Microbiology, chemotherapy and mortality of brain abscess in Newcastle-upon-Tyne between 1979 and 1988

Central nervous system abscesses and empyemas in England: epidemiological trends over five decades

OBJECTIVES

To report on population-based epidemiological trends in central nervous system (CNS) abscesses and empyemas in England over five decades.

METHODS

Trend analyses of age-sex-specific hospital admission and death rates using routinely collected English national hospital discharge records, mortality records, and annual population denominators from 1968 to 2019.

RESULTS

Hospital admission rates for CNS abscesses and empyemas were stable in England until the late 1980s. In the last two decades of the study period (1999-2019), first-time admissions increased from 1.24 per 100,000 population in 1999 (95% confidence interval [CI] 1.14-1.35) to 2.86 in 2019 (95% CI 2.72-3.01). Admission rates were highest among infants and older adults, and were higher for males than females. There were small but significant increases in annual mortality rates for CNS abscesses and empyemas over the last two decades of the study period after accounting for population ageing, but mortality remained low at around 0.1-0.2 per 100,000 population. Mortality increased with advancing age; deaths in childhood were extremely rare. Case fatality rates where a relevant diagnosis was recorded as either the underlying or contributing cause were 4.3% and 9.7% respectively.

CONCLUSIONS

The increase in CNS abscesses and empyemas in England might reflect improved case ascertainment, but the likelihood of a true rise in incidence should be considered.

Pyogenic brain abscess and subdural empyema: presentation, management, and factors predicting outcome

PURPOSE

To describe the presentation and management of bacterial brain abscess and subdural empyema in adults treated at two tertiary centers. In addition, to identify factors that may predict a poor clinical outcome.

METHODS

A retrospective analysis of data obtained from clinical records was performed, followed by multivariate regression analysis of patient and treatment-related factors.

RESULTS

113 patients were included with a median age of 53 years and a male preponderance. At presentation symptoms were variable, 28% had a focal neurological deficit, and 39% had a reduced Glasgow coma scale (GCS). Brain abscesses most frequently affected the frontal, temporal, and parietal lobes while 36% had a subdural empyema. An underlying cause was identified in 76%; a contiguous ear or sinus infection (43%), recent surgery or trauma (18%) and haematogenous spread (15%). A microbiological diagnosis was confirmed in 86%, with streptococci, staphylococci, and anaerobes most frequently isolated. Treatment involved complex, prolonged antibiotic therapy (> 6 weeks in 84%) combined with neurosurgical drainage (91%) and source control surgery (34%). Mortality was 5% with 31% suffering long-term disability and 64% achieving a good clinical outcome. A reduced GCS, focal neurological deficit, and seizures at presentation were independently associated with an unfavorable clinical outcome (death or disability).

CONCLUSIONS

Complex surgical and antimicrobial treatment achieves a good outcome in the majority of patients with bacterial brain abscess and subdural empyema. Factors present at diagnosis can help to predict those likely to suffer adverse outcomes. Research to determine optimal surgical and antibiotic management would be valuable.

Anti-infective treatment of brain abscess

INTRODUCTION

Brain abscess is an uncommon and potentially life-threatening infection of the CNS that can be caused by a range of different pathogens including bacteria, fungi, and parasites. A multidisciplinary approach is important and anti-infective treatment remains crucial. Here, we review anti-infective treatment of brain abscess. Areas covered: We used the terms '(Brain abscess[ti] AND (antibiotic* OR treatment)) NOT case report'), to conduct a search in the PubMed. Additional papers were identified by cross-reference checking and by browsing textbooks of infectious diseases and neurology.

COMMENTARY

Empiric treatment of bacterial brain abscess consists of cefotaxime and metronidazole with the addition of vancomycin if meticilline-resistant Staphylococcus aureus is suspected. For severely immuno-suppressed patients, for example transplant recipients, voriconazole and trimethoprim-sulfamethoxazole or sulfadiazine should be added. Increased knowledge of the pharmacokinetic profile of anti-infective treatments may help to improve the treatment of brain abscess. Future studies should address efficacy and safety of continuous abscess drainage, mode of anti-infective administration (continuous vs. bolus), and anti-infective treatments in immuno-suppressed patients.

Focal intracranial infections due to Actinomyces species in immunocompetent patients: diagnostic and therapeutic challenges

OBJECTIVE

Actinomyces spp. are often underestimated as causes of central nervous system infection because they are not looked for routinely and are difficult to detect. We try to determine the optimal management of these problematic intracranial infectious diseases in neurosurgical practice.

METHODS

Five cases of intracranial suppurations due to Actinomyces spp. treated between December 2007 and February 2009 are reported. The relevant clinicobacteriologic features and treatment outcomes are analyzed.

