In recent years, nosocomial infections due to multidrug resistant Klebsiella pneumoniae strains have been increasing, associated with growing trend of resistance to beta-lactams and fluoroquinolones (FQs) worldwide. In this study, prevalence of beta-lactamase genes and resistance mechanisms to FQ were analyzed in 191 clinical K. pneumoniae isolates derived from respiratory tract infections in a teaching hospital in Yangon, Myanmar. The major extended-spectrum beta-lactamase gene was bla_CTX-M, which was detected in 33% of isolates, with CTX-M-15 being dominant. Fourteen isolates (7.3%) harbored carbapenemase genes that were genotyped as bla_NDM-1, bla_NDM-5, or bla_NDM-7. The most common plasmid-mediated quinolone resistance (PMQR) gene was aac6′-Ib-cr (51.8%), followed by qnrB (41.9%), oqxAB (23%), and qnrS (15.2%). In quinolone-resistance determining region of GyrA, eight different types of mutation were identified for FQ-resistant isolates, with double mutations at two positions (S83F, D87A) being most common (54.6%). Isolates with double mutations (three patterns) showed higher minimal inhibitory concentration to levofloxacin (LVX) (≥64 μg/mL) than those with a single mutation. PMQR gene profiles, including aac6′-Ib-cr and any other gene(s), were generally related to higher resistance level to LVX. K. pneumoniae isolates with different profiles of beta-lactamase genes and FQ-resistance determinants were mostly classified into ST15 or its single-locus variant (SLV). The most common NDM gene, bla_NDM-5, was detected in ST975 (ST15-SLV) isolates and an ST4000 isolate. The present study revealed the wide spread of FQ-resistant K. pneumoniae clinical isolates acquiring various FQ-resistance determinants and beta-lactamases that were presumably derived from a single clonal lineage in a hospital in Myanmar.

中文翻译：

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缅甸呼吸道感染肺炎克雷伯菌临床分离株中超广谱β-内酰胺酶/碳青霉烯酶基因和喹诺酮耐药性决定因素的流行。

近年来，由多重耐药肺炎克雷伯菌菌株引起的医院感染不断增加，这与世界范围内对β-内酰胺类和氟喹诺酮类（FQs）耐药性的增长趋势有关。在这项研究中，在缅甸仰光的一家教学医院中，对源自呼吸道感染的191株临床肺炎克雷伯菌分离株中 β-内酰胺酶基因的流行情况和对 FQ 的耐药机制进行了分析。主要的超广谱 β-内酰胺酶基因是bla _CTX-M，在 33% 的分离株中检测到，其中 CTX-M-15 占优势。14 个分离株 (7.3%) 含有碳青霉烯酶基因，这些基因被基因分型为bla _NDM-1、bla _NDM-5或bla _NDM-7。最常见的质粒介导的喹诺酮抗性（PMQR）基因是aac6'-IB-CR（51.8％），其次是qnrB（41.9％），oqxAB（23％），和qnrS（15.2％）。在 GyrA 的喹诺酮类耐药决定区，FQ 耐药菌株有 8 种不同类型的突变，其中两个位置的双突变（S83F、D87A）最为常见（54.6%）。双突变（三种模式）的分离株对左氧氟沙星（LVX）的最小抑制浓度（≥64 μg/mL）高于单突变的分离株。PMQR 基因谱，包括aac6'-Ib-cr和任何其他基因，通常与对LVX 的较高抗性水平有关。肺炎克雷伯菌具有不同 β-内酰胺酶基因谱和 FQ 抗性决定簇的分离株大多被分类为 ST15 或其单基因座变异 (SLV)。最常见的 NDM 基因bla _NDM-5在 ST975 (ST15-​​SLV) 分离株和 ST4000 分离株中检测到。本研究揭示了获得各种 FQ 抗性决定簇和 β-内酰胺酶的 FQ 抗性肺炎克雷伯菌临床分离株的广泛传播，它们可能来自缅甸一家医院的单克隆谱系。