Thymidine-dependent Staphylococcus aureus and lung function in patients with cystic fibrosis: a 10-year retrospective case-control study.

OBJECTIVE: Thymidine-dependent small-colony variants (TD-SCVs) of Staphylococcus aureus are being isolated with increasing frequency from patients with cystic fibrosis (CF). The aim of this study was to evaluate the relationship between TD-SCV isolation and pulmonary function in patients with CF, as well as to determine whether the emergence of TD-SCVs was associated with trimethoprim-sulfamethoxazole (TMP-SMX) use and with coinfection with other microorganisms. METHODS: This was a retrospective case-control study including patients with CF who visited the Clinical Hospital Complex of the Federal University of Paraná, in Curitiba, Brazil, between 2013 and 2022. Demographic, clinical, and spirometric data, as well as information on TD-SCVs and other isolated microorganisms, were collected from the medical records of patients with CF and TD-SCVs (TD-SCV group; n = 32) and compared with those of a matched group of patients with CF without TD-SCVs (control group; n = 64). RESULTS: Isolation of TD-SCVs was positively associated with TMP-SMX use (p = 0.009), hospitalization (p < 0.001), and impaired pulmonary function (p = 0.04). CONCLUSIONS: The use of TMP-SMX seems to contribute to the emergence of TD-SCVs, the isolation of which was directly associated with worse pulmonary function in our sample.

Drug Resistance in Biofilm and Planktonic Cells of Achromobacter spp., Burkholderia spp., and Stenotrophomonas maltophilia Clinical Isolates.

Background: Biofilm production in nonfermenting Gram-negative bacteria influences drug resistance. The aim of this work was to evaluate the effect of different antibiotics on biofilm eradication of clinical isolates of Achromobacter, Burkholderia, and Stenotrophomonas maltophilia. Methods: Clinical isolates were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry in a third-level hospital in Monterrey, Mexico. Crystal violet staining was used to determine biofilm production. Drug susceptibility testing was determined by broth microdilution in planktonic cells and biofilm cells. Results: Resistance in planktonic cells was moderate to trimethoprim-sulfamethoxazole, and low to chloramphenicol, minocycline, levofloxacin (S. maltophilia and Burkholderia), ceftazidime, and meropenem (Burkholderia and Achromobacter). Biofilm eradication required higher drug concentrations of ceftazidime, chloramphenicol, levofloxacin, and trimethoprim-sulfamethoxazole than planktonic cells (p < 0.05). Levofloxacin showed biofilm eradication activity in S. maltophilia, minocycline and meropenem in Burkholderia, and meropenem in Achromobacter. Conclusions: Drug resistance increased due to biofilm production for some antibiotics, particularly ceftazidime and trimethoprim-sulfamethoxazole for all three pathogens, chloramphenicol for S. maltophilia and Burkholderia, and levofloxacin for Burkholderia. Some antibiotics could be used for the treatment of biofilm-associated infections in our population, such as levofloxacin for S. maltophilia, minocycline and meropenem for Burkholderia, and meropenem for Achromobacter.

Trends in the Prevalence of Antimicrobial Resistance in Escherichia coli Isolated from Outpatient Urine Cultures in French Amazonia.

