In Silico Modeling and Docking Analysis of CTX-M-5, Cefotaxime-Hydrolyzing ?-Lactamase from Human-Associated Salmonella Typhimurium

Objective: To computationally model the CTX-M-5 ?-lactamase and establish its structure, which is exclusively present in human-associated Salmonella. Methods: The CTX-M-5 aminoacid sequence (Uniprot ID:O65975) of Salmonella enterica subsp. enterica serovar typhimurium was retrieved from UniProt database and subjected to homology modeling using MODELLER 9v7. The homology models were duly validated using RAMPAGE tool by generating Ramachandran plots, ERRAT graphs, and ProSA score. DoGSiteScorer server and ConSurf server were used to detect the cavities, pockets, and clefts to identify conserved amino acid sites in the predicted model. Subsequently, the modeled structure was docked using CLC Drug Discovery Workbench against proven drugs and known inhibitors. Results: Obtained high-quality homology model with 91.7% of the residues in favorable regions in Ramachandran plot and qualified in other quality parameters. Docking studies resulted in a higher dock score for PNK (D-benzylpenicilloic acid) molecule when compared to other reported inhibitors. Conclusion: This in silico study suggests that the compound PNK could be an efficient ligand for CTX-M-5 ?-lactamase and serve as a potent inhibitor of CTX-M-5.

Detection of beta-lactamase-producing Enterobacteriaceae in a veterinary hospital environment / Detecção de Enterobactérias produtoras de beta-lactamases em ambiente hospitalar veterinário

Due to the strong selective pressure resulting from the misuse of antibiotics, the natural process of bacterial resistance has been accelerated, leading to the increasingly constant appearance of multiresistant isolates. The high number of multi-resistant bacteria is a one health problem. Enterobacteriaceae are usually commensal bacteria of the gastrointestinal tract. However, they can cause infections, and the most important resistance characteristic among them is the production of ß-lactamases. This study aimed to identify ESBL-producing Enterobacteriaceae of types of TEM, SHV, and the CTX-Mgroups. To isolate the enterobacteria, swabs were collected by swiping objects that had contact with the patients and professionals, and the water of the hospital environment. Ten collections were carried out, yielding 306 samples, from which 118 enterobacteria were identified: Escherichia coli, Enterobacter spp., Klebsiella spp., Proteus mirabilis, Serratiaspp., and Citrobacter spp. Isolates. The genes TEM and CTX-M, for the production of ß-lactamases, were detected in 12.7% of the 118 enterobacterial isolates. It is very important to know the bacterial population circulating in the veterinary hospital environment and its resistance to antimicrobials so that professionals can take appropriate measures to minimize the risks of transmission, especially from cages and consultation tables. In addition, the correct control of the microbiological quality of the supply water, as well as environmental cleaning procedures, are essential to prevent the transmission of these microorganisms.(AU)

Devido à grande pressão seletiva decorrente do uso indevido de antibióticos, tem se acelerado o processo natural de resistência das bactérias, levando ao aparecimento cada vez mais constante de isolados multirresistentes. O elevado número de bactérias multirresistentes identificadas é um problema da saúde única. As enterobactérias são bactérias geralmente comensais do trato gastrointestinal, entretanto podem causar infecções, e a característica de resistência mais importante entre elas é a produção de ß-lactamases. Buscando caracterizar melhor os microrganismos circulantes e potencialmente causadores de infecções em ambiente hospitalar veterinário, este estudo objetivou identificar as enterobactérias produtoras de ESBL do tipo TEM, SHV e os cinco grupos de CTX-M presentes em isolados circulantes em hospital veterinário. Foi realizada coleta de suabes de arrasto de objetos que entram em contato com os pacientes e com os profissionais que ali trabalham, bem como de água, para a identificação das enterobactérias. Foram realizadas 10 coletas, obtendo-se 306 amostras, dessas, 118 enterobactérias foram identificadas: Escherichia coli, Enterobacter, Klebsiella, Proteus mirabilis, Serratia e Citrobacter. Dentre as enterobactérias identificadas, alguns isolados possuíam genes para a produção de ß-lactamases, do tipo TEM e CTX-M. É de grande importância conhecer a população bacteriana circulante no ambiente hospitalar veterinário, e a sua resistência aos antimicrobianos, para que os profissionais possam tomar medidas apropriadas para minimizar os riscos de transmissão, principalmente a partir de gaiolas e mesas de atendimento. Além disso, o correto controle da qualidade microbiológica da água de abastecimento, bem como dos procedimentos de higienização do ambiente, são fundamentais para evitar a transmissão destes microrganismos.(AU)

MDR Escherichia coli carrying CTX-M-24 (IncF[F-:A1:B32]) and KPC-2 (IncX3/IncU) plasmids isolated from community-acquired urinary trainfection in Brazil

ABSTRACT Acquired antibiotic resistance in bacteria has become an important worldwide challenge. Currently, several bacteria, including Escherichia coli, have multidrug resistance profiles. Genes such as bla CTX-M-24 and bla KPC-2 (carbapenemase) are widespread. This research letter reports about a genomic surveillance study where multidrug-resistant E. coli containing CTX-M-24(IncF [F-:A1:B32]) and KPC-2(IncX3/IncU) plasmids were obtained from community- acquired urinary tract infection in Brazil.

