Overcoming penicillin failures in the treatment of Group A streptococcal pharyngo-tonsillitis

The causes of penicillin failure in eradicating Group A beta-hemolytic streptococcal pharyngo-tonsillitis (GABHS PT) are described. These include the presence of beta-lactamase producing bacteria that "protect" Group A beta-hemolytic streptococci (GABHS) from penicillins; the absence of bacteria that interfere with the growth of GABHS; co-aggregation between GABHS and Moraxella catarrhalis; and the poor penetration of penicillin into the tonsillar tissues and the tonsillo-pharyngeal cells. The use of antimicrobials that can overcome and modulate these phenomena and achieve better cure of the infection is described.

Biomimetic Total Synthesis and Antimicrobial Evaluation of Anachelin H

The first biomimetic total synthesis of the iron chelator anachelin H isolated from the cyanobacterium Anabaena cylindrica is reported. A first generation approach delivered one enantiomeric series of the polyketide fragment. Comparison of the 1H NMR data suggested the relative configuration of this anachelin fragment. The relative and absolute configuration of anachelin H was then established by total synthesis. A second generation approach involved the enzymatic conversion of N,N-dimethyltyramine to the anachelin chromophore. It was demonstrated that the enzyme tyrosinase is activated by the product during this reaction, the anachelin chromophore can serve as a tyrosinase activator. Anachelin H was evaluated against a panel of eleven bacterial and fungal pathogens, and moderate antibiotic activity (32 microg/mL) against Moraxella catarrhalis was found.

Study of nasopharyngeal bacterial flora. Variations in nasopharyngeal bacterial flora in schoolchildren and adults when administered antimicrobial agents

Changes in nasopharyngeal bacterial flora in adults with acute upper respiratory tract infection on administration of antimicrobial agents were investigated, and how these changes contrasted with those in children. Many patients with acute sinusitis due to allergies, and patients with malignancy and diabetes mellitus were included in the investigation. The detection rates of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, the major bacteria of acute otitis media (AOM), were 22%, 10%, and 7% respectively, which were significantly lower than those for children. Gram stain examination of nasopharyngeal swab samples showed a significant relation between leukocyte infiltration and the detection amount of S. pneumoniae (P = 0.0086). A significant relation (P = 0.0134) was also observed when H. influenzae was simultaneously detected. No significant change in the three major AOM bacteria present in nasopharyngeal bacterial flora after administration of antimicrobial agents was observed. However, all S. pneumoniae and H. influenzae detected after antimicrobial agent administration had the beta-lactam-resistance gene. It was observed that a significant improvement in leukocyte infiltration occurred 6 to 10 days after antimicrobial agent administration. In contrast, a significant improvement in children was observed at 2 to 5 days. In the adult subjects, this improvement was probably due to spontaneous remission rather than the effect of the antimicrobial agents. Although investigation of the long-term administration of antimicrobial agents was also conducted, its benefits for the patients were not elucidated.

Serial sinus aspirate samples during high-dose, short-course levofloxacin treatment of acute maxillary sinusitis

This study assessed daily aspirate samples from an indwelling sinus catheter during high-dose, short-course levofloxacin (750 mg daily x 5 days) treatment of acute maxillary sinusitis. Pathogens were isolated from 4 of 18 recruited patients. Bacteriologic eradication occurred within 24 h for 3 patients and 72 h for the 4th.

Evaluation of susceptibility patterns and BRO beta-lactamase types among clinical isolates of Moraxella catarrhalis

The aims of this study were to detect BRO beta-lactamase types and to evaluate any correlation with the susceptibility patterns of 90 clinical isolates of Moraxella catarrhalis. The overall prevalences of the bro-1 and bro-2 genes were 78% and 12%, respectively. Penicillin G MICs for BRO-1+ isolates were significantly higher than those for BRO-2+ isolates. All the isolates were susceptible to amoxycillin-clavulanate, levofloxacin and cefixime. Resistance to clarithromycin, tetracycline and trimethoprim-sulphamethoxazole was 1.1%, 2.2% and 1.1%, respectively. One-step, length-based PCR was an efficient method to screen for BRO beta-lactamase genes.

