Related Experiment Videos
The antibacterial effect of some neuroleptics on strains isolated from patients with meningitis
I Mortensen1, J E Kristiansen, A V Christensen
1Department of Antibiotics, Statens Seruminstitut, Copenhagen, Denmark.
Abstract:
Eighty-two strains of bacteria (Neisseria meningitidis, Haemophilus influenzae, Enterobacteriaceae, Streptococcus pneumoniae, group B streptococci and Listeria monocytogenes) were examined for their in vitro susceptibility to eight drugs, seven neuroleptics (perphenazine, fluphenazine, cis(Z)-clopenthixol, haloperidol, clozapine, clebopride and SCH 23390), and the neuroleptically inactive trans(E)-clopenthixol. The phenothiazines and the thioxanthenes were, on the whole, the most active drugs when measured, the IC50(50) for each group of bacteria being 7.4 to 84 mg/l (with the exception of the activity against the enterobacteriaceae). The antibacterial potency of clozapine, which has an atypical neuroleptic profile, was between 50 and 140 mg/l. Haloperidol also showed an antibacterial activity in the concentration range 35-140 mg/l. The selective D1 antagonist, SCH 23390 and the selective D2 antagonist, clebopride, inhibited only few of the bacteria in the concentration range investigated.
Insights
Certain neuroleptic drugs, including phenothiazines and thioxanthenes, demonstrate significant in vitro antibacterial activity against common pathogens like Streptococcus pneumoniae. Clozapine and haloperidol also show antibacterial effects, while selective antagonists have limited impact.
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Bacterial meningitis and other infections are significant public health concerns.
- Neuroleptic drugs are primarily used for psychiatric conditions.
- Investigating non-psychiatric applications of existing drugs can accelerate therapeutic development.
Purpose of the Study:
- To evaluate the in vitro antibacterial activity of various neuroleptic drugs.
- To determine the susceptibility of common bacterial pathogens to a panel of neuroleptics.
- To compare the efficacy of different classes of neuroleptics against bacteria.
Main Methods:
- Testing 82 bacterial strains including Neisseria meningitidis, Haemophilus influenzae, Enterobacteriaceae, Streptococcus pneumoniae, group B streptococci, and Listeria monocytogenes.
- Assessing in vitro susceptibility to eight neuroleptic drugs: perphenazine, fluphenazine, cis(Z)-clopenthixol, haloperidol, clozapine, clebopride, and SCH 23390, plus trans(E)-clopenthixol.
- Measuring inhibitory concentrations (IC50) to quantify antibacterial potency.
Main Results:
- Phenothiazines and thioxanthenes exhibited the most potent antibacterial activity, with IC50 values ranging from 7.4 to 84 mg/l against most tested bacteria.
- Clozapine demonstrated antibacterial potency between 50 and 140 mg/l, while haloperidol showed activity in the 35-140 mg/l range.
- Selective D1 antagonist SCH 23390 and selective D2 antagonist clebopride displayed limited antibacterial effects within the investigated concentration range.
Conclusions:
- Several neuroleptic drugs possess significant in vitro antibacterial properties.
- Phenothiazines and thioxanthenes are particularly effective against a range of bacterial pathogens.
- Further research into repurposing neuroleptics for antibacterial applications may be warranted.