Bacteria In Areas Research Articles

Taxonomic Diversity and Functional Traits of Soil Bacterial Communities under Radioactive Contamination: A Review.

Studies investigating the taxonomic diversity and structure of soil bacteria in areas with enhanced radioactive backgrounds have been ongoing for three decades. An analysis of data published from 1996 to 2024 reveals changes in the taxonomic structure of radioactively contaminated soils compared to the reference, showing that these changes are not exclusively dependent on contamination rates or pollutant compositions. High levels of radioactive exposure from external irradiation and a high radionuclide content lead to a decrease in the alpha diversity of soil bacterial communities, both in laboratory settings and environmental conditions. The effects of low or moderate exposure are not consistently pronounced or unidirectional. Functional differences among taxonomic groups that dominate in contaminated soil indicate a variety of adaptation strategies. Bacteria identified as multiple-stress tolerant; exhibiting tolerance to metals and antibiotics; producing antioxidant enzymes, low-molecular antioxidants, and radioprotectors; participating in redox reactions; and possessing thermophilic characteristics play a significant role. Changes in the taxonomic and functional structure, resulting from increased soil radionuclide content, are influenced by the combined effects of ionizing radiation, the chemical toxicity of radionuclides and co-contaminants, as well as the physical and chemical properties of the soil and the initial bacterial community composition. Currently, the quantification of the differential contributions of these factors based on the existing published studies presents a challenge.

Contamination of a Water Stream and Water Drainage Reaching Matosinhos Beach by Antibiotic-Resistant Bacteria.

Antibiotic-resistant bacteria represent a major public health concern, especially impacting medical care centers and hospitals, thereby challenging the effectiveness of current infection treatment protocols. The emergence and persistence of antimicrobial resistance in the environment have been thoroughly researched, with a focus on the aquatic environment as a potential reservoir of these bacteria in areas with anthropogenic contamination. Having this in mind, this work aims to investigate the water streams of Riguinha and Brito Capelo Street, both of which ultimately flow into Matosinhos Beach in Portugal, to determine the potential presence of fecal contamination. Six water samples were collected and analyzed within twenty-four hours from these two water streams. A phenotypic characterization was performed in various volumes on MacConkey agar with antibiotics. Randomly selected lactose-fermenting gram-negative bacteria underwent antimicrobial susceptibility tests using the agar diffusion method following EUCAST guidelines, covering β-lactam and non-β-lactam antibiotics. The isolates were analyzed through Polymerase Chain Reaction. The findings of this study confirm that both water streams were contaminated by multidrug-resistant bacteria such as Enterobacteriaceae, including Escherichia coli, the KESC group, and Pseudomonas, exhibiting extended-spectrum β-lactamases (ESBL), AmpC β-lactamases, and carbapenemases. These indicate the presence of fecal contamination with relevant antimicrobial-resistant threats.

High resolution 16S rRNA gene Next Generation Sequencing study of brain areas associated with Alzheimer's and Parkinson's disease.

Alzheimer's (AD) and Parkinson's disease (PD) are neurodegenerative conditions characterized by incremental deposition of β-amyloid (Aβ) and α-synuclein in AD and PD brain, respectively, in relatively conserved patterns. Both are associated with neuroinflammation, with a proposed microbial component for disease initiation and/or progression. Notably, Aβ and α-synuclein have been shown to possess antimicrobial properties. There is evidence for bacterial presence within the brain, including the oral pathobiont Porphyromonas gingivalis, with cognitive impairment and brain pathology being linked to periodontal (gum) disease and gut dysbiosis. Here, we use high resolution 16S rRNA PCR-based Next Generation Sequencing (16SNGS) to characterize bacterial composition in brain areas associated with the early, intermediate and late-stage of the diseases. This study reveals the widespread presence of bacteria in areas of the brain associated with AD and PD pathology, with distinctly different bacterial profiles in blood and brain. Brain area profiles were overall somewhat similar, predominantly oral, with some bacteria subgingival and oronasal in origin, and relatively comparable profiles in AD and PD brain. However, brain areas associated with early disease development, such as the locus coeruleus, were substantially different in bacterial DNA content compared to areas affected later in disease etiology.

