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Biomedical subjects

Itzhak Brook

Publications and source records attributed to Itzhak Brook.

At least 19 recordsLinked to original sources
PubMed2006

Isolation of methicillin resistant Staphylococcus aureus from the surface and core of tonsils in children.

BACKGROUND: The rate of recovery methicillin resistant Staphylococcus aureus (MRSA) in tonsils that were removed because of recurrent Group A-beta-hemolytic streptococci (GABHS) tonsillitis was not previously reported. MRSA may serve as a potential source for the spread of these organisms to other body sites as well to other individuals. This study investigated the rate of recovery of MRSA as well as other aerobic organisms from tonsils that were removed because of recurrent GABHS infection. PATIENTS AND METHODS: Core and surface tonsillar cultures for aerobic bacteria were obtained from 44 children who had tonsillectomy because of recurrent GABHS tonsillitis. RESULTS: A total of 167 aerobic isolates were recovered from the core of the tonsils (3.8/specimen) and 151 (3.4/specimen) were isolated from the surface. The predominant isolates were alpha-hemolytic streptococci, GABHS, S. aureus, gamma-hemolytic streptococci, Haemophilus influenzae and Moraxella catarrhalis. Concordance in the recovery of all organisms was noted in 117 instances. Certain organisms (i.e. GABHS, S. aureus) were recovered more often from the tonsillar cores, where other (i.e. alpha-hemolytic streptococci, gamma-hemolytic streptococci) were recovered more often from the tonsillar surface. Forty-four beta-lactamase-producing bacteria (BLPB) were recovered from 32 (75%) of the tonsillar cores, and 28 were isolated from 23 (52%) of the tonsillar surfaces. The predominant BLPB were S. aureus, H. influenzae and M. catarrhalis. Seven isolates of MRSA were recovered from the cores and two were isolated from the surface. Five of the core isolates and the two surface isolates were also BLPB. All of the MRSA isolates were resistant to oxacillin, penicillin and erythromycin and were susceptible to clindamycin, trimethoprim-sulfamethoxazole and vancomycin. CONCLUSIONS: These data demonstrated that in recurrently GABHS infected tonsils, BLPB was recovered from over 75% of the tonsillar cores, core tonsillar cultures yielded more GABHS and S. aureus, and MRSA was isolated from 16% of the tonsils.

Adolescent↗
PubMed2006

In vitro effects of penicillin and telithromycin on the expression of Streptococcus pneumoniae capsule.

OBJECTIVE: To evaluate the effects of subinhibitory concentrations of penicillin and telithromycin on capsular formation by Streptococcus pneumoniae. METHODS: A total of 60 isolates of S. pneumoniae, 20 susceptible, 20 intermediately resistant and 20 resistant to penicillin, were studied. All isolates were susceptible to telithromycin. RESULTS: All isolates were capsulate when grown without antibiotics. Encapsulation was lower after incubation with telithromycin as compared with penicillin in isolates susceptible to penicillin (20% versus 75%), in those intermediately resistant to penicillin (25% versus 95%) and in isolates fully resistant to penicillin (15% versus 100%) (P < 0.01). CONCLUSIONS: Telithromycin appears to be superior to penicillin in reducing the expression of the capsule by S. pneumoniae.

Anti-Bacterial Agents↗
PubMed2006

Bacteriology of chronic sinusitis and acute exacerbation of chronic sinusitis.

