Management of meningitis due to antibiotic-resistant Acinetobacter species

Therapeutic drug monitoring of polymyxin B cerebrospinal fluid concentrations in patients with carbapenem-resistant Gram-negative bacteria-induced central nervous system infection

OBJECTIVES

Central nervous system (CNS) infections caused by carbapenem-resistant Gram-negative bacteria (CR-GNB) present a major health and economic burden worldwide. This multicentre prospective study aimed to assess the feasibility and usefulness of CSF therapeutic drug monitoring (TDM) after intrathecal/intraventricular administration of polymyxin B in patients with CNS infections.

METHODS

Forty-two patients treated with intrathecal/intraventricular administration of polymyxin B against CR-GNB-induced CNS infections were enrolled. CSF trough level (Cmin) was collected beginning on Day 2 post-polymyxin B initiation and thereafter. The primary outcomes were clinical cure and 28-day all-cause mortality.

RESULTS

All patients started with intrathecal/intraventricular administration of polymyxin B at a dose of 5 g/day, corresponding to a median CSF Cmin of 2.93 mg/L (range, 0.21-25.74 mg/L). Clinical cure was 71.4%, and the median CSF Cmin of this group was higher than that of clinical failure group [3.31 (IQR, 1.73-5.62) mg/L versus 2.25 (IQR, 1.09-4.12) mg/L; P = 0.011]. In addition, with MICs ≤ 0.5 mg/L, maintaining polymyxin B CSF Cmin above 2.0 mg/L showed a higher clinical cure rate (P = 0.041). The 28-day all-cause mortality rate was 31.0% and had no association with CSF Cmin.

CONCLUSIONS

After intrathecal/intraventricular administration of polymyxin B, CSF concentrations fluctuated considerably inter- and intra-individual. Polymyxin B CSF Cmin above 2.0 mg/L was associated with clinical cure when MICs were ≤ 0.5 mg/L, and the feasibility of TDM warrants additional clinical studies.

Glioma grade and post-neurosurgical meningitis risk

BACKGROUND

Post-neurosurgical meningitis (PNM) constitutes a grave complication associated with substantial morbidity and mortality. This study aimed to determine the risk factors predisposing patients to PNM following surgery for low- and high-grade gliomas.

METHODS

We conducted a retrospective analysis encompassing all patients who underwent glioma surgery involving craniotomy at Turku University Hospital, Turku, Finland, between 2011 and 2018. Inclusion criteria for PNM were defined as follows: (1) Positive cerebrospinal fluid (CSF) culture, (2) CSF leukocyte count ≥ 250 × 106/L with granulocyte percentage ≥ 50%, or (3) CSF lactate concentration ≥ 4 mmol/L, detected after glioma surgery. Glioma grades 3-4 were classified as high-grade (n = 261), while grades 1-2 were designated as low-grade (n = 84).

RESULTS

Among the 345 patients included in this study, PNM developed in 7% (n = 25) of cases. The median time interval between glioma surgery and diagnosis of PNM was 12 days. Positive CSF cultures were observed in 7 (28%) PNM cases, with identified pathogens encompassing Staphylococcus epidermidis (3), Staphylococcus aureus (2), Enterobacter cloacae (1), and Pseudomonas aeruginosa (1). The PNM group exhibited a higher incidence of reoperations (52% vs. 18%, p < 0.001) and revision surgery (40% vs. 6%, p < 0.001) in comparison to patients without PNM. Multivariable analysis revealed that reoperation (OR 2.63, 95% CI 1.04-6.67) and revision surgery (OR 7.08, 95% CI 2.55-19.70) were significantly associated with PNM, while glioma grade (high-grade vs. low-grade glioma, OR 0.81, 95% CI 0.30-2.22) showed no significant association.

CONCLUSIONS

The PNM rate following glioma surgery was 7%. Patients requiring reoperation and revision surgery were at elevated risk for PNM. Glioma grade did not exhibit a direct link with PNM; however, the presence of low-grade gliomas may indirectly heighten the PNM risk through an increased likelihood of future reoperations. These findings underscore the importance of meticulous post-operative care and infection prevention measures in glioma surgeries.

Intraventricular or intrathecal polymyxin B for treatment of post-neurosurgical intracranial infection caused by carbapenem-resistant gram-negative bacteria: a 8-year retrospective study

PURPOSE

Post-neurosurgical intracranial infection caused by carbapenem-resistant gram-negative bacteria (CRGNB) is a life-threatening complication. This study aimed to assess the current practices and clinical outcomes of intravenous (IV) combined with intraventricular (IVT)/intrathecal (ITH) polymyxin B in treating CRGNB intracranial infection.

METHODS

A retrospective study was conducted on patients with post-neurosurgical intracranial infection due to CRGNB from January 2013 to December 2020. Clinical characteristics and treatment outcomes were collected and described. Kaplan-Meier survival and multivariate logistic regression analyses were performed.

RESULTS

The study included 114 patients, of which 72 received systemic antimicrobial therapy combined with IVT/ITH polymyxin B, and 42 received IV administration alone. Most infections were caused by carbapenem-resistant Acinetobacter baumannii (CRAB, 63.2%), followed by carbapenem-resistant Klebsiella pneumoniae (CRKP, 31.6%). Compared with the IV group, the IVT/ITH group had a higher cerebrospinal fluid (CSF) sterilization rate in 7 days (p < 0.001) and lower 30-day mortality (p = 0.032). In the IVT/ITH group, patients with CRKP infection had a higher initial fever (p = 0.014), higher incidence of bloodstream infection (p = 0.040), lower CSF sterilization in 7 days (p < 0.001), and higher 30-day mortality (p = 0.005) than those with CRAB infection. Multivariate logistic regression analysis revealed that the duration of IVT/ITH polymyxin B (p = 0.021) was independently associated with 30-day mortality.

CONCLUSIONS

Intravenous combined with IVT/ITH polymyxin B increased CSF microbiological eradication and improved clinical outcomes. CRKP intracranial infections may lead to more difficult treatment and thus warrant attention and further optimized treatment.

Clinical characteristics and antimicrobial therapy of healthcare-associated carbapenem-non-susceptible gram-negative bacterial meningitis: a 16-year retrospective cohort study

OBJECTIVE

Healthcare-associated Gram-negative bacterial meningitis is a substantial clinical issue with poor outcomes, especially for neurosurgical patients. Here, we aimed to study the characteristics and treatment options of patients with healthcare-associated carbapenem-non-susceptible (Carba-NS) Gram-negative bacterial meningitis.

METHODS

This observational cohort study was conducted at a teaching hospital from 2004 to 2019. The clinical characteristics of patients with meningitis with Carba-NS and carbapenem-susceptible (Carba-S) bacilli were compared, and the antimicrobial chemotherapy regimens and outcomes for Carba-NS Gram-negative bacterial meningitis were analyzed.

RESULTS

A total of 505 patients were included, of whom 83.8% were post-neurosurgical patients. The most common isolates were Acinetobacter spp. and Klebsiella spp., which had meropenem-resistance rates of 50.6% and 42.5%, respectively, and showed a markedly growing carbapenem-resistance trend. Kaplan-Meier curve analysis revealed that Carba-NS Gram-negative bacilli were associated with a significantly higher in-hospital mortality rate (18.8%, 35/186) compared to the Carba-S group (7.4%, 9/122; P = 0.001). For Carba-NS Enterobacterales meningitis, aminoglycoside-based and trimethoprim-sulfamethoxazole-based regimens yielded significantly higher clinical efficacy rates than non-aminoglycoside-based and non-trimethoprim-sulfamethoxazole-based regimens (69.0% vs. 38.7%, P = 0.019 and 81.8% vs. 46.9%, P = 0.036, respectively). For Carba-NS A. baumannii complex meningitis, tetracycline-based (including doxycycline, minocycline, or tigecycline) therapy achieved a significantly higher clinical efficacy rate (62.9%, 22/35) than the non-tetracycline-based therapy group (40.4%, 19/47; P = 0.044).

CONCLUSIONS

Our findings revealed that Carba-NS Gram-negative bacilli are associated with higher in-hospital mortality in patients with healthcare-associated meningitis. The combination therapies involving particular old antibiotics may improve patients' outcome.

TRIAL REGISTRATION

This study was registered on the Chinese Clinical Trial Register under ChiCTR2000036572 (08/2020).

Rare Cases of Pseudomonas aeruginosa Meningitis in Children: 10-Year Experience in a Single Center

OBJECTIVE

The primary objective was to elucidate the epidemiologic characteristics, risk determinants, and clinical outcomes associated with Pseudomonas aeruginosa-induced meningitis.