Molecular Epidemiology of Antimicrobial Resistance and Virulence Profiles of Escherichia coli, Salmonella spp., and Vibrio spp. Isolated from Coastal Seawater for Aquaculture.

The occurrence of waterborne antimicrobial-resistant (AMR) bacteria in areas of high-density oyster cultivation is an ongoing environmental and public health threat given the popularity of shellfish consumption, water-related human recreation throughout coastal Thailand, and the geographical expansion of Thailand's shellfish industry. This study characterized the association of phenotypic and genotypic AMR, including extended-spectrum β-lactamase (ESBL) production, and virulence genes isolated from waterborne Escherichia coli (E. coli) (n = 84), Salmonella enterica (S. enterica) subsp. enterica (n = 12), Vibrio parahaemolyticus (V. parahaemolyticus) (n = 249), and Vibrio cholerae (V. cholerae) (n = 39) from Thailand's coastal aquaculture regions. All Salmonella (100.0%) and half of V. cholerae (51.3%) isolates harbored their unique virulence gene, invA and ompW, respectively. The majority of isolates of V. parahaemolyticus and E. coli, ~25% of S. enterica subsp. enterica, and ~12% of V. cholerae, exhibited phenotypic AMR to multiple antimicrobials, with 8.9% of all coastal water isolates exhibiting multidrug resistance (MDR). Taken together, we recommend that coastal water quality surveillance programs include monitoring for bacterial AMR for food safety and recreational water exposure to water for Thailand's coastal water resources.

Environmental impact and diversity of protease-producing bacteria in areas of leather tannery effluents of Sialkot, Pakistan.

Massive discharge of wastes produced by the processing of leather so far confers the most important environmental challenge facing the tanneries worldwide. Waste material from tanneries mostly consists of skin remnants and proteinaceous substances as by-products of leather processing. In these conditions, protease-producing bacteria play a vital role in degrading wastes in this sludge. Therefore, an investigation was made to study the effect of long-term tannery sludge contamination on the diversity of both protease-producing microbes and of bacterial extracellular proteases near tanneries of Sambrial and Sialkot. The high amount of carbon and nitrogen in the soil samples reflected their effect on the diversity of the microbial communities in these areas. Phylogenetic analysis based on 16S rRNA gene sequences suggest that the isolated proteolytic bacteria belonged to 9 different genera including Pseudomonas (26.19%), Proteus (19.04%), Serratia (16.66%), Klebsiella (14.28%), Providencia (9.52%), Achromobacter (7.14%), Enterobacter (2.38%), Myroides (2.38%), and Acinetobacter (2.38%). Enzyme activity showed that among all Pseudomonas and Proteus showed relatively high protease production, and inhibition studies revealed that proteases produced by all isolates were strongly inhibited by serine and/or metalloprotease inhibitors, and a smaller proportion was inhibited by inhibitors of cysteine and/or aspartic proteases. Furthermore, isolated bacteria revealed promising degradation activities against casein and/or gelatin with only a few that could hydrolyze elastin, suggesting proteases produced by these isolated bacteria belong to different classes of proteases, i.e., serine and metalloproteases. This study provided new insights on the community structure of cultivable protease-producing bacteria near tannery sludge of Sambrial and Sialkot. This study would be beneficial not only for establishing the way for effective degradation of tannery slugs but also for questing the novel properties of proteases for a future technological application.

