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PubMed2006

Is breast milk collected at home suitable for raw consumption by neonates in Brazilian public neonatal intensive care units?

This study was designed to verify if breast milk collected at home is appropriate for raw consumption by neonates in a Brazilian public neonatal intensive care unit (NICU). From May 1998 to February 2000, microbiological characteristics of breast milk samples collected at home were analyzed. The milk samples were considered appropriate for raw consumption if mesophilic bacteria count was < 2500 CFU/mL and potential pathogens were not detected. Of 90 milk samples collected from 32 mothers of hospitalized neonates, 36 (40%) were rejected because of potentially pathogenic bacteria (72.2%), mesophilic bacteria count > or = 2500 CFU/mL (13.9%), and both conditions (13.9%). The most frequent nonpathogenic and potentially pathogenic bacteria isolated were Staphylococcus coagulase negative and Klebsiella pneumoniae, respectively. Using univariate analysis, demographic, socioeconomic, educational, and house characteristics were not found to be associated with milk contamination. Breast milk collected at home may not be appropriate for raw consumption in Brazilian NICUs. Pasteurization could improve its microbiological quality. Further studies are needed.

Adolescent↗
PubMed2026

Spiramycin fermentation residue-derived biochar regulates soil nutrient cycling, microbial communities, and antibiotic resistance gene dynamics.

Spiramycin fermentation residues (SFR) are hazardous wastes enriched with residual antibiotics, yet they can serve as potential feedstocks for resource recovery after appropriate treatment. In this study, SFR-derived biochar (SFR-BC) was produced by pyrolysis and applied to agricultural soil to evaluate its effects on soil properties, microbial communities, potential pathogenic bacteria, antibiotic resistance genes (ARGs), and mobile genetic elements (MGEs). A 60-day soil incubation experiment was conducted with one control and three SFR-BC application rates of 0.5%, 1.0%, and 2.0%. SFR-BC improved soil physicochemical properties, nutrient status, enzyme activities, and microbial alpha diversity. Metagenomic analysis showed that SFR-BC altered the abundance of functional genes associated with carbon and nitrogen cycling, indicating shifts in microbial functional potential. SFR-BC also changed bacterial co-occurrence patterns, with the high-dose treatment showing a more complex and highly connected network structure during incubation. In addition, high-dose SFR-BC reduced several potential pathogenic bacteria, including major plant pathogenic taxa. SFR-BC decreased soil ARG abundance by 9.38%-33.67% and MGE abundance by 6.49%-27.89% relative to the control, showing a dose-dependent reduction in antibiotic resistance-related genetic elements. Network and PLS-PM analyses further indicated that ARG variation was statistically associated with soil physicochemical properties, microbial diversity, potential bacterial hosts, and MGEs. Overall, these results suggest that SFR-BC can improve short-term soil nutrient status and reduce ARGs, MGEs, and several potential pathogenic taxa under controlled incubation conditions, providing useful evidence for the potential valorization of antibiotic fermentation residues through pyrolysis.

Charcoal↗
PubMed2002

Isolation of potential bacterial pathogens from the stool of HIV-infected and HIV-non-infected patients and their antmicrobial susceptibility patterns in Jimma Hospital, south west Ethiopia.

