Biomedical subjects

Thomas R Fritsche

Publications and source records attributed to Thomas R Fritsche.

82 records · Page 5Linked to original sources

PubMed2003

Counting leukocytes in expressed prostatic secretions from patients with chronic prostatitis/chronic pelvic pain syndrome.

OBJECTIVES: The evaluation of WBCs in EPS is recommended for classifying patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) but no agreement has been reached on the optimal method. We sought to determine the relationship between the expressed prostatic secretions (EPS) leukocyte (WBC) count per high-power field (evaluated by a more quantitative wet mount method and the traditional gram-stained smear method used in clinical microbiology laboratories) and the EPS WBC concentration to determine whether quantitative methods are necessary for accurate patient classification. METHODS: EPS collected from 94 patients with CP/CPPS were evaluated by gram-stained smear, a standardized wet mount, and a hemocytometer method. RESULTS: The gram-stained smear detected EPS WBCs in 21 (22%) of 94 subjects compared with 78 (83%) by the standardized wet mount and 57 (60%) by the hemocytometer method. The gram-stained EPS WBC count correlated poorly with the WBC concentration by hemocytometer (R(2) = 0.051, P = 0.03). Although the standardized EPS WBC count correlated better with the concentration by hemocytometer, the correlation coefficient remained low (R(2) = 0.244, P <0.0001). CONCLUSIONS: The standardized wet mount proved superior to the gram-stained smear, but both methods lacked precision. Quantitative determination of the EPS WBC concentration by a counting chamber method proved to be the superior evaluation for research studies of CP/CPPS.

Body Fluids↗

PubMed2003

Comparative activity and spectrum of broad-spectrum beta-lactams (cefepime, ceftazidime, ceftriaxone, piperacillin/tazobactam) tested against 12,295 staphylococci and streptococci: report from the SENTRY antimicrobial surveillance program (North America: 2001-2002).

A contemporary collection of 12,295 North American isolates (2001-2002) consisting of Staphylococcus aureus (50%), coagulase-negative staphylococci (12%), Streptococcus pneumoniae (24%), beta-hemolytic streptococci (12%), and viridans-group streptococci (2%) were tested against broad-spectrum beta-lactams (cefepime, ceftazidime, ceftriaxone, imipenem, piperacillin/tazobactam) and comparator agents using a reference broth microdilution method to determine their continued effectiveness for empiric antimicrobial therapy. All isolates were very susceptible to vancomycin, linezolid and quinupristin/dalfopristin (>98%). Oxacillin-susceptible staphylococci were also highly susceptible to the tested beta-lactams (>98%) with the exception of ceftazidime (93%). beta-hemolytic streptococci were exquisitely susceptible (>99%) to penicillin and all other agents except for clindamycin (94%) and erythromycin (81%). Viridans group streptococci were routinely less susceptible than were other streptococci. S. pneumoniae remained susceptible to most agents (>91%) with the exceptions of erythromycin (74%) and penicillin (69%). Among beta-lactams tested against S. pneumoniae, ceftriaxone and cefepime continued to be very active against penicillin-susceptible (>99%) and intermediate (>98%) strains, but less active (80% and 82%, respectively) against penicillin-resistant isolates. These findings confirm that the newer cephalosporins (cefepime and ceftriaxone) among broad-spectrum beta-lactam agents have a spectrum of activity that remains comprehensive for the commonly isolated Gram-positive pathogens.

Drug Resistance, Bacterial↗

PubMed2003

Contemporary evaluation of the in vitro activity and spectrum of cefdinir compared with other orally administered antimicrobials tested against common respiratory tract pathogens (2000-2002).

