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Improving clinical outcome in bacteremia.

Bacteremia is associated with significant morbidity and mortality. There is wide variation in morbidity and mortality rates according to organism and predisposing conditions. Additionally, prompt administration of appropriate antimicrobial agents is associated with a decrease in mortality. Unfortunately, many bacteremic patients receive inappropriate or no antibiotics. Infectious disease consultation can decrease the number of patients receiving inappropriate initial therapy. 'Quality standard for the treatment of bacteremia' (Gross et al., 1994, Infection Control and Hospital Epidemiology 15, 189-192) is a consensus paper; its purpose is to 'improve the treatment of hospitalized patients with documented bacteremia by ensuring that they receive an antibiotic appropriate in light of the blood-culture susceptibility of the pathogen isolated.' A programme to assess the treatment of bacteremia can improve the quality of care with a modest commitment of additional resources. Many of the activities could be performed by a pharmacist, infection control practitioner, or pathologist. However, physician-to-physician communications are most likely to be successful. This programme should be considered a component of a hospital's quality-improvement programme; either the hospital quality assurance or infection control committee could be responsible for the programme. We encourage adoption of the standard, and recommend prospective monitoring to include the choice of empiric antimicrobial agents.

Anti-Bacterial Agents↗

Piscirickettsia salmonis: a Gram-negative intracellular bacterial pathogen of fish.

Piscirickettsia salmonis is the first Gram-negative, intracellular bacterial pathogen isolated from fish and is a significant cause of mortality in salmonid fish. Recent reports of P. salmonis or P. salmonis-like organisms from new fish hosts and geographic regions have increased the interest in the bacterium. In this review, the important characteristics of the bacterium including recent taxonomic changes, features of the disease caused by the bacterium including transmission, hosts, reservoirs, diagnostic procedures, and current approaches for prevention and treatment have been discussed. The reader is also directed to other reviews concerning the bacterium and the disease it causes (Fryer & Lannan 1994, 1996; Almendras & Fuentealba 1997; Lannan, Bartholomew & Fryer 1999; House & Fryer 2002; Mauel & Miller 2002).

Animals↗

Evaluation of the clinical efficacy of marbofloxacin (Zeniquin) tablets for the treatment of canine pyoderma: an open clinical trial.

The efficacy and field safety of marbofloxacin (Zeniquin) for the treatment of superficial and deep bacterial pyoderma were evaluated. Seventy-two dogs were treated with 2.75 mg kg-1 of marbofloxacin orally once daily for 21 or 28 days. Sixty-two dogs (86%) had superficial pyoderma and 10 (14%) had deep pyoderma. A history of prior pyoderma was reported in 39/72 dogs. Pretreatment aerobic bacteriologic cultures of skin lesions were performed in 47 cases and the predominant pathogen isolated was Staphylococcus intermedius. Treatment was successful in 62/72 (86.1%) dogs, improvement was noted in 6/72 (8.3%) dogs and treatment failed in 4/72 (5.6%) dogs. Adverse effects associated with treatment included listlessness, anorexia, vomiting, soft stool, flatulence and polydipsia; these adverse effects were seen in only 6/81 dogs. Marbofloxacin was safe and effective for the treatment of superficial and deep pyoderma in dogs at the dosage used in this study.

Administration, Oral↗

Tinea pedis in Korean children.