Indicadores microbiológicos de qualidade do solo em recuperação de um sistema agroflorestal

A verificação da qualidade do solo é um instrumento importante para monitorar a sua degradação, e planejar a implantação de práticas sustentáveis de manejo. Este estudo teve como objetivo avaliar a qualidade do solo em três áreas com sistema agroflorestal localizadas na Associação de Pais e Amigos dos Excepcionais (APAE RURAL) de Campo Mourão, Paraná. As três áreas apresentam estágios distintos: uma inicial, com características de atividade de degradação do solo (Área 1); uma intermediária, onde foi implantado o sistema agroflorestal há um ano (Área 2); e uma avançada, apresentando formação florestal mais madura e perene (Área 3). Foram utilizados três grupos funcionais de microrganismos em cada uma das áreas, sendo eles: fungos totais, bactérias aeróbias e bactérias produtoras de celulase. Todos os microrganismos foram quantificados por Unidades Formadoras de Colônia por grama (UFC/g) de solo diluído. A Área 1 exibiu menor abundância de microrganismos totais, na ordem de 105 UFC; Área 2 apresentou composição intermediária de fungos totais, bactérias aeróbias e bactérias produtoras de celulase, com UFC em torno de 107 para os três grupos funcionais; Área 3 apresentou maior quantidade dos microrganismos em estudo, com maior quantidade de fungos (108), bactérias aeróbias (1010) e bactérias produtoras de celulase (1011). Quando comparadas as áreas dentro de cada grupo funcional, destacou-se a menor quantidade de bactérias aeróbias na Área 1 (107), assim como maior quantidade de bactérias produtoras de celulase na Área 3 (1011). Esses resultados mostram que as áreas têm qualidades distintas em relação a micro-organismos. A Área 1 com menos micro-organismos, a Área 2 com quantidades intermediárias e a Área 3 com mais colônias formadas conforme o esperado devido ao tempo de implantação do sistema agroflorestal em cada área.

Identifying microbially influenced corrosion on surfaces contacted by mill waters

This introduction to microbiologically influenced corrosion (MIC) describes how bacteria can cause MIC where inadequate disinfection of mill water or white water allows biofilms to grow on metal surfaces. Although planktonic bacteria (that float in solution) rarely cause corrosion, sessile bacteria (that adhere to surfaces) can produce corrosive chemicals or promote under-deposit corrosion. The diagnosis of MIC requires knowledge not only of corrosion processes, but also of microbiology, water treatment, and plant operations. Although the presence of bacteria does not prove that the corrosion was caused by MIC, factors such as the presence in the corroded area of bacteria that can cause MIC, of chemical indicators of MIC, of features of the corrosion damage that are characteristic of MIC, and recent operational changes that could have enhanced the activity of microorganisms can combine to provide compelling evidence. Because of the complexity of mill water environments, test data must be reviewed with care because of the possibility that other components of the water could have interfered with the analytical results.

The microbiome and disease: reviewing the links between the oral microbiome, aging, and Alzheimer's disease.

This review, gathered from diverse sources, shows how our microbiome influences health and ultimately how well we age. Evidence linking oral bacteria to Alzheimer's disease (AD) is discussed in the context of aging, drawing together data from epidemiological, experimental, genetic, and environmental studies. Immunosenescence results in increased bacterial load as cell-mediated and humoral immune responses wane. The innate immune system gradually takes over; contributing to the rise in circulating proinflammatory cytokines such as TNFα. Maintaining the integrity of the blood-brain barrier (BBB) against a backdrop of increasing bacterial load is important. Aging may favor the proliferation of anaerobes in the mouth eliciting a robust TNFα response from the oral epithelium. Prolonged exposure to high levels of circulating TNFα compromises the integrity of the BBB. Sensitive techniques now detect the "asymptomatic" presence of bacteria in areas previously thought to be sterile, providing new insights into the wider distribution of components of the microbiome. These "immune-tolerated" bacteria may slowly multiply elsewhere until they elicit a chronic inflammatory response; some are now considered causal in instances of atherosclerosis and back pain. Inflammatory processes have long been associated with AD. We propose for a subset of AD patients, aging favors the overgrowth of oral anaerobes established earlier in life provoking a pro-inflammatory innate response that weakens the BBB allowing bacteria to spread and quietly influence the pathogenesis of AD. Finally, we suggest that human polymorphisms considered alongside components of the microbiome may provide new avenues of research for the prevention and treatment of disease.

