Evaluation of the Neonatal Sequential Organ Failure Assessment and Mortality Risk in Preterm Infants With Late-Onset Infection

IMPORTANCE

Infection in neonates remains a substantial problem. Advances for this population are hindered by the absence of a consensus definition for sepsis. In adults, the Sequential Organ Failure Assessment (SOFA) operationalizes mortality risk with infection and defines sepsis. The generalizability of the neonatal SOFA (nSOFA) for neonatal late-onset infection-related mortality remains unknown.

OBJECTIVE

To determine the generalizability of the nSOFA for neonatal late-onset infection-related mortality across multiple sites.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter retrospective cohort study was conducted at 7 academic neonatal intensive care units between January 1, 2010, and December 31, 2019. Participants included 653 preterm (<33 weeks) very low-birth-weight infants.

EXPOSURES

Late-onset (>72 hours of life) infection including bacteremia, fungemia, or surgical peritonitis.

MAIN OUTCOMES AND MEASURES

The primary outcome was late-onset infection episode mortality. The nSOFA scores from survivors and nonsurvivors with confirmed late-onset infection were compared at 9 time points (T) preceding and following event onset.

RESULTS

In the 653 infants who met inclusion criteria, median gestational age was 25.5 weeks (interquartile range, 24-27 weeks) and median birth weight was 780 g (interquartile range, 638-960 g). A total of 366 infants (56%) were male. Late-onset infection episode mortality occurred in 97 infants (15%). Area under the receiver operating characteristic curves for mortality in the total cohort ranged across study centers from 0.71 to 0.95 (T0 hours), 0.77 to 0.96 (T6 hours), and 0.78 to 0.96 (T12 hours), with utility noted at all centers and in aggregate. Using the maximum nSOFA score at T0 or T6, the area under the receiver operating characteristic curve for mortality was 0.88 (95% CI, 0.84-0.91). Analyses stratified by sex or Gram-stain identification of pathogen class or restricted to infants born at less than 25 weeks' completed gestation did not reduce the association of the nSOFA score with infection-related mortality.

CONCLUSIONS AND RELEVANCE

The nSOFA score was associated with late-onset infection mortality in preterm infants at the time of evaluation both in aggregate and in each center. These findings suggest that the nSOFA may serve as the foundation for a consensus definition of sepsis in this population.

Staphylococcus aureus Bacteremia: Contemporary Management

Staphylococcus aureus bacteremia (SAB) is a serious cause of bloodstream infection associated with significant morbidity and mortality. Complications include deep-seated foci of infection including infective endocarditis, device-associated infection, osteoarticular metastases, pleuropulmonary involvement, and recurrent infection. With the 30-day all-cause mortality being around 20%, a collaborative effort of early Infectious Diseases (ID) consultation and Antimicrobial Stewardship Program (ASP) involvement will show improved SAB outcomes and therapy optimization.1.

The Inflammatory and Hemostatic Response in Sepsis and Meningococcemia

Meningococcemia is notorious for evasion of the host immune system and its rapid progression to fulminant disease, and serves as a unique model for pediatric sepsis. Illness severity is determined by complex interplays among host, pathogen, and environment. The inflammatory host response, including proinflammatory and anti-inflammatory responses in innate and adaptive immunity, skews toward a proinflammatory state. This leads to endothelial dysfunction and activation of the hemostatic response, which may lead to disseminated intravascular coagulation. This article reviews the pathogenesis of sepsis, in particular the inflammatory and hemostatic response in meningococcal sepsis.

Risk factors associated with bacteremia correlated with mortality in patients with acute bacterial skin and skin structure infection

Acute bacterial skin and skin structure infections (ABSSSI) is a common cause of acute admissions worldwide, but the disease is not well understood epidemiologically with respect to factors that determine positive blood cultures or patient mortality. To understand the utility of blood cultures and the association between bacteremia and mortality in patients with ABSSSI, we conducted a retrospective study to investigate factors associated with positive blood cultures and mortality in patients with ABSSSI. A retrospective cohort study of hospitalized adult patients with ABSSSI was conducted in a tertiary hospital in Taiwan between March 2015 and December 2016. A total of 1322 hospitalized patients with ABSSSI are included. The overall mortality rate is 2.1% (28/1322), and 122 patients had positive blood culture results. Comorbidities that are significant risk factors for a positive blood culture include diabetes mellitus and chronic kidney disease. Significant risk factors evident in laboratory evaluations include high C-reactive protein (CRP) level (> 20 mg/dL), hyperglycemia, and hypoalbuminemia. Bacteremia is also a significant factor associated with mortality. A blood culture should be considered for patients with ABSSSI with diabetes mellitus or chronic kidney disease or those exhibiting abnormal CRP, glucose, or albumin levels because of the positive correlation between bacteremia and mortality.

Incidence and clinical features of patients with peritoneal dialysis peritonitis complicated by bacteremia

The standard treatment of peritoneal dialysis peritonitis (PD peritonitis) is intraperitoneal antibiotic therapy. In patients with PD peritonitis complicated by bacteremia, intraperitoneal antibiotics combined with elective removal of the infected intraperitoneal catheter may be inadequate.We collected data of all patients with PD peritonitis admitted to Chi-Mei Medical Center during a 4-year period. We reviewed the medical records of the study cohort and collected their in-hospital details. Patients with positive blood culture results were assigned to the bacteremia group, whereas those with negative blood culture results were assigned to the peritonitis-only group.We discovered that 11.0% of patients with PD peritonitis had bacteremia complications, and immunocompromised comorbidities were more common in the bacteremia group than in the peritonitis-only group (66.7% vs 37.2%, P = .022). Additionally, the bacteremia group exhibited higher temperatures, greater respiratory rates, and lower serum sodium levels than the peritonitis-only group (temperature, 37.7 vs 37.2 °C, P = .014; respiratory rate, 19.1 vs 17.9 rate/min, P = .008; serum sodium level, 130.3 vs 132.7 mEq/L, P = .031). No mortality was found in patients with PD peritonitis complicated by bacteremia after intravenous and intraperitoneal antibiotic therapy.More than 1 in 10 patients with PD peritonitis was complicated by bacteremia, which resulted in extensive systemic derangements. Patients with immunocompromised comorbidities carried a higher risk of developing bacteremia, resulting in prolonged hospital stays. Combination of intraperitoneal and intravenous antibiotics therapies achieved fair prognoses in patients with PD peritonitis complicated by bacteremia.

Rheumatological presentation of Bartonella koehlerae and Bartonella henselae bacteremias: A case report

INTRODUCTION

Systemic Bartonella spp. infections are being increasingly reported in association with complex medical presentations. Individuals with frequent arthropod exposures or animal contact appear to be at risk for acquiring long standing infections with Bartonella spp.

CASE REPORT

This case report describes infections with Bartonella koehlerae and Bartonella henselae in a female veterinarian whose symptoms were predominantly rheumatologic in nature. Infection was confirmed by serology, polymerase chain reaction (PCR), enrichment blood culture, and DNA sequencing of amplified B koehlerae and B henselae DNA. Long-term medical management with antibiotics was required to achieve elimination of these infections and was accompanied by resolution of the patient's symptoms. Interestingly, the patient experienced substantial improvement in the acquired joint hypermobility mimicking Ehlers-Danlos Syndrome (EDS) type III.

CONCLUSION

To facilitate early and directed medical interventions, systemic bartonellosis should potentially be considered as a differential diagnosis in patients with incalcitrant rheumatological symptoms and frequent arthropod exposures or extensive animal contact.

The clinical impact of bacteremia on outcomes in elderly patients with pyelonephritis or urinary sepsis: A prospective multicenter study

Background

Bacteremia is common in severe urinary infections, but its influence on the outcomes is not well established. The aim of this study was to assess the association of bacteremia with outcomes in elderly patients admitted to hospital with pyelonephritis or urinary sepsis.