A facile and universal method to achieve liposomal remote loading of non-ionizable drugs with outstanding safety profiles and therapeutic effect

Liposomes have made remarkable achievements as drug delivery vehicles in the clinic. Liposomal products mostly benefited from remote drug loading techniques that succeeded in amphipathic and/or ionizable drugs, but seemed impracticable for nonionizable and poorly water-soluble therapeutic agents, thereby impeding extensive promising drugs to hitchhike liposomal vehicles for disease therapy. In this study, a series of weak acid drug derivatives were designed by a simplistic one step synthesis, which could be remotely loaded into liposomes by pH gradient method. Cabazitaxel (CTX) weak acid derivatives were selected to evaluate regarding its safety profiles, pharmacodynamics, and pharmacokinetics. CTX weak acid derivative liposomes were superior to Jevtana® in terms of safety profiles, including systemic toxicity, hematological toxicity, and potential central nerve toxicity. Specifically, it was demonstrated that liposomes had capacity to weaken potential toxicity of CTX on cortex and hippocampus neurons. Significant advantages of CTX weak acid derivative-loaded liposomes were achieved in prostate cancer and metastatic cancer therapy resulting from higher safety and elevated tolerated doses.

Anti-ENO1 antibody combined with metformin reverses the resistance of human non-small cell lung cancer A549 cells to cetuximab by targeting cancer stem cells / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To explore the effect of anti-ENO1 (enolase 1) antibody and metformin (MET) treatment on the proliferation, migration, invasion and stemness of cetuximab (CTX) -resistant non-small cell lung cancer (NSCLC) cells through targeting cancer stem cells and the possible mechanism. Methods: 10 mmol/L MET combined with 40 μg/ml anti-ENO1 antibody was used to treat CTX(35 µg/ml)-resistant NSCLC A549 cells for 4 d, and the effects of combined treatment on A549 cells were detected with proliferation experiment, colony formation assay, migration and invasion experiments and methylcellulose ball formation experiment. In the meanwhile, FCM was used to detect the effects of CTX, MET and anti-ENO1 antibody single-drug treatment as well as the three-drug combination treatment on ALDH+ and CD44+ lung cancer stem cell subsets. Results: CTX combined with MET and anti-ENO1 antibody treatment significantly inhibited the proliferation, migration, invasion and self-renewal capacity of A549 cells. FCM analysis found that MET could significantly inhibit ALDH+ stem cell subpopulations, while anti-ENO1 antibody could significantly inhibit CD44+ stem cell subpopulations, and the three-drug combination treatment could simultaneously suppress ALDH+ and CD44+ stem cell subpopulations. Conclusion: MET and anti-ENO1 antibody respectively target ALDH+ and CD44+ cancer stem cell subsets, and the combined treatment of MET and anti-ENO1 antibody can effectively reverse the resistance of A549 cells to CTX, and thereby more effectively inhibiting stemness, proliferation, metastasis of A549 cells and tumor recurrence.

Prevalence Of Ctx-M-Producing Gram-Negative Uropathogens In Sokoto, North-Western Nigeria