BIO_PORE, a mathematical model to simulate biofilm growth and water quality improvement in porous media: Application and calibration for constructed wetlands

Reactive-transport models have been widely used to describe biogeochemical processes in subsurface environments. Horizontal subsurface-flow constructed wetlands fall in that category, and have experienced an exponential widespreading as an alternative wastewater treatment technique in recent years. As a result, the interest in modelling the processes occurring within these systems has proportionally increased. However, the functioning of wetlands is still poorly understood and the applicability of the available models is still limited. BIO_PORE model was built using COMSOL Multiphysics™ platform to help accelerating the development of constructed wetland models and to shed light on their internal functioning. The biokinetic equations of Constructed Wetlands Model number 1 describe bacteria-induced degradation and transformation processes of organic matter, nitrogen and sulphur. Small changes of such equations were required in order to include attachment and detachment of influent particulate components. Nutrients uptake and oxygen release by plant roots were also simulated. Thanks to the new biofilm sub-model, which prevents unlimited growth of bacteria in areas with high substrate concentrations, BIO_PORE model is able to reproduce the dynamic behaviour of constructed wetlands over long-term scenarios. During calibration, the model was fed with previously measured influent pollutant concentrations, water temperatures and flow rates of the first year of operation of a pilot wetland and simulated effluent concentrations of COD and NH4N showed good agreement with experimental data. Water temperatures had a great impact on the model output, whereas the inclusion of plants did not cause noticeable differences.

The variability of soil microbial community composition of different types of tidal wetland in Chongming Dongtan and its effect on soil microbial respiration

Previous studies have shown that the soil enzyme activity and microbial respiration intensities varied in two different types of tidal wetland in Chongming Dongtan, the first a sandy soil in a scouring bank with Phragmites australis and the second a saline-alkali clay soil in silting bank with P. australis/ Spartina alterniflora/ Scirpus mariqueter, resulting in different organic carbon reservation capabilities; however, their microbial biomass did not differ significantly. To clarify the microbial mechanism that explains the variability of soil respiration among different wetland areas, the community structure and abundance of soil microorganisms in different types of wetland were investigated using denaturing gradient gel electrophoresis (DGGE) plus real-time quantitative polymerase chain reaction (PCR) technologies, and the relationship between soil environmental factors and the microbial community structure and the soil respiration intensity was elucidated. The results revealed that the soil microbial diversity and community structure differed between the two typical wetland areas. The common population was uncultured bacterium in both areas, and the most abundant community was α-, β-, γ- Proteobacteria, which play an important role in the cycling of carbon in soil. However, the abundance of α- Proteobacteria in Area A was 18.2% of that in Area B ( P <0.05), while the β- Proteobacteria in Area A was 3.23 times higher than that in Area B ( P <0.05). In addition, one cellulose-degrading bacteria, uncultured Bacilli, was detected in Area A. PCA (Principal component analysis) revealed that γ- Proteobacteria and β- Proteobacteria had the greatest impact on soil respiration intensity. Both soil water content and salinity depressed the propagation of β- Proteobacteria. Considering the similar microbial biomass and abundance of γ- Proteobacteria between the two areas, the lower level of β- Proteobacteria, uncultured Bacilli bacterium in Area B might be important factors involved in the lower soil respiration, and hence the higher soil organic carbon reservation capability in Area B.

