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Biomedical subjects

J W Warren

Publications and source records attributed to J W Warren.

At least 109 records · Page 6Linked to original sources
PubMed1986

Do clinical microbiology laboratories report complete bacteriology in urine from patients with long-term urinary catheters?

Bacteriuria associated with long-term urinary catheters (those in place for greater than or equal to 30 days) appears to be the most common nosocomial infection in U.S. medical care facilities. This bacteriuria is polymicrobial and dynamic and accompanied by fevers, catheter obstructions, bacteremias, and deaths. We compared the reporting by our research laboratory of bacteria present in urine from long-term-catheterized nursing home patients with that by two commercial laboratories. The commercial laboratories isolated significantly fewer bacterial species at 10(5) CFU/ml of urine specimen. Organisms well recognized as causes of urinary tract infections in noncatheterized patients (Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae) were isolated in comparable frequencies by both the research and commercial laboratories. However, other organisms, including uncommon uropathogens like Providencia stuartii and Morganella morganii, which were actually among the most frequent bacteriuric species in these long-term-catheterized patients, were isolated significantly less frequently by the commercial laboratories. Reasons for the discrepancies are unclear but may involve use of different techniques. More complete reporting may lead to better understanding of the polymicrobial bacteriuria of long-term catheters and its associated complications. This, in turn, may result in improved patient care and infection control in nursing homes.

Aged↗
PubMed1986

A randomized controlled trial of moxalactam versus clindamycin/tobramycin in the treatment of mixed anaerobic/aerobic infections.

Many infections are due to mixtures of facultative gram-negative bacilli and anaerobic bacteria. Moxalactam, a semisynthetic beta lactam antibiotic, is active against a wide range of anaerobic organisms, including most strains of Bacteroides fragilis, as well as many aerobic gram-negative bacilli. We performed a prospective, randomized controlled trial comparing moxalactam alone with the regimen of clindamycin and tobramycin for treatment of mixed aerobic/anaerobic infections. One hundred and six patients with presumed mixed infections were randomized to the study groups. The resultant groups were clinically and microbiologically comparable. The effectiveness of treatment was similar with both antibiotic regimens. Five of 25 patients tested in the moxalactam group had a prolongation of their prothrombin time and one of them developed clinically important bleeding. Two of the 23 patients tested in the clindamycin/tobramycin group had a prolonged prothrombin time with no bleeding. Decreases in hematocrit which could be "probably" or "possibly" related to antimicrobial use were seen in 6 of 48 moxalactam patients and none of 50 clindamycin/tobramycin patients (P = .03). Moxalactam, a potent antimicrobial for both anaerobic and aerobic organisms, demonstrated effectiveness in treating mixed anaerobic/aerobic infections similar to clindamycin/tobramycin but was associated with clinically important decreases in hematocrit.

Bacterial Infections↗
PubMed1986

Catheters and catheter care.

For patients with incontinence who cannot be managed by other means, external or internal urine collecting devices may be useful. Condom catheters have been used for men, but analogous external collection devices for women are not widely available. Long-term urethral catheterization causes a dynamic polymicrobial bacteriuria that may be complicated by fever, catheter obstruction, bacteremia, acute pyelonephritis, urinary stones, chronic tubulointerstitial nephritis, renal failure, or death. Understanding these complications may lead to better decisions for patients and perhaps to new management options for incontinence.

Aged↗
PubMed1985

Effective extraction of diagnostic ECG waveform information using orthonormal basis functions derived from body surface potential maps.

