Prevalence of Opportunistic Pathogens and Diversity of Microbial Communities in the Water System of a Pulmonary Hospital

Objective Our objective was to investigate the occurrence of opportunistic pathogens and characterize the bacterial community structures in the water system of a pulmonary hospital.Methods The water samples were collected from automatic and manual faucets in the consulting room,treatment room,dressing room,respiratory ward,and other non-medical rooms in three buildings of the hospital.Quantitative polymerase chain reaction was used to quantify the load of several waterborne opportunistic pathogens and related microorganisms,including Legionella spp.,Mycobacterium spp.,and M.avium.Illumina sequencing targeting 16 S r RNA genes was performed to profile bacterial communities.Results The occurrence rates of Legionella spp.,Mycobacterium spp.,and M.avium were 100%,100%,and 76%,respectively in all samples.Higher occurrence rates of M.avium were observed in the outpatient service building(building 1,91.7%)and respiration department and wards(building 2,80%)than in the office building(building 3),where no M.avium was found.M.avium were more abundant in automatic faucets(average 2.21×10~4 gene copies/L)than in manual faucets(average 1.03×10~4 gene copies/m L)(P<0.01).Proteobacteria,Actinobacteria,Bacteroidetes,Cyanobacteria,Firmicutes,and Acidobacteria were the dominant bacterial phyla.Disinfectant residuals,nitrate,and temperature were found to be the key environmental factors driving microbial community structure shifts in water systems.Conclusion This study revealed a high level of colonization of water faucets by opportunistic pathogens and provided insight into the characteristics of microbial communities in a hospital water system and approaches to reduce risks of microbial contamination.

Effects of O3/Cl2 disinfection on corrosion and opportunistic pathogens growth in drinking water distribution systems

The effects of O3/Cl2 disinfection on corrosion and the growth of opportunistic pathogens in drinking water distribution systems were studied using annular reactors （ARs）. The corrosion process and most probable number （MPN） analysis indicated that the higher content of iron-oxidizing bacteria and iron-reducing bacteria in biofilms of the AR treated with O3/Cl2 induced higher Fe304 formation in corrosion scales. These corrosion scales became more stable than the ones that formed in the AR treated with Cl2 alone. O3/Cl2 disinfection inhibited corrosion and iron release efficiently by changing the content of corrosion-related bacteria. Moreover, ozone disinfection inactivated or damaged the opportunistic pathogens due to its strong oxidizing properties. The damaged bacteria resulting from initial ozone treatment were inactivated by the subsequent chlorine disinfection. Compared with the AR treated with Cl2 alone, the opportunistic pathogens M. auium and L. pneumophila were not detectable in effluents of the AR treated with O3/Cl2, and decreased to （4.60 ± 0.14） and （3.09 ± 0.12） loglo （gene copies/g corrosion scales） in biofilms, respectively. The amoeba counts were also lower in the AR treated with O3/Cl2. Therefore, O3/Cl2 disinfection can effectively control opportunistic pathogens in effluents and biofilms of an AR used as a model for a drinking water distribution system.

The control of red water occurrence and opportunistic pathogens risks in drinking water distribution systems:A review

Many problems in drinking water distribution systems(DWDSs)are caused by microbe,such as biofilm formation,biocorrosion and opportunistic pathogens growth.More iron release from corrosion scales may induce red water.Biofilm played great roles on the corrosion.The iron-oxidizing bacteria(IOB)promoted corrosion.However,when iron-reducing bacteria(IRB)and nitrate-reducing bacteria(NRB)became the main bacteria in biofilm,they could induce iron redox cycling in corrosion process.This process enhanced the precipitation of iron oxides and formation of more Fe3 O4 in corrosion scales,which inhibited corrosion effectively.Therefore,the IRB and NRB in the biofilm can reduce iron release and red water occurrence.Moreover,there are many opportunistic pathogens in biofilm of DWDSs.The opportunistic pathogens growth in DWDSs related to the bacterial community changes due to the effects of micropollutants.Micropollutants increased the number of bacteria with antibiotic resistance genes(ARGs).Furthermore,extracellular polymeric substances(EPS)production was increased by the antibiotic resistant bacteria,leading to greater bacterial aggregation and adsorption,increasing the chlorine-resistance capability,which was responsible for the enhancement of the particle-associated opportunistic pathogens in DWDSs.Moreover,O3-biological activated carbon filtration-UV-Cl2 treatment could be used to control the iron release,red water occurrence and opportunistic pathogens growth in DWDSs.

