Clinical Reasoning Assessment Methods: A Scoping Review and Practical Guidance

PURPOSE

An evidence-based approach to assessment is critical for ensuring the development of clinical reasoning (CR) competence. The wide array of CR assessment methods creates challenges for selecting assessments fit for the purpose; thus, a synthesis of the current evidence is needed to guide practice. A scoping review was performed to explore the existing menu of CR assessments.

METHOD

Multiple databases were searched from their inception to 2016 following PRISMA guidelines. Articles of all study design types were included if they studied a CR assessment method. The articles were sorted by assessment methods and reviewed by pairs of authors. Extracted data were used to construct descriptive appendixes, summarizing each method, including common stimuli, response formats, scoring, typical uses, validity considerations, feasibility issues, advantages, and disadvantages.

RESULTS

A total of 377 articles were included in the final synthesis. The articles broadly fell into three categories: non-workplace-based assessments (e.g., multiple-choice questions, extended matching questions, key feature examinations, script concordance tests); assessments in simulated clinical environments (objective structured clinical examinations and technology-enhanced simulation); and workplace-based assessments (e.g., direct observations, global assessments, oral case presentations, written notes). Validity considerations, feasibility issues, advantages, and disadvantages differed by method.

CONCLUSIONS

There are numerous assessment methods that align with different components of the complex construct of CR. Ensuring competency requires the development of programs of assessment that address all components of CR. Such programs are ideally constructed of complementary assessment methods to account for each method's validity and feasibility issues, advantages, and disadvantages.

Mycobacterium abscessus Complex Infections: A Retrospective Cohort Study

Background

Infections caused by Mycobacterium abscessus group strains are usually resistant to multiple antimicrobials and challenging to treat worldwide. We describe the risk factors, treatment, and clinical outcomes of patients in 2 large academic medical centers in the United States.

Methods

A retrospective cohort study of hospitalized adults with a positive culture for M. abscessus in Miami, Florida (January 1, 2011, to December 31, 2014). Demographics, comorbidities, the source of infection, antimicrobial susceptibilities, and clinical outcomes were analyzed. Early treatment failure was defined as death and/or infection relapse characterized either by persistent positive culture for M. abscessus within 12 weeks of treatment initiation and/or lack of radiographic improvement.

Results

One hundred eight patients were analyzed. The mean age was 50.81 ± 21.03 years, 57 (52.8%) were females, and 41 (38%) Hispanics. Eleven (10.2%) had end-stage renal disease, 34 (31.5%) were on immunosuppressive therapy, and 40% had chronic lung disease. Fifty-nine organisms (54.6%) were isolated in respiratory sources, 21 (19.4%) in blood, 10 (9.2%) skin and soft tissue, and 9 (8.3%) intra-abdominal. Antimicrobial susceptibility reports were available for 64 (59.3%) of the patients. Most of the isolates were susceptible to clarithromycin, amikacin, and tigecycline (93.8%, 93.8%, and 89.1%, respectively). None of the isolates were susceptible to trimethoprim/sulfamethoxazole, and only 1 (1.6%) was susceptible to ciprofloxacin. Thirty-six (33.3%) patients early failed treatment; of those, 17 (15.7%) died while hospitalized. On multivariate analysis, risk factors significantly associated with early treatment failure were disseminated infection (odds ratio [OR], 11.79; 95% confidence interval [CI], 1.53–81.69; P = .04), acute kidney injury (OR, 6.55; 95% CI, 2.4–31.25; P = .018), organ transplantation (OR, 2.37; 95% CI, 2.7–23.1; P = .005), immunosuppressive therapy (OR, 2.81; 95% CI, 1.6–21.4; P = .002), intravenous amikacin treatment (OR, 4.1; 95% CI, 0.9–21; P = .04), clarithromycin resistance (OR,79.5; 95% CI, 6.2–3717.1, P < .001), and presence of prosthetic device (OR, 5.43; 95% CI, 1.57–18.81; P = .008). Receiving macrolide treatment was found to be protective against early treatment failure (OR, 0.13; 95% CI, 0.002–1.8; P = .04).

Conclusions

Our cohort of 108 M. abscessus complex isolates in Miami, Florida, showed an in-hospital mortality of 15.7%. Most infections were respiratory. Clarithromycin and amikacin were the most likely agents to be susceptible in vitro. Resistance to fluoroquinolone and trimethoprim/sulfamethoxazole was highly common. Macrolide resistance, immunosuppression, and renal disease were significantly associated with early treatment failure.

Environmental Exposure to Carbapenem-Resistant Acinetobacter baumannii as a Risk Factor for Patient Acquisition of A. baumannii

We aimed to determine the association between environmental exposure to carbapenem-resistant Acinetobacter baumannii and the subsequent risk of acquiring this organism. Patients exposed to a contaminated hospital environment had 2.77 times the risk of acquiring carbapenem-resistant A. baumannii than did unexposed patients (relative risk, 2.77 [95% confidence interval, 1.50–5.13]; P = .002).