Antimicrobial resistance (AMR) in the community is increasing worldwide. We aimed to assess AMR trends in Escherichia coli from the community urine isolates in French Amazonia. We conducted a retrospective study from January 2016 to December 2022 in the Cayenne General Hospital microbiology laboratory (French Guiana). It included all urine samples positive for E. coli collected from adult outpatients. During the study period, 3,443 urinalyses positive for E. coli were studied. In 46% of cases, patients were women. In 64.4% of cases, E. coli were ß-lactamase producers. The most frequently diagnosed resistance mechanisms were penicillinase production and sparing third-generation cephalosporins. Isolated E. coli were extended-spectrum ß-lactamase (ESBL) producers in 6.1% of cases. Overall, E. coli was susceptible to amoxicillin in 35.9% [95% CI: 34.3-37.5], to amoxicillin/clavulanic acid in 62.2% [95% CI: 60.6-63.9], to cefotaxime in 94% [95% CI: 93.1-94.7], to gentamicin in 92.1% [95% CI: 89.1-92.6], to ofloxacin in 76.8% [95% CI: 75.3-78.2], to trimethoprim/sulfamethoxazole (SXT) in 58.8% [95% CI: 57.1-60.5], to fosfomycin in 99.1% [95% CI: 98.6-99.4], and to nitrofurantoin in 99% of cases [95% CI: 98.6-99.3]. We have observed a gradual decline in the susceptibility profile of E. coli for amoxicillin/clavulanic acid (P <0.001), piperacillin/tazobactam (P = 0.003), and temocillin (P = 0.006). However, susceptibility to ciprofloxacin was increasing (P = 0.001). In contrast, the susceptibility trends for amoxicillin, third-generation cephalosporins, gentamicin, SXT, nitrofurantoin, and fosfomycin remained stable over the 28 quarters of the study. In conclusion, isolated E. coli from outpatient urinalyses showed increased resistance profiles involving penicillinase and ESBL production. Close monitoring and strategies to decrease antibiotic consumption in the community are needed.

Biofilm Eradication of Stenotrophomonas maltophilia by Levofloxacin and Trimethoprim-Sulfamethoxazole.

Stenotrophomonas maltophilia is a nonfermenting Gram-negative drug-resistant pathogen that causes healthcare-associated infections. Clinical isolates from Mexico were assessed for biofilm formation using crystal violet staining. Antimicrobial susceptibility was evaluated in planktonic and biofilm cells using the broth microdilution method. The effects of antibiotics on biofilms were visualized using fluorescence microscopy. Fifty isolates were included in this study, of which 14 (28%) were biofilm producers (9 [64%] from blood and 5 [36%] from respiratory samples). In planktonic cells 4/50 (8%) of isolates were resistant to levofloxacin (8.0%) and 22/50 (44%) were resistant to trimethoprim-sulfamethoxazole. All isolates were resistant to levofloxacin and trimethoprim-sulfamethoxazole in biofilm cells. Bacterial biofilms treated with different concentrations of both antibiotics were completely disrupted. In conclusion, S. maltophilia isolated from blood had higher biofilm production than those isolated from respiratory samples. Biofilm production was associated with increased antibiotic resistance. Antibiotic monotherapy might not be the best course of action for the treatment of S. maltophilia infections in Mexico, because it might cause biofilm production and antimicrobial resistance.

Antibiofilm and antimicrobial activity of curcumin-chitosan nanocomplexes and trimethoprim-sulfamethoxazole on Achromobacter, Burkholderia, and Stenotrophomonas isolates.

BACKGROUND: Non-fermenting Gram-negative Achromobacter xylosoxidans, Burkholderia cepacia complex, and Stenotrophomonas maltophilia species cause healthcare-associated infections, often showing resistance to first-line drugs such as trimethoprim-sulfamethoxazole (TMP-SXT). The aim of this study was to determine the effect of curcumin-chitosan nanocomplexes on biofilm-producing clinical isolates of non-fermenting Gram-negative bacilli. METHODS: A. xylosoxidans, B. cepacia complex, and S. maltophilia clinical isolates were identified by MALDI-TOF mass spectrometry. Antimicrobial susceptibility was determined by broth microdilution. Curcumin (Cur), chitosan (Chi), and sodium tripolyphosphate (TPP) were encapsulated by ionotropic gelation in magnetic nanoparticles (MNP) and were assessed by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR). Biofilm inhibition and eradication by Cur-Chi-TPP-MNP with TMP-SXT was assessed. RESULTS: Cur-Chi-TPP-MNP in combination with TMP-SXT showed biofilm inhibition activity in A. xylosoxidans (37.5 µg/mL), B. cepacia (18.75 µg/mL), and S. maltophilia (4.69-18.75 µg/mL) and low biofilm eradication activity in all three strains (150 - 300 µg/mL). CONCLUSIONS: Cur-Chi-TPP-MNP in combination with TMP-SXT was able to inhibit biofilm and in lower effect to eradicate established biofilms of clinical isolates of A. xylosoxidans, B. cepacia complex, and S. maltophilia species. Our results highlight the need to assess these potential treatment options to be used clinically in biofilm-associated infections.

