Patricia Gavín

Recurrent tuberculosis from 1992 to 2004 in a metropolitan area

The proportion of recurrent tuberculosis (TB) cases caused by re-infection has varied widely in previous studies. The aim of the present study was to determine the relative frequency of relapse and exogenous re-infection in patients with second episodes of TB, using DNA fingerprinting. A population-based retrospective longitudinal descriptive study was conducted in Madrid (Spain) during 1992–2004. The study consisted of 645 patients with culture-confirmed TB. Of these, 20 (3.1%) were retained because they presented with a second isolate of Mycobacterium tuberculosis. Finally, 12 of these cases were excluded because they did not complete the full treatment prescribed. All strains were typed by restriction fragment length polymorphism analysis and some by mycobacterial interspersed repetitive unit-variable number of tandem repeats analysis. The patients with recurrent TB were compared with those without recurrent TB. For seven out of the eight patients, the restriction fragment length polymorphism patterns of the Mycobacterium tuberculosis strains from the episodes of recurrent disease showed identical initial and final genotypes, indicating relapse; the remaining recurrent case showed different genotypes, suggesting exogenous re-infection. Re-infection is possible among people in developed countries, but the rates are lower than those occurring in high-risk areas. The risk factors for recurrent tuberculosis should be taken into account in the follow-up of treatment and tuberculosis control strategies.

Epidemiology of subclinical salmonellosis in wild birds from an area of high prevalence of pig salmonellosis: phenotypic and genetic profiles of Salmonella isolates.

The epidemiology of subclinical salmonellosis in wild birds in a region of high Salmonella prevalence in pigs was studied. Three hundred and seventy‐nine faecal samples from 921 birds trapped in 31 locations nearby pig premises, and 431 samples from 581 birds of 10 natural settings far from pig farms were analysed for the presence of Salmonella spp. Positive samples were serotyped and analysed for antimicrobial resistance (AR). Phage typing and pulsed‐field gel electrophoresis (PFGE) on Salmonella Typhimurium isolates were also carried out. The overall proportion of Salmonella‐positive samples was 1.85% (95% CI = 0.93, 2.77). Salmonella isolation was positively associated with samples collected from birds in the proximity of a pig operation (OR = 16.5; 95% CI = 5.17, 52.65), and from non‐migratory (or short‐distance migration) birds (OR = 7.6; 95% CI = 1.20, 48.04) and negatively related to mostly granivorous birds (OR = 0.4; 95% CI = 0.15, 1.13). Salmonella Typhimurium was the most prevalent serotype and four different XbaI PFGE patterns were observed that matched the four phage types identified (U310, U311, DT164 and DT56). Only 20% of the strains showed multi‐AR. In three farms, a high degree of homogeneity among isolates from different birds was observed. These findings suggested that pig farms may act as amplifiers of this infection among wild birds, and the degree of bird density may have much to do on this transmission. Some of the Salmonella serotypes isolated from bird faeces were of potential zoonotic transmission and associated with AR. Monitoring salmonellosis in wild bird is advised.

Conspicuous multidrug-resistant Mycobacterium tuberculosis cluster strains do not trespass country borders in Latin America and Spain.

Multidrug-resistant Mycobacterium tuberculosis strain diversity in Ibero-America was examined by comparing extant genotype collections in national or state tuberculosis networks. To this end, genotypes from over 1000 patients with multidrug-resistant tuberculosis diagnosed from 2004 through 2008 in Argentina, Brazil, Chile, Colombia, Venezuela and Spain were compared in a database constructed ad hoc. Most of the 116 clusters identified by IS6110 restriction fragment length polymorphism were small and restricted to individual countries. The three largest clusters, of 116, 49 and 25 patients, were found in Argentina and corresponded to previously documented locally-epidemic strains. Only 13 small clusters involved more than one country, altogether accounting for 41 patients, of whom 13 were, in turn, immigrants from Latin American countries different from those participating in the study (Peru, Ecuador and Bolivia). Most of these international clusters belonged either to the emerging RD(Rio) LAM lineage or to the Haarlem family of M. tuberculosis and four were further split by country when analyzed with spoligotyping and rifampin resistance-conferring mutations, suggesting that they did not represent ongoing transnational transmission events. The Beijing genotype accounted for 1.3% and 10.2% of patients with multidrug-resistant tuberculosis in Latin America and Spain, respectively, including one international cluster of two cases. In brief, Euro-American genotypes were widely predominant among multidrug-resistant M. tuberculosis strains in Ibero-America, reflecting closely their predominance in the general M. tuberculosis population in the region, and no evidence was found of acknowledged outbreak strains trespassing country borders.

Unsuspected and extensive transmission of a drug-susceptible Mycobacterium tuberculosis strain.