Acinetobacter baumannii: Association between Environmental Contamination of Patient Rooms and Occupant Status

We aimed to determine the association between the presence ofAcinetobacter baumanniiin patient rooms and the carrier status of the occupants. Fifty-six (39%) of 143 rooms withA. baumannii– positive patients had results positive forA. baumannii.Only 49 (10%) of 485 rooms withA. baumannii-negative patients were positive (odds ratio, 5.72 [95% confidence interval, 3.66–8.96];P< .0001). Clinical and environmental isolates shared pulsed-field gel electrophoresis patterns.

Decreasing Operating Room Environmental Pathogen Contamination through Improved Cleaning Practice

Objective.

Potential transmission of organisms from the environment to patients is a concern, especially in enclosed settings, such as operating rooms, in which there are multiple and frequent contacts between patients, provider's hands, and environmental surfaces. Therefore, adequate disinfection of operating rooms is essential. We aimed to determine the change in both the thoroughness of environmental cleaning and the proportion of environmental surfaces within operating rooms from which pathogenic organisms were recovered.

Design.

Prospective environmental study using feedback with UV markers and environmental cultures.

Setting.

A 1,500-bed county teaching hospital.

Participants.

Environmental service personnel, hospital administration, and medical and nursing leadership

Results.

The proportion of UV markers removed (cleaned) increased from 0.47 (284 of 600 markers; 95% confidence interval [CI], 0.42-0.53) at baseline to 0.82 (634 of 777 markers; 95% CI, 0.77-0.85) during the last month of observations (P < .0001). Nevertheless, the percentage of samples from which pathogenic organisms (gram-negative bacilli, Staphylococcus aureus, and Enterococcus species) were recovered did not change throughout our study. Pathogens were identified on 16.6% of surfaces at baseline and 12.5% of surfaces during the follow-up period (P = .998). However, the percentage of surfaces from which gram-negative bacilli were recovered decreased from 10.7% at baseline to 2.3% during the follow-up period (P = .015).

Conclusions.

Feedback using Gram staining of environmental cultures and UV markers was successful at improving the degree of cleaning in our operating rooms.

Differential environmental contamination with Acinetobacter baumannii based on the anatomic source of colonization

BACKGROUND

Acinetobacter baumannii is a pathogen of importance worldwide.

METHODS

From January 2011 until January 2012, environmental and surveillance cultures were collected from patients admitted to our intensive care units (ICUs). Surveillance cultures were obtained on admission to the ICU and weekly thereafter. Environmental cultures of high-touch surfaces were performed on an alternating basis every week. A room was designated as contaminated if at least 1 object was positive for carbapenem-resistant A baumannii. We only evaluated the rooms belonging to patients who tested positive for Acinetobacter infection.

RESULTS

Five hundred eighty-six rooms were cultured across the 5 ICUs surveyed, of which 134 (22.9%) had patients who tested positive for infection with Acinetobacter. Among patients colonized in the rectum, the odds of having bed rails contaminated with A baumannii were 2.55 times the odds of those with only respiratory colonization (P = .03). The odds of having intravenous pumps contaminated with A baumannii among patients with only respiratory colonization were 2.72 times the odds of contamination among patients colonized in the rectum (P = .03).

CONCLUSIONS

There was a significant difference in the degree of contamination of bedrails and intravenous pumps based on the occupant's anatomic source of A baumannii infection.

Control of a two-decade endemic situation with carbapenem-resistant Acinetobacter baumannii: electronic dissemination of a bundle of interventions

BACKGROUND

Our institution continued to experience a hyperendemic situation with carbapenem-resistant Acinetobacter baumannii despite a bundle of interventions. We aim to describe the effect of the subsequent implementation of electronic dissemination of the weekly findings of a bundle of interventions.

METHODS

This was a quasiexperimental study performed at a 1,500-bed, public, teaching hospital. From January 2011 to March 2012, weekly electronic communications were sent to the hospital leadership and intensive care units (ICUs). These communications aimed to describe, interpret, and package the findings of the previous week's active surveillance cultures, environmental cultures, environmental disinfection, and hand cultures. Additionally, action plans based on these findings were shared with recipients.

RESULTS

During 42 months and 1,103,900 patient-days, we detected 438 new acquisitions of carbapenem-resistant A baumannii. Hospital wide, the rate of acquisition decreased from 5.13 ± 0.39 to 1.93 ± 0.23 per 10,000 patient-days, during the baseline and postintervention periods, respectively (P < .0001). This effect was also observed in the medical and trauma ICUs, with decreased rates from 67.15 ± 10.56 to 17.4 ± 4.6 (P < .0001) and from 55.9 ± 8.95 to 14.71 ± 4.45 (P = .0004), respectively.

