Acute bronchopulmonary infection due to Streptococcus milleri in a child with cystic fibrosis. (1/414)

An 8 year old girl with cystic fibrosis had severe respiratory disease associated with chronic Pseudomonas aeruginosa bronchopulmonary infection. Despite regular courses of intravenous antipseudomonal antibiotics, she continued to deteriorate over 18 months with persistent productive cough, worsening respiratory function, and increasing oxygen dependence. During her 11th admission Streptococcus milleri was isolated from sputum cultures in addition to P aeruginosa. She failed to respond to antipseudomonal antibiotics but improved dramatically with the addition of intravenous benzylpenicillin. Although S milleri is considered a normal mouth commensal and its isolation from sputum of cystic fibrosis patients is of uncertain significance, it was associated with clinically significant infection in this child. S milleri was eradicated with antibiotic treatment and clinical improvement has been maintained.  (+info)

Intravenous colistin as therapy for nosocomial infections caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii. (2/414)

Sixty nosocomial infections caused by Pseudomonas aeruginosa and Acinetobacter baumannii resistant to aminoglycosides, cephalosporins, quinolones, penicillins, monobactams, and imipenem were treated with colistin (one patient had two infections that are included as two different cases). The infections were pneumonia (33% of patients), urinary tract infection (20%), primary bloodstream infection (15%), central nervous system infection (8%), peritonitis (7%), catheter-related infection (7%), and otitis media (2%). A good outcome occurred for 35 patients (58%), and three patients died within the first 48 hours of treatment. The poorest results were observed in cases of pneumonia: only five (25%) of 20 had a good outcome. A good outcome occurred for four of five patients with central nervous system infections, although no intrathecal treatment was given. The main adverse effect of treatment was renal failure; 27% of patients with initially normal renal function had renal failure, and renal function worsened in 58% of patients with abnormal baseline creatinine levels. Colistin may be a good therapeutic option for the treatment of severe infections caused by multidrug-resistant P. aeruginosa and A. baumannii.  (+info)

Comparison of selective broth medium plus neomycin-nalidixic acid agar and selective broth medium plus Columbia colistin-nalidixic acid agar for detection of group B streptococcal colonization in women. (3/414)

The combination of neomycin-nalidixic acid (NNA) agar and a selective broth medium (SBM) has recently been shown to improve the sensitivity of screening cultures for group B streptococcal (GBS) carriage in women. Because of the relatively high cost of NNA agar, a study was initiated to determine whether Columbia colistin-nalidixic acid (CNA) agar would be an equally sensitive, more economical alternative. A total of 580 cervical-vaginal and/or rectal specimens submitted for detection of GBS were included in the study. Each was plated onto NNA and CNA agar and then inoculated into SBM. GBS were recovered from 95 of 580 (16.4%) specimens, including 61 isolates from CNA, 74 from NNA, 73 from the CNA-SMB combination, and 86 from the NNA-SMB tandem. Of those, 22 isolates were recovered on NNA but not CNA, 9 were cultured on CNA but not NNA, 52 were isolated on both media, and 12 were recovered from subcultures of SBM only. The overall sensitivity of CNA alone (64. 2%) was statistically significantly less than that of NNA agar (77. 9%), as was the sensitivity of combination of CNA plus SBM (76.8%) compared to that of NNA plus SBM (90.5%). Based on these findings, CNA should not be considered an acceptable alternative to NNA for the detection of GBS colonization in women despite potential cost savings.  (+info)

In vitro activities of membrane-active peptides alone and in combination with clinically used antimicrobial agents against Stenotrophomonas maltophilia. (4/414)

The in vitro activities of buforin II, cecropin P1, and magainin II, alone and in combination with six clinically used antimicrobial agents, against 12 clinical isolates of Stenotrophomonas maltophilia were investigated. Antimicrobial activities were measured by MIC and time-kill studies. The isolates were susceptible to the peptides at concentrations in the range of 0.50 to 16 microg/ml. Synergy was observed when the peptides were combined with polymyxin E, meropenem, ceftazidime, piperacillin, and clarithromycin.  (+info)

Comparison of isolation of Haemophilus vaginalis (Corynebacterium vaginale) from peptone-starch-dextrose agar and Columbia colistin-nalidoxic acid agar. (5/414)

A total of 447 cervical or vaginal specimens were inoculated in parallel onto peptone-starch-dextrose (PSD) and Columbia colistin (10 mg/ml)-nalidixic acid (15 mug/ml) (CNA) agar and were incubated for 48 h at 35 degrees C in an atmosphere with 2 to 10% CO2. One hundred (22.4%) of the cultures were positive for Haemophilus vaginalis. Forty-eight of the isolates were recovered from both PSD and Columbia CNA agar, five from PSD only, and 47 from Columbia CNA agar only (P less than 0.001). On Columbia CNA agar, 76 of the isolates were detected after 24 h of incubation, and the remainder were detected within 4 days of incubation.  (+info)