Methods

This prospective muticenter observational study was conducted at 5 Spanish hospitals. All patients aged >65 years with pyelonephritis or urinary sepsis admitted to the departments of internal medicine and with urine and blood cultures obtained at admission to hospital were eligible. Transfer to ICU, length of hospital stay, hospital mortality and all cause 30-day mortality in bacteremic and non-bacteremic groups were compared. Risk factors for all cause 30-day mortality was also estimated.

Results

Of the 424 patients included in the study 181 (42.7%) had bacteremia. Neither transfer to ICU (4.4% vs. 2.9%, p = 0.400), nor length of hospital stay (9.7±4.6 days vs. 9.0±7.3 days, p = 0.252), nor hospital mortality (3.3% vs. 6.2%, p = 0.187), nor all cause 30-day mortality (9.4% vs. 13.2%, p = 0.223) were different between bacteremic and non-bacteremic groups. By multivariate analysis, risk factors for all cause 30-day mortality were age (OR 1.05, 95% CI 1.00–1.10), McCabe index ≥2 (OR 10.47, 95% CI 2.96–37.04) and septic shock (OR 8.56, 95% CI 2.86–25.61); whereas, bacteremia was inversely associated with all cause 30-day mortality (OR 0.33, 95% CI 0.15–0.71).

Conclusions

In this cohort, bacteremia was not associated with a worse prognosis in elderly patients with pyelonephritis or urinary sepsis.

Physiopathological approach to infective endocarditis in chronic hemodialysis patients: left heart versus right heart involvement

Infectious endocarditis (IE), a complication that is both cardiac and infectious, occurs frequently and is associated with a heavy burden of morbidity and mortality in chronic hemodialysis patients (CHD). About 2-6% of chronic hemodialysis patients develop IE and the incidence is 50-60 times higher among CHD patients than in the general population. The left heart is the most frequent location of IE in CHD and the different published series report a prevalence of left valve involvement varying from 80% to 100%. Valvular and perivalvular abnormalities, alteration of the immune system, and bacteremia associated with repeated manipulation of the vascular access, particularly central venous catheters, comprise the main factors explaining the left heart IE in CHD patients. While left-sided IE develops in altered valves in a high-pressure system, right-sided IE on the contrary, generally develops in healthy valves in a low-pressure system. Right-sided IE is rare, with its incidence varying from 0% to 26% depending on the study, and the tricuspid valve is the main location. Might the massive influx of pathogenic and virulent germs via the central venous catheter to the right heart, with the tricuspid being the first contact valve, have a role in the physiopathology of IE in CHD, thus facilitating bacterial adhesion? While the physiopathology of left-sided IE entails multiple and convincing mechanisms, it is not the case for right-sided IE, for which the physiopathological mechanism is only partially understood and remains shrouded in mystery.

Propensity score matched analysis comparing the clinical outcome of Klebsiella pneumoniae and Escherichia coli causing community-onset monomicrobial bacteremia

Bacteremia is a life-threatening condition that is associated with substantial healthcare costs. Escherichia coli and Klebsiella pneumoniae are the leading causes of community-onset gram-negative bacteremia. However, a comprehensive comparison between these pathogens involved in bacteremia episodes has yet to be reported.In this retrospective cohort study, adults with community-onset monomicrobial bacteremia caused by E coli or K pneumoniae were recruited in the emergency department of a medical center during a 6-year period, and the clinical variables were collected retrospectively from medical records. The complicated abscess occurrence was determined through imaging studies, according to the opinion of an infectious disease consultant. According to the independent predictors of 28-day mortality identified through multivariate regression analyses, patients in the E coli group were propensity score matched (PSM) in a 1:1 ratio to those in the K pneumoniae group.A total of 274 and 823 adults with K pneumoniae and E coli bacteremia were included in the present study. The K pneumoniae group had more patients with fatal comorbidities (McCabe classification), critical illness (Pitt bacteremia score ≥ 4) at bacteremia onset, and initial syndrome (e.g., severe sepsis and septic shock) as well as a higher crude mortality rate than did the E coli group. After appropriate matching, no significant differences were observed in the critical illness at bacteremia onset, initial syndrome, major comorbidities, and comorbidity severity of the 2 groups (E coli, n = 242; K pneumoniae, n = 242). Furthermore, despite similar 14- and 28-day crude mortality rates between the 2 PSM groups, more frequent abscess occurrences and a longer length of hospitalization were observed in the K pneumoniae group than in the E coli group.Conclusively, numerous clinical features at initial presentations varied between the E coli and K pneumoniae groups. Despite conducting a PSM analysis to control the differences in the baseline characteristics, a longer length of hospitalization and more frequent abscess occurrences were observed in the K pneumoniae group than in the E coli group.

Clinical Characteristics of Bacteremia Caused by Extended-spectrum Beta-lactamase-producing Escherichia coli at a Tertiary Hospital

Objective In recent years, infection caused by extended-spectrum beta-lactamase (ESBL)-producing organisms has become an important issue. However, comparative studies of the bacteremia caused by ESBL Enterobacteriaceae and non-ESBL Enterobacteriaceae are extremely rare in Japan. This study aimed to assess the risk factors and prognosis of patients with bacteremia due to ESBL Escherichia coli (E. coli). Methods The medical records of 31 patients with ESBL E. coli bacteremia and 98 patients with non-ESBL E. coli bacteremia who had been admitted to Osaka City University Hospital between January 2011 and June 2015 were retrospectively reviewed. The patient backgrounds, risk factors for infection, and prognosis were evaluated. Results The male-to-female ratio, mean age, underlying disease, leukocyte count, and C-reactive protein (CRP) level did not differ between the patients in the ESBL E. coli bacteremia and non-ESBL E. coli bacteremia groups. The mean Sequential Organ Failure Assessment (SOFA) score for patients with ESBL and non-ESBL E. coli bacteremia were 3.6 and 3.8, respectively. Further, the mortality did not differ between the two groups (9.7% vs 9.2%). However, the independent predictors associated with ESBL E. coli bacteremia according to a multivariate analysis were the use of immunosuppressive drugs or corticosteroids (p=0.048) and quinolones (p=0.005) prior to isolation. The mortality did not differ between the carbapenem and tazobactam/piperacillin (TAZ/PIPC) or cefmetazole (CMZ) groups for the patients with ESBL E. coli bacteremia. Conclusion Whenever we encountered patients with a history of immunosuppressive drug, corticosteroid, quinolone administration, it was necessary to perform antibiotic therapy while keeping the risk of ESBL E. coli in mind.

Clinical Characteristics of Methicillin-resistant Coagulase-negative Staphylococcal Bacteremia in a Tertiary Hospital

Objective Coagulase-negative staphylococci are among the most frequently isolated microorganisms in blood cultures. The aim of this study was to assess [1] the clinical characteristics of methicillin-resistant, coagulase-negative staphylococci bacteremia and [2] the susceptibility of the isolated bacteria to glycopeptides. Methods We retrospectively reviewed the medical records of 70 patients from whom methicillin-resistant coagulase-negative staphylococci had been isolated at Osaka City University Hospital between January 2010 and December 2013. We evaluated the patients' background, severity and prognosis of the disease, and the susceptibility of the isolated methicillin-resistant coagulase-negative staphylococci to glycopeptides. Results Out of the 70 patients tested, 28 (40.0%) had leukemia, and 36 (51.4%) had been treated for febrile neutropenia. Infection with Staphylococcus epidermidis accounted for 78.6% of patients. Thirty-nine cases (55.7%) were related to intravascular catheters, and 39 (55.7%) were treated using teicoplanin as a first-line therapy. The 30-day mortality rate was 4.3%. Regarding susceptibility, 20% of all isolates were non-susceptible to teicoplanin. According to multivariate analyses, it was observed that premedication using glycopeptides was independently associated with teicoplanin non-susceptibility (p=0.03; hazard ratio = 5.64; 95% confidence interval, 1.16-26.76). Conclusion Our results suggest that clinicians must use glycopeptides appropriately to prevent the development of further antibiotic resistance in methicillin-resistant coagulase-negative staphylococci.

