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Biomedical subjects

I Brook

Publications and source records attributed to I Brook.

At least 235 records · Page 13Linked to original sources
PubMed1990

Bacteria from solid tumours.

Bacteria were grown from 63 (69%) of 91 specimens from necrotic tumours in 63 patients. Of the tumours, 14 were abdominal, 5 pelvic, 23 of the head and neck, 4 of the lungs, 4 mediastinal, 2 lymphatic, 3 of the breast, and 8 were miscellaneous. Aerobic or facultatively anaerobic bacteria only were present in 12 (19%) specimens, anaerobes only in 10 (16%), and mixed aerobic and anaerobic bacteria in 41 (65%). A total of 83 anaerobic and 47 aerobic and facultatively anaerobic bacteria were isolated. The predominant anaerobic bacteria were Bacteroides spp. (36 isolates), and anaerobic cocci (21) and Propionibacterium acnes (22). The aerobic and facultatively anaerobic bacteria most frequently isolated were Staphylococcus aureus, alpha-haemolytic streptococci, Escherichia coli (seven isolates each), S. epidermidis, Klebsiella pneumoniae and Pseudomonas aeruginosa (five isolates each). These data demonstrate that infection of tumours is usually polymicrobial.

Bacteria↗
PubMed1990

Growth of Bacteroides fragilis group in agar and broth media.

The rate of bacterial growth of four Bacteroides fragilis group organisms was determined in agar and broth media. Exponential bacterial growth occurred in agar media within 4 to 8 h, while such growth was delayed in broth media and occurred within 12-24 h after inoculation. This phenomenon may explain why antimicrobials which manifest an 'inoculum effect' may show increased resistance to antimicrobials when tested in agar media.

Bacteroides↗
PubMed1990

Oral ofloxacin therapy of Pseudomonas aeruginosa sepsis in mice after irradiation.

Death subsequent to whole-body irradiation is associated with gram-negative bacterial sepsis. The effect of oral therapy with the new quinolone ofloxacin for orally acquired Pseudomonas aeruginosa infection was tested in B6D2F1 mice exposed to 7.0 Gy of bilateral radiation from 60Co. A dose of 10(7) organisms was given orally 2 days after irradiation, and therapy was started 1 day later. Only 4 of 20 untreated mice (20%) survived for at least 30 days compared with 19 of 20 mice (95%) treated with ofloxacin (P less than 0.005). P. aeruginosa was isolated from the livers of 21 to 28 untreated mice (75%), compared with only 2 of 30 treated mice (P less than 0.005). Ofloxacin reduced colonization of the ileum by P. aeruginosa; 24 of 28 untreated mice (86%) harbored the organisms, compared with only 5 of 30 (17%) with ofloxacin (P less than 0.005). This experiment was replicated twice, and similar results were obtained. These data illustrate the efficacy of the quinolone ofloxacin for oral therapy of orally acquired P. aeruginosa infection in irradiated hosts.

Animals↗
PubMed1990

Microbiology of "normal" tonsils.

Core tonsillar cultures for aerobic and anaerobic bacteria were performed on four normal tonsils removed from four children because of velopharyngeal insufficiency and on four tonsils removed from four children because of recurrent tonsillitis. The data illustrate the presence of polymicrobial flora in the cores of normal noninflamed tonsils and the increase in their number and encapsulation during the inflammatory process.

Bacteria, Aerobic↗
PubMed1990

Microbiology of empyema in children and adolescents.

The microbiology of empyema was studied in 72 children and adolescents whose specimens yielded bacterial growth after inoculation for aerobic and anaerobic bacteria. A total of 93 organisms, 60 aerobic or facultative and 33 anaerobic, were isolated. Aerobic bacteria was isolated in 48 (67%) patients, anaerobic bacteria in 17 (24%), and mixed aerobic and anaerobic bacteria in 7 (10%). The predominant aerobic or facultative bacteria were Haemophilus influenzae (15 isolates), Streptococcus pneumoniae (13), and Staphylococcus aureus (10). The predominant anaerobes were Bacteroides sp (15 isolates, including 7 Bacteroides fragilis group and 5 Bacteroides melaninogenicus group), anaerobic cocci (9), and Fusobacterium sp (6). beta-lactamase activity was detected in at least one isolate in 20 (37%) of the 54 tested patients. These included all 8 tested S aureus and 7 B fragilis group, 3 of 10 H influenzae, 2 of 4 B melaninogenicus group, and 1 of 2 Klebsiella pneumoniae. Most cases of S pneumoniae and H influenzae were associated with pneumonia. The recovery of anaerobic bacteria was mostly associated with the concomitant diagnosis of aspiration pneumonia, lung abscess, subdiaphragmatic abscess, and abscesses of dental or oropharyngeal origin. The data highlight the importance of anaerobic bacteria in selected cases of empyema in children and adolescents.

