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Introduction: Gastrointestinal diseases due to infectious pathogens currently represent an important global health concern, especially in children and developing countries. Early and accurate detection of gastrointestinal pathogens is important to initiate the appropriate type of therapy. Multiplex molecular gastrointestinal panels rapidly detect several gastrointestinal pathogens at once with high sensitivity.Areas covered: We assess the scope and limitations of several multiplex gastrointestinal panels approved by the Food and Drug Administration or marked by Conformite Europeenne-in vitro diagnostic. We compare 10 syndromic gastrointestinal panels, 14 bacteria-specific multiplex panels, seven parasite-specific multiplex panels, and eight virus-specific multiplex panels.Expert opinion: Thanks to the advances made in the diagnostic approaches for gastrointestinal infections, there are various panels to choose. The choice of a specific syndromic gastrointestinal multiplex panel should be made to improve patient care. Diagnostic syndromic multiplex approaches for gastrointestinal infections should be customized; each hospital should develop its diagnostic algorithm for gastrointestinal infections tailored to its setting, study population, and geographical site. Current multiplex gastrointestinal panels could be improved by including the detection of antimicrobial resistance, toxigenic Clostridioides difficile, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the virus responsible for the COVID-19 pandemic).

Objectives Linezolid is a synthetic oxazolidinone antibiotic frequently used to treat vancomycin-resistant enterococcal infections. Vancomycin-susceptible Enterococcus faecalis can develop resistance to linezolid in environments with excessive linezolid use. The aim of this study was to define risk factors and outcome associated with the acquisition of linezolid-resistant E. faecalis (LREfs). Methods A retrospective case–control study was designed including patients hospitalised from January 2014 to October 2017 at Hospital Civil de Guadalajara ‘Fray Antonio Alcalde’ in Guadalajara, Mexico. A total of 50 patients culture-positive for LREfs and 100 control patients hospitalised in the same room and time as the cases were included. Clinical and demographic data were collected and analysed. Results Risk factors for the presence of LREfs included prior linezolid use [odds ratio (OR) = 6.74], prior clindamycin use (OR = 6.72) and previous surgery (OR = 5.79). The mortality rate was 18% for LREfs cases versus 9% for controls. Conclusion LREfs has emerged and spread in our hospital, an environment in which linezolid use is considerable. Risk factors for LREfs are prior antibiotic use, including linezolid, and previous surgery.

Coagulase-negative Staphylococcus hominis causes bloodstream infections and often can form biofilms on medical devices. This study aimed to improve the current methodology for antimicrobial susceptibility testing (AST) in biofilm-growing S. hominis isolates. Biofilm production of S. hominis was assessed using the crystal violet staining method in trypticase soy broth supplemented with 1% glucose (TSB

Accurate recognition of the closely related species Klebsiella pneumoniae, Klebsiella quasipneumoniae and Klebsiella variicola by phenotypic, biochemical and automated tests is notoriously unreliable in hospitals' diagnostic laboratories. A comparative genomics approach was conducted for the correct differentiation of the main bacterial species in the K. pneumoniae complex. Analysis of the deduced proteomes of 87 unique genomes of the Klebsiella in public databases, was used for the identification of unique protein family members. This allowed the design of a multiplex-PCR assay for the correct differentiation of these three species from different origins. This system allowed us to determine the prevalence of K. pneumoniae, K. quasipneumoniae and K. variicola among a collection of 552 clinical isolates. Of these, 87.3% (482/552) isolates corresponded to K. pneumoniae, 6.7% (33/552) to K. quasipneumoniae and 5.9% (33/552) to K. variicola. The multiplex-PCR results showed a 100% accuracy for the correct identification of the three species evaluated, which was validated with rpoB phylogenetic sequence analysis.