Objective: Infections of the urinary tract remains one of the most common bacterial infections with many implicated organisms being Gram-negative, which are increasingly resistant to antimicrobial agents. The aim of the study was to evaluate the resistance of ESBL producing Gram-negative enterobacteriaceae to commonly prescribed antibiotics and the prevalence of CTX-M genes from these isolates using polymerase chain reaction (PCR). Methods: The isolates were collected from urine over a period of 4 mo and studied, and were identified using Microgen Identification Kit (GN-ID). Susceptibility testing was performed by the modified Kirby Bauer disc diffusion method, and results were interpreted according to Clinical and Laboratory Standard Institute (CLSI). Extended-Spectrum Beta-Lactamase (ESBL) production was detected by the double-disc synergy test (DDST). Molecular characterization was based on the isolates that were positive for the phenotypic detection of ESBL. Results: Sixty one (61) isolates of Gram-negative uropathogens were identified. Of these, 19 (31.2%) were E. coli, 15 (24.6%) were Salmonella arizonae, Klebsiella pneumoniae were 7 (11.5%), Klebsiella oxytoca were 3 (4.9%), Enterobacter gergoviae were 6 (9.8%), 4 (6.6%) were Citrobacter freundii, 4 (6.6%) were Serratia marscence, and 1 (1.6%) were Enterobacter aerogenes, Proteus mirabilis, and Edwardsiella tarda each. Analysis of the bacterial susceptibility to antibiotics revealed most of them to be generally resistant to cotrimoxazole (73.3%), nalidixic acid (66.7%), norfloxacin (53.5%), ciprofloxacin (50.5%), gentamicin (48.6%), amoxicillin/clavulanate (45%), and the least resistant was displayed in nitrofurantoin (30%). Of the 15 ESBL producers, 11 (73.3%) were harbouring bla CTX-M genes. Conclusion: The study revealed a high susceptibility to nitrofurantoin, whereas susceptibility to cotrimoxazole was lowest. It further portrays a high prevalence of enterobacteriaceae isolates harbouring bla CTX-M genes in Sokoto metropolis.

Detección de los genes de ß-lactamasas blaTEM, blaSHV y blaCTX-M en aislamientos de Escherichia coli comunitarios / Detection of ß-lactamase genes bla TEM, bla SHV and bla CTX-M in community isolates of Escherichia coli

A nivel mundial la resistencia a los antibióticos es un problema de salud pública, tanto en el ámbito hospitalario como en el comunitario. La producción de ß-lactamasas es el principal mecanismo de resistencia en enterobacterias y la mayoría de enzimas responsables pertenecen a las familias TEM, SHV y CTX-M. El objetivo de este estudio fue detectar los genes de ß-lactamasas blaTEM, blaSHV y blaCTX-M en cepas comunitarias de Escherichia coli productoras de BLEE aisladas de urocultivos de pacientes que acudieron al Laboratorio Clínico Popular de la Universidad de San Carlos de Guatemala en el año 2016. Se detectó la presencia de al menos uno de los genes en el 90% de los 79 aislamientos y un 53.2% presentó los tres genes. La frecuencia fue de 57% para blaCTX-M, 84% para bla SHV y 85% para blaTEM. La detección de los genes codificadores de las enzimas TEM-1, SHV-11, CTX-M15 y CTX-M55 corresponde a la primera caracterización molecular de aislamientos de E. coli productoras de BLEE en Guatemala y son importantes para entender su propagación en el ámbito comunitario. Los aislamientos de E. coli productoras de BLEE mostraron alta resistencia a ciprofloxacina y trimetoprim sulfametoxazol (78%) y bajos niveles de resistencia para fosfomicina (2.5%) y nitrofurantoina (7.6%). El 11.39% de las cepas presentó resistencia a un grupo de antibióticos no betalactámicos. Es importante establecer una vigilancia activa para la resistencia de estos antibióticos en cepas comunitarias ya que son la primera opción de tratamiento para cepas productoras de BLEE

Globally, resistance to antibiotics is a public health problem, both in the hospital and in the community environment. e production of ß-lactamases is the main mechanism of resistance in enterobacteria and usually the cause of resistance are the enzymes to the families TEM, SHV and CTX-M. e principal aim of this study was to detect - ß-lactamase genes blaTEM, blaSHV and blaCTX-M in community strains of ESBL-producing Escherichia coli isolated from urine cultures of patients attended in the Laboratorio Clínico Popular of the Universidad de San Carlos de Guatemala in 2016. At least, one of the genes was detected in 90% of the 79 isolates and in 53.2% of the isolates the three genes were detected. e frequency was 57% for blaCTX-M, 84% for blaSHV and 85% for blaTEM. e detection of the genes coding for TEM-1, SHV-11, CTX-M15 and CTX-M55 represent the first molecular characterization of ESBL-producing E. coli isolates in Guatemala and it is important to understand the spread of these strains at the community environment. e ESBL-producing E. coli isolates showed high resistance to ciprofloxacin and trimethoprim sulfamethoxazole (78%) and low resistance levels for fosfomycin (2.5%) and nitrofurantoin (7.6%). e 11.39% of the strains showed resistance to a group of non-beta-lactam antibiotics. It is important to establish an active surveillance for these antibiotics in community strains because they are the first line treatment for strains producing ESBL

High prevalence of CTX-M-1 group in ESBL-producing enterobacteriaceae infection in intensive care units in southern Chile