Diarrhea is a major clinical problem in HIV-infected patients. There is a need to monitor antimicrobial susceptibility patterns of enteric bacterial pathogens in order to ensure appropriate treatment and control of infections. The objectives of this study was to identify and determine the magnitude of potential enteric pathogens including Salmonella, Shigella, Campylobacter and other species in HIV-infected and HIV-non-infected patients with diarrhea, to evaluate the current antimicrobial susceptibility pattern of the clinical isolates and the association of enteric bacterial pathogens in HIV infected patients with diarrhea. A cross-sectional study was conducted from Feb-July 2001 on 372 consecutive HIV seropositive and seronegative patients presenting at Jimma hospital for different illnesses. Patients were selected based on their serological tests for HIV. Sample of faeces specimens were collected and inoculated onto standard culture media as well as onto Skirrow's medium for isolation of Campylobacter species. Salmonella and Shigella species were tested for antimicrobial susceptibility using disc agar diffusion technique recommended by Kirby-Bauer. Stool specimens were also smeared and stained by Zehl-Neelson staining technique for the identification of Mycobacterium species. Among the 99 HIV-infected patients with diarrhea, 25 (25.0%) of them had enteric bacteria among which 8(8.1%) were Salmonella, 4(4.0%) Shigella and 13(13.1%) Campylobacter species. Mycobacterium species were identified in 3(3.0%) of stool specimens obtained from HIV-infected patients with diarrhea and another 3 species were detected in HIV-infected patient without diarrhea. Salmonella species were isolated with higher prevalence in HIV-infected than in HIV non-infected patients. These Salmonella isolates were 100% susceptible to Amikacin, Gentamicin, Nalidixic acid and Kanamycin while Shigella isolates were 100% susceptible for Gentamycin and Kanamycin only. Unlike Salmonella, Shigella and Campylobacter species showed higher prevalence rates in HIV non-infected patients. Enteric bacterial pathogens account for about one fourth diarrhea in HIV infected patients in Jimma hospital. The finding of this investigation also confirmed earlier observations of wide spread resistance to the commonly used drugs in this region.

Acute Disease↗
PubMed2002

The potential of pathogens as biological control of parthenium weed (Parthenium hysterophorus L.) in Ethiopia.

P. hsyterophorus is an exotic invasive annual weed now causing severe infestation in Ethiopia. Studies on diagnosis, incidence and distribution of pathogens associated with parthenium weed in Ethiopia were carried out from 1998-2002. Several fungal isolates were obtained from seed and other parts of parthenium plants. Among them were putative pathogenic fungal species of the genus Helminthosporium, Phoma, Curvularia, Chaetomium, Alternaria, and Fusarium. However, pathogenecity test of the isolates obtained showed no or non-specific symptoms. It was concluded that these pathogens could be opportunistic with insignificant potential for biological control of parthenium. Two most important diseases associated with parthenium were a rust disease, caused by Puccinia abrupta var. partheniicola, and a phyllody disease, caused by a phytoplasma of fababean phyllody (PBP) phytoplasma group. The rust was commonly found in cool mid altitude (1500-2500 m) areas while phyllody was observed in low to mid altitude regions (900-2500 m) of Ethiopia, with a disease incidence up to 100% and 75%, respectively, in some locations. Study of the individual effects of the rust and phyllody diseases under field conditions showed a reduction on weed morphological parameters (plant height, leaf area, and dry matter yield). Parthenium seed production was reduced by 42% and 85% due to rust and phyllody, respectively. Phyllody and rust diseases of parthenium showed significant potential for classical biological control of parthenium after further confirmation of insect vectors that transmit phyllody and host range of phyllody disease to the related economic plants in Ethiopia.

Alternaria↗
PubMed2005

A molecular biological protocol to distinguish potentially human pathogenic Stenotrophomonas maltophilia from plant-associated Stenotrophomonas rhizophila.

In recent years, the importance of the Gram-negative bacterium Stenotrophomonas as an opportunistic pathogen as well as in biotechnology has increased. The aim of the present study was to develop new methods for distinguishing between strains closely related to the potentially human pathogenic Stenotrophomonas maltophilia and those closely related to the plant-associated Stenotrophomonas rhizophila. To accomplish this, 58 strains were characterized by 16S rDNA sequencing and amplified ribosomal DNA restriction analysis (ARDRA), and the occurrence of specific functional genes. Based on 16S rDNA sequences, an ARDRA protocol was developed which allowed differentiation between strains of the S. maltophilia and the S. rhizophila group. As it was known that only salt-treated cells of S. rhizophila were able to synthesize the compatible solute glucosylglycerol (GG), the ggpS gene responsible for GG synthesis was used for differentiation between both species and it was confirmed that it only occurred in S. rhizophila strains. As a further genetic marker the smeD gene, which is part of the genes coding for the multidrug efflux pump SmeDEF from S. maltophilia, was used. Based on the results we propose a combination of fingerprinting techniques using the 16S rDNA and the functional genes ggpS and smeD to distinguish both Stenotrophomonas species.