Staphylococcus hominis is a coagulase-negative opportunistic pathogen responsible for implanted medical device infections. Rapid identification and virulence factors detection are crucial for appropriate antimicrobial therapy. We aimed to search protein biomarker peaks for rapid classification of antibiotic resistance and subspecies of S. hominis using MALDI-TOF MS.S. hominis clinical isolates (n = 148) were screened for subspecies differentiation by novobiocin resistance. Biofilm composition and formation were determined by detachment assay and crystal violet staining, respectively. Antibiotic susceptibility was performed by the broth microdilution method. The search for potential biomarkers peaks was enabled by ClinProTools 3.0, flexAnalysis 3.4, and Biotools 3.2 for statistical analysis, peak visualization, and protein/peptide alignment, respectively.Of 148 isolates, 12.16% were classified as S. hominis subsp. novobiosepticus, 77.77% were biofilm producers, and ˃ 50% were multidrug-resistant. Two potential biomarker peaks, 8975 m/z and 9035 m/z were detected for the discrimination of methicillin resistance with a sensitivity of 96.72%. The following peaks were detected for subspecies differentiation: 2582 m/z, 2823 m/z, and 2619 m/z with 88.89-98.28% of sensitivity.We found potential biomarker peaks to predict methicillin resistance and discriminate S. hominis subspecies during routine MALDI-TOF MS identification in a clinical setting to enable better antibiotic treatment.

Rapid identification and characterisation of drug-resistant bacterial pathogens have an important role in diagnostic and antimicrobial stewardship. Response time in the diagnosis of not only the etiological agent but also in antimicrobial susceptibility results is of utmost importance in patient treatment. In this study, matrix-assisted laser desorption ionisation–time of flight (MALDI-TOF) mass spectrometry (MS) was used to screen for biomarkers of ESCAPE (vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus, hypervirulent NAP1/ribotype 027 Clostridioides [Clostridium] difficile, multidrug resistant Acinetobacter baumannii, multidrug resistant Pseudomonas aeruginosa, and carbapenem-resistant Enterobacteriaceae) pathogens to predict antimicrobial resistance or hypervirulence. Several biomarkers of drug-resistant genotypes in S. aureus, A. baumannii, P. aeruginosa, and K. pneumoniae, as well as hypervirulence in C. difficile, were detected. The fastest possible susceptibility testing with MALDI-TOF MS is simultaneous detection of a characteristic drug-resistant peak and species identification in the same spectra generated in routine processing. According to our approach, resistance or virulence biomarker peaks can be identified while performing routine microbiology analysis, and no additional assays nor prolonged incubation time is needed. Outstanding biomarker peaks detected in our study should be further analysed by additional methods to identify the specific proteins involved.

Introduction: Infections caused by the opportunistic Stenotrophomonas maltophilia pathogen in immunocompromised patients are complicated to treat due to antibiotic resistance and the ability of the bacteria to produce biofilm.Areas covered: A MEDLINE/PubMed search was performed of available literature to describe the role of biofilm produced by S. maltophilia in the diseases it causes, including biofilm-influencing factors, the biofilm forming process and composition. The antimicrobial resistance due to S. maltophilia biofilm production and current antibiofilm strategies is also included.Expert opinion: Through the production of biofilm, S. maltophilia strains can easily adhere to the surfaces in hospital settings and aid in its transmission. The biofilm can also cause antibiotic tolerance rendering some of the therapeutic options ineffective, causing setbacks in the selection of an appropriate treatment. Conventional susceptibility tests do not yet offer therapeutic guidelines to treat biofilm-associated infections. Current S. maltophilia biofilm control strategies include natural and synthetic compounds, chelating agents, and commonly prescribed antibiotics. As biofilm age and matrix composition affect the level of antibiotic tolerance, their characterization should be included in biofilm susceptibility testing, in addition to molecular and proteomic analyzes. As for now, several commonly recommended antibiotics can be used to treat biofilm-related S. maltophilia infections.

