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PubMed2006

Long-term, low-maintenance storage of Acanthamoeba strains.

A simple, low cost method is described for the long-term storage of the potential human pathogen Acanthamoeba. Amoebae are placed in dried, sterile clay pellets within which they form cysts that remain viable and pure for at least 5 years. This method compares favorably with other storage methods and requires no specialist equipment. We have demonstrated that amoeba stored by this method retain both their pathogenic potential and their small subunit ribosomal DNA sequence type.

Acanthamoeba↗
PubMed2006

X-linked creatine transporter (SLC6A8) mutations in about 1% of males with mental retardation of unknown etiology.

Mutations in the creatine transporter gene, SLC6A8 (MIM 30036), located in Xq28, have been found in families with X-linked mental retardation (XLMR) as well as in males with idiopathic mental retardation (MR). In order to estimate the frequency of such mutations in the MR population, a screening of 478 males with MR of unknown cause was undertaken. All 13 exons of SLC6A8 were sequenced using genomic DNA. Six novel potentially pathogenic mutations were identified that were not encountered in at least 588 male control chromosomes: two deletions (p.Asn336del, p.Ile347del) and a splice site alteration (c.1016+2C>T) are considered pathogenic based on the nature of the variant. A mutation (p.Arg391Trp) should be considered pathogenic owing to its localization in a highly conserved region. Two other missense variants (p.Lys4Arg, p.Gly26Arg) are not conserved but were not observed in over 300 male control chromosomes. Their pathogenicity is uncertain. A missense variant (p.Val182Met), was classified as a polymorphism based on a normal creatine/creatinine (Cr:Crn) ratio and cerebral creatine signal in proton magnetic resonance spectroscopy (H-MRS) in the patient. Furthermore, we found 14 novel intronic and neutral variants that were not encountered in at least 280 male control chromosomes and should be considered as unclassified variants. Our findings of a minimum of four pathogenic mutations and two potentially pathogenic mutations indicate that about 1% of males with MR of unknown etiology might have a SLC6A8 mutation. Thus, DNA sequence analysis and/or a Cr:Crn urine screen is warranted in any male with MR of unknown cause.

Amino Acid Sequence↗
PubMed1981

Bacterial contamination of the cervix and premature rupture of membranes.

The endocervical flora was examined in 32 women with premature rupture of membranes (PROM). Sixty-six pregnant women served as controls. Ten patients with PROM who later developed chorioamnionitis were also included in the study. Samples for culturing were obtained from the endocervix on admission and at delivery and later from the fetal surface of the placenta. Blood for culturing was also taken in cases of chorioamnionitis. The total number of bacteria in the endocervix and placenta was higher in patients with PROM. Anaerobes were the most common, except for the fetal surface of the placenta, where aerobes were found in greater numbers. Cultures of blood from women with chorioamnionitis were positive in seven cases. These findings suggest that the high incidence of pathogenic or potentially pathogenic cervical bacteria in pregnancy is related to chorioamnionitis and PROM.

Amniotic Fluid↗
PubMedDate not supplied

Bacterial pathogens isolated from cockroaches trapped from paediatric wards in peninsular Malaysia.

A survey was conducted in 4 paediatric wards in Malaysia to determine the distribution of various species of cockroaches and to examine their gut contents for bacteria. Cockroaches were trapped from food dispensing areas (kitchens), store rooms, cupboards and open wards. 104 cockroaches were caught, consisting of Periplaneta americana (67.3%), Blattella germanica (26%), P. brunnea (4.8%), and Supella longipalpa (1.9%). Bacteria were isolated from all cockroaches except 3 P. americana. Many bacterial species were identified, including the pathogenic and potentially pathogenic species Shigella boydii, S. dysenteriae, Salmonella typhimurium, Klebseilla oxytoca, K. ozaena and Serratia marcescens.

Animals↗
PubMed2005

Contamination of patients' files in intensive care units: an indication of strict handwashing after entering case notes.

