Mixed infection involving Actinomyces, Aggregatibacter, and Fusobacterium species presenting as perispinal tumor.

A representative case in which a polymicrobial infection involving Fusobacterium nucleatum, Actinomyces israelii and Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans was initially diagnosed as malignancy in an edentulous patient. Additional history obtained after the nature of the syndrome was elucidated revealed that he had had his two remaining teeth extracted four months prior to this episode.

Trends in invasive disease due to Candida species following heart and lung transplantation.

Although invasive candidiasis (IC) causes significant morbidity and mortality in patients who undergo heart, lung, or heart-lung transplantation, a systematic study in a large cohort of thoracic organ transplant recipients has not been reported to date. Clinical and microbiological data were reviewed for 1305 patients who underwent thoracic organ transplantation at Stanford University Medical Center between 1980 and 2004. We identified and analyzed 76 episodes of IC in 68 patients (overall incidence 5.2% per patient).The incidence of IC was higher in lung (LTx) and heart-lung transplant (HLTx) recipients as compared with heart transplant (HTx) recipients (risk ratio [RR] 1.7, 95% confidence interval [CI] 1.1-2.7).The incidence of IC decreased over time in all thoracic organ transplant recipients, decreasing from 6.1% in the 1980-1986 time period to 2.1% in the 2001-2004 era in the HTx recipients, and from 20% in the 1980-1986 period to 1.8% in the 2001-2004 period in the LTx and HLTx recipients.The most common site of infection differed between the HTx and LTx cohorts, with bloodstream or disseminated disease in the former and tracheobronchitis in the latter. IC in the first year after transplant was significantly associated with death in both HTx (RR 2.9, 95% CI 1.8-4.6, P=0.001) and LTx and HLTx patients (RR 3.0, 95% CI 1.9-4.6, P<0.001). The attributable mortality from IC decreased during the 25-year period of observation, from 36% to 20% in the HTx recipients and from 39% to 15% in the LTx and HLTx recipients. There were a significant number of cases caused by non-albicans Candida species in all patients, with a trend toward higher mortality in the HTx group. In conclusion, the incidence and attributable mortality of IC in thoracic organ transplant recipients has significantly declined over the past 25 years.The use of newer antifungal agents for prophylaxis and treatment, the decrease in the incidence of cytomegalovirus disease, and the use of more selective immunosuppression, among other factors, may have been responsible for this change.

Characterization of Salmonella enterica serotype newport isolated from humans and food animals.

Salmonella enterica serotype Newport isolates resistant to at least nine antimicrobials (including extended-spectrum cephalosporins), known as serotype Newport MDR-AmpC isolates, have been rapidly emerging as pathogens in both animals and humans throughout the United States. Resistance to extended-spectrum cephalosporins is associated with clinical failures, including death, in patients with systemic infections. In this study, 87 Salmonella serotype Newport strains were characterized by pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing and examined for the presence of class 1 integrons and bla(CMY) genes. Thirty-five PFGE patterns were observed with XbaI, and three of these patterns were indistinguishable among isolates from humans and animals. Fifty-three (60%) Salmonella serotype Newport isolates were identified as serotype Newport MDR-AmpC, including 16 (53%) of 30 human isolates, 27 (93%) of 29 cattle isolates, 7 (70%) of 10 swine isolates, and 3 (30%) of 10 chicken isolates. However, 28 (32%) Salmonella serotype Newport isolates were susceptible to all 16 antimicrobials tested. The bla(CMY) gene was present in all serotype Newport MDR-AmpC isolates. Furthermore, the plasmid-mediated bla(CMY) gene was transferable via conjugation to an Escherichia coli strain. The transconjugant showed the MDR-AmpC resistance profile. Thirty-five (40%) of the isolates possessed class 1 integrons. Sequence analyses of the integrons showed that they contained aadA, which confers resistance to streptomycin, or aadA and dhfr, which confer resistance to trimethoprim-sulfamethoxazole. One integron from a swine isolate contained the sat-1 gene, which encodes resistance to streptothricin, an antimicrobial agent that has never been approved for use in the United States. In conclusion, Salmonella serotype Newport MDR-AmpC was commonly identified among Salmonella serotype Newport isolates recovered from humans and food animals. These findings support the possibility of transmission of this organism to humans through the food chain.