This work describes the molecular characteristics and the genetic structure of plasmid-borne NDM-1 gene of 5 different bacterial species associated with nosocomial infections in Mexico. In Acinetobacter spp. the NDM-1 gene structure is conserved, suggesting an intraspecies spread. In Enterobacteriaceae, a dissemination of IncFII-related plasmid encoding the NDM-1 suggests horizontal transfer, but E. coli showed a different molecular mechanism, related to class 1 integron and ISCR1 element.

Background This study aimed to determine the epidemiological, microbiological, and molecular characteristics of an outbreak of carbapenem-resistant Leclercia adecarboxylata in three hospitals associated with the unintended use of contaminated total parental nutrition (TPN). Methods For 10 days, 25 patients who received intravenous TPN from the same batch of a formula developed sepsis and had blood cultures positive for L. adecarboxylata. Antimicrobial susceptibility and carbapenemase production were performed in 31 isolates, including one from an unopened bottle of TPN. Carbapenemase-encoding genes, extended-spectrum β-lactamase–encoding genes were screened by PCR, and plasmid profiles were determined. Horizontal transfer of carbapenem resistance was performed by solid mating. Clonal diversity was performed by pulsed-field gel electrophoresis. The resistome was explored by whole-genome sequencing on two selected strains, and comparative genomics was performed using Roary. Results All 31 isolates were resistant to aztreonam, cephalosporins, carbapenems, trimethoprim/sulfamethoxazole, and susceptible to gentamicin, tetracycline, and colistin. Lower susceptibility to levofloxacin (51.6%) and ciprofloxacin (22.6%) was observed. All the isolates were carbapenemase producers and positive for blaNDM-1, blaTEM-1B, and blaSHV-12 genes. One main lineage was detected (clone A, 83.9%; A1, 12.9%; A2, 3.2%). The blaNDM-1 gene is embedded in a Tn125-like element. Genome analysis showed genes encoding resistance for aminoglycosides, quinolones, trimethoprim, colistin, phenicols, and sulphonamides and the presence of IncFII (Yp), IncHI2, and IncHI2A incompatibility groups. Comparative genomics showed a major phylogenetic relationship among L. adecarboxylata I1 and USDA-ARS-USMARC-60222 genomes, followed by our two selected strains. Conclusion We present epidemiological, microbiological, and molecular evidence of an outbreak of carbapenem-resistant L. adecarboxylata in three hospitals in western Mexico associated with the use of contaminated TPN.

Aim This report presents phenotypic and genetic data on the prevalence and characteristics of extended-spectrum β-lactamases (ESBLs) and representative carbapenemases-producing Gram-negative species in Mexico. Material and methods A total of 52 centers participated, 43 hospital-based laboratories and 9 external laboratories. The distribution of antimicrobial resistance data for Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae complex, Acinetobacter baumannii complex, and Pseudomonas aeruginosa in selected clinical specimens from January 1 to March 31, 2020 was analyzed using the WHONET 5.6 platform. The following clinical isolates recovered from selected specimens were included: carbapenem-resistant Enterobacteriaceae, ESBL or carbapenem-resistant E. coli, and K. pneumoniae, carbapenem-resistant A. baumannii complex, and P. aeruginosa. Strains were genotyped to detect ESBL and/or carbapenemase-encoding genes. Results Among blood isolates, A. baumannii complex showed more than 68% resistance for all antibiotics tested, and among Enterobacteria, E. cloacae complex showed higher resistance to carbapenems. A. baumannii complex showed a higher resistance pattern for respiratory specimens, with only amikacin having a resistance lower than 70%. Among K. pneumoniae isolates, blaTEM, blaSHV, and blaCTX were detected in 68.79%, 72.3%, and 91.9% of isolates, respectively. Among E. coli isolates, blaTEM, blaSHV, and blaCTX were detected in 20.8%, 4.53%, and 85.7% isolates, respectively. For both species, the most frequent genotype was blaCTX-M-15. Among Enterobacteriaceae, the most frequently detected carbapenemase-encoding gene was blaNDM-1 (81.5%), followed by blaOXA-232 (14.8%) and blaoxa-181(7.4%), in A. baumannii was blaOXA-24 (76%) and in P. aeruginosa, was blaIMP (25.3%), followed by blaGES and blaVIM (13.1% each). Conclusion Our study reports that NDM-1 is the most frequent carbapenemase-encoding gene in Mexico in Enterobacteriaceae with the circulation of the oxacillinase genes 181 and 232. KPC, in contrast to other countries in Latin America and the USA, is a rare occurrence. Additionally, a high circulation of ESBL blaCTX-M-15 exists in both E. coli and K. pneumoniae.

