Microbiology of sinusitis

Most sinus infections are viral, and only a small proportion develops a secondary bacterial infection. Rhinoviruses, influenza viruses, and parainfluenza viruses are the most common causes of sinusitis. The most common bacteria isolated from pediatric and adult patients with community-acquired acute purulent sinusitis are Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pyogenes. Staphylococcus aureus and anaerobic bacteria (Prevotella and Porphyromonas, Fusobacterium and Peptostreptococcus spp.) are the main isolates in chronic sinusitis. Pseudomonas aeruginosa and other aerobic and facultative gram-negative rods are commonly isolated from patients with nosocomial sinusitis, the immunocompromised host, those with HIV infection, and in cystic fibrosis. Fungi and Pseudomonas aeruginosa are the most common isolates in neutropenic patients. The microbiology of sinusitis is influenced by the previous antimicrobial therapy, vaccinations, and the presence of normal flora capable of interfering with the growth of pathogens.     

Therapy of chronic recurrent respiratory tract infections

In 1987, the most frequently identified pathogens in chronic respiratory tract infections in our clinic were Haemophilus influenzae, Pseudomonas aeruginosa, Branhamella catarrhalis, Streptococcus pneumoniae, Staphylococcus aureus and Klebsiella pneumoniae. Recurrent infection is a common phenomenon in patients with chronic respiratory tract infections, including chronic bronchitis, chronic bronchiolitis and bronchiectasis. H. influenzae is the most common pathogen in such patients. Macrolides, tetracyclines and new quinolones were effective to protect against recurrent infection of H. influenzae and these finding suggested that L-forms of H. influenzae may be significant in the recurrence of infection in patients with chronic respiratory tract infection. Bacterial colonization of the oropharynx is the initial event in most lower respiratory tract infections. Gargling protects against bacteria colonization of the oropharynx and occurrence of acute exacerbation.     

Bacteria isolated from chronic upper and lower respiratory tract infections and the associated therapeutic strategies--in paranasal sinusitis

Nasal sinusitis, tonsillitis, and pharyngolaryngitis typify upper respiratory tract infections, while bronchitis and pneumonia typify lower respiratory tract infections. Cases of paranasal sinusitis with severe suppuration are reportedly becoming less frequent, while those of chronic catarrhal paranasal sinusitis and edematous allergic paranasal sinusitis are becoming more so, The primary factor in paranasal sinusitis, a typical infectious disease encountered in otolaryngology, is bacterial infection. The main causative bacteria are Streptococcus pneumoniae, reported in 13.4% of cases, Haemophilus influenzae in 12.8% Moraxella catarrhalis in 5.5%, Staphylococcus aureus in 26.5%, Pseudomonas aeruginosa in 5.2%, and anaerobes. The incidence of strains resistant to antimicrobial agents has grown for S. pneumoniae, H. influenzae, and M. catarrhalis and decreased for S. aureus and P. aeruginosa. Acute exacerbation or severe suppuration in chronic paranasal sinusitis requires the administration of antimicrobial agents, with the same agent administered 2 weeks for maximal effect. First-line agents are AMPC/CVA, SBTPC, CDTR-PI, CFPN-PI, and GFLX for adults, with ASPC, SBPC, ACPC, CTRX, CMZ, FMOX, PAPM/BP, and MEPM injected in severe cases. Attention must be paid to strains that resist cephems and macrolides, such as PISP, PRSP, and BLNAR. In refractory chronic paranasal sinusitis, attention must also be paid to biofilms produced by S. aureus and P. aeruginosa. Suitable antimicrobial agents should be determined for treating of chronic paranasal sinusitis, in addition to the best procedure to ensure early recovery from inflammation, such as puncturing or irrigating the maxillary sinus, injecting a suitable agent, nebulization, and/or surgically widening the middle meatus.     

Antimicrobial treatment of otitis media.