Serum Alkaline Phosphatase Levels Predict Infection-Related Mortality and Hospitalization in Peritoneal Dialysis Patients

BACKGROUND

Serum alkaline phosphatase (ALP) levels have been reported to be associated with all-cause and cardiovascular mortality in peritoneal dialysis (PD) patients. However, it is unclear whether serum ALP levels predict infection-related clinical outcomes in PD patients. The aim of this study was to determine the relationships between serum ALP levels, infection-related mortality and hospitalization in PD patients.

METHODS

PD patients from the Clinical Research Center registry for end-stage renal disease, a multicenter prospective observational cohort study in Korea, were included in the present study. Patients were categorized into three groups by serum ALP tertiles as follows: Tertile 1, ALP <78 U/L; Tertile 2, ALP = 78-155 U/L; Tertile 3, ALP >155 U/L. Tertile 1 was used as the reference category. The primary outcomes were infection-related mortality and hospitalization.

RESULTS

A total of 1,455 PD patients were included. The median follow-up period was 32 months. The most common cause of infection-related mortality and hospitalization was PD-related peritonitis. Multivariate Cox regression analyses showed that patients in the highest tertiles of serum ALP levels were at higher risk of infection-related mortality (HR 2.29, 95% CI, 1.42-5.21, P = 0.008) after adjustment for clinical variables. Higher tertiles of serum ALP levels were associated with higher risk of infection-related hospitalization (Tertile 2: HR 1.56, 95% CI, 1.18-2.19, P = 0.009, tertile 3: HR 1.34, 95% CI, 1.03-2.62, P = 0.031).

CONCLUSIONS

Our data showed that elevated serum ALP levels were independently associated with a higher risk of infection-related mortality and hospitalization in PD patients.

[Rare infection--prolonged A. naeslundii bacteremia caused by severe caries]

Actinomyces is an anaerobic, gram positive, rod shape bacteria that doesn't create spores. Actinomyces is part of the mouth, intestines, vagina and upper respiratory system flora. The infection appears mostly on the face, neck, abdomen and pelvis in cases of mucosa injury and most common in immunosuppressed patients. The spread of Actinomyces through the blood system is rare. In this article we present a 9 year old male patient with no history of diseases who was diagnosed with prolonged bacteremia of A. naeslundii without specific infection excluding severe caries. Characterization of bacteria from the blood culture was performed by molecular biology and the patient was treated with Ampicillin and tooth extraction that led to the disappearance of the bacteremia.

Rhodococcus bacteremia in cancer patients is mostly catheter related and associated with biofilm formation

Rhodococcus is an emerging cause of opportunistic infection in immunocompromised patients, most commonly causing cavitary pneumonia. It has rarely been reported as a cause of isolated bacteremia. However, the relationship between bacteremia and central venous catheter is unknown. Between 2002 and 2010, the characteristics and outcomes of seventeen cancer patients with Rhodococcus bacteremia and indwelling central venous catheters were evaluated. Rhodococcus bacteremias were for the most part (94%) central line-associated bloodstream infection (CLABSI). Most of the bacteremia isolates were Rhodococcus equi (82%). Rhodococcus isolates formed heavy microbial biofilm on the surface of polyurethane catheters, which was reduced completely or partially by antimicrobial lock solution. All CLABSI patients had successful response to catheter removal and antimicrobial therapy. Rhodococcus species should be added to the list of biofilm forming organisms in immunocompromised hosts and most of the Rhodococcus bacteremias in cancer patients are central line associated.

Clinical characteristics and outcomes of patients with extended-spectrum β-lactamase-producing bacteremias in the emergency department

Extended-spectrum β-lactamase (ESBL)-producing bacteria have been spreading from hospitals to communities. Despite this, there are limited emergency department (ED) patient-based studies about these bacteremias. A retrospective matched case-control study with a ratio of 1:3 was conducted at a university hospital. The case group consisted of patients aged >16 years with ESBL-producing bacteremias in the ED. Patients matched for age and sex with non-ESBL-producing bacteremias were sampled as the control group. Finally, 64 episodes of ESBL-producing Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis bacteremias were included in our study. The median age of case patients was 71 years, and 29 (45.3%) were males. The most common type of infection was urinary tract infection (71.9%), followed by intra-abdominal infection (12.5%). Inappropriate empirical antibiotics therapy was prescribed in 87.5% of case patients, which was significantly higher than the control group (13.0%; p < 0.001). Patients with inappropriate empirical antibiotics had a significantly longer hospital stay than those with appropriate empirical antibiotics (p < 0.001). Multivariate analysis showed that hospital-acquired infection, urinary catheterization, and previous antibiotics use were independent risk factors for the acquisition of ESBL-producing bacteremia. The 28-day mortality rate of case patients was 18.8%. Whether they received appropriate empirical antibiotics treatment or not, there was no statistical difference in the mortality of patients with ESBL-producing bacteremias (p = 0.167). To face these emerging multidrug-resistant bacteria and to guide the empirical antibiotics therapy, it is crucial for emergency physicians to recognize the characteristics and risk factors for ESBL-producing organisms.

Clinical and microbiological characteristics of Chryseobacterium indologenes bacteremia

BACKGROUND/PURPOSE

Reports detailing bacteremia caused by Chryseobacterium indologenes remain limited, with most cases reported in Taiwan. The clinical significance of C. indologenes has not been fully established. This retrospective study investigated the clinical features and antimicrobial susceptibility of C. indologenes bacteremia.

METHODS

Patients with C. indologenes bacteremia were identified at a medical center/teaching hospital in northern Taiwan between January 1, 2004 and January 31, 2008. Clinical features and the antimicrobial susceptibilities of these patients were analyzed.

RESULTS

Sixteen isolates of C. indologenes from 16 episodes in 16 patients were identified, with all patients having underlying diseases. Two patients (12.5%) had polymicrobial bacteremia. The portal of bacteremia was not determined in most cases. Other clinical syndromes included catheter-related bacteremia, urinary tract infection and peritonitis. The majority of patients had undergone invasive procedures. Other associated conditions included immunosuppression, neutropenia and prolonged use of antibiotics. Only three patients were treated with appropriate antibiotics according to minimum inhibitory concentrations. The susceptibilities of isolates to trimethoprim-sulfamethoxazole (75.0%), levofloxacin (62.5%), piperacillin-tazobactam (50.0%), ciprofloxacin (43.75%) and cefepime (12.5%) were variable and the bacteremia-related mortality rate was 6.25%.

CONCLUSION

C. indologenes isolates are resistant to multiple antibiotics, with newer fluoroquinolones and trimethoprim-sulfamethoxazole possibly representing the most appropriate antimicrobial agents to treat infections caused by this pathogen. However, the pathogenicity and factors of virulence for C. indologenes remain unclear, with our study revealing favorable outcomes of C. indologenes bacteremia. Epidemiological surveillance of this organism in Taiwan and extensive worldwide surveillance programs are required.

[Pathophysiological mechanisms of organ dysfunction in sepsis]

Sepsis is defined as the systemic inflammatory response to an infection. The occurrence of organ dysfunction increases the severity of sepsis. Complex interactions between multiple immunomodulating mediators and various cell populations, activated secondarily to the initial infectious insult, promote the development of organ dysfunction in sepsis. Although septic organ dysfunction has long been considered as the end result of chaotic, uncontrolled and deregulated inflammatory cascades, it might instead represent an adaptive response to avoid the occurrence of irreversible tissue damage and end-organ injury. In this article, we review the major mechanisms involved in organ dysfunction during sepsis, and also present the concept of organ dysfunction as an adaptive response to the septic process.

Biliary sepsis caused by Ochrobactrum anthropi

Ochrobactrum anthropi is an emerging pathogen in immunocompromised patients, with the majority of human cases being central venous catheter-related infections. In contrast, O. anthropi-related biliary sepsis is much rare. Herein we report the clinical and microbiological characteristics of O. anthropi-related biliary sepsis in order to increase awareness of the potential role of O. anthropi in this infection. Further extensive epidemiologic studies should be carried out to ascertain the etiologic association between O. anthropi and biliary sepsis and to identify potential hosts and routes of transmission.