Antibody- Based Immunotherapy Combined With Antimycotic Drug TMP- SMX to Treat Infection With Paracoccidioides brasiliensis.

Monoclonal antibodies (mAbs) are promising alternatives to treat infectious diseases, especially given their potential for applications in combination therapies with antimicrobial drugs to enhance the antifungal efficacy. Protection mediated by mAbs used to treat experimental paracoccidioidomycosis (PCM) has been demonstrated previously. Our aim in the present work was to characterize a monoclonal antibody (mAbF1.4) raised against a cell wall glycoconjugate fraction of Paracoccidioides spp. and to analyze its efficacy combined with trimethoprim-sulfamethoxazole (TMP/SMX) as treatment for experimental PCM. We demonstrated that the epitope recognized by mAbF1.4 is consistent with branched glucose residues present on a cell wall ß-glucan polymer. In vitro, mAbF1.4 increased the phagocytic capacity and nitric oxide concentration induced by the macrophage cell line J774.1A, and this resulted in a significant reduction in the viability of the opsonophagocytized yeasts. In vivo, we detected a significant reduction in pulmonary fungal burdens of mice treated with mAbF1.4 in association with TMP/SMX, which correlated with increased pulmonary concentrations (determined by ELISA) of IFN- Î³, TNF-α, IL-10 and IL-17. In parallel, we observed a decrease in IL-4, suggesting that the treatment was associated with a mixed Th1-Th17 type immune response. Histopathology of lung segments from mice receiving the combination therapy showed a significant reduction in granulomas, which were well-defined, and improved maintenance of lung architecture. These findings demonstrate that mAbF1.4 + TMP/SMX therapy is a promising approach to combat PCM as well as decrease disease sequelae and highlights the potential benefits of immune mediators in PCM combined immunotherapy.

Effect of antimicrobials on Stenotrophomonas maltophilia biofilm.

Aim: To evaluate the activity of five antimicrobials against young and mature Stenotrophomonas maltophilia biofilms. Materials & methods: Nineteen clinical strains from hemoculture of hemodialysis patients were tested for biofilm kinetics, MIC and minimum biofilm inhibitory concentration (MBIC) in young and mature biofilms. Results: All strains were moderate biofilm producers. MIC showed total susceptibility to levofloxacin and trimethoprim-sulfamethoxazole and partial resistance to ceftazidime (63.2%) and gentamicin (21%). Young and mature biofilms showed the lowest MBIC/MIC ratio for gentamicin, chloramphenicol and levofloxacin, respectively. The highest MBIC/MIC was for trimethoprim-sulfamethoxazole (young) and ceftazidime (mature). Conclusion: Gentamicin displayed surprising activity against S. maltophilia biofilms. Chloramphenicol was indicated as a good option against young S. maltophilia biofilms, and trimethoprim-sulfamethoxazole showed limited antibiofilm activity.

Clinical and microbiological characteristics of patients colonized or infected by Stenotrophomonas maltophilia : is resistance to sulfamethoxazole/trimethoprim a problem?

