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Biomedical subjects

David P Dooley

Publications and source records attributed to David P Dooley.

At least 19 recordsLinked to original sources
PubMed2006

Culture-negative surgical site infections.

BACKGROUND: The appearance of postoperative surgical site infection (SSI) in the absence of culturable bacterial pathogens is a common dilemma for the surgeon. METHODS: The literature was searched through references to primary articles, as well as a MEDLINE review, for reports of culture-negative SSIs. RESULTS: Potential causes of culture-negative SSIs include prior antimicrobial therapy; the presence of fastidious or slow-growing microorganisms such as mycobacteria, Mycoplasma spp., and Legionella spp.; infection caused by mundane bacteria that may be dismissed as "contaminants"; factitious infection; and others. CONCLUSIONS: We review the recognized causes of "culture negative" SSIs and discuss the laboratory capabilities that may enhance recognition of many of these pathogens and management options.

Culture Media↗
PubMed2006

Prospective study of bacterial and viral contamination of exercise equipment.

OBJECTIVE: Transmission of bacterial and viral pathogens is known to occur by hand contact with fomites. Exercise equipment in public facilities may serve as such fomites. It is not known whether equipment disinfection might reduce microorganism colonization. We performed studies to address these issues. DESIGN: Observational study of bacterial and viral culture results from hand-contact surfaces of exercise equipment, pre-exercise and postexercise; prospective study of viral culture results before and after intervention with disinfection solution. SETTING: Two fitness centers in a military community. INTERVENTION: One week trial of twice-a-day equipment disinfection. MAIN OUTCOME MEASURES: Type and number of bacteria and type of viruses present on equipment before and after exercise; prevalence of viral culture positivity on equipment before and after intervention. RESULTS: Bacterial cultures of body contact surfaces on equipment revealed benign bacterial species (coagulase-negative staphylococci, diphtheroids, and so forth) but no pathogenic bacteria whether obtained pre-exercise or postexercise, or whether from aerobic versus weight training equipment. Viral cultures revealed the presence of viruses (generally rhinoviruses) on 63 of 100 (63%) hand-contact surfaces of equipment. Weight equipment was significantly more often contaminated than aerobic equipment (73% vs. 51%; P = 0.026). Disinfection of equipment did not lower the prevalence of virus isolation (48% positive before cleaning; 86% positive after cleaning). CONCLUSIONS: There is little risk of exposure to pathogenic bacteria on exercise equipment. Such equipment may commonly serve as fomites for the transmission of viruses. These data do not suggest that disinfection of exercise equipment will offer significant protective effects against virus exposure.

Bacteria↗
PubMed2006

Outcomes of community-acquired, methicillin-resistant Staphylococcus aureus, soft tissue infections treated with antibiotics other than vancomycin.

Community-acquired, methicillin-resistant Staphylococcus aureus (cMRSA), soft tissue infections are becoming increasingly prevalent in the outpatient setting. Few studies have been specifically designed to examine the efficacy of oral antibiotic therapy for these infections. We performed an observational study to determine the effect of alternative, orally administered antibiotics on cMRSA soft tissue infections. Consecutive patients between January 2001 and March 2004 who had skin or soft tissue infections from which cMRSA was isolated and who had never received vancomycin were studied through retrospective and concurrent review. Primary outcome measures were improvement or resolution of infection 5 and 14 days after initiation of treatment with orally administered antibiotics and rates of recurrence within 30 days after completion of treatment. Thirty subjects met the inclusion criteria. Twenty-one subjects received either clindamycin, trimethoprim/sulfamethoxazole, doxycycline/minocycline, or a fluoroquinolone. Five subjects received a beta-lactam antibiotic with abscess drainage, and four subjects underwent abscess drainage alone. Improvement was noted for all subjects at 5 days, complete resolution of infection occurred for all subjects by 14 to 17 days, and in no case did relapse occur within 30 days. cMRSA skin and soft tissue infections can be successfully treated with orally administered antibiotics to which the organism has demonstrable in vitro susceptibility.

Adolescent↗
PubMed2006

Bacteria recovered from patients admitted to a deployed U.S. military hospital in Baghdad, Iraq.

The predominant bacteria and antimicrobial susceptibilities were surveyed from a deployed, military, tertiary care facility in Baghdad, Iraq, serving U.S. troops, coalition forces, and Iraqis, from August 2003 through July 2004. We included cultures of blood, wounds, sputum, and urine, for a total of 908 cultures; 176 of these were obtained from U.S. troops. The bacteria most commonly isolated from U.S. troops were coagulase-negative staphylococci, accounting for 34% of isolates, Staphylococcus aureus (26%), and streptococcal species (11%). The 732 cultures obtained from the predominantly Iraqi population were Klebsiella pneumoniae (13%), Acinetobacter baumannii (11%), and Pseudomonas aeruginosa (10%); coagulase-negative staphylococci represented 21% of these isolates. These differences in prevalence were all statistically significant, when compared in chi2 analyses (p < 0.05). Antimicrobial susceptibility testing demonstrated broad resistance among the Gram-negative and Gram-positive bacteria.

