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[Antibiotic susceptibility of bacteria isolated from surgical infections (first report)].

In vitro activities of several antimicrobial agents against bacterial pathogens isolated from patients with primary and postoperative infections were investigated in 1982 and 1983. Antimicrobial agents examined were as follows: sulbenicillin (SBPC), piperacillin (PIPC), cephalothin (CET), cefazolin (CEZ), cefmetazole (CMZ), cefotiam (CTM), cefoperazone (CPZ), cefotaxime (CTX), ceftizoxime (CZX), cefmenoxime (CMX), latamoxef (LMOX), lincomycin (LCM), gentamicin (GM) and amikacin (AMK). Specimens for bacterial isolation included plus, fluid drawn by centesis, or bile. Blood samples of septicemia were excluded. The antimicrobial activities of these drugs were determined by the agar plate dilution method of the Japanese Society of Chemotherapy. There were 123 strains obtained in the 1982 survey and 252 strains in the 1983 survey. Little or no differences were seen in frequencies of isolation between the isolates of principal species in 1982 and those in 1983. Isolation frequencies of pathogens in primary infections were, in an order of decreasing frequency, E. coli (25.6%), anaerobes (21.1%), Streptococcus sp. (14.3%), Staphylococcus sp. (11.3%); in postoperative infections, Streptococcus sp. was most frequent (28.6%), followed by Pseudomonas sp. (17.6%), anaerobes (12.6%), E. coli (10.9%), Staphylococcus (10.1%). Against S. aureus, CEZ, CTM, LCM and GM had similar degree of activity with CET being somewhat more active. CMX was the most active drug among the third generation cephems tested against S. aureus. No strain was CTM, CEZ, and LCM-resistant at the same time. Over 90% of E. coli, were sensitive to CTX, CZX and CMX, inhibited by 0.10 microgram/ml, while E. coli were slightly less susceptible to CPZ and LMOX. Penicillins were not very active against K. pneumoniae, and only 60% of K. pneumoniae were inhibited by PIPC at concentrations of 12.5 micrograms/ml. Third generation cephems, CTX, CMX and CZX, proved highly active against K. pneumoniae; over 90% of K. pneumoniae was inhibited by CTX, CMX and CZX at a concentration of 0.10 microgram/ml. About 60% of P. aeruginosa was inhibited by 3.13 micrograms/ml of PIPC and GM but was resistant to SBPC. This survey should be very useful for the selection of an appropriate drug for prophylaxis if the frequencies of incidences of pathogens in postoperative infections are taken into account in selecting the most active antibiotic agent(s) against the most frequent genus, genera and species of pathogens.

Cephalosporins↗

Recurrent acute otitis media occurring within one month from completion of antibiotic therapy: relationship to the original pathogen.

OBJECTIVES: (1) To determine the relationship between acute otitis media (AOM) pathogens isolated in cases of early clinical recurrence of AOM (occurring within 1 month from completion of therapy) to the original pathogens causing the initial AOM episode; and (2) To determine whether shorter time intervals between completion of antibiotic therapy and clinical recurrences of AOM are associated with higher rates of true bacteriologic relapse. PATIENTS AND METHODS: From 1995 through 2000, 1077 infants and young children ages 3 to 36 months with AOM were enrolled in double tympanocentesis (performed on Day 1 in all patients and Days 4 to 6 in those initially culture-positive) studies. Of these, 834 (77%) completed successfully the antibiotic treatment [pathogen eradication on Days 4 to 6 of therapy or no pathogen on middle ear fluid (MEF) culture on Day 1 and clinical improvement at end of therapy]. Patients were followed for 3 to 4 weeks after completion of therapy, and additional MEF cultures were obtained if clinical recurrence occurred. True bacteriologic relapse was defined as the presence of a pathogen identical with that isolated before therapy by serotype and pulsed field gel electrophoresis for and by pulsed field gel electrophoresis for Streptococcus pneumoniae and beta-lactamase production for Haemophilus influenzae. RESULTS: MEF cultures were performed in 108 consecutive patients with early recurrent AOM. One hundred pathogens were isolated at recurrence in 88 of 108 (81%) patients: 54 H. influenzae; 45 S. pneumoniae; and 1 Moraxella catarrhalis. Most recurrent AOM episodes developed during the first 2 weeks of follow-up; 39 (36%), 38 (35%), 21 (19%) and 10 (9%) recurrent AOM episodes occurred on Days 1 to 7, 8 to 14, 15 to 21 and 22 to 28 after completion of therapy, respectively. In most patients these episodes were caused by a new pathogen. True bacteriologic relapses were found in 30 (28%) of 108 patients whose MEF cultures were positive for 35 pathogens: 13 of 108 (12%) S. pneumoniae; 12 of 108 (11%) H. influenzae; and 5 of 108 (5%) both. When timing of recurrent AOM after completion of therapy was analyzed, true bacteriologic relapses were found in 16 of 39 (41%), 10 of 38 (26%), 3 of 21 (14%) and 1 of 10 (10%) of all episodes on Days 1 to 7, 8 to 14, 15 to 21 and 22 to 28 after completion of therapy, respectively (P = 0.01). The respective rates for were 11 of 17 (65%), 3 of 10 (30%), 3 of 13 (23%) and 1 of 5 (20%) (P = 0.02). For H. influenzae the respective rates were 8 of 19 (42%), 9 of 23 (39%), 0 of 8 (0%) and 0 of 4 (0%) (P = 0.02). CONCLUSIONS: Most recurrent AOM episodes occurring within 1 month from completion of antibiotic therapy are in fact new infections. Most of the true bacteriologic AOM relapses occur within 14 days after completion of therapy, but even during this time interval most of the recurrences are caused by new pathogens. H. influenzae is very unlikely to cause true bacteriologic AOM relapses 14 days or later after completion of therapy.