Rapid identification of bacteria and yeast: summary of a National Committee for Clinical Laboratory Standards proposed guideline.

Using colony morphology on selected agars, Gram-stain morphology, and a number of 1-step biochemical or enzymatic tests, skilled microbiologists can identify the species of the majority of isolates seen routinely in a clinical laboratory. These results are often available more quickly than and are as accurate as those derived from conventional methods. The National Committee for Clinical Laboratory Standards has produced a guideline that describes tests that can be used to identify a number of aerobic gram-negative rods and gram-positive cocci, a number of commonly isolated anaerobes, and 3 species of yeast. An overview of the organisms included in the guideline, the tests that identify them, and the situations in which rapid testing is appropriate is presented here.

Role of clinical microbiology laboratories in the management and control of infectious diseases and the delivery of health care.

Modern medicine has led to dramatic changes in infectious diseases practice. Vaccination and antibiotic therapy have benefited millions of persons. However, constrained resources now threaten our ability to adequately manage threats of infectious diseases by placing clinical microbiology services and expertise distant from the patient and their infectious diseases physician. Continuing in such a direction threatens quality of laboratory results, timeliness of diagnosis, appropriateness of treatment, effective communication, reduction of health care-associated infections, advances in infectious diseases practice, and training of future practitioners. Microbiology laboratories are the first lines of defense for detection of new antibiotic resistance, outbreaks of foodborne infection, and a possible bioterrorism event. Maintaining high-quality clinical microbiology laboratories on the site of the institution that they serve is the current best approach for managing today's problems of emerging infectious diseases and antimicrobial agent resistance by providing good patient care outcomes that actually save money.

Fecal leukocyte stain has diagnostic value for outpatients but not inpatients.

The methylene blue stain for fecal leukocytes (FL) is widely used as an adjunct to slower but more accurate tests of diarrheal etiology, such as stool culture (SCx) or toxin assays for Clostridium difficile. Prior studies investigating the utility of FL for predicting SCx and C. difficile toxin assay (CDTA) results did not evaluate the importance of inpatient versus outpatient status. We conducted a study of patients who submitted a stool specimen to the Stanford Hospital Microbiology Laboratory between May 1998 and April 1999. The results for stool specimens that were tested by FL and by a confirmatory test (either SCx or CDTA) were used to determine whether the FL method helped to predict the results of these tests. Of 797 stools that were tested by FL method and at least one confirmatory test, 502 stools were tested by CDTA, and 473 stools were cultured. The FL test was 14% sensitive and 90% specific for C. difficile with a diagnostic threshold of one white blood cell/high-power field (WBC/HPF). The overall likelihood ratio (LR) for a positive CDTA was 1.4 with a 95% confidence interval (CI) of 0. 5 to 3.7 (P = 0.5) and was similar among inpatients and outpatients. In contrast, the presence of >/=1 WBC/HPF was 52% sensitive and 88% specific for the 27 positive SCx results and helped to predict a positive SCx result (LR, 4.2; 95% CI, 2.7 to 6.5; P < 0.001). The sensitivity of >/=1 WBC/HPF was 57%, and its predictive value for SCx was higher among outpatients (outpatient LR, 5.0; 95% CI, 2.9 to 8.6; P < 0.001; inpatient LR, 1.9; 95% CI, 0.3 to 10.8; P = 0.5). Among inpatients, only 4 (1.5%) of the 273 SCx results were positive, and the presence of >/=1 WBC/HPF was insensitive (25%) and did not predict a positive SCx (LR, 1.9; 95% CI, 0.3 to 10.8; P = 0.5). When the data were reanalyzed using a diagnostic threshold of five WBC/HPF for FL, the predictive power of the FL method was similar. Thus, FL was of no value in predicting CDTA positivity, nor was it helpful in predicting SCx results for inpatients. Neither SCx nor the FL method should routinely be performed on samples from inpatients. Among outpatients, presence of FLs should suggest a bacterial diarrhea in clinically compatible cases.