Diel variations in frequency of dividing cells and abundance of aerobic anoxygenic phototrophic bacteria in a coral reef system of the South China Sea

With the ability of photoheterotrophic metabolism, aerobic anoxygenic phototrophic (AAP) bacteria are an important bacterial group in the marine microbial community. We investigated the diel variations of AAP bacteria in the coral reef water of the South China Sea, and report, for the first time, the frequency of dividing cells (FDC) of AAP bacteria. Our results showed that AAP bacte- rial abundance ranged from 1.54 × 10 4 ± 3.21 × 10 2 to 3.59 × 10 4 ± 3.04 × 10 3 cells ml -1 . The diel pat- tern of AAP bacterial abundance had 2 peak values, one at night around 21:00 h and the other in the daytime at around 9:00 h. Tidal current and light were the primary factors controlling the diel varia- tions of AAP bacteria in this area during our study period. FDC values in AAP and total bacteria were both higher during the night than during the day. The FDC values in AAP bacteria (3.53 ± 1.09 to 9.43 ± 0.80%) were significantly higher than those in total bacteria (1.06 ± 0.06 to 3.14 ± 1.38%), indicat- ing higher growth rate of AAP bacteria than total bacteria in the study area.

Unique ecophysiology among U(VI)-reducing bacteria as revealed by evaluation of oxygen metabolism in Anaeromyxobacter dehalogenans strain 2CP-C.

Anaeromyxobacter spp. respire soluble hexavalent uranium, U(VI), leading to the formation of insoluble U(IV), and are present at the uranium-contaminated Oak Ridge Integrated Field Research Challenge (IFC) site. Pilot-scale in situ bioreduction of U(VI) has been accomplished in area 3 of the Oak Ridge IFC site following biostimulation, but the susceptibility of the reduced material to oxidants (i.e., oxygen) compromises long-term U immobilization. Following oxygen intrusion, attached Anaeromyxobacter dehalogenans cells increased approximately 5-fold from 2.2x10(7)+/-8.6x10(6) to 1.0x10(8)+/-2.2x10(7) cells per g of sediment collected from well FW101-2. In the same samples, the numbers of cells of Geobacter lovleyi, a population native to area 3 and also capable of U(VI) reduction, decreased or did not change. A. dehalogenans cells captured via groundwater sampling (i.e., not attached to sediment) were present in much lower numbers (<1.3x10(4)+/-1.1x10(4) cells per liter) than sediment-associated cells, suggesting that A. dehalogenans cells occur predominantly in association with soil particles. Laboratory studies confirmed aerobic growth of A. dehalogenans strain 2CP-C at initial oxygen partial pressures (pO2) at and below 0.18 atm. A negative linear correlation [micro=(-0.09xpO2)+0.051; R2=0.923] was observed between the instantaneous specific growth rate micro and pO2, indicating that this organism should be classified as a microaerophile. Quantification of cells during aerobic growth revealed that the fraction of electrons released in electron donor oxidation and used for biomass production (fs) decreased from 0.52 at a pO2 of 0.02 atm to 0.19 at a pO2 of 0.18 atm. Hence, the apparent fraction of electrons utilized for energy generation (i.e., oxygen reduction) (fe) increased from 0.48 to 0.81 with increasing pO2, suggesting that oxygen is consumed in a nonrespiratory process at a high pO2. The ability to tolerate high oxygen concentrations, perform microaerophilic oxygen respiration, and preferentially associate with soil particles represents an ecophysiology that distinguishes A. dehalogenans from other known U(VI)-reducing bacteria in area 3, and these features may play roles for stabilizing immobilized radionuclides in situ.

Infections of granulocytic ehrlichiae and Borrelia burgdorferi in white-tailed deer in Connecticut.

