Biomedical subjects
Publications and source records attributed to R M Massanari.
This article provides a structured review of the English literature focusing on areas that theoretically pose the greatest risk for nosocomial infections in ambulatory care. The review describes variations in methods of surveillance and a general paucity of studies that provide reliable estimates of the risk for infections in the ambulatory environment.
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There is growing demand to contain health care costs and to reassess the value of medical services. The traditional hospital, academic, and research roles of the infectious disease (ID) specialist are threatened, yet there is an increasing need for expertise because of growing antimicrobial resistance and emerging pathogens. Opportunities exist to develop and expand services for the care of patients infected with human immunodeficiency virus and in infection control, epidemiology, outcomes research, outpatient intravenous therapy, and resource management. It is important for ID physicians to appreciate the principles involved in managed care and the areas in which ID services can be valuable. To be effective, physicians need to know about tools such as practice guidelines, physician profiling, outcomes monitoring, computerized information management, risk sharing, networking, and marketing, as well as related legal issues. With a positive attitude toward learning, application, and leadership, ID physicians can redefine their role and expand their services through managed care.
We present basic information that a hospital epidemiologist needs when designing a surveillance system for noninfectious adverse outcomes of care. Specific topics reflect key characteristics of such a surveillance system: the purpose, rationale, priorities, definitions, data collection tools, data collection, analysis and reporting, and validation.
Profiling physician practice is not unfamiliar to hospital epidemiologists. Surgeon-specific postoperative wound infection rates have been used to monitor and improve the quality of surgical outcomes. However, concerns for small sample sizes, validity of methods for risk adjustment, and reliability of data collection methods along with other methodologic concerns have resulted in mixed opinions regarding physician profiling as a tool for improving quality of care. In light of pressures for healthcare reform and skepticism regarding physicians' decision making, it is unlikely that methodologic concerns will dissuade regulators and managers from expanding scrutiny of physician practice.
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A retrospective review of 766,742 hospital admissions was performed between 1966 and 1986 at the University of Iowa Hospital for the diagnosis of congenital syphilis. Although 88 individuals were identified with this diagnosis, adequate treatment was documented in only 33 (38%). Thirty-nine of the 88 individuals identified were initially seen for visual complaints by the ophthalmology department. We recommend that all physicians increase their index of suspicion for this disease, and institute appropriate therapy and follow-up if late congenital syphilis is diagnosed.
To determine the epidemiology of cytomegalovirus (CMV) infections among patients with burns, we prospectively studied 120 burn patients admitted to the University of Iowa Burn Center over a two-and-one-half year period. At the time of their admission, 44% of the patients had serologic evidence of prior CMV infection. Among 44 seropositive patients, 23 (52%) had four-fold or greater rises in CMV antibody titers. These patients had more severe burns (mean body surface area burn [BSAB] 26.8%) than those who did not exhibit titer rises (mean BSAB 16.2%, p = .04). Among 43 seronegative patients observed for at least 65 days after discharge from the center, eight (18.6%) seroconverted. Patients who seroconverted had longer hospital stays (p = .03), trends toward more severe burns (p = .08) and a younger age (p = .15) than patients who remained seronegative. Despite frequent serologic evidence of CMV infection, CMV did not contribute, either directly or indirectly, to the morbidity or mortality of burns in these patients.
A prospective double-blind trial was performed at a tertiary care center to evaluate perioperative cephalosporin prophylaxis in cardiac operations. Patients were randomized to receive either cefazolin (n = 104) or cefuroxime (n = 109), the preoperative dose being given within 1 hour before the initial incision. Drugs were continued for 48 hours (cefazolin, 1 gm intravenously every 8 hours; cefuroxime, 1.5 gm intravenously every 12 hours). Postoperative infections were assessed by trained nurse clinicians, and data were analyzed by the intention-to-treat principle. Sternal wound infections or mediastinitis occurred in one of 104 patients treated with cefazolin and 10 of 109 treated with cefuroxime (p = 0.01). Deep sternal wounds (including mediastinitis and sternal osteomyelitis) occurred in none of the cefazolin-treated patients and five cefuroxime-treated patients (p = 0.06). Although overall nosocomial infection rates were similar (16.3 versus 19.3 per 100), wound infection occurred somewhat more frequently with streptococci (groups B and D) in patients receiving cefazolin (four versus zero, p = 0.110); conversely staphylococcal infections were more frequent in the cefuroxime group (seven versus one, p = 0.066). Mean and median postoperative stay was 1 day shorter in the cefazolin group. In contrast to findings of a previous report, our data indicate that cefazolin prevented more sternal wound infections than cefuroxime, a finding that supports prophylaxis with a first-generation cephalosporin.
