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Biomedical subjects

A C Hamoudi

Publications and source records attributed to A C Hamoudi.

At least 19 recordsLinked to original sources
PubMed1994

Quality improvement approaches. Survey of pathologists serving the pediatric patient.

A questionnaire was circulated in 1990 by the Practice Committee of the Society for Pediatric Pathology to its membership to assess the involvement of pediatric pathology departments (PPDs) in quality improvement (QI) activities. Twenty-nine PPDs responded. Analysis of responses disclosed a wide variation in plans, although the majority (22 of 29) had developed or were in the process of developing (three of 29) a specific plan. The plans varied in sophistication and complexity. Pediatric pathologists (directors or designates) were heavily involved in assuming leadership roles for the QI activities in 25 of 28 PPDs. The PPDs with plans (25) had identified the QI indicators monitored either sporadically or on an ongoing basis. The respondents had several indicators in common, such as volume, technical, and clinical indicators, as well as indicators related to turnaround times, meetings, and internal and external consultations. The plurality of the monitors reported are related to indicators in the discipline of anatomic pathology. This review is therefore limited to QI issues in anatomic pediatric pathology. In conclusion, this survey functions to shed some light on the extent of involvement of PPDs in the management of QI. In addition, it provides a model for starting or improving the existing QI plans for PPDs.

Autopsy↗
PubMed1993

Intravascular calcium deposits in a critically ill patient. Light- and electron-microscopic findings.

We describe a case of a 2-year-old girl with an unusual finding of amorphous hematoxyphilic substance in the pulmonary and myocardial vascular lumina. The patient had a prolonged history of intestinal obstruction necessitating extended periods of total parenteral nutrition. The patient terminally had hypercalcemia with levels reaching 4.63 mmol/L. The intravascular substance stains strongly positive for calcium, and weakly positive for fibrin. Electron microscopy shows that the substance has a distinctive configuration suggestive of calcium hydroxyapatite crystals.

Blood Vessels↗
PubMed1991

The use of LIS for blood usage review. Experience in a children's hospital.

To comply with the requirements of the Joint Commission for the Accreditation of Healthcare Organizations (JCAHO) and to facilitate the review process, the authors designed a program to screen for the appropriateness of packed red cell (PRC) and platelet concentrate (PLT) transfusions. The purpose of this report is to describe the methodology of the review process. A quality assurance (QA) monitor was created in the Laboratory Information System (LIS) to screen indicators: hemoglobin for PRCs and platelet count for PLTs. Numerical value limits were defined to determine acceptable ranges. Each week, the LIS compiles a list of all patients who received transfusions and for whom the QA monitor determined that the values of the screened indicators were outside the defined appropriate limits. A detailed transfusion record is generated for each patient identified. During a six-month evaluation of this program, a total of 1,788 PRC and 3,109 PLT units were transfused. Of these, 582 PRC (32.5%) and 2,219 PLT (71.4%) units were within the acceptable guidelines. Lists for the remaining 1,206 PRCs and 890 PLTs were generated. Review of the transfusion record and other laboratory values from the LIS established the appropriateness of 1,052 PRC and 782 PLT transfusions. At the conclusion of the six-month period, the medical charts for 181 (11%) PRC and 108 (4.5%) PLT transfusions required chart review. This method provided major reduction in time of the transfusion review process. Similar guidelines may be used to monitor other transfusion products such as fresh frozen plasma.

Blood Transfusion↗
PubMed1990

Clinical relevance of viridans and nonhemolytic streptococci isolated from blood and cerebrospinal fluid in a pediatric population.

Laboratory records were reviewed to assess the clinical relevance of isolating viridans (VS) and nonhemolytic (NHS) streptococci from blood and cerebrospinal fluid (CSF) specimens in a pediatric setting. During a nine-month period, 722 of 6,569 blood cultures and 113 of 2,023 CSF cultures were positive for one or more organisms. There were 26 VS and 10 NHS blood isolates from 30 patients and five NHS isolates from the CSF of five additional patients. The patients ranged in age from five weeks to 16 years. The charts of 34 patients were reviewed for evidence of sepsis or meningitis and the physician's response to the positive cultures. Three patients had subacute bacterial endocarditis (SBE) with multiple positive blood cultures. All other patients, including six oncology patients, failed to show a positive correlation between the isolation of VS or NHS and the disease process. Speciation and MIC testing were performed on 13 isolates, including those from all SBE and four oncology patients. Because of the lack of significance of VS and NHS from blood and CSF specimens in patients other than those with SBE, the authors conclude that extensive microbiologic workup of VS and NHS is not necessary without appropriate clinical indications such as SBE or immunosuppression.

