A Myrtus communis extract enriched in myrtucummulones and ursolic acid reduces resistance of Propionibacterium acnes biofilms to antibiotics used in acne vulgaris

BACKGROUND

Recent works present evidence of Propionibacterium acnes growing as a biofilm in cutaneous follicles. This formation of clusters is now considered as an explanation for the in vivo resistance of P. acnes to the main antimicrobials prescribed in acne vulgaris.

PURPOSE

Our objective was to explore this hypothesis and propose a new therapeutic approach focusing on anti-biofilm activity of Myrtacine(®) New Generation (Mediterranean Myrtle extract-Botanical Expertise P. Fabre) alone or combined with antibiotics.

METHODS/RESULTS

Using in vitro models able to promote the growth of adhered bacteria, the loss of sensitivity of P. acnes biofilms (48 h) towards erythromycin and clindamycin was checked considering either sensitive or resistant strains. In the same time, the activity of Myrtacine(®) New Generation against biofilm formation and mature biofilm (48 h) was evaluated. Using a dynamic model of biofilm formation, we noted an inhibition of biofilm formation (addition of Myrtacine(®) New Generation at T 0) and a significant effect on mature biofilm (48 h) for 5 min of contact. This effect was also checked using the static model of biofilm formation for Myrtacine(®) New Generation concentrations ranging from 0.03% to 0.0001%. A significant, dose-dependent anti-biofilm effect was observed and notable even at a concentration lower than the active concentration on planktonic cells, i.e. 0.001%. Finally, the interest of the combination of Myrtacine(®) New Generation with antibiotics was explored. An enhanced efficacy was noted when erythromycin (1000 mg/l) or clindamycin (500 mg/l) was added to 0.001% Myrtacine(®), leading to significant differences in comparison to each compound used alone.

CONCLUSION

The efficiency of Myrtacine(®) New Generation on P. acnes biofilm alone or combined with antibiotics was demonstrated and can lead to consider it as a potent adjunctive product efficient during the antibiotic course for acne vulgaris treatment.

Efficacy of postoperative antibiotic injection in and around ventriculoperitoneal shunt in reduction of shunt infection: A randomized controlled trial

OBJECTIVES

Infection is a common complication of ventriculoperitoneal (VP) shunt surgery. The incidence of shunt infection is still high despite routine administration of perioperative antibiotics. A lower incidence of shunt infection was observed when antibiotic-impregnated shunts (AIS) were used to treat hydrocephalus and a rapid cure was reported in cases of ventriculitis when antibiotics were injected into external ventricular drain (EVD). That is why we theorized that postoperative prophylactic injection of antibiotics in and around the shunt hardware would reduce the incidence of shunt infection.

PATIENTS AND METHODS

A randomized controlled clinical trial where 60 patients up to one year old, diagnosed with congenital hydrocephalus and submitted to VP shunt insertion, were randomly assigned to one of 3 groups. The treatment groups received the conventional perioperative antibiotics in addition to vancomycin and gentamicin injection in the reservoir and around the peritoneal catheter either once (group A) or twice (group B), while the control group (C) received only the conventional perioperative antibiotics. Cases were followed-up for up to 1 year.

RESULTS

The majority of patients were less than 1 month old. The follow-up period ranged from 2 to 12 months with a mean of 8.9 months. The mean duration of onset of infection after surgery was 30 days. Prematurity (p=0.00236), age less than one month (p<0.0001) and duration of surgery of 90 min or more (p<0.00001) were significant risk factors for postoperative shunt infection. Significantly more cases of shunt infection occurred within one month after surgery (p=0.021). The control group had significantly more cases of postoperative shunt infection than the treatment groups (p=0.0042).

CONCLUSIONS

In congenital hydrocephalus patients submitted to VP shunt insertion, injection of prophylactic vancomycin and gentamicin in and around the shunt hardware significantly reduced the incidence of postoperative shunt infection.

Characteristics and Treatment Outcomes of Propionibacterium acnes Prosthetic Shoulder Infections in Adults

P. acnes shoulder prosthetic joint infections were predominantly characterized by pain and functional loss. Inflammatory marker elevation occurred in just under 50% of cases. Isolates were broadly susceptible to guideline concordant antimicrobials. Antibiotic-only and combined antibiotic-surgical intervention outcomes were similar.

Background. Prosthetic joint infections (PJIs) significantly complicate joint arthroplasties. Propionibacterium acnes is an increasingly recognized PJI pathogen, yet limited clinical and therapeutic data exist. We sought to examine characteristics of P. acnes shoulder PJIs and compare surgical and nonsurgical management outcomes.

Methods. A retrospective analysis of P. acnes shoulder PJIs was conducted at an academic center in Baltimore, Maryland from 2000 to 2013.