Serum or whole blood samples, obtained from 141 white-tailed deer (Odocoileus virginianus) in Connecticut (USA) during 1980, 1991, and 1996, were analyzed to detect past or current infections of Ehrlichia phagocytophila genogroup organisms and Borrelia burgdorferi. When the BDS or NCH-1 strains of granulocytic ehrlichiae were used separately in indirect fluorescent antibody (IFA) staining methods, antibody positivity rates varied from 25 to 64% in 1991 and 1996, respectively. All 50 sera tested from 1980 collections were negative. Although percentages of sera with B. burgdorferi antibodies, as detected by an enzyme-linked immunosorbent assay, also differed (23 to 53%), there were coexisting antibodies to both bacteria in 20 (49%) of 41 sera. In tests on specificity, 19 deer sera with ehrlichial antibodies also were tested by IFA staining procedures for Anaplasma marginale antibodies; one serum with a titer of 1:5,120 to ehrlichial antigen reacted to A. marginale antigen at a serum dilution of 1:320. In parallel analyses of 69 sera, results of Western blot analyses for ehrlichial infections in deer were concordant (72% agreement) with those of IFA staining methods containing ehrlichial antigen. All positive immunoblots showed bands to peptides of the NCH-1 strain of the human granulocytic ehrlichiosis (HGE) agent having molecular masses of about 44, 105, or 110 kDa. In polymerase chain reaction (PCR) studies of blood samples from 63 deer, 11 (18%) specimens were positive for 16S ribosomal DNA of an Ehrlichia phagocytophila genogroup organism, whereas 23 (37%) samples were positive for the DNA of the 44 kDa gene of the HGE agent. White-tailed deer are exposed to different tick-borne bacteria in areas where Ixodes scapularis ticks are abundant and may, in some instances, have had concurrent infections.

Evaluation of Hand-Trimming, Various Sanitizing Agents, and Hot Water Spray-Washing as Decontamination Interventions for Beef Brisket Adipose Tissue

Various chemical solutions (5% hydrogen peroxide, 0.5% ozone, 12% trisodium phosphate, 2% acetic acid, and 0.3% commercial sanitizer), water (16 to 74°C) spray-washing interventions, and hand-trimming/spray-washing treatments were compared for their ability to remove fecal material and to reduce bacterial contamination on beef brisket fat samples in a model spray-washing cabinet. The samples were inoculated with 2.5 cm2 of a bovine fecal paste inoculated with Escherichia coli (ATCC 11370). Hand-trimming followed by spray-washing with plain water (16 to 74°C when it came in contact with the sample; 20.68 bar pressure; for 36 or 12 s corresponding to chain speeds of 100 or 300 carcasses per h) lowered (P < 0.05) microbiological counts, compared to the inoculated control, by 1.41 to 2.50 log colony-forming units (CFU)/cm2. Additionally, spraying with chemical solutions (16°C; 1.38 bar, 12 or 36 s), before or after spray-washing with plain water (20.68 bar) of 16°C (36 s), 35°C (12 s) or 74°C (12 s) reduced bacterial counts by 1.34 to 2.87, 1.18 to 2.86, or 0.96 to 3.42 log CFU/cm2, respectively. Reduction in counts was influenced by water temperature (16 to 74°C), type of chemical solution, and sequence of spray application. Under the conditions of this study, hydrogen peroxide and ozonated water were more effective (P < 0.05) than trisodium phosphate, acetic acid, and a commercial sanitizer when applied after first washing with plain water. Trisodium phosphate maintained its activity when used before washing with water. In general, water of 74°C caused reductions (P < 0.05) exceeding 3.0 log CFU/cm2, which were higher than those achieved by trimming and spray-washing. No spreading of bacteria in areas immediately adjacent to the inoculation site was detected following spray-washing.

