In vitro activities of cefotaxime, vancomycin, quinupristin/dalfopristin, linezolid and other antibiotics alone and in combination against Propionibacterium acnes isolates from central nervous system infections

Is Cutibacterium acnes early surgical site infection rate related to the duration of antibiotic prophylaxis in adolescent idiopathic scoliosis surgery?

PURPOSE

Cutibacterium acnes (C. acnes) is a gram-positive anaerobic bacillus located in pilosebaceous glands, usually responsible for late postoperative surgical site infections (SSI). A recent study performed in our institution highlighted an unexpected emergence of C. acnes early SSI. One potential explanation was the change of the perioperative antibioprophylaxis (ATB) protocol, which switched from 48 h postoperative cefamandole to intraoperative only cefazoline. The aim of this study was therefore to investigate the influence of the ATB duration on the occurrence of C. acnes early SSI, by comparing the incidence rates during 3 consecutive ATB protocols.

METHODS

Between January 2007 and September 2017, all patients who underwent posterior fusion for AIS were retrospectively reviewed. Early C. acnes SSI were reported and compared between 3 periods, during which the ATB protocols were modified. January 2007-February 2012: Intraoperative Cefamandole continued 48 h (protocol 1) March 2012-August 2016: Single shot of intraoperative Cefazoline (protocol 2) September 2016-September 2017: Intraoperative Cefazoline continued 48 h (protocol 3).

RESULTS

Fifty-three early SSI (7.2%) were reported among the 732 posterior AIS fusions included. Global incidence of C. acnes infection was 2.9%. The incidence of C. acnes in early SSI increased from 0 to 4.9% between protocol 1 and 2, but was reduced to 1.7% with protocol 3.

CONCLUSIONS

Early C acnes SSI can be explained by the difficulty to eradicate this pathogen with current skin preparation procedures and some Beta-lactam antibiotics tolerance. Longer duration antibioprophylaxis is preferable to prevent from early C. acnes SSI.

Cerebral empyema and abscesses due to Cutibacterium acnes

INTRODUCTION

Cutibacterium acnes is a commensal bacterium of the skin, frequently reported in prosthetic shoulder or spinal implant infections, but rarely in cranial and intracranial infections.

METHODS

We retrospectively reviewed patients with intracranial samples positive to Cutibacterium acnes managed in the neurosurgical units of our hospital of Lyon, France, between 2008-2016.

RESULTS

We included 29 patients, of whom 23 had empyema (with or without abscess), 17 had cranial osteomyelitis, and six only had abscess. Prior neurosurgery was reported in 28 patients, and the remaining patient had four spontaneous abscesses. Twelve patients had polymicrobial infections, including methicillin-susceptible Staphylococcus in 11 cases. The clinical diagnosis was difficult because of indolent and delayed symptoms: a CT scan or MRI was required. Thirteen patients (52%) had material at the infection site. All patients with bone flap implant or bones from biological banks had a bone flap-associated infection. Drainage was surgically performed in 25 cases or by CT scan-guided aspiration in four cases. All patients received an adapted antibiotic therapy (from three weeks to six months). The outcome was favorable in 28 patients. Three patients relapsed during the antibiotic therapy, requiring further surgery.

CONCLUSION

Cutibacterium acnes can be responsible for postoperative empyema and cerebral abscesses, with particular indolent forms, which make their diagnosis difficult. They are often polymicrobial and associated with bone flap osteomyelitis. Their outcome is favorable after drainage and adapted antibiotic therapy.

Clinical Features of Infectious Keratitis Caused by Propionibacterium Acnes

PURPOSE

Propionibacterium acnes is a commensal bacteria whose pathogenicity in infectious keratitis is unclear. In this study, we report infectious keratitis cultured with P. acnes and evaluate its clinical characteristics.

METHODS

All cases of infectious keratitis submitted to the microbiology laboratory of St. Mary's Hospital of Seoul between January 2013 and April 2014 were reviewed. Nonpretreated cases that were positive for P. acnes were identified, and clinical characteristics and treatment outcomes were studied.

RESULTS

Of 132 cultures submitted to the microbiology laboratory, 89 (67.4%) were positive for growth, and a total of 16 (17.9%) of the 89 cases yielded P. acnes in culture medium. Infectious keratitis that was positive for P. acnes was generally small (62.5%) with deep stromal infiltration (81.25%) and a peripheral location (56.25%). The average incubation period was 11.06±5.76 days, and the average time to reepithelialization was 23.50+13.52 days. All the cases of P. acnes evaluated in this report responded well to medical treatment.

CONCLUSIONS

Infectious keratitis with P. acnes is not uncommon and can be confused with other Gram-positive cocci. Thus, P. acnes should be suspected in small-sized keratitis with an unusually long incubation period.

Persistent extra-axial post-surgical collections and Propionibacterium acnes infection. Presentation of two cases and literature review

OBJECTIVES

It is common to observe the persistence of extra-axial collections after craniotomies. Most of these disappear in weeks or months but some remain. The onset of focal symptoms or the growth of these persistent collections months or years after surgery may indicate the presence of a chronic and latent infection by germs of low virulence such as Propionibacterium acnes (P. acnes).

METHODS

We present two clinical cases with persistent extra-axial collections, which required surgery years after diagnosis, in which P. acnes was isolated as an aetiological agent and we reviewed the literature published in this regard.

