Etiology Of Bloodstream Infections Research Articles

The Etiology of Bloodstream Infections at an Italian Pediatric Tertiary Care Hospital: A 17-Year-Long Series.

Knowledge of epidemiology is essential for guiding correct antibiotic prescription, reducing bacteremia-associated mortality, and implementing targeted infection control programs. However, only a few studies have reported on the epidemiology of bloodstream infections (BSIs) in pediatrics. We performed a retrospective analysis of all BSIs (excluding those caused by common skin contaminants) diagnosed from 2006 to 2022 in patients younger than 18 years who were treated at an Italian pediatric tertiary care hospital. Overall, 2395 BSIs were recorded, including 2207 (92.15%) due to bacteria and 188 (7.85%) due to fungi. The incidence rate (BSIs/10,000 hospital discharges, IR) of bacterial BSIs significantly increased during the study period. In particular, BSIs caused by S. aureus (including MRSA), Enterobacterales (including ESBL and AmpC producers), Enterococcus spp., and P. aeruginosa became more common. The frequency of carbapenem-resistant strains was <1% and stable over time. Conversely, there was a significant reduction in the incidence of BSIs due to S. pneumoniae. The BSIs were stratified by patient age, and S. aureus was the most frequent cause of BSIs in all age groups, while E. coli was the most frequent in the Enterobacterales family. S. agalactiae was the third most frequent cause of neonatal early-onset BSIs. The prevalence of Enterococcus spp. increased in the subgroups from 8 days to 5 years of age, while P. aeruginosa became more prevalent in children over 5 years of age. S. aureus was also the most frequent isolate in both community- and hospital-onset BSIs, followed by E. coli. The prevalence of multidrug-resistant (MDR) pathogens was very low. It was <5% for both Gram-positive (i.e., MRSA and VRE) and Gram-negative (ESBL, AmpC, and carbapenem-resistant) pathogens, and MDR pathogens were almost exclusively detected in hospital-onset BSIs. Fungi accounted for just under 8% of BSIs. C. albicans was the most frequently isolated strain, followed by C. parapsilosis. Notably, the IR of fungemia did not change significantly during the study period, in spite of an increase in the absolute number of events. The continuous monitoring of local epidemiology is essential to identify changes in the IRs of pathogens and antibiotic susceptibility and to guide antibiotic treatments, especially in the phase when antibiograms are not yet available.

Etiology of bloodstream infections among pediatric patients in Bauchi metropolis, north-east Nigeria

Background: The prevalence of bacterial infections in children is increasing by the day, this gives a cause for concern regarding the high rate of bloodstream infection (BSI) and associated mortality in developing countries. Physical signs and symptoms may be useful but have limited specificity which would be addressed with bacteriologic blood culture. This study was aimed at determining the etiologic agents of bacteremia and the prevalence in pediatric patients aged 0-5years. Methods: Two hundred and sixty- two (262) blood samples were analyzed from children aged 0-5years, attending hospitals within Bauchi metropolis with features suggestive of septicemia. Samples were collected under aseptic conditions and automated blood culture was done on BacT/ALERT 3D Biomerieux, Germany. Positive blood culture was sub-cultured on blood agar and MacConkey agar and identified on Vitek2 (bioMѐrieux, France) automated system after gram staining. Changes in pathogen distribution according to age and gender were determined by the chi-square test and statistical significance confirmed if a two-tailed p-value was not more than 0.01. Results: Bacteria was isolated in 119 (45.4) of samples with highest rate among neonates 54(45.3). Staphylococcus aureus 21 (17.6) was the most predominant organism isolated across all age groups with a higher occurrence in patients&lt;1year old. A chi-square test of independence for culture positivity and age/gender at p&lt;.01 was not significant Conclusion: In this study both Gram-positive and Gram-negative bacteria are implicated in pediatric bloodstream infections. Staphylococcus aureus was the most predominant organism followed by members of the Enterobacterales (Enterobacter spp, Klebsiella spp and Escherichia coli).