CONCLUSION

Weekly and systematic dissemination of the findings of a bundle of interventions was successful in decreasing the rates of carbapenem-resistant A baumannii across a large public hospital.

Interactions between anesthesiologists and the environment while providing anesthesia care in the operating room

We describe 1,132 contacts between anesthesiologists and the operating room. Objects most commonly touched included anesthesia machines and keyboards. Only 13 hand hygiene events were witnessed during 8 hours of observations. Line insertions, bronchoscopies, or blood exposures were not followed by hand hygiene. Stopcocks were accessed 66 times and only disinfected on 10 (15%) of these occasions.

Human-associated methicillin-resistant Staphylococcus aureus from a subtropical recreational marine beach

Reports of Staphylococcus aureus including methicillin-resistant S. aureus (MRSA) detected in marine environments have occurred since the early 1990 s. This investigation sought to isolate and characterize S. aureus from marine waters and sand at a subtropical recreational beach, with and without bathers present, in order to investigate possible sources and to identify the risks to bathers of exposure to these organisms. During 40 days over 17 months, 1,001 water and 36 intertidal sand samples were collected by either bathers or investigators at a subtropical recreational beach. Methicillin-sensitive S. aureus (MSSA) and MRSA were isolated and identified using selective growth media and an organism-specific molecular marker. Antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec) type, pulsed-field gel electrophoresis (PFGE) pattern, multi-locus sequence type (MLST), and staphylococcal protein A (spa) type were characterized for all MRSA. S. aureus was isolated from 248 (37 %) bather nearby water samples at a concentration range of <2-780 colony forming units per ml, 102 (31 %) ambient water samples at a concentration range of <2-260 colony forming units per ml, and 9 (25 %) sand samples. Within the sand environment, S. aureus was isolated more often from above the intertidal zone than from intermittently wet or inundated sand. A total of 1334 MSSA were isolated from 37 sampling days and 22 MRSA were isolated from ten sampling days. Seventeen of the 22 MRSA were identified by PFGE as the community-associated MRSA USA300. MRSA isolates were all SCCmec type IVa, encompassed five spa types (t008, t064, t622, t688, and t723), two MLST types (ST8 and ST5), and 21 of 22 isolates carried the genes for Panton-Valentine leukocidin. There was a correlation (r = 0.45; p = 0.05) between the daily average number of bathers and S. aureus in the water; however, no association between exposure to S. aureus in these waters and reported illness was found. This report supports the concept that humans are a potential direct source for S. aureus in marine waters.

Associations between bacterial contamination of health care workers' hands and contamination of white coats and scrubs

BACKGROUND

Uniforms are potential reservoirs for hospital organisms, potentially reinfecting the hands of health care workers (HCWs). The study aimed to determine the association between the bacterial contamination of HCWs' hands and uniforms (white coats and scrubs).

METHODS

HCWs working in 5 intensive care units had cultures obtained from their hands and uniforms (white coats or scrubs). Pathogens were defined as any gram-negative bacilli, Staphylococcus aureus, and enterococci.

RESULTS

Bacterial growth was detected on 103 hands (86%); 13 (11%) grew S aureus, 7 (6%) grew Acinetobacter spp, 2 (2%) grew enterococci, and 83 (70%) grew only skin flora. The presence of pathogens on the hands was associated with a greater likelihood of the presence of pathogens on white coats (κ = 0.81; P < .001), but not on scrubs (κ = 0.31; P = .036). Similarly, the presence of Acinetobacter on HCWs' hands was associated with a greater likelihood of Acinetobacter contamination of white coats (κ = 0.70; P < .001), but not of scrubs (κ = 0.36; P = .024).

CONCLUSIONS

Contamination of provider's hands with pathogens or Acinetobacter baumannii was associated with contamination of white coats. This association was not observed between hands and scrubs, however.

Clinical and radiological features of respiratory syncytial virus in solid organ transplant recipients: a single-center experience

BACKGROUND

Respiratory syncytial virus (RSV) infections range from upper respiratory illness to severe lower respiratory disease. There is no universally accepted treatment for RSV in solid organ transplant (SOT) recipients.

METHODS

Retrospective review of adult SOT patients with RSV infections, between January 2007 and December 2009, in a single transplant center was performed.