Stenotrophomonas maltophilia has emerged as an important opportunistic pathogen in the last decade. Increased resistance to sulfamethoxazole/trimethoprim (SMX/TMP) has been reported in S. maltophilia strains in the past few years, leading to few therapeutic options. We conducted a prospective multicenter study at two Brazilian teaching hospitals that identified S. maltophilia isolates and evaluated their antimicrobial susceptibility profile, SMX/TMP resistance genes and their clonality profile. A total of 106 non-repeated clinical samples of S. maltophilia were evaluated. Resistance to SMX/TMP was identified in 21.6% of the samples, and previous use of SMX/TMP occurred in 19 (82.6%). PCR detected the sul1 gene in 14 of 106 strains (13.2%). Of these isolates, nine displayed resistance to SMX/TMP. The resistant strains presented a polyclonal profile. This opportunistic pathogen has emerged in immunocompromised hosts, with few therapeutic options, which is aggravated by the description of emerging resistance mechanisms, although with a polyclonal distribution profile.

Supersaturating drug delivery system of fixed drug combination: sulfamethoxazole and trimethoprim.

Background: The drug supersaturation in the intestinal lumen for few hours could result in high bioavailability. The goal of this study was the development of a supersaturating drug delivery system containing sulfamethoxazole and trimethoprim at fixed dose combination (sulfamethoxazole:trimethoprim 5:1 w/w). Methods: The amorphous solid dispersions were formed at three different proportions containing 30, 50 and 70% of Eudragit EPO in the formulation. Results: The supersaturation state is formed by the amorphous drugs produced by spray drying technique, and the maintenance of this state is due to the chemical interactions between the drugs and the polymer selected, which was observed in the fluorescence interaction studies realized between the drugs and the polymer. The Formulation containing 70% of the polymer was able to produce and maintain the supersaturated state of both drugs for 24 h. Solid state characterization demonstrated the amorphization of the drugs in the solid dispersion and indicated the hydrogen bond formation responsible for the improvement in the apparent solubility. This formulation presented an improved antibacterial activity when compared to the combination of the drugs. Conclusion: For the first time, a supersaturating drug delivery system was developed to the complementary antibacterial drugs. This ternary formulation is a powerful alternative to improve oral absorption of recognized safety drugs, reducing the dose and consequently the antibiotic resistance emergence.

[Susceptibility of Streptococcus pyogenes isolated from invasive infections to trimethoprim-sulfamethoxazole]. / Sensibilidad a trimetoprima-sulfametoxazol de Streptococcus pyogenes aislados de infecciones invasivas.

It is erroneously believed that group A streptococci (GAS) are universally resistant to trimethoprim-sulfamethoxazole (TMS). This is mainly because media commonly used for in vitro determination of susceptibility to antibiotics contain thymidine, a nucleoside that antagonizes the antibiotic effect of TMS. The objective of this work was to determine EGA sensitivity to TMS in the presence and absence of thymidine. To this aim, 95 GAS isolates obtained from clinical tissues with i nvasive infections were analyzed. Susceptibility tests were performed by diffusion with TMS discs in Mueller Hinton agar supplemented either with 5% sheep blood or with 5% lysed equine blood (MH-LEB). Lysed equine blood contains thymidine phosphorylase, which degrades this nucleoside. Epsilometry (Etest) was used as gold standard. Quality controls with Enterococcus faecalis strain ATCC 29212 were satisfactory with both media. A 100% sensitivity to TMS was found in MH-SEL whereas 6 isolates (6.3%) resulted resistant in MH-SC; only one of them was found to have intermediate susceptibility by Etest (MIC > 1.5/28 υg/ml). The genetic determinants most frequently associated to TMS resistant EGA were not found in this isolate. Probably, if more accurate GAS-specific cut-off points were established for diffusion, the correlation with dilution methods or with the Etest could be improved, even employing MH-SB.

Computer-aided identification of novel anti-paracoccidioidomycosis compounds.

