The risks of dental extraction during penicillin treatment

Endocarditis Caused by Highly Penicillin-Resistant Viridans Group Streptococci: Still Room for Vancomycin-Based Regimens

Optimal treatment options remain unknown for infective endocarditis (IE) caused by penicillin-resistant (PEN-R) viridans group streptococcal (VGS) strains. The aims of this study were to report two cases of highly PEN-R VGS IE, perform a literature review, and evaluate various antibiotic combinations in vitro and in vivo The following combinations were tested by time-kill studies and in the rabbit experimental endocarditis (EE) model: PEN-gentamicin, ceftriaxone-gentamicin, vancomycin-gentamicin, daptomycin-gentamicin, and daptomycin-ampicillin. Case 1 was caused by Streptococcus parasanguinis (PEN MIC, 4 μg/ml) and was treated with vancomycin plus cardiac surgery. Case 2 was caused by Streptococcus mitis (PEN MIC, 8 μg/ml) and was treated with 4 weeks of vancomycin plus gentamicin, followed by 2 weeks of vancomycin alone. Both patients were alive and relapse-free after ≥6 months follow-up. For the in vitro studies, except for daptomycin-ampicillin, all combinations demonstrated both synergy and bactericidal activity against the S. parasanguinis isolate. Only PEN-gentamicin, daptomycin-gentamicin, and daptomycin-ampicillin demonstrated both synergy and bactericidal activity against the S. mitis strain. Both strains developed high-level daptomycin resistance (HLDR) during daptomycin in vitro passage. In the EE studies, PEN alone failed to clear S. mitis from vegetations, while ceftriaxone and vancomycin were significantly more effective (P < 0.001). The combination of gentamicin with PEN or vancomycin increased bacterial eradication compared to that with the respective monotherapies. In summary, two patients with highly PEN-R VGS IE were cured using vancomycin-based therapy. In vivo, regimens of gentamicin plus either β-lactams or vancomycin were more active than their respective monotherapies. Further clinical studies are needed to confirm the role of vancomycin-based regimens for highly PEN-R VGS IE. The emergence of HLDR among these strains warrants caution in the use of daptomycin therapy for VGS IE.

Infective Endocarditis Due to Penicillin-Resistant Viridans Group Streptococci

BACKGROUND

The emergence of viridans group streptococci that are relatively or fully resistant to penicillin is increasingly being recognized worldwide, but only a scant number of penicillin-resistant isolates have been described as a cause of infective endocarditis. Because of the paucity of data, it has been difficult to define optimal treatment regimens for this syndrome. Thus, recommendations for therapy have largely been made on the basis of consensus opinion.

METHODS

We retrospectively identified a cohort of patients with infective endocarditis due to penicillin-resistant viridans group streptococci who were seen at the Mayo Clinic (Rochester, MN) between January 1967 and April 2006. Demographic characteristics, clinical features, treatment regimens, and outcomes were analyzed. Mean values are shown with standard deviations.

RESULTS

Twenty-nine patients were identified over the 38.5-year study period. Nineteen patients with native valve endocarditis were cured; 9 of these 19 patients received a 2.3+/-0.4-week antibiotic regimen consisting of penicillin and an aminoglycoside, and 8 of these 19 patients received treatment courses of 5.1+/-1.4 weeks' duration that consisted of either a bimodal combination regimen with a penicillin or ceftriaxone and an aminoglycoside or ceftriaxone monotherapy. Nine of 10 patients with prosthetic valve infection were cured with 4.1+/-0.6-week regimens that consisted of either a combination regimen or monotherapy with vancomycin or ceftriaxone. Mean duration of follow-up after hospital discharge was 9.1 years.

CONCLUSIONS

Outcomes of this relatively large population of patients with endocarditis with a prolonged duration of follow-up indicate that the application of current treatment guidelines should be successful in most patients.

Methods of testing combined antibiotic bactericidal action and the significance of the results

A DESCRIPTION IS GIVEN OF TWO METHODS OF MEASURING COMBINED ANTIBIOTIC BACTERICIDAL ACTION: a test in liquid medium with subculture and the cellophane transfer method. It is emphasized that information so obtained is necessary in order to predict the effect of combined treatment, particularly in bacterial endocarditis due to organisms not fully sensitive to penicillin. Eight case histories are given, in all of which such a prediction was fulfilled, one of failure and seven of success from the use of five different combinations. The cellophane transfer method was applied to the study of the nature of combined antibiotic action on multiple strains of several bacterial species. The results were rarely uniform for any given combination and species: the necessity for individual tests as a guide to treatment is thus confirmed.Modifications of the theory of combined action formulated by Jawetz are proposed.

