Vibrio parahaemolyticus Is Associated with Diarrhea Cases in Mexico, with a Dominance of Pandemic O3:K6 Clones.

In the present study, we conducted surveillance of the V. parahaemolyticus strains present in clinical samples from six geographical regions of Mexico (22 states) from 2004 to 2011. The serotype dominance, virulence genes, presence of pandemic O3:K6 strains, and antibiotic resistance of the isolates were investigated. In total, 144 strains were isolated from the clinical samples. Seven different O serogroups and twenty-five serovars were identified. Most clinical isolates (66%, 95/144) belonged to the pandemic clone O3:K6 (tdh+, toxRS/new+ and/or orf8+) and were detected in 20 of the 22 states. Among the pandemic clones, approximately 17.8% (17/95) of the strains cross-reacted with the antisera for the K6 and K59 antigens (O3:K6, K59 serotype). Other pathogenic strains (tdh+ and/or trh+, toxRS/new-, orf8-) accounted for 26.3%, and the nonpathogenic strains (tdh- and/or trh-) accounted for 7.6%. Antimicrobial susceptibility testing showed that most of the strains were resistant to ampicillin (99.3%) but were sensitive to most tested antibiotics. The level of multidrug resistance was 1.3%. Our results indicate that pandemic O3:K6 is present in most Mexican states, thus, constant surveillance of V. parahaemolyticus strains in diarrhea patients is a public health priority and is useful for conducting risk assessments of foodborne illnesses to prevent V. parahaemolyticus outbreaks. Overall, our observations indicate that the pandemic O3:K6 clone of V. parahaemolyticus has become a relatively stable subpopulation and may be endemically established in Mexico; therefore, constant surveillance is needed to avoid new outbreaks of this pathogen.

The genetics of recurrent hydatidiform moles in Mexico: further evidence of a strong founder effect for one mutation in NLRP7 and its widespread.

PURPOSE: To investigate the frequency of a founder mutation in NLRP7, L750V, in independent cohorts of Mexican patients with recurrent hydatidiform moles (RHMs). METHODS: Mutation analysis was performed by Sanger sequencing on DNA from 44 unrelated Mexican patients with RHMs and seven molar tissues from seven additional unrelated patients. RESULTS: L750V was present in homozygous or heterozygous state in 37 (86%) patients and was transmitted on the same haplotype to patients from different states of Mexico. We also identified a second founder mutation, c.2810+2T>G in eight (18.1%) patients, and a novel premature stop-codon mutation W653*. CONCLUSION: Our data confirm the strong founder effect for L750V, which appears to be the most common mutation in NLRP7. We also report on six healthy live births to five patients with biallelic NLRP7 mutations, two from spontaneous conceptions and four from donated ovum and discuss our recommendations for DNA testing and genetic counseling.

Causal analysis of fetal death in high-risk pregnancies.

OBJECTIVES: To determine the causes of fetal death among the stillbirths using two classification systems from 22 weeks of gestation in a period of three years in high-risk pregnancies. This is a retrospective observational study. METHODS: The National Institute of Perinatal Health in Mexico City is a Level 3 care referral center attending high-risk pregnancies from throughout the country. The population consisted of patients with fetal death during a three-year period. Between January 2016 and December 2018, all stillbirths were examined in the Pathology Department by a pathologist and a medical geneticist. Stillbirth was defined as a fetal death occurring after 22 weeks of gestation. RESULTS: Main outcome measures: Causal analysis of fetal death using the International Statistical Classification of Disease and Related Health Problems-Perinatal Mortality (ICD-PM) and initial causes of fetal death (INCODE) classification systems. A total of 297 stillborn neonates were studied. The distribution of gestational age in antepartum stillbirths (55.2%) showed a bimodal curve, 36% occurred between 24 and 27 weeks and 32% between 32 and 36 weeks. In comparison, the majority (86%) of intrapartum deaths (44.8%) were less than 28 weeks of gestation. Of the 273 women enrolled, 93 (34%) consented to a complete fetal autopsy. The INCODE system showed a present cause in 42%, a possible cause in 54% and a probable cause in 93% of patients. CONCLUSIONS: The principal causes of antepartum death were fetal abnormalities and pathologic placental conditions and the principal causes of intrapartum death were complications of pregnancy which caused a premature labor and infections.