METHODS

All cases of meningitis caused by Pseudomonas aeruginosa that were treated at the hospital between 2012 and 2022 were retrospectively analyzed and detailed.

RESULTS

During a 10-year period, only 10 patients satisfied the inclusion criteria. Three patients had previously undergone neurosurgical procedures and 4 patients had leukemia.

CONCLUSIONS

Although Pseudomonas aeruginosa meningitis possesses a low incidence rate, the rate of mortality is high. Patients with leukemia or those who have undergone neurosurgery are the most susceptible to diagnosis. Cases of severe neutropenia present only mild or no cerebrospinal fluid pleocytosis. In patients with sensitive Pseudomonas aeruginosa meningitis, the timely use of anti-Pseudomonas carbapenems for intravenous treatment is highly effective. For drug-resistant Pseudomonas aeruginosa meningitis, intrathecal polymyxins administration can be an effective treatment option.

How to treat severe Acinetobacter baumannii infections

PURPOSE OF REVIEW

To update the management of severe Acinetobacter baumannii infections (ABI), particularly those caused by multi-resistant isolates.

RECENT FINDINGS

The in vitro activity of the various antimicrobial agents potentially helpful in treating ABI is highly variable and has progressively decreased for many of them, limiting current therapeutic options. The combination of more than one drug is still advisable in most circumstances. Ideally, two active first-line drugs should be used. Alternatively, a first-line and a second-line drug and, if this is not possible, two or more second-line drugs in combination. The emergence of new agents such as Cefiderocol, the combination of Sulbactam and Durlobactam, and the new Tetracyclines offer therapeutic options that need to be supported by clinical evidence.

SUMMARY

The apparent limitations in treating infections caused by this bacterium, the rapid development of resistance, and the serious underlying situation in most cases invite the search for alternatives to antibiotic treatment, the most promising of which seems to be bacteriophage therapy.

The Clinical Characteristics, Microbiology and Risk Factors for Adverse Outcomes in Neonates with Gram-Negative Bacillary Meningitis

Background: We aimed to describe the clinical features of Gram-negative bacillary (GNB) meningitis in neonates and investigate the risk factors associated with final adverse outcomes of neonatal GNB meningitis. Methods: From 2003 to 2020, all neonates (aged ≤ 90 days old) with bacterial meningitis who were hospitalized in four tertiary-level neonatal intensive care units (NICUs) of two medical centers in Taiwan were enrolled. Neonates with GNB meningitis were compared with those with Streptococcus agalactiae (group B streptococcus, GBS) meningitis. Results: During the study period, a total of 153 neonates with bacterial meningitis were identified and enrolled. GNB and GBS accounted for 40.5% (n = 62) and 35.3% (n = 54) of all neonatal bacterial meningitis, respectively. In neonates with GNB meningitis, the final mortality rate was 6.5% (4 neonates died); 48 (77.4%) had neurological complications, and 26 (44.8%) of 58 survivors had neurological sequelae at discharge. Although the final outcomes were comparable between neonates with GNB meningitis and those with GBS meningitis, neonates with GNB meningitis were more likely to have more severe clinical manifestations initially and have ventriculomegaly at follow-up. After multivariate logistic regression analysis, neonates with seizure at onset, early onset sepsis, and requirement of surgical intervention for neurological complications were independently associated with final adverse outcomes. Conclusions: GNB meningitis was associated with a high risk of neurological complications and sequelae, although it did not significantly increase the final mortality rate. Close monitoring of the occurrence of neurological complications and advanced therapeutic strategies to optimize the outcomes are urgently needed in the future.

The Iron Content of Human Serum Albumin Modulates the Susceptibility of Acinetobacter baumannii to Cefiderocol

The mortality rates of patients infected with Acinetobacter baumannii who were treated with cefiderocol (CFDC) were not as favorable as those receiving the best available treatment for pulmonary and bloodstream infections. Previous studies showed that the presence of human serum albumin (HSA) or HSA-containing fluids, such as human serum (HS) or human pleural fluid (HPF), in the growth medium is correlated with a decrease in the expression of genes associated with high-affinity siderophore-mediated iron uptake systems. These observations may explain the complexities of the observed clinical performance of CFDC in pulmonary and bloodstream infections, because ferric siderophore transporters enhance the penetration of CFDC into the bacterial cell. The removal of HSA from HS or HPF resulted in a reduction in the minimal inhibitory concentration (MIC) of CFDC. Concomitant with these results, an enhancement in the expression of TonB-dependent transporters known to play a crucial role in transporting iron was observed. In addition to inducing modifications in iron-uptake gene expression, the removal of HSA also decreased the expression of β-lactamases genes. Taken together, these observations suggest that environmental HSA has a role in the expression levels of select A. baumannii genes. Furthermore, the removal of iron from HSA had the same effect as the removal of HSA upon the expression of genes associated with iron uptake systems, also suggesting that at least one of the mechanisms by which HSA regulates the expression of certain genes is through acting as an iron source.

Ceftazidime-Avibactam Treatment for Severe Post-Neurosurgical Meningitis and Abscess Caused by Extended-Spectrum β-Lactamase Escherichia coli in a Pediatric Patient: A Case Report

Post-neurosurgical infections caused by multidrug-resistant Enterobacterales are difficult to treat due to limited therapeutic options. Ceftazidime-avibactam (CAZ-AVI), a combination of cephalosporin and a novel β-lactamase inhibitor, has exhibited potential activity against multi/extensive drug-resistant (MDR/XDR) gram-negative bacilli. Several reports have described the successful treatment of central infections caused by MDR/XDR Pseudomonas aeruginosa or Enterobacterales. However, data on the efficacy and effective drug distribution of CAZ-AVI in the central nervous system (CNS), particularly in children, are lacking. We report a case of a 4-year-old girl with post-neurosurgical meningitis and abscess caused by extended-spectrum β-lactamase-producing Escherichia coli successfully treated with CAZ-AVI. CAZ-AVI therapeutic drug monitoring was performed to evaluate its efficacy and effective drug distribution in the CNS. We measured CAZ (15.6, 7.1, and 3.5 μg/mL) and AVI (4.0, 2.1, and 1.2 μg/mL) in cerebrospinal fluid (CSF) samples obtained 3, 5, and 7 h after the administration of the 15th CAZ-AVI dose (2.5 g, q8h, iv), respectively. We also measured CAZ (57.0 and 25.8 μg/mL) and AVI (11.3 and 4.5 μg/mL) in serum samples obtained 3 and 5 h after the administration, respectively. CAZ-AVI achieved an adequate CSF concentration throughout the drug interval. Our case provides evidence for using CAZ-AVI to treat CNS infections.

Environmental surveillance of ESBL and carbapenemase-producing gram-negative bacteria in a Ghanaian Tertiary Hospital

Background

The burden of antibiotic resistant infection is mainly felt in low-to-middle income countries, where the rate of antimicrobial resistance is largely under-surveyed and under huge pressure from unregulated, disparate and often self-guided access to antimicrobials. Nosocomial infections from hospital environments have been shown to be a particularly prevalent source of multi-drug resistant strains, yet surveillance of hospital environmental contamination is often not investigated.

Methods

The study was prospective, observational and cross-sectional, sampling 231 high and low touch surfaces from 15th March to 13th April 2021, from five wards in the Cape Coast Teaching Hospital, Ghana. Microbial growth in the presence of vancomycin and either meropenem or cefotaxime was examined and bacterial species were identified by MALDI-TOF. The presence of common extended-spectrum β-lactamases (ESBL) and carbapenemase antimicrobial resistance genes (ARG) were identified through PCR screening, which were confirmed by phenotypic antimicrobial susceptibility determination. Isolates positive for carbapenem resistance genes were sequenced using a multi-platform approach.

Results

We recovered microbial growth from 99% of swabs (n = 229/231) plated on agar in the absence of antimicrobials. Multiple sites were found to be colonised with resistant bacteria throughout the hospital setting. Bacteria with multi-drug resistance and ARG of concern were isolated from high and low touch points with evidence of strain dissemination throughout the environment. A total of 21 differing species of bacteria carrying ARG were isolated. The high prevalence of Acinetobacter baumannii carrying bla_NDM-1 observed was further characterised by whole genome sequencing and phylogenetic analysis to determine the relationship between resistant strains found in different wards.