In this study, we compared the observed agreement and correlation of the Vitek 2 system with the biomarker-based MALDI-TOF MS identification results of bacteria and yeast on a routine basis.Clinical isolates collected from two years were included. Isolates were identified using the Vitek 2 system and MALDI-TOF MS. The percent of observed agreements and the kappa coefficient (κ) with its corresponding 95% interval confidence were calculated between both results. When species-level biotyper identifications matched a member of a group, complex, or one of the species of a slashing call, the identification was considered correct for agreement calculations.The 4,238 recruited isolates included 2,669 gram-negative bacteria, 1,479 gram-positive bacteria, and 90 yeast. Among gram-negative bacteria, the most frequent species identified wereAccording to our results, when antimicrobial susceptibility tests are performed using Vitek 2 cards, the most common pathogens are correctly identified for the most frequent clinical isolates.

Background: Surveillance of antimicrobial resistance (AMR) requires an international approach with national and local strategies. Our aim was to summarize a retrospective 10-year report of antibiot...

Stenotrophomonas maltophilia is a Gram-negative drug-resistant pathogen responsible for healthcare-associated infections. The aim was to search for biomarker peaks that could rapidly detect biofilm production in S. maltophilia clinical isolates obtained from two tertiary care hospitals in Mexico. Isolates were screened for the presence of biofilm-associated genes, in which the fsnR gene was associated with biofilm production (p = 0.047), whereas the rmlA+ genotype was associated with the rpfF- genotype (p = 0.017). Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectra comparison yielded three potential biomarker peaks (4661, 6074, and 6102 m/z) of biofilm-producing rmlA+ and rpfF- genotypes with >90% sensitivity (pfnsR, rmlA and rpfF-2 genes, suggested to play a role in biofilm formation. Isolates obtained in the intensive care unit showed low clonality, suggesting no transmission within the hospital ward. The detection of biomarkers peaks by MALDI-TOF MS could potentially be used to early recognize and discriminate biofilm-producing S. maltophilia strains and aid in establishing appropriate antibiotic therapy.

The aim was to evaluate the antimicrobial activity of essential oils-derived volatile compounds against nosocomial pathogens, including representative multidrug-resistant (MDR) Acinetobacter baumannii clinical isolates. Minimum inhibitory dose (MID) values for the compounds were determined by the gaseous contact assay. A. baumannii representative clones were selected by pulsed-field gel electrophoresis. MDR profiles were determined by microdilution assay. Drug-resistant genes were detected by PCR. Biofilm production was determined by the crystal violet method. From all tested compounds, carvacrol had markedly lower MIDs (3.89–48.8 mg/L) against A. baumannii than against the other nosocomial MDR pathogens. The lowest MID was detected against three strains, which were obtained from different specimen types, had high drug resistance profiles and showed variable biofilm production. The work herein provides evidence that carvacrol may have therapeutic potential as a treatment for MDR A. baumannii infec...

