Sequence Analysis Of Hsp65 Genes Research Articles

Identification of Mycobacterium chelonae from Lined Seahorse Hippocampus erectus and Histopathological Analysis

The lined seahorse (Hippocampus erectus) is an aquacultural species in China and has important economic and ornamental value. However, the species is affected by disease, which restricts their large-scale cultivation. In 2021, a disease was observed in cultured seahorses in Tianjin, China, with a cumulative mortality rate of 20%. The symptoms observed in the moribund seahorse included a weak swimming capacity, discolored body surface, enlarged liver and kidneys, and numerous white nodules in the parenchymatous organs. The strains HM-2021-1 and HM-2021-2 were isolated from diseased seahorses and were identified as being responsible for the disease. It demonstrated the potential to infect seahorse, and the cumulative mortalities of the seahorses artificially infected with strains HM-2021-1 and HM-2021-2 were 93.3% and 90.0%. The pathogen was identified as Mycobacterium chelonae based on physiological and biochemical tests, and 16S rDNA, rpoB, and Hsp65 gene sequence analysis. To our knowledge, this study is the first report of M. chelonae associated with diseased seahorses in China.

Nocardia seriolae: a serious threat to the largemouth bass Micropterus salmoides industry in Southwest China.

Nocardia seriolae is the causative agent of nocardiosis in both marine and freshwater fish. Here, we report on multiple outbreaks of nocardiosis associated with elevated mortality (23-35%) in farmed largemouth bass in Sichuan, China, from 2017 to 2018. A total of 9 strains isolated from diseased largemouth bass were identified as N. seriolae by phenotypic characterization, 16S rRNA and hsp65 gene sequence analysis. The clinical signs of infected largemouth bass included hemorrhage, skin ulcers and prominent tubercles varying in size in the gill, liver, spleen and kidney. Experimental infection indicated that these isolates were the pathogens responsible for the mortalities. In vitro antibacterial activities of 12 antibiotics against N. seriolae isolates were determined as minimum inhibitory concentrations. Histopathological observation of diseased fish infected with N. seriolae showed necrotizing granulomatous hepatitis, nephritis, splenitis, epithelial hypertrophy and hyperplasia with degenerative changes of the epithelium in the gill. Large quantities of bacterial aggregates were found in the necrotic area of the granuloma by Lillie-Twort Gram stain and immunocytochemistry. Our findings indicated that N. seriolae is a serious threat to the largemouth bass Micropterus salmoides industry in Southwest China.

Imaging Findings of Pulmonary Nocardiosis Mimicking Bronchiectasis.

Nocardia species usually cause opportunistic infections, and the frequency of these infections is increasing owing to the growing population of immunocompromised hosts. However, Nocardia may sometimes causes an infectious disease in immunocompetent hosts. Herein, we report two cases of pulmonary nocardiasis in immunocompetent individuals, whose chest computed tomography (CT) findings mimicked bronchiectasis. Samples of bronchalveolar lavage (BAL) fluid obtained by bronchoscopy showed filamentous, branching, gram-positive rods, acid-fast filamentous branching rods, and a colony of suspected Nocardia was cultured. Based on 16sRNA and hsp65 gene sequence analysis, case 1 was identified as N. cyriacigeorgica, but case 2 was not matched. The patients responded well to treatment with the combination of sulfamethoxazole and linezolid.

Bilateral Sporotrichoid Cutaneous Infection by Mycobacterium haemophilum in a Chinese Patient with Systemic Lupus Erythematosus

We report a case of an immunocompromised 30-year-old woman with systemic lupus erythematosus (SLE) with bilateral sporotrichoid cutaneous infection caused by M. haemophilum. The patient initially presented with painful deep erythematous nodules and ulcerations on her left forearms for several months. These nodular lesions were arranged along the lymphatic path and became suppurative, ulcerative, and crusted. Subsequently, the symmetrical part of the dorsum of the patient’s right hand showed a similar nodular lesion (Fig. 1A–C). Eight years earlier, she was diagnosed with SLE and intermittently treated with steroid therapy (dosage was unknown), however, the facial rash still relapsed. Currently, the patient is receiving 20 mg prednisone once daily. Her medical history revealed no other systemic diseases and she denied any preceding history of trauma, gardening, or dealing with fish tanks. Laboratory examination showed the platelets were 23 × 109/l (normal: 100–300 × 109/l) and the hemoglobin was 105 g/l (normal: 110–150 g/l). Urine routine examination showed proteinuria and occult blood. Immunological findings included positive results for ANA (1:1,000), anti-RNP, and anti-SSA. The purified protein derivative (PPD) test and human immunodeficiency virus (HIV) antibody test were negative. Histological examination of an erythematous nodule on the patient’s left forearm revealed an abscess and granulomas without caseous necrosis in the superficial and mid-dermis, which involved mainly neutrophils, as well as lymphocytes, histiocytes, plasmocytes, and a small amount of eosinophils (Fig. 1D, E). The epidermis was mildly hyperplastic and Ziehl–Neelsen staining of the histopathology lesions revealed acid-fast bacilli (AFB) (Fig. 1F). Other specific stains, such as periodic acid Schiff and Giemsa stains, for microorganisms were negative. Biopsy specimen culture for mycobacteria on a Lowenstein–Jensen medium was negative. Therefore, a direct sequencing protocol targeting hsp 65 and 16S rRNA genes of mycobacterium was applied in the tissue specimen. Sequence analysis of hsp65 genes indicated 100% homology with the M. haemophilum strain ATCC 29548, and 16S rRNA genes showed 99% similarity with M. haemophilum strain DSM 44634. Gene sequences were analysed using BLAST V2.0 software avail able at http://www.ncbi.nlm.nih.gov/BLAST/. The organism, when biopsy specimens were cultured for the second time on a blood Bilateral Sporotrichoid Cutaneous Infection by Mycobacterium haemophilum in a Chinese Patient with Systemic Lupus Erythematosus

Evaluation of PCR–RFLP analysis targeting hsp65 and rpoB genes for the typing of mycobacterial isolates in Malaysia

In this study, PCR-RFLP analysis (PRA) targeting hsp65 and rpoB gene regions was evaluated for the identification of mycobacterial species isolated from Malaysian patients. Overall, the hsp65 PRA identified 92.2 % of 90 isolates compared to 85.6 % by the rpoB PRA. With 47 rapidly growing species, the hsp65 PRA identified fewer (89.4 %) species than the rpoB PRA (95.7 %), but with 23 slow-growing species the reverse was true (91.3 % identification by the hsp65 PRA but only 52.5 % by the rpoB PRA). There were 16 isolates with discordant PRA results, which were resolved by 16S rRNA and hsp65 gene sequence analysis. The findings in this study suggest that the hsp65 PRA is more useful than the rpoB PRA for the identification of Mycobacterium species, particularly with the slow-growing members of the genus. In addition, this study reports 5 and 12 novel restriction patterns for inclusion in the hsp65 and rpoB PRA algorithms, respectively.

Hip Prosthesis Infection Due to Mycobacterium wolinskyi

Mycobacterium wolinskyi, first described in 1999, is a rapidly growing mycobacterium related to the Mycobacterium smegmatis group. Only eight cases of infection due to this microorganism have been reported, including three cases of bone infection. Here, we present the first case of a joint prosthesis infection cured with the combination of surgery and prolonged antibiotic therapy. The microorganism was identified by biochemical tests and 16S rRNA and Hsp65 gene sequence analysis.