Coagulase-negative staphylococci are associated to the mild inflammatory pattern of healthcare-associated meningitis: a retrospective study

Impact of Subarachnoid Hemorrhage in Ventriculostomy-Related Infections Prospective Comparison of Two Neurosurgical Injury Contexts

BACKGROUND

Long thought to be immune privileged, the central nervous system is far from being devoid of local immunity. Subarachnoid hemorrhage (SAH) and traumatic brain injury represent 2 distinct central nervous system injury situations which, while both exposed to external ventricular drains, present different incidences of ventriculostomy-related infection (VRI). We sought to compare VRI incidence and initial cerebrospinal fluid (CSF) inflammatory profiles in these 2 clinical situations.

METHODS

From 2015 to 2020, 227 patients treated for SAH (193) or traumatic brain injury (34) with an external ventricular drain were prospectively included. CSF samples were sent daily for microbiological examination, cell count, and biochemical analysis. VRI was defined as a positive CSF culture associated with CSF profile modifications and clinical signs. Ventriculostomy-related colonization was defined as positive catheter culture at removal. Positive events were defined as VRI and/or ventriculostomy-related colonization.

RESULTS

Eleven patients suffered from VRI, with an incidence of 3.6 VRI per 1000 catheter-days. All VRIs occurred among SAH patients without a significant difference. Median duration of drainage was 12 (7-18) days, there were no significant differences for known VRI risk factors. Positive events were significantly higher in SAH patients (20.7% vs. 2.9%, P = 0.013). Inflammatory CSF markers and serum white blood cells were higher in SAH patients.

CONCLUSIONS

Local inflammatory markers were markedly higher in SAH than in traumatic brain injury. However, positive events were more frequent in SAH. Furthermore, SAH may be a risk factor for VRI. Hypothesis that a primary injury to the subarachnoid space could impair central nervous system immune functions should be explored.

The Prognostic Nutritional Index and Mortality in Patients With Ventriculoperitoneal Shunt Infection

The objective of this study was to investigate the relationship between mortality and the prognostic nutritional index (PNI) in the pediatric patient group with ventriculoperitoneal shunt (VPS) infection. A total of 63 pediatric patients with a VPS infection and positive cerebrospinal fluid (CSF) culture were retrospectively registered. The CSF specimens were analyzed to conduct culture and microscopic evaluation. A total of 44.4% of the cases were men and 55.6% of the cases were women. Patients were divided into 2 groups (survivor and non-survivor patients). When survivor and non-survivor patients were compared, it was found that CSF leukocytes, CSF glucose, CSF protein, CSF/blood glucose ratio, lymphocyte, albumin, and PNI levels were lower in the non-survivor patients' group. Nevertheless, blood glucose and CRP (C-reactive protein) were significantly higher in the non-survivor patients' group than in the survivor patients' group. In our investigation, we suggested that low PNI was related to high mortality in cases of VPS infection.

Relationship between catheter related cerebrospinal fluid infections and systemic immune-inflammation index

Background

This study investigated the relationship between the systemic immune inflammation index (SII) and catheter-related infections and their effects on prognosis in pediatric patients.

Methods

A total of 56 pediatric patients diagnosed with ventriculoperitoneal (V-P) shunt infection between January 2017 and October 2019 were included. V-P shunt infection diagnosis was made based on clinical findings. All cerebrospinal fluid (CSF) samples were subjected to direct microscopic examination and culture. Protein, glucose, and sodium levels in CSF, CSF leukocytes, and hematological and biochemical parameters were measured.

Results

Fifty-six patients with growth in CSF culture were included in this study. 55.4% of the cases were female and 44.6% male. V-P shunt was detected in 82.1% of the cases and external ventricular drainage (EVD) catheter-related infection in 17.9%. The CSF/blood glucose ratio was significantly lower (p = 0.046), and SII was significantly increased (p = 0.002) in non-coagulase-negative staphylococci.

Conclusions

Early and appropriate antibiotic therapy reduces morbidity and mortality in catheter-related infections. However, it is important to start empirical antibiotherapy until culture results are expected. Therefore, further research on the estimation of possible factors is needed.

