Bacteria have proven its worth as a bioindicator in many fields. Therefore, the characterization of native coral bacteria is essential as they could be used as an indicator of coral health status. For this, bacteria are isolated from the healthy and bleached state of two dominant corals (Porites spp. and Turbinaria spp.) collected in the winter and summer seasons from the Gulf of Kutch (GoK), Gujarat, India. These isolates are evaluated for their antibiotic resistance (AR) and antagonistic activity as these bacterial properties are important to compete with the host and other microbes for nutrients and space on the coral surface. The average multiple antibiotic resistance (MAR) index on the healthy coral surface (0.20 ± 0.01) is more compared to the MAR on the bleached coral surface (0.18 ± 0.01) suggesting the microbes on healthy coral surface has high AR ability. Similarly, the MAR index in summer (0.21 ± 0.01) is higher than the MAR index in winter (0.17 ± 0.01) season indicates an increase in the microbial load and competition with the increase in sea surface temperature (SST). Porites spp. (0.20 ± 0.02) have slightly more MAR than Turbinaria spp. (0.19 ± 0.01). Further, isolates with high MAR index are selected for antagonistic assay and overall results suggest that the antagonistic activity of bacteria from the healthy coral surface (83%) are slightly more compared to the isolates from bleached coral surface (78%). The AR profile and antagonistic activity of bacteria associated with corals would be helpful for preliminary screening of native or pathogenic bacteria of corals, which could be used as the indicator of coral health status or could form the basis for developing quantitative tools for predicting the coral health status.

细菌已在许多领域证明了其作为生物指示剂的价值。因此，表征本地珊瑚细菌至关重要，因为它们可以用作珊瑚健康状况的指标。为此，从两种主要珊瑚（Porites spp。和Turbinaria）的健康和漂白状态中分离出细菌spp。）在冬季和夏季从印度古吉拉特邦的库奇湾（GoK）收集。对这些分离物的抗生素抗性（AR）和拮抗活性进行了评估，因为这些细菌特性对于与宿主和其他微生物争夺珊瑚表面的营养和空间很重要。健康珊瑚表面的平均多重抗生素抗性（MAR）指数（0.20±0.01）高于漂白珊瑚表面的MAR（0.18±0.01），表明健康珊瑚表面的微生物具有较高的AR能力。同样，夏季的MAR指数（0.21±0.01）高于冬季的MAR（0.17±0.01）季节，这表明微生物负荷增加，并且随着海表温度（SST）的增加而竞争。多孔性spp。（0.20±0.02）的MAR稍高于Turbinaria spp。（0.19±0.01）。此外，选择具有高MAR指数的分离物进行拮抗测定，总体结果表明，健康珊瑚表面细菌的拮抗活性（83％）比漂白珊瑚表面细菌的拮抗活性（78％）略高。与珊瑚有关的细菌的AR分布和拮抗活性将有助于初步筛选珊瑚的原生或致病细菌，这些细菌可用作珊瑚健康状况的指标，或为开发定量工具以预测珊瑚健康提供基础状态。