Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones.

BackgroundTo determine the relationship between type three secretion genotype and fluoroquinolone resistance for P. aeruginosa strains isolated from microbial keratitis during the Steroids for Corneal Ulcers Trial (SCUT) and for two laboratory strains, PA103 and PAO1.MethodsConfirmed P. aeruginosa isolates from the SCUT were divided into exoU(+) or exoU(-). The exoU(+) strains contained the gene encoding ExoU, a powerful phospholipase toxin delivered into host cells by the type three secretion system. Isolates were then assessed for susceptibility to fluoroquinolone, cephalosporin, and aminoglycoside antibiotics using disk diffusion assays. Etest was used to determine the MIC of moxifloxacin and other fluoroquinolones. Laboratory isolates in which the exoU gene was added or deleted were also tested.ResultsA significantly higher proportion of exoU(+) strains were resistant to ciprofloxacin (p = 0.001), gatifloxacin (p = 0.003), and ofloxacin (p = 0.002) compared to exoU(-) isolates. There was no significant difference between exoU(+) or exoU(-) negative isolates with respect to susceptibility to other antibiotics except gentamicin. Infections involving resistant exoU(+) strains trended towards worse clinical outcome. Deletion or acquisition of exoU in laboratory isolates did not affect fluoroquinolone susceptibility.ConclusionsFluoroquinolone susceptibility of P. aeruginosa isolated from the SCUT is consistent with previous studies showing elevated resistance involving exoU encoding (cytotoxic) strains, and suggest worse clinical outcome from infections involving resistant isolates. Determination of exoU expression in clinical isolates of P. aeruginosa may be helpful in directing clinical management of patients with microbial keratitis

Association of conjunctival bacterial infection and female sex in cicatricial trachoma.

PURPOSE: Conjunctival infection with non-chlamydial bacteria may play an important role in the progression of trachoma, especially with regard to the development of corneal opacity and blindness. To further characterize the microbiological profile of bacterial conjunctival infections in cicatricial trachoma, a conjunctival swabbing of adults in rural Ethiopia was performed. METHODS: In a cross-sectional study conducted in nine Ethiopian villages with hyperendemic trachoma, persons 40 years of age or older with signs or symptoms consistent with trichiasis were recruited and conjunctival swabbing for bacterial pathogens was performed. RESULTS: Conjunctival examination and swabbing on 112 females and 36 males were performed. Of the 148 study participants, 101 (68.2%) were confirmed to have trichiasis, and 118 (80%) had conjunctival swabs positive for bacteria. In multivariate analyses, growth of pathogenic conjunctival bacteria was independently associated with trichiasis (odds ratio [OR] 6.93; 95% confidence interval [CI] 2.71-17.7) and female sex (OR 5.90; 95% CI 2.09-16.7). Females were more likely to have swabs positive for Streptococcus pneumoniae or Haemophilus influenzae than were males (OR 9.09; 95% CI 1.17-70.8). CONCLUSIONS: In a region of Ethiopia with endemic trachoma, conjunctival bacterial growth was more common in females than that in males. S. pneumoniae and H. influenzae, both of which frequently colonize the nasopharynx of children, were more common in females, suggesting that the preponderance of infection in females may be attributable to close contact with children. This finding is consistent with the theory that childcare activities may preferentially expose females to ocular chlamydial infection. (ClinicalTrials.gov number, NCT00221364.)

Chlamydia on children and flies after mass antibiotic treatment for trachoma.

There are various approaches to control trachoma. These include the elimination of the ocular strains of Chlamydia trachomatis that cause the disease and to decrease the spread of infection by other measures such as fly control. Here, we examined how these two are related (i.e., how treating children with antibiotics affects carriage of Chlamydia by flies). Flies were collected in villages that had received mass oral azithromycin distribution and were compared with flies in untreated villages. Polymerase chain reaction (PCR) was performed to detect chlamydial DNA on the flies. Conjunctival swabs were also taken to assay for chlamydial prevalence in the children. Chlamydia was found on 23% of the flies in the untreated villages but only 0.3% in treated villages. Prevalence of trachoma in children proved to be an excellent predictor of the prevalence on flies (correlation coefficient, 0.89). Thus, treating children with antibiotics may drastically reduce the role of flies as a vector

Eliminating Trachoma in Areas with Limited Disease

The common wisdom is that a trachoma program cannot eliminate ocular chlamydia from a community, just reduce infection to a level where there would be minimal blindness. We describe the success of multiple mass antibiotic treatments, demonstrating that complete elimination of infection may be an attainable goal in an area with modest disease

