Infected tracheal diverticulum: a rare association with alpha-1 antitrypsin deficiency / Divertículo da traqueia infectado: um caso de associação rara com deficiência de alfa-1 antitripsina

Tracheal diverticulum, defined as a benign outpouching of the tracheal wall, is rarely diagnosed in clinical practice. It can be congenital or acquired in origin, and most cases are asymptomatic, typically being diagnosed postmortem. We report a case of a 69-year-old woman who was hospitalized after presenting with fever, fatigue, pleuritic chest pain, and a right neck mass complicated by dysphagia. Her medical history was significant: pulmonary emphysema (alpha-1 antitrypsin deficiency); bronchiectasis; and thyroidectomy. On physical examination, she presented diminished breath sounds and muffled heart sounds, with a systolic murmur. Laboratory tests revealed elevated inflammatory markers, a CT scan showed an air-filled, multilocular mass in the right tracheal wall, and magnetic resonance imaging confirmed the CT findings. Fiberoptic bronchoscopy failed to reveal any abnormalities. Nevertheless, the patient was diagnosed with tracheal diverticulum. The treatment approach was conservative, consisting mainly of antibiotics. After showing clinical improvement, the patient was discharged.

Divertículos da traqueia são evaginações benignas da parede traqueal e raramente diagnosticados na prática clínica. Podem ser congênitos ou adquiridos, e na maioria dos casos são assintomáticos, sendo tipicamente diagnosticados em estudos post-mortem. Relatamos o caso de uma mulher de 69 anos que foi hospitalizada após apresentar febre, fadiga, dor torácica pleurítica e uma massa cervical à direita complicada por disfagia. Tinha antecedentes pessoais de enfisema pulmonar (deficiência de alfa-1 antitripsina), bronquiectasias e tireoidectomia. Ao exame físico apresentava murmúrio vesicular diminuído, hipofonese cardíaca e um sopro sistólico. Laboratorialmente apresentava marcadores inflamatórios elevados, e uma TC mostrou uma massa aérea, multiloculada na parede direita da traqueia, achados confirmados por ressonância magnética nuclear. Realizou ainda uma fibrobroncoscopia que se revelou normal. Assumiu-se o diagnóstico de divertículo da traqueia. O tratamento proposto foi conservador, consistindo principalmente de antibioticoterapia. Após melhora clínica, a paciente recebeu alta.

Severe autogenously fecal peritonitis in ageing Wistar rats. Response to intravenous meropenem

PURPOSE: To evaluate the treatment outcome of severe peritonitis in rats with increasing age. METHODS: Thirty Wistar rats stratified in three groups: group I - six month-old; group II - 12 month-old; and group III - 18 month-old, underwent autogenously fecal peritonitis (6 ml/kg rat), and were treated with intravenous meropenem. The survival animals were followed-up for 45 days. The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee. RESULTS: There was a significant increase in the mortality and morbidity in elderly rats. Of interest, even among young survival rats presenting with severe residual abscesses both in the abdomen and thorax cavities, they present an almost normal life. CONCLUSIONS: The treatment of severe autogenously fecal peritonitis with intravenous meropenem reached reasonable results in rats with six and twelve months of age, even considering residual abscesses on abdomen and thorax cavities. However, the great majority (80%) of elderly rats could not overcome the initial severe infectious challenge, proving that ageing is a very important risk factor for impairing immune response. Thus, sepsis remains a challenging situation, especially in elderly. .