Prospective Comparative Study of External Ventricular Drain Catheter Colonization: Antibiotic-Impregnated versus Conventional Drains

OBJECTIVE

Our aim was to compare the prevalence of biofilm formation on antibiotic-impregnated (AIC) versus standard (SC) external ventricular drain (EVD) catheters.

METHODS

From March 2018 to November 2020, all consecutive EVD catheters inserted in adult patients were included. After removal, EVD catheters were analyzed under scanning electronic microscopy, on both extraluminal and intraluminal faces. Standard culture of catheter tips was also performed.

RESULTS

Overall, 114 catheters were included in 101 patients. There were 48 AICs and 66 SCs. Standard culture showed that ventriculostomy-related colonization was more frequent in SC than in AIC (26 vs. 10%; P = 0.06). Gram-negative rods accounted for 25% of ventriculostomy-related colonization in AICs, and none was documented in SCs. Scanning electronic microscopy observation showed mature biofilm on more than 80% of catheters, without significant difference between catheter type. Also, there was no difference between extraluminal and intraluminal colonization rate. There were 2 ventriculostomy-related infections in each group (5% and 3% among AICs and SCs respectively; P = 1).

CONCLUSIONS

Mature biofilm presence on the intraluminal and the extraluminal faces is similar on AICs and SCs. Accordingly, AICs do not seem to efficiently prevent biofilm formation on EVD catheters. The impact of AICs on the microbiological epidemiology of colonizing biofilm should be further evaluated.

Etiology and Outcomes of Healthcare-Associated Meningitis and Ventriculitis—A Single Center Cohort Study

Healthcare associated meningitis and ventriculitis (HCAMV) are serious complications of neurosurgical procedures. We conducted a retrospective cohort study of patients with HCAMV treated at the University Hospital for Infectious Diseases Zagreb during the 2013–2019 period. A total of 144 patients with 151 episodes of HCAMV were included. The most common indications for neurosurgical procedures were brain tumor, hemorrhage and hydrocephalus. Etiology was identified in 90 (59.6%) episodes (either positive CSF culture or positive PCR), and in other 61 (40.39%) the diagnosis of HCAMV was made based on clinical and CSF parameters, without microbiologic confirmation. Carbapenem-resistant Acinetobacter baumannii was the most common pathogen (15.89%), followed by Staphylococcus aureus (13.91%), Pseudomonas aeruginosa (13.25%) and Coagulase negative staphylococci (7.95%). Overall, 24 (16.3%) patients died, and the majority had adverse outcomes, persistent vegetative state (8, 5.56%) and severe disability (31, 21.53%). The worst clinical outcomes were observed in A. baumannii infections. High rate of complications, the need for external ventricular drainage (re)placement often complicated with nosocomial infections and prolonged stay in intensive care units were observed. Clinicians should be aware of local microbial epidemiology on guiding proper empirical antimicrobial treatment in patients with HCAMV.

Trends of Antimicrobial Susceptibility in Clinically Significant Coagulase-Negative Staphylococci Isolated from Cerebrospinal Fluid Cultures in Neurosurgical Adults: a Nine-Year Analysis