BACKGROUND: Tinea pedis is an infrequent disease in children before the age of puberty. There are few epidemiologic and clinical data regarding cases of tinea pedis observed in children. Materials and methods We prospectively collected all cases of tinea pedis in children diagnosed during the years 1995-1997. Only those showing a positive result with potassium hydroxide preparation were included in the study. We performed fungal cultures in Sabouraud's agar in all cases to document the etiologic fungi. The clinical characteristics were investigated. RESULTS: A total of 21 children, aged 3 months to 14 years, were included. Fifteen patients were boys and six were girls. The mean age was 7.1 years. All the children were otherwise healthy. Prior to the establishment of the diagnosis of tinea pedis, 17 patients (80.9%) were treated for eczema without improvement. The intertriginous type was most common (53.3%). The first or second toe-webs were the sites of predilection (32.3%). Eighteen children (86%) had a family history of tinea pedis and more than half of cases (52.4%) showed occurrence in the summer. The results of fungal cultures were positive in 13 patients (57%). Trichophyton rubrum was the most commonly isolated pathogen (69.2%). The other associated dermatoses were onychomycosis (33.3%), atopic dermatitis (14%), plantar warts (10%), and chronic urticaria (5%). Tinea pedis and onychomycosis cleared after treatment with topical antifungals with or without systemic antifungals in all cases. CONCLUSIONS: Tinea pedis in children can occur more frequently than suspected. Our study shows the strong association with a family history and the seasonal relationship with occurrence in summer in more than half of cases. We suggest that tinea pedis should be considered in the differential diagnosis of foot dermatitis in children.

Adolescent↗

Invasive aspergillosis in cancer.

Ten confirmed cases of invasive aspergillosis (IA) in cancer patients were analysed retrospectively. Eight were pulmonary, one was sinonasal and one was cutaneous. The majority of patients had haematological malignancies (7), the remaining three were cases of solid tumours. Fever was present in all 10 cases. Cough and lung signs were present in all eight cases of invasive pulmonary aspergillosis. Haemoptysis was encountered in three of nine cases of pulmonary and sinonasal aspergillosis. Mortality was low (2%). While corticosteroids, antibiotics and anticancer chemotherapy/radiotherapy were factors predisposing the patients to IA, neutropenia was perhaps responsible for their mortality. Seven of the patients had other associated pathogens isolated in culture in addition to Aspergillus spp. Aspergillus fumigatus was the predominant species, followed by A. flavus, A. glaucus, A. nidulans and A. niger. Direct microscopic examination (in six of seven cases) and culture (six of seven cases) correlated well with radiographic and clinical findings in cases with lung involvement. Serology for anti-Aspergillus antibodies performed by gel diffusion precipitin test was positive in one case of sinonasal aspergillosis, wherein only one precipitin band was observed. Correlation of clinical symptoms, consistent radiographic findings and microbiological work-up (the latter including a triad of direct microscopy, culture and serology) are required to arrive at a diagnosis of IA, especially where histology cannot form the mainstay of diagnosis.

Adolescent↗

Symptomatic urinary tract infection in preschool Australian children.

OBJECTIVE: To describe the demographic and clinical features, short-term outcomes, microbiology and renal tract abnormalities of a cohort of young Australian children with symptomatic urinary tract infection. METHODOLOGY: A total of 304 children < 5 years with their first documented symptomatic urinary tract infection who presented consecutively to the Emergency Department of a paediatric hospital between March 1993 and December 1994 and without a known predisposing cause were identified and details of their acute illness were recorded. Renal tract sonography, micturating cystourethrography and Tc-99 m dimercaptosuccinic acid scintigraphy (DMSA) were routinely performed. RESULTS: Of those who presented with urinary tract infection, 169 were boys and 135 girls; 64% were less than 1 year of age. For children from the local community, the cumulative incidence of urinary tract infection within the first 5 years of life was estimated to be 1.9% for boys and 1.8% for girls. There were no significant differences in illness characteristics according to mode of referral or geographical locality. Presenting symptoms were generally nonspecific and not referrable to the urinary tract. There were no deaths. One per cent of children required ventilatory support, and bacteraemia occurred in 6%, all of whom were under 6 months of age. E. coli was the causal organism in 84%, and a high in vitro resistance to ampicillin/ amoxycillin (54%) was demonstrated by the pathogens isolated. Bacteriuria was eradicated in 99% with antimicrobial treatment. In this setting, the sensitivities of dipstick urinalysis (leucocyte esterase+/-nitrites) and pyuria on microscopy (>10 x 10(6) white cells L(-1)) were 85%. Abnormal DMSA scintigraphy was detected in 39%, vesicoureteric reflux in 28%, and obstructive uropathy in 1%. CONCLUSIONS: This study provides current and local data on a large sample of children <5 years with urinary tract infection, which are useful to clinicians who manage children at risk of the condition.