Pharmacodynamic profiling of commonly prescribed antimicrobial drugs against Escherichia coli isolates from urinary tract

Since antimicrobial resistance among uropathogens against current first line agents has affected the management of severe urinary tract infection, we determined the likelihood that antibiotic regimens achieve bactericidal pharmacodynamic exposures using Monte Carlo simulation for five antimicrobials (ciprofloxacin, ceftriaxone, piperacillin/tazobactam, ertapenem, and meropenem) commonly prescribed as initial empirical treatment of inpatients with severe community acquired urinary tract infections. Minimum inhibitory concentration determination by Etest was performed for 205 Brazilian community urinary tract infection Escherichia coli strains from 2008 to 2012 and 74 E. coli bloodstream strains recovered from a surveillance study. Pharmacodynamic exposure was modeled via a 5000 subject Monte Carlo simulation. All isolates were susceptible to ertapenem and meropenem. Piperacillin/tazobactam, ceftriaxone and ciprofloxacin showed 100%, 97.5% and 83.3% susceptibility among outpatient isolates and 98.6%, 75.7% and 64.3% among inpatient isolates, respectively. Against outpatient isolates, all drugs except ciprofloxacin (82.7% in aggressive and 77.6% in conservative scenarios) achieved high cumulative fraction of response: car-bapenems and piperacillin/tazobactam cumulative fraction of responses were close to 100%, and ceftriaxone cumulative fraction of response was 97.5%. Similar results were observed against inpatients isolates for carbapenems (100%) and piperacillin/tazobactam (98.4%), whereas ceftriaxone achieved only 76.9% bactericidal cumulative fraction of response and ciprofloxacin 61.9% (aggressive scenario) and 56.7% (conservative scenario) respectively. Based on this model, standard doses of beta-lactams were predicted to deliver sufficient pharmacodynamic exposure for outpatients. However, ceftriaxone should be avoided for inpatients and ciprofloxacin empirical prescription should be avoided in both inpatients and outpatients with complicated urinary tract infection.

Detection and characterization of metallo-β-lactamases in Pseudomonas aeruginosa by phenotypic and molecular methods from clinical samples in a tertiary care hospital / Detección y caracterización de la metallo-betalactamasa en la Pseudomonas aeruginosa mediante métodos fenotípicos y moleculares a partir de muestras clínicas en un hospital de atención terciaria

AIMS: The aim of this study was to detect and characterize the presence of metallo-β-lactamase (MBL) production in multidrug resistant (MDR) P aeruginosa collected from clinical samples in a tertiary care hospital. METHODS AND MATERIALS: A total of 67 non-repetitive isolates of MDR P aeruginosa recovered from various clinical specimens were screened for MBL production by IPM/MEM-EDTA combined disc test. Polymerase chain reaction was performed on all isolates using blaIMP and blaVIM consensus primers to characterize them genotypically. RESULTS: Among 67 P aeruginosa isolates, 62.7% (42/67) and 70.1% (47/67) were resistant to imipenem and meropenem respectively and 47 (70.1%) were found to be MBL producers. Among this 47 MBL-producing isolates, 41 (61.1%) strains carried the blaVIM gene and 2 (3%) strains carried the blaIMP gene. Three strains were phenotypically negative but positive genotypically for blaVIM gene. One strain was resistant to both imipenem and meropenem but did not show phenotypic positivity. CONCLUSION: This study confirms the dissemination of blaVIM genes among MDR Pseudomonas aeruginosa and hence it is indispensible to identify and aptly control the threat of horizontal and vertical transfer.

OBJETIVO: El objetivo de este estudio es descubrir y caracterizar la presencia de producción de metallo-betalactamasa (MBL) en P aeruginosa resistente a los multifármacos (RMF), recogida de muestras clínicas de un hospital de atención terciaria. MÉTODO: Un total de 67 aislados no repetitivos de P aeruginosa RMF obtenidos de varios specímenes clínicos, fueron tamizados en busca de producción de MBL, mediante una prueba de disco combinado IPM/MEM-EDTA. Se efectuó una reacción en cadena de la polimerasa sobre todos los aislados, usando iniciadores de consenso blaIMP y blaVIM para la caracterización genotípica. RESULTADOS: Entre los aislados de P aeruginosa, 62.7% (42/67) y 70.1% (47/67) fueron resistentes al Imipenem y al Meropenem respectivamente, mientras que se halló que 47 (70.1%) eran productores de MBL. De los 47 aislados productores de MBL, 41 (61.1%) cepas eran portadoras del gen blaVIM en tanto que 2 (3%) cepas eran portadoras del gen blaIMP. Tres cepas fueron fenotípicamente negativas, pero genotípicamente positivas con respecto al gen blaVIM. Una cepa fue resistente tanto al Imipenem como al Meropenem, pero no mostró positividad fenotípicamente. CONCLUSIÓN: El presente estudio confirma la diseminación de los genes blaVIM entre las Pseudomonas aeruginosa RMF. Es importante identificar así como controlar adecuadamente la amenaza de la transferencia horizontal y vertical.