Adolescent↗
PubMed1988

Evaluation of a direct identification method for Staphylococcus aureus from blood culture broth.

We evaluated the reliability of Staphaurex (Wellcome Diagnostics, Dartford, England) for the direct identification of staphylococci from blood culture broth with evidence of positivity and a suggestive Gram-stained smear. Our evaluation indicates that this application is of limited sensitivity, thus reducing the value of a negative test. However, since the test is highly specific, a positive test is significant in predicting the isolation of Staphylococcus aureus.

Blood↗
PubMed1988

Occurrence of mucoid M-18 Streptococcus pyogenes in a central Ohio pediatric population.

During a 1-year period from October 1986 through September 1987, we recovered 116 mucoid, hemolytic Streptococcus pyogenes isolates from clinical specimens collected from patients seen at our pediatric institution. A total of 102 isolates were from throat cultures (101 for pharyngitis, 1 for acute rheumatic fever), 13 were from other superficial body sites, and 1 was from pleural fluid. All of 40 mucoid isolates tested to date were determined to be M-type 18 strains. A direct latex agglutination test for group A carbohydrate antigen in throat swab specimens was equally sensitive in detecting M-18 mucoid and nonmucoid strains (45 of 77 [58%] and 795 of 1,186 [67%], respectively; not significant, P greater than 0.05). Antimicrobial susceptibility tests performed with 40 mucoid and 40 nonmucoid isolates against penicillin and nine other antimicrobial agents showed all strains to be susceptible, with no difference in MICs. All isolates tested were also considered fully susceptible to the bactericidal activity of penicillin. Further studies are needed to establish the relative virulence of M-18 strains and their possible association with the resurgence of acute rheumatic fever in central Ohio and other areas of the United States.

Anti-Bacterial Agents↗
PubMed1988

Do regional variations in prevalence of cryptosporidiosis occur? The central Ohio experience.

We screened 2,780 consecutive stool specimens submitted for routine ova and parasite examination to assess the prevalence of cryptosporidiosis in a pediatric patient population in central Ohio. The stools were prepared by formalin-ethyl acetate concentration followed by cold Kinyoun acid-fast stain of the sediment. In addition, 912 consecutive intestinal biopsies were monitored for the presence of the parasite. Cryptosporidium oocysts were found in only 0.3 per cent of stool specimens (seven specimens from three patients) and in none of the intestinal biopsies. Due to this low prevalence of cryptosporidiosis, we conclude that routine screening of stool specimens for Cryptosporidium sp. is unnecessary in our patient population. Screening should be targeted to immune compromised patients and patients with persistent diarrhea and no apparent etiology. Our study also supports the concept that there are geographic variations in the prevalence of cryptosporidiosis.

Child↗
PubMed1987

Comparison of throat and nasopharyngeal swab specimens for culture diagnosis of Bordetella pertussis infection.

During a 9-month period, we evaluated the relative sensitivity of throat and nasopharyngeal swab cultures for isolation of Bordetella pertussis. Of 38 pertussis cases, 36 (95%) had positive nasopharyngeal cultures, while only 16 of 36 (44%) had positive throat cultures. There were no cases of nasopharyngeal-negative, throat-positive cultures. The sensitivity of the direct fluorescent-antibody test was 70% when compared with culture.

Bordetella pertussis↗
PubMed1986

Rapid screening and microbiologic processing of pediatric urine specimens.

