A case of brain abscess caused by Propionibacterium acnes 13 months after neurosurgery and confirmed by 16S rRNA gene sequencing

Propionibacterium acnes is a gram-positive anaerobic bacillus and a normal inhabitant of the skin. Although it is often considered a contaminant of blood cultures, it can occasionally cause serious infections, including postoperative central nervous system infections. Here, we report the case of a 70-yr-old man who developed a large cerebral abscess caused by P. acnes 13 months after neurosurgery. Immediate gram staining of the pus from his brain revealed the presence of gram-positive coccobacilli. However, colony growth was observed only after 5 days of culture. Therefore, we performed 16S rRNA gene sequencing of the pus specimen. The isolate was identified as P. acnes. The colonies developed 9 days after the initial culture. The API Rapid ID 32A test (bioMérieux, France) was performed using a colony, but an unacceptable profile was obtained. Then, the pus was transferred into the enrichment broths of the BACTEC FX (Becton Dickinson, USA) and BacT/Alert 3D (bioMérieux, Organon Teknika, USA) systems, but only the BACTEC FX system could detect growth after 5 days. We performed 16S rRNA gene sequencing and API Rapid 32A profiling with a colony recovered from Brucella agar, which was inoculated with the microbial growth in the enrichment broth from the BACTEC FX system. The organism was identified as P. acnes by both methods. This case suggests that 16S rRNA gene sequencing may be a useful alternative for identifying slowly growing P. acnes from specimens that do not show growth after 5 days of culture.

Relationship between bacterial colonization of external cerebrospinal fluid drains and secondary meningitis: a retrospective analysis of an 8-year period

Object

A frequent complication of CSF drains is secondary meningitis. This study was designed to assess the predictive value of a positive culture from a CSF drain tip for the development of secondary meningitis.

Methods

The authors conducted a retrospective study of an 8-year period in which patients were treated in a tertiary care hospital in The Netherlands. Patients with positive cultures from CSF drain tips were identified from the microbiology database. Patient charts were reviewed to retrieve demographic, clinical, and laboratory data. Statistical analysis was performed using multivariate logistic regression to determine significant risk factors for the development of secondary meningitis.

Results

A total of 139 patients with positive CSF-drain cultures were included; 72 patients (52%) suffered secondary meningitis at the time of CSF drain removal, or developed it consecutively. Development of secondary meningitis was associated with use of ventricular drains (OR 3.4 vs lumbar drains; 95% CI 1.7–6.8), with age less than 18 years (OR 4.7; 95% CI 1.3–17.3), and with colonization with Staphylococcus aureus (OR 3.1 vs other microorganisms; CI 1.2–8.5). Thirty-two patients (44% of total secondary meningitis) were diagnosed with secondary meningitis 24 hours or more after CSF drain removal; in 13 patients (18%) the diagnosis was made after 48 hours or more.

Conclusions

Positive CSF-drain cultures are strongly associated with development of secondary meningitis. A positive CSF-drain culture may precede clinical symptoms and should therefore be communicated to the treating physician by the microbiological laboratory as soon as possible, and prophylactic antibiotic therapy should be considered.

Massive ascites as unique sign of shunt infection by Propionibacterium acnes

Propionibacterium acnes (P. acnes) has been associated with shunt infection. The signs of infection are mild. We report on a case of P. acnes shunt infection presenting with massive ascites as the unique sign of CSF infection. Shunt removal, antibiotic therapy and drenaige of ascites were performed with a rapid clinical recovery.

Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis

The epidemiology of bacterial meningitis has changed as a result of the widespread use of conjugate vaccines and preventive antimicrobial treatment of pregnant women. Given the significant morbidity and mortality associated with bacterial meningitis, accurate information is necessary regarding the important etiological agents and populations at risk to ascertain public health measures and ensure appropriate management. In this review, we describe the changing epidemiology of bacterial meningitis in the United States and throughout the world by reviewing the global changes in etiological agents followed by specific microorganism data on the impact of the development and widespread use of conjugate vaccines. We provide recommendations for empirical antimicrobial and adjunctive treatments for clinical subgroups and review available laboratory methods in making the etiological diagnosis of bacterial meningitis. Finally, we summarize risk factors, clinical features, and microbiological diagnostics for the specific bacteria causing this disease.