Bacterial Proteins↗
PubMed2001

An examination of risk factors associated with beef cattle shedding pathogens of potential zoonotic concern.

The prevalence of three waterborne zoonotic pathogens (Campylobacter sp., Giardia sp. and Cryptosporidium parvum) in rectal faecal samples from a random sample of adult beef cattle was determined. Management factors that may be associated with shedding of these organisms were examined. For Campylobacter sp. prevalence was 5.0%, and the number of females on the farm was positively associated with the proportion that tested positive. For Giardia sp. prevalence was 6.5%, and none of the management factors examined was significantly associated with the proportion in a herd testing positive. C. parvum was identified in 1.1% of samples. The length of calving season and whether any procedures were performed on the calves in the first 2 days of life were positively associated with the proportion that tested positive. We conclude that this sample of adult beef cattle represent a relatively limited threat to water supplies and subsequent disease transmission to humans from these pathogens.

Animals↗
PubMed1987

Dactylaria constricta: another dematiaceous fungus with neurotropic potential in mammals.

Dacylaria constricta, a neurotropic dematiaceous fungal pathogen of poultry, was evaluated for pathogenic potential in mice. Four isolates of D. constricta and two of Scolecobasidium humicola were injected intravenously into groups of mice. Two isolates of a D. constricta group formerly known as Dactylaria gallopava produced signs of central nervous system infection with cerebral microabscesses and death. None of the mice injected with the two remaining isolates of D. constricta from a group formerly known as Scolecobasidium constrictum or with isolates of S. humicola showed any evidence of infection, and none died. Potential pathogenicity can now be added to the previously established physiological differences to separate isolates of D. constricta into two distinct groups.

Animals↗
PubMed1982

Comparison of six different criteria for judging the acceptability of sputum specimens.

A series of 391 unselected expectorated sputum specimens was examined microscopically, and six different published criteria for judging the acceptability of the specimens were applied. Of the 391 specimens, 234 were found to be acceptable or unacceptable by all six criteria; 157 specimens were discrepant. By the criteria of Murray and Washington and of Barry, 25 and 23% of the specimens, respectively, were rejected; only 19 of 143 specimens which contained potential pathogens as part of their predominant microbial flora were rejected by both sets of criteria. The criteria described by Geckler et al. and Bartlett missed fewer potential pathogens; only 9 or 17% of the specimens, respectively, were found unacceptable. The criteria of Heineman and Radano and of Van Scoy resulted in the greatest percentages of specimens judged unacceptable (28 and 29%, respectively), including 19 and 24% of specimens containing potential pathogens. The reproducibility of sputum screening results was also assessed, comparing the method of Murray and Washington with that of Barry. Six separate slides were prepared from each of 45 different specimens: three samples with purulent or bloody flecks and three samples in which the specimens had been mixed with an applicator swab. Satisfactory reproducibility was observed with both criteria and both sampling methods; no significant differences in reproducibility could be documented in this limited series.

Bacteria↗
PubMed2002

Infection rates in surgical neonates and infants receiving parenteral nutrition: a five-year prospective study.

We performed a prospective, observational, cohort study on 208 surgical neonates and infants between 1992 and 1997. Surveillance cultures of the oropharynx and rectum were obtained at the start of parenteral nutrition and thereafter twice weekly. Blood cultures were taken on clinical indication only. Microbial translocation was diagnosed when the micro-organisms in the blood were not distinguishable from those carried in the oropharynx and/or rectum. Liver function was monitored weekly and when septicaemia was suspected. The incidence of septicaemia was 15%. The predominant micro-organisms (86%) were the low-level pathogens, coagulase-negative staphylococci and enterococci. Potential pathogens, including aerobic Gram-negative bacilli, were responsible for the remainder. Microbial translocation was responsible for 84% of septicaemic episodes in 76% of patients. The potential pathogens caused septicaemia significantly later than coagulase-negative staphylococci, at a time when liver function was significantly more impaired. In neonates and infants receiving parenteral nutrition, septicaemia is mainly a gut-derived phenomenon and requires novel strategies for prevention.

Bacteremia↗
PubMed2006

The intestinal bacterial colonisation in preterm infants: a review of the literature.

