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PubMed1998

Burkholderia pseudomallei infection in a Puerto Rican patient with chronic granulomatous disease: case report and review of occurrences in the Americas.

Burkholderia species, notably Burkholderia cepacia and Burkholderia gladioli, are important pathogens in patients with chronic granulomatous disease (CGD). Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in Southeast Asia and northern Australia but is a rare pathogen in other parts of the world. We describe the occurrence of B. pseudomallei infection in a Puerto Rican patient with CGD. This is one of only a small number of documented cases of melioidosis autochthonous to the Americas and is the first reported case of B. pseudomallei infection in a CGD patient from the Americas. We conclude that B. pseudomallei, like B. cepacia and B. gladioli, should be considered a potential pathogen in patients with CGD and that melioidosis should be considered in the differential diagnosis for ill residents of or travelers to Puerto Rico.

Americas↗

PubMed2005

Bacterial activity in cystic fibrosis lung infections.

BACKGROUND: Chronic lung infections are the primary cause of morbidity and mortality in Cystic Fibrosis (CF) patients. Recent molecular biological based studies have identified a surprisingly wide range of hitherto unreported bacterial species in the lungs of CF patients. The aim of this study was to determine whether the species present were active and, as such, worthy of further investigation as potential pathogens. METHODS: Terminal Restriction Fragment Length Polymorphism (T-RFLP) profiles were generated from PCR products amplified from 16S rDNA and Reverse Transcription Terminal Restriction Fragment Length Polymorphism (RT-T-RFLP) profiles, a marker of metabolic activity, were generated from PCR products amplified from 16S rRNA, both extracted from the same CF sputum sample. To test the level of activity of these bacteria, T-RFLP profiles were compared to RT-T-RFLP profiles. RESULTS: Samples from 17 individuals were studied. Parallel analyses identified a total of 706 individual T-RF and RT-T-RF bands in this sample set. 323 bands were detected by T-RFLP and 383 bands were detected by RT-T-RFLP (statistically significant; P < or = 0.001). For the group as a whole, 145 bands were detected in a T-RFLP profile alone, suggesting metabolically inactive bacteria. 205 bands were detected in an RT-T-RFLP profile alone and 178 bands were detected in both, suggesting a significant degree of metabolic activity. Although Pseudomonas aeruginosa was present and active in many patients, a low occurrence of other species traditionally considered to be key CF pathogens was detected. T-RFLP profiles obtained for induced sputum samples provided by healthy individuals without CF formed a separate cluster indicating a low level of similarity to those from CF patients. CONCLUSION: These results indicate that a high proportion of the bacterial species detected in the sputum from all of the CF patients in the study are active. The widespread activity of bacterial species in these samples emphasizes the potential importance of these previously unrecognized species within the CF lung.

Cystic Fibrosis↗

PubMedDate not supplied

Isolation of Vibrio and Pseudomonas from brown shrimp (Penaeus californiensis Holmes) intestine.

Bacteria of the genera Vibrio, Pseudomonas and Aeromonas were isolated from the intestine of apparently healthy brown shrimp (Penaeus californiensis Holmes) cultured in a tidal pond. Species from these genera of bacteria have been reported as shrimp pathogens and have been involved in human gastrointestinal disorders related to seafood consumption. Isolation was done first in Marine broth, then in selective media (TCBS, Cetrimide and MacConkey). The oxidase negative strains were discarded as insignificant to shrimp culture. The identification of oxidase positive strains was based in morphological and colonial characteristics, biochemical capabilities, and both salinity and temperature tolerance. API 20E system and fatty acid analysis were also included. Three potentially pathogenic bacteria, Vibrio parahaemolyticus, Vibrio furnissii and Pseudomonas putida were isolated and identified from healthy shrimp intestine.

Animals↗

PubMedDate not supplied

[Detection of Salmonella, Listeria spp., Vibrio spp., and Yersinia enterocolitica in frozen seafood and comparison with enumeration for faecal indicators: implication for public health].