Serodiagnosis of paratuberculosis in sheep by use of agar gel immunodiffusion

SUMMARY An agar gel immunodiffusion (agid) test was used over a 3-year period to examine 1,871 serum samples from sheep representing 5 Mycobacterium paratuberculosis — infected flocks and 4 flocks presumed to be uninfected. Of 1,032 sheep, 31 had positive agid test results (scoring 1 to 5), and 23 of these 31 were necropsied. Infection with M paratuberculosis was confirmed by 1 or more of the following findings: observation of typical lesions on histologic examination of sections of ileum or ileocecal lymph nodes, observation of clumps of acid-fast bacteria in mucosal smears of ileum, and isolation of the organism from feces or tissue. False-positive results on agid testing were not found in sheep from flocks known to have exposure to Corynebacterium pseudotuberculosis. Diarrhea in infected sheep was observed infrequently; chronic, severe weight loss was the most common sign observed. On histologic examination of tissues from 20 infected sheep, 16 (80%) had diffuse lesions of the ileum and 13 (65%) had acid-fast bacteria in areas of ileal inflammation; 4 had discrete granulomas and peripheral lymphocytic infiltrates in the ileum. Sheep with diffuse lesions tended to have higher mean scores on agid testing and examination for acid-fast bacteria, compared with those from sheep with more discrete lesions. Bacteriologic culture yielded M paratuberculosis from only 3 sheep with paratuberculosis. On the basis of results of this study, we suggest that the nature of the response to infection with M paratuberculosis may influence the results of diagnostic tests for paratuberculosis, and that agid testing may be useful to identify M paratuberculosis infection in sheep with chronic weight loss and in flock-screening programs.

New method for determination of efficacy of health care personnel hand wash products.

A method of studying the effects of health care personnel hand wash products is described. The fingernail regions of the hands of volunteers are inoculated with a mixture of Escherichia coli and Serratia marcescens, and the areas are dried for a standard time. After routine hand washing, each fingernail region is individually scrubbed with an electric toothbrush which moves longitudinally to the handle into collection fluid contained in a petri dish. The test bacteria in the fluid are then enumerated. (Bacillus subtilis spores may be included as tracers to show degree of physical removal of the procedure.) This method has several advantages over the frequently used glove juice technique. Experimental designs with large numbers of volunteers, multiple sampling sites, and many hand wash products may be performed. Ten sampling sites (fingers) are available, versus the two gloved hands for testing products. (Efficiency is almost 100% in the recovery of spore tracers placed on the fingernails.) Many commercial health care personnel hand wash products containing antimicrobial agents substantive to the skin do not rapidly reduce numbers of inoculated bacteria in the fingernail regions to any greater extent than nonantimicrobial hand washes. Products containing isopropanol or ethanol are very effective in decreasing bacteria in areas around and under the fingernails.

Polychlorinated biphenyl (PCB) degrading bacteria and PCB in estuarine and marine environments

Surface water and sediment samples collected throughout the Chesapeake Bay and along the southeast Atlantic Coast, extending from Miami, Florida to Cape Hatteras, North Carolina, were analyzed for the presence of polychlorinated biphenyl (PCB)-degrading bacteria and PCB. PCB-degrading bacteria were recovered from all samples for which enumeration was attempted. In addition, the occurrence of PCB was detected in all samples analyzed for PCB. Both PCB-degrading bacteria and PCB were found in higher concentrations in estuarine waters and sediment, compared with marine samples. The data obtained indicated a greater correlation between PCB concentrations and numbers of PCB degrading bacteria in areas of urbanization as opposed to areas distant from land. These results suggest assessment of existing PCB-degrading bacteria provides a potential indicator of PCB contamination. Because PCB-degrading bacterial populations were much more highly correlated with nutritional factors governing microbial growth, the extent of microbial PCB degradation by natural microbial populations remains undetermined.

LOCALIZATION OF STAPHYLOCOCCI IN AREAS OF INFLAMMATION PRODUCED BY XYLENE

The phrase locus minoris resistentiae is hoary with years, and the initiation of local infective processes by injury unaccompanied with direct infection is a widely recognized fact. 1 Streptococci, when given intravenously, have been observed to localize in abscesses produced by subcutaneous injection of silver nitrate. 2 Benians 3 found that Bacillus typhosus, when injected intravenously in rabbits, localized in areas of skin where agar, mucin and starch had previously been injected. Tubercle bacilli, when present in the blood stream, tend to localize in areas of necrosis and also in tissue showing an increase in vascularity. 4 As early as 1843, Cazenave 5 observed that localization of a secondary syphilitic lesion is commonly determined by some concomitant irritation or morbid condition. Findlay, 6 in 1928, studied the problem of localization of bacteria in areas of injury. He stated: When bacteria are present in the blood stream, their passage through the