Conclusion

Evidence of multiple clonal incursions of MDR bacteria of high sepsis risk were found in two separate wards for a regional hospital in Ghana. The prevalence of multiple bla_NDM carrying species in combination with combinations of ESBLs was particularly concerning and unexpected in Africa. We also identify strains carrying tet(X3), bla_VIM-5 or bla_DIM-1 showing a high diversity of carbapenamases present as a reservoir in a hospital setting. Findings of multi-drug resistant bacteria from multiple environmental sites throughout the hospital will inform future IPC practices and aid research prioritisation for AMR in Ghana.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-022-01090-2.

Application of therapeutic drug monitoring to the treatment of bacterial central nervous system infection: a scoping review

BACKGROUND

Bacterial central nervous system (CNS) infection is challenging to treat and carries high risk of recurrence, morbidity, and mortality. Low CNS penetration of antibiotics may contribute to poor clinical outcomes from bacterial CNS infections. The current application of therapeutic drug monitoring (TDM) to management of bacterial CNS infection was reviewed.

METHODS

Studies were included if they described adults treated for a suspected/confirmed bacterial CNS infection and had antibiotic drug concentration(s) determined that affected individual treatment.

RESULTS

One-hundred-and-thirty-six citations were retrieved. Seventeen manuscripts were included describing management of 68 patients. TDM for vancomycin (58/68) and the beta-lactams (29/68) was most common. Timing of clinical sampling varied widely between studies and across different antibiotics. Methods for setting individual PK-PD targets, determining parameters and making treatment changes varied widely and were sometimes unclear.

DISCUSSION

Despite increasing observational data showing low CNS penetration of various antibiotics, there are few clinical studies describing practical implementation of TDM in management of CNS infection. Lack of consensus around clinically relevant CSF PK-PD targets and protocols for dose-adjustment may contribute. Standardised investigation of TDM as a tool to improve treatment is required, especially as innovative drug concentration-sensing and PK-PD modelling technologies are emerging. Data generated at different centres offering TDM should be open access and aggregated to enrich understanding and optimize application.

Bacterial microbiota profiling of oyster mushrooms (Pleurotus ostreatus) based on cultivation methods and distribution channels using high-throughput sequencing

The annual consumption and production of oyster mushrooms (Pleurotus ostreatus) have continued to rise due to its nutritive and health-promoting benefits. Cultivated mushrooms are mostly grown in small to medium-scaled scale production plants that present hygienic challenges which could, in turn, increase associated foodborne pathogenic outbreaks. The present study aimed to investigate the shift in microbial ecologies of oyster mushrooms from pre-distribution (cultivation in bottles or on shelves) to post-distribution at supermarkets and open-air markets. Aerobic plate counts and coliforms were quantified using traditional microbiological techniques, and the microbiome associated with oyster mushrooms (n = 70) was analyzed using 16S rRNA amplicon sequencing for an enhanced level of bacterial microbiota profiling. Overall, coliforms recovered from pre-distribution bottle-cultivated mushrooms were 1.9 log CFU/g higher (p < 0.05) than that of shelf-cultivated mushrooms. The mean aerobic plate counts of oyster mushrooms distributed to open-air markets was 1.2 log CFU/g higher (p < 0.05) than packaged mushrooms from supermarkets while there were no significant differences in coliform counts. The pattern of bacterial composition differed by post-distribution channels, with oyster mushrooms collected from the open-air markets demonstrating the richest microbiome diversity. An increase in the relative abundance of Enterobacteriaceae (55-68 %) and Pseudomonadaceae (27-35 %) was observed in pre- and post-distribution mushrooms, respectively. However, no distinct bacterial microbiota differences were observed for the different cultivation methods or different geographical locations for each market type. The current findings add to our understanding of the effects of cultivation methods and commercial distribution channels regarding the microbiome of oyster mushrooms and may inform potential intervention strategies for future production and distribution processes. Furthermore, the tandem analyses of culture-dependent and culture-independent methods can provide more comprehensive information than that obtained when using each approach independently.

Autologous Free Fascia Lata Can Be Used as Dura Graft in the Salvage Treatment of Recalcitrant Postcraniotomy Intracranial Infection Caused by Multidrug-Resistant Gram-Negative Bacteria

Objective

The multidrug-resistant (MDR) gram-negative bacteria-induced intracranial infections after neurosurgical procedures represent a particular therapeutic challenge. Combining the removal of infected prosthetic meninge plus an appropriate antibiotic administration appears to be the only therapeutic strategy likely to succeed when the infection is complicated by artificial dura mater. This study aimed to assess the efficacy of free fascia lata as a substitute for dura reconstruction in the salvage treatment for such recalcitrant nosocomial infections.

Methods

The retrospective, observational study was conducted at Shanghai Tenth hospital. Patients with definite intracranial infection caused by MDR Gram-Negative bacteria who underwent salvage dura reconstruction using autologous free fascia lata were included in the study. Electronic medical data on clinical characteristics, underlying condition, bacterial culture, antibiotic susceptibilities, perioperative management, surgical techniques, outcome, and follow-up were collected and analyzed.

Results

19 patients were included in the study cohort. All these patients underwent salvage surgery, including removal of infected artificial dura substitute, achievement of complete dura seal with free fascia lata, and other adjunctive procedures to drain the CSF and infuse sensitive antimicrobial agents. Intraventricular or intrathecal administration of antibiotics, including Colistin (14 case), Tigecycline (1 case), Amikacin (1 case), was employed in 16 patients. The infection was cured in 17 patients. In-hospital death occurred in 3 patients. One died from multiple system/organ failure, 1 died from massive occipital ICH, 1 died from brain stem hemorrhage after ventricular-peritoneal shunt surgery. The patients remained without clinical evidence of recurrence during the follow-up period.

Conclusion

On the basis of a comprehensive approach to achieving prompt sterilization of causative pathogens and an optimal healing environment, free fascia lata can serve as a simpler but effective option for dura reconstruction even in the setting of a severe septic area for patients who otherwise need much more complicated and demanding tissue transfer surgery.

Outcome of Using Intraventricular Plus Intravenous Polymyxin B in Post-neurosurgical Patients With Multi/Extensively Drug-Resistant Gram-Negative Bacteria-Induced Intracranial Infection

Introduction

Post-neurosurgical central nervous system (CNS) infection caused by multidrug-resistant (MDR)/extensively drug-resistant (XDR) Gram-negative bacteria remains a major clinical challenge. This study describes our experience of treating such patients with combined intraventricular (IVT) and intravenous (IV) polymyxin B administration.

Methods

This retrospective study included six patients with post-neurosurgical CNS infections of carbapenem-resistant Acinetobacter baumannii (CRAB) or carbapenem-resistant Klebsiella pneumoniae (CRKP). All patients were treated in the intensive care unit (ICU) of First Affiliated Hospital, Zhejiang University School of Medicine (Hangzhou, China) between November 2020 and November 2021, and all received IVT plus IV polymyxin B. Data including patients' characteristics, therapeutic process, symptoms, cerebrospinal fluid (CSF) examination, laboratory tests, and complications were collected.

Results

Six patients with post-neurosurgical CNS infection were enrolled in the study. The patients comprised five males and one female, and the average age was 58 years (range, 38–73 years). Four out of the six cases were CRAB-positive in CSF culture, while two cases were CRKP-positive. The mean duration of polymyxin B administration was 14 ± 5.69 days (range, 6–20 days). The average period of patients reaching CSF sterilization was 10.33 ± 3.67 days (range, 5–14 days). All six cases were cured without acute kidney injury or epilepsy.

Conclusion

IVT plus IV polymyxin B is a safe and effective treatment for post-neurosurgical patients with intracranial infection caused by MDR/XDR Gram-negative bacteria.

Intrathecal Injection of Tigecycline and Polymyxin B in the Treatment of Extensively Drug-Resistant Intracranial Acinetobacter baumannii Infection: A Case Report and Review of the Literature

Purpose

Intracranial infection after neurosurgery is one of the most serious complications, especially extensively drug-resistant (XDR) Acinetobacter baumannii (A. baumannii) seriously affects the prognosis of patients. At present, there is little experience in the treatment of this infection and limited effective treatment options, like tigecycline or polymyxin B. Therefore, this report aims to describe the efficacy of tigecycline combined with polymyxin B by intrathecal (ITH) injection in the treatment of XDR intracranial infection with A. baumannii.

Methods

We report a case of intracranial infection with XDR A. baumannii after ventricular drainage, treated by daily ITH and intravenous (IV) tigecycline, combined with polymyxin B ITH route. Moreover, tigecycline and polymyxin B treatments for XDR intracranial infection with A. baumannii that were reported in the literature were also reviewed and summarized.

