Thoracic ultrasound alone or in combination with tracheal amylase as a tool predictor of ventilator-associated pneumonia in neurocritical patients.

In this study, we aim to evaluate whether thoracic ultrasound (TUS) and tracheal amylase (TA) alone or in combination can predict the development of ventilator-associated pneumonia (VAP) in neurocritical patients. Consecutive adult patients with neurocritical disease with normal chest radiographs who required intensive care unit admission and mechanical ventilation between March 2015 and July 2018 were included. TUS and Amylase levels were measured during the first 24 hours and repeated 48 hours after orotracheal intubation. Forty-three patients with a median age of 34 years (17-82) were included. TUS had a sensitivity of 100% and specificity of 96.3% as a predictor of VAP within the first 48 hours when nonpattern A was observed. TA levels > 200 UI/L in the first 48 hours had a sensitivity of 87.5%, and specificity of 63% as a predictor of VAP. Moreover, no benefit of TUS plus TA compared to TUS alone as a predictor of VAP was found. The identification of abnormal TUS patterns in the first 48 hours of orotracheal intubation is a significant predictor of VAP in neurocritical patients.

First case of Candida auris isolated from the bloodstream of a Mexican patient with serious gastrointestinal complications from severe endometriosis.

A 58-year-old woman was diagnosed with severe endometriosis and had multiple gastrointestinal tract complications for many years. Candida auris and C. parapsilosis were isolated from the bloodstream. Identification of C. auris was confirmed by amplification and sequencing of the internal transcriber spacer and the D1/D2 domain of the large rRNA gene subunit. Antifungal susceptibility was tested in both isolates using the Clinical Laboratory Standards Institute protocol M27-A3/S4. The patient evolved favorably with systemic antifungal therapy consisting of caspofungin and liposomal amphotericin B.

Assessment of software-derived predictive algorithms for platelet yield and blood cell count after apheresis.

INTRODUCTION: Algorithms have been developed to predict the platelet yield after apheresis from the donor's data, as well as the effect on the blood cell count, to extract an acceptable platelet number without affecting the donor. However, the evaluation of these algorithms has not been widely reported. This study aimed to assess the accuracy of the predictive algorithms of the Trima Accel v. 6 blood collection system. METHODS: Platelet concentrates (PCs) obtained by apheresis were analyzed. Platelet count and hematocrit were compared pre- and post-apheresis. Calculated post-apheresis platelet count (CPAPC), hematocrit (CPAH), and platelet yield (CPY), and their actual values were correlated. The bias of the algorithms was assessed with Bland-Altman plots, and the prediction of the extraction of single or double platelet products was evaluated. RESULTS: Two hundred and seventy-nine PCs were analyzed. Post-apheresis platelet count (PAPC) and hematocrit were decreased. A moderate correlation was observed between CPY and the actual yield, with a negative bias, and a trend to increase alongside the magnitude of the measurements. CPAPC and CPAH were strongly correlated with their actual values without bias. Prediction of single or double platelet product extraction showed a significant agreement with the actual outcomes. CONCLUSIONS: The predictive algorithm for the platelet yield showed bias, and a trend to underestimate the actual platelet yields when they are higher. The algorithms for the prediction of the PAPC and hematocrit did not show bias, proving their accuracy. Prediction of a single or double platelet product extraction has a strong agreement with the APY.

Surveillance of antimicrobial resistance in Serratia marcescens in Mexico.

Antimicrobial resistance is a global public health threat. Therefore, surveillance studies are important tools to help direct antimicrobial use. The aim of this study was to investigate antimicrobial resistance in Serratia marcescens isolates collected in 2016-2017 at eight medical centers from two regions of Mexico. Selected S. marcescens isolates were further tested by polymerase chain reaction to detect the presence of genes encoding the ß-lactamases, SHV, TEM or CTX. Antimicrobial resistance continues to be high in Mexico, particularly to ciprofloxacin and aminoglycosides. Also, a widespread prevalence of blaTEM was detected in S. marcescens isolates.

Non-typeable Haemophilus influenzae biofilm production and severity in lower respiratory tract infections in a tertiary hospital in Mexico.

