RESUMO
This study aimed to investigating the possible interference caused by glass test tubes on the quantification of bacterial adhesion to hydrocarbons by the MATH test. The adhesion of four bacteria to hexadecane and to glass test tubes was evaluated employing different suspending polar phases. The role of the ionic strength of the polar phase regarding adhesion to glassware was investigated. Within the conditions studied, Gram-positive bacteria adhered to both the test tube and the hydrocarbon regardless of the polar phase employed; meanwhile, Escherichia coli ATCC 25922 did not attach to either one. The capacity of the studied microorganisms to adhere to glassware was associated with their electron-donor properties. The ionic strength of the suspending media altered the patterns of adhesion to glass in a strain-specific manner by defining the magnitude of electrostatic repulsion observed between bacteria and the glass surface. This research demonstrated that glass test tubes may interact with suspended bacterial cells during the MATH test under specific conditions, which may lead to overestimating the percentage of adhesion to hydrocarbons and, thus, to erroneous values of cell surface hydrophobicity.
Assuntos
Aderência Bacteriana , Vidro , Vidro/química , Escherichia coli , Alcanos/química , Concentração Osmolar , Interações Hidrofóbicas e Hidrofílicas , Hidrocarbonetos/metabolismo , Bactérias Gram-Positivas/isolamento & purificaçãoRESUMO
Bacterial cell surface hydrophobicity is a relevant property in determining the ability of bacteria to adhere to inert surfaces. This property has been measured using the microbial adhesion to hydrocarbon (MATH) test. Several reports in the literature establish the percentage of adhesion to hydrocarbons (PoAtH) value produced by the MATH test for a broad variety of bacteria. Discrepancies in PoAtH values reported for the same strain of a specific microorganism suggest that some method-induced variation may exist, as different research teams employ different versions of the assay. The objective of the present study was to compare the performance of different versions of the MATH test as reported in the literature, to quantify the magnitude of the method-induced variation on PoAtH values. The study demonstrated that PoAtH values are influenced twice as much by variations in the employed assay than by actual differences in cell surface composition or architecture. The two L. reuteri strains studied responded differently to changes in assay conditions showing 40 and 70% method-dependent variation for strain ATCC 53609 and 55730, respectively. These results highlight the need to properly standardize the MATH test to enable comparison of PoAtH values produced by independent research teams.
Assuntos
Aderência Bacteriana , Bioensaio/métodos , Membrana Celular/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Humanos , Hidrocarbonetos/metabolismo , Limosilactobacillus reuteri , TemperaturaRESUMO
European foulbrood (EFB) caused by Melissococcus plutonius is an important bee brood disease but, in Mexico, information about this bacterium is limited. We evaluated the prevalence of typical and atypical strains in beehives of seven apicultural regions of the state of Chihuahua, Mexico. We performed MLST and phylogenetic analysis to characterize the isolates. Prevalence was highest 59%, in the region of Chihuahua, and lowest, 14%, in the regions of Cuauhtémoc and Nuevo Casas Grandes. Typical and atypical strains were identified in hives from all regions; however, in the regions of Parral, Cuauhtémoc and Aldama, the atypical strains were only detected in combination with typical strains. We obtained 81 isolates of M. plutonius and identified seven sequence types, of which three were new types. Additionally, we observed a relation between sequence type and the region where the strain was isolated. Phylogenetic analysis and multilocus sequence typing using goeBURST analysis showed that 97.5% of the isolates correspond to the Clonal Complex (CC) 12 and 2.5% to the CC3. Our work is the first molecular characterization of M. plutonius in Mexico and contributes to global information about the epidemiology of this pathogen.