RESULTS

During the 3-year period, a total of 24 adults developed RSV infection, including 12 (50%) SOT recipients (5 kidneys, 4 livers, and 3 lungs). Most cases were seen in 2009 during the influenza H1N1 pandemic, likely as a result of increased testing. In 83% of the cases, the diagnosis was based on RSV antigen detection, which was also used to follow subsequent shedding (mean duration: 20.6 days). Most of the cases presented with lower respiratory disease and required hospitalization. All the patients were on at least two classes of immunosuppressive drugs. We observed a lower lymphocyte count in patients with lower respiratory tract infection. Computed tomography was superior to chest x-ray in demonstrating pulmonary disease, with the most common findings being pulmonary nodules and ground-glass opacities. Novel radiographic findings were small cavities and pleural effusions. No co-infections were documented, and no mortality could be attributed to RSV. Inhaled or oral ribavirin was administered in 67% of the cases, with variations in the treatment regimens.

CONCLUSION

SOT recipients accounted for half of all adult cases of RSV at our institution. Type and length of treatment varied widely, and we cannot conclude that outcomes differed between treatments with oral or inhaled ribavirin. Current therapeutic management of RSV in SOT is empiric, and can be rather expensive and difficult, without clear evidence of effectiveness.

Successful eradication of a monoclonal strain of Klebsiella pneumoniae during a K. pneumoniae carbapenemase-producing K. pneumoniae outbreak in a surgical intensive care unit in Miami, Florida

We describe the investigation and control of a Klebsiella pneumoniae carbapenemase-producing K. pneumoniae outbreak in a 20-bed surgical intensive care unit during the period from January 1, 2009 through January 1, 2010. Nine patients were either colonized or infected with a monoclonal strain of K. pneumoniae. The implementation of a bundle of interventions on July 2009 successfully controlled the further horizontal spread of this organism.

Candida glabrata infection in gastric carcinoma patient mimicking cutaneous histoplasmosis

Candida glabrata is the second most common Candida species detected among hospitalized patients in USA. In tissue C. glabrata present as yeasts, 3-5 microns in size, which are difficult to visualize on H&E stained slides but can be detected on Grocott methenamine silver (GMS) stained slides. The presence of yeasts only, without any hyphal elements, makes C. glabrata difficult to distinguish from Histoplasma capsulatum yeasts that are of similar size. Mycology culture is the method of choice for definitive identification of C. glabrata. Rapid identification is necessary, as mortality rate due to C. glabrata infection in immunocompromised patients is particularly high. We herein report a patient with inoperable gastric carcinoma, who developed cutaneous and septic form of C. glabrata infection.

Differences in presentation and outcome of invasive pneumococcal disease among patients with and without HIV infection in the pre-HAART era

Invasive pneumococcal disease (PD) occurs frequently among HIV-infected patients, but it is unclear whether its manifestations and outcome are different compared to those observed among patients without HIV-1 infection. Because the immune reconstitution that accompanies antiretroviral therapy may change some of these features and because most cases of HIV- 1 infection occur in resource-poor settings of the world where access to antiretroviral agents is limited, we compared PD among patients with and without HIV-1 infection in a North American population before the introduction of highly active antiretroviral therapy (HAART). The records of all pneumococcal cultures processed at this medical center over a period of 20 months were used to identify patients with invasive PD. Hospital records were reviewed for 103 of these patients (52 with and 51 without HIV-1 infection) and demographic, clinical, laboratory, radiographic, and microbiologic information was abstracted and subsequently analyzed. Despite similarities in presenting signs and symptoms, we found a higher incidence of bacteremia but a more favorable outcome with less frequent requirements for intubation and admission to intensive care units and better survival among individuals with HIV infection. Factors such as less advanced age, the presence of fewer comorbid conditions, or a less florid inflammatory response among HIV-infected individuals may account for differences in outcome of invasive PD.

Multidrug-resistant tuberculous meningitis in patients with AIDS

We present clinical manifestations, bacteriologic characteristics, and outcomes for eight patients with multidrug-resistant (MDR) tuberculous meningitis and AIDS. All developed meningitis as a terminal complication of previously diagnosed MDR-TB despite anti-tuberculosis therapy. Seven patients presented with fever, five with headache, four with altered mentation, two with focal deficits and one with seizures. CSF examination revealed pleocytosis, hypoglychorrhachia and elevated protein. Mycobacterium tuberculosis resistant to at least isoniazid and rifampin was isolated from all patients. Intracerebral mass lesions were detected in three patients, hydrocephalus in three, meningeal enhancement in five, and infarcts in two. Seven patients died 1-16 weeks after the diagnosis of meningitis; the eighth was lost to follow-up. MDR tuberculous meningitis is a difficult-to-treat infection with a high fatality rate.