Results. Of 24 cases of P. acnes shoulder PJIs, 92% were diagnosed after extended culture implementation; 42% in the delayed and 46% in the late postsurgical period. Joint pain and diminished function were the predominant presenting clinical signs. Erythrocyte sedimentation rate and C-reactive protein elevations occurred in 47% and 44%, respectively. All tested isolates were susceptible to β-lactams, moxifloxacin, vancomycin, and rifampin. Clindamycin resistance was identified in 6%. Of the antibiotic-only treated cases, 67% had a favorable clinical outcome compared with 71% (P = 1.0) of cases with a combined antibiotic-surgical approach. Favorable outcome with and without rifampin therapy was 73% and 60% (P = .61), respectively.

Conclusions. Propionibacterium acnes PJI diagnoses increased with extended culture. Inflammatory markers were elevated in a minority of cases. Isolates maintained broad antimicrobial susceptibility. Compared to combined antibiotic-surgical approaches, antibiotic-only approaches were similarly successful in selected cases.

Therapeutic drug monitoring of cerebrospinal fluid vancomycin concentration during intraventricular administration

Limited data are available on intraventricular vancomycin dosing for meningitis. This study explored clinical characteristics that correlated with cerebrospinal fluid (CSF) concentrations. Over a nine-year period, 13 patients with 34 CSF vancomycin concentrations were evaluated. CSF output and time from dose correlated with CSF vancomycin concentration. No relationship was seen with regards to CSF protein, white blood cell count or glucose.

Hepatocyte growth factor in cerebrospinal fluid differentiates community-acquired or nosocomial septic meningitis from other causes of pleocytosis

Background

Due to anatomical restrictions, the inflammatory response to intracerebral bacterial infections exposes swollen brain tissues to pressure and ischemia, resulting in life-threatening damage. Rapid diagnosis and immediate empirical antibiotic therapy is highly important. However, diagnosing meningitis in patients after neurosurgery is complicated, due to brain tissue damage and changes in cerebrospinal fluid (CSF) caused by surgery. Hepatocyte growth factor (HGF) is a local, acute-phase protein with healing properties. Previous studies on community-acquired septic meningitis reported high levels of intrathecally produced HGF. The present study focused on nosocomial meningitis in assessing the levels of HGF in the CSF.

Methods

HGF concentrations (ELISA) and HGF binding to receptors; c-Met receptor and heparan sulfate proteoglycan were determined in CSF samples (surface plasmon resonance). CSF samples from patients with community-acquired or nosocomial meningitis (217 samples from 135 patients) were compared to those from controls without signs of cerebral nervous system involvement (N = 36) and patients with Alzheimer’s disease (N = 20).

Results

Compared to samples from patients that had undergone neurosurgery and had other infectious diseases, CSF samples from patients with nosocomial meningitis had significantly higher HGF concentrations (p < 0.001) and binding affinity to c-Met (p < 0.001) and HSPG (p = 0.043) receptors. The sensitivity and specificity to identify nosocomial septic meningitis were 69.7 and 93.4 %, respectively. The HGF concentration and binding affinity to HGF receptors were significantly higher in CSF from patients with community-acquired septic meningitis compared to patients with aseptic (viral and subacute) meningitis as well as controls (p < 0.001). The sensitivity and specificity to identify community-acquired septic meningitis were 95.4 and 95.7 %, respectively.

Discussion

In febrile nosocomial infections that occurred post neurosurgery, HGF assessment could substantially improve the differentiation of meningitis from other infections and therefore might be a tool for rapid diagnosis, limiting injuries and guiding antibiotic therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12987-015-0020-z) contains supplementary material, which is available to authorized users.

Acute Hospital Admissions Because of Health Care-Related Adverse Events: A Retrospective Study of 5 Specialist Departments

BACKGROUND

Health care-related adverse events (HCRAEs), which should not be confused with (blameworthy) medical errors, are common; they can lead to hospital admissions and can have grave consequences. Although they are sometimes potentially preventable, information is lacking on HCRAEs leading to admission to different departments.

AIM

This study aimed to gain insight into the incidence, type, severity, and preventability of HCRAEs (including adverse drug events) leading to hospitalization to the departments of internal medicine, surgery, orthopedics, neurology, and neurosurgery. Further, we explore if there are differences regarding these HCRAEs between these departments.

METHODS

We retrospectively evaluated the medical records of all patients admitted through the emergency department (ED) in a 6-month period to the departments of internal medicine, surgery, orthopedics, neurology, and neurosurgery. All patients admitted because of HCRAEs were included.

RESULTS

More than one-fifth (21.8%; range 12.0%-47.8%) of all admissions to the 5 departments were due to a HCRAE. Half (49.9%) of these HCRAEs were medication-related and 30.5% were procedure-related. In 6.5% of patients, the HCRAE led to permanent disability and another 4.4% of patients died during hospitalization. HCRAEs treated by internists and neurologists were usually medication-related, whereas HCRAEs treated by surgeons, orthopedic surgeons, and neurosurgeons were usually procedure-related.