ABSTRACT Enterobacteria-producing extended-spectrum β-lactamases (ESBL) play an important role in healthcare infections, increasing hospitalization time, morbidity and mortality rates. Among several ESBLs that emerge from these pathogens, CTX-M-type enzymes had the most successful global spread in different epidemiological settings. Latin America presents high prevalence of CTX-M-2 in ESBL-producing enterobacterial infections with local emergence of the CTX-M-1 group. However, this high prevalence of the CTX-M-1 group has not yet been reported in Chile. The aim of this study was to identify ESBLs among enterobacteria isolated from clinical samples of critically ill patients from southern Chile. One-hundred thirty seven ESBL-producing bacteria were isolated from outpatients from all critical patient units from Hernán Henríquez Aravena Hospital. Phenotype characterization was performed by antibiogram, screening of ESBL, and determination of minimum inhibitory concentration (MIC). PCR was used for genetic confirmation of resistance. Molecular typing was performed by ERIC-PCR. ESBL-producing isolates were identified as Klebsiella pneumoniae (n = 115), Escherichia coli (n = 18), Proteus mirabilis (n = 3), and Enterobacter cloacae (n = 1), presenting multidrug resistance profiles. PCR amplification showed that the strains were positive for blaSHV (n = 111/81%), blaCTX-M-1 (n = 116/84.7%), blaTEM (n = 100/73%), blaCTX-M-2 (n = 28/20.4%), blaCTX-M-9 (0.7%), blaPER-1 (0.7%), and blaGES-10 (0.7%). The multiple production of ESBL was observed in 93% of isolates, suggesting high genetic mobility independent of the clonal relationship. The high frequency of the CTX-M-1 group and a high rate of ESBL co-production are changing the epidemiology of the ESBL profile in Chilean intensive care units. This epidemiology is a constant and increasing challenge, not only in Chile, but worldwide.

CTX-M type extended-spectrum ?-lactamase in Escherichia coli isolated from extra-intestinal infections in a tertiary care hospital in south India

Background & objectives: Infections caused by extended-spectrum ?-lactamase (ESBL)-producing Escherichia coli carrying blaCTX-M genes have been spreading globally, but there are geographical variations in the type of blaCTX-Mgenes prevalent and there are scanty data from India. This study was conducted to determine the CTX-M type ESBLs in E. coli isolates obtained from clinical specimens from patients with extra-intestinal infections attending a tertiary care hospital in south India. Methods: ESBL-producing E. coli isolated from patients with extra-intestinal infections were subjected to PCR using CTX-M group-specific primers. From a representative isolate, full-length CTX-M-15 gene was amplified and sequenced. An internal fragment of this gene was sequenced in 10 representative isolates. Results: Of the 300 isolates of E. coli tested, 88 per cent carried CTX-M genes and blaCTX-M-15was the most dominant gene present in 90 per cent of the positive isolates. Most (91%) of the isolates positive for blaCTX-M were sensitive to meropenem. Interpretation & conclusions: Our findings showed blaCTX-M-15 to be the dominant gene. Based on the data on antimicrobial susceptibility, cefoperazone-sulbactum could be an antimicrobial of choice.

Diversity of Genetic Environment of bla(CTX-M) Genes and Antimicrobial Susceptibility in Extended-spectrum β-lactamase producing Escherichia coli Isolated in Korea

Increasing resistance due to the production of extended-spectrum β-lactamase (ESBL) in Escherichia coli is a major problem to public health and CTX-M enzymes have become the most prevalent ESBL worldwide. In this study, resistance profiles of E. coli isolated in Korea and the genetic environments of bla(CTX-M) genes were analyzed by PCR and direct sequencing to clarify the mechanisms of spread of CTX-M. Resistance rates of CTX-M-producing E. coli, including β-lactams, fluoroquinolones and aminoglycosides, were significantly higher than that of CTX-M-non-producers (p<0.01). Of 41 tested, 39 (95.1%) isolates of CTX-M-producing E. coli showed resistance transfer by conjugation. All the transconjugants harboured large plasmids of 118~172 megadalton. Insertion sequence ISEcp1B was detected in the upstream of the bla(CTX-M) in 38 (92.7%) isolates with bla(CTX-M). ISEcp1B was disrupted by IS26 in 16 (39.0%) isolates with bla(CTX-M). ISEcp1B carried −35 and −10 promoter components between right inverted repeat (IRR) and the start codon of bla(CTX-M). orf477 or IS903D was observed in the downstream of the bla(CTX-M) in all the isolates with bla(CTX-M-3/15/55) or with bla(CTX-M-14/27), respectively. Sequence similar to IRR of ISEcp1B was located downstream of orf477. Target duplication sequences were detected both upstream of IRL and downstream of IRR. These results showed the involvement of ISEcp1B in the mobilization of the resistance genes. In conclusion, the surrounding DNAs of bla(CTX-M) genes were very diverse, and the spread and the expression of CTX-M may be deeply related with ISEcp1B. These informations will provide important knowledge to control the increase in CTX-M-ESBLs.

