Following an initial response to vancomycin therapy, a patient with meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia developed endocarditis, failed a second course of vancomycin and then failed daptomycin therapy. An increase in the vancomycin minimum inhibitory concentrations of four consecutive MRSA blood isolates from 2 μg/mL to 8 μg/mL was shown by Etest. Population analysis of four successive blood culture isolates recovered over the 10-week period showed that the MRSA strain became progressively less susceptible to both vancomycin and daptomycin. Retrospectively, the macro Etest method using teicoplanin indicated a decrease in vancomycin susceptibility in the second blood isolate. The patient improved after treatment with various courses of trimethoprim/sulphamethoxazole, quinupristin/dalfopristin and linezolid. Early detection of vancomycin-heteroresistant S. aureus isolates, which appeared to have clinical significance in this case, continues to be a challenge for the clinical laboratory. Development of suitable practical methods for this should be given priority. Concurrent development of resistance to vancomycin and daptomycin, whilst rare, must be considered in a patient who is unresponsive to daptomycin following vancomycin therapy.

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Meningitis caused by Mycobacterium tuberculosis remains an important cause of morbidity and mortality worldwide, and presents specific challenges in terms of diagnosis and management. The nonspecific clinical presentation of tuberculous meningitis has led researchers to develop newer biochemical and molecular methods of making the diagnosis. Several of these methods have excellent sensitivity and specificity, although are not yet available for clinical use. Successful therapy for tuberculous meningitis requires a combination of antimicrobial agents, with vigilance towards the possibility of disease caused by resistant organisms. Adjunctive corticosteroids also have a role in treating this potentially devastating infection. With proper therapy, morbidity and mortality can be minimized in patients with tuberculous meningitis.

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