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Biomedical subjects

L Clifford McDonald

Publications and source records attributed to L Clifford McDonald.

At least 19 recordsLinked to original sources

Management of persistent bacteremia caused by methicillin-resistant Staphylococcus aureus: a survey of infectious diseases consultants.

We conducted a survey in 2005 of infectious diseases consultants and asked about persistent bacteremia due to methicillin-resistant Staphylococcus aureus. Many consultants perceived an increase in the frequency of illness, and, when presented with vancomycin minimum inhibitory concentrations approaching the limit of the susceptible range, most consultants indicated that they would switch to newer antimicrobial agents for treatment.

Anti-Bacterial Agents↗

Life-threatening sepsis caused by Burkholderia cepacia from contaminated intravenous flush solutions prepared by a compounding pharmacy in another state.

We report 2 life-threatening cases of Burkholderia cepacia sepsis caused by infusate contamination during compounding. Bacterial isolates from the patients' blood cultures and the infusate were indistinguishable by pulsed-field gel electrophoresis. Proper quality controls at a local and national level are important for ensuring safe delivery of compounded medications to patients in all settings, including those outside health care facilities.

Bacteremia↗

Cluster of cases of severe acute respiratory syndrome among Toronto healthcare workers after implementation of infection control precautions: a case series.

OBJECTIVE: To review the severe acute respiratory syndrome (SARS) infection control practices, the types of exposure to patients with SARS, and the activities associated with treatment of such patients among healthcare workers (HCWs) who developed SARS in Toronto, Canada, after SARS-specific infection control precautions had been implemented. METHODS: A retrospective review of work logs and patient assignments, detailed review of medical records of patients with SARS, and comprehensive telephone-based interviews of HCWs who met the case definition for SARS after implementation of infection control precautions. RESULTS: Seventeen HCWs from 6 hospitals developed disease that met the case definition for SARS after implementation of infection control precautions. These HCWs had a mean age (+/-SD) of 39+/-2.3 years. Two HCWs were not interviewed because of illness. Of the remaining 15, only 9 (60%) reported that they had received formal infection control training. Thirteen HCWs (87%) were unsure of proper order in which personal protective equipment should be donned and doffed. Six HCWs (40%) reused items (eg, stethoscopes, goggles, and cleaning equipment) elsewhere on the ward after initial use in a room in which a patient with SARS was staying. Use of masks, gowns, gloves, and eyewear was inconsistent among HCWs. Eight (54%) reported that they were aware of a breach in infection control precautions. HCWs reported fatigue due to an increased number and length of shifts; participants worked a median of 10 shifts during the 10 days before onset of symptoms. Seven HCWs were involved in the intubation of a patient with SARS. One HCW died, and the remaining 16 recovered. CONCLUSION: Multiple factors were likely responsible for SARS in these HCWs, including the performance of high-risk patient care procedures, inconsistent use of personal protective equipment, fatigue, and lack of adequate infection control training.

Adult↗

Improving antimicrobial use in the hospital setting by providing usage feedback to prescribing physicians.

OBJECTIVE: To determine whether feedback on antimicrobial use improves physician compliance with local hospital guidelines on antimicrobial prescribing. DESIGN: In this time series analysis, in which a historical control period was compared with an intervention period, all orders for antimicrobials (except those for surgical prophylaxis) placed from November 1, 2002, through April 30, 2004, were prospectively evaluated by an antimicrobial management team (AMT) for compliance with local hospital guidelines. During the control period, orders were evaluated to determine compliance with hospital guidelines before and after recommendations by the AMT were provided to physicians. Feedback was given for the second 9-month period in the form of a weekly report to prescribing physicians, a monthly hospital newsletter, and a quarterly report to various hospital committees. During the intervention period, orders were evaluated to determine compliance with hospital guidelines before and after recommendations by the AMT were provided to physicians. SETTING: The Veterans Affairs Medical Center, a 110-bed facility, in Louisville, Kentucky. PARTICIPANTS: Internal medicine physicians and general surgeons. RESULTS: A total of 2,807 antimicrobial courses were evaluated. Compliance with hospital guidelines before AMT recommendations was 70% during the control period and 74% during the intervention period (P=.02). Compliance after AMT recommendations was 90% during the control period and 93% during the intervention period (P< or =.01). CONCLUSION: The use of feedback had a significantly favorable impact on physician compliance with the hospital's guidelines on antimicrobial prescribing. Use of feedback should be added to the list of interventions that promote appropriate antimicrobial use in the hospital setting.

Anti-Bacterial Agents↗

Trends in antimicrobial resistance in health care-associated pathogens and effect on treatment.

