Bactericidal activity of topical antiseptics and their gargles against Bordetella pertussis.

Bordetella pertussis is the etiological agent of whooping cough, a common cause of respiratory illness in both children and adults. In the present study, we investigated the bactericidal activity of four antiseptics-povidone-iodine (PVP-I), benzethonium chloride (BEC), chlorhexidine gluconate (CHG) and benzalkonium chloride (BAC)-against B. pertussis ATCC9797 and clinical isolates. Among the topical antiseptics, PVP-I, BEC, and BAC, PVP-I and BAC in particular, showed high bactericidal activity, whereas CHG had low activity. PVP-I gargle also showed high bactericidal activity, similar to topical PVP-I. However, BEC gargle had low bactericidal activity. Our results indicate that topical PVP-I and BAC, and PVP-I gargle would be useful as effective antiseptics against B. pertussis.

Treatment of Pseudomonas aeruginosa biofilms with a combination of fluoroquinolones and fosfomycin in a rat urinary tract infection model.

Foreign body-associated infectious disease is currently one of the most problematic hospital-acquired infections. Patients with placement of urinary catheters are especially susceptible to such infection, that is biofilm infection. In this study, we focused on the therapeutic efficacy of prulifloxacin (PUFX) against Pseudomonas aeruginosa OP 14-210, isolated from a patient with complicated urinary tract infection. This microbe formed a biofilm on the surface of a polyethylene tube (PT) placed in a rat bladder without surgical manipulation. In addition, we attempted to eradicate the biofilm by treatment with a combination of PUFX and fosfomycin (FOM). A single oral administration of PUFX at a dose of 20 mg/kg was effective against P. aeruginosa as a biofilm, yielding a significant reduction in CFU per PT of approximately 1 log(10) CFU/PT compared with that in untreated controls. A similar therapeutic effect was also observed in levofloxacin-treated rats, and albeit slightly weaker, in ciprofloxacin-treated animals as well. Because 3 days' consecutive treatment with each fluoroquinolone did not further decrease the viable cell counts on the PT, we tested the efficacy of combining PUFX and FOM. These two drugs, administered once a day for 3 days, at doses of 20 and 100 mg/kg, respectively, resulted in significant decreases of viable cell counts on the PT of more than 1.5 log(10) CFU/PT compared with PUFX alone (P < 0.05). As seen by scanning electron microscopy, destruction and disappearance of multilayer biofilms occurred after treatment with this drug combination. Such combination therapy with PUFX and FOM may be advantageous for treating biofilm-related infectious diseases.

In vitro activities of oral cephem and telithromycin against clinical isolates of major respiratory pathogens in Japan.

The in vitro antibacterial activities of oral cephem antibiotics and ketolide telithromycin against major respiratory pathogens possessing beta-lactam-resistant mutations (within the pbp gene) and/or macrolide-resistant genes (erm and mef) were examined in clinical isolates collected at 66 institutes in all over the Japan between 2002 and 2003. Telithromycin showed the strongest antibacterial activity against methicillinsusceptible Staphylococcus aureus strains with and without macrolide-resistant genes, such as ermA or ermC gene. All the cephem antibiotics showed potent antibacterial activity against Streptococcus pyogenes, with minimum inhibitory concentrations (MICs) of 0.015 mg/L or lower. Cefdinir had a much higher MIC90 against genotypic penicillin-resistant Streptococcus pneumoniae (gPRSP) than cefditoren and cefcapene (8 mg/L cefdinir vs. 1 mg/L cefditoren and cefcapene). The majority of gPRSP harbored either ermB or mefA, and the antibacterial activity of telithromycin against these strains was decreased however some susceptibility was still sustained. Cefditoren exerted the strongest antibacterial activity against beta-lactamase-negative ampicillin-resistant Haemophilus influenzae, with an MIC90 of 0.5 mg/L. These results underline the importance of checking the susceptibility and selecting an appropriate antibiotic against target pathogens.

