Dentistry and tuberculosis in the 1900s.

The number of new cases--or incidence--of tuberculosis is increasing in nearly every region of the world. A number of forces have resulted in the increased incidence of TB in developed countries, including the HIV epidemic, homelessness, and emigration from highly endemic regions. Although the number of new cases in Canada is relatively constant, the TB experience in the United States serves as a reminder that this situation could change rapidly. The appearance of multidrug-resistant tuberculosis has added to the urgency of situation. The basic methods of preventing TB transmission include preventing the release of the organism into the air, removing the organism from the air, and preventing the inhalation of the organism. Identifying and appropriately treating every person with active tuberculosis is an extremely important component of the control strategy; adequate ventilation, filtering air, and ultraviolet germicidal irradiation are methods used to remove the organism from the air; and masks and other personal protective devices, such as high-efficiency particulate air filters (HEPA), have been suggested as a means of preventing inhalation of the organism. In addition, identifying new TB infections and using chemoprophylaxis often prevents infection from progressing to active disease. Given the route by which tuberculosis is transmitted, it is necessary for both dentists and allied dental personnel to be aware of the risks they may face in day-to-day practice, and the means by which they can protect themselves and their patients.

The evaluation of the effectiveness of routine restaurant inspections and education of food handlers: critical appraisal of the literature.

Literature databases were scanned to locate articles pertaining to food handler education and restaurant inspection. Papers which met pre-established criteria, as described in the generic protocol produced by the Community Health Practice Guidelines Project (CHPG), were evaluated by standardized consideration of criteria. Studies were rated on a scale of one to three. There were eight papers related to the intervention of education, four papers dealing with the intervention of restaurant inspection, and one pertaining to both. the evidence presented in the papers regarding the effectiveness of food handler training in improving food establishment sanitation was weak, but it appeared that some training resulted in improved inspection scores. It appeared that inspections were beneficial, although it was not clear whether three or more inspections were better than two. No inspections appeared to result in worse inspection scores.

The evaluation of the effectiveness of routine restaurant inspections and education of food handlers: restaurant inspection survey.

To determine restaurant inspection and food handler education practices in Canada, a survey of 141 jurisdictions was conducted. The response rate was 100%. All jurisdictions inspected restaurants, but the frequency of routine inspection varied from none to six or more times per year. The frequency of violations found on routine inspection was associated with foodborne illness. However, the frequency of inspection was not correlated with disease or with violations. Food handler education courses were mandatory in 32% of jurisdictions. Most courses were one to two days. No correlation was found between the numbers of individuals trained in the past year and violations or reported foodborne disease. This lack of reduction in reported foodborne illness may be due to the ecological nature of the survey or to the lack of effectiveness of food handler education or of routine restaurant inspections in reducing violations.

An approach to the development of practice guidelines for community health interventions.

The Community Health Practice Guidelines (CHPG) project was initiated to develop a systematic approach to the critical evaluation of evidence on the effectiveness and efficiency of community health interventions and to the formulation of evidence-based practice recommendations. Three community health interventions--immunization delivery methods, partner notification for sexually transmitted diseases and the combination of restaurant inspection and education of food handlers--were used as prototypes to develop a standardized approach. The CHPG process consists of three components: a review of scientific evidence, a practice survey and formulation of practice guidelines. Imperatives for further development of the CHPG and define research priorities process include creating a coalition of public health organizations to sponsor the process and refining the consensus process so that the practice guidelines accurately reflect both the scientific basis of public health practice and the values of those affected.

Routine restaurant inspections and education of food handlers: recommendations based on critical appraisal of the literature and survey of Canadian jurisdictions on restaurant inspections and education of food handlers.

Inspection of restaurants and education of food handlers are two methods used by regulatory agencies to ensure food served in restaurants is safe to eat. The variation which exists in the implementation of these programs suggests that the programs' effectiveness is lacking or is not clear. Recommendations based on the Community Health Practice Guideline methodology, the results of a critical review of the literature, the results of a survey of practices, and expert opinion were developed. The recommendations include: continuation of routine inspections at a frequency of one to two inspections per year per restaurant and the continuation of education programs. The evidence on which these recommendations are based is scant and more research is needed to ensure programs are needed, effective and efficient.

Lack of an association between endemic giardiasis and a drinking water source.