Characteristics and outcomes of polymicrobial bloodstream infections in the emergency department: A matched case-control study

OBJECTIVES

Polymicrobial bloodstream infection (BSI) is a critical condition and has been increasingly reported; however, the authors were unable to find an emergency department (ED) patient-based study in the literature.

METHODS

A retrospective matched case-control study with a ratio of 1:3 among patients with polymicrobial BSIs in an ED was conducted. The case group was patients aged > 16 years with polymicrobial BSIs. Patients matched for age and sex with monomicrobial BSIs were sampled as the control group. Demographic information, underlying conditions, microbiologic data, and outcomes were collected for further analysis.

RESULTS

From January 2005 to December 2007, a total of 112 episodes of polymicrobial BSIs among 109 patients were included. Two pathogens were isolated among 87 (77.7%) episodes and three were found among 25 (22.3%) episodes. A history of hospitalization within 90 days was an independent risk factor for polymicrobial BSIs (p = 0.003). Intraabdominal infection (p < 0.001) and respiratory tract infection (p = 0.017) were more likely to be associated with polymicrobial BSIs. Gram-negative and Gram-positive bacteria were documented in 95.5 and 46.4% episodes of polymicrobial BSIs, respectively. Inappropriate antimicrobial treatment was observed in 53.6% of polymicrobial BSIs, but only accounted for 23.8% of monomicrobial BSIs (p < 0.001). The overall 30-day mortality rate of the polymicrobial group was significantly higher than those with monomicrobial BSIs (30.3 and 11.6%, respectively; p < 0.001).

CONCLUSIONS

Patients with polymicrobial BSIs had a high mortality rate. Acknowledgment of the clinical and microbiologic characteristics and recognition of patients at risk for polymicrobial BSIs are critical in EDs.

Rationale of extracorporeal removal of endotoxin in sepsis: theory, timing and technique

Several signs and symptoms in sepsis are due to the presence of endotoxin in the circulation. Both in animal and human models, there is an evident immunological response to the endotoxin insult. Furthermore, altered cardiovascular function, lung dysfunction and acute kidney injury are common in sepsis and endotoxemia. In these circumstances it would be extremely important to identify patients with sepsis in the early phases and to characterize the humoral alterations involved with it, including the identification and quantification of circulating endotoxin. Once this is obtained, it seems logical to try to remove as much of the circulating endotoxin as possible in order to mitigate the clinical effects of this condition. This can be achieved today with a very specific hemoperfusion process utilizing cartridges with immobilized polymixin B in an extracorporeal circuit. This approach seems to provide a significant removal of endotoxin with a significant reduction of its circulating levels. The clinical consequences of this approach can be summarized in a mitigation of the septic cascade in the early phases, with improvement of outcome. Recent clinical results seem to confirm these expectations showing a reduction of mortality in patients with early signs of abdominal sepsis due to recent surgery. This opens a new avenue for intervention in sepsis.

Extended-spectrum beta-lactamase-producing phenotype signifies a poor prognosis for patients with cefpodoxime-resistant Escherichia coli or Klebsiella pneumoniae bacteremia

BACKGROUND AND PURPOSE

Bloodstream infections caused by multidrug-resistant Enterobacteriaceae are a major concern. This study explored the clinical impact of extended-spectrum beta-lactamase (ESBL) production among cefpodoxime-resistant Escherichia coli and Klebsiella pneumoniae bacteremia.

METHODS

The medical charts and microbiological results of patients with cefpodoxime-resistant E. coli or K. pneumoniae bacteremia in a tertiary hospital in southern Taiwan between June 2003 and December 2006 were retrospectively reviewed. The clinical characteristics, medical histories, and clinical outcomes were evaluated. ESBL production was indicated by the double-disk synergy test.

RESULTS

278 episodes of bacteremia caused by cefpodoxime-resistant K. pneumoniae or E. coli were identified, of which 115 (41%) were ESBL producing. Compared with non-ESBL-producing bacteremia, bacteremic episodes caused by ESBL producers were less often community acquired (4.3% vs 26.4%; p < 0.001). Underlying diabetes mellitus (48.7% vs 35.0%; p = 0.02), liver cirrhosis (22.6% vs 11.7%; p = 0.02), or uremia (21.7% vs 3.7%; p < 0.001) were more common in ESBL-producing bacteremia. In contrast, solid tumors were more frequent in non-ESBL-producing bacteremia (44.8% vs 27.8%; p = 0.004). Overall, patients with ESBL-producing bacteremia had higher disease severity indicated by a Pittsburgh bacteremia score > or = 4, longer duration of hospital stay (51.1 days vs 31.9 days; p = 0.007), more admission to intensive care units (19.1% vs 8.0%; p = 0.006), and a higher mortality rate at 28 days (34.8% vs 23.9%; p = 0.03).

CONCLUSIONS

ESBL production signifies a poor clinical outcome for patients with bacteremia caused by cefpodoxime-resistant E. coli or K. pneumoniae.

Venous catheter-associated bacteremia caused by rapidly growing mycobacteria at a medical center in central Taiwan

BACKGROUND AND PURPOSE

Infections due to rapidly growing mycobacteria (RGM) are increasing worldwide, especially in immunocompromised hosts, but data on the clinical features of patients with RGM bacteremia are limited in Taiwan. This study was performed to determine the features associated with RGM.

METHODS

The medical records of 12 patients with RGM bacteremia admitted to the Changhua Christian Hospital, Changhua, Taiwan, from April 2001 to March 2003 were retrospectively studied. Clinical data were reviewed and antimicrobial susceptibility testing of blood isolates by the agar disk elution method was performed.

RESULTS

RGM bacteremia was caused by Mycobacterium fortuitum in 5 patients, Mycobacterium smegmatis in 3, Mycobacterium flavescens in 2, and Mycobacterium abscessus in 2. There were 5 men and 7 women (age range, 4-75 years). All patients had underlying diseases and all of the infections were associated with an indwelling vascular catheter. The time to onset of bacteremia ranged from 1 to 24 months. Fever (n = 11) was the most common presenting symptom. Susceptibility testing revealed a different antibiogram for each species of RGM. The rate of relapsing bacteremia was significantly higher in patients with delayed catheter removal and for whom the catheter was not removed (6/8; 75%) than in patients with timely catheter removal (0/4; 0%) [p = 0.03].

CONCLUSIONS

RGM bacteremia is rare but should be considered in immunocompromised patients with an indwelling venous catheter and undifferentiated fever. Identifying RGM at the species level and performing susceptibility testing are useful for guiding management. The catheter should be removed as soon as possible.

Clinical characteristics and predictors of mortality in patients with Enterobacter aerogenes bacteremia

BACKGROUND AND PURPOSE

Enterobacter aerogenes is increasingly encountered in nosocomial infections. This study aimed to clarify the clinical characteristics and to identify the predictors of mortality in patients with E. aerogenes bacteremia.

METHODS

From March 2001 to April 2007, all patients with positive blood cultures for E. aerogenes at Taipei Veterans General Hospital, Taipei, Taiwan, were enrolled in this retrospective study. The medical records were reviewed for clinical and laboratory data.

RESULTS

Eighty eight patients were included, 9 (10.2%) of whom died of E. aerogenes bacteremia. Most of the patients had comorbidities. Seventy nine patients (89.8%) had nosocomial infections, and 43 patients (48.9%) had polymicrobial infections. Eighty four patients (95.5%) presented with fever. Empirical antimicrobial therapy was administered for 80 patients (90.9%), but was appropriate for only 55 patients (62.5%). Of the 9 patients who died, 8 had polymicrobial infection, 5 of whom had nosocomial pneumonia, and 6 did not receive appropriate antimicrobial therapy. Multivariate analysis indicated that high Acute Physiology and Chronic Health Evaluation (APACHE) II score (>16) [odds ratio (OR), 16.569; 95% confidence interval (CI), 1.24-221.24; p = 0.034] and strains not susceptible to extended-spectrum cephalosporins (OR, 9.21; 95% CI, 1.02-83.04; p = 0.048) were independent risk factors for mortality.