Acute Disease↗

Candida colonization in patients with esophageal disease: a prospective clinical study.

The incidence of Candida infection has significantly increased over the recent years, becoming the fourth most common pathogens isolated in patients admitted to intensive care units (ICU). Mortality rates ranging between 6 and 38% have been reported to be associated with candidemia. Esophageal surgery may increase the risk of systemic Candida infection in critical patients requiring postoperative ICU admission. The aim of the present study was to assess the prevalence of Candida colonization in patients with esophageal disease undergoing surgery. Between April 1999 and April 2001, 131 patients with esophageal disease and 40 healthy volunteers were prospectively tested for Candida colonization by oral and pharyngeal swab. Candida colonization was significantly more frequent in patients with esophageal disease than in control subjects (38.9 vs 7.5%, P < 0.01); the prevalence was higher in individuals with carcinoma than in those with benign disease (51.8 vs 24%, P < 0.02), and in patients undergoing neoadjuvant chemoradiation therapy compared to those having primary surgery (55.5 vs 34.4%, P < 0.01). These data suggest that Candida colonization of the gastrointestinal tract is common in patients with esophageal disease. Pharmacological attempts to prevent or reduce the magnitude of this event may be worthwhile before surgery. However, the hypothesis that antifungal oral prophylaxis with nonabsorbable drugs may lower the incidence of candidemia in patients with gastrointestinal Candida colonization, especially in those candidates to postoperative ICU admission, should be tested by randomized double-blinded studies.

Adenocarcinoma↗

Catheter-associated urinary tract infections: prevalence of uropathogens and pattern of antimicrobial resistance in a UK hospital (1996-2001).

OBJECTIVE: To assess the change in the bacterial profile and pattern of antibiotic resistance of catheter-associated urinary tract infections (CAUTIs, the most prevalent form of nosocomial infections) between 1996 and 2001. MATERIALS AND METHODS: Catheter samples of urine (CSUs) submitted in 1996, 1998 and 2001 (2451, 2460 and 3349 specimens, respectively) were analysed. The distribution of different uropathogens in bacterial CAUTIs and their in vitro antimicrobial resistance was evaluated over the study interval. The likelihood ratio test was used to assess whether there was a linear trend according to calendar year. RESULTS: Escherichia coli was the most frequently isolated pathogen in all years, but its frequency declined over time (35.6%, 32.5% and 26.6%, respectively). Enterococcus was the second most frequent overall, with a significant increase in frequency with time (11.8%, 15.3% and 22.0%, respectively). There was also a considerable change in resistance patterns to antibiotics. As a result, in 1996, CAUTIs were least often resistant to ciprofloxacin (8.0%) followed by co-amoxiclav (18.5%) and cephalexin (25.4%). In 2001, CAUTIs were least often resistant to co-amoxiclav (22.5%), followed by ciprofloxacin (27.2%) and nitrofurantoin (28.8%). CONCLUSION: The types of organisms associated with CAUTI have changed over the last 5 years in a UK institution, as have the patterns of antibiotic resistance. Currently, the most appropriate agents for the empirical management of CAUTIs seem to be co-amoxiclav, ciprofloxacin and nitrofurantoin.

Anti-Bacterial Agents↗

Infecton: a 99mTc-ciprofloxacin radiopharmaceutical for the detection of bone infection.