Multilaboratory validation of rapid spot tests for identification of Escherichia coli.

To validate the accuracy of rapid tests for identification of Escherichia coli, five laboratories sequentially collected 1,064 fresh, clinically significant strains with core criteria of indole-positive, oxidase-negative, nonspreading organisms on sheep blood agar plates (BAP), having typical gram-negative rod plate morphology, defined as good growth on gram-negative rod-selective media. An algorithm using beta-hemolysis on BAP, lactose reaction on eosin-methylene blue or MacConkey agar, L-pyrrolidonyl-beta-naphthylamide (PYR), and 4-methylumbelliferyl-beta-D-glucuronide (MUG) was evaluated. Identifications using the algorithm were compared to those obtained using commercial kit system identifications. One thousand strains were E. coli and 64 were not E. coli by kit identifications, which were supplemented with conventional biochemical testing of low probability profiles. Of the 1,064 isolates meeting the core criteria, 294 were beta-hemolytic and did not require further testing to be identified as E. coli. None of the 64 non-E. coli strains were hemolytic, although other indole-positive, lactose-negative species were found to be hemolytic when further strains were examined in a follow-up study. Of the remaining strains, 628 were identified as E. coli by a lactose-positive and PYR-negative reaction. For nonhemolytic, lactose-negative E. coli, PYR was not helpful, but a positive MUG reaction identified 65 of 78 isolates as E. coli. The remaining 13 E. coli strains required kit identifications. This scheme for E. coli identification misidentified three non-E. coli strains as E. coli, for an error rate of 0.3%. A total of 13 kit identifications, 657 PYR tests, and 113 MUG tests were needed to identify 1,000 E. coli strains with the algorithm. The use of this rapid system saves laboratory resources, provides timely identifications, and yields rare misidentifications.

Methicillin-resistant Staphylococcus aureus outbreak: a consensus panel's definition and management guidelines.

OBJECTIVE: To provide medical personnel with a definition of an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) and guidelines for managing potential outbreaks. PARTICIPANTS: Eighteen panel members were chosen from different specialties, types of institutions, and geographic regions. Representatives from the American Society of Consultant Pharmacists, the American Society of Health-Systems Pharmacists, the Society for Healthcare Epidemiology of America, and the National Association of Directors of Nursing Administration participated. CONSENSUS PROCESS: In preparation for the conference, panel members reviewed the literature and wrote abstracts outlining their personal opinions on the core issues, which were circulated to all participants. During a weekend conference, the panel summarized the reviewed literature, defined an MRSA outbreak, and developed management guidelines. EVIDENCE: Published literature, clinical experience, and expert opinion concerning the emergence and subsequent management of MRSA cases in health care institutions. RESULTS: An outbreak of MRSA was defined as either an increase in the rate of MRSA cases or a clustering of new cases due to the transmission of a single microbial strain in the health care institution. An increased rate of cases can be defined statistically or experientially and includes both infected and colonized patients. A potential outbreak should trigger stepwise, multidisciplinary actions consisting of basic epidemiologic procedures (phase I) to form an initial epidemiologic hypothesis of an outbreak (phase II) followed by a standard epidemiologic workup (phase III) and microbiologic studies (phase IV) to confirm the hypothesis. Mupirocin calcium treatments should be considered to decolonize health care workers during the fourth phase, even before typing is completed. CONCLUSIONS: Until studies can be conducted to delineate the effectiveness of different recommendations, the proposed guidelines may provide a useful starting point that can be adapted to meet an individual institution's specific needs.