The aim of this study is to review the normal development of the intestinal microflora of preterm infants and the factors influencing its development. Preterm infants have an increased intestinal permeability, which may lead to bacterial translocation to systemic organs and tissues. In combination with immaturity of the immune system the risk to systemic infections might be increased. Especially potential pathogenic bacteria are able to translocate. The intestinal microflora of breast-fed term infants, dominated by bifidobacteria and lactobacilli, is thought to suppress the growth of potentially pathogenic bacteria. Many attemps have been made to stimulate the presence of bifidobacteria and lactobacilli with changes in the diet and ingredients-like prebiotics and probiotics. After selection, six studies were included reviewing the intestinal bacterial colonisation of preterm infants. In general, these studies show that the intestinal bacterial colonisation with beneficial bacteria is delayed in preterm infants. The number of potentially pathogenic bacteria is high. Antibiotics influence the intestinal colonisation. Many preterm infants receive prophylactic antibiotics at birth. As antibiotics delay the normal intestinal colonisation, caution should be given to the treatment with broadspectrum antibiotics in preterm infants at birth and every attempt has to be made to restrict the period of treatment.

Anti-Bacterial Agents↗
PubMed1984

The digestive tract in immunocompromised patients: importance of maintaining its resistance to colonization, especially in hospital in-patients and those taking antibiotics.

The colonization resistance (CR) of the gastrointestinal tract to potential pathogens depends partly on factors within the host but to a greater extent on the normal (anaerobic) gut flora. Its strength varies between individuals. These individual differences in resistance to colonization by pathogenic microorganisms may explain differences in susceptibility to infection. CR is lowered by remission-inducing treatment (radiation and/or chemotherapy) in leukaemia, but more severely by certain antibiotics. Development (by selection or transfer) of resistance to these antibiotics may lead to overgrowth and penetration of the mucosal lining by the overgrowing (potentially) pathogenic bacteria. Other antibiotics however, if sufficiently dosed, have been found to eliminate (potential) pathogens selectively without decreasing CR. This selective decontamination of the gastrointestinal tract has been successfully used prophylactically in neutropenic patients but needs to be monitored bacteriologically. It should perhaps be used more widely in the hospital to control development and spread of antibiotic-resistant strains.

Anaerobiosis↗
PubMedDate not supplied

[Nuclease activity of microorganisms and control of auto-microflora state of operators in hermetically sealed environment].

A study was performed to investigate biological properties of pathogenic microorganisms (Shigella, Salmonella, Staphylococcus aureus) and potentially pathogenic microorganisms which were isolated from different people, i.e. clinically healthy people with normal microflora, somatically healthy patients with intestinal dysbacteriosis, and patients with acute intestinal diseases. The most important parameters of pathogenicity typical of the basic representatives of pathogenic microflora were DNA and/or RNA forming activity. The "critical" size of depolymerization zones of nucleic acids on dense nutrient media was found to be equal to 2 mm and greater from the colony edge. The critical size was shown to be significantly different in potentially pathogenic and normal intestinal microorganisms. Maximal microbial concentrations in the major biotopes of man were estimated to be: no more than 25%, 5% and 2% for nasal mucosa, back skin, and for the large intestine of the total amount of microorganism in the test. Verification of the method gave evidence that in can be applied for an alternative evaluation of automicroflora of the large intestine of operators in an enclosed environment. It is suggested that the normal parameters characteristic of clinically healthy people need to be verified and applied in space and undersea medicine.

Adult↗
PubMed2003

Comparative analysis of viral pathogens and potential indicators in shellfish.