OBJECTIVE: To evaluate Infecton scintigraphy, with technetium-99m-radiolabeled ciprofloxacin, as a means to detect bone infection, in comparison with other conventional scintigraphic and radiologic methods. METHODS: Forty-five patients with known or suspected bone infection underwent 50 scans with Infecton. Almost all were also subjected to a three-phase 99mTc-methylene diphosphonate bone scan and most of them to a 99mTc-human polyclonal immunoglobulin scan as well as to a gallium-67-citrate scan, plus computerized tomography or magnetic resonance imaging or both. Clinical laboratory criteria for the presence of osteomyelitis were based on the definitions of the Centers for Disease Control and Prevention. RESULTS: Staphylococcus aureus and Pseudomonas aeruginosa were the most frequently isolated pathogens. Based on the CDC clinical laboratory criteria as well as on conventional scan results, Infecton was characterized in 35 studies as 'true positive', in eight as 'true negative', in two as 'false positive', in one as 'false negative', and in four as 'indeterminate'. The sensitivity and specificity of Infecton scintigraphy were found to be 97.2% and 80%, respectively, with positive and negative predictive values of 94.6% and 88.9%. CONCLUSIONS: It is concluded that Infecton is a very sensitive and quite specific marker of bone infection, but care must be taken in cases of excessive new bone formation and primary bone tumors, where false-positive results may be obtained.

Adolescent↗

Clinical studies in persistent diarrhea: dietary management with green banana or pectin in Bangladeshi children.

BACKGROUND & AIMS: Because of the beneficial intestinal effects of dietary fibers, we have evaluated the therapeutic effects of green banana or pectin in children with persistent diarrhea. METHODS: In a double-blind trial, 62 boys, age 5-12 months, were randomly given a rice-based diet containing either 250 g/L of cooked green banana (n = 22) or 4 g/kg pectin (n = 19) or the rice-diet alone (control, n = 21), providing 54 kcal/dL daily for 7 days. Stool weight and consistency, frequency of vomiting and purging, and duration of illness were measured. RESULTS: Most children (60%) had no pathogens isolated from stools, 17% had rotavirus, 5% Vibrio cholerae, 4% Salmonella group B, and 11% had enterotoxigenic Escherichia coli infections. By day 3 posttreatment, significantly (P < 0.001) more children recovered from diarrhea receiving pectin or banana than controls (59%, 55%, and 15%, respectively). By day 4, these proportions correspondingly increased to 82%, 78%, and 23%, respectively, the study diet groups being significantly (P < 0.001) different than controls. Green banana and pectin significantly (P < 0.05) reduced amounts of stool, oral rehydration solution, intravenous fluid, and numbers of vomiting, and diarrheal duration. CONCLUSIONS: Green banana and pectin are useful in the dietary management of persistent diarrhea in hospitalized children and may also be useful to treat children at home.

Antidiarrheals↗

Central venous catheter-related blood stream infections: incidence, risk factors, outcome, and associated pathogens.

OBJECTIVE: To determine the incidence, risk factors, outcome, and pathogens of central venous catheter-related bloodstream infections (CVC-BSIs). DESIGN: Prospective study. SETTING: Escorts Heart Institute and Research Centre, New Delhi, India. PARTICIPANTS: One thousand three hundred fourteen consecutive patients undergoing cardiac operations who were admitted to the intensive care unit with CVC. INTERVENTIONS: All patients were assigned into CVC-BSI (n = 35) and non-CVC-BSI (n = 1,279) groups. MEASUREMENT AND MAIN RESULTS: Of the 1,314 patients in the study, 35 (2.6%) had CVC-BSI. On univariate analysis, significant risk factors were use of multilumen catheters, coexistent infections, intra-aortic balloon counterpulsation (IABC), total ventilation hours, emergency surgery, acute physiology, age, chronic health evaluation score (APACHE II), and steroids. On multivariate analysis, duration of catheterization (24.5 +/- 10.9 v 6.1 +/- 3.2; p < 0.001), coexistent infections (57.11% v 2.61%; p < 0.001), IABC (77.1% v 4.1%; p = 0.005), and temperature (38.2 +/- 0.6 v 37.4 +/- 0.3; p < 0.001) were independent predictors of CVC-BSI. Pathogens isolated were Escherichia coli (47%), Acinetobacter species (11.7%), Enterobacter species (5.8%), Proteus species (5.8%), methicillin-resistant Staphylococcus species (11.7%), coagulase-negative Staphylococcus species (5.8%), and Candida (11.7%). The mortality rate in CVC-BSI was 22.9% as compared with 0.2% in non-CVC-BSI cases (p < 0.001). CONCLUSION: By univariate analysis, the risk factors for CVC-BSI were use of multilumen catheters, duration of catheterization, total ventilation hours, IABC, emergency surgery, APACHE II score, coexistent infections, and steroids. On multivariate analysis, duration of catheterization, IABC, coexistent infections, and temperature were independent predictors of CVC-BSI. The mortality was increased with CVC-BSI.