Antibacterial activity of carbapenems against clinically isolated respiratory bacterial pathogens in Japan between 2005 and 2006

The current status of the susceptibility of the main respiratory bacterial pathogens was evaluated by analysing the antibacterial activity of 21 drugs, including four carbapenems, against five species of the pathogens isolated between January 2005 and January 2006. A total of 157 strains were studied. Carbapenems inhibited the growth of all of the tested strains of Moraxella catarrhalis, Streptococcus pneumoniae and methicillin-susceptible Staphylococcus aureus strains at concentrations that were below the breakpoints set by the Japanese Society of Chemotherapy (2 and 1mug/mL for pneumonia and chronic respiratory tract infection, respectively). However, the majority of methicillin-resistant Staphylococcus aureus strains were resistant to carbapenems. Meropenem, but not the other carbapenems, inhibited the growth of all of the tested strains of Haemophilus influenzae isolates, including beta-lactamase-non-producing ampicillin-resistant strains, at concentrations of <or=1 microg/mL. The MIC(50) and MIC(90) of meropenem, 0.25 and 4 microg/mL, against Pseudomonas aeruginosa were the lowest of the carbapenems. By comparing these results with our previous data, it was found that there was no increase in resistance to carbapenems in any of the species tested. Thus, it can be stated that carbapenems have retained their position as key drugs for severe respiratory tract infections.

Activity of garenoxacin, an investigational des-F(6)-quinolone, tested against pathogens from community-acquired respiratory tract infections, including those with elevated or resistant-level fluoroquinolone MIC values

Garenoxacin, a novel des-F(6)-quinolone, was tested against 40423 pathogenic isolates associated with community-acquired respiratory tract infections (CA-RTIs). The strains included Streptococcus pneumoniae (18887), Haemophilus influenzae (15555), and Moraxella catarrhalis (5981), each isolated from a significant infection monitored by the SENTRY Antimicrobial Surveillance Program (1999-2005; North America, Latin America, and Europe). All tests were performed by reference broth microdilution methods for garenoxacin and 19 comparison agents. The garenoxacin MIC(90) and percentage (%) of strains inhibited at < or =1 microg/mL (proposed susceptible breakpoint) were S. pneumoniae (0.06 microg/mL, >99.9% susceptible), H. influenzae (< or =0.03 microg/mL, >99.9%), and M. catarrhalis (< or =0.03 microg/mL, 100.0%). The garenoxacin potency versus the pneumococci was 16- to 32-fold greater than levofloxacin or ciprofloxacin and 2-fold superior to moxifloxacin (MIC(90), 0.12 microg/mL). Resistances to other classes of antimicrobials did not adversely influence garenoxacin MIC results. Ciprofloxacin- or levofloxacin-resistant (MIC, > or =4 microg/mL) S. pneumoniae had higher garenoxacin MIC(90) values (1 microg/mL), but 90.6% to 97.5% of strains remained susceptible. Strains of all 3 monitored pathogens with mutations in the quinolone resistance determining region (QRDR) had higher garenoxacin MIC results, with > or =3 to 4 QRDR mutations required to elevate garenoxacin MIC values to > or =2 microg/mL. In conclusion, garenoxacin possesses a potent activity against pneumococci, H. influenzae, and M. catarrhalis strains worldwide, at a level significantly greater than the available tested agents in the fluoroquinolone class (ciprofloxacin, levofloxacin, and moxifloxacin). Only 13 and 4 isolates (0.07% and 0.03%) of S. pneumoniae and H. influenzae, respectively, had a garenoxacin MIC at > or =2 microg/mL, thus, making this new "respiratory antipneumococcal" quinolone an attractive candidate for the therapy of contemporary CA-RTI (bronchitis, pneumonia, and sinusitis).