Association Between Toxin-antitoxin Systems on Plasmids and Persister Formation in CTX-15-producing Klebsiella pneumoniae ST11 Isolates

We investigated the effect of toxin-antitoxin (TA) systems in bla(CTX-M-15)-bearing plasmids of Klebsiella pneumoniae on persister formation. The persister formation rate was notably high in transconjugants in plasmids bearing TA system than the transconjugants in plasmids bearing no TA systems. Activation of relA and spoT expression was higher in transconjugants with plasmids bearing TA systems. Thus, TA systems in plasmids may contribute to the maintenance of bla(CTX-M-15)-bearing plasmids and host survival via persister formation.

Study on anti-fatigue, anti-oxidative and hemostatic effects of small molecule Asini Corii Colla / 中国药理学通报

Aim: To study the anti-fatigue,anti-oxidative and hemostatic effects of small molecule Asini Corii Colla (SMACC). Methods: Rat model of complex blood deficiency was established to detect the exhausted time of swimming, hematology, superoxide dismutase (SOD), serum maleic dialdehyde (MDA), and lipid peroxide (LPO) levels, aiming to explore the anti-fatigue and anti-oxidative effects of SMACC. ICR mice were used to measure the blood clotting time (CT) and bleeding time (BT). Fevered and bleeding model and the heparinized bleeding model in rats were established to investigate the effect of SMACC in hemostasis and its possible mechanism. Results: Compared with model group, SMACC significantly prolonged the swimming time of model rats (P < 0. 05, P < 0. 01) and decreased the content of serum MDA, LPO (P < 0.05,P<0.01) at doses of 1. 500,0. 750,0. 375 g. kg-1,and increased the number of lymphocytes in the blood at doses of 1. 500,0. 375 g. kg-1 (P <0. 05). SMACC of 3. 00,1.50 g kg-1 significantly reduced the BT and CT (P < 0. 05). SMACC markedly reversed the prolonged prothrombin time (P < 0. 05) and the adverse changes of the hematological indicators. Conclusions: SMACC has the pharmacological effects of anti-fatigue, anti-oxidation and enhancing endurance, and also the effects of hemostasis and convergence.

The Effects of Ficus Carica Fruit on Bone Markers and Oestrogen Level of Post-Menopausal Osteoporotic Rats

@#Introduction: Post-menopausal osteoporosis is the most common type of osteoporosis, which occurs due to a deficiency of oestrogen following menopause. Considering the adverse effects of oestrogen replacement therapy, natural products may serve to replace the current conventional treatment. Ficus carica (FC) which is commonly known as fig may have a potential in treating post-menopausal osteoporosis due to their abundance of important minerals and bioactive compounds such as phenolic, flavonoid and anthocyanins. This study aimed to evaluate the effects of FC on bone metabolism of ovariectomized rats. Materials and Methods: Fifty-six female Spraque-Dawley rats were randomly divided into seven groups; SHAM operated (SHAM), ovariectomized control (OVX), ovariectomized + 64.5 µg/kg oestrogen (ERT), ovariectomized + 50 mg/kg aqueous extract of FC (AQ50), ovariectomized + 100 mg/kg aqueous extract of FC (AQ100), ovariectomized + 50 mg/kg raw FC (RW50), and ovariectomized + 100 mg/kg raw FC (RW100). After eight weeks of treatments, rats were euthanized and femurs were dissected out to measure bone osteocalcin, Ctelopeptide of type 1 collagen and bone estrogen level. Results: RW50 and RW100 showed an increasing trend in osteocalcin levels and also oestrogen level, but no significant difference between all groups. RW50 and RW100 also showed significantly reduced C-telopeptide of type 1 collagen levels compared to OVX group. Conclusion: These findings suggested that raw FC at the doses of 50 mg/kg and 100 mg/kg have potential to improve bone in treating post-menopausal osteoporosis. However, this need to be confirmed with higher doses.