OBJECTIVE: To establish the microbiological characteristics of acute exacerbation of chronic sinusitis (AECS). SETTING: Academic medical center. PATIENTS: Thirty-two patients with chronic sinusitis and 30 patients with AECS. MAIN OUTCOME MEASURE: The aerobic and anaerobic microbiology of maxillary AECS and chronic maxillary sinusitis. RESULTS: A total of 81 isolates (33 aerobic and 48 anaerobic) were recovered from the 32 cases (2.5 per specimen) with chronic sinusitis. Aerobes alone were recovered in 8 specimens (25%), anaerobes only were isolated in 11 (34%), and mixed aerobes and anaerobes were recovered in 13 (41%). The predominant aerobic and facultative bacteria were Enterobacteriaceae and Staphylococcus aureus. The predominant anaerobic bacteria were Peptostreptococcus subspecies, Fusobacterium subspecies, anaerobic gram-negative bacilli, and Propionibacterium acnes. Twenty-one beta-lactamase-producing bacteria were recovered from 17 specimens (53%). A total of 89 isolates (40 aerobic and facultatives, and 49 anaerobic) were recovered from the 30 patients (3.0 per specimen) with AECS. Aerobes were recovered in 8 instances (27%), anaerobes only in 11 (37%), and mixed aerobes and anaerobes were recovered in 11 (37%). The predominant aerobes were Streptococcus pneumoniae, Enterobacteriaceae, and S aureus. The predominant anaerobes were Peptostreptococcus subspecies, Fusobacterium subspecies, anaerobic gram-negative bacilli, and P acnes. Thirty-six beta-lactamase-producing bacteria were recovered from 28 specimens (53%). CONCLUSIONS: This study demonstrates that the organisms isolated from patients with AECS were predominantly anaerobic and were similar to those generally recovered in patients with chronic sinusitis. However, aerobic bacteria that are usually found in acute infections (eg, S pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis) can also emerge in some of the episodes of AECS.

Acute Disease↗
PubMed2006

Effect of telithromycin and azithromycin on nasopharyngeal bacterial flora in patients with acute maxillary sinusitis.

OBJECTIVE: To explore the efficacy of the ketolide telithromycin compared with azithromycin in eradicating S pneumoniae from the nasopharynx of adults with acute maxillary sinusitis. The growing resistance of Streptococcus pneumoniae to penicillin and macrolides brought about the development of a new class of antibiotics-the ketolides-that are effective against resistant pneumococci. SETTING: Otolaryngology clinic. PATIENTS: One-hundred five patients with acute maxillary sinusitis. INTERVENTIONS: Nasopharyngeal cultures were obtained before therapy and 10 to 12 days after initiation of treatment. Fifty-nine patients were treated with 500 mg of azithromycin daily for 3 days and 46 were treated with 800 mg of telithromycin daily for 5 days. RESULTS: Sixty-seven potential pathogens were recovered prior to initiation of therapy in 57 patients, 32 treated with telithromycin and 25 treated with azithromycin: S pneumoniae (31 isolates), Haemophilus influenzae (non-type b) (13), Staphylococcus aureus (8), Streptococcus pyogenes (8), and Moraxella catarrhalis (7). The distribution of the pathogens was similar in both groups. The number of S pneumoniae isolates in the azithromycin group was reduced following treatment from 14 to 8 (43% reduction), and 5 of these 8 isolates were resistant to azithromycin. In contrast, the number of S pneumoniae isolates in the telithromycin group was reduced following treatment from 17 to 1 (94% reduction) (P < .01). This isolate was susceptible to azithromycin and telithromycin. No differences were noted in the eradication rate of all of the other potential pathogens, which were all susceptible to both azithromycin and telithromycin. Development of resistance to the antimicrobial agents used (defined as increase in the minimal inhibitory concentration by at least 2 tubes) was found only in 5 isolates (4 S pneumoniae and 1 H influenzae) recovered only from patients who received azithromycin (P < .05). CONCLUSION: These data illustrate the superiority of telithromycin to azithromycin in the eradication of S pneumoniae from the nasopharynx.

Acute Disease↗
PubMed2006

Sinusitis of odontogenic origin.