Results

The white blood cells (WBCs) of the patient’s cerebrospinal fluid dropped to normal, and the symptoms of intracranial infection disappeared. The patient finally obtained good clinical results and transferred to the local hospital.

Conclusion

The polymyxin B ITH route is an ideal treatment strategy for XDR A. baumannii. The IV plus ITH tigecycline may be an effective treatment option. However, more researches should be conducted to confirm our observation.

Contemporary Perspective on the Treatment of Acinetobacter baumannii Infections: Insights from the Society of Infectious Diseases Pharmacists

The purpose of this narrative review is to bring together the most recent epidemiologic, preclinical, and clinical findings to offer our perspective on best practices for managing patients with A. baumannii infections with an emphasis on carbapenem-resistant A. baumannii (CRAB). To date, the preferred treatment for CRAB infections has not been defined. Traditional agents with retained in vitro activity (aminoglycosides, polymyxins, and tetracyclines) are limited by suboptimal pharmacokinetic characteristics, emergence of resistance, and/or toxicity. Recently developed and US Food and Drug Administration (FDA)-approved β-lactam/β-lactamase inhibitor agents do not provide enhanced activity against CRAB. On balance, cefiderocol and eravacycline demonstrate potent in vitro activity and are well tolerated, but clinical data for patients with CRAB infections do not yet support widespread use. Given that CRAB has the capacity to infect vulnerable patients and preferred regimens have not been identified, we advocate for combination therapy. Our preferred regimen for critically ill patients infected, or considered to be at high risk for CRAB, includes meropenem, polymyxin B, and ampicillin/sulbactam. Importantly, site of infection, severity of illness, and local epidemiology are essential factors to be considered in selecting combination therapies. Molecular mechanisms of resistance may unveil preferred combinations at individual centers; however, such data are often unavailable to treating clinicians and have not been linked to improved clinical outcomes. Combination strategies may also pose an increased risk for antibiotic toxicity and Clostridioides difficile infection, and should therefore be balanced by understanding patient goals of care and underlying health conditions. Promising therapies that are in clinical development and/or under investigation include durlobactam-sulbactam, cefiderocol combination regimens, and bacteriophage therapy, which may over time eliminate the need for the continued use of polymyxins. Future goals for CRAB management include pathogen-focused treatment paradigms that are based on molecular mechanisms of resistance, local susceptibility rates, and the availability of well-tolerated, effective treatment options.

Synthetic Peptide Derived from Scorpion Venom Displays Minimal Toxicity and Anti-infective Activity in an Animal Model

Multidrug-resistant bacteria represent a global health problem increasingly leading to infections that are untreatable with our existing antibiotic arsenal. Therefore, it is critical to identify novel effective antimicrobials. Venoms represent an underexplored source of potential antibiotic molecules. Here, we engineered a peptide (IsCT1-NH₂) derived from the venom of the scorpion Opisthacanthus madagascariensis, whose application as an antimicrobial had been traditionally hindered by its high toxicity. Through peptide design and the knowledge obtained in preliminary studies with single and double-substituted analogs, we engineered IsCT1 derivatives with multiple amino acid substitutions to assess the impact of net charge on antimicrobial activity and toxicity. We demonstrate that increased net charge (from +3 to +6) significantly reduced toxicity toward human erythrocytes. Our lead synthetic peptide, [A]¹[K]³[F]⁵[K]⁸-IsCT1-NH₂ (net charge of +4), exhibited increased antimicrobial activity against Gram-negative and Gram-positive bacteria in vitro and enhanced anti-infective activity in a mouse model. Mechanism of action studies revealed that the increased antimicrobial activity of our lead molecule was due, at least in part, to its enhanced ability to permeabilize the outer membrane and depolarize the cytoplasmic membrane. In summary, we describe a simple method based on net charge tuning to turn highly toxic venom-derived peptides into viable therapeutics.

Clinical Features of Post-Operative Nosocomial Meningitis in Adults and Evaluation of Efficiency of Intrathecal Treatment

Background: Post-operative nosocomial meningitis is a critical complication that develops in patients after neurosurgical interventions and operations. Patients and Methods: Data were collected for 65 patients who were diagnosed as having nosocomial meningitis after neurosurgery. The agent profile, clinical and biochemical differences in gram-negative and gram-positive meningitis, and the effectiveness of intrathecal antibiotic administration in cases with carbapenem-resistant gram-negative agents were evaluated. Results: Gram-negative bacteria were isolated in 52.3% of patients. In gram-negative cases of post-operative nosocomial meningitis, white blood cell count (p = 0.015), C-reactive protein (p = 0.001), cerebrospinal fluid leukocyte count (p = 0.0001), and protein (p = 0.0001) were higher, and glucose (p = 0.002) was lower. Concurrent bacteremia (p = 0.041), 14-day mortality (p = 0.022), and 30-day mortality (p = 0.023) were higher in gram-negative cases. Empirical treatment was appropriate in 78.5% of the patients. Seventeen patients (26.2%) received intrathecal antibiotic agents in addition to intravenous antibiotic treatment because of carbapenem-resistant gram-negative bacteria. Nine (53%) of the patients receiving intrathecal therapy had Acinetobacter baumannii as the agent, six had Klebsiella pneumoniae (35.4%), one had Pseudomonas aeruginosa (5.8%), and one had Providencia rettgeri (5.8%). The mean intravenous treatment duration was 21.4 ± 10.6 (4-60) days, and the mean intrathecal treatment duration was 17.6 ± 14.0 (1-51) days. Eleven patients received colistimethate sodium intrathecally (1 × 10 mg/d), three patients received amikacin intrathecally (1 × 10 mg/d), and three patients received gentamicin intrathecally (1 × 10 mg/d). Clinical and microbiologic treatment success was achieved in nine patients (53%). Conclusions: In cases of meningitis caused by carbapenem-resistant agents, intrathecal administration of antibiotic agents such as gentamicin, amikacin, and colistin with limited blood-brain barrier transition in intravenous administration will increase survival. Therefore, intrathecal antibiotic administration should be considered as a part of routine of nosocomial meningitis.

Acinetobacter baumannii strains isolated from cerebrospinal fluid (CSF) and bloodstream analysed by cgMLST: the dominance of clonal complex CC92 in CSF infections

A total of 54 unique clinical Acinetobacter baumannii strains isolated from cerebrospinal fluid (CSF) together with 21 bloodstream isolates collected from five tertiary hospitals in East China between April 2013 and November 2016 were studied for antimicrobial susceptibility patterns and the prevalence of antimicrobial resistance genes. Molecular epidemiological characteristics of CSF isolates and the phylogenetic relationship of isolates from different sources were assessed using multilocus sequence typing (MLST) and core genome MLST (cgMLST). Of the 54 CSF isolates, 51 (94.4%) were bla_OXA-23-carrying carbapenem-resistant A. baumannii. Their average resistance rate to different classes of antibiotics was extremely high (>90%), except for tigecycline and colistin. According to the Oxford MLST scheme, all CSF isolates fell into 10 defined sequence types (STs) and 4 novel STs. ST195 and ST208 were the leading STs in isolates from either source. A total of 50 CSF isolates and 20 bloodstream isolates were assigned to clonal complex 92 (CC92), revealing a wild distribution of CC92 in the hospitals of East China. In combination with epidemiological data linked in time and space, cgMLST results elucidated intrahospital and interhospital polyclonal dissemination of A. baumannii causing meningitis. Based on cgMLST, there was no correlation between phylogeny and the source of isolation of A. baumannii. These results emphasise that the genetic potential of this pathogen is vast enough to infect multiple human body sites.

Campylobacter fetus bacteremia and meningitis in an acute lymphoblastic leukemia patient undergoing maintenance therapy: a case report

BACKGROUND

Campylobacter fetus is an uncommon Campylobacter species, and its infections mainly cause infective endocarditis, aortic aneurysm, and meningitis rather than enteritis. It is more likely to be detected in blood than Campylobacter jejuni or Campylobacter coli, specifically reported in 53% of patients. In our case, C. fetus was detected in both blood and cerebrospinal fluid (CSF) cultures.

CASE PRESENTATION

A 33-year-old woman, who was on maintenance chemotherapy for acute lymphoblastic leukemia (ALL), presented to our clinic with chief complaints of severe headache and nausea. Blood and CSF cultures revealed C. fetus. We administrated meropenem 2 g intravenously (IV) every 8 h for 3 weeks, and she was discharged without neurological sequelae.

CONCLUSION

We encountered a case of C. fetus meningitis without gastrointestinal symptoms, neck stiffness or jolt accentuation in a patient with ALL. Undercooked beef was considered the source of C. fetus infection in this case, suggesting that the need for a neutropenic diet and safe food handling be considered.