Bilophila wadsworthia: a unique Gram-negative anaerobic rod.

Although comprising less than 0.01% of the normal human gastrointestinal microbiota, Bilophila wadsworthia is the third most common anaerobe recovered from clinical material obtained from patients with perforated and gangrenous appendicitis. Since its discovery in 1988, B. wadsworthia has been recovered from clinical specimens associated with a variety of infections, including sepsis, liver abscesses, cholecystitis, Fournier's gangrene, soft tissue abscesses, empyema, osteomyelitis, Bartholinitis, and hidradenitis suppurativa. In addition, it has been found in the saliva and vaginal fluids of asymptomatic adults and even in the periodontal pockets of dogs. The organism is a saccharolytic, fastidious, and is easily recognized by its strong catalase reaction with 15% H2O2, production of hydrogen sulfide, and growth stimulation by bile (oxgall) and pyruvate. Approximately 75% of strains are urease positive. When grown on pyruvate-containing media, > 85% of strains demonstrate beta-lactamase production. Ribosomal RNA-based phylogenetic studies show Bilophila to be a homogeneous species, most closely related to Desulfovibrio species. Both adherence to human cells and endotoxin have been observed, and preliminary work suggests that environmental iron has a role in expression of outer membrane proteins. Penicillin-binding proteins appear to mediate the organism's susceptibility to at least some beta-lactam agents, which induce spheroplast formation that results in a haze of growth on agar dilution susceptibility test plates which is difficult to interpret. Bilophilastrains are inhibited in vitro by most antibiotics.

Lack of agreement among two commercial enzyme-linked immunosorbent antibody assays and a conventional immunofluorescence-based method for detecting islet cell autoantibodies.

Two commercial enzyme-linked immunosorbent assays (ELISAs) for antibodies associated with development of insulin-dependent (type 1) diabetes mellitus (IDDM) were evaluated in conjunction with a conventional indirect immunofluorescent-antibody-islet cell antibody (ICA) test and a radioimmunoprecipitation method for detection of insulin autoantibodies in sera from a selected group of patients. The anti-ICA ELISA was positive for only 1 to 17 serum samples from newly diagnosed IDDM patients but yielded false-positive results with 2 of 6 serum samples containing non-diabetes-related autoantibodies. Although the anti-glutamic acid decarboxylase ELISA did not show positive results for sera with other autoantibodies, it was positive for only 4 of 29 serum samples from recently diagnosed IDDM patients and for 49% of 37 indirect immunofluorescent-antibody-ICA test-positive sera. Until the antibodies associated with the development of diabetes are better characterized, allowing better standards for comparison, it will be difficult to evaluate commercial assays in this field.

Infectious disease physicians rate microbiology services and practices.

Recent years have seen increasing emphasis on cost containment and quality improvement in clinical laboratory activities. Modifying those activities to enhance clinical relevance is one strategy that should be satisfying to both laboratory scientists and administrators. This guest commentary describes one approach to quality improvement--the use of user surveys to identify areas for improvement. As an initial attempt to define such areas in clinical diagnostic microbiology, infectious disease specialists, targeted for their particular interest and expertise in microbiology laboratory results, were polled and their responses were analyzed. Some of these data have been presented previously (E. J. Baron, D. P. Francis, and K. M. Peddecord, abstr. C-170, p. 520, in Abstracts of the 94th General Meeting of the American Society for Microbiology, 1994; K. M. Peddecord, E. J. Baron, D. P. Francis, and A. S. Benenson, abstr. C-172, p. 520, in Abstracts of the 94th General Meeting of the American Society for Microbiology, 1994; K. M. Peddecord, E. J. Baron, D. P. Francis, and J. A. Drew, Am. J. Clin. Pathol. 105:58-64, 1996). The discussion includes our recommendations for the use of these survey responses, and their limitations, as stimuli to initiate reexamination of certain microbiology laboratory practices in the interest of developing more cost-effective and clinically relevant protocols.