In vitro and in vivo antibacterial evaluation of DRF 8417, a new oxazolidinone

OBJECTIVES AND METHODS

DRF 8417, a novel oxazolidinone, has been evaluated against Gram-positive and fastidious Gram-negative bacteria. In vitro activity of DRF 8417 was determined by broth microdilution method and in vivo efficacy studies were carried out in different murine systemic infection models.

RESULTS

DRF 8417 exhibited potent activity against Gram-positive pathogens with MIC(50) and MIC(90) values ranging from 0.06 to 1 mg/L. MICs against Haemophilus influenzae and Moraxella catarrhalis were one to two dilutions lower than those of linezolid. The in vivo efficacy, by oral route, in different susceptible and resistant Gram-positive systemic bacterial infection models ranged from 2.0 to 2.9 mg/kg.

CONCLUSIONS

These studies displayed the excellent in vitro and in vivo activity of DRF 8417 against Gram-positive pathogens and lower MICs when compared with linezolid against H. influenzae and M. catarrhalis.

Sulfatide and its synthetic analogues recognition by Moraxella catarrhalis

Moraxella catarrhalis is one of the major pathogens of respiratory and middle ear infections. Attachment of this bacterium to the surface of human pharyngeal epithelial cells is the first step in the pathogenesis of infections. This study revealed that sulfatide might act as a binding molecule for the attachment of M. catarrhalis to human pharyngeal epithelial cells. Furthermore, six different synthetic sulfatides were found to inhibit the attachment of M. catarrhalis significantly at an optimum concentration of 10 microg/ml. Synthetic sulfatides may have the potential to be used as a therapy to prevent M. catarrhalis infections.

Resistance patterns of selected respiratory tract pathogens in Poland

This study presents the results of a survey of the in-vitro susceptibility to antimicrobial agents of major pathogens responsible for community-acquired respiratory tract infections in Poland during 2002-2004. The collection of 1184 bacterial isolates comprised 398 Streptococcus pneumoniae, 344 Haemophilus influenzae, 302 Streptococcus pyogenes and 140 Moraxella catarrhalis. Among the pneumococcal isolates, 16.8% were penicillin-non-susceptible (PNSP), of which 80.6% were identified as multidrug-resistant. Overall, 9.0% of H. influenzae isolates were beta-lactamase-positive, although this percentage increased noticeably in the third year of the study. Based on PCR results, 12.8% of H. influenzae isolates were identified as low-level beta-lactamase-negative, ampicillin-resistant (BLNAR), and one isolate as low-level beta-lactamase-positive, amoxycillin-clavulanic acid-resistant (BLPACR). Pulsed-field gel electrophoresis (PFGE) classified 45 H. influenzae isolates with altered penicillin-binding proteins into 15 PFGE types, including two predominant types (with four and six sub-types) containing 15 and ten isolates, respectively. Resistance to tetracycline, erythromycin and clindamycin was found in 20.9%, 8.9% and 4.6% of S. pyogenes isolates, respectively. The production of beta-lactamase characterised 91.4% of M. catarrhalis isolates. In summary, the overall occurrence of PNSP in Poland remains stable, although there was a noticeable increase in the proportion of fully-resistant isolates. A rising trend in the prevalence of beta-lactamase producers and low-level BLNAR isolates was observed among Polish isolates of H. influenzae.

Activity of faropenem against middle ear fluid pathogens from children with acute otitis media in Costa Rica and Israel

Faropenem was tested against 1,188 middle ear fluid pathogens from children in Israel and Costa Rica. Against Streptococcus pneumoniae and Haemophilus influenzae, faropenem was the most active beta-lactam, with activity that was similar to or greater than of the other oral antimicrobial classes studied. Faropenem was also active against Moraxella catarrhalis and Streptococcus pyogenes.

