Marianne Gunell

In Vitro Activity of Azithromycin against Nontyphoidal Salmonella enterica

ABSTRACT The in vitro activity of azithromycin against 1,237 nontyphoidal Salmonella enterica isolates collected from Finnish patients between 2003 and 2008 was investigated. Only 24 (1.9%) of the isolates tested and 15 (5.1%) of the 294 isolates with reduced fluoroquinolone susceptibility had azithromycin MICs of ≥32 μg/ml. These data show that azithromycin has good in vitro activity against nontyphoidal S. enterica, and thus, it may be a good candidate for clinical treatment studies of salmonellosis.

Cefotaxime-Resistant Salmonella enterica in Travelers Returning from Thailand to Finland

During 1993–2011, cefotaxime resistance among Salmonella enterica isolates from patients in Finland increased substantially. Most of these infections originated in Thailand; many were qnr positive and belonged to S. enterica serovar Typhimurium and S. enterica monophasic serovar 4,[5],12:i:-. Although cefotaxime-resistant salmonellae mainly originate in discrete geographic areas, they represent a global threat.

Prevalence of Complications Leading to a Health Care Contact After Transrectal Prostate Biopsies: A Prospective, Controlled, Multicenter Study Based on a Selected Study Cohort

BACKGROUND Transrectal ultrasound-guided prostate biopsy (TRUS-Bx) is typically considered a safe procedure. However, infectious complications have been increasing. OBJECTIVE To determine the contemporary rate of biopsy-related infectious and noninfectious complications after TRUS-Bx, and identify potential risk factors associated with the complications. DESIGN, SETTING, AND PARTICIPANTS This was a prospective multicenter study and a substudy of a trial investigating the role of magnetic resonance imaging (MRI) in prostate cancer diagnosis (multi-IMPROD, NCT02241122). INTERVENTION TRUS-Bx was performed for all patients included in the study. Ciprofloxacin, levofloxacin, or fosfomycin was administered for antibiotic prophylaxis. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS On inclusion, patients completed a detailed questionnaire and underwent MRI scanning. Antibiotic prophylaxis was prospectively recorded. After collection of a rectal swab, TRUS-Bx (total of 14-18 biopsy cores) was performed and. The rectal swabs were cultured and the antimicrobial susceptibility profile of Escherichia coli strains was analyzed. Biopsy complications leading to a visit to a health care unit were recorded and potential risk factors for complications were analyzed. RESULTS AND LIMITATIONS Twelve of the 294 patients (4.1%) had a biopsy-related complication, of which two (0.7%) were infectious and managed in the outpatient setting. Some 11% of the patients had an E. coli strain resistant to the prophylactic antibiotic administered. CONCLUSIONS The risk of an infectious or noninfectious complication after TRUS-Bx is very low, although the FQ resistance rate in the study population was significant. Accordingly, the present TRUS-Bx procedure and antibiotic prophylaxis are efficient in guarding against biopsy complications, but regional resistance rates may affect the generalizability of the results. PATIENT SUMMARY We examined the rate of complications after prostate biopsies in 294 patients. The risk of having a biopsy-related complication was low (4.1%). The rate of infectious complications was reasonably low (0.7%) although antibiotic resistance to the prophylactic antibiotic regimen was significant (11%).

Mechanisms of resistance in non-typhoidal Salmonella enterica exhibiting a non-classical quinolone resistance phenotype

ABSTRACT Nontyphoidal Salmonella enterica strains with a nonclassical quinolone resistance phenotype were isolated from patients returning from Thailand or Malaysia to Finland. A total of 10 isolates of seven serovars were studied in detail, all of which had reduced susceptibility (MIC ≥ 0.125 μg/ml) to ciprofloxacin but were either susceptible or showed only low-level resistance (MIC ≤ 32 μg/ml) to nalidixic acid. Phenotypic characterization included susceptibility testing by the agar dilution method and investigation of efflux activity. Genotypic characterization included the screening of mutations in the quinolone resistance-determining regions (QRDR) of gyrA, gyrB, parC, and parE by PCR and denaturing high-pressure liquid chromatography and the amplification of plasmid-mediated quinolone resistance (PMQR) genes qnrA, qnrB, qnrS, qnrD, aac(6′)-Ib-cr, and qepA by PCR. PMQR was confirmed by plasmid analysis, Southern hybridization, and plasmid transfer. No mutations in the QRDRs of gyrA, gyrB, parC, or parE were detected with the exception of a Thr57-Ser substitution within ParC seen in all but the S. enterica serovar Typhimurium strains. The qnrA and qnrS genes were the only PMQR determinants detected. Plasmids carrying qnr alleles were transferable in vitro, and the resistance phenotype was reproducible in Escherichia coli DH5α transformants. These data demonstrate the emergence of a highly mobile qnr genotype that, in the absence of mutation within topoisomerase genes, confers the nontypical quinolone resistance phenotype in S. enterica isolates. The qnr resistance mechanism enables bacteria to survive elevated quinolone concentrations, and therefore, strains carrying qnr alleles may be able to expand during fluoroquinolone treatment. This is of concern since nonclassical quinolone resistance is plasmid mediated and therefore mobilizable.

