Hospital practices influence the pattern of infective endocarditis

OBJECTIVE: To identify factors contributing to infective endocarditis at a major teaching hospital. METHODS: Retrospective review of clinical records of patients diagnosed with endocarditis by standard case definitions with respect to causative organisms, clinical features and outcome. RESULTS: One hundred and ninety-three episodes of endocarditis seen between 1979 and 1992 at Westmead Hospital, Sydney, were reviewed. In the 174 cases where the causative organism was isolated, 75 (43%) were Staphylococcus aureus and 50 (29%) were viridans streptococci. Nosocomial acquisition and/or inter-hospital transfer accounted for 83 episodes; 48 (58%) S. aureus (P < 0.001) and nine (11%) viridans streptococci (P < 0.001). In cases from the local community, viridans streptococci were more common than S. aureus (37% versus 25%); these included 18 episodes (14 S. aureus) in intravenous drug users. CONCLUSION: We conclude that, compared with community-acquired infections, the aetiology of endocarditis in a large teaching hospital is influenced strongly by the prevalence of nosocomial endocarditis and the need for interhospital transfer of complicated cases.     

Activation of the alternate complement pathway in Staph. aureus infective endocarditis and its relationship to thrombocytopenia, coagulation abnormalities, and acute glomerulonephritis

Twenty-four patients with infective endocarditis (IE) are described, fourteen with Staph. aureus and ten with other organisms. Despite the acute nature of the infection, ten of the fourteen with Staph. aureus IE were hypocomplementaemic; six of these ten had normal levels of C4 associated with low C3 levels, suggesting activation of the alternate complement pathway. Factor B (C3PA) was also low in three of these six cases. In the ten patients with non-Staph. IE, three had hypocomplementaemia with low levels of C4, C3, and Factor B, probably due to C1 (classical pathway) activation with feedback activation of the alternate pathway. In addition, thrombocytopenia was noted in nine of the twenty-four patients and was associated with hypocomplementaemia; the degree of renal insufficiency noted in these patients also correlated with hypocomplementaemia. In Staph. aureus IE thrombocytopenia and hypocomplementaemia, occurring early in the course of the disease, may be due to a non-immune interaction of Staph. cell wall products (Protein A) with immunoglobulin, complement components, and thrombocytes.     

Characteristics of the staphylococci isolated from the udder of cows with mastitis

A total of 175 strains of Staphylococcus aureus and 67 strains of Staphylococcus epidermidis were studied, isolated from 486 samples of milk secretion taken aceptically from the individual quarters of the udder of cows affected with subclinical and purulent (clinical) mastitis. The staphylococci were referred to as the causative agent of mastitis in case they were the only microflora in the seedings of the investigated material. Tests were applied as given in Fig. 1 to characterize the strains. It was found that mastitis in cows could be due to both plasma coagulating staphylococci (Staphylococcus aureus) and coagulase-negative Staphylococcus epidermidis organisms. The two Staphylococcus species were isolated from cows with clinical and subclinical mastitis. The division between pathogenic and nonpathogenic Staphylococcus strains by the plasma-coagulating symptom proved impossible, and this made it necessary to use other tests for pathogenicity. It became evident that the thing Staph. aureus and Staph. epidermidis had in common when isolated from cows with mastitis was the production of a gold-like pigment and delta hemolysin. Similarly to Staph. aureus isolated animals, the bovine Staph. epidermidis organisms did not possess fibrinolysin and rarely produced hemolysin. The isolated organisms belonging to the coagulase-positive staphylococci corresponded by their basic properties to Staphylococcus aureus var. bovis as described in the literature. The cultures of Staphylococcus epidermidis isolated under similar conditions showed in a considerable per cent of the cases somewhat different behaviour.     