Quality perceptions of microbiology services. A survey of infectious diseases specialists.

Opinions about the quality of their primary microbiology laboratory were received from more than 500 practicing infectious diseases specialists by a nationally distributed questionnaire. Approximately 92% of the respondents' primary laboratories were hospital-based. These sophisticated users rated the quality of their microbiology laboratories to be generally high, with bacteriology receiving highest scores and parasitology the lowest scores. Fortunately, the serious problems, such as failing to call a critical result and culture mishandled in the laboratory, were experienced rarely. Laboratories directed by pathologists with specialty microbiology training, PHD microbiologists, and infectious diseases specialists were judged to be of highest quality. American Board of Medical Microbiology certification of the laboratory director was related to higher overall quality perceptions. Whereas physician-customer opinions may not directly measure a laboratory's analytic quality, they are an important performance measure on which laboratories can base quality improvement activities in both service and analytical aspects of performance.

Quality management and the clinical microbiology laboratory.

Quality management in today's health care environment requires a fresh approach. Laboratories that have traditionally directed their efforts toward meeting the needs of physicians must now also satisfy the needs of society, the greater public health, and the agency's administrators. Technical advances must today be considered in the context of patient care cost-effectiveness or final outcomes. Examples of strategies for improving quality in the laboratory, such as seeking input from all individuals involved in interpreting or using laboratory test results, forming multidisciplinary committees for development of critical pathways, issuing surveys for assessing the level of satisfaction of the laboratory's customers, and providing visual feedback of the results of activities, are described.

Impact of CLIA 88 on the clinical microbiology laboratory.

The Clinical Laboratory Improvement Amendments (CLIA 88) to the Clinical Laboratory Improvement Act of 1967 continues to undergo transformation since its implementation more than 2 years ago. The law and its subsequent regulatory modifications were intended to promote high quality in and accurate results from laboratory testing procedures, regardless of the site at which testing occurred. A number of federal regulatory agencies and committees such as the Healthcare Financing Administration, the Clinical Improved Amendments Committee, and the Commission on Laboratory Accreditation, as well as numerous new or modified regulations and requirements have gained importance since CLIA 88 was enacted. In this discussion, components of CLIA 88 that have the greatest impact on clinical microbiology laboratories are presented. In addition, the potential future significance of CLIA 88 are outlined.

Genetic aspects of methicillin resistance in Staphylococcus aureus and methods used for its detection in clinical laboratories in the United States.

The mecA gene in methicillin-resistant Staphylococcus aureus (MRSA) directs production of a novel penicillin-binding protein (PBP 2A), an enzyme active in cell wall synthesis. MecA, alone, however, does not determine the degree of resistance expressed by strains of MRSA. Differential resistance or variations in other genes that participate in cell wall synthesis, such as laboratory mutant fem genes, may account, in part, for the heterogeneity of methicillin resistance expression in MRSA. The exact mechanisms of methicillin resistance expression in clinical isolates remain to be elucidated. Laboratories use selective agars containing oxacillin and turbidity pattern recognition programs in automated instruments to identify MRSA, although not all mecA-containing strains are detected. Until a rapid and inexpensive DNA probe assay is widely available, newer test methods such as the E test (AB Biodisk), oxidation-reduction indicators in MIC trays (Alamar), and the rapid fluorescent BBl. Crystal system seem promising.

Survival of anaerobes in original specimens transported by overnight mail services.

Overnight mail delivery was evaluated for its effect on the recovery of facultative and anaerobic microbes in cultures of clinical specimens from patients. Ten clinical specimens, which were collected at different geographic locations and during different weather conditions, were cultured at the site and after overnight delivery to a distant laboratory. Forty-five facultative anaerobic isolates and 48 anaerobes were recovered. There was no significant difference in numbers of strains or relative quantities recovered in cultures of transported and nontransported specimens. With proper collection, transport, and inoculation of specimens, overnight delivery did not compromise recovery of clinically relevant microbes.