Bacteremia↗

A comparison of the safety and efficacy of moxifloxacin (BAY 12-8039) and cefuroxime axetil in the treatment of acute bacterial sinusitis in adults. The Sinusitis Study Group.

The aim of this multicentre, randomized study was to compare the efficacy and safety of moxifloxacin (BAY 12-8039), a new 8-methoxy fluoroquinolone, with that of cefuroxime axetil for the treatment of acute bacterial sinusitis in adults. Diagnosis was made on a range of clinical signs and symptoms combined with radiology and microbiology. A 400 mg dose of moxifloxacin was administered once daily for 7 days to 242 patients and 250 mg twice daily of cefuroxime axetil was administered to 251 patients for 10 days. The clinical success rate at the end of treatment in the evaluable population was significantly higher (96.7%) in the moxifloxacin group (204/211) than in the cefuroxime axetil group (204/225, 90.7%; 95% confidence intervals 1.5%; 10.6%). At follow-up the success rate in the moxifloxacin group was 90.7% and that for the cefuroxime axetil group was 89.2% (95% confidence intervals -4.3%; 5.4%). The predominant pathogens isolated were Streptococcus pneumoniae and Haemophilus influenzae, followed by Moraxella catarrhalis and Staphylococcus aureus. The bacteriological eradication rates were higher for moxifloxacin (94.5%, 103/109) than for cefuroxime axetil (83.5%, 96/115; 95% CI 3.6%; 19.7%). Only one S. pneumoniae infection persisted following moxifloxacin therapy in contrast with three in individuals on cefuroxime axetil. There were slightly more adverse events in the moxifloxacin group than in the cefuroxime axetil group, but there were fewer serious adverse events following moxifloxacin treatment (three vs. eight). The drug was discontinued because of adverse events in 14 moxifloxacin patients and in 11 cefuroxime axetil patients. Overall, in all assessments, moxifloxacin was at least as effective clinically and bacteriologically, and as well tolerated, as cefuroxime axetil in the treatment of acute sinusitis.

Acute Disease↗

The efficacy and safety of two oral moxifloxacin regimens compared to oral clarithromycin in the treatment of community-acquired pneumonia.