Development of animal models for the chronobiotics of melatonin analogs

We reviewed the records of patients admitted to our centre with the diagnosis of isolated tricuspid valve infective endocarditis and analysed the clinical presentation, etiopathogenic agent, echocardiographic features and therapeutic approach, namely the indication for cardiac surgery. Between 1988 and 1996, 11 cases of confirmed tricuspid valve endocarditis were identified, corresponding to 5% of the cases of endocarditis admitted to our centre in the same period. A predisposing factor was found in ten of the patients, half of them intravenous drug addicts and Staphylococcus aureus was the most frequent agent isolated. Fever and pleuro-pulmonary manifestations were predominant clinical features. Transthoracic echocardiography had a crucial role in the diagnosis and transesophageal echocardiography was important to characterize vegetations. Four patients underwent cardiac surgery, for persistent infection. In two cases, excision of the vegetations and ring annuloplasty was performed. In two patients not addicted to drugs, the tricuspid valve was replaced with a bioprosthesis, since the extension of the damage to the valve did not allow repair. One patient, with early endocarditis of a tricuspid bioprosthesis died before surgery was attempted.     

Why is there an analytical culture in a medical laboratory?]

During a seven-year period (1998-94) 68 patients with infectious endocarditis were diagnosed at a university hospital. Staphylococcus aureus was the most common etiological agent (38%), followed by Streptococcus viridans (21%). In seven patients the diagnosis infectious endocarditis was first made during autopsy, all seven of them had the clinical diagnosis septicaemia. Surgery was performed on 41% of the patients. Case fatality was 34%. Case fatality was significantly higher for S aureus endocarditis than for S viridans endocarditis, 48% vs. 7% (p = 0.01). The advantages of transthoracic and transoesophageal echocardiography in the diagnosis and follow up of patients with infectious endocarditis is emphasized. In spite of these new diagnostic tools a definitive clinical diagnosis of infectious endocarditis was not made for 23% of the patients.     

Physiopathology of leg ulcers]

Polymicrobial endocarditis (PE) is uncommon, whether in series of cases of polymicrobial bacteriemia or of endocarditis. Among the 201 cases of infective endocarditis seen between 1986 and 1995 by an infectious diseases service, 12 patients had PE (6%). Nine were males, mean age was 28 years and ten were active intravenous drug users. All of them were HIV (+) and 50% had AIDS. Eleven subjects had infection of the tricuspid valve and 58% developed septic pulmonary emboli. The most common organism encountered was Staphylococcus aureus in 8 patients followed by Streptococcus viridans and S. pneumoniae in three. The most common combinations of organisms were S. aureus and S. pneumoniae in 3 cases and S. aureus and Pseudomonas aeruginosa in two. Two patients died, one with Xantomona maltophilia and another with Candida albicans. The symptoms of PE were usually indistinguishable from endocarditis caused by a single organism and the prognosis depended on the species rather than the number of organisms isolated.     

Time-frequency analysis of heart murmurs. Part II: Optimisation of time-frequency representations and performance evaluation

OBJECTIVE: We hypothesized that carriage of Staphylococcus aureus among continuous ambulatory peritoneal dialysis (CAPD) patients was influenced by their spouses. Furthermore, this carrier status was compared to previous Staph. aureus peritonitis episodes in order to identify the influence of Staph. aureus carriage on peritonitis rate. DESIGN: A combined prospective surveillance study (Staph. aureus carriage) and retrospective chart review (Staph. aureus peritonitis). SETTING: A single peritoneal dialysis unit in a county hospital. PATIENTS AND METHODS: Cultures from patients (n = 32) and spouses (n = 16) were obtained twice, with a 1-month interval, from the anterior nares, the umbilical, and one groin area. All positive cultures were phage typed. Retrospective chart review of all episodes of Staph. aureus peritonitis among the patients was carried out. RESULTS: Twelve of 32 patients (37.5%) and 5 of 16 spouses (31%) evaluated were carriers. Half of the spouses of patients who were Staph. aureus carriers, were also carriers, as opposed to 20% of spouses of noncarrier patients (p = 0.30). Patients and spouses always shared the same phage type. Among patients, Staph. aureus was found in the nose only (n = 9), in all three regions (n = 2), and extranasally only (n = 1). If only one nasal culture was used to establish carriage, the sensitivity and negative predictive value would be 92% and 95%, respectively. A trend toward a higher incidence (p = 0.062) of Staph. aureus peritonitis was found among carriers (patients), 0.37 versus 0.28 peritonitis episode/dialysis-year. CONCLUSIONS: Only one positive nasal culture was necessary when carriage of Staph. aureus was to be established. Staph. aureus carriage was found more often in patients who had previously suffered from Staph. aureus peritonitis. The phage types isolated remained fairly constant, and the patients and spouses often had the same carrier state and shared the same phage types, although transmission does not always take place.     