BackgroundA large and unsuspected tuberculosis outbreak involving 18.7% of the total of the tuberculosis cases studied, was detected in a population-based molecular epidemiological study performed in Zaragoza (Spain) from 2001 to 2004.MethodsThe Mycobacterium tuberculosis drug-susceptible strain, named MTZ strain, was genetically characterized by IS6110-RFLP, Spoligotyping and by MIRU-VNTR typing and the genetic patterns obtained were compared with those included in international databases. The characteristics of the affected patients, in an attempt to understand why the MTZ strain was so highly transmitted among the population were also analyzed.ResultsThe genetic profile of the MTZ strain was rare and not widely distributed in our area or elsewhere. The patients affected did not show any notable risk factor for TB.ConclusionThe M. tuberculosis strain MTZ, might have particular transmissibility or virulence properties, and we believe that greater focus should be placed on stopping its widespread dissemination.

Long-term molecular surveillance of multidrug-resistant tuberculosis in Spain.

The data presented here span 11 years (1998-2008) of monitoring of multidrug-resistant tuberculosis (MDR-TB) clustering through molecular typing techniques in Spain. The molecular and epidemiological data of 480 multidrug-resistant Mycobacterium tuberculosis complex isolates were analyzed. Thirty-one clusters involving 157 (32.7%) patients were identified. The proportion of immigrants increased substantially over the study period reaching 65% in 2008; however, the clustering rate remained stable indicating that local transmission was little influenced by imported MDR-TB. The three major clusters respond to the persistence of two autochthonous strains throughout the study period and an extensively drug-resistant (XDR) Mycobacterium bovis outbreak with only two cases was reported since 2002. Molecular and epidemiological evidence for the importation of new strains and their spread within the community was found. Immigrant-only clusters most often grouped patients infected abroad with strains belonging to rare spoligotypes. Conversely, widespread spoligotypes of the Latin-American and Mediterranean (LAM) and Haarlem families were responsible for the majority of the MDR-TB local transmission. The demonstration of clusters spanning several Spanish regions that have been ongoing throughout the study period makes it advisable to maintain a continuous molecular surveillance in order to monitor the spread of MDR-TB.

Rapid Test for Identification of a Highly Transmissible Mycobacterium tuberculosis Beijing Strain of Sub-Saharan Origin

ABSTRACT The development of a rapid test to identify Mycobacterium tuberculosis Beijing isolates and specifically strain GC1237, coming from a sub-Saharan country, is needed due to its alarming wide spread on Gran Canaria Island (Spain). A rapid test that detects IS6110 present between dnaA and dnaN in the Beijing strains and in a specific site for GC1237 (Rv2180c) has been developed. This test would be a useful tool in the surveillance of subsequent cases.

Multidrug-Resistant Mycobacterium tuberculosis Strain from Equatorial Guinea Detected in Spain

