Health concerns of heterotrophic plate count (HPC) bacteria in dental equipment water lines.

There is an unsubstantiated concern as to the health relevance of HPC (heterotrophic plate count) bacteria in dental equipment waterlines. The American Dental Association (ADA) web site includes guidelines for controlling HPC populations and implies that HPC populations >500 CFU/mL as a "health" benchmark. The world-wide published literature including the United Nations fully examined this situation and concluded that HPC bacteria are not a health risk, but merely a general water quality parameter for all waters including dental water lines. This review provides documentation that the standard measurement of HPC bacteria in waters alone do not pose a health risk and the ADA already provides appropriate practices to minimize HPC bacteria in dental equipment water.

Drinking water microbial myths.

Accounts of drinking water-borne disease outbreaks have always captured the interest of the public, elected and health officials, and the media. During the twentieth century, the drinking water community and public health organizations have endeavored to craft regulations and guidelines on treatment and management practices that reduce risks from drinking water, specifically human pathogens. During this period there also evolved misunderstandings as to potential health risk associated with microorganisms that may be present in drinking waters. These misunderstanding or "myths" have led to confusion among the many stakeholders. The purpose of this article is to provide a scientific- and clinically-based discussion of these "myths" and recommendations for better ensuring the microbial safety of drinking water and valid public health decisions.

Growth of adenocarcinoma on routine microbiological media inoculated with fluid from a pleural effusion in an 82-year-old female.

We report the first documented case of adenocarcinoma cell growth on routine microbiological media. Pleural fluid culture from an 82-year-old female showed colonies with fried egg appearance on routine microbiological media that were negative for bacterial microorganisms. Stains of the colonies demonstrated clusters of viable neoplastic cells.

Does the possession of virulence factor genes mean that those genes will be active?

There are a number of relationships the host can establish with the microbes we ingest. For the vast majority of microbes, they have a short-lived liaison with the human host. Either they are destroyed by the stomach acid or bile, or can not establish even a temporary residency in the gastrointestinal tract. Early in life the mucosal surfaces of the body establishes a resident, and generally stable, normal flora. These normal flora microbes, the majority of which are bacteria, have specific receptors for specific areas of the alimentary tract. If the foreign microbe can establish residency, it then may transiently or permanently become part of the normal flora. However, in order to produce disease, it must possess an additional set of virulence factors. While some of these are known, many are not. Those that are known include enzymes, such as protease, lipase, and esterase. Accordingly, VFAR may not be associated with human disease and its presence or absence has no public health meaning.

Acute pyelonephritis caused by Aerococcus urinae in a 12-year-old boy.

Aerococcus urinae are Gram-positive cocci that cause urinary tract infections in adults with underlying genitourinary (GU) tract disease. We report a case of pyelonephritis caused by A. urinae in a 12-year-old boy with a history of pyeloplasty and GU reflux.

Use of real-time polymerase chain reaction for identification of methicillin-resistant Staphylococcus aureus directly from positive blood culture bottles.

The utility of real-time polymerase chain reaction (RT-PCR) testing for detection of methicillin-resistant Staphylococcus aureus (MRSA) directly from positive blood culture bottles was evaluated. One hundred forty-two blood cultures showing Gram-positive cocci in clusters were detected. Each blood culture sample was tested for the presence of MRSA by PCR analysis (SmartCycler) via detection of the mecA and orfX genes. In parallel, they were plated on standard media for identification and characterization. PCR analysis directly from the blood culture bottle required a total time of 120 min (45 min for preparation and 75 min for the reaction). By comparison, conventional laboratory procedures required between 48 and 72 h. The overall test accuracy was 97% with a high positive likelihood ratio and a low negative likelihood ratio.

Diarrheagenic Escherichia coli infection in Baltimore, Maryland, and New Haven, Connecticut.