Acinetobacter baumannii↗
PubMed2006

Bacteriology of war wounds at the time of injury.

Bacterial contamination of war wounds occurs either at the time of injury or during the course of therapy. Characterization of the bacteria recovered at the time of initial trauma could influence the selection of empiric antimicrobial agents used to prevent infection. In the spring of 2004, U.S. military casualties who presented to the 31st Combat Support Hospital in Baghdad, Iraq, with acute traumatic injuries resulting in open wounds underwent aerobic culture of their wounds to identify the bacteria colonizing the wounds. Forty-nine casualties with 61 separate wounds were evaluated. Wounds were located predominantly in the upper and lower extremities and were primarily from improvised explosive devices or mortars. Thirty wounds (49%) had bacteria recovered on culture, with 40 bacteria identified. Eighteen casualties (20 wounds) had undergone field medical therapy (irrigation and/or antimicrobial treatment); six of these had nine bacterial isolates on culture. Of the 41 wounds from 31 patients who had received no previous therapy, 24 grew 31 bacteria. Gram-positive bacteria (93%), mostly skin-commensal bacteria, were the predominant organisms identified. Only three Gram-negative bacteria were detected, none of which were characterized as broadly resistant to antimicrobial agents. The only resistant bacteria recovered were two isolates of methicillin-resistant Staphylococcus aureus (MRSA). Our assessment of war wound bacterioly soon after injury reveals a predominance of Gram-positive organisms of low virulence and pathogenicity. The presence of MRSA in wounds likely reflects the increasing incidence of community-acquired MRSA bacteria. These data suggest that the use of broad-spectrum antibiotics with efficacy against more resistant, Gram-negative bacteria, such as Pseudomonas aeruginosa and Acinetobacter spp., is unnecessary in early wound management.

Anti-Bacterial Agents↗
PubMed2005

History of U.S. military contributions to the study of viral hepatitis.

Epidemic jaundice, although known by armies since ancient times, became a concern of the U.S. military only after outbreaks occurred during World War II. Early work by military investigators defined, for the first time, the existence of two different forms of hepatitis. Subsequently, investigators described the effective prevention of symptomatic hepatitis using immune serum globulin. Military researchers contributed to the isolation of and testing for the virus of infectious hepatitis, work that was then instrumental in the designing and fielding of a hepatitis A vaccine. Hepatitis B contributions included the elaboration of community-based epidemiology and description of the efficacy of immune serum globulin prophylaxis. Most recently, studies on hepatitis E defined the epidemiology, performed genomic sequencing, and developed a DNA vaccine currently being tested against the disease. Major research contributions to the understanding of and protection against viral hepatitis have been made by the military medical establishment over the past 60 years.

Biomedical Research↗
PubMed2004

Natural history of community-acquired methicillin-resistant Staphylococcus aureus colonization and infection in soldiers.

BACKGROUND: Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging pathogen for which the prevalence, risk factors, and natural history are incompletely understood. METHODS: In this prospective observational study, we evaluated 812 US Army soldiers to determine the prevalence of and risk factors for CA-MRSA colonization and the changes in colonization rate over time, as well as to determine the clinical significance of CA-MRSA colonization. Demographic data and swab samples from the nares for S. aureus cultures were obtained from participants at the start of their training and 8-10 weeks later. Over this time period, participants were observed prospectively to monitor for soft-tissue infections. S. aureus isolates were characterized by in vitro examination of antibiotic susceptibilities, mecA confirmation, pulsed-field gel electrophoresis, and Panton-Valentine leukocidin (PVL) gene testing. RESULTS: At the initial sampling, 24 of the participants (3%) were colonized with CA-MRSA, 9 of whom (38%) developed soft-tissue infections during the study period. In contrast, 229 participants (28%) were colonized with methicillin-susceptible S. aureus (MSSA), 8 (3%) of whom developed clinical infections during the same period (relative risk, 10.7; 95% confidence interval, 4.6-25.2; P<.001). At follow-up culture, the CA-MRSA colonization rate dropped to 1.6% without eradication efforts. Previous antibiotic use was a risk factor for CA-MRSA colonization at the initial sampling (P=.03). PVL genes were detected in 66% of 45 recovered CA-MRSA isolates, including all 9 clinical isolates available for analysis. Of subjects hospitalized, 5 of 6 had PVL-positive CA-MRSA infections. CONCLUSIONS: CA-MRSA colonization with PVL-positive strains was associated with a significant risk of soft-tissue infection, suggesting that CA-MRSA may be more virulent than MSSA. Previous antibiotic use may play a role in CA-MRSA colonization.