Infections transmitted through consumption of contaminated seafood is a significant source of human morbidity. The aim of this study was to compare the detection of Salmonella, Listeria, Vibrio, and Yersinia enterocolitica in frozen seafood with results from enumeration of conventional faecal indicators. A total of 213 crustaceans or molluscs were purchased from local vendors in Italy: 74% were harvested in Italy, 25% from other European countries and 1% from outside Europe. Listeria spp. was isolated from 20% of samples, Vibrio spp. from 11%, Salmonella from 3% and Y. enterocolitica from 1%. Listeria species isolated were L. monocytogenes, L. innocua, L. welshimeri, L. ivanovii and L. seeligeri. Vibrio species isolated were V. alginolyticus and V. fluvialis. The most contaminated shellfish for both faecal indicator microrganism and pathogens were hen clams (6% contained Salmonella, 27% Listeria spp. and 3% Y. enterocolitica), while from 27% of shrimps Vibrio spp. was recovered. Higher levels of faecal indicators were recovered from samples harvested outside Europe, and 66% of samples harvested in Thailand were contaminated from Salmonella. Significant differences were found in the levels of contamination of seafoods depending upon the freezing regime, but there was a limited association between presence of potential pathogens (particularly Vibrio spp.) and conventional faecal indicators. Hence, we suggest reconsideration of current legal parameters to evaluate microbiological quality of seafood.

Feces↗

PubMed2004

Needlestick and sharps injury prevention.

Every day while caring for patients, nurses are at risk to exposure to bloodborne pathogens potentially resulting in infections such as HIV or hepatitis B and C. These exposures, while preventable, are often accepted as being a part of the job. In the United States, needlestick injuries have begun to decrease from an estimated one million exposures per year in 1996 to 385,000 per year in 2000. This decline has resulted from the protections afforded by the Occupational Safety and Health Administration's (OSHA) Bloodborne Pathogens Standard. Reasons for the success in decreasing needlestick and sharps injuries may be attributed to the elimination of needle recapping and the use of safer needle devices, sharps collection boxes, gloves and personal protective gear, and universal precautions. The prevention of needlestick injuries has made slow progress over the past 20 years since the HIV epidemic drew attention to the deadly nature of health care work and to protection of health care worker health and safety. In Africa, where the AIDS virus originated and where the prevalence of the human immunodeficiency virus (HIV) among hospitalized patients is highest in the world, attention has been directed only recently at protecting health care workers. Nurses, especially those infected from a preventable exposure, have been at the forefront of advocacy for prevention. This article includes a review about the hazard of exposure to bloodborne pathogens and epidemiology of occupational infection. The author discusses how to apply standard methods of occupational health and industry hygiene using the hierarchy of controls framework to prevent exposure to blood, and discusses evidence-based prevention and efficacy of particular control measures. Legislative progress and implementation of enforceable policy to protect health care workers is outlined.

Evidence-Based Medicine↗

PubMed2006

The weapon potential of human pathogenic fungi.

With the exception of Coccidioides spp., human pathogenic fungi are not found among lists of microbes with potential for biological warfare and bioterrorism against humans. However, many human pathogenic fungi are easily obtainable from the environment, are highly dispersible and can cause significant disease after inhalation with relatively low inocula. When the biological and pathogenic attributes of certain human pathogenic fungi are considered using a formula for calculating the relative weapon potential of a microbe it is as apparent that some organisms such as Coccidioides spp. are comparable to other microbes for which there is significant concern. Our analysis suggests that the current indifference to fungi as potential biological weapons against human populations is probably a perception engendered by their non-communicability, lack of history of use or development as biological weapons, and a relatively low incidence of symptomatic disease following natural infection. Awareness of the weapon potential of human pathogenic fungi is an important consideration for greater preparedness against the threat posed by biowarfare and bioterrorism.

Biological Warfare↗

PubMed2003

Viral zoonoses - a threat under control?

Despite intensive research and considerable effort to eradicate infectious diseases, modern medicine has failed to control many infectious diseases which have been thought to be easy to overcome with advances in medical science and technology. In fact, infectious diseases remain a dominant feature in public health considerations for the 21st century. Some infectious agents already known to be pathogenic have gained increasing importance in recent decades due to changes in disease patterns. Furthermore, many new, previously unknown infectious agents with a high pathogenic potential have been identified. Nearly all of these emergent disease episodes have involved zoonotic or species-jumping infectious agents. The complex interaction of factors like environmental and ecological changes, social factors, decline of health care, human demographics and behaviour influences the emergence of re-emergence of such diseases. Viruses, especially RNA viruses with their ability to adapt quickly to changing environmental conditions, are among the most prominent examples of emerging pathogens. In this review, we present the important examples of zoonotic viruses and discuss the factors playing a key role in the emergence and resurgence of these diseases.

