Almost all of the multiresistant pneumococci that appeared suddenly in clinical specimens in Iceland between 1989 and 1992 belonged to serogroup 6. Fifty-seven of these isolates were analyzed for serotype, penicillin-binding protein pattern, multilocus enzyme genotype, and fragmentation pattern obtained by pulsed-field electrophoretic separation of restriction enzyme digests of chromosomal DNA. All isolates were of serotype 6B and had similar or identical patterns in each molecular test. The Icelandic isolates were indistinguishable from a subgroup of multiresistant serotype 6B pneumococci that has been present with high incidence in Spain during the past two decades. The data suggest the import to Iceland of a single multiresistant clone of pneumococcus, most likely from Spain.

The Bacillus subtilis L-arabinose (ara) operon : nucleotide sequence, genetic organization and expression The Bacillus subtilis L-arabinose metabolic genes araA, araB and araD, encoding L-arabinose isomerase, L -r i bulokinase and ~-ribulose-5-phosphate 4-epimerase, respectively, have been cloned previously and the products of araB and araD were shown to be functionally homologous to their Escherichia coli counterparts by complementation experiments. Here we report that araA, araB and araD, whose inactivation leads to an Ara' phenotype, are the first three ORFs of a nine cistron transcriptional unit with a total length of 11 kb. This operon, called ara, is located at about 256" on the B. subtilis genetic map and contains six new genes named araL, araM, araN, araP, araQ and abfA. Expression of the ara operon is directed by a strong &like promoter identified within a 150 bp DNA fragment upstream from the translation start site of araA. Analysis of the sequence of the ara operon showed that the putative products of araN, araP and araQ are homologous to bacterial components of binding-protein-dependent transport systems and abfA most probably encodes an a-L-arabinofuranosidase. The functions of araL and araM are unknown. An in vitro-constructed insertion-deletion mutation in the region downstream from araD allowed us to demonstrate that araf, araM, araN, araP, araQ and abfA are not essential for L-arabinose utilization. Studies with strains bearing transcriptional fusions of the operon to the E. coli lacZ gene revealed that expression from the ara promoter is induced by L-arabinose and repressed by g I ucose.

SummaryThe resurgence of tuberculosis and the emergence of multidrug-resistant mycobacteria necessitate the development of new antituberculosis drugs. The biosynthesis of mycolic acids, essential elements of the mycobacterial envelope, is a good target for chemotherapy. Species of the Mycobacterium tuberculosis complex synthesize oxygenated mycolic acids with keto and methoxy functions. In contrast, the fastgrowing Mycobacterium smegmatis synthesizes oxygenated mycolic acids with an epoxy function. We describe the isolation and sequencing of a cluster of four genes from Mycobacterium bovis bacillus Calmette-Gué rin (BCG), coding for methyl transferases, and which, when transferred into M. smegmatis, allow the synthesis of ketomycolic acid, in addition to an as yet undescribed mycolic acid, hydroxymycolic acid. These oxygenated mycolic acids, unlike the regular mycolic acids of M. smegmatis, and similar to the mycolic acids of M. bovis, are highly cyclopropanated. Furthermore, there is a perfect match between the structures of the keto-and the hydroxy-mycolic acids. We propose a biosynthetic model in which there is a direct relationship between these two types of mycolic acid.

Surveillance for nasopharyngeal colonization with Streptococcus pneumoniae was maintained in a research day care center between 1985 and 1992. An outbreak of nasal carriage of a multi-drug-resistant (MDR) serotype 23F organism occurred between May 1990 and December 1991 involving 14 of 52 children. Electrophoresis of penicillin-binding proteins (PBP) and pulsed-field gel electrophoresis (PFGE) of chromosomal DNA indicated that the MDR serotype 23F organism was closely related to a serotype 23F MDR clone that has been prevalent in Spain since the early 1980s. In June 1991, an MDR serotype 14 organism was isolated from a child who had previously carried the MDR serotype 23F strain. PFGE and PBP typing revealed that the MDR serotype 14 organism was very similar to the circulating MDR serotype 23F strain, suggesting serotype transformation. Dissemination of MDR pneumococcal strains and possibly spread of the MDR phenotype to additional serotypes may be facilitated in group day care.

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