Gram-Negative Ventriculostomy-Associated Infections Predict Shunt Dependency in Stroke Diagnoses and Other Brain Injuries

BACKGROUND

Several predictors have been studied for shunt dependency after stroke and other brain injuries. However, little is known about the association between ventriculostomy-associated infections (VAIs) and impaired cerebrospinal fluid (CSF) outflow. Moreover, gram-negative (GN) VAIs induce a potent neuroinflammatory process and are clinically challenging to treat.

OBJECTIVE

To assess if GN-VAIs predict ventriculoperitoneal shunt (VPS) dependency.

METHODS

Retrospective analysis of postprocedure infection rates was performed in 586 patients with external ventricle drainage (EVD) placed on site between 2012 and 2018. We collected sex, age, stroke and nonstroke related, location of EVD placement, type of hospital, EVD duration, and EVD exchange.

RESULTS

Among 586 patients requiring an EVD, 55 developed a VAI. Most were caused by gram-positive (GP) pathogens (61.8%). A total of 120 patients required a conversion from EVD to VPS. Patients with VAIs had higher rates of VPS placement (49.09% vs 17.65%, P < .001), whereas patients with GN-VAIs had significantly higher rates of EVD conversion to VPS (77.78% vs 35.29%, P = .012) compared with GP-VAIs. The multivariate analysis showed that GN-VAIs were an independent predictor for shunt dependency (odds ratio = 12.896; 95% CI 3.407-48.82, P < .001). In receiver operating characteristics analysis, those less than 44.5 yr of age and more than 12 d of EVD duration were identified as the best cutoff values to discriminate the development of GN-VAI.

CONCLUSION

Patients who experience a GN VAI are in greater risk of impaired CSF outflow, thus requiring VPS placement.

Acinetobacter baumannii Infections in Hospitalized Patients, Treatment Outcomes

Background Acinetobacter baumannii (AB), an opportunistic pathogen, could develop into serious infections with high mortality and financial burden. The debate surrounding the selection of effective antibiotic treatment necessitates studies to define the optimal approach. This study aims to compare the clinical outcomes of commonly used treatment regimens in hospitalized patients with AB infections to guide stewardship efforts. Material and methods: Ethical approval was obtained, 320 adult patients with confirmed AB infections admitted to our tertiary care facility within two years were enrolled. The treatment outcomes were statistically analyzed to study the relation between antibiotic regimens and 14, 28, and 90-day mortality as the primary outcomes using binary logistic regression—using R software—in addition to the length of hospitalization, adverse events due to antibiotic treatment, and 90-day recurrence as secondary outcomes. Results: Among 320 patients, 142 (44%) had respiratory tract, 105 (33%) soft tissue, 42 (13%) urinary tract, 22 (7%) bacte iemia, and other infections 9 (3%). Nosocomial infections were 190 (59%) versus community-acquired. Monotherapy was significantly associated with lower 28-day (p < 0.05, OR:0.6] and 90-day (p < 0.05, OR:0.4) mortality rates, shorter length of stay LOS (p < 0.05, Median: −12 days] and limited development of adverse events (p < 0.05, OR:0.4). Subgroup analysis revealed similar results ranging from lower odds of mortality, adverse events, and shorter LOS to statistically significant correlation to monotherapy. Meropenem (MEM) and piperacillin/tazobactam (PIP/TAZ) monotherapies showed non-significant high odd ratios of mortalities, adverse events, and disparate LOS. There was a statistical correlation between most combined therapies and adverse events, and longer LOS. Colistin based and colistin/meropenem (CST/MEM) combinations were superior in terms of 14-day mortality (p = 0.05, OR:0.4) and (p < 0.05, OR:0.4) respectively. Pip/Taz and MEM-based combined therapies were associated with statistically non-significant high odd ratios of mortalities. Tigecycline (TGC)-based combinations showed a significant correlation to mortalities (p < 0.05, OR:2.5). Conclusion: Monotherapy was associated with lower mortality rates, shorter LOS, and limited development of adverse events compared to combined therapies. Colistin monotherapy, colistin/meropenem, and other colistin combinations showed almost equivalent mortality outcomes. Patients on combined therapy were more susceptible to adverse events and comparable LOS. The possible adverse outcomes of PIP/TAZ and MEM-based therapies in the treatment of MDRAB infections and the association of TGC with a higher mortality rate raise doubts about their treatment role.

Central nervous system infections and antimicrobial resistance: an evolving challenge

PURPOSE OF REVIEW

Antimicrobial resistance is an increasing threat to patients also in nosocomial central nervous system (CNS) infections. The present review focusses on optimizing intravenous treatment in order to achieve sufficient concentrations of antibiotics in the different compartments of the CNS when the causative pathogens have reduced sensitivity to antibiotics or/and the impairment of the blood-cerebrospinal fluid (CSF) and blood-brain barrier is mild.

RECENT FINDINGS

Experience has been gathered with treatment protocols for several established antibiotics using increased doses or continuous instead of intermittent intravenous therapy. Continuous infusion in general does not increase the average CSF concentrations (or the area under the concentration-time curve in CSF) compared to equal daily doses administered by short-term infusion. In some cases, it is postulated that it can reduce toxicity caused by high peak plasma concentrations. In case reports, new β-lactam/β-lactamase inhibitor combinations were shown to be effective treatments of CNS infections.

SUMMARY

Several antibiotics with a low to moderate toxicity (in particular, β-lactam antibiotics, fosfomycin, trimethoprim-sulfamethoxazole, rifampicin, vancomycin) can be administered at increased doses compared to traditional dosing with low or tolerable adverse effects. Intrathecal administration of antibiotics is only indicated, when multiresistant pathogens cannot be eliminated by systemic therapy. Intravenous should always accompany intrathecal treatment.

A hospital-based study on etiology and prognosis of bacterial meningitis in adults

Bacterial meningitis is a neurological emergency with high morbidity and mortality. We herein investigated clinical features, etiology, antimicrobial susceptibility profiles, and prognosis of bacterial meningitis in adults from a single tertiary center. We retrospectively reviewed medical records of patients with laboratory-confirmed bacterial meningitis from 2007 to 2016. Patients with recent neurosurgery, head trauma, or indwelling neurosurgical devices were classified as having healthcare-related meningitis. Causative microorganisms were identified by analyzing cerebrospinal fluid (CSF) and blood cultures, and antimicrobial susceptibility profiles were evaluated. We performed multiple logistic regression analysis to identify factors associated with unfavorable outcomes. We identified 161 cases (age, 55.9 ± 15.5 years; male, 50.9%), of which 43 had community-acquired and 118 had healthcare-related meningitis. CSF and blood culture positivity rates were 91.3% and 30.4%, respectively. In community-acquired meningitis patients, Klebsiella pneumoniae (25.6%) was the most common isolate, followed by Streptococcus pneumoniae (18.6%) and Listeria monocytogenes (11.6%). The susceptibility rates of K. pneumoniae to ceftriaxone, cefepime, and meropenem were 85.7%, 81.3%, and 100%, respectively. Among healthcare-related meningitis patients, the most common bacterial isolates were coagulase-negative staphylococci (28.0%), followed by Staphylococcus aureus (16.1%) and Enterobacter spp. (13.6%). Neurological complications occurred in 39.1% of the patients and the 3-month mortality rate was 14.8%. After adjusting for covariates, unfavorable outcome was significantly associated with old age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.00–1.06), neurological complications (OR 4.53, 95% CI 1.57–13.05), and initial Glasgow coma scale ≤ 8 (OR 19.71, 95% CI 4.35–89.40). Understanding bacterial pathogens and their antibiotic susceptibility may help optimize antimicrobial therapy in adult bacterial meningitis.

Successful treatment of pyogenic ventriculitis caused by extensively drug-resistant Acinetobacter baumannii with multi-route tigecycline: A case report

BACKGROUND

Pyogenic ventriculitis caused by extensively drug-resistant Acinetobacter baumannii (A. baumannii) is one of the most severe complications associated with craniotomy. However, limited therapeutic options exist for the treatment of A. baumannii ventriculitis due to the poor penetration rate of most antibiotics through the blood-brain barrier.

CASE SUMMARY

A 68-year-old male patient with severe traumatic brain injury developed pyogenic ventriculitis on postoperative day 24 caused by extensively drug-resistant A. baumannii susceptible to tigecycline only. Successful treatment was accomplished through multi-route administration of tigecycline, including intravenous combined with continuous ventricular irrigation plus intraventricular administration. The pus was cleared on the 3^rd day post-irrigation, and cerebrospinal fluid cultures were negative after 12 d.