BACKGROUND: The extent to which bedside patients' files become contaminated and the range of bacterial flora attributable to contamination in high-risk areas of the hospital are not known with certainty. The aim of the present study was to determine the degree of contamination of the patient's files and also to analyze and compare the spectrum of contaminant bacterial flora between the intensive care unit (ICU) and surgical wards, the 2 most high-risk areas for nosocomial transmission of infection. METHODS: Microbiologic samples were collected from the exposed outer surface of the patients' files kept bedside in the ICU and surgical wards with sterile swabs moistened with sterile normal saline. Swabs were cultured within an hour of collection on blood agar and MacConkey's agar plates, which were incubated at 37 degrees C for 48 hours. Gram-negative bacilli were identified by Gram's stain, catalase, oxidase tests, and API 20E and API 20NE. Staphylococcus species were identified by Gram's stain, catalase test, and tube coagulase test. Antibiotic susceptibility of the isolated bacteria was determined by the disk diffusion technique according to the criteria of National Committee for Clinical Laboratory Standards (NCCLS). RESULTS: In ICU, 85.2% (87/102) and, in surgical wards, 24.7% (22/89) of patient's files were found to be contaminated with pathogenic and potentially pathogenic bacteria (OR, 17.664; 95% CI: 8.050-39.423; P < .0001). Pseudomonas aeruginosa was the most commonly isolated bacteria (32.3%, 33/102) in ICUs, whereas Staphylococcus aureus was the peak contaminant (11.2%, 10/89) of the files in surgical wards. Methicillin-resistant Staphylococcus aureus (MRSA) was isolated from 6.8% (7/102) of ICU patient's files, whereas only 1.1% (1/89) of patient's files in surgical wards were contaminated with MRSA (OR, 6.484; 95% CI: 3.215-13.463; P < .0001). The multidrug-resistant P aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Serretia marcesens isolated from the patient's files had the same antibiotic resistance pattern as of these bacteria isolated from the patients. CONCLUSION: The majority of the patient's files in ICUs were contaminated often with multidrug-resistant bacteria and even MRSA. Contaminated files could be a source of transmission of infection. To prevent this, handwashing practice should be strictly followed after attending the patient and before entering the case notes in the patient's file. The maintenance of good hand hygiene by the health care workers (HCWs) after handling contaminated files should perhaps be the most prudent approach to prevent patient-patient transmission of infection in high-risk areas including ICU and surgical wards.

Cross Infection↗
PubMed2006

Colonization of dental plaque by respiratory pathogens in dependent elderly.

Pneumonia can be a life-threatening infection, especially in the elderly, and it is a significant cause of morbidity and mortality. The purpose of this study was to assess the existence of oral infectious pathogens potentially causing the respiratory disease in the dependent elderly. The dental plaques of 138 dependent elderly were examined to identify microorganisms by the culture method. Twenty-one species of microorganisms were detected in the dental plaques in this study. In 89 cases out of 138 (64.5%), potential respiratory pathogens colonized in the dental plaques of the dependent elderly. The results of the present study revealed that bacteria that commonly cause respiratory infection colonized in dental plaques of the aged, dependent subjects. Therefore, dental plaques must be considered a specific reservoir of colonization and subsequent aspiration pneumonia in dependent elderly.

Aged↗
PubMed2004

Establishment of HPC(R2A) for regrowth control in non-chlorinated distribution systems.