Waterborne outbreaks of giardiasis have been documented in many areas of North America associated with contaminated surface water supplies. The Greater Vancouver Water District (GVWD) administers the distribution of surface waters to 1.4 million people. We wished to determine if endemic giardiasis was associated with this water supply. One hundred and eighty cases, an equal number of laboratory (enteric) controls and 94 neighbourhood (friend) controls were interviewed by questionnaire. The cases and controls were similar in age, sex and community of residence. Risk factors for giardiasis included having a child under six in the house and travel, both in B.C. but outside of the GVWD, and in Africa, the Americas, south of the U.S. or Asia. The cases drank 3.6 cups of water per day, the enteric controls 3.5 and the friend controls 3.7. These amounts are similar to those reported ingested in outbreak studies. Water consumption was not a risk for endemic giardiasis.

Risk factors associated with echovirus 11' infection in a hospital nursery.

An outbreak of nosocomial echovirus 11' illness occurred between July 22 and August 12, 1983, infecting 14 infants in the nurseries at a hospital. Stool, throat or cerebrospinal fluid specimens for viral isolation were obtained from 142 and serum pairs from 98 of the 192 infants exposed to the nurseries during the outbreak. Infection was determined by isolation of virus from stool or cerebrospinal fluid and/or a 4-fold rise in neutralizing antibody to echovirus 11'. Eight infants were severely ill with seizures, pleocytosis or apnea; one infant died. Four infants were mildly ill; two were asymptomatic. Immune serum globulin, administered to all hospitalized infants on July 31, did not appear to attenuate echovirus 11' illness. Infants present in the Intermediate Care Unit greater than 48 hours were more likely to become infected than infants present less than or equal to 48 hours (attack rates, 25 and 3%, respectively). Among infants present in the Intermediate Care Unit, illness was associated with gavage feeding, mouth care and being a twin (P less than 0.05). These findings support the importance of good hygienic practices in preventing nosocomial viral infections.

Nystatin prophylaxis of fungal colonization and infection in granulocytopenic patients: correlation of colonization and clinical outcome.

Nystatin, one million units every four hours, was prospectively studied as a prophylactic antifungal agent in 164 neutropenic patients who were not initially colonized by fungi: 104 received nystatin and 60 served as controls. Fungal colonization occurred in 68/104 (65%) nystatin recipients and in 43/60 (71%) controls. However, nystatin significantly reduced multiple body site colonization and persistent oropharyngeal colonization. Despite these alterations in colonization profile, 16/104 (15%) nystatin recipients developed disseminated fungal infections, as compared to 5/60 (8%) control patients (0.5 greater than p greater than 0.1, N.S). Differences in the clinical course of colonized and non-colonized patients were observed. Eighteen of 111 (16%) colonized patients had afebrile clinical courses as compared to 16/53 (30%) non-colonized patients (p less than 0.05). Twenty-nine of 93 (31%) febrile episodes in colonized patients failed to respond to empiric antibiotic therapy as compared to 3/37 (8%) episodes in non-colonized patients (p less than 0.01). Disseminated fungal infections were diagnosed in 19/111 (17%) of colonized patients, as compared to 1/53 (2%) non-colonized patients (p less than 0.02). We conclude that colonized patients are more likely to develop febrile clinical courses, to fail to respond to empiric antibiotic therapy, and to develop disseminated fungal infection. Nystatin altered colonization patterns but did not prevent disseminated fungal infection.

Emergence of tobramycin-resistant S. epidermidis possessing aminoglycoside modifying enzymes and bacteremic superinfection during empiric therapy of febrile neutropenic episodes.

During a randomized clinical trial comparing tobramycin plus ticarcillin to netilmicin plus ticarcillin as empiric therapy of febrile neutropenic patients, Staphylococcus epidermidis emerged as the predominate superinfecting pathogen in tobramycin recipients. Overall clinical response was 68% (44/65 responding) in tobramycin/ticarcillin recipients and 73% (45/62) in netilmicin/ticarcillin recipients. However, 5/65 tobramycin/ticarcillin treated episodes were complicated by bacteremic superinfection with Staphylococcus epidermidis, as compared to 0/62 netilmicin/ticarcillin treated episodes (p less than 0.05). Four of the five bacteremic strains produced aminoglycoside adenylating enzyme ANT 4', 4''. Prior colonization of patients with identical strains was demonstrated by plasmid profile analysis, antibiograms and biotyping with the API Staph-Ident system. During the trial, 36 consecutive patients were studied for colonization patterns with coagulase-negative staphylococci. S. epidermidis accounted for 566/831 (68%) isolates of coagulase-negative staphylococci recovered from surveillance cultures. Tobramycin-resistant strains were acquired in 2/17, 4/12 and 9/14 patients during trimethoprim/sulfamethoxazole, netilmicin/ticarcillin and tobramycin/ticarcillin therapy, respectively. Prior to aminoglycoside therapy, 77% of strains were susceptible to less than or equal to 8 micrograms/ml of tobramycin, but only 35% and 28% were susceptible to tobramycin after initiation of tobramycin/ticarcillin and netilmicin/ticarcillin therapy, respectively. In contrast, greater than or equal to 93% of isolates were susceptible to netilmicin before and after aminoglycoside therapy. Absence of several sites susceptible to modification by aminoglycoside inactivating enzymes produced by staphylococci may give netilmicin a therapeutic advantage in the therapy of febrile neutropenic patients.

