Survival of Pseudomonas aeruginosa in M-K preserved corneas (original) (raw)
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Biomédica : revista del Instituto Nacional de Salud
An endophthalmitis following penetrating keratoplasty by Pseudomonas aeruginosa is a devasting case with very poor visual outcomes. To determine the origin of an infection after a penetrating keratoplasty. After an endophthalmitis an epidemiological study was undertaken with the approval of the ethics committee and support of a medical team comprised of an epidemiologist, infectologist, bacteriologist and ophthalmologists specializing in cornea. Factors that may have contributed to the risk of infection were assessed, for example, the processing and preservation of the cornea in the moment of the extraction, the characteristics of the donor, recipient and infecting bacterium, as well as the details pertaining to the surgical operation. No risks factors were found in the institution, in the eye bank facilities, in the donor or in the receptor. However, sterile technique could not be guaranteed in the morgue where the corneal extraction occurred, and other isolated cases of endophthal...
Phenotype of Pseudomonas aeruginosa Isolates Causing Corneal Infection Between 1997 and 2000
Cornea, 2003
Purpose. To investigate the relationship between functional phenotype of Pseudomonas aeruginosa and the associated human corneal infection. Methods. This was an experimental pilot study of patients presenting with corneal infections at the Jules Stein Eye Institute with presumed P. aeruginosa infection during the period from 12/30/97 to 9/1/00. Thirteen patients were admitted to the study based on positive identification of the causative pathogen as P. aeruginosa and patient consent. Data were collected (including bacterial cultures, lens wear schedule and care, gender and age, completed history questionnaire, clinical photographs). Statistical analysis of possible correlations was performed. Phenotypes of P. aeruginosa were determined, and clinical factors associated with infection were explored. Results. Both invasive and cytotoxic phenotypes of P. aeruginosa were isolated in equal proportion. Cytotoxic strains and invasive strains were found to be associated with patients younger than 50 years of age and older than 50 years of age, respectively. Conclusions. P. aeruginosa remains a significant pathogen in corneal infection, especially during contact lens wear. The age of the patient may influence the phenotype of P. aeruginosa causing infection. Since invasive and cytotoxic strains have different effects on corneal cells, treatment of the infection might require different approaches depending on this phenotype of the causative bacteria.
Managing delayed onset postoperative Pseudomonas aeruginosa endophthalmitis
Indian Journal of Clinical and Experimental Ophthalmology
A 58 year old female patient presented with diminution of vision in left eye a week after uneventful manual small incision cataract surgery. Examination showed ciliary congestion, hypopyon and exudative papillary membrane. AC wash was done and intravitreal antibiotics were given. Vitreous tap revealed Pseudomons aeruginosa, sensitive to ciprofloxacin amikacin, ceftazidime. Endophthalmitis due to a potentially virulent organism improved on appropriate intravitreal antibiotics, not requiring any vitrectomy. Prompt treatment with appropriate intravitreal antibiotics is the most important step in the management of postoperative endophthalmitis.
