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Biomedical subjects

R Cisterna

Publications and source records attributed to R Cisterna.

At least 19 recordsLinked to original sources

[Patterns of susceptibility to antibiotics of Enterobacteriaceae causing intra-abdominal infection in Spain: SMART 2003 study outcomes].

SMART (Study for Monitoring Antimicrobial Resistance Trends) is an ongoing global antimicrobial surveillance program focused on clinical isolates from intra-abdominal infections. The objective of this subanalysis was to assess antimicrobial susceptibility patterns among Entero-bacteriaceae recovered at 13 participating Spanish sites during 2003. Antimicrobial susceptibility testing was performed using broth microdilution techniques according to the CLSI (formerly NCCLS) guidelines for MIC testing. The presence of extended-spectrum beta-lactamases (ESBL) was confirmed in isolates with a MIC of ceftriaxone, ceftazidime, or cefepime>or=2 mg/l by comparing cefepime MICs with and with-out clavulanate. A total of 981 Enterobacteriaceae recovered from 840 patients were tested, of which 398 (41%) were community-acquired. Escherichia coli was the most common isolate (571 isolates; 58%), followed by Klebsiella spp. (153; 16% Enterobacter spp. (97; 10%), and Proteus spp. (63; 6%). A total of 191 isolates (19%) from 176 patients produced inducible beta-lactamases. The carbapenems and amikacin were the most consistently active agents against the Enterobacteriaceae (susceptibility>or=99%). Resistance rates for ceftazidime, cipro-floxacin, and levofloxacin exceeded 10%. ESBLs were detected phenotypically in 61 (6%) isolates, being the most common E. coli (61%), Klebsiella spp. (20%), and Enterobacter spp. (8%). Antimicrobial resistance among Enterobacteriaceae isolated from intra-abdominal infections is a problem in Spain. A significant proportion of inducible beta-lactamase and ESBL-producing Enterobacteriaceae causing intra-abdominal infection were acquired in the community. The carbapenems ertapenem, imipenem and meropenem and the aminoglycoside amikacin were highly active in vitro against Enterobacteriaceae isolated from intra-abdominal sites, including ESBL-producing organisms.

Abdomen↗

Orogenital transmission of Neisseria meningitidis serogroup C confirmed by genotyping techniques.

Urethritis caused by Neisseria meningitidis in heterosexual patients is presumed to occur via orogenital contact, but confirmation has not been possible in most cases. Presented here is a case of urethritis caused by N. meningitidis, serogroup C, and the isolation of the same microorganism from the nasopharynx and endocervix of the patient's sexual partner. The similarity of the urethral and nasopharyngeal isolates' electrophoretic patterns, obtained using pulsed-field gel electrophoresis, proves the infection was transmitted via orogenital contact.

Adult↗

[Hepatitis C virus variability and interferon-mediated pathway inhibition].

The most important aim of this study was to describe the hypothetical relationship between the PePHD region variability (related to the synthesis of a cellular enzyme pseudosubstrate) of the hepatitis C virus and the response of patients to interferon therapy. This interaction could be a determining factor in the antiviral effect of interferon. All samples (from 24 patients with chronic hepatitis C infection) were analyzed using a previously described method based on RT-PCR and nested PCR mediated by single-strand conformation polymorphism assay (SSCP). The patients were divided into three groups with respect to the response to therapy: 8 patients with sustained response, 8 patients with transient response and 8 nonresponders. In all samples a low genetic heterogeneity pattern was detected, which was independent of other factors involved in the lack of response to treatment, such as age, sex or viral genotype. This genetic homogeneity is an indirect indication of the importance of the region on viral persistence. However, more studies are needed to evaluate the real role of this sequence on the interaction between cells and the virus.

Adult↗

Non-radioactive PCR-SSCP with a single PCR step for detection of inhibitor resistant beta-lactamases in Escherichia coli.