CONCLUSION

Hospital admissions to different departments are often caused by HCRAEs, which sometimes lead to permanent disability or even death. Gaining insight into similarities and differences in HCRAEs occurring in different specialties is a starting point for improving clinical outcomes.

Impact of round-the-clock CSF Gram stain on empirical therapy for suspected central nervous system infections

The impact of round-the-clock cerebrospinal fluid (CSF) Gram stain on overnight empirical therapy for suspected central nervous system (CNS) infections was investigated. All consecutive overnight CSF Gram stains between 2006 and 2011 were included. The impact of a positive or a negative test on empirical therapy was evaluated and compared to other clinical and biological indications based on institutional guidelines. Bacterial CNS infection was documented in 51/241 suspected cases. Overnight CSF Gram stain was positive in 24/51. Upon validation, there were two false-positive and one false-negative results. The sensitivity and specificity were 41 and 99 %, respectively. All patients but one had other indications for empirical therapy than Gram stain alone. Upon obtaining the Gram result, empirical therapy was modified in 7/24, including the addition of an appropriate agent (1), addition of unnecessary agents (3) and simplification of unnecessary combination therapy (3/11). Among 74 cases with a negative CSF Gram stain and without formal indication for empirical therapy, antibiotics were withheld in only 29. Round-the-clock CSF Gram stain had a low impact on overnight empirical therapy for suspected CNS infections and was associated with several misinterpretation errors. Clinicians showed little confidence in CSF direct examination for simplifying or withholding therapy before definite microbiological results.

Pathogenesis, clinical course and neuro-radiological signs of Proprionibacterium acnes cerebritis: Case report and literature review

The clinical and neuroimaging characteristics of brain infections related to Propionibacterium acnes are not well-characterized, making early diagnosis and treatment a challenge. More recently, life-threatening central nervous system infections with P. acnes are being reported with increasing frequency as complications of neurointerventional procedures. We present a rare case of P. acnes cerebritis that occurred as a sequela of bare platinum aneurysm coiling and a contaminant of percutaneous angiographic intervention. We include an extensive review of the literature describing the pathogenesis of P. acnes and neuro-radiological signs of brain infections related to this pathogen.

Propionibacterium acnes: from commensal to opportunistic biofilm-associated implant pathogen

Propionibacterium acnes is known primarily as a skin commensal. However, it can present as an opportunistic pathogen via bacterial seeding to cause invasive infections such as implant-associated infections. These infections have gained more attention due to improved diagnostic procedures, such as sonication of explanted foreign materials and prolonged cultivation time of up to 14 days for periprosthetic biopsy specimens, and improved molecular methods, such as broad-range 16S rRNA gene PCR. Implant-associated infections caused by P. acnes are most often described for shoulder prosthetic joint infections as well as cerebrovascular shunt infections, fibrosis of breast implants, and infections of cardiovascular devices. P. acnes causes disease through a number of virulence factors, such as biofilm formation. P. acnes is highly susceptible to a wide range of antibiotics, including beta-lactams, quinolones, clindamycin, and rifampin, although resistance to clindamycin is increasing. Treatment requires a combination of surgery and a prolonged antibiotic treatment regimen to successfully eliminate the remaining bacteria. Most authors suggest a course of 3 to 6 months of antibiotic treatment, including 2 to 6 weeks of intravenous treatment with a beta-lactam. While recently reported data showed a good efficacy of rifampin against P. acnes biofilms, prospective, randomized, controlled studies are needed to confirm evidence for combination treatment with rifampin, as has been performed for staphylococcal implant-associated infections.

Role of Sonication in the Microbiological Diagnosis of Implant-Associated Infections: Beyond the Orthopedic Prosthesis

Implant-associated infections are difficult-to-treat conditions associated with high morbidity, mortality and length of hospitalization. They are characterized by biofilm formation on implant surface, which makes the microbiological diagnosis difficult and requires a complete device removal for the correct management. The sonication method, which is based on the application of long-wave ultrasounds radiating in a liquid medium, has been recently validated for the diagnosis of prosthetic joint infections. Additionally, this technique has been considered a potential tool in order to improve the microbiological diagnosis of infections associated with other foreign bodies, such as breast, urinary, endovascular and cerebral implants. In the present study, the application of sonication in the setting of implant-associated infections other than orthopedics will be reviewed.