CONCLUSION

Our findings suggest that multi-route administration of tigecycline can be a therapeutic option against pyogenic ventriculitis caused by extensively drug-resistant A. baumannii.

Detection of multidrug resistant environmental isolates of acinetobacter and Stenotrophomonas maltophilia: a possible threat for community acquired infections?

Acinetobacter spp. and Stenotrophomonas maltophilia are bacteria commonly associated with infections at the clinical settings. Reports of infections caused by environmental isolates are rare. Therefore, this study focused on determination of the antibiotic resistance patterns, antibiotic resistance genes, efflux pumps and virulence signatures of Acinetobacter spp. and S. maltophilia recovered from river water, plant rhizosphere and river sediment samples. The isolates were identified and confirmed using biochemical tests and PCR. The antimicrobial resistance profiles of the isolates were determined using Kirby Bauer disk diffusion assay and presence of antibiotic resistance and virulence genes were detected using PCR. S. maltophilia was more frequent in plant rhizosphere and sediment samples than the water samples. Acinetobacter spp. were mostly resistant to trimethoprim-sulfamethoxazole (96% of isolates), followed by polymyxin b (86%), cefixime (54%), colistin (42%), ampicillin (35%) and meropenem (19%). The S. maltophilia isolates displayed total resistance (100%) to trimethoprim- sulfamethoxazole, meropenem, imipenem, ampicillin and cefixime, while 80% of the isolates were resistant to ceftazidime. Acinetobacter spp. contained different antibiotic resistance genes such as sul1 (24% of isolates), sul2 (29%), blaOXA 23/51 (21%) and blaTEM (29%), while S. maltophilia harbored sul1 (8%) and blaTEM (20%). Additionally, efflux pump genes were present in all S. maltophilia isolates. The presence of multidrug resistant Acinetobacter spp. and Stenotrophomonas maltophilia in surface water raises concerns for community-acquired infections as this water is directly been used by the community for various purposes. Therefore, there is the need to institute measures aimed at reducing the risks of these infections and the resulting burden this may have on the health care system within the study area.

Outcome following postneurosurgical Acinetobacter meningitis: an institutional experience of 72 cases

OBJECTIVE

The authors aimed to evaluate the antimicrobial susceptibility pattern of Acinetobacter isolates responsible for nosocomial meningitis/ventriculitis in the neurosurgical ICU. The authors also sought to identify the risk factors for mortality following Acinetobacter meningitis/ventriculitis.

METHODS

This was a retrospective study of 72 patients admitted to the neurosurgical ICU between January 2014 and December 2018 with clinical and microbiological diagnosis of nosocomial postneurosurgical Acinetobacter baumanii meningitis/ventriculitis. Electronic medical data on clinical characteristics, underlying pathology, CSF cytology, antibiotic susceptibilities, and mortality were recorded. To evaluate the outcome following nosocomial postneurosurgical Acinetobacter meningitis/ventriculitis, patients were followed up until discharge or death in the hospital. Kaplan-Meier survival analysis and multivariable Cox proportional hazards models were used to compute factors affecting survival.

RESULTS

The study population was divided into two groups depending on the final outcome of whether the patient died or survived. Forty-three patients (59.7%) were included in the survivor group and 29 patients (40.3%) were included in the nonsurvivor group. Total in-hospital mortality due to Acinetobacter meningitis/ventriculitis was 40.3% (29 cases), with a 14-day mortality of 15.3% and a 30-day mortality of 25%. The 43 (59.7%) patients who survived had a mean length of hospital stay of 44 ± 4 days with a median Glasgow Outcome Scale-Extended score at discharge of 6. On univariate analysis, age > 40 years (p = 0.078), admission Glasgow Coma Scale (GCS) score ≤ 8 (p = 0.003), presence of septic shock (p = 0.011), presence of external ventricular drain (EVD) (p = 0.03), CSF white blood cell (WBC) count > 200 cells/mm3 (p = 0.084), and comorbidities (diabetes, p = 0.036; hypertension, p = 0.01) were associated with poor outcome. Carbapenem resistance was not a risk factor for mortality. According to a multivariable Cox proportional hazards model, age cutoff of 40 years (p = 0.016, HR 3.21), GCS score cutoff of 8 (p = 0.006, HR 0.29), CSF WBC count > 200 cells/mm3 (p = 0.01, HR 2.76), presence of EVD (p = 0.001, HR 5.42), and comorbidities (p = 0.017, HR 2.8) were found to be significant risk factors for mortality.

CONCLUSIONS

This study is the largest case series reported to date of postneurosurgical Acinetobacter meningitis/ventriculitis. In-hospital mortality due to Acinetobacter meningitis/ventriculitis was high. Age older than 40 years, GCS score less than 8, presence of EVD, raised CSF WBC count, and presence of comorbidities were risk factors for mortality.

Successful Management of Pan-Resistant Acinetobacter baumannii Meningitis without Intrathecal or Intraventricular Antibiotic Therapy in a Neonate

Acinetobacter baumannii is one of the most important etiologies of nosocomial infections in recent years mainly because of increasing in frequency of multidrug and pan-resistant pathogens. Meningitis caused by this organism is a dilemma; because polymyxins are the only effective antibiotics against pan-resistant serotypes, but have poor penetration via blood brain barrier; however, it has still remained uncertain whether the intravenous therapy with these agents is an effective treatment with the sufficient concentration of the drug in the cerebrospinal fluid. Herein, we report a neonate who suffered from pan-resistant A. baumannii nosocomial meningitis successfully treated with intravenous colistin combined with meropenem and rifampin. It seems that intravenous colistin at least in combination with rifampin and meropenem might be considered as an option to try in patients in whom daily intrathecal injection or insertion of intraventricular device is not possible.

A Clinical Study on the Use of Intraventricular Polymyxin B Supplemented by Continuous External Ventricular Drainage in the Treatment of Drug-Resistant Gram-Negative Bacilli Intracranial Infection

Purpose

To investigate the clinical effect of ventricular polymyxin B supplemented by continuous external ventricular drainage in the treatment of intracranial infection with multidrug-resistant (MDR) or extensively drug-resistant (XDR) Gram-negative (G-) bacilli following neurosurgery.

Patients and Methods

A retrospective analysis was performed on 28 patients who had G-bacilli intracranial infection following neurosurgery in our department between January 2017 and December 2019. The patients were treated with intraventricular polymyxin B supplemented by continuous external ventricular drainage. The clinical characteristics, treatment process, cerebrospinal-fluid-related indicators, results and prognosis were analysed.

Results

All of 28 patients developed an infection subsequent to neurosurgery, and cerebrospinal fluid (CSF) cultures demonstrated MDR/XDR G- bacilli, including Acinetobacter baumannii in 14 cases, Klebsiella pneumoniae in 9 cases, Pseudomonas aeruginosa in 3 cases, and Enterobacter cloacae in 2 cases. The ventricular drainage tube remained unobstructed in all patients during treatment, and intraventricular polymyxin B combined with intravenous antibiotics were administered each day. The duration of treatment with intraventricular polymyxin B was 14.96±4.28 days, and the time required to obtain a negative CSF culture was 8.23±4.02 days. The bacterial clearance rate from cerebrospinal fluid was 92.9% (26/28), and the clinical cure rate was 82.1% (23/28). Among them, 18 patients underwent ventriculoperitoneal shunt insertion for hydrocephalus 82.5 (59.5,114.75) days after the infection was cured, and the mortality rate was 17.6% (5/28). There was no significant change in patient blood creatinine levels before and after treatment. Cured patients were followed up for 4 months to 3 years, and no recurrences were observed.

Conclusion

Treatment of intracranial infection with MDR/XDR G- bacilli using early intraventricular polymyxin B supplemented by continuous external ventricular drainage treatment may be a safe and effective treatment strategy.

Development and Validation of a Model for Predicting the Risk of Death in Patients with Acinetobacter baumannii Infection: A Retrospective Study

Purpose

This study aimed to develop and validate a personalized prediction model of death risk in patients with Acinetobacter baumannii (A. baumannii) infection and thus guide clinical research and support clinical decision-making.