Odontogenic sinusitis is a well-recognized condition and accounts for approximately 10% to 12% of cases of maxillary sinusitis. An odontogenic source should be considered in individuals with symptoms of maxillary sinusitis with a history of odontogenic infection, dentoalveolar surgery, periodontal surgery, or in those resistant to conventional sinusitis therapy. Diagnosis usually requires a thorough dental and clinical evaluation including appropriate radiographs. The most common causes of odontogenic sinusitis include dental abscesses and periodontal disease that had perforated the Schneidarian membrane, irritation and secondary infection caused by intra-antral foreign bodies, and sinus perforations during tooth extraction. An odontogenic infection is a polymicrobial aerobic-anaerobic infection, with anaerobes outnumbering the aerobes. The most common isolates include anaerobic streptococci and gram-negative bacilli, and Enterobacteriaceae. Surgical and dental treatment of the odontogenic pathological conditions combined with medical therapy is indicated. When present, an odontogenic foreign body should be surgical removed. Surgical management of oroantral communication is indicated to reduce the likelihood of causing chronic sinus disease. The management of odontogenic sinusitis includes a 3- to 4-week course of antimicrobials effective against the oral flora pathogens.

Combined Modality Therapy↗
PubMed2006

Disease severity in acute bacterial rhinosinusitis is greater in patients infected with Streptococcus pneumoniae than in those infected with Haemophilus influenzae.

BACKGROUND: Streptococcus pneumoniae and Haemophilus influenzae are the most common causative pathogens in acute bacterial rhinosinusitis. A post hoc pooled analysis of four multinational Phase III clinical trials was conducted to compare disease severity in acute bacterial rhinosinusitis caused by S. pneumoniae or H. influenzae. METHODS: Patients were evaluated for acute bacterial rhinosinusitis clinician-assessed symptom severity and radiologic findings (total opacity, mucosal thickening, and air-fluid levels on maxillary sinus x-rays). Specimens for bacteriologic identification were collected by maxillary sinus tap, or by selective middle meatal cultures (sinus aspirates or swabs). RESULTS: Compared with patients infected with H. influenzae (n = 106), patients infected with S. pneumoniae (n = 143) showed a statistically significant higher incidence of severe disease (39.2% vs 23.6%, P = 0.0097) and total opacity (46.2% vs 29.2%, P = 0.0085). Mucosal thickening (47.6% vs 56.6%, P = 0.1616) and air-fluid levels (49% vs 56.6%, P = 0.2500) were comparable between the two groups. CONCLUSIONS: In acute bacterial rhinosinusitis, infection with S. pneumoniae is associated with more severe clinical symptoms and radiographic total opacification findings than infection with H. influenzae.

Acute Disease↗
PubMed2006

Increased recovery of Moraxella catarrhalis and Haemophilus influenzae in association with group A beta-haemolytic streptococci in healthy children and those with pharyngo-tonsillitis.

The inflamed tonsils harbour numerous types of bacteria, alone or in combination with group A beta-haemolytic streptococci (GABHS). The cohabitation of the tonsils by GABHS and certain other bacterial species may contribute to the inflammatory process and the failure of penicillin therapy. This study evaluated the recovery of Moraxella catarrhalis, Haemophilus influenzae, Staphylococcus aureus and Streptococcus pneumoniae in association with GABHS in healthy children and those with acute pharyngo-tonsillitis (APT). Pharyngo-tonsillar cultures were obtained from 548 children with APT and 866 healthy children. GABHS was recovered from 112 (20.4%) children with APT. Of the 114 H. influenzae isolates, 32 were recovered in association with GABHS (29% of all patients who had GABHS) and 82 were isolated without GABHS (19%) (P=0.0267). Of the 69 M. catarrhalis isolates, 25 were recovered in association with GABHS (22% of all patients who had GABHS) and 44 were isolated without GABHS (10%) (P=0.0012). In contrast, there was no association between the isolation of GABHS and the recovery of Staph. aureus or Strep. pneumoniae. GABHS was recovered from 104 (12%) healthy children. Of the 69 M. catarrhalis isolates, 24 were recovered in association with GABHS (23% of all patients who had GABHS) and 80 were isolated without GABHS (10%) (P=0.006). There was no association between the isolation of GABHS and the recovery of H. influenzae, Staph. aureus or Strep. pneumoniae. This study demonstrates an association between the recovery of GABHS and H. influenzae and M. catarrhalis from pharyngo-tonsillar cultures of patients with APT and M. catarrhalis from pharyngo-tonsillar cultures of healthy children.