Abscess↗
PubMed2004

Frequency of vaccinia virus isolation on semipermeable versus nonocclusive dressings covering smallpox vaccination sites in hospital personnel.

BACKGROUND: The Centers for Disease Control and Prevention recommends a semipermeable occlusive dressing for hospital workers who receive smallpox vaccination. OBJECTIVE: The study was designed to determine the frequency of vaccinia virus isolation from the outer surface of semipermeable dressings and to compare the prevalence of vaccinia virus on the outer surface of semipermeable dressings with its prevalence on the outer surface of nonocclusive dressings. METHODS: A prospective, observational study was conducted on hospital employees who received smallpox vaccination at a military academic medical center. Subjects were instructed to wear a semipermeable dressing if they had direct patient contact. Employees without direct patient care had the option of wearing a semipermeable dressing or a nonocclusive dressing. Prior to a programmed dressing change, the outer surface of the bandage site was swabbed and cultured for virus. Samples were considered positive when cytopathic effects were observed, with results confirmed as vaccinia by polymerase chain reaction. RESULTS: A total of 212 cultures were obtained from 93 subjects. All cultures directly obtained from active lesions were positive (13/13). Positive cultures were obtained from 7% (10/135) of the semipermeable dressings and 23% (15/64) of the nonocclusive dressings (P <.05). Ten percent (8/79) of the semipermeable dressings with purulent exudate observed underneath the bandage were culture positive, compared with 4% (2/56) of semipermeable dressings with no purulent exudate observed underneath the bandage (P=.19). CONCLUSIONS: Compared with nonocclusive dressings, the semipermeable dressing reduced, but did not eliminate, the frequency with which vaccinia virus was cultured from the surface of the dressing. Virus was present, but only rarely, on the dressing surface in the absence of purulent exudate under the semipermeable dressings.

Bandages↗
PubMed2004

The effect of moving to a new hospital facility on the prevalence of methicillin-resistant Staphylococcus aureus.

BACKGROUND: The influence of hospital design on nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) is unknown. Our hospital's relocation to a new building with radically different ward design allowed us to study this question. Our old hospital facility had open bay wards and intensive care units, and few poorly located sinks for handwashing (bed:sink ratio 4:1). Our new hospital facility had optimized hand-washing geography and distribution of ward beds into mostly single or double rooms (bed:sink ratio 1.3:1). METHODS: We compared the prevalence of MRSA in the 2 institutions by obtaining nasal swabs from all patients on 8 selected wards and intensive care units at 2 time points both before and after the move. In addition, passive surveillance rates of MRSA for all hospitalized patients for 2 years both before and after the move were compared. Hand hygiene practices, although unrelated to the study periods, were directly observed. RESULTS: Eight of 123 patients cultured before the move were MRSA positive, compared to 5 of 138 patients cultured after the move (P=NS). MRSA prevalence determined by passive surveillance of all hospitalized patients before and after the move was also unchanged. An insignificant increase in the frequency of hand-hygiene performance following the move (20% to 23%) was observed. CONCLUSION: Radical facility design changes, which would be permissive of optimal infection control practices, were not sufficient, by themselves, to reduce the nosocomial spread of MRSA in our institution.

Analysis of Variance↗
PubMed2004

The effect of semipermeable dressings on smallpox vaccine site evolution.

BACKGROUND: Many hospital systems in the United States are contemplating the implementation of a smallpox vaccination program. The Centers for Disease Control and Prevention and other organizations recommend use of occlusive dressings over the vaccination site of health care workers in contact with patients. Minimal data are available on the impact of an occlusive dressing on the evolution of the vaccinia inoculation site. METHODS: We conducted a prospective observational study in which subjects were instructed to cover their vaccination site with either a semipermeable dressing over gauze or gauze alone. We recorded the duration of semipermeable dressing use and parameters pertaining to vaccination site evolution, to include time until scab separation. RESULTS: The increased use of a semipermeable dressing is associated with increased time until scab separation (n = 41, r =.48, P =.001 by regression analysis). This analysis predicts a 9-day difference in time until scab separation between patients that wore semipermeable dressings 100% of the time versus not at all. No significant correlation was observed between semipermeable dressing use and size of maximum erythema, time until maximum erythema, size of erythema on day 6 or 8, nor time until pustule formation. CONCLUSION: Semipermeable dressing use appears to prolong the time until scab separation and possibly the duration of infectivity and risk of secondary transmission. Health care organizations may wish to consider this information when instituting a smallpox vaccination program.