Bloodstream infections: trends and evolution of incidence and etiology in a 12-year period (2010–2021)

Introduction The epidemiological evolution of bloodstream infections (BSIs) in the last decade is not clearly defined. Our aim was to analyze the changes in the workload in our institution and to describe the evolution of the incidence and etiology of BSIs in a 12-year period, including the COVID-19 pandemic. Methods All blood cultures received in the laboratory of a tertiary general hospital between 2010 and 2021 were analyzed. Bloodstream infection episodes refer to each episode of bacteremia or fungemia in each patient. Incidence rates per 1000 admissions and per 100,000 population were calculated. Results No significant changes in the incidence of BSI episodes/1000 admissions were observed (mean, 31.1), while estimated population-based incidences showed declining trends (mean, 182.8/100,000 inhabitants). There was a slight increase in BSI episodes per 1000 admissions caused by Gram-negatives (mean, 16.6/1000 admissions) and E. coli was the most frequent pathogen (mean, 8.5/1000 admissions). There was no significant rise in episodes caused by ESBL- and carbapenemase-producing E. coli or K. pneumoniae, with a decline in those caused by methicillin-resistant S. aureus. A spike in BSI episodes, fungal BSIs and catheter-related infections was detected in 2020, during the COVID-19 outbreak. Conclusions No clear increase in the incidence of BSI episodes was detected in our center over this period. Gram-negatives are the most frequent etiology, with no clear rise in antimicrobial resistance phenotypes. The COVID-19 pandemic accounted for a small increase in BSI episodes in 2020, probably related to the increase of catheter-related infections.

Antimicrobial use and aetiology of bloodstream infections in critically ill patients during early stages of SARS-CoV-2 pandemic

BackgroundDuring early stages of COVID-19 pandemic, antimicrobials were commonly prescribed.AimTo describe clinical, microbiological and antimicrobial use changes in bloodstream infections (BSI) of ICU patients during the first wave of COVID-19 pandemic compared to pre-COVID-19 era.MethodsObservational cohort study of patients admitted to ICU of Bellvitge University Hospital was conducted during the COVID-19 pandemic (March-June 2020) and before COVID-19 pandemic (March-June 2019). Differences in clinical characteristics, antimicrobial consumption and incidence and aetiology of BSI were measured.FindingsCOVID-19 patients had significantly less comorbidities with obesity the only risk factor that increased in frequency. COVID-19 patients more frequently required invasive supportive care measures, had longer median ICU stay and higher mortality rates. The incidence of BSIs was higher in COVID-19 period (RR 3.2 [95%CI 2.2–4.7]), occurred in patients who showed prolonged median ICU stay (21days) and was associated with high mortality rate (47%). The highest increases in the aetiological agents were observed for AmpC-producing bacteria (RR 11.1 [95%CI 2.6–47.9]) and non-fermenting rods (RR 7.0 [95%CI 1.5–31.4]). The emergence of bacteraemia caused by Gram-negative rods resistant to amoxicillin-clavulanate, which was used as empirical therapy during early stages of the pandemic, led to an escalation towards broader-spectrum antimicrobials such as meropenem and colistin which was also associated with the emergence of resistant isolates.ConclusionsThe epidemiological shift towards resistant phenotypes in critically ill COVID-19 patients was associated with the selective use of antimicrobials. Our study provides evidence of the impact of empirical therapy on the selection of bacteria and their consequences on BSI over the subsequent months.

Bloodstream infections in different stage of reconstitution after first allogeneic hematopoietic stem cell transplantation

Background. Bloodstream infections (BSI) are common after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The objective of study was to analyze pre- and post-engraftment BSI.Materials and methods. From January 2018 till May 2021242 patients after first allo-HSCT were enrolled in the study. Median age was 35 (17–65) years. The majority of transplants were done for acute leukemias (71.9 %) in remission (91.7 %) with reduced-intensity conditioning regimens (71.5 %) and peripheral blood stem cells (74.4 %) as a graft source.Results. Of 242 patients 95 (39.2 %) developed BSI: 79 (83.2 %) developed 1 BSI episode, 16 (16.8 %) – 2 or more. Overall 113 BSI episodes were registered: 94 (82.7 %) were caused by single microorganism, 19 (17.3 %) were polymicrobial. Probability of pre-engraftment BSI was 31.0 %, post-engraftment – 11.8 %. In total 134 microorganisms were identified: 61.2 % – gram-negative and 38.8 % – gram-positive bacteria. Gram-negative BSI rate was significantly higher during post-engraftment compared to pre-engraftment phase (57.7 % vs. 70.3 %; р = 0.008). Major risk factor for pre-engraftment BSI was mismatched unrelated allo-HSCTs (hazard ratio (HR) 2.55; 95 % confidence interval (CI) 1.32–4.91; р = 0.03), for post-engraftment BSI – secondary poor graft function (HR 21.70; 95 % CI 7.95–59.24; р &lt;0.0001) and graft failure (HR 21.55; 95 % CI 6.27–74.08; р &lt;0.0001), and gut graft-versus-host disease (HR 12.90; 95 % CI 5.77–28.80; р &lt;0.0001). Thirty-day survival after each BSI episode was 90.3 % and was significantly lower in patients with post-engraftment BSI compared to pre-engraftment (71.9 % vs. 97.5 %; р &lt;0.0001).Conclusion. Gram-negative bacteria prevailed in the etiology of BSI. The main risk factors for pre-engraftment BSI was allo-HSCT from mismatched unrelated donors, for post-engraftment BSI – secondary poor graft function and graft failure. Post-engraftment BSI is associated with worse prognosis.