Acute Disease↗
PubMed2006

Frequency of recovery of pathogens causing acute maxillary sinusitis in adults before and after introduction of vaccination of children with the 7-valent pneumococcal vaccine.

The objective of the study was to compare the proportions of the recovery of pathogens of acute maxillary sinusitis in adults in the 4-year period prior to the 5-year period that followed the introduction of vaccination of children with the 7-valent pneumococcal vaccine (PCV7). Cultures were obtained through endoscopy from 385 adults with acute maxillary sinusitis, 156 between 1997 and 2000, and 229 between 2001 and 2005. One hundred and seventeen potentially pathogenic organisms were isolated from the cultures obtained between 1997 and 2000. The predominant organisms were Streptococcus pneumoniae (54 or 46 % of all isolates), Haemophilus influenzae non-type b (42 or 36 %), Moraxella catarrhalis (7 or 6 %), Streptococcus pyogenes (8 or 7 %) and Staphylococcus aureus (6 or 5 %). One hundred and sixty-seven potentially pathogenic organisms were isolated from the cultures obtained between 2001 and 2005. The most predominant organisms were H. influenzae non-type b (71 or 43 % of all isolates), Strep. pneumoniae (58 or 35 %), M. catarrhalis (13 or 8 %), Strep. pyogenes (12 or 7 %) and Staph. aureus (13 or 8 %). Significant statistical differences were noted in the rates of recovery of H. influenzae non-type b (P < 0.05) and Strep. pneumoniae (P < 0.05). A decrease occurred in the recovery of Strep. pneumoniae resistant to penicillin from 41 to 29 %, and an increase was noted in the isolation of beta-lactamase-producing H. influenzae from 33 to 39 %; however, neither change was statistically significant. These data illustrate that a significant shift occurred in the causative pathogens of acute maxillary sinusitis in adults in the 5 years after the introduction of vaccination of children with the PCV7 compared to the previous 4 years.

Adult↗
PubMed2006

Recovery of interfering and beta-lactamase-producing bacteria from group A beta-haemolytic streptococci carriers and non-carriers.

The purpose of this study was to compare the frequency of recovery of aerobic and anaerobic organisms with interfering capability against group A beta-haemolytic streptococci (GABHS) and beta-lactamase-producing bacteria (BLPB) from the tonsils of GABHS carriers and non-carriers. The presence of aerobic and anaerobic bacteria capable of such interference in vitro was evaluated in cultures obtained from the tonsils of 20 healthy children who were non-GABHS carriers and 20 who were GABHS carriers, and also from 20 children who were asymptomatic after completing a course of penicillin for acute GABHS pharyngo-tonsillitis (PT) and were non-GABHS carriers and 20 who were GABHS carriers. In healthy children, 32 interfering isolates were recovered from 16 non-GABHS carriers (1.6 per child) and 13 were isolated from 7 GABHS carriers (0.65 per child) (P<0.001). In children who had suffered acute GABHS PT, 26 interfering organisms were recovered from 15 non-GABHS carriers (1.3 per child) and 8 were isolated from 5 GABHS carriers (0.4 per child) (P<0.005). In healthy children, 13 BLPB were recovered from 5 non-GABHS carriers and 13 were isolated from 6 GABHS carriers. In children who had suffered acute GABHS PT, 14 BLPB were recovered from 5 (25 %) non-GABHS carriers and 32 were isolated from 17 (85 %) GABHS carriers (P<0.05). It was demonstrated in this study that there was a higher rate of recovery of aerobic and anaerobic organisms capable of interfering with GABHS in non-GABHS carriers than in GABHS carriers. This was observed in all GABHS non-carriers and included healthy children as well as those recently treated for symptomatic GABHS PT with penicillin that failed to eradicate GABHS. A higher rate of recovery of BLPB was observed only in GABHS carriers who were treated with penicillin for GABHS PT.

Aerobiosis↗
PubMed2006

Microbiology of intracranial abscesses associated with sinusitis of odontogenic origin.

