerobic blood culture samples of patients IMR-MS based headspace VC composition analysis facilitates bacteria differentiation into Gram-negative and -positive.Electronic supplementary materialThe online version of this article (doi:10.1186/s40709-016-0040-0) contains supplementary material, which is available to authorized users.

What should be the antibiotic prescription protocol for burn patients admitted in the department of burns, plastic and reconstructive surgery.

This is a prospective study with the aim to determine specific patterns of burn wound bacterial colonisation and antimicrobial resistance profiles. There is a high incidence of infections and septicaemia in post-burn patients, which, in turn, are associated with high morbidity and mortality, a fact that compelled us to undertake this study. The study was conducted over a period 11 months, from 1 August 2014 to 30 June 2015, in 50 burn patients admitted in our burn unit. Wound cultures were taken after 72 hours of admission from all the patients, and then, empirical systemic antibiotics were administered. For wound cultures; 1 cubic cm tissue was taken and placed in aerobic and anaerobic culture vials and transported to the microbiology lab under all aseptic precautions as soon as possible. At the time of fever any time after 72 hours of admission, 16 ml of blood was drawn under all aseptic precautions. Both aerobic and anaerobic blood culture vials were filled with 8 ml of blood each and transported to the microbiology lab. The results of culture and sensitivity reports of 50 patients were recorded. The data obtained was analysed using appropriate statistical analytical tests. The most common organism responsible for bacteraemia is Pseudomonas (43%). Most of the strains of organisms isolated were resistant to commonly used antibiotics in the hospital; Pseudomonas was found 100% resistant to a combination of ampicillin + sulbactum, ceftriaxone and was most often sensitive to imipenem, amikacin and vancomycin. Methicillin-resistant Staphylococcus aureus (MRSA) was also found resistant to commonly used antibiotics like ceftriaxone, ampicillin + sulbactum and ceftazidime + calvulanic acid. Linzolid and vancomycin were effective in 83% and 100% cases, respectively. We conclude that similar institution-specific studies should be conducted, and such studies will be helpful in providing useful guidelines for choosing effective empirical therapy that will have a great impact on the prevention of infection and its complications in burn patients because of bacteraemia.

Unusual Case of Spondylodiscitis due to Listeria monocytogenes.

A 92 year-old man was admitted to the emergency unit at Nantes University hospital for fever and acute low back pain since one week associated with a systemic inflammatory response syndrome and oliguria. His medical history included arterial hypertension, heart failure and arrhythmia, gastric ulcer and hip arthroplasty. He did not recall gastrointestinal symptoms or specific trauma to his skin. On admission, he had a temperature of 38.2°C and normal blood pressure. General examination was normal apart from low back pain and paraspinal muscle spasm. He had no sign of meningoencephalitis. Blood tests showed a total white cell count of 7.47 G.L-1 with normal neutrophil count (82.7%) and lymphopenia (7.6%) and an elevated C-reactive protein level of 190.8 mg.L-1. Three aerobic and anaerobic blood cultures (Bactec FX, Becton, Dickinson, Sparks, MD, USA) were performed on the peripheral site over the course of 24 h. The two first aerobic blood cultures were positive after 22h of incubation and yielded Gram-positive bacilli. The etiological agent of this bacteremia was identified as Listeria monocytogenes only one hour later after the Gram staining thanks to a modified driven hemolysis method using MALDI-TOF mass spectrometry [1]. After 24h of incubation, the bacterial identification was confirmed by using the hemolytic colony on blood agar plate (bioMerieux, Marcy l’Etoile, France). Esculine test was rapidly positive. According to French Listeria National center, multiplex PCR showed that this strain belonged to the serotype-associated group 4b complex (serotypes 4b, 4d, and 4e). Despite recommendations in invasive listeriosis, lumbar puncture (to objective paucisymptomatic meningoencephalitis) was not achieved in this case given the patient’s age and location of infection [2]. Two days after admission, magnetic resonance imaging of the lumbar spine revealed a multifocal spondylodiscitis with global (L4-L5) and focal (L3-L4 and L5-S1) hyper intensity of the discus in T2 and abnormal hypo-intensity of the adjacent plate of the L3–L4 discus on T1 (Fig. 1). Transthoracic echocardiography did not found any evidence for infective endocarditis. Antibiotic therapy with continuous intravenous amoxicillin (200 mg/kg daily) during six days and gentamicin (5 mg/kg in one daily injection) during four days was started. In vitro susceptibility testing was performed using the Ivyspring

First Report of Clostridium lavalense Isolated in Human Blood Cultures.

