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At least 325 records · Page 18Linked to original sources
PubMed1991

Prospective hospital study of community acquired lower respiratory tract infection in the elderly.

A prospective study of community acquired lower respiratory tract infection in the elderly was carried out over a 15-month period. During this time 127 consecutive admissions to two acute geriatric medical wards were studied. An aetiology was established in 77 (61%) of cases. Streptococcus pneumoniae was identified in 37% of patients. Haemophilus influenzae in 18% and Branhamella catarrhalis in 10%. Infection with Mycoplasma pneumoniae was found in only one episode and no cases of Legionella pneumophilia were diagnosed. A significant number of patients had multiple bacterial pathogens isolated: 18% of all bacterial pathogens isolated were ampicillin resistant. Fourteen patients died (11%). Lower respiratory tract infection is a frequent cause of hospital admission for those aged over 65 and is often regarded as a preterminal event. Adequately treated however, mortality is no higher than in the general population. Knowledge of the likely pathogens allows early and appropriate antibiotic therapy for these patients whether at home or on admission to hospital.

Aged↗
PubMedDate not supplied

Isolation and pathogenicity of mycoplasmas from geese.

Several mycoplasma isolation trials were performed on infertile goose eggs and goose embryos which died during incubation, as well as on geese of different ages. A total of 43 out of 110 goose eggs proved to be contaminated by mycoplasmas. Upon autopsy of birds which laid positive eggs, lesions were observed in the airsacs. Mycoplasmas could be isolated from their air sacs and oviduct. Four out of 15 strains examined biochemically and serologically with antisera prepared against all known avian mycoplasma species were identified as Acholeplasma laidlawii and A. axanthum, respectively. Two strains proved to be glucose-positive and arginine-negative and 9 were glucose-negative but arginine-positive. Some strains caused 50-80% mortality among embryos inoculated intra-yolk-sac at 12 days. In goslings inoculated at the age of 3 days with these strains, we observed fibrinous airsacculitis and peritonitis. By inoculating laying geese with one of the strains, we demonstrated decreasing egg production, increasing early-embryo mortality and egg transmission of mycoplasmas.

Acholeplasma↗
PubMed1975

[Comparison of the antibacterial activity of amikacin (BB-K8) with other aminoglycosides against pathogens recently isolated from clinical materials (author's transl) ].

We determined the antibacterial activity of amikacin against 1,277 strains of pathogenic bacteria isolated from clinical materials during 1974, including beta hemolytic streptococci, pneumococci, enterococci, Staphylococcus aureus, Staph. epidermidis, Escherichia coli, Klebsiella, Enterobacter, Citrobacter, Serratia, Proteus morganii and Pseudomonas aeruginosa, and compared the minimum inhibitory concentration (MIC) of this drug with gentamicin, dibekacin, tobramycin and kanamycin. 1)Antibacterial activity of amikacin against beta hemolytic streptococci, pneumococci and enterococci was as weak as the other four aminoglycosides, but against Staph. aureus, Staph. epidermidis, various groups of Enterobacteriaceae and Pseudomonas aeruginosa showed amikacin the good antibacterial activity as gentamicin, dibedacin and tobramycin, and also showed the good activity against kanamycin resistant strains. 2) Amikacin has the similar antibacterial spectrum as gentamicin, dibekacin or tobramycin, but its antibacterial activity is generally weakest among these four drugs. 3) On many strains tested the cross resistance is observed between amikacin and one of gentamicin, dibekacin and tobramycin, but several strains of Proteus morganii and Pseudomonas aeruginosa which have rather large MIC against gentamicin, dibekacin or tobramycin showed rather small MIC against amikacin.

Amikacin↗
PubMed2005

Pathogenic bacteria isolated from disease outbreaks in shellfish hatcheries. First description of Vibrio neptunius as an oyster pathogen.

Shellfish hatcheries are often affected by disease outbreaks. Three such episodes were investigated in different Galician hatcheries in order to establish the relationship between present microbiota and mortalities. Isolates were obtained from various parts of the hatcheries. Experimental tests for pathogenicity were carried out in microscale experiments using selected strains on Ostrea edulis larvae. The pathogenicity of 1 strain from each outbreak was demonstrated and shown to cause high mortalities (ranging from 98.5 to 100%) in 72 to 96 h after inoculation of larval cultures. All 3 strains belong to the genus Vibrio. One of the strains was identified as Vibrio neptunius and is the first description of this species as a molluscan pathogen. The other 2 strains showed low similarity with the Vibrio species analysed and may constitute new species within this genus.