Treatment of Gram-positive infections in critically ill patients

Gram-positive bacteria to include methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible Staphylococcus aureus (MSSA), and enterococci, to include vancomycin-resistant enterococci (VRE), display a remarkable array of resistance and virulence factors, which have contributed to their prominent role in infections of the critically ill. Over the last three decades infections with these pathogens has increased as has their overall resistance to available antimicrobial agents. This has led to the development of a number of new antibiotics for the treatment of Gram-positive bacteria. At present, it is important that clinicians recognize the changing resistance patterns and epidemiology of Gram-positive bacteria as these factors may impact patient outcomes. The increasing range of these pathogens, such as the emergence of community-associated MRSA clones, emphasizes that all specialties of physicians treating infections should have a good understanding of the infections caused by Gram-positive bacteria in their area of practice. When initiating empiric antibiotics, it is of vital importance that this therapy be timely and appropriate, as delays in treatment are associated with adverse outcomes. Although vancomycin has traditionally been considered a first-line therapy for serious MRSA infections, multiple concerns with this agent have opened the door for alternative agents demonstrating efficacy in this role. Similarly, the expansion of VRE as a pathogen in the ICU setting has required the development of agents targeting this important pathogen.

Coagulase-negative staphylococci

The definition of the heterogeneous group of coagulase-negative staphylococci (CoNS) is still based on diagnostic procedures that fulfill the clinical need to differentiate between Staphylococcus aureus and those staphylococci classified historically as being less or nonpathogenic. Due to patient- and procedure-related changes, CoNS now represent one of the major nosocomial pathogens, with S. epidermidis and S. haemolyticus being the most significant species. They account substantially for foreign body-related infections and infections in preterm newborns. While S. saprophyticus has been associated with acute urethritis, S. lugdunensis has a unique status, in some aspects resembling S. aureus in causing infectious endocarditis. In addition to CoNS found as food-associated saprophytes, many other CoNS species colonize the skin and mucous membranes of humans and animals and are less frequently involved in clinically manifested infections. This blurred gradation in terms of pathogenicity is reflected by species- and strain-specific virulence factors and the development of different host-defending strategies. Clearly, CoNS possess fewer virulence properties than S. aureus, with a respectively different disease spectrum. In this regard, host susceptibility is much more important. Therapeutically, CoNS are challenging due to the large proportion of methicillin-resistant strains and increasing numbers of isolates with less susceptibility to glycopeptides.

Antimicrobial treatment options for neurosurgical ventricular shunt infections in children from 1993 to 2012: a systematic review

PURPOSE

The aim of this systematic review was to review studies that existed from 1993 to 2012 regarding antimicrobial treatment options of paediatric neurosurgical shunt.

METHODS

Studies were identified from MEDLINE, Scopus and Cochrane databases using a search strategy that was registered on the PROSPERO database. Studies were included if they had two or more patients, aged less than 18 years, and also specified the organism and antimicrobial treatment that was used.

RESULTS

The search yielded 2,985 articles, and 76 articles were suitable for full review. In the final qualitative analysis, only eight studies were included, involving 86 participants. The most common antimicrobial regimens for Gram-positive infections was intravenous and intrathecal vancomycin (n = 7), followed by intravenous vancomycin monotherapy.

CONCLUSION

This systematic review has shown that there are no prospective randomised studies of antimicrobial treatment options for paediatric neurosurgical patients in the last 20 years, and larger prospective studies are urgently required for this serious infection. There is some limited case series showing the benefits of certain antimicrobials such as vancomycin and ceftriaxone, but a larger case series or randomised controlled trial is required, particularly to establish the benefit, if any, of additional intraventricular antimicrobials.

De Novo meningitis caused by Propionibacterium acnes in a patient with metastatic melanoma

Propionibacterium acnes is a known cause of postneurosurgical meningitis; however, it is rarely implicated in de novo meningitis. Herein we report a case of a 49-year-old male with de novo meningitis caused by P. acnes with metastatic melanoma as the only identified risk factor for his infection.

Clinical characteristics of infections in humans due to Staphylococcus epidermidis

Staphylococcus epidermidis is the most common cause of primary bacteremia and infections of indwelling medical devices. The ability to cause disease is linked to its natural niche on human skin and ability to attach and form biofilm on foreign bodies. This review focuses on the S. epidermidis clinical syndromes most commonly encountered by clinicians and future potential treatment modalities.

Ommaya reservoir-related infections: clinical manifestations and treatment outcomes

OBJECTIVES

As infection is a severe complication of Ommaya reservoirs (OR), and existing data is limited, herein we describe the largest study of the clinical manifestations and treatment outcomes of Ommaya reservoir-related infections (ORRI).

METHODS

We retrospectively reviewed the records of all patients at our institution who had an OR placed, and developed a definite device-related infection between 2001 and 2011.

RESULTS

Among 501 OR placements, 40 patients (8%) developed an ORRI. These presented with meningitis and/or meningoencephalitis (60%), cellulitis (20%), or a combination thereof (20%). Approximately 40% occurred ≤30 days of OR placement, while 60% occurred ≤10 days after the device was last accessed. Only 20% presented with leukocytosis, while another 18% had a normal cerebrospinal fluid (CSF). Gram-positive skin flora accounted >80% of the pathogens. The median hospital stay and duration of antibiotics were 13 and 24 days, respectively. Although mortality rates (≈10%) were similar among all treatment groups (p > 0.99), shorter hospitalization and antimicrobial treatment durations were obtained with early versus late device removal (p < 0.038).

