Biomedical subjects

Roberta B Carey

Publications and source records attributed to Roberta B Carey.

8 recordsLinked to original sources

PubMed2006

Methicillin-resistant S. aureus infections among patients in the emergency department.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly recognized in infections among persons in the community without established risk factors for MRSA. METHODS: We enrolled adult patients with acute, purulent skin and soft-tissue infections presenting to 11 university-affiliated emergency departments during the month of August 2004. Cultures were obtained, and clinical information was collected. Available S. aureus isolates were characterized by antimicrobial-susceptibility testing, pulsed-field gel electrophoresis, and detection of toxin genes. On MRSA isolates, we performed typing of the staphylococcal cassette chromosome mec (SCCmec), the genetic element that carries the mecA gene encoding methicillin resistance. RESULTS: S. aureus was isolated from 320 of 422 patients with skin and soft-tissue infections (76 percent). The prevalence of MRSA was 59 percent overall and ranged from 15 to 74 percent. Pulsed-field type USA300 isolates accounted for 97 percent of MRSA isolates; 74 percent of these were a single strain (USA300-0114). SCCmec type IV and the Panton-Valentine leukocidin toxin gene were detected in 98 percent of MRSA isolates. Other toxin genes were detected rarely. Among the MRSA isolates, 95 percent were susceptible to clindamycin, 6 percent to erythromycin, 60 percent to fluoroquinolones, 100 percent to rifampin and trimethoprim-sulfamethoxazole, and 92 percent to tetracycline. Antibiotic therapy was not concordant with the results of susceptibility testing in 100 of 175 patients with MRSA infection who received antibiotics (57 percent). Among methicillin-susceptible S. aureus isolates, 31 percent were USA300 and 42 percent contained pvl genes. CONCLUSIONS: MRSA is the most common identifiable cause of skin and soft-tissue infections among patients presenting to emergency departments in 11 U.S. cities. When antimicrobial therapy is indicated for the treatment of skin and soft-tissue infections, clinicians should consider obtaining cultures and modifying empirical therapy to provide MRSA coverage.

Acute Disease↗

PubMed2006

Investigation of inducible clindamycin and telithromycin resistance in isolates of beta-hemolytic streptococci.

We evaluated the accuracy of an erythromycin-clindamycin double-disk test (D-zone test) and an erythromycin-telithromycin D-zone test for detection of inducible resistance in isolates of beta-hemolytic streptococci with erythromycin resistance. The results of these tests were compared to results of a broth microdilution (BMD) induction test using combinations of erythromycin and either clindamycin or telithromycin. Of 29 erythromycin-resistant, clindamycin-susceptible isolates, 16 were positive by the erythromycin-clindamycin D-zone test; all of these demonstrated inducible clindamycin resistance by BMD. Twelve isolates were D-zone test-negative, did not demonstrate inducible resistance by BMD, and were positive for a mef determinant. Of 39 erythromycin-resistant, telithromycin-susceptible isolates, 13 were erythromycin-telithromycin D-zone test-positive, 19 questionably positive (unclear blunting of the zone), and 7 were D-zone test-negative. The erythromycin-telithromycin D-zone test result did not correlate with inducible resistance by BMD or the presence of an erm or mef gene. These results demonstrate that the erythromycin-clindamycin D-zone and BMD induction tests accurately detect inducible clindamycin resistance, but the erythromycin-telithromycin D-zone test is not reliable for detecting inducible telithromycin resistance.

Anti-Bacterial Agents↗

PubMed2006

Carbapenem resistance in Klebsiella pneumoniae not detected by automated susceptibility testing.

Detecting beta-lactamase-mediated carbapenem resistance among Klebsiella pneumoniae isolates and other Enterobacteriaceae is an emerging problem. In this study, 15 blaKPC-positive Klebsiella pneumoniae that showed discrepant results for imipenem and meropenem from 4 New York City hospitals were characterized by isoelectric focusing; broth microdilution (BMD); disk diffusion (DD); and MicroScan, Phoenix, Sensititre, VITEK, and VITEK 2 automated systems. All 15 isolates were either intermediate or resistant to imipenem and meropenem by BMD; 1 was susceptible to imipenem by DD. MicroScan and Phoenix reported 1 (6.7%) and 2 (13.3%) isolates, respectively, as imipenem susceptible. VITEK and VITEK 2 reported 10 (67%) and 5 (33%) isolates, respectively, as imipenem susceptible. By Sensititre, 13 (87%) isolates were susceptible to imipenem, and 12 (80%) were susceptible to meropenem. The VITEK 2 Advanced Expert System changed 2 imipenem MIC results from >16 ?g/mL to <2 ?g/mL but kept the interpretation as resistant. The recognition of carbapenem-resistant K. pneumoniae continues to challenge automated susceptibility systems.

