Hybrid Vibrio cholerae El Tor Lacking SXT Identified as the Cause of a Cholera Outbreak in the Philippines

Abstract

Cholera continues to be a global threat, with high rates of morbidity and mortality. In 2011, a cholera outbreak occurred in Palawan, Philippines, affecting more than 500 people, and 20 individuals died. Vibrio cholerae O1 was confirmed as the etiological agent. Source attribution is critical in cholera outbreaks for proper management of the disease, as well as to control spread. In this study, three V. cholerae O1 isolates from a Philippines cholera outbreak were sequenced and their genomes analyzed to determine phylogenetic relatedness to V. cholerae O1 isolates from recent outbreaks of cholera elsewhere. The Philippines V. cholerae O1 isolates were determined to be V. cholerae O1 hybrid El Tor belonging to the seventh-pandemic clade. They clustered tightly, forming a monophyletic clade closely related to V. cholerae O1 hybrid El Tor from Asia and Africa. The isolates possess a unique multilocus variable-number tandem repeat analysis (MLVA) genotype (12-7-9-18-25 and 12-7-10-14-21) and lack SXT. In addition, they possess a novel 15-kb genomic island (GI-119) containing a predicted type I restriction-modification system. The CTXΦ-RS1 array of the Philippines isolates was similar to that of V. cholerae O1 MG116926, a hybrid El Tor strain isolated in Bangladesh in 1991. Overall, the data indicate that the Philippines V. cholerae O1 isolates are unique, differing from recent V. cholerae O1 isolates from Asia, Africa, and Haiti. Furthermore, the results of this study support the hypothesis that the Philippines isolates of V. cholerae O1 are indigenous and exist locally in the aquatic ecosystem of the Philippines.

Phylogenetic Diversity of Vibrio cholerae Associated with Endemic Cholera in Mexico from 1991 to 2008

“…Lack of the SXT/R391 ICE in epidemic strains isolated in Latin America in the 1990s has been reported ( 8 ). Absence of the SXT/R391 ICE among V. cholerae isolates has also been reported in a recent cholera outbreak in the Philippines ( 41 ). Antibiotic susceptibility analyses of the five Mexican isolates, CP1030, CP1032, CP1035, CP1037, and 95412, revealed all were sensitive to penicillin, ampicillin, streptomycin, chloramphenicol, trimethoprim-sulfamethoxazole, tetracycline, kanamycin, erythromycin, nalidixic acid, and ciprofloxacin.…”

Retrospective Molecular-Epidemiological Analysis of Cholera Epidemic in the Republic of Dagestan in 1994

“…данный кластер генов (инте-гративный коньюгативный элемент «индийского» типа SXT-ICE-Ind) является типичным для эпидеми-ческих штаммов, выделенных в бангладеш, индии в 1990-е годы. вместе с тем у штаммов № 17261-рд и 18329-к SXT-элемент отсутствовал, что с учетом данных о преимущественном выделении штаммов, лишенных SXT, из водных источников [21,23] мо-жет подтверждать имевшую место реализацию со-ответствующего пути распространения возбудителя инфекции во время эпидемии холеры в республике дагестан [6] и вспышки в казани, обусловленной идентичными клиническими штаммами и штамма-ми из объектов окружающей среды [8].…”

“…необходимо отметить, что све-дения о генетически измененных (содержащих ал-лель ctxB Class ) вариантах V. cholerae O1 биовара эль тор, появившиеся впервые в 2002 г., к настоящему времени значительно расширились в плане изучения структуры генома, функций генов, филогеномики штаммов [18,19,20,21,24,26,28]. генотипы штам-мов V. choleraе о1, несущих классический аллель ctxB-1, обнаруженные в индии, распространились в другие страны азии и в африку, а имеющие клас-сический аллель ctxB-7 -в страны азии, африки и на американский континент.…”

Phenotypic characterization of marine phage cocktail from Batangas Philippines against Multi-Drug Resistant Pseudomonas aeruginosa, Methicillin Resistant Staphylococcus aureus, and Vibrio cholera

“…Marine bacteriophages, in spite of their ubiquitous nature in pelagic ecosystems have only been extensively studied for about thirty years. Thus, the information about the architectural features of the phages is limited and substantially less than the Manuscript received Dec. 4 terrestrial phages (Kuznetsov et al, 2013).…”

“…In unexplored aquatic areas in the Philippines, there is a lack morphological analyses of phages and application against antibiotic resistant bacteria (Sulcius et al, 2011;Vital et al, 2014; D.C. Klinzing et al, 2015). Recent phage research and identification focuses on molecular and virus genome analyses, but the size of the genome can provide only an estimate of the rates of ecological interactions between phage and the host, as well as the synergistic or antagonistic relationships among phages.…”