title: Detecting the presence of bacterial DNA by PCR can be useful in diagnosing culture-negative cases of infection, especially in patients with suspected infection and antibiotic therapy.
abstract: Failing in bacteria isolation in a significant number of infections might be due to the involvement of microorganisms nonrecoverable in culture media. The presence cannot be ruled out of nondividing cells or even bacterial products still capable of promoting a host immunological response. Antibiotic therapy, for example, might induce a block of bacterial division and the impossibility of recovering cells in culture media. In these cases, a molecular method targeting DNA should be used. In this study, 230 clinical samples with a culture-negative report obtained from 182 patients were examined with a protocol of PCR targeting the bacterial 16S rRNA gene to evaluate the usefulness of molecular methods in differencing culture-negative infections from other pathologies. Amplicons were obtained in 14% of the samples, although this percentage increased (27%) in a subgroup of patients with presumptive diagnosis of infection and ongoing antibiotic therapy. By multiplex PCR, it was shown that detected DNA belonged mostly to Enterobacteriaceae and enterococcal species. Multiple culture-negative, PCR-positive samples and isolation of the same bacterial species in culture in additional samples from the same patient support the clinical significance of the data obtained and highlight the complementary role and usefulness of applying molecular methods in diagnostic microbiology.
authors.affiliation: Dipartimento di Patologia e Diagnostica, Sezione di Microbiologia, Università di Verona, Verona, Italy.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Lleo
authors.forename: Valentina
authors.initials: V
authors.lastname: Ghidini
authors.forename: Maria Carla
authors.initials: MC
authors.lastname: Tafi
authors.forename: Francesco
authors.initials: F
authors.lastname: Castellani
authors.forename: Ilaria
authors.initials: I
authors.lastname: Trento
authors.forename: Marzia
authors.initials: M
authors.lastname: Boaretti
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000175:diagnosis* / Q000188:drug therapy* / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics*; D003955:Diagnostic Tests, Routine / Q000379:methods*; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial
keywords: DNA in culture-negative clinical samples; bacterial survival strategies; nonculturable bacteria in human infections