The major pathogens causing acute otitis media (AOM) are Streptococcus pneumoniae and Haemophilus influenzae, with Moraxella catarrhalis, Streptococcus pyogenes, and Staphylococcus aureus less frequently isolated. The same organisms and Staphylococcus epidermidis are found in chronic otitis media with effusion. In chronic suppurative otitis media, Pseudomonas aeruginosa and S aureus are most frequently found. Antimicrobial agents found to be most effective in treating AOM are amoxicillin, trimethoprimsulfamethoxazole, erythromycin-sulfisoxazole, amoxicillin-clavulanate, and cefaclor. Cefuroxime axetil and cefixime are alternatives for which there are less data. Currently, about 20% of AOM cases are caused by beta-lactamase-producing strains (usually H influenzae or M catarrhalis) that are resistant to amoxicillin, thus favoring the use of the other agents listed. Concentrations of antibiotics in middle ear infections range from 10% to 76% of peak serum levels for the listed agents and are higher in AOM than in chronic otitis media with effusion, emphasizing the importance of adequate dosing for successful treatment.     

Studies on respiratory infections in primary care clinic (II). Distribution and antibiotic sensitivity to 45 agents of bacteria isolated from patients with respiratory infections visiting a doctor in private practice

The bacteriology of the isolates from the sputum or the throat swab of patients with respiratory infections visiting a doctor in private practice in Sendai city during the period from March in 1988 to February in 1989 was documented, and their sensitivity to 45 antimicrobial agents was determined. Of the 568 patients, 514 cases had acute pharyngitis, 8 cases each had acute tonsillitis and acute bronchitis, 7 cases were acute pneumonia, 6 cases had herpangina, 18 cases had hand-foot-mouth disease with the signs of respiratory infections, 5 cases had varicella with the signs of respiratory infections and 2 cases were mumps with the signs of respiratory infections. Three hundred strains of potential (greater than or equal to 10(7) CFU/ml) pathogens were recovered from 293 of the 568 cases, which consisted of 124 strains of Haemophilus influenzae, 58 strains of Streptococcus pneumoniae, 45 strains of Staphylococcus aureus, 26 strains of Branhamella catarrhalis, 25 strains of Streptococcus pyogenes, 9 strains of Klebsiella pneumoniae and 13 strains of other species, not including non-fermentile gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter calcoaceticus. Staphylococcus aureus and other strains were documented simultaneously in 6 out of 7 cases in which multi-organisms were recovered. Many strains of Staphylococcus aureus were isolated from young patients throughout the year. On the other hand many strains of Branhamella catarrhalis were isolated from elderly patients in winter. The sensitivity of 45 antimicrobial agents of 231 of 300 strains was determined by sensitivity disks (EIKEN, Japan). No strain of the Haemophilus influenzae in this study was resistant to ampicillin. None of the Streptococcus pneumoniae and Streptococcus pyogenes was resistant to ampicillin or cefazolin. None of the Staphylococcus aureus was resistant to cloxacillin, cefazolin, gentamicin or ofloxacin. We conclude from the above results that antibiotic-resistant strains are found presumably only in a very few cases in primary care clinic.     

Pathogenesis of bacterial respiratory infection and new approach of the treatment

Causative agents of respiratory infections has been changed because of increase in number of aged people and compromised host and the rapid development of new chemotherapeutic agents. Especially Branhamella catarrhalis (B. catarrhalis), which is very unique and has become a common respiratory pathogen, since 1980, in my department. Attachment ability of B. catarrhalis to oropharyngeal cells coincided with the acute exacerbation of chronic respiratory infections by this bacterium and the same phenomenon in pneumococcal infections was also established. In the hospital for aged people, two major pathogens Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) are specially seen. In these patients, the two major ones were isolated from the oropharynx. Non-typable Haemophilus influenzae (H. influenzae) is also very important in Japan like USA. Recurrent infection with this pathogen occurred due to the change of OMPs during the time period of more than one month. Complement and some amount of ceftadizim were inactivated by destroyed neutrophils in vitro. This result may explain one of the cause of intractability of P. aeruginosa infection. Monoclonal antibody against P. aeruginosa showed effectiveness in P. aeruginosa pneumonia model in mice. Intraabdominal administration of fibronectin also was effective for staphylococcal pneumonia in rat. Oropharyngeal pathogens like S. aureus, S. pneumonia, B. catarrhalis, H. influenzae and P. aeruginosa were killed by 100-500 times diluted solution of 7% povidonjod solution. Moreover the frequency of recurrence of infection by these bacteria were decreased by gargling this solution 3-4 times/day.(ABSTRACT TRUNCATED AT 250 WORDS)     