Uso de propóleo y ε-polilisina como agentes preservantes en yogurt batido

This work studied alternatives to replace conventional preservatives used in the food industry. The objective of this research was to evaluate the effect of the mixture of propolis and ε-polylysine, through statistical analysis, to identify variations in yogurt stability, microbial development, changes in physicochemical properties, shelf life, sensory acceptability and determine the better concentrations of preservatives. Five treatments (T1: 5 mg ε-polylysine – 1 mL Propóleo, T2: 10 mg de ε-polylysine – 0,9 mL de propóleo, T3: 15 mg de ε-polylysine – 0,8 mL de propóleo, T4: 20 mg de ε-polylysine – 0,7 mL de propóleo, y T5: 25 mg de ε-polylysine – 0,6 mL de propóleo) were carried out with a mixture of propolis and ε-polylysine in a completely randomized design with 3 replications. The properties of the preservative in the mixture were analyzed in terms of pH, acidity, count of Staphylococcus aureus, Escherichia coli, molds and yeasts in yogurt stored for 30 days at 4 °C. Significant reduction in pH due to preservatives was observed: T4 - T5 values ​​(4,69; 4,63) higher than T3 - T1 - T2 values ​​(4,39; 4,24; 4,39) are considered more suitable for international standards. In the samples analyzed there was no evidence of the presence of S. aureus, and E. coli. The stability of the product was calculated using the amount of molds and yeasts as an indicator according to the Labuza equation. The sensory analysis was carried out with 75 participants without training, which indicated that the treatment T2 and T3 have the highest overall acceptability.Este trabajo estudió alternativas para sustituir conservantes convencionales utilizados en la industria alimentaria. El objetivo de esta investigación fue evaluar el efecto de la mezcla propóleo y ε-polilisina, a través del análisis estadístico, para identificar variaciones en la estabilidad del yogurt, desarrollo microbiano, cambios en las propiedades fisicoquímicas, vida útil, aceptabilidad sensorial y determinar las mejores concentraciones de conservantes. Se realizaron cinco tratamientos (T1: 5 mg ε-polilisina – 1 mL Propóleo, T2: 10 mg de ε-polilisina – 0,9 mL de propóleo, T3: 15 mg de ε-polilisina – 0,8 mL de propóleo, T4: 20 mg de ε-polilisina – 0,7 mL de propóleo, y T5: 25 mg de ε-polilisina – 0,6 mL de propóleo) con una mezcla de propóleo y ε-polilisina en un diseño completo al azar con 3 repeticiones. Se analizó las propiedades del preservante en la mezcla en términos de pH, acidez, recuento de Staphylococus aureus, Escherichia coli, mohos y levaduras en yogurt almacenado durante 30 días a 4 °C. Se observó reducción significativa en el pH debido a los conservantes: los valores de T4 - T5 (4,69; 4,63) superiores a los valores de T3 - T1 - T2 (4,39; 4,24; 4,39) se consideran más adecuados para los estándares internacionales. En las muestras analizadas no se evidenció presencia de S. aureus, y E. coli. La estabilidad del producto se calculó utilizando como indicador la cantidad de mohos y levaduras según la ecuación de Labuza. El análisis sensorial se llevó a cabo con 75 participantes sin entrenamiento los cuales indicaron que el tratamiento T2 y T3 tienen la aceptabilidad general más alta

The Fitness Cost of Antibiotic Resistance in Streptococcus pneumoniae: Insight from the Field

Laboratory studies have suggested that antibiotic resistance may result in decreased fitness in the bacteria that harbor it. Observational studies have supported this, but due to ethical and practical considerations, it is rare to have experimental control over antibiotic prescription rates.We analyze data from a 54-month longitudinal trial that monitored pneumococcal drug resistance during and after biannual mass distribution of azithromycin for the elimination of the blinding eye disease, trachoma. Prescription of azithromycin and antibiotics that can create cross-resistance to it is rare in this part of the world. As a result, we were able to follow trends in resistance with minimal influence from unmeasured antibiotic use. Using these data, we fit a probabilistic disease transmission model that included two resistant strains, corresponding to the two dominant modes of resistance to macrolide antibiotics. We estimated the relative fitness of these two strains to be 0.86 (95% CI 0.80 to 0.90), and 0.88 (95% CI 0.82 to 0.93), relative to antibiotic-sensitive strains. We then used these estimates to predict that, within 5 years of the last antibiotic treatment, there would be a 95% chance of elimination of macrolide resistance by intra-species competition alone.Although it is quite possible that the fitness cost of macrolide resistance is sufficient to ensure its eventual elimination in the absence of antibiotic selection, this process takes time, and prevention is likely the best policy in the fight against resistance