A simple method to reduce infection of ventriculoperitoneal shunts

OBJECT

Postoperative shunt infection is the most common and feared complication of ventriculoperitoneal (VP) shunt placement for treatment of hydrocephalus. The rate of shunt infection is highest in the 1st postoperative month. The most common organisms responsible for shunt infection include coagulase-negative Staphylococcus and Staphylococcus aureus. This suggests a transfer of patient's skin flora via the surgeons' glove as a possible means of infection. The authors conducted a study to determine if the rate of postoperative shunt infections could be reduced simply by changing gloves before handling the shunt catheter.

METHODS

A total of 111 neonates born with congenital hydrocephalus requiring a VP shunt were enrolled retrospectively and divided into 2 groups: a control group of 54 neonates treated with standard protocol VP shunt placement (Group A) and a treatment group of 57 neonates in whom, after initially double gloving, the outer pair of gloves was removed before handling the shunt catheter (Group B). Shunt infection rates were compared up to 6 months postoperatively.

RESULTS

There was a statistically significant reduction of infection rate from 16.33% in Group A (control) to 3.77% in Group B (p = 0.0458).

CONCLUSIONS

The study shows that a changing of gloves before handling the shunt catheter may be a simple and cost-effective way to reduce the burden of postoperative shunt infections.

Rifampin combination therapy for nonmycobacterial infections

The increasing emergence of antimicrobial-resistant organisms, especially methicillin-resistant Staphylococcus aureus (MRSA), has resulted in the increased use of rifampin combination therapy. The data supporting rifampin combination therapy in nonmycobacterial infections are limited by a lack of significantly controlled clinical studies. Therefore, its current use is based upon in vitro or in vivo data or retrospective case series, all with major limitations. A prominent observation from this review is that rifampin combination therapy appears to have improved treatment outcomes in cases in which there is a low organism burden, such as biofilm infections, but is less effective when effective surgery to obtain source control is not performed. The clinical data support rifampin combination therapy for the treatment of prosthetic joint infections due to methicillin-sensitive S. aureus (MSSA) after extensive debridement and for the treatment of prosthetic heart valve infections due to coagulase-negative staphylococci. Importantly, rifampin-vancomycin combination therapy has not shown any benefit over vancomycin monotherapy against MRSA infections either clinically or experimentally. Rifampin combination therapy with daptomycin, fusidic acid, and linezolid needs further exploration for these severe MRSA infections. Lastly, an assessment of the risk-benefits is needed before the addition of rifampin to other antimicrobials is considered to avoid drug interactions or other drug toxicities.

Infectious risk to ventriculo-peritoneal shunts from gastrointestinal surgery in the pediatric population

PURPOSE

The infectious implication of abdominal surgeries on ventriculo-peritoneal (VP) shunts, including simultaneous shunt placement and management of shunt infections, has been ill defined in children.

METHODS

We conducted a 9-year retrospective review of pediatric patients with VP shunts who underwent abdominal surgeries.

RESULTS

Forty-two patients fit criteria. The median age at shunt placement was 1.75 years, and the median time between shunt placement and abdominal surgery was 24 days. The most common procedures included gastrostomy (17), fundoplication (15), and appendectomy (3). Seven patients had simultaneous abdominal surgery and shunt placement. All patients received preoperative antibiotics. Two children developed shunt infections, both occurred after appendectomy. Both were treated with antibiotics, with one requiring shunt removal. Median length of stay was 24 days but 28 days for those with infections. Thirty-eight patients were discharged home, 3 to chronic care facilities, and 1 died.

CONCLUSIONS

Infections did not occur in children with VP shunts undergoing elective abdominal procedures or procedures simultaneously with shunt insertion. Infections were seen only with emergent appendectomies, suggesting that performing gastrointestinal procedures at the time of VP shunt insertion is safe. Children with VP shunts undergoing emergent surgery for peritoneal infection warrant close observation for shunt infection.