Search PubMed⌕ Search

Biomedical subjects

I Brook

Publications and source records attributed to I Brook.

At least 145 records · Page 8Linked to original sources
PubMed1995

Quantitative bacteriology of tonsils removed from children with tonsillitis hypertrophy and recurrent tonsillitis with and without hypertrophy.

The aerobic and anaerobic bacterial species and their numbers were studied in tonsillar specimens from children who had undergone elective tonsillectomy: 6 patients with recurrent tonsillitis (RT), 9 with recurrent tonsillitis with hypertrophy (RTH), and 8 with obstructive tonsillar hypertrophy (OTH). Mixed flora were present in all tonsils, yielding an average of 6.7 isolates (5.6 aerobic or facultative and 1.1 anaerobic bacteria). The highest recovery rate of organisms per tonsil was in patients with OTH (7.7 per tonsil), compared to 6.3 per tonsil in RT and 5.9 per tonsil in RTH. The predominant aerobic and facultative organisms were Haemophilus influenzae (22 isolates), Neisseria sp (16), Staphylococcus aureus (14), and Eikenella corrodens (14), and the predominant anaerobic bacteria were Fusobacterium sp (8), Bacteroides sp (7), and Prevotella melaninogenica (5). The number of bacteria per gram of tonsillar tissue varied between 10(4) and 10(8). A higher concentration of S aureus and H influenzae was found in hypertrophic tonsils (RTH and OTH) as compared to RT. These findings suggest the presence of an increased bacterial load and supports an etiologic role for H influenzae and S aureus in hypertrophic tonsils with and without inflammation (RTH and OTH). Further studies to elucidate the effect of selective antimicrobial therapy directed at these organisms may offer an alternative management of hypertrophic tonsils.

Bacterial Infections↗
PubMed1995

Brain abscess in children: microbiology and management.

Brain abscess is a serious, life-threatening infection. The infection can originate from contiguous sites of existing infections, such as chronic otitis media, dental infection, mastoiditis, or sinusitis, where anaerobic bacteria predominate. The infection can also occur in children with cyanotic congenital heart disease, in whom the predominant organisms are viridans, microaerophilic, or anaerobic streptococci, or after head trauma, in which case Staphylococcus aureus, viridans cocci, and Streptococcus pneumoniae are the most prevalent isolates. Enterobacteriaceae, Pseudomonas aeruginosa, yeast, fungi, and mycobacteria are prevalent in the immunocompromised. Radioisotope brain scans, computed tomography, and magnetic resonance imaging are important tools that enable accurate diagnosis of the infection. Proper selection of antimicrobial with good intracranial penetration is essential in the management of intracranial infection. Delay in surgical drainage can be associated with high mortality or morbidity. However, brain abscess, especially in the early phase of cerebritis, may respond to antimicrobial therapy without surgical drainage.

Anti-Bacterial Agents↗
PubMed1995

Pneumonia in mechanically ventilated children.

The quantitative aerobic and anaerobic microbiology of bronchial aspirates, obtained using protective brush catheters, from 10 children with ventilator-associated pneumonia, is presented. Aerobic or faculative organisms only were isolated in 1 child, anaerobic bacteria only in 3, and aerobic mixed with anaerobic bacteria in 6. There were 10 aerobic or faculative and 17 anaerobic isolates. The predominant aerobes were Pseudomonas aeruginosa (2 isolates) and Klebsiella sp. (2). The predominant anaerobes were pigmented Prevotella and Porphyromonas species (5), Peptostreptococcus sp. (4), Fusobacterium sp. and B. fragilis group (2). A total of 10 beta-lactamase-producing aerobic and anaerobic bacteria were isolated in 8 patients. All patients except 1 responded to antimicrobial therapy directed against the recovered isolates. These data highlight the polymicrobial aerobic-anaerobic flora isolated from pulmonary specimens of patients with ventilator-associated pneumonia.