A common basis of orthogonal waveform functions was derived from 128 lead body surface potential maps of 405 subjects. Twelve such orthogonal functions or frames were adequate for reconstruction of original ECGs from the beginning of QRS to the end of T. A larger number of frames (18) was required when basis functions were derived separately for QRS (10) and ST-T segments (8). Diagnostic information content of the coefficients of the orthogonal basis functions was evaluated in comparison with Minnesota Code criteria for myocardial infarction and with a more advanced multivariate ECG analysis program (Pipberger Program). This was done by deriving a linear discriminant function for separating normals from ECGs of patients with myocardial infarction and testing the discriminant in a different test population of infarcts and normals. The diagnostic accuracy of orthogonal basis functions was as good as that of Pipberger's program and considerably better than that of the Minnesota Code. The classification method described is insensitive to noise and errors in detecting QRS and T wave onsets and offsets or in selecting proper baseline for amplitude measurements. The robustness and enhanced classification stability with respect to noise and minor wave detection errors is a potential advantage particularly in serial ECG comparison.

Adult↗
PubMed1985

Variable phenotypes of Providencia stuartii due to plasmid-encoded traits.

Weekly urine specimens from 51 long-term catheterized patients yielded 699 isolates of Providencia stuartii. Urease-positive strains represented 23.7% (166) of the isolates, sucrose-positive strains represented 24.5% (171), and lactose-utilizing strains represented 0.7% (5). Urease and sucrose traits were transferred by conjugation to Escherichia coli via an 82-kilobase plasmid; lactose fermentation was transferred by a 150-kilobase plasmid.

Bacteriuria↗
PubMed1984

Liquid chromatographic analysis of dichlorophen and its major impurity.

A rapid and simple high-performance liquid chromatographic (HPLC) method for the analysis of dichlorophen in raw material and in dichlorophen-toluene soft gelatin capsules for veterinary use was developed using a reverse-phase technique. This HPLC system was shown to isolate dichlorophen from its major impurity (the trimer). Three formulations were assayed and were found to contain 7.14, 7.90, and 8.4% of the trimer. A C-18 column was used with a mobile phase of methanol-water (75:25). The flow rate was 1.5 mL/min, and the effluent was monitored at 290 nm for both dichlorophen and the trimer. Dichlorophen and the trimer had retention times of 6.5 and 9.0 min, respectively.

Capsules↗
PubMed1984

Lack of interference with creatinine assays by four cephalosporin-like antibiotics.

Some cephalosporin-like antibiotics have been shown to interfere with creatinine assays performed by the commonly used Jaffe methods. The authors show that four new drugs of this type--moxalactam, cefoperazone, cefotaxime, and ceftazidime--do not interfere with this test. A table is presented summarizing all literature data regarding interference with creatinine assays of cephalosporin-like drugs.

Cefoperazone↗
PubMed1983

Bactericidal activity of norfloxacin and nine other urinary tract antibiotics against Gram-negative bacilli causing bacteriuria in chronically catheterized patients.

We compared the bactericidal activities of norfloxacin and nine other oral urinary tract antibiotics against 344 Gram-negative bacilli causing bacteriuria in chronically catheterized patients. Norfloxacin killed all organisms at 32 mg/l, 91% of isolates at 2 mg/l, and was the most active antibiotic tested.

Anti-Infective Agents, Urinary↗
PubMed1983

Imipenem therapy of Pseudomonas aeruginosa bacteraemia in neutropenic rats.

Rats were made neutropenic by intraperitoneal (ip) injection of cyclophosphamide. Those neutropenic (mean white blood cell count of 470/mm3) rats were challenged intraperitoneally with Pseudomonas aeruginosa to assess the efficacy of single agent therapy with either imipenem, latamoxef (moxalactam) or amikacin, or combination therapy with imipenem-amikacin or latamoxef (moxalactam)--amikacin. Pharmacokinetic studies were performed in rats to assure that therapy was equivalent during therapeutic trials. Three levels of bacterial challenge (4 LD50, 13 LD50 and 250 LD50) were examined. At all challenge levels, single agent therapy with latamoxef (moxalactam) failed to significantly protect rats from fatal bacteraemia. Single-agent therapy with amikacin did significantly protect rats from fatal bacteraemia at the lower challenge levels, but not at the 250 LD50 challenge. Single agent therapy with imipenem significantly protected rats at all challenge. Single agent therapy with imipenem significantly protected rats at all challenge levels. In-vitro studies established a synergistic effect when combination antibiotics were used. This correlated with in-vivo findings that combination therapy resulted in improved rat survival and recovery of fewer Ps. aeruginosa isolates. The latamoxef (moxalactam)-amikacin combination was more effective than either agent alone, but was not more effective than imipenem alone. The imipenem-amikacin combination was the most effective therapeutic regimen tested. These results suggest that imipenem alone, and particularly when combined with an aminoglycoside, is effective in treating serious Ps. aeruginosa infections in neutropenic rats. Clinical studies in infected immunocompromised patients may be warranted.