Respiratory tract infections caused by Branhamella catarrhalis in outpatients with pneumoconiosis

To investigate the occurrence of Branhamella catarrhalis respiratory tract infections in 109 outpatients with pneumoconiosis, clinical and bacteriological studies were performed during a 4-year period from April 1984 to March 1988. B. catarrhalis was isolated in 26 patients; only three of these received continuous corticosteroid treatment. The incidence of B. catarrhalis respiratory tract infections increased gradually during the years 1984-1986, but decreased for the first time in 1987 compared with the previous year. There was a seasonal variation in isolations with a peak incidence during the winter, a pattern in contrast to Haemophilus influenzae. Almost all isolates produced beta-lactamase. B. catarrhalis found in mixed culture was usually in association with H. influenzae or Streptococcus pneumoniae. The isolation rates for B. catarrhalis in sputum of patients with pneumoconiosis followed those of H. influenzae and S. pneumoniae, and almost all strains were positive for beta-lactamase, so B. catarrhalis should be admitted that it is a primary pathogen.     

Current issues in the management of bacterial respiratory tract disease: the challenge of antibacterial resistance

The worldwide burden of respiratory tract disease is enormous. Resistance to penicillins, macrolides, and cephalosporins is now detected among the leading bacterial pathogens that cause respiratory tract infections (RTIs)-Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. The increasing role of atypical/intracellular pathogens (eg, Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila) in RTIs, as well as their increase in antibiotic resistance prevalence, continues to be of great concern. More recently introduced treatment options for RTIs include the newer respiratory fluoroquinolones, along with the macrolides and azalides. Although these agents demonstrate good activity against common respiratory pathogens, reduced susceptibility to these agents has been reported. The ketolides are recently developed antibacterial agents with targeted-spectrum activity against common respiratory tract pathogens, including atypical/intracellular pathogens, and a low potential for inducing resistance. These promising new drugs have shown in vitro and in vivo efficacy in the treatment of community-acquired RTIs, such as community-acquired pneumonia, acute exacerbations of chronic bronchitis, and acute bacterial maxillary sinusitis.     

Major bacteria of community-acquired respiratory tract infections in Turkey

To determine the bacterial etiology of lower respiratory tract infections (LRTIs) in Turkey, quantitative cultures of sputum were carried out. The major pathogens for LTRIs were found to be Haemophilus influenzae, followed by Streptococcus pneumoniae and Moraxella catarrhalis. Only 6.1% of the H. inlfuenzae and all strains of M. catarrhalis were beta-lactamase producers. An E-test showed that 31.2% of the S. pneumoniae strains had an intermediate resistance to penicillin, and the remaining strains were susceptible; no fully resistant strains were detected.     

Infections due to encapsulated bacteria, Salmonella, Shigella, and Campylobacter

Bacterial infections occur often in HIV-infected patients. Defects in both cell-mediated and humoral immunity are associated with an increased frequency of infections due to encapsulated and enteric bacteria. Pneumonia caused by Streptococcus pneumoniae, Haemophilus influenzae, and other pathogens may occur early in the course of AIDS and have typical clinical presentations. Bacteremia is extremely common, and patients frequently fail to develop protective elevations in specific antibodies following infection. Recurrences are noted in up to one third of patients, and suppressive antimicrobial therapy may be required. The frequency of salmonellosis is increased as much as 20-fold in AIDS patients and is associated with bacteremia in more than 40 per cent of cases. Salmonella, Shigella, and Campylobacter infections in HIV-infected individuals may precede an AIDS diagnosis, may fail to respond to appropriate therapy, or may recur after completion of treatment. Prevention of bacterial infections with antibiotics or immunotherapy, or both, is recommended for children with AIDS or ARC.     