Determining the clinical relevance of coagulase-negative staphylococci isolated from cultures of clinical specimens remains a common dilemma. One hundred eighteen strains of coagulase-negative staphylococci isolated from patients with and without indwelling foreign bodies were characterized with regard to cell-surface hydrophobicity, slime production, and species to determine the predictive value of these phenotypic markers in distinguishing clinically significant from insignificant isolates. The single test with the highest positive predictive value was hydrophobicity (79%). Hydrophobicity and speciation had the greatest combined predictive value of any two tests (89%), and this increased to only 90% when determination of slime production was added. These tests provide additional clinical information when coagulase-negative staphylococci are isolated in culture.
Nosocomial infections reflect a dynamic interaction between host, agent, and environment. In the compromised host, the microbes most frequently associated with nosocomial infections in the ICU are bacteria that normally reside in or on body surfaces or in the environment. Infections occur when the host, compromised by the underlying disease, is exposed to a variety of diagnostic and therapeutic interventions that disrupt normal physical and chemical barriers and allow direct access to the internal milieu of the host. Efforts to prevent nosocomial infections in critical care units must take into consideration the interplay of all of these factors to be successful.
An outbreak of nosocomial aseptic meningitis involving four renal allograft recipients on the transplant service occurred in July 1986, shortly after the release of the murine monoclonal antibody OKT3 for therapy for acute allograft rejection. No bacteria, fungi, or viruses were isolated from cultures of the cerebrospinal fluid of the four patients. All four had acute allograft rejection treated with OKT3 and developed signs and/or symptoms of meningitis within 72 hours of receiving the drug. To identify potential risk factors, the four patients with aseptic meningitis were compared with 12 patients on the renal transplant service in July 1986 who did not have signs or symptoms of meningitis. The development of aseptic meningitis was strongly associated with administration of OKT3. Because of this association, prospective surveillance of meningitis in patients receiving OKT3 was instituted. From November 1986 to May 1987, three (14%) of 21 patients treated with OKT3 developed aseptic meningitis. The clinical course of aseptic meningitis associated with OKT3 appears to be benign and self-limited. Nonetheless, this observation warrants continued surveillance of OKT3 therapy.
The University of Iowa Hospitals and Clinics is located in the center of the United States in Eastern Iowa, has 1,000 hospital beds, and is the largest university owned teaching hospital in the country. Over 35,000 patients are admitted each year. The infection control efforts began in 1969 and were broadened in 1976 with the establishment and implementation of the Program of Epidemiology directed by W.J. Hierholzer, Jr., M.D., hospital epidemiologist. Hospital-wide surveillance is routinely performed by three and a half full-time equivalent LPN practitioners who assess problems and evaluate data essential to realistic identification of nosocomial infection rates, implementation of controls and evaluation of control measures. Nosocomial infection surveillance, utilizing modified CDC criteria, has been performed since July 1976. Ward rounds are made by staff, utilizing nursing care and medication Kardex's, microbiology, hematology and X-ray reports. Importantly, the surveillance system is being validated by concurrent prospective surveys to determine the sensitivity and specificity of reporting data. Outbreaks/epidemics of infections, such as Legionella pneumonia, diarrhea of unknown species, and wounds, as well as burns from manufactured changes in cautery grounds, have been identified and controlled before they have become major epidemics. Surveillance has identified one epidemic per 10,000 patients admitted.(ABSTRACT TRUNCATED AT 250 WORDS)
The macro-test for slime production by coagulase-negative staphylococci was adapted to a spectrophotometric micro-test assay to obtain more objective and quantitative information on slime production. A total of 135 isolates of coagulase-negative staphylococci (70 macro-test-positive and 65 macro-test-negative) were tested by both methods. The quantitative micro-test optical density readings were (mean +/- SD) 1.176 +/- 0.294 and 0.130 +/- 0.095 for the macro-test-positive and -negative groups, respectively. The micro-test was reproducible and demonstrated quantitative differences in slime production among the different species of coagulase-negative staphylococci. Aside from Staphylococcus epidermidis, the majority of the coagulase-negative staphylococci had very low optical density readings, indicating little or no slime production under the conditions employed in this assay. This test allows one to study the relative production of slime by different strains and species of coagulase-negative staphylococci, and may be useful in studying the effects of different conditions, such as antibiotic exposure, on slime production.