Acute Disease↗

beta-Hemolytic streptococci and other beta-hemolytic organisms in apical periodontitis and severe marginal periodontitis.

Thirteen teeth with necrotic pulps and apical periodontitis and nine severe periodontal pockets were cultured for presence of beta-hemolytic streptococci and other beta-hemolytic organisms. Samples were dispersed and plated on two non-selective and one selective growth media and incubated anaerobically and in 10% CO2 in air. A total of 59 beta-hemolytic colonies were purified and identified. Eight beta-hemolytic streptococcal isolates were obtained from three of the severe marginal periodontitis sites. All were identified as belonging to the Streptococcus sanguis group. No beta-hemolytic streptococci were detected in apical periodontitis samples. Twenty obligately anaerobic isolates were detected, all of which were known periodontal and endodontic pathogens. Isolates from apical periodontitis sites were identified as Propionibacterium acnes, Actinomyces naeslundii, Actionomyces odontolyticus and Peptostreptococcus micros, while severe marginal periodontal sites contained the same species with the addition of Actinomyces viscosus and Actinomyces meyeri. Of 19 staphylococci and micrococci, Staphylococcus epidermidis was the predominant isolate in both apical periodontitis and severe marginal periodontitis sites. However, less commonly known organisms such as Staphylococcus cohnii and Micrococcus sp. were identified in severe marginal periodontitis sites. The isolation of Bacillus sp. (12 isolates) in one severe marginal periodontitis and two apical periodontitis subjects was especially interesting, warranting consideration of this organism as a legitimate isolate and potential pathogen in oral disease.

Bacillus↗

Relative frequency of nosocomial pathogens at a university hospital during the decade 1980 to 1989.

BACKGROUND: We compared the relative frequency of pathogens isolated from 1985 to 1989 (N = 4358) with those isolated from 1980 to 1984 (N = 5290) in a university hospital to determine trends in the relative importance of pathogens causing nosocomial infection. METHODS: Our study was based on surveillance data prospectively obtained between 1980 and 1989 from a 600-bed university hospital. Statistically significant trends occurring from 1980 to 1984 to 1985 to 1989 were determined by chi 2 tests with Bonferroni corrections (i.e., p less than [0.05/17]). RESULTS: Overall an increased frequency of isolation occurred for Candida and other yeasts and for Haemophilus species. A decreased frequency was noted for Proteus species, non-Bacteroides anaerobes, and Serratia species. Comparison of 1985 to 1989 with 1980 to 1984 revealed that the most significant change in nosocomial pathogens was the marked increase in infections with yeast, principally Candida species. Candida and other yeast infections increased 40%, from 7.6% (rank, 5) to 10.6% (rank, 3) of all pathogens isolated. Increases, which occurred in urine, blood, and wound isolates, were especially marked among surgical patients. In addition, a significant increase was noted among blood isolates in the isolation of yeast other than Candida albicans. CONCLUSIONS: We conclude that Candida and other yeasts are being isolated increasingly as causative agents of nosocomial infection.