Efficacy and safety of 3-day azithromycin versus 5-day moxifloxacin for the treatment of acute bacterial exacerbations of chronic bronchitis

Antibiotic therapy is of clinical benefit in certain patients with acute exacerbations of chronic bronchitis (AECB). In this randomised, investigator-blinded, multicentre trial, azithromycin (500mg once a day (qd) for 3 days) was compared with moxifloxacin (400mg qd for 5 days) for the treatment of outpatients with AECB (forced expiratory volume in 1s (FEV(1)) >35%). Of 342 patients randomised to either treatment, 169 received azithromycin and 173 received moxifloxacin. The mean age in the azithromycin and moxifloxacin groups was 56.4 years and 55.5 years, respectively. In the intent-to-treat analysis, clinical success rates for azithromycin and moxifloxacin were comparable at Days 10-12 (90% versus 90%, respectively) and Days 22-26 (81% versus 82%, respectively). Among patients who were culture-positive at baseline for Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis or Haemophilus parainfluenzae, clinical efficacy for azithromycin versus moxifloxacin at Days 10-12 was 93% versus 84%, respectively, and at Days 22-26 it was 89% versus 73%, respectively. The incidence of at least one treatment-related adverse event (AE) in the azithromycin and moxifloxacin groups was 18.3% and 19.1%, respectively. The most common AEs were diarrhoea, nausea, abdominal pain and vaginitis. Most treatment-related AEs were of mild or moderate severity, with no serious treatment-related AEs. One subject in the moxifloxacin group discontinued treatment owing to a treatment-related AE (precordial pain and dry throat). Compliance with both regimens was >90%. Three-day azithromycin and 5-day moxifloxacin demonstrate comparable efficacy and safety for the treatment of AECB in outpatients.

Treatment of acute otitis media with probiotics in otitis-prone children-a double-blind, placebo-controlled randomised study

BACKGROUND & AIMS

To examine whether probiotics would reduce the occurrence or duration of acute otitis media (AOM), or the nasopharyngeal carriage of otitis pathogens in otitis-prone children.

METHODS

During this double-blind, placebo-controlled, randomised, 24-week intervention, 309 otitis-prone children (10 months-6 years) consumed either one probiotic capsule (Lactobacillus rhamnosus GG and LC705, Bifidobacterium breve 99 and Propionibacterium freudenreichii JS) (n=155) or placebo (n=154) daily. Clinical examinations were carried out and nasopharyngeal samples taken three times. Parents recorded the symptoms of upper respiratory infection (URI) in a diary.

RESULTS

Probiotic treatment did not reduce the occurrence (probiotic vs. placebo: 72% vs. 65%, OR=1.48, 95% CI 0.87-2.52, p=n.s.) or the recurrence ( three) of AOM episodes (18% vs. 17%, OR=1.04, 95% CI 0.55-1.96, p=n.s.). The median duration of AOM episodes was 5.6 (IQR 3.5-9.4) vs. 6.0 (IQR 4.0-10.5) days, respectively (p= n.s.). There was a tendency showing a reduction in the occurrence of recurrent (4 to 6) respiratory infections in the probiotic group (OR for 4 URIs: 0.56, 95%CI 0.31-0.99, p=0.046; OR for 6 URIs: 0.59, 95% CI 0.34 to 1.03, p=n.s.). Probiotics did not affect the carriage of Streptococcus pneumoniae or Haemophilus influenzae, but increased the prevalence of Moraxella catarrhalis (OR=1.79, 95% CI 1.06-3.00, p=0.028).

CONCLUSIONS

Probiotics did not prevent the occurrence of AOM or the nasopharyngeal carriage of otitis pathogens in otitis-prone children. A tendency showing a reduction in recurrent respiratory infections must be confirmed in further studies.

High-throughput amplification fragment length polymorphism (htAFLP) analysis identifies genetic lineage markers but not complement phenotype-specific markers in Moraxella catarrhalis

Comparative high-throughput amplified fragment length polymorphism (htAFLP) analysis was performed on a set of 25 complement-resistant and 23 complement-sensitive isolates of Moraxella catarrhalis in order to determine whether there were complement phenotype-specific markers within this species. The htAFLP analysis used 21 primer-pair combinations, generating 41 364 individual fragments and 2273 fragment length polymorphisms, with an average of 862 polymorphisms per isolate. Analysis of polymorphism data clearly indicated the presence of two phylogenetic lineages and 40 (2%) lineage-specific polymorphisms. However, despite the presence of 361 (16%) statistically significant complement phenotype-associated polymorphisms, no single marker was 100% complement phenotype-specific. Furthermore, no complement phenotype-specific marker was found within different phylogenetic lineages. These findings agree with previous results indicating that the complement resistance phenotype within M. catarrhalis is probably defined by multiple genes, although not all of these genes may be present within all M. catarrhalis isolates.