Non-typeable Haemophilus influenzae (NTHi) is a common opportunistic bacterial pathogen that primarily infects the respiratory mucosa. This study was conducted to assess clinical and microbiological data related to disease severity in patients with lower respiratory tract infections caused by NTHi in a tertiary care hospital in Mexico. NTHi isolates were subjected to serotyping, antimicrobial susceptibility evaluationand analyses of ß-lactamase production, genetic relatednessand biofilm formation. Clinical and demographic data were retrieved from patients' records. The mean age of the patients was 40.3 years; the majority (n=44, 72.1 %) were male. The main comorbidities were arterial hypertension (n=22, 36.1 %) and diabetes mellitus (n=17, 27.9 %). NTHi isolates (n=98) were recovered from tracheal aspirate (n=57, 58.2 %), sputum (n=26, 26.5 %)and bronchial aspirate (n=15, 15.3 %) specimens. Low resistance to cefotaxime (n=0, 0.0 %), rifampin (n=1, 1.1 %) and chloramphenicol (n=3, 3.2 %) and greater resistance to ampicillin (n=30, 32.3 %) and trimethoprim-sulfamethoxazole (n=49, 52.7 %) were detected. ß-Lactamase production was found in 17 (17.3 %) isolates. Isolates displayed high genetic diversity, and only 10 (10.2 %) were found to be biofilm producers. The antimicrobial susceptibility patterns of biofilm-producing and non-producing isolates did not differ. Biofilm production was associated with prolonged hospital stay (P=0.05). Lower respiratory NTHi isolates from Mexico showed low antimicrobial resistance and weak biofilm production. Younger age was correlated with lower Acute Physiology and Chronic Health Evaluation II score (moderate, P=0.07; severe, P=0.03).

First report of Clostridium difficile NAP1/027 in a Mexican hospital.

BACKGROUND AND OBJECTIVE: Clostridium difficile NAP1/ribotype 027 is associated with severe disease and high mortality rates. Our aim was to determine the prevalence of NAP1/ribotype 027 among C. difficile isolates in a tertiary care hospital, and review the main clinical data. METHODS: We included 106 stool samples from 106 patients. Samples were tested for A&B toxins and were cultured on CCFA agar. The genes tcdA, tcdB, tcdC, cdtA, and cdtB were amplified using PCR in clinical isolates. The tcdA 3'-end deletion analysis, PCR-ribotyping, and pulsed-field gel electrophoresis (PFGE) were also performed. Stool samples that were positive for culture were tested by the GeneXpert C. difficile assay. Clinical data were collected. RESULTS: Thirty-six patients tested positive for A&B toxins; and 22 patients had positive culture for C. difficile, 14 of which tested positive for the A&B toxins and all 22 patients tested positive by the GeneXpert C. difficile assay. Risk factors included an average hospital stay of 16.1 days prior to toxin detection, average antibiotic use for 16.2 days, and a median of 3 antibiotics used. The 30-day crude mortality rate was 8.4%. Six of the 22 patients died, and 3 of those deaths were directly attributed to C. difficile infection. The majority of isolates, 90.9% (20/22), carried genes tcdB, tcdA, cdtA, and cdtB; and these strains carried the corresponding downregulator gene tcdC, with an 18-bp deletion. PFGE was performed on 17 isolates, and one main pattern was observed. Analysis of the ribotyping data showed similar results. CONCLUSION: The above findings represent the clonal spread of C. difficile in our institution, which mainly includes the NAP1/027 strain. This is the first report of C. difficile ribotype NAP1/027 in Mexico.

Stenotrophomonas maltophilia in Mexico: antimicrobial resistance, biofilm formation and clonal diversity.

Stenotrophomonas maltophilia is an important multidrug-resistant nosocomial pathogen associated with high mortality. Our aim was to examine antimicrobial susceptibility, biofilm production and clonal relatedness of clinical isolates of S. maltophilia. S. maltophilia isolates were collected between 2006 and 2013 from two tertiary care hospitals in Mexico. Antimicrobial susceptibility was evaluated by the broth microdilution method. PCR was used to determine the presence of ß-lactamase genes L1 and L2. Biofilm formation was assessed with crystal violet staining. Clonal relatedness was determined by PFGE. Among the 119 collected S. maltophilia isolates, 73 (61.3%) were from the respiratory tract. Resistance levels exceeded 75% for imipenem, meropenem, ampicillin, aztreonam, gentamicin and tobramycin. Resistance to trimethoprim-sulfamethoxazole was 32.8%. L1 and L2 genes were detected in 77.1% (91/118) and 66.9% (79/118) of isolates, respectively. All S. maltophilia strains were able to produce biofilms. Strains were classified as weak (47.9%, 57/119), moderate (38.7%, 46/119), or strong (13.4%, 16/119) biofilm producers. A total of 89 distinct PFGE types were identified and 21.6% (22/102) of the isolates were distributed in nine clusters. This is the first study in Mexico to reveal characteristics of clinical isolates of S. maltophilia. Clonal diversity data indicate low cross-transmission of S. maltophilia in a hospital setting. The high antibiotic resistance underscores the need for continuous surveillance of S. maltophilia in hospital settings in Mexico.