Urinary nitrite and leukocyte esterase dipstick tests were evaluated as rapid screening procedures to select probable culture-positive urines for direct identification (AutoMicrobic System urine cards) and modified Kirby-Bauer susceptibility testing. Approximately 73% of significant culture-positive (greater than 10(5) organisms per milliliter, pure culture) urine specimens could be selected by nitrite testing alone with very high specificity (approximately 99%). The leukocyte esterase test detected 85% of culture-positive urines when used alone and approximately 91% when used in combination with nitrite testing (if either test was positive it was considered a positive screening); however, the esterase test was significantly less specific for bacteriuria than the nitrite test. Based on these results, the nitrite test was selected for use as the screening test. Rapid, direct identification and susceptibility tests on screen-positive urines showed 97% correlation with standard testing methods. Significant positive urines processed in this manner could be reported with quantitation, identification, and susceptibility results within 24 hr.

Anti-Bacterial Agents↗
PubMed1986

Can the cost savings of eliminating urine microscopy in biochemically negative urines be extended to the pediatric population?

The authors determined the value of performing urine microscopy on biochemically negative urine specimens in a pediatric population. Four reactions of the Chemstrip-9TM (Biodynamics, Inc., Indianapolis, IN) were used as biochemical indicators, namely, protein, occult blood, leukocyte esterase, and nitrite. Out of 1,016 urine specimens thus studied, 310 were true positive. Eleven specimens reacted biochemically in the absence of significant microscopic findings (false positive), 668 specimens were negative by the Chemstrip-9 and were either negative microscopically or had less than five white blood cells (WBCs) per high power field (HPF) and were considered true negatives. Twenty-seven specimens had negative biochemical indicators, in spite of positive microscopy; of these specimens, only seven had more than ten WBCs per HPF, 17 had five to ten WBCs per HPF, and three had five to ten red blood cells per HPF. The sensitivity of the four parameters for predicting significant microscopy of urinary sediment is 91% and the specificity is 98%. The predictive value of a negative result is 96.1%, and that of a positive result is 96.5%. The authors therefore conclude that urine microscopy is unnecessary in biochemically negative urine specimens from pediatric patients who are asymptomatic for urinary tract disease.

Child↗
PubMed1984

Comparative laboratory evaluation of three antigen detection methods for diagnosis of Haemophilus influenzae type b disease.

Cerebrospinal fluid, urine, serum, and other body fluid specimens from pediatric patients with systemic disease were tested with Bactigen latex agglutination (555 specimens), Phadebact coagglutination (319 specimens), and counterimmunoelectrophoresis (335 specimens) for the presence of Haemophilus influenzae type b antigen. All three methods showed good sensitivity for detecting antigen in the cerebrospinal fluid of patients with culture-positive meningitis (greater than or equal to 86% sensitivity). However, coagglutination and counterimmunoelectrophoresis were much less sensitive (less than or equal to 40%) than latex agglutination (96%) for detecting antigen in other body fluid specimens in culture-positive, nonmeningeal H. influenzae disease. Bactigen latex agglutination was also more sensitive than the other procedures for detecting antigen in specimens from patients with culture-negative, presumed H. influenzae disease. Comparative testing of fluids spiked with known quantities of purified H. influenzae b polyribosephosphate capsular polysaccharide revealed an apparent 100-fold greater sensitivity with Bactigen as compared with the other two methods. Although all three methods showed good specificity (greater than 98%), both agglutination methods gave a few false-positive results. In a clinical setting where both meningeal and nonmeningeal H. influenzae b disease are encountered frequently, Bactigen latex agglutination appears to be superior to coagglutination and counterimmunoelectrophoresis for detecting antigen in body fluids.

Agglutination Tests↗
PubMed1984

Evaluation of rapid identification of gram-positive cocci in positive blood cultures by use of the AutoMicrobic system Gram-Positive Identification Card.