Drinking water distributed without disinfection and without regrowth problems for many years may show bacterial regrowth when the residence time and/or temperature in the distribution system increases or when substrate and/or bacterial concentration in the treated water increases. An example of a regrowth event in a major German city is discussed. Regrowth of HPC bacteria occurred unexpectedly at the end of a very hot summer. No pathogenic or potentially pathogenic bacteria were identified. Increased residence times in the distribution system and temperatures up to 25 degrees C were identified as most probable causes and the regrowth event was successfully overcome by changing flow regimes and decreasing residence times. Standard plate counts of HPC bacteria using the spread plate technique on nutrient rich agar according to German Drinking Water Regulations (GDWR) had proven to be a very good indicator of hygienically safe drinking water and to demonstrate the effectiveness of water treatment. However, the method proved insensitive for early regrowth detection. Regrowth experiments in the lab and sampling of the distribution system during two summers showed that spread plate counts on nutrient-poor R2A agar after 7-day incubation yielded 100 to 200 times higher counts. Counts on R2A after 3-day incubation were three times less than after 7 days. As the precision of plate count methods is very poor for counts less than 10 cfu/plate, a method yielding higher counts is better suited to detect upcoming regrowth than a method yielding low counts. It is shown that for the identification of regrowth events HPC(R2A) gives a further margin of about 2 weeks for reaction before HPC(GDWR).

Bacteria↗
PubMed2005

Microbiological investigations for sanitary assessment of wastewater treated in constructed wetlands.

Microbiological investigations into the occurrence and fate of pathogens in wastewater were carried out in a multi-annual measurement programme, using samples from three artificial wetlands equipped with pre-treatment systems (multi-chamber septic tanks, lagoons) and predominantly treating domestic wastewater. In this study, the concentrations of indicator organisms and pathogenic or potentially pathogenic microorganisms were determined in the various components or stages of the systems. The evaluation of data from some 3.600 microbiological analyses and a comparison with older data from a plant which has already been operation for 18 y made it possible for the first time ever to include operational factors in the assessment. Average removal of all major indicator organisms and pathogens is 1.5-2.5 log units for one-stage systems and increases to 3-5 log units for multi-stage systems. Significant differences between horizontal and vertical filters were not found. If no clogging problems arise during their operation, multi-stage systems can meet the requirements of the EU bathing water and irrigation water directives. Influent concentration, wastewater temperature, and hydraulic loading rate were found to be major factors of influence. The performance of constructed wetlands in removing microorganisms is clearly superior to that of conventional biological activated sludge systems.

Animals↗
PubMed2002

Ecology of dermatophytes and other keratinophilic fungi in swimming pools and polluted and unpolluted streams.

The biodiversity and richness of keratinophilic fungal communities including dermatophytes were assessed in three stream sites and three swimming pools in the Nablus district in Palestine, using hair baiting (HBT) and surface dilution plate (SDP) techniques, over 8- and 6-month periods, respectively. The effect of wastewater effluent and selected ecological factors on these fungi in relation to species diversity and population densities were also considered. Fifty keratinophilic fungal species were recovered from the aquatic habitats studied, of which 42 were recovered from stream sites and 22 from swimming pools. Of these fungi 6 were either dermatophytes (Microsporum gypseum, and Trichophyton mentagrophytes) or dermatophyte related species (Chrysosporium merdarium, Ch. tropicum, Ch. keratinophilum and T. terrestre). The most frequently isolated species in the three pools were Acremonium strictum and Cladosporium cladosporioides, using Sabouraud dextrose agar medium (SDA). The most abundant species were Acr. strictum, and Aspergillus flavus. However, only 4 species were isolated using the SDA medium amended with 5-flurocytosine (5-FC). The most frequent and abundant species in the three stream sites using SDA medium were Geotricum candidum, and Penicillium chrysogenum. The most frequent species in the three sites using the 5-FC medium, was Paecilomyces lilacinus. Using HBT, the most abundant and frequent species in the three stream sites were G. candidum, and Pa. lilacinus, on SDA medium, and Pa. lilacinus, and Gliocladium nigrovirens on the 5-FC medium. The 5-FC medium was more suitable for the isolation of dermatophytes and closely related species than the SDA medium; 6 were recovered on 5-FC, whereas only one on the SDA medium. Variation in the levels of keratinophilic fungal populations from the three stream sites sampled 5 times over an 8-month period, followed comparable fluctuation patterns. Wastewater affected fungal population densities with the highest levels in the un-polluted stream sites, and lowest in the heavily polluted sites. Swimming pools, polluted and un-polluted stream sites were found to be rich in pathogenic and potentially pathogenic fungi.