Epidemiology and etiology of blood stream infections in a Belgian burn wound center

ABSTRACT Background Infections are a major cause of morbidity in burn patients. We aimed to investigate the epidemiology and antibiotic susceptibility of blood stream infections in order to gain a better understanding of their role and burden in our Burn Wound Center. Methods This retrospective epidemiological investigation analyzed data derived from medical files of patients admitted to our Burn Wound Center having had at least one positive blood culture between 1 January and 31 December 2018. We focused on the prevalence of causative agents in blood stream infections in function of the time after injury and on their drug sensitivity. Results Among the 363 patients admitted to our Burn Wound Center during the study period, 29 had at least one episode of blood stream infection. Gram-negative organisms accounted for 56,36% of the pathogens in blood stream infections, Gram-positives for 38,17%, and yeasts for 5,45%. Pseudomonas aeruginosa was the most common bacterium (20%), followed by Staphylococcus epidermidis (16.36%), Escherichia coli and Klebsiella pneumoniae (9,09% each). A third of the Gram-negative isolates were multidrug resistant. Gram-positive cocci were isolated from blood cultures at a median of 9 days after the injury, earlier than Gram-negative rods (median 15 days). The main sources of blood stream infections were the burn wounds, followed by infected catheters. Conclusions Multidrug resistant bacteria must be considered when selecting empirical antibiotic therapy in septic burn patients. In our center, we need to update our antibiotic guidelines, to review the hospital infection control measures and to introduce routine typing technology.

Trends of Pediatric Bloodstream Infections in Stockholm, Sweden: A 20-year Retrospective Study.

The etiology of bloodstream infections (BSIs) changes over time due to updated immunization programs, new antibiotic-use strategies, changes in patient mix and travel. Continuous surveillance can guide empiric therapy and identify targets for prevention. We conducted a descriptive retrospective analysis among children <18 years of age who were detected with BSI between July 1998 and June 2018 for changes in the incidence, risk factors, and etiology of BSI in a Swedish tertiary hospital (Karolinska University Hospital). We evaluated 2079 episodes of BSI. During the study period, the incidence of BSI in children 0-17 years of age decreased (τ = -0.45, P = 0.016), which was most evident among children 3 months to 2 years of age (τ = -0.59, P = 0.0006) and in early neonatal period (0-7 days; τ = -0.44, P = 0.0069). These were explained by the reduced occurrence of Streptococcus pneumoniae in children 3 months to 2 years of age and Streptococcus agalactiae and Candida spp. in neonates. Staphylococcus aureus was the commonest pathogen, accounting for 31.6% of episodes. The proportion of hospital-acquired infection was higher in patients with underlying risk factors (47.6% vs. 2.6%). The etiology of hospital-acquired infection BSI was more diverse than that of community-acquired infections and was related to underlying risk factors. The crude mortality rate was 5.7%. For children admitted to the neonatal ward, the mortality was 17.6%, but declined (τ = -0.469, P = 0.004) over the study period. There was a decreasing trend of pediatric BSI and mortality over last 20 years, which was associated with pneumococcal immunization and antimicrobial prophylaxis for high-risk patients.