Metallo-β-lactamase-production in meropenem-susceptible Pseudomonas aeruginosa isolates: risk for silent spread

The aim of this study was to characterize two metallo-β-lactamases (MBLs)-producing Pseudomonas aeruginosa clinical isolates showing meropenem susceptibility. Antimicrobial susceptibility was assessed by automated testing and Clinical and Laboratory Standards Institute agar dilution method. MBL production was investigated by phenotypic tests. Molecular typing was determined by pulsed field gel electrophoresis (PFGE). MBL-encoding genes, as well as their genetic context, were identified by polymerase chain reaction (PCR) and sequencing. The location of blaIMP-16 was determined by plasmid electrophoresis, Southern blot and hybridization. Transcriptional levels of blaIMP-16, mexB, mexD, mexF, mexY, ampC and oprD were determined by semi-quantitative real time PCR. The P. aeruginosa isolates studied, Pa30 and Pa43, showed imipenem and meropenem susceptibility by automated testing. Agar dilution assays confirmed meropenem susceptibility whereas both isolates showed low level of imipenem resistance. Pa30 and Pa43 were phenotypically detected as MBL producers. PFGE revealed their clonal relatedness. blaIMP-16 was identified in both isolates, carried as a single cassette in a class 1 integron that was embedded in a plasmid of about 60-Kb. Pa30 and Pa43 overexpressed MexAB-OprM, MexCD-OprJ and MexXY-OprM efflux systems and showed basal transcriptional levels of ampC and oprD. MBL-producing P. aeruginosa that are not resistant to meropenem may represent a risk for therapeutic failure and act as silent reservoirs of MBL-encoding genes.

Interacción entre meropenem y ácido valproico: A propósito de dos casos pediátricos / Pharmacological interaction between meropenem and valproic acid: a report of two cases

The pharmacological interaction between meropenem and valproic acid is potentially serious, especially in critically ill patients, resulting in low plasmatic levels of the anticonvulsant. However, to our knowledge, this interaction between meropenem and reduced valproic acid plasma levels has not been reported in the pediatric chilean population. We present two clinical cases of chilean children, thus reporting that this interaction is present in our population, with an aim at educating physicians about the possibility of such interaction.

La interacción farmacológica entre meropenem y ácido valproico en pacientes críticos es potencialmente grave, reflejándose en una disminución del fármaco anticonvulsivante mayor a 70%. Se desconocen estrategias efectivas que la reviertan. Esta interacción no ha sido descrita en pacientes chilenos pediátricos. A través de la presentación de dos casos clínicos alertamos que la interacción puede suceder en nuestra población y educamos a los pediatras que indican meropenem sobre la posibilidad de este evento.

Resistencia a carbapenemes en aislamientos de pseudomonas aeruginosa: un ejemplo de interacción entre distintos mecanismos / Carbapenem resistance in pseudomonas aeruginosa isolates: an example of interaction between different mechanisms