Antimicrobial resistance in health care-associated pathogens is a growing concern for health care and for public health. A recent shift in the epidemiological profile of methicillin-resistant Staphylococcus aureus has resulted not only in health care-associated infections but now, also, in community-associated infections. Reports have described S. aureus exhibiting decreased susceptibility and, even, resistance to vancomycin. The rate of vancomycin resistance among enterococci may be leveling; however, vancomycin resistance in Enterococcus faecium has already achieved high levels. Multidrug resistance in Pseudomonas aeruginosa is increasing, and carbapenem-resistant Klebsiella strains are emerging. Acinetobacter species cause a minority of health care-associated pneumonias due to gram-negative organisms, but a growing proportion is resistant to carbapenems and third-generation cephalosporins. Recent increases in the frequency and severity of Clostridium difficile-associated illness are associated with the emergence of a hypervirulent C. difficile strain with increased resistance to the fluoroquinolones. The presence of these and other resistant organisms in health care facilities limits the number of effective antimicrobials available for treatment.

Anti-Bacterial Agents↗

Clostridium difficile infection in patients discharged from US short-stay hospitals, 1996-2003.

US hospital discharges for which Clostridium difficile-associated disease (CDAD) was listed as any diagnosis doubled from 82,000 (95% confidence interval [CI] 71,000-94,000) or 31/100,000 population in 1996 to 178,000 (95% CI 151,000-205,000) or 61/100,000 in 2003; this increase was significant between 2000 and 2003 (slope of linear trend 9.48; 95% CI 6.16-12.80, p = 0.01). The overall rate during this period was severalfold higher in persons >65 years of age (228/100,000) than in the age group with the next highest rate, 45-64 years (40/100,000; p < or = 0.001). CDAD appears to be increasing rapidly in the United States and is disproportionately affecting older persons. Clinicians should be aware of the increasing risk for CDAD and make efforts to control transmission of C. difficile and prevent disease.

Adolescent↗

Severe community-acquired pneumonia due to Staphylococcus aureus, 2003-04 influenza season.

During the 2003-04 influenza season, 17 cases of Staphylococcus aureus community-acquired pneumonia (CAP) were reported from 9 states; 15 (88%) were associated with methicillin-resistant S. aureus (MRSA). The median age of patients was 21 years; 5 (29%) had underlying diseases, and 4 (24%) had risk factors for MRSA. Twelve (71%) had laboratory evidence of influenza virus infection. All but 1 patient, who died on arrival, were hospitalized. Death occurred in 5 (4 with MRSA). S. aureus isolates were available from 13 (76%) patients (11 MRSA). Toxin genes were detected in all isolates; 11 (85%) had only genes for Panton-Valentine leukocidin. All isolates had community-associated pulsed-field gel electrophoresis patterns; all MRSA isolates had the staphylococcal cassette chromosome mec type IVa. In communities with a high prevalence of MRSA, empiric therapy of severe CAP during periods of high influenza activity should include consideration for MRSA.

Adolescent↗

ICD-9 codes and surveillance for Clostridium difficile-associated disease.

We conducted a retrospective cohort study to compare Clostridium difficile-associated disease rates determined by C. difficile-toxin assays and International Classification of Diseases, 9th Revision (ICD-9) codes. The correlation between toxin assay results and ICD-9 codes was good (K = 0.72, p<0.01). The sensitivity of the ICD-9 codes was 78% and the specificity was 99.7%.

Bacterial Toxins↗

Clostridium difficile-associated disease: new challenges from an established pathogen.

Clostridium difficile-associated disease (CDAD) can range from uncomplicated diarrhea to sepsis and even death. CDAD rates and severity are increasing, possibly due to a new strain. Transmission of C difficile occurs primarily in health care facilities via the fecal-oral route following transient contamination of the hands of health care workers and patients; contamination of the patient care environment also plays an important role.

Anti-Bacterial Agents↗

An epidemic, toxin gene-variant strain of Clostridium difficile.

BACKGROUND: Recent reports suggest that the rate and severity of Clostridium difficile-associated disease in the United States are increasing and that the increase may be associated with the emergence of a new strain of C. difficile with increased virulence, resistance, or both. METHODS: A total of 187 C. difficile isolates were collected from eight health care facilities in six states (Georgia, Illinois, Maine, New Jersey, Oregon, and Pennsylvania) in which outbreaks of C. difficile-associated disease had occurred between 2000 and 2003. The isolates were characterized by restriction-endonuclease analysis (REA), pulsed-field gel electrophoresis (PFGE), and toxinotyping, and the results were compared with those from a database of more than 6000 isolates obtained before 2001. The polymerase chain reaction was used to detect the recently described binary toxin CDT and a deletion in the pathogenicity locus gene, tcdC, that might result in increased production of toxins A and B. RESULTS: Isolates that belonged to one REA group (BI) and had the same PFGE type (NAP1) were identified in specimens collected from patients at all eight facilities and accounted for at least half of the isolates from five facilities. REA group BI, which was first identified in 1984, was uncommon among isolates from the historic database (14 cases). Both historic and current (obtained since 2001) BI/NAP1 isolates were of toxinotype III, were positive for the binary toxin CDT, and contained an 18-bp tcdC deletion. Resistance to gatifloxacin and moxifloxacin was more common in current BI/NAP1 isolates than in non-BI/NAP1 isolates (100 percent vs. 42 percent, P<0.001), whereas the rate of resistance to clindamycin was the same in the two groups (79 percent). All of the current but none of the historic BI/NAP1 isolates were resistant to gatifloxacin and moxifloxacin (P<0.001). CONCLUSIONS: A previously uncommon strain of C. difficile with variations in toxin genes has become more resistant to fluoroquinolones and has emerged as a cause of geographically dispersed outbreaks of C. difficile-associated disease.