Purpose. Stenotrophomonas maltophilia is a multidrug-resistant opportunistic pathogen causing an increasing number of nosocomial infections. Our aim was to evaluate the risk factors and mechanisms associated with trimethoprim–sulfamethoxazole (SXT) resistance in S. maltophilia infections in Mexico. Methodology. Clinical isolates and patients' demographic and clinical data were collected from February 2007 to August 2015 in two tertiary-care hospitals in Mexico. Antimicrobial susceptibility and analysis of sul and SmeABC and SmeDEF efflux pump overexpression were performed in all isolates. Results/Key findings. In the 9-year period, 196 patients infected with S. maltophilia were identified. Most patients were male, and the mean age was 46.2 years. The mean Charlson score was 1.42, and the most frequent comorbidities were arterial hypertension (26.7 %), type 2 diabetes (21.2 %) and cerebral infarction (11.6 %). High drug resistance to meropenem (93.4 %), gentamicin (55.1 %), ceftazidime (52.3 %), cefotaxime (51.5 %), amikacin (42.3 %) and cefepime (32.1 %), and lower resistance to ciprofloxacin (26.0 %), SXT (25.0 %), chloramphenicol (14.3 %) and levofloxacin (2.6 %) were detected. SXT resistance was not associated with the sul genes. SmeABC overexpression was associated with gentamicin (P=0.001) and levofloxacin resistance (P=0.041), whereas SmeDEF overexpression was associated with ceftazidime resistance (P=0.003). Prolonged hospitalization (≥15 days) was an independent risk factor for SXT-resistant S. maltophilia infections (OR=3.05; 95 % CI=1.12–8.86; P=0.029). Conclusion. Given the high SXT resistance rate, SXT is not an effective first-line therapy for our patients; instead, levofloxacin could be used as an appropriate therapeutic option against S. maltophilia infections.

Herein, we report the draft-genome sequences and annotation of two opportunistic pathogenic strains of Staphylococcus cohnii isolated from humans. One strain (SC-57) was isolated from blood from a male patient in May 2006 and the other (SC-532) from a catheter from a male patient in June 2006. Similar to other genomes of Staphylococcus species, most genes (42%) of both strains are involved in metabolism of amino acids and derivatives, carbohydrates and proteins. Eighty (4%) genes are involved in virulence, disease, and defense and both species show phenotypic low biofilm production and evidence of increased antibiotic resistance associated to biofilm production. From both isolates, a new Staphylococcal Cassette Chromosome mec was detected: mec class A, ccr type 1. This is the first report of whole genome sequences of opportunistic S. cohnii isolated from human patients. Electronic supplementary material The online version of this article (10.1186/s40793-017-0263-1) contains supplementary material, which is available to authorized users.

Patient: Male, 32 Final Diagnosis: NDM-1-producing Klebsiella pneumoniae • bacteremia Symptoms: Fever Medication: — Clinical Procedure: None Specialty: Infectious Diseases Objective: Diagnostic/therapeutic accidents Background: Infections affecting burn patients are frequently caused by Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacteriaceae species. Infections with these pathogens have become increasingly difficult to treat due to evolving antibiotic resistance mechanisms, including the production of carbapenemases. Case Report: The present case report describes the evolution of a burn patient with polymicrobial healthcare-associated burn infections, including a bloodstream infection due to an emergent multidrug-resistant New Delhi metallo-beta-lactamase (NDM-1)-producing Klebsiella pneumoniae. During hospitalization, initial antibiotic treatment eradicated some of the infecting species. Newer isolates were found to be multidrug-resistant and required unique antibiotic combinations. The patient’s condition continued to deteriorate after the isolation of multidrug-resistant P. aeruginosa and NDM-1-positive K. pneumoniae from the blood. Conclusions: This case report illustrates the need for adequate antibiotic therapies in burn patients with subsequent infections due to a carbapenemase-producing multidrug-resistant bacteria. The potential danger of new bacterial pathogens should be considered in this group of susceptible patients.

