ABSTRACT
AIMS: To assess the virulence of Aeromonas spp. using two models, a neonatal mouse assay and a mouse intestinal cell culture. METHODS AND RESULTS: After artificial infection with a variety of Aeromonas spp., mRNA extracts from the two models were processed and hydridized to murine microarrays to determine host gene response. Definition of virulence was determined based on host mRNA production in murine neonatal intestinal tissue and mortality of infected animals. Infections of mouse intestinal cell cultures were then performed to determine whether this simpler model system's mRNA responses correlated to neonatal results and therefore be predictive of virulence of Aeromonas spp. Virulent aeromonads up-regulated transcripts in both models including multiple host defense gene products (chemokines, regulation of transcription and apoptosis and cell signalling). Avirulent species exhibited little or no host response in neonates. Mortality results correlated well with both bacterial dose and average fold change of up-regulated transcripts in the neonatal mice. CONCLUSIONS: Cell culture results were less discriminating but showed promise as potentially being able to be predictive of virulence. Jun oncogene up-regulation in murine cell culture is potentially predictive of Aeromonas virulence. SIGNIFICANCE AND IMPACT OF THE STUDY: Having the ability to determine virulence of waterborne pathogens quickly would potentially assist public health officials to rapidly assess exposure risks.
Subject(s)
Aeromonas/pathogenicity , Gram-Negative Bacterial Infections/microbiology , Virulence , Aeromonas/classification , Aeromonas/genetics , Animals , Animals, Newborn , Cells, Cultured , Disease Models, Animal , Gene Expression Profiling/methods , Gene Expression Regulation, Bacterial , Humans , Intestine, Small/microbiology , Mice , Mice, Transgenic , Oligonucleotide Array Sequence Analysis/methods , Up-Regulation , Water MicrobiologyABSTRACT
Nontuberculous mycobacteria (NTM) are a major cause of opportunistic infection in immunocompromised hosts. Because there is no evidence of person-to-person transmission and NTM have been found in drinking water, the environment is considered a likely source of infection. In this study the widespread occurrence of NTM was examined in drinking water, bottled water, and ice samples. A total of 139 samples were examined for NTM by a membrane filtration culture technique followed by PCR amplification and 16S rRNA sequence determination to identify the isolates. NTM were not detected in bottled water or cisterns but were detected in 54% of the ice samples and 35% of the public drinking-water samples from 21 states. The most frequently occurring isolate was M. mucogenicum (formerly referred to as an M. chelonae-like organism).
Subject(s)
Mycobacterium/classification , Mycobacterium/isolation & purification , Nontuberculous Mycobacteria/isolation & purification , Water Microbiology , Water Supply , Colony Count, Microbial , DNA, Bacterial/genetics , DNA, Ribosomal/genetics , Environmental Microbiology , Mycobacterium/genetics , Nontuberculous Mycobacteria/classification , Nontuberculous Mycobacteria/genetics , Polymerase Chain Reaction/methods , RNA, Ribosomal, 16S/geneticsABSTRACT
Arcobacter butzleri was isolated from a contaminated ground water source. These organisms, previously designated as aerotolerant Campylobacter, were capable of surviving in the ground water environment. Specific DNA probes were used to characterize the isolates in the initial identification and survival studies. Arcobacter butzleri was found to be sensitive to chlorine inactivation.
Subject(s)
Gram-Negative Bacteria/isolation & purification , Water Microbiology , Campylobacter/classification , Campylobacter/drug effects , Campylobacter/growth & development , Campylobacter/isolation & purification , Chlorine/pharmacology , Colony Count, Microbial , Disinfection , Fresh Water , Gram-Negative Bacteria/classification , Gram-Negative Bacteria/drug effects , Gram-Negative Bacteria/growth & development , Polymerase Chain ReactionABSTRACT
Fifty-four algal species were tested for cross-reaction in the American Society for Testing and Materials Giardia/Cryptosporidium indirect immunofluorescence assay, and 24 showed some degree of fluorescence. Two species, Navicula minima and Synechococcus elongatus, exhibited a bright apple green fluorescence. The addition of goat serum to the assay mixture blocked the fluorescence of most nontarget organisms tested and also decreased the background fluorescence. Goat serum did not interfere with the fluorescence of Giardia cysts or Cryptosporidium oocysts or the identification of cyst and oocyst internal structures.
Subject(s)
Cryptosporidium parvum/isolation & purification , Eukaryota/isolation & purification , Giardia lamblia/isolation & purification , Animals , Antibodies, Blocking , Cross Reactions , Cryptosporidium parvum/ultrastructure , Culture Media , Cyanobacteria/isolation & purification , Cyanobacteria/ultrastructure , Eukaryota/classification , Eukaryota/ultrastructure , Fluorescent Antibody Technique, Indirect , Giardia lamblia/ultrastructure , Goats , Species Specificity , Water/parasitologyABSTRACT
This paper demonstrates how the polymerase chain reaction can be used to increase the sensitivity of detection of Leishmania parasites by DNA hybridization methods through the amplification of the minicircle target sequence. The oligonucleotide primers used are able to direct the amplification of all Leishmania strains tested. In addition, the PCR products from L. mexicana and L. braziliensis strains can be distinguished by hybridization with kDNA probes. The method is sensitive enough to detect the kDNA from a single organism and this sensitivity allows the use of nonradioactive hybridization methods. This method can be used to detect Leishmania from human biopsy material.
