Glutathione S-transferase alpha 4 induction by activator protein 1 in colorectal cancer

Glutathione S-transferase alpha 4 (GSTA4) is a phase II detoxifying enzyme that metabolizes electrophiles and carcinogens including 4-hydroxy-2-nonenal (4-HNE), an endogenous carcinogen that contributes to colorectal carcinogenesis. In this study, we investigated GSTA4 expression and regulation in murine primary colonic epithelial cells, microbiome-driven murine colitis and human carcinomas. Exposure of YAMC cells to 4-HNE induced Gsta4 expression. Using an inflammation-associated model of colorectal cancer (CRC), Gsta4 expression increased in vivo in colon macrophages and serum after 2 weeks of colonization of IL-10 deficient (Il10^-/-) mice with Enterococcus faecalis. Increased expression was noted after 9 months of colonization in colon macrophages and epithelia in areas of inflammation. In human colon biopsies, immunohistochemistry showed no GSTA4 expression in normal epithelial cells, whereas GSTA4 was strongly expressed in the neoplastic epithelia of invasive carcinomas. For tubular adenomas, increased expression was primarily noted in stromal macrophages. Increased GSTA4 was confirmed in established human CRC cell lines and associated with 4-HNE-protein adducts in human colon adenomas and CRC. Next, we showed that 4-HNE induced activation of c-Jun and Nrf2, two components of the oncogenic transcription factor AP-1. AP-1 inhibitors and gene-specific small interfering RNAs partially suppressed GSTA4 expression. Co-immunoprecipitation confirmed interactions between c-Jun and Nrf2 supporting a role for AP-1 in regulating 4-HNE-induced GSTA4 expression. These findings demonstrate GSTA4 activation during 4-HNE-induced neoplastic transformation in colorectal carcinogenesis. GSTA4 is a potential surrogate biomarker for CRC screening and should provide novel approaches for chemoprevention.

Infections with Ehrlichia chaffeensis and Ehrlichia ewingii in persons coinfected with human immunodeficiency virus

The clinical course and laboratory evaluation of 21 patients coinfected with human immunodeficiency virus (HIV) and Ehrlichia chaffeensis or Ehrlichia ewingii are reviewed and summarized, including 13 cases of ehrlichiosis caused by E. chaffeensis, 4 caused by E. ewingii, and 4 caused by either E. chaffeensis or E. ewingii. Twenty patients were male, and the median CD4(+) T lymphocyte count was 137 cells/microL. Exposures to infecting ticks were linked to recreational pursuits, occupations, and peridomestic activities. For 8 patients, a diagnosis of ehrlichiosis was not considered until > or =4 days after presentation. Severe manifestations occurred more frequently among patients infected with E. chaffeensis than they did among patients infected with E. ewingii, and all 6 deaths were caused by E. chaffeensis. Ehrlichiosis may be a life-threatening illness in HIV-infected persons, and the influence of multiple factors, including recent changes in the epidemiology and medical management of HIV infection, may increase the frequency with which ehrlichioses occur in this patient cohort.

Extracellular superoxide production by Enterococcus faecalis requires demethylmenaquinone and is attenuated by functional terminal quinol oxidases

The intestinal commensal bacterium, Enterococcus faecalis, is unusual among prokaryotic organisms in its ability to produce substantial extracellular superoxide. Transposon mutagenesis, allelic replacement, and electron spin resonance (ESR)-spin trapping showed that superoxide production and generation of derivative hydroxyl radical were dependent on membrane-associated demethylmenaquinone. Extracellular superoxide was generated through univalent reduction of oxygen by reduced demethylmenaquinone. Moreover, extracellular superoxide production was inhibited by exogenous haematin, an essential cofactor for cytochrome bd, and by fumarate, a substrate for fumarate reductase. As integral membrane quinol oxidases, cytochrome bd and fumarate reductase redox cycle demethylmenaquinone, and are necessary for aerobic and anaerobic respiration respectively. A rat model of intestinal colonization demonstrated that conditions exist in the mammalian intestinal tract that permit a mode of respiration for E. faecalis that results in the formation of hydroxyl radical. These results identify and characterize the mechanism by which E. faecalis generates extracellular free radicals.