Synergistic effect of fosfomycin and fluoroquinolones against Pseudomonas aeruginosa growing in a biofilm.

Ulifloxacin is the active form of the prodrug prulifloxacin and shows a highly potent antipseudomonal activity. In this study, we examined the combined effect of fosfomycin and ulifloxacin against Pseudomonas aeruginosa (P. aeruginosa) growing in a biofilm using a modified Robbins device with artificial urine, and compared it to that of the combination of fosfomycin and ciprofloxacin or levofloxacin. An ATP bioluminescence assay was used to evaluate the antibacterial activity of the agents against sessile cells in a mature biofilm developed on a silicon disk. The total bioactivity of P. aeruginosa growing in a biofilm that had not been fully eradicated by fosfomycin or any of the fluoroquinolones alone at 10 times the MIC decreased after combination treatment with fosfomycin and fluoroquinolones. Morphological changes occurred in a time-dependent fashion; namely, swollen and/or rounding cells emerged within a couple of hours after combination treatment, marking the initial stage in the process leading to the destruction of the biofilms. We could not find any difference among the 3 fluoroquinolones with regard to their synergistic effects when administered with fosfomycin. The combination treatment of fosfomycin and fluoroquinolones with highly potent antipseudomonal activities was effective in eradicating sessile cells of P. aeruginosa in the biofilm and promises to be beneficial against biofilm-associated infectious diseases.

Cell profiles of bronchoalveolar lavage fluid as prognosticators of idiopathic pulmonary fibrosis/usual interstitial pneumonia among Japanese Patients.

BACKGROUND: The role of bronchoalveolar lavage fluid (BALF) cell profiles in predicting the clinical outcome of idiopathic pulmonary fibrosis (IPF)/usual interstitial pneumonia (UIP) is still under discussion. OBJECTIVE: To determine whether BALF cell profiles affect the survival of patients with UIP diagnosed by surgical lung biopsy/autopsy at the early stage of IPF. METHODS: This hospital-based retrospective cohort study used 81 Japanese patients with histologically proven IPF/UIP who underwent BAL examination. The BALF samples were obtained from non-current smokers: NCS (n = 41) and current smokers: CS (n = 40). The Kaplan-Meier and Cox's proportional hazard methods were used to estimate the survival and evaluate the risk ratio for death in the two groups. To detect the multicollinearity, a stepwise regression was employed. RESULTS: A slight increase in the absolute numbers of BALF neutrophils tended to relate to a decrease in the relative risk for death in NCS patients and CS patients in the univariate analysis. In stepwise regression, the increase in percent vital capacity and the increase in the BALF CD4/CD8 ratio in NCS was detected as a favorable predictor, while increased BALF cells affected the results due to chronic smoking in CS. CONCLUSIONS: Based on the study bias of the biopsy-proven IPF/UIP patients at stable stages, an independent variable indicating a favorable outcome was an increased BALF CD4/CD8 ratio in NCS patients, while it was difficult to identify definite prognosticators in CS patients.

Patient characteristics and clinical features of Japanese sarcoidosis patients with low bronchoalveolar lavage CD4/CD8 ratios.

BACKGROUND: Previous studies have shown that there is an association between low BALF (bronchoalveolar lavage fluid) CD4/CD8 ratio and lower remission rates in sarcoidosis patients. AIM: To investigate the patient characteristics and clinical features of Japanese sarcoidosis patients with low BALF CD4/CD8 ratios. METHODS: 322 Japanese sarcoidosis patients were retrospectively analyzed, and 3 groups were selected according to BALF CD4/CD8 ratios as follows: patients with the BALF CD4/CD8 ratio in the lowest 5 percentile (Group 1: 0.43-1.41), median 5 percentile (Group II: 4.68-5.47), and top 5 percentile (Group III: 12.6-60.1). Each group consisted of 16 patients (5% of 322 patients). The patient characteristics, clinical features, and the short-term prognosis for at least 2 years (average 116 months) were compared among the groups. Multivariate analysis was performed for 322 patients to investigate the determinants of BALF CD4/CD8 ratios. RESULTS: The number of BALF CD8+ cells were greater in Group I than in the other two groups. In Group I, there were higher incidences of younger age, male gender, and lower number of extrathoracic lesions compared with Group III. Multivariate analysis showed that younger age and male gender were independently associated with low BALF CD4/CD8 ratios. The frequency of treatment with corticosteroid and progression to pulmonary fibrosis tended to be higher in Group I. CONCLUSIONS: Low BALF CD4/CD8 ratios were due to increased number of BALF CD8+ cells. Younger age and male gender were independently associated with low BALF CD4/CD8 ratios in sarcoidosis patients.