Arthrodermataceae↗
PubMed1989

Trimethoprim-polymyxin B sulphate ophthalmic ointment versus chloramphenicol ophthalmic ointment in the treatment of bacterial conjunctivitis--a review of four clinical studies. The Trimethoprim-Polymyxin B Sulphate Ophthalmic Ointment Study Group.

Five hundred and twenty-eight patients with a clinical diagnosis of bacterial conjunctivitis were enrolled in four randomized, double-blind, parallel studies. Patients were treated with trimethoprim-polymyxin B sulphate (TP) or chloramphenicol ophthalmic ointments, four times a day for seven days in three studies, and three times a day for five days in one. Data suitable for evaluation of efficacy and safety were obtained from 448 patients. The results of each study were analysed separately and indicated that both treatments were effective and well tolerated and that there were no statistically significant differences between them. However, in three studies, efficacy trends generally favoured TP ophthalmic ointment and in one study efficacy trends favoured chloramphenicol ophthalmic ointment. A wide range of pathogenic or potentially pathogenic organisms was isolated, with Haemophilus influenzae being the most prevalent.

Adolescent↗
PubMed1997

Crohn's disease and Escherichia coli. A new approach in therapy to maintain remission of colonic Crohn's disease?

Involvement of pathogenic or potentially pathogenic bacteria in the pathogenesis of inflammatory bowel disease has long been suggested because, among other reasons, the inflammatory response resembles that in infectious bowel diseases. Elevated antibody levels to pathogen antigens and a changed metabolic activity of the intestinal microflora have been detected in patients with Crohn's disease. Several studies have revealed a possible etiologic link between intestinal microorganisms and inflammatory bowel disease. Therefore, several therapeutic strategies, including reduction or dilution of bacterial components in the intestine by antibiotics or intestinal lavage, respectively, inactivation of inflammatory bacterial products, and reconstitution of intestinal microflora have been employed, substantiating the idea that dysfunction of the intestinal mucosal barrier and an alteration of bacterial composition contribute to the inflammatory disease. However, the beneficial effect of restoration of the physiologic intestinal microflora in colonic inflammation by exogenous administration of a viable nonpathogenic bacterium has not been investigated before in a placebo-controlled study. Promising results came from the present pilot study in which the nonpathogenic Escherichia coli strain Nissle 1917 was tested for efficacy and tolerance in maintaining remission in patients with colonic Crohn's disease. Application of the physiologic bacteria reduced the risk for relapse and minimized the need for glucocorticoids. Therefore we are convinced that in Crohn's disease parts of the intestinal microflora, including the host's immune response toward indigenous flora or an impairment of the gut flora's metabolic activity are involved in the development or at least in the onset of relapse from remissive of colonic Crohn's disease. However, more data are necessary to prove the benefit of E. coli strain Nissle 1917 as a new therapy to maintain remission of colonic Crohn's disease.

Biological Therapy↗
PubMed1998

Invasive aspergillosis. Clinical features of 35 proven cases at a single institution.

Thirty-five patients with clinical features and histologically or microbiologically proven infection met predetermined stringent criteria for invasive aspergillosis over a 5-year period at our institution. Underlying conditions included hematologic malignancy, solid tumor, bone marrow and solid organ transplantation, and immunosuppressive therapy. The majority of patients (94%) presented with respiratory symptoms and abnormal pulmonary chest radiography; only 40% had neutropenia at time of infection. Invasive aspergillosis was suspected in only 21 cases (60%). Concomitant infections were present in 83% of patients. Half of patients had pathogenic or potentially pathogenic microorganisms other than Aspergillus spp. isolated from pulmonary specimens at time of aspergillosis. Aspergillus spp. were recovered from sputum in 75% of patients and from bronchoalveolar lavage in only 52%. Invasive aspergillosis is an unexpectedly unrecognized disease with poor outcome; overall mortality was 94% in our series. The lack of sensitivity of diagnostic procedures, together with the high frequency of concomitant infections, delays the time of diagnosis. Early diagnostic tests are needed, and presumptive antifungal therapy among high-risk patients is mandatory.