Characterization and Identification of Two Opportunistic Human Bacterial Pathogens in Rice

Burkholderia cepacia （Bc） and Pseudomonas aeruginosa （Pa） are both biocontrol agents in agriculture and opportunistic human pathogens in hospitals. Effective management and utilization practice is needed to understand their characteristics and distribution in rice. During the last decade, the two opportunistic human pathogens were detected in 631 samples of rice seed and 117 samples of rice plant in plain, highland and mountainous rice growing areas of China. Bc and Pa were primarily differentiated by common bacteriological characteristics and pathogenic tests and then identified into species by Biolog and FAME tests. However, the genotypes of Bc still could not be distinguished. It has been noted that the Bc and Pa mainly existed in rice root with the highest distribution frequency in plain areas （ 6.1% and 16.1%） and lowest in the mountainous areas （1.0% and 7.8%）.

Dishwashers provide a selective extreme environment for human-opportunistic yeast-like fungi

Urban life has led to the creation of human-made environments that,from a microbiological perspective,provide extreme life conditions.Certain non-ubiquitous microorganisms such as thermophilic members of the black yeast genus Exophiala are enriched within these habitats for which no counterpart is known in nature.Dishwashers consistently accumulate a number of specific black,white and red yeasts on the rubber seals of doors and in stagnant water at the interior.Several of these yeasts are primarily known as agents of human opportunistic infections.In this review,the literature data are supported by a screening study involving 937 households in 15 cities in Turkey.Fungi were detected in 230 samples(24.5%).Using rDNA sequencing,the prevalent species were identified as Exophiala dermatitidis(n=116),Candida parapsilosis(n=44),E.phaeomuriformis(n=35),Magnusiomyces capitatus(n=22),Rhodotorula mucilaginosa(n=15),and C.lusitaniae(n=14).The possible role of dishwashers in transmitting disease is discussed.

Oral disease is linked to low nestling condition and brood size in a raptor species living in a highly modified environment

Anthropogenic stressors can favor the occurrence of noninfectious disease that can be worsened by the impact of opportunistic pathogens,making the epizootiology of environmental diseases difficult to unravel.The incidence and impact of oral lesions in nestlings of a facultative scavenger species,the black kite Milvus migrans,were examined over seven breeding seasons in the highly degraded environment close to Madrid,Spain.We found an overall prevalence of 31%of nestlings with oral lesions,with no clear spatial pattern in nests with affected and unaffected individuals.The occurrence and number of oral lesions were negatively associated with nestling body condition and brood size.Broods,where all siblings had oral lesions,were smaller than those where some or all siblings were apparently healthy,suggesting that oral disease could be causing nestling mortality and,consequently,brood size reduction.In turn,nestling body condition was negatively affected by lesion occurrence,brood size,and laying date.Although these relationships were bidirectional,piecewise structural equation modeling analyses showed a greater negative effect of body condition on lesion occurrence than vice versa,indicating that nestlings in poorer body condition were more likely to develop oral lesions(which could contribute to aggravate their state of deterioration)than those in better condition.Nestlings from small broods were also more likely to have oral disease(directly or indirectly through their lower body condition)than nestlings from large broods.Nestlings that hatched last in the broods showed greater development stress than those that hatched first.Anthropogenic stressors could trigger poor body condition,and contribute to microbiota dysbiosis-related diseases.Although further research is needed to determine the consequences for the long-term fitness of individuals,actions should be taken to mitigate adverse conditions that may favor the appearance of environmental diseases associatedwithperi-urbanareas,giventheirrapidexpansion overnatural areas.