Agranulocytosis↗
PubMed1983

Ineffectiveness of cephalexin in treatment of cephalexin-resistant bacteriuria in patients with chronic indwelling urethral catheters.

Catheterized patients not only are subject to risks of bacteriuria but the catheter also may act as reservoirs for nosocomial infections. Antibiotics that are concentrated in the urine, even those to which the organisms are nominally resistant, have been advocated as a means of treatment and infection control. During a randomized study of repetitive 10-day courses of cephalexin in chronically catheterized patients we observed the impact of such treatment upon susceptible, moderately resistant and highly resistant strains of bacteria. Cephalexin diminished the persistence of cephalexin-susceptible strains. However, its effect upon moderately resistant (inhibited by 200 micrograms per ml.) was not different than its effect upon highly resistant (not inhibited by 200 micrograms per ml.) strains. Indeed, the persistence of strains of moderately and highly resistant organisms during cephalexin courses was similar to that of such organisms during comparable periods in patients not receiving cephalexin. The administration of cephalexin to chronically catheterized patients with moderately or highly resistant organisms causing bacteriuria does not clear these organisms from the urine.

Adult↗
PubMed1982

Cephalexin for susceptible bacteriuria in afebrile, long-term catheterized patients.

Patients with long-term indwelling urethral catheters are subject to acute and long-term complications of bacteriuria. To evaluate the common practice of short-course antibiotic therapy in such patients, we performed a randomized controlled trial of ten-day courses of cephalexin monohydrate repeated whenever a susceptible bacteriuria was present. We observed 17 cephalexin group patients for 545 patient-weeks (160 cephalexin courses) and 18 control group patients for 477 patient-weeks. Throughout the study, the groups were comparable in regard to incidence and prevalence of bacteriuria, number of bacterial strains per weekly urine specimen, incidence of febrile days, and incidence of obstructed catheters. In the cephalexin group, the frequency of fever during periods when antibiotics were being used was similar to that during periods when antibiotics were not being used. More cephalexin-resistant bacteria were isolated from cephalexin group patients. Routine treatment with cephalexin of asymptomatic long-term catheterized patients, even for susceptible organisms, does not seem to be warranted.

Adult↗
PubMed1982

A prospective microbiologic study of bacteriuria in patients with chronic indwelling urethral catheters.

Bacteriuria is common in chronically catheterized patients and is associated with both acute and chronic complications. Of 605 consecutive weekly urine specimens from 20 chronically catheterized patients, 98% contained bacteria at high concentrations and 77% were polymicrobial. The mean interval between new episodes of bacteriuria was 1.8 weeks. Most species of bacteria caused five to seven new episodes of bacteriuria per 100 weeks of catheterization. Even though access to the catheter lumen was similar, the duration of bacteriuric episodes varied greatly by species. Of the episodes of bacteriuria caused by nonenterococcal gram-positive cocci, greater than 75% lasted less than one week. Mean durations of episodes of bacteriuria due to Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa were four to six weeks, whereas those due to Providencia stuartii averaged 10 weeks and ranged up to 36 weeks. Thus, the very high prevalence of bacteriuria--virtually 100%--was a result of a high incidence caused by many different species combined with the prolonged residence of some gram-negative bacilli in the catheter and urinary tract.