Rapid and specific detection of the Mycobacterium tuberculosis complex using fluorogenic probes andreal-time PCR

A rapid and sensitive strategy for the specific identification of Mycobacterium tuberculosis (TB) was designed and evaluated using crude mycobacterial lysates. The speed of real-time polymerase chain reaction (PCR) was combined with the sensitivity of fluorogenic probes to confirm the presence of mycobacteria as well as specifically identify the presence of members of the mycobacteria tuberculosis complex (MTC) in a single-tube assay. Oligonucleotides were designed to amplify the internal transcribed spacer (ITS) from several mycobacterial species. Specific fluorogenic probes were included in the PCR reaction for the identification of TB as well as Mycobacterium bovia and Mycobacterium africanum in bacterial lysates. The combination of TB-specific fluorogenic probes with real-time PCR formed an approach determined to be fast (less than 40 min), sensitive (less than 800 copies of DNA) and reliable for the specific detection of the MTC. Our data demonstrate the use of real-time PCR and fluorogenic probes in a rapid and sensitive assay to distinguish members of the MTC from other mycobacterial species.

Cerebral phaeohyphomycosis due to a novel species: report of a case and review of the literature

Cerebral phaeohyphomycosis is a rare disease caused by dematiaceous (darkly pigmented) fungi. Cladophialophora species are highly neurotropic, and Cladophialophora bantiana (synonym=Xylohypha bantiana or C. trichoides) is the most commonly identified agent. Most reported cases of cerebral phaeohyphomycosis have occurred in immunocompetent patients; however, some case reports and experimental data have suggested that cellular immune deficiency is a risk factor. We report a case of pulmonary and cerebral phaeohyphomycosis in a cardiac transplant patient due to a newly identified species of Cladophialophora. Optimal management includes both antifungal therapy and surgery.

Evaluation of the LiPA MYCOBACTERIA assay for identification of mycobacterial species from BACTEC 12B bottles

The LiPA MYCOBACTERIA (Innogenetics NV, Ghent, Belgium) assay was used to identify mycobacterial isolates using culture fluid from positive BACTEC 12B bottles. The LiPA method involves reverse hybridization of a biotinylated mycobacterial PCR fragment, a 16 to 23S rRNA spacer region, to oligonucleotide probes arranged in lines on a membrane strip, with detection via biotin-streptavidin coupling by a colorimetric system. This system identifies Mycobacterium species and differentiates M. tuberculosis complex, M. avium-M. intracellulare complex, and the following mycobacterial species: M. avium, M. intracellulare, M. kansasii, M. chelonae group, M. gordonae, M. xenopi, and M. scrofulaceum. The mycobacteria were identified in the laboratory by a series of tests, including the Roche AMPLICOR Mycobacterium tuberculosis (MTB) test, the Gen-Probe ACCUPROBE, and a PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the 65-kDa heat shock protein gene. The LiPA MYCOBACTERIA assay detected 60 mycobacterium isolates from 59 patients. There was complete agreement between LiPA and the laboratory identification tests for 26 M. tuberculosis complex, 9 M. avium, 3 M. intracellulare complex, 3 M. kansasii, 4 M. gordonae, and 5 M. chelonae group (all were M. abscessus) isolates. Three patient samples were LiPA positive for M. avium-M. intracellulare complex, and all were identified as M. intracellulare by the PCR-RFLP analysis. Seven additional mycobacterial species were LiPA positive for Mycobacterium spp. (six were M. fortuitum, and one was M. szulgai). The LiPA MYCOBACTERIA assay was easy to perform, and the interpretation of the positive bands was clear-cut. Following PCR amplification and gel electrophoresis, the LiPA assay was completed within 3 h.

Disseminated miliary tuberculosis of the skin in patients with AIDS: report of four cases

We present clinical, bacteriologic, and pathological findings for four patients with AIDS and cutaneous miliary tuberculosis. All patients had generalized tuberculosis with hematogenous dissemination to multiple organs including the skin. Microscopic examination of the skin lesions revealed ill-formed or no granulomata, extensive necrosis, and numerous acid-fast bacilli. Mycobacterium tuberculosis was detected in the skin lesions by cultures for three patients and by polymerase chain reaction for one. Three of the isolates were resistant to at least isoniazid and rifampin, and one was susceptible to these drugs. The outcome was rapidly fatal for the three patients with multidrug-resistant tuberculosis. This report draws attention to the reappearance of a once-rare manifestation of disseminated tuberculosis which, in the setting of advanced human immunodeficiency virus disease, may offer the first indication of infection with multidrug-resistant M. tuberculosis and a poor prognosis.