Animals↗
PubMed1976

Selective medium for isolation of Treponema hyodysenteriae.

Pure cultures of six pathogenic isolates of Treponema hyodysenteriae, the colonic mucosal scrapings of seven pigs with acute swine dysentery, and feces from seven unaffected pigs were diluted in phosphate-buffered saline and plated on Trypticase soy agar with 5% citrated bovine blood (TSA) and TSA with various levels of spectinomycin (TSA-S). The plates were incubated at 42 degrees C in a vented GasPak jar with a cold palladium catalyst and either 80:20 H2-CO2 by evacuation and refilling or a H2-CO2 generator envelope. Viable cell counts of the six pathogenic isolates were not altered by plating on TSA-S with 400 mug of spectinomycin per ml (TSA-S400) as compared with TSA alone. Dilutions of colonic mucosal scrapings from seven pigs with acute swine dysentery showed numbers of T. hyodysenteriae to be unchanged when plated on TSA-S400. Flora other than T. hyodysenteriae present in acute swine dysentery was inhibited, on the average, by 99.99%. Plating of dilutions of feces of unaffected pigs on TSA-S400 showed inhibition of flora that averaged more than 99.9%. Pathogenicity of T. hyodysenteriae was not altered by isolation or serial passage on TSA-S400.

Animals↗
PubMed1982

[Experimental pathogenicity of isolates of Nocardia asteroides, Nocardia brasiliensis and Nocardia caviae from different sources].

The experimental pathogenicity of 14 isolates of Nocardia brasiliensis, 15 of N. asteroides, and 5 of N. caviae was investigated for the white Swiss mice inoculated intraperitoneally and in the foot pad, and for the guinea-pig and the hamster (Mesocricetus auratus) both inoculated intratesticularly. The guinea-pig was remarkably sensitive to N. asteroides, with an apparent relationship between pathogenicity and thermotolerance, confirming previous observations. Mice were in general less susceptible to this species. In both guinea-pigs and hamsters it was possible to observe typical granules with or without clubs. N. caviae was highly pathogenic for the guinea-pig and the hamster but no mycetomas were produced in the mice inoculated in the foot pad. Isolates of N. brasiliensis from natural sources were scarcely virulent for the different animals. Those of human origin produced significant lesions in the mice inoculated intraperitoneally with granules. Foot pad inoculation of mice with N. brasiliensis caused mycetomas in several animals.

Animals↗
PubMed1987

In vitro sensitivity of environmental isolates of pathogenic dematiaceous fungi to azole compounds and a phenylpropyl-morpholine derivative.

The in vitro sensitivity (minimum inhibitory concentrations; MICs) of 42 environmental isolates of pathogenic dematiaceous fungi to 7 azole compounds, viz. thiabendazole, ketoconazole, miconazole, econazole bifonazole, Bay n 7133, Bay 1 9139 and phenylpropyl-morpholine derivative, Ro14-4767/002 was studied by an agar dilution method using Emmon's Sabouraud dextrose agar (ESDA) as the culture medium. The isolates of Fonsecaea pedrosoi, Cladosporium carrionii, Exophiala jeanselmei and Ramichloridium subulatum were most sensitive to bifonazole with mean MICs of 0.06 microgram/ml or less; Phialophora verrucosa had an MIC of 0.05 microgram/ml to ketoconazole and Ro14-4767/002, respectively. Ochroconis sp had an MIC of 0.025 microgram/ml to Ro14-4767/002 and Cladosporium tennuisimum 0.39 microgram/ml to ketoconazole. Econazole and thiabendazole also showed good antifungal activity. The fungi were relatively resistant to the more recently developed azoles, viz. Bay n 7133 and Bay 1 9139, the later failing to inhibit C. tennuisimum at a concentration of 100 micrograms/ml. The minimum fungicidal concentrations (MFC) of the drugs were mostly within 2 to 8 fold of the MICs.

Animals↗
PubMed2026

Whole-genome characterization and phylogenetic placement of Fusarium oxysporum f. sp. vasinfectum isolates.

