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At least 253 records · Page 14Linked to original sources
PubMed1994

Detection of antibody-coated bacteria in expectorated sputum for diagnosis of lower respiratory infections.

We evaluated antibody-coated bacteria (ACB) in expectorated sputum to discriminate contaminating or colonizing organisms from true pathogens. We examined 60 expectorated sputum samples from 51 patients with lower respiratory infections (chronic obstructive pulmonary disease 25, pneumonia 20, purulent tracheobronchitis 6). All samples were examined with quantitative culture and immunofluorescent demonstration of ACB. From the results of quantitative culture, we divided specimens into pathogen-isolated and pathogen-free samples. Among pathogen-isolated samples, in which we isolated accepted pathogenic organisms at > or = 10(7) colony-forming units per ml, 16 of 23 samples were ACB-positive (69.5%). In contrast, among pathogen-free samples, in which we isolated accepted pathogens at < 10(7) colony forming units per ml or only upper respiratory flora, only 3 of 37 samples were ACB-positive (8.1%). The ACB-positive rate was significantly higher in pathogen-isolated than in pathogen-free samples (P < 0.001). Consequently, detecting ACB in expectorated sputum shows good potential as another criterion for distinguishing contaminating or colonizing organisms from true pathogens.

Adult↗
PubMed1994

Antimicrobial susceptibility of nasopharyngeal isolates of potential pathogens recovered from infants before antibiotic therapy: implications for the management of otitis media.

Antimicrobial susceptibility was determined for strains of Streptococcus pneumoniae, nontypable Haemophilus influenzae and Moraxella catarrhalis recovered from the nasopharynxes of children followed from birth. The bacteria tested were the first potential pathogens isolated from each child before any treatment with antibiotics. Minimal inhibitory concentrations of commonly used oral antibiotics demonstrated the following overall rates of resistance for (1) S. pneumoniae: penicillin 1.2% (intermediate susceptibility 4.8%), trimethoprim-sulfamethoxazole 20%; (2) nontypable H. influenzae: ampicillin 32%, cefaclor 17%; (3) M. catarrhalis: ampicillin 90%, trimethoprim-sulfamethoxazole 19%. Antibiotic regimens used for treatment of otitis media may have to be evaluated in light of changing antibiotic susceptibilities.

Anti-Bacterial Agents↗
PubMed1987

Isolation of pathogen-synthesized fraction that elicits phytoalexins in lucerne (Medicago sativa L.).

The production of phytoalexins by lucerne cultivars Dupuits (susceptible to Verticillium wilt) and Maris Kabul (resistant to Verticillum wilt) in response to substances (= elicitors) produced by pathogenic and non-pathogenic isolates of Verticillium albo-atrum was investigated. The elicitors are produced in culture filtrates from log-phase and past log-phase stages. The elicitors were isolated by gel-filtration and found to contain both protein and carbohydrate. They were found to be thermostable and non-dialyzable and proved to be sensitive to protease and sodium hydroxide treatment which suggests that they are glycoproteins. There was no evidence of specificity of the elicitors.

Cells, Cultured↗
PubMed2000

Production of thaxtomin A by two species of Streptomyces causing potato scab.

A total of nine isolates of streptomycetes were isolated from scab lesions on potato tubers. Five of nine isolates were pathogenic on potato minitubers. Four of the pathogenic isolates produced thaxtomin A (ThxA) in infected tuber tissues. The lesion surface areas inducing ThxA were highest in treatment of the minitubers with an extract of OMB inoculated with S-66 and S-67, intermediate with that inoculated with S-64 and lowest with S-63. The pathogenic isolates were identified by gray aerial mycelia, melanin pigment productivity, the type of spore chain morphology and carbon utilization as S. scabies strains S-63, S-64 and S-68, and S. acidiscabies strains S-66 and S-67. Strains S-63 and S-64 produced 0.65 and 1.60 mg ThxA per L of OMB, respectively, strains S-66 and S-67 producing similar amounts, viz. 2.36 and 2.10 mg/L, respectively. The optimal temperature for production (by both species) was 28 degrees C. Production of ThxA by S. scabies strain S-64 and S. acidiscabies strain S-66 was suppressed at least 50-fold at 0.5 and 0.3% of glucose, respectively. Fructose enhanced the production by both species.

Fructose↗
PubMed2005

Superficial fungal infections seen at the National Skin Centre, Singapore.