Anti-Bacterial Agents↗

PubMed2005

Potassium sorbate reduces gastric colonization in patients receiving mechanical ventilation.

OBJECTIVES: Tube feeding might increase gastric burden of pathogenic bacteria and predispose patients to ventilator-associated pneumonia. We sought to determine whether a tube feeding formula acidified using potassium sorbate could reduce gastric burden of potentially pathogenic bacteria. DESIGN: Prospective, randomized, double-blind trial. SETTING: RML Specialty Hospital, a facility with expertise in weaning patients from prolonged mechanical ventilation. PATIENTS: Thirty patients recovering from prolonged mechanical ventilation. INTERVENTION: Patients were randomized to receive either a standard tube feeding formula (n=14) or a formula acidified using potassium sorbate to a pH of 4.25 (n=16). MEASUREMENTS AND RESULTS: Weekly quantitative cultures of gastric aspirates. The number of colony-forming units (CFUs) per patient was higher in the control than in the treatment group (53%+/-11% vs 9%+/-3.4%, threshold of >or=100,000 CFU/mL fluid, P=.003). The number of organisms isolated in each patient per week was higher among patients receiving standard tube feeding formula than among patients receiving acidified formula (0.91 +/- 0.20 vs 0.13 +/- 0.05 organisms per patient per week, threshold of >or=100,000 CFU/mL fluid, P=.0014). There was no difference in the incidence of gastrointestinal bleeding or ventilator-associated pneumonia between study groups. CONCLUSION: Tube feeding formula acidified using potassium sorbate was well tolerated and reduced gastric bacterial burden in patients recovering from prolonged mechanical ventilation.

Aged↗

PubMed2004

Tuberculous tenosynovitis.

Tuberculous tenosynovitis is rare and may be overlooked as a cause of chronic tenosynovitis. This report presents a case of a young woman with tuberculosis tenosynovitis of the wrist, and highlights the clinical, imaging, histological, and laboratory features most commonly seen in this disease.

Adult↗

PubMed2004

Fatal hemorrhagic pneumonia concomitant with Chlamydia pneumoniae and parainfluenza virus 4 infection.

CONTEXT: Cases of fatal hemorrhagic pneumonia need to be investigated for highly contagious viral causes. While not all hemorrhagic pneumonias are caused by very contagious agents, the etiology must be correctly determined in order to administer appropriate patient care. OBJECTIVE: To determine whether chlamydia, paramyxovirus, or mycoplasma was the causative agent in a case of fatal hemorrhagic pneumonia, and to evaluate the possibility that this was the first case of hantavirus pulmonary syndrome in Illinois. DESIGN: Nonroutine virological and molecular analyses were performed on lung tissue taken during an unrestricted autopsy of a patient who died in 2002. SETTING AND PATIENT: An elderly, male, Chicago-area resident with a 3-week history of nonspecific, mild upper respiratory tract infection was admitted for hospital treatment of the respiratory infection and viral myositis without cardiac involvement. The patient became febrile, hypoxic, developed hemorrhagic pneumonia, and died. Because he had proven exposure to mice and had developed hemorrhagic pneumonia, hantavirus pulmonary syndrome was suspected as the cause of death. Mice known to carry hantaviruses live in Illinois, including the Chicago area. INTERVENTIONS: Gatifloxacin and heparin anticoagulation were initiated because community-acquired pneumonia and pulmonary embolism were considered likely etiologies for an acute exacerbation of hypoxemia. RESULTS: Two respiratory pathogens were isolated and identified: Chlamydia pneumoniae and human parainfluenza virus 4a. CONCLUSIONS: A mixed (polymicrobial) infection contributed to the patient's death. Hemorrhage was likely a result of anticoagulation therapy superimposed on lung tissues damaged by pneumonia. The uncommon nature of this case and the pathogens involved underscore the challenges in infection control and clinical evaluation that hospitals will face when confronted with possibly new and potentially deadly communicable diseases.