CONCLUSIONS

As clinical symptoms can be non-specific and CSF parameters may be within normal limits, a high suspicion for infection is required. The shortest hospitalization and treatment course was achieved with early device removal.

Bacterial infections of the central nervous system

Bacterial CNS infections comprise a wide spectrum of diseases, which may be acquired outside or inside the hospital, affect immunocompetent or immunocompromised patients, and be associated with trauma or procedures, as well as other exposures.

Propionibacterium acnes: an underestimated pathogen in implant-associated infections

The role of Propionibacterium acnes in acne and in a wide range of inflammatory diseases is well established. However, P. acnes is also responsible for infections involving implants. Prolonged aerobic and anaerobic agar cultures for 14 days and broth cultures increase the detection rate. In this paper, we review the pathogenic role of P. acnes in implant-associated infections such as prosthetic joints, cardiac devices, breast implants, intraocular lenses, neurosurgical devices, and spine implants. The management of severe infections caused by P. acnes involves a combination of antimicrobial and surgical treatment (often removal of the device). Intravenous penicillin G and ceftriaxone are the first choice for serious infections, with vancomycin and daptomycin as alternatives, and amoxicillin, rifampicin, clindamycin, tetracycline, and levofloxacin for oral treatment. Sonication of explanted prosthetic material improves the diagnosis of implant-associated infections. Molecular methods may further increase the sensitivity of P. acnes detection. Coating of implants with antimicrobial substances could avoid or limit colonization of the surface and thereby reduce the risk of biofilm formation during severe infections. Our understanding of the role of P. acnes in human diseases will likely continue to increase as new associations and pathogenic mechanisms are discovered.

Catheter fixation and ligation: a simple technique for ventriculostomy management following endovascular stenting

The object of this study was to describe a unique method of managing ventriculostomy catheters in patients on antithrombotic therapy following endovascular treatment of ruptured intracranial aneurysms. The authors retrospectively reviewed 3 cases in which a unique method of ventriculostomy management was used to successfully avoid catheter-related hemorrhage while the patient was on dual antiplatelet therapy. In this setting, ventriculostomy catheters are left in place and fixed to the calvarium with titanium straps effectively ligating them. The catheter is divided and the distal end is removed. The proximal end can be directly connected to a distal shunt system during this stage or at a later date if necessary. The method described in this report provided a variety of management options for patients requiring external ventricular drainage for subarachnoid hemorrhage. No patient suffered catheter-related hemorrhage. This preliminary report demonstrates a safe and effective method for discontinuing external ventricular drainage and/or placing a ventriculoperitoneal shunt in the setting of active coagulopathy or antithrombotic therapy. The technique avoids both the risk of hemorrhage related to catheter removal and reinsertion and the thromboembolic risks associated with the reversal of antithrombotic therapy. Some aneurysm centers have avoided the use of stent-assisted coiling in cases of ruptured aneurysms to circumvent ventriculostomy-related complications; however, the method described herein should allow continued use of this important treatment option in ruptured aneurysm cases. Further investigation in a larger cohort with long-term follow-up is necessary to define the associated risks of infection using this method.

C-reactive protein in prediction of ventriculoperitoneal shunt-related infection in high-risk patients

BACKGROUND

C-reactive protein (CRP) is an inflammatory marker believed to be of value in the early detection of meningitis. We evaluated its potential as a marker for prediction of shunt-related infection in high-risk subjects.

METHODS

We conducted a prospective pilot study in 26 ventriculoperitoneal shunt procedures; 18 of the patients were considered to be at high risk of infection at the time of shunt insertion. All patients were screened for other disease that could cause, an increase in CRP.

RESULTS

The serum CRP medians were 3.90 mg/L in the whole sample and 5.36 mg/L in the high-risk participants. All four shunt infections occurred in the high-risk group (22.2% of the group), three (75%) of which were in patients with meningitis. The logistic regression model showed that CRP concentrations above the cut-off value of ≥ 7 mg/L were related to shunt infection (p=0.042). The receiving-operating characteristic curve revealed a cutoff point at ≥ 10.1 mg/L (sensitivity 0.75, 1 - specificity 0.18). The calculated area under the curve was 0.744. The sensitivity and specificity in the whole sample and high-risk group were not different (75% and 79%-80%, respectively). The positive post-test probability was 40% in the whole sample and 50% in the high-risk group. The negative post-test probability was 5% and 7%, respectively.

CONCLUSION

Our data suggest that in a patient at high risk of shunt-related infection, the serum CRP concentration can be a valuable predictor of the risk of infection. Further studies in larger samples would be worthwhile.

Infectious intracranial complications in the neuro-ICU patient population

PURPOSE OF REVIEW

To provide an overview of infectious intracranial complications secondary to invasive procedures or trauma in the neuro-ICU patient population. Nosocomial infections of the central nervous system are a serious complication contributing to morbidity, prolonged length of stay in the ICU and/or hospital, and mortality of neurocritical care patients.