Evaluation of serological diagnostic tests of human brucellosis for prevention and control in Mexico.

Brucellosis is a zoonosis mainly present in developing countries. The WHO reports 500,000 new cases every year. From 2012 to 2016, 13,677 cases were reported in Mexico, with 2.00 to 2.64 rate per 100,000 inhabitants. To analyze the diagnostic algorithm of brucellosis in Mexico, we compared the commercial laboratory tests ELISA, Brucellacapt®, and lateral flow test (LFT) in a study of 473 individuals from two endemic Mexican populations. All patients were treated in first-level medical units for presenting brucellosis compatible symptoms and without a history of the disease. Clinical-epidemiological information was gathered and initial serum samples were obtained to react with anti-Brucella antibodies; subsequent samples were collected at follow-up treatment visits. Using the Rose Bengal screening, we found 165 negative samples and 308 positive reactive samples, of which 222 cases were confirmed and 234 were positive on at least one marker (IgG or IgM) or LFT. When Brucellacapt® was used, similar results to those observed with the conventional algorithm were found as judged by the Cohen's kappa coefficient (κ) (0.813, 95% CI 0.7788-0.8472). Similar κ indices between conventional algorithm and ELISA pair were found, 0.7038 (95% CI 0.6555-0.7521), representing high similarity between both groups of diagnosis. We conclude that conventional serodiagnoses, Brucellacapt® and LFT, presented inconclusive results and poor correlation between them. By contrast, ELISA test pair (IgG + IgM) presented high correlation with the conventional algorithm and greater capacity for correct positive and negative classification.

Biochemical and full genome sequence analyses of clinical Vibrio cholerae isolates in Mexico reveals the presence of novel V. cholerae strains.

The first week of September 2013, the National Epidemiological Surveillance System identified two cases of cholera in Mexico City. The cultures of both samples were confirmed as Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Initial analyses by PFGE and by PCR-amplification of the virulence genes, suggested that both strains were similar, but different from those previously reported in Mexico. The following week, four more cases were identified in a community in the state of Hidalgo, located 121 km northeast of Mexico City. Thereafter a cholera outbreak started in the region of La Huasteca. Genomic analyses of the four strains obtained in this study confirmed the presence of Pathogenicity Islands VPI-1 and -2, VSP-1 and -2, and of the integrative element SXT. The genomic structure of the 4 isolates was similar to that of V. cholerae strain 2010 EL-1786, identified during the epidemic in Haiti in 2010.

Genome Sequence of Vibrio cholerae Strain O1 Ogawa El Tor, Isolated in Mexico, 2013.

We present the draft genome sequence of Vibrio cholerae InDRE 3140 recovered in 2013 during a cholera outbreak in Mexico. The genome showed the Vibrio 7th pandemic islands VSP1 and VSP2, the pathogenic islands VPI-1 and VPI-2, the integrative and conjugative element SXT/R391 (ICE-SXT), and both prophages CTXφ and RS1φ.

Outbreak of Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor strain--La Huasteca Region, Mexico, 2013.

On September 2 and 6, 2013, Mexico's National System of Epidemiological Surveillance identified two cases of cholera in Mexico City. Rectal swab cultures from both patients were confirmed as toxigenic Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Pulsed-field gel electrophoresis and virulence gene amplification (ctxA, ctxB, zot, and ace) demonstrated that the strains were identical to one another but different from strains circulating in Mexico previously. The strains were indistinguishable from the strain that has caused outbreaks in Haiti, the Dominican Republic, and Cuba. The strain was susceptible to doxycycline, had intermediate susceptibility to ampicillin and chloramphenicol, was less than fully susceptible to ciprofloxacin, and was resistant to furazolidone and trimethoprim-sulfamethoxazole. An investigation failed to identify a common source of infection, additional cases, or any epidemiologic link between the cases. Both patients were treated with a single, 300-mg dose of doxycycline, and their symptoms resolved.