Patients and Methods

The development group is comprised of 350 patients with A. baumannii infection admitted between January 2013 and December 2015 in The First Affiliated Hospital of Anhui Medical University. Further, 272 patients in the validation group were admitted between January 2016 and December 2018. The univariate and multivariate logistic regression analyses were used to determine the independent risk factors for death with A. baumannii infection. The nomogram prediction model was established based on the regression coefficients. The discrimination of the proposed prediction model was evaluated using the area under the curve (AUC) of the receiver operating characteristic (ROC) curves and decision curve analysis (DCA). The calibration diagram was used to evaluate the calibration degree of this model.

Results

The infectious source, carbapenem-resistant A. baumannii (CRAB), hypoalbuminemia, Charlson comorbidity index (CCI), and mechanical ventilation (MV) were independent risk factors for death. The AUC of the ROC curve of the two groups was 0.768 and 0.792, respectively. The net income was higher when the probability was between 30% and 80%, showing a strong discrimination capacity of the proposed model. The calibration curve swung around the 45° oblique line, indicating a high degree of calibration.

Conclusion

The proposed model helped predict the risk of death from A. baumannii infection, improve the early identification of patients with a higher risk of death, and guide clinical treatment.

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An external ventricular drainage catheter impregnated with rifampicin, trimethoprim and triclosan, with extended activity against MDR Gram-negative bacteria: an in vitro and in vivo study

Background

External ventricular drainage (EVD) carries a high risk of ventriculitis, increasingly caused by MDR Gram-negative bacteria such as Escherichia coli and Acinetobacter baumannii. Existing antimicrobial EVD catheters are not effective against these, and we have developed a catheter with activity against MDR bacteria and demonstrated the safety of the new formulation for use in the brain.

Objectives

Our aim was to determine the ability of a newly formulated impregnated EVD catheters to withstand challenge with MDR Gram-negative bacteria and to obtain information about its safety for use in the CNS.

Methods

Catheters impregnated with three antimicrobials (rifampicin, trimethoprim and triclosan) were challenged in flow conditions at four weekly timepoints with high doses of MDR bacteria, including MRSA and Acinetobacter, and monitored for bacterial colonization. Catheter segments were also inserted intracerebrally into Wistar rats, which were monitored for clinical and behavioural change, and weight loss. Brains were removed after either 1 week or 4 weeks, and examined for evidence of inflammation and toxicity.

Results

Control catheters colonized quickly after the first challenge, while no colonization occurred in the impregnated catheters even after the 4 week challenge. Animals receiving the antimicrobial segments behaved normally and gained weight as expected. Neurohistochemistry revealed only surgical trauma and no evidence of neurotoxicity.

Conclusions

The antimicrobial catheter appears to withstand bacterial challenge for at least 4 weeks, suggesting that it might offer protection against infection with MDR Gram-negative bacteria in patients undergoing EVD. It also appears to be safe for use in the CNS.

Spinal arachnoiditis followed by intrathecal tigecycline therapy for central nervous system infection by extremely drug-resistant Acinetobacter baumannii

In prior research, intrathecal tigecycline was successfully used to treat central nervous system infection by extensively drug-resistant Acinetobacter baumannii. However, little is known about its safe dose and adverse reactions. This study reports the case of a 28-year-old male patient who was diagnosed with central nervous system infection by extensively drug-resistant A. baumannii after the removal of a ventriculoperitoneal shunt. Intravenous and intrathecal tigecycline were administrated simultaneously. Spinal arachnoiditis was discovered after nine doses of intrathecal tigecycline. Spinal arachnoiditis was resolved after discontinuation of the antibiotic. This is the first report of an adverse reaction to intrathecal tigecycline. The case was complicated by spinal arachnoiditis, which obstructed the assessment of cerebrospinal fluid. The appropriate dose and administration schedule of intrathecal tigecycline remain to be determined.

Antimicrobial Resistance in ESKAPE Pathogens

Antimicrobial-resistant ESKAPE ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens represent a global threat to human health. The acquisition of antimicrobial resistance genes by ESKAPE pathogens has reduced the treatment options for serious infections, increased the burden of disease, and increased death rates due to treatment failure and requires a coordinated global response for antimicrobial resistance surveillance. This looming health threat has restimulated interest in the development of new antimicrobial therapies, has demanded the need for better patient care, and has facilitated heightened governance over stewardship practices.

Antimicrobial Resistance in ESKAPE Pathogens

Antimicrobial-resistant ESKAPE ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens represent a global threat to human health. The acquisition of antimicrobial resistance genes by ESKAPE pathogens has reduced the treatment options for serious infections, increased the burden of disease, and increased death rates due to treatment failure and requires a coordinated global response for antimicrobial resistance surveillance. This looming health threat has restimulated interest in the development of new antimicrobial therapies, has demanded the need for better patient care, and has facilitated heightened governance over stewardship practices.

Impact of an educational program on reducing health care-associated meningitis or ventriculitis in the neurosurgical intensive care unit

BACKGROUND

Health care-associated meningitis or ventriculitis (HCAMV) is a serious complication in different neurosurgical procedures and is associated with significant morbidity and mortality. We aimed to investigate whether an educational intervention program could reduce the HCAMV incidence in patients undergoing postsurgery external ventricular drainage and wound management.

METHODS

We enrolled 2,904 patients from the neurosurgery intensive care unit between January 1, 2016 and December 31, 2018. The medical staff undertook an educational program developed by a multidisciplinary team on correct external ventricular drainage insertion and maintenance. The program included a 9-page self-learning module on the HCAMV risk factors and operational improvements. Each participant completed a pre- and posttest on their HCAMV knowledge.

RESULTS

We found that 38 of 693 (5.48%) patients presented with infection in the preintervention 9-month period. In the 27-month postintervention period, the proportion of HCAMV incidence dropped by 52.19% (P < .0001) to 58 of 2,211 (2.62%) patients.

CONCLUSIONS

Educational intervention aimed at the neurosurgery intensive care unit staff could significantly reduce the HCAMV rate, leading to a significant decline in the cost, morbidity, and mortality caused by neurosurgical procedures.

Sequential intraventricular injection of tigecycline and polymyxin B in the treatment of intracranial Acinetobacter baumannii infection after trauma: a case report and review of the literature

BACKGROUND

Intracranial infection after craniotomy is one of the most serious postoperative complications, especially multidrug-resistant (MDR) or extensively drug-resistant (XDR) bacterial meningitis, and strongly affects the prognosis of patients. Current treatment experience regarding these infections is scarce.

CASE PRESENTATION

We report a case of severe intracranial infection of XDR Acinetobacter baumannii (A. baumannii) that was treated by intravenous (IV) injection, sequential intraventricular (IVT) injection of tigecycline and polymyxin B, and other anti-infective drugs. Good results were obtained, and the patient was eventually discharged from the hospital. This case is characterized by intracranial infection.

CONCLUSIONS

The polymyxin B IV + IVT pathway is an ideal treatment strategy for XDR A. baumannii. The tigecycline IVT pathway is also a safe treatment option.

Prevalence of Bacterial Contamination of Casting Material in a Pediatric Population

Surgical site infection is a relatively common and devastating complication following pediatric orthopedic surgery. Many infections have been determined to be the result of settled airborne particles on surgical equipment and the sterile field. Fiberglass casts are commonly used orthopedic fixation devices before and after surgery; however, fiberglass casting material is expelled during the removal process and represents an uninvestigated area for the possibility of cast saw dust as a source of airborne bacterial contamination in an operating room setting. This study evaluates the prevalence and distribution of microbiota on 90 pediatric casts by collecting and culturing fiberglass cast material from 90 pediatric casts. Bacterial identification was performed using a Bruker Biotyper Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry device. 81 out of 90 casts (90%) showed evidence of microbial contamination. Isolated species were very diverse and ranged from normal skin flora to opportunistic pathogens. The 5 most commonly isolated organisms were Acinetobacter pittii, Enterobacter cloacae, Micrococcus luteus, Staphylococcus epidermidis, and Staphylococcus hominis. Further investigation is required to determine if casting material is truly a cause of surgical site infection.

