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Spectrum of Microbial Keratitis Encountered in the Tropics

Khor HG, Cho I, Lee KRCK, Chieng LL

Eye Contact Lens, 2020 Jan;46(1):17-23.
PMID: 31145209 DOI: 10.1097/ICL.0000000000000621

PURPOSE: To report the predisposing factors, microorganisms, antibiotic sensitivity associated with bacterial keratitis, and treatment outcomes in Miri, Borneo which has a tropical climate.
METHODS: This is a retrospective study on patients presenting with microbial keratitis in Miri, Sarawak, Borneo over a 7-year period from January 1, 2010 until December 31, 2016. Demographic data, predisposing factors, culture and sensitivity results together with treatment outcomes were studied.
RESULTS: There were a total of 221 cases treated as microbial keratitis with a peak age group of 21 to 30 years. The predisposing factors were trauma (49.3%), improper contact lens usage (29.1%), ocular surface diseases (5.9%), ocular surgeries (0.9%), drugs (1.8%), and other factors (19.0%). Occupational injuries among oil palm plantation workers was the leading cause within the trauma cohort (28.8%). Corneal scraping was performed in 189 cases, 61.4% of them yielded positive cultures. The cultures demonstrated that 49.1% were of bacterial origin, 46.6% were fungal, and 4.3% showed mixed growth. The most common bacteria isolated was Pseudomonas aeruginosa, which was sensitive toward ceftazidime and gentamicin antibiotics. One hundred ninety-two cases (86.9%) were treated with purely topical medication, whereas 29 cases (13.1%) required further interventions.
CONCLUSION: The commonest predisposing factor for microbial keratitis was trauma. With the nearby oil palm industries, we report a corresponding increase of incidence in fungal keratitis at our center. Culture and sensitivity reports from corneal scrapings are essential in treatment guidance; however, more than a third of the microbial keratitis cases studied were culture-negative. The organisms cultured reflect the profile expected in tropical climates. Fortunately, there was no increase in resistance rates observed for the commonly used antibiotics.
Waste production from phacoemulsification surgery

Khor HG, Cho I, Lee KRCK, Chieng LL

J Cataract Refract Surg, 2020 02;46(2):215-221.
PMID: 32126034 DOI: 10.1097/j.jcrs.0000000000000009

PURPOSE: To determine the amount of waste produced from phacoemulsification surgeries and ways to curtail the problem.
SETTING: Miri Hospital, Sarawak, Malaysia.
DESIGN: Prospective study.
METHODS: Phacoemulsification surgery cases were included in this study; nonphacoemulsification surgeries were excluded. The waste was subdivided into 3 main categories, general waste, clinical waste, and sharps. The waste produced by ophthalmologists and trainees was accounted for separately. The mean weight of waste per case was obtained by dividing the total weight of waste produced with the total number of cases.
RESULTS: The total waste produced from a total of 203 cases of phacoemulsification surgeries was 167.965 kg, of which, 95.063 kg (56.6%) were clinical waste, 63.197 kg (37.6%) were general waste, and 9.705 kg (5.8%) were sharps; 32.193 kg (50.9%) out of the general waste pool were recyclable waste products. The mean waste production per case of phacoemulsification surgery for an ophthalmologist was 0.814 kg, 1.086 kg per case for a trainee. A case of phacoemulsification surgery would produce 0.282 kg of carbon dioxide equivalents in the setup based on the recyclable general waste.
CONCLUSIONS: The average waste produced per case of phacoemulsification surgery in Miri Hospital was 0.827 kg. After excluding the recyclable material, the average waste produced per case was 0.669 kg. Following the 3 R's principles (reduce, reuse, and recycle) in the handling of waste production might reduce environmental impact.
Fulltext Helminth colonization is associated with increased diversity of the gut microbiota

Lee SC, Tang MS, Lim YA, Choy SH, Kurtz ZD, Cox LM, et al.

PLoS Negl Trop Dis, 2014 May;8(5):e2880.
PMID: 24851867 DOI: 10.1371/journal.pntd.0002880

Soil-transmitted helminths colonize more than 1.5 billion people worldwide, yet little is known about how they interact with bacterial communities in the gut microbiota. Differences in the gut microbiota between individuals living in developed and developing countries may be partly due to the presence of helminths, since they predominantly infect individuals from developing countries, such as the indigenous communities in Malaysia we examine in this work. We compared the composition and diversity of bacterial communities from the fecal microbiota of 51 people from two villages in Malaysia, of which 36 (70.6%) were infected by helminths. The 16S rRNA V4 region was sequenced at an average of nineteen thousand sequences per samples. Helminth-colonized individuals had greater species richness and number of observed OTUs with enrichment of Paraprevotellaceae, especially with Trichuris infection. We developed a new approach of combining centered log-ratio (clr) transformation for OTU relative abundances with sparse Partial Least Squares Discriminant Analysis (sPLS-DA) to enable more robust predictions of OTU interrelationships. These results suggest that helminths may have an impact on the diversity, bacterial community structure and function of the gut microbiota.
Fulltext Linking the effects of helminth infection, diet and the gut microbiota with human whole-blood signatures

Lee SC, Tang MS, Easton AV, Devlin JC, Chua LL, Cho I, et al.

PLoS Pathog, 2019 12;15(12):e1008066.
PMID: 31841569 DOI: 10.1371/journal.ppat.1008066

Helminth infection and dietary intake can affect the intestinal microbiota, as well as the immune system. Here we analyzed the relationship between fecal microbiota and blood profiles of indigenous Malaysians, referred to locally as Orang Asli, in comparison to urban participants from the capital city of Malaysia, Kuala Lumpur. We found that helminth infections had a larger effect on gut microbial composition than did dietary intake or blood profiles. Trichuris trichiura infection intensity also had the strongest association with blood transcriptional profiles. By characterizing paired longitudinal samples collected before and after deworming treatment, we determined that changes in serum zinc and iron levels among the Orang Asli were driven by changes in helminth infection status, independent of dietary metal intake. Serum zinc and iron levels were associated with changes in the abundance of several microbial taxa. Hence, there is considerable interplay between helminths, micronutrients and the microbiota on the regulation of immune responses in humans.
Precessing jet nozzle connecting to a spinning black hole in M87

Cui Y, Hada K, Kawashima T, Kino M, Lin W, Mizuno Y, et al.

Nature, 2023 Sep;621(7980):711-715.
PMID: 37758892 DOI: 10.1038/s41586-023-06479-6

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole1-4. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from general relativity5. With a baseline of 17 years of observations, there was a shift in the jet's transverse position, possibly arising from an 8- to 10-year quasi-periodicity3. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years for the variation in the position angle of the jet. We infer that we are seeing a spinning black hole that induces the Lense-Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.