Background Linezolid is used to treat vancomycin-resistant enterococcal infections. Vancomycin-resistant and -susceptible Enterococcus faecalis can develop resistance to linezolid in clinical settings with high linezolid consumption. Linezolid-resistant E. faecalis (LREF) has emerged as a major nosocomial pathogen in our hospital, in which linezolid use is considerable.Aim To define risk factors and outcomes associated with LREF infections.Methods A retrospective case-control study was designed to evaluate patients admitted to Hospital Civil de Guadalajara “Fray Antonio Alcalde” from January 2014 to October 2017. Fifty patients meeting case definitions for LREF infection and 100 controls hospitalized in the same rooms and dates as the cases were included. Clinical and demographic data were collected and analyzed.Results Risk factors for LREF, included hospitalization within the previous 6 months, intensive care unit admission, previous surgery, urinary catheterization, parenteral nutrition, and acute renal disease. Multivariate analysis identified prior exposures to linezolid [odds ratio (OR, 6.7] and clindamycin (OR, 6.7), previous hospitalization (OR, 2.8), previous surgery (OR, 5.7), and parenteral nutrition (OR, 3.4) as risk factors for LREF infection. The mortality rate for cases was 18% on the LREF versus 9% for controls.Conclusion Risk factors for LREF infections include antibiotic exposures to linezolid, clindamycin, third-generation cephalosporins, meropenem, and colistin; previous hospitalization; intensive care unit admission; previous surgery; and the use of parenteral nutrition.

The worldwide dissemination of high-risk carbapenemase-producing Klebsiella pneumoniae clones has become a major threat to healthcare facilities. This study describes the successful containment of a hospital outbreak caused by NDM-1-producing K. pneumoniae Sequence Type (ST) 307 using active surveillance. The outbreak began when a patient was transferred from a local hospital. After 48 hours in our hospital, a tracheal aspirate was positive for a meropenem resistant and carbapenemase-producing K. pneumoniae. All patients in the medical intensive care unit (ICU) and the neurology wards were subject to contact precautions. The hospital surfaces and devices, healthcare workers, and patients from these wards were screened by cultures. Fecal swabs were placed into broth and PCR for blaKPC, blaOXA-48, blaIMP, blaVIM, and blaNDM, which were performed directly from the broth after 12 hours. PCRs were also performed on DNA extracted from carbapenemase-producing species from subcultured broths. Five and nine days later, two more patients' rectal swabs tested positive. Molecular assays identified K. pneumoniae blaNDM-1 onto a 130-kb conjugative plasmid (IncY, IncFIIs, and IncFIIY), ST307. After the three patients were discharged, monitoring continued, and after three weeks with negative results, rectal swabbing ended. In conclusion, it was possible to contain a hospital outbreak caused by NDM-1-producing K. pneumoniae ST307 through epidemiological and microbiological surveillance. With the methodology used, the detection of NDM-type genes in fecal samples was obtained in approximately 15 hours after obtaining the fecal sample.

Aim. In this study, we conducted a comparative study to explore the differences in therapeutic efficacy and intestinal microbiome of fecal microbiota transplant (FMT) vs. FMT in addition with Lactobacillus (FMT-L) for treatment of recurrent Clostridioides difficile infection (R-CDI). Methods. We designed a double-blinded randomized comparative two-arm pilot multicenter study to assess the efficacy and impact in the intestinal microbiome of standard capsules of FMT vs. FMT-L enriched with 3 species of Lactobacillus for patients with R-CDI. A 90-day follow-up of 21 patients was performed, starting at the beginning of the study. From the selected patients, fecal samples were obtained at days 0, 3, 7, and 28 after treatment. Fecal samples and FMT were analyzed by 16S rRNA sequencing. Results. We included 21 patients (13 in the FMT group and 8 in the FMT-L group). Overall, both groups had a reduction in bowel movements per day, from 8.6 to 3.2 in the first 48 h (62.7% reduction, p=0.001). No severe adverse reactions or recurrences were recorded. Firmicutes were the most abundant phylum in donors. A low relative abundance of Proteobacteria was detected and mostly found in patients even at higher proportions than the donor. The donor’s pool also had relatively few Bacteroidetes, and some patients showed a higher abundance of this phylum. Based on the ANOSIM R values, there is a significant difference between the microbial communities of basal samples and samples collected on day 7 (p=0.045) and at day 28 (0.041). Conclusion. Fecal microbiota transplant by capsules was clinically and genomically similar between traditional FMT and enriched FMT with Lactobacillus spp. Restoration of bacterial diversity and resolution of dysbiosis at days 7 and 28 were observed. Patients with a first episode of recurrence treated with FMT had an excellent response without severe adverse events; FMT should be considered as an early treatment during R-CDI.