CONCLUSIONS

The severity of E. aerogenes bacteremia, reflected by high APACHE II score and isolation of strains with no susceptibility to extended-spectrum cephalosporins, were independent risk factors for mortality. Patients with severe illness and isolates resistant to extended-spectrum cephalosporins should be treated with more potent antimicrobial agents.

Bacteraemic pneumococcal pneumonia in COPD patients: better outcomes than expected

The purpose of the study was to compare the clinical characteristics and outcomes of bacteraemic pneumococcal pneumonia (BPP) in chronic obstructive pulmonary disease (COPD) and non-COPD patients. A case-control study was conducted. Cases were any adult with BPP and forced expiratory volume in 1 second (FEV(1)) <80% and FEV(1)/forced expiratory vital capacity (FVC) <70%. Controls were patients with BPP without clinical diagnosis of COPD matched 1:2 by age, gender and date of isolation. Variables included co-morbidities, serotypes, pneumonia severity index (PSI), treatment and mortality. There were 45 cases and 90 controls. No significant differences were found in Charlson scores, antibiotic treatment, serotype distribution and severity. Malignancy, shock and mechanical ventilation were less frequent in COPD patients. One patient died vs 14 controls (p = 0.02). In univariate analysis, shock, multilobar involvement, Charlson score, heart failure and absence of COPD were associated with mortality. After adjustment for the presence of shock there were no differences in mortality. BPP presents less frequently with shock and has a lower mortality rate in COPD patients than in non-COPD patients.

Bacteriological profile of neonatal septicaemia in a tertiary hospital in Nigeria

BACKGROUND

Neonatal septicaemia is an important cause of morbidity and mortality. Knowledge of the bacteriological profile of the aetiologic agents is very important and helps to reduce the associated mortality in neonatal septicaemia.

OBJECTIVE

To determine the bacteriological profile of common aetiologic agents of neonatal septicaemia and their antibiotics sensitivity pattern.

METHOD

This study was a retrospective review of all the 390 neonatal blood cultures carried out in the Department of Clinical Microbiology and Parasitology of the National Hospital Abuja, Nigeria over three years (Jan 2002-Dec 2004).

RESULT

The 390 neonatal samples constituted 25% of all blood samples received in the laboratory during the period under review. Twenty-two percent were positive for bacterial growth, yielding gram-negative bacilli (GNB) and gram- positive cocci (GPC) in almost equal proportion, predominantly Klebsiella pneumoniae (86% of GNB) and Staphylococcus aureus (81% of GPC). Although the Klebsiella pneumoniae were multiply-resistant and showed resistance pattern suggestive of Extended-Spectrum Beta Lactamase (ELBS) production they were 100% sensitive to imipenem. The sensitivity of the Staphylococcus aureus isolates to amoxicillin-clavulanic acid, cefuroxime, ciprofloxacin, chloramphenicol and erythromycin were 89%, 85%, 75%, 71% and 64% respectively.

CONCLUSION

A sustainable antibiotic susceptibility surveillance programme coupled with good infection control practices and rational antibiotics use will reduce infection rate, ensure better therapeutic success and prolong the efficacy of available antimicrobials.

N,N′-DIACETYLCHITOBIOSE, AN INHIBITOR OF LYSOZYME, REVERSES MYOCARDIAL DEPRESSION AND LESSENS NOREPINEPHRINE REQUIREMENTS IN ESCHERICHIA COLI SEPSIS IN DOGS

Cardiovascular dysfunction in septic shock (SS) is ascribed to the release of inflammatory mediators. Norepinephrine (NE) is often administered to treat low MAP in SS. We recently found that lysozyme c (Lzm-S) released from leukocytes was a mediator of myocardial depression in an Escherichia coil model of SS in dogs. This effect can be blocked in an in vitro preparation by chitobiose, a competitive inhibitor of Lzm-S. In the present study, we examined whether chitobiose treatment can reverse myocardial depression and obviate NE requirements in two respective canine E. coli preparations. In a 6-h study, we administered chitobiose after 3.5 h of E. coli bacteremia and compared stroke work (SW) and MAP at 6 h with a sepsis control group. In a 12-h study, we determined whether chitobiose treatment can reduce the need for NE requirements during 12 h of bacteremia. In the latter study, either chitobiose or NE was given when MAP decreased approximately 20% from the presepsis value in respective groups. In anesthetized, mechanically ventilated dogs, we monitored hemodynamic parameters during continuous E. coli infusion. In the 6-h study, chitobiose improved SW and MAP at the 6-h period as compared with the nontreated sepsis group. In the 12-h study, SW and MAP increased after chitobiose without the necessity of NE administration. These results suggest that inhibitors of Lzm-S such as chitobiose may improve myocardial depression and reduce the need for NE requirements in SS.

Increased mortality and altered immunity in neonatal sepsis produced by generalized peritonitis

Neonates have a higher prevalence of bacterial sepsis and have greater morbidity and mortality from sepsis than other infants and children. Our understanding of the inflammatory and immunological responses to sepsis is hampered by the lack of appropriate neonatal murine models. In the present report, we have developed a cecal slurry model of generalized peritonitis in neonatal mice (age range, 5-7 days) and compared the outcome and the innate and adaptive cellular responses of these animals with those of the young adult animals (age range, 7-10 weeks) with sepsis induced either by cecal slurry administration or by cecal ligation and puncture. Neonatal mice were more susceptible to sepsis and mounted a markedly attenuated systemic inflammatory response compared with young adult animals (specifically, decreased plasma interferon gamma; interleukins 1alpha and 1beta; regulated on activation, normal T expressed and secreted (RANTES); and tumor necrosis factor alpha concentrations). Compared with young adult animals, septic neonatal mice did not lose significant percentage or absolute number of splenic CD4+ T cells. These findings suggest that the cecal slurry model of generalized peritonitis can produce sepsis in neonatal mice with dose-dependent lethality. Inherent differences in the host response to polymicrobial sepsis between neonatal and young adult animals may explain the increased sensitivity of the neonatal mouse to generalized peritonitis.

[Infective endocarditis. A changing disease]

In spite of the advance in diagnosis and antibiotic and surgical treatment, mortality of infective endocarditis remains high. Recent studies in various countries and in Argentina have shown that the clinical profile of infective endocarditis has changed. Currently the patients are older with higher frequency of degenerative valve disease and prosthetic valve and nosocomial endocarditis. The incidence of Staphylococcus aureus as etiological agent has increased. These changes may justify the absence of decrease in mortality and suggests that more aggressive measures are needed based on prospective, well designed and controlled trials.

Liver function tests in patients with bacteremia

The purpose of this study was to evaluate liver function tests as potential indicators of bacteremia. We examined 156 patients with laboratory-confirmed bacteremia (bacteremia group) and 211 bacteremia-negative patients with bacterial infections (control group). The patients of the two groups had no underlying liver diseases. For patients in the bacteremia group, we analyzed liver function tests results obtained the day when the first positive blood culture was ordered. For those in the control group, the same data were obtained on the day when the first of multiple negative blood cultures was ordered. At t-test analyses, serum levels of gamma-glutamyl transpeptidase (gamma-GT) and alkaline phosphatase (ALP) were significantly higher, and those of albumin, total cholesterol, and cholinesterase were significantly lower in the bacteremia group than in the control group. Multivariate analyses found serum cholinesterase as an independent factor with adjusted odds ratio of 0.319 (per 65 U/L, standard deviation [SD] size). Serum level of C-reactive protein (CRP), on the other hand, showed no significant difference between the two groups. Serum levels of gamma-GT, ALP, albumin, total cholesterol, and cholinesterase more rapidly altered when various bacterial infections accompanied bacteremia. Therefore, they may be useful in detecting sepsis in its early stages.

