A novel mobile RND-type efflux pump gene cluster, tmexC3D2-toprJ3, confers tigecycline resistance in Pseudomonas alcaligenes

Tigecycline exhibits promising activity against multidrug-resistant gram-negative bacteria (MDR-GNB). However, mobile tigecycline resistance genes, such as tmexCD-toprJ encoding RND efflux pumps, have emerged. Here, we identified a novel tmexC3D2-toprJ3 gene cluster in tigecycline- and carbapenem-nonsusceptible Pseudomonas alcaligenes isolates from hospital sewage in Japan in 2020. tmexC3D2-toprJ3 and two copies of blaIMP-1 were located on the chromosome. This suggests that diverse tmexCD-toprJ-like genes have spread among MDR-GNB worldwide and further epidemiological genomic studies are needed.

The Rhizobacterium Pseudomonas alcaligenes AVO110 Induces the Expression of Biofilm-Related Genes in Response to Rosellinia necatrix Exudates

The rhizobacterium Pseudomonas alcaligenes AVO110 exhibits antagonism toward the phytopathogenic fungus Rosellinia necatrix. This strain efficiently colonizes R. necatrix hyphae and is able to feed on their exudates. Here, we report the complete genome sequence of P. alcaligenes AVO110. The phylogeny of all available P. alcaligenes genomes separates environmental isolates, including AVO110, from those obtained from infected human blood and oyster tissues, which cluster together with Pseudomonas otitidis. Core and pan-genome analyses showed that P. alcaligenes strains encode highly heterogenic gene pools, with the AVO110 genome encoding the largest and most exclusive variable region (~1.6 Mb, 1795 genes). The AVO110 singletons include a wide repertoire of genes related to biofilm formation, several of which are transcriptionally modulated by R. necatrix exudates. One of these genes (cmpA) encodes a GGDEF/EAL domain protein specific to Pseudomonas spp. strains isolated primarily from the rhizosphere of diverse plants, but also from soil and water samples. We also show that CmpA has a role in biofilm formation and that the integrity of its EAL domain is involved in this function. This study contributes to a better understanding of the niche-specific adaptations and lifestyles of P. alcaligenes, including the mycophagous behavior of strain AVO110.

Lignolytic Enzyme Activity of Isolated Bacteria from Termite (Coptotermes Sp.) and Milkfish (Chanos chanos Forsskal, 1775) Guts

Bacteria BSR 2, Pseudomonas alcaligenes (BSR 3), Brevibacillus parabrevis (BSR 8), Brevibacillus sp. (BSR 9), isolated from termite gut and Bacillus licheniformis (BSA B1) isolated from milkfish gut have been known to possess celluloytic activity. However, their lignolytic ability has not been known. This study aimed to determine the lignolytic ability of bacteria isolated from termit (Coptotermes sp.) and milkfish (Chanos chanos Forsskal, 1775) guts and their enzymes characterization. The qualitative test was done through the spot test method, while quantitative assay was performed spectrophotometrically at 335 nm to calculate vanillin concentration. The isolates were grown in Lignin Mineral Medium, then the optical density (OD620) were measured every 24 hours for 5 days using spectrophotometer to determine their growth profile and the best isolation time of the lignolytic enzyme. Based on results, the best lignolytic enzyme isolation time for strains Bacillus licheniformis (BSA B1) and BSR 2 were 5 days, yielding lignolytic enzyme activity of 0.961 ± 0.168 U/mg and 2.176 ± 0.088 U/mg respectively,  while strains Pseudomonas alcaligenes (BSR 3), Brevibacillus parabrevis (BSR 8), and Brevibacillus sp. (BSR 9) were 4 days, yielding of 1.206 ± 0.045 U/mg, 1.162 ± 0.191 U/mg, and 0.896 ± 0.108 U/mg, respectively. The strain BSR 2 showed the highest lignolytic activity compared to other strains. The optimum temperature for lignolytic enzyme activity of BSR 2 was 30 ℃ and the optimum pH was 7. The lignolytic enzyme activity showed that these bacterial isolates can be a chance to be used as new alternative lignolytic enzyme source in commercial bioconversion process.

Nosocomial transmission of a blaVIM-2 carbapenemase integron between isolates of two different Pseudomonas species

We report the first documented in-hospital patient-to-patient-transmission of a blaVIM-2 integron between isolates of Pseudomonas alcaligenes and P. aeruginosa. Molecular typing looking only for difference within species may fail to detect nosocomial transmission of resistance genes.

Bacterial Pneumonia sebagai Salah Satu Penyebab Kematian Lumba Lumba Hidung Botol Indo-Pasifik (Tursiop aduncus)

Lumba-lumba hidung botol Indo-Pasifik (Tursiops aduncus) merupakan jenis lumba-lumba yang banyak ditemukan di perairan Indonesia. Kelestarian T. aduncus perlu mendapat perhatian karena populasinya yang semakin menurun. Upaya pelestarian yang telah dilakukan adalah melalui konservasi. Gangguan respirasi pada lumba-lumba sering ditemukan dan berakibat fatal, salah satu penyakit yang sering ditemukan adalah pneumonia. Pneumonia jenis bronchopneumonia merupakan salah satu gejala infeksi pada paru yang disebabkan oleh bakteri, virus ataupun jamur. Tujuan penelitian ini adalah melakukan isolasi dan identifikasi bakteri yang berperan dalam kejadian pneumonia. Sampel berasal dari seekor lumba lumba jantan yang ada di Pusat Konservasi Mamalia air. Tahapan penelitian ini antara lain isolasi dan identifikasi bakteri dari organ paru-paru yang menunjukkan gejala patologis. Hasil isolasi dan identifikasi ditemukan 2 spesies Gram positif yaitu Staphylococcus epidermidis dan Staphylococcus aureus serta 4 spesies Gram negatif, yaitu Pseudomonas alcaligenes, Actinobacillus delphinicola, Klebsiella sp. dan Serratia marcesens.