Antibiotic Selection Pressure and Macrolide Resistance in Nasopharyngeal Streptococcus pneumoniae: A Cluster-Randomized Clinical Trial

Jeremy Keenan and colleagues report that during a cluster-randomized clinical trial in Ethiopia, nasopharyngeal pneumococcal resistance to macrolides was significantly higher in communities randomized to receive azithromycin compared with untreated control communities

Feasibility of eliminating ocular Chlamydia trachomatis with repeat mass antibiotic treatments.

CONTEXT: Mass antibiotic administrations for ocular chlamydial infection play a key role in the World Health Organization's trachoma control program. Mathematical models suggest that it is possible to eliminate trachoma locally with repeat mass treatment, depending on the coverage level of the population, frequency of mass treatments, and rate that infection returns into a community after each mass treatment. Precise estimates of this latter parameter have never been reported. OBJECTIVE: To determine the rate at which chlamydial infection returns to a population after mass treatment and to estimate the treatment frequency required for elimination of ocular chlamydia from a community. DESIGN, SETTING, AND PARTICIPANTS: Longitudinal cohort study of 24 randomly selected villages from the Gurage Zone in Ethiopia conducted February 2003 to October 2003. A total of 1332 children aged 1 to 5 years were monitored for prevalence of ocular chlamydial infection pretreatment and 2 and 6 months posttreatment. INTERVENTIONS: All individuals older than 1 year were eligible for single-dose oral azithromycin treatment. Pregnant women were offered tetracycline eye ointment. MAIN OUTCOME MEASURES: Prevalence of ocular chlamydial infection, measured by polymerase chain reaction, in children aged 1 to 5 years, in each of 24 villages at each time point was used to estimate the rate of return of infection and the treatment frequency necessary for elimination. RESULTS: The prevalence of infection was 56.3% pretreatment (95% confidence interval [CI], 47.5%-65.1%), 6.7% 2 months posttreatment (95% CI, 4.2%-9.2%), and 11.0% 6 months posttreatment (95% CI, 7.3%-14.7%). Infection returned after treatment at an exponential rate of 12.3% per month (95% CI, 4.6%-19.9% per month). The minimum treatment frequency necessary for elimination was calculated to be once every 11.6 months (95% CI, 7.2-30.9 months), given a coverage level of 80%. Thus, biannual treatment, already being performed in some areas, was estimated to be more than frequent enough to eventually eliminate infection. CONCLUSION: The rate at which ocular chlamydial infection returns to a community after mass treatment suggests that elimination of infection in a hyperendemic area is feasible with biannual mass antibiotic administrations and attainable coverage levels

Bacterial Keratitis

PurposeUnderstanding the spectrum of pathogens in a given geographic region is important when deciding on empiric antibiotic therapy. In this study, we evaluate the spectrum of bacterial organisms cultured from corneal samples and their antibiotic sensitivities to guide initial treatment of keratitis.MethodsWe performed a retrospective case review of cultures from suspected infectious keratitis cases at the Francis I. Proctor Foundation, University of California, San Francisco, from 1996 through 2015. Logistic regression models were used to assess the risk of culturing methicillin-resistant Staphylococcus aureus (MRSA) from ulcers over time and the association between the year cultured and moxifloxacin resistance.ResultsA total of 522 of 2203 (23.7%) cultures grew bacterial organisms believed to be the etiology of infection, with available antibiotic sensitivity data. Of these, 338 (65.3%) grew gram-positive organisms with the most common being methicillin-sensitive Staphylococcus aureus (20.1%, N = 105). One hundred eighty (34.7%) grew gram-negative species with Pseudomonas aeruginosa as the most prevalent organism (10.9%, N = 57). There was 1.13 increased odds of culturing MRSA for each 1-year increase in the culture date (P = 0.01) and 1.26 increased odds of culturing an organism resistant to moxifloxacin with each 1-year increase in the culture date after controlling for the infectious organism (P < 0.001).ConclusionsGram-positive organisms are the most commonly identified etiology of microbial keratitis in this series. Approximately 35% of cultured organisms had variable susceptibility to moxifloxacin, and resistance seems to be increasing over time. The risk of culturing MRSA increased over time