The effect of S. pneumoniae bacteremia on cerebral blood flow autoregulation in rats

In the present study, we studied the effect of bacteremia on cerebral blood flow (CBF) autoregulation in a rat model of pneumococcal bacteremia and meningitis. Anesthetized rats were divided into five groups (A to E) and inoculated with pneumococci intravenously and normal saline intracisternally (group A, N=10); saline intravenously and pneumococci intracisternally (group B, N=10); pneumococci intravenously and pneumococci intracisternally (group C, N=5); saline intravenously, antipneumococcal antibody intravenously (to prevent bacteremia), and pneumococci intracisternally (group D, N=10); or saline intravenously and saline intracisternally (group E, N=10), respectively. Positive cultures occurred in the blood for all rats in groups A, B, and C, and in the cerebrospinal fluid for all rats in groups D and E. Twenty-four hours after inoculation, CBF was measured with laser-Doppler ultrasound during incremental reductions in cerebral perfusion pressure (CPP) by controlled hemorrhage. Autoregulation was preserved in all rats without meningitis (groups A and E) and was lost in 24 of 25 meningitis rats (groups B, C, and D) (P<0.01). In group A, the lower limit was higher than that of group E (P<0.05). The slope of the CBF/CPP regression line differed between the meningitis groups (P<0.001), being steeper for group B than groups C and D, with no difference between these two groups. The results suggest that pneumococcal bacteremia in rats triggers cerebral vasodilation, which right shifts the lower limit of, but does not entirely abolish, CBF autoregulation in the absence of meningitis, and which may further aggravate the vasoparalysis induced by concomitant pneumococcal meningitis.

Nontyphoidal Salmonella bacteremia in previously healthy children: analysis of 199 episodes

BACKGROUND

Nontyphoidal Salmonella (NTS) bacteremia is not rare in otherwise healthy children in Taiwan. Few studies described the clinical manifestations and outcomes of NTS bacteremia in previously healthy children.

METHODS

Children with blood culture positive for NTS treated at Chang Gung Children's Hospital between May 1996 and June 2003 were identified from the microbiology logbook. Patients who had underlying events or concomitant diseases were excluded.

RESULTS

We evaluated 199 patients. One hundred and eighteen (59.3%) were male children and 184 (92.5%) were between 3 months and 5 years of age. Fever (97.0%) and diarrhea (79.9%) were the most common initial presentations. Leukocytosis (leukocyte >15,000/mm) and elevated serum C-reactive protein concentration (> or =10 mg/L) were present in 14.6% and 79.4% of the patients, respectively. Eighty-three percent of 184 patients with antibiotic treatment received a third- or fourth-generation cephalosporin as definitive antibiotic therapy. Focal suppurative infections were present in 5 children (2.5%) on initial evaluation, and included meningitis in 2 and osteomyelitis in 3. Neither metastatic complications nor clinically recurrent diseases were found during a follow-up period of at least 12 months after treatment. No fatalities occurred in this series.

CONCLUSIONS

In healthy children, NTS bacteremia was relatively benign and extraintestinal focal suppurative infections were infrequently seen. Less than 10 days of appropriate antibiotic treatment is probably adequate for those without a suppurative focus of infection.

Risk factors and outcomes of bloodstream infections with metallo-beta-lactamase-producing Acinetobacter

The spread of Gram-negative bacilli with acquired metallo-beta-lactamase (MBL) threatens the successful treatment of major nosocomial infections. The objective of this study was to evaluate the differences in the clinical characteristics of bacteremia caused by MBL-producing Acinetobacter species and MBL non-producing isolates. Two retrospective case-control studies were conducted using data on patients with Acinetobacter bacteremia, who were admitted between January 2001 and December 2005 at a 1500-bed, tertiary-care teaching hospital. Case group 1 (n=27) included patients from whom imipenem-resistant Acinetobacter was isolated in blood culture, and case group 2 (n=7) consisted of those patients from group 1 who yielded MBL-producing isolates. The control group (n=41) included patients from whom carbapenem-susceptible Acinetobacter isolates were isolated in blood culture. Multivariate analysis revealed that the independent risk factors for imipenem-resistant Acinetobacter bacteremia were neutropenia and prolonged use of carbapenem. The independent risk factors for MBL-producing Acinetobacter bacteremia were neutropenia and prolonged use of cephalosporins. The results of this study suggest that a prolonged use of cephalosporins may be associated with MBL-producing Acinetobacter bacteremia.

Cardiac device infections complicated by erosion

BACKGROUND

Implantation of pacemakers and implantable cardioverter-defibrillators (ICDs) can be complicated by infection and device erosion. It is unclear if the clinical features of patients who have device erosion differ from those without erosion.

METHODS

We retrospectively examined the records of all patients referred for explantation of a pacemaker or defibrillator from January 2000 to May 2005. We examined demographic variables including age, gender, and body mass index (BMI) as well as clinical variables related to erosion and procedural variables.

RESULTS

Seventy-two patients with infected pacemakers or ICDs were identified. Of these cases, 30 (42%) developed infection complicated by erosion, of which 8/28 (29%) were related to ICDs, and 22/44 (50%) were related to pacemakers.

CONCLUSIONS

Device erosion was significantly associated with the presence of a non-systemic infection as opposed to cases without erosion. This finding may have implications in the timing of device re-implantation.

Application of the sequential organ failure assessment (SOFA) score to bacteremic ICU patients

BACKGROUND

Patients admitted to intensive care units (ICUs) are at a high risk of acquiring blood stream infections. We examined whether SOFA score on ICU admission and on the day of bacteremia can predict the occurrence of bacteremia and the outcome of bacteremic ICU patients.

PATIENTS AND METHODS

All patients admitted to a multidisciplinary ICU for more than 48 h from January 1, 2002 to December 31, 2004, were prospectively studied. Demographic, clinical and laboratory data were recorded on admission for all patients and additionally, on the day of the first bacteremic episode for those patients who developed bacteremia. Accordingly, APACHE II and SOFA scores were calculated on the same day.

RESULTS

A total of 185 patients developed one or more episodes of bacteremia, giving an incidence of 9.6 per 1,000 ICU days. The ICU mortality rate was 43.9% for bacteremic and 25.8% for the remaining patients (p < 0.001). Admission SOFA score was independently associated with the occurrence of bacteremia (OR = 1.20, 95% CI: 1.11-1.26, p < 0.001). Among bacteremic patients, SOFA score on the day of bacteremia was the only independent prognostic factor for outcome (OR = 1.44, 95% CI: 1.21-1.71, p < 0.001). When all patients were included in the multivariate analysis, admission SOFA (OR = 1.3, CI: 1.16-1.38, p < 0.001), APACHE II (OR = 1.1, CI: 1.02-1.11, p = 0.003) score and the presence of bacteremia (OR = 1.8, CI: 1.1-2.9, p = 0.023) were independently associated with the outcome.

CONCLUSION

Admission SOFA score is independently associated with the occurrence of ICU-acquired bacteremia, whereas it is not sufficient to predict the outcome of patients who subsequently will develop this complication. However, SOFA score on the first day of bacteremia is an independent prognostic factor for outcome in these patients.