Identification of a p28 gene in Ehrlichia ewingii: evaluation of gene for use as a target for a species-specific PCR diagnostic assay

PCR was used to amplify a 537-bp region of an Ehrlichia ewingii gene encoding a homologue of the 28-kDa major antigenic protein (P28) of Ehrlichia chaffeensis. The E. ewingii p28 gene homologue was amplified from DNA extracted from whole blood obtained from four humans and one canine with confirmed cases of infection. Sequencing of the PCR products (505 bp) revealed a partial gene with homology to outer membrane protein genes from Ehrlichia and Cowdria spp.: p30 of Ehrlichia canis (< or =71.3%), p28 of E. chaffeensis (< or =68.3%), and map1 of Cowdria ruminantium (67.3%). The peptide sequence of the E. ewingii partial gene product was deduced (168 amino acids) and the antigenicity profile was analyzed, revealing a hydrophilic protein with < or =69.1% identity to P28 of E. chaffeensis, < or =67.3% identity to P30 of E. canis, and < or =63.1% identity to MAP1 of C. ruminantium. Primers were selected from the E. ewingii p28 sequence and used to develop a species-specific PCR diagnostic assay. The p28 PCR assay amplified the expected 215-bp product from DNA that was extracted from EDTA-treated blood from each of the confirmed E. ewingii infections that were available. The assay did not produce PCR products with DNA extracted from E. chaffeensis-, E. canis-, or E. phagocytophila-infected samples, confirming the specificity of the p28 assay for E. ewingii. The sensitivity of the E. ewingii-specific PCR assay was evaluated and determined to detect as few as 38 copies of the p28 gene.

A double-blind placebo-controlled crossover trial of intravenous magnesium sulfate for foscarnet-induced ionized hypocalcemia and hypomagnesemia in patients with AIDS and cytomegalovirus infection

Foscarnet (trisodium phosphonoformate hexahydrate) is an antiviral agent used to treat cytomegalovirus disease in immunocompromised patients. One common side effect is acute ionized hypocalcemia and hypomagnesemia following intravenous administration. Foscarnet-induced ionized hypomagnesemia might contribute to ionized hypocalcemia by impairing excretion of preformed parathyroid hormone (PTH) or by producing target organ resistance. Prevention of ionized hypomagnesemia following foscarnet administration could blunt the development of ionized hypocalcemia. To determine whether intravenous magnesium ameliorates the decline in ionized calcium and/or magnesium following foscarnet infusions, MgSO(4) at doses of 1, 2, and 3 g was administered in a double-blind, placebo-controlled, randomized, crossover trial to 12 patients with AIDS and cytomegalovirus disease. Overall, increasing doses of MgSO(4) reduced or eliminated foscarnet-induced acute ionized hypomagnesemia. Supplementation, however, had no discernible effect on foscarnet-induced ionized hypocalcemia despite significant increases in serum PTH levels. No dose-related, clinically significant adverse events were found, suggesting that intravenous supplementation with up to 3 g of MgSO(4) was safe in this chronically ill population. Since parenteral MgSO(4) did not alter foscarnet-induced ionized hypocalcemia or symptoms associated with foscarnet, routine intravenous supplementation for patients with normal serum magnesium levels is not recommended during treatment with foscarnet.

Outcomes of an antimicrobial control program in a teaching hospital

The clinical outcomes and cost-effectiveness of an antimicrobial control program (ACP) were studied. The impact of an ACP in a teaching hospital was analyzed by comparing clinical outcomes and intravenous antimicrobial costs over two two-year periods, the two years before the program and the first two years after the program's inception. Admission baseline data, length of stay, mortality, and readmission rates were gathered for each patient. Patients were identified by using the International Classification of Diseases. Multivariate logistic regression models were constructed for mortality and for lengths of stay of 12 or more days. The acquisition costs of intravenous antimicrobial agents for the second baseline year and the entire program period were tabulated and compared. The average daily inpatient census was determined. The ACP was associated with a 2.4-day decrease in length of stay and a reduction in mortality from 8.28% to 6.61%. Rates of readmission for infection within 30 days of discharge remained about the same. Inpatient pharmacy costs other than intravenous antimicrobials decreased an average of only 5.7% over the two program years, but the acquisition cost of intravenous antimicrobials for both program years yielded a total cost saving of $291,885, a reduction of 30.8%. The institution's average daily census fell 19% between the second baseline year and the second program year. An ACP directed by a clinical pharmacist trained in infectious diseases was associated with improvements in inpatient length of stay and mortality. The ACP decreased intravenous antimicrobial costs and facilitated the approval process for restricted and nonformulary antimicrobial agents.

