Laura Otth

Susceptibility of Arcobacter butzleri to heavy metals

The susceptibility of 50 strains of Arcobacter butzleri isolated from chicken liver [12], mussels [18], river water [6] and bovine [5], duck [2] and pelicans [7] feces to mercury (Hg), chromium (Cr), silver (Ag), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo) and lead (Pb) was determined.All the strains were resistant to Mo, Mn, Ni, Co, Pb and Fe and susceptible to Hg, Ag and Cr. MIC values showed high variability, indicating a non homogeneous behavior among the strains.

Isolation of Helicobacter pylori in gastric mucosa and susceptibility to five antimicrobial drugs in Southern Chile

Helicobacter pylori colonizes more than 50% of the world population thus, it is considered an important cause of gastric cancer. The aim of this study was to determine the isolation frequency of H. pylori in Southern Chile from patients with symptomatology compatible with gastritis or gastric ulcer and to correlate these findings with demographic parameters of infected patients and the susceptibility profiles of the isolated strains to the antimicrobial drugs used in the eradication treatments. A total of 240 patients were enrolled in the study. Each gastric biopsy was homogenized and seeded onto blood agar plates containing a selective antibiotics mixture (DENT supplement). Plates were incubated at 37° C in a microaerophilic environment for five days. The susceptibility profiles to amoxicillin, ciprofloxacin, clarithromycin, tetracycline and metronidazole were determined using the E-test method. H. pylori was isolated from 99 patients (41.3%) with slightly higher frequency in female (42% positive cultures) than male (40.2% positive cultures). With regard to age and educational level, the highest isolation frequencies were obtained in patients between 21–30 (55%) and 41–50 (52.6%) years old, and patients with secondary (43.9%) and university (46.2%) educational levels. Nineteen (21.6%) strains showed resistance to at least one antimicrobial drug. Tetracycline was the most active antimicrobial in vitro, whereas metronidazole was the less active. One strain (5.3%) showed resistance to amoxicillin, clarithomycin and metronidazole, simultaneously.

Desiccation resistance in Arcobacter butzleri

The desiccation resistance of A. butzleri was studied. Two, 3 and 4 of the strains did not resist desiccation for more than 2, 12 and 36 h, respectively. Two strains resisted desiccation for > 48 h. A. butzleri seems to be more resistant to desiccation than the classical enteropathogenic Campylobacter species.

Actividad antibacteriana in vitro de propóleos chilenos sobre Helicobacter pylori

INTRODUCTION Propolis is a natural product derived from beekeeping. It has anesthetic, anti-inflammatory, immune-stimulant and antibacterial properties on grampositive and gramnegative bacteria. However, little is known regarding its activity on Helicobacter pylori. This bacteria colonizes about half of the worlds population and is associated with chronic gastritis, peptic ulcer and gastric cancer. OBJECTIVE The aim of this study was to evaluate the inhibitory activity of 22 propolis extracts from nine of the 11 beekeeping Chilean regions on 10 strains of H. pylori isolated from gastric mucosa. METHODS The antibacterial activity of the extracts was determined using the well diffusion method and diffusion disks. RESULTS 100% of the extracts were active on the tested strains, showing inhibition halos equal to or greater than 15 mm by both methods. CONCLUSIONS Our results show an effective anti H. pylori activity of propolis. However, additional microbiological studies are needed before a potential clinical utility of these natural products is warranted.

Antibiotic resistance in environmental Escherichia coli - a simple screening method for simultaneous typing and resistance determination.

We describe a simple and standardised screening system (AREB) for surveillance of antibiotic resistant bacteria in the environment. The system consists of 96 well microplates containing eight sets of breakpoint amounts of 10 different antibiotics. The incubated microplates are read by a desktop scanner and the plate images are analysed by special software that automatically presents the resistance data. The AREB method is combined with a rapid typing method, the PhenePlate system, which yields information on the diversity of the bacteria in the studied samples, and on the possible prevalence of resistant clones. In order to demonstrate the usage of AREB, a comparative study on the resistance situation among 970 Escherichia coli isolates from sewage and recipient water in Sweden, Norway and Chile, was performed. Resistance rates to all antibiotics were markedly higher in hospital sewage than in other samples. Our data indicate that the AREB system is useful for comparing resistance rates among E. coli and other environmental indicator bacteria in different countries/regions. Simple handling and automatic data evaluation, combined with low cost, facilitate large studies involving several thousands of isolates.