Antibiotic susceptibility of intestinal Escherichia coli in men undergoing transrectal prostate biopsies: a prospective, registered, multicentre study

To determine, in a prospective, multicentre setting, the prevalence of fluoroquinolone‐resistant (FQ‐R) and extended‐spectrum β‐lactamase (ESBL)‐producing Escherichia coli (E. coli) strains in men undergoing transrectal ultrasonography‐guided prostate biopsy (TRUS‐Bx) in Finland; and to survey the associated risk factors for having the previously mentioned strains.

Antimicrobial characterization of silver nanoparticle-coated surfaces by “touch test” method

Bacterial infections, especially by antimicrobial resistant (AMR) bacteria, are an increasing problem worldwide. AMR is especially a problem with health care-associated infections due to bacteria in hospital environments being easily transferred from patient to patient and from patient to environment, and thus, solutions to prevent bacterial transmission are needed. Hand washing is an effective tool for preventing bacterial infections, but other approaches such as nanoparticle-coated surfaces are also needed. In the current study, direct and indirect liquid flame spray (LFS) method was used to produce silver nanoparticle-coated surfaces. The antimicrobial properties of these nanoparticle surfaces were evaluated with the “touch test” method against Escherichia coli and Staphylococcus aureus. It was shown in this study that in glass samples one silver nanoparticle-coating cycle can inhibit E. coli growth, whereas at least two coating cycles were needed to inhibit S. aureus growth. Silver nanoparticle-coated polyethylene (PE) and PE terephthalate samples did not inhibit bacterial growth as effectively as glass samples: three nanoparticle-coating cycles were needed to inhibit E. coli growth, and more than 30 coating cycles were needed until S. aureus growth was inhibited. To conclude, with the LFS method, it is possible to produce nanostructured large-area antibacterial surfaces which show antibacterial effect against clinically relevant pathogens. Results indicate that the use of silver nanoparticle surfaces in hospital environments could prevent health care-associated infections in vivo.

Mechanisms of Resistance in Nontyphoidal Salmonella enterica Strains Exhibiting a Nonclassical Quinolone Resistance Phenotype

ABSTRACT Nontyphoidal Salmonella enterica strains with a nonclassical quinolone resistance phenotype were isolated from patients returning from Thailand or Malaysia to Finland. A total of 10 isolates of seven serovars were studied in detail, all of which had reduced susceptibility (MIC ≥ 0.125 μg/ml) to ciprofloxacin but were either susceptible or showed only low-level resistance (MIC ≤ 32 μg/ml) to nalidixic acid. Phenotypic characterization included susceptibility testing by the agar dilution method and investigation of efflux activity. Genotypic characterization included the screening of mutations in the quinolone resistance-determining regions (QRDR) of gyrA, gyrB, parC, and parE by PCR and denaturing high-pressure liquid chromatography and the amplification of plasmid-mediated quinolone resistance (PMQR) genes qnrA, qnrB, qnrS, qnrD, aac(6′)-Ib-cr, and qepA by PCR. PMQR was confirmed by plasmid analysis, Southern hybridization, and plasmid transfer. No mutations in the QRDRs of gyrA, gyrB, parC, or parE were detected with the exception of a Thr57-Ser substitution within ParC seen in all but the S. enterica serovar Typhimurium strains. The qnrA and qnrS genes were the only PMQR determinants detected. Plasmids carrying qnr alleles were transferable in vitro, and the resistance phenotype was reproducible in Escherichia coli DH5α transformants. These data demonstrate the emergence of a highly mobile qnr genotype that, in the absence of mutation within topoisomerase genes, confers the nontypical quinolone resistance phenotype in S. enterica isolates. The qnr resistance mechanism enables bacteria to survive elevated quinolone concentrations, and therefore, strains carrying qnr alleles may be able to expand during fluoroquinolone treatment. This is of concern since nonclassical quinolone resistance is plasmid mediated and therefore mobilizable.