Coagulase-negative staphylococci (CoNS) are the main pathogens in health care-associated ventriculitis and meningitis (HCAVM). This study aimed to assess antimicrobial susceptibility. Moreover, the treatment and clinical outcome were described. All neurosurgical adults admitted to one of the largest neurosurgical centers in China with clinically significant CoNS isolated from cerebrospinal fluid cultures in 2012 to 2020 were recruited. One episode was defined as one patient with one bacterial strain. Interpretive categories were applied according to the MICs. The clinical outcomes were dichotomized into poor (Glasgow Outcome Scale 1 to 3) and acceptable (Glasgow Outcome Scale 4 to 5). In total, 534 episodes involving 519 patients and 16 bacteria were analyzed. Over the 9 years, eight antimicrobial agents were used in antimicrobial susceptibility tests, including six in over 80% of CoNS. The range of resistance rates was 0.8% to 84.6%. The vancomycin resistance rate was the lowest, whereas the penicillin resistance rate was the highest. The linezolid (a vancomycin replacement) resistance rate was 3.1%. The rate of oxacillin resistance, representing methicillin-resistant staphylococci, was 70.2%. There were no significant trends of antimicrobial susceptibility over the 9 years for any agents analyzed. However, there were some apparent changes. Notably, vancomycin-resistant CoNS appeared in recent years, while linezolid-resistant CoNS appeared early and disappeared in recent years. Vancomycin (or norvancomycin), the most common treatment agent, was used in 528 (98.9%) episodes. Finally, 527 (98.7%) episodes had acceptable outcomes. It will be safe to use vancomycin to treat CoNS-related HCAVM in the immediate future, although continuous monitoring will be needed. IMPORTANCE Coagulase-negative staphylococci are the main pathogens in health care-associated ventriculitis and meningitis. There are three conclusions from the results of this study. First, according to antimicrobial susceptibility, the rates of resistance to primary antimicrobial agents are high and those to high-level agents, including vancomycin, are low. Second, the trends of resistance rates are acceptable, especially for high-level agents, although long-term and continuous monitoring is necessary. Finally, the clinical outcomes of neurosurgical adults with coagulase-negative staphylococci-related health care-associated ventriculitis and meningitis are acceptable after treatment with vancomycin. Therefore, according to the antimicrobial susceptibility and clinical practice, vancomycin will be safe to treat coagulase-negative staphylococci-related health care-associated ventriculitis and meningitis.

Healthcare-associated ventriculitis: current and emerging diagnostic and treatment strategies

Introduction: Healthcare-associated ventriculitis and meningitis occur after neurosurgical procedures, is associated with an adverse outcome in the majority of patients and represent a diagnostic challenge to clinicians. As the cerebrospinal fluid (CSF) culture is the cornerstone of diagnosis, obtaining CSF studies prior to starting antibiotic therapy is key.Areas covered: This review will evaluate the incidence, risk factors, clinical presentation, diagnosis, empirical intravenous antibiotic therapy, adjunctive intrathecal therapy, microbiology, prognosis, and prevention of HCAVM. We highlight the challenges and limitations of the currently available diagnostic methods and definitions and explore novel technologies. Our review included the search for published literature until June 2020.Expert opinion: Despite available preventive measures, HCAVM continues to occur and to be independently associated with significant neurological morbidity and mortality in the majority of patients. The cornerstone of the diagnosis of HCAVM is a positive CSF culture but the microbiological yield is reduced to ~50% with prior antimicrobial therapy. Although the CSF profile is not affected by antibiotic therapy it has a fair diagnostic accuracy. Future research efforts should concentrate in identifying novel diagnostic tools such as polymerase chain reaction (PCR) or metagenomic sequencing.

Multidrug-Resistant Staphylococcus epidermidis Ventriculostomy-Related Infection Successfully Treated by Intravenous Ceftaroline after Failure of Daptomycin Treatment

BACKGROUND

Ventriculostomy-related infection with multidrug-negative strains are challenging to treat. We report the use of new antibiotics in such a case.

CASE DESCRIPTION

We report the case of a neurosurgical intensive care unit patient who developed ventriculostomy-related infection with a multidrug-resistant Staphylococcus epidermidis. Vancomycin, recommended in such cases, was not used due to high minimal inhibitory concentrations and concerns for lack of pharmacokinetic/pharmacodynamic target attainment. Daptomycin and ceftaroline remained the only treatment options. Daptomycin was shown microbiologically ineffective after 10 treatment days, with undetectable cerebrospinal fluid (CSF) concentration. Ceftaroline, a novel beta-lactam agent to which the strain showed susceptibility, was thus used. Serum and CSF samples were assessed for antibiotic concentrations. Our results show that CSF bacterial clearance was obtained after 6 days of such treatment. Serum and CSF samplings showed low penetration ratios (2.6%-4.8%), probably due to mild inflammatory CSF profile, with CSF concentration at minimal inhibitory concentration level.

CONCLUSIONS

We observed than even in the case of mild meningeal inflammation, ceftaroline penetration in CSF, although moderate, enabled efficient bacterial clearance and clinical efficacy, in adjunction to correct ventriculoperitoneal shunt management.