Fusarium wilt of cotton, caused by Fusarium oxysporum f. sp. vasinfectum (Fov), remains a persistent threat to cotton production worldwide. Among the known races, Fov race 4 and its extra-virulent variants cause particularly severe losses in Upland cotton. Although several Fov genome assemblies have been assigned to races, the genomic diversity and evolutionary relationships among pathogenic and non-pathogenic isolates associated with cotton outbreaks remain poorly understood at the whole-genome level. This study addressed these gaps by generating and comparing high-quality genome assemblies of four Fusarium isolates collected from Texas cotton fields: two pathogenic (TX17-24 and TX18-9) and two non-pathogenic (TX17-6 and TX18-6). Draft assemblies were generated using Oxford Nanopore long reads and polished with Illumina reads. Comparative genomic analyses showed that pathogenic isolates possessed larger genomes and more conserved orthologous families, whereas non-pathogenic isolates contained more unique genes. Analyses of predicted secreted effectors, transposable elements, and carbohydrate-active enzymes further distinguished pathogenic and non-pathogenic lineages, suggesting roles in virulence adaptation and genome plasticity. Phylogenomic analyses using k-mer-based, assembly- and alignment-free methods incorporated all available long-read Fov genomes and revealed substantial genetic diversity within races 1 and 4, clustering isolates into multiple sublineages. These findings show that Fov race diversification is underestimated when based on traditional classification schemes and may be shaped by host specialization, geographic separation, or horizontal gene transfer. This work advances our understanding of the genomic diversity and evolutionary dynamics of Fov and establishes a foundation for improved race identification and characterization of Fusarium wilt pathogenesis in cotton.

Fusarium oxysporum↗
PubMed1986

Comparative activity of ofloxacin with reference to bacterial strains isolated in in-patients and out-patients.

The in vitro activity of ofloxacin, a new quinolone derivative, was compared to that of other agents commonly in use against pathogens isolated in the community and in the hospital. None of the community or hospital strains isolated from urinary tract infection showed resistance to ofloxacin, while variable resistance was demonstrable with all other oral agents. Similar results were obtained with pathogens isolated from infected wounds originating in the community and in the hospital. Among pathogens isolated from the respiratory tract, ofloxacin was most active against Haemophilus influenzae, but less active than the penicillin-cephalosporin group against Streptococcus pneumoniae. Ofloxacin was active against all but one (Pseudomonas aeruginosa) blood culture isolates. Of 112 strains isolated from community-acquired infections, only one strain was ofloxacin-resistant while resistance to sulphamethoxazole-trimethoprim, ampicillin and doxycycline was 34%, 42% and 30%, respectively. Among 219 pathogens originating from nosocomial infections, 3.2% were resistant to ofloxacin compared to 56% for cefazolin, to 7.2% for cefotaxime, 15.8% for piperacillin and 22.3% for gentamicin. These results suggest that ofloxacin has great therapeutic potential for the therapy of bacterial infections originating both in the community and in the hospital.

Anti-Bacterial Agents↗
PubMed1989

Restriction fragment mapping of nontypable haemophilus influenzae: a new tool to study this middle ear pathogen.

Isolates of nontypable haemophilus influenzae (NTHI) recovered from paired nasopharyngeal (NP) and middle ear (ME) fluid cultures performed simultaneously on seven children with otitis media with effusion (OME) were studied by analysis of the restriction fragment patterns produced from total genomic DNA. This method provides a sensitive measure of the genetic similarities between strains. In the seven pairs examined, the NP and ME strains were indistinguishable from one another, whereas each pair was distinct from the other, except for two siblings in whom all four strains were identical. This information provides evidence that the pathogenesis of OME caused by NTHI involves spread of the bacteria from NP to the ME. Analysis of paired NP and ME isolates from three children with recurrent OME caused by NTHI indicated that the second episode was caused by the reinfection with a different strain rather than persistence and reemergence of the first strain. Finally, DNA analysis of strains from two siblings with concurrent OME suggested that person-to-person transmission of NTHI can occur among children. These findings suggest that at any one time the NTHI population in the NP is relatively homogenous, at least at the time of acute upper respiratory disease. Our observation that the strains present at the second episode of otitis media were different than the strains present in the first episode is consistent with strain replacement in the NP. Restriction fragment mapping analysis of genomic DNA of NTHI could provide a powerful tool for investigating the rate of turnover of the NTHI population in the NP.

Child, Preschool↗
PubMed2004

Dna probes for identification of leptospires and disease diagnosis.

