2012 March

Should registrars be reporting after-hours CT scans? A calculation of error rate and the influencing factors in South Africa.

Mar 312012

Should registrars be reporting after-hours CT scans? A calculation of error rate and the influencing factors in South Africa.

Acta Radiol. 2012 Feb 1;53(1):61-8

Authors: Terreblanche OD, Andronikou S, Hlabangana LT, Brown T, Boshoff PE

Abstract
BACKGROUND: There is a heavy reliance on registrars for after-hours CT reporting with a resultant unavoidable error rate.
PURPOSE: To determine the after-hours CT reporting error rate by radiology registrars and influencing factors on this error rate.
MATERIAL AND METHODS: A 2-month prospective study was undertaken at two tertiary, level 1 trauma centers in Johannesburg, South Africa. Provisional CT reports issued by the registrar on call were reviewed by a qualified radiologist the following morning and information relating to the number, time and type of reporting errors made as well as the body region scanned, indication for the scan, year of training of the registrar, and workload during the call were recorded and analyzed.
RESULTS: A total of 1477 CT scans were performed with an overall error rate of 17.1% and a major error rate of 7.7%. The error rate for 2nd, 3rd, and 4th year registrars was 19.4%, 15.1%, and 14.5%, respectively. A significant difference was found between the error rate in reporting trauma scans (15.8%) compared to non-trauma scans (19.2%) although the difference between emergency scans (16.9%) and elective scans (22.6%) was found to be not significant, a finding likely due to the low number of elective scans performed. Abdominopelvic scans elicited the highest number of errors (33.9%) compared to the other body regions such as head (16.5%) and cervical, thoracic, or lumbar spine (11.7%). Increasing workload resulted in a significant increase in error rate when analyzed with a generalized linear model. There was also a significant difference noted in the time of scan groups which we attributed to a workload effect. Missed findings were the most frequent errors seen (57.3%).
CONCLUSION: We found an increasing error rate associated with increasing workload and marked increase in errors with the reporting of abdominopelvic scans. There was a decrease in the error rate when looking an increasing year of training although this there was only found to be significant difference between the 2nd and 3rd year registrars.

PMID: 22302672 [PubMed - indexed for MEDLINE]

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Antimicrobial resistance among non-fermenting Gram-negative bacteria in Saudi Arabia.

J Antimicrob Chemother Start a Discussion »

Mar 312012

Antimicrobial resistance among non-fermenting Gram-negative bacteria in Saudi Arabia.

J Antimicrob Chemother. 2012 Mar 29;

Authors: Memish ZA, Shibl AM, Kambal AM, Ohaly YA, Ishaq A, Livermore DM

Abstract
OBJECTIVES: Non-fermentative Gram-negative bacilli (non-fermenters) can cause serious healthcare-associated infections and are often resistant to multiple antibiotics. We examined resistance rates among these bacteria from different regions of Saudi Arabia. METHODS: A cross-sectional study between January and December 2009 examined 8908 clinical non-fermenters from 24 hospitals across Saudi Arabia. Susceptibility testing was monitored to ensure compliance with CLSI guidelines, but the antibiotics tested were at the hospitals' discretion. RESULTS: Out of the 8908 non-fermenters, most were Pseudomonas aeruginosa (72.9%), followed by Acinetobacter baumannii (25.3%) and Stenotrophomonas maltophilia (1.8%). Resistance rates among P. aeruginosa were: polymyxin B, 2.2%; imipenem, 15.9%; ciprofloxacin, 22.0%; amikacin, 22.9%; and gentamicin, 31.2%. Resistance rates among A. baumannii were: imipenem, 5.4%; polymyxin B, 13.2%; ciprofloxacin, 64.0%; trimethoprim/sulfamethoxazole, 73.8%; amikacin, 76.9%; and gentamicin, 77.8%. Resistance rates among S. maltophilia were: polymyxin B, 6.9%; trimethoprim/sulfamethoxazole, 20.5%; and ciprofloxacin, 38.9%. There was major variation in resistance rates between geographical regions. CONCLUSIONS: Resistance rates among non-fermenters were high in Saudi Arabia and were variable among regions.

PMID: 22461312 [PubMed - as supplied by publisher]

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Oritavancin microbiologic features and activity results from the surveillance program in the United States.

Clin Infect Dis Start a Discussion »

Mar 312012

Oritavancin microbiologic features and activity results from the surveillance program in the United States.