Cross Infection↗

Observations on the infectivity and pathogenicity of three isolates of Ostertagia spp sensu lato in calves.

After experimental infection of three groups of calves with three different defined isolates of Ostertagia spp sensu lato a marked variation in the infectivity and degree of pathological change was noted. The most highly infective and pathogenic isolate contained approximately 30 per cent O leptospicularis in addition to O ostertagi (70 per cent) and a negligible number of Skrjabinagia lyrata. The other two isolates consisted solely of O ostertagi (approximately 90 per cent) and S lyrata (approximately 10 per cent) and showed comparable infectivity and pathogenicity to that commonly recorded. The greater pathogenicity of the isolate containing O leptospicularis was attributed to the higher infectivity and the greater damage caused to the gastric mucosa by individual parasites when compared with O ostertagi.

Abomasum↗

The African swine fever virus thymidine kinase gene is required for efficient replication in swine macrophages and for virulence in swine.

African swine fever virus (ASFV) replicates in the cytoplasm of infected cells and contains genes encoding a number of enzymes needed for DNA synthesis, including a thymidine kinase (TK) gene. Recombinant TK gene deletion viruses were produced by using two highly pathogenic isolates of ASFV through homologous recombination with an ASFV p72 promoter-beta-glucuronidase indicator cassette (p72GUS) flanked by ASFV sequences targeting the TK region. Attempts to isolate double-crossover TK gene deletion mutants on swine macrophages failed, suggesting a growth deficiency of TK- ASFV on macrophages. Two pathogenic ASFV isolates, ASFV Malawi and ASFV Haiti, partially adapted to Vero cells, were used successfully to construct TK deletion viruses on Vero cells. The selected viruses grew well on Vero cells, but both mutants exhibited a growth defect on swine macrophages at low multiplicities of infection (MOI), yielding 0.1 to 1.0% of wild-type levels. At high MOI, the macrophage growth defect was not apparent. The Malawi TK deletion mutant showed reduced virulence for swine, producing transient fevers, lower viremia titers, and reduced mortality. In contrast, 100% mortality was observed for swine inoculated with the TK+ revertant virus. Swine surviving TK- ASFV infection remained free of clinical signs of African swine fever following subsequent challenge with the parental pathogenic ASFV. The data indicate that the TK gene of ASFV is important for growth in swine macrophages in vitro and is a virus virulence factor in swine.

African Swine Fever↗

Bacteria, viruses, yeasts and protozoans associated with diarrheal disease in Singapore.

Labile toxin producing enterotoxic E. coli (ETEC) were the commonest pathogen isolated from diarrheal stools of hospitalized children (21%) and adults (26%) in Singapore. Salmonellas ranked a close second in children (19%). Other bacterial pathogens were isolated from less than 5% of subjects. Blastocystis hominis was detected in 4.3% of diarrheal stools when a simple sedimentation technique was used. Cryptosporidium was not detected at all. An analysis of yeast counts in smears of diarrheal and non-diarrheal stools suggested they were etiologically associated with at least 6% of diarrhea in children and 19% in adults. Testing for rotaviruses by Latex agglutination and for adenovirus by electronmicroscopy showed an association with 6 per cent and 3 per cent diarrhea respectively. The study highlighted a need for: case control studies on ETEC and B. hominis; studies on the epidemiology of diarrhea by yeasts; establishing the true incidence of adenovirus diarrhea; studies on the prevalence and seasonality of rotavirus infection in Singapore.

Adenovirus Infections, Human↗

Diarrheal illness among infants and toddlers in day care centers. II. Comparison with day care homes and households.

During the second year of a prospective study of diarrheal illness among 0- to 36-month-old children in day care centers in Maricopa County, Arizona, we concurrently studied children of the same age in 30 day care homes and 102 households not using day care. The seasonal pattern of diarrhea, frequency of pathogen isolation, and relative frequency of individual pathogens were similar in the three settings. Giardia lamblia and rotavirus were the most common enteropathogens. Asymptomatic infection was identified in 14% to 21% of infant-toddler contacts of pathogen-positive cases of diarrhea. We compared rates of diarrhea in the three settings using five serial biweekly family-based surveys during the period of highest diarrhea rates. The incidence in infants and toddlers in DCCs (42 cases per 100 child months) was significantly higher than in DCHs (23 cases per 100 child-months) and in households not using day care (27 cases per 100 child-months); the DCH rate did not differ significantly from that in households not using day care. Among household sample children who began using day care during the survey period, the incidence of diarrhea was significantly higher than in household sample children not using day care.