1171. Impact of Catheter Management on the Clinical Outcome in Adult Cancer Patients with Gram-Negative Bacteremia

BackgroundOver the last 2 decades, Gram-negative organisms have been on the rise as an etiology of bloodstream infections (BSI) in cancer patients. Management of the central venous catheter (CVC) in the setting of Gram-negative BSI remains challenging. The aim of our study was to evaluate cancer patients with different types of Gram-negative BSI, in the presence of an indwelling CVC, and assess the impact of line management on the outcome of the BSI.MethodsWe identified all the patients older than 14 years with CVC who had a documented BSI with a Gram-negative organism at M.D Anderson Cancer Center, from May 2017 until May 2018. Patients were divided into three groups. Group 1 (G1) included patients with central-line associated bloodstream infection and no mucosal barrier injury (non-MBI CLABSI) and/or those who met the catheter-related bloodstream infection (CRBSI) criteria; Group 2 (G2) consisted of patients who had a CLABSI with a mucosal barrier injury that did not meet the CRBSI definition; and Group 3 (G3) consisted of patients who had a non-line-related BSI. We assessed catheter management (CVC removed/exchanged or retained) at 2 days after the onset of bacteremia. We then determined the effect of line management on clinical and microbiologic outcomes through various measures.ResultsA total of 300 patients were included with 100 patients in each group. The univariate analyses showed that in G1, CVC removal within 2 days of bacteremia was significantly associated with higher rate of microbiologic eradiation of the bacteremia compared with delayed CVC removal (3 to 5 days) or CVC retention (98% vs. 72% vs. 78% respectively, P = 0.002; P < 0.001), and lower overall mortality rate at 3 months follow-up (3% vs. 22% vs. 17% respectively, P = 0.02; P = 0.01). By multivariate analysis, this association persisted (P = 0.018 and P = 0.016, respectively). CVC removal within 2 days of bacteremia did not affect the outcome of BSI in G2 and G3.ConclusionCVC removal within 48 hours of the onset of Gram-negative bacteremia significantly improved the infectious outcome and the overall mortality in adult cancer patients with definite CRBSI and CLABSI without MBI.Disclosures All authors: No reported disclosures.

Prevalence, etiology, and antibiotic resistance profiles of bacterial bloodstream infections in a tertiary care hospital in Northern India: A 4-year study.

INTRODUCTION:Bloodstream infections (BSIs) can lead to life-threatening sepsis and are globally associated with high morbidity and mortality. Although BSIs require immediate antimicrobial treatment, their prevalence, etiology, and antimicrobial susceptibilities differ from one country to other. There is a dearth of such data from India. Here, we report the 4-year etiologic data on BSI in trauma patients admitted to a tertiary care referral hospital in New Delhi, India.MATERIALS AND METHODS:A retrospective study was conducted at the trauma center between January 2013 and December 2016. The routine microbiological data on bacterial BSI were recorded and determined retrospectively from the laboratory records. Antimicrobial susceptibility profiles were statistically analyzed.RESULTS:A total of 2017 bacterial strains isolated from blood culture samples were included for microbiological analysis. During the study, the median age of the patients varied from 30 to 35 years, with the percentage of females in the study population varying from 17% to 19%. The predominant pathogens were Gram-negative bacteria, with Acinetobacter species, followed by Klebsiella species being the most commonly isolated organisms throughout the 4 years of study. Among Gram-positive isolates, Staphylococcus species were the leading pathogens (11%–15%).CONCLUSIONS:A detailed analysis of prevalence, etiology of BSIs in India and its resistance profile is crucial for appropriate antibiotic use, clinical management, and formulation of antibiotic policies and preventive measures.

Clinical Characteristics of Bloodstream Infections in Pediatric Acute Leukemia: A Single-center Experience with 231 Patients.