Sex differences in occupational performance

Nineteen patients with cystic fibrosis were seen in the I Department of Tuberculosis and Lung Diseases during 3.5 years. There were 12 (63%) female, and 7 male, aged from 16 to 35 years (mean 23.2). Most patients were diagnosed in childhood, but 4 were diagnosed in their early adulthood. The diagnosis was confirmed by positive chloride sweat test in all cases. Molecular DNA analyses were performed in 16 cases. In 9 (56%) cases two mutations in the CFTR gene were identified. In 5 cases one mutation was identified. All patients had bronchiectases confirmed by CT. Spirometry showed lung function impairment with predominantly obstructive pattern. Mean VC was 2.57l, mean FEVI was 1.66l. In 7 (37%) cases FEVI was lower then 30% of predictive value. Hypoxemia was found in 11 (58%) cases and hypercapnia in 3 (16%) cases. Sputum cultures were positive for mucoid P. aeruginosa in 12 (63%) cases, for Staph. aureus in 16 (84%) cases. Persistent colonisation with nontuberculous mycobacteria was found in 2 (10.5%) cases. Aspergillus fumigatus was identified in sputum cultures in 2 subjects who had also positive precipitation test. Diabetes mellitus was diagnosed in 2 cases. Meconium ileus equivalent was seen in 1 case. Pneumothorax was seen in 1 case. One patient died in the endstage of the illness.     

Pyogenic liver abscesses and acute schistosomiasis mansoni: report on 3 cases and experimental study

Three children with acute schistosomiasis mansoni developed pyogenic liver abscesses. The abscesses were diagnosed by ultrasonography and confirmed during laparotomy. Staphylococcus aureus were the sole bacteria isolated from the abscesses. An experimental study was carried out in mice to establish whether schistosomiasis is a predisposing cause for pyogenic liver abscesses. Seventeen mice (group 1) were infected with 40 Schistosoma mansoni cercariae (LE strain) and 60 d later inoculated intravenously with a strain of Staph. aureus, isolated from a patient with bacteraemia; 17 mice infected with Sch. mansoni (group 2), 19 infected with bacteria alone (group 3), and 18 uninfected mice (group 4), served as controls. Thirteen group 1 mice (77%) developed multiple liver abscesses while none was observed in the controls. These results indicate that acute schistosomiasis mansoni concurrent with Staph. aureus bacteraemia favours the colonization of the liver by bacteria and the development of pyogenic hepatic abscesses.     

Are the Duke criteria superior to the Beth Israel criteria for the diagnosis of infective endocarditis in children?

Accurate diagnosis of infective endocarditis may be difficult. The Beth Israel criteria and the newer Duke criteria assign probability to the diagnosis of infective endocarditis on the basis of the presence of common features and manifestations. We reviewed 111 cases of pediatric infective endocarditis diagnosed and treated over 19 years. Each case was classified by the two criteria, and the results were compared. Of 111 cases, 73 (66%) and 18 (16%) were classified as definite by the Duke criteria and the Beth Israel criteria, respectively. No cases were rejected by the Duke criteria, while 21 (19%) of 111 were rejected by the Beth Israel criteria. In 18 pathologically proven cases, reanalysis without pathological data showed that the Duke criteria had significantly greater sensitivity (83%) than the Beth Israel criteria (67%) (P < .03). Echocardiographic evidence was required in 22 cases for definite classification by the Duke criteria; none were rejected, however, when echocardiographic findings were ignored. Our results suggest that the Duke criteria are superior to the Beth Israel criteria for the diagnosis of pediatric infective endocarditis.     