Susceptibility of Arcobacter butzleri to human blood serum.

, is a zoonotic bacterium isolated from mammals (dogs, cattle, monkeys, and swine) and domestic and wild birds (hens, turkeys, ducks, sparrows, and pelicans). It is recognized as an emerging enteric pathogen for human beings that could be also involved in extraintestinal infections such as bacteraemia and endocarditis (Kiehlbauch et al., 1991; Anderson et al., 1995; On et al., 1995; Jacob et al., 1998; Mansfield and Forsythe, 2000; Yan et al., 2000; Fernandez et al., 2007). Some of the virulence mechanisms of this bacterium have been studied, but the protective effects of normal serum and the role of complement in host defence remain to be evaluated. The protective effects of normal serum and the role of complement in host defence against invasive disease due to other enteropathogenic Gram negative bacteria, like

Antibodies anti-Chlamydia pneumoniae and anti-Mycoplasma pneumoniae in patients with negative serology for hantavirus. Retrospective study

The seroprevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in hantavirus seronegative patients, who had symptoms and signs compatible with pneumonia was established. For this purpose we used the indirect fluorescent antibody test. Titers > or = 1:16 for C. pneumoniae and M. pneumoniae were found in 8.6% and 17.1% of the serum, respectively, showing evidence of recent or current infection.

Subtyping of Chilean Methicillin-Resistant Staphylococcus aureus strains carrying the staphylococcal cassette chromosome mec type I

The cassette chromosome mec (SCCmec) present in methicillin-resistant Staphylococcus aureus (MRSA) has two essential components, the ccr gene complex and the mec gene complex. Additionally, SCCmec has non-essential components called J regions which are used for MRSA subtyping. This study was performed to determine subtypes MRSA strains carrying SCCmec type I based on polymorphism of regions located downstream of the mecA gene. A total of 98 MRSA strains carrying SCCmec type I isolated from patients hospitalized at the County Hospital of Valdivia (Chile) between May 2007 and May 2008, were analyzed by multiplex PCR designed to amplify the mecA gene and 7 DNA hypervariable regions located around the mecA gene. MRSA strains were classified into seventeen genotypes accordingly to amplification patterns of DNA hypervariable regions. Five genotypes showed amplification patterns previously described. The remaining twelve genotypes showed new amplification patterns. Genotypes 18 and Genotype 19 were the most frequently detected. Regions HVR, Ins117 and pI258 stand out as being present in more than 60% of tested isolates. The acquisition of hypervariable regions by MRSA is a continuous horizontal transfer process through which the SCCmec have been preserved intact, or even may give rise to new types and subtypes of SCCmec. Therefore it is possible to infer that most MRSA strains isolated at the County Hospital of Valdivia (Chile) were originated from two local clones which correspond to Genotype 18 and Genotype 19.

Asociación entre los criterios de clasificación genotípica de Staphylococcus aureus resistente a meticilina que se obtuvo mediante electroforesis en geles de campos pulsantes y mediante reacción en cadena de la polimerasa de regiones hipervariables del gen mecA

INTRODUCTION The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become a major epidemiological problem worldwide. METHODS We determined the degree of association between the genotype screening results obtained by pulse-field gel electrophoresis (PFGE) and polymerase chain reaction (PCR) for 7 hypervariable DNA regions associated with the mecA gene (HVR-mecA PCR), in the epidemiological analysis of 36 MRSA strains unrelated to nosocomial outbreaks, isolated from hospitalized patients at the County Hospital of Valdivia (Chile). RESULTS The strains were classified into 15 pulse types (A-O) and 5 genotypes (6, 14, 15, 16, and 17) by PFGE and HVR-mecA PCR, respectively. Most of the strains were grouped in pulse types D, E and I, which presented 85.7% similarity. The most common genotypes were 14 (36.1%) and 15 (33.3%). Each genotype detected by HVR-mecA PCR was distributed in more than one pulse type. The degree of association between genotypic screening by PFGE or HVR-mecA PCR was determined by calculating Cramers V statistic and the contingency coefficient. In both cases, a value near 1 (0.84 and 0.78, respectively) was obtained, indicating a high association between these genotypic screenings. Thus these are complementary, not exclusionary techniques that can be equally applied. CONCLUSIONS PFGE is a standardized, high-technology molecular tool with considerable discriminatory power. HVR-mecA PCR is a fast, simple, accessible tool that has lower discriminatory power; nonetheless it can serve as an alternative method for epidemiological research in MRSA strains.