AIM: The shape-based virtual screening was used for the identification of new compounds anti-paracoccidioidomycosis (PCM). MATERIALS & METHODS: The study was performed according to the following steps: collection and curation of a dataset of quinolinyl N-oxide chalcones with anti-PCM activity, development and validation of shape-based models, application of the best model for virtual screening, and experimental validation. RESULTS & CONCLUSION: Among 31 computational hits, eight compounds showed potent antifungal activity and low cytotoxicity for mammalian cells. The checkerboard assay showed that most promising hit (compound 3) displayed additive effects with the antifungal cotrimoxazole and amphotericin B. Therefore, the shape-based virtual screening allowed us to discover promising compounds in prospective hit-to-lead optimization studies for tackling PCM.

Sensibilidad a trimetoprima-sulfametoxazol de Streptococcus pyogenes aislados de infecciones invasivas / Susceptibility of Streptococcus pyogenes isolated from invasive infections to trimethoprim-sulfamethoxazole

Se cree erróneamente que los estreptococos del grupo A (EGA) son universalmente resistentes a trimetoprima-sulfametoxazol (TMS). Esto se debe a que la timidina presente en los medios habitualmente usados para determinar sensibilidad in vitro a antibióticos antagoniza el efecto antibiótico de TMS. El objetivo de este trabajo fue determinar la sensibilidad de EGA a TMS, en presencia y ausencia de timidina. A tal fin, fueron analizados 95 aislamientos clínicos obtenidos de tejidos normalmente estériles con infección invasiva por EGA. La pruebas de sensibilidad por difusión con discos de TMS fueron realizadas en agar Mueller Hinton adicionado ya sea con 5% de sangre de carnero (MH-SC) o con 5% de sangre equina lisada (MH-SEL). La sangre equina lisada contiene timidina fosforilasa, que degrada este nucleósido. Como método de referencia se utilizó la epsilometría (Etest). El control de calidad con la cepa Enterococcus faecalis ATCC 29212 fue satisfactorio para ambos medios. La sensibilidad a TMS por difusión fue 100% en MH-SEL; en agar MH-SC 6 (6.3%) aislamientos resultaron resistentes; por Etest todos fueron sensibles, excepto uno de esos seis que presentó sensibilidad intermedia (CIM = 1.5/28.5 μg/ml). En este aislamiento no se encontraron las mutaciones genéticas de EGA más frecuentemente asociadas a resistencia a TMS. Probablemente, si se establecieran mejores puntos de corte para difusión, específicos para EGA, podría optimizarse la correlación con métodos de dilución o con Etest, aun empleando MH-SC.

It is erroneously believed that group A streptococci (GAS) are universally resistant to trimethoprim-sulfamethoxazole (TMS). This is mainly because media commonly used for in vitro determination of susceptibility to antibiotics contain thymidine, a nucleoside that antagonizes the antibiotic effect of TMS. The objective of this work was to determine EGA sensitivity to TMS in the presence and absence of thymidine. To this aim, 95 GAS isolates obtained from clinical tissues with i nvasive infections were analyzed. Susceptibility tests were performed by diffusion with TMS discs in Mueller Hinton agar supplemented either with 5% sheep blood or with 5% lysed equine blood (MH-LEB). Lysed equine blood contains thymidine phosphorylase, which degrades this nucleoside. Epsilometry (Etest) was used as gold standard. Quality controls with Enterococcus faecalis strain ATCC 29212 were satisfactory with both media. A 100% sensitivity to TMS was found in MH-SEL whereas 6 isolates (6.3%) resulted resistant in MH-SC; only one of them was found to have intermediate susceptibility by Etest (MIC > 1.5/28 μg/ml). The genetic determinants most frequently associated to TMS resistant EGA were not found in this isolate. Probably, if more accurate GAS-specific cut-off points were established for diffusion, the correlation with dilution methods or with the Etest could be improved, even employing MH-SB.

Characterisation of OXA-258 enzymes and AxyABM efflux pump in Achromobacter ruhlandii.