Age Factors↗

Clinical trial of ototopical ofloxacin for treatment of chronic suppurative otitis media.

A multicenter, open-label prospective trial was performed to determine the clinical and microbiologic efficacy of ofloxacin (OFLX) otic solution in the treatment of subjects > or =12 years with chronic suppurative otitis media (CSOM) and a chronically perforated tympanic membrane in the infected ear(s). A total of 207 patients at 27 centers in the United States and Central America received OFLX 0.5 mL instilled ototopically twice daily for 14 consecutive days. The primary clinical end point was cure (dry ear) or failure (not dry ear). The primary microbiologic end point was eradication of baseline pathogens. Because there was no comparator and there were few data in the literature regarding clinical efficacy in patients treated with other regimens, the efficacy of OFLX was compared with data recorded in the clinical records of historical-practice control (HPC) or current-practice control (CPC) subjects. The incidence of clinical cure in clinically evaluable OFLX-treated patients (91%; 148 of 162 subjects) was significantly higher than in HPC subjects (67%; 124 of 185 subjects) or CPC subjects (70%; 38 of 54 subjects). OFLX eradicated all baseline pathogens isolated in microbiologically evaluable subjects. These pathogens were predominantly Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis. The most common treatment-related adverse event, bitter taste, occurred in 17% (35 of 207) of OFLX-treated subjects. Thus OFLX 0.5 mL administered twice daily for 14 days was effective in resolving the signs and symptoms of CSOM in subjects > or =12 years, was significantly more effective than therapies used to treat HPC or CPC subjects, and was well tolerated.

Adolescent↗

Efficacy and safety of aztreonam in the treatment of patients with renal failure.

The efficacy and safety of aztreonam for treatment of gram-negative bacterial infections in patients with renal failure were evaluated in an open study. Thirty-nine patients (22-82 years old) with renal failure (chronic, 25; acute, 14) were treated for 40 severe gram-negative bacterial infections. All 41 gram-negative pathogens isolated were sensitive to aztreonam; the pathogens included Escherichia coli (12), Pseudomonas aeruginosa (8), Klebsiella species (7), Proteus species (7), Enterobacter species (5), Serratia marcescens (1), and Acinetobacter species (1). Complete cure (clinical and bacteriologic) was achieved in 31 (77.5%) of 40 infections and improvement (clinical improvement with or without bacteriologic cure) in four (10%). Bacterial eradication of 34 (82.9%) of the infecting pathogens was achieved. The only significant adverse effect noted was a slight, transient elevation in the level of serum transaminases in four patients (10%). Renal function of the patients improved with treatment. Levels of serum creatinine decreased from 3.79 +/- 2.84 to 3.30 +/- 2.52 mg/dL after treatment (P less than .002). It was concluded that aztreonam is effective and safe for the treatment of gram-negative bacterial infections in patients with renal failure.

Acinetobacter Infections↗

An assessment of temafloxacin in the treatment of chronic bacterial prostatitis.

Based on its in-vitro activity against the majority of organisms associated with bacterial prostatitis and its excellent penetration into prostatic tissue, prostatic secretions and seminal fluid, temafloxacin appears to be a suitable agent for the treatment of prostatic infections. The efficacy and safety of temafloxacin 400 mg bd for 28 days were assessed in 61 patients from ten centres in Germany with symptomatic bacterial prostatitis diagnosed by segmented localizing cultures. Urine and prostatic secretions were obtained for culture. Clinical signs and symptoms were evaluated at two weeks during treatment, and at 5 to 9 days and 26 to 30 days after treatment. Safety was monitored during and at the end of treatment. Escherichia coli and Enterococcus spp. were the most frequent pathogens. In 41 clinically and bacteriologically evaluable patients, 37 (90%) were successfully treated at 5 to 9 days; four of these patients did not return for follow-up at the final visit and the remaining patients (33) continued to be clinically cured or improved. Thirty-seven patients (90.2%) had eradication of pre-treatment pathogens at 5 to 9 days after treatment; three of these patients did not return for this final follow-up visit. There were six patients with persistent or recurrent pathogens isolated and six patients with reinfecting pathogens. Thus, 26 of 38 (68%) evaluable patients at visit 5 were free from infection (from either a pre-treatment pathogen or any subsequent new infecting pathogen) up to 26 to 30 days after treatment. One clinically evaluable but bacteriologically non-evaluable patient was classified as a therapeutic failure after nine days of treatment and was not included in the final assessment. Improvement in the severity of specific signs and symptoms was observed in greater than 90% of cases. Mild to moderate adverse events, mostly occurring during the first or second weeks of long-term therapy, were reported in 11.5% of patients. Temafloxacin 400 mg bd, for four weeks was very effective and well tolerated by the majority of patients with documented bacterial prostatitis.