Pharmacokinetic/pharmacodynamic modeling of in vitro activity of azithromycin against four different bacterial strains

The bacterial time-kill curves of azithromycin against four bacterial strains (Streptococcus pneumoniae/penicillin-intermediate, S. pneumoniae/penicillin-sensitive, Haemophilus influenzae and Moraxella catarrhalis) were determined by in vitro infection models. Eighteen different pharmacokinetic/pharmacodynamic models were fitted to the time-kill data using non-linear regression and compared for best fit. A simple, widely used E(max) model was not sufficient to describe the pharmacodynamic effects for the four bacterial strains. Appropriate models that gave good curve fits included additional terms for saturation of the number of bacteria (N(max)), delay in the initial bacterial growth phase and/or the onset of anti-infective activity (1-exp(-zt)) as well as a Hill factor (h) that captures the steepness of the concentration-response profile. Azithromycin was highly effective against S. pneumoniae strains and M. catarrhalis while the efficacy against H. influenzae was poor. Applications of these pharmacokinetic/pharmacodynamic models will eventually provide a tool for rational antibiotic dosing regimen decisions.

Macrolide resistance rates in respiratory pathogens in Slovenia following reduced macrolide use

The aim of this study was to investigate the association between decreased use of macrolides and resistance of common respiratory pathogens in Slovenia from 1999 to 2004. Over a 6-year period the consumption of macrolides in Slovenia decreased by 21.3%, from 3.81 defined daily doses/1000 inhabitants per day (DID) to 3.0 DID. The use of short-acting, intermediate-acting and long-acting subclasses of macrolides decreased by 50%, 18% and 13%, respectively. In the same period, resistance of invasive strains of Streptococcus pneumoniae increased from 4.6% to 11.1% and resistance of non-invasive strains of S. pneumoniae and Streptococcus pyogenes increased from 12.8% to 20.2% and from 7.4% to 12.5%, respectively. Resistance increased significantly more in children than in adults (P=0.05) and was significantly correlated with increased use of intermediate-acting macrolides (r=0.94 for non-invasive S. pneumoniae and r=0.96 for S. pyogenes) in children. Resistance of Haemophilus influenzae and Moraxella catarrhalis was low and did not change. In children and adults, the emergence and spread of multidrug-resistant strains of invasive S. pneumoniae was observed. The decline in total macrolide use was not paralleled by reduced macrolide resistance rates of S. pyogenes and S. pneumoniae during the 6-year period. There was a strong correlation between the use of intermediate-acting macrolides and macrolide resistance of S. pyogenes and S. pneumoniae in children. Further reduction in the use of intermediate- and long-acting macrolides should be encouraged.

Outpatient antibiotic therapy as a predisposing factor for bacterial resistance: a rational approach to airway infections

OBJECTIVES

To present evidence-based recommendations for the use of antibiotics for the treatment of the most common acute respiratory infections (ARI) and the available information on the importance of this type of management.

SOURCES

MEDLINE and LILACS databases, technical publications by international organizations, national and international directives. The search terms acute respiratory infection, otitis, sinusitis, tonsillitis, pneumonia, antibiotic, guidelines and bacterial resistance were used. Articles cited by the articles selected were analyzed for information of interest.

SUMMARY OF THE FINDINGS

Bacterial resistance has grown, to the extent that today it is recognized as a global public health problem. ARI are the most common cause of antibiotic usage within the community; yet a large proportion of these cases, compromising the upper (otitis, sinusitis, tonsillitis) or the lower airways (pneumonia), are the result of viral infections. Recommendations to rationalize the use of antibiotics in patients with ARI have the common objective of minimizing unnecessary antibiotic use, since "antibiotic pressure" is one of the factors triggering bacterial resistance.