RECENT FINDINGS

Any type of neurosurgical interventions, specifically ventriculostomy/external ventricular drainage, constitutes a major risk factor for infectious intracranial complications. Other predisposing factors are comorbidities with immunocompromised state and the presence of a distant focus of infection. The emergence of multiresistant pathogens adds to the complexity of the management of infectious intracranial complications. In recent years, several antimicrobial agents suitable for the treatment of nosocomial central nervous system infections have been extensively studied with respect to pharmacodynamics and pharmacokinetics in serum and - of special importance in the neurocritical care setting - cerebrospinal fluid.

SUMMARY

Despite recent advances in prevention and treatment, the management of nosocomial intracranial infections still poses a challenge to the neuro-ICU specialist and must consider timely diagnosis and prompt initiation of appropriate antibiotic therapy. This review focuses on the definition, epidemiology, clinical features, and therapeutical approach to this distinct complication of neurocritical care.

Sepsis syndrome, bloodstream infections, and device-related infections

The diagnosis of sepsis is challenging given the lack of appropriate diagnostic methods and the inaccuracy of diagnostic criteria. Early resuscitation, intravenous antibiotics, and source control are crucial in the management of septic patients. The treatment of catheter-related bloodstream infection (CRBSI) often comprises 1 to 2 weeks of intravenous antibiotics plus catheter removal. Infections related to surgical devices are more difficult to manage because they require longer duration of therapy and possibly multiple surgical procedures. This review represents an update on the diagnosis and management of sepsis, catheter-related blood stream infections and some clinically important device-related infections.

Evaluation of an institutional guideline for the treatment of cerebrospinal fluid shunt-associated infections

BACKGROUND

Cerebrospinal fluid (CSF) shunt-associated infection is one of the most frequent complications of CSF shunt surgery. We evaluated our institutional guideline for the treatment of shunt-associated infections.

METHODS

We retrospectively analysed all 92 episodes of shunt-associated infections in 78 patients treated in our institution from 2002 to 2008. All patients underwent urgent surgery, i.e. removal of the complete shunt hardware or externalisation of the distal tubing in cases with an infection restricted to the distal shunt (10 %), placement of an external ventricular drainage as necessary and antibiotic therapy. Standard empirical first-line antibiotic treatment consisted of a combination of flucloxacillin and cefuroxime.

RESULTS

We observed 38 % early (<1 month after shunt surgery) and 20 % late infections (> 1 year after shunt placement). Coagulase-negative staphylococci (CoNS) were isolated in 38 %. In 38 % no pathogens could be isolated. Of cases with a first shunt infection, 58 % were initially treated with flucloxacillin/cefuroxime. Only 53 % of all infections were treated successfully with the first course of antibiotics. Only 51 % of bacterial isolates were sensitive to empirical first-line antibiotics. Twenty percent of infections caused by sensitive bacterial isolates nevertheless required second-line antibiotic therapy.

CONCLUSIONS

Urgent surgery for shunt removal and antibiotic therapy will usually cure a shunt-associated infection. The choice of antibiotics should reflect the spectrum of pathogens seen at one's institution, paying particular attention to the role of CoNS isolates, and in vitro sensitivity testing results.

Predictors of ventricular shunt infection among children presenting to a pediatric emergency department

OBJECTIVES

Among a population of children with a ventricular shunt presenting to a pediatric emergency department (ED), and in whom cerebrospinal fluid (CSF) was obtained, we sought to (1) determine the rate of positive CSF bacterial culture and (2) identify clinical predictors of ventricular shunt infection.

METHODS

We performed a retrospective cohort study of children 3 months to 21 years of age evaluated in a single pediatric tertiary ED from 1995 to 2008. All included children had CSF obtained within 24 hours of presentation to the ED. A shunt infection was defined by growth of bacteria in the CSF of a child who underwent shunt removal within 7 days of presentation.

RESULTS

Nine hundred seventy-nine children met the inclusion criteria; 130 patients (13%) had growth of bacteria in CSF, of which 58 (5.9% of total) had a shunt infection. The median time since last shunt revision or replacement was shorter for patients with a shunt infection compared with children without shunt infection (44 vs 209 days, P = 0.001). After adjustment for patient age, the following factors were associated with shunt infection: shunt revision within the prior 90 days (adjusted odds ratio [aOR], 2.4; 95% CI, 1.3-4.4), presence of fever (aOR, 8.4; 95% CI, 4.3-16.3), and white blood cell count greater than 15,000/μL (aOR, 3.2; 95% CI, 1.5-6.6).

CONCLUSIONS

Among children with a ventricular shunt who had CSF obtained in the ED, the presence of recent shunt revision, fever, and leukocytosis was associated with ventricular shunt infection.