Infection-derived Enterococcus faecalis strains are enriched in esp, a gene encoding a novel surface protein

We report the identification of a new cell wall-associated protein of Enterococcus faecalis. Studies on the distribution of the gene encoding this novel surface protein, Esp, reveal a significant (P < 0.001) enrichment in infection-derived E. faecalis isolates. Interestingly, the esp gene was not identified in any of 34 clinical E. faecium isolates or in 4 other less pathogenic enterococcal species tested. Analysis of the structural gene among various E. faecalis isolates reveals the existence of alternate forms of expression of the Esp protein. The deduced primary structure of the Esp protein from strain MMH594, inferred to be 1,873 amino acids (aa) with a predicted mass of approximately 202 kDa, reveals a core region consisting of repeat units that make up 50% of the protein. Esp bears global organizational similarity to the Rib and C alpha proteins of group B streptococci. Identity among Esp, Rib, and C alpha proteins is strikingly localized to a stretch of 13 aa within repeats of similar length. The high degree of conservation of this 13-residue sequence suggests that it plays an important role in the natural selection for this trait among infection-derived E. faecalis and group B streptococcal isolates.

Prospective case-cohort study of intestinal colonization with enterococci that produce extracellular superoxide and the risk for colorectal adenomas or cancer

OBJECTIVE

The aim of this study was to determine whether intestinal colonization with enterococci that produce extracellular superoxide (O2*-), a free radical implicated in the development of colorectal cancer, is associated with these lesions or their precursors.

METHODS

A prospective case-cohort study was performed by isolating enterococci from stools of consecutive patients undergoing colonoscopy who had no prior history of colonoscopy or colorectal cancer. A food frequency questionnaire was also administered to control for dietary factors known to affect the risk for these lesions.

RESULTS

Among 159 evaluable participants were 77 with no precancerous or cancerous pathology, 61 with adenomas <2 cm, 10 with adenomas > or =2 cm, and 11 with cancer. Regression analyses found no associations for those subjects with adenomas of any size or with cancer and colonization with O2*--producing enterococci, any nutrient, or age. For those patients with large adenomas > or = 2 cm or cancer, however, significant associations were noted for age (OR 1.94 per decade, 95% CI 1.2-3.5), beta-carotene (OR 0.44 per 500 microg/1000 kcal/day, 95% CI 0.2-0.8), vitamin A (OR 3.20 per 500 microg/1000 kcal/day, 95% CI 1.2-8.9), and vitamin E (OR 0.09 per 10 mg/ 1000 kcal/day, 95% CI 0.006-0.9), but not colonization with O2*--producing enterococci. Second stools collected 1 yr later, however, often contained dissimilar enterococcal flora, undermining an important study assumption.

CONCLUSIONS

Significant associations were found for those with large adenomas or cancer (but not small adenomas), with age, and with foods enriched for vitamin A, vitamin E, and beta-carotene. An association between colonization with O2*--producing enterococci and colorectal adenomas or cancer, however, could not be ascertained, possibly because intestinal enterococcal flora changes over time, leaving a potentially cohesive hypothesis of colon cancer and risk factors as yet unanswered.

A hospital-based pharmacy intervention program for pneumococcal vaccination

BACKGROUND

Current pneumococcal vaccination rates are well below national goals.

OBJECTIVE

To determine whether pneumococcal vaccination rates could be increased with a hospital pharmacy-based program using simple chart reminders.