Animal Husbandry↗

PubMedDate not supplied

[Microbiological aspects of the environment of deep sea habitats].

It is known that the hyperbaric environment facilitates selection of gram-negative microorganisms which acquire ecological predominance. From this point of view deep sea habitats can be regarded as a specific anthropotechnological niche for pathogenic microorganisms, particularly Pseudomonas aeruginosa A. aeruginosa colonization of the mucosa and skin of deep sea divers may result in infection manifestations which took place in chamber experiments when test subjects showed otitis externa and when virulent strains were isolated. It was demonstrated that the basic reservoir of P. aeruginosa was the water supply system. Hence, development of a reliable method for its disinfection should be of highest priority. One of the potential methods is SHF treatment. Another important approach is personal hygiene procedures preventing skin and mucosa contamination with potentially pathogenic microorganisms and procedures for increasing colonization resistance of divers with the aid of eubiotic therapy.

Atmosphere Exposure Chambers↗

PubMed2002

Bacterial adherence to pharyngeal cells: in vitro studies with alpha-haemolytic streptococci and Haemophilus influenzae.

We examined the adherence to pharyngeal cells of alpha-haemolytic Streptococci (AHS) and Haemophilus influenzae, representing normal flora and otitis media (OM) pathogens, respectively. The bacteria were incubated with epithelial cells brushed from the tonsils, adenoid or tubal orifice of children and adults. Adherence varied among the clinical isolates of AHS and H. influenzae. AHS adhered better to epithelial cells from a child compared with those sampled from an adult. The bacteria adhered better to cells from the tubal orifice compared with those sampled from the adenoid. The selective attachment of AHS to certain cells but not to others could not be correlated to apoptotic/necrotic cells versus viable cells. Incubation of epithelial cells with an isolate of AHS with good inhibitory activity against OM pathogens showed almost no adherence of bacteria to the epithelial cells after 12 and 24 h of incubation. If, however, an isolate of AHS with weak inhibitory activity was incubated with the cells, the bacteria that were attached to the epithelial cells from the beginning showed overgrowth in the broth and increasing attachment to the cells after 12 and 24 h. Thus the inhibitory activity of AHS could also affect the adherence of potential pathogens to the mucosal surfaces. The adherence pattern may at least partially explain the difference in susceptibility to OM between children and adults.

Adenoidectomy↗

PubMed2006

Gut flora and bacterial translocation in chronic liver disease.

Increasing evidence suggests that derangement of gut flora is of substantial clinical relevance to patients with cirrhosis. Intestinal bacterial overgrowth and increased bacterial translocation of gut flora from the intestinal lumen, in particular, predispose to an increased potential for bacterial infection in this group. Recent studies suggest that, in addition to their role in the pathogenesis of overt infective episodes and the clinical consequences of sepsis, gut flora contributes to the pro-inflammatory state of cirrhosis even in the absence of overt infection. Furthermore, manipulation of gut flora to augment the intestinal content of lactic acid-type bacteria at the expense of other gut flora species with more pathogenic potential may favourably influence liver function in cirrhotic patients. Here we review current concepts of the various inter-relationships between gut flora, bacterial translocation, bacterial infection, pro-inflammatory cytokine production and liver function in this group.

Antibiotic Prophylaxis↗

PubMedDate not supplied

Comparative evaluation of tissue trophism characteristics in turkeys and mallard ducks after intravenous inoculation of type A influenza viruses.

Ten avian type A influenza viruses consisting of seven waterfowl-origin, one pheasant-origin, and two turkey-origin viruses were evaluated for their pathogenicity potential after intravenous inoculation into domestic turkeys and mallard ducks (Anas platyrhynchos). The replicative abilities and tissue trophism properties of each virus isolate were examined in both species. The overall virus-isolation rate and histopathological lesion score were greater in the turkeys than in the ducks. The waterfowl-origin viruses caused more tissue damage in turkeys than in ducks but had a narrower tissue distribution range. The pheasant isolate was extremely pathogenic in turkeys but had limited distribution and little effect in ducks. The turkey isolates were more pathogenic in turkeys than in ducks. The pancreas was the most severely affected organ in turkeys, followed by kidney and liver. The spleen and bursa were the most commonly affected organs in ducks.

