Inhibition of endotoxin-induced interleukin 8 release by teicoplanin in human whole blood

Use of surveillance cultures and enteral vancomycin to control methicillin-resistant Staphylococcus aureus in a paediatric intensive care unit

This study assessed the effects of throat and gut surveillance, combined with enteral vancomycin, on gut overgrowth, transmission of methicillin-resistant Staphylococcus aureus (MRSA), infections and mortality in patients admitted to a paediatric intensive care unit (PICU). A 4-year prospective observational study was undertaken with 1241 children who required ventilation for >or=4 days. Patients identified as MRSA carriers following surveillance cultures of throat and rectum received enteral vancomycin. Twenty-nine (2.4%) children carried MRSA, 19 on admission and nine during treatment in the PICU; one patient was not able to be evaluated. Overgrowth was present in 22 (75%) of the carriers. Ten (0.8%) children developed 21 MRSA infections (15 exogenous infections in eight children at a median of 8 days (IQR 3-10.5); five primary endogenous infections at a median of 3 days (IQR 1-25) in three children when they were in overgrowth status; one child developed both types of infection). Enteral vancomycin reduced gut overgrowth significantly, completely preventing secondary endogenous infections. Transmission occurred on nine occasions over a period of 4 years. Four patients died, two (5.9%) with MRSA infection, giving a mortality (11.8%) similar to the study population (9.8%). No emergence of vancomycin-resistant enterococci or S. aureus with intermediate susceptibility to vancomycin was detected. A policy based on throat and gut surveillance, combined with enteral vancomycin, for critically-ill children who were MRSA carriers was found to be effective and safe, and challenges the recommended guidelines of nasal swabbing followed by topical mupirocin.

Comparative effects of ciprofloxacin and ceftazidime on cytokine production in patients with severe sepsis caused by gram-negative bacteria

In the present study the effect of ciprofloxacin versus ceftazidime on concentrations of pro- and anti-inflammatory cytokines in the sera of patients with severe sepsis was evaluated. The study included 58 previously healthy patients suffering from severe sepsis caused by gram-negative bacteria, treated with either ciprofloxacin or ceftazidime after thorough clinical and microbiological evaluation and followed up for clinical outcome. Levels of the proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha), interleukin-1b (IL-1b), IL-6, and IL-8 and of the anti-inflammatory cytokine IL-10, as well as of IL-1 receptor antagonist and soluble TNF receptors I and II, in serum were measured at baseline and 24 and 48 h after the first antimicrobial dose. Mean SAPS-II scores, development of septic shock, and mortality rates were similar in the two groups (43.2 +/- 9.2, 21.4%, and 14.3% in the ceftazidime group versus 49.8 +/- 11.3, 20%, and 13.3% in the ciprofloxacin group). Serum TNF-alpha and IL-6 levels at 24 and 48 h were significantly lower in the ciprofloxacin group, while the IL-10/TNF-alpha ratio was significantly higher, than those for the ceftazidime group. Among patients with high baseline TNF-alpha levels, there were significant increases in the IL-10/TNF-alpha ratio at both 24 and 48 h over that at admission for the ciprofloxacin group, while no differences were noted in the ceftazidime group. These results indicate that ciprofloxacin may have an immunomodulatory effect on septic patients by attenuating the proinflammatory response, while there is no evidence that differences in the cytokines measured have any impact on the final outcome.

Infection in prolonged pediatric critical illness: A prospective four-year study based on knowledge of the carrier state

OBJECTIVE

This study was performed to determine the rate, timing, and incidence density of infections occurring in a subgroup of patients requiring a prolonged stay in a regional pediatric intensive care unit.

DESIGN

Prospective, observational cohort study over 4 yrs.

SETTING

This epidemiologic descriptive study was performed in a university hospital 20-bed pediatric intensive care unit.

PATIENTS

Critically ill children requiring > or = 4 days of intensive care.

INTERVENTIONS

The microbial carrier state of the children was monitored by surveillance cultures of throat and rectum, obtained on admission and twice weekly afterward.