BACKGROUND: Diarrhea remains a common complaint among US patients who seek medical attention. METHODS: We performed a prospective study to determine the etiology of diarrheal illness among patients and control subjects of all ages presenting to the emergency departments and outpatient clinics of 2 large academic hospitals in Baltimore, Maryland, and New Haven, Connecticut. We used molecular methods to detect the presence of diarrheagenic Escherichia coli pathotypes, including enteroaggregative E. coli (EAEC), as well as Shiga toxin-producing, cytodetaching, enterotoxigenic and enteropathogenic E. coli. RESULTS: Of the pathotypes sought, only EAEC was found in an appreciable proportion (4.5%) of case patients, and it was found more frequently among case patients than control subjects (P<.02). Surprisingly, EAEC was the most common bacterial cause of diarrhea in our population. EAEC was common in all age strata and was not associated with foreign travel or immunodeficiency. EAEC infection is frequently accompanied by fever and abdominal pain, though this did not happen more frequently in patients with EAEC infection than in patients with diarrhea due to other causes. CONCLUSIONS: Our data suggest that EAEC infection should be considered among persons with diarrhea that does not yield another known etiologic agent.

High rate of negative results of tuberculin and QuantiFERON tests among individuals with a history of positive skin test results.

OBJECTIVES: To evaluate individuals at high risk for tuberculosis exposure who had a history of a positive tuberculin skin test (TST) result in order to determine the prevalence of unsuspected negative TST results. To confirm these findings with the QuantiFERON-TB test (QFT), an in vitro whole-blood assay that measures tuberculin-induced secretion of interferon-gamma. METHODS: This survey was conducted from November 2001 through December 2003 at 3 sites where TST screening is regularly done. Detailed histories and reviews of medical records were performed. TSTs were placed and read by 2 experienced healthcare workers, and blood was drawn for QFT. Any subject with a negative result of an initial TST during the study (induration diameter, <10 mm) underwent a second TST and a second QFT. The TST-negative group comprised individuals for whom both TSTs had an induration diameter of <10 mm. The confirmed-negative group comprised individuals for whom both TSTs yielded no detectable induration and results of both QFTs were negative. RESULTS: A total of 67 immunocompetent subjects with positive results of a previous TST were enrolled in the study. Of 56 subjects who completed the TST protocol, 25 (44.6%; 95% confidence interval [CI], 31.6%-57.6%) were TST negative (P<.001). Of 31 subjects who completed the TST protocol and the QFT protocol, 8 (25.8%; 95% CI, 10.4%-41.2%) were confirmed negative (P<.005). CONCLUSIONS: A significant proportion of subjects with positive results of a previous TST were TST negative in this study, and a subset of these were confirmed negative. These individuals' TST status may have reverted or may never have been positive. It will be important in future studies to determine whether such individuals lack immunity to tuberculosis and whether they should be considered for reentry into tuberculosis screening programs.

Global Infectious Diseases and Epidemiology Network (GIDEON): a world wide Web-based program for diagnosis and informatics in infectious diseases.

The Global Infectious Diseases and Epidemiology Network (GIDEON) (http://www.gideononline.com) consists of 4 modules. The first is designed to generate a ranked differential diagnosis list for any infectious diseases scenario in any of 220 countries. The second follows the country-specific epidemiology of 337 individual diseases. The third presents a comprehensive encyclopedia of 308 generic anti-infective drugs and vaccines, including a listing of >9500 trade names. The fourth generates a ranked identification list based on the phenotype of bacteria, mycobacteria, and yeasts. The program performs well and serves as a useful paradigm for World Wide Web-based informatics. GIDEON is an eclectic program that can serve the needs of clinicians, epidemiologists, and microbiologists working in the fields of infectious diseases and geographic medicine.

Virulence and risk from drinking water of heterotrophic plate count bacteria in human population groups.