A method based on PCR-SSCP has been developed to detect presumptive Inhibitor-Resistant TEM (IRT) beta-lactamases in Escherichia coli. The capacity of this technique to differentiate genes from 11 control strains encoding IRT beta-lactamases was evaluated with PCR products digested with RsaI. All the bla(TEM) genes studied could be distinguished by their electrophoretic mobilities. Applied to 29 epidemiologically unrelated clinical isolates of E. coli resistant to amoxicillin-clavulanate (MIC, > or =32 microg/ml), the electrophoretic mobilities of the digested bla(TEM) PCR products were identical to those of the reference bla(TEM-1A) (6 strains) and bla(TEM-1B) (18 strains) genes. The remaining five bla(TEM) PCR products displayed SSCP profiles different from those of the reference bla(TEM) genes and their nucleotide sequence identified them as bla(TEM-1C) in one strain, bla(TEM-30/IRT-2) in two strains, bla(TEM-37/IRT-8) in one strain, and bla(TEM-40/IRT-11) in one isolate. Overexpression of the wild-type bla(TEM-1) gene, as detected by high-level resistance to beta-lactams and enzyme assay, accounted for resistance in the 24 E. coli containing bla(TEM-1). We report a simple one PCR step SSCP that can be used in epidemiological studies for rapid preliminary detection of IRT beta-lactamases; identification should be confirmed by sequence data.

Amoxicillin↗

[Viral quasispecies and their implications in antiviral therapy].

The aim of this study was to evaluate the relationship between the quasispecies in the HVR1 region of the hepatitis C virus and treatment evolution in order to determine whether genetic complexity is predictive of response to interferon therapy. The samples were analyzed by nested RT-PCR-mediated single-strand conformation polymorphism assay (SSCP). Twelve patients with chronic hepatitis C were studied and divided into three groups: three patients with sustained response, three patients with transient response and six nonresponders. The patients in the sustained response group showed a low genetic complexity pattern. By contrast, in three nonresponders and in one patient with transient response, the SSCP assay revealed a high complexity pattern. With regard to the remaining patients with transient response, new SSCP bands appeared, thereby modifying their genetic complexity pattern. Therefore, nonresponse to interferon treatment could be related to the presence of a high genetic complexity pattern, while the detection of a low genetic complexity pattern is necessary for a positive response to interferon therapy. Due to the limited number of patients involved in this study, it was not possible to predict the response to interferon based on the genetic complexity pattern. Larger studies are therefore required.

Antiviral Agents↗

[Detection of syncytial respiratory virus in clinical samples using a RT-PCR technique].

From November 2000 to May 2001, 208 clinical samples were analyzed for respiratory infection. Parallel to the detection of the syncytial respiratory virus (SRV) by solid phase immunoassay (EIA) and rapid culture in shell-vial or conventional tube, a reverse transcription polymerase chain reaction (RT-PCR) technique was developed. The procedures were complimentary and useful in the diagnosis of respiratory infections due to SRV, both in children and adults.

Humans↗

[Community-acquired bacteremia].

Bacteremia continues to be one of the main causes of mortality despite the existence of numerous antimicrobial agents and an increase in means of support. A variety of factors, such as the type of microorganism, age, the underlying disease and where the bacteremia was acquired, can change the prognosis of the infection. The aim of this study was to analyze the cases of community-acquired bacteremia gathered prospectively from the Basurto hospital in Bilbao, Spain. The incidence of bacteremia was estimated using preestablished protocol (SEPSIS-DATA) from January 1994 to September 2001. Information was gathered on all the cases of bacteremia at the hospital and only those which were of non-hospital origin (2886 cases) were selected for the study. In our hospital, 67.82% of the bacteremia cases were community-acquired, a figure which remained stable throughout the 8-year study period. A total of 54.64% of the patients were male, 1603 (55.54%) of whom were over age 60 years. The most common underlying diseases were diabetes (15.75%), neoplasia (14.96%) and HIV infection (12.9%). The majority of the cases (2216, 76.8%) were admitted to the general medicine ward, 335 (11.6%) to surgery, 200 (6.9%) to pediatrics and 135 (4.67%) to ICU. The origin of the bacteremia was urinary (33%), gastrointestinal (18%) or respiratory (18.26%). The most common microorganisms were E. coli (36%), S. pneumoniae (13%), S. aureus (9.46%), S. enteritidis (2.87%), P. aeruginosa (2.71%), P. mirabilis (2.65%) and N. meningitidis (2.45%). The bacteremia was polymicrobial in 6.27% of the cases. The most used antibiotics were ceftriaxone (31%), gentamicin (7.3%) and amoxicillin-clavulanic acid (6.9%). Overall mortality was 13.82%. The relative frequency of community-acquired/nosocomial infection remained stable in two-thirds of the total cases. The incidence of bacteremia decreased in the 20-40 year age group and in those with HIV infection. E. coli and S. pneumoniae increased, while S. aureus decreased. The use of imipenem and quinolones increased. E. coli resistance to quinolones increased from 3.54% in 1995 to 14.36% in 2000. Mortality decreased slightly, with no significant differences.