The pregnancy outcome of acyanotic heart disease

OBJECTIVE

To study the pregnancy outcome of women with acyanotic heart disease.

METHOD

This is a retrospective study from a tertiary referral centre in a developing country over a period of 3 years.

RESULTS

There were a total of 19,151 deliveries where 143 cases had heart disease in pregnancy, all of which were acyanotic, giving an incidence of 0.7%. Fifty-one (38.4%) of these were congenital whereas 82 (61.6%) were acquired. There was no cyanotic heart lesion during this study period. The fetal and maternal outcome of the women with heart disease (study group) was compared with the general obstetric population in the Unit (control group) using the Chi-squared test. Ninety-two percent in the study group were asymptomatic (NYHA Class I). The age distribution were no different except in the < 20 years interval where there were significantly fewer in the study group. More women with heart disease were primiparous and fewer were multiparous as compared with the controls. There was no significant difference in the rate of induction of labour (9.8% vs 11.8%). The use of epidural analgesia was significantly higher in the study group (49% vs 13%) as was the instrumental delivery rates (35.7% vs 5.7%) when compared with the controls. The caesarean section rate was no different. The mean gestation of babies born to mothers with heart disease was 38.2 weeks. Significantly fewer babies were in the 3.0-3.5 kg weight interval and more in the 2.5-3.0 kg interval. However, this did not alter the perinatal mortality rates which was not significantly different (15.3 vs 14.0 per thousand).

CONCLUSION

The fetal and maternal outcome in women with acyanotic heart disease was favourable. It is advocated that the management of these cases should be multidisciplinary to optimise care for these patients.

BACTERIAL ENDOCARDITIS DUE TO AN ACTINOBACILLUS

A case of subacute bacterial endocarditis due to Actinobacillus actinomycetemcomitans followed dental extraction under penicillin cover. Isolation of the organism was only achieved by incubating blood cultures in a CO(2)-enriched atmosphere. The patient was successfully treated with streptomycin.

Prevalence of penicillin-resistant viridans streptococci in healthy children and in patients with malignant haematological disorders

The prevalence of penicillin-resistant viridans streptococci was studied in healthy children and in paediatric and adult patients with leukaemia to determine whether the frequent presence of penicillin-resistant streptococci in the oral cavity of children with leukaemia is the result of antibiotic therapy. Twenty of the oral swabs from 50 healthy children who had not received antibiotics in the three months prior to sampling yielded viridans streptococci that could be cultured on blood agar containing 2 micrograms/ml benzyl-penicillin. In 11 of the 20 cases the streptococci were resistant to penicillin (MIC > or = 4 micrograms/ml). This prevalence is significantly higher than that found in adult leukaemia patients (40% vs. < or = 5%) but is about the same as that found in paediatric patients with leukaemia. The high prevalence of penicillin-resistant streptococci in the paediatric age group should be considered when selecting therapy and prophylaxis, especially when the risk of infection with one of these cocci is enhanced.

The development of penicillin-resistant oral streptococci after repeated penicillin prophylaxis

Oral streptococci may cause infective endocarditis in patients with susceptible cardiac disease after dental treatment. Multiple dental visits, each preceded by penicillin prophylaxis, may result in the unwanted development of resistant oral streptococci. This study was undertaken to determine whether resistant oral streptococci would develop after the repeated use of penicillin prophylaxis in healthy adults. Plaque samples were collected from 20 subjects on each Monday for 5 successive weeks. Each subject was administered 2 gm penicillin V followed by 1 gm 6 hours later (standard prophylaxis regimen of the American Heart Association), on three successive Mondays (weeks 2, 3, and 4). The total cultivable oral streptococci and penicillin-resistant oral streptococci were determined for each plaque sample, and representative colonies of resistant streptococci were speciated. During the study, there was a significant increase in the number of subjects who harbored penicillin-resistant oral streptococci. However, with the exception of one subject who had resistant streptococci throughout the study, the number of resistant strains represented only 0.0003% to 0.41% of the total cultivable oral streptococci.