An international multi-centre, randomized, prospective, double-blind study compared oral moxifloxacin (200 mg or 400 mg once daily for 10 days) with oral clarithromycin (500 mg, twice daily for 10 days) in the treatment of community-acquired pneumonia (CAP). The clinical success rate in the evaluable population at the primary efficacy assessment, 3-5 days after the end of study treatment, was 93.9% in patients treated with 200 mg moxifloxacin; 94.4%, with 400 mg moxifloxacin; and 94.3%, with clarithromycin. Clinical success rates were maintained at follow-up, 21-28 days after the end of treatment: 90.7% (200 mg moxifloxacin), 92.8% (400 mg moxifloxacin) and 92.2% (clarithromycin). The 95% confidence intervals indicated that all three treatment regimens were equally effective in treating CAP. At follow-up, the 400 mg moxifloxacin dose had a slightly higher observed cure rate than the 200 mg moxifloxacin dose, but this was not statistically significant. The most frequently isolated pathogens were Streptococcus pneumoniae (42%), Haemophilus influenzae (19%), Haemophilus parainfluenzae (10%), Moraxella catarrhalis (6%), Klebsiella pneumoniae (5%) and Staphylococcus aureus (4%). The bacteriological success rate (eradication and presumed eradication) was 72.5% (29/40) for 200 mg moxifloxacin, 78.7% (37/47) for 400 mg moxifloxacin and 70.7% (29/41) for clarithromycin. The adverse event profile was comparable between the three treatment groups. Most adverse events, possibly or probably related to the study drug, were generally mild or moderate in severity and mostly related to the digestive system: diarrhoea, nausea and abdominal pain in 200 mg moxifloxacin patients; diarrhoea, liver function abnormalities and nausea in 400 mg moxifloxacin patients and liver function abnormalities, diarrhoea, nausea and taste perversion in clarithromycin patients. Study drugs were discontinued because of adverse events in 7/229 (3%) patients treated with 200 mg moxifloxacin, 11/224 (5%) with moxifloxacin 400 mg and 11/222 (5%) with clarithromycin. In all assessments, moxifloxacin was at least as effective clinically, and as well tolerated as clarithromycin in the treatment of CAP. Bacteriological success rates in moxifloxacin-treated patients were greater than those of clarithromycin. Moxifloxacin, given once daily, is free of many drug-drug interactions and requires no dosage adjustments in most renal hepatic deficient patients.

Administration, Oral↗

[Surgical therapy of unspecific and specific Spondylodiscitis].

AIM: The aim of this study was to evaluate the clinical and radiological results of surgical treatment of thoracic and lumbar vertebral osteomyelitis by means of one-stage extrafocal posterior stabilisation, anterior debridement, and anterior column reconstruction. METHOD: A retrospective analysis of the peri- and postoperative parameters of 62 patients with a clinical and radiographic follow-up of 2.6 years that were available for 46 patients was performed. In 42 cases, the anterior column was restored with structural bone grafts, in 20 patients, expandable titanium cages filled with morsellised autologous bone and antibiotic collagen sponges were used. To assess the course of spinal alignment a radiometric analysis was undertaken. Furthermore, the Roland-Morris score (RMS) was applied to evaluate the back pain-related disability. RESULTS: The diagnosis was made no earlier than 2.7 months after the first symptoms. Preoperatively, 40 % of the patients presented with neurological impairment, of these 76 % improved after surgery. Staphylococcus aureus was the most common pathogen isolated (32 %), Mycobacterium tuberculosis was found in 11 % of the patients. Except for one patient with revision for persistent infection and consecutive failure of the bone graft, primary eradication of the infection was achieved in all cases. At follow-up, bony fusion was radiographically observed in all patients. When using cages, the segmental loss of correction was significantly lower than when using bone grafts (1.0 vs. 4.1 degrees ). At follow-up the RMS averaged 6.6. CONCLUSION: One-stage extrafocal posterior stabilisation combined with anterior debridement and anterior column reconstruction with bone grafts or titanium cages is a safe and effective strategy for patients with vertebral osteomyelitis in need of surgery. Titanium cages have proven to be biomechanically advantageous, especially in cases of extensive destruction and are not associated with higher rates of persistence or recurrence of infection compared to autologous bone grafts.

Adult↗

Prophylactic doxycycline for travelers' diarrhea. Results of a prospective double-blind study of Peace Corps volunteers in Kenya.