RESULTS

These are two patients who, following surgical procedures (decompressive craniectomy for severe TBI and craniotomy for right parietal meningioma) and extra-axial collections were kept, which were monitored over time and then were infected and required emergency evacuation. In these collections P. acnes grew as a causal agent and required targeted antibiotics.

CONCLUSIONS

We must consider P. acnes as an infectious agent of post-surgical collections of long evolution. Atypical presentation and radiological changes may be helpful in diagnosis.

Acute Hemiparesis in a Healthy Elderly Woman: Where and What Is the Lesion?

Hemiparesis may be the result of lesions in the contralateral pyramidal tract in the brain or, less frequently, in the ipsilateral pyramidal tract in the upper cervical spinal cord. However, although rare, multiple lesions that simultaneously occur in both of these regions may be the cause of acute hemiparesis, and the clinical symptoms can often be misdiagnosed as a stroke. In addition, the correct diagnosis of these multiple central nervous system (CNS) lesions is very challenging if they are caused by infection from an unexpected microorganism. We evaluated an elderly healthy woman who presented with acute hemiparesis and multiple brain and spinal cord lesions that were confirmed to occur from an infection with Propionibacterium acnes. In this report, the differential diagnosis and histopathological findings are discussed for these multiple CNS lesions in this healthy woman.

Quantification of the antibody response to Propionibacterium acnes in a patient with prosthetic valve endocarditis: - a case report

Background

The isolation of Propionibacterium acnes in blood cultures is often considered a contaminant. On rare occasions, P. acnes can cause severe infections, including endocarditis and intravascular prosthesis-associated infections. To evaluate the discrimination between a contaminant and a clinically relevant infection we used an Ouchterlony test system to quantify the antibody response to P. acnes in a patient with a proven P. acnes endocarditis.

Case presentation

We report on a 64-year-old Caucasian man who developed P. acnes endocarditis four years following a composite valve-graft conduit replacement of the aortic root. Bacterial growth in blood cultures was detected after an incubation period of 6 days. However, the antibody titer to P. acnes was 1:8 at the time of diagnosis and declined slowly thereafter over 2½ years. The patient’s response to the antibiotic treatment was excellent, and no surgical re-intervention was necessary.

Conclusion

The working hypothesis of infective endocarditis can be substantiated by serologic testing, which, if positive, provides one additional minor criterion. Moreover, quantification of the antibody response to P. acnes, though not specific, may assist in the differentiation between contaminants and an infection. This quantification may have implications for the patient management, e.g. indication for and choice of the antibiotic therapy.

Genotypic and antimicrobial characterisation of Propionibacterium acnes isolates from surgically excised lumbar disc herniations

The anaerobic skin commensal Propionibacterium acnes is an underestimated cause of human infections and clinical conditions. Previous studies have suggested a role for the bacterium in lumbar disc herniation and infection. To further investigate this, five biopsy samples were surgically excised from each of 64 patients with lumbar disc herniation. P. acnes and other bacteria were detected by anaerobic culture, followed by biochemical and PCR-based identification. In total, 24/64 (38%) patients had evidence of P. acnes in their excised herniated disc tissue. Using recA and mAb typing methods, 52% of the isolates were type II (50% of culture-positive patients), while type IA strains accounted for 28% of isolates (42% patients). Type III (11% isolates; 21% patients) and type IB strains (9% isolates; 17% patients) were detected less frequently. The MIC values for all isolates were lowest for amoxicillin, ciprofloxacin, erythromycin, rifampicin, tetracycline, and vancomycin (≤1mg/L). The MIC for fusidic acid was 1-2 mg/L. The MIC for trimethoprim and gentamicin was 2 to ≥4 mg/L. The demonstration that type II and III strains, which are not frequently recovered from skin, predominated within our isolate collection (63%) suggests that the role of P. acnes in lumbar disc herniation should not be readily dismissed.

Mechanism-independent method for predicting response to multidrug combinations in bacteria

Drugs are commonly used in combinations larger than two for treating bacterial infection. However, it is generally impossible to infer directly from the effects of individual drugs the net effect of a multidrug combination. Here we develop a mechanism-independent method for predicting the microbial growth response to combinations of more than two drugs. Performing experiments in both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, we demonstrate that for a wide range of drugs, the bacterial responses to drug pairs are sufficient to infer the effects of larger drug combinations. To experimentally establish the broad applicability of the method, we use drug combinations comprising protein synthesis inhibitors (macrolides, aminoglycosides, tetracyclines, lincosamides, and chloramphenicol), DNA synthesis inhibitors (fluoroquinolones and quinolones), folic acid synthesis inhibitors (sulfonamides and diaminopyrimidines), cell wall synthesis inhibitors, polypeptide antibiotics, preservatives, and analgesics. Moreover, we show that the microbial responses to these drug combinations can be predicted using a simple formula that should be widely applicable in pharmacology. These findings offer a powerful, readily accessible method for the rational design of candidate therapies using combinations of more than two drugs. In addition, the accurate predictions of this framework raise the question of whether the multidrug response in bacteria obeys statistical, rather than chemical, laws for combinations larger than two.

Propionibacterium acnes endocarditis in an adolescent boy suffering from a congenital cardiopathy

Propionibacterium acnes endocarditis is an uncommon infection in pediatrics. We describe a case of P. acnes endocarditis in a 16-year-old boy that occurred 6 months after recurrent surgery for a congenital cardiopathy. Molecular identification of P. acnes was obtained. He recovered from this infection after a surgical treatment and with a prolonged antibiotic regimen including ceftriaxone.