Differences in Antimicrobial Resistance Phenotypes by the Group of CTX-M Extended-Spectrum β-Lactamase / 대한임상미생물학회지

BACKGROUND: Escherichia coli and Klebsiella pneumoniae clinical isolates producing CTX-M extendedspectrum β-lactamases (ESBLs) were assessed for antimicrobial resistance phenotypes varied by group of enzymes. METHODS: A total of 1,338 blood isolates, including 959 E. coli and 379 K. pneumoniae, were studied. All the strains were collected between January and July 2017 from eight general hospitals in South Korea. The species were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Antimicrobial susceptibilities were determined by disk diffusion methods and ESBL phenotypes by double-disk synergy tests using disks containing cefotaxime, ceftazidime, cefepime, aztreonam, and clavulanic acid (CA). The genes for β-lactamases were identified by PCR and sequencing. RESULTS: Of total microbes, 31.6% (303/959) E. coli and 24.0% (91/379) K. pneumoniae were resistant to cefotaxime and 28.1% (269/959) E. coli and 20.1% (76/379) K. pneumoniae were CTX-M-type ESBL producers. Among the detected CTX-M ESBLs, 58.0% (156/269) in E. coli and 86.8% (66/76) in K. pneumoniae belonged to group 1, 46.8% (126/269) in E. coli and 14.5% (11/76) in K. pneumoniae were group 9. Ten E. coli and one K. pneumoniae isolates co-produced both groups of CTX-M ESBL. The group 1 CTX-M producers had a higher level of resistance to cefotaxime, ceftazidime, cefepime, and aztreonam and exhibited stronger synergistic activities when combined with CA compared to group 9. CONCLUSION: ESBL phenotypes differ by CTX-M ESBL group and phenotype testing with drugs including 4th generation cephalosporins and monobactams is critical for screening CTX-M-producers with better sensitivity.

Evaluación de susceptibilidad y respuesta al tratamiento con piperacilina/tazobactam en pacientes con infecciones por Escherichia coli productoras de β -lactamasas de espectro extendido (BLEE) CTX-M / Evaluation of susceptibility and response to therapy with piperacillin-tazobactam in patients with infections caused by Escherichia coli with extended-spectrum β -lactamase (ESBL) CTX-M

Resumen Introducción: En las infecciones por enterobacterias productoras de β-lactamasas de espectro extendido (BLEE), los β-lactámicos preferidos para tratamiento son los carbapenémicos. Sin embargo, estudios clínicos muestran eficacia de piperacilina/tazobactam en ciertas infecciones por Escherichia coli productoras de BLEE. Objetivo: Determinar la cura clínica y microbiológica con piperacilina/tazobactam en pacientes con infecciones por E. coli productoras de BLEE, tipo CTX-M. Materiales/Métodos: Estudio descriptivo, retrospectivo, con adultos internados en un hospital universitario. Incluimos infecciones del tracto urinario (ITU), intra-abdominales (IIA) e infecciones de tejidos blandos (ITB). Resultados: Estudiamos 40 pacientes, donde 65% correspondían a ITU, 25% IIA y 10 % ITB. La cura clínica global se logró en 89,4%, con mejores resultados en las ITU (100%), seguidas de ITB (80%) e IIA (70%). El 85% de las cepas tenía concentraciones inhibitorias mínimas (CIM) ≤ 8 μg/mL y 70% con CIM ≤ 4 μg/mL. La tasa de fracaso fue mayor en las infecciones con inóculos altos intraabdominales. La BLEE del tipo CTX-M-15 se encontró en 62,5%. Conclusiones: Piperacilina/tazobactam logró cura clínica y microbiológica, en pacientes con infecciones por E. coli productoras de BLEE susceptibles, especialmente en ITU e IPB y en menor medida en IIA.

Background: Carbapenems are the preferred β-lactamics for treatment for infections caused by enterobacteria producing extended-spectrum β-lactamases (ESBL); however, clinical studies show effectiveness of piperacillin/tazobactam in certain infections by Escherichia coli ESBL producers. Aim: To determine the clinical and micro-biological cure with piperacillin/tazobactam in patients with infections caused by E. coli ESBL producers, CTXM type. Methods: Retrospective descriptive study with adults hospitalized in a university hospital. We included urinary tract infections (UTI), intra-abdominal infections (IAI), soft tissue infections (STI) and/or bacteremia. Results: We studied 40 patients, where 65% corresponded to UTI, 25% to IAI and 10% were STI. The overall clinical cure was achieved in 89.4%, with the best results in the ITU (100%), followed by STI (80%) and 70% in IAI. The 85% of the strains had minimum inhibitory concentrations (MIC) ≤8 μg/ml and 70% with MIC ≤4 μg/mL, however the rate of failure were high in intra-abdominal infections with high inocula or not controlled; CTX-M-15 was found in the 62.5%. Conclusions: Piperacillin/tazobactam was efficient to obtain clinical and microbiological cure in patients with infections caused by ESBL producers but susceptible E. coli, especially in UTI and STI and to a lesser extent in IAI.

