This article investigates the use of bedside abdominal ultrasonography (BAU) performed by emergency physicians (EPs) to screen patients for cholelithiasis and cholecystitis. In this prospective study EPs performed BAU on 116 patients. Agreement between BAU and formal abdominal ultrasound (FUS) performed in the radiology department for detecting cholelithiasis and cholecystitis was determined using Kappa statistics. Test characteristics of BAU for detecting cholelithiasis and acute cholecystitis were calculated. Agreement between BAU and FUS was 0.71 for cholelithiasis and 0.46 for acute cholecystitis. Test characteristics of BAU for cholelithiasis were sensitivity 92%, specificity 78%, positive predictive value (PPV) 86%, negative predictive value (NPV) 88%. Test characteristics of BAU for acute cholecystitis compared with clinical follow-up were sensitivity 91%, specificity 66%, PPV 70%, NPV 90%. BAU may be used to exclude cholelithiasis and is sensitive for cholecystitis. However, when EPs with limited experience identify cholecystitis a confirmatory test is warranted before cholecystectomy.

Acute Disease↗

PubMed2001

The prevalence and implications of incidental findings on ED abdominal CT scans.

We reviewed reports from 321 consecutive emergency department (ED) noncontrast, helical "renal stone" abdominal CT scans obtained at a single medical center between April 1996 to June 1997 for incidental findings. Incidental findings were common (45% of scans), and approximately half were rated of "moderate" or "serious" concern by 2 independent reviewers (kappa = 0.72). ED records indicated that only 21% of incidental findings were documented, and only 11 (18%) of cases with findings of "moderate/severe" concern had evidence of follow-up on hospital chart review. Although work-up of these 11 cases did not yield any serious diagnoses, many potentially serious incidental findings without follow-up remain worrisome.

Abdomen↗

PubMed2001

Evaluation of the Mastalex latex agglutination test for methicillin resistance in Staphylococcus aureus grown on different screening media.

The Mastalex MRSA latex agglutination method was evaluated with 52 methicillin-resistant and 27 methicillin-susceptible strains of Staphylococcus aureus grown on various media. All tests were correct with colonies grown on blood agar with or without oxacillin 2 mg/L. Tests on colonies grown on mannitol salt agar were less reliable, although addition of oxacillin 2 mg/L improved performance. One of the 26 MRSA which grew on Baird-Parker medium with 8 mg/L ciprofloxacin gave a false-negative result. Agglutination was faster when strains were grown on media with oxacillin. The method would be particularly useful for urgent confirmation of resistance.

Anti-Infective Agents↗

PubMed2001

External quality assessment of antimicrobial susceptibility testing in Europe.

Comparability of results of antimicrobial susceptibility testing is essential for resistance surveillance studies. As different methods may be used in different countries, there may be particular problems with international comparisons of resistance rates. Data from external quality assessment (EQA) surveys participated in by laboratories from several European countries allow comparison of performance between countries. In this study, success rates with organism-antimicrobial agent combinations known to be difficult to test were examined. With penicillin resistance in pneumococci; vancomycin and high-level gentamicin resistance in enterococci; ampicillin, co-amoxiclav and chloramphenicol resistance in Haemophilus influenzae and methicillin resistance in staphylococci there were differences between countries in success rates for discrimination of resistant strains. This study suggests that differences between countries in rates of resistance for some organism-antimicrobial agent combinations should be interpreted with caution. International EQA is useful in the demonstration and clarification of such differences.

Amoxicillin-Potassium Clavulanate Combination↗

PubMed2001

Detection of beta-lactamase-mediated resistance.

beta-Lactams are the most widely used antibiotics, and beta-lactamases are the greatest source of resistance to them. An understanding of beta-lactamase detection and identification is therefore valuable. Colorimetric, acidimetric and iodometric tests of beta-lactamase production are good, rapid indicators of penicillin and ampicillin resistance in Haemophilus, Moraxella and Neisseria spp. These methods can also be applied to Gram-negative aerobic bacilli but are less useful, since the usual question is not whether a beta-lactamase is produced by these organisms, but which beta-lactamase? Accurate identification of the beta-lactamases of Enterobacteriaceae demands gene or protein sequencing, but the broad type of enzyme produced by an isolate can often be inferred from antibiotic susceptibility data. Resistance to ceftazidime or cefpodoxime implies extended-spectrum beta-lactamase (ESBL) production in Escherichia coli and Klebsiella spp., especially if susceptibility to cefoxitin is retained. ESBL production can be confirmed with double disc tests or with various commercial kits. Derepression of AmpC beta-lactamases in Enterobacter spp. and Citrobacter freundii is another important mechanism and can be inferred from cross-resistance to beta-lactamase inhibitor combinations and to all cephalosporins except fourth-generation agents. Antagonism between cefoxitin and cefotaxime can be used to infer the presence of inducible AmpC enzymes in these species, indicating the risk of segregation of derepressed mutants, but in general this risk is better predicted from accurate speciation.