Administration, Oral↗

Moxalactam treatment of anaerobic infections in cancer patients.

Of 30 patients with predominantly anaerobic localized infections superimposed on chronic tissue damage related to trauma, ischemia, or tumor, 22 (73%) responded satisfactorily to moxalactam therapy. Moxalactam-resistant anaerobic pathogens emerged in two patients and were responsible for treatment failure. In six patients, two of whom also acquired resistant anaerobic pathogens, isolation of moxalactam-resistant aerobic pathogens increased during therapy.

Adult↗

An overview of results of world-wide clinical trials with cefadroxil.

Céfadroxil, a new semisynthetic oral cephalosporin, is absorbed similarly by fasted and non-fasted subjects, produces sustained serum levels and is eliminated at a relatively slow rate. These pharmacokinetic properties permit less frequent and more convenient dosage scheduling than cephalexin and cephradine and consequently greater patient compliance. Cefadroxil was evaluated for safety in 1051 patients and for efficacy in 1030 patients. Overall it achieved a 91.8% rate of clinical success resulting from 881 complete cures and sixty-five clinical cures. Among 363 patients with respiratory tract infections and 471 patients with genito-urinary tract infections, cefadroxil treatment produced 97.5% and 84.5% clinical success, respectively. In the remaining infectious diseases treated, cefadroxil therapy resulted in 99.0% clinical success. Cefadroxil eradicated 87% of 1110 pathogens isolated, among which the most predominant pathogens were Staphylococcus aureus, beta-haemolytic streptococci, Streptococcus pneumoniae, Escherichia coli and Proteus mirabilis. Drug-related side-effects were reported in 7.2% of the patients.

Adolescent↗

Phylogenetic relationships of southern African West Nile virus isolates.

Phylogenetic relationships were examined for 29 southern African West Nile virus (formal name West Nile virus [WNV]) isolates from various sources in four countries from 1958 to 2001. In addition, sequence data were retrieved from GenBank for another 23 WNV isolates and Kunjin and Japanese encephalitis viruses. All isolates belonged to two lineages. Lineage 1 isolates were from central and North Africa, Europe, Israel, and North America; lineage 2 isolates were from central and southern Africa and Madagascar. No strict correlation existed between grouping and source of virus isolate, pathogenicity, geographic distribution, or year of isolation. Some southern African isolates have been associated with encephalitis in a human, a horse, and a dog and with fatal hepatitis in a human and death of an ostrich chick.

Aedes↗

Acquisition of Salmonella flora by turtle hatchlings on commercial turtle farms.

A commercial turtle pond in South Louisiana was studied to identify the mechanism by which turtle hatchlings acquire Salmonella flora. The visceral organs and mature eggs removed from 31 adult gravid female turtles over the course of two egg-laying seasons and from 37 adult females during one winter dormant period were examined bacteriologically for Salmonella. Pond water, egg nest soil, and hatchlings produced by eggs removed from the oviducts and nest soil were also tested. Eighty-eight turtles hatched from eggs removed from the oviducts of 15 turtles at necropsy did not excrete or harbor systemically Salmonella, nor were these pathogens isolated from ovarian tissue or immature eggs. The findings suggest transovarian transmission of these pathogens does not occur frequently. Turtles hatched from eggs retrieved from soil nests 1 to 2 h after deposition harbor and excrete these organisms. This result coupled with the isolation of these pathogens from the cloaca, colon contents, and bursal fluid from 18 females captured in the act of egg laying supports the cloaca to egg and nest soil to egg mode for salmonellae infection in the resultant hatchling. Salmonella arizonae and Salmonella serogroups B, C2, and E1 were isolated from the cloaca, colon contents, pond water, and nest soil, and were excreted by hatchlings produced from eggs removed from the soil nests. These same serogroups were isolated from the colon contents of 19 of 37 females tested during the dormant period, suggesting the salmonellae persist in the pond environment in the adult throughout the year.

Animals↗

A time-dependent analysis of intensive care unit pneumonia in trauma patients.