Growth and enterotoxin production of Staphylococcus aureus during the manufacture and ripening of Camembert-type cheeses from raw goats' milk

Tests were carried out to determine the effect of manufacturing procedures for a Camembert-type cheese from raw goats' milk on the growth and survival of Staphylococcus aureus organisms added to milk at the start of the process, and to study the possible presence of staphylococcal enterotoxin A in these cheeses. The initial staphylococcal counts were, respectively, 2, 3, 4, 5 and 6 log cfu ml-1. Cheese was prepared following the industrial specifications and ripened for 41 d. Detection of enterotoxins was done by the Vidas SET test and by an indirect double-sandwich ELISA technique using antienterotoxin monoclonal antibodies. Generally, numbers of microbes increased at a similar rate during manufacture in all cheeses until salting. During the ripening period, the aerobic plate count population and Staph. aureus levels remained stable and high. There was an approximately 1 log reduction of Staph. aureus in cheeses made with an initial inoculum of Staph. aureus greater than 10(3) cfu ml-1 at the end of the ripening period (41 d) compared with the count at 22 h. The level of staphylococcal enterotoxin A recovered varied from 1 to 3.2 ng g-1 of cheese made with an initial population of 10(3)-10(6) cfu ml-1. No trace of enterotoxin A was detected in cheeses made with the lowest Staph. aureus inoculum used in this study.     

Relationship between thickness, chapping and Staphylococcus aureus colonization of bovine teat tissue

Post-milking measurements of teat skin chapping score, teat thickness and colonization by Staphylococcus aureus were determined for 11.5 d. Three teats on each of twelve Holstein cows, free from Staph. aureus intramammary infections, were immersed in 1 M-NaOH solution to induce teat chapping; the fourth teat served as a control. To achieve different degrees of chapping, one teat per cow received one immersion after each milking for three consecutive milking periods, a second teat received two immersions, and the third teat received one immersion which coincided with the last immersion of the other two teats. All teats were challenged twice with a skim milk broth culture of Staph. aureus (5 x 10(6) cfu) after the first and second milking following NaOH treatment. Measures were initiated with the milking following the last Staph. aureus challenges. Tissue thickness of the lateral side of the teat (barrel) and colonization by Staph. aureus declined with time. Thickness of the teat end varied more erratically. Teat skin chapping score was positively correlated (P < 0.001) with tissue thickness of the barrel and Staph. aureus colonization. Thickness of the barrel was not significantly correlated with Staph. aureus colonization. Barrel thickness as a covariate had a significant effect (P < 0.05) on teat skin colonization of Staph. aureus, whereas teat skin score and teat end thickness had no significant effect. Thus, thickness of the lateral side of the teat explained the greatest variation in Staph. aureus teat skin colonization in the model tested.     

Epidemiological changes in infectious endocarditis. A prospective study, 1992-96

BACKGROUND: To know the present epidemiological situation of the infective endocarditis in our environment and its evolution in the last few years. RESULTS: The incidence of infective endocarditis was 0.85 per thousand patients admitted to hospital, with a mean age of 43 years. The predisposed factors more frequently found were: drug addiction (32%) and cardiac prosthetic valves (23%). In the greatest number of our patients the cardiac valves involved were: tricuspid (28%), mitral (27%) and prosthetic valves (23%). The causative organism were: S. aureus (19 cases), Streptococcus (15 cases) and S. epidermidis (11 cases). The echocardiography study resulted diagnostic in 90% of the patients, valve replacements were performed in 22% of the cases. The overall mortality rate was 10%. CONCLUSIONS: The current profile of infective endocarditis is characterized by a high incidence of parenterally drug addict patients or prosthetic valves carriers. Increase of the infections of S aureus and a decrease of Streptococcus infections, as well as a less overall mortality.     