OBJECTIVES: The aim of this study was to characterise OXA-258 variants and other features that may contribute to carbapenem resistance in Achromobacter ruhlandii. METHODS: Kinetic parameters for purified OXA-258a and OXA-258b were determined measuring the rate of hydrolysis of a representative group of antimicrobial agents. Whole-genome shotgun sequencing was performed on A. ruhlandii 38 (producing OXA-258a) and A. ruhlandii 319 (producing OXA-258b), and in silico analysis of antimicrobial resistance determinants was conducted. Substrates of the AxyABM efflux pump were investigated by inhibition assays using phenylalanine-arginine ß-naphthylamide (PAßN). Outer membrane protein profiles were resolved by 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). RESULTS: Kinetic measurements of purified OXA-258 variants displayed an overall weak catalytic efficiency toward ß-lactams. A detectable hydrolysis of imipenem was observed. In silico genomic analysis confirmed the presence of 32 and 35 putative efflux pump-encoding genes in A. ruhlandii strains 38 and 319, respectively. Complete sequences for AxyABM and AxyXY efflux pumps, previously described in Achromobacter xylosoxidans, were detected. Decreases in the MICs for chloramphenicol, nalidixic acid and trimethoprim/sulfamethoxazole were observed in the presence of the inhibitor PAßN, suggesting that these antibiotics are substrates of AxyABM. AxyXY-encoding genes of A. ruhlandii 38 and A. ruhlandii 319 displayed 99% identity. No differences were observed in the outer membrane protein profiles. CONCLUSIONS: The contribution of OXA-258 enzymes to the final ß-lactam resistance profile may be secondary. Further studies on other putative resistance markers identified in the whole-genome analysis should be conducted to understand the carbapenem resistance observed in A. ruhlandii.

Bacterias nosocomiales emergentes: Infección endovascular por Elizabethkingia meningoseptica / Emerging nosocomial bacteria: Endovascular infection by Elizabethkingia meningoseptica

Elizabethkingia meningoseptica es un bacilo gram negativo no fermentador, no móvil, y oxidasa positivo, ampliamente distribuido en la naturaleza pero poco frecuente en humanos, en quienes se considera un patógeno oportunista, actualmente denominado emergente. En el ambiente hospitalario se ha encontrado en superficies húmedas y en equipos médicos, soluciones que habitualmente se utilizan de forma intravenosa, y en medicamentos de reconstitución. Puede causar infección en personas inmunocomprometidas o con enfermedades debilitantes concomitantes. Además, posee enzimas de resistencia frente a los antibióticos prescritos usualmente contra las bacterias gram negativas. Se presenta un caso de bacteriemia por E. meningoseptica en un paciente con antecedente de enfermedad renal crónica, quien recibía tratamiento hemodíalítico 3 veces por semana, desde hace 2 años, al ingreso se documentó infección del sitio de inserción del catéter venoso central, y posteriormente se aisló en los hemocultivos periféricos el crecimiento de la bacteria E. meningoseptica, el paciente cumplió tratamiento con trimetroprim-sulfametoxazol por 14 días con adecuada evolución clínica, sin complicaciones...(AU)

Elizabethkingia meningoseptica is a non fermenter bacilli gram negative, non-mobile, and positive oxidase, widely distributed in nature but rare in humans, in whom it is considered an opportunistic pathogen, now called emerging. In the hospital environment it was found on wet surfaces and medical equipment, solutions usually used intravenously, and drug reconstitution. It can cause infection in immunocompromised or with concomitant debilitating diseases people. It also has resistance to enzymes usually prescribed antibiotics against gram negative bacteria. A case of bacteremia is presented by E. meningoseptica in a patient with a history of chronic kidney disease, who received hemodialysis 3 times a week, for 2 years, entry site infection insertion of central venous catheter was documented and later was isolated from peripheral blood cultures the growth of bacteria E. meningoseptica, the patient completed treatment with trimethoprim-sulfamethoxazole for 14 days with adequate clinical course without complications...(AU)

Effects of two 6-quinolinyl chalcones on the integrity of plasma membrane of Paracoccidioides brasiliensis.