Adult↗
PubMed2004

Coccidioidomycosis mimicking ovarian cancer.

BACKGROUND: Dissemination of coccidioidomycosis to the abdominal cavity is rare. No previous case of peritoneal coccidioidomycosis has presented as an adnexal mass. CASE: We report a case of peritoneal coccidioidomycosis mimicking ovarian carcinoma. The patient presented with a complex ovarian mass, ascites, omental caking, and an elevated CA 125. The ultimate diagnosis was not made until frozen section histopathology was performed at staging laparotomy. CONCLUSION: Peritoneal coccidioidomycosis can present with the clinical, radiographic, and serologic features of ovarian cancer. Although essential for diagnosis and staging, radiographic studies and tumor markers have limited specificity. Coccidioidomycosis now joins other benign conditions that comprise the differential diagnosis of patients who present with what seems to be advanced ovarian carcinoma. Infectious diseases consultation is recommended for the management of peritoneal coccidioidomycosis.

Adult↗
PubMed2004

Bullis fever: a vanished infection of unknown etiology.

Camp Bullis, Texas, is an active training facility for the U.S. Army and Air Force with a storied history dating back to the late 19th century. In the early 1940s, an epidemic of a seasonal tick-borne rickettsial-like illness occurred at Camp Bullis; the last case was reported in 1947. To date, the etiology of this disease has remained elusive. In an attempt to retrospectively identify the causal pathogen, we surveyed Camp Bullis for the presumed tick vector with intent to screen molecularly for Rickettsia and Ehrlichia. However, no ticks were recovered from primary dragging attempts in the spring or from harvested deer in the fall. Moreover, pathologic and microbiologic materials obtained during the epidemic are no longer extant, making them unavailable for analysis. In this study, we review potential circumstances that impact emerging and, in this case, vanishing infections. The etiology of Bullis fever will probably remain undetermined, and this once-emerging infection may have vanished into history. However, given Camp Bullis' status as an active medical training site, awareness of and surveillance for the disease should continue.

Animals↗
PubMed2004

Experience with directly observed prophylaxis using erythromycin in military trainees exposed to pertussis.

Pertussis, once a serious respiratory disease in children, has recently been identified as a common cause of chronic cough in adults. Military personnel are known to be vulnerable to this disease. After a training barracks exposure to pertussis, routine arrangements for contact prophylaxis with erythromycin failed. This experience is reported here as well as that of our subsequent aggressive attempts using directly observed prophylaxis (DOP) with standard erythromycin regimens. No secondary cases occurred. However, many contacts (35%) could not finish a 14-day course despite DOP, mostly because of nausea (85%) or diarrhea (72%). Seventeen (18%) soldiers missed classes because of erythromycin side effects; five required emergency department visits or hospital admission for the same. Sixteen (17%) soldiers were switched to azithromycin because of side effects; all were able to complete a 14-day course without symptoms. High adherence rates with erythromycin administration using DOP are attainable but may trigger unacceptable toxicities; alternative prophylactic regimens should be considered for active duty personnel.

Adult↗
PubMed2003

Detection of simulated candidemia by the BACTEC 9240 system with plus aerobic/F and anaerobic/F blood culture bottles.

We studied the ability of the BACTEC 9240 automated blood culture system to detect simulated candidemia, including both Candida albicans and non-albicans Candida species. Simulated blood cultures were produced using 50 Candida isolates and BACTEC Plus Aerobic/F and Anaerobic/F blood culture bottles. Ten milliliters of blood and a suspension of each isolate containing 1,000 CFU were introduced into each bottle and then incubated at 35 degrees C in the BACTEC 9240 system. The system detected growth in 56 of 100 bottles. Four isolates did not have growth detected in either bottle after 21 days of incubation, resulting in four missed episodes of candidemia. If the blood culture bottles had been incubated for 5 days, an additional episode of candidemia would have remained undetected. If the bottles had been incubated for only 3 days, another episode would have been missed, resulting in up to six missed episodes of candidemia (four Candida glabrata isolates, one C. albicans isolate, and one Candida rugosa isolate). Terminal subculture of bottles without detected growth recovered yeast in 93% (41 of 44) of the bottles, representing 41 false negatives. In bottles where growth was detected, the time to detection was approximately 24 h. However, the mean time to growth detection for C. glabrata isolates in anaerobic medium was 22.14 +/- 2.47 h, but it was 120.89 +/- 35.33 h in aerobic medium (P < 0.001). The BACTEC 9240 system detected growth of most Candida isolates; however, the delayed time to detection of C. glabrata is clinically significant. Given the high rate of false negatives, terminal subcultures may be helpful in certain situations.

Aerobiosis↗