Bacterial endocarditis: a short overview

Bacterial (infective) endocarditis is a potentially fatal illness which may follow transient bacteremia induced by certain dental procedures. It is the purpose of this article to discuss the rationale behind the American Heart Association's current guidelines on antibiotic prophylaxis for this disease, to consider the dentist's role in implementing these recommendations, and to identify how the physician and dentist can act in the patient's best interests to prevent this illness.

Development of resistant oral viridans streptococci after administration of prophylactic antibiotics: time management in the dental treatment of patients susceptible to infective endocarditis

The American Heart Association recommends prophylactic administration of penicillin before each dental session to patients susceptible to infective endocarditis. Such preventive treatment, however, may trigger the transient appearance of penicillin-resistant bacterial strains. In order to investigate the behavior of oral streptococci, 29 healthy volunteers who did not harbor penicillin-resistant viridans streptococci received 4 gm of phenoxymethyl penicillin orally over a period of 10 hours. This amount constituted the sole dose of antibiotics administered in the entire experiment. Daily specimens of oral flora were obtained for 14 successive days from each participant and incubated aerobically with a penicillin-saturated disk for 24 hours. Viridans streptococci were considered resistant when bacterial colonies grew adjacent to the disk for 1 day or more. The study population was divided into high- and low-resistance groups, according to the individual antibiograms. Resistant viridans streptococci were already detected at 6 hours after penicillin ingestion in nine (31%) of the subjects. Six months later, oral specimens were taken from ten randomly selected participants; these specimens served as a control. The difference in bacterial resistance between the high- and low-resistance groups was significant for the duration of 9 days, as was that between the high-resistance and control groups (p less than 0.05 in both cases). In order to minimize the odds that penicillin-resistant bacterial strains will develop in patients susceptible to infective endocarditis, elective dental treatments in these persons should be scheduled in intervals of not less than 10 days.

A survey to evaluate the management of orthodontic patients with a history of rheumatic fever or congenital heart disease

A survey concerning the orthodontic management of patients with a history of rheumatic fever or congenital heart disease was mailed to a random sample of 500 orthodontists throughout the United States. Two hundred thirty-two surveys were completed and returned. Analysis revealed that 88% of the respondents were aware that they should screen for patients with a history of rheumatic fever or congenital heart disease, only 11% used the antibiotic regimen recommended in 1977 by the American Heart Association (see Fig. 2), one half of the respondents thought it was necessary to provide antibiotic coverage during banding, and 38% deemed it necessary for debanding procedures which were likely to cause some degree of bleeding from the gingival sulcus. Only one half of the respondents would discontinue treatment if a condition of gingivitis developed which did not show signs of improvement, and only 70% provided medication for orthodontic procedures that could result in bacteremia. Furthermore, the results of this survey indicated that there was a great variation in the antibiotic regimen of orthodontic treatment for patients at risk of developing endocarditis and that there was a need to make the orthodontist more aware of the 1977 recommendations of the American Heart Association. Finally, a comparison between the year of graduation from an orthodontic program and the number of respondents who did not screen for or did not premedicate at-risk patients revealed a direct relationship. The earlier the education, the smaller the number of respondents who screened or premedicated.(ABSTRACT TRUNCATED AT 250 WORDS)

Infective endocarditis: a review and update

Infective (bacterial) endocarditis has presented a "changing face" over the previous years but remains a disease with potentially serious complications. Surveys have indicated that up to 92% of cases of infective endocarditis could be attributed to a dental origin; yet most susceptible persons do not understand their condition or the precautions necessary prior to dental treatment. Up to 80% of infective endocarditis patients received no protection prior to dental or genitourinary manipulation. Dental practitioners, therefore, play an important role in the prevention of this disease and must be familiar with recent developments on the subject. This article provides an in-depth review of the disease and outlines and stresses the dental practitioner's responsibility in its prevention.