OBJECTIVES: The unique microbiology of sinusitis of dental origin that is associated with intracranial abscesses (IAs) and the correlation between the organisms at the two sites has not been reported before. This report describes the author's experience during a 30-year period in studying the microbiology of 8 IAs and their corresponding sinusitis of dental origin. METHODS: Aspirates of pus from 8 infected sinuses associated with odontogenic infections and their corresponding IAs were studied for aerobic and anaerobic bacteria. Polymicrobial flora was found in all 8 sinuses and 7 IAs, and the number of isolates varied from 1 to 5. RESULTS: Anaerobic bacteria were isolated from all sinuses and IAs. A total of 28 isolates (3.5 isolates per site; 25 strict anaerobic, 1 aerobic or facultative, and 2 microaerophilic) were recovered from the sinuses, and 20 isolates (2.5 isolates per site; 16 strict anaerobic, 1 aerobic or facultative, and 3 microaerophilic) were found in the IAs. The bacterial isolates were Fusobacterium spp (14), Prevotella spp (11), Peptostreptococcus spp (13), microaerophilic streptococci (5), Veillonella parvula (3), and beta-hemolytic streptococci group F(2). Concordance in the microbiological findings between the sinus and the IA was found in all instances; however, certain organisms were only present at one site. CONCLUSIONS: These data illustrate the concordance in the organisms recovered from sinusitis of dental origin and their associated IAs and confirm the importance of anaerobic bacteria in sinusitis and IAs of dental origin.

Adult↗
PubMed2006

The role of anaerobic bacteria in mediastinitis.

The management of mediastinitis involves directing appropriate antibacterial therapy against the potential bacterial pathogens. The increased recovery of anaerobic bacteria from mediastinal infections has led to a greater appreciation of their role in this condition and to re-evaluation of the proper treatment of this condition. Mediastinitis caused by anaerobic bacteria generally emerges following perforation of the oesophagus, extension of retropharyngeal abscess, suppurative parotitis, cervical cellulitis or abscess of dental origin. The bacteria recovered from these infections are often of oral origin and involve mixed aerobic-anaerobic oral flora. The predominant anaerobic isolates include Bacteroides spp., Peptostreptococcus spp., pigmented Prevotella and Porphyromonas spp. and Fusobacterium spp. Treatment includes surgical intervention, antibacterial therapy and supportive measures. Appropriate management of mediastinal infections due to aerobic and anaerobic infections requires the administration of antibacterials that are effective against both the aerobic and anaerobic components of the infection. Selection of antibacterials for the treatment of mediastinitis is determined by bacteriological studies.

Aminoglycosides↗
PubMed2006

Management of group A beta-hemolytic streptococcal pharyngotonsillitis in children.

Acute pharyngotonsillitis is one of the most common infections encountered by pediatricians and family physicians. According to the US Vital Health Statistics report, acute pharyngotonsillitis is responsible for more than 6 million office visits each year by children younger than 15 years of age and an additional 1.8 million visits by adolescents and young adults aged 15 to 24 years. Most children with acute pharyngotonsillitis have symptoms that can be attributed to infection with a respiratory virus, such as adenovirus, influenza virus, parainfluenza virus, rhinovirus, and respiratory syncytial virus. However, in approximately 30% to 40% of cases, acute pharyngotonsillitis is of bacterial etiology. Group A beta-hemolytic streptococci (GABHS) are responsible for most bacterial cases of acute pharyngotonsillitis, although other pathogens, such as Neisseria gonorrhoeae, Arcanobacterium haemolyticum, Mycoplasma pneumoniae, and Chlamydia pneumoniae, may be the causative agents in sporadic cases. Pharyngotonsillitis caused by these latter pathogens can sometimes be distinguished from that caused by GABHS by considering the patient's medical history in concert with the clinical presentation. In some cases, acute pharyngotonsillitis may have an idiopathic etiology. An accurate diagnosis of GABHS infection is important because it is the only common form of acute pharyngotonsillitis for which antibiotic therapy is definitely indicated. Antibiotic therapy can shorten the clinical course of GABHS pharyngotonsillitis, reduce the rate of transmission, and prevent suppurative and nonsuppurative complications, such as peritonsillar abscess and acute rheumatic fever. Although the threat of rheumatic fever is much lower for children in the United States than in developing nations, preventing rheumatic fever and the spread of disease is the primary goal of antibiotic therapy in GABHS pharyngotonsillitis treatment and a cornerstone of practice guidelines.