METHODS

On a daily basis, inpatient records on general medicine and cardiology services at an academic medical center were reviewed to determine which patients were eligible to receive pneumococcal vaccine. Eligible inpatients were interviewed, and the percentage of nonvaccinated inpatients given vaccine during hospitalization was determined. During an intervention period, reminders were placed on charts after the interview requesting a vaccine when indicated.

RESULTS

Of 447 inpatients, 224 (50.1%) had 1 or more indications for receiving pneumococcal vaccine. Only 64 (28.6%) had been previously vaccinated. One hundred fifty-eight (70.5%) of 224 vaccine-eligible patients had a prior hospitalization within the previous 5 years. Previous hospitalization was not significantly associated with having (48 [30.4%] of 158) or not having (16 [24.2%] of 66; P=.35) been vaccinated prior to admission. During the observational period, 0 of 80 vaccine-eligible, nonvaccinated inpatients were vaccinated before discharge. In comparison, 23 (28.8%) of 80 inpatients were vaccinated after a chart reminder (P<.001). During the intervention period, vaccination rates were 10-fold higher on general medicine services than on cardiology services.

CONCLUSIONS

A hospital-based pharmacy vaccination program that relied on simple chart reminders was significantly associated with increased vaccination rates among inpatients at risk for invasive pneumococcal disease.

Multiple-drug resistant enterococci: the nature of the problem and an agenda for the future

Enterococci, leading causes of nosocomial bacteremia, surgical wound infection, and urinary tract infection, are becoming resistant to many and sometimes all standard therapies. New rapid surveillance methods are highlighting the importance of examining enterococcal isolates at the species level. Most enterococcal infections are caused by Enterococcus faecalis, which are more likely to express traits related to overt virulence but--for the moment--also more likely to retain sensitivity to at least one effective antibiotic. The remaining infections are mostly caused by E. faecium, a species virtually devoid of known overt pathogenic traits but more likely to be resistant to even antibiotics of last resort. Effective control of multiple-drug resistant enterococci will require 1) better understanding of the interaction between enterococci, the hospital environment, and humans, 2) prudent antibiotic use, 3) better contact isolation in hospitals and other patient care environments, and 4) improved surveillance. Equally important is renewed vigor in the search for additional drugs, accompanied by the evolution of new therapeutic paradigms less vulnerable to the cycle of drug introduction and drug resistance.

Surgical Infection Society position on vancomycin-resistant Enterococcus

The risk of transfer of vancomycin resistance to staphylococci is a real possibility and has been achieved in the laboratory. Prolonged colonization occurs with vancomycin-resistant Enterococcus (VRE), and many more patients are colonized than infected. The failure to identify, isolate, and adhere to infection control measures when caring for VRE-colonized patients dooms to failure any means to control its spread. Control of vancomycin use alone is unlikely to greatly affect the number of patients at risk for VRE colonization. The global spread of VRE may be impossible to stop, but infection control measures are the most important line of defense inside hospitals.

Augmented production of extracellular superoxide by blood isolates of Enterococcus faecalis

To assess the frequency of extracellular superoxide (O-2) production by enterococci, multiple species were surveyed in a whole organism assay for their ability to reduce ferricytochrome c in a superoxide dismutase-inhibitable fashion. For stool and clinical enterococcal isolates and 12 type strains, only Enterococcus faecalis (87/91 isolates and ATCC 19433), Enterococcus faecium (5/13 isolates), Enterococcus casseliflavus (ATCC 25778), and Enterococcus gallinarum (ATCC 35038) produced extracellular O-2. Among 106 strains comprising 13 species of enteric gram-negative bacilli and gram-positive cocci, only Lactococcus lactis subspecies lactis produced extracellular O-2. Mean (+/-SE) rates of extracellular O-2 production in vitro by E . faecalis for isolates associated with bacteremia and endocarditis and for isolates from stool were 2.4+/-0.2, 1.9+/-0.2, 1.5+/-0.3 nmol of O-2 min(-1) 10(9) cfu(-1), respectively (P=.025, analysis of variance), suggesting an association between invasiveness and extracellular O-2 production.

