Utility of in vitro proton magnetic resonance spectroscopy in aetiological characterisation of brain abscesses.

Purpose: Brain abscesses often present an aetiological dilemma. Microscopy is insensitive and culture techniques are time consuming. Hence, a new rapid technique in vitro Proton Magnetic Resonance Spectroscopy ( 1 HMRS) was evaluated for its usefulness in the identification of aetiology of brain abscesses. Materials and Methods: A total of 39 pus specimens from brain abscesses were subjected to in vitro 1 HMRS. These pus specimens were also processed by conventional culture methods. The spectral patterns generated by in vitro 1 HMRS were further correlated with culture results. Results: Pus specimens which showed the presence of anaerobes on culture revealed the presence of multiplet at 0.9 ppm (100%), lactate-lipid at 1.3 ppm (100%), acetate at 1.92 ppm (100%) and succinate at 2.4 ppm (75%). Pus specimens that revealed the presence of facultative anaerobes on culture showed a pattern B, i.e., the presence of lactate-lipid at 1.3 ppm (100%), acetate at 1.92 ppm (88.88%) along with the multiplet at 0.9 ppm (100%). Pattern C was seen in aerobic infection which showed the presence of lactate-lipid at 1.3 ppm (100%) along with the multiplet at 0.9 ppm. Pus from two tuberculous abscesses showed the complete absence of multiplet at 0.9 ppm. Conclusions: We observed in this study that it was possible to differentiate bacterial and tuberculous brain abscesses using in vitro 1 HMRS. Further, it was also possible to distinguish between aerobic and anaerobic brain abscesses on the basis of spectral patterns. In vitro 1 HMRS of fungal and actinomycotic brain abscess are also presented for its unusual spectra.

Rapid identification of non-sporing anaerobes using nuclear magnetic resonance spectroscopy and an identification strategy.

PURPOSE: The non-sporing anaerobes cause a wide spectrum of infections. They are difficult to culture and their identification is tedious and time-consuming. Rapid identification of anaerobes is highly desirable. Towards this end, the potential of nuclear magnetic resonance (NMR) spectroscopy for providing a fingerprint within the proton spectrum of six genera belonging to anaerobes reflecting their characteristic metabolites has been investigated. METHODS: NMR analysis was carried out using Mercury plus Varian 300 MHz (7.05 T) NMR spectrophotometer on six different anaerobes. These included Bacteroides fragilis, Prevotella melaninogenica, Prevotella denticola, Fusobacterium necrophorum, Peptococcus niger and Peptostreptococcus spp. After the NMR analysis (256/512 scans), the different peaks were noted. The eight pus specimens, which yielded pure culture of anaerobe, also were analysed similarly. RESULTS: The major resonances of multiplex of amino acids/lipid at 0.9 ppm along with lactate/lipid at 1.3 ppm, acetate at 1.92 ppm and multiplex of lysine at 3.0 ppm remained constant to label the organism as an anaerobe. There was a difference found in the MR spectra of different genera and species. A simple algorithm was developed for the identification of the six different anaerobes studied. The MR spectra of the pure culture of the organism matched the MR spectra of pus from which the organism was isolated. CONCLUSIONS: MR-based identification was of value in the identification of anaerobes. However, a larger database of the peaks produced by anaerobes needs to be created for identification of all genera and species. It could then have the potential of diagnosing an anaerobic infection in vivo and thus expedite management of deep-seated abscesses.

Cefoperazone monotherapy for serious infections in hospitalized patients--an initial Indian experience.

Cefoperazone sodium is a broad spectrum third generation Cephalosporin recently introduced in India. This was used as a monotherapy to treat severe infections in hospitalized patients. These infections were due to various gram positive and gram negative organisms. Of the 22 evaluable patients, 21 (95%) were clinically cured and 1 (5%) improved. 18 pathogens were isolated from 17 patients. Microbiologic eradication was 100%. Symptomatic improvement occurred within 48-72 hours of onset of therapy with complete relief by 4-5 days. Dual mode of excretion makes this drug safe in presence of renal insufficiency. Anti-microbial activity against a wide spectrum of organisms and twice daily dosage schedule qualify Cefoperazone as a single antibiotic of choice in severe infections in critically ill patients.

Multi drug resistant Salmonella typhi in Bombay.

An outbreak called 'Dombivali fever' started in March 1990 and spread rapidly all over Bombay and adjoining area. A concomitant and steady increase in multidrug resistant Salmonella typhi isolation was observed. Later this outbreak called 'Dombivali fever' was proved to be resistant typhoid fever only. The present paper deals with comparison of this outbreak with previous two years laboratory data from Sir J.J. Hospital, Bombay. A very high isolation rate of S. typhi (215 isolates) in 1990 as compared to 62 isolates in the last two years (1988-89), was observed in this laboratory. The incidence of multidrug resistance in cases of enteric fever (EF) was also very high (67.6%) in 1990, as compared to 6.2% in 1988 and 23.3% in 1989. All the strains tested in 1990 were sensitive to ciprofloxacin.