Adolescent↗
PubMed1995

Anaerobic infections in children with neurological impairments.

Children with neurological impairments are prone to develop serious infection due to anaerobic bacteria. They often are predisposed to develop infections caused by their own indigenous bacterial flora caused by impairments of their mechanical and immunological defenses, the change in their oral flora due to poor hygiene, and the delay in recognition of acute infection. The most common anaerobic infections are decubitus ulcers, gastrectomy site wound infections, pulmonary infections (aspiration pneumonia, lung abscesses, and tracheitis), and chronic suppurative otitis media. The unique microbiology of each of the infections and their medical and surgical management were discussed in this review.

Bacteria, Anaerobic↗
PubMed1994

Microbiology and management of chronic maxillary sinusitis.

OBJECTIVE: Assessment of the microbiology and management of patients who suffered from chronic maxillary sinusitis was studied retrospectively. DESIGN: Retrospective analysis of microbiology and antimicrobial therapy of 68 patients who underwent the Caldwell-Luc procedure for chronic sinusitis had not received antimicrobials before surgery and whose cultures showed bacterial growth. SETTING: This study was performed at the Naval Hospital in Bethesda, Md. INTERVENTION: Amoxicillin-clavulanic acid was given to 18 patients, amoxicillin or ampicillin to 25, cefaclor to 17, and erythromycin to eight. RESULTS: A total of 183 isolates (123 anaerobic and 60 aerobic) were recovered. Anaerobic organisms only were recovered from 35 (51%), specimens, and aerobic or facultative bacteria only in 12 (18%), and mixed aerobic and anaerobic flora in 21 (31%). Thirty-four aerobic and anaerobic beta-lactamase-producing bacteria were isolated from 28 patients. The 18 patients who received amoxicillin-clavulanic acid had the most rapid and complete response to therapy, none required a change in therapy, and surgical drainage was required in one case. Of 25 patients who received amoxicillin or ampicillin, eight required a change of therapy due to clinical failure (32%), including three who also had surgical drainage. Of 17 that received cefaclor, five had an antibiotic change (29%), one with surgical drainage. Of the eight who were treated with erythromycin, three needed antibiotic change (38%), two with surgical drainage. Resistant organisms were recovered from most of the patients that required therapeutic change. CONCLUSIONS: These findings indicate the major role of aerobic and anaerobic beta-lactamase-producing bacteria organisms in the polymicrobial etiology of chronic maxillary sinusitis and illustrate the superiority of therapy effective against these bacteria.

Adolescent↗
PubMed1994

Microbiology of tonsillar surfaces in infectious mononucleosis.

OBJECTIVE: To compare the cultures of tonsillar surface aerobic and anaerobic bacterial flora taken during the acute phase of infectious mononucleosis with the repeated cultures taken 2 months later. PATIENTS: Fourteen patients with pharyngotonsillitis associated with infectious mononucleosis. RESULTS: A total of 121 bacterial isolates (ie, 84 anaerobes and 37 facultatives and aerobes) were isolated in the acute stage, and 75 isolates (ie, 42 anaerobes and 33 aerobes) were recovered 2 months later. The reduction in the number of organisms in the second specimen was mostly due to the decrease in the recovery of Prevotella intermedia (13 in the first culture, compared with four in the second) and Fusobacterium nucleatum (12 vs four, respectively). CONCLUSIONS: The study illustrates that the surfaces of tonsils of patients with infectious mononucleosis contain more species of anaerobic organisms during the illness than following it. The potential role of these organisms in the inflammation process warrants further study.

Adolescent↗
PubMed1994

Are public library books contaminated by bacteria?

The microbial flora on the surfaces of 15 books obtained from a public library and from 15 books obtained from a family household were studied. Staphylococcus epidermidis was recovered from 4 of the library books and 3 of the family household books. The number of organisms per page was between one to four. This data illustrates the safety of using library books, as they do not serve as a potential source of transmission of virulent bacteria.

