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Biomedical subjects

J D Klinger

Publications and source records attributed to J D Klinger.

At least 19 recordsLinked to original sources

Infection with a plasmid-free variant Chlamydia related to Chlamydia trachomatis identified by using multiple assays for nucleic acid detection.

Clinical samples in transport media from 40 patients exhibiting pathologies potentially caused by Chlamydia trachomatis infection were analyzed for chlamydial nucleic acid, and the results were compared with those of culture. Chlamydial culture was performed by a shell vial centrifugation method with HeLa 229 host cells. Polymerase chain reaction (PCR) assays were used to detect either regions on a 7.5-kb plasmid characteristic of C. trachomatis (plasmid-PCR) or a segment of the 16S rRNA genes (rRNA-PCR). All PCR results were confirmed by hybridization with probes for the specific amplified products in either a Southern or a dot blot format. An RNase protection (RNP) assay was used to detect genus-specific chlamydial 16S rRNA directly from the clinical samples. The PCR assays detected C. trachomatis but not other bacteria, including Chlamydia spp. C. trachomatis was isolated from six samples which were positive by the rDNA-PCR and plasmid-PCR assays. Five of the culture-positive specimens were positive by the RNP assay. Twenty-two samples were negative by all criteria. Surprisingly, nine samples were positive by rRNA-PCR and RNP assays only. Nucleic acid sequencing of the rRNA-PCR-amplified products indicated a close relationship between the variants and C. trachomatis. The data may indicate an unrecognized process in C. trachomatis infection or that these patients were infected by a variant strain of C. trachomatis which lacks the C. trachomatis-specific plasmid.

Animals

Granulocyte transfusions in septic adult and newborn rats: distribution of granulocytes and effect on peripheral blood and bone marrow.

Granulocyte transfusions are increasingly being used as therapy for newborns with sepsis and neutropenia. We injected either group B Streptococcus or phosphate-buffered saline solution intraperitoneally into adult and newborn rats. Human granulocytes, labeled with chromium 51, were transfused seven hours later. When the newborn rats were killed 13 to 19 hours after injection, they had 10(2) to 10(6) cfu/gm Streptococcus organisms in both lung and brain. Only one third of the adult rats had 10(2) to 10(4) cfu/gm Streptococcus organisms in either lung or brain. A greater proportion of the transfused granulocytes was present in lung and brain tissue of newborn rats, compared with adult rats (p less than 0.05), irrespective of infection. Granulocyte transfusion did not change the peripheral blood leukocyte count in adult rats but increased the count in newborn rats (p less than 0.05). The immature myeloid pool in the bone marrow of adult rats increased significantly with either infection or transfusion (p less than 0.01). The immature pool in newborn rats increased significantly only with infection (p greater than 0.001), although the combination of infection and transfusion also had a significant effect on the pool (p less than 0.01). Infection and both infection and transfusion, but not transfusion alone, significantly affected the mature myeloid bone marrow pool in adult and newborn rats (p less than 0.001). The depletion of the mature myeloid elements of the bone marrow in response to infection was dramatic in neonatal rats, compared with that in adult rats. Both transfused granulocytes and hematogenously spread streptococci lodge in the brains and lungs of neonatal rats more effectively than in those of adult rats.

Age Factors

A new colorimetric nucleic acid hybridization assay for Listeria in foods.

Non-isotopic colorimetric detection has been applied in a rapid nucleic acid dipstick hybridization assay for detection of Listeria spp. in food and environmental samples. The assay takes approximately 2.5-3 h following a two day broth and plate enrichment. Hybridization occurs between fluorescein labeled detector probes, poly(deoxyadenosine)-tailed capture probes, and Listeria-specific regions of 16 S ribosomal RNA. These target:probe complexes are captured on poly(deoxythymidine) coated plastic dipsticks. Detection is based on binding of horseradish peroxidase conjugated anti-fluorescein antibody to the hybridization complex, and enzyme-mediated color development. The colorimetric endpoint is read on a photometer at 450 nm. In these initial studies, 306 inoculated dairy, meat and seafood samples, and 200 environmental samples were tested. When compared with total culture results the hybridization assay had unconfirmed positive and false-negative rates of approximately 1.4-2.9% and 0.8-4.7%, respectively.

Colorimetry

Purification and characterization of an extracellular protease from Pseudomonas cepacia.