Objetivo. Identificar la proteína de membrana externa ausente en los aislamientos resistentes y determinar tanto las causas de su ausencia en la membrana, como la presencia de otros mecanismos de resistencia a carbapenemes en aislamientos clínicos de Pseudomonas aeruginosa. Métodos. Se estudió un brote de 20 aislamientos de P. aeruginosa previamente caracterizados como productores de la metalobetalactamasa IMP-13. Estos aislamientos presentaron igual expresión de la enzima IMP-13, pero solo cinco de ellos fueron resistentes acarbapenemes. En esos cinco aislamientos resistentes se confirmó la ausencia de una proteína de membrana externa. Se secuenciaron oprD y ampC; se identificaron las proteínas de membrana externa por desorción/ionización láser asistida por matriz/espectometría de masa tiempo de vuelo (MALDI-TOF); se determinó el nivel de expresión de OprD, de AmpC y de los sistemas de eflujo tipo Mex, por reacción en cadena de polimerasa en tiempo real, y por último, se determinó la contribución del déficit de OprD a la resistencia a carbapenemes. Resultados. La proteína de la membrana externa ausente en el grupo R (resistentes a ambos carbapenemes) fue identificada como OprD-TS, pero no se observaron variaciones en suexpresión. El gen oprD presentó mutaciones en los cinco aislamientos resistentes. Se observó la misma producción de la enzima tipo AmpC PDC-5 y del sistema de eflujo Mex AB-OprM entre los aislamientos sensibles y resistentes a carbapenemes. Se analizó cómo la presencia conjunta de IMP-13 y el déficit de OprD contribuyen al aumento de la resistencia.Conclusiones. Distintos mecanismos contribuyen a la resistencia de aislamientos productores de IMP-13 a carbapenemes. La posibilidad de no detectar estos aislamientos productores de IMP-13 representa un riesgo latente de selección de mutantes con mecanismos de resistencia que se suman para aumentar la resistencia a carbapenemes.

Objective. To identify the outer membrane protein absent in the resistant isolates and to determine both the causes of its absence in the membrane and the presence of othermechanisms of carbapenem resistance in clinical isolates of Pseudomonas aeruginosa. Methods. Twenty isolates from an outbreak of P. aeruginosa previously characterized as metallo-beta-lactamase IMP-13 producers were studied. All the isolates exhibitedequal expression of the IMP-13 enzyme, but only five of them were carbapenemresistant. It was found that the five resistant isolates lacked a outer membrane protein. The oprD and ampC genes were sequenced; the outer membrane proteins were identifiedusing matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry; the OprD and AmpC expressions, as well as the Mex efflux system, were assessed by real-time polymerase chain reaction; and finally, the contribution of reduced OprD to carbapenem resistance was determined. Results. The absent outer membrane protein in group R was identified as OprD-TS; however, no variations in its expression were observed. The oprD gene presentedmutations in the five resistant isolates. The production of AmpC PDC-5-type enzyme and the MexAB-OprM efflux system was the same in both carbapenem-sensitive and‑resistant isolates. The contribution of the combined presence of IMP-13 and reducedOprD to increased resistance was examined. Conclusions. Different mechanisms contribute to carbapenem resistance in IMP-13-producing isolates. The possibility that these IMP-13-producing isolates could go undetected poses a latent risk when selecting mutants with added resistancemechanisms in order to enhance carbapenem resistance.

Antimicrobial activity of doripenem against Gram-negative pathogens: results from INVITA-A-DORI Brazilian study

In vitro activity of doripenem and comparator antimicrobial agents was evaluated against Gram-negative bacilli recently isolated from Brazilian private hospitals that were enrolled in the INVITA-A-DORI Brazilian Study. A total of 805 unique Gram-negative bacilli were collected from patients hospitalized at 18 medical centers between May/08 and March/09. Each hospital was asked to submit 50 single Gram-negative bacilli isolated from blood, lower respiratory tract or intraabdominal secretions. Bacterial identification was confirmed and antimicrobial susceptibility testing was performed using Clinical Laboratory Standards Institute (CLSI) microdilution method at a central laboratory. CLSI M100-S21 (2011) or US-FDA package insert criteria (tigecycline) was used for interpretation of the antimicrobial susceptibility results. Doripenem was as active as meropenem and more active than imipenem against E. coli and K. pneumoniae isolates. A total of 50.0 percent of Enterobacter spp. isolates were resistant to ceftazidime but 85.7 percent of them were inhibited at doripenem MICs < 1 µg/mL. Polymyxin B was the only agent to show potent activity against Acinetobacter spp. (MIC50/90, < 0.5/1 µg/mL) and P. aeruginosa (MIC50/90, 1/2 µg/mL). Although high rates of imipenem (53.1 percent) and meropenem (44.5 percent) resistance were detected among P. aeruginosa, doripenem showed MIC50 of 16 µg/mL against imipenem-resistant P. aeruginosa and inhibited a greater number of imipenem-resistant P. aeruginosa (10.5 percent) at MIC values of < 4 µg/mL than did meropenem (0.0 percent). In this study, doripenem showed similar in vitro activity to that of meropenem and retained some activity against imipenem-resistant P. aeruginosa isolated from Brazilian medical centers.

