Bacterial communities of big-headed ants (Pheidole rugaticeps) and American cockroaches (Periplaneta americana) revealed pathogens of public health importance

Aims@#Several cockroach and ant species have been revealed to infest households with inadequate insect control and food storage practices. These household insects harbor countless bacteria species of public health, agricultural and industrial importance. Many studies have reported disease-causing bacteria from both cockroaches and ant’s species collected from hospitals and residential areas. The aim of this study was to characterize the culturable bacterial communities of two common household insects, big headed ants (Pheidole rugaticeps) and American cockroaches (Periplaneta americana) using 16S rRNA genes sequencing.@*Methodology and results@#A total of 64 bacterial sequences were obtained from P. rugaticeps (48.44%) and P. americana (51.56%) and Firmicutes was the most dominant phylum from both insect species. Bacillus was the most dominant bacterial genus from both cockroach and ant samples. Other important genera isolated were Pseudomonas and Stenotrophomonas which have previously been suggested to have members that are of biotechnological importance. Food poisoning bacterial species, B. cereus and other bacterial strains such as B. subtilis, Acinetobacter baumannii, Burkholderia cepacia, P. aeruginosa, Staphylococcus epidermidis, Serratia marcescens and S. pseudintermedius with the history of human infections were isolated from some of the insect’s specimens.@*Conclusion, significance and impact of study@#Thus, these household insect pests harbor bacterial species known to cause diseases of serious public health importance that needs serious attentions. Similarly, the insects harbor other bacteria species that may provide opportunities for biotechnological exploration.

Advance in study on 16S rRNA gene sequencing technology in oral microbial diversity / 中南大学学报(医学版)

The 16S rRNA gene is the most commonly used molecular marker for identifying microorganisms. It is used in sequencing technology, including the first-generation, the second-generation, and the third-generation sequencing technology. A large number of studies on the 16S rRNA gene have contributed to a deeper understanding of oral microbial diversity. In the healthy oral cavity, there is microbial diversity in time and space. With the occurrence or development of oral diseases such as caries, periodontal disease, or halitosis, the microbial diversity will be changed.

Effect of sulfonylurea tribenuron methyl herbicide on soil Actinobacteria growth and characterization of resistant strains

ABSTRACT Repeated application of pesticides disturbs microbial communities and cause dysfunctions on soil biological processes. Granstar® 75 DF is one of the most used sulfonylurea herbicides on cereal crops; it contains 75% of tribenuron-methyl. Assessing the changes on soil microbiota, particularly on the most abundant bacterial groups, will be a useful approach to determine the impact of Granstar® herbicide. For this purpose, we analyzed Actinobacteria, which are known for their diversity, abundance, and aptitude to resist to xenobiotic substances. Using a selective medium for Actinobacteria, 42 strains were isolated from both untreated and Granstar® treated soils. The number of isolates recovered from the treated agricultural soil was fewer than that isolated from the corresponding untreated soil, suggesting a negative effect of Granstar® herbicide on Actinobacteria community. Even so, the number of strains isolated from untreated and treated forest soil was quite similar. Among the isolates, resistant strains, tolerating high doses of Granstar® ranging from 0.3 to 0.6% (v/v), were obtained. The two most resistant strains (SRK12 and SRK17) were isolated from treated soils showing the importance of prior exposure to herbicides for bacterial adaptation. SRK12 and SRK17 strains showed different morphological features. The phylogenetic analysis, based on 16S rRNA gene sequencing, clustered the SRK12 strain with four Streptomyces type strains (S. vinaceusdrappus, S. mutabilis, S. ghanaensis and S. enissocaesilis), while SRK17 strain was closely related to Streptomyces africanus. Both strains were unable to grow on tribenuron methyl as unique source of carbon, despite its advanced dissipation. On the other hand, when glucose was added to tribenuron methyl, the bacterial development was evident with even an improvement of the tribenuron methyl degradation. In all cases, as tribenuron methyl disappeared, two compounds were detected with increased concentrations. These by-products appeared to be persistent and were not degraded either chemically or by the studied strains. Based on these observations, we suggested that bacterial activity on carbon substrates could be directly involved in the partial breakdown of tribenuron methyl, by generating the required acidity for the first step of the hydrolysis. Such a process would be interesting to consider in bioremediation of neutral and alkaline tribenuron methyl-polluted soils.

Identification of bifidobacteria isolated from Asian elephant (Elephas maximus).

Bifidobacteria are considered as one of the key genera in intestinal tracts of animals, and their species composition vary depending on the host. The aim of this study was to identify faecal bifidobacteria from Asian elephants (Elephas maximus), housed in Zoological gardens (Ostrava, Czech Republic). Using culturing, bifidobacteria were found in counts 7.60±0.56 log CFU/g. Twenty-six pure strains were isolated from faeces of Asian elephant. The isolates were clustered into two groups according to fingerprinting profiles and fermentation characteristic. Bacteria were identified by a combination of MALDI-TOF MS, PCR methods and sequencing as B. boum (12 isolates) and B. adolescentis (14 isolates). Elephant strains showed different fingerprinting profiles than type and collection strains. Since these two species are frequently isolated from gastrointestinal tract of herbivores, they seem to be typical of animals fed plant diets.