An 88-year-old man was admitted to the hospital with worsening malaise, fever, and weakness. Anaerobic blood culture bottles revealed the presence of an anaerobic, Gram-positive sporulated bacillus. Empirical antibiotherapy with intravenous piperacillin-tazobactam was initiated. The patient defervesced after four days and was switched to oral amoxicillin on his 6th day of antibiotic therapy and later discharged from the hospital. Four months later, he had recovered. The bacterium was initially identified as Clostridium butyricum using anaerobic manual identification panel. 16S rRNA gene sequence and phylogenetic analysis showed the bacterium to be Clostridium lavalense, a recently described species with no previously published case of isolation in human diagnostic samples so far. This is the first report of Clostridium lavalense isolation from human blood cultures. Further studies are needed in order to elucidate the role of Clostridium lavalense in human disease and its virulence factors.

The Performance of the Four Anaerobic Blood Culture Bottles BacT/ALERT-FN, -FN Plus, BACTEC-Plus and -Lytic in Detection of Anaerobic Bacteria and Identification by Direct MALDI-TOF MS.

Detection and identification of anaerobic bacteria in blood cultures (BC) is a well-recognized challenge in clinical microbiology. We studied 100 clinical anaerobic BC isolates to evaluate the performance of BacT/ALERT-FN, -FN Plus (BioMérieux), BACTEC-Plus and -Lytic (Becton Dickinson BioSciences) BC bottles in detection and time to detection (TTD) of anaerobic bacteria. BACTEC Lytic had higher detection rate (94/100, 94%) than BacT/ALERT FN Plus (80/100, 80%) (p<0.01) in the studied material. There was no significant difference in detection of anaerobic bacteria among the remaining bottle types. The 67 anaerobic bacteria that signalled positive in all four bottle types were analyzed to compare the time to detection (TTD) and isolates were directly identified by MALDI-TOF MS. There was a significant difference in TTD among the four bottle types (p<0.0001). The shortest median TTD was 18 h in BACTEC Lytic followed by BacT/ALERT FN (23.5 h), BACTEC Plus (27 h) and finally BacT/ALERT FN Plus (38 h) bottles. In contrast, MALDI-TOF MS performed similarly in all bottle types with accurate identification in 51/67 (76%) BacT/ALERT FN, 51/67 (76%) BacT/ALERT FN Plus, 53/67 (79%) BACTEC Plus and 50/67 (75%) BACTEC Lytic bottles. In conclusion, BACTEC Lytic bottles have significantly better detection rates and shorter TTD compared to the three other bottle types. The anaerobic BC bottles are equally suitable for direct MALDI-TOF MS for rapid and reliable identification of common anaerobic bacteria. Further clinical studies are warranted to investigate the performance of anaerobic BC bottles in detection of anaerobic bacteria and identification by direct MALDI-TOF MS.

Butyricimonas virosa bacteraemia identified by MALDI-TOF.

We read with interest the recent report by Ulger Toprak et al. [1] reporting the first case of Butyricimonas virosa bacteraemia published earlier this year. Here we describe the case of a 72-year-old man with colon cancer who presented with septic shock after aortic aneurysm surgery, with Butyricimonas virosa recovered from blood cultures. This anaerobic bacteria and related species had been previously described in rat and human faecal material [2], [3] but never before in an infectious context in humans. The authors point out that this Gram-negative anaerobic bacterium produced catalase, was inhibited on Bacteroides bile aesculin agar and was resistant to kanamycin (1 mg), vancomycin (5 μg) and colistin sulfate (10 μg). This phenotypic features were suggestive of a Prevotella spp. However, 16S rRNA sequencing demonstrated a 99% nucleotide identity with B. virosa [1]. Recently we also identified a case of B. virosa bacteraemia in a 81-year-old male veteran who developed a fever 18 days after a Whipple procedure for adenocarcinoma of the duodenum. Two sets of blood samples were drawn for culture. Gram-negative rods were isolated from the anaerobic blood culture bottle of one set during the fifth day of incubation, after masked subculture of a blood culture bottle triggering positive with a negative Gram stain. Consistent with the report of Ulger Toprak et al. [1], our isolate grew anaerobically on Brucella blood agar (Becton Dickinson, Franklin Lakes, NJ, USA), and on Gram stain appeared as a small Gram-negative rod. Our isolate was catalase positive and was resistant to kanamycin (1 mg), vancomycin (5 μg) and colistin sulfate (10 μg). Utilizing RapID Ana testing (bioMerieux, Marcy l’Etoile, France), the isolate was found to be positive for β-galactosidase, N-acetyl-β-glucosaminidase, indole, leucyl glycine and pyroglutamic acid arylamidase, as was the previously reported isolate; however, a conclusive identification could not be made. The isolate was then evaluated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) (MicroFlex LT; Bruker Daltonics, Leipzig, Germany) with and without a formic acid extraction. Vitek MS identified three separate colonies of the bacterium as Butyricimonas virosa (score = 2.531, MALDI Biotyper 3.1). Our patient recovered without antimicrobial treatment. Molecular identification technologies such as 16S rRNA sequencing and MALDI-TOF provide microbiologists with a much richer understanding of clinical anaerobic bacteriology. Without MALDI-TOF, we would not have correctly identified this organism. Proper identification of significant isolates may help to better define the relationships between particular pathogens and clinical syndromes.