Pregnancy complicated by maternal heart disease at the National Maternity Hospital, Dublin, Ireland, 1969 to 1978

Three hundred eighty-seven pregnancies (295 patients) complicated by maternal heart disease, managed at the National Maternity Hospital, Dublin, Ireland, during the years 1969 to 1978, were reviewed. The incidence was 0.5%. Three hundred twenty-three (83.5%) were of rheumatic origin, 52 (13.4%) were congenital, and the remaining 12 (3.1%) were a miscellaneous group and included cases of cor pulmonale and coronary artery disease. There were two maternal deaths--one from congenital heart disease and one from postpartum suicide, unrelated to mild rheumatic heart disease. The perinatal mortality rate was 3.3%. Five pregnancies (three patients) were complicated by surgically uncorrected cyanotic congenital heart disease. One of the maternal deaths and three of the perinatal deaths occurred in this group. There were 38 episodes of cardiac failure (38 patients) in cases of rheumatic heart disease. The New York Heart Association grading was grade 1 in 15 (39%) of these before the onset of failure. Prophylactic antibiotics were not used and infective endocarditis did not occur. Therapeutic abortion was not practiced and a conservative approach was adopted in obstetric intervention and in all drug therapy.

Antibiotic prophylaxis against infective endocarditis after normal delivery--is it necessary?

During the years 1959 to 1978 inclusive 2165 women with rheumatic or congenital heart disease had vaginal deliveries at three large Dublin maternity hospitals. There were two (0.09%) cases of puerperal infective endocarditis, neither of which was unequivocally related to preceding childbirth during this period. Routine peripartum antibiotic prophylaxis was not given to either. A questionnaire of the practice of 19 obstetricians in Ireland showed that 12 (63%) gave antibiotics routinely during labour and after delivery in cardiac patients, five (26%) did not, and two (11%) used them occasionally. Peripheral vein blood was drawn serially from 0 to 30 minutes after vaginal delivery to determine the incidence of asymptomatic puerperal bacteraemia. A total of 299 cultures was obtained from 83 normal women and single blood cultures were positive in three women (3.6% of patients, 1.0% of cultures). A review of the published reports showed that well-documented cases of infective endocarditis and of asymptomatic puerperal bacteraemia after normal vaginal delivery are uncommon. There is evidence that antibiotic prophylaxis may increase the risk of developing antibiotic-resistant endocarditis. Recommended prophylactic regimens carry a considerable risk of drug toxicity. These facts, coupled with a lack of direct evidence in support of the efficacy of antibiotic prophylaxis, suggest that routine peripartum antibiotic prophylaxis is not indicated.

Effect of phenoxymethylpenicillin and clindamycin on the oral, throat and faecal microflora of man

Phenoxymethylpenicillin in capsules was given orally in doses of 800 mg twice daily for 7 days to 10 subjects. Saliva, throat and faecal specimens were taken up to 29 days for cultivation of aerobic and anaerobic bacteria. No changes in the normal flora in saliva, throat or faeces were noticed during the observation period. Clindamycin was given orally in doses of 150 mg 4 times daily to 10 other subjects. No changes in the aerobic oral flora were observed, while a significant decrease in the number of anaerobic bacteria occurred. In 2 volunteers, overgrowth of clindamycin-resistant clostridia were seen from days 4--16 in one and from days 2--7 in the other. The throat flora showed changes similar to the oral flora. Pronounced changes in the aerobic and anaerobic faecal bacterial flora occurred. Thus among the aerobes enterococci proliferated and among the anaerobes significant decreases in the number of cocci and gram-negative rods were noticed. In 4 subjects, clindamycin-resistant clostridia increased 4log. One of them developed diarrhoea and harboured an unidentified toxin-producing clostridial strain rather similar to Clostridium difficile.

Nitroblue tetrazolium and Limulus assays for bacteremia after dental extraction: effect of topical antiseptics

Bacteremia that occurs after dental extraction is common. This study assessed the effect of topical antisepsis on the incidence and magnitude of post-extraction bacteremia. On hundred patients scheduled for elective tooth extraction were randomized among four groups: contr-l, mouthrinsing with sodium-p-toluene sulfonchloramide (chloramine-T), toothbrushing with chloramine-T, and irrigation with Lugol's solution. The results showed that 84% of the control group and 59% of the treatment groups had positive blood cultures (290 organisms isolated) after dental extraction. The duration and magnitude of these bacteremias were diminutive as documented by the six serial blood cultures taken for each patient, colony counts per milliliter of blood, and nitroblue tetrazolium and Limulus assays. Brushing the teeth or rinsing the mouth with chloramine-T before dental extraction significantly reduced the incidence of bacteremia (P less than .025) and the number of different organisms recovered from each patient (P less than .05). Thus, topical treatment with chloramine-T is a simple and effective means of reducing the incidence of postextraction bacteremia.

