Evidenziazione molecolare di resistenza di Mycobacterium tuberculosis complex a rifampicina e isoniazide

From June 2004 to June 2005, a total of 58 mycobacterial isolates were recovered from inpatients admitted to the “Ospedale Maggiore” in Novara, Italy. Most of the above strains were from respiratory secretions. Among the 32 isolates identified as Mycobacterium tuberculosis complex (MTC), susceptibility testing to streptomycin, isoniazid, rifampin, ethambutol and pyrazinamide was subsequently performed by using the MGIT 960 system. Starting from positive cultures, the Genotype MTBDR “Arnika” test, based on target amplification and stripbased reverse hybridization was also carried out. In addition to the MTC identification, the test can investigate the resistance to both rifampin (by molecular analysis of the rpoB region) and isoniazid (by detecting mutations at the resistance domain of katG gene). The results were compared with those obtained by conventional liquid medium susceptibility testing. Full agreement with both drugs was obtained on all the tested isolates. In conclusion, the GenoType MTBDR assay was found to enable a very rapid resistance detection of the most important anti-tubercular drugs.These data are important to set up an effective therapy and consequent disease control

Incidence of Chlamydia trachomatis infections in the provinces of Novara and VCO: one year of observations

Chlamydia trachomatis infections represent the most common sexually transmitted diseases.The lack of growth of these microorganisms on common media and the roundabout research by immunofluorescence, has meant that, until now, these special-lived intracellular microorganisms have played a role probably underestimated in cases of infections affecting the sexual organs.The introduction of molecular biology has made possible their research in a much more simple, reliable and standardized methods. The study was carried out on endocervical samples, male urethral swabs and urine samples of men and women, determining the C. trachomatis DNA amplified using the BD ProbeTec ET system. This system uses technology SDA (Strand Displacement Amplification - Elongationcrowding of the blanks). The study was conducted from June 2008 to june 2009. Symptomatic and asyntptomatic patients residents in the provinces of Novara and the Verbano-Cusio-Ossola were considered. In this period 784 determinations were made in molecular biology. Chlamydia trachomatis was found in 26 cases equal to a percentage of 3.32%. While considering these preliminary data, however, we can estimate the rate of detection of C. trachomatis as a good starting point, because we have the impression that improved procedures particularly relate to the techniques for sampling and for storage and transport of the sample, can undoubtedly lead to much higher percentages

Mycobacterium szulgai: articular infections case report

Introduction: The bone and joint infections sustained by mycobacteria and mainly involving the synovium, tendons and bone stock, may be traumatic, especially in open fractures or iatrogenic post surgical procedures. Methods: The frustules, taken after cleaning the bone, were sent to the Microbiological Laboratory and processed for the presence of Gram-positive and Gram-negative bacterial populations, the mycobacteria Group M. tuberculosis complex and the mycobacteria belonging to the group of NTM (Non Tubercular Mycobacteria). Results: The decontaminated material was sown on liquid culture (MGIT 960 System BD Diagnostics) and on solid growth medium (Löwenstein-Jensen) and kept under observation at 37° C for 60 days. After 15 days on the solid medium there developed a mycobacterium strongly pigmented in orange. By the reverse hybridization method “GenoType® CM; Hain Diagnostika, Nehren, Germany; Arnika”, Mycobacterium szulgai was identified, an organism rarely isolated in our laboratory. On preliminary characterization it resulted scotochromogenic at 37° C and photochromogenic when cultured at 25° C. Conclusions: The isolation of M. szulgai, and the previous isolation of a M. intracellular (paper in press) from a similar material suggest that, in this type of infection, the role of mycobacteria can be clinically relevant and probably underestimated, both because the difficulty of isolating and identifying these organisms and because surgeons almost never request this type of investigation. It would therefore be appropriate to send routinely these materials to dedicated laboratories equipped to search for mycobacteria. Its identification could allow a more realistic picture on the role played by these bacterial infections in osteoarticular infections

Mycobacterium celeriflavum sp nov., a rapidly growing scotochromogenic bacterium isolated from clinical specimens

Six strains of a rapidly growing scotochromogenic mycobacterium were isolated from pulmonary specimens of independent patients. Biochemical and cultural tests were not suitable for their identification. The mycolic acid pattern analysed by HPLC was different from that of any other mycobacterium. Genotypic characterization, targeting seven housekeeping genes, revealed the presence of microheterogeneity in all of them. Different species were more closely related to the test strains in various regions: the type strain of Mycobacterium moriokaense showed 99.0% 16S rRNA gene sequence similarity, and 91.5-96.5% similarity for the remaining six regions. The whole genome sequences of the proposed type strain and that of M. moriokaense presented an average nucleotide identity (ANI) of 82.9%. Phylogenetic analysis produced poorly robust trees in most genes with the exception of rpoB and sodA where Mycobacterium flavescens and Mycobacterium novocastrense were the closest species. This phylogenetic relatedness was confirmed by the tree inferred from five concatenated genes, which was very robust. The polyphasic characterization of the test strains, supported by the ANI value, demonstrates that they belong to a previously unreported species, for which the name Mycobacterium celeriflavum sp. nov. is proposed. The type strain is AFPC-000207(T) (=DSM 46765(T)=JCM 18439(T))