Prevalence of mupirocin and chlorhexidine resistance among methicillin-resistant coagulase-negative staphylococci isolated during methicillin-resistant Staphylococcus aureus decolonization strategies

BACKGROUND

The widespread of methicillin-resistant Staphylococcus aureus (MRSA) antimicrobial decolonization in the clinical setting may lead to an increase in the prevalence of multiresistance to coagulase-negative staphylococci (CoNS) owing to their selection. This study aimed to investigate the impact of MRSA decolonization strategies, using mupirocin and chlorhexidine, on their CoNS susceptibility.

METHODS

A total of 312 CoNS isolates were collected before starting the decolonization protocols "baseline strains" (BLS) group, 330 isolates were collected after application of the targeted decolonization protocol "targeted decolonization strains" group, and 355 isolates were collected after application of the universal decolonization protocol "universal decolonization strains" group. Methicillin-resistant CoNS (MR-CoNS) were identified and tested for mupirocin and chlorhexidine susceptibilities. Heptaplex polymerase chain reaction assay was applied for simultaneous screening for chlorhexidine (CHX-R) and mupirocin resistance (Mu-R) genes.

RESULTS

Mu-R prevalence of MR-CoNS among the BLS group was considered moderate (9.1%); however, CHX-R in the BLS group was 5.8%, the rate of which significantly increased among the universal decolonization strains group.

DISCUSSION

Both MRSA decolonization strategies have an additional benefit in reducing the prevalence of MR-CoNS. The prevalence Mu-R rate didn't change significantly during either of the MRSA decolonization practices that may be due to the local nature of mupirocin application on the nasal mucosa only. In contrast CHX-R that was found to be significantly higher among the UDS group.

CONCLUSIONS

Our findings indicate that both MRSA decolonization strategies have an additional benefit in reducing the prevalence of MR-CoNS. Although the universal MRSA decolonization has superior efficacy in decolonization of CoNS, it may increase the risk of selecting CHX-R and Mu-R. In addition, other potential resistance genes should be studied.

Durability of antimicrobial activity of antibiotic-impregnated external ventricular drains: a prospective study

Background

Antibiotic-impregnated external ventricular drains (AI-EVDs) have a debated efficacy in clinical studies.

Objectives

Our aim was to assess the durability of antimicrobial activity of AI-EVDs used in clinical settings.

Methods

From April 2017 to January 2018, all consecutive AI-EVDs (Bactiseal™) inserted in adult patients were prospectively included. After removal, each AI-EVD was cultured and assessed for antimicrobial activity on both internal and external sides of AI-EVDs. Catheters were each challenged with a single Staphylococcus strain [MSSA, MRSA or methicillin-resistant Staphylococcus epidermidis (MRSE)]. MS was used to measure residual concentrations of rifampicin and clindamycin.

Results

Sixty-five AI-EVDs were included (56 patients). Among these, 21 were challenged with MSSA, 23 with MRSA and 21 with MRSE. Five ventriculostomy-related colonizations (9%) and two ventriculostomy-related infections (4%) occurred. Staphylococcus was the main bacterium responsible for colonization (4/5). AI-EVD inhibition decreased significantly against MRSA and MRSE according to duration of catheterization (for external and internal sides, P < 0.02) and overall volume of CSF drained (P < 0.005 for both sides against MRSE, P < 0.005 for external side against MRSA), but not against MSSA. Clindamycin concentration was not correlated with duration of catheterization or CSF volume drained, but <20% of initial concentration was recovered even after 5 days of AI-EVD dwelling. Conversely, rifampicin concentration showed a rapid and significant decline correlated to duration and CSF volume (P < 0.001 and P = 0.03, respectively).

Conclusions

Antimicrobial activity of AI-EVDs dropped quickly in vivo. Antimicrobial impregnation did not prevent AI-EVD colonization by susceptible strains in 9% of the cases.

Cerebrospinal fluid pharmacokinetics of ceftaroline in neurosurgical patients with an external ventricular drain

BACKGROUND

Owing to its antibacterial properties, ceftaroline could be attractive for prevention or treatment of bacterial post-neurosurgical meningitis/ventriculitis. However, few data are available concerning its meningeal concentrations.