MEASUREMENTS AND MAIN RESULTS

Data are presented on a total of 1,241 children, accounting for 1,443 admissions to the unit, corresponding to 18,203 patient days. The median pediatric index of mortality was 0.063 (interquartile range, 0.025-0.131), and the mortality rate in this subset of children was 9.6%. Five hundred twenty children had infections, an overall infection rate of 41.9% (520 of 1,241); 14.5% (180 of 1,241) of the children developed viral and 33.0% (410 of 1,241) developed bacterial/yeast infections. The incidence of bloodstream infection was 20.1 and lower airway infection 9.1 episodes per 1,000 patient days. We found that 13.3% of the children were infected with a bacterial/yeast microorganism acquired on the pediatric intensive care unit; 4.0% (50 of 1,241) of children developed infections due to resistant microorganisms. There were a total of 803 bacterial/yeast infectious episodes, of which 59.8% (480) were due to microorganisms imported in the patients' admission flora. These primary endogenous infections predominantly occurred within the first week of pediatric intensive care unit stay. The other 38.9% (312) were caused by microorganisms acquired on the pediatric intensive care unit. A total of 38 viral infections (24.5%) were acquired during pediatric intensive care unit stay.

CONCLUSIONS

Two thirds of all infections diagnosed in children with prolonged illness on pediatric intensive care unit were due to microorganisms present in the patients' admission flora.

Antiendotoxin activity of antimicrobial peptides and glycopeptides

An animal study was performed to investigate the efficacy of two glycopeptides and two cationic peptides in the prevention of lethality in a septic shock rat model. Adult Wistar rats were given an intraperitoneal injection of 2x10(10) CFU of Escherichia coli ATCC 25922, with the exception of an uninfected control group (C0). Animals were randomized to receive, immediately after bacterial challenge, intraperitoneally isotonic sodium chloride solution (control group C1), 3 mg/Kg teicoplanin (group 1), 7 mg/Kg vancomycin (group 2), 1 mg/Kg colistin (group 3), 1 mg/Kg buforin II (group 4), or 60 mg/Kg piperacillin (group C(PIP)). In addition, four groups (1a, 2a, 3a, and 4a) received the above mentioned drugs in combination with piperacillin. All compounds and combinations significantly reduced the lethality and the number of E. coli in abdominal fluid compared with C1 group, with the exception of the glycopeptides. Colistin and buforin II combined with piperacillin significantly decreased the lethality compared with piperacillin alone. Finally, colistin, buforin II, and teicoplanin significantly reduced plasma endotoxin concentration in comparison with piperacillin and saline treatment. Antimicrobial peptides and teicoplanin act as antiendotoxin agents and enhance the efficacy of piperacillin.

Effects of antimicrobial agents on spontaneous and endotoxin-induced cytokine release of human peripheral blood mononuclear cells

Because the immunomodulatory effects of antibiotics could possibly influence the degree of the systemic and local response to infection, knowledge of their intrinsic influence on the host's inflammatory response appears to be essential. Therefore, this study investigated the effects of frequently used antimicrobial agents (beta-lactams, quinolones gentamicin, vancomycin and metronidazole) on the in-vitro tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 production of isolated human peripheral blood mononuclear cells (PBMNC), cultured with or without endotoxin, in comparison with those effects obtained in a whole-blood assay system. In the presence of ciprofloxacin, ofloxacin, gentamicin, vancomycin, and metronidazole, a significant inhibition of the endotoxin-stimulated TNF-alpha production of human peripheral blood mononuclear cells (PBMNC) was found at therapeutic levels. Only ofloxacin showed a significant inhibitory influence on the endotoxin-induced IL-6 production of PBMNC. In the whole-blood assay, significant effects were not detectable. None of the antibiotics showed cytotoxicity. It is concluded that, at present, the direct immunological effects of antibiotics should be interpreted carefully with regard to the experimental conditions, and regardless of the therapeutic implications. To assess the potential direct immunomodulatory effect of antimicrobial agents, different cell culture procedures should be used.