Cefdinir is an oral cephalosporin approved by the Food and Drug Administration in 1997 for the treatment of acute exacerbation of chronic bronchitis, pharyngitis-tonsillitis, community-acquired pneumonia, acute maxillary sinusitis, and uncomplicated skin and skin structure infections in adults and adolescents, and acute otitis media, pharyngitis-tonsillitis, and uncomplicated skin and skin structure infections in children. Although cefdinir showed similar activity to other cephalosporins in the early studies, very limited data has been generated over the last decade. In this report, we summarize the contemporary in vitro activity and spectrum of cefdinir in comparison to numerous other orally administrated antimicrobials available for treatment of community-acquired respiratory infections. A total of 8,326 non-duplicate recent clinical isolates, including Haemophilus influenzae (3,438), Moraxella catarrhalis (1,688), and Streptococcus pneumoniae (3,200), were collected from 35 medical centers in North America during 2000 through 2002, and susceptibility tested by reference broth microdilution methods. Pneumococcal susceptibility patterns for beta-lactams and macrolides were also analyzed according to the year of isolation and the age group of the patients. Cefdinir had the greatest activity against H. influenzae among the cephalosporins tested with susceptibility rates of 97.1 to 99.0%. All of the agents tested had complete or near complete activity against M. catarrhalis. Against S. pneumoniae, cefdinir and other cephalosporins showed similar susceptibility patterns, but improved rates were observed in 2002 (78.5-79.4%) when compared to the previous monitored period (71.8-74.5%). This increase in susceptibility was mainly because of a declining the occurrence of high-level penicillin resistance (MIC >/=2 microg/ml) across all age groups. Macrolide resistance also decreased among S. pneumoniae in 2002 when compared to 2000 through 2001; however, resistance to levofloxacin continued to increase from 0.9% in 2000 to 1.4% in 2002. These results indicate a significant change in emerging beta-lactam resistance patterns (including cefdinir) with a decrease possibly influenced by greater pneumococcal vaccine use in children and the elderly. These rates of increased susceptibility could sustain and enhance the clinical activity of orally administered beta-lactams such as cefdinir.

Administration, Oral↗

PubMed2003

Clinical correlation of toxin and common antigen enzyme immunoassay testing in patients with Clostridium difficile disease.

OBJECTIVE: The aim of the present study was to assess the correlation of Triage Micro Clostridium difficile Panel and toxin B cytotoxicity assay with the clinical diagnosis of C. difficile diarrhea. METHODS: The subjects evaluated were 98 patients with diarrhea for whom stool was submitted for testing for C. difficile. Clinical symptoms prompting evaluation, laboratory values, comorbid illness, and treatment outcomes that provided clinical insight into the etiology of the diarrhea were recorded. These data were then reviewed by two experienced clinical gastroenterologists who were blinded to the results of the Triage enzyme immunoassay and cytotoxin B assay. The final diagnosis of C. difficile diarrhea was based on the patient's clinical evaluation and symptoms, treatment, and subsequent outcome. RESULTS: Of 98 patients evaluated, 33 were diagnosed with C. difficile diarrhea by clinical criteria. The toxin B assay displayed 88% sensitivity and 100% specificity and positive predictive value. The toxin A component of the Triage Panel displayed 45% sensitivity but 98% specificity and 94% positive predictive value. The common antigen had 97% sensitivity and 95% negative predictive value. Among the 45 patients with only a common antigen detected, the most common diagnoses for diarrhea were chemotherapy-related, antibiotic-related diarrhea, and graft versus host disease. CONCLUSIONS: Our data show that both the Triage Micro C. difficile Panel and cytotoxin B for C. difficile have a high positive predictive value and negative predictive value for C. difficile diarrhea. The Triage Micro C. difficile Panel provides a reasonable alternative to the cytotoxin B assay in the assessment of clinically relevant C. difficile. The Triage Micro C. difficile Panel is less labor intensive and less expensive than cytotoxin B assay. The panel approach improves on the individual assay performances by increasing sensitivity and negative predictive value. When both common antigen and toxin A are positive, the likelihood of C. difficile diarrhea is high; conversely, when both results are negative, the likelihood of C. difficile diarrhea is low.

Adolescent↗

PubMed2003

Six rapid tests for direct detection of Clostridium difficile and its toxins in fecal samples compared with the fibroblast cytotoxicity assay.