[Antibiotic-impregnated catheters. A useful tool against infection]

Progress in the treatment of hydrocephalus and particularly of cerebrospinal fluid (CSF) diversion surgery has been continuous and significant from cranial bandaging, which was one of the initial hydrocephalus treatments in the 16th century, to last-generation CSF shunts. However, infection currently remains the most frequent and serious complication despite the efforts made to prevent it. One of these current prevention measures is the use of antibiotic-impregnated catheters. A retrospective cohort study including shunts and external ventricular drains was designed to assess their efficacy in our scenario. The results show that rifampicin- and clindamycin-impregnated catheters are a helpful tool against CSF shunt-derived infection.

Propionibacterium acnes: infection beyond the skin

Propionibacterium acnes is a Gram-positive bacterium that forms part of the normal flora of the skin, oral cavity, large intestine, the conjunctiva and the external ear canal. Although primarily recognized for its role in acne, P. acnes is an opportunistic pathogen, causing a range of postoperative and device-related infections. These include infections of the bones and joints, mouth, eye and brain. Device-related infections include those of joint prostheses, shunts and prosthetic heart valves. P. acnes may play a role in other conditions, including inflammation of the prostate leading to cancer, SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome, sarcoidosis and sciatica. If an active role in these conditions is established there are major implications for diagnosis, treatment and protection. Genome sequencing of the organism has provided an insight into the pathogenic potential and virulence of P. acnes.

Role of rifampin against Propionibacterium acnes biofilm in vitro and in an experimental foreign-body infection model

Propionibacterium acnes is an important cause of orthopedic-implant-associated infections, for which the optimal treatment has not yet been determined. We investigated the activity of rifampin, alone and in combination, against planktonic and biofilm P. acnes in vitro and in a foreign-body infection model. The MIC and the minimal bactericidal concentration (MBC) were 0.007 and 4 μg/ml for rifampin, 1 and 4 μg/ml for daptomycin, 1 and 8 μg/ml for vancomycin, 1 and 2 μg/ml for levofloxacin, 0.03 and 16 μg/ml for penicillin G, 0.125 and 512 μg/ml for clindamycin, and 0.25 and 32 μg/ml for ceftriaxone. The P. acnes minimal biofilm eradication concentration (MBEC) was 16 μg/ml for rifampin; 32 μg/ml for penicillin G; 64 μg/ml for daptomycin and ceftriaxone; and ≥128 μg/ml for levofloxacin, vancomycin, and clindamycin. In the animal model, implants were infected by injection of 10⁹ CFU P. acnes in cages. Antimicrobial activity on P. acnes was investigated in the cage fluid (planktonic form) and on explanted cages (biofilm form). The cure rates were 4% for daptomycin, 17% for vancomycin, 0% for levofloxacin, and 36% for rifampin. Rifampin cured 63% of the infected cages in combination with daptomycin, 46% with vancomycin, and 25% with levofloxacin. While all tested antimicrobials showed good activity against planktonic P. acnes, for eradication of biofilms, rifampin was needed. In combination with rifampin, daptomycin showed higher cure rates than with vancomycin in this foreign-body infection model.

Neuro-intensive care of patients with acute CNS infections

Infections in the central nervous system (CNS) are caused by a wide range of microorganisms resulting in distinct clinical syndromes including meningitis, encephalitis, and pyogenic infections, such as empyema and brain abscess. Bacterial and viral infections in the CNS can be rapidly fatal and can result in severe disability in survivors. Appropriate identification and acute management of these infections often occurs in a critical care setting and is vital to improving outcomes in this group of patients. This review of diagnosis and management of acute bacterial and viral infections in the CNS provides a general approach to patients with a suspected CNS infection and also provides a more detailed review of the diagnosis and management of patients with suspected bacterial meningitis, viral encephalitis, brain abscess, and subdural empyema.

Progression of cerebrospinal fluid cell count and differential over a treatment course of shunt infection

OBJECT

The physiological reaction of CSF white blood cells (WBCs) over the course of treating a shunt infection is undefined. The authors speculated that the CSF WBC count varies with different infecting organisms in peak level and differential percentage of polymorphonuclear (PMN) leukocytes, lymphocytes, monocytes, and eosinophils. The authors hope to identify clinically useful trends in the progression of CSF WBCs by analyzing a large group of patients with successfully treated shunt infections.

METHODS

The authors reviewed 105 successfully treated cases of shunt infections at Riley Hospital for Children. The study dates ranged from 2000 to 2004; this represented a period prior to the routine use of antibiotic-impregnated shunt catheters. They analyzed the following organisms: coagulase-negative staphylococci, Staphylococcus aureus, Propionibacterium acnes, Streptococcal species, and gram-negative organisms. The initial CSF sample at diagnosis was analyzed, as were levels over 14 days of treatment. Model fitting was performed to generate curves for the expected progression of the WBC counts and the differential PMN leukocytes, lymphocyte, monocyte, and eosinophil percentages.