Contemporary assessment of antimicrobial susceptibility testing methods for polymyxin B and colistin: review of available interpretative criteria and quality control guidelines. (6/414)

The emergence of infections caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter spp. has necessitated the search for alternative parenteral agents such as the polymyxins. The National Committee for Clinical Laboratory Standards (NCCLS) documents do not currently provide interpretative criteria for the testing of the polymyxins, colistin and polymyxin B. Therefore, an evaluation of the antimicrobial activity of colistin and polymyxin B was initiated using 200 bloodstream infection pathogens collected through the SENTRY Antimicrobial Surveillance Program. All susceptibility tests were performed according to the NCCLS recommendations. Polymyxin B and colistin displayed a nearly identical spectrum of activity, exhibiting excellent potency against P. aeruginosa (MIC(90), 2 microg/ml) and Acinetobacter sp. (MIC(90), 2 microg/ml). In contrast, they showed limited activity against some other nonfermentative bacilli such as Burkholderia cepacia (MIC(90), >/=128 microg/ml). Excellent correlation was achieved between broth microdilution and agar dilution tests (r = 0.96 to 0.98); 94.3% of the results were +/-1 log(2) dilution between the methods used for both compounds. At a resistance breakpoint of >/=4 microg/ml for both agents, unacceptable false-susceptible or very major errors were noted for colistin (5%) and polymyxin B (6%). Modified zone criteria for colistin (/=14 mm) and polymyxin B (/=14 mm) were suggested, but some degree of error persisted (>/=3.5%). It is recommended that all susceptible disk diffusion results be confirmed by MIC tests using the preferred reference NCCLS method. The quality control (QC) ranges listed in the product package insert require an adjusted range by approximately 3 mm for both NCCLS gram-negative quality control strains. This evaluation of in vitro susceptibility test methods for the polymyxin class drugs confirmed continued serious testing error with the disk diffusion method, the possible need for breakpoint adjustments, and the recalculation of disk diffusion QC ranges. Clinical laboratories should exclusively use MIC methods to assist the therapeutic application of colistin or polymyxin B until disk diffusion test modifications are sanctioned and published by the NCCLS.  (+info)

In vitro pharmacodynamic properties of colistin and colistin methanesulfonate against Pseudomonas aeruginosa isolates from patients with cystic fibrosis. (7/414)

The in vitro pharmacodynamic properties of colistin and colistin methanesulfonate were investigated by studying the MICs, time-kill kinetics, and postantibiotic effect (PAE) against mucoid and nonmucoid strains of Pseudomonas aeruginosa isolated from patients with cystic fibrosis. Twenty-three clinical strains, including multiresistant strains, and one type strain were selected for MIC determination. Eleven strains were resistant; MICs for these strains were >128 mg/liter. For the susceptible strains, MICs of colistin ranged from 1 to 4 mg/liter, while the MICs of colistin methanesulfonate were significantly higher and ranged from 4 to 16 mg/liter. The time-kill kinetics were investigated with three strains at drug concentrations ranging from 0.5 to 64 times the MIC. Colistin showed extremely rapid killing, resulting in complete elimination at the highest concentrations within 5 min, while colistin methanesulfonate killed more slowly, requiring a concentration of 16 times the MIC to achieve complete killing within 24 h. Colistin exhibited a significant PAE of 2 to 3 h at 16 times the MIC against the three strains after 15 min of exposure. For colistin methanesulfonate, PAEs were shorter at the concentrations tested. Colistin methanesulfonate had lower overall bactericidal and postantibiotic activities than colistin, even when adjusted for differences in MICs. Our data suggest that doses of colistin methanesulfonate higher than the recommended 2 to 3 mg/kg of body weight every 12 h may be required for the effective treatment of P. aeruginosa infections in cystic fibrosis patients.  (+info)

Bronchoconstriction following nebulised colistin in cystic fibrosis. (8/414)

Nebulised colistin is regularly used as antipseudomonal therapy in children with cystic fibrosis. We assessed bronchoconstriction in response to nebulised colistin in 58 children. Nebulised colistin significantly reduced FEV(1), MEF(25%), and SaO(2) for 15 minutes. In 20 children the reduction was greater than 10% from baseline FEV(1), and was still at that level in five at 30 minutes. Subjective assessment, baseline FEV(1), and serum IgE were unable to identify susceptible children. It is recommended that children receiving colistin should be carefully assessed for bronchoconstriction.  (+info)