Animals↗

PubMed2001

Primary and recombinant HIV type 1 strains resistant to protease inhibitors are pathogenic in mature human lymphoid tissues.

Preserved peripheral CD4+ T cell counts despite virologic failure in patients undergoing protease inhibitor (PI)-containing antiviral regimens are a frequent occurrence in human immunodeficiency virus (HIV) disease. One hypothesis to explain the relative sparing of CD4+ T cells is that HIV strains exhibiting PI resistance concomitantly are attenuated in terms of cytopathicity for mature T cells. To test this hypothesis, we used a three-dimensional human tonsil histoculture microenvironment to assess the pathogenic potential of a panel of primary and recombinant HIV-1 strains derived from patients experiencing PI failure. All the viruses tested replicated efficiently in these cultures and, in some cases, better than comparable wild-type viral isolates. Furthermore, the PI-resistant strains depleted CD4+ T cells potently and comparably with wild-type isolates in these ex vivo lymphoid tissues. These results demonstrate that PI-resistant viruses are not inherently less pathogenic for mature T cells. Therefore, the sustained peripheral lymphocyte counts in patients with selective virologic failure may be due to specific defects in viral replication in other cell compartments or to an undefined host adaptation to viral infection during PI therapy.

CD4-Positive T-Lymphocytes↗

PubMed2000

General assessment of the influence of a municipal landfill site and environmental factors on the occurrence of keratinolytic fungi in soil.

The study was to generally determine the influence of a municipal landfill site and environmental factors on the distribution of keratinolytic fungi in soil. The landfill site in Sosnowiec was selected for examination. Keratinolytic fungi occurred abundantly in soils of the landfill site examined and its surrounding area. Of 495 soil samples (Petri dishes) examined, 379 (76.56%) were found to be positive for keratinolytic fungi. Altogether, 1131 strains from 26 species were isolated from the samples. Among the fungi, some species with pathogenic properties (Microsporum racemosum, M. cookei, M. gypseum, Aphanoascus fulvescens and Scopulariopsis brevicaulis) were recorded. The influence of environmental factors on the qualitative and quantitative composition of keratinolytic fungi in the soils was complex. Among these factors, exchangeable acidity (pH in 1 M KCl, in particular), faecal bacterial contamination and the level of water deficit in soil were the most important. The conclusion has been drawn that municipal landfill sites are the sources of potentially pathogenic fungi with keratinolytic properties.

Environment↗

PubMed2004

Implications of the evolution pattern of human T-cell leukemia retroviruses on their pathogenic virulence (Review).

Simian retroviruses pose a serious threat to public health, as two human pathogenic retroviruses, HIV and HTLV, have been already proved to originate from such non-human viruses. Therefore, studying their natural prevalence among wild non-human primates is important for planning strategies to prevent the emergence of additional human retroviral pathogens. This article is focused on tracing the origin and evolution of the human T-cell leukemia viruses HTLV-I and HTLV-II in comparison to that of the simian lymphotropic viruses STLV-I, STLV-II and STLV-L, which are phylo-genically classified into a common group called primate T-lymphotropic viruses (PTLV). Thus, HTLV-I and STLV-I are referred to as PTLV-I and HTLV-II and STLV-II as PTLV-II, whereas STLV-L, which is highly divergent from both HTLV types, comprises a third subgroup called PTLV-L. The phylogeny of PTLV indicates that both, HTLV-I and HTLV-II emerged from a simian origin, but their subsequent evolution continued in different patterns. HTLV-I includes 6 subtypes which evolved from STLV-I through several times of different geographic interspecies transmission between simian and human hosts. These repeated invasions to new primate species are likely to give rise to viral strains with increasing pathogenic potential. On the other hand, HTLV-II includes 4 subtypes which appear to originate from a common human ancestor virus that emerged from only one simian to human transmission, whereas the subsequent evolution of HTLV-II and STLV-II strains continued separately only within the Homo sapiens and Pan paniscus species respectively, without repeated interspecies jumps. Such evolution pattern likely involves less genetic changes and selection of viral strains with low pathogenic virulence that could co-exist with their hosts for long time. These different evolution patterns can explain the much wider implication of HTLV-I with human clinical disorders than HTLV-II. Of note, however, more recently HTLV-II started spreading much more rapidly through intravenous drug users to many geographical regions, with a 150-350 fold higher mutation rate than that of its previous strictly endemic strains. This change in the mode of the virus spread creates a serious risk for emergence of HTLV-II strains with higher virulence.