[Comparative study of a rapid testing with real time RT-PCR for diagnosis of influenza AH1N1 2009]. / Estudio comparativo entre una prueba rápida y RT-PCR tiempo real en el diagnóstico de influenza AH1N1 2009.

OBJECTIVE: Compare QuickVue Influenza A+B test with real-time RT-PCR for the diagnosis of influenza AH1N1 2009. MATERIAL AND METHODS: Retrospective-comparative study of 135 respiratory specimens from individuals with symptoms of influenza processed from May 2009 to October 2010.The above mentioned tests were performed simultaneously. For statistic analysisthe softwareof Confidence IntervalAnalysis 2000 was used. RESULTS: The parameters obtained were: sensitivity 62.96; specificity 94.44; negative predictive value 62.9; positive predictive value 94.44; positive likelihood ratio 11.33; negative likelihood ratio 0.39. Confidence intervals to 95,were calculated to all of the above data. DISCUSSION: The test QuickVue InfluenzaA+B is a rapid,simple test,with lower cost than real-time RT-PCR useful for identifying the type of virus outbreaks of influenza in a given population.It correlates well with more specific test and similar reports.

Estudio comparativo entre una prueba rápida y RT-PCR tiempo real en el diagnóstico de influenza AH1N1 2009 / Comparative study of a rapid testing with real time RT-PCR for diagnosis of influenza AH1N1 2009

OBJETIVO: Comparar la prueba QuickVue Influenza A+B empleando como estándar la RT-PCR tiempo real para influenza AH1N1 2009. MATERIAL Y MÉTODOS: Estudio retrospectivo-comparativo de 135 muestras de vías respiratorias de individuos sintomáticos para influenza procesadas de mayo 2009 a octubre 2010.Las pruebas citadas se realizaron simultáneamente. Se utilizó el software Confidence Interval Analysis 2000. RESULTADOS: Sensibilidad 62.96; especificidad 94.44; valor predictivo negativo 62.9; valor predictivo positivo 94.44; razón de probabilidad positiva 11.33 y razón de probabilidad negativa 0.39. Se calcularon intervalos de confianza a 95. DISCUSIÓN: Los valores obtenidos concuerdan con otros estudios donde la sensibilidad fluctúa de 50 a 70 y especificidad entre 90 y 95 por ciento. La prueba QuickVue Influenza A+B es rápida, simple y de menor costo que el RT-PCR tiempo real, útil para identificar el tipo de virus en brotes de influenza de una población determinada.

OBJECTIVE: Compare QuickVue Influenza A+B test with real-time RT-PCR for the diagnosis of influenza AH1N1 2009. MATERIAL AND METHODS: Retrospective-comparative study of 135 respiratory specimens from individuals with symptoms of influenza processed from May 2009 to October 2010.The above mentioned tests were performed simultaneously. For statistic analysisthe softwareof Confidence IntervalAnalysis 2000 was used. RESULTS: The parameters obtained were: sensitivity 62.96; specificity 94.44; negative predictive value 62.9; positive predictive value 94.44; positive likelihood ratio 11.33; negative likelihood ratio 0.39. Confidence intervals to 95,were calculated to all of the above data. DISCUSSION: The test QuickVue InfluenzaA+B is a rapid,simple test,with lower cost than real-time RT-PCR useful for identifying the type of virus outbreaks of influenza in a given population.It correlates well with more specific test and similar reports.

Molecular characterization and antimicrobial susceptibility of extended-spectrum {beta}-lactamase-producing Enterobacteriaceae isolates at a tertiary-care centre in Monterrey, Mexico.