CONCLUSIONS

It is of great importance to differentiate among ARI patients those who will benefit from the use of antibiotics. The establishment of recommendations for the prescription of antibiotics is one strategy for minimizing the frequency of bacterial resistance.

Discrepancy between antibiotics administered in acute exacerbations of chronic bronchitis and susceptibility of isolated pathogens in respiratory samples: multicentre study in the primary care setting

A national multicentre prevalence study was undertaken to determine the bacterial strains associated with mild-to-moderate acute exacerbations of chronic bronchitis (AECB) in the primary care setting and the susceptibility of isolated pathogens to different antimicrobials usually prescribed to these patients. All samples were processed by a central reference laboratory. Microdilution tests were carried out to establish the minimum inhibitory concentration (MIC) of various antimicrobials. A double-disk test was performed to establish the macrolide resistance phenotype in Streptococcus pneumoniae. Tests to detect the presence of beta-lactamase in Haemophilus influenzae and Moraxella catarrhalis and polymerase chain reaction to detect the presence of ermB and mefA genes in S. pneumoniae isolates were also performed. A total of 1537 patients were included in the trial and 468 microorganisms were isolated from sputum samples, with the most frequent isolates being S. pneumoniae (34.8%), M. catarrhalis (23.9%) and H. influenzae (12.6%). Resistance rates of pneumococci were 47.2% for penicillin, 1.2% for amoxicillin, 34.3% for macrolides (87.5% of which showed high-level resistance), 13.6% for cefuroxime/axetil and 4.2% for levofloxacin. No bacterial isolates showed resistance to telithromycin. Empirical antibiotic treatment was prescribed to 98.3% of patients, including macrolides to 36.6%, amoxicillin with or without clavulanic acid to 32.3% and fluoroquinolones to 16.1%. In conclusion, S. pneumoniae was the most frequently isolated bacteria in patients with mild-to-moderate AECB. Despite the high rates of resistance of pneumococci to macrolides, they continue to be the most widely used antibiotics in primary care to treat AECB.

Selection of retapamulin, a novel pleuromutilin for topical use

The in vitro activity of retapamulin was determined and compared to that of topical and community antibiotics. The MIC(90)s of retapamulin against Staphylococcus aureus and Streptococcus pyogenes were 0.12 microg/ml and 0.016 microg/ml, respectively. Retapamulin has a low propensity to select resistance and produces an in vitro postantibiotic effect.

[Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (2004)]