Adult↗
PubMed2006

Detection of typical and atypical enteropathogenic Escherichia coli (EPEC) in Iranian children with and without diarrhoea.

The present study was performed to investigate the contribution of typical and atypical enteropathogenic Escherichia coli (EPEC) as a cause of infectious diarrhoea among children less than 10 years old in Iran. During the summer months, 247 specimens from children with diarrhoea and 1108 from asymptomatic children were analysed for the presence of EPEC and other bacterial pathogens. Potential enteric pathogens were identified in 140 cases of children with diarrhoea (56.7%). EPEC was the most frequently identified agent (111 cases), followed by Shiga toxin-producing E. coli (13), Shigella (9), Salmonella (6) and Aeromonas sp. (1). EPEC isolates were examined for the presence of eaeA, bfpA and stx genes by PCR. EPEC isolates were classified as typical (eaeA+ bfpA+) or atypical (eaeA+ bfpA-). Typical EPEC was diagnosed in 35 cases (11.8%), compared with 8 (0.4%) in the asymptomatic group (P<0.05). Atypical EPEC strains were isolated from 23 cases (9.3%), compared with 13 (1.2%) of the healthy control group (P<0.05). In conclusion, the data suggest that typical and atypical EPEC are an important cause of diarrhoea in Iranian children.

Adhesins, Bacterial↗
PubMed1995

Comparative virulence of periodontopathogens in a mouse abscess model.

OBJECTIVE(S): This report compares the virulence of selected strains of P. gingivalis, A. actinomycetemcomitans, C. rectus, F. nucleatum and T. denticola in a murine model as a measure of pathogenic potential of these oral microorganisms. The characteristics of the tissue destruction associated with these monoinfections were then related to a potential model for bacterial synergism in progressing periodontitis. DESIGN AND METHODS: All bacterial strains were grown to mid-logarithmic to early stationary growth phase, harvested and used at various doses to challenge BALB/c normal and BALB/c dexamethasone (DEX) treated mice to mimic a neutrophil dysfunction. The characteristics of tissue destruction, and overt tissue destructive capacity of these species were examined as a function of challenge dose and time. OUTCOME MEASURES: The mice were examined for an interval of approximately 15 days post-challenge and the presence/absence of lesions, localized or generalized nature of the lesion (including size in mm2), and lethality of the infection were assessed. RESULTS: Comparison of the virulence of the various P. gingivalis strains related to lethality and lesion size associated with destruction of the connective tissue, indicated a virulence capacity of P. gingivalis strains 53977>W50 = T22>3079>33277>381. C. rectus elicited localized necrotic lesions which were limited to the epithelial layers of the skin. The size of the lesions also indicated a graded difference in virulence, such that C. rectus strains 234>576>>33238. A. actinomycetemcomitans caused the formation of classic localized abscesses with a PMN infiltrate and inflammatory exudates. Although each of the A. actinomycetemcomitans strains exhibited a similar virulence pattern in this murine model, A. actinomycetemcomitans serotype b representative strains were potentially more pathogenic with a virulence capacity of 3113D-N = 3975A>JP2 > or = Y4>29523>33384. Both C. rectus and A. actinomycetemcomitans strains showed clear evidence that recent clinical isolates were more virulent than laboratory strains. Challenge with F. nucleatum resulted in tissue destructive responses which were different from those observed with the other strains used in this study. A rapid onset of dose-dependent lesion development, related to the formation of either closed abscesses or open lesions, was observed with F. nucleatum. Tissue involvement was also greater at lower F. nucleatum doses when compared to the other bacteria. F. nucleatum challenge of DEX-treated mice resulted in a shift to open lesions. T. denticola appeared to be more tissue invasive than the other species examined in this study. Challenge of mice with T. denticola resulted in involvement of multiple tissues, including epithelial and connective tissues, as well as appearing to invade muscle layers and deeper tissues. In addition to invading deeper tissues, the resulting lesions took considerably longer to resolve. In the DEX-treated mice (neutrophil depleted), P. gingivalis, C. rectus, and A. actinomycetemcomitans were significantly more virulent. In contrast, while DEX treatment altered the characteristics of lesions caused by F. nucleatum, the extent of lesions produced by F. nucleatum and T. denticola was not substantially enhanced. CONCLUSIONS: The results obtained from this study suggest that different microorganisms have the ability to provide individual pathologies which may act in an additive/synergistic fashion contributing to the tissue destruction noted in periodontitis.