Adult↗
PubMed1982

A prospective randomized controlled trial of cefoxitin versus clindamycin-aminoglycoside in mixed anaerobic-aerobic infections.

Ninety patients infected with presumed penicillin resistant anaerobes were randomized to cefoxitin or clindamycin-aminoglycoside. Cefoxitin was comparable to clindamycin-aminoglycoside in cures of intestinal associated, 16 of 26 versus 11 of 21, and pelvic infections, 20 of 20 versus 22 of 23. Cefoxitin-resistant facultative-aerobic gram-negative rods were found in 16 of 45 patients with intestine associated infection. Probable antibiotic associated nephrotoxicity was less frequent in the patients in the cefoxitin group, zero of 46 versus seven of 44, p less than 0.05, although a false creatinine elevation was noted more frequent, seven of 46 versus one of 44, p less than 0.05. Infections causing failure in patients in the cefoxitin group more frequently contained cefoxitin resistant gram-negative rods at the time of failure than did infections causing failure in those in the clindamycin-aminoglycoside group that contained gentamicin-resistant gram-negative rods, eight of eight versus zero of eight, p less than 0.001. Cefoxitin may be adequate therapy for many patients with mixed anaerobic/aerobic infections; however, the addition of an aminoglycoside may be prudent in those with known, or suspected, cefoxitin resistant gram-negative rods.

Adolescent↗
PubMed1981

Cardiac infarction injury score: an electrocardiographic coding scheme for ischemic heart disease.

A multivariate decision-theoretic electrocardiogram (ECG) classification scheme called Cardiac Infarction Injury Score (CIIS) was developed using ECGs of 387 patients with myocardial infarction (MI) and 320 subjects without infarction. The most accurate and stable classification was achieved by using a combination of eight binary (single threshold), three ternary (two thresholds), and four ECG features measured on a continuous scale. For practical visual coding of ECGs, the CIIS coding procedure uses a checklist containing 12 items measured from the conventional 12-lead ECG. The CIIS test results indicate that, in comparison with conventional ECG criteria for MI used in clinical trials, the diagnostic accuracy can be considerably improved by optimizing feature and threshold selection and by multivariate analysis. The CIIS detected MI with a sensitivity of 85% and a specificity of 95%. Using a higher severity level, a specificity of 99% was achieved, with a sensitivity of 71%. One of the primary uses of the CIIS is coding of significant worsening of the ECG with new coronary events from annually recorded ECGs in clinical trials and epidemiologic studies.

Adult↗
PubMed1980

Infection with Mycoplasma hominis in postpartum fever.

A follow-up of 535 patients after vaginal delivery showed that 9% had a fever of 37.7 degrees C or greater, and 2% had a fever of 38 degrees C or more, on two days. The commonest cause of both categories of fever was Mycoplasma hominis infection as defined by a fourfold or greater rise in mycoplasmacidal antibody titre. Among women for whom sera were available this agent caused 50% (14/28) of all fevers and 71% (5/7) of the higher fevers. Absence or low titre (< 1:8) of antibody against M. hominis was the strongest single predictor of otherwise unexplained fever (16/40 patients with low antibody titre were febrile vs 7/50 with high antibody titre, p < 0.01). Among women with absent or low antibody titres, both rise in titre of antibody to this organism and lochial colonisation by it were significantly associated with fever (p < 0.001, p < 0.025, respectively). Standard microbiological and clinical techniques identified probable causes in only 18% (5/28) of all fevers and 29% (2/7) of higher fevers. Patients who had postpartum infection caused by M. hominis remained in hospital 31% longer than the non-infected patients (4.57 vs 3.49 days, p < 0.001). Low antibody to and lochial colonisation with M. hominis occurred together in 17% of patients, who accounted for 71% of all higher fevers. Since these risk factors for postpartum fever can be identified before delivery, prophylactic measures applied selectively to women with these risk factors may prevent a large proportion of postpartum fevers and the excess hospital stay associated with them.

Adult↗