Multidrug resistance genes, including blaKPC and blaCTX-M-2, among Klebsiella pneumoniae isolated in Recife, Brazil

INTRODUCTION: The prevalence of cephalosporins and carbapenem-resistant Klebsiella pneumoniae strains is rising in Brazil, with potential serious consequences in terms of patients' outcomes and general care. METHODS: This study characterized 24 clinical isolates of K. pneumoniae from two hospitals in Recife, Brazil, through the antimicrobial susceptibility profile, analyses of β-lactamase genes (blaTEM, blaSHV,blaCTX-MblaKPC, blaVIM, blaIMP, and blaSPM), plasmidial profile and ERIC-PCR (Enterobacterial repetitive intergenic consensus-polymerase chain reaction). RESULTS: ERIC-PCR and plasmidial analysis grouped the isolates in 17 and 19 patterns, respectively. Six isolates from one hospital presented the same pattern by ERIC-PCR, indicating clonal dissemination. All isolates presented blaSHV, 62.5% presented blaCTX-M-2, 29% blaTEM, and 41.7% blaKPC. Metallo-β-lactamase genes blaand blawere not detected. Eleven isolates were identified carrying at least 3 β-lactamase studied genes, and 2 isolates carried blaSHVblaTEM, blaCTX-M-2 and blaKPC simultaneously. CONCLUSIONS: The accumulation of resistance genes in some strains, observed in this study, imposes limitations in the therapeutic options available for the treatment of infections caused by K. pneumoniae in Recife, Brazil. These results should alert the Brazilian medical authorities to establish rigorous methods for more efficiently control the dissemination of antimicrobial resistance genes in the hospital environment.

Hemolytic and urease activities in vibrios isolated from fresh and frozen oysters

INTRODUCTION: The present study aimed to survey the Vibrio microbiota of oysters (Crassostrea rhizophorae) obtained from restaurants in Fortaleza, State of Ceará, Brazil, and to identify virulence factors. METHODS: The isolated vibrios were submitted to biochemical identification and were tested for hemolytic and urease activities. RESULTS: The isolated strains belonged to 13 species, with predominance of Vibrio mimicus. Of the strain isolates only from fresh samples, 20.5% and 2.8% showed hemolytic and urease activities, respectively. CONCLUSIONS: The findings support the little-publicized claim that Vibrio species other than V. parahaemolyticus and V. vulnificus can represent a health risk to public health.

Susceptibility to amphotericin B of Candida spp. strains isolated in Ceará, Northeastern Brazil

IntroductionAmphotericin B (AMB) is an antifungal agent used extensively in clinical medicine, yet resistance remains low. This study aims to evaluate the susceptibility of Candida spp. against AMB.MethodsFor broth microdilution susceptibility testing, 77 strains of Candida spp. were selected (32 C. albicans, 33 C. tropicalis, and 12 C. parapsilosis). The strains were considered susceptible when they exhibited MIC≤1.0µg/ml.ResultsNone of the strains showed an MIC greater than 0.25µg/ml.ConclusionsFurther works are necessary, with a higher number of strains, to assess the validity of the results used in this study.

Molecular and biological characterization of Trypanosoma cruzi strains isolated from children from Jequitinhonha Valley, State of Minas Gerais, Brazil

Introduction The biological diversity of Trypanosoma cruzi strains plays an important role in the clinical and epidemiological features of Chagas disease. Methods Eight T. cruzi strains isolated from children living in a Chagas disease vector-controlled area of Jequitinhonha Valley, State of Minas Gerais, Brazil, were genetically and biologically characterized. Results The characterizations demonstrated that all of the strains belonged to T. cruzi II, and showed high infectivity and a variable mean maximum peak of parasitemia. Six strains displayed low parasitemia, and two displayed moderate parasitemia. Later peaks of parasitemia and a predominance of intermediate and large trypomastigotes in all T. cruzi strains were observed. The mean pre-patent period was relatively short (4.2±0.25 to 13.7±3.08 days), whereas the patent period ranged from 3.3±1.08 to 34.5±3.52 days. Mortality was observed only in animals infected with strain 806 (62.5%). Histopathological analysis of the heart showed that strains 501 and 806 caused inflammation, but fibrosis was observed only in animals infected with strain 806. Conclusions The results indicate the presence of an association between the biological behavior in mice and the genetic characteristics of the parasites. The study also confirmed general data from Brazil where T. cruzi II lineage is the most prevalent in the domiciliary cycle and generally has low virulence, with some strains capable of inducing inflammatory processes and fibrosis.