Bactericidal/permeability increasing protein attenuates the myocardial inflammation/dysfunction that occurs with burn complicated by subsequent infection

Intubation and mechanical ventilation after burn contribute to pneumonia-related infection. Although postburn presence or absence of endotoxin has been described, inactivation of Toll-like receptor 4 signaling has been shown to improve postburn organ function, suggesting that LPS participates in burn-related susceptibility to infection. We hypothesized that bactericidal/permeability-increasing protein (rBPI) given postburn would attenuate myocardial inflammation/dysfunction associated with postburn septic challenge given 7 days postburn. Rats were given burn over 40% total body surface area, lactated Ringer 4 ml.kg(-1).% burn(-1); burns received either vehicle or rBPI, 1 mg.kg(-1).h(-1) for 48 h postburn. Postburn day 7, subgroups of burns and shams were given intratracheal Klebsiella pneumoniae, 4 x 10(6) CFU to produce burn complicated by sepsis; additional sham and burn subgroups received intratracheal vehicle to produce sham sepsis. Vehicle-treated groups: 1) sham burn + sham sepsis 2) sham burn + sepsis, 3) burn + sham sepsis, 4) burn + sepsis. rBPI-treated groups: 5) sham burn + sham sepsis, 6) sham burn + sepsis, 7) burn + sham sepsis, 8) burn + sepsis. Cardiomyocyte cytokine secretion and myocardial function were studied 24 h after septic challenge, postburn day 8. Pneumonia-related infection 8 days after vehicle-treated burn produced myocyte cytokine secretion (pg/ml), indicated by increased myocyte TNF-alpha, 549 +/- 46; IL-1beta, 50 +/- 8; IL-6, 286 +/- 3 levels compared with levels in sham myocytes (TNF-alpha, 88 +/- 11; IL-1beta, 7 +/- 1; IL-6, 74 +/- 10; P < 0.05). Contractile dysfunction was evident from lower left ventricular pressure +/-dP/dt values in this group compared with sham. rBPI attenuated myocyte cytokine responses to septic challenge and improved contractile function, suggesting that burn-related mobilization of microbial-like products contribute to postburn susceptibility to infection.

Extraintestinal focal infections in adults with Salmonella enterica serotype Choleraesuis bacteremia

BACKGROUND AND PURPOSE

Salmonella enterica serotype Choleraesuis, which is associated with severe human infections and multidrug resistance, poses a serious problem in Taiwan. The aim of the study was to investigate the epidemiology and clinical features of S. Choleraesuis bacteremia.

METHODS

Medical records and antimicrobial susceptibility of blood isolates were investigated for 43 adults (> or =18 years old) with S. Choleraesuis bacteremia from 1999 to 2005.

RESULTS

The proportion of S. Choleraesuis in non-typhoidal Salmonella bacteremia increased in the latter three years (2003-2005). The elderly with aged-related disorders, and younger patients receiving immunosuppressive therapy for their underlying diseases were two high-risk groups. Twenty cases (47%) had extraintestinal focal infections, including 10 cases of mycotic aneurysm, six of osteomyelitis, and 4 pleuropulmonary infections. Univariate analysis revealed that age > or =50 years was associated with occurrence of endovascular infection (p=0.008), while immunosuppressive therapy was negatively associated with endovascular infection (p=0.043). Significant resistance to first-line antimicrobial agents (i.e., ampicillin, trimethoprim-sulfamethoxazole or chloramphenicol) was noted. All strains were resistant to nalidixic acid, and 56% were resistant to ciprofloxacin. Few (<5%) isolates were resistant to ceftriaxone, and all were susceptible to cefepime, aztreonam, imipenem, meropenem and ertapenem. Multivariate analysis showed that shock (odds ratio [OR], 20.6; 95% confidence interval [CI], 1.8-239.4; p=0.016) and apyrexia (OR, 36.2; 95% CI, 3.7-358.2; p=0.002) were independent risk factors for mortality.

CONCLUSION

S. Choleraesuis bacteremia was usually complicated with extraintestinal focal infections in the elderly. With a high level of resistance among S. Choleraesuis, fluoroquinolones should be avoided for critically ill patients with suspected Salmonella bacteremia.

Non-typhoidal Salmonella bacteremia in adults

BACKGROUND AND PURPOSE

Very few studies have examined prognostic factors in adult patients with non-typhoidal Salmonella (NTS) bacteremia. The purpose of this study was to identify the prognostic factors of these patients.

METHODS

A total of 79 episodes of NTS bacteremia were identified in 73 patients between January 2001 and December 2003. Susceptibilities to various antimicrobials were determined using disk-diffusion tests and National Committee for Clinical Laboratory Standards criteria. Multiple logistic regression was used to evaluate the relationship between patients' characteristics and covariates of mortality.

RESULTS

There were only 5 episodes (6%) of gastroenteritis, two of which were due to Salmonella septicemia contracted abroad. Potentially predisposing factors were identifiable in 51 episodes (65%). Infections in 24 patients (30%) were due to serogroup B Salmonella and in 22 patients (28%), to serogroup C Salmonella. A logistic regression analysis selected two variables as independently influencing prognosis: coma (p=0.006) and septic shock (p=0.002).

CONCLUSIONS

Thus, most adult patients with NTS bacteremia do not develop gastroenteritis. Patients in shock or coma have poor prognosis, and susceptibility to third-generation cephalosporins, cefepime, and carbapenem is high.

Lipoprotein e (P4) of Haemophilus influenzae: role in heme utilization and pathogenesis

Lipoprotein e (P4) of Haemophilus influenzae is a phosphomonoesterase, encoded by the hel gene, that has been implicated in the acquisition of heme by this fastidious organism. However, lipoprotein e (P4) is also involved in the utilization of NAD and NMN. Some reports have concluded that the reported heme-related growth defect actually reflects a growth defect for NAD. In the current study, hel insertion mutants were constructed and a role for e (P4) in heme acquisition was demonstrated independent of its role in NAD or NMN acquisition. In addition, a rat model of infection demonstrated a role for e (P4) in the pathogenesis of invasive disease.

Intractable Bacillus cereus bacteremia in a preterm neonate

Although often regarded as a contaminant, Bacillus spp. have been implicated in serious systemic infections. The incidence of such infections is low with only a few cases reported in the literature. We describe the clinical course of early-onset Bacillus cereus bacteremia in a preterm neonate who was successfully treated with vancomycin.

Coagulation and endothelial dysfunction during longterm hyperdynamic porcine bacteremia--effects of selective inducible nitric oxide synthase inhibition

Coagulation abnormalities have been implicated in the pathogenesis of sepsis and organ dysfunction. Nitric oxide (NO) is regarded as a critical mediator of many vascular pathologies, including sepsis. However, limited evidence is available to document a relationship between NO generated by inducible NO synthase (iNOS) and hemostatic abnormalities in sepsis. Therefore, we evaluated the effects of selective iNOS inhibition on markers of endothelial and coagulation homeostasis in a clinically relevant model of porcine bacteremia induced and maintained for 24 hours (h) with a continuous infusion of live P. aeruginosa. After 12 h of sepsis, animals received either vehicle (Control, n=7) or continuous infusion of selective iNOS inhibitor L-NIL (n=7). Before as well as 12, 18 and 24 h after starting P. aeruginosa following variables related to i) endothelial dysfunction (von Willebrand factor [vWf]; tissue plasminogen activator activity [t-PA]; ii) coagulation (thrombin-antithrombin complexes [TAT]; platelet count); iii) fibrinolysis (t-PA activity, activity of plasminogen activator inhibitor type 1 (PAI-1 act); and iv) oxidative/nitrosative stress (isoprostanes, nitrate/nitrite levels) were measured. L-NIL inhibited sepsis-induced increase in plasma nitrate/nitrite and isoprostanes concentrations, prevented hypotension and acidosis. L-NIL significantly attenuated sepsis-induced rise in plasma vWF and TAT. P. aeruginosa-induced drop in t-PA activity was blunted by iNOS inhibition, while increased PAI-1 and reduced platelet count were not reversed by the treatment. In conclusion, selective iNOS inhibition was associated with attenuation of sepsis-induced coagulation and endothelial dysfunction suggesting the interplay between mediators of vascular system and hemostatic balance. Reduction of oxidative stress probably contributes to the beneficial effects afforded by iNOS blockade.

Clinical significance and distribution of putative virulence markers of 116 consecutive clinical Aeromonas isolates in southern Taiwan

OBJECTIVES

The objectives of this study were to elucidate the clinical manifestations of Aeromonas infections and the association of putative virulence genes with clinical invasiveness.