Failure of Ciprofloxacin Therapy in the Treatment of Community-Acquired Acute Pyelonephritis caused by In-Vitro Susceptible Escherichia coli Strain Producing CTX-Type Extended-Spectrum β-Lactamase

While carbapenems are the drug of choice to treat extended-spectrum-β-lactamase (ESBL)-producing strains, some alternative carbapenem-sparing regimens are suggested for antibiotic stewardship. We experienced a case of ciprofloxacin treatment failure for acute pyelonephritis caused by an apparently susceptible Escherichia coli. A 71-year-old woman presented the emergency department with fever for 7 days and bilateral flank pain for 2 days. The laboratory results and abdominopelvic computed tomography finding were compatible with acute pyelonephritis. During 3-day ciprofloxacin therapy, the patient remained febrile with persistent bacteremia. After the change in antibiotics to ertapenem, the patient’s clinical course started to improve. ESBL-producing E. coli isolates were identified in all three consecutive blood samples. Pulsed-field gel electrophoresis (PFGE) patterns, serotypes, and sequence types showed the three isolates were derived from the identical strain. The isolates produced CTX-M-14 type ESBL belonging to the ST69 clonal group. Despite in vitro susceptibility, the failure was attributed to a gyrA point mutation encoding Ser83Leu within quinolone resistance-determining regions. This case suggests that ciprofloxacin should be used cautiously in the treatment of serious infections caused by ciprofloxacin-susceptible, ESBL-producing E. coli, even in acute pyelonephritis because in-vitro susceptibility tests could fail to detect certain genetic mutations.

Failure of Ciprofloxacin Therapy in the Treatment of Community-Acquired Acute Pyelonephritis caused by In-Vitro Susceptible Escherichia coli Strain Producing CTX-Type Extended-Spectrum β-Lactamase

While carbapenems are the drug of choice to treat extended-spectrum-β-lactamase (ESBL)-producing strains, some alternative carbapenem-sparing regimens are suggested for antibiotic stewardship. We experienced a case of ciprofloxacin treatment failure for acute pyelonephritis caused by an apparently susceptible Escherichia coli. A 71-year-old woman presented the emergency department with fever for 7 days and bilateral flank pain for 2 days. The laboratory results and abdominopelvic computed tomography finding were compatible with acute pyelonephritis. During 3-day ciprofloxacin therapy, the patient remained febrile with persistent bacteremia. After the change in antibiotics to ertapenem, the patient’s clinical course started to improve. ESBL-producing E. coli isolates were identified in all three consecutive blood samples. Pulsed-field gel electrophoresis (PFGE) patterns, serotypes, and sequence types showed the three isolates were derived from the identical strain. The isolates produced CTX-M-14 type ESBL belonging to the ST69 clonal group. Despite in vitro susceptibility, the failure was attributed to a gyrA point mutation encoding Ser83Leu within quinolone resistance-determining regions. This case suggests that ciprofloxacin should be used cautiously in the treatment of serious infections caused by ciprofloxacin-susceptible, ESBL-producing E. coli, even in acute pyelonephritis because in-vitro susceptibility tests could fail to detect certain genetic mutations.

Establishment and evaluation of a rabbit model of premature ovarian failure induced by cyclophosphamide / 中国比较医学杂志

Objective To compare different regimens of intraperitoneal injection of cyclophosphamide (CTX) to establish a rabbit model of premature ovarian failure (POF), and provide a useful experimental tool for further research of premature ovarian failure. Methods A total of twenty-one 5-6 months old rabbits were randomly divided into 4 groups. The group A (normal control group) included 3 rabbits without any treatment. The group B (the first model group) included 6 rabbits, received a single intraperitoneal injection of 50 mg/kg cyclophosphamide. Six rabbits in the group C (the second model group) were injected with 50 mg/kg cyclophosphamide once daily for 2 days. The group D (the third model group, also n=6) was injected with 50 mg/kg cyclophosphamide on the first day and then followed by 8 mg/ (kg·d) injection q.d. in the 14 consecutive days. Body weight and ovary weight of the rabbits in each group were measured, and the changes of body weight and the ovary index were analyzed. Morphological changes of the ovarian follicles were observed by HE staining and the numbers of normal and abnormal follicles at different developmental stages were counted and analyzed. Cell apoptosis was analyzed by TUNEL staining and changes in the serum levels of estradiol (E2) were detected by ELISA. Results The body weight of rabbits in both groups B and group C was not significantly changed during the experimental period (P＞ 0. 05). Rabbits in the group D showed a slight growth (P ＜ 0. 05) and high mortality. The ovary index in group C was significantly lower than that in the group A (P ＜ 0. 05). The ratios of abnormal primordial and primary follicles in groups B and C were significantly increased (P ＜ 0. 017), and the ratio of abnormal primordial follicles in the group C was increased more significantly (P ＜ 0. 017). However, there was no significant difference in the ratios of abnormal primary follicles between groups B and C (P＞ 0. 017). Among the groups A, B and C, there was no significant difference in the ratios of abnormal secondary and antral follicles (P＞ 0. 05). Apoptosis mainly occurred in granulosa cells of the ovarian follicles. The apoptosis rate of groups B and C was significantly higher than that in the group A (P ＜ 0. 05), and the apoptosis rate of group C was higher than that in the group B (P ＜ 0. 05). In the group B, the serum E2 level reached the peak value on the 7th day, significantly higher than that on the 35th day (P ＜ 0. 05), and then the level was decreased gradually. In the group C, the E2 level was continuously decreased and the level on the last day before drug injection was significantly higher than that at the 35th day (P ＜ 0. 05). Conclusions Intraperitoneal injection of 50 mg/kg cyclophosphamide once daily for 2 days is a most suitable method for the establishment of rabbit model of premature ovarian failure (POF).