Phenotypic detection of metallo-β-lactamases in Pseudomonas aeruginosa and Acinetobacter baumannii isolated from hospitalized patients in São Luis, State of Maranhão, Brazil

Introduction Acquired metallo-β-lactamases (MβL) are emerging determinants of resistance in Pseudomonas aeruginosa and Acinetobacter baumannii. The objectives of this study were to phenotypically detect MβL in imipenem-resistant P. aeruginosa and A. baumannii, to investigate the association between MβL-positive strains and hospitals, and to compare the resistance profiles of MβL-producing and non-MβL-producing strains. Methods The approximation disk and combined disk assay methods were used in this study. Results A total of 18 (38.3%) P. aeruginosa isolates and 1 (5.6%) A. baumannii isolate tested positive for the presence of MβL. Conclusions These results demonstrate the need for strict surveillance and for the adoption of preventive measures to reduce the spread of infection and potential outbreaks of disease caused by MβL-producing microorganisms.

Effects of Rosmarinus officinalis essential oil on germ tube formation by Candida albicans isolated from denture wearers

Introduction The aim of this study was to investigate the effects of Rosmarinus officinalis essential oil on germ tube formation by Candida albicans isolated from denture wearers. Methods Ten C. albicans isolates recovered from denture wearers were tested using 10% fetal bovine serum with or without 4% R. officinalis essential oil. Results The essential oil from R. officinalis completely inhibited germ tube formation in the investigated C. albicans isolates. Conclusions The results demonstrate that the essential oil of R. officinalis modulates C. albicans pathogenicity through its primary virulence factor (i.e., germ tube formation was suppressed).

Production of metallo-β-lactamase among Pseudomonas aeruginosa strains isolated in the State of Sergipe, Brazil

INTRODUCTION: Acquired production of metallo-β-lactamases is an important mechanism of resistance in Pseudomonas aeruginosa. The objective of this study was to investigate the production of metallo-β-lactamase and the genetic diversity among ceftazidime-resistant P. aeruginosa isolates from State of Sergipe, Brazil. METHODS: Metallo-β-lactamase was investigated using the disk approximation test and polymerase chain reaction (PCR). Genetic diversity was evaluated by pulsed-field gel electrophoresis (PFGE). RESULTS: A total of 48 (51.6%) isolates were resistant to ceftazidime. Six (12.2%) of these were positive for metallo-β-lactamase production. Only two (4.1%) of the ceftazidime-resistant isolates carried the bla SPM-1 gene. CONCLUSIONS: Production of metallo-β-lactamases was not the main mechanism of resistance to ceftazidime and carbapenems among P. aeruginosa strains in Sergipe, Brazil.

Molecular identification and antifungal susceptibility profiles of Candida parapsilosis complex species isolated from culture collection of clinical samples

AbstractINTRODUCTION:Candida parapsilosis is a common yeast species found in cases of onychomycosis and candidemia associated with infected intravascular devices. In this study, we differentiated Candida parapsilosis sensu stricto, Candida orthopsilosis , and Candida metapsilosis from a culture collection containing blood and subungual scraping samples. Furthermore, we assessed the in vitro antifungal susceptibility of these species to fluconazole, itraconazole, voriconazole, posaconazole, amphotericin B, and caspofungin.METHODS:Differentiation of C. parapsilosis complex species was performed by amplification of the secondary alcohol dehydrogenase (SADH) gene and digestion by the restriction enzyme Ban I. All isolates were evaluated for the determination of minimal inhibitory concentrations using Etest, a method for antifungal susceptibility testing.RESULTS:Among the 87 isolates, 78 (89.7%) were identified as C. parapsilosis sensu stricto , five (5.7%) were identified as C. orthopsilosis , and four (4.6%) were identified as C. metapsilosis . Analysis of antifungal susceptibility showed that C. parapsilosis sensu strictoisolates were less susceptible to amphotericin B and itraconazole. One C. parapsilosis sensu stricto isolate was resistant to amphotericin B and itraconazole. Moreover, 10.2% of C. parapsilosis sensu stricto isolates were resistant to caspofungin. Two C. parapsilosis sensu strictoisolates and one C. metapsilosis isolate were susceptible to fluconazole in a dose-dependent manner.CONCLUSIONS:We reported the first molecular identification of C. parapsilosiscomplex species in State of Goiás, Brazil. Additionally, we showed that although the three species exhibited differences in antifungal susceptibility profiles, the primary susceptibility of this species was to caspofungin.