Laboratory-based surveillance of Streptococcus pneumoniae invasive disease in children in 10 Latin American countries: a SIREVA II project, 2000-2005.

BACKGROUND: For the last 14 years the Pan American Health Organization has been promoting surveillance of invasive pneumococcal disease in Latin American children for better understanding of the disease tendencies regarding capsular types circulation in each country and susceptibility to antimicrobials. METHODS: Laboratory-based surveillance data from 10 Latin American countries collected from 2000 to 2005 were analyzed, including serotype distribution and susceptibility to beta-lactam antibiotics. RESULTS: Although 61 different capsular types were identified during the 6-year surveillance, 13 serotypes accounted for 86% of all isolates. These were consistently the most prevalent throughout the study period with serotype 14 predominating. Diminished susceptibility to penicillin was detected in 38% of all Streptococcus pneumoniae isolates, with the highest prevalence in Dominican Republic and Mexico. Decreased susceptibility to penicillin increased in Brazil and Colombia whereas decreased high resistance rates was recorded in Chile. CONCLUSIONS: These data indicate that 10 countries of the Region continue to have high quality laboratory-based surveillance for pneumococcal disease thus generating valuable information so that healthcare decision makers may prioritize interventions. The heptavalent vaccine will potentially cover from 52.4% to 76.5% of strains causing invasive pneumococcal disease and the 13 valent from 76.7% to 88.3%.

Infectious diseases in Mexico. A survey from 1995-2000.

Data obtained at a central laboratory for emerging, re-emerging, and other infectious diseases in Mexico from 1995-2000 are presented. An outstanding increase of DEN-3 circulation was identified. Aedes aegypti, the dengue vector, is widely distributed. Leptospirosis has become the most important differential diagnosis for dengue. Identification of rabies virus variants allowed cataloging of new transmitters of rabies. Rotavirus showed a clear seasonal distribution, while different proportions of pathogenic classes of Escherichia coli under endemic and outbreak conditions were seen. Serotypes of several bacteria are reported as well as the sources of isolation and frequency of Shigella, Salmonella, and Vibrio cholerae. Rise and disappearance of cholera could be followed along the past decade. Influenza strains were identified, as were several pathogens causing sexually transmitted infections. Laboratory support was important for surveillance after Hurricane Mitch. Multidrug-resistant strains of Mycobacterium tuberculosis are emerging and primary resistance is very high. It is now mandatory to search for antibodies to Trypanosoma cruzi in blood banks. Triatoma barberi, a peridomestic bug, is the main vector of Chagas disease. Localized cutaneous leishmaniosis increased in regions having a guerrilla element in Chiapas. Modern immunodiagnostic techniques are used for control studies of cysticercosis and similar techniques were recently standardized for Trichinella spiralis detection. Low iodine values in children's urine were found in several Mexican states; therefore, use of iodized salt should be encouraged.

Manual de procedimientos de laboratorio INDRE/SAGAR: brucelosis / Labotatory procedures manual INDRE/SAGAR: brucelosis

Dirigido al personal de salud que trabaje en laboratorios, el presente manual fue elaborado con el propósito de mostrar los procedimientos para el diagnóstico de brucelosis, tanto en humanos como en animales, así como medidas de biosegurdiad en el laboratorio. El documento se divide en: 1. Introducción 2. Generalidades 3. Diagnóstico de laboratorio 4. Muestras para métodos directos de diagnóstico 5. Cultivo de brucelas 6. Identificación de especies de brucella 7. Métodos indirectos de diagnóstico 8. Apéndice 9. Referencias