A newly identified 1 kb DNA fragment amplified by PCR using (AG)8T inter-simple sequence repeats (ISSR) primer and a 631 bp segment of 16S rRNA ribosomal gene amplified by PCR using reported primers were labeled with a alpha32P dCTP for use as DNA probes. These probes were hybridized with DNA extracted from 19 standard pathogenic serovars, 3 standard saprophytic serovars, 33 pathogenic isolates (12 from patients, 1 from a tapwater source, and 20 from rodents), and 22 saprophytic isolates from environmental sources. The pathogen-specific 16S rRNA DNA probe specifically hybridized all 33 standard pathogenic serovars, to 13 pathogenic isolates. Similarly, the saprophyte specific 1 kb ISSR DNA probe specifically hybridized the 3 standard saprophytic serovars and the 22 saprophytic Leptospira isolates. The sensitivity of the 1 kb labeled saprophytic Leptospira specific DNA probe was 1.95 ng, and for the 16S rRNA pathogen specific probe 3.90 ng. The 16S rRNA gene segment DNA probe could also identify the leptospiremic stage in mice or guinea pigs infected experimentally with the pathogenic serovars australis, autumnalis or icterohaemorrhagiae. DNA probes therefore, owing to their high specificity and sensitivity, appear useful for easy, rapid, and reliable differentiation of pathogenic Leptospira strains and also hold promise for direct identification of organisms in blood samples to diagnose leptopsirosis.

Animals↗
PubMed1998

Characteristic infectivity of Sporothrix schenckii to mice depending on routes of infection and inherent fungal pathogenicity.

Isolates of Sporothrix schenckii were examined for their infectivity in BALB/c mice. The mice were injected with yeast forms of S. schenckii isolates differing in clinical source (human cutaneous lesions and pulmonary lesions), and fungal growth was determined at intervals in the footpad and visceral organs. After subcutaneous injection of approximately 10 colony forming units (cfu) of S. schenckii into the footpad, locally restricted fungal infection developed gradually. At the peak of the infection (3-4 weeks post-inoculation), viable fungal counts reached 102-106 cfu/footpad. Dissemination to other tissues and visceral organs was not observed. After intravenous or intraperitoneal injection of 106 cfu of yeast forms, three of four isolates from cutaneous sporotrichosis were unable to establish infection and were eliminated from blood and visceral organs. The development of systemic infection was observed only with S. schenckii isolates obtained from the human lung lesion. Thus, inherent properties of each clinical isolate and routes of infection were shown to be critical for the establishment of systemic infection in spite of the remarkably strong infectivity of S. schenckii to the cutaneous tissue.

Animals↗
PubMed1990

An immunogenic 30-kDa surface antigen of pathogenic clinical isolates of Entamoeba histolytica.

A 30-kDa surface antigen was identified by Western blots with human immune sera in all 15 isolates of E. histolytica from patients with invasive amebiasis (pathogenic) but not in 15 strains from asymptomatic patients (nonpathogenic). This antigen is highly immunogenic in naturally infected humans and was recognized by sera from 22 patients with invasive disease but not by sera from 13 patients harboring nonpathogenic strains. Its surface location is supported by its differential extraction in the detergent phase of Triton X-114 and by surface immunofluorescence of live trophozoites. Unlike previously described amebic surface antigens, this 30-kDa antigen is undetectable in axenic strains that were originally isolated from patients with invasive disease but have been adapted to grow without bacteria. Affinity-purified antibody to the 30-kDa antigen did not promote lysis of complement-resistant pathogenic strains. This surface antigen may be diagnostically important in the identification of pathogenic clinical isolates.

Amebiasis↗
PubMed2000

Induction of antibodies in guinea pigs and rhesus monkeys against the human immunodeficiency virus type 1 envelope: neutralization of nonpathogenic and pathogenic primary isolate simian/human immunodeficiency virus strains.