Introduction: The incidence of catheter-related bloodstream infections (CRBSI) ranges from 2.2 to 5.5 episodes per 1,000 catheter-days. Our aim was to evaluate the utility of a generalized and prolonged gentamicin-lock therapy in patients undergoing hemodialysis (HD) in a third-level hospital for the reduction in CRBSI. Methods: A prospective cohort analyzed before and after intervention. During intervention periods after each HD-session, the catheter lumens were locked with gentamicin/heparin for all patients compared to nonintervention periods were the same procedure was performed without gentamicin. Active surveillance was performed for HD CRBSI. Microbiologic assessment and epidemiological data were gathered. Continuous hand hygiene and water quality monitoring were performed. Results: The rates of CRBSI were reduced from 1.28 to 0.2 cases per 1,000 catheter-days when the lock therapy was employed (p = 0.001) The greatest reduction was for CRBSI caused by Pseudomonas aeruginosa were no cases were recorded during the intervention periods (p = 0.001). There was a significant reduction in the total number of isolates; Gram-negative bacterial species (–97.2%) and Gram-positive bacterial species (–61.5%) although only the former reached statistical significance (p = 0.0001). The difference in the absolute risk reduction was 20.56% (95% CI 14.46–26.66%), the calculated Number Needed to Treat was 5 (95% CI 3.8–6.9). No adverse effects were noted. Conclusion: In the current study, gentamicin-lock therapy was associated with a significant reduction in CRBSI specially with P. aeruginosa and other Gram-negative bacteria. It proved to be safe and effective intervention when applied to the entire population of HD patients.

Helicobacter pylori is a Gram-negative bacterium that causes chronic gastritis, dyspepsia, peptic ulcers, and gastric cancer. Over half the world's population is infected with H. pylori, with higher prevalence in developing countries. Areas covered: In this review, current guidelines on H. pylori therapy, such as the Toronto consensus statement, the Maastricht V/Florence consensus report, and the American College of Gastroenterology guidelines, are compared. Also, we analyzed reports of antimicrobial resistance of H. pylori published in PubMed in the last years to determine current antimicrobial resistance worldwide. Expert commentary: Although H. pylori antimicrobial resistance varies by geographic area, its prevalence has been increasing over time, causing therapy failures and low eradication rates. To best optimize the management of H. pylori infection, H. pylori therapy should be based on patterns of local and individual antimicrobial resistance, if possible.

Aim We aimed to assess the resistance rates of antimicrobial-resistant, in bacterial pathogens of epidemiological importance in 47 Mexican centers. Material and methods In this retrospective study, we included a stratified sample of 47 centers, covering 20 Mexican states. Selected isolates considered as potential causatives of disease collected over a 6-month period were included. Laboratories employed their usual methods to perform microbiological studies. The results were deposited into a database and analyzed with the WHONET 5.6 software. Results In this 6-month study, a total of 22,943 strains were included. Regarding Gram-negatives, carbapenem resistance was detected in ≤ 3% in Escherichia coli, 12.5% in Klebsiella sp. and Enterobacter sp., and up to 40% in Pseudomonas aeruginosa; in the latter, the resistance rate for piperacillin-tazobactam (TZP) was as high as 19.1%. In Acinetobacter sp., resistance rates for cefepime, ciprofloxacin, meropenem, and TZP were higher than 50%. Regarding Gram-positives, methicillin resistance in Staphylococcus aureus (MRSA) was as high as 21.4%, and vancomycin (VAN) resistance reached up to 21% in Enterococcus faecium. Acinetobacter sp. presented the highest multidrug resistance (53%) followed by Klebsiella sp. (22.6%) and E. coli (19.4%). Conclusion The multidrug resistance of Acinetobacter sp., Klebsiella sp. and E. coli and the carbapenem resistance in specific groups of enterobacteria deserve special attention in Mexico. Vancomycin-resistant enterococci (VRE) and MRSA are common in our hospitals. Our results present valuable information for the implementation of measures to control drug resistance.

