Markers for implant placement in CBCT: a technical overview.

Cone beam computer tomography (CBCT) is becoming a more accessible modality of imaging within dentistry. It has particular application in the diagnostic treatment planning for dental implant placement. The use of radiographic surgical stents with CBCT can help to provide important information about bone position and therefore placement of implants and final restorations. This article looks at a novel technique, which allows a variety of different marker positions that can be quickly and easily placed and removed. It allows the use of a current prosthesis that can be adapted to act as a surgical stent during CBCT.

An outbreak of Shigella dysenteriae type 2 among laboratory workers due to intentional food contamination.

CONTEXT: Shigella dysenteriae type 2 is rare in the United States, and outbreaks associated with this pathogen are uncommon. OBJECTIVE: To determine the magnitude and source of an outbreak of S dysenteriae type 2. DESIGN: Retrospective cohort. SETTING: Laboratory of a large medical center. PATIENTS: Case patients were identified as laboratory workers who had diarrhea on or after October 28 and a positive stool culture or temperature greater than 37.8 degrees C. Laboratory workers with diarrhea only were probable case patients. MAIN OUTCOME MEASURES: We interviewed laboratory staff and performed identification, serotyping, and pulsed-field gel electrophoresis on isolates from case patients, implicated food, and laboratory stock culture. RESULTS: From October 29 through November 1, a total of 12 (27%) of 45 laboratory staff developed severe, acute diarrheal illness; 8 had S dysenteriae isolated from stool and 4 were hospitalized. All case patients reported having eaten muffins or doughnuts placed in the staff break room on October 29. Pulsed-field gel electrophoresis showed stool isolates from 9 case patients were indistinguishable from S dysenteriae type 2 recovered from an uneaten muffin and from the laboratory's stock strain, a portion of which was missing. CONCLUSIONS: The source of the outbreak was most likely the laboratory's stock culture, which was used to contaminate the pastries. Results of this investigation underscore the need for adequate precautions to prevent inadvertent or intentional contamination from highly pathogenic laboratory specimens.

Use of Texas birth certificate data to predict measles immunization status.

Inadequate immunization has been a major cause of epidemic measles, but risk factors for inadequate immunization are poorly characterized. By using measles data bases and computerized birth certificate files, we identified a retrospective cohort of 1,070 Texas-born children who were aged 15 months to 10 years when they had measles during the 1988 to 1991 epidemics. We used measles and birth certificate data, including prenatal care and demographic information, to determine immunization status and risk factors for inadequate measles immunization. Risk factors predicting lack of immunization in children with measles in stepwise logistic regression were black ethnicity, urban residence, poor prenatal care, preschool age, and an unknown father. Birth certificates contain information that can predict inadequate measles vaccination and should be evaluated prospectively.

Initial STD visits by adolescent females, Dallas County, Texas.

Sexually active adolescents are at high risk for unintended pregnancy and sexually transmitted diseases. We identified a cohort of 6089 women aged 13 to 21 years who in 1985 either delivered an infant at Parkland Hospital (3154) or used the outpatient clinics (2935). We reviewed those records and others in the Dallas County sexually transmitted disease (STD) clinic for the period 1983 through 1988 to determine the prevalence of visits to the Dallas County STD clinic by pregnant and nonpregnant adolescents, STD diagnoses at initial visit, whether STD visits and diagnoses varied by pregnancy status or ethnic background, and how the women were referred to the STD clinic. Similar percentages of nonpregnant (13%) and pregnant (11%) women had an STD visit, and most adolescents who visited the STD clinic had an STD diagnosis made. Gonorrhea and syphilis were the STDs diagnosed most frequently in both pregnant and nonpregnant adolescents. Regardless of pregnancy status, black adolescents were 7.3 times more likely to have an STD visit. Referral by a sexual partner was the second most common reason that adolescents sought STD care. Our study provides only minimal estimates of STDs among adolescents but indicates STDs, regardless of pregnancy status, are a more common medical problem than has been reported previously. Referral by sexual partners may be an important way to reach adolescents at risk for STDs.

Changing immunization referral patterns among pediatricians and family practice physicians, Dallas County, Texas, 1988.

Family practice physicians and pediatricians in Dallas County, Texas, were surveyed to determine how recent vaccine price increases have changed immunization referral patterns. A total of 73% of responding physicians referred some pediatric patients for immunization in 1988. Public health clinics were the largest referral source with more responding pediatricians (84.4%) referring patients than did responding family practitioners (66.5%). Referrals to the clinics were most often made when patients were unable to afford immunizations in a private practice setting. Between 1979 and 1988, the number of responding pediatricians and family practitioners making immunization referrals increased by 193% and 391%, respectively. The percentages of children referred for immunization increased by 693% during the same decade. It was suggested by our survey of Dallas County physicians that a new influx of patients are using public sector immunizations, potentially creating additional financial stress for public health programs. In addition, this shift to the public sector may undermine the health departments' ability to provide new vaccines or protect greater numbers of children with immunization.

