New treatments for bacterial keratitis.

2012

Wong RL, Gangwani RA, Yu LW, Lai JS.

Source

Eye Institute, The University of Hong Kong, Room 301, Level 3, Block B, 100 Cyberport Road, Cyberport 4, Hong Kong.

Abstract

Purpose. 

To review the newer treatments for bacterial keratitis. 

Data Sources. 

PubMed literature search up to April 2012. Study Selection. Key words used for literature search: "infectious keratitis", "microbial keratitis", "infective keratitis", "new treatments for infectious keratitis", "fourth generation fluoroquinolones", "moxifloxacin", "gatifloxacin", "collagen cross-linking", and "photodynamic therapy". 

Data Extraction. 

Over 2400 articles were retrieved. Large scale studies or publications at more recent dates were selected. 

Data Synthesis. 

Broad spectrum antibiotics have been the main stay of treatment for bacterial keratitis but with the emergence of bacterial resistance; there is a need for newer antimicrobial agents and treatment methods. Fourth-generation fluoroquinolones and corneal collagen cross-linking are amongst the new treatments. In vitro studies and prospective clinical trials have shown that fourth-generation fluoroquinolones are better than the older generation fluoroquinolones and are as potent as combined fortified antibiotics against common pathogens that cause bacterial keratitis. Collagen cross-linking was shown to improve healing of infectious corneal ulcer in treatment-resistant cases or as an adjunct to antibiotics treatment. 

Conclusion. 

Fourth-generation fluoroquinolones are good alternatives to standard treatment of bacterial keratitis using combined fortified topical antibiotics. Collagen cross-linking may be considered in treatment-resistant infectious keratitis or as an adjunct to antibiotics therapy.

PubMed

Assessment of antibiotic resistance in probiotic strain Lactobacillus brevis KB290.

Assessment of antibiotic resistance in probiotic strain Lactobacillus brevis KB290.

J Food Prot. 2009 Sep

Fukao M, Tomita H, Yakabe T, Nomura T, Ike Y, Yajima N.

Probiotics Research Department, Research Institute, Kagome Company, Limited, 17 Nishitomiyama, Nasushiobara, Tochigi, 329-2762, Japan. Masanori_Fukao@kagome.co.jp

Our purpose was to investigate the safety of the probiotic strain Lactobacillus brevis KB290. The European Qualified Presumption of Safety (QPS) evaluation approach was applied to the strain. We determined the strain's antibiotic resistance, verified it at the genetic level, and determined whether it could be transferred to intestinal microflora. Of 14 antibiotics tested, 11 showed MICs within the limits of the QPS criteria. However, the L. brevis KB290 MICs of ciprofloxacin (a fluoroquinolone), tetracycline, and vancomycin were two, four, and eight times, respectively, the breakpoint MICs suggested by the European Scientific Committee on Animal Nutrition, and the MIC of tetracycline was eight times the breakpoint MIC suggested by the European Scientific Panel on Additives and Products or Substances Used in Animal Feed. Using analysis of gapped-genome sequences, we found no known transferable determinants for tetracycline or vancomycin resistance, and we found no mutations in the quinolone resistance-determining regions of the genes encoding GyrA or ParC for ciprofloxacin resistance associated with insertion sequences, integrons, or transposons. These data were confirmed by using PCR primers specific for the respective genes. We assessed the transferability of the resistance traits in conjugation experiments with enterococci and obtained no transconjugants, strongly suggesting that the resistance traits were not transferable. This study demonstrated that the antibiotic resistance observed in L. brevis KB290 was due not to dedicated mechanisms but to intrinsic resistance. According to the QPS criteria, these results provide safety assurance for the ongoing use of L. brevis KB290 as a probiotic.

PMID: 19777895 [PubMed - in process]

Comparative activities of antibiotics against intracellular non-typeable Haemophilus influenzae.

Comparative activities of antibiotics against intracellular non-typeable Haemophilus influenzae.
Wien Klin Wochenschr. 2007 Jun

Kratzer C, Graninger W, Macfelda K, Buxbaum A, Georgopoulos A.
Department of Internal Medicine I, Division of Infectious Diseases and Tropical Diseases, Medical University of Vienna, Vienna, Austria, apostolos.georgopoulos@meduniwien.ac.at.

INTRODUCTION: Non-typeable Haemophilus influenzae (NTHi) is a major bacterial pathogen of community-acquired respiratory tract infection and is usually found extracellularly, although studies have revealed that NTHi may possess the ability to invade human epithelial cells where it is then protected against attack by the local immune system and partly against the effect of antibiotics. The aim of the present study was to assess the ability of ampicillin, azithromycin, telithromycin, ciprofloxacin and moxifloxacin, five antibiotics in common clinical use, to kill NTHi within bronchial epithelial cells.

METHODS: Confluent human bronchial epithelial cells were infected with NTHi 77, a particularly invasive clinical strain. Extracellular bacterial cells were killed with gentamicin and the intracellular bacteria were incubated with antibiotics at concentrations of 1 mg/l or 10 mg/l for 4 h or 8 h. Viable intracellular bacteria were counted after lysis of the epithelial cells.

RESULTS: With the exception of ampicillin, all the antibiotics caused significant reduction of intracellular bacteria at concentrations of 10 mg/l and exposure for 4 h or at 1 mg/l for 8 h. At 1 mg/l, moxifloxacin eliminated 94% of intracellular NTHi after 4 h and 98% after 8 h; ciprofloxacin, azithromycin and telithromycin only achieved killing indices below 75 after 4 h but 86-90% killing after 8 h. At 10 mg/l, moxifloxacin, ciprofloxacin, telithromycin and azithromycin were able to achieve 99.7%, 96.3%, 86.7% and 74.7% eradication of intracellular bacteria, respectively, after exposure for 4 h.

CONCLUSION: These results demonstrate the rapid antibacterial efficacy of moxifloxacin against intracellular NTHi in vitro. Moxifloxacin, which combines high extracellular and intracellular activities, could be an important tool in the treatment of recurrent respiratory tract infections.

PMID: 17571234 [PubMed - as supplied by publisher]