Eggerthella lenta bacteraemia in a patient with Caroli disease

Introduction: Eggerthella lenta is an obligate anaerobic, non-spore-forming, Gram-positive rod found as a normal commensal of the human intestinal flora, which is capable of reducing digoxin into several metabolites. Disease caused by this micro-organism is unusual, although more frequent than reported. Case presentation: A 74-year-old man presented to the emergency room and was admitted with a mild acute cholangitis syndrome. One anaerobic blood culture became positive after 5 days of incubation. After an additional 5 days, the usual aerobic subcultures were negative, whereas anaerobically incubated Columbia blood agar presented tiny smooth colonies. The isolate was capable of reducing digoxin and was identified as Eggerthella lenta. Adequate antibiotic treatment with meropenem had been started and the patient recovered fully. Conclusion: We have described a patient with a potentially fatal bacteraemia with E. lenta that may have gone unnoticed. More case reports are necessary, not only to understand the pathogenicity and clinical course of infections by this neglected bacterium, but also to investigate its digoxin degradation and antimicrobial susceptibility variability.

Hemocultivos en urgencias pediátricas. Guía práctica de recomendaciones: indicaciones, técnica de extracción, procesamiento e interpretación

Blood culture (BC) is the gold standard when a bacteraemia is suspected, and is one of the most requested microbiological tests in paediatrics. Some changes have occurred in recent years: the introduction of new vaccines, the increasing number of patients with central vascular catheters, as well as the introduction of continuous monitoring BC systems. These changes have led to the review and update of different factors related to this technique in order to optimise its use. A practice guideline is presented with recommendations on BC, established by the Spanish Society of Paediatric Emergency Care and the Spanish Society for Paediatric Infectious Diseases. After reviewing the available scientific evidence, several recommendations for each of the following aspects are presented: BC indications in the Emergency Department, how to obtain, transport and process cultures, special situations (indications and interpretation of results in immunosuppressed patients and/or central vascular catheter carriers, indications for anaerobic BC), differentiation between bacteraemia and contamination when a BC shows bacterial growth and actions to take with a positive BC in patients with fever of unknown origin

Probiotics and growth in preterm infants: A randomized controlled trial, PREMAPRO study

Recent studies have suggested that the gut microflora has metabolic effects. We aimed to evaluate postnatal growth in preterm infants who received different probiotic supplements, and to assess the safety of probiotic administration. This prospective, randomized, double-blind, controlled trial was performed at three tertiary care neonatal units. Preterm infants were randomly assigned to receive daily supplementation over 4-6 weeks with placebo (group C) or probiotics (group P). Group P comprised three subgroups: P1 received Bifidobacterium lactis, P2 received Bifidobacterium longum, and P3 received B.lactis and B.longum. We assessed postnatal growth during the supplementation period and up to a corrected gestational age (GA) of 41 weeks when body composition was assessed using whole-body dual-energy X-ray absorptiometry. Aerobic and anaerobic blood cultures were performed on suspicion of late-onset sepsis. The study comprised 199 preterm infants with a mean GA of 29.1±1.4 weeks and a mean birth weight of 1173±210g, who received a placebo (group C, n=52) or probiotics (group P, n=147) from the first week of life. At the end of the supplementation period, no statistically significant differences were seen between the groups in relation to the mean body weight (group C=1906±23g, group P=1875±14g, p=0.25), length, or head circumference. The incidence rates of necrotizing enterocolitis and late-onset sepsis were similar in the two groups. At the corrected GA of 41 weeks, there were no differences between the groups with respect to anthropometric measurements or body composition analysis. Preterm infants receiving Bifidobacterium supplements did not exhibit better postnatal growth compared with those who received placebo treatment. No adverse effects were associated with probiotic administration. Registered under ClinicalTrials.gov Identifier no. NCT01379417.