Books↗
PubMed1994

Microaerophilic streptococcal infection in children.

A total of 148 isolates of microaerophilic streptococci (MS) (47 Streptococcus constellatus, 43 Streptococcus intermedius and five Gemella morbillorum) were cultured from 123 children. There were predisposing conditions in 47 (38%) patients of which most common were previous surgery (14), trauma (11), malignancy (9) diabetes (6) and immunodeficiency (5). MS were the only bacteria isolated from 12 (10%) patients and mixed infections were encountered in 111, when the number of isolates varied between two and seven (average 3.0) isolates per specimen. The bacteria most commonly isolated with MS were anaerobic cocci (70 isolates), Bacteroides fragilis group (54), pigmented Prevotella and Porphyromonas (34) and Escherichia coli (26). Most B. fragilis and E. coli were recovered from intra-abdominal infections, and those of skin and soft tissue adjacent to the rectum. Most pigmented Prevotella and Fusobacteria were isolated from oropharyngeal, pulmonary, head and neck sites. Most MS were recovered from abscesses (43%), the abdominal cavity (17%), sinuses (10%) and chest infections (9%). Antimicrobial therapy was administered to all patients, in 61 this was combined with surgical drainage or correction. Three patients died. These data illustrate that MS can occasionally be associated with infection in children.

Abdomen↗
PubMed1994

Fusobacterial infections in children.

A total of 243 strains of Fusobacteria species was recovered from 226 of 1399 (16%) specimens obtained from 213 children. The strains included 65 (27%) Fusobacterium sp., 144 (59%) Fusobacterium nucleatum, 25 (10%) Fusobacterium necrophorum, five (2%) Fusobacterium varium, three (1%) Fusobacterium mortiferum, and one (0.4%) Fusobacterium gonidiaformans. Most Fusobacteria species were recovered from patients with abscesses (100), aspiration pneumonia (24), paronychia (15), bites (14), chronic sinusitis (ten), chronic otitis media (nine), and osteomyelitis (eight). Predisposing conditions were noted in 32 (15%) of the cases. These included immunodeficiency in nine (4%), steroid therapy in eight (4%), previous surgery in six (3%), diabetes in six (3%) and malignant neoplasms in five (2%). Fusobacteria sp. was the only isolate in 16 (8%) instances while mixed infections were encountered in 197 (92%) patients. The organisms most commonly isolated with Fusobacteria sp. were anaerobic cocci (155), pigmented Prevotella sp. and Porphyromonas sp. (95), Bacteroides fragilis group (80), Escherichia coli (43) and Bacteroides sp. (39). Most strains of B. fragilis group and E. coli were recovered from intra-abdominal infections and skin and soft tissue infections proximal to the rectal area. Most pigmented Prevotella sp. and Porphyromonas sp. were recovered from oropharyngeal and pulmonary sites and from sites around the head and neck. Antimicrobial therapy was administered to all patients; surgical drainage was performed in 85 (40%). All patients, except two who died, recovered. These findings illustrate the prevalence of Fusobacteria sp. associated with infections in children.

Adolescent↗
PubMed1994

Effect of antimicrobial therapy on the gastrointestinal bacterial flora, infection and mortality in mice exposed to different doses of irradiation.