Background:Acute leukemia is the most common pediatric hematological malignancy. Bloodstream infections (BSIs) are severe complications in these patients during chemotherapy. This study aimed to explore the clinical presentation and etiology of BSI, as well as the common sites of infection, and to provide a basis for the rational regarding antibiotic use.Methods:We performed a retrospective chart review of all pediatric patients who had acute leukemia accompanied by a BSI in our hospital from December 2011 to September 2015. All patients were selected based on clinical presentation and had to have at least one positive blood culture for inclusion. The basic clinical characteristics, blood culture results, and antimicrobial susceptibilities were analyzed.Results:All 231 patients had a fever; of them, 12 patients continued to have a fever. Twenty-five patients had nonremitting (NR) leukemia, and 206 patients achieved complete remission (CR). Differences in the duration of fever between the NR and CR groups were significant (9.6 ± 7.9 vs. 5.1 ± 3.8 days, P = 0.016). One hundred and eighty patients had agranulocytosis. Differences in fever duration between the agranulocytosis and nonagranulocytosis groups were significant (6.2 ± 5.1 vs. 4.1 ± 2.6 days, P = 0.001). The other sites of infection in these 231 patients were the lung, mouth, digestive tract, and rectum. Blood culture comprised 2635 samples. There were 619 samples, which were positive. Of the 619 positive blood culture samples, 59.9% had Gram-negative bacteria, 39.3% had Gram-positive bacteria, and 0.8% had fungus. The primary pathogens were Pseudomonas aeruginosa, Enterobactercloacae, Escherichia coli, and Klebsiella pneumoniae. Of these 231 patients, 217 patients were cured. The effective treatment ratio was 94%.Conclusions:Gram-negative bacteria were the main pathogenic bacteria in patients with acute leukemia in our center. NR primary illness, agranulocytosis, and drug-resistant pathogenic bacteria were all risk factors for poor prognosis.

Epidemiology and prognosis of patients with bloodstream infection in 10 hospitals in Colombia

Knowing the local epidemiology and etiology of bloodstream infections allows tailoring the empirical initial antimicrobial therapy to obtain a better outcome for these episodes. To describe the epidemiological and microbiological aspects as well as the factors associated with mortality in patients with bloodstream infection in Colombian hospitals. Sub-analysis of a prospective cohort study of 375 consecutive patients with bloodstream infection in 10 hospitals in Colombia, admitted between September first 2007 and Febrnary 29, 2008. The most frequently isolated bacteria were Gram-negative bacilli in 54% of patients, followed by Gram-positive cocci in 38.4%. The source of infection was known in 67%, unknown in 24% and associated with intravascular catheter in 9%. The most frequently isolated bacteria were Escherichia coli (46%), coagulase-negative Staphylococci (16%), Klebsiella pneumoniae (8.9%) and Staphylococcus aureus (7.8%). Staphylococcus aureus was methicillin sensitive in 82% of patients (46/56). Overall 28-day mortality was 25% and their independent associated factors were age, SOFA score and APACHE II score. In our study the most frequently isolated bacteria in bloodstream infections were Gram-negative bacilli, contrasting those reported in developed countries. The overall mortality rate was high and the factors associated with mortality were age and severity scores.

Etiology of bloodstream infection and antibiotic susceptibility pattern of the isolates

Background: Bloodstream infection (BSI) is a signifi cant cause of morbidity and mortality. In Nepal, very few studies on BSIs have restricted the understanding of their cause, prevention and treatment. This cross-sectional study was conducted to isolate BSIs causing pathogens and determine their antibiotic susceptibility pattern in patients visiting Kathmandu ModelHospital during December 2012 to May 2013.Materials and Methods: Standard laboratory procedure was used to screen, isolate and identify the bacteria from 1,205 patients. The antibiotic susceptibility pattern (AST) was analyzed by modifi ed Kirby Bauer technique and data were analyzed using SPSS version-16.Results: Out of 1,205 blood samples, 186 (15.4 %) were culture positive. The most common bacteria isolated were: Salmonella spp., Escherichiacoli, Klebsiella pneumoniae and CoNS. Gram-negative bacteria were the predominant causes of BSIs. Salmonella Typhi was isolated in 71 % cases of bloodstream infection followed by Salmonella Paratyphi A in 16 %, Escherichia coli in 5.3 % and Klebsiella pneumonia in 0.5 %. The gram-positive organism responsible for causing BSI was coagulase-negative staphylococcus in 7 % cases. There was no significant association between bacteremia and gender of the patients. During ASTs, Gram-negative bacteria were sensitive to Chloramphenicol with only 0.5 % resistivity. Salmonella Typhi (85.6 % of isolates) showed resistance to Nalidixic acid. Gram-positive bacteria showed 100 % sensitivity towards Chloramphenicol and Gentamicin and were least sensitive to Amoxicillin.Conclusion: Salmonella spp., was major cause of BSIs. Increase in antibiotic resistivity for BSI causing pathogens has necessitated continuous monitoring of the susceptibility of organisms towards antibiotics.Asian Journal of Medical Sciences Vol.7(2) 2015 71-75

The aetiology of paediatric bloodstream infections changes after pneumococcal vaccination and group B streptococcus prophylaxis.