We have compared the abilities of human immunodeficiency virus type 1 (HIV-1) envelope V3 peptides and recombinant gp120 to induce antibodies that neutralize simian/human immunodeficiency viruses (SHIVs). SHIV-89.6 is a nonpathogenic SHIV that expresses the envelope protein of primary HIV-1 isolate 89.6. SHIV-89.6P, clone KB9, is a pathogenic SHIV variant derived from SHIV-89.6. Infection of rhesus monkeys with these SHIVs rarely induces anti-V3 region antibodies. To determine the availability of the gp120 V3 loop for neutralizing antibody binding on SHIV-89.6 and KB9 virions, we have constructed immunogenic C4-V3 peptides from these SHIVs and induced anti-V3 antibodies in guinea pigs and rhesus monkeys. We found that both SHIV-89.6 and KB9 C4-V3 peptides induced antibodies that neutralized SHIV-89.6 but that only SHIV-KB9 C4-V3 peptide induced antibodies that neutralized SHIV-KB9. Immunoprecipitation assays demonstrated that SHIV-KB9 C4-V3 peptide-induced antibodies had a greater ability to bind SHIV-KB9 envelope proteins than did antibodies raised against SHIV-89.6 C4-V3 peptide. We have used a series of mutant HIV-1 envelope constructs to map the gp120 determinants that affect neutralization by anti-V3 antibodies. The residue change at position 305 of arginine (in SHIV-89.6) to glutamic acid (in SHIV-KB9) played a central role in determining the ability of peptide-induced anti-V3 antiserum to neutralize primary isolate SHIVs. Moreover, residue changes in the SHIV-89.6 V1/V2 loops also played roles in regulating the availability of the V3 neutralizing epitope on SHIV-89.6 and -KB9. Thus, SHIV-89.6 and -KB9 V3 region peptides are capable of inducing neutralizing antibodies against these primary isolate SHIVs, although the pathogenic SHIV-KB9 is less easily neutralized than its nonpathogenic variant SHIV-89.6. In contrast to natural infection with SHIV-89.6, in which few animals make anti-V3 antibodies, C4-V3 peptides frequently induced anti-V3 antibodies that neutralized primary isolate SHIV strains.

Amino Acid Sequence↗
PubMed1982

Pathogenic bacteria isolated from infant feeding teats: contamination of teats used by illiterate and educated nursing mothers in Ile-Ife, Nigeria.

We assessed bacterial contamination of infant feeding teats among nursing mothers and identified pathogenic organisms that might be associated with the incidence of diarrhea. The incidence of diarrhea among the infants of illiterate mothers was fivefold that of infants of educated mothers. The vast majority of the illiterate mothers poorly sterilized their infants' feeding utensils. The most prevalent pathogenic organism isolated from the teats was enteropathogenic Escherichia coli, followed by Staphylococcus aureus. Unhygienic handling of feeds is an important factor in infantile diarrhea.

Bacteria↗
PubMed1977

[Characteristics of the antibiotic sensitivity of the pathogenic enterobacteria isolated from sick children].

The authors studied 2287 strains of pathogenic enteric bacteria, i.e. Shigella, enteropathogenic Escherichia and Salmonella freshly isolated from children with respect to their sensitivity to the most widely used antibiotics, i.e. levomycetin, tetracycline, streptomycin, monomycin, neomycin, kanamycin and erythromycin. Low sensitivity of these strains to the above antibiotics and their combinations was observed. In the treatment of children of this group it is necessary to take into account multiple antibiotic sensitivity of the isolates of the enteropathogenic bacteria.

Anti-Bacterial Agents↗
PubMed1998

Pathogenicity in isolates of Salmonella enterica serotype Enteritidis PT4 which differ in RpoS expression: effects of growth phase and low temperature.

Experiments with 2 wild type isolates of Salmonella enterica serotype Enteritidis PT4, which differed in RpoS expression, tolerance to certain hostile environments and pathogenicity, found that changes in in vitro acid, heat, or peroxide tolerance had no effect on the ability of the isolates to multiply in the spleens of C57/BL7/J mice infected orally. Thus, with the pathogenic RpoS-positive isolate, the infectivity of log phase chilled cells, which are profoundly acid-sensitive, was the same as that of non-chilled stationary phase cells which are acid-tolerant. Similarity the infectivity of the RpoS-negative, sensitive isolate, was not enhanced by increases in any tolerance. The ability to survive on surfaces, like infectivity, was also largely unaffected by either growth phase or cold exposure. These two attributes may thus be related and, given that the pathogenic PT4 isolate is capable of prolonged survival and the nonpathogenic isolate survives poorly, survival could serve as a potential marker of pathogenicity. Although the pathogenicity of the two isolates was very different, they showed an almost identical increase in acid tolerance following culture at pH 4.0 for up to 60 min.

Acids↗