BACKGROUND: Appropriate and timely antibiotic therapy to treat pneumonia in trauma patients is extremely important. We evaluated the incidence and microbiology of pneumonia stratified by days postadmission and risk factors. METHODS: Prospective data were collected on 714 trauma patients admitted to the intensive care unit over a 1-year period. Pneumonia was classified as community acquired (CAP) (< or = 3 days), early nosocomial (ENP) (4-6 days), or late nosocomial (LNP) (> or = 7 days). In addition, pneumonia was classified as CAP only, nosocomial only (NI), or combination (CAP and NI, or ENP and LNP) pneumonia. Strict institutional guidelines were followed for diagnosis. RESULTS: One hundred eighty-two patients (25%) were diagnosed with 204 pneumonias over the study period. One hundred twenty-five (61%) of these pneumonias were ventilator associated. Staphylococcus aureus and Haemophilus influenzae were the most common pathogens isolated. Twenty-one percent of patients with CAP acquired an LNP (p < 0.025), in which Pseudomonas was the most common organism. Haemophilus caused LNP in 12% of patients. Cancer (p < 0.01), liver failure (p < 0.05), and age (p < 0.01) were predictive of nontypical pathogens in patients with CAP and ENP (p < 0.05). Obesity was most predictive of increased ventilator days (p < 0.001) and intensive care unit length of stay (p < 0.001). Increased age, alcohol abuse, and field airway were most predictive of mortality. CONCLUSION: Unanticipated pathogens were isolated in each class of pneumonia. The clinician must be aware of significant risk factors that may predispose patients to pathogens that are not ordinarily covered with standard antibiotic therapy.

Adult↗

Airway inflammation and etiology of acute exacerbations of chronic bronchitis.

STUDY OBJECTIVES: The etiologic role of bacterial pathogens isolated from sputum culture in 40 to 50% of acute exacerbations of chronic bronchitis (AECB) is controversial. If bacterial pathogens cause these AECB, they should be associated with greater neutrophilic airway inflammation than pathogen-negative exacerbations. DESIGN: This hypothesis was tested by comparing levels of interleukin (IL)-8, tumor necrosis factor (TNF)-alpha, and neutrophil elastase (NE) in 81 sputum samples obtained from 45 patients with AECB. Four groups were compared. In the first three groups, nontypable Haemophilus influenzae (n = 20), Haemophilus parainfluenzae (n = 27), and Moraxella catarrhalis (n = 14) were isolated as sole pathogens, respectively. In the fourth group, only normal flora was isolated (n = 20). Paired samples, obtained from individual patients at different times, that differed in their culture results were also compared. SETTING: An outpatient research clinic at a Veterans Affairs Medical Center. PATIENTS: These patients were participating in a prospective, longitudinal study of the dynamics of bacterial infection in chronic bronchitis, for which they were seen in the study clinic on a monthly basis as well as when they were experiencing symptoms suggestive of AECB. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: H influenzae exacerbations were associated with significantly higher sputum IL-8, TNF-alpha, and NE. M catarrhalis exacerbations demonstrated significantly higher sputum TNF-alpha and NE when compared to pathogen-negative exacerbations. H parainfluenzae-associated exacerbations had an inflammatory profile similar to pathogen-negative exacerbations. Sputum elastase level distinguished bacterial from nonbacterial AECB and correlated with clinical severity of the AECB. CONCLUSIONS: Increased airway inflammation associated with isolation of H influenzae and M catarrhalis supports an etiologic role of these pathogens in AECB.

Acute Disease↗

Multiple sample flow through immunomagnetic separator for concentrating pathogenic bacteria.

The standard method of immunomagnetic separation for isolating pathogenic bacteria from food and environmental matrices processes 1 ml volumes. Pathogens present at low levels (<0.5 pathogenic bacteria/g) will not be consistently detected by this method. Here a multiple sample flow through immunomagnetic separator has been designed and tested to process large volume samples (50 to 250 ml). Preliminary results show >97% recovery of polydisperse magnetic particles (diameter range 1 to 8 microm) containing 29-33% w/w Fe3O4 content. Between 70 and 130 times more of the pathogenic bacteria Escherichia coli O157 is recovered from PBS compared with the standard 1 ml method. Also, the recovery of E. coli O157 from beef mince homogenates, after a 4 h incubation at 42 degrees C, is between 80 and 180 times higher than the standard 1 ml method.

Bacteria↗