Concentration of azidocillin, erythromycin, doxycycline and clindamycin in dental alveolar serum after single oral doses

Treatment of osteitis in the mandible after surgery is still a clinical problem. Levels of four antibiotics--azidocillin, erythromycin, doxycycline, and clindamycin--were measured in serum and dental alveolar serum in 42 patients undergoing oral surgery. The systemic serum concentrations were higher than the dental alveolar serum concentrations in all patients. The maximal concentration in the alveolar serum for azidocillin was 6.0-12.0 microng/ml, for erythromycin 0.7-1.3 microng/ml, for doxycycline 2.8-3.6 microng/ml, and for clindamycin 2.0-2.8 microng/ml. When the dental alveolar serum concentrations of the various antibiotics were related to their range of inhibitory concentrations for microorganisms isolated from mandibular osteitis, it was noticed that each drug achieved levels sufficient to inhibit most strains.

The "incubation period" of subacute bacterial endocarditis

In an attempt to gain information about the "incubation period" of subacute bacterial endocarditis, the literature was searched for case reports stating a specific interval between an event likely to cause bacteremia and the onset of symptoms. In 76 cases of streptococcal endocarditis for which this information was given, the median "incubation period" was one week. Symptoms began within two weeks in 64 of these cases (84%). Although there may be a bias toward reporting short incubation periods, it is concluded that the incubation period of subacute bacterial endocarditis is often shorter than is generally realized, and that procedures carried out more than two weeks before onset of symptoms are less likely to be causally related. In postcardiotomy cases, where timing of the bacteremia causing endocarditis is less easy to define, 27% of 122 cases of staphylococcal endocarditis developed within two weeks of surgery. This information is relevant to the planning and evaluation of prophylactic chemotherapy against bacterial endocarditis.

Current practice in prevention of bacterial endocarditis

A survey of Oxfordshire dentists showed that most practise prophlaxis of bacterial endocarditis, but that few follow currently recommended regimens. for example, prophylactic antibiotics are started one or more days before the procedure by 72 per cent of dentists, and two or more days before by 25 per cent. Eight-seven per cent administer antibiotics for a total of four or more days. Penicillin is most often given, but tetracyline remains the commonest second choice. Only 12 per cent use intramuscular drugs as first choice, and procaine penicillin is seldom used. These practices are contrasted with current medical recommendations and discussed with reference to fresh experimental evidence on prevention of bacterial endocarditis.

Prosthetic valvular endocarditis. A 12-year review

A retrospective examination was made of a total of 48 patients with infected prosthetic cardiac valves implanted in 1,236 patients during 1960-1972. Survival rate of the valvular infections was 40%. The purpose of the study was to determine the factors which aided or decreased patient survival and to develop a program of treatment with antimicrobial agents. Numerous antimicrobics and a variety of dosage schedules were used. Of 19 surviving patients, medical treatment alone was effective in 14, despite the continued presence of a valvular prosthesis. Reoperation was successful in five of nine patients. Lifelong chemoprophylactic or suppressive therapy was shown to be unnecessary to prevent relapse in 12 survivors. Prompt surgical replacement is indicated if antimicrobial therapy fails to eradicate infection of a prosthetic valve. A more systematic approach to antimicrobial therapy should improve survival of medically treated infections. Recommendations are made for prevention and treatment of prosthetic valvular endocarditis.

Chemotherapy of experimental streptococcal endocarditis. I. Comparison of commonly recommended prophylactic regimens

The effectiveness of various antibiotics commonly recommended for the prophylaxis of bacterial endocarditis has been evaluated in experimental streptococcal endocarditis in rabbits. High doses of penicillin G did not prevent the development of this infection. The only consistently successful prophylactic regimens using penicillin alone were those which provided for both an early high serum level and more than 9 h of effective antimicrobial action. Vancomycin was the only other drug which proved uniformly successful when given alone, even though the duration of its antimicrobial action in the blood was only 3 h. However, combined therapy using penicillin G or ampicillin with streptomycin was always effective in prophylaxis. Treatment with single injections of ampicillin, cephaloridine, cephalexin, clindamycin, cotrimoxazole, rifampicin, streptomycin, erythromycin, and tetracycline failed to prevent infection. The findings provide information on the effect of antimicrobials in vivo and may be applicable to the chemoprophylaxis of infective endocarditis in clinical practice.