Bacteriologic Diagnosis in Therapy of Infectious Complications in Neurosurgical Cases

I.A. Aleksandrova, S.Yu. Sazykina, V.F. Imshenetskaya

(Burdenko Research Institute of Neurosurgery, Moscow)

Treatment of infectious intracranial complications has specific peculiarities due to existence of barrier structures, hampering penetration of drugs into the brain and CSF. Thus, a choice of an antibacterial drug for treatment of postoperative meningitis (PM) is a serious problem. As a rule, initial therapy of PM with antibiotics is of an empirical character, as bacteriologic diagnosis demands time and use of antibacterial drugs cannot be postponed. When this diagnosis is made, individual etiotropic therapy is prescribed by a clinician in active participation of laboratory employees, interpreting antibiograms of a specific agent and recommending drugs with taking into account its pharmacokinetics and pharmacoeconomics. If necessary, empiric prescription of drugs can be corrected in compliance with data on resistance to used preparations.

Results of continuous bacteriologic monitoring (1993-2003) have demonstrated, that despite annual fluctuations a structure and properties of a microbial factor of PM are almost homogenous. Predominant agents are Gram-positive microorganisms (50% on the average), represented mainly by coagulase-negative staphylococci (more than 83%). There is a high level of methycillin-resistant strains (60%). PM is caused by a monoculture agent in 97% of cases.

One third of all the agents is Gram-negative pathogens. ESBL-producing strains (Klebsiella pneumoniae, Escherichia coli, Enterovacter spp.) are predominant in the family of Enterobacteriaceae, but their number becomes considerably smaller with an increase of an amount of non-fermenting microorganisms. As for non-fermenting Gram-negative agents, causing the most severe PM, one can watch a growing role of Pseudomonas aeruginosa and multiresistant strains of Acinetobacter spp.

As an etiologic agent of PM is usually represented by one species of microorganisms, it is expedient to carry out etiotropic therapy with one drug (monotherapy), possessing a specific spectrum of action. Maximum doses of antibiotics, ensuring bactericidal concentration in CSF, are used during the whole course of treatment. If necessary, a drug is administered intrathecally. A course duration is no less than 2 weeks.

Biological monitoring of a structure of agents, causing PM, and their resistance to antibiotics allows to choose an optimum antibiotic in its empiric prescription. A substantiated approach to a drug choice determines efficacy of rational antibacterial treatment of infectious complications in neurosurgical cases. Success of treatment depends on timely exact bacteriologic diagnosis and an adequate choice of an antibacterial drug. Thus, a bacteriologic laboratory and epidemiologic service of a medical establishment play a leading part in prevention and treatment of infectious complications.