RESULTS

There were two brain abscesses, two subdural empyemas, and one frontal sinus pyomucocele with intracranial extension. Among them, three cases were previously operated and two patients were previously treated for otorhinolaryngeal infection. All cases were immunocompetent. In addition to Actinomyces sp., three patients had coinfectious bacteria (Pseudomonas aeruginosa, Staphylococcus warneri, and Escherichia coli). Complete resolution of the infection was achieved by means of aggressive surgical treatment and relatively short course of antibiotic therapy with a full recovery.

CONCLUSION

Actinomycotic focal cerebral infections may occur with greater frequency than previously recognized. Polymicrobial bacteria may be seen. This rare anaerobic organism should be considered in patients with a history of head trauma, previous surgery, or otorhinolaryngeal infection who present with a long duration of neurologic symptoms with or without an accompanying fever. Patients may be candidates for surgical debridement with relative shorter term of antibiotic therapy (ciprofloxacin).

The role of beta-lactam/beta-lactamase inhibitor combinations in surgical infections

Many surgical infections are characterized by synergistic polymicrobial mixed infection, for which broad-spectrum antimicrobial therapy is usually administered on an empiric basis. Until relatively recently, standard empiric therapeutic regimens have involved the use of two or more antibiotics, such as aminoglycosides and anti-anaerobic agents, to achieve adequate aerobic and anaerobic coverage. There are often substantial drawbacks, however, such as drug-induced toxicity and high costs of treatment. Evidence from a number of clinical studies suggests that single-agent therapy with beta-lactam/beta-lactamase inhibitor combinations is a suitable and cost-effective alternative to multidrug regimens, as well as to monotherapy with cephalosporins or carbapenems in the treatment of intra-abdominal, gynecologic, and diabetic foot infections, and brain abscesses. These agents are also suitable for use in perioperative prophylaxis and may offer benefits over other agents in terms of reduced incidence of surgical wound infections and lower costs.

Diffusion-weighted MR imaging in the preoperative assessment of brain abscesses

BACKGROUND

Diffusion-weighted MR imaging (DWI) has recently shown promise in differentiating ring-enhancing lesions such as brain abscess and malignant neoplasm. The ability of DWI to strongly suggest brain abscess enables a neurosurgeon to alter stereotactic planning to optimize diagnosis. We report our experience with DWI in 5 patients with lesions on MR imaging and review the literature to assess the usefulness of this technique in the preoperative evaluation of cerebral abscess.

METHODS

The MR images of 5 patients presenting with ring-enhancing lesions that ultimately proved to be brain abscesses were retrospectively reviewed. In addition to standard MR sequences, trace DWI and apparent diffusion coefficient (ADC) calculations were performed on all patients. Additionally, 15 recently published articles or references in press concerning DWI in cerebral abscesses were reviewed.

RESULTS

All lesions were markedly hyperintense on DWI and had diminished ADC. Thirty-eight of 39 previously reported abscesses were hyperintense on DWI with reduced ADC. Of 165 nonpyogenic lesions with DWI findings, 87 were hypointense or isointense, 78 lesions had variable hyperintensities, and few manifested the degree of hyperintensity observed with abscesses. Most of these included chordomas and epidermoids, which are not likely to be confused with abscesses.

CONCLUSIONS

Restricted water diffusion, as indicated by hyperintensity on DWI and low ADC, in ring-enhancing lesions assists in differentiating brain abscess from necrotic tumor. This information facilitates stereotactic surgical planning: abscesses should be preferentially centrally aspirated, whereas necrotic brain tumors should have diagnostic tissue biopsied from cavity walls. Although not definitive for brain abscess, restricted water diffusion is an important MR imaging sign and is useful in neurosurgical treatment strategies for ring-enhancing lesions.

Oral microflora as a cause of endocarditis and other distant site infections

Bacteremia originating from the oral cavity is common, but the role of bacteremia in the genesis of infective endocarditis and other distant site infections is unclear. Only a small percentage of oral flora have been associated with distant site infection. Important issues remain unresolved concerning the identification of patients at risk, the relative risk from invasive dental procedures versus naturally occurring bacteremia, and the impact of prophylactic antibiotics on the incidence, nature, magnitude, and duration of bacteremia from the oral cavity. This article addresses the controversies in infection management in patients at risk for distant site infection.

The role of beta-lactam/beta-lactamase inhibitors in the management of mixed infections

Microbiological studies show that the in vitro antimicrobial activity of sulbactam-ampicillin encompasses not only gram-positive and gram-negative aerobes, but also anaerobes. Such a broad spectrum of activity suggests its suitability as monotherapy for the empiric management of polymicrobial infections. Typical mixed infections, which are frequently life-threatening, include those occurring in the abdomen or pelvis, diabetic foot infections, and brain abscess. Numerous comparative clinical studies have revealed the clinical and bacteriological efficacy of sulbactam-ampicillin to be comparable to that of imipenem cilastatin and the second-generation cephalosporins cefoxitin and cefotetan. In addition, other studies have demonstrated that sulbactam-ampicillin monotherapy is cost-beneficial. A reduction in the duration of hospitalization, the lack of potentially toxic side-effects, and lower drug costs associated with monotherapy all contribute to the cost-effectiveness of sulbactam-ampicillin.