Antibiotic induced endotoxin release and clinical sepsis: a review

Sepsis and peritonitis have not lost much of their danger for patients. The mortality rate in peritonitis has only marginally decreased during the last 30 years despite aggressive surgical and sophisticated intensive care treatment. In intra-abdominal infection and peritonitis source control remains the mainstay of treatment, although general principles and denominators of successful source control need to be established. Endotoxin has been recognized as a major player in the pathogenesis of sepsis and its significance in clinical disease has been investigated in clinical studies for more than 20 years. Since the Sixties there is a growing interest in the effect of antibiotics and other compounds on the release of endotoxin. The effect of antibiotics on the release of endotoxin and inflammatory parameters, e.g., cytokines, remains to be clarified despite a growing body of in-vitro studies, animal studies and a few clinical studies. The purpose of this review is to evaluate the evidence of endotoxin release in clinical studies and the effect that antibiotic treatment may have in-vitro, in-vivo and in clinical studies on endotoxin and cytokine release. In-vitro antibiotic-induced endotoxin release may depend on antibiotic class, presence of serum, type of organism, site of antibiotic action and Gram-stain. Endotoxin release may be different in late or early lysis, proportional to the number of killed pathogens. Morphology of bacteria may have an impact on endotoxin release and phagocytosis. Antibiotic-treated animals may show higher endotoxin levels with a higher survival rate than untreated animals. Plasma endotoxin may increase despite decreasing bacteremia. There may be a similar killing rate by different antibiotics but a difference in endotoxin release. Intestinal endotoxin does not necessarily correlate to the level of gram-negative bacteria. However, the alteration of the gut content by pretreatment may be associated with reduced endotoxemia and increased survival. Antibiotic-induced endotoxin release may be different depending on the type of infection, the location of infection, the virulence of strains, Gram-stain, mode of application and dosage of antibiotic. Different antibiotics may induce the release of different forms of endotoxin which may be lethal for sensitized animals. The combination of antibiotics with inhibitors of endotoxin or the pro-inflammatory response may be responsible for increased survival by decrease of endotoxin release. The clinical significance of antibiotic-induced endotoxin release is documented only in a few clinical disorders, e.g., meningitis, urosepsis. The difference in endotoxin release by PBP 2-specific antibiotics, e.g., imipenem, and PBP 3-specific antibiotics, e.g., ceftazidime, may not be visible in each study. Patients with increased multi-organ failure (MOF) scores may profit from treatment with antibiotics known to decrease endotoxin. In conclusion, the clinical significance of antibiotic-induced endotoxin release remains to be clarified. Type of pathogen and its virulence may be more important than recently suggested. gram-positive pathogens were just recently recognized as an important factor for the development of the host response. In case of fever of unknown origin in intensive care patients either failure of treatment, e.g., failure of source control in intra-abdominal infection, or a side effect of antibiotic treatment, e.g., endotoxin release, should be considered as a cause of the fever.

Current treatment of sepsis and endotoxaemia

This article reviews the new criteria for selecting the proper antimicrobial agent and dosage regimen for standard treatment of severe sepsis, with the intention of preventing septic shock. After introducing new concepts on the pathogenesis of sepsis and septic shock, the authors analyse the parameters of beta-lactam antibacterial activity, the antibiotic-induced release of bacterial endotoxin and the interrelationships between pharmacokinetics and pharmacodynamics of antibiotics in the search for an optimum dosage regimen of antimicrobial mono- or polytherapy for severely ill septic patients admitted to the intensive care unit. The mortality rate resulting from severe bacterial sepsis, particularly that associated with shock, still approaches 50% in spite of appropriate antimicrobial therapy and optimum supportive care. Bacterial endotoxins that are part of the cell wall are one of the cofactors in the pathogenesis of sepsis and septic shock and are often induced by antimicrobial chemotherapy, even if administered rationally. Not all antimicrobial agents are equally capable of inducing septic shock; this is dependent on their mechanism of action rather than on the causative pathogen species. The quantity of endotoxin released depends on the drug dose and whether filaments or spheroplast formation predominate. Some antibiotics, such as carbapenems, ceftriaxone, cefepime, glycopeptides, aminoglycosides and quinolones, do not have the propensity to provoke septic shock because their rapid bacterial activity induces mainly spheroplast or fragile spheroplast-like bacterial forms.

Antibiotic-induced release of bacterial cell wall components in the pathogenesis of sepsis and septic shock: a review

This article reviews the new criteria for selecting the proper antimicrobial agent and dosage regimen for standard treatment of severe sepsis, with the intention of preventing septic shock. After introducing new concepts on the pathogenesis of sepsis and septic shock, the authors analyze the parameters of betalactam antibacterial activity, the antibiotic-induced release of bacterial endotoxin and the interrelationships between pharmacokinetics and pharmacodynamics of antibiotics in the search for an optimum dosage regimen of antimicrobial mono- or polytherapy for severely ill septic patients admitted to the intensive care unit.

Selecting antibacterial agents for the control of surgical infection: mini-review

An analysis of the recent literature on the control of surgical infections confirms the role of antimicrobial agents which guarantee valid perioperative antisepsis in both clean and clean-contaminated surgery. Current chemotherapy is able to check serious postoperative infectious complications by reducing the risk of septic shock with use of a glycopeptide-aminoglycoside-betalactam combination together with anti-inflammatory drugs.