UNLABELLED: Cutaneous fungal infections are common in Singapore. The National Skin Centre is a tertiary referral centre for dermatological diseases in the country, and sees more than 2,500 cases of superficial fungal infections annually. AIM: This study analyses data collated from the centre's medical record office as well as fungal culture results from the mycology laboratory. RESULTS: From 1999 to 2003, there were a total of 12,903 cases of superficial fungal infections seen at the centre. The majority of patients (n=9335) (72.3%) were males. The most common infection was tinea pedis (n=3516) (27.3%), followed by pityriasis versicolor (n=3249) (25.2%) and tinea cruris (n=1745) (13.5%). Candidal infections were also common (n=1430), the majority of which were cases of candidal intertrigo. There were very few cases of tinea capitis, which is uncommon in Singapore. The number of cases of onychomycosis has shown a rising trend over the past 5 years. Trichophyton rubrum was the most prevalent fungal pathogen isolated from all cases of superficial fungal infections of the skin, except for tinea pedis, where Trichophyton interdigitale was the most frequently isolated organism. Dermatophytes remain the most commonly isolated fungal pathogens isolated in toenail onychomycosis, whilst Candida species accounted for the majority of isolates in fingernail onychomycosis. CONCLUSION: Current epidemiologic trends of superficial fungal infections in Singapore show some similarities to recent studies from the United Kingdom and United States.

Candidiasis, Cutaneous↗
PubMed1969

Sensitivity of freshly isolated bacterial pathogens to certain antibiotics and nitrofurazone.

The results of antibiotic tests on bacterial pathogens freshly isolated from avian tissues and bovine milk are presented. Coliform isolates from the avian species showed an increased resistance to antibiotics while those which produced bovine mastitis had remained generally more sensitive. The staphyloccoci and streptococci isolated from bovine milk showed an increase in resistance to most of the antibiotics tested. The indiscriminate administration of antibiotics to livestock and poultry has no doubt encouraged the development of resistant forms of bacteria and has made treatment with such products less effective.

Animals↗
PubMedDate not supplied

The multiplication of three different isolates of group B streptococci in pregnant mice.

The ability of three streptococcal isolates of different pathogenicity to multiply in the tissues of pregnant mice was investigated following intravenous injection. The highly pathogenic isolate multiplied most rapidly whilst the isolate of low pathogenicity showed the least rapid growth within the observation period of 24 hours. The greatest concentration of streptococci per gram of tissue was found in the placentae of mice injected with the highly pathogenic and moderately pathogenic isolates when compared with the concentration of livers and spleen. Fetal infection did not occur within 24 hours of intravenous injection of the isolates but retarded fetal growth and infection was demonstrable five days after the injection. The isolate of moderate pathogenicity infected a greater proportion of the fetuses than the isolates of low pathogenicity. It is suggested that the outcome of streptococcal infections by the ability of isolates to multiply in host tissues.

Animals↗
PubMed1997

Adherence of Candida albicans strains isolated from AIDS patients. Comparison with pathogenic yeasts isolated from patients without HIV infection.

The adherence of yeasts to oral mucous cells is one of the main characteristics of the pathogenicity of this fungus. We studied adherence by means of a radiometric test to improve the method. We compared a sample of 40 strains of Candida albicans isolated from the buccal mucosa of HIV-infected patients with 40 strains isolated from non-HIV patients. We found that buccally isolated C. albicans strains from patients in the initial stages of AIDS adhered to oral mucous cells less than the buccally isolated C. albicans strains from subjects without HIV infection. Adherence among the strains of HIV patients increased with the disease stage until it exceeded that of the normal subjects in proportion to the decrease in the CD4/CD8 ratio. The selection of resistant strains by the preliminary antifungal treatments gave us a partial explanation for this increase. Further research should be carried out to compare these results with those obtained from atypical strains and species with high pathogenic potential, such as Candida dubliniensis, which is frequently isolated from advanced AIDS, in order to prevent systemic infections in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Chromosome-based molecular characterization of pathogenic and non-pathogenic wheat isolates of Pyrenophora tritici-repentis.

The ToxA gene of Pyrenophora tritici-repentis encodes a host-selective toxin (Ptr ToxA) that has been shown to confer pathogenicity when used to transform a non-pathogenic wheat isolate. Major karyotype polymorphisms between pathogenic and non-pathogenic strains, and to a lesser extent among pathogenic strains, and among non-pathogenic strains were identified. ToxA was localized to a 3.0 Mb chromosome. PCR-based subtraction was carried out with the ToxA chromosome as tester DNA and genomic DNA from a non-pathogenic isolate as driver DNA. Seven of 8 single-copy probes that originated from the 3.0 Mb chromosome could be assigned to a 2.75 Mb chromosome of a non-pathogenic isolate. Nine different repetitive DNA probes originated from the 3.0 Mb chromosome, including sequences that correspond to known fungal transposable elements. Two additional single-copy probes that originated from a 3.4 Mb chromosome were unique to the pathogens and they correspond to a peptide synthetase gene. Our findings suggest substantial differences between pathogenic and non-pathogenic isolates of P. tritici-repentis.