To the Editor: Eleven years of molecular epidemiologic data allowed the Spanish Multidrug-resistant Tuberculosis (MDR TB) Surveillance Network to identify a specific MDR Mycobacterium tuberculosis strain that had been imported into Spain from Equatorial Guinea (1). Our study brings to light the potential dissemination of this strain (named MDR-TBEG) in Equatorial Guinea, a country where little is known about the extent and features of TB or MDR TB. It also highlights that MDR strains can spread across continents, and thus MDR TB’s emergence in any country becomes a global problem. Ten MDR M. tuberculosis isolates obtained from 10 patients from Equatorial Guinea were detected in Spain during 2000 through 2008. Evidence of clonality was found within the 10 isolates because all exhibited identical genetic profiles defined by different molecular epidemiology methods (2,3) and mutations involved in drug resistance (Figure). Notably, none of the remaining 504 MDR isolates in the Spanish database matched SIT177, a spoligotype belonging to the Latin American–Mediterranean 9 (LAM9) subfamily (4). Figure Genetic profile of the multidrug-resistant tuberculosis Equatorial Guinea (MDR-TBEG) strain. RFLP, restriction fragment length polymorphism; SIT, spoligotype international type; LAM, Latin American-Mediterranean; MIRU-VNTR, mycobacterial interspersed ... The data routinely collected for all cases of MDR TB have been previously described (1). All 10 patients in the study were from Equatorial Guinea, a small African country on the Gulf of Guinea with a population of ≈500,000, an MDR TB rate >2.0% (5) of all combined (new and previously treated) TB cases, and an estimated adult HIV prevalence rate of 3.2% (www.who.int/globalatlas/predefinedReports/EFS2008/full/EFS2008_GQ.pdf). The MDR TB isolates were collected within a 9-year period (Technical Appendix): 1 in 2000, 2 in 2001, 3 in 2003, 1 in 2004, 2 in 2007, and 1 in 2008. According to their hospitals of origin, the patients were geographically dispersed in 6 different Spanish cities. We found that the interval between the patients’ arrival in Spain to the initiation of anti-TB treatment was <3 months in 6 patients, 3 of whom were clinically ill at the time of arrival. Seven patients were adult men, 2 were adult women, and 1 was an 8-year-old girl. The patients’ mean age was 30 years (range 8–54 years). Three patients were seropositive and 4 were seronegative for HIV infection (the HIV status of 3 patients was unknown). Data on prior anti-TB treatment was available for 7 case-patients, of whom only 1 had a history of antecedent TB chemotherapy. Altogether, 3 patients died before completing treatment, including 2 patients affected by miliary TB, 1 of whom was HIV-coinfected. The third patient who died was a student without a known history of immunosuppression or previous TB who had lived for 2 years in Spain. We could not establish any epidemiologic links between these patients during their stay in Spain. Analysis of drug resistance genes showed that all isolates harbored the inhA promoter mutation –15C→T (6). Alterations in the inhA gene were previously reported in 80% of the isoniazid-resistant isolates from Equatorial Guinea (5). Notably, a double mutation in the rpoB gene affecting codons 531 (Ser531Leu) and 561 (Ile561Val) was detected in the 10 MDR isolates. The presence of this uncommon mutation, Ile561Val, outside the rifampin resistance–determining region supports the hypothesis that the MDR isolates are clonal in origin. Furthermore, we demonstrated the absence of Ile561Val mutation in 3 drug-susceptible M. tuberculosis strains with an SIT177-LAM 9 spoligotype pattern, which ruled out a relationship between this spoligotype and the Ile561Val mutation. Further analysis with phylogenetic markers assigned MDR-TBEG to the principal genetic group 2, the Euro-American lineage of M. tuberculosis and its West African sublineage, on the basis of polymorphisms in codons katG463 and gyrA95, the 7-bp pks15/1 deletion, and RD174 (7,8), respectively. The analysis of the RDRio deletion confirmed that the strain belongs to the major RDRio sublineage of the LAM M. tuberculosis spoligotype family (9). This sublineage is a major cause of TB in Rio de Janeiro (Brazil) but has disseminated globally. Additional information on the geographic distribution of SIT177-LAM 9 was obtained from the updated International Spoligotyping Database (SITVIT2) of the Institut Pasteur de Guadeloupe. SITVIT2 (consulted on 23 July 2008) contained 57 isolates belonging to SIT177. Almost 50% (n = 28) came from Brazil, and 14% from Africa (Morocco, n = 6; Senegal, n = 2). The remaining isolates with known countries of origin (n = 9) were distributed in other unrelated countries. These data indicate that this particular spoligotype pattern is widely distributed. We identified 1 MDR strain of M. tuberculosis RDRio sublineage isolated in Spain from Equatorial Guinean patients. Although the transmission of MDR-TBEG in Spain could not be conclusively ruled out, the fact that MDR TB developed in most patients within 3 months after their arrival, as well as the spatiotemporal distribution of the MDR TB cases and its clonal origin, strongly suggest that MDR-TBEG was imported into Spain and that active transmission of this particular clone could be occurring in Equatorial Guinea. However, additional molecular and epidemiologic studies should be conducted in this sub-Saharan country to ascertain its role in recent transmission of MDR TB. Greater international efforts should be made to provide appropriate tools to resource-limited areas for fighting against MDR TB and preventing development of extensively drug-resistant TB.

Brote de diarrea y transmisión de Cryptosporidium hominis asociados al uso de pañal en niños

BACKGROUND AND OBJECTIVE: On the basis of several cases of cryptosporidiosis detected in a child day-care center, we stablished the extent of the outbreak and investigated causes of parasite transmission. PATIENTS AND METHOD: A retrospective cohort study was designed on all children attending day-care center and care givers to determine their infection status and identify risk factors associated to the outbreak. RESULTS: 24 cases of cryptosporidiosis were detected, with an attack rate of 0.46 (24/52); 12 of them were parasitologycally confirmed. All care givers were negative for Cryptosporidium and none of them reported symptoms of acute gastroenteritis. Transmission pattern was compatible with person to person modes. Among the factors investigated, two were associated with the risk of disease: diaper wear (relative risk = 2.06; p = 0.059); and diarrhea in relatives (relative risk = 2.05; p = 0.01). In all confirmed cases, Cryptosporidium hominis (previously known as C. parvum, genotype 1), was identified. CONCLUSIONS: Cryptosporidiosis should be considered as a possible cause of outbreaks of gastroenteritis at day-care centers. Increasing care on diaper changing practices, specially over children with diarrhea, may be the key factor to prevent transmission of Cryptosporidium.