Frequency of aggregation substance and cytolysin genes among enterococcal endocarditis isolates

Enterococcus faecalis blood isolates were probed for the serine protease activator of cytolysin (cylA) and aggregation substance (asa1), traits that generally reside on pheromone-responsive plasmids, to determine how commonly these genotypes were associated with disease. In dot blot assays, no significant difference was found in the frequency of asa1 for blood isolates [55 of 103 (54%)] and isolates recovered from stool [9 of 14 (60%); P > 0.1, chi 2 test]. In contrast, cylA occurred more frequently among bacteremia isolates [34 of 68 (50%)] than endocarditis [4 of 35 (11%)] or stool isolates (0 of 14; P < 0.001; chi 2 test). However, when the clonality of isolates was accounted for, the frequency of asa1 and cylA among unrelated strains was not significantly different among the three sets of strains (P > 0.2, chi 2 test). The lack of enrichment for asa1 or cylA among clonally unrelated E. faecalis bloodstream isolates fails to support a role for plasmid-encoded aggregation substance or cytolysin in the transition from bacteremia to endocarditis. Clonally related, cytolytic strains, however, demonstrated an increased propensity to cause bloodstream infection.

Apophysomyces elegans infection in a renal transplant recipient

A 50-year-old cadaveric renal transplant recipient on immunosuppressive therapy is described with post-traumatic cutaneous infection caused by Apophysomyces elegans. He showed no evidence of hematogenous dissemination and recovered fully after therapy with extensive local debridement and amphotericin B lipid complex. An apparent drug-drug interaction between amphotericin B lipid complex and cyclosporine was encountered. The course of A elegans infection in transplant recipients may be similar to that described in immunocompetent hosts. A elegans infection should be considered in evaluation of post-traumatic cutaneous infection not readily responsive to antibacterial therapy.

Enterococcus faecalis cytolysin without effect on the intestinal growth of susceptible enterococci in mice

A murine model was developed to determine whether the Enterococcus faecalis cytolysin, through its bacteriolytic action on gram-positive bacteria, could promote intestinal overgrowth of cytolytic strains. Sets of E. faecalis strains with varying cytolytic production and susceptibility to cytolytic activity were mixed 1:1 and allowed to compete in vitro in broth or in vivo after orogastric administration in mice pretreated with antibiotics. In general, cytolytic strains outgrew, by as much as 2000-fold, competing cytolysin-susceptible or -hypersusceptible strains in vitro. In contrast, no growth advantage was observed in vivo, despite similar transient colonization of the murine intestinal tract by both cytolytic and cytolysin-susceptible strains. These data suggest that cytolysin plays little role in promoting intestinal overgrowth of enterococci through bacteriolytic activity.

Virulence of enterococci

Enterococci are commensal organisms well suited to survival in intestinal and vaginal tracts and the oral cavity. However, as for most bacteria described as causing human disease, enterococci also possess properties that can be ascribed roles in pathogenesis. The natural ability of enterococci to readily acquire, accumulate, and share extrachromosomal elements encoding virulence traits or antibiotic resistance genes lends advantages to their survival under unusual environmental stresses and in part explains their increasing importance as nosocomial pathogens. This review discusses the current understanding of enterococcal virulence relating to (i) adherence to host tissues, (ii) invasion and abscess formation, (iii) factors potentially relevant to modulation of host inflammatory responses, and (iv) potentially toxic secreted products. Aggregation substance, surface carbohydrates, or fibronectin-binding moieties may facilitate adherence to host tissues. Enterococcus faecalis appears to have the capacity to translocate across intact intestinal mucosa in models of antibiotic-induced superinfection. Extracellular toxins such as cytolysin can induce tissue damage as shown in an endophthalmitis model, increase mortality in combination with aggregation substance in an endocarditis model, and cause systemic toxicity in a murine peritonitis model. Finally, lipoteichoic acid, superoxide production, or pheromones and corresponding peptide inhibitors each may modulate local inflammatory reactions.

Characteristics of potential plaintiffs in malpractice litigation

OBJECTIVE

To characterize patients calling plaintiff attorneys' offices and claiming to have suffered injury caused by medical negligence.

DESIGN

Telephone interviews with an inception cohort of callers to law firms with malpractice complaints before the callers talk to attorneys.