Ascomycota↗
PubMed1982

Evaluation of the antimicrobial removal device when used with the BACTEC blood culture system.

A study to determine the value of the Antimicrobial Removal Device (ARD) used in conjunction with radiometric detection of bacteremia using three media was conducted. During a 12-month period, 622 duplicate ARD/BACTEC blood-culture sets were collected. There were 88 positive cultures that yielded 68 pathogenic isolates and 28 probable contaminant isolates. When all patients were considered, 31 pathogenic isolates were detected by both systems, 25 pathogenic isolates were detected faster or only by the BACTEC system, and 12 pathogenic isolates were detected faster or only when the ARD was employed. This difference is statistically significant (P less than 0.05). Thus, the standard BACTEC blood-culture system using three different media was superior to the same BACTEC system using ARD-processed blood specimens. When only patients receiving antimicrobial therapy were considered, there were more pathogenic isolates detected from unprocessed blood than from blood processed in the ARD; however, this difference was not statistically significant. In conclusion, there appears to be no advantage to using the ARD system in conjunction with the three-bottle BACTEC blood-culture system.

Adult↗
PubMed1990

Identification of a pathogenic isolate-specific 30,000-Mr antigen of Entamoeba histolytica by using a monoclonal antibody.

A monoclonal antibody (MAb) produced against trophozoites of Entamoeba histolytica strain HM-1:IMSS, reacted with all of 42 isolates and 4 clones showing pathogenic zymodeme (Z) patterns, i.e., Z-II, Z-II alpha-, Z-II (glucose phosphate isomerase: gamma +), Z-VII, Z-VII (glucose phosphate isomerase: alpha lack, gamma +), Z-XI, Z-XIV, and Z-XIX, regardless of culture conditions, geographical origins, or host symptoms in an indirect fluorescence antibody test. In contrast, the MAb failed to react with 14 isolates possessing nonpathogenic zymodemes Z-I and Z-VIII and did not react with other enteric protozoan parasites, such as E. histolytica-like Laredo, Entamoeba hartmanni, Entamoeba coli, Endolimax nana, Dientamoeba fragilis, Trichomonas hominis, and Giardia lamblia. Western immunoblotting analysis showed that the molecular weight of the antigenic component recognized by the MAb was exclusively 30,000 in pathogenic isolates of different zymodemes. These results suggest that the 30,000-molecular-weight antigen is a marker of pathogenic isolates and that the indirect fluorescent-antibody test with the MAb is useful for the accurate discrimination of pathogenic amebae.

Animals↗
PubMed2004

[The pathogens and their antibiotic sensitivities in hospital-acquired pneumonia cases].

Dynamic precautions in the early diagnosis and treatment of hospital acquired pneumonias are necessary because of their high mortality. In these patients, invasive diagnostic approaches may be needed since clinical and radiological findings and other non-invasive approaches frequently fail to establish the diagnosis. Thirty eight patients were prospectively included in the study. Average age of patients was 45.5 +/- 16.4 years; 31 were males (81.6%) and 7 (18.4%) were females. Pneumonia was detected in 9 (23.7%) cases during the first five days and in 29 (76.3%) cases after the fifth day of admission to the hospital. Bronchoscopic interventions diagnostic purpose were carried out in 25 (65.8%) patients. The culture results were negative in 7 (18.4%) cases. While more than one pathogen was determined on the cultures of 16 (42.1%) patients only one pathogen was isolated in the cultures of 15 (39.4%) cases. The frequently isolated pathogen on cultures was Staphylococci (45.4%). Other pathogens were Enterobacter spp., Pseudomonas spp., Escherichia coli, Serratia and Streptococcus pneumoniae according to their frequency on cultures. High resistance rates to the third generation cephalosporins were determined. Eleven of 17 deaths in 38 pneumonia cases were attributable to pneumonia. As a conclusion, isolation of pathogen and antibiotic resistance should be determined in the cases with hospital acquired pneumonia. Invasive diagnostic interventions were not avoided when necessary. Although pro-BAL and PSB methods were expensive, their use in selected cases may prevent unnecessary antibiotic use and contribute to a decrease in mortality rate.

Anti-Bacterial Agents↗
PubMed1992

Isolation of pathogenic strains of Haemophilus somnus from the female bovine reproductive tract.