Our objective was to analyse phenotypic and genetic data of extended-spectrum ß-lactamase (ESBL)-producing Klebsiella pneumoniae, Enterobacter cloacae, Escherichia coli and Serratia marcescens that cause infections in our hospital. Over a 3 year period, 342 randomly selected clinical Enterobacteriaceae isolates were tested for ESBL production and evaluated for the presence of the ß-lactamase genes bla(SHV), bla(TEM,) bla(CTX-M) and bla(TLA-1). The antibiotic susceptibilities of these isolates were also determined, and the clonality of the isolates was assessed by PFGE. Based on our analyses, 33/92 (35.9 %) K. pneumoniae, 31/87 (35.6 %) Enterobacter cloacae, 24/80 (30 %) E. coli and 17/83 (20.5 %) S. marcescens were identified as ESBL producers. The presence of TEM, SHV or CTX ESBL types was detected in 99/105 (94 %) of the isolates. TLA-1 was not detected in any of the 105 isolates. The dominant ESBL types were bla(SHV-5) (n=33), bla(SHV12) (n=31) and bla(CTX-M-15) (n=30). The predominant ESBL identified in E. coli and Enterobacter cloacae isolates was CTX-M-15, whereas in K. pneumoniae and S. marcescens the predominant types were SHV-12 and SHV-5, respectively. PFGE genotyping revealed two main genetic patterns in the K. pneumoniae isolates, types SHV-12 and TEM-1+SHV-5. An outbreak caused by Enterobacter cloacae SHV-5+CTX-M-15 was detected. In contrast, most ESBL-producing isolates of E. coli and S. marcescens did not have similar PFGE banding patterns and thus were not genetically similar. Enterobacteriaceae are a concern in our hospital, especially K. pneumoniae and Enterobacter cloacae. Our results confirm that the CTX-M-15 ESBL type has spread rapidly in the hospital, and thus requires careful monitoring.

Evaluation of Sensititre plates for identification of clinically relevant coagulase-negative staphylococci.

Coagulase-negative staphylococcus isolates were identified using Sensititre GPID plates and API strips (n = 156). For selected isolates, partial sequencing of the 16S rRNA, sodA, and tuf genes was performed. The Sensititre plates correctly identified 68.9% of isolates, with a concordance of 86% for Staphylococcus haemolyticus and 73% for Staphylococcus epidermidis.

Diversity of staphylococcal cassette chromosome mec structures in coagulase-negative staphylococci and relationship to drug resistance.

The objective of this study was to determine the distribution of staphylococcal cassette chromosome mec (SCCmec) elements in meticillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from a tertiary-care hospital in Mexico and to examine the relationship to drug resistance. Fifty selected MR-CoNS isolates collected from catheters (n=15), blood (n=15), bone (n=9), bronchial lavage (n=2) and urine (n=2) and one isolate each from an abscess, cerebrospinal fluid, eye, pleural effusion, synovial fluid, tracheal aspirate and wound secretion were examined. Susceptibility testing was performed by the broth microdilution method. SCCmec types were determined by multiplex PCR and PFGE was carried out as described previously for Staphylococcus aureus. Among the MR-CoNS strains studied, the most frequently isolated species were Staphylococcus epidermidis (n=26) and Staphylococcus haemolyticus (n=13). Staphylococcus cohnii (n=5), Staphylococcus hominis (n=3), Staphylococcus sciuri (n=1), Staphylococcus pasteuri (n=1) and the recently described species Staphylococcus pettenkoferi (n=1) were also identified. The most frequent MR-CoNS genotype identified was SCCmec type IVa in S. epidermidis isolates, which also showed a high diversity in their PFGE patterns. A clone was found that amplified both SCCmec III and V elements in five isolates examined. The single MR S. pettenkoferi isolate harboured SCCmec type IVd and the single MR S. pasteuri isolate harboured SCCmec type I. The carriage of SCCmec type III was associated with resistance or intermediate resistance to meropenem (P <0.05). These results confirm the high prevalence of S. epidermidis SCCmec IVa and the high genetic diversity among MR-CoNS strains. As far as is known, this is the first report describing the newly identified S. pettenkoferi possessing SCCmec IVd and S. pasteuri harbouring SCCmec type I. MR-CoNS harbouring SCCmec type III were found to be more resistant to meropenem.