Recognition, management and prophylaxis of endocarditis

Infective endocarditis (IE) remains a disease with high morbidity and mortality. In recent years, a higher frequency of IE has been observed in the elderly, in intravenous drug users and in patients with prosthetic valves. The diverse manifestations of this disease demand a high degree of suspicion from the practitioner, in order to make an early diagnosis. Advances in and increasing use of echocardiography (especially transoesophageal) allow us to identify valvular changes earlier and more precisely. The use of the new Duke's diagnostic criteria, based on clinical manifestations and microbiological and echocardiographic findings, facilitates the diagnosis and categorisation of IE. An increase in staphylococci and other problem pathogens, such as penicillin-resistant streptococci, enterococci resistant to beta-lactams, aminoglycosides and methicillin-resistant staphylococci has been observed. Important changes have also taken place in the management of IE. There is a clear trend towards the use of shorter treatment courses, oral and once-daily regimens and outpatient programmes, all of which aim to reduce costs and provide patients with improved quality of life. Antibiotic prophylaxis for the prevention of IE is still controversial. In the past few years more rational regimens have been used, and indications are now more precise. In spite of all this, however, few cases are prevented and patient compliance to the prophylaxis regimens remains low.     

Intramuscular clindamycin for therapy of infective endocarditis. Report of 23 cases and review of the literature

Twenty-three patients with infective endocarditis received intramuscular clindamycin (Cleocin) for treatment. Thirteen had acute Staphylococcus (S.) aureus endocarditis but none had involvement of the aortic valve. Eleven of these 13 infections were heroin-related and involved the tricuspid valve.Twenty-one patients were successfully treated. Two patients with heroin-related S. aureus infection failed to respond to intramuscularly administered clindamycin, but responded to retreatment with methicillin. There have been 34 reported cases of endocarditis treated with clindamycin. Although 80 percent of all cases due to staphylococci responded favorably, almost all were heroin-related tricuspid valve infections. In addition 91 percent of cases due to aerobic streptococci responded but, surpisingly, treatment failed in three of four cases of anaerobic endocarditis. Although clindamycin can be useful in streptococcal endocarditis and in some cases of heroin-related S. aureus tricuspid endocarditis, caution should be exercised in its use. It is "less" bactericidal than the penicillins or cephalosporins, and organisms have become resistant during treatment. Furthermore, patients with anaerobic endocarditis have not responded well, and data are not available to recommend administration of clindamycin for acute S. aureus infections engrafted on the aortic or mitral valve.     

N-acetylcysteine prevents development of the hyperdynamic circulation in the portal hypertensive rat

Infective endocarditis, defined as pathologically or clinically definite by the Duke criteria, was observed in 14 transplant recipients at our institutions. In addition, we reviewed 32 previously reported cases in solid organ transplant recipients. The spectrum of organisms causing infective endocarditis was clearly different in transplant recipients than in the general population; 50% of the infections were due to Aspergillus fumigatus or Staphylococcus aureus, but only 4% were due to viridans streptococci. Fungal infections predominated early (accounting for six of 10 cases of endocarditis within 30 days of transplantation), while bacterial infections caused most cases (80%) after this time. In 80% (37) of the 46 cases in transplant recipients, there was no underlying valvular disease. Seventy-four percent (34) of the 46 cases were associated with previous hospital-acquired infection, notably venous access device and wound infections. Three patients with S. aureus endocarditis had had an episode of S. aureus bacteremia > 3 weeks prior to the diagnosis of endocarditis and had received treatment for the initial bacteremia of < 14 days' duration. The overall mortality rate was 57% (26 of 46 patients died), with 58% (15) of the 26 fatal cases not being suspected during life. Endocarditis is an underappreciated sequela of hospital-acquired infection in transplant recipients.     