Human T lymphocyte subpopulation and NK cell alterations in persons exposed to cocaine

Immunophenotypic changes in peripheral blood mononuclear cells were analyzed by flow cytometry in several patient groups positive for cocaine in their urine. Single- and dual-color immunofluorescence staining was performed to examine total numbers of NK, T, and B cells, as well as the coexpression of surface molecules on T cells associated with memory function, helper/inducer capacity, and activation status. In addition, levels of several serum proteins (including immunoglobulins) and other demographic variables were evaluated. Our results show that cocaine-intoxicated patients display reductions in the total percentage of CD4+ T cells and increases in the number of NK cells. Dramatic shifts within certain T cell subpopulations were also observed. In particular, there appeared to be a preferential stimulation of "activated" T cells as indicated by increased levels of class II+ CD4 and CD8 T cells and IL2r+ CD4 T cells. "Memory" CD8+ T cell subpopulations (i.e., CD45RO+) were reduced in the cocaine-positive patients, whereas CD45R+/CD8+ T cells were accordingly increased in the same individuals. In some cases, direct correlation could be established between certain T cell percentages and cocaine levels. None of the serum protein levels measured appeared to be influenced by cocaine. These findings demonstrate that cocaine utilization is associated with variations in levels of certain T cell subpopulations and other immune cells. This may represent a disruption of particular immunologic cell networks which could ultimately influence host resistance to infection and malignancy.

Evaluation of a mannitol-salt-oxacillin-tellurite medium for the isolation of methicillin-resistant Staphylococcus aureus from contaminated sources

A mannitol-salt medium supplemented with 0.002% tellurite (MSOT) supported the growth of 104 of 109 strains of methicillin-resistant Staphylococcus aureus (MRSA) while suppressing 74 of 102 strains of mannitol-positive, methicillin-resistant coagulase-negative staphylococci. MSOT was equally or more sensitive and more differential than a similar formulation without tellurite for the isolation of MRSA from the skin and nares of hospitalized patients. Only S. haemolyticus produced dark gray-to-black colonies on MSOT similar to those of MRSA. MSOT is a useful adjunct to other nonselective culture formulations for the isolation of MRSA from contaminated sources.

Detection of herpes viral genomes in normal and diseased corneal epithelium

Herpetic ocular disease is one of the major causes of corneal blindness. Clinical diagnosis of corneal disease is based principally on corneal appearance. However, abnormal morphology of the corneal epithelium (CE) is not an indicator for the presence of a herpes virus. Further, it has not been established if herpes viruses are present in normal corneal epithelial tissue. In these studies, the polymerase chain reaction was used to evaluate normal and diseased corneal epithelium for the presence of herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) genomic sequences. Thirty-two normal corneal epithelium specimens obtained from cadavers shortly after death were analyzed for HSV-1, EBV and CMV genomic sequences. Three of the 32 normal CE specimens were positive for amplified EBV DNA, 1 was positive for HSV-1 DNA, and none was positive for CMV DNA. We also tested eight herpetic dendritic lesions of which 3 were HSV-1 culture and PCR positive. The remaining five dendritic lesions were HSV-1 culture and PCR negative. Since these lesions were not evaluated for other herpesviruses, the etiology of these dendritic lesions is unknown. Six corneal epithelium samples from HIV-infected donors were negative for EBV, CMV and HSV-1 amplified sequences. Positive EBV, CMV and HSV-1 serology on all normal donors and on donors with clinically apparent disease did not correlate with positive PCR results. The results of these studies suggest that EBV and HSV-1 DNA can be amplified from a small percentage of apparently normal corneal epithelium.

The antimicrobial susceptibility patterns of the Bacteroides fragilis group in the United States, 1987

A nationwide survey to monitor the susceptibility of the Bacteroides fragilis group, which began in 1981, was continued during 1987. In addition to the eleven drugs evaluated in 1986, sulbactam, a potent beta-lactamase inhibitor, was tested alone and in combination with ampicillin and cefoperazone. Imipenem, ampicillin/sulbactam, cefoperazone/sulbactam, and ticarcillin/clavulanic acid were the most active newer drugs tested, with less than 1% resistance rates. Chloramphenicol, metronidazole and clindamycin also had excellent activity with resistance rates of 0%, 0%, and 3% respectively. Resistance rates to cefoxitin remained stable at 8%. Ceftizoxime and cefotetan had resistance rates of 26% and 29%, respectively. Rates of resistance varied among different institutions and between the various species.

Detection of Epstein-Barr virus genomes in normal human lacrimal glands

Epstein-Barr virus (EBV) has been implicated in several ocular diseases; however, detection of the EBV genome in ocular tissues has not been documented. We report the detection of amplified EBV genomic sequences in 11 of 26 normal lacrimal gland DNA samples by using the polymerase chain reaction. Serum was available for 19 of the lacrimal gland donors. All 19 were EBV seropositive, although of the 19 lacrimal gland-seropositive patients, EBV sequences were detected in only 10 of the samples. Further, amplified EBV sequences were not detected in circulating lymphocyte DNA from normal seropositive volunteers, most likely because of the low frequency of circulating EBV-infected B cells. Amplification of EBV from cadaver lacrimal gland DNA was possible with minute quantities of DNA, whereas peripheral blood mononuclear cell DNA from normal volunteers did not amplify EBV sequences. Interestingly, the peripheral blood mononuclear cell polymerase chain reactions contained approximately 100 times more DNA than the lacrimal gland polymerase chain reactions. We conclude that the lacrimal gland may be a site for EBV persistence and that positive EBV serology is not an indicator of which individuals may have EBV harbored within their lacrimal glands.