Adolescent↗
PubMed1990

Quinolone therapy of Klebsiella pneumoniae sepsis following irradiation: comparison of pefloxacin, ciprofloxacin, and ofloxacin.

Exposure to whole-body irradiation is associated with fatal gram-negative sepsis. The effect of oral therapy with three quinolones, pefloxacin, ciprofloxacin, and ofloxacin, for orally acquired Klebsiella pneumoniae infection was tested in B6D2F1 mice exposed to 8.0 Gy whole-body irradiation from bilaterally positioned 60Co sources. A dose of 10(8) organisms was given orally 2 days after irradiation, and therapy was started 1 day later. Quinolones reduced colonization of the ileum with K. pneumoniae: 16 of 28 (57%) untreated mice harbored the organisms, compared to only 12 of 90 (13%) mice treated with quinolones (P less than 0.005). K. pneumoniae was isolated from the livers of 6 of 28 untreated mice, compared to only 1 of 90 treated mice (P less than 0.001). Only 5 of 20 (25%) untreated mice survived for at least 30 days compared with 17 of 20 (85%) mice treated with ofloxacin, 15 of 20 (75%) mice treated with pefloxacin, and 14 of 20 (70%) treated with ciprofloxacin (P less than 0.05). These data illustrate the efficacy of quinolones for oral therapy of orally acquired K. pneumoniae infection in irradiated hosts.

Animals↗
PubMed1990

Bacteremia due to anaerobic bacteria in newborns.

Awareness of the role of anaerobic bacteria in neonatal bacteremia has increased in recent years. The incidence of recovery of anaerobes in neonatal bacteremia varies, according to different studies, between 1.8% and 12.5%. Of the 178 cases reported in the literature, 73 were due to Bacteroides species (69 were the Bacteroides fragilis group), 57 Clostridium species (mostly Clostridium perfringens), 35 Peptostreptococci, 5 Propionibacterium acnes, 3 Veillonella species, 3 Fusobacterium species, and 2 Eubacterium species. Predisposing factors were perinatal maternal complications (especially premature rupture of membranes and chorioamnionitis), prematurity, and necrotizing enterocolitis. Organisms similar to those recovered in blood were concomitantly isolated in lung aspirates and cerebrospinal and peritoneal fluids. The overall mortality noted is 26% and is highest with B fragilis group (34%). Inappropriate antimicrobial therapy was often a contributory factor for such mortality. Correction of underlying pathology, surgical drainage, and the use of proper antimicrobials are critical to successful resolution of the infection. Penicillin G is the drug of choice for anaerobic infection other than beta-lactamase-producing Bacteroides. Antimicrobials useful for therapy of beta-lactamase-producing Bacteroides include clindamycin, metronidazole, chloramphenicol, imipenem-cilastatin, and the combination of a penicillin plus a beta-lactamase inhibitor.

Bacteria, Anaerobic↗
PubMed1989

Penicillin and clindamycin therapy in recurrent tonsillitis. Effect of microbial flora.

Fifty patients, scheduled for an elective tonsillectomy because of recurrent group A beta-hemolytic streptococcal tonsillitis, participated in a prospective randomized study that compared the efficacy of presurgical treatment with either phenoxymethyl penicillin or clindamycin hydrochloride in eradicating group A beta-hemolytic streptococci and beta-lactamase-producing bacteria (BLPB) from the tonsillar core. They were randomized into three groups as follows: 11 received penicillin, 22 received clindamycin, and 17 received no therapy. Group A beta-hemolytic streptococci were isolated from 8 (40%) of 17 untreated patients, 4 (36%) of 11 patients treated with penicillin, and none of 22 patients treated with clindamycin. Twenty-one BLPB were isolated from 16 (94%) of 17 untreated patients, 11 BLPB from 9 (82%) of 11 patients treated with penicillin, and 7 BLPB from 7 (32%) of 22 patients treated with clindamycin compared with penicillin or no therapy. Of the 22 patients treated with clindamycin, 10 were younger than 12 years of age. The BLPB were eradicated in nine patients (90%). However, BLPB were eradicated only in 6 (50%) of the 12 patients who were aged 13 years and older. These data illustrate the efficacy of clindamycin therapy in eradicating group A beta-hemolytic streptococci, as well as BLPB, in recurrent inflamed tonsils, especially in persons aged 12 years old and younger.

Adolescent↗
PubMed1989

Effect of encapsulated Bacteroides asaccharolyticus and Bacteroides fragilis on the growth of aerobic and facultative bacteria in mixed infections.

The effects of encapsulation of Bacteroides asaccharolyticus and Bacteroides fragilis on aerobic or facultative bacteria were evaluated using a subcutaneous abscess model in mice. The change in number of aerobic and facultative bacteria (AFB) was studied by comparing their number when injected with nonencapsulated, encapsulated Bacteroides species, and capsular material of Bacteroides species. In 14 combinations of AFB mixed with nonencapsulated Bacteroides species, an increase in the number of nonencapsulated Bacteroides species and an increase in the number of AFB occurred in two instances. An increase in the number of AFB occurred in 11 of the 14 combinations with encapsulated Bacteroides species. No change in the bacterial numbers was observed when the AFB were inoculated with capsular material of Bacteroides species. These data demonstrate the ability of viable encapsulated Bacteroides species to enhance the growth of aerobic or facultative bacteria.