We performed a randomized double-blind study to determine the efficacy of doxycycline (100 mg daily) in preventing travelers' diarrhea among 39 Peace Corps volunteers during their first five weeks in Kenya. The volunteers took either doxycycline or placebo for three weeks and were observed for an additional two weeks. Nine of 21 taking placebo and one of 18 taking doxycycline had travelers' diarrhea during the treatment period (P = 0.012). The protection seemed to persist for at least one week after the drug was stopped. Enterotoxigenic Escherichia coli was the only pathogen isolated from the placebo group, but was not detected in persons taking doxycycline. None of these organisms were resistant to doxycycline or tetracycline, whereas resistance to tetracyclines and other antibiotics was common among the nonenterotoxigenic Esch. coli. We conclude that doxycycline effectively prevented most episodes of travelers' dirrhea.

Adult↗

Limited clinical utility of blood and urine cultures in the treatment of acute pyelonephritis during pregnancy.

OBJECTIVE: The purpose of this study was to determine the utility of urine and blood cultures in the clinical management of pregnant women with acute pyelonephritis. STUDY DESIGN: Data were pooled from three randomized controlled trials that were conducted at two university-based tertiary care centers and included 391 pregnant women with pyelonephritis. The results of urine and blood cultures were correlated with clinical management decisions, outcome, length of hospital stay, and cost. RESULTS: Results of 98% of urine cultures (382/391) and 99% of blood cultures (388/391) were available for analysis. The most common pathogen isolated was Escherichia coli, which was found in 79% of the urine cultures (300/382) and in 77% of the blood cultures (27/35). Susceptibility testing revealed 46% resistance to ampicillin; 7%, 2%, and 0% resistances to first-, second-, and third-generation cephalosporins, respectively; and 1% resistance to gentamicin. Six percent of the participants (25/391) required changes in antibiotic therapy, most commonly for persistent fever (6/25, 25%). Positive blood culture results directly influenced management by prolonging the duration of hospitalization, with means of 4.6 +/- 2.6 hospital days for women with bacteremia and 2.6 +/- 1.5 hospital days for women without bacteremia (P <.001) despite similar durations of symptoms. CONCLUSION: Urine and blood cultures with sensitivity testing had limited utility in the clinical management of pregnant women with pyelonephritis. Decisions to change antibiotic treatment were affected more by clinical course than by culture results. We suggest that elimination of blood and urine cultures might simplify management and result in significant cost savings without compromising patient care.

Acute Disease↗

Recombination within natural populations of pathogenic bacteria: short-term empirical estimates and long-term phylogenetic consequences.

The identification of clones within bacterial populations is often taken as evidence for a low rate of recombination, but the validity of this inference is rarely examined. We have used statistical tests of congruence between gene trees to examine the extent and significance of recombination in six bacterial pathogens. For Neisseria meningitidis, Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus, the congruence between the maximum likelihood trees reconstructed using seven house-keeping genes was in most cases no better than that between each tree and trees of random topology. The lack of congruence between gene trees in these four species, which include both naturally transformable and nontransformable species, is in three cases supported by high ratios of recombination to point mutation during clonal diversification (estimates of this parameter were not possible for Strep. pyogenes). In contrast, gene trees constructed for Hemophilus influenzae and pathogenic isolates of Escherichia coli showed a higher degree of congruence, suggesting lower rates of recombination. The impact of recombination therefore varies between bacterial species but in many species is sufficient to obliterate the phylogenetic signal in gene trees.

Alleles↗

A highly specific one-step PCR - assay for the rapid discrimination of enteropathogenic Yersinia enterocolitica from pathogenic Yersinia pseudotuberculosis and Yersinia pestis.

Based on differences within the yopT-coding region of Yersinia. enterocolitica, Y pseudotuberculosis and Y pestis, a rapid and sensitive one-step polymerase chain reaction assay with high specificity for pathogenic Y enterocolitica was developed. By this method pathogenic isolates of Y enterocolitica can be easily identified and discriminated from other members of this genus. The entire coding sequence of the yopT effector gene of Y. pseudotuberculosis Y36 was determined.

Animals↗