Comparative activities of newer beta-lactam agents against members of the Bacteroides fragilis group

A nationwide susceptibility survey of 557 isolates of the Bacteroides fragilis group was continued in 1986. The most active beta-lactam drugs were imipenem and ticarcillin-clavulanic acid, which had 0.2 and 1.7% resistance, respectively. The rank order of activity of beta-lactam drugs was imipenem, ticarcillin-clavulanic acid, cefoxitin, piperacillin, moxalactam, ceftizoxime, cefotetan, cefotaxime, cefoperazone, and ceftazadime.

Mycoplasma hominis septic thrombophlebitis in a patient with multiple trauma: a case report and literature review

Mycoplasma hominis was recovered from the site of a septic thrombophlebitis on the left cephalic veins of a patient with pelvic and other multiple trauma. The organisms were initially isolated from routine cultures in conventional blood agar media incubated anaerobically. The absence of other demonstrable pathogens and the patient's serologic response to the isolate support the role of the organism as the cause of this previously unreported mycoplasmal infection. M. hominis should be considered a possible cause of sepsis in selected cases of infections following pelvic trauma or manipulations of the genitourinary tract.

Susceptibility of the Bacteroides fragilis group in the United States: analysis by site of isolation

An ongoing survey of the susceptibility of the Bacteroides fragilis group of bacteria was continued at New England Medical Center in 1984 and 1985. A total of 1,229 strains were obtained from eight centers in the United States. These results were compared with those for 1,847 isolates tested in 1981 through 1983. The most active beta-lactam drugs were imipenem and ticarcillin-clavulanic acid (Timentin), which had a less than 1% resistance rate. No metronidazole- or chloramphenicol-resistant isolates were found during the 5 years of the study. Isolates obtained from blood, perinatal, and bone sites of infection were more resistant to a variety of antimicrobial agents. Susceptibility patterns of the members of the B. fragilis group varied at the eight hospitals and among species. These data indicate the need for determining the susceptibility patterns for the B. fragilis group of organisms at each hospital.

Tuberculosis and nontuberculous mycobacteriosis in patients with AIDS

Thirty-six patients with AIDS and culture-proven nontuberculous mycobacteriosis were compared to 20 patients with acquired immunodeficiency syndrome (AIDS) and tuberculosis with regard to clinical signs, symptoms, and diagnostic methods. Patients with nontuberculous mycobacteriosis were more often younger and homosexuals, while patients with tuberculosis were usually Haitian-American or users of intravenous drugs. A majority of patients with tuberculosis presented with fever and weight loss. These symptoms were seen in approximately 50 percent of the patients with nontuberculous mycobacteriosis. A distinct syndrome of dyspnea, chills, hemoptysis, and chest pain was seen in a significant minority of patients with nontuberculous mycobacteriosis. Lymphadenopathy was seen almost exclusively in patients with tuberculosis. Pulmonary sources (expectorated sputum or bronchoscopy specimens) were the most common source of diagnosis in both groups. Patients in both groups in whom the diagnosis was obtained from pulmonary sources frequently had negative chest x-ray films on presentation. Cavitary disease was absent from both groups.

Nationwide study of the susceptibility of the Bacteroides fragilis group in the United States

A nationwide susceptibility survey of the Bacteroides fragilis group was continued at New England Medical Center in 1983. A total of 555 strains were obtained from eight centers in the United States. In addition to the nine antimicrobial agents studied in the two previous years, three other agents were added to the evaluation: cefamandole, cefuroxime, and cefonicid. The results for the strains tested with the original nine drugs in 1983 were compared with those for 1,292 isolates tested in 1981 and 1982. The most active beta-lactam drug was piperacillin, which had an 8% resistance rate. Cefoxitin resistance increased from 10% in 1982 to 16% in 1983. High rates of resistance to cefotaxime, cefoperazone, cefamandole, cefonicid, and cefuroxime were encountered. No metronidazole- or chloramphenicol-resistant isolates were found during the 3 years of the study. Susceptibility patterns varied at the eight hospitals: the outbreak of cefoxitin resistance reported in 1982 at New England Medical Center remitted, while a high clindamycin resistance rate was documented at one hospital in 1983. These data indicate the need for determining the susceptibility patterns for the B. fragilis group of organisms at each hospital.