From October 2004 to September 2005, we collected the specimen from 319 patients with lower respiratory tract infections in 12 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various antibacterial agents and patients' characteristics. Of 383 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in inflammation, 381 strains were examined. The breakdown of the isolated bacteria were: Staphylococcus aureus 87, Streptococcus pneumoniae 80, Haemophilus influenzae 78, Pseudomonas aeruginosa (non-mucoid) 35, P. aeruginosa (mucoid) 9, Klebsiella pneumoniae 15, Moraxella subgenus Branhamella catarrhalis 30, etc. Of 87 S. aureus strains, those with 2 microg/mL or less of MIC of oxacillin (methicillin-sensitive S. aureus: MSSA) and those with 4 microg/mL or more of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) were 40 (46.0%) and 47 (54.0%) strains, respectively. Against MSSA, imipenem had the most potent antibacterial activity and inhibited the growth of all the strains at 0.063 microg/mL. Against MRSA, vancomycin showed the most potent activity and inhibited the growth of all the strains at 1 microg/mL. Arbekacin (ABK) also showed the potent activity and its MIC90 was 2 microg/mL. Carbapenems showed the most potent activities against S. pneumoniae and inhibited the growth of all the strains at 0.25-0.5 microg/mL. Cefozopran (CZOP) also had a preferable activity (MIC90: 1 microg/mL) and inhibited the growth of all the strains at 2 microg/mL. In contrast, there were high-resistant strains (MIC: 128 microg/mL or more) for ABK (2.5%), erythromycin (37.5%), and clindamycin (38.8%). Against H. influenzae, levofloxacin showed the most potent activity and inhibited the growth of all the strains at 0.125 microg/mL. Meropenem showed the most potent activity against P. aeruginosa (mucoid) and inhibited the growth of all the strains at 2 microg/mL. Against P. aeruginosa (non-mucoid), amikacin (AMK) had the most potent activity and its MIC90 was 4 microg/mL. The activity of CZOP against the non-mucoid type also was preferable and its MIC90 was 8 microg/mL. Against K. pneumoniae, CZOP, cefmenoxime, cefpirome, flomoxef were the most potent activity and inhibited the growth of all the strains at 0.063 microg/mL. Also, all the agents generally showed a potent activity against M. (B.) catarrhalis and the MIC90 of them were 4 microg/mL or less. The approximately half the number (57.0%) of the patients with respiratory infection were aged 70 years or older. Bacterial pneumonia and chronic bronchitis accounted for 50.8% and 23.8% of all the respiratory infection, respectively. The bacteria frequently isolated from the patients with bacterial pneumonia were S. aureus (21.6%), S. pneumoniae (24.7%) and H. influenzae (20.1%). S. aureus (20.9%), S. pneumoniae (16.1%), and H. influenzae (16.1%) also were relatively frequently isolated from the patients with chronic bronchitis. Before the drug administration, the bacteria frequently isolated from the patients were S. pneumoniae (22.3%) and H. influenzae (25.1%). The bacteria relatively frequently isolated from the patients treated with macrolides were P. aeruginosa and the isolation frequency was 43.5%.

Antibacterial activity of propolis and its active principles alone and in combination with macrolides, beta-lactams and fluoroquinolones against microorganisms responsible for respiratory infections

Propolis is produced by bees and is reported to have several pharmaceutical properties. Its antibacterial activity against strains causing upper respiratory tract infections is particularly important: propolis might be used as a therapeutic agent to prevent the bacterial infections that sometimes overlap viral infections. In this study the in vitro activity of both an alcoholic solution and a hydroglyceric extract of propolis, as well as its active principles, was tested against bacteria responsible for respiratory infections (Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis and Streptococcus pyogenes). We also evaluated the in vitro activity of a combination of propolis and its active principles and some beta-lactams, macrolides and fluoroquinolones. Our results, though not demonstrating a clearly synergistic activity between antibiotics and propolis and its constituents, show the possibility of using natural preparations, due to their antimicrobial and anti-inflammatory properties, to enhance antibacterial therapy.

Antibacterial activity of tosufloxacin against major organisms detected from patients with respiratory or otorhinological infections: comparison with the results obtained from organisms isolated about 10 years ago

The minimum inhibitory concentrations (MICs) of tosufloxacin and other fluoroquinolone antimicrobials for Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella (Branhamella) catarrhalis, isolated, between January 2003 and July 2004, from patients suspected of having respiratory or otorhinological infections were determined. The results were compared with those for these organisms isolated in 1994, plus some H. influenzae strains isolated in 1998. Tosufloxacin was the most potent of all the antibiotics tested for antibacterial activity against S. pneumoniae (including penicillin-intermediate S. pneumoniae and penicillin-resistant S. pneumoniae). The MIC50 and MIC90 values did not differ from those obtained for the strains isolated in 1994. Fluoroquinolones exerted the most potent antibacterial activity against M. (B.) catarrhalis; the MICs for most of the strains were < or = 0.06 microg/ml; fluoroquinolones inhibited the growth of all the strains at 0.25 microg/ml or less. Fluoroquinolones showed the most potent antibacterial activity against H. influenzae strains isolated between 2003 and 2004, and in 1994, but, for one H. influenzae strain isolated, between 2003 and 2004, the MICs of fluoroquinolones were high. Some strains of S. pneumoniae and H. influenzae were resistant to fluoroquinolones. Genetic analysis showed that all of these strains had mutations in the quinolone resistance-determining region, but there were no differences according to the years of isolation. These results indicate that tosufloxacin has potent antibacterial activity against major organisms isolated from patients with respiratory or otorhinological infections; further, the results of the present study did not differ from those obtained about 10 years ago.