Shellfish can be responsible of outbreaks of infectious diseases and current health measures do not guarantee the absence of viral pathogens in this product. Here we examine the presence of pathogenic viruses and potential indicators in shellfish in a comparative analysis.Sixty shellfish samples collected in three areas with different levels of faecal contamination were analysed for Escherichia coli, total coliforms, Clostridium perfringens, somatic coliphages, F-specific phages of RNA (F-RNA), bacteriophages infecting Bacteroides fragilis RYC2056, human adenovirus, enterovirus and hepatitis A virus (HAV). Viruses were eluted in a glycine buffer at pH 10. The overall percentage of viral pathogens detected was 47% for human adenoviruses, 19% for enteroviruses and 24% for HAV. Since all the samples positive for enterovirus and HAV were also positives for human adenovirus, the latter may be considered useful as a molecular index of viral contamination in shellfish. No significant differences in the bioaccumulation of bacteria and bacteriophages for oysters or mussels were observed. It was found that the probability of detection of any of the pathogenic virus decreases as the temperature of shellfish growing waters increases. However, the probability of detecting viruses increases when phages of B. fragilis are found. Although more data are needed in order to fulfil the need of viral indicators for controlling the presence of human viruses in shellfish, the obtained results indicate that phages infecting B. fragilis RYC2056 could be a suitable group of bacteriophages to be used as an indicator of the presence of viruses in shellfish.

Adenoviruses, Human↗
PubMed2000

Survey for psychrotrophic bacterial pathogens in minimally processed lettuce.

A total of 120 minimally processed, cut and packaged lettuce samples were purchased from retail supermarkets or provided by a salad production facility over an 8-month period. The samples were tested for total aerobic plate counts and for the presence of potentially pathogenic species belonging to the genera of Listeria, Aeromonas and Yersinia. The aerobic plate counts ranged from 103 to 109 colony forming units (cfu) g-1. Most samples (76%) contained between 105 and 107 cfu g-1 total aerobic bacteria. Listeria monocytogenes was isolated from three samples, Aeromonas hydrophila or Aeromonas caviae from 66 samples, and Yersinia enterocolitica from 71 samples. The pathogenic potential of Y. enterocolitica isolates was determined by screening for an array of biochemical, serological and genetic traits (heat-stable enterotoxin gene, the attachment and invasion gene locus, the invasin gene locus and the virulence plasmid). The Y. enterocolitica isolates lacked many of the phenotypic and genetic markers associated with virulence in primary pathogenic strains. As the roles of the reputed virulence factors of Aeromonas spp. in human infection are uncertain, the pathogenic potential of the Aeromonas isolates in lettuce remains unclear.

Aeromonas hydrophila↗
PubMed2004

Genesis of a highly pathogenic and potentially pandemic H5N1 influenza virus in eastern Asia.

A highly pathogenic avian influenza virus, H5N1, caused disease outbreaks in poultry in China and seven other east Asian countries between late 2003 and early 2004; the same virus was fatal to humans in Thailand and Vietnam. Here we demonstrate a series of genetic reassortment events traceable to the precursor of the H5N1 viruses that caused the initial human outbreak in Hong Kong in 1997 (refs 2-4) and subsequent avian outbreaks in 2001 and 2002 (refs 5, 6). These events gave rise to a dominant H5N1 genotype (Z) in chickens and ducks that was responsible for the regional outbreak in 2003-04. Our findings indicate that domestic ducks in southern China had a central role in the generation and maintenance of this virus, and that wild birds may have contributed to the increasingly wide spread of the virus in Asia. Our results suggest that H5N1 viruses with pandemic potential have become endemic in the region and are not easily eradicable. These developments pose a threat to public and veterinary health in the region and potentially the world, and suggest that long-term control measures are required.

Animals↗
PubMed1992

Microbial colonization and sperm--mucus interaction: results in 1000 infertile couples.

After screening a large series of infertile patients (n = 1000 couples), potentially pathogenic microorganisms were identified in genital secretions of the majority of couples. None of the patients displayed signs or symptoms of infection of the lower genital tract. In semen specimens and cervical swabs, mycoplasmas were found in 18 and 12%, potentially pathogenic aerobic bacteria in 50 and 31%, additionally commensal aerobes in 38% and 25%, respectively. The microbial pattern showed great variability with polymicrobial growth most common. The rate of cultures positive for potentially pathogenic anaerobes was markedly influenced by the transport conditions. In endocervical material, Herpes simplex virus (HSV) was identified in 4.5%. Yeasts were found in the posterior vaginal fornix in 10%. Concerning both partners, there were only 10 couples (1%) from whom microorganisms in genital secretions could not be isolated, not including lactobacilli in females. This high prevalence of microbes and the low number of leukocytes indicate colonization rather than infection. When the microbial findings from both partners were analysed with regard to the outcome of sperm-cervical mucus penetration testing in vitro, which was performed simultaneously, no significant correlation was found. Furthermore, microbial prevalence did not differ between couples with 'explained' and 'unexplained' infertility. The results of this study demonstrate that in patients without symptoms of genital tract infection, microbial colonization is of minor importance for sperm--mucus interaction and that extensive microbial screening should be preferentially performed in cases of poor sperm and/or mucus function.