Antimicrobial susceptibilities of 1,292 isolates of the Bacteroides fragilis group in the United States: comparison of 1981 with 1982

A susceptibility survey of 537 strains of the Bacteroides fragilis group from eight centers in the United States was continued at the Tufts New England Medical Center in 1982. The results were compared with those of 755 organisms analyzed in 1981. Nine antimicrobial agents were tested by an agar dilution method. The respective percentages of resistance for 1981 and 1982 were as follows (%): cefoxitin, 8 and 10; moxalactam, 22 and 12; cefotaxime, 54 and 48; cefoperazone, 57 and 54; piperacillin, 12 and 7; clindamycin, 6 and 3; metronidazole, 0 and 0; chloramphenicol, 0 and 0; and tetracycline, 63 and 59. Regional differences in resistance rates were found. Declines in resistance to moxalactam, piperacillin, and clindamycin were noted at the participating hospitals. An outbreak of cefoxitin resistance was noted at the Tufts New England Medical Center, where the rate increased from 14 to 30%. The various species of the B. fragilis group had differing patterns of resistance; B. fragilis was the most susceptible species. Significant cross resistance among the beta-lactam agents was found. These data indicate the need to determine the susceptibility patterns of the B. fragilis group organisms within each hospital.

Surveillance study of pediatric patients receiving respiratory therapy, using the Bain circuit system

The Bain circuit, which has been used previously for anesthesia, was adopted for long-term mechanical ventilation for infants and children in a pediatric intensive care unit. When this ventilation system is used, humidifier temperatures must be kept at temperatures significantly lower than the recommended 50 degrees C to avoid excessive airway temperatures and thermal injury. Routine infection control measures such as daily changing of respiratory therapy equipment and the use of sterile water in Cascade humidifiers were enforced. It was demonstrated that the use of the Bain circuit with a Cascade humidifier kept at a temperature of 36.9 degrees +/- 1.9 degrees C was not associated with nosocomial infection of the lower respiratory tract.

Quantitation of Candida albicans polysaccharide using an enzyme-linked immunosorbent assay

The enzyme-linked immunosorbent assay (ELISA) for candida polysaccharide antigen in serum was developed by using double antibody sandwich technique. It was found that serum constituents substantially interfered with the assay. The interference was successfully decreased by heating serum in the presence of EDTA which precipitated interfering serum protein. In addition, candida antigen may be liberated from antibody complexes. The candida polysaccharide antigen in the supernatant was precipitated with ethanol and resuspended in the buffer containing gelatin. A maximum sensitivity of 10 ng/ml was found in the assay using this procedure. This procedure of serum treatment may have potential applications for the detection of other polysaccharide antigens in serum.

Multiple-dose amikacin kinetics in pediatric oncology patients

Amikacin kinetics was studied in 8 pediatric oncology patients who received the drug by intravenous infusion over 30 or 60 min at a dose of 5 mg/kg every 6 or 8 hr. This regimen is recommended but, due to patient variability, patients should be monitored. Dosing intervals during 1 or 2 and 3 or 4 days of therapy were studied with serum samples collected before and at the end of the infusion and serially to the end of the dosing interval. The data appeared consistent with and were analyzed according to 1-compartment model. An equation describing serum concentration with time for the multiple-dose case was fit to each patient's multiple-interval data with nonlinear regression. Half-life averaged 1.2 hr. volume of distribution 0.24 l/kg, and total body clearance 109 ml/min/1.73 m2 or 2.51 ml/min/kg. The volume of distribution and the clearance are greater than reported for adults and probably account for the larger dose needed to achieve and maintain therapeutic levels. Although the total daily dose was greater than previously reported, there were no signs of toxicity, although therapuetic concentrations were maintained.

Enzyme immunoassay of hepatitis associated antigen (HAA)

Due to its high sensitivity, radioimmunoassay has become of great importance in the detection and measurement of levels of proteins and steroids in body fluids. However, this method involves the use of expensive equipment and radioactive material. Herein is described an alternate method to radioimmunoassay, which uses an enzyme-labeled rather than a radioactively-labeled antibody. An enzyme immunoassay procedure, the Cordia HAA-enzyme Immunoassay, for the detection of hepatitis-associated antigen has been evaluated. With this technique a sandwich type immunoassay with an alkaline phosphatase tagged second antibody is used. The presence of antigen is detected by the p-nitrophenyl phosphotase activity of the bound enzyme. In 1083 clinical samples from patients of Jackson Memorial Hospital, only 19 discrepant results were found when tested by both the Cordia and the Ausria II methods. Eight had sufficient sera for retesting, yielding two positive Cordia, negative Austia; one negative Cordia, positive Ausria; one borderline positive; and four unconfirmed false positives by Cordia.