Aged↗

PubMed2003

In vitro study of bacterial adherence to processed dura mater, processed pericardium, pericardium in saline, and human sclera.

PURPOSE: To study bacterial adherence to processed dura mater, processed pericardium, pericardium in saline, and human sclera and the difference in bacterial adherence to these tissues. SETTING: Research Laboratory, Loyola University Medical Center, Maywood, Illinois, USA. METHODS: Specimens of processed dura mater, processed human pericardium, pericardium in saline, and human sclera (N = 32) were exposed to Staphylococcus epidermidis (concentration 3 x 10(8)) for 10, 20, 40, and 60 minutes, washed for 5 seconds, fixed, and processed for scanning electron microscopy (SEM). Each bacterial count represents an average of 50 random SEM fields at x5,000 magnification. After SEM, selected specimens were processed for transmission electron microscopy. RESULTS: The mean number of bacteria/mm(2) +/- SD adhering to the tissues at 10, 20, 40, and 60 minutes, respectively, were dura mater, 107,833 +/- 65,410, 104,500 +/- 13,471, 96,067 +/- 113,884, and 204,267 +/- 153,697; processed pericardium, 131,550 +/- 86,194, 100,900 +/- 20,031, 144,683 +/- 51,730, and 176,933 +/- 111,818; pericardium in saline, 7,925 +/- 1,520, 33,933 +/- 32,085, 1,217 +/- 1,287, and 21,550 +/- 16,436; and human sclera, 4,850 +/- 2,121, 23,700 +/- 17,961, 5,150 +/- 1,273, and 8,175 +/- 8,450. A 2-way analysis of variance showed significant differences among groups (P =.001) and no significant difference in sample time (P =.929). CONCLUSIONS: Bacterial adherence to processed dura mater, processed pericardium, pericardium in saline, and human sclera should be considered when these materials are used clinically during ophthalmic surgery and other surgical specialties. Adequate broad-spectrum antibiotic coverage is needed to prevent infection and subsequent complications in patients.

Bacterial Adhesion↗

PubMed2003

Staphylococcus epidermidis adherence to human amniotic membrane and to human, rabbit, and cat conjunctiva.

PURPOSE: To evaluate Staphylococcus epidermidis adherence to human amniotic membrane (HAM) and compare it with S epidermidis adherence to human, rabbit, and cat conjunctiva in vitro. SETTING: Research laboratory, Loyola University Medical Center, Maywood, Illinois, USA. METHODS: Commercially available HAM (N = 3) was used. Conjunctival specimens from humans, rabbits, and cats (n = 3 each) were processed similarly to HAM. The tissues were exposed to S epidermidis (3 x 10(8) colony-forming units per milliliter) for 0, 5, 30, and 90 minutes, rinsed in sterile saline, and processed for light, scanning (SEM), and transmission (TEM) electron microscopy. Scanning electron microscopy (x2000) was used to quantify adherent bacteria/mm(2) of tissue (SEM photographs = 144). RESULTS: The following mean levels (+/- SD) of adherent S epidermidis/mm(2) were found at 0, 5, 30, and 90 minutes: HAM, 3833 +/- 1570, 9060 +/- 2512, 15,431 +/- 10,752, and 30,315 +/- 14,803, respectively; human conjunctiva, 1493 +/- 672, 7218 +/- 3179, 17,273 +/- 7168, and 19,861 +/- 9624, respectively; rabbit conjunctiva, 3385 +/- 5074, 14,386 +/- 14,569, 15,283 +/- 13,679, and 20,113 +/- 24,016, respectively; and cat conjunctiva, 4032 +/- 2240, 12,345 +/- 3413, 8512 +/- 4032, and 19,214 +/- 5584, respectively. No statistically significant differences were found at any time point (P>.16). CONCLUSION: There was no statistically significant difference in the adherence of S epidermidis to HAM and to human, rabbit, and cat conjunctiva. Bacterial adherence to HAM may be clinically significant.

Amnion↗