Adult↗
PubMed1999

The effect of cigarette smoke on adherence of respiratory pathogens to buccal epithelial cells.

Smoking is associated with an increased risk of respiratory tract infection in adults. In children, exposure to cigarette smoke is a risk factor for respiratory tract infection and bacterial meningitis: Active smoking and passive exposure to cigarette smoke is also associated with carriage of some potentially pathogenic species of bacteria in both adults and children. The aims of the study were to determine the effect of active smoking on: (1) bacterial binding to epithelial cells; (2) expression of host cell antigens that act as receptors for some species; and (3) the effects of passive exposure to water-soluble components of cigarette smoke on bacterial binding. Flow cytometry was used to assess binding to buccal epithelial cells of the following species labelled with fluorescein isothiocyanate: Neisseria meningitidis, Neisseria lactamica, Streptococcus pneumoniae, Bordetella pertussis, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus. Flow cytometry was also used to assess expression of host cell antigens which have been identified as bacterial receptors. For each species, binding to cells of smokers was significantly higher than to cells of non-smokers; however, expression of host cell antigens was similar on epithelial cells of both groups. Non-dilute cigarette smoke extract reduced binding of bacteria to epithelial cells, but dilutions between 1 in 10 and 1 in 320 enhanced binding. We conclude that smokers might be more densely colonised by a variety of potentially pathogenic bacteria. The enhanced bacterial binding to epithelial cells of smokers is not related to enhanced expression of host cell antigens that can act as receptors for some species, but possibly to components in the smoke that alter charge or other properties of the epithelial cell surface. Passive coating of mucosal surfaces with components of cigarette smoke might enhance binding of potentially pathogenic bacteria.

Adult↗
PubMed1992

Genetic analysis of self-associating immunoglobulin G rheumatoid factors from two rheumatoid synovia implicates an antigen-driven response.

Although much has been learned about the molecular basis of immunoglobulin M (IgM) rheumatoid factors (RFs) in healthy individuals and in patients with mixed cryoglobulinemia and rheumatoid arthritis, little is known about the genetic origins of the potentially pathogenic IgG RFs in the inflamed rheumatoid synovia of patients. Recently, we generated from unmanipulated synovium B cells several hybridomas that secreted self-associating IgG RFs. To delineate the genetic origins of such potentially pathogenic RFs, we adapted the anchored polymerase chain reaction to rapidly clone and characterize the expressed Ig V genes for the L1 and the D1 IgG RFs. Then, we identified the germline counterparts of the expressed L1 IgG RF V genes. The results showed that the L1 heavy chain was encoded by a Vh gene that is expressed preferentially during early ontogenic development, and that is probably located within 240 kb upstream of the Jh locus. The overlap between this RF Vh gene and the restricted fetal antibody repertoire is reminiscent of the natural antibody-associated Vh genes, and suggests that at least part of the "potential pathogenic" IgG RFs in rheumatoid synovium may derive from the "physiological" natural antibody repertoire in a normal immune system. Indeed, the corresponding germline Vh gene for L1 encodes the heavy chain of an IgM RF found in a 19-wk-old fetal spleen. Furthermore, the comparisons of the expressed RF V genes and their germline counterparts reveal that the L1 heavy and light chain variable regions had, respectively, 16 and 7 somatic mutations, which resulted in eight and four amino acid changes. Strikingly, all eight mutations in the complementarity determining regions of the V gene-encoded regions were replacement changes, while only 6 of 11 mutations in the framework regions caused amino acid changes. Combined with L1's high binding affinity toward the Fc fragment, these results suggest strongly that the L1 IgG RF must have been driven by the Fc antigen.

Amino Acid Sequence↗