International Consensus Guidelines for the Optimal Use of the Polymyxins: Endorsed by the American College of Clinical Pharmacy (ACCP), European Society of Clinical Microbiology and Infectious Diseases (ESCMID), Infectious Diseases Society of America (IDSA), International Society for Anti-infective Pharmacology (ISAP), Society of Critical Care Medicine (SCCM), and Society of Infectious Diseases Pharmacists (SIDP)

The polymyxin antibiotics colistin (polymyxin E) and polymyxin B became available in the 1950s and thus did not undergo contemporary drug development procedures. Their clinical use has recently resurged, assuming an important role as salvage therapy for otherwise untreatable gram-negative infections. Since their reintroduction into the clinic, significant confusion remains due to the existence of several different conventions used to describe doses of the polymyxins, differences in their formulations, outdated product information, and uncertainties about susceptibility testing that has led to lack of clarity on how to optimally utilize and dose colistin and polymyxin B. We report consensus therapeutic guidelines for agent selection and dosing of the polymyxin antibiotics for optimal use in adult patients, as endorsed by the American College of Clinical Pharmacy (ACCP), Infectious Diseases Society of America (IDSA), International Society of Anti-Infective Pharmacology (ISAP), Society for Critical Care Medicine (SCCM), and Society of Infectious Diseases Pharmacists (SIDP). The European Society for Clinical Microbiology and Infectious Diseases (ESCMID) endorses this document as a consensus statement. The overall conclusions in the document are endorsed by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). We established a diverse international expert panel to make therapeutic recommendations regarding the pharmacokinetic and pharmacodynamic properties of the drugs and pharmacokinetic targets, polymyxin agent selection, dosing, dosage adjustment and monitoring of colistin and polymyxin B, use of polymyxin-based combination therapy, intrathecal therapy, inhalation therapy, toxicity, and prevention of renal failure. The treatment guidelines provide the first ever consensus recommendations for colistin and polymyxin B therapy that are intended to guide optimal clinical use.

Postoperative multidrug-resistant Acinetobacter baumannii meningitis successfully treated with intravenous doxycycline and intraventricular gentamicin: A case report

BACKGROUND

Multidrug-resistant Acinetobacter baumannii (MDRAB) has emerged as an increasingly important pathogen that causes nosocomial meningitis. However, MDRAB-associated nosocomial meningitis is rarely reported in children.

CASE SUMMARY

We report the case of a 1-year-old girl with a choroid plexus papilloma, who developed postoperative nosocomial meningitis due to MDRAB. The bacterial strain was sensitive only to tigecycline and colistin, and showed varying degrees of resistance to penicillin, amikacin, ceftriaxone, cefixime, cefotaxime, ciprofloxacin, levofloxacin, gentamicin, meropenem, imipenem, and tobramycin. She was cured with intravenous doxycycline and intraventricular gentamicin treatment.

CONCLUSION

Doxycycline and gentamicin were shown to be effective and safe in the treatment of a pediatric case of MDRAB meningitis.

Prevención y tratamiento de las infecciones del sitio operatorio en neurocirugía. Estado del arte

El manejo adecuado de las infecciones del sitio operatorio (ISO) en neurocirugía es fundamental para la disminución de la carga de morbilidad y mortalidad en estos pacientes. La sospecha y confirmación diagnóstica asociadas al aislamiento microbiológico son esenciales para asegurar el tratamiento oportuno y el adecuado gerenciamiento de antibióticos. En esta revisión se presenta de forma resumida los puntos fundamentales para la prevención y el tratamiento de infecciones del sitio operatorio en neurocirugía y se incluye un apartado sobre el uso de antibióticos intratecales/intraventriculares.

Intrathecal or intraventricular antimicrobial therapy for post-neurosurgical intracranial infection due to multidrug-resistant and extensively drug-resistant Gram-negative bacteria: A systematic review and meta-analysis

This review investigated the effectiveness and safety of intrathecal (ITH) or intraventricular (IVT) antimicrobial therapy for post-neurosurgical intracranial infection due to multidrug-resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacteria. Electronic databases including PubMed, EMBASE and the Cochrane Library databases were searched for clinical studies that compared the addition of ITH/IVT therapy with intravenous (IV) monotherapy in the treatment of post-neurosurgical intracranial infection due to MDR/XDR Gram-negative bacteria. Eligible articles were analysed using Stata/SE software v.12.0. Publication bias was assessed using Begg's funnel plot and Egger's test. Nine studies involving 296 patients were included. The odds ratio (OR) for death (IV+ITH/IVT versus IV) reported in the included studies ranged from 0.02-0.93. The overall pooled OR was 0.15 [95% confidence interval (CI) 0.08-0.28; P < 0.001] and the risk of mortality was significantly different between the two groups. Microbiological clearance was significantly different between the two groups, with a pooled OR of 0.02 (95% CI 0.01-0.10; P < 0.001). In observational studies, addition of ITH/IVT antimicrobial therapy is associated with a lower risk of mortality and a higher microbiological clearance rate, with mild adverse effects, in patients with post-neurosurgical intracranial infection due to MDR/XDR Gram-negative bacteria. A well-designed randomised controlled trial is necessary to address this important issue.

Epidemiology and Treatment of Multidrug-Resistant and Extensively Drug-Resistant Pseudomonas aeruginosa Infections

In recent years, the worldwide spread of the so-called high-risk clones of multidrug-resistant or extensively drug-resistant (MDR/XDR) Pseudomonas aeruginosa has become a public health threat. This article reviews their mechanisms of resistance, epidemiology, and clinical impact and current and upcoming therapeutic options. In vitro and in vivo treatment studies and pharmacokinetic and pharmacodynamic (PK/PD) models are discussed. Polymyxins are reviewed as an important therapeutic option, outlining dosage, pharmacokinetics and pharmacodynamics, and their clinical efficacy against MDR/XDR P. aeruginosa infections. Their narrow therapeutic window and potential for combination therapy are also discussed. Other "old" antimicrobials, such as certain β-lactams, aminoglycosides, and fosfomycin, are reviewed here. New antipseudomonals, as well as those in the pipeline, are also reviewed. Ceftolozane-tazobactam has clinical activity against a significant percentage of MDR/XDR P. aeruginosa strains, and its microbiological and clinical data, as well as recommendations for improving its use against these bacteria, are described, as are those for ceftazidime-avibactam, which has better activity against MDR/XDR P. aeruginosa, especially strains with certain specific mechanisms of resistance. A section is devoted to reviewing upcoming active drugs such as imipenem-relebactam, cefepime-zidebactam, cefiderocol, and murepavadin. Finally, other therapeutic strategies, such as use of vaccines, antibodies, bacteriocins, anti-quorum sensing, and bacteriophages, are described as future options.

A case report of intraventricular and intrathecal tigecycline infusions for an extensively drug-resistant intracranial Acinetobacter baumannii infection

RATIONALE

The treatment of intracranial Acinetobacter baumannii infections is made difficult by multidrug-resistance poor drug penetration through the blood-brain barrier (BBB). Although tigecycline appears to be effective against A baumannii, it is only administered intravenously because it does not readily cross the BBB. The addition of intraventricular (IVT) or intrathecal infusions of tigecycline could revolutionize clinical therapy for intracranial A baumannii infections. However, there are few reports on the successful use of such treatments.

PATIENT CONCERNS

We report the case of a 17-year-old male who presented with high fever and neck rigidity after intracranial drainage.

DIAGNOSIS

Intracranial infection with extensively drug-resistant A baumannii after intracranial drainage.

INTERVENTIONS

On the advice of a clinical pharmacist, the patient was administered intrathecal infusions of tigecycline after treatment failure with IVT tigecycline.

OUTCOMES

The patient's body temperature returned to normal. Thereafter, the patient was in good clinical condition without signs of cerebrospinal fluid infection and tuberculosis.

LESSONS

However, when central nervous system infections fail IVT tigecycline, clinicians should consider changing to intrathecal tigecycline infusions rather than raising the dose of IVT tigecycline. In addition, the co-administration of tigecycline with other drugs that can penetrate the BBB should not be ruled out.

Combination Treatment with Intravenous Tigecycline and Intraventricular and Intravenous Colistin in Postoperative Ventriculitis Caused by Multidrug-resistant Acinetobacter baumannii

Nosocomial infections with multidrug-resistant (MDR) pathogens are a life-threatening complication in neurosurgery. An MDR Acinetobacter baumannii (A. baumannii) central nervous system (CNS) infection following neurosurgery has been previously reported and was treated with relative success using intraventricular and/or intravenous (IV) colistin, IV tigecycline, or IV colistin-rifampicin combination therapy. We present a case of MDR A. baumannii in a 13-year-old girl following parietal craniotomy for the resection of a right intraventricular meningioma. Several days after surgery, the patient presented with clinical, radiological, laboratorial, and microbiological evidence of carbapenem-resistant A. baumannii ventriculitis. She was treated with IV colistin and then with combined intraventricular-IV colistin, with partial failure. The combined treatment of IV tigecycline and associated intraventricular and intravenous colistin was started and significant improvement was seen clinically and radiologically, with negative cultures after one week. To the best of our knowledge, this is the first case of a successful combination of intraventricular and IV colistin combined with IV tigecycline after a partial treatment failure with intraventricular and IV colistin alone.