Acute Disease↗
PubMed2006

Botulism: the challenge of diagnosis and treatment.

Botulism is a rare paralytic disease caused by a neurotoxin produced from the spore-forming bacterium Clostridium botulinum and in rare cases Clostridium butyricum and Clostridium baratii. Botulism has 4 naturally occurring syndromes: foodborne, wound, infant botulism, and adult intestinal toxemia. Inhalational botulism could result from aerosolization of botulinum toxin, and iatrogenic botulism can result from injection of toxin. All of these produce the same clinical syndrome of symmetrical cranial nerve palsies followed by descending, symmetric flaccid paralysis of voluntary muscles, which may progress to respiratory compromise and death. Treatment includes meticulous intensive care that includes mechanical ventilation, when necessary, and administration of antitoxin.

Botulinum Toxins↗
PubMed2005

The role of anaerobic bacteria in sinusitis.

The normal oropharyngeal flora contained aerobic and anaerobic bacteria that can cause respiratory infections including sinusitis. Some of these bacteria can interfere with the growth of potential pathogens and may play a role in preventing infections. Anaerobic bacteria emerge as pathogens as the infection becomes chronic. This may be the result of the selective pressure of antimicrobial agents that enable resistant anaerobic organisms to survive, and from the development over time of conditions appropriate for anaerobic growth, which include the reduction in oxygen tension and an increase in acidity within the sinus cavity. Anaerobes were isolated in acute maxillary sinusitis of odontogenic origin and in over half of the patients with chronic sinusitis whenever proper techniques for their cultivation were employed. These organisms were also recovered in acute sinusitis that was associated with dental infections. The predominant isolates were pigmented Prevotella and Porphyromonas, Fusobacterium and Peptostreptococcus spp.

Acute Disease↗
PubMed2005

Eradication of pathogens from the nasopharynx after therapy of acute maxillary sinusitis with low- or high-dose amoxicillin/clavulanic acid.

The growing resistance of Streptococcus pneumoniae to penicillin can be overcome by increasing the dose of the penicillin administered. This generated the recommendation that the adult dose of amoxicillin for the treatment of acute maxillary sinusitis (AMS) be increased from 1.5 g/day to 4.0 g/day. The objective of this study was to investigate whether the higher dose of amoxicillin is more effective than the previously recommended dose in eradicating S. pneumoniae from the nasopharynx of patients who present with AMS. Nasopharyngeal cultures obtained from 58 patients with AMS were studied: 30 received amoxicillin 1.5 g/day given in divided doses three times a day for 10 days (amoxicillin/clavulanic acid 4:1 formulation) and 28 were treated with amoxicillin 4.0 g/day given in divided doses twice a day for 10 days (amoxicillin/clavulanic acid 16:1 formulation). Seventy-one potentially pathogenic organisms were isolated: S. pneumoniae (27 isolates), Haemophilus influenzae non-type b (25), Moraxella catarrhalis (5), Streptococcus pyogenes (5) and Staphylococcus aureus (9). The number of S. pneumoniae isolates in the 1.5 g/day group was reduced from 14 to 9 (2 intermediately resistant and 3 highly resistant). In contrast, the number of S. pneumoniae isolates in the 4.0 g/day group was reduced from 13 to 2 (1 highly resistant) (P<0.05). No differences were noted in the eradication rate of other groups of isolates, which were all susceptible to amoxicillin/clavulanic acid. These data illustrate the superiority of 4.0 g/day amoxicillin/clavulanic acid compared with 1.5 g/day amoxicillin/clavulanic acid in the eradication of S. pneumoniae from the nasopharynx.

Acute Disease↗