The pathogenesis of bacterial keratitis: studies with Pseudomonas aeruginosa
Clinical and Experimental Optometry, 2002
Bacterial infection of the cornea (Figure 1) is considered a relatively rare but serious medical condition requiring urgent medical attention because of the potential for reduced vision or even vision loss in the affected eye(s). Predisposing factors for infectious keratitis include the extended or overnight wear of soft contact lenses; 1,2 ocular surgical procedures, for example, LASIK; 3 ocular disease and ocular injury. 4 Bacteria isolated from patients with keratitis include a variety of gram-positive and gram-negative organisms such as Staphylococcus spp., Streptococcus spp., Pseudomonas spp. and Serratia spp. Infecting bacteria are likely to be derived from environmental sources, patients' normal skin and nasopharyngeal flora, contact lens care solutions or lens cases, topical drug or irrigation solutions or ocular instruments. Continued incidence of infectious keratitis, 1,2,4 increasing antibiotic REVIEW The pathogenesis of bacterial keratitis: studies with Pseudomonas aeruginosa
Microbiological Profile of Donor Corneas
Cornea, 2008
Purpose: To study the microbiological profile and the antibiotic sensitivity of the microorganisms cultured from donor corneas and evaluate with respect to the decontamination protocols during the study period. Methods: Retrospective review of microbiological culture reports of 2291 donor eyes sent from January 2000 to December 2003. Donor corneas were treated with 0.4% gentamicin (phase I), 1% povidoneiodine and 0.4% gentamicin (phase II), and 5% povidone-iodine with 0.4% amikacin (phase III). Limbal swabs taken by the eye bank technician after antimicrobial decontamination of donor eyes and sent to the microbiology laboratory for culture were tracked. The positive culture reports with antibiotic sensitivity pattern were studied and results correlated with decontamination protocols. Results: Staphylococcus epidermidis, Pseudomonas aeruginosa, and Alkaligenes faecalis were the 3 most common isolates overall. The percentage of positive bacterial cultures reduced when we used 5% povidone-iodine and 0.4% amikacin (31.3%) as compared to 1% povidone-iodine and 0.4% gentamicin (61.8%) (P , 0.001). Addition of povidone-iodine decreased positive fungal cultures from 6% in phase I to 2.2% in phase II (P , 0.01) and 1.9% in phase III (P , 0.01). Amongst the total bacterial cultures sent after antimicrobial treatment, Gram-positive bacteria decreased from 38.6% (64/166) in phase I to 27.6% (402/1457) and 10.8% (72/668) in phases II and III, respectively (P , 0.001), and Gram-negative bacteria increased from 10.2% (17/166) to 18.8% (274/1457) and 19.8% (132/668), respectively (P = 0.02). Amongst the positive bacterial cultures, the proportion of Gram-positive bacteria decreased from 79.0% (64/81) in phase I to 59.5% (402/676) and 35.3% (72/204) in phases II and III, respectively (P , 0.001), and that of Gram-negative bacteria increased from 21.0% (17/81) to 40.5% (274/676) and 64.7% (132/204), respectively (P , 0.001). Conclusions: Different combinations of antimicrobials failed to eliminate all organisms, especially Gram-negative bacteria from the donor corneal surface. The increase in proportion of Gram-negative bacteria despite the use of amikacin combined with povidone-iodine suggests a need to find a better combination for decontamination of donor corneal tissue.
An Outbreak of Post-Cataract Surgery Endophthalmitis Caused by Pseudomonas aeruginosa
Ophthalmology, 2009
Infectious endophthalmitis is among the most serious complications of cataract surgery. Gram-negative bacteria, including Pseudomonas aeruginosa, are responsible for less than 30% of cases; however, their rapidity of infection and virulence often results in poor visual outcome despite prompt antibiotic treatment. The purpose of this study was to investigate an outbreak of post-cataract surgery P. aeruginosa endophthalmitis in India. Hospital-based case series. Twenty patients with acute postoperative endophthalmitis who underwent cataract surgery at one of the peripheral centers of Joseph Eye Hospital, Tiruchirapalli, Tamil Nadu, India, from February 23 to April 2, 2008. Vitreous aspirates and environmental surveillance specimens were inoculated for culture. Antibiotic susceptibility testing was performed by agar diffusion method. Polymerase chain reaction (PCR) with enterobacterial repetitive intergenic consensus (ERIC) primers (ERIC-PCR) was used to establish the clonal relationship between clinical and environmental isolates. Post-cataract surgery P. aeruginosa endophthalmitis. Pseudomonas aeruginosa was isolated from 20 eyes with postoperative endophthalmitis, the phacoemulsifier's internal tubes, the povidone-iodine solution, and the operating theater air-conditioning system. All strains were multidrug-resistant to cefazolin, chloramphenicol, tetracycline, aminoglycosides, and fluoroquinolones; conversely, most of them were susceptible to polymyxin B. Polymerase chain reaction with enterobacterial repetitive intergenic consensus primers disclosed 2 major clusters: six genetically identical clinical isolates shared 94% of similarity with the air-conditioning isolate; 11 other clinical isolates had 88% of similarity with the former strain. Despite the prompt use of intravitreal antibiotics, 10 patients had evisceration or phthisis of the affected eye. The outcome of cataract surgery-related P. aeruginosa endophthalmitis is poor. The detection of multidrug-resistant isolates is a serious problem, jeopardizing an appropriate choice of treatment. Polymerase chain reaction with enterobacterial repetitive intergenic consensus results strongly suggest that the main source of infection in this outbreak was the contaminated air-conditioning system. Polymerase chain reaction with enterobacterial repetitive intergenic consensus is an inexpensive, fast, reproducible, and discriminatory DNA typing tool for effective epidemiologic surveillance of clinical and environmental isolates of P. aeruginosa.