Diversity of Bacterial Community in Fermentation of African Oil Bean Seeds (Pentaciethra macrophylla Benth) by comparison of 16S rRNA Gene Fragments.

Aims: The microbial diversity, fermentation dynamic and the predominant microorganisms involved in the fermentation of African oil bean (Pentaciethra macrophylla Benth) seeds to “Ugba” traditional African food in Eastern Nigeria were investigated by analyzing the microbial community DNA of the food using sequences of their 16S rRNA genes fragment analysis. Study Design: Universal bacterial conserved 16S rRNA gene region was used to study bacterial dynamics as well as the diversity during fermentation stages. Predominant microorganisms were investigated with the view to establishing the best possible starter culture for the production of high flavoured “Ugba”. Place and Duration of Study: Biotechnology Centre of Federal University of Agriculture, Abeokuta, Ogun State, Nigeria, between January 2007 and May 2009. Methodology: Raw seeds were boiled for two hours for easy removal of the seed coats. Peeled seed cotyledons were sliced, cooked for 4hrs until softened. Sliced cotyledons were washed, wrapped in local leafs for fermentation for a period of 96hrs. Sampling for analysis was performed, at every 24 hours interval. Bacterial Community of freshly fermenting “Ugba” was obtained by washing seeds at room temperature in 0.40% NaCl salt solution for 15 minutes. The supernatant was used for streaking on both Nutrient agar and “Ugba” agar plates and for Community DNA extraction. DNA extraction was carried out from community DNA extracts and culture isolates grown in LB (Luria – Bertani) broth at 37°C for 24 hours using Promega DNA extraction kit. Partial 16S rRNA genes of isolates DNA and entire microbial community DNA were amplified using 16S rRNA primers. Amplified fragments were cloned using the PCRTRAP. The transformed clones were sequenced and aligned with reference sequences in the NCBI data base for identification. Results: This analysis indicated that from community DNA, seventeen clones were identified as Bacillus subtilis, Nine as Bacillus pumilus, four as Bacillus licheniformis, two as Bacillaceae bacterium, two as Bacillus sp Van 22, and two as Staphylococcus spp. Also, of the ten sequenced cloned isolates from the cultural technique, eight were identified as Bacillus subtilis, while two sequences were identified as Bacillus pumilus. The percentage abundance revealed that Bacillus subtilis had the highest abundance of 47.2% followed by Bacillus pumilus with 25%. Conclusion: Bacillus subtilis is the predominant species in Ugba fermentation as it had high percentage abundance throughout the fermentation period. This study indicated that molecular analysis of community DNA provides a more accurate picture of diversity and dynamics of microbial communities.

Detection of Clostridium sp. and its Relation to Different Ages and Gastrointestinal Segments as Measured by Molecular Analysis of 16S rRNA Genes

The objective of this study was to establish a specific, sensitive and rapid PCR approach for the detection of Clostridium sp. at the genus level. Clostridium sp. in the duodenum, jejunum, ileum and cecum of broiler chickens were analyzed by 16S rRNA genes. The PCR detected the presence of Clostridium spp. in naturally contaminated intestinal samples. For the total gastrointestinal segments, 53.125, 65.625 and 59.375 percent samples were positive for naturally occurring Clostridium spp. at the ages 4, 14 and 30d, respectively. Analysis of the microbial contents indicated that Clostridium sp. was not consistently detected in all intestinal segments. These results can put in evidence the hypothesis that Clostridium spp. may be interfering in health and performance of chickens.

Clostridium spp. são organismos patogénicos com distribuição mundial, podendo estar presente nos seres humanos, em animais domésticos e em animais selvagens. Estas bactérias habitam geralmente o trato gastrintestinal. Os métodos bacteriológicos convencionais como a microscopia e a cultura têm limitações. O objetivo deste estudo foi de estabelecer uma metodologia específica, sensível e rápida como a ténica de PCR para a deteção de Clostridium spp. A presença de Clostridium spp. Foi pesquisada no duodeno, o jejunum, o íleo e o cecum de galinhas usando análise molecular de genes do rRNA 16S. A técnica de PCR usada neste trabalho detectou Clostridium spp. em amostras intestinais naturalmente contaminadas. Considerando o trato gastrintestinal total, 53.125, 65.625 e 59.375 por cento das amostras foram positivas para Clostridium nas idades 4, 14 e 30d respectivamente. A análise microbiana indicou que Clostridium spp. não foi detectado consistentemente em todos os segmentos intestinais. Os dados observados alertam para possíveis implicações significativas para a saúde e o desempenho das galinhas.