This study explored the incidence and aetiology of bloodstream infections after patients received the pneumococcal conjugate vaccination and a risk-based intrapartum antibiotic prophylaxis against early onset sepsis caused by group B streptococcus. We also monitored clinically relevant antimicrobial resistance. We studied 3986 positive blood cultures from children up to 17years of age at a paediatric hospital in Stockholm, Sweden, using data from medical records before and after the initiatives, to reduce early onset sepsis, were introduced in 2007 and 2008. Bloodstream infections caused by Streptococcus pneumoniae declined by 42% overall (5.6 to 3.2/100000) and by 62% in previously healthy children under 36months of age (24.2 to 9.2/100000). Early onset sepsis caused by group B streptococcus declined by 60% (0.5 to 0.2/1000 live born children). Bacterial meningitis caused by these bacteria decreased by 70%. Staphylococcus aureus and various Gram-negative bacteria became the dominant pathogens, in both previously healthy children and those with underlying disease. Overall, antimicrobial resistance remained low between the two 5-year study periods. Pneumococcal conjugate vaccination and risk-based intrapartum antibiotic prophylaxis against group B streptococcus effectively decreased the incidence of bloodstream infections. Empirical antibiotic therapy should target Staphylococcus aureus inboth community and hospital-acquired invasive bacterial infections.

Differential diagnosis of bacterial from candidal bloodstream infections in ICU patients: the role of procalcitonin

Early differentiation of bacterial from candidal bloodstream infections (BSIs) in the presence of sepsis or septic shock is crucial because of the need for appropriate treatment initiation. Clinical data, although limited, suggest a role for procalcitonin (PCT) [1-3]. The aim of this study was to investigate a possible association between the etiology of BSIs and the serum PCT levels.

Epidemiology of bloodstream infections in patients with acute myeloid leukemia undergoing levofloxacin prophylaxis.

BackgroundInfections are a common cause of morbidity and mortality in patients with acute myeloid leukemia (AML). The evidence for efficacy of antibiotic prophylaxis in reducing the mortality rates and the incidence of bacterial infections was also reported by a systematic review published by Cochrane in 2012. The objective of our study was to report the incidence and the etiology of bloodstream infections in patients with AML undergoing levofloxacin prophylaxis during neutropenic episodes.MethodsThis was a retrospective study of patients with diagnosis of AML during 2001–2007.ResultsA total of 81 patients were included in the study. Two hundred and ninetyone neutropenic episodes were studied, of which 181 were febrile. Bacteria isolated from blood cultures were mostly Gram-positives during the induction (80%) and Gram-negatives during the consolidation (72.4%) phases of chemotherapy. Resistance to ciprofloxacin was found in 78.9% of isolated E. coli and it was higher during consolidation and higher than the hospital rate. The production of extended spectrum betalactamases (ESBL) in E. coli strains was reported in 12.1%, below the reported hospital rate during the study period.ConclusionsRegular microbiology surveillance is needed to better understand the impact of levofloxacin prophylaxis in neutropenic patients. Our study shows that Gram-positive bacteria are predominant during the induction phase of chemotherapy and Gram-negatives during the consolidation. The rate of fluoroquinolone resistance in the latter setting, even higher than the hospital rate, may suggest to reconsider levofloxacin prophylaxis.

Risk factors for multidrug-resistant bacteremia in hospitalized cancer patients with febrile neutropenia: A cohort study

We conducted a prospective cohort study in a single tertiary hospital with the aim of assessing predictors of multidrug-resistant bacteremia in 307 cases of febrile neutropenia in adult patients with cancer. On multivariate analysis using stepwise logistic regression, age (P = .009), duration of neutropenia (P = .022), and presence of an indwelling central venous catheter (P = .022) were associated with bloodstream infection by multidrug-resistant bacteria.

Current concepts in the diagnosis of blood stream infections. Are novel molecular methods useful in clinical practice?