Clin Infect Dis. 2012 Apr;54 Suppl 3:S203-13

Authors: Mendes RE, Farrell DJ, Sader HS, Jones RN

Abstract
Oritavancin is in the final stages of clinical development for treatment of acute bacterial skin and skin structure infections. This drug has demonstrated potent activity against staphylococci (minimum inhibitory concentration [MIC] for which 90% of isolates are inhibited [MIC(90)], 0.06 ?g/mL), enterococci (MIC(90), ?0.008 to 0.5 ?g/mL), and streptococci (MIC(90), ?0.008 to 0.12 ?g/mL), including enhanced potency against vancomycin-resistant enterococci. During the clinical development of oritavancin, it was demonstrated that this molecule binds to plastic labware surfaces and that this feature was likely responsible for interlaboratory variability observed from in vitro investigations before 2006. Therefore, reference broth microdilution methods and MIC ranges for quality control strains were reestablished using media supplemented with a surfactant (polysorbate-80, 0.002%). These were followed by numerous experiments to reassess the in vitro characteristics of oritavancin; the results originating from those studies are summarized here. The oritavancin activity tested against a resistance surveillance collection of 12?367 Gram-positive clinical pathogens and resistant subsets from the United States (2008-2009) is also presented, with the highest MIC among staphylococci at only 0.25 ?g/mL. In vitro results for oritavancin indicate wide potential use against Gram-positive pathogens.

PMID: 22431850 [PubMed - in process]

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Oritavancin: a new opportunity for outpatient therapy of serious infections.

Clin Infect Dis Start a Discussion »

Mar 312012

Oritavancin: a new opportunity for outpatient therapy of serious infections.

Clin Infect Dis. 2012 Apr;54 Suppl 3:S239-43

Authors: Tice A

Abstract
Oritavancin is a new antibiotic for the treatment of serious infections with Gram-positive bacteria. It has been shown to be effective against methicillin-susceptible and -resistant Staphylococcus aureus as well as enterococci. With a terminal half-life of 393 hours, oritavancin lends itself to a convenient and potentially cost-effective single-dose regimen. The single-dose regimen is currently being evaluated in pivotal phase 3 studies. This unique property provides an opportunity to assure consistent, effective, and safe treatment for serious infections while reducing the costs of care through the elimination of multiple infusions, reduced medical care staff, shorter hospital stays, and avoidance of hospital-acquired infections. These features seem ideal for the use of oritavancin in the outpatient management of serious infections. The impact that oritavancin will have on outpatient therapy is unclear. Current models will need to change with only a single infusion. Physician monitoring of the infection and underlying diseases may not be as frequent despite the need for close follow-up and frequent evaluations. There will be less need for a team of outpatient infusion specialists. Outpatient therapy will be compensated less without multiple infusions. With the possibility of fewer physician and other medical visits, there will be more responsibility for the patient and family and a reliance on patients to care for themselves. Although oritavancin offers tremendous theoretical advantages in the outpatient treatment of serious infections, care should be taken to assure the quality of care through changes in reimbursement, patient education, and development of systems to monitor care and outcomes.

PMID: 22431855 [PubMed - in process]

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Oritavancin: mechanism of action.

Clin Infect Dis Start a Discussion »

Mar 312012

Oritavancin: mechanism of action.

Clin Infect Dis. 2012 Apr;54 Suppl 3:S214-9

Authors: Zhanel GG, Schweizer F, Karlowsky JA

Abstract
Oritavancin is a semisynthetic lipoglycopeptide analogue of vancomycin that contains the heptapeptide core common to all glycopeptides. It differs from vancomycin by the presence of a hydrophobic N-4-(4-chlorophenyl)benzyl (also referred to as 4'-chlorobiphenylmethyl) substituent on the disaccharide sugar, the addition of a 4-epi-vancosamine monosaccharide to the amino acid residue in ring 6, and the replacement of the vancosamine moiety by 4-epi-vancosamine. One mechanism of action of oritavancin is inhibition of transglycosylation (important in peptidoglycan synthesis) by binding to D-alanyl-D-alanine stem termini in Gram-positive bacteria. The inhibition of peptidoglycan synthesis via inhibition of transglycosylation is common to all glycopeptides (vancomycin) and lipoglycopeptides. Secondary binding of oritavancin to the pentaglycyl (Asp/Asn) bridging segment in peptidoglycan also occurs, which distinguishes it from vancomycin and contributes to oritavancin's activity versus vancomycin-resistant organisms. The presence of the hydrophobic 4'-chlorobiphenylmethyl group allows for interaction and disruption of the cell membrane, resulting in depolarization, permeabilization, and concentration-dependent, rapid cell death. This mechanism is shared with telavancin but not vancomycin and results in activity against daptomycin-nonsusceptible organisms. In conclusion, oritavancin's mechanism of action involves at least 3 known mechanisms: inhibition of transglycosylation, inhibition of transpeptidation, and cell membrane interaction/disruption. Oritavancin's multiple mechanisms of action confer activity against vancomycin-susceptible and -resistant organisms, as well as rapid, concentration-dependent killing versus actively growing, stationary phase, and biofilm-producing Gram-positive bacteria.

PMID: 22431851 [PubMed - in process]

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