An extracellular proteinase (PSCP) produced by Pseudomonas cepacia was purified from culture supernatants by ammonium sulfate precipitation, anion exchange chromatography on DEAE-Sephacel, and G200 gel filtration chromatography. The protease has an apparent Mr of 34,000 by electrophoresis. Substrates cleaved by the protease include gelatin, hide powder, and collagen but not human immunoglobulin G (IgG), IgM, secretory IgA, or IgA. The enzyme had the characteristics of a metalloprotease, a pH optimum of 6, and a temperature optimum of 45 degrees C. Intratracheal instillation of purified PSCP into rat lungs produced a bronchopneumonia characterized by polymorphonuclear cell infiltration and proteinaceous exudation into large airways. Rats responded immunologically to active immunization with PSCP, but this response was not protective against subsequent lung infection with P. cepacia. PSCP was shown to have antigenic similarity with Pseudomonas aeruginosa elastase by an immunoblotting technique. Sera from 10 cystic fibrosis patients, with and without a previous history of P. cepacia colonization, were shown to possess antibody reactive against PSCP.

Amino Acids

Isolation of Listeria: a review of procedures and future prospects.

Recent documented foodborne outbreaks of listeriosis have underscored the need for improved isolation and identification procedures for Listeria. This review considers the development of selective enrichment media, various approaches to improving efficiency of isolation, and efforts to shorten enrichment periods. The application of simplified rapid nucleic acid hybridization techniques, in combination with improved cultural methods is the most promising of these approaches. Such methodological improvements should facilitate gathering data on important questions concerning the epidemiology of Listeria, and the natural history of listeriosis.

Animals

Colonization of the respiratory tract with Pseudomonas cepacia in cystic fibrosis. Risk factors and outcomes.

Between 1981 and 1983, some 85 patients with cystic fibrosis at Rainbow Babies and Childrens Hospital, Cleveland, developed colonization or infection of the respiratory tract with Pseudomonas cepacia. Twenty-nine (34 percent) of the colonized patients died; four were female patients with fulminant bacteremia with P cepacia prior to death. Case-control studies showed that increasing severity of underlying cystic fibrosis, increasing age, having a sibling with cystic fibrosis who was colonized with P cepacia, and previous hospitalizations were associated with increased risk of colonization. In patients with mild cystic fibrosis, no differences in clinical outcome were seen during the period of study; however, patients colonized with P cepacia who had moderate or advanced cystic fibrosis were hospitalized longer and died sooner after colonization, compared with control subjects with similar severity of cystic fibrosis. The excess mortality associated with such colonization varied in magnitude and trend according to the patient's sex and severity of underlying cystic fibrosis, reflecting the combined influence of colonization with P cepacia, sex, and severity of cystic fibrosis on the mortality of the patients. The source and mode of transmission of P cepacia were not determined, but the data suggest a possible nosocomial source. The results of this investigation showed that colonization with P cepacia most often affected patients with moderate or advanced cystic fibrosis and was associated with an adverse clinical outcome in these patients.

Adolescent

Pseudomonas cepacia: biology, mechanisms of virulence, epidemiology.

Pseudomonas cepacia, originally described as a plant pathogen, has emerged as an important cause of infection in altered hosts, particularly in the hospital setting. This organism's ability to survive and proliferate in a variety of solutions, medications, and even disinfectants and antiseptics has resulted in numerous clusters of common-source nosocomial infections. Many patients exposed to P. cepacia are merely colonized, but serious infections, including surgical and burn wound infections, bacteremia, meningitis, pneumonia, peritonitis, and urinary tract infections, are not rare. The virulence properties of this pathogen remain poorly characterized. Recently, P. cepacia has been reported in some cystic fibrosis centers as an increasingly frequent pulmonary pathogen. This trend has caused considerable concern because of reports of occasional cases of fulminant necrotizing pneumonia and bacteremia. Conversely, many patients with CF who become colonized with this organism have no ill effects. The epidemiology of P. cepacia in the CF population is unclear, but some patients probably acquire the organism from colonized siblings with CF. Circumstantial evidence suggests that the organism may also be acquired in the hospital. Treatment of infections is exceedingly difficult, particularly in patients with CF, because P. cepacia is resistant to a broad range of antibiotics.

Cross Infection

Association with phagocytic inhibition of anti-Pseudomonas aeruginosa immunoglobulin G antibody subclass levels in serum from patients with cystic fibrosis.