Abscess↗
PubMed1978

New knowledge in human milk immunoglobulin.

One of the anti-infection principles of maternal milk is the predominant milk immunoglobulin, secretory IgA. This immunoglobulin contains antibodies against many pathogens and potential pathogens, viruses as well as bacteria, including several members of Enterobacteriacae. The antigenic stimuli for these milk antibodies seem to take place in the Peyer's patches of the intestine. Lymphoid cells leaving the patches after antigenic exposure seem to home to the mammary glands via the lymph and blood circulation. As a result, the milk contains secretory IgA antibodies against, among other things, the intestinal bacteria of the mother. These milk antibodies might reflect the spectrum of bacteria and viruses in the community and may be important for the protection of the breast-fed baby. Via the same homing mechanism the maternal milk obtains antibodies against dietary antigens, including cow's milk proteins. Studies of infants on mixed feeding suggest that the secretory IgA antibodies against the bovine proteins diminish the antigenic exposure, indicating the possibility of an anti-allergic mechanism.

Antibody Formation↗
PubMed1977

Single-cell protein as a bacterial substrate.

It was found that the pathogenic and potentially pathogenic bacteria tested were able to grow and produce extracellular enzymes and toxins in substrates based on extract from various products of Single-cell protein (SCP), as well as in suspensions of SCP. In addition to the hygienic aspects of these findings the possibility of utilizing SCP as substrate for cultivation of bacteria is pointed out.

Bacteria↗
PubMed2004

Intraspecific diversity of Yersinia pestis.

Increased interest in the pathogenic potential of Yersinia pestis has emerged because of the potential threats from bioterrorism. Pathogenic potential is based on genetic factors present in a population of microbes, yet most studies evaluating the role of specific genes in virulence have used a limited number of strains. For Y. pestis this issue is complicated by the fact that most strains available for study in the Americas are clonally derived and thus genetically restricted, emanating from a strain of Y. pestis introduced into the United States in 1902 via marine shipping and subsequent spread of this strain throughout North and South America. In countries from the former Soviet Union (FSU), Mongolia, and China there are large areas of enzootic foci of Y. pestis infection containing genetically diverse strains that have been intensely studied by scientists in these countries. However, the results of these investigations are not generally known outside of these countries. Here we describe the variety of methods used in the FSU to classify Y. pestis strains based on genetic and phenotypic variation and show that there is a high level of diversity in these strains not reflected by ones obtained from sylvatic areas and patients in the Americas.

Americas↗
PubMed1994

The medically important aerobic actinomycetes: epidemiology and microbiology.

The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medically important aerobic actinomycetes may cause significant morbidity and mortality, in particular in highly susceptible severely immunocompromised patients, including transplant recipients and patients infected with human immunodeficiency virus. However, the diagnosis of these infections may be difficult, and effective antimicrobial therapy may be complicated by antimicrobial resistance. The taxonomy of these microorganisms has been problematic. In recent revisions of their classification, new pathogenic species have been recognized. The development of additional and more reliable diagnostic tests and of a standardized method for antimicrobial susceptibility testing and the application of molecular techniques for the diagnosis and subtyping of these microorganisms are needed to better diagnose and treat infected patients and to identify effective control measures for these unusual pathogens. We review the epidemiology and microbiology of the major medically important aerobic actinomycetes.

AIDS-Related Opportunistic Infections↗