[Antimicrobial activity of fosfomycin under various conditions against standard strains, beta-lactam resistant strains, and multidrug efflux system mutants].

The purpose of this study was to evaluate the possible benefit of fosfomycin (FOM) as prophylactic antibiotic in terms of antimicrobial activity and the potential of inducibility of beta-lactamase, compared with cefazolin, cefotiam, cefmetazole, and piperacillin that are commonly used as perioperative agents. The in vitro activity of FOM against aerobic Gram-negative bacteria using Mueller-Hinton agar or nutrient agar supplemented with glucose-6-phosphate (G6P) as tested medium increased within a range from 2 to 256 times the activity in the medium without G6P. However, the susceptibility of Gram-positive bacteria to FOM remained largely unchanged with or without G6P. There was no aerobic- or anaerobic-bacteria which changed susceptibility against beta-lactam antibiotics under various tested medium conditions. FOM demonstrated strong bactericidal activity against Escherichia coli and Pseudomonas aeruginosa in a dose dependent manner, and decreased viable cell counts of Staphylococcus aureus. In the case of P. aeruginosa, transmission electron micrographs study revealed that numerous lysed cells were present 2 hours after treatment with FOM at four times the MIC. First and second generation cephalosporins induced AmpC-type beta-lactamase in a dose dependent manner among beta-lactamase inducible strains of P. aeruginosa and Enterobacter cloacae. On the other hand, inducible activity of FOM on beta-lactamase production was less than 1/25 to 1/65 compared with those of cephalosporins. In addition, FOM maintained strong antimicrobial activity for over then 20 years after marketing, because of the excellent stability against various types of beta-lactamase produced by plasmid-carrying bacteria and clinical isolates. FOM was not extruded by four types of efflux systems, such as MexAB-OprM, MexCD-OprJ, MexXY/ OprM and MexEF-OprN, however beta-lactam antibiotics were substrates of MexAB-OprM and MexCD-OprJ. In conclusion, FOM provides adequate coverage for both aerobic Gram-positive and Gram-negative bacteria causing postoperative infections. Further, FOM would not select/concentrate beta-lactamase producing bacteria in the clinical fields and would not be a substrate for multidrug efflux system of P. aeruginosa.

Differential effects of fosfomycin and corticosteroid on the molar ratio of interleukin-1 receptor antagonist/interleukin-1beta in the culture supernatants of mononuclear phagocytes from patients with sarcoidosis.

We compared the effects of fosfomycin, an antibiotic reported to possess immunomodulatory activities, and prednisolone on the production of interleukin-1 receptor antagonist (IL-1ra) and IL-1beta by bronchoalveolar lavage fluid (BALF) macrophages obtained from sarcoidosis patients. The molar IL-1ra/IL-1beta ratio in the culture supernatants of BALF macrophages obtained from sarcoidosis patients, which was lower in sarcoidosis patients than in healthy nonsmokers, was significantly increased in the presence of fosfomycin, but decreased by prednisolone. Further, the molar IL-1ra/IL-1beta ratios in the culture supernatants of peripheral blood mononuclear cells isolated from four of five patients after fosfomycin administration for 14 days were higher than the ratios measured before fosfomycin administration. Fosfomycin showed an anti-inflammatory effect in a different way, when compared with that of prednisolone.