Background-There are few data on paediatric community acquired pneumonia (PCAP) in the UK. Aims-To investigate the aetiology and most useful diagnostic tests for PCAP in the north east of England. Methods-A prospective study of hospital admissions with a diagnosis of PCAP. Results-A pathogen was isolated from 60% (81/136) of cases, and considered a definite or probable cause of their pneumonia in 51% (70/136). Fifty (37%) had a virus implicated (65% respiratory syncytial virus) and 19 (14%) a bacterium (7% group A streptococcus, 4% Streptococcus pneumoniae), with one mixed infection. Of a subgroup (51 patients) in whom serum antipneumolysin antibody testing was performed, 6% had evidence of pneumococcal infection, and all were under 2 years old. The best diagnostic yield was from paired serology (34%, 31/87), followed by viral immunofluorescence (33%, 32/98). Conclusion-Viral infection accounted for 71% of the cases diagnosed. Group A streptococcus was the most common bacterial infective agent, with a low incidence of both Mycoplasma pneumoniae and S pneumoniae. Pneumococcal pneumonia was the most common bacterial cause of pneumonia in children under 2 years but not in older children. Inflammatory markers and chest x ray features did not diVerentiate viral from bacterial pneumonia; serology and viral immunofluorescence were the most useful diagnostic tests. (Arch Dis Child 2000;83:408-412)

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Twenty percentage of cases of empyema in our series were complicated by cavitatory lung disease. It is an important complication of childhood empyema associated classically with S. aureus, but these data suggest that S. pneumoniae now appears to be the main cause. There does not seem to be an association with any particular serotype.

A strain isolated from a biopsy sample taken from a slowly spreading skin granulation on a child's hand was found to have properties consistent with its classification in the genus Mycobacterium. An almost complete gene sequence of the 16s rRNA of the strain was determined following the cloning and sequencing of the amplified gene. The sequence was aligned with those available for mycobacteria, and phylogenetic trees were inferred with four tree-making algorithms. The organism, which formed a distinct phyletic line within the evolutionary radiation occupied by rapidly growing mycobacteria, was readily distinguished from members of validly described species of rapidly growing mycobacteria on the basis of its mycolic acid pattern and a number of other phenotypic features, notably its ability to form yellow pigmented colonies when incubated in the light. The name proposed for this new species is Mycobacterium novocastrense. The type strain is DSM 44203.A relatively rapidly growing, weakly acid-alcohol-fast organism was isolated from biopsy tissue of a patient who had received six weeks of antituberculosis therapy. The strain had phenotypic properties consistent with its classification in the genus Mycobacterium, and these set it apart from other rapidly growing mycobacteria. In the present investigation, the organism was the subject of a polyphasic taxonomic study designed to clarify its taxonomic position. The results indicate that the organism represents a new species, for which the name Mycobacterium novocastrense is proposed. MATERIALS AND METHODSOrganism and culture conditions. The organism (strain 73), which was isolated on Lowenstein-Jensen medium (9) after 9 weeks of growth at 36T, was obtained from a biopsy sample taken from a slowly spreading skin granulation on the hand of a six-year-old child. It was then cultivated on Columbia blood agar (4), Lowenstein-Jensen medium (9), MacConkey agar (IS), Middlebrook 7H10 agar (17), and 5% (wt/vol) sodium chloride agar (13) for between 3 and 10 days at 25°C and 36°C. The strain, which was maintained on Middlebrook 7H10 agar (17), was grown at 36°C in all of the remaining tests.Phenotypic characterization. The growth, temperature, and sensitivity studies were carried out on Middlebrook 7H10 agar (17). The Gram (16) and ZiehlNeelsen (20) stains were performed on cells grown for 5 days at 36°C on this medium. Catalase (14) and niacin (12) activity were examined after 10 days, and the production of arylsulfatase (29) was examined after 3 and 14 days. Similarly, iron uptake (27) and Tween hydrolysis (28) were detected after 10 days at 36°C.Extraction and analysis of mycolic acids. Lyophilized biomass from 10-day-old Middlebrook 7H10 agar plates was degraded by alkaline methanolysis (23) and two-dimensional thin-layer chromatography of the methanolysates carried out as described previously (19).Sequencing of genes coding for 16s rRNA (16s rDNA). The biomass of the test strain needed for sequencing was obtained from a 5-day-old Liiwenstein-Jensen (9) slant incubated at 36...

Summary. An artificial neural network (ANN) was trained to distinguish between Mycobacterium tuberculosis and M . bovis with averaged pyrolysis mass spectra from duplicate subcultures of four strains of each of these species, each pyrolysed in triplicate. Once trained, the ANN was interrogated with spectrum data from the original organisms (the "training set ") and from 26 other mycobacterial isolates (the "challenge set ") of the M . tuberculosis complex (MTBC). Eight strains of M . bovis and 13 of M . tuberculosis, whether sensitive or variously resistant to antituberculosis drugs, were identified in agreement with conventional identification. Four strains of " M . africanum" were identified as M . bovis. Of two atypical M . tuberculosis strains from South India, one was identified as M . tuberculosis and the other as M . bovis. Six strains of BCG proved heterogeneous; two gave equivocal identifications, three were identified as M . bovis and one was identified as M . tuberculosis.

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A strain isolated from a lung abscess in an elephant that died from chronic respiratory disease was found to have properties consistent with its classification in the genus Mycobacterium. An almost complete sequence of the 16S rDNA of the strain was determined following the cloning and sequencing of the amplified gene. The sequence was aligned with those available on mycobacteria and phylogenetic trees inferred by using three treemaking algorithms. The organism, which formed a distinct phyletic line within the evolutionary radiation occupied by rapidly growing mycobacteria, was readily distinguished from members of validly described species of rapidly growing mycobacteria on the basis of its mycolic acid pattern and by a number of other phenotypic features, notably its ability to grow at higher temperatures. The type strain is Mycobacterium elephantis DSM 44368 T .

Summary. The iron uptake mechanisms of enteropathogenic Escherichia coli (EPEC) were examined and compared with those of control E. coli strains. The incidence of aerobactin production was similar (39% and 37% respectively) in the two groups. The quantities of enterochelin produced by aerobactin-negative EPEC and control strains were similar, as were the quantities of enterochelin produced by aerobactin-positive EPEC and control strains. The ability to use haem or haemoglobin as an iron source in an iron-restricted environment was found in 80.4 % and 60.8 O h of EPEC strains respectively, and in 766 % and 56.6 % of control E. coli strains. The ability of E. coli strains to use these compounds was not related to the production of enterochelin or aerobactin or to the production of haemolysins, and may be an important characteristic of bowel organisms. When growing in an iron-limited environment, the iron contained in haemoglobin was used in preference to ovotransferrin-bound iron. During periods of haemoglobin-stimulated growth, the enterochelin uptake system was shown to be fully expressed and may be involved in transport of haemoglobin-derived iron into the cell. Uptake of ovotransferrin-bound iron took place immediately upon exhaustion of haemoglobin-derived iron. The ability to use iron derived from haem compounds represents an alternative iron uptake mechanism for organisms growing in an iron-limited environment and allows greater flexibility during growth in viuo.