Keratitis caused by Pseudomonas aeruginosa: treatment in the experiment
2020
The aim of the study was to investigate the effectiveness of treatment of keratitis caused by Pseudomonas aeruginosa using official ophthalmic forms of antibiotics, which are effective against the pathogen. Materials and methods. Adult 36 rabbits weighing 3–3.5 kg were undergone the causing of purulent keratitis by applying a clinical strain of P. aeruginosa as a suspension of one-day culture of the microorganism at a concentration of 5×10 8 CFU/ml on the partially de-epithelialized (approximately 1 cm 2 ) cornea followed by coating for 24 hours with soft contact lens made of belafilcon A (water content: 36 %, oxygen permeability DK/t:110.0). In half of the cases, microbial biofilms were pre-grown on the contact lens surfaces via incubation into the broth culture of P. aeruginosa strain. The treatment of keratitis was performed with ocular official forms of antibiotics: levofloxacin 0.5 % (5 mg/ml), ciprofloxacin 0.3 % (3 mg/ml), tobramycin 0.3 % (3 mg/ml). Their effectiveness again...
Pseudomonas aeruginosa survival and multiplication within corneal epithelial cells in vitro
Infection and Immunity
Pseudomonas aeruginosa is usually considered an extracellular pathogen. Using assays to determine intracellular survival in the presence of gentamicin, we have previously demonstrated that P. aeruginosa is able to invade corneal cells during infectious keratitis in mice. In vitro, P. aeruginosa was found to enter the following cells: human corneal cells removed by irrigation; epithelial cells in the cornea of rats, mice, and rabbits; and primary corneal epithelial cells cultured from rat and rabbit eyes. The level of invasion was related to the level of adherent or associated bacteria. In general, invasion was more efficient with cultured epithelial cells than with cells tested in situ. Invasion did not occur when assays were performed at 4؇C. Cytochalasin D but not colchicine inhibited bacterial invasion, suggesting that bacterial entry was an endocytic process dependent on actin microfilaments but not microtubules. Bacteria that invaded cultured corneal epithelial cells were found to multiply within cells. The ability of P. aeruginosa to invade and multiply within corneal epithelial cells may contribute to the virulence of this organism during infectious keratitis, since intracellular bacteria can evade host immune effectors and antibiotics commonly used to treat infection.
Biomédica, 2010
Introduction. An endophthalmitis following penetrating keratoplasty by Pseudomonas aeruginosa is a devasting case with very poor visual outcomes. Objective. To determine the origin of an infection after a penetrating keratoplasty. Materials and methods. After an endophthalmitis an epidemiological study was undertaken with the approval of the ethics committee and support of a medical team comprised of an epidemiologist, infectologist, bacteriologist and ophthalmologists specializing in cornea. Factors that may have contributed to the risk of infection were assessed, for example, the processing and preservation of the cornea in the moment of the extraction, the characteristics of the donor, recipient and infecting bacterium, as well as the details pertaining to the surgical operation. Results. No risks factors were found in the institution, in the eye bank facilities, in the donor or in the receptor. However, sterile technique could not be guaranteed in the morgue where the corneal extraction occurred, and other isolated cases of endophthalmitis post-keratoplasty had been documented involving tissues from the same morgue that had been processed by two eye banks in the same city. Characteristics of the multi-resistant Pseudomonas sp. demonstrated its origin from a hospital environment due to its previous exposure to a variety of antibiotics. Conclusions. Corneal extraction site must guarantee an antiseptic preparation and aseptic tissue donor recuperation; although in this study it was not feasible to accurately establish the infection source, all of the findings led to suspect a possible contamination at the morgue.