Accuracy of methods using somatic cell count and N-acetyl-beta-D-glucosaminidase activity in milk to assess the bacteriological cure of bovine clinical mastitis

This study examined the capability of milk somatic cell count (SCC) and NAGase activity to discriminate between quarters that had been cured versus those that had not been cured at 4 wk after antimicrobial therapy for clinical mastitis. The distribution of microorganisms that were isolated before therapy from 630 quarters with mastitis was as follows: 225 strains of Staphylococcus aureus, 96 strains of coagulase-negative staphylococci, 152 strains of streptococci (Streptococcus dysgalactiae and Streptococcus uberis), and 157 strains of coliform bacteria. Bacteriological cure rates were 35% for mastitis caused by Staph. aureus, 75% for mastitis caused by coagulase-negative staphylococci, 66% for mastitis caused by streptococci, and 72% for mastitis caused by coliforms. Diagnostic accuracy of milk SCC and NAGase and their interquarter ratios for predicting bacteriological status of the control samples was assessed by calculating sensitivity, specificity, and accuracy and by means of receiver operating characteristic analysis. The efficiency of milk SCC and NAGase for predicting bacteriological cure was greatest for cows that had been infected with Staph. aureus. The main problem in detecting coagulase-negative staphylococci was low sensitivity, and the main problem in detecting streptococci and coliforms was low specificity. Receiver operating characteristic analysis is not completely suitable for the detection of mastitis because reference method bacteriology and indirect tests can never fully agree. To assess the recovery of cows from mastitis caused by Staph. aureus, bacteriology should be supplemented with an examination of milk SCC or NAGase activity at threshold values such as those presented here.     

2 mechanisms of tetracycline resistance in bacteria

Two mechanisms of resistance to chlortetracycline stipulated by retarded transport of the antibiotic or decreased sensitivity to it of the translation apparatus were studied using clinical bacterial strains and strains obtained under laboratory conditions. No strict proportion between the population resistance to the antibiotic and the level of a decrease in its absorption by the bacterial cells was observed in most of the clinical and laboratory strains of Staph. aureus. Apparently the resistance level observed in the bacteria cannot be entirely explained by the retarded transport of the antibiotic in these cases. Direct experiments showed that sensitivity to chlortetracycline in the protein-synthesizing apparatus of some resistant strains of Staph. aureus 209 was decreased 10 times. On the other hand correlation between the level of the decrease in the absorption of the antibiotic and the level of the bacteria resistance to it was observed in resistant strains of E. coli. The protein-synthesizing apparatus of the resistant strains in this case preserved its sensitivity to chlortetracycline. Sensitivity of the protein-synthesizing apparatus to the antibiotic did not change in the process of the resistance induction by incubation of the baceria in the presence of low concentrations of the antibiotic.     

Accidental acute fatal sodium nitrite poisoning

OBJECTIVES: To report two patients who developed reactive arthritis in association with Staphylococcus aureus infection. METHODS: A review of the case notes of two patients. RESULTS: Two adult female patients have developed sterile arthritis in association with Staph aureus infection. The first patient has had two episodes of arthritis; the first followed olecranon bursitis, the second followed infection of a central venous catheter used for dialysis. The second patient developed sterile arthritis while being treated for pyomyositis. Both patients had a self limited arthritis and were HLA-B27 negative. CONCLUSION: Reactive arthritis may rarely follow Staph aureus infection. HLA-B27 negativity may be associated with a self limited arthritis in these cases.     

Short-course antibiotic therapy for right-sided endocarditis caused by Staphylococcus aureus in injection drug users

Right-sided endocarditis caused by Staphylococcus aureus is a frequent complication of injection drug use. Fortunately, the prognosis for this infection when treated with the standard regimen of 4 to 6 weeks of parenteral antistaphylococcal antibiotics is favorable. Nevertheless, in many cases, once drug users feel better, they leave the hospital against medical advice before completing the full course of antibiotic therapy. This problem has stimulated interest in shortening the duration of antibiotic to a penicillinase-resistant penicillin. Data from in vitro synergy studies and animal models of endocarditis suggest that S. aureus can be eradicated more quickly by combination therapy than by monotherapy. Reports of three prospective, nonrandomized clinical trials have been published that support the use of a 2-week course of a penicillinase-resistant penicillin and an aminoglycoside antibiotic to treat uncomplicated, exclusively right-sided endocarditis caused by methicillin-susceptible S. aureus in injection drug users.