Pharmacokinetic/pharmacodynamic target attainment of intravenous β-lactam regimens against Gram-negative bacteria isolated in a Brazilian teaching hospital

ABSTRACTINTRODUCTION: Monte Carlo simulations have been used for selecting optimal antibiotic regimens for treatment of bacterial infections. The aim of this study was to assess the pharmacokinetic and pharmacodynamic target attainment of intravenous β-lactam regimens commonly used to treat bloodstream infections (BSIs) caused by Gram-negative rod-shaped organisms in a Brazilian teaching hospital.METHODS: In total, 5,000 patients were included in the Monte Carlo simulations of distinct antimicrobial regimens to estimate the likelihood of achieving free drug concentrations above the minimum inhibitory concentration (MIC; fT > MIC) for the requisite periods to clear distinct target organisms. Microbiological data were obtained from blood culture isolates harvested in our hospital from 2008 to 2010.RESULTS: In total, 614 bacterial isolates, including Escherichia coli, Enterobacterspp., Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, were analyzed Piperacillin/tazobactam failed to achieve a cumulative fraction of response (CFR) > 90% for any of the isolates. While standard dosing (short infusion) of β-lactams achieved target attainment for BSIs caused by E. coliand Enterobacterspp., pharmacodynamic target attainment against K. pneumoniaeisolates was only achieved with ceftazidime and meropenem (prolonged infusion). Lastly, only prolonged infusion of high-dose meropenem approached an ideal CFR against P. aeruginosa; however, no antimicrobial regimen achieved an ideal CFR against A. baumannii.CONCLUSIONS:These data reinforce the use of prolonged infusions of high-dose β-lactam antimicrobials as a reasonable strategy for the treatment of BSIs caused by multidrug resistant Gram-negative bacteria in Brazil.

Hydatid cysts in muscles: clinical manifestations, diagnosis, and management of this atypical presentation

ABSTRACTINTRODUCTION: Hydatid cysts are rarely detected in muscle tissue (0.7-0.9%), even in endemic countries. The aim of this study was to present information regarding the clinical manifestations, diagnosis, and management of muscle echinococcosis.METHODS: Twenty-two patients with hydatid cysts in the muscle were followed from January 2006 through December 2014.RESULTS: Twenty-four sites of muscle involvement were observed in the 22 patients. Fifteen (68%) of our patients were women, while seven (32%) were men. The mean age was 28.1 ± 15.4 (6-61) years. The most frequent locations were the thigh (27.2%) and the paravertebral region (13.6%). Most patients reported a painless slow-growing mass with normal overlying skin. Most (90.2%) cases were treated by surgical excision and fine-needle aspiration.CONCLUSIONS: Primary muscle hydatid cyst should be considered in the differential diagnosis in cystic masses of the muscular system without pain and localized enlargement of soft tissue, especially in endemic areas. Hydatid cyst should be investigated using serological tests and imaging modalities. If possible, total surgical excision of hydatid cyst in the muscle should be performed.

Antimicrobial resistance profiles and oxacillinase genes in carbapenem-resistant Acinetobacter baumannii isolated from hospitalized patients in Santa Catarina, Brazil

Abstract: INTRODUCTION: Carbapenems are the therapy of choice for treating severe infections caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii complex. We aimed to assess the prevalence and antimicrobial susceptibility profiles of producers of distinct oxacillinases among nosocomial isolates of the A. calcoaceticus-A. baumannii complex in a 249-bed general hospital located in Joinville, Southern Brazil. METHODS: Of the 139 A. baumannii clinical isolates with reduced susceptibility to carbapenems between 2010 and 2013, 118 isolates from varying anatomical sites and hospital sectors were selected for genotypic analysis. Five families of genes encoding oxacillinases, namely blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, blaOXA-58-like, and blaOXA-143-like, wereinvestigated by multiplex polymerase chain reaction (PCR). RESULTS: Most (87.3%) isolates simultaneously carried the blaOXA-23-likeand blaOXA-51-likegenes, whereas three (2.5%) isolates harbored only blaOXA-51-likeones. The circulation of carbapenem-resistant isolates increased during the study period: from none in 2010, to 22 in 2011, 64 in 2012, and 53 in 2013. CONCLUSIONS: Isolates carrying the blaOXA-23-likeand blaOXA-51-likegenes were widely distributed in the hospital investigated. Because of the worsening scenario, the implementation of preventive measures and effective barriers is needed.

Monoterpene isolated from the essential oil of Trachyspermum ammi is cytotoxic to multidrug-resistant Pseudomonas aeruginosa and Staphylococcus aureus strains