A comparative study of antibacterial activity of ceftibuten, ceftazidime, cefuroxime and ampicillin against clinical isolates

Ceftibuten is an orally active third generation new cephalosporin. Its antibacterial activity in vitro was tested to many clinical isolates and was compared to the activity of ceftazidime, cefuroxime and ampicillin, by twofold serial dilution method in Müller-Hinton agar--detection of minimum inhibitory concentrations (MIC) and by the disc-diffusion method of Kirby-Bauer. The new cephalosporin demonstrated great activity against the different clinical important strains. Many resistant strains to ampicillin were high susceptible to ceftibuten. The majority of Gram-negative organisms, including Enterobacteriaceae, the respiratory pathogens M.(B.) catarrhalis and H. influenzae are highly susceptible to Ceftibuten, however Pseudomonas, Acinetobacter are resistant. The majority of methicillin-susceptible strains of Staphylococcus are resistant too. New cephallosporin was also active against S. pyogenes (Streptococcus gr. A) and penicillin-susceptible pneumococci, but was inactive against S. agalactiae (Streptococcus gr. B), S. pneumoniae penicillin-resistant strains and enterococci, similar to the other cephalosporins. The activity of ceftibuten was higher than that of ampicillin and cefuroxime against beta-lactamases positive strains of H. influenzae and M.(B) catarrhalis, also against tested strains of Enterobacteriaceae. The major priority of the new antibacterial agent over other cephalosporins and ampicillin is its stability to hydrolysis by the main broad-spectrum beta-lactamases producing E. coli and K. pneumoniae sp.     

Clinical manifestations, diagnosis and treatment of Haemophilus influenzae infection

Haemophilus influenzae is a small, nonmotile, non-spore-forming bacterium, and a strict parasite of humans found principally in the upper respiratory tract. The production of capsule is of major significance to clinicians since it is an important virulence factor. We described six antigenically distinct capsular types, designated a-f. Spread from one individual to another occurs by airborne droplets or by direct contagion with secretions. Haemophilus influenzae produces at least two factors that inhibit the ciliary activity of human epithelial cells in vitro. One of this has been shown to be lipopolysaccharide and the other factor is of low molecular weight, most likely a heat-stable glycopeptide. Type b strains are distinguished by the production of capsular polysaccharide composed of repeating units of ribosyl-ribitol phosphate, account for greater than 95 percent of systemic infections in children. Two contrasting patterns of Haemophilus influenzae disease can be identified. The first and the most serious in its consequences is invasive infection such as meningitis, septic arthritis, epiglottitis, and cellulitis in which bacteremia is a prominent feature; these infections are usually caused by type b strains and occur in young children. The second category includes less serious but numerically more common infections, that occur as a result of contiguous spread of Haemophilus influenzae within the respiratory tract; e.g. otitis media, sinusitis. These latter infections are usually, but not invariably, caused by unencapsulated strains. A provisional diagnosis of meningitis, epiglottitis, facial cellulitis, or septic arthritis will usually be prompted by the history and clinical findings. Confirmation requires microbiologic studies. Cultures of blood, CSF and other normally sterile fluids are diagnostic and therefore under the appropriate circumstances mandatory. Whenever feasible, specimens obtained for culture should also the gram-strained. Detection of capsular antigen in serum, CSF or concentrated urine using immunoelectrophoresis, latex agglutination or enzyme linked immunosorbent assay may be diagnosed and can be found in up to 90 percent of culture proved cases of meningitis. Without treatment, infection due to Haemophilus influenzae can be rapidly fatal, particularly by meningitis and epiglottitis. There is currently a trend to use certain parenteral third generation cephalosporins as initial therapy when lifethreatening Haemophilus influenzae infection is known or suspected in children beyond the neonatal period, commonly used agents included cefotaxime or ceftriaxone. Antibiotic therapy is only one facet of the management of the child with Haemophilus influenzae infection, and critical attention must also be given to supportive therapy. In the ambulatory setting, ampicillin or amoxicillin for 10 days is often satisfactory for the less severe Haemophilus influenzae infections. Cephalosporins are often chosen for treatment of adults, with pneumonia when Haemophilus influenzae is documented.     