In vitro activity of cefditoren: antimicrobial efficacy against major respiratory pathogens from Asian countries

In this study we evaluated the in vitro activities of cefditoren and 14 other comparator agents against 1025 isolates of major respiratory tract pathogens including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Klebsiella pneumoniae and Staphylococcus aureus. Bacterial isolates were collected from 11 Asian countries. The majority of S. pneumoniae isolates (98.8%) were susceptible to cefditoren. The MIC(50) and MIC(90) values (minimum inhibitory concentrations for 50% and 90% of the organisms, respectively) of S. pneumoniae were <or=0.06 microg/mL and 1 microg/mL, respectively. These values were 2-32-fold lower than those of the other cephalosporins. Activity against S. pneumoniae was observed irrespective of penicillin or macrolide resistance. Cefditoren was also active against methicillin-susceptible S. aureus (100% susceptible; MIC(90)=1 microg/mL), H. influenzae (100% susceptible; MIC(90)<or=0.016 microg/mL) and M. catarrhalis (MIC(90)=0.016 microg/mL). However, the cefditoren MIC(90) of K. pneumoniae reached only 64 microg/mL (81.4% susceptible), which may be due to the high incidence of extended-spectrum beta-lactamases in Asian countries. Therefore, cefditoren should be considered as a therapeutic option for the treatment of respiratory tract infections in Asian countries.

Activities of ceftobiprole, a novel broad-spectrum cephalosporin, against Haemophilus influenzae and Moraxella catarrhalis

Ceftobiprole, a broad-spectrum pyrrolidinone-3-ylidenemethyl cephem currently in phase III clinical trials, had MICs between 0.008 microg/ml and 8.0 microg/ml for 321 clinical isolates of Haemophilus influenzae and between < or =0.004 microg/ml and 1.0 microg/ml for 49 clinical isolates of Moraxella catarrhalis. Ceftobiprole MIC(50) and MIC(90) values for H. influenzae were 0.06 microg/ml and 0.25 microg/ml for beta-lactamase-positive strains (n = 262), 0.03 microg/ml and 0.25 microg/ml for beta-lactamase-negative strains (n = 40), and 0.5 microg/ml and 2.0 microg/ml for beta-lactamase-negative ampicillin-resistant strains (n = 19), respectively. Ceftobiprole MIC(50) and MIC(90) values for beta-lactamase-positive M. catarrhalis strains (n = 40) were 0.12 microg/ml and 0.5 microg/ml, respectively, whereas the ceftobiprole MIC range for beta-lactamase-negative M. catarrhalis strains (n = 9) was < or =0.004 to 0.03 microg/ml. Ceftriaxone MICs usually were generally at least twofold lower than those of ceftobiprole, whereas amoxicillin-clavulanate MICs usually were higher than those of ceftobiprole. Azithromycin and telithromycin had unimodal MIC distributions against H. influenzae, with MIC(90) values of azithromycin and telithromycin of 2 microg/ml and 4 microg/ml, respectively. Except for selected quinolone-nonsusceptible H. influenzae strains, moxifloxacin proved highly active, with MIC(90) values of 0.12 microg/ml. Time-kill analyses showed that ceftobiprole, ceftriaxone, cefpodoxime, amoxicillin-clavulanate, azithromycin, telithromycin, and moxifloxacin were bactericidal at 2x MIC by 24 h against all 10 H. influenzae strains surveyed. Only modest increases in MICs were found for H. influenzae or M. catarrhalis clones after 50 serial passages in the presence of subinhibitory concentrations of ceftobiprole, and single-passage selection showed that the selection frequency of H. influenzae or M. catarrhalis clones with elevated ceftobiprole MICs is quite low.