Anaerobic blood culture isolates in a Norwegian university hospital: identification by MALDI-TOF MS vs 16S rRNA sequencing and antimicrobial susceptibility profiles.

We investigated 197 anaerobic isolates recovered from blood cultures in the period 2009-2013. The isolates included were Bacteroides spp., Clostridium spp., Prevotella spp., Fusobacterium spp. and Gram-positive anaerobic cocci (GPAC). Identification results by MALDI-TOF MS were compared to those obtained by 16S rRNA sequencing, and the MICs of benzylpenicillin, clindamycin, piperacillin-tazobactam, meropenem and metronidazole were determined by Etests. The MALDI-TOF MS correctly identified 94.9% of the anaerobes to the genus level, and 86.8% to the species level, with errors mainly among the non-fragilis Bacteroides spp. and GPAC. About 73.3% of the isolates were non-susceptible to penicillin, mainly due to high resistance rates in the Bacteroides spp. (99.2%) and Prevotella spp. (69.2%). About 18.5% of the isolates were clindamycin resistant. Piperacillin-tazobactam had an excellent activity against all anaerobes except the non-fragilis Bacteroides spp., of which 43.8% were non-susceptible. The clinical significance of such a high resistance rate is unclear. Meropenem and metronidazole were the most active antibiotics, with 96.9% and 97.9% of the isolates being susceptible.

Judicious utilization of healthcare resources: reducing unindicated pediatric anaerobic blood cultures in a pediatric hospital.

The decline in anaerobic infections in the past 15 years has resulted in healthcare professionals questioning the need for routine anaerobic blood cultures. In this study, we extracted baseline aerobic and anaerobic blood culture rates over the past 10 years (2001-2010) from our pediatric wards. A questionnaire survey of doctors was conducted to gather their views regarding anaerobic blood cultures. Interventions such as physician education were introduced over 6 months to reduce unindicated anaerobic blood cultures. Furthermore, the rates of blood cultures were tracked over time after intervention. Before intervention, 85% of doctors surveyed routinely ordered anaerobic blood cultures, 90% were unaware of any guidelines for anaerobic blood cultures, and 100% were unaware of the costs. The combination of physician education and restrictive interventions resulted in an 80% reduction in the number of anaerobic blood cultures performed and processed, which translated into savings of USD $2,883 per week, with projected savings of USD $145,560 annually.

Effect of blood volume in standard anaerobic blood culture bottles of the BacT/ALERT 3D system used for the detection of pathogens and time to detection.

BackgroundBlood volume may profoundly affect the isolation of microorganisms in blood cultures. The effect of blood volume in standard anaerobic bottles of the BacT/ALERT 3D system was investigated.MethodsAdult patients who visited the emergency department and referred for blood culture (n = 824) were enrolled from June to September 2013. Two sets of blood cultures were obtained from each patient. One set consisted of 5 mL that was collected in a standard aerobic bottle (SA5), 5 mL that was collected in a standard anaerobic bottle (SN5), and 10 mL that was collected in a standard anaerobic bottle (SN10). The growth of clinically significant pathogens and the time to detection (TTD) were compared between the SN5 and SN10 samples.ResultsIncreasing the volume of blood collected from 5 to 10 mL yielded a 14.7% improvement in the isolation of microorganisms. There was a statistically significant difference in the isolation of pathogens (14 vs. 30, P = 0.023) between the SN5 and SN10 samples. Gram-positive microorganisms were detected earlier in the SN10 samples than the SN5 samples (P = 0.052). The mean TTD of all pathogens was 13.5 h for the SN5 samples and 12.9 h for the SN10 samples (P = 0.099).ConclusionIncreased blood volume in the SN bottle yielded a significantly higher pathogen detection rate. However, there was no difference in the frequency of earlier detection or TTD between the SN5 and SN10 samples.

Microbiological Characteristics according to Transudative and Exudative Effusion in Pleural Fluid Culture

Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, KoreaA total of 1,132 pleural fluid culture results obtained from October 2012 to July 2014 were analyzed to eluci-date the microbiological characteristics according to transudative and exudative pleural fluid. The pleural fluid cultures were performed using aerobic and anae-robic blood culture bottles. The blood and pleural fluid for total protein, lactate dehydrogenase, and glucose measurement were submitted to laboratory at the same time with pleural fluid cultures. The rates for culture positivity, anaerobes isolation, and polymicrobials be-tween transudative and exudative pleural fluid were 5.2% vs. 10.4%, 14.8% vs. 7.8%, and 14.8% vs. 10.9%.