Identification of strains on recurrent Haemophilus influenzae infections in patients with chronic respiratory tract infections]

Nontypable Haemophilus influenzae is one of the most important pathogenic bacteria in respiratory tract infections. H. influenzae is most frequently associated with recurrent infections in chronic respiratory tract infections (CRTIs). It is known that H. influenzae often reemerges after the antibiotic treatment has been stopped. We analyzed serotype, biotype, and the OMP patterns of H. influenzae isolates from sputum of CRTIs patients to determine whether an exacerbation is caused by an identical H. influenzae strain, or by a new H. influenzae strain. One hundred eighty nine strains of H. influenzae were obtained from 124 exacerbation from 24 patients. The first and second isolates were identical in 23 out of 33 exacerbations (< or = 15-days interval between each exacerbation) and also in 22 out of 34 exacerbations (15 < days but < or = 30-days interval between each exacerbation). This is called early recurrence. In contrast, the first and second isolates were different in 28 out of 34 exacerbations (> 30-days interval between each exacerbation). This is called late recurrence. These results suggest that early recurrence and late recurrence of recurrent H. influenzae infections occur in a different mechanism.     

Treatment of acute exacerbations of chronic bronchitis: antibiotic therapy

Acute exacerbation of chronic bronchitis (AECB) is a condition associated with increased morbidity and mortality. Bacterial infections are the most frequent cause of exacerbations. The most common bacterial etiologies include Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumonia. The diagnosis of AECB is often based on the clinical presentation, but microbiological assessment, including Gram stain and sputum culture should be done. Antibiotic therapy should be used in patients with the following characteristics: underlying lung disease, frequent exacerbations, and comorbid conditions. Penicillins, erythromycin, beta-lactamase inhibitors, and trimethoprim-sulfamethoxazole have been the preferred antibiotics. However, because of the increasing prevalence of resistance among respiratory pathogens, mainly the production of beta-lactamase by H. influenzae and M. catarrhalis, and the emergence of multidrug-resistant S. pneumonia, new generation macrolides and fluoroquinolones should be the first line of treatment in selected patients. These drugs have increased efficacy and safety.     

The role of beta-lactamase in mixed infections in mice in relation to treatment with ampicillin

Beta-lactamase-producing Staphylococcus aureus and Bacteroides fragilis in a localized mixed infection has been found to degrade the beta-lactam antibiotic at the focus of infection, thus protecting both the bacteria and pathogens susceptible to the antibiotic. To determine if beta-lactamase produced by Hemophilus influenzae and Branhamella catarrhalis have similar importance in mixed infections, a thread infection model in mice was used to evaluate the capacity of beta-lactamase produced by S. aureus, B. catarrhalis, or H. influenzae to hydrolyze ampicillin in a mixed infection with Streptococcus pneumoniae in mice. For both S. aureus and B. catarrhalis, the ampicillin concentrations at infection sites where beta-lactamase was produced were lower than at sites where beta-lactamase was not produced; however, this difference was not found when clavulanic acid was added to the ampicillin. In mixed infections with strains that did not produce beta-lactamase, ampicillin concentrations were similar with or without clavulanic acid. S. aureus was the best "protector" followed by B. catarrhalis. The beta-lactamase produced by H. influenzae failed to protect the S. pneumoniae. No bactericidal effect of clavulanic acid was found.     

Relapse of acute purulent otitis media: antibiotic sensitivities of nasopharyngeal pathogens

The present investigation was conducted to find out if a relapse of acute purulent otitis media is associated with a decreased sensitivity of nasopharyngeal pathogens to commonly used antimicrobial agents. All but one of 63 children with relapse included in this study yielded one or more of the classical middle ear pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catarrhalis, S. pyogenes) in their nasopharynx (NPH) secretions. S. pneumoniae was the predominating isolate from NPH (71% of the patients) as well as from middle ear effusion (53%). At a control visit 4 weeks after the start of antibiotic therapy, 91% were NPH carriers of potential pathogens and S. pneumoniae was still the most common isolate (53%). Beta-lactamase was produced by 55% of B. catarrhalis isolates from the NPH specimens on the first visit, but only by 33% of B. catarrhalis isolates on the control visit. Two NPH isolates of H. influenzae produced beta-lactamase. One isolate of S. pneumoniae (serotype 18) was intermediately sensitive to phenoxymethylpenicillin. Generally low MICs were found for erythromycin and cefaclor. H. influenzae isolates were generally sensitive to ampicillin in vitro, but only 1 isolate was fully sensitive to erythromycin. B. catarrhalis isolates were uniformly sensitive to doxycycline and trimethoprim/sulphamethoxazole. No tolerance to penicillin was demonstrated in S. pneumoniae and H. influenzae. The present data indicate that the relapse of acute otitis media is not associated with development of tolerance or resistance to therapeutic antimicrobials commonly used.     