Abscess↗
PubMed1989

Anaerobic bacteria in suppurative genitourinary infections.

Bacterial growth was obtained from specimens of 55 male and 48 female patients with localized suppurative genitourinary tract infections. The 55 male patients had abscesses of the genitalia (15), scrotal cyst (3), penis (7), testis (6), prostate (3), kidney (4), perinephric area (2) and periurethral area (4), wounds of the scrotum (3) and penis (6), and infected hydrocele (2). The 48 female patients had abscesses of Bartholin's cyst (26), vulva (4), vagina (4), labial cyst (2), kidney (2), perinephric area (1), periurethral area (3) and bladder (2), and a labial wound (4). Anaerobic bacteria only were present in 34 specimens (33 per cent), aerobic bacteria only in 7 (7 per cent), and mixed aerobic and anaerobic flora in 62 (60 per cent). A total of 275 isolates (189 anaerobic and 86 aerobic) was recovered, for an average of 2.6 isolates per specimen (1.8 anaerobes and 0.8 aerobes). The predominant anaerobes recovered were Bacteroides species (103 isolates) and anaerobic cocci (54). The most frequently recovered aerobes were Escherichia coli (26 isolates), Staphylococcus aureus (10) and Proteus species (8). These data illustrate that most suppurative genitourinary infections involve anaerobic bacteria. These findings have important implications regarding the culturing techniques of these infections and for the selection of antimicrobials for their management.

Abscess↗
PubMed1989

Treatment of wound sepsis in irradiated mice.

Infections in the immunocompromised host are difficult to treat. The local and systemic effect of penicillin therapy, supplemented by immunoglobulins, and pentoxifylline on wounds infected by Staphylococcus aureus was evaluated in mice irradiated with 6.5 Gy 60Co gamma-rays. Three days after irradiation a suspension of S. aureus was inoculated subcutaneously over the gluteus muscle of anesthetized mice. The skin and the muscle were incised at the site of the inoculation. Treatment with 62.5 mg/kg penicillin-G was administered for 10 days. Numbers of bacteria per mg muscle and presence of organisms in spleens and livers were determined. Numbers of bacteria were significantly reduced from 7.3 (+/- 0.3) to 5.3 (+/- 0.4) log10 CFU/mg (+/- SEM) muscle in treated animals. Administration of immunoglobulin G i.v. or pentoxifylline i.p. alone, or in addition to penicillin-G, did not further reduce the number of bacteria. Increase in the dose of penicillin to 250 mg/kg decreased the number of bacteria more than 62.5 mg/kg. Bacteria were recovered from spleens and/or livers of all 13 untreated mice, and only in six of the 13 penicillin-treated mice (P less than 0.05). Penicillin therapy reduced the systemic spread of S. aureus. The model provides a means to evaluate regimens for treatment of bacterial wound infections in irradiated animals. The data illustrated the ability of antimicrobial agents to contain but not cure the infection in the immunocompromised host, and the lack of efficacy of immunoglobulins in neutropenic mice.

Animals↗
PubMed1989

In vitro susceptibility and in vivo efficacy of antimicrobials in the treatment of Bacteroides fragilis-Escherichia coli infection in mice.

Cefamandole, cefoxitin, cefotetan, ceftizoxime, imipenem plus cilastatin, and ampicillin plus sulbactam were compared in the eradication of subcutaneous abscess in mice caused by Bacteroides fragilis group organisms and Escherichia coli alone or in combination. The abscesses were examined 5 d after inoculation. B. fragilis group reached log10.1-11.0 organisms per abscess and E. coli log11.6-12.5. Imipenem plus cilastatin significantly reduced (in 6.9-10.6 logs) the number of E. coli and all members of B. fragilis group alone or in all combinations. Ampicillin plus sulbactam reduced the numbers of all B. fragilis group (in 4.2-7.2 logs) but was less effective against E. coli (reduction of 1.8-4.2 logs). Cefoxitin was effective in significantly reducing (in 4.9-6.2 logs) the number of E. coli and all members of B. fragilis group alone or in all combinations. Cefotetan was effective against B. fragilis (reduction of 5.1-6.6 logs) and E. coli alone or in combination but did not reduce the number of Bacteroides thetaiotaomicron, Bacteroides vulgatus, and Bacteroides ovatus. Ceftizoxime was effective against only B. ovatus (reduction of 3.7-5.8) and E. coli (reduction of 6.0-8.1 logs); it did not reduce the number of other organisms. Cefamandole was effective against only E. coli and was not effective against any member of the B. fragilis group. These in vivo data confirm the in vitro activity of these antimicrobials.

Abscess↗