Polymicrobial brain abscess involving Haemophilus paraphrophilus and Actinomyces odontolyticus

A case of brain abscess involving Haemophilus paraphrophilus and Actinomyces odontolyticus is presented. This combination of organisms has not previously been described. All brain abscess specimens should routinely be processed rapidly and cultured for a prolonged period to ensure recovery of fastidious organisms which may have implications for antibiotic therapy.

Ciprofloxacin and sparfloxacin penetration into human brain tissue and their activity as antagonists of GABAA receptor of rat vagus nerve

Patients undergoing elective surgery for removal of brain tumors, aneurysms, or other vascular malformations were administered a single oral dose of sparfloxacin (400 mg; 16 patients) or ciprofloxacin (750 mg; 5 patients) either 3 to 5 h or 22 to 26 h before surgery. Serum samples were taken from all patients at 0, 1, 3 to 5, 7 to 9, and 22 to 26 h after dosing; an additional serum sample was obtained at 48 h from patients who received sparfloxacin. A single sample of brain tissue was taken from all patients; a sample of cerebrospinal fluid (CSF) uncontaminated with blood was obtained from five patients. Serum and brain tissue samples were assayed by high-pressure liquid chromatography. Drug concentrations in brain tissue exceeded those in CSF by 1.8- to 19.4-fold. Kinetic modeling suggested that peak sparfloxacin concentrations in brain tissue may have occurred later than 3 to 5 h and that actual peak concentrations may therefore have been higher (up to 10 micrograms/g of tissue). The activities of ciprofloxacin and sparfloxacin as antagonists of the gamma-aminobutyric acid antagonist (GABAA) receptor were measured with the rat vagus nerve preparation. The 50% inhibitory concentration (IC50) of ciprofloxacin was 250 microM (95.25 micrograms/ml), but in the presence of biphenyl acetic acid (BPAA), the IC50 of ciprofloxacin was only 0.6 microM (0.23 microgram/ml). In contrast, the IC50 of sparfloxacin alone or in the presence of BPAA was > 300 microM (> 100 micrograms/ml). We conclude that the concentrations of ciprofloxacin and sparfloxacin in brain tissue may exceed serum drug concentrations and cannot be predicted from the concentrations in CSF. Sparfloxacin does not have any activity as a GABA antagonist, either alone or in the presence of BPAA, at the concentrations which are likely to be reached in human brain tissue.

Treatment of intracranial abscesses: experience with sulbactam/ampicillin

In an open prospective study, the efficacy of sulbactam/ampicillin (50 and 100 mg/kg, respectively, qid) was evaluated in 21 patients with intracranial abscess(es). Sixteen patients had cerebral, 3 epidural, and 2 cerebellar abscesses. Multiple lesions were found in 7 patients. Sixteen patients underwent surgical intervention, others were treated with antibiotic alone. The mean duration of antibiotic therapy (+/- SD) was 48 +/- 10 days (range 26-65 days). The mean duration of follow-up after completion of therapy (+/- SD) was 6 +/- 2.4 months. All patients had at least some reduction in size of abscess(es) within 3 weeks of the initiation of therapy as monitored by computerized tomography. Seventeen patients were cured, three patients died due to causes unrelated to their infection. One patient was reoperated since no clear improvement either clinically or radiologically was observed 18 days after the first operation. Side effects of sulbactam/ampicillin were minor and transient. Results obtained in this study indicate that sulbactam/ampicillin can be used in the treatment of intracranial abscesses, alone or with surgical intervention.

Enterococci in human periodontitis

Enterococci are potential pathogens in many human body sites. This study determined the subgingival occurrence and the in vitro antimicrobial susceptibility of enterococci in 100 persons with early-onset periodontitis and 545 persons with advanced adult periodontitis. Subgingival microbial samples were collected with paper points, transported in VMGA III and plated onto anaerobic enriched brucella blood agar or selective Enterococcosel agar (BBL Microbiology Systems). Enterococcal speciation was performed using commercial micromethod kit systems. In vitro sensitivity was determined using a commercial kit system and an agar dilution assay. Subgingival enterococci occurred in 1% of early-onset periodontitis patients and in approximately 5% of adult periodontitis patients. Enterococcus faecalis was the only enterococcal species recovered, and all but one isolate belonged to the same biotype. In vitro antimicrobial sensitivity testing revealed subgingival enterococci resistant to therapeutic levels of penicillin G, tetracycline, clindamycin and metronidazole, but relatively sensitive to ciprofloxacin and amoxicillin/potassium clavulanate (Augmentin). Enterococci may populate periodontal pockets as superinfecting organisms and, in heavily infected patients, may contribute to periodontal breakdown.