PROTEKT 1999-2000: a multicentre study of the antimicrobial susceptibility of respiratory tract pathogens in Japan.

DESIGN: A six-centre study in Japan during the winter of 1999-2000 assessed the in vitro activity of >20 antimicrobial agents against the common respiratory pathogens Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, and Moraxella catarrhalis. The minimum inhibitory concentrations (MIC) of each antimicrobial was determined against these isolates using National Committee for Clinical Laboratory Standards (NCCLS) methodology. RESULTS: Among S. pneumoniae isolates, 44.5% were penicillin resistant. The macrolide resistance rate was 77.9% with 90.5% of penicillin-resistant strains also being macrolide resistant. Resistance mechanisms in macrolide-resistant isolates were identified as mef(A) or erm(B) in 42.5% and 52.5%, respectively. Of the fluoroquinolone-resistant isolates (1.3%), most were also penicillin and macrolide resistant. All strains were inhibited by telithromycin at 相似文献   

Haemophilus influenzae survival during complement-mediated attacks is promoted by Moraxella catarrhalis outer membrane vesicles

Moraxella catarrhalis causes respiratory tract infections in children and in adults with chronic obstructive pulmonary disease. It is often isolated as a copathogen with Haemophilus influenzae. The underlying mechanism for this cohabitation is unclear. Here, in clinical specimens from a patient with M. catarrhalis infection, we document that outer membrane vesicles (OMVs) carrying ubiquitous surface protein (Usp) A1 and UspA2 (hereafter, UspA1/A2) were secreted. Further analyses revealed that OMVs isolated in vitro also contained UspA1/A2, which mediate interactions with, among other proteins, the third component of the complement system (C3). OMVs from M. catarrhalis wild-type clinical strains bound to C3 and counteracted the complement cascade to a larger extent than did OMVs without UspA1/A2. In contrast, UspA1/A2-deficient OMVs were significantly weaker inhibitors of complement-dependent killing of H. influenzae. Thus, our results suggest that a novel strategy exists in which pathogens collaborate to conquer innate immunity and that the M. catarrhalis vaccine candidates UspA1/A2 play a major role in this interaction.     

A prospective study of infections in lung cancer patients admitted to the hospital

STUDY OBJECTIVES: To determine the type of infections occurring in hospitalized patients with lung cancer. DESIGN: Prospective cohort study. SETTING: Department of internal medicine in a cancer hospital. PATIENTS: All patients with lung cancer who were hospitalized for any cause and who acquired infections at the time of admission or during the hospital stay between January 1997 and February 2001. INTERVENTIONS: None. RESULTS: Two hundred seventy-five patients with lung cancer had 435 episodes of fever and/or microbiologically or otherwise documented infection. Two hundred eighteen patients (79.3%) presented with non-small cell lung carcinoma, while 49 patients (17.8%) had small cell lung cancer. The majority of the infections occurred in the tracheobronchial tree (56%). There were 38 episodes of bacteremia or fungemia, and the primary site of infection was identified in 18 cases (47%). Microbiologically documented infections accounted for 61% of the infectious episodes, and included a total of 312 microorganisms. The most frequent pathogens were Gram-negative bacteria (64%), followed by Gram-positive bacteria (25%) and fungi (8%). The predominant Gram-negative bacteria were Haemophilus influenzae and Moraxella catarrhalis. Staphylococcus aureus, Streptococcus pneumoniae, coagulase-negative staphylococci, and Enterococcus faecalis essentially represented the Gram-positive bacteria. No multiresistant bacteria were observed. Bacteria were susceptible to most of the antibiotics classically administered for their treatment. CONCLUSIONS: The predominant site of infection in patients with lung cancer is the tracheobronchial tree, with S pneumoniae, S aureus, H influenzae, Escherichia coli, Pseudomonas aeruginosa, and M catarrhalis as the principal pathogens.