Clostridium difficile is one of the most frequent causes of nosocomial gastrointestinal disease. Risk factors include prior antibiotic therapy, bowel surgery, and the immunocompromised state. Direct fecal analysis for C. difficile toxin B by tissue culture cytotoxin B assay (CBA), while only 60 to 85% sensitive overall, is a common laboratory method. We have used 1,003 consecutive, nonduplicate fecal samples to compare six commercially available immunoassays (IA) for C. difficile detection with CBA: Prima System Clostridium difficile Tox A and VIDAS Clostridium difficile Tox A II, which detect C. difficile toxin A; Premier Cytoclone A/B and Techlab Clostridium difficile Tox A/B, which detect toxins A and B; and ImmunoCard Clostridium difficile and Triage Micro C. difficile panels, which detect toxin A and a species-specific antigen. For all tests, Triage antigen was most sensitive (89.1%; negative predictive value [NPV] = 98.7%) while ImmunoCard was most specific (99.7%; positive predictive value [PPV] = 95.0%). For toxin tests only, Prima System had the highest sensitivity (82.2%; NPV = 98.0%) while ImmunoCard had the highest specificity (99.7%; PPV = 95.0%). Hematopoietic stem cell transplant (HSCT) patients contributed 44.7% of all samples tested, and no significant differences in sensitivity or specificity were noted between HSCT and non-HSCT patients. IAs, while not as sensitive as direct fecal CBA, produce reasonable predictive values, especially when both antigen and toxin are detected. They also offer significant advantages over CBA in terms of turnaround time and ease of use.

Bacterial Toxins↗

PubMed2003

NmcA carbapenem-hydrolyzing enzyme in Enterobacter cloacae in North America.

An imipenem-resistant Enterobacter cloacae isolate was recovered from the blood of a patient with a hematologic malignancy. Analytical isoelectric focusing, inhibitor studies, hydrolysis, induction assays, and molecular sequencing methods confirmed the presence of a NmcA carbapenem-hydrolyzing enzyme. This first report of NmcA detected in North America warrants further investigation into its distribution and clinical impact.

Adult↗

PubMed2002

Obligate bacterial endosymbionts of Acanthamoeba spp. related to the beta-Proteobacteria: proposal of 'Candidatus Procabacter acanthamoebae' gen. nov., sp. nov.

All obligate bacterial endosymbionts of free-living amoebae currently described are affiliated with the alpha-Proteobacteria, the Chlamydiales or the phylum Cytophaga-Flavobacterium-Bacteroides. Here, six rod-shaped gram-negative obligate bacterial endosymbionts of clinical and environmental isolates of Acanthamoeba spp. from the USA and Malaysia are reported. Comparative 16S rDNA sequence analysis demonstrated that these endosymbionts form a novel, monophyletic lineage within the beta-Proteobacteria, showing less than 90% sequence similarity to all other recognized members of this subclass. 23S rDNA sequence analysis of two symbionts confirmed this affiliation and revealed the presence of uncommon putative intervening sequences of 146 bp within helix-25 that shared no sequence homology to any other bacterial rDNA. In addition, the 23S rRNA of these endosymbionts displayed one polymorphism at the target site of oligonucleotide probe BET42a that is conserved in all other sequenced beta-Proteobacteria. Intra-cytoplasmatic localization of the endosymbionts within the amoebal host cells was confirmed by electron microscopy and fluorescence in situ hybridization with a specific 16S rRNA-targeted oligonucleotide probe. Based on these findings, the provisional name 'Candidatus Procabacter acanthamoebae' is proposed for classification of a representative of the six endosymbionts of Acanthamoeba spp. studied in this report. Comparative 18S rDNA sequence analysis of the Acanthamoeba host cells revealed their membership with either Acanthamoeba 18S rDNA sequence type T5 (Acanthamoeba lenticulata) or sequence type T4, which comprises the majority of all Acanthamoeba isolates.

Acanthamoeba↗

PubMed2002

Laboratory diagnosis of Trypanosoma cruzi infection in a colony-raised pigtailed macaque.

