Structural Diversity of Class 1 Integrons in Multiresistant Strains of Escherichia coli Isolated from Patients in a Hospital in Mexico City.

Since a decade, Escherichia coli has been considered an important nosocomial pathogen due to the high number of isolates multiresistant to antimicrobials reported worldwide. In clinical and environmental strains, transposons, plasmids, and integrons are currently considered the principal genetic elements responsible for the acquisition of antibiotic resistance through horizontal transfer. The objective of this research was to correlate the resistance to antibiotics of E. coli clinical strains with the presence class I integrons. In the present study, one hundred E. coli strains were isolated and tested for susceptibility and resistance to antimicrobials. Class 1 integrons were detected by PCR, and the arrangement of gene cassettes was determined by sequencing. Twenty two strains were found to carry Class 1 integrons. Sequence analysis of the variable regions revealed the presence of several gene cassettes, such as dihydrofolate reductases (dfr2d, dfrA17, and dhfrXVb), adenylyl transferases (aadA2, addA5, and addA22), and chloramphenicol efflux pump (cmlA), and oxacillinase (bla OXA-1 ). The dfrA17-addA5 arrangement prevailed upon other integrons in the study. This is the first report of the presence of the dfr2d and dhfrXVb-aadA2 cassette arrangements in a Class 1 integrons from clinical strains of E. coli. In most of the strains, it was found a direct relationship between genetic arrangements and resistance phenotypes. Four integrons were detected in plasmids that might be involved in the resistance genes transfer to other bacteria of clinical importance. Our results confirm the presence of Class 1 integrons and their essential role in the dissemination of resistance cassettes among E. coli strains.

The T1048I mutation in ATP7A gene causes an unusual Menkes disease presentation.

BACKGROUND: The ATP7A gene encodes the ATP7A protein, which is a trans-Golgi network copper transporter expressed in the brain and other organs. Mutations in this gene cause disorders of copper metabolism, such as Menkes disease. Here we describe the novel and unusual mutation (p.T1048I) in the ATP7A gene of a child with Menkes disease. The mutation affects a conserved DKTGT1048 phosphorylation motif that is involved in the catalytic activity of ATP7A. We also describe the clinical course and the response to copper treatment in this patient. CASE PRESENTATION: An 11-month-old male Caucasian infant was studied because of hypotonia, ataxia and global developmental delay. The patient presented low levels of serum copper and ceruloplasmin, and was shown to be hemizygous for the p.T1048I mutation in ATP7A. The diagnosis was confirmed when the patient was 18 months old, and treatment with copper-histidinate (Cu-His) was started immediately. The patient showed some neurological improvement and he is currently 8 years old. Because the p.T1048I mutation affects its catalytic site, we expected a complete loss of functional ATP7A and a classical Menkes disease presentation. However, the clinical course of the patient was mild, and he responded to Cu-His treatment, which suggests that this mutation leads to partial conservation of the activity of ATP7A. CONCLUSION: This case emphasizes the important correlation between genotype and phenotype in patients with Menkes disease. The prognosis in Menkes disease is associated with early detection, early initiation of treatment and with the preservation of some ATP7A activity, which is necessary for Cu-His treatment response. The description of this new mutation and the response of the patient to Cu-His treatment will contribute to the growing body of knowledge about treatment response in Menkes disease.

Clonal dispersion of Acinetobacter baumannii in an intensive care unit designed to patients COVID-19.

INTRODUCTION: SARS-CoV2 pandemic marks the need to pay attention to bacterial pathogens that can complicate the hospital stay of patients in the intensive care unit (ICU). ESKAPE bacteria which includes Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae are considered the most important, because of their close relationship with the development of ventilator-associated pneumonia (VAP). The aim of this work was to identify and characterize ESKAPE bacteria and to detect their possible clonal spread in medical devices, patients, and medical personnel of the ICU for COVID-19 patients of the Hospital Juarez de Mexico. METHODOLOGY: Genetic identification of ESKAPE bacteria was performed by analyzing the 16S rRNA gene. Resistance assays were performed according to the CLSI guidelines. Assembly of AdeABCRS operon and inhibition assays of pumps efflux in Acinetobacter baumannii isolates were performed. Associated gene involved in biofilm formation (icaA) was performed in isolates belonging to the Staphylococcus genus. Finally, typing by ERIC-PCR and characterization of mobile genetic element SCCmec were done. RESULTS: Heterogeneous distribution of ESKAPE and non-ESKAPE bacteria was detected in various medical devices, patients, and medical personnel. Acinetobacter baumannii and Staphylococcus aureus were the predominant ESKAPE members. The analysis of intergenic regions revealed an important clonal distribution of A. baumannii (AdeABCRS+). Genotyping of SCCmec mobile genetic elements and the icaA gene showed that there is no clonal distribution of S. aureus. CONCLUSIONS: Clonal spread of A. baumannii (AdeABCRS+) highlights the importance of adopting good practices for equipment disinfection, surfaces and management of COVID-19 patients.

Genetic and phenotypic determinants of resistance to antibiotics in Aeromonas spp., strains isolated from pediatric patients.