The distribution of CTX-M drug resistance genotypes in Escherichia coli isolated from urethra in children and the influence of pH changes on its drug resistance / 临床儿科杂志

Objectives To explore the distribution of CTX-M drug resistance genotypes in Escherichia coli isolated from urethra in children and the influence of pH changes on its drug resistance. Methods A total of 113 strains of Escherichia coli isolated from clean midstream urine in children with urinary tract infection were cultured from October 2013 to May 2014. The drug sensitivity of ESBL-producing Escherichia coli was detected and counted. The distribution of CTX-M drug resistance genotypes were analyzed by PCR and gene sequencing. Different pH environment was established in vitro to evaluate the effect of pH on drug resistance of CTX-M resistant Escherichia coli. Results In 113 Escherichia coli strains, there were 68 ESBL-producing strains (60.18％), in which rate of drug resistance to meropenem and imipenem were 1.47％ and 2.94％ respectively. There were 41 strains carried CTX-M drug resistance genotype, which mainly were type CTX-M-14 and type CTX-M-15, 18 strains each. Compared with neutral environment of the pH value at 6 or 6.5, the rate of Escherichia coli resistant to cefuroxime, cefotaxime, ceftazidime and ceftriaxone had no difference (P>0.05), while the resistance to cefepime was significantly increased when pH was 6.0 (P<0.01). With the pH value at 8 or 8.5, the rate of Escherichia coli resistance to ceftazidime and cefepime was significantly decreased, and with the pH value at 8.5 the rate of Escherichia coli resistance to cefotaxime also significantly decreased (P<0.01). Conclusions The rate of ESBL-producing Escherichia coli resistance to carbapenem antibiotic is low. The rate of Escherichia coli carrying CTX-M drug resistance genotype is high with CTX-M-14 and CTX-M-15 being the most prevalent genotypes. Properly alkalization of urine may contribute to the treatment of CTX-M resistant Escherichia coli in children with urinary tract infection.

Prevalence of Fecal Carriage of CTX-M-15 Beta-Lactamase-Producing Escherichia coli in Healthy Children from a Rural Andean Village in Venezuela

OBJECTIVES: Antimicrobial resistant extended-spectrum-β-lactamase-producing Enterobacteriaceae (ESBL-PE) have been shown to be present in healthy communities. This study examined healthy children from the rural Andean village of Llano del Hato, Mérida, Venezuela, who have had little or no antibiotic exposure to determine the prevalence of fecal carriage of ESBL-producing Escherichia coli (ESBL-EC). METHODS: A total of 78 fecal samples were collected in healthy children aged from 1 to 5 years. ESBL-EC were selected in MacConkey agar plates with cefotaxime and further confirmed by the VITEK 2 system. ESBL were phenotypically detected and presence of bla genes and their variants were confirmed by molecular assays. Determination of phylogenetic groups was performed by PCR amplification. Risk factors associated with fecal carriage of ESBL-EC-positive isolates were analyzed using standard statistical methods. RESULTS: Of the 78 children studied, 27 (34.6%) carried ESBL-EC. All strains harbored the bla(CTX-M-15) allele. Of these, 8 were co-producers of bla(TEM-1), bla(TEM-5), bla(SHV-5) or bla(SHV-12). Co-resistance to aminoglycosides and/or fluoroquinolones was observed in 9 strains. 51.9% of ESBL-EC isolates were classified within phylogroup A. A significant, positive correlation was found between age (≥2.5 – ≤5 years), food consumption patterns and ESBL-EC fecal carriage. CONCLUSION: This is the first study describing the high prevalence of fecal carriage of ESBL-EC expressing CTX-M-15- among very young, healthy children from a rural Andean village in Venezuela with scarce antibiotic exposure, underlining the importance of this population as a reservoir.