METHODS

116 consecutive clinical Aeromonas isolates collected from July 1999 to June 2001 in a medical center in southern Taiwan were included. All isolates were identified by biochemical phenotyping and their genomic sequences encoding eight putative virulence factors, including cytolytic enterotoxin (AHCYTOEN), aerolysin (aerA), hemolysin (hlyA), heat-labile enterotoxin (alt), heat-stable enterotoxin (ast), and components of type III secretion system (ascV, aexT and ascF-ascG) were analyzed using polymerase chain reaction and colony blot hybridization. The association of clinical diseases of the patients with the putative virulence genes in the isolates was analyzed.

RESULTS

Sixty-two percent of Aeromonas isolates caused clinically evident infections, of which the major clinical manifestations were primary bacteremia (40%), followed by soft tissue infections (27%), and hepatobiliary tract infections (15%). Liver cirrhosis (36%), malignancy (25%), and hepatobiliary diseases (13%) were the major underlying diseases in patients with Aeromonas bacteremia. The majority (64%) of patients with Aeromonas hepatobiliary infections had underlying hepatobiliary diseases, whereas 71% of those with soft tissue infections had antecedent water- or soil-related injuries. The crude fatality rate for Aeromonas infections was 26%. Aeromonas hydrophila complex was the most common (52%) of the three major complex groups investigated, followed by Aeromonas sobria complex (24%) and Aeromonas caviae complex (23%). None of the eight putative virulence factors was associated with invasiveness or bacteremia.

CONCLUSIONS

Primary bacteremia, soft tissue infections, and hepatobiliary tract infections are the three major clinical manifestations of invasive Aeromonas infections in southern Taiwan. This study found no association between the presence of AHCYTOEN, aerA, hlyA, alt, ast, ascV, aexT or ascF-ascG genes in Aeromonas isolates and the development of extra-intestinal infections or bacteremia.

EFFECTS OF COMBINING INDUCIBLE NITRIC OXIDE SYNTHASE INHIBITOR AND RADICAL SCAVENGER DURING PORCINE BACTEREMIA

Complex interactions of nitric oxide and other free radicals have been implicated in the pathogenesis of sepsis and organ dysfunction. We hypothesized that simultaneous inducible nitric oxide synthase inhibition (L-N6-[1-iminoethyl]-lysine [L-NIL]) and neutralization of superoxide (O2-) (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl [Tempol]) would protect from detrimental consequences of long-term, volume-resuscitated, hyperdynamic porcine bacteremia. In this prospective, randomized, controlled experimental study, 16 anesthetized, mechanically ventilated and instrumented pigs were exposed to 24 h of continuous infusion of live Pseudomonas aeruginosa. After 12 h of hyperdynamic sepsis, animals were randomized to receive either vehicle (control, n = 8) or combination of L-NIL and Tempol (n = 8). Systemic and hepatosplanchnic hemodynamics, oxygen exchange, metabolism, ileal mucosal microcirculation and tonometry, oxidative stress and coagulation parameters were assessed before, 12, 18, and 24 h of P. aeruginosa infusion. Combined treatment inhibited sepsis-induced increase in plasma nitrate/nitrite, 8-isoprostane, and thiobarbituric acid reactive species concentrations, prevented hypotension, and reversed hyperdynamic circulation. Despite lower intestinal macrocirculation, combined regimen attenuated the otherwise progressive deterioration in ileal mucosal microcirculation and prevented mucosal acidosis. Treatment substantially attenuated mesenteric and hepatic venous acidosis, preserved sepsis-induced impairment of hepatosplanchnic redox state, and prevented the development of renal dysfunction. Finally, coinfusion of L-NIL and Tempol largely attenuated the sepsis-induced rise in plasma von Willebrand factor and thrombin-antithrombin complexes. Thus, hemodynamic, microcirculatory, metabolic, renal, and coagulation data indicate that combining inducible inhibition with cell permeable O2(-) radical scavenger afforded significant protection in porcine sepsis, thus suggesting an important interactive role of O2(-) and nitric oxide in mediating organ dysfunction.

The clinical impact of bacteremia in complicated acute pyelonephritis

BACKGROUND

Bacteremia has been considered as a surrogate marker of severe infection in several infectious diseases. However, it remains uncertain whether the presence of bacteremia correlates with severe infection in patients with complicated acute pyelonephritis (APN).

METHODS

We performed a retrospective study to investigate the relationship between the presence of bacteremia and disease severity in complicated APN. To do this, we reviewed medical records from 128 patients diagnosed with complicated APN admitted to Kaohsiung Veterans General Hospital, Taiwan between January, 2003 and December, 2003. In our analysis, we compared clinical presentation, treatment response, and outcome in patients with and without bacteremia.

RESULTS

Fifty-four of 128 patients (42%) were bacteremic. This group of patients presented more frequently with severe sepsis or septic shock (P < 0.001), compared with nonbacteremic patients. Other factors that correlated with the presence of bacteremia were older age, diabetes mellitus, more band forms in neutrophil cell counts, impaired renal function, and a lower level of serum albumin. Using a multivariate logistic regression analysis, we show that lower levels of serum albumin (odds ratio, 0.18; 95% CI, 0.05-0.65; P = 0.008) and presence of severe sepsis (odds ratio, 4.76; 95% CI, 1.43-15.84; P = 0.011) were independent factors associated with bacteremia. Following treatment, the bacteremic group took a longer time to become defervescent than the nonbacteremic group (5.1 +/- 2.3 vs. 4.2 +/- 1.6 days, P = 0.023). Also, the bacteremic group had a greater mean duration of intravenous antibiotics administration and longer hospital stays (P < 0.001). Multiple logistic regression analysis shows that non-Escherichia coli bacteremia, presence of urolithiasis or hydronephrosis, shorter duration of antibiotics administration, and being male were significantly associated with recurrence of urinary tract infection within 6 months.

CONCLUSION

Bacteremia in cases of complicated APN indicates a severe disease, which is more likely to recur in patients with non-E coli bacteremia. Our study showed that bacteremia is indeed a useful clinical indicator of severe disease and, if found, should influence patient management. Therefore, we recommend that blood culture samples should be taken in all patients with complicated APN.

Routine use of the Pneumonia Severity Index for guiding the site-of-treatment decision of patients with pneumonia in the emergency department: a multicenter, prospective, observational, controlled cohort study

BACKGROUND

Although the Pneumonia Severity Index (PSI) has been extensively validated, little is known of the impact of its routine use as an aid to site-of-treatment decisions for patients with pneumonia who present to emergency departments (EDs).

METHODS

A prospective, observational, controlled cohort study of patients with pneumonia was conducted in 8 EDs that used the PSI (PSI-user EDs) and 8 EDs that did not use the PSI (PSI-nonuser EDs) in France. The outcomes examined included the proportion of "low-risk" patients (PSI risk classes I-III) treated as outpatients, all-cause 28-day mortality, admission of inpatients to the intensive care unit, and subsequent hospitalization of outpatients.

RESULTS

Of the 925 patients enrolled in the study, 472 (51.0%) were treated at PSI-user EDs, and 453 (49.0%) were treated at PSI-nonuser EDs; 449 (48.5%) of all patients were considered to be at low risk. In PSI-user EDs, 92 (42.8%) of 215 patients at low risk were treated as outpatients, compared with 56 (23.9%) of 234 patients at low risk in PSI-nonuser EDs. The adjusted odds ratios for outpatient treatment were higher for patients in PSI risk classes I and II who were treated in PSI-user EDs, compared with PSI-nonuser EDs (adjusted odds ratio, 7.0 [95% confidence interval, 2.0-25.0] and 4.6 [95% confidence interval, 1.3-16.2], respectively), whereas the adjusted odds ratio did not differ by PSI-user status among patients in risk class III or among patients at high risk. After adjusting for pneumonia severity, mortality was lower in patients who were treated in PSI-user EDs; other safety outcomes did not differ between patients treated in PSI-user and PSI-nonuser EDs.

CONCLUSIONS

The routine use of the PSI was associated with a larger proportion of patients in PSI risk classes I and II who had pneumonia and who were treated in the outpatient environment without compromising their safety.