ADP Ribose Transferases↗

A national survey of severe influenza-associated complications among children and adults, 2003-2004.

This report summarizes findings of a national survey conducted among infectious diseases consultants to assess complications associated with influenza during the 2003-2004 influenza season. The survey identified severe complications, including secondary infection with Staphylococcus aureus and deaths among children and adults, as well as perceived shortages in rapid diagnostic tests and influenza vaccine.

Adolescent↗

Vancomycin-resistant staphylococci and enterococci: epidemiology and control.

PURPOSE OF REVIEW: This review updates information on the development and spread of vancomycin resistance in staphylococci and enterococci. RECENT FINDINGS: New information on the genetic characterization of vancomycin-resistant Staphylococcus aureus isolates from the US indicates that each of the four was the result of an independent genetic event. New data suggest that vancomycin-intermediate S. aureus isolates, particularly those showing heteroresistance, are clinically significant. Finally, vancomycin-resistant enterococci continue to be reported from around the world. Novel infection control measures, however, may aid in reducing the spread of these organisms in healthcare settings. SUMMARY: The exchange of genetic information, particularly the vanA gene, between and among staphylococci and enterococci will continue to challenge physicians, microbiologists, and infection control practitioners in efforts to identify, treat, and prevent infections with these pathogens.

Enterococcus↗

Colonization of human immunodeficiency virus-infected outpatients in Taiwan with Candida species.

To understand the Candida colonization of human immunodeficiency virus (HIV)-infected outpatients in Taiwan, we have conducted a prospective cohort study of Candida colonization and its risk factors at the National Taiwan University Hospital from 1999 to 2002. More than 50% of the patients were colonized with Candida species, and 12% developed symptomatic candidiasis. Patients colonized with fluconazole-resistant strains of Candida species had a higher prevalence of candidiasis than those colonized with susceptible strains. Our analysis found that antibiotic treatment and lower CD4(+) counts (<200 cells/mm(3)) increased the rate of oropharyngeal candidiasis in HIV-infected patients, while antiretroviral therapy protected patients from the development of candidiasis.

AIDS-Related Opportunistic Infections↗

Late recognition of SARS in nosocomial outbreak, Toronto.

Late recognition of severe acute respiratory syndrome (SARS) was associated with no known SARS contact, hospitalization before the nosocomial outbreak was recognized, symptom onset while hospitalized, wards with SARS clusters, and postoperative status. SARS is difficult to recognize in hospitalized patients with a variety of underlying conditions in the absence of epidemiologic links.

Aged↗

The status of antimicrobial resistance in Taiwan among gram-negative pathogens: the Taiwan surveillance of antimicrobial resistance (TSAR) program, 2000.

In a nationwide surveillance of antimicrobial resistance (Taiwan Surveillance of Antimicrobial Resistance, TSAR), isolates were collected from 21 medical centers and regional hospitals throughout Taiwan over a three-month period in 2000 (TSAR II). This report summarizes susceptibility data of 7 common Gram-negative bacilli (Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Proteus mirabilis, Enterobacter cloacae, Pseudomonas aeruginosa, and Acinetobacter baumannii) in the TSAR II collection and compared selected key forms of resistance by epidemiologic factors and with isolates collected in 1998 (TSAR I) as well as with data from international surveillance studies. Resistance of the 5 Enterobacteriaceae species to most of the commonly prescribed "first-line" antimicrobials in Taiwan, such as ampicillin (78% in E. coli, 68% in P. mirabilis), gentamicin (19% in K. pneumonia to 66% in S. marcescens), and trimethoprim/sulfamethoxazole (29% in K. pneumoniae to 70% in P. mirabilis), was high, several of which are higher than other countries. Resistance to certain broad-spectrum antimicrobials is also more acute in Taiwan than most Western countries, such as ceftazidime resistant A. baumannii (73%) and ciprofloxacin resistant E. coli (12%). Differences in geographic regions and specimen types were associated with certain forms of resistance in TSAR II; however, the resistance problem is prevalent among both inpatients and outpatients of not only medical centers but also regional hospitals throughout Taiwan.

Anti-Bacterial Agents↗