Because rapid identification of gram-positive organisms from blood cultures may provide valuable information for patient care and because the AutoMicrobic system Gram-Positive Identification (AMS-GPI) Card (Vitek Systems, Inc., Hazelwood, Mo.) is designed for the identification of these organisms in 4 to 13 h, we designed this study to evaluate the performance of the AMS-GPI Card in the direct identification of gram-positive organisms upon detection of growth in blood culture bottles. We compared direct identification by the AMS-GPI Card with the final AMS-GPI Card identification and with our standard identification methods. We evaluated 51 gram-positive organisms from clinical blood cultures as well as 49 simulated blood cultures. The isolates included Streptococcus pneumoniae (17), Streptococcus pyogenes (13), group D enterococci (12), Streptococcus agalactiae (11), viridans streptococci (10), coagulase-negative staphylococci (21), Staphylococcus aureus (15), and Listeria monocytogenes (1). The AMS-GPI Card identified all of the group D enterococci, viridans streptococci, and coagulase-negative staphylococci and all but one each of the Streptococcus pyogenes and Streptococcus agalactiae isolates. L. monocytogenes was also correctly identified. However, the AMS-GPI Card identified only 12 of 17 Streptococcus pneumoniae and 9 of 15 Staphylococcus aureus isolates by direct inoculation. We therefore conclude that the results of direct identification of gram-positive organisms by the AMS-GPI Card may be used cautiously for rapid direct identification of gram-positive organisms from positive blood cultures.

Bacteriological Techniques↗
PubMed1982

Rapid diagnostic techniques for bacterial meningitis.

The purpose of this review is to provide an overview of the most prevalent current methods for rapid diagnosis of meningitis. In addition, some of those techniques which, while not yet practicable for most laboratories but are on the clinical horizon, have been surveyed. Two principles which emerge from this review are that many of the older techniques, such as Gram stain, retain their clinical utility by virtue of their practicality, cost-benefit ratio, and simplicity; and many of the more sophisticated techniques which are now emerging from the research arena (such as FPEC-GLC), facilitate rapid diagnosis where it has not previously existed. Also, when identification of the infectious agent depends on antigen detection, prior treatment will not compromise the results. Therefore, the combination of old and new laboratory methods for diagnosing meningitis provides a much wider, more effective and efficient set of diagnostic tools than was previously available.

Antigens, Bacterial↗
PubMed1981

Fatal group B streptococcal pneumonia in neonates. Effects of antibiotics.

Prophylactic penicillin has been suggested to prevent neonatal group B streptococcal infections (GBS). However, there is a concern that the antibiotics may conceal significant bacteremia if post-treatment blood cultures were used to recover the etiologic agent. To clarify this point, the autopsy records of 111 cases of fatal neonatal pneumonias is infants less than one week of age for the period 1974-1978 were reviewed. Nineteen documented cases of group B streptococcal infections were uncovered. Review of antibiotic therapy in these infants indicate that such therapy can indeed conceal the etiologic agent of pneumonia if one uses post treatment blood (or other normally sterile body fluids) cultures as the basis of diagnosis. On the other hand, review of 41 cases with morphologic evidence of pneumonia and no identifiable etiologic agent reveal that the majority of these were referral cases from outlying hospitals who received antibiotics prior to any diagnostic work-up.

Anti-Bacterial Agents↗
PubMed1981

Cost analysis of the Auto Microbic system urine identification card.

The AutoMicrobic system (Vitek Systems, Inc., Hazelwood, Mo.) is a fully automated, computerized instrument. One of the most thoroughly studied aspects of the system is its ability to identify and quantify of nine most common urinary tract pathogens. The major advantages of the AutoMicrobic system are that the results of urine cultures are available in a fraction of the time required by conventional methods and that samples can be processed with fewer man-hours. Although the specificity, sensitivity, and reliability of the system have been amply described in the literature, only one study combines these aspects with a cost analysis (D. P. Nicholson and J. A. Koepke, J. Clin. Microbiol. 10:823-833, 1979). Because one of the major considerations that microbiology laboratory directors must face is the cost-effectiveness of instruments, we studied the relative cost of the system as compared with that of conventional methods. Our findings indicated that the instrument provided valuable savings in technologist and turnaround time. These advantages were most easily realized in processing positive urine specimens. For negative urine specimens, the savings in technologist time were cancelled by the cost of the consumable supplies, which greatly exceeded the cost of supplies for conventional methods. This disadvantage might be ameliorated by efficient and effective screening methods to exclude those urine specimens that are most probably negative.

Autoanalysis↗