SETTING

Six law offices in five states.

PARTICIPANTS

502 of 730 callers over 10 randomly selected days in 1991.

MEASUREMENTS

Demographics of potential plaintiffs, types of health care providers named by callers, factors prompting calls, economic and noneconomic motivations for claims, and disposition of claims.

RESULTS

An average of 12 calls per office per day were received by law firms concerning malpractice complaints. Many factors affected patients' decisions to call: poor relationships with providers before an injury (53%); television advertising by law firms (73%); explicit recommendations by health care providers to seek legal counsel (27%); impressions of not being kept informed or appropriately referred by providers; and financial concerns (for example, 36% with earned income and outstanding medical bills had bills equaling or exceeding 50% of their annual income, 33% were unemployed, and 31% lacked health insurance). One in 30 calls led to the filing of a lawsuit.

CONCLUSIONS

Calls to plaintiff law firms by patients are common, are motivated by diverse factors, represent dissatisfaction with modern health care, and infrequently lead to lawsuits.

Rhodococcus equi infections of humans. 12 cases and a review of the literature

Increased recognition of Rhodococcus equi as a human pathogen has occurred since 1983, when the first review article summarized the world's literature of 12 cases. In this article, we present 12 cases from the University of Oklahoma Health Sciences Center and review 60 from the literature. Most cases occur in immunocompromised hosts and present as chronic cavitary pneumonias. Associated extrapulmonary disease is seen at diagnosis in 7% of patients with pneumonia, and relapse occurs at extrapulmonary sites in 13%, often without reappearance of pulmonary disease. Relapse may follow a course of antimicrobial therapy that is too brief, but can also occur during treatment. Infections also occur in the gastrointestinal tract, causing enteritis and regional adenitis with abscesses. Contaminated wounds may become infected. Isolated bacteremias may be a manifestation of latent infection recurring during a period of immune suppression. A common feature of human R. equi infection is delay in diagnosis. The insidious course of disease contributes to delay, as does failure to identify the organism. R. equi is easily cultured on nonselective media but commonly mistaken for a diphtheroid or occasionally for a mycobacterium based on acid-fast appearance. Form and duration of treatment are closely related to host immune status. Immunocompromised patients require prolonged or indefinite therapy with multiple antibiotics. Infections in immunocompetent hosts are easily treated with short courses of single agents. Infections related to contaminated wounds are treated primarily by irrigation and debridement. Infections in immunocompromised hosts are increasing in frequency largely due the AIDS epidemic. Infections in immunocompetent hosts, reported rarely before this series, may be underdiagnosed, perhaps because R. equi resembles common commensals and has limited virulence in this population. This report demonstrates that R. equi infections, including community-acquired pneumonias, occur in immunocompetent hosts.

Clinical experience with HIV-infected patients at the University of Oklahoma Health Sciences Center: an update

We reviewed the course of 545 human immunodeficiency virus (HIV)-infected patients seen between 1983 and March 30, 1991. A majority were Caucasian homosexual or bisexual men, while parenteral drug abusers represented a smaller proportion than seen nationwide. In the 274 patients with the acquired immunodeficiency syndrome (AIDS), the distribution of AIDS-defining conditions was generally consistent with those reported in studies from elsewhere in the United States. However, toxoplasmosis remained relatively uncommon. There was a slightly higher incidence of disseminated histoplasmosis compared to other studies. HIV encephalopathy (AIDS dementia) was likely underdiagnosed. Although data suggested prolongation of the asymptomatic phase of HIV infection, median survival after AIDS diagnosis remained approximately 12 months.