Animals↗

PubMed1997

Equine herpesvirus 1 mutants devoid of glycoprotein B or M are apathogenic for mice but induce protection against challenge infection.

Equine herpesvirus 1 (EHV-1) mutants devoid of the open reading frames (ORFs) of either glycoprotein (g) B or M were constructed and tested for their immunogenic potential in a murine model of EHV-1 infection. The mutant viruses were engineered using the virulent EHV-1 strain RacL11 or the modified live vaccine strain RacH by inserting the Escherichia coli LacZ gene into the viral ORFs. RacL11-infected mice showed signs typical of an EHV-1 infection, whereas mice infected with the EHV-1 gB- or gM-negative mutants or with RacH did not develop disease. No difference in the pathogenic potential of RacL11 gB- and gM-negative viruses was observed after application of either phenotypically completed or negative viruses. However, revertant RacL11 viruses in which the gB or gM gene had been restored caused EHV-1-related symptoms that were indistinguishable from those induced by RacL11. Mice that had been immunized with phenotypically negative gB- and gM-deficient EHV-1 were challenged with the RacL11 virus 25 days after immunization. Mock-immunized mice developed EHV-1 disease and high virus loads in their lungs were observed. In contrast, mice developed not exhibit EHV-1-caused disease. It was concluded (i) that deletion of either gB or gM abolished the virulence of strain RacL11 and (ii) that immunization with gB- or gM-negative EHV-1 elicited a protective immunity that was reflected by both virus-neutralizing antibodies and EHV-1-specific T-cells in spleens of immunized mice.

Animals↗

PubMed2002

Structural and functional aspects of the collectin SP-A.

Surfactant protein A (SP-A), member of the collectin family, is implicated in innate host defense of the lung. SP-A is a "pattern recognition molecule" and interacts with glycoconjugates on the surface of micro-organisms. It protects the lung by interacting with a wide variety of potential pathogens, including viruses, bacteria and fungi. This may result in enhanced killing and clearance by phagocytes. SP-A is a link between the innate and adaptive immune system because it directly affects lymphocyte proliferation and function. Although most extensively studied in the lung, SP-A is found in a number of other sites in the body. The presence of SP-A at these mucosal surfaces, which are in close contact with numerous potentially harmful micro-organisms, supports a more general role for this collectin in mucosal defense.

Animals↗

PubMed2004

PCR detection of hemolysin (vhh) gene in Vibrio harveyi.

The Vibrio harveyi hemolysin gene (vhh), which encodes for a virulence factor involved in pathogenicity to fish and shellfish species, may be targeted for species detection or strain differentiation. Primers designed for this gene were used in detection studies of V. harveyi strains from various hosts. One primer set among four tested, could amplify the expected gene fragment in PCR using templates from all 11 V. harveyi strains studied. Detection of the presence of the hemolysin gene could therefore serve as a suitable detection marker of Vibrio harveyi isolates potentially pathogenic to fish and shrimps.

Base Sequence↗

PubMed1989

The immunocompromised host.

Infection still remains the most common immediate cause of death in the immunocompromised host. Because of the decreased host defenses leading not only to an increased susceptibility to a variety of opportunistic pathogens (in particular the fungi) but also to a decreased host inflammatory response and resultant clinical findings, infections in these patients are difficult to diagnose. Skin lesions occur in up to a third of infections in compromised hosts and can often be the first presentation of a systemic illness. The broad scope of dermatologic manifestations of infection in compromised patients is reviewed based on four presumed underlying pathophysiologic mechanisms and on the vast array of potential pathogens that have been reported to date in the literature.

Humans↗