Meningococcal disease--some issues in treatment

Practice patterns of infectious disease physicians for management of meningococcal disease

BACKGROUND

Although empiric treatment regimens for acute bacterial meningitis are well established, there are many uncertainties regarding management of meningococcal disease. A survey was conducted among infectious disease specialists to assess meningococcal disease practice patterns and availability of antimicrobial susceptibility testing for Neisseria menigitidis.

METHODS

An online survey was distributed to 1342 pediatric and adult infectious disease specialists to assess common practices and opinions regarding the diagnosis, treatment and prevention of meningococcal disease. Specialists were also asked about the availability of antimicrobial susceptibility testing for Neisseria meningitidis at their clinical microbiology laboratory.

RESULTS

Six hundred fifty members responded to the survey (48%). Pediatric infectious disease specialists were more likely than adult specialists to use penicillin as definitive therapy for meningococcal disease (56% versus 46%; P = 0.038). Most pediatric specialists who would narrow therapy report that they would only switch to penicillin upon confirmation of penicillin susceptibility (55%), although 44% would narrow therapy based on a N. meningitidis species confirmation alone. More than one third of respondents reported that susceptibility testing for N. meningitidis is not routinely performed. There was also wide variation in complement deficiency screening criteria and meningococcal disease chemoprophylaxis practices among respondents.

CONCLUSIONS

Infectious disease specialists vary significantly in their practices regarding several aspects of meningococcal disease diagnosis, treatment and prevention. Antimicrobial susceptibility testing for N. meningitidis is not routinely performed in many practices. Consideration of these variations would be useful when developing treatment and prevention recommendations.

Emerging resistance in Neisseria meningitidis and Neisseria gonorrhoeae

The value of monitoring antimicrobial resistance is particularly significant for Neisseria meningitidis and Neisseria gonorrhoeae diseases, even if it is for different reasons. Although there is no global alert for the spread of resistant meningococcal strains, the emergence of resistance is correlated to the outcome of treatment and the successful prophylaxis of close contacts. Few cases of resistance among meningococci have been recorded worldwide; it remains unclear what intriguing mechanism is responsible for maintaining resistance in these cases in the absence of significant antibiotic selective pressure, as in the case of penicillin; on the contrary, although rifampicin is the antibiotic of choice in the prophylaxis of close contacts, there is a very low rate of resistance. The emergence of multidrug-resistant N. gonorrhoeae is a great challenge in controlling gonorrhea as one of the main sexually transmitted bacterial diseases. International surveillance programs permit the monitoring of the susceptibility of the pathogen and allow the revision of the standardized treatment regimen when the situation changes.

Current concepts in the role of the host response in Neisseria meningitidis septic shock

Lipopolysaccharides in the outer membrane of Neisseria meningitidis are key molecules that induce inflammation and cause meningitis and shock. Mutant strains, with altered lipid A, the toxic moiety of lipopolysaccharide, or completely lacking lipopolysaccharide, induce significantly less inflammation than wild-type strains. Polymorphism of the Fc gamma receptors and interleukin-10 gene but not of the Toll-like receptor 4 may influence the development of meningococcal infection. Mannan-binding lectin is involved in complement activation, the regulation of adhesion molecules and cytokine production induced by meningococci. The activation of protein C by the thrombomodulin protein C receptor complex on the endothelial cell surface appears to be reduced in meningococcal sepsis but is still sufficient to convert protein C to activated protein C in patients treated with concentrated protein C.