Román-Román Adolfo, Martínez-Santos Verónica I, Castañón-Sánchez Carlos A, Albañil-Muñoz Alan J, González-Mendoza Paola, Soto-Flores Diana G, Martínez-Carrillo Dinorah N, Fernández-Tilapa Gloria
1Laboratorio de Investigación en Bacteriología, Facultad de Ciencias Químico-Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n C.U. Sur., C.P. 39090 Chilpancingo, Guerrero Mexico.
2Universidad Autónoma de Guerrero, Av. Javier Méndez Aponte No. 1, Fracc. 10, Col. Servidor Agrario, C.P. 39070 Chilpancingo, Guerrero Mexico.
Gut Pathog. 2019 Feb 13;11:5. doi: 10.1186/s13099-019-0286-9. eCollection 2019.
is a Gram-negative bacterium that colonizes the gastric mucosa in humans. One of the main virulence factors of is the pathogenicity island (PAI), which encodes a type 4-secretion system (T4SS) and the cytotoxin CagA. Translocation of CagA through the T4SS triggers host-signaling pathways. One of the T4SS proteins is CagL, which is necessary for CagA translocation. CagL is a 26-kDa protein that contains a hypervariable motif, which spans residues 58 to 62. Several polymorphisms in this region have been associated with different disease outcomes, e.g. in Mexico, N58 is associated with a higher risk of gastric cancer. The aim of this work is to analyze the sequence of the hypervariable motif (residues 58 to 62) of clinical isolates from Mexican patients with chronic gastritis, and to correlate these polymorphisms with the genotype.
Of the 164 biopsies analyzed, only 30.5% (50/164) were positive for . Thirty-six of the 50 clinical isolates (72%) were positive, and 40 (80%) had the most virulent genotype (s1/m1). Of the positive strains, 94.4% were s1/m1. All the strains contained the gene. The most prevalent sequence in the polymorphic region (residues 58-62) was DKMGE (75.8%, 25/33), followed by NKMGQ and NEIGQ (6.1%, 2/33), and DEIGQ, NKMGE, DKIGE, and DKIGK (3%, 1/33). Regarding polymorphisms in positions 58 and 59, the most common were D58/K59 (81.8%, 27/33), followed by N58/K59 (9.1%, 3/33), and D58/E59 (3%, 1/33). Only two isolates (6.1%) contained residues N58/E59, which correspond to those found in strain ATCC 26695. 92.6% of the clinical isolates having polymorphism D58/K59 had the genotype s1/m1, considered to be the most virulent, while 7.4% had the genotypes s1/m2 and s2/m2.
In Mexican patients, CagL polymorphisms D58, K59, M60, E62, K122, and I134 are more common in patients with chronic gastritis.
是一种革兰氏阴性菌，可在人类胃黏膜定植。其主要毒力因子之一是致病岛（PAI），该致病岛编码一种IV型分泌系统（T4SS）和细胞毒素CagA。CagA通过T4SS的易位会触发宿主信号通路。T4SS蛋白之一是CagL，它是CagA易位所必需的。CagL是一种26 kDa的蛋白质，包含一个高变基序，该基序跨越第58至62位氨基酸残基。该区域的几种多态性与不同的疾病结局相关，例如在墨西哥，N58与胃癌风险较高相关。这项工作的目的是分析来自墨西哥慢性胃炎患者临床分离株的高变基序（第58至62位氨基酸残基）序列，并将这些多态性与基因型相关联。
在分析的164份活检样本中，只有30.5%（50/164）对呈阳性。50株临床分离株中有36株（72%）呈阳性，40株（80%）具有毒性最强的基因型（s1/m1）。在阳性菌株中，94.4%为s1/m1。所有菌株均含有基因。多态性区域（第58 - 62位氨基酸残基）中最常见的序列是DKMGE（75.8%，25/33），其次是NKMGQ和NEIGQ（6.1%，2/33），以及DEIGQ、NKMGE、DKIGE和DKIGK（3%，1/33）。关于第58和59位的多态性，最常见的是D58/K59（81.8%，27/33），其次是N58/K59（9.1%，3/33），以及D58/E59（3%，1/33）。只有两株分离株（6.1%）含有N58/E59残基，这与菌株ATCC 26695中发现的残基相对应。具有多态性D58/K59的临床分离株中，92.6%具有被认为是毒性最强的基因型s1/m1，而7.4%具有基因型s1/m2和s2/m2。
在墨西哥患者中，CagL多态性D58、K59、M60、E62、K122和I134在慢性胃炎患者中更为常见。