Assessing the pharmacodynamic profile of intravenous antibiotics against prevalent Gram-negative organisms collected in Colombia

OBJECTIVES: This study was designed to simulate standard and optimized dosing regimens for intravenous antibiotics against contemporary populations of Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa using MIC distribution data to determine which of the tested carbapenem regimens provided the greatest opportunity for obtaining maximal pharmacodynamic (PD) activity. METHODS: The isolates studied were obtained from the COMPACT-COLOMBIA surveillance program conducted between February and November 2009. Antimicrobial susceptibility testing was conducted by broth microdilution method according to the CLSI guidelines. Doripenem, imipenem-cilastatin, and meropenem, were the modeled antibiotics. A 5,000 patient Monte Carlo simulation was performed for each regimen and PD targets were defined as free drug concentrations above the MIC for at least 40 percent of the dosing interval. RESULTS: All carbapenem regimens obtained optimal exposures against E. coli, unlike the other Enterobacteriaceae tested. Against P. aeruginosa, only a prolonged infusion of doripenem exceeded the 90 percent cumulative fraction of response (CFR) threshold. Worrisomely, no regimens for any of the drugs tested obtained optimal CFR against A. baumannii. For P. aeruginosa intensive care unit (ICU) isolates, CFR was approximately 20 percent lower for isolates collected in the respiratory tract compared with bloodstream or intra-abdominal for imipenem and meropenem. Noteworthy, all doripenem and meropenem regimens achieved greater than 90 percent CFR against bloodstream and respiratory isolates of K. pneumoniae. CONCLUSIONS: Our data suggests that higher dosing and prolonged infusion of doripenem or meropenem may be suitable for empirically treating ICU P. aeruginosa, while none of the carbapenems achieved optimal cumulative fraction of response against A. baumannii. Standard dosing regimens of all the carbapenems tested achieved optimal CFR against E. coli isolates, but higher carbapenem dosages might be required for empiric treatment of K. pneumoniae, particularly from an intra-abdominal source. Non-standard dosage regimens studied in this modeling should be proven effective in prospective clinical trials.

Detection of SPM and IMP metallo-β-lactamases in clinical specimens of Pseudomonas aeruginosa from a Brazilian public tertiary hospital

Phenotypic and genotypic SPM and IMP metallo-β-lactamases (MBL) detection and also the determination of minimal inhibitory concentrations (MIC) to imipenem, meropenem and ceftazidime were evaluated in 47 multidrug-resistant Pseudomonas aeruginosa isolates from clinical specimens. Polymerase chain reaction detected 14 positive samples to either blaSPM or blaIMP genes, while the best phenotypic assay (ceftazidime substrate and mercaptopropionic acid inhibitor) detected 13 of these samples. Imipenem, meropenem and ceftazidime MICs were higher for MBL positive compared to MBL negative isolates. We describe here the SPM and IMP MBL findings in clinical specimens of P. aeruginosa from the University Hospital of Botucatu Medical School, São Paulo, Brazil, that reinforce local studies showing the high spreading of blaSPM and blaIMP genes among brazilian clinical isolates.