Randomized controlled trial comparing trimethoprim/sulfamethoxazole and trimethoprim for infection prophylaxis in hospitalized granulocytopenic patients.

The clinical and microbiologic efficacy of trimethoprim alone and trimethoprim/sulfamethoxazole for infection prevention was evaluated in 75 patients during 92 episodes of granulocytopenia. Ultimately, 60 patients were evaluable during 77 episodes of granulocytopenia, 36 episodes in the trimethoprim group and 41 episodes in the trimethoprim/sulfamethoxazole group. The incidence of infection was higher in the trimethoprim group (50 percent) than in the trimethoprim/sulfamethoxazole group (39 percent), but this did not reach statistical significance. Trimethoprim did not appear to be as protective as trimethoprim/sulfamethoxazole when the granulocyte count was less than 100/mm3. In patients receiving trimethoprim/sulfamethoxazole, aerobic gram-negative bacilli cleared from fecal surveillance cultures more often and new aerobic gram-negative bacilli were acquired less often than in those receiving trimethoprim alone (p less than 0.05). More myelosuppression was observed among patients receiving trimethoprim/sulfamethoxazole (p less than 0.001). These observations suggest that trimethoprim alone may not be optimal for preventing colonization and infection in granulocytopenic patients and that combination with other agents may be necessary to increase the spectrum of activity. Trimethoprim/sulfamethoxazole itself may predispose toward an increased risk of infection by prolonging myelosuppression.

Reduction in mortality from gram-negative sepsis in neutropenic patients receiving trimethoprim/sulfamethoxazole therapy.

The causes of death were reviewed in 53 patients from two prospective randomized trials on the efficacy of trimethoprim/sulfamethoxazole as prophylaxis of gram-negative bacillary infection in granulocytopenic patients. Twenty-nine deaths occurred in patients treated with TMP/SMX prophylaxis while 24 occurred in patients who served as controls in the first trial. The two groups were similar, with the exception that more patients in the TMP/SMX group had acute leukemia (82 versus 50%; P less than 0.02). Microbiologically documented gram-negative rod infection preceeded death in 8/24 control patients as compared to 2/29 TMP/SMX recipients (P less than 0.02). This decrease in gram-negative related deaths was most pronounced in the patients with acute leukemia. Fatal gram-negative rod infection occurred in 7/12 control leukemic patients as compared to 2/24 TMP/SMX treated patients. Despite the reduction in numbers of gram-negative rod-related deaths, infectious deaths accounted for 16/24 and 15/29 patients in control and TMP/SMX treated patients, respectively. Similar numbers of fungal, viral, and gram-positive bacterial infections occurred in each group. Fever with pulmonary infiltrates but without proven etilogic agents were included in the category of "clinically documented infections;" 6/7 patients with fever and undiagnosed pulmonary infiltrates were in the TMP/SMX group. Prophylactic administration or oral trimethoprim/sulfamethoxazole reduces the frequency of fatal gram-negative rod infections in neutropenic patients.

Respiratory and other responses in subjects immersed in cold water.

Subjects have been immersed in water at 27 degrees C and 10 degrees C and while immersed their respiratory rates, minute volumes, and end-tidal PCO2 levels were measured. Measurements were made with the subjects at rest, exercising at approximately 0.8 liter oxygen-min-1, and very vigorously at 1.8-2.0 liters oxygen-min-1. Immersion in the cold water caused an increase in respiratory rate and a fall in end-tidal PCO2. At the moderate rate of exercise the hyperventilation persisted in relation to the oxygen demand and there was still a significant reduction in end-tidal PCO2. At the greatest rates of exercise, the end-tidal PCO2 did not differ from that obtained in similar rates of exercise in warm water. Preheating the subject in a sauna so as to increase skin temperature, with minimal change in body temperature, greatly attenuated the ventilatory and end-tidal PCO2 responses to cold water immersion. The significance of these findings is discussed.