Transfer of pheromone-inducible plasmids between Enterococcus faecalis in the Syrian hamster gastrointestinal tract

Pheromone-responsive plasmids are common to Enterococcus faecalis, transfer at high frequency in vitro, and carry cytolysin and other gene products implicated in the pathogenesis of enterococcal infection. A Syrian hamster model of enterococcal intestinal overgrowth was used to test for transfer of three isogenic plasmids differing in conjugative and cytolytic phenotypes. Transconjugants were found in 8 (44%) of 18 and 6 (35%) of 17 hamsters given donor strains containing cytolytic (pAM714) and noncytolytic (pAM771) pheromone-responsive plasmids. Of the 14 hamsters from which transconjugants were isolated from stool, 9 (64%) had transconjugants 1 day after donor strain inoculation. The frequency of transfer (mean +/- SD) for pAM714 and pAM771 was 1.4 +/- 2.2 x 10(-1) and 2.9 +/- 4.2 x 10(-2) transconjugants/donor, respectively (P > .20). Transconjugants were not recovered from hamsters receiving a cytolytic, nonconjugative plasmid (pAM930; transfer frequency < 2 x 10(-5) transconjugants/donor). Pheromone-responsive plasmid transfer between E. faecalis strains occurs at high frequency in the gastrointestinal tract of hamsters and may be one means by which enterococcal resistance and virulence factors disseminate.

Prevalence of antibody to Borrelia burgdorferi by indirect fluorescent antibody assay, ELISA, and western immunoblot in healthy adults in Wisconsin and Arizona

The prevalence of antibody to Borrelia burgdorferi in healthy adults from Wisconsin and Arizona was determined by indirect fluorescent antibody assay (IFA), ELISA, and Western immunoblotting. A total of 301 sera from adult volunteer blood donors were collected from three areas of Wisconsin and compared with 49 consecutive anonymous adult volunteer donor sera from Tucson, Arizona, an area without reported Lyme borreliosis. Regional differences in seropositivity were found for Western immunoblotting (34[11%] of 301 from Wisconsin and none of 49 from Tucson; P less than .01) but not IFA or ELISA. No correlation was found among Western immunoblotting and IFA or ELISA results. For persons living in Madison or Milwaukee, Wisconsin (cities not endemic for Lyme borreliosis), 19 (86%) of 22 with a positive Western blot, but only 12 (48%) of 25 with a positive IFA or ELISA, had a significant exposure risk to B. burgdorferi-infected Ixodes dammini (odds ratio, 6.9; 95% confidence interval, 1.4-43.5). Western blot results were consistent with epidemiologic exposure to B. burgdorferi and implied frequent asymptomatic infection among healthy adults living in or visiting areas endemic for Lyme borreliosis.

The descriptive epidemiology of Lyme disease in Oklahoma

Lyme disease is a tick-borne illness that primarily occurs in the United States in three endemic areas: the northeast, upper midwest, and pacific coastal regions. Although Oklahoma is considered a non-endemic area of Lyme disease, other tick-borne infections such as Rocky Mountain spotted fever, ehrlichiosis, and tularemia occur at endemic levels. In order to determine the extent of Lyme disease in Oklahoma, the Oklahoma State Department of Health collected information on all possible cases of Lyme disease. The first reported Oklahoma case occurred in 1985. In 1988, and 1989, 8 and 25 cases, respectively, of Lyme disease were reported in Oklahoma residents who acquired their infection indigenously. The mean age of case-patients was 38 years. Twenty-eight of 33 (85%) case-patients were white, and 4 of 33 (12%) were American Indian (race was unknown for 1 case-patient). The female/male ratio was 2.3. Most case-patients had onset of illness between May and September. Twenty-two counties reported cases, with Oklahoma County accounting for 4 of 33 (12%). Only 21 of 33 (64%) recalled a tick bite, and only 19 of 33 (58%) had erythema migrans. Continued active case-finding and passive reporting (as now mandated by state law) will further increase our knowledge of the epidemiology, ecology, and prevention of Lyme disease in Oklahoma.

Bacteremia caused by hemolytic, high-level gentamicin-resistant Enterococcus faecalis