The significance of endotoxin release in experimental and clinical sepsis in surgical patients--evidence for antibiotic-induced endotoxin release?

Sepsis and peritonitis remain a serious challenge for surgical patients, despite improvement in surgical therapy and intensive care and the introduction of new powerful antibiotics. Recent in vitro studies revealed the potential of certain antibiotics, e.g. penicillin-binding protein (PBP) 3-specific antibiotics, to cause antibiotic-induced endotoxin release. Other types of antibiotics, e.g., PBP 2-specific antibiotics, were associated with no or less endotoxin release. Further in vitro experiments and investigations in animals support the hypothesis of antibiotic-induced endotoxin release, but there is little clinical evidence. The clinical significance of endotoxin is subject of open dispute with many pro's and contra's. Endotoxin, although an important trigger, may not be the only factor to induce cytokine release, e.g., peptidoglycans were able to stimulate cells to release cytokines. Gram-positive pathogens have gained more importance in clinical sepsis and may not be sufficiently reflected in current clinical studies. The hypothesis that neutralization of endotoxin and pro-inflammatory cytokines is beneficial in sepsis was seriously challenged by the results of recent clinical and experimental studies. The better understanding of mechanisms in endotoxin-induced cell activation and cell, cell-receptor and soluble receptor interactions led to new treatment options. Recent reports on the complex pathogenesis of peritonitis and the detection of pathogen-related factors with intraperitoneal immune response may have implications on clinical studies investigating the potential of new compounds and the effect of antibiotics on endotoxin release. However, only few reports are available on the clinical significance of antibiotic-induced endotoxin release, and association of endotoxin release with pathogens, mortality or alteration of physiological parameters were not observed. With regard to the particulars of these studies, e.g., a small study population or low mortality rate, mortality may not be an ideal outcome parameter for these studies. There is clinical evidence for antibiotic-induced endotoxin release. However, the need for well-designed and performed studies using newly developed monitoring devices in intensive care therapy is obvious.

Plasma concentrations of tumour necrosis factor-alpha and interleukin-6 during burn wound surgery or dressing

BACKGROUND

Clinical deterioration after burn wound manipulation may be related to the release of cytokines including tumour necrosis factor-alpha (TNF) and interleukin-6 (IL-6).

METHODS

The two cytokines were assayed by immunoenzymetric assay in blood samples taken before and during manipulation of the burn wound. An antibiotic, teicoplanin, was administered to half the patients at the start of the procedure in a randomized fashion as part of a separate trial.

FINDINGS

Sixty patients with a median burn size of 8% (range 1-56%) were studied during dressing change (n = 40) or burn excision (n = 20). There was little change in TNF levels between preoperative and recovery samples but IL-6 concentrations increased three-fold, particularly in those with large recent burns or bacteraemia, and were correlated with poor clinical outcome. The presence of teicoplanin did not significantly affect the levels of either cytokine.

INTERPRETATION

The systemic cytokine response to burn wound dressing or debridement is predominantly that of IL-6 and it is not significantly reduced by preventing Gram-positive bacteraemia during the procedure.

Vancomycin down-regulates lipopolysaccharide-induced tumour necrosis factor alpha (TNF alpha) production and TNF alpha-mRNA accumulation in human blood monocytes

The cytokines play an important role in the cascade of the pathological events leading to septic shock. The TNF alpha produced by monocytes/macrophages upon stimulation with bacterial fragments may contribute to induction of this cytokine cascade. Moreover, the antibiotics used for antimicrobial therapy may cause the increase of TNF alpha production due to massive bacterial killing and exposure of monocytes/macrophages to bacterial cell constituents. To investigate the effect of Vancomycin on TNF alpha production, an in vitro model of LPS-stimulated monocytes was used. The level of TNF alpha protein or TNF biological activity were tested in the culture supernatants of monocytes with LPS. Vancomycin down-regulated, in dose-dependent manner, the TNF alpha production. Vancomycin also inhibited TNF alpha-mRNA accumulation in LPS-stimulated monocytes, as assessed by fluorescence in situ hybridization (FISH) in cell suspension. The down-regulation of TNF alpha production in LPS-stimulated monocytes may indicate that inhibition of this cytokine release is one of the important therapeutic effects of Vancomycin in sepsis.