The effect of antimicrobial therapy on gut flora, sepsis, and mortality was investigated in C3H/HeN female mice irradiated with 7.0, 8.0 or 8.5 Gy or 60Co. The antimicrobial agents tested were metronidazole, penicillin, imipenem, gentamicin and ofloxacin. In control mice, the greatest reduction of lactose fermenting organisms (1.7-2.8 logs) occurred on day 8 after irradiation and were related directly to radiation doses. After day 8, lactose fermenting organism levels increased and the increases were associated with mortality due to Enterobacteriaceae sepsis. Irradiation reduced the populations of strict anaerobic bacteria in control mice by 2-8 logs, and these remained at low levels. Treatment with either metronidazole or penicillin resulted in greater reductions of strict anaerobic bacteria than occurred in the controls and induced earlier and greater increases in lactose fermenting organisms and associated mortality. Therapies with either gentamicin or ofloxacin resulted in lesser reductions of strict anaerobic bacteria (1.1-2.2 logs) than occurred in controls, and caused greater decreases in lactose fermenting organisms and mortality. The changes in the bacterial flora and mortality following imipenem treatment were similar to controls. These data demonstrate that in animals exposed to irradiation, antimicrobial agents effective against strict anaerobic bacteria can be deleterious, but antimicrobial agents effective against lactose fermenting organisms may be beneficial.

Animals↗
PubMed1994

The treatment of irradiated mice with polymicrobial infection caused by Bacteroides fragilis and Escherichia coli.

The effects on the faecal flora and the efficacies of various antibiotic regimens administered as treatment for a mixed infection caused by Bacteroides fragilis and Escherichia coli in the irradiated host were investigated in a subcutaneous abscess model with C3H/HeN mice which had been exposed to 60Co. The regimens used included imipenem, ofloxacin, metronidazole and the combination of ofloxacin and metronidazole. The incidence of mortality associated with each regimen was as follows: 2 of 20 (10%) mice treated with ofloxacin; 16 of 20 (80%) given metronidazole (P < 0.05 compared with ofloxacin); 8 of 20 (40%) given imipenem (P < 0.05 compared with ofloxacin); 5 of 20 (25%) given the combination of ofloxacin and metronidazole (P = NS compared with ofloxacin); and 15 of 20 (75%) controls given a placebo (P < 0.05 compared with ofloxacin). Compared with the control group, the mean number of lactose-fermenting facultative anaerobes in the faeces of irradiated mice decreased significantly during treatment with either ofloxacin or ofloxacin combined with metronidazole; rose significantly from day 6 during treatment with metronidazole and was similar during treatment with imipenem. The numbers of strict anaerobes fell with all regimens (including the placebo) but, compared with the control group, were significantly higher in the ofloxacin and imipenem groups and significantly lower in the groups which received metronidazole (with or without ofloxacin). Imipenem and the combination of ofloxacin and metronidazole led to significant reductions in the numbers of cfu of both E. coli and B. fragilis in the abscesses compared with the placebo; ofloxacin alone caused a reduction in the number of cfu of E. coli only and metronidazole alone caused a reduction in the number of cfu of B. fragilis only. While the administration of metronidazole had a favourable effect on the B. fragilis component of the localized infection, there was a higher incidence of mortality with this agent, probably because it led to an increase in the number of Enterobacteriaceae in the faeces at the expense of a reduction in the number of strict anaerobes. Antimicrobial agents such as imipenem or the combination of a quinolone, such as ofloxacin, and metronidazole may be used successfully to treat localized infections in the irradiated host while avoiding potentially deleterious increases in the number of facultative anaerobes in the bowel.

Abscess↗
PubMed1994

Quinolone therapy in the prevention of endogenous and exogenous infection after irradiation.