Bacteria↗

PubMed2001

Detection of methicillin/oxacillin resistance in staphylococci.

Methicillin/oxacillin-resistant staphylococci are heterogeneous in their expression of resistance to beta-lactam agents and the test conditions have a major effect on the expression and therefore the detection of resistance. Conflicting recommendations regarding the most reliable method for routine use are partly related to differences between strains and there may be a variable interaction between the factors affecting the expression of resistance, including the agent tested, the medium, the NaCl concentration, the inoculum, temperature and period of incubation and the reading of endpoints. 'Borderline' resistant strains may have altered PBPs or be penicillinase hyperproducers, and these can be difficult to distinguish from resistant strains that carry the mecA gene. Recommended methods for MIC and disc diffusion testing are described, although it is unlikely that any single method will detect all resistant strains. Some rapid and/or automated methods are also available, including latex agglutination techniques for the detection of PBP2a. The gold standard method for the detection of resistance mediated by mecA is PCR, which is most commonly used as a reference method at present.

Bacterial Proteins↗

PubMed2001

Quality assurance of antimicrobial susceptibility testing by disc diffusion.

Quality assurance is essential to ensure the quality of antimicrobial susceptibility tests by diffusion methods. Routine internal quality control testing with a range of control strains is a major part of the quality assurance process, as it facilitates monitoring of the performance of the test. Most standardized methods include tables of acceptable zone size ranges for control strains and, in addition to checking that control zone diameters are within the published ranges, rules or statistical approaches may be applied to indicate deviations from acceptable performance. If control tests indicate unacceptable performance, the source(s) of the error should be investigated and may include problems with media, antimicrobial discs, inoculum and plate reading. Participation in external quality assessment schemes provides an independent assessment of performance although the number of strains distributed in such schemes is limited. Internal quality assessment in which routine tests are repeated with the identity of the organisms blinded is a useful complementary approach to external quality assessment and may detect problem areas not highlighted by other control methods. Education is an important part of the quality assurance process. Knowledge of atypical results for different organism-agent combinations may provide warning of possibly erroneous results, and an understanding of the limitations and sources of error in disc diffusion methods contributes significantly to the recognition, resolution and avoidance of errors.

Anti-Bacterial Agents↗

PubMed2001

Instrumentation in antimicrobial susceptibility testing.

Studies in the 1960s demonstrated the problems of variability in susceptibility testing methods, especially those affecting the performance of disc diffusion procedures. These studies made apparent the need for standardization and resulted in more clearly defined performance limits for growth medium, incubation conditions, inoculum concentration, disc content for diffusion methods, the setting of interpretative MIC breakpoints and the establishment of quality control parameters. More recently, there has been a growing interest in the use of instrumentation for reading disc diffusion tests and the endpoints of agar or broth dilution MIC determinations. Instrumentation ranges in complexity from the simple optical reading of zones of inhibition or growth endpoints, requiring operator interpretation, to more sophisticated devices for reading, recording and 'expert system' analysis of results with interfacing of instruments to laboratory information management systems. Some of the more developed systems are fully automated and can also identify the organisms tested. The pressure to reduce labour costs and provide results earlier favours the use of more automated systems whilst the requirement for resistance surveillance provides impetus for the use of systems that provide quantitative results and electronic data handling.

Bacteria↗

PubMed2001

Rapid screening technique for class 1 integrons in Enterobacteriaceae and nonfermenting gram-negative bacteria and its use in molecular epidemiology.

A screening technique for integrons in members of the family Enterobacteriaceae and nonfermenting gram-negative bacteria by real-time PCR is reported. A total of 226 isolates of gram-negative bacteria obtained from a variety of clinical specimens were screened for class 1 integrons by real-time PCR performed on a LightCycler instrument. This technique used a primer pair specific for a 300-bp conserved region at the 5' ends of class 1 integrons. The screening assay was evaluated by comparison with results obtained by the conventional, thermal-block PCR (long PCR) by using established conditions and primers for the detection of class 1 integrons, and the real-time PCR technique was thus shown to be both sensitive and specific. DNA from 50 of 226 (22%) isolates screened was identified as containing an integron by the screening PCR, and sequence data were obtained across the integron for 34 of 50 (68%) of these isolates. In an attempt to study the molecular epidemiology of antimicrobial resistance genes carried within integrons, a comparison of the types of gene cassettes carried by isolates from different patients was made. Adenyltransferase genes conferring resistance to streptomycin and spectinomycin were the predominant gene cassettes amplified in the study. Resistance to trimethoprim was also frequently found to be encoded within integrons. Furthermore, multiple bacterial isolates obtained from one patient over a 5-month period were all shown to carry an integron containing the same single adenyltransferase gene cassette, suggesting that these elements were relatively stable in this case.

Community-Acquired Infections↗

PubMed2000

Cough and shortness of breath.

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Abdominal Pain↗

PubMed2000

Syncope in pregnancy.

Explore the source record for details and available documents.

Adult↗