The decision on the right empirical treatment in bacteremia places particular demands on the clinician. As long as no microbiological diagnosis can be immediately drawn, the clinical diagnosis together with knowledge of local antimicrobial resistance must determine the antimicrobial choice. The use of several amplification, hybridization, and mass spectrometry methods has been studied in patient cohorts in comparison with blood culture-based conventional techniques. However, no clinical outcome trials have been conducted in which the use of these novel methods would guide antimicrobial therapy. Local differences in bacterial antimicrobial resistance cause differences in the regional need for molecular methods for the early detection of resistance mechanisms. The implementation of novel methods in clinical use requires active discussion between laboratory experts and clinicians. Providing rapid susceptibility results using conventional methods can lead to timely changes to appropriate antimicrobial therapy and the costs are lower than with the molecular methods. Gram-stain information in combination with clinical data is an underestimated, underused, rapid, and economical means of assessing the etiology of blood stream infection.

Bacterial Isolates from Blood Samples of Patients in University of Benin Teaching Hospital Benin City, Edo State, Nigeria.

The presence of bacteria in the blood stream results in a condition known as bacteremia. This condition is associated with pyrexia of unknown origin (PUO). The study seeks to determine the bacterial etiology of bloodstream infections and their susceptibility profile in a tertiary healthcare institution. The design was prospective and crosssectional. Specimens were obtained from patients in no particular selection order except that they were consecutively obtained. The study was carried out in a tertiary healthcare institution which is equipped with a standard microbiology laboratory. Patients seen at the various facilities in the hospital were used for the study. They numbered one thousand, six hundred and seventy (1,670) patients. This was during the period October 2008 to September 2009. The patient population was 1,500 (89.2%) infants while adults were 170 (10.8%). 1ml of venous blood was aseptically inoculated into two blood culture bottles, brain heart infusion broth and thioglycollate broth while giving great attention to sterile process. They were incubated overnight at 37 C and were examined daily for growth. Growth is usually characterized by gas bubbles or turbidity. If there was indication of growth either in the brain-heart infusion broth or the thioglycollate broth or both; gram staining and microscopy were prepared and read. The thioglychollate broth was sub cultured onto blood agar plate for anaerobic incubation, while the brain heart infusion broth was sub cultured onto chocolate, blood agar and McConkey agar for aerobic incubation. The anaerobic incubation was done by putting the culture plates into an anaerobic jar and filling it with hydrogen gas. This was incubated at 37 C overnight. The organisms isolated were identified to species level using the protocol of Cowan and Steel. The antibiotic susceptibility spectrum of the isolates was determined using the agar diffusion method of Bauer and Kirby. Eleven bacterial species were isolated in the study and they varied widely in their antibiotic susceptibilities. Ofloxacin exhibited the highest antimicrobial activity. Staphylococcus aureus was 56.3% susceptible to oxacillin. The study isolated the common bacteria involved in bacteremia and determined their susceptibility profile, and also suggested some control measures. Keywords: Bacteremia; Pyrexia of unknown origin; antibiotic susceptibilities,

Epidemiology, Risk Factors and Outcome of 282 Bloodstream Infections among Hematological Patients: Results of a 50 Months Prospective Surveillance Study