OBJECTIVES

To investigate ceftaroline CSF pharmacokinetics in ICU patients with an external ventricular drain (EVD).

METHODS

Patients received a single 600 mg dose of ceftaroline as a 1 h intravenous infusion. Blood and CSF samples were collected before and 0.5, 1, 3, 6, 12 and 24 h after the end of the infusion. Concentrations were assayed in plasma and CSF by LC-MS/MS. A two-step compartmental pharmacokinetic analysis was conducted. Ceftaroline plasma data were first analysed, and thereafter plasma parameters estimated and corrected for protein binding of 20% were fixed to fit unbound CSF concentrations. In the final model, parameters for both plasma and CSF data were simultaneously estimated.

RESULTS

Nine patients with an EVD were included. The Cmax was 18.29 ± 3.33 mg/L in plasma (total concentrations) and at 0.22 ± 0.17 mg/L in CSF (unbound concentration). The model-estimated CSF input/CSF output clearance ratio was 9.4%, attesting to extensive efflux transport at the blood-CSF barrier.

CONCLUSIONS

Ceftaroline CSF concentrations are too low to ensure prophylactic protection against most pathogens with MICs between 1 and 2 mg/L, owing to its limited central distribution.

Therapeutic Effect of Linezolid in Children With Health Care-Associated Meningitis or Ventriculitis

We evaluated the efficacy of linezolid treatment in 6 children with health care-associated meningitis or ventriculitis (HCAMV) caused by gram-positive cocci. All children were diagnosed and treated at the Ehime University Hospital between January 2010 and December 2017. Of these, 5 were treated with linezolid as an empirical therapy. In these 5 patients, vancomycin was initially used but was changed to linezolid because of cerebrospinal fluid (CSF) culture positivity (n = 3) and a high minimum inhibitory concentration of vancomycin (n = 2). The most common HCAMV pathogens were methicillin-resistant coagulase-negative staphylococci (n = 3). In 3 patients, vancomycin concentration was low in CSF but reached the target concentration in serum, while linezolid concentration was high in both CSF and serum. HCAMV treatment using antimicrobial agents with poor CSF penetration may increase the likelihood of therapy failure. Linezolid is more susceptible as the first-line treatment for HCAMV compared with vancomycin.

Natural history of ventriculostomy-related infection under appropriate treatment and risk factors of poor outcome: a retrospective study

OBJECTIVE

The authors aimed to describe the natural history of ventriculostomy-related infections (VRIs) under appropriate treatment and to assess risk factors for poor outcome.

METHODS

All patients older than 18 years in whom an external ventricular drain (EVD) had been implanted and who had developed a VRI requiring treatment were included in this retrospective study. D0 was defined as the first day of antibiotic administration. Clinical and biological parameters were compared each day beginning with D1 and ending with D10 to those of D0. The authors defined D0 in a control group as the day a CSF culture came back positive, without any sign of infection. The authors then searched for poor prognostic factors in the VRI group.

RESULTS

Among 567 patients requiring an EVD between January 2007 and October 2017, 39 developed a VRI. Most were monomicrobial infections, and 47 microbes were responsible (45% were gram-positive cocci). Clinical parameters differed significantly from the control group during the first 2 days and then returned to baseline. The CSF parameters differed significantly from the control group for a longer period, returning to baseline after 5 days. CSF sterilization occurred in a median time of 2 days. An intrathecal route or EVD exchange was not associated with a poor outcome. No clinical or biological parameter between D3 and D5 was linked to outcome.

CONCLUSIONS

Clinical status improved faster than CSF parameters (before and after D5, respectively). Some CSF parameters remained abnormal until D10. Body temperature and microbiological cultures normalized faster than other parameters.

Complete Genome Sequences of the Potential Zoonotic Pathogens Staphylococcus felis and Staphylococcus kloosii

Coagulase-negative staphylococci (CoNS) are opportunistic pathogens frequently encountered in nosocomial infections. Animal-associated CoNS pose a zoonotic risk and constitute a potential reservoir for virulence and antimicrobial resistance genes. To improve our knowledge of animal-associated CoNS, we sequenced the complete genomes of Staphylococcus felis (ATCC 49168) and Staphylococcus kloosii (ATCC 43959).