The prevalence of Haemophilus somnus in the genital tract of slaughtered and live cows in southern Ontario was investigated. The vagina and uterus of slaughtered cows were swabbed separately. Live cows were examined and sampled in two field surveys: Centre A and Centre B. In the former, aspirated mucus secretions and in the latter, specimens obtained by guarded swabbing were examined bacteriologically. Haemophilus somnus was isolated from 28 genital tracts of 461 slaughtered (6.1%), and seven of 199 live (3.5%) cows during the centre B survey. The isolates were recovered from both normal and diseased reproductive tracts. Fourteen strains isolated from genital organs were examined for pathogenicity in vivo to test the occurrence of pathogenic isolates. In the initial stage of the in vivo study on pathogenicity, each of the fourteen isolates was examined on one calf using an intracisternal inoculation. Subsequently, one pathogenic and one nonpathogenic strain were inoculated into five calves each to statistically confirm their pathogenic potential. Of 14 genital isolates of H. somnus examined in an intracisternal calf assay, six (43%) caused a fatal peracute neurological disease, while eight were nonpathogenic. A comparative pathological study of pathogenic and nonpathogenic isolates showed that the former caused a severe fatal suppurative meningoencephalitis whereas the latter caused no lesions whatsoever or a mild leukocytic leptomeningitis. The salient data obtained in this study indicate that there are pathogenic strains of H. somnus in the genital tract of apparently normal cows as well as of those with inflammatory disease.

Abattoirs↗
PubMed2006

Isolation of pathogenic Listeria monocytogenes in faeces of wild animals in captivity.

The isolation of pathogenic Listeria spp. in faecal samples of captive wild animals was studied. Isolation of the pathogen was attempted from the samples by selective enrichment in University of Vermont Medium and plating onto Dominguez-Rodriguez isolation agar, PALCAM agar and modified McBride Listeria agar. Pathogenicity of the isolates was tested by Christie, Atkins, Munch Petersen test, phosphotidylinositol-specific phospholipase C assay, mice inoculation test and chick embryo bioassay. Listeria monocytogenes was isolated from eight (16%) of 50 faecal samples from six different mammals and one bird. Out of eight isolates, one isolate from jackal proved to be pathogenic by all the pathogenicity testing assays. PCR amplification of virulence genes suggested that the isolate was potentially pathogenic.

Animals↗
PubMed1984

Isolation of pathogenic bacteria from the nasopharynx of children with respiratory syncytial virus infection. Predictive value of chest roentgen examination and laboratory tests.

Potentially pathogenic bacteria were isolated from the nasopharynx in 33/66 hospitalized infants and children with verified respiratory syncytial virus (RSV) infection. The value of chest roentgenograms and blood counts for the prediction of concomitant bacterial infection was evaluated. Abnormal chest roentgenograms were found in 89% whether pathogenic bacteria were present or not. The most common finding was general hyperinflation of the lungs, with or without infiltrates. This occurred more frequently in the group with isolated RSV infection. Fever, leucocytosis and an elevated ESR were found during the illness in more than half the cases. These findings were more frequent in children who harboured potential pathogenic bacteria, though the difference was not significant. For optimal evaluation of a case all available information about it should be taken into consideration.

Bacterial Infections↗
PubMed1975

Pathogenic leptospiras isolated from Malaysian surface waters.

Pathogenic leptospiras (1,424) isolated from natural waters and wet soils in Malaysia comprised 29 different serovars (synonym serotypes). All except two of the serovars had been found previously in Malaysia. The exceptional serovars were werrasingha, an Autumnalis serogroup member originally isolated in Ceylon, and a new serovar designated evansi. Serovar evansi had serological affinities with serovar ranarum which was isolated from the kidney of a frog in Iowa. The large variety of serovars found in jungle areas was consistent with similar previous findings of diverse serovar infections in troops who had operated in Malaysian jungles.

Agglutination Tests↗
PubMed1993

Experimental infections of feline reovirus serotype 2 isolates.

Pathogenicity of feline reovirus serotype 2 isolates, Nos. 114 and 140 strains recovered from the feces of cats with diarrhea, was experimentally determined. Kittens orally inoculated with No. 114 strain did not show any clinical signs. Fecal consistency of kittens inoculated with No. 140 strain became rather diarrheic on the 3rd and 4th days after inoculation, but any other clinical abnormalities were not observed. Virus was excreted for the first five to six days after inoculation. Seroconversion was observed in the sera of all the inoculated kittens. Virus excretion and seroconversion were also noted in all contact control kittens. These results may indicate that feline reovirus serotype 2 is mildly pathogenic in cats.

Animals↗