Serum from cystic fibrosis patients colonized with Pseudomonas aeruginosa specifically inhibits phagocytosis of P. aeruginosa by alveolar macrophages. Serum was examined for P. aeruginosa lipopolysaccharide-specific immunoglobulin G (IgG) subclass levels (by enzyme-linked immunosorbent assay) and for the effect on macrophage phagocytosis (by radiolabeled P. aeruginosa uptake). Sera from cystic fibrosis patients with no known P. aeruginosa colonization history had negligible amounts of lipopolysaccharide-specific IgG and a mean phagocytic enhancement of 5%. The sera of normal volunteers also had negligible amounts of lipopolysaccharide-specific IgG. Serum from cystic fibrosis patients with P. aeruginosa respiratory tract infections had substantial titers (range, 1:20 to 1:1,280) of lipopolysaccharide-specific IgG2, IgG3, and IgG4 and a mean phagocytic inhibition of 56%. However, these patients had low or absent titers of lipopolysaccharide-specific IgG1. No consistent variation in the level of individual IgG subclasses in the sera of colonized patients was observed, as determined by radial immunodiffusion. The results suggest that during P. aeruginosa infection phagocytosis-inhibitory activity develops coincident with production of lipopolysaccharide-specific IgG subclasses.

Adolescent

Pseudomonas cepacia: decrease in colonization in patients with cystic fibrosis.

The incidence and prevalence of Pseudomonas cepacia pulmonary colonization were noted to be increasing in patients with cystic fibrosis (CF). Previous work had indicated a greater prevalence of P. cepacia among siblings (with CF) of patients colonized by P. cepacia as well as an association of initial positive P. cepacia cultures with a hospitalization. Because of uncertainty regarding the source and mode of transmission, limited precautionary measures were instituted in 1983, including physical separation of hospitalized patients colonized with P. cepacia from non-colonized patients, reeducation of staff concerning basic infection control procedures, explanation to families regarding these precautionary efforts, and institution of separate summer camp sessions. Repeated environmental cultures throughout the hospital were negative for P. cepacia. Coincident with the institution of control measures, a sharp decline in incidence occurred (8.2% in 1983 versus 1.7% in 1984). These results are suggestive of patient-to-patient transmission. Because P. cepacia infections have been associated with shorter survival in some patients with CF, we will continue our current segregation measures.

Anti-Bacterial Agents

Ceftazidime therapy in patients with cystic fibrosis and multiply-drug-resistant pseudomonas.

The in vitro activity of ceftazidime against Pseudomonas aeruginosa and P. cepacia isolates from patients with cystic fibrosis was compared with that of other antipseudomonal drugs. Ceftazidime was as potent as imipenem against P. aeruginosa and the only drug effective against P. cepacia. An evaluation of the elimination kinetics of ceftazidime in 20 cystic fibrosis patients revealed an elimination half-life of 1.76 hours, an apparent distribution volume of 0.27 liters/kg, and a serum clearance rate of 133.9 ml/minute/1.73m2. Urinary recovery of ceftazidime was 87 percent within the first 24 hours after administration of the drug, with 65 percent recovered in the first two-hour fraction. Probenecid administration had no effect on the elimination kinetics of ceftazidime. Forty-three patients who had either shown no response to conventional therapy or had sputum Pseudomonas isolates that were susceptible only to ceftazidime received 75 courses of therapy. In 67 percent of these patients, the clinical response, when evaluated using an objective clinical efficacy scoring system, was considered favorable. Clinical failures were not associated with the development of drug resistance. Thus, ceftazidime can be recommended for the treatment of acute pulmonary exacerbations in patients with cystic fibrosis.

Adolescent

Some visual effects caused by the beverage kava.

Kava is a drink produced from the plant Piper methysticum and used as a social and ceremonial beverage on many South Pacific islands. Visual functions were measured in one subject following the taking of this drink. A reduced near point of accommodation and convergence, an increase in pupil diameter and disturbance to the oculomotor balance were noted. No changes were recorded in visual or stereoacuity or in ocular refractive error.

Adult

Occurrence and antimicrobial susceptibility of gram-negative nonfermentative bacilli in cystic fibrosis patients.

Isolation of nonfermentative gram-negative bacilli (other than Pseudomonas aeruginosa) from respiratory tract cultures of cystic fibrosis (CF) patients has increased in recent years. Species recovered include Pseudomonas cepacia, P. maltophilia, P. fluorescens/putida, P. alcaligenes, P. pseudoalcaligenes, P. stutzeri, Acinetobacter spp., Achromobacter xylosoxidans, Flavobacterium spp., and CDC groups IVe and Ve. Although colonization with most of these organisms is sporadic, P. cepacia (and to a lesser extent, P. maltophilia) is usually isolated consistently, and can be associated with significant clinical deterioration. Occurrence of P. cepacia in CF respiratory tract cultures obtained close to the time of death rose nearly ten-fold from 1979 to 1982. Strains representing all nonfermentative gram-negative species encountered were assayed for susceptibility to 17 newer antimicrobial agents. Ceftazidime, n-formimidoyl thienamycin, and aztreonam were most active; cefsulodin, ceforanide, and ceftriaxone were not active against these isolates.

Adolescent

Comparison of cefpiramide (HR-810) and four anti-pseudomonal beta-lactam agents against pseudomonas isolates from children with cystic fibrosis.