Revealing the changes of bacterial community from water source to consumers tap:A full-scale investigation in eastern city of China

This study profiled the bacterial community variations of water from four water treatment systems,including coagulation,sedimentation,sand filtration,ozonation-biological activated carbon filtration(O3-BAC),disinfection,and the tap water after the distribution process in eastern China.The results showed that different water treatment processes affected the bacterial community structure in different ways.The traditional treatment processes,including coagulation,sedimentation and sand filtration,reduced the total bacterial count,while they had little effect on the bacterial community structure in the treated water(before disinfection).Compared to the traditional treatment process,O3-BAC reduced the relative abundance of Sphingomonas in the finished water.In addition,ozonation may play a role in reducing the relative abundance of Mycobacterium.NaClO and ClO2 had different effects on the bacterial community in the finished water.The relative abundance of some bacteria(e.g.Flavobacterium,Phreatobacter and Porphyrobacter)increased in the finished water after ClO2 disinfection.The relative abundance of Mycobacterium and Legionella,which have been widely reported as waterborne opportunistic pathogens,increased after NaClO disinfection.In addition,some microorganisms proliferated and grew in the distribution system,which could lead to turbidity increases in the tap water.Compared to those in the finished water,the relative abundance of Sphingomonas,Hyphomicrobium,Phreatobacter,Rheinheimera,Pseudomonas and Acinetobacter increased in the tap water disinfected with NaClO,while the relative abundance of Mycobacterium increased in the tap water disinfected with ClO2.Overall,this study provided the detailed variation in the bacterial community in the drinking water system.

Biliary candidiasis mimicking IgG4-related disease in a patient with normal immunity

Purpose:To report a rare case of biliary candidiasis in a host with normal immunity.Methods:Laboratory tests indicated an elevated G level of 1000 pg/ml.Microscopic examination of pathological sections demonstrated multiple,narrow base,budding yeast cells following Grocott's methenamine silver staining and periodic acid-Schiff staining.Subsequent sequence analysis supported the diagnosis of biliary candidiasis.Results:A 31-year-old previously healthy man developed obstructive jaundice under no obvious inducement.He experienced cholecystectomy and biliary drainage.Surgical specimens revealed granulomatous chronic inflammation in the gallbladder,liver,bile ducts and mesenteric lymph nodes.He was misdiagnosed with tuberculosis and received antituberculosis treatment.However,his condition did not improve.He was finally diagnosed with biliary candidiasis and administered the antifungal treatment with fluconazole.His symptoms improved after such treatment.Conclusions:We reported a case of biliary candidiasis that mimicked IgG4-RD in a host with normal immunity.Our findings highlighted the need for pathological diagnosis in patients with symptoms resembling IgG4-RD.

A multigene phylogeny reveals that Ochroconis belongs to the family Sympoventuriaceae (Venturiales,Dothideomycetes)

Ochroconis is a genus of ascomycete fungi that includes oligotrophic saprobes and some opportunistic species causing infections in vertebrates.The most important of these opportunists is the neurotropic species Ochroconis gallopava,which occurs in birds and occasionally in immunocompromised humans.Other Ochroconis species have been isolated from superficial infections of cats,dogs and fish.In their natural environment,these species are found in litter,soil,and on moist surfaces.Some thermophilic species have been isolated from hot springs,industrial effluents,and self-heated plant material.Although their ecology and epidemiology has been investigated,their classification within the ascomycetes is still unknown.Here,the phylogenetic placement of Ochroconis is investigated using a four-gene phylogeny(nuLSU,nuSSU,mtSSU and RPB2).The results show that Ochroconis and its recently described sister genus Verruconis belong to the order Venturiales(Dothideomycetes)and are nested within the Sympoventuriaceae,a family recently erected for a group of plant-saprobes or-pathogens sister to the Venturiaceae.They form a well-supported monophyletic group together with five species of the anamorphic genus Fusicladium isolated from leaf and needle litters.