INTRODUCTION: Intestinal and extraintestinal infections by Aeromonas spp., remain controversial, due to the existence of healthy carriers of Aeromonas spp. In children under five years old, the diarrhea of infectious origin constitutes the second cause of mortality and remains a major concern for public health. The aim of this work was to detect the pheno/genotype of ß-lactamases and class 1 integrons in Aeromonas spp., strains isolated from pediatric patients in a tertiary referral hospital in Mexico. METHODOLOGY: Sixty-six strains of Aeromonas spp., were isolated from clinical samples of pediatric origin and were identified by RFLP-PCR 16S rRNA. Resistance phenotype according to CLSI, genetic and phenotypic detection of extended-spectrum ß-lactamases (ESBL) and metallo-b-lactamases (MBL) was performed. Finally, characterization of class 1 integrons was performed. RESULTS: Aeromonas spp., strains of diarrheic origin were more predominant. A wide heterogeneity was detected, where A. caviae was the predominant specie. Second-generation cephalosporins, fluoroquinolones, and nitrofurans had best antimicrobial activity; moreover, antibiotics of the ß-lactamic and lincosamides families showed lower inhibitory activity. Phenotypically, prevalences of 4.55% and 3.03% were detected for MBL (intestinal origin) and ESBL (extraintestinal origin), respectively. blaIMIS-cphA and blaTEM-1 genes, and nineteen class 1 integrons carrying two variants of cassettes corresponding to adenylyl transferases (aadA), and dihydrofolate reductases (dfrA). Monogenic array with aadA1 cassette was predominantly. CONCLUSIONS: ESBL and class 1 integrons, in Aeromonas collected from pediatric patients, determines a major detection challenge for the clinical microbiology laboratory and represents a remarkable epidemiological risk of nosocomial spread of multidrug-resistant determinants.

Commensal and virulent Escherichia coli strains of vaginal origin are reservoirs of resistance cassettes in class 1 integrons.

INTRODUCTION: Antimicrobial resistance in Escherichia coli, one of the causal agents of aerobic vaginitis, leads to the persistence of the infection. The investigation of integrons acquires relevance, since they are elements that are responsible for the acquisition of resistance to antibiotics. The aim of this work was to describe the structural diversity of class 1 integrons in virulent and commensal strains of E. coli isolated from patients with vaginal infection. METHODOLOGY: Ninety-two strains of E. coli were isolated from patients with aerobic vaginitis. Resistance profile against 19 antibiotics and class 1 integrons were detected by PCR. The identity and arrangement of cassettes was determined by sequencing. ERIC-PCR assays were carried out in strains with identical arrays. Finally, genotyping by Clermont algorithm and serotyping were performed. Seventeen strains showed integrons located in plasmids. RESULTS: Ten different gene cassette arrays were identified in 30 strains of E. coli. Cassettes corresponding to genes coding for adenylyltransferases (aadA), dihydrofolate reductases (dfrA), and oxacillinases (blaOXA) were detected. Array dfrA17-aadA5 was predominantly prevalent over the other arrays identified. Phylogenetic group A was the most predominant, followed by group B2 and D. CONCLUSIONS: This study demonstrates the presence of E. coli of vaginal origin carrying class 1 integrons, which are main genetic elements of capture of resistance genes, with the possibility of capturing new resistance cassettes. These evidences should serve for the modification of protocols in the diagnosis and treatment of aerobic vaginitis, and the development of policies for the rational use of antimicrobials.

Morbidity Trends and Risk of Tuberculosis: Mexico 2007-2017.

Background: To know the current status of the epidemiological and geographic distribution of tuberculosis and its complication meningeal tuberculosis in Mexico, this work analyzes national surveillance data (ten years) issued by the General Directorate of Epidemiology (GDE). Methods: An observational and retrospective analysis of monthly and annual reports of pulmonary and meningeal tuberculosis cases from January 2007 to December 2017 was performed on the annual reports issued by the GDE in Mexico. The number of cases and incidence were classified by year, state, age group, gender, and seasons. Results: A national case distribution map of pulmonary and meningeal tuberculosis incidence was generated. During this period, a total of 184,003 and 3,388 cases were reported with a median of 16,727.5 and 308 cases per year for pulmonary and meningeal tuberculosis diseases, respectively. The number of cases and incidence of pulmonary and meningeal tuberculosis per year showed that male gender presented a continuous increase in both parameters. The geographic analysis of the distribution of cases of tuberculosis showed that states like Guerrero, Tabasco, and Veracruz presented higher means of tuberculosis cases during this period. Northern states had the highest number of cases in the country compared to other states. In Mexico, pulmonary tuberculosis and meningeal tuberculosis are seasonal. Interestingly, cases of meningeal tuberculosis show an increase during October and November (autumn). Conclusions: In Mexico, during the years 2007-2017, there has been an increase in the proportion of male TB patients. It remains necessary to implement strategies to detect TB in the adult population, especially among men, because tuberculosis could be difficult to recognize in an early stage in the population, and the appearance of resistant strains can cause an increase in the incidence of the disease.

Changes in the incidence of intestinal giardiosis in Mexican population during five years (2011-2015).

Giardiosis is a parasitic disease caused by the protozoan Giardia intestinalis, which is distributed worldwide. Most of the data on the prevalence of giardiosis in Mexico comes from research, but it is also necessary to study the data provided by the Mexican Health Ministry and issued by the General Directorate of Epidemiology. The aim of this work was analyse the national surveillance data for human giardiosis in order to update the epidemiological data of this disease in Mexico. A retrospective observational analysis of giardiosis (from January 2011 to December 2015) was performed in the annual reports emitted by the GDE in Mexico. The cases were classified by year, state, age group, gender and seasons of the year. During the period of 2011-2015, a reduction of 38.51% was observed in the total number of new cases of giardiosis reported in the whole country The states of Sinaloa, Yucatan, and Chiapas presented the highest number of new cases reported during the analysed period. Giardiosis rates were always higher among women in all age groups, but the maximum incidence was observed in both sexes in the age group of 1-4 years old (the most susceptible group). On the other hand, the number of cases increased dramatically in southern states during warmer months. Giardiosis is influenced by ambient temperature changes along the year, although this study suggests that tends to decrease in all the analysed states and could be related to the overall improvement of hygienic practices within the Mexican population.