RESULTS

Gram-negative organisms resulted in a higher initial (p = 0.03) and peak WBC count with a greater differential of PMN leukocytes compared with other organisms. Propionibacterium acnes infections were associated with a significantly lower WBC count and PMN leukocytes percentage (p = 0.02) and higher eosinophil percentage (p = 0.002) than other organisms. The pattern progression of the CSF WBC count and differential percentages was consistent for all infections. There was an initial predominance of PMN leukocytes, followed by a delayed peak of lymphocytes, monocytes, and eosinophils over a 14-day course. All values trended toward zero over the treatment course.

CONCLUSIONS

The initial and peak levels of CSF WBCs vary with the infecting organisms. The CSF cell counts showed a predictable pattern during the treatment of shunt infection. These trends may be useful to the physician in clinical decision making, although there is a wide range of variability.

Efficacy of daptomycin versus vancomycin in an experimental model of foreign-body and systemic infection caused by biofilm producers and methicillin-resistant Staphylococcus epidermidis

Staphylococcus epidermidis is a frequent cause of device-associated infections. In this study, we compared the efficacy of daptomycin versus vancomycin against biofilm-producing methicillin-resistant S. epidermidis (MRSE) strains in a murine model of foreign-body and systemic infection. Two bacteremic biofilm-producing MRSE strains were used (SE284 and SE385). The MIC of daptomycin was 1 mg/liter for both strains, and the MICs of vancomycin were 4 and 2 mg/liter for SE284 and for SE385, respectively. The in vitro bactericidal activities of daptomycin and vancomycin were evaluated by using time-kill curves. The model of foreign-body and systemic infection of neutropenic female C57BL/6 mice was used to ascertain in vivo efficacy. Animals were randomly allocated into three groups (n = 15): without treatment (controls) or treated with daptomycin at 50 mg/kg/day or vancomycin at 440 mg/kg/day. In vitro, daptomycin showed concentration-dependent bactericidal activity, while vancomycin presented time-dependent activity. In the experimental in vivo model, daptomycin and vancomycin decreased liver and catheter bacterial concentrations (P < 0.05) and increased the survival and the number of sterile blood cultures (P < 0.05) using both strains. Daptomycin produced a reduction in the bacterial liver concentration higher than 2.5 log(10) CFU/g compared to vancomycin using both strains, with this difference being significant (P < 0.05) for infection with SE385. For the catheter bacterial concentrations, daptomycin reduced the concentration of SE284 3.0 log(10) CFU/ml more than did vancomycin (P < 0.05). Daptomycin is more effective than vancomycin for the treatment of experimental foreign-body and systemic infections by biofilm-producing methicillin-resistant S. epidermidis.

Central nervous system infection in the pediatric population

Infection of the central nervous system is a life-threatening condition in the pediatric population. Almost all agents can cause infection within the central nervous system and the extent of infection ranges from diffuse involvement of the meninges, brain, or the spinal cord to localized involvement presenting as a space-occupying lesion. Modern imaging techniques define the anatomic region infected, the evolution of the disease, and help in better management of these patients. Acute bacterial meningitis remains a major cause of mortality and long-term neurological disability. Fortunately, the incidence of infection after clean craniotomy is < 5%, but it leads to significant morbidity as well as fiscal loss. The most significant causative factor in postcraniotomy infections is postoperative CSF leak. Cerebral abscess related to organic congenital heart disease is one of the leading causes of morbidity and mortality in the pediatric population. The administration of prophylactic antibiotics is indicated for contaminated and clean-contaminated wounds.

Neurologic emergencies in patients who have cancer: diagnosis and management

The nervous system can be significantly affected by cancer. Neurologic symptoms are present in 30% to 50% of oncologic patients presenting to the emergency department or in neurologic consultation at teaching hospitals. Evaluation and treatment require collaborative effort between specialties. The causes of neurologic emergencies in patients with cancer are mostly related to effects of cancer, toxicities of treatments, infections, and paraneoplastic syndromes. These complications cause significant morbidity and mortality and require prompt and accurate diagnostic and treatment measures. This article reviews the common neurologic emergencies affecting patients with cancer and discusses epidemiology, clinical presentation, diagnosis, and treatment modalities.

Granulomatous Propionibacterium acnes infection after trauma surgery

We report here a rare case of infection caused by Propionibacterium acnes following trauma surgery: a 36-year-old male, accident victim was admitted to the hospital because of polytrauma. He underwent a long-drawn-out surgical intervention and after a free-muscle transfer using the rectus femoris muscle, signs of inflammation were detected in the affected area. Microbiological examination of the wound revealed the presence of P. acnes as the only etiological agent of this infection. Adequate antibiotic treatment with penicillin had been started right after the positive microbiological result. Our data confirm the pathogenic potential of P. acnes in late post-surgical infections, and suggest a proper therapeutic approach with intravenous antibiotics and surgical removal of the infected tissue.