Abstract INTRODUCTION: The aim of this study was to determine whether an herbal extract containing monoterpene exhibited activity against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa isolated from clinical infection samples. METHODS: The essential oil of Trachyspermum ammi (L.) Sprague ex Turrill (Apiaceae) fruit was extracted by hydrodistillation. Fruit residues were treated with hydrochloric acid and re-hydrodistilled to obtain volatile compounds. Compounds in the distilled oil were identified using gas-chromatography (GC) and GC-mass spectrometry (MS). The antibiotic susceptibility of all bacterial isolates was analyzed using both the disc diffusion method and determination of the minimum inhibitory concentration (MIC). The sensitivity of antibiotic-resistant isolates to essential oil was also determined by using the disc diffusion method and MIC determination. RESULTS: Of 26 clinical isolates, 92% were multidrug-resistant (MDR). Aromatic monoterpenes (thymol, paracymene, and gamma-terpinene) were the major (90%) components of the oil. Growth of S. aureus strains was successfully inhibited by the oil, with an inhibitory zone diameter (IZD) between 30-60mm and MIC <0.02μL/mL. The oil had no antimicrobial activity against clinical isolates of P. aeruginosa; rather, it prevented pigment production in these isolates. CONCLUSIONS: This study revealed that the essential oil of Trachyspermum ammi, which contains monoterpene, has good antibacterial potency. Monoterpenes could thus be incorporated into antimicrobial ointment formulas in order to treat highly drug-resistant S. aureus infections. Our findings also underscore the utility of research on natural products in order to combat bacterial multidrug resistance.

Secular trends in Klebsiella pneumoniae isolated in a tertiary-care hospital: increasing prevalence and accelerated decline in antimicrobial susceptibility

Abstract: INTRODUCTION Klebsiella pneumoniae has become an increasingly important etiologic agent of nosocomial infections in recent years. This is mainly due to the expression of virulence factors and development of resistance to several antimicrobial drugs. METHODS This retrospective study examines data obtained from the microbiology laboratory of a Brazilian tertiary-care hospital. To assess temporal trends in prevalence and antimicrobial susceptibility, K. pneumoniae isolates were analyzed from 2000 to 2013. The relative frequencies of K. pneumoniae isolation were calculated among all Gram-negative bacilli isolated in each period analyzed. Susceptibility tests were performed using automated systems. RESULTS: From 2000-2006, K. pneumonia isolates comprised 10.7% of isolated Gram-negative bacilli (455/4260). From 2007-2013, this percentage was 18.1% (965/5331). Strictly considering isolates from bloodstream infections, the relative annual prevalence of K. pneumoniae increased from 14-17% to 27-32% during the same periods. A progressive decrease in K. pneumoniae susceptibility to all antimicrobial agents assessed was detected. Partial resistance was also observed to antimicrobial drugs that have been used more recently, such as colistin and tigecycline. CONCLUSIONS Our study indicates that K. pneumoniae has become a major pathogen among hospitalized patients and confirms its recent trend of increasing antimicrobial resistance.

Trypanosoma cruzi isolated from a triatomine found in one of the biggest metropolitan areas of Latin America

Abstract: INTRODUCTION: To characterize Trypanosoma cruzi (TcI) isolated from a Panstrongylus megistus specimen found in one of the biggest metropolitan areas of Latin America, the relationship between the TcI group of T. cruzi and the transmission cycle in the urban environment was studied. METHODS: The T. cruzi strain, Pm, was isolated in a culture medium from the evolutionary forms present in the hindgut of a live male specimen of P. megistus found in the Jabaquara subway in São Paulo City. The sample from the triatomine showed trypomastigote forms of Trypanosomatidae, which were inoculated in the peritoneum of Balb/c mice. The sample was then inoculated in Liver Infusion Tryptose medium and J774 cells for the molecular identification and characterization of the parasite. The Pm strain of T. cruzi was identified by isolation in axenic culture medium, and based on the morphology, cell infection, growth kinetics, and molecular characterization. RESULTS: After isolation, the protozoan was identified as T. cruzi. No parasites were detected in the peripheral blood of the animal, which can be a characteristic inherent to the strain of T. cruzi that was isolated. Cell invasion assays were performed in triplicate in the J774 cell line to confirm the invasive ability of the Pm strain and revealed amastigote forms of the parasite within macrophages. CONCLUSIONS: Our biological and molecular characterizations helped understand parasite-host interactions and their evolutionary history in context of the associations between vectors, ecotopes, hosts, and groups of the parasite.

Small mammal abundances in isolated and non-isolated primary forest reserves near Manaus, Brazil

Abundances of msmall terrestrial mammals were estimated in 10 and 100-ha, isolated and non-isolated primary forest reserves near, Manaus, Brazil between October 1983 and March 1984. The smalt mammal abundance pattern In a 10 ha reserve isolated fan appoximately three years differed significantly from that in othen reserves, primarily due to higher capture rates of Marmosa cinerea, Rhipidomys mastacalis, and Onyzomys paricola in the isolated reserve. Viet type and re-invasion potential may be important factors the small mammal communities in forest patches. Variation the small mammal community among othen reserves was pnimanlty due to variatton In the abundances of Proechimys and 0. capito. At least pant of this vantation was attributable to temporal efects, but variation due to reserve effects also was suggested. Small mammals were much more abundant in the reserves during the present study than in 1982.