The effect of oral therapy with 6 quinolones, lomefloxacin, ofloxacin, sparfloxacin, temafloxacin, CI-960, and CI-990 in the prevention of post-irradiation bacteraemia and mortality was tested in mice. Two models were used, the C3H/HeN mouse strain for endogenously acquired infection and the B6D2F1 mouse strain for studies of exogenously acquired Pseudomonas aeruginosa infection. Each therapy or water-fed control group included 40 mice, 20 for monitoring survival and 20 for obtaining liver cultures. In C3H/HeN mice, mortality in the groups that received each of the quinolones except CI-960 was significantly lower (P < 0.05) than in the water-treated mice. Survival was 54/60 (90%) with lomefloxacin 51/60 (85%) with ofloxacin, 50/60 (83%) with CI-990, 45/60 (75%) with sparfloxacin, 37/60 (62%) with temafloxacin, 9/60 (15%) for the control group, and 6/60 (10%) for CI-960. Enterobacteriaceae were isolated from 38 of 53 (72%) and Streptococcus spp. from 13 of 53 (25%) of the livers of control mice. The number of Enterobacteriaceae was lower in quinolone-treated mice. However, isolation of streptococci was similar to controls, except in those treated with sparfloxacin and CI-990. In B6D2F1 mice, mortality and isolation of P. aeruginosa in each of the quinolone group was significantly lower than for controls (P < 0.001). These data illustrate the efficacy of the quinolones in the therapy of exogenous infection, and the inability of those effective against anaerobic bacteria to prevent endogenous infection.

4-Quinolones↗
PubMed1994

Comparison of cefoxitin, cefotetan and the combination of ampicillin with sulbactam in the therapy of polymicrobial infection in mice.

The comparative efficacies of cefoxitin, cefotetan and the combination of ampicillin with sulbactam were investigated in mixed aerobic and anaerobic infections of mice. Treatment was administered by intramuscular injection for 10 days and was started 1 h before infection. After intraperitoneal infection with Escherichia coli, Bacteroides fragilis, and one other member of the B. fragilis group (either Bacteroides thetaiotaomicron, Bacteroides ovatus or Bacteroides distasonis), 41 of 90 (46%) control mice died and all survivors developed polymicrobial abscesses. Cephalosporin therapy reduced mortaligy 13% with cefoxitin, 3% with cefotetan, and 23% with ampicillin plus sulbactam; 14%, 10% and 14% of surviving animals, respectively developed abscesses. Each of the treatment regimens significantly reduced the number of all organisms in abscesses, independent of their activity in vitro. However, the reduction in the number of E. coli by ampicillin plus sulbactam was less marked (P < 0.001) than that achieved by cefoxitin (P < 0.05) or cefotetan. These data show that in vivo efficiencies of cefoxitin and cefotetan, are independent of their in vitro potencies in the early management of polymicrobial infections in mice.

Ampicillin↗
PubMed1994

Management of chronic suppurative otitis media: superiority of therapy effective against anaerobic bacteria.

The aerobic and anaerobic microbiology and management of 69 children who had chronic suppurative otitis media were studied retrospectively. A total of 188 isolates (103 anaerobic and 85 aerobic) were recovered. Anaerobic organisms alone were isolated from 11 (16%), aerobic bacteria only in 21 (30%) and mixed aerobic and anaerobic flora was present in 37 (54%). Forty-five beta-lactamase-producing bacteria were recovered from 60 (58%) patients. The most rapid time for resolution was noticed with clindamycin (8.3 +/- 0.6 days) (P < 0.001), as compared with ampicillin (12.0 +/- 0.8 days), erythromycin (16.5 +/- 1.6 days) and cefaclor (14.6 +/- 2.3 days). Resolution of the infection was achieved in 16 of 20 (80%) of those treated with clindamycin, 12 of 24 (50%) treated with ampicillin, 6 of 13 (46%) treated with erythromycin, and 4 of 12 (33%) treated with cefaclor. Organisms resistant to the antimicrobial used were recovered in 26 of 31 of patients who failed to respond to therapy. These findings indicate the role of resistant aerobic and anaerobic organisms in the polymicrobial etiology of chronic otitis media in children and illustrate the superiority of therapy effective against anaerobic bacteria.

Ampicillin↗
PubMed1994

The role of encapsulated anaerobic bacteria in synergistic infections.

