Mycobacterium tuberculosis Isolates from Single Outpatient Clinic in Panama City Exhibit Wide Genetic Diversity

Abstract

Abstract. Understanding Mycobacterium tuberculosis biodiversity and transmission is significant for tuberculosis control. This short report aimed to determine the genetic diversity of M. tuberculosis isolates from an outpatient clinic in Panama City. A total of 62 M. tuberculosis isolates were genotyped by 12 loci mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) and Spoligotyping. Forty-five (72.6%) of the isolates showed unique MIRU-VNTR genotypes, and 13 (21%) of the isolates were grouped into four clusters. Four isolates showed polyclonal MIRU-VNTR genotypes. The MIRU-VNTR Hunter-Gaston discriminatory index reached 0.988. The Spoligotyping analysis revealed 16 M. tuberculosis families, including Latin American-Mediterranean, Harlem, and Beijing. These findings suggest a wide genetic diversity of M. tuberculosis isolates at one outpatient clinic. A detailed molecular epidemiology survey is now warranted, especially following second massive immigration for local Panama Canal expansion activities.Tuberculosis (TB) affects nearly 8.7 million people worldwide.1 In 2011, most TB cases were reported in Asia (59%) and Africa (26%), although cases were reported to a lesser extent in the Eastern Mediterranean Region (7.7%), the European Region (4.3%), and the Americas Region (3%). Panama stands as the country with the highest TB mortality rate in Central America.2 In 2012, more than 1,500 TB cases were reported in Panama, for an average incidence rate of 43.1 cases per 100,000 inhabitants.3 Areas located at the Pacific and Atlantic entries of the Panama Canal have harbored the highest numbers of TB cases since the Canal's construction. 4 Despite sanitation improvements in terminal port cities, recent studies have revealed elevated TB transmission as a result of a high clustering rate among multidrug-resistant TB cases. 5,6 However, data on the transmission of drug-susceptible TB within the general population remain scarce and have not been updated to reflect a second wave of immigration connected with Panama Canal expansion activities. 7Mycobacterium tuberculosis genotyping has proven to be the most important laboratory tool in understanding TB transmission. 8 In addition to studies on patient contacts; information on molecular epidemiology is useful for evaluating TB control program results. Genotyping also assists in monitoring molecular markers associated with virulence, immunogenicity, and drug resistance 9 ; among the genotyping tools available, the IS6110-restriction fragment length polymorphism (RFLP) reference standard method is based on the number of repetitions of the IS6110 sequence along the M. tuberculosis genome. 10This tool discriminates between clonally related and unrelated isolates. On the other hand, Spoligotyping focuses on detecting 43 spacer sequences in the direct repeat region of the M. tuberculosis genome. Unfortunately, the IS6110-RFLP method is a complex and laborious procedure, whereas Spoligotyping is faster and simpler but less discriminating.11,12 ...

Probable long‐term prevalence for a predominant Mycobacterium tuberculosis clone of a Beijing genotype in Colon, Panama

“…As the Beijing strain found in Colon is pansusceptible, it went unnoticed in a study carried out in Panama that focused only on multidrug-resistant (MDR) TB cases (Rosas et al, 2013). A single previous study carried out in Panama City, in which genotypic data were obtained from non-selected strains from one outpatient clinic, reported a much lower percentage (3.7%) of the Beijing lineage (Sambrano et al, 2014).…”

Simplified Model to Survey Tuberculosis Transmission in Countries Without Systematic Molecular Epidemiology Programs

“…Ours was a limited strain collection, and thus some transmission links might be missing because of the limited number of samples we were able to analyze, which covered only 1 year and 2 local settings, leading us to expect that the true figures for clustered cases are higher. In a previous study of a convenience pansusceptible M. tuberculosis strain collection from 2005 ( 18 ), only 21% (13/62) were found to be clustered. Direct comparisons between the figures from that study and our study cannot be made because of marked differences in genotyping approaches applied.…”

“…To evaluate whether our approach could simplify detection of TB transmission in countries with no systematic molecular epidemiology programs, we applied it in Panama, a country with high TB-related mortality ( 8 ). No systematic universal genotyping is available in Panama, and the only data available are from studies of cases from a single clinic and of MDR isolates ( 17 , 18 ). These studies were performed before the recent expansion of the Panama Canal, whose socio-epidemiologic effect ( 19 ) can be considered similar to that of the construction of the interoceanic railroad and the Panama Canal in the mid-19th century, when large numbers of workers from Africa, India, and China arrived in Panama.…”

“…data). The marked presence for the Beijing lineage in Colon province seems to be an emergent issue because the lineage accounted for only 3.7% of the cases in 2005 ( 18 ). Those authors raised the alert about the effect of the expansion of the Panama Canal on the likely modification of the composition of circulating strains.…”

Probable long-term prevalence for a predominant Mycobacterium tuberculosis clone of a Beijing genotype in Colon, Panama

“…Due to its key location at the isthmus between North and South America, Panama has undergone great demographic and population changes of diverse geographic origins, which has probably affected the composition of circulating MTB strains. Few and discontinuous efforts have been made to genotypically characterize MTB isolates, mainly on convenience samples (Rosas et al, 2013;Sambrano et al, 2014).…”