Acinetobacter baumannii has emerged as a dangerous nosocomial pathogen, particularly for severely ill patients in intensive care units and patients with hematologic malignancies. Here, we present the complete genome sequence of a multidrug-resistant A. baumannii isolate, recovered from a Mexican hospital and classified as sequence type 422 according to the multilocus sequence typing Pasteur scheme.

Nocardia brasiliensis is an intracellular microorganism and the most common etiologic agent of actinomycetoma in the Americas. Several intracellular pathogens induce an immunosuppressive microenvironment through increases in CD4 + Foxp3 + regulatory T cells (Treg), thus downregulating other T-cell subpopulations and assuring survival in the host. In this study, we determined whether N. brasiliensis modulates T-lymphocyte responses and their related cytokine profiles in a murine experimental model. We also examined the relationship between N. brasiliensis immunomodulation and pathogenesis and bacterial survival. In early infection, Th17/Tc17 cells were increased at day 3 ( P < 0.05) in footpad tissue and spleen. Treg subpopulations peaked at days 7 and 15 ( P < 0.01) in the footpad and spleen, respectively. Transforming growth factor β1 (TGF-β1) and interleuki-10 (IL-10) are cytokines known for their immunosuppressive effects. During early and chronic infections, these cytokines were elevated with increased TGF-β1 levels from days 3 to 30 ( P < 0.01) and sustained IL-10 expression throughout infection compared to uninfected mice. IL-6 production was increased at day 3 ( P < 0.01), whereas gamma interferon (IFN-γ), IL-17A, and IL-23 levels were highest at day 15 postinfection ( P < 0.01) when a decrease in the bacterial load (>1 log) was also observed ( P < 0.05). After these changes, at 30 to 60 days postinfection, IFN-γ production was decreased, whereas the expression of anti-inflammatory cytokines and the bacterial load again increased ( P < 0.05). The increment in Treg cells and the related cytokine profile correlated with reduced inflammation at day 15 ( P < 0.05) in the footpad. We conclude that N. brasiliensis modulates the immune system to induce an immunosuppressive microenvironment that benefits its survival during the chronic stage of infection.

Introduction Enterococcus faecium has emerged as a multidrug-resistant nosocomial pathogen involved in outbreaks worldwide. Our aim was to determine the antimicrobial susceptibility, biofilm production, and clonal relatedness of vancomycin-resistant E. faecium (VREF) clinical isolates from two hospitals in Mexico. Methods Consecutive clinical isolates ( n = 56) were collected in two tertiary care hospitals in Mexico from 2011 to 2014. VREF isolates were characterized by phenotypic and molecular methods including pulsed-field gel electrophoresis (PFGE). Results VREF isolates were highly resistant to vancomycin, erythromycin, norfloxacin, high-level streptomycin, and teicoplanin, and showed lower resistance to tetracycline, nitrofurantoin and quinupristin-dalfopristin. None of the isolates were resistant to linezolid. The vanA gene was detected in all isolates. Two VanB phenotype- vanA genotype isolates, highly resistant to vancomycin and susceptible to teicoplanin, were detected. Furthermore, 17.9% of the isolates were classified as biofilm producers, and the espfm gene was found in 98.2% of the isolates. A total of 37 distinct PFGE patterns and 6 clones (25% of the isolates as clone A, 5.4% as clone B, and 3.6% each as clone C, D, E, and F) were detected. Clone A was detected in 5 different wards of the same hospital during 14 months of surveillance. Conclusion The high resistance to most antimicrobial agents and the moderate cross-transmission of VREF detected accentuates the need for continuous surveillance of E. faecium in the hospital setting. This is also the first reported incidence of the E. faecium VanB phenotype- vanA genotype in the Americas.