Cefpiramide (HR-810), ceftazidime, piperacillin, ticarcillin, and aztreonam were tested against tobramycin-sensitive and -resistant strains of Pseudomonas aeruginosa and tobramycin/amikacin-resistant isolates of Ps. cepacia recovered from the sputum of patients with cystic fibrosis. Against Ps. aeruginosa, none of the drugs inhibited 90% of the test strains at levels of less than 128 mg/l. Median minimal, inhibitory concentrations (MIC50) for all of the beta-lactam agents were lower for tobramycin-sensitive versus tobramycin-resistant isolates of Ps. aeruginosa. Ceftazidime was the most effective agent against Ps. cepacia. Aminoglycoside-resistance appears to be associated with significant beta-lactam resistance in Ps. aeruginosa isolated from the sputum of patients with cystic fibrosis.

Anti-Bacterial Agents

In-vitro activity of ciprofloxacin and other antibacterial agents against Pseudomonas aeruginosa and Pseudomonas cepacia from cystic fibrosis patients.

The in-vitro activities of ciprofloxacin, a new oxyquinoline derivative, norfloxacin and six anti-pseudomal beta-lactam antibiotics were tested against pulmonary isolates of smooth and mucoid colony forms of Pseudomonas aeruginosa, and Ps. cepacia from children with cystic fibrosis. Ciprofloxacin was the most effective of the agents tested against either species. Minimal inhibitory concentrations of ciprofloxacin were 0.5, and 16 mg/l, for 90% of the Ps. aeruginosa and Ps. cepacia strains tested, respectively. No effect of inoculum size or discordance between inhibitory or bactericidal concentrations was observed. Ciprofloxacin is a potentially useful agent for the treatment of acute pseudomonal pulmonary exacerbations in children with cystic fibrosis.

Anti-Bacterial Agents

Prevalence of myopia in school children in Vanuatu.

The onset of myopia typically occurs in childhood and increases during puberty. We studied the vision and refractive errors of 977 school children (ages 6 to 17 years) in 1983. Myopia in the group was extremely low; 97% had vision of 6/6, and 1.3% had myopia greater than 0.25D. Regression analysis revealed a change in mean refraction of -0.016D/year for males and -0.024D/year for females. There were no significant differences between males and females. These children engaged in about 8 hours of school work per day, and we conclude that genetic factors predominate over environmental factors in the determination of myopic refractive errors for this group.

Adolescent

Pharmacokinetics and cerebrospinal fluid penetration of ceftazidime in children with meningitis.

The single dose pharmacokinetics and cerebrospinal fluid (CSF) penetration of ceftazidime were determined in 10 children with bacterial meningitis. Serum ceftazidime pharmacokinetics showed a distinct age dependence in which the clearance in children less than 1 month of age was markedly reduced. Ceftazidime concentrations in CSF, which ranged from 1.4-8.5 micrograms/ml, exceeded the minimum bactericidal concentrations for infecting pathogens throughout the 8-hour sampling period. These concentrations were found to be independent of CSF cell count, protein concentration or the day of therapy on which the study was performed. The ratio of CSF to serum ceftazidime concentration increased with time, suggesting that ceftazidime was cleared more slowly from CSF than from peripheral blood. Our data support the initiation of a study comparing the efficacy of ceftazidime to conventional therapy in children with bacterial meningitis.

Age Factors

Pseudomonas cepacia colonization among patients with cystic fibrosis. A new opportunist.

Pseudomonas cepacia colonization among patients with cystic fibrosis (CF) at our center has increased from 7% (of 419 patients) to 15% (of 450 patients) over the past 5 yr (July 1978 through June 1983). The proportion of patients dying with P. cepacia colonization has increased over this 5-yr period (Year 1, 9% (1/11) of the deaths were associated with P. cepacia; Year 5, 55% (16/29) were associated with P. cepacia). These observations have led to a heightened concern regarding the presence of P. cepacia in the CF population. Characteristics of the patient population that might relate to P. cepacia colonization were reviewed. Increasing numbers of patients in good clinical condition became colonized with P. cepacia. Females in good clinical condition who acquire P. cepacia appear to be at special risk of developing severe and unexpected pulmonary complications that often end in death. In contrast, males, regardless of clinical condition, appear less likely to experience an immediate decline in clinical status. Hospitalization is potentially implicated in contributing to the increase in P. cepacia colonization because many patients' initial positive cultures were concurrent with or followed a hospital stay. Sixteen patients with CF and P. cepacia had siblings with CF, 6 of whom subsequently acquired P. cepacia. This frequency is more than double that in our overall CF population.

Adult