Bacteria are natural inhabitants of all aqueous environments. The heterotrophic plate count is a means of assessing the concentration of these bacteria in foods, water, and water filtration systems. Methods vary, but are designed to enumerate bacteria that have evolved an environmental lifestyle. Most commonly, low nutrient, low ionic strength culture media are employed. The group of environmental bacteria enumerated depends on the media formulation and incubation conditions but are commonly known as heterotrophic plate count (HPC) bacteria; in Europe, this group is also referred to as autochthonous flora. While HPC inhabit an environmental niche, there has been concern that at some concentration they may be a human health risk. A review of the literature, including animal and human feeding studies, analysis of virulence factors, and outbreaks demonstrates that HPC bacteria as enumerated on HPC culture media have not been established as a human health threat at any concentration in drinking water or foods.

Heterotrophic plate count bacteria--what is their significance in drinking water?

While the literature documents the universal occurrence of heterotrophic plate count (HPC) bacteria in soils, foods, air, and all sources of water, there is a lingering question as to whether this group of organisms may signal an increased health risk when elevated populations are present in drinking water. This paper reviews the relevant literature on HPC bacteria in drinking water, the lack of clinical evidence that elevated populations or specific genera within the HPC flora pose an increased health risk to any segment of the population, and the appropriate uses of HPC data as a tool to monitor drinking water quality changes following treatment. It finds no evidence to support health-based regulations of HPC concentrations.

Issues for microbial regulation: Aeromonas as a model.

The decision by public health agencies to regulate specific microorganisms that may be found in drinking water can only be made if specific criteria find that a microorganism poses a health risk. These criteria should include: (1) there is a clinical history of an organism causing disease from the ingestion of drinking water; (2) there is epidemiological evidence that drinking water rather than food or other vectors is a major source of disease; (3) there is sufficient evidence that the target organism, if found in water, possesses virulence factors capable of causing disease in humans; (4) there is sufficient evidence that the target organism is not readily removed or inactivated by multi-barrier conventional water treatment process (e.g., coagulation-filtration-disinfection); (5) there is sufficient evidence that the target organism, if surviving conventional treatment, will be viable, virulent, and present in sufficient numbers to cause disease; (6) there are robust analytical methods for the target organism which have acceptable sensitivity, specificity, and reproducibility to measure accurately the presence of the target organism in treated water; and (7) the performance criteria of analytical method(s) for the target organism have been certified by the appropriate public health agency, and there is intra-laboratory field-test performance data to base this certification.

Comparative microbial character of consumed food and drinking water.

Humans ingest large numbers of microbes daily. Food provides distinctly different physical and physiological conditions from drinking water. With high concentrations of carbohydrate, protein, and ionic strength, food is much closer to the human physiological state than drinking water, which is essentially devoid of nutrients and ionic strength. Accordingly, microbes that can multiply in humans and cause disease can grow in food, but do not multiply in drinking water. Virtually all food sources contain many thousand times more bacteria than drinking water. Therefore, based on both observed microbial content and the presence of large numbers of pathogens or their indicators in food, in this country food is more of a health risk to humans than drinking water. Compounding this disparity is the fact that much food is imported with limited control over the means of production. Naturally occurring bacteria (HPC or autochthonous flora) do not have virulence factors, making their numbers irrelevant to health risk except in the case of the most severely immunocompromised--a very defined population group. Consequently, public health regulations should not be directed to eliminating naturally occurring HPC, but should be focused toward controlling pathogens through measures such as sanitary crop systems in the steps from production (e.g., quality of irrigation and fertilization, animal feed lot sanitation) through storage to consumer preparation. Food possesses a far greater risk than drinking water, and government agencies should take this fact into account when writing regulations.

Identification of Bordetella pertussis in a critically ill human immunodeficiency virus-infected patient by direct genotypical analysis of Gram-stained material and discrimination from B. holmesii by using a unique recA gene restriction enzyme site.

Bordetella pertussis was diagnosed in a human immunodeficiency virus-infected patient by a newly developed method in which bacterial DNA is amplified directly from sputum Gram-stained slides. The validation of the method is described along with an additional new PCR-based assay that can distinguish between B. pertussis and Bordetella holmesii.