Paracoccidioidomycosis is the most prevalent systemic mycosis in Latin America, yet few therapeutic options exist. Our aim was to search for new compounds with high efficacy, low toxicity, shorter treatment time and affordable cost. We studied two synthetic 6-quinolinyl chalcones, 3b and 3e, to determine their effects on VERO cells, antifungal activity, survival curve, interaction with other drugs and phenotypic effects against several isolates of Paracoccidioides spp. In this study, we verified that the compounds were not toxic, exhibited superior in vitro activity compared with that shown by trimethoprim-sulfamethoxazole, and after 5 days of treatment, decreased the fungal cell viability by approximately 70%. Additionally, no interactions were observed between the tested compounds and other drugs. We also found that these compounds induced morphological changes, such as shriveling of cells, fragmentation of the plasma membrane and cytoplasmic disorganization in vitro. The changes observed by microscopy assays corroborate the observation made with propidium iodide, where the number of cells stained with the compounds was higher than that observed after amphotericin B treatment. We observed an increase in the efflux of K+ and a loss of intracellular contents in cells treated with 3b and 3e, confirming their effects on fungal membranes. However, damage to the membrane was not associated with a decrease in membrane ergosterol levels. The experimental evidences showed no direct indications of cellular wall damage caused by these compounds. Thus, these results confirm the antifungal potential of 3b and 3e against Paracoccidioides spp. with possible action on the membrane.

High Prevalence of Pneumocystis jirovecii Dihydropteroate Synthase Gene Mutations in Patients with a First Episode of Pneumocystis Pneumonia in Santiago, Chile, and Clinical Response to Trimethoprim-Sulfamethoxazole Therapy.

Mutations in the dihydropteroate synthase (DHPS) gene of Pneumocystis jirovecii are associated with the failure of sulfa prophylaxis. They can develop by selection in patients receiving sulfa drugs or be acquired via person-to-person transmission. DHPS mutations raise concern about the decreasing efficacy of sulfa drugs, the main available therapeutic tool for Pneumocystis pneumonia (PCP). The prevalence of Pneumocystis DHPS mutations was examined in Pneumocystis isolates from 56 sulfa-prophylaxis-naive adults with a first episode of PCP from 2002 to 2010 in Santiago, Chile. Their clinical history was reviewed to analyze the effect of these mutations on response to trimethoprim-sulfamethoxazole (TMP-SMX) therapy and outcome. Mutant genotypes occurred in 22 (48%) of 46 HIV-infected patients and in 5 (50%) of 10 HIV-uninfected patients. Compared to patients with a wild-type genotype, those with mutant genotypes were more likely to experience sulfa treatment-limiting adverse reactions and to have a twice-longer duration of mechanical ventilation if mechanically ventilated. Specific genotypes did not associate with death, which occurred in none of the HIV-infected patients and in 50% of the non-HIV-infected patients. Chile has a high prevalence of DHPS mutations, which were presumably acquired through interhuman transmission because patients were not on sulfa prophylaxis. These results contrast with the low prevalence observed in other Latin American countries with similar usage of sulfa drugs, suggesting that additional sources of resistant genotypes may be possible. The twice-longer duration of mechanical ventilation in patients with mutant DHPS genotypes suggests a decreased efficacy of TMP-SMX and warrants collaborative studies to assess the relevance of DHPS mutations and further research to increase therapeutic options for PCP.

Escherichia coli clonal group A among uropathogenic infections in Mexico City.