The effect of encapsulation on the virulence, survival, and protection of anaerobic bacteria from phagocytosis is reviewed. Support for the importance of encapsulated Gram-negative anaerobic rods (Bacteroides sp., Prevotella sp. and Porphyromonas sp.), anaerobic and facultative Gram-positive cocci (AFGPC) was provided by their higher recovery rate in oropharyngeal infections, abscesses and blood, compared to their number in the normal flora. The pathogenicity of Bacteroides, Fusobacterium, Clostridium, and AFGPC was studied by inoculating them into mice and observing their ability to induce subcutaneous abscesses. Encapsulated Bacteroides, Fusobacteria, and AFGPC generally induced abscesses, whereas non-encapsulated organisms did not. However, many of the strains that had only a minimal number of encapsulated organisms (< 1%) survived in the abscesses, and they became heavily encapsulated when inoculated with other viable or non-viable encapsulated bacteria. Thereafter, these strains were able to induce abscesses when injected alone. Encapsulated Gram-negative anaerobic rods and AFGPC-induced bacteraemia and translocation, and increased the mortality of the infected animals more often than did the non-encapsulated form of the same strains. As determined by using selective antimicrobial therapy and quantitative cultures of abscesses induced in mice, possession of a capsule generally made Gram-negative anaerobic rods more important than their aerobic counterparts. Synergistic potentials were seen between encapsulated Gram-negative anaerobic rods and all tested aerobic bacteria and most AFGPC, and also between most AFGPC and Pseudomonas aeruginosa or Staphylococcus aureus. These studies demonstrated the importance of encapsulated anaerobes in mixed infections.

Abscess↗
PubMed1994

Infection caused by Propionibacterium in children.

Three hundred eighty-six isolates of Propionibacterium sp. were recovered from 2,003 specimens studied for the identification of anaerobic bacteria in children during a 15-year period. Three hundred forty-three (89%) of these were Propionibacterium acnes. A total of 50 (13%) Propionibacterium isolates identified from 45 patients were considered to cause infection. Clinically significant infections caused by Propionibacterium sp. were associated with bacteremia in 10 children; ear infection in eight; abscesses in seven; adenitis and central nervous system infection in five each; burns in four; wounds in three; tumors and bone in two each; and cysts, eye, sinus, and mastoid in one each. Predisposing or underlying conditions were present in 33 children (73%). These included the presence of a foreign body (17), immunodeficiency (six), malignancy (five), diabetes (five), previous surgery (four), and steroid therapy (two). Antimicrobial therapy was given to 41 (91%) children. Surgical drainage was concomitantly performed in 22 (49%). Four patients died. This study highlights the importance of Propionibacterium sp. as an unusual, but potentially important, pathogen in children.

Child↗
PubMed1994

Peptostreptococcal infection in children.

680 Peptostreptococcus sp. (Ps) were recovered from 598 (34%) of 1,750 specimens obtained from 554 patients. They included 103 Ps asaccharolyticus, 74 Ps magnus, 56 Ps prevotii, 51 Ps micros, 46 Ps anaerobius, 11 Ps morbilorum, and 10 Ps saccharolyticus. Most infections were polymicrobial (in 553 instances or 92%) but in 45 (8%), Ps were recovered in pure culture. Most Ps were isolated from abscesses (237), ears (104), peritoneal fluid (95), lung infections (66), bone (30) and sinuses (24). Predisposing conditions were present in 224 (40%) children. These were previous surgery (54), immunodeficiency (43), malignancy (35), trauma (34), diabetes (23), prematurity (22), steroid therapy (19), foreign body (10) and sickle-cell anemia (7). The organisms most commonly isolated with Ps were Bacteroides sp. (276, including 190 B. fragilis group), Prevotella sp. (159), Fusobacterium sp. (122), Escherichia coli (114), and Staphylococcus aureus (97). Antimicrobial therapy was administered to all but 14 patients. Surgical drainage or correction of pathology was performed in 307 (56%) patients. 10 patients (2%) died of their infection. These data illustrate the importance of Ps and suggests their enhancing potentials in infection in children.

Anti-Bacterial Agents↗