Tuberculosis epidemic among hospital personnel.

Six employees of the emergency department at Parkland Memorial Hospital developed active tuberculosis in 1983-1984. Five of the cases occurred four to 12 months after exposure to the index case, a patient with severe cavitary tuberculosis seen in the emergency department in April 1983. One resident physician developed cavitary disease after exposure to this patient. An additional employee case may have resulted from transmission from one of the initial employee cases. One immunocompromised patient may have acquired tuberculosis as a result of exposure to the index case. In addition, the tuberculin skin tests of at least 47 employees exposed to the index case converted from negative to positive. Of 112 previously tuberculin-negative emergency department employees who were tested in October 1983, 16 developed positive skin tests, including the 5 employees with active disease. Fifteen of these new positives had worked on April 7, 1983, while the index case was in the emergency department (X2 = 20.6, P less than 0.001). Factors related to the genesis of the epidemic included the disease characteristics in the index case and the recirculation of air in the emergency department. This investigation indicates that city-county hospital emergency department employees should be screened at least twice a year for evidence of tuberculosis and that the employee health services of such hospitals should regard the surveillance of tuberculosis infection among personnel at a high-priority level.

Neonatal intensive care unit bacteremia: emergence of gram-positive bacteria as major pathogens.

An outbreak of nosocomial Staphylococcus epidermidis bacteremia in a neonatal intensive care unit in 1981 was epidemiologically linked to use of Broviac central venous catheters (p = 0.05) and prompted a review of nosocomial infection surveillance data for the previous 6 years, which indicated a striking shift from gram-negative to gram-positive bacteria, especially coagulase-negative staphylococci, as major bloodstream pathogens. In a case-control study with 68 patients with bacteremia between 1979 and September 1981 and 64 control patients, stratified by birth weight, three risk factors were identified: use of Broviac central venous catheters, surgical procedures, and intravenous hyperalimentation. The risk factors varied with the birth weight category. In the group of cases and controls with birth weights less than 1500 gm, only the use of Broviac catheters, which are usually left in the superior vena cava for several weeks, was associated with subsequent bacteremia (odds ratio = 7.1, p = 0.001). These observations, as well as the temporal association of the introduction of Broviac catheters with the subsequent shifts in causes to gram-positive organisms, suggest that the long-term indwelling vascular access devices contributed greatly to the changing pattern.

Campers' diarrhea outbreak traced to water-sewage link.

From June through September 1979, diarrheal illness occurred in an estimated 1,850 persons who had camped at a private campground in Arizona. Illness occurred more frequently among campers at that campground than among those in the adjacent State park (P less than 0.0001). The same well served both the private and the State campgrounds as the source of drinking water, but that water was distributed to the two campgrounds through separate lines. Illness was significantly associated with drinking water at the campsite (P less than 0.0001), drinking larger quantities of campsite water (P less than 0.001), and camping on the southwest side of the campground (P less than 0.001). Samples of the water collected from the system during January through June contained no coliform bacteria. However, all those samples had been collected from the State park only. Of the 11 water samples submitted for bacteriological analyses during the summer, 3 had high levels of bacteria. Excavation of the water system uncovered a direct cross connection between the potable water system and a sewage-effluent irrigation system. This outbreak calls attention to the importance of designing, maintaining, and monitoring potable water systems properly, especially those proximate to wastewater re-use systems.

Bactericidal activity of antiseptics against methicillin-resistant Staphylococcus aureus.

Various commonly used antiseptics were tested against three strains of methicillin-resistant Staphylococcus aureus (MRSA) at stock strength and in serial 10-fold dilutions. The stock solutions of 4% chlorhexidine gluconate-alcohol (Hibiclens), 1% p-chloro-m-xylenol (Acute-Kare), and 3% hexachlorophene (Phisohex) produced 2-log reductions of MRSA after a 15-s exposure, but even after 240 s, these solutions failed to kill all the MRSA. Povidone-iodine (Betadine) solution was maximally effective at the 1:100 dilution, killing all the MRSA within 15 s; other dilutions were less effective, though each killed the MRSA within 120 s. Similar results were obtained with three different strains of methicillin-susceptible S. aureus. Thus, of the four most commonly used antiseptics, povidone-iodine, when diluted 1:100, was the most rapidly bactericidal against both MRSA and methicillin-susceptible S. aureus.