Adolescent↗

Specific and rapid identification of multiple-antibiotic resistant Pseudomonas aeruginosa clones isolated in an intensive care unit.

Seventeen multiple-antibiotic-resistant Pseudomonas aeruginosa isolates were collected from two patients hospitalized in the same intensive care unit. They showed a parallel acquisition of resistance to antibiotics and they were, therefore, thought to have a common clonal origin. These strains were typed by biotyping, serotyping, plasmid profile, three different PCR-based techniques, and macrorestriction analysis to determine their relationship. Only the use of PCR techniques and macrorestriction analysis allowed an accurate identification of the clones and revealed that each patient was infected by A unique multidrug-resistant strain. Therefore, there was no cross-infection or reinfection with a new strain.

Anti-Bacterial Agents↗

[RT-PCR for the determinationof the type of influenza virus circulating in the population].

Reverse transcription polymerase chain reaction (RT-PCR) was used to determine the type of flu virus that was circulating mostly in the population of the Basque Country in the 1999-2000 season. In this time period, 124 nasal and pharyngeal aspirations from persons with flu-like symptoms were analyzed. A parallel analysis was carried out using a conventional culture or a shell-vial in MDCK cell line, and immunofluorescence and multiple RT-PCR for the detection of influenza virus and its A and B types. Of the samples studied, 57 (45.96%) were positive for type A by the culture method and 64 (51. 61%) by RT-PCR of a genomic region that codifies the non-structural proteins NS1 and NS2. We also developed a rapid-detection method in which the transcription and amplification are carried out in a single step, using the same mix of transcription-amplification. Based on the results we can conclude that RT-PCR is a very sensitive method for the detection of the flu virus; we believe that its sensitivity, combined with its rapidity, makes it ideal for the detection of these respiratory viruses and the analysis of strains circulating in the population.

Cell Line↗

[Profile of bacterial isolates and antimicrobial susceptibility: Multicenter study using a one-day cut-off].

The frequency and antimicrobial susceptibility of bacterial isolates from the largest clinical samples collected in 19 Spanish hospitals were studied. A total of 523 strains were identified and grouped by sample. Blood stream: Staphylococcus coagulase-negative (41%) and Escherichia coli (19.7%); oxacillin resistance occurred in 44% of coagulase-negative strains, strains which were also resistant to nonbetalactam agents. All antimicrobial agents tested had good activity against E. coli, with the exception of penicillins (25 to 33% susceptible). Urine: E. coli (59.1%) and Enterococcus faecalis (15%); aminoglycosides and third generation cephalosporins were the most active compounds against E. coli, whereas penicillins and cotrimoxazole were the least active. E. faecalis isolates showed low rates of resistance to the antibiotics tested and no glycopeptide-resistant strains were detected. Skin and soft tissues: Staphylococcus aureus (24.1%), Pseudomonas aeruginosa (17.7.%); oxacillin resistance occurred in 15.8% of S. aureus strains and co-resistance to nonbetalactam agents was frequently observed among these strains. Ceftazidime susceptibility was elevated among P. aeruginosa (76.9%) and the most active agents were aminoglycosides (100% susceptibility). Lower respiratory tract: P. aeruginosa (21.4%) and Haemophilus influenzae (15.5%). Aminoglycosides (88.8 to 94.4%) and ceftazidime (72%) presented the highest susceptibility rates in P. aeruginosa. All the agents tested were very active against H. influenzae (89% susceptibility). Among Gram-positive cocci, no vancomycin and/or teicoplanin-resistant strains were detected.

Bacterial Infections↗