Between 1 January 1984 and 31 December 1987, 206 enterococcal blood isolates at the University of Wisconsin Hospital and Clinics were analyzed for high-level aminoglycoside resistance (hereafter high-level aminoglycoside resistance is simply referred to as "resistance") and hemolysin production. Of 190 Enterococcus faecalis isolates, 68 (35.8%) were resistant to gentamicin. Of these 68 strains, 67 (98.5%) contained a gene coding for the bifunctional aminoglycoside-modifying 6'-aminoglycoside acetyltransferase-2"-aminoglycoside phosphotransferase [AAC(6')-APH(2")] enzyme. Of 190 isolates, 85 (44.7%) were hemolytic and contained a gene coding for component A of the enterococcal hemolysin. Sixty-two of 68 (91.2%) gentamicin-resistant isolates but only 23 of 122 (18.8%) gentamicin-susceptible isolates were hemolytic (P less than 0.001). Twelve of the hemolytic, gentamicin-resistant E. faecalis blood isolates, but only 2 of 9 nonhemolytic or gentamicin-susceptible isolates, had identical chromosomal DNA restriction endonuclease digestion patterns, suggesting a common derivation for these strains. A historical cohort study from 1 July 1985 to 31 March 1987 identified by regression analysis postsurgical intensive care unit status (odds ratio [OR], 5.0; 95% confidence interval [CI], 1.1 to 22.8) and prior treatment with an expanded- or broad-spectrum cephalosporin (OR, 3.0; 95% CI, 0.9 to 10.1) as risk factors for gentamicin-resistant E. faecalis bacteremia. Patients with hemolytic, gentamicin-resistant E. faecalis bacteremia had a fivefold-increased risk for death within 3 weeks of their bacteremia compared with patients with nonhemolytic, gentamicin-susceptible strains (95% CI, 1.0 to 25.4).

Enterococcus: an old pathogen with new tricks

Recent clinical enterococcal isolates from the Oklahoma City Department of Veterans Affairs Medical Center were screened for high-level aminoglycoside resistance, vancomycin resistance, beta-lactamase production, and hemolysin production. Twenty-nine of 53 (55%) enterococcal isolates had high-level resistance to gentamicin, kanamycin, or streptomycin; 27 of these isolates were from the blood and 16 (59%) showed high-level gentamicin resistance. Twenty-one percent of 259 enterococcal isolates from blood, urine, stool, and other sources were hemolytic. Of thirteen blood isolates tested for both high-level gentamicin resistance and hemolysin production, 6 (46%) showed both characteristics. Vancomycin-resistant or beta-lactamase-producing isolates were not found. Nineteen of 21 charts from patients with premortem enterococcal blood isolates were reviewed, and no correlation was found between appropriate antibiotic treatment for high-level gentamicin-resistant or susceptible enterococcal bacteremia and outcome. Enterococci with multiple high-level aminoglycoside resistance, but not vancomycin resistance or beta-lactamase production, are common at this referral medical center. Clinical microbiology laboratories in Oklahoma should routinely screen enterococcal isolates causing potentially serious infections (eg, from blood or cerebral spinal fluid) for high-level aminoglycoside resistance.

Molecular characterization of the Enterococcus faecalis cytolysin activator

The gene encoding component A (cylA), the activator protein of the Enterococcus faecalis cytolysin, has been localized on pAD1, and the nucleotide sequence was determined. cylA consists of a 1,236-bp open reading frame encoding a 412-amino-acid polypeptide. A search of the National Biomedical Research Foundation data base revealed significant homology between the inferred amino acid sequence of component A and subtilisin BPN'. Component A activation of the cytolysin precursor (component L) was observed to be inhibited by the serine protease inhibitor diisopropylfluorophosphate. Mature component A exhibits a molecular weight of approximately 30,000 and an isoelectric point of 4.5. Differences between the size of the primary translation product (45,625 daltons) and the mature enzyme suggest that, as for subtilisin, component A is secreted as a proenzyme. These results provide the basis for a model of component A activation of component L and a role for component A in protecting the cytolysin-producing cell from lysis.

N-Halo derivatives V: Comparative antimicrobial activity of soft N-chloramine systems

Comparative antimicrobial activity studies for certain new classes of soft N-chloramines derived from alpha-aminiisobutyric acid and 2-amino-2-methyl-1-propanol were examined using the minimum inhibitory concentration (MIC) and/or the contact germicidal efficiency (CGE) procedures. Several factors significantly aliphatic chain length in a homologous series, (b) the degree of chlorination of thenitrogen atom, (c) the solution pH, (d) the presence of a denaturant, and (e) the nature of a positive charge.