An adult (57 months), male, pigtailed macaque (Macaca nemestrina) was screened for an AIDS-related research project and found to be positive on a B-cell lymphocyte culture for trypanosomes. Characterization of the trypanosome was done by using hemocultures, serology, and molecular techniques. Nucleic-acid amplification and sequencing of the nuclear repetitive sequence, kinetoplast DNA, and a fragment of the small subunit RNA gene confirmed that the trypanosome isolated was Trypanosoma cruzi and not T. rangeli, the only other trypanosome known to infect mammals in the New World. This represents the first naturally occurring case of Chagas' disease (American trypanosomiasis) in M. nemestrina, an Old World macaque, and may present an opportunity for development of an animal model of this human disease. The presence of under-recognized but enzootic T. cruzi infection in colony-raised M. nemestrina may have a significant impact on research programs, mandating effective screening of high-risk animals prior to protocol assignment.

Animals↗

PubMed2000

Neochlamydia hartmannellae gen. nov., sp. nov. (Parachlamydiaceae), an endoparasite of the amoeba Hartmannella vermiformis.

Free-living amoebae are increasingly being recognized to serve as vehicles of dispersal for various bacterial human pathogens and as hosts for a variety of obligate bacterial endocytobionts. Several Chlamydia-like Acanthamoeba endocytobionts constituting the recently proposed family Parachlamydiaceae are of special interest as potential human pathogens. In this study coccoid bacterial endocytobionts of a Hartmannella vermiformis isolate were analysed. Infection of H. vermiformis with these bacteria resulted in prevention of cyst formation and subsequent host-cell lysis. Transfection experiments demonstrated that the parasites were not capable of propagating within other closely related free-living amoebae but were able to infect the distantly related species Dictyostelium discoideum. Electron microscopy of the parasites revealed typical morphological characteristics of the Chlamydiales, including the existence of a Chlamydia-like life-cycle, but indicated that these endocytobionts, in contrast to Chlamydia species, do not reside within a vacuole. Comparative 16S rRNA sequence analysis showed that the endocytobiont of H. vermiformis, classified as Neochlamydia hartmannellae gen. nov., sp. nov., is affiliated to the family Parachlamydiaceae. Confocal laser scanning microscopy in combination with fluorescence in situ hybridization using rRNA-targeted oligonucleotide probes confirmed the intracellular localization of the parasites and demonstrated the absence of other bacterial species within the Hartmannella host. These findings extend our knowledge of the phylogenetic diversity of the Parachlamydiaceae and demonstrate for the first time that these endocytobionts can naturally develop within amoebae of the genus Hartmannella.

Animals↗

PubMedDate not supplied

Importance of understanding pharmacokinetic/pharmacodynamic principles in the emergence of resistances, including community-associated Staphylococcus aureus.

Pharmacologic parameters have been defined to predict efficacy in antimicrobial selection for the treatment of uncomplicated skin and skin structure infections (uSSSIs). Pharmacokinetics (PK) and pharmacodynamics (PD) are the bases for describing the in vivo behavior of antimicrobial agents. T>MIC is the duration of time that a pathogen is exposed to concentrations of antimicrobial agents that exceed the MIC of that particular organism. For antimicrobials with time-dependent activity (eg, penicillin and cephalosporins), the T>MIC needed to eradicate bacteria is generally 40% to 50% of the dosing interval. The most frequently prescribed oral antimicrobials for uSSSI are oral cephalosporins, amoxicillin/clavulanic acid, macrolides, anti-staphylococcal penicillins, and fluoroquinolones. The selected oral agent should display a broad spectrum of antimicrobial coverage, be able to be dosed once, or at most twice, a day, and show high levels of target attainment (> or = 90%) for eradicating the key pathogens associated with uSSSI. The recent emergence of methicillin-resistant Staphylococcus aureus (MRSA) in the community setting (CA-MRSA) is especially troublesome in that oral cephalosporins (and all other beta-lactam agents) are contraindicated, requiring alternative therapeutic approaches. While a common cause of cutaneous disease, including abscess formation, CA-MRSA has caused life-threatening necrotizing fasciitis and pneumonia. Treatment of abscesses produced by this pathogen consists of incision and drainage followed by an appropriate oral antimicrobial, based upon knowledge on the local resistance prevalence rates or as directed by culture and susceptibility testing.

Anti-Bacterial Agents↗