This study reports an analysis of the relative importance of laboratory antibiotic, and per diem costs of caring for 58 patients with serious Staphylococcus aureus nosocomial infections. Laboratory costs accounted for 2%, antibiotics for 21%, and per diem costs for 77% of total infection-related costs. Only 45% of patients were hospitalized for additional days specifically because of infection, but these patients stayed an average of 18 extra days. Nosocomial infections with S. aureus resistant to penicillinase-resistant penicillins (PRP) were more frequently associated with additional infection-related days of hospitalization than were PRP-susceptible infections. The cost of PRP-resistant infections was also significantly greater than PRP-susceptible infections, primarily because of the costs of additional days of hospitalization. Rational strategies to control costs of nosocomial infection should focus on two approaches: (1) prevention and (2) reduction of acute hospital days attributable to infections.
The purpose of this study was to examine the efficacy of the oxacillin disk diffusion test and the methicillin and oxacillin agar screen tests as predictors of oxacillin resistance as defined by the reference broth microdilution method. A total of 444 clinical isolates of Staphylococcus aureus collected from individual patients over a four-year period were tested by (1) the oxacillin disk diffusion test, with particular attention to the presence of fine growth of a resistant subpopulation within the zone of inhibition (Ox Grow interpretive criteria); (2) the agar screen method using agar plates with 4% NaCl and either 6 mg/L oxacillin or 10 mg/L methicillin; and (3) the oxacillin and methicillin broth microdilution test methods with 2% NaCl supplementation. Overall, 62 (14%) isolates were resistant and 382 (86%) isolates were susceptible to oxacillin with the use of the reference broth microdilution system. The results indicate that the disk diffusion test with the use of the Ox Grow criteria had a high sensitivity (94%) and negative predictive value (98%) but a low specificity (67%) and positive predictive value (32%) when compared with the reference broth dilution test. Similarly, the agar screen tests had a high sensitivity (95-97%) and negative predictive values (99%) but low specificity (64-74%) and positive predictive values (30-37%). These data indicate that the agar screen tests and the oxacillin disk test with the use of the Ox Grow interpretive criteria may be useful as screening tests for detecting resistance to the penicillinase-resistant penicillins but that all resistant isolates should be confirmed by the reference broth dilution method because of the large number of false-resistant screening test results.
Refinements in testing for resistance to penicillinase-resistant penicillins (PRP) in Staphylococcus aureus have resulted in confusion in classifying isolates as PRP susceptible or resistant. Specifically, a group of organisms has been identified that produce large amounts of beta-lactamase and appear borderline resistant. These organisms have been called "occult resistant" or "acquired oxacillin-resistant" S. aureus (AORSA). A retrospective study was conducted to evaluate the implication of this in vitro phenomenon in managing patients with AORSA infections. Among 134 patients with S. aureus infections, 89 were infected with oxacillin-susceptible S. aureus (OSSA), 26 with AORSA, and 19 with oxacillin-resistant S. aureus (ORSA). There were no significant differences in outcomes when OSSA and AORSA infections were treated with PRP (chi 2MH = .990; P = .32). These results do not suppor the contention that AORSA infections should be managed differently from OSSA infections. Identifying AORSA may not be helpful in guiding antimicrobial therapy or predicting the outcome of infections with AORSA.
A survey of 162 Veterans Administration Medical Center (VAMC) laboratories performing antimicrobial susceptibility testing was performed to determine variation in reported rates of methicillin-resistant Staphylococcus aureus (MRSA) isolation by geographic location and hospital characteristics. Of the 162 VAMC laboratories surveyed, 136 (84%) provided usable data. The percentage of S aureus isolates reported as resistant to methicillin ranged from 0% to 52% with a mean value of 10% among the 136 survey respondents. MRSA were isolated in every VA Medical District and 96% of all respondent laboratories reported isolating at least one MRSA isolate during the preceding year. These data are considered an underestimate of the time MRSA rate in the VA system due to the fact that many laboratories failed to follow key methodologic guidelines for optimal detection of MRSA. A positive correlation was found between MRSA isolation rate and several measures of hospital size and activity including total beds, total admissions, and total antimicrobial susceptibility tests performed. Geographic clustering of MRSA isolation was observed with distinct areas of very high and very low percentages of S aureus isolates reported as MRSA. The data suggest that the geographic distribution of MRSA within the VA system should be monitored closely for evidence of spread from areas with high-MRSA rates to areas of mid- or low-MRSA rates. Evidence of increased MRSA isolation within these areas may necessitate increased caution in patient referral and transfer patterns within the VA system.