Background. Bloodstream infections (BSI) represent a frequent and potentially life-threatening complication among hematological patients (pts).Aims, Patients and Methods. To evaluate the recent epidemiology, emerging resistant strains, risk factors and outcome of BSI among hematological pts, we prospectively analyzed all febrile/infectious episodes occurring among hematological pts admitted at our Institution during 50 months of observation (April 04–May 08). BSI were correlated with type and status of disease, neutropenia (<0.5 × 10^9/L), fluoroquinolones (Fq) prophylaxis, presence of central venous catheter (CVC) and outcome. Throughout the entire period, levofloxacin 500 mg/d was given to pts with an expected neutropenia ≥7 days and beta-lactam + aminoglycoside ± vancomycin was the regimen adopted for empiric treatment of febrile neutropenia. To better evaluate epidemiological changes, we compared the first period of observation with the second (25 months each).Results. During the entire period, 425 microbiologically documented infections (MDI) were detected among 2682 admissions. BSI represented 66.5% of MDI (282/425) and were more frequent as a cause of MDI in pts with acute leukemia (AL) (p=0.0007), controlled disease (p=0.0001), neutropenia (p=0.0001) and CVC (p=0.0001). Among pts with CVC, CVC-related bacteremias were 21.7%. Gram-positive (G+) bacteria were responsible for BSI in 112 cases (39.7%), Gram-negative (G−) in 169 (59.9%) and fungi (all Candida spp) in 7 (2.5%). In 6 cases a mixed (G+/G−) BSI was detected. Among G+ BSI, staphylococci were detected in 60 (53.6%) cases (15 S. aureus and 45 Coagulase-negative, CoNS), enterococci in 24 cases (21.4%), and viridans streptococci in 19 cases (17%), 14 of which (73.7%) during the second period of observation. E. coli was responsible for 55.6% of G− BSI (94/169) and showed Fq resistance in 80.9% of cases. Pseudomonas spp BSI were observed in 43 cases (25.4% of all G− BSI), 69.8% of which in the second period. Nineteen multi-resistant (MR) strains (6 vancomicinresistant enterococci and 13 MR Pseudomonas) were recorded; all MR Pseudomonas were observed in the second period. The risk of enterococcal BSI was borderline higher in pts with acute leukemia (p=0.052), whereas pts with other haematological malignancies where at higher risk of S. aureus BSI (p=0.0066). Pts with controlled disease had a significantly higher risk of E. coli BSI (p=0.04), those with uncontrolled disease of S. aureus and enterococcal BSI (p=0.0023 and 0.03 respectively). In neutropenic pts the etiology of BSI was more likely represented by E. coli (p=0.0091), whereas in non neutropenic pts by S. aureus (0.0043). Pts receiving Fq prophylaxis developed more likely BSI caused by E. coli (p=0.0006) compared to pts out of prophylaxis, who were at risk for S. aureus BSI (p=0.011). Pts with CVC were at risk for CoNS BSI (p=0.059), whereas pts without CVC for enterococcal BSI (p=0.0107). Death was observed in 24/282 BSI (8.5%) (3 fungi, 5 G+, 14 G−, 2 G+/G−). Active disease (p<0.0001) and BSI due to enterococci (p=0.04), Pseudomonas spp (p=0.001), fungi (p=0.015) and MR strains (p<0.0001) correlated with a poor outcome.Conclusions. BSI represented the most frequent type of infection among hematological pts. G− BSI were more frequent than G+. Specific microorganisms were characteristically responsible for BSI in different subgroups of pts, e.g. Fq-resistant E. coli in patients with posttreatment neutropenia, no active disease, and previous Fq prophylaxis. MR enterococci and Pseudomonas spp were observed in 6.7% of BSI; MR Pseudomonas were emerging in the second part of the study. Together with fungi and active underlying disease, MR strains were responsible for an increased risk of death in pts with BSI.

Bloodstream Infections

Information available on bloodstream infection (BSI) is usually restricted to short periods of time, certain clinical backgrounds, or specific pathogens, or is just outdated. We conducted the current prospective study of patients with BSI in a 1750-bed teaching hospital to evaluate workload trends and the incidence and etiology of BSI in a general hospital during the last 22 years, including the acquired immunodeficiency syndrome (AIDS) era. The main outcome measures were laboratory workload, trends in incidence per 1000 admissions and per 100,000 population of different microorganisms, and the impact of the human immunodeficiency virus (HIV) epidemic in the period 1985-2006.From 1985 to 2006 we had 27,419 episodes of significant BSI (22,626 patients). BSI incidence evolved from 16.0 episodes to 31.2/1000 admissions showing an annual increase of 0.83 episodes/1000 admissions (95% confidence interval, 0.61-1.05; p < 0.0001). The evolution of the incidence per 1000 admissions and per 100,000 population of different groups of microorganisms was as follows: Gram positives 8.2 to 15.7/1000 admissions and 66.8 to 138.3/100,000 population; Gram negatives 7.8 to 16.2/1000 admissions and 63.5 to 141.9/100,000 population; anaerobes 0.5 to 1.3/1000 admissions and 4.1 to 11.7/100,000 population; and fungi 0.2 to 1.5/1000 admissions and 1.7 to 12.5/100,000 population. All those differences were statistically significant. We observed the emergence of multiresistant Gram-positive and Gram-negative microorganisms. At least 2484 episodes of BSI (9.1%) occurred in 1822 patients infected with HIV. The incidence of BSI in HIV-infected patients increased from 1985 and reached a peak in 1995 (17.6% of BSI). Since 1995, the decrease was continuous, and in 2006 only 3.9% of all BSI episodes occurred in HIV-positive patients in our institution. We conclude that the BSI workload has increased in modern microbiology laboratories. Gram-positive pathogens have overtaken other etiologic agents of BSI. Our observation shows the remarkable escalation of some resistant pathogens, and the rise and relative fall of BSI in patients with HIV.