Escherichia coli clonal group A (CGA) causes urinary tract and other extra-intestinal infections in humans. CGA is an important cause of trimethoprim/sulfamethoxazole (SXT) resistance in extra-intestinal pathogens. We examined the extent to which resistance in this area is related to CGA dissemination of E. coli from urinary tract infections (UTIs) in Mexico City. The virulence backgrounds of the isolates were also characterized. In this study, the frequency of resistance to SXT used for UTI treatment was high (56-65 %), and CGA isolates accounted for 9 of the 78 SXT-resistant isolates (11.5 %). Although all CGA isolates were found to be multidrug resistant (MDR), none of them were extended-spectrum ß-lactamase-producing organisms. The prevalence of CGA among the 45 MDR isolates that we identified was 20 %, indicating that this clonal group moderately contributes to the antibiotic resistance of uropathogenic E. coli isolates in this region. Most of the nine CGA isolates carried transferable, large-size plasmids of approximately 80 to 100 kb, which were able to transfer antimicrobial resistance to E. coli J53 in mating assays. CGA isolates mainly belonged to phylogenetic groups F and D. We found no association between antimicrobial resistance and virulence-associated genes: the median virulence scores of CGA isolates were slightly higher (4.6) than those of non-CGA isolates, whether they were susceptible (3.7) or resistant (3.5) to SXT. Our results indicate that CGA is not a major contributor to the high level of resistance to SXT in this region but, instead, seems to be an important constituent of MDR isolates from UTIs.

Diagnóstico y tratamiento del quiste del colédoco neonatal. Reporte de casos / Diagnosis and treatment strategy of neonatal choledochal cyst: Cases Report

Se reportan 2 casos de quiste de colédoco neonatal sintomáticos, uno de ellos con diagnóstico prenatal, que fueron llevados a tratamiento quirúrgico, realizando la resección de quiste del colédoco, derivación bilioentérica tipo hepático-yeyuno anastomosis en Y de Roux y colocación de drenaje de Penrose. En seguimiento de 20 meses en promedio con adecuada evolución.

We report two cases of symptomatc neonatal choledochal cysts, one of them prenatally diagnosed, who had surgical treatment with choledochal cyst resecton and Roux en Y hepato-jejunal anastomosis and Penrose drain. Follow up at 20 months (average) with good outcomes.

Streptococcus pneumoniae Serotypes 9 and 14 Circulating in Brazil over a 23-Year Period Prior to Introduction of the 10-Valent Pneumococcal Conjugate Vaccine: Role of International Clones in the Evolution of Antimicrobial Resistance and Description of a Novel Genotype.

Antimicrobial-resistant pneumococcal strains have been detected worldwide since the 1960s. In Brazil, the first penicillin-nonsusceptible pneumococci (PNSP) were reported in the 1980s, and their emergence and dissemination have been mainly attributed to serogroup 9 and serotype 14 strains, especially those highly related to recognized international clones. In the present study, antimicrobial susceptibility testing and multilocus sequence typing were performed on 315 pneumococcal isolates belonging to serogroup 9 (n = 99) or serotype 14 (n = 216), recovered from patients or asymptomatic carriers between 1988 and 2011 in Brazil, in order to trace changes in antimicrobial resistance and genotypes prior to the full introduction of the pneumococcal conjugate vaccine in the country. Over the 23-year study period, the PNSP levels increased, and four clonal complexes (CC156, CC66, CC15, and CC5401) have played important roles in the evolution and dissemination of pneumococcal isolates belonging to serogroup 9 and serotype 14, as well as in the emergence of antimicrobial resistance, in the pre-pneumococcal-vaccination era. The earliest PNSP strains detected in this study belonged to serotype 9N/ST66 and were single locus variants of the international clone Tennessee14-18 ST67 (CC66). The first serotype 14 PNSP isolates were identified in 1990 and were related to the England14-9 ST9 (CC15) clone. Serotype 14 PNSP variants of the Spain9V-3 ST156 clone with elevated penicillin MICs and nonsusceptibility to other beta-lactams were detected in 1995 and showed an increasing trend over the years. The results also indicated that introduction of ST156 in our region was preceded by the emergence of trimethoprim-sulfamethoxazole resistance and by the dissemination of ST162. In addition to the presence of successful international clones, a novel regional serotype 14 genotype (CC5401) has emerged in 1996.