Predisposition for cholera of individuals with O blood group. Possible evolutionary significance.

At the Matlab Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh, the authors examined the blood groups of patients hospitalized between January and September 1979 for diarrheal disease due to a variety of bacterial and viral agents. A significant association was identified only for cholera, in which cholera patients were twice as likely to have blood group O and one-ninth as likely to have blood group AB as community controls. A follow-up study of family contacts of cholera patients, carried out between September 1980 and July 1982, indicated that blood group did not affect an individual's risk of having a culture-proven infection with V. cholerae 01 but was directly related to the severity of disease. Individuals with the most severe diarrhea compared with those with asymptomatic infection were more often of blood group O (68% versus 36%, p less than 0.01) and less often of AB (0% versus 7%, p less than 0.01). It was not possible to identify the molecular basis for this genetically related protection using biologic models of cholera that are currently available. The constant selective pressure of cholera against people of O blood group may account in part for the extremely low prevalence of O group genes and the high prevalence of B group genes found among the people living in the Gangetic Delta.

Catheter-associated bacteriuria. Failure to reduce attack rates using periodic instillations of a disinfectant into urinary drainage systems.

We assessed the efficacy of periodic instillations of hydrogen peroxide into urinary drainage systems in the prevention of catheter-associated bacteriuria in a prospective and randomized clinical study of 668 patients with indwelling urethral catheters. Bacteriuria was documented in 68 (10%) of the 668 patients after a mean duration of four days of catheterization. There was no difference between the hydrogen peroxide group and the control group in the mean duration of catheterization before the onset of bacteriuria, in the attack rate for bacteriuria, or in the spectrum of etiologic agents recovered. Bag contamination with the same organism responsible for bacteriuria preceded infection in only five (7%) of the 68 patients, three patients using hydrogen peroxide and two in the control group. We conclude that infections arising intraluminally from contamination of the drainage bag are uncommon among catheterized patients and that the periodic instillation of disinfectants into closed sterile drainage systems is not effective in reducing the incidence of catheter-associated bacteriuria.

A 27-nm virus isolated during an outbreak of acute infectious nonbacterial gastroenteritis in a convalescent hospital: a possible new serotype.

An outbreak of acute infectious nonbacterial gastroenteritis began among elderly patients in a convalescent hospital in Marin County in northern California in March 1978 and persisted through May 1978. The overall clinical attack rate was 51% of 187 residents and 12% of 180 employees. A 27-nm viruslike particle was observed by immune electron microscopy in stools obtained at or near the onset of illness from four of 32 patients. Seroresponses to the 27-nm particles were found by immune electron microscopy in 16 of 18 patients. In addition, serologic evidence of infection with this or a related agent was demonstrated in persons who developed illness in another large outbreak of acute infectious nonbacterial gastroenteritis which occurred in a nearby county. This agent is morphologically similar to but serologically unrelated to the Norwalk and Hawaii gastroenteritis agents and has been designated the Marin agent pending further classification.

Nosocomial Legionnaires' disease: a continuing common-source epidemic at Wadsworth Medical Center.

Forty-nine cases of Legionnaires' disease were identified from May 1977 through July 1978 in patients and employees at Wadsworth Medical Center. Cases clustered in October and November 1977. Fifteen patients died. All Legionnaires' disease (LD) patients were in the hospital before onset of illness (median time from admission to onset, 17 days; range, 3 to 276 days). Twenty patients were immunosuppressed or compromised by malignancy. In 1977, six of 12 renal-homograft recipients acquired LD pneumonia in contrast to three of 22 during the preceding 3 years (P = 0.031, Fisher's exact test). In a prospective survey of 1658 consecutive hospital admissions, seven cases of Legionnaires' diseases occurred (0.4%), including six among 14 patients who seroconverted to the LD bacterium. Prevalence of a reciprocal titer of 128 or above in Wadsworth employees was significantly greater than in a nearby control population (P = 0.044, Fisher's exact test). Exposure to the external hospital environment may be an important factor, and soil may be a reservoir for the LD bacterium. Legionnaires' disease at Wadsworth may be a nosocomial pneumonia affecting a small group of patients with particular risk factors.

Legionnaires' disease in renal-transplant recipients.

Legionnaires' disease is reported in five renal-transplant recipients. All had febrile respiratory illnesses with pulmonary infiltrates and one died. The diagnosis was made on clinical features and by indirect fluorescent antibody titres. Symptoms started after maximum immunosuppressive therapy.