Carbapenem stewardship: positive impact on hospital ecology

INTRODUCTION: Excessive group 2 carbapenem use may result in decreased bacterial susceptibility. OBJECTIVE: We evaluated the impact of a carbapenem stewardship program, restricting imipenem and meropenem use. METHODS: Ertapenem was mandated for ESBL-producing Enterobacteriaceae infections in the absence of non-fermenting Gram-negative bacilli (GNB) from April 2006 to March 2008. Group 2 carbapenems were restricted for use against GNB infections susceptible only to carbapenems and suspected GNB infections in unstable patients. Cumulative susceptibility tests were done for nosocomial pathogens before and after restriction using Clinical and Laboratory Standards Institute (CLSI) guide-lines.Vitek System or conventional identification methods were performed and susceptibility testing done by disk diffusion according to CLSI.Antibiotic consumption (t-test) and susceptibilities (McNemar's test) were determined. RESULTS: The defined daily doses (DDD) of group 2 carbapenems declined from 61.1 to 48.7 DDD/1,000 patient-days two years after ertapenem introduction (p = 0.027). Mean ertapenem consumption after restriction was 31.5 DDD/1,000 patient-days. Following ertapenem introduction no significant susceptibility changes were noticed among Gram-positive cocci. The most prevalent GNB were P. aeruginosa, Klebsiella pneumoniae, and Acinetobacter spp. There was no change in P. aeruginosa susceptibility to carbapenems. Significantly improved P. aeruginosa and K. pneumoniae ciprofloxacin susceptibilities were observed, perhaps due to decreased group 2 carbapenem use. K. pneumoniae susceptibility to trimethoprim-sulfamethoxazole improved. CONCLUSION: Preferential use of ertapenem resulted in reduced group 2 carbapenem use, with a positive impact on P. aeruginosa and K. pneumoniae susceptibility.

Prevalence of carbapenem resistant Pseudomonas aeruginosa and Acinetobacter baumannii in high complexity hospital

Pseudomonas aeruginosa and Acinetobacter baumannii are Gram-negative bacilli that in the last decades have become prevalent agents of hospital infection due to high antimicrobial resistance developed by these microorganisms. The present study is a retrospective analysis of all positive cultures for these microorganisms in the period of January 2004 to December 2008. Resistance levels of A. baumannii and P. aeruginosa to carbapenems was high and showed a trend to increase during the period of study. In recent years the increasing incidence and resistance levels of A. baumannii and P. aeruginosa to the antimicrobials used for their treatment in the hospital setting underscores the relevance of infections caused by these bacteria. The selective pressure caused by indiscriminated use of broad-spectrum antibiotics in empirical hospital infections is probably the main reason for such an increase with the consequent impact upon patient morbidity and mortality.

Indications of carbapenem resistance evolution through heteroresistance as an intermediate stage in Acinetobacter baumannii after carbapenem administration / Indicações da evolução da resistência ao carbapenem através da heteroresistência como estágio intermediário no Acinetobacter baumannii após administração de carbapenem

We describe an in vivo evolution of an antimicrobial profile from susceptibility to full-resistance to carbapenems, with heteroresistance as an intermediate stage, in an Acinetobacter baumannii strain. Heteroresistance was characterized by the growth of sub-populations within the susceptibility halo in both disk-diffusion and Etest. PCRs for the main A. baumannii carbapenemases were negative. The exact resistance mechanism, diagnostic methods and clinical relevance of heteroresistance in A. baumannii warrant further investigations. This is the first description of such phenomenon in vivo and the second report of heteroresistance to carbapenems in A. baumannii.

Descrevemos a evolução in vivo, de um perfil de sensibilidade aos antimicrobianos, passando de sensibilidade a resistência total aos antibióticos carbapenêmicos, com um estágio intermediário de heteroresistência em isolado de Acinetobacter baumannii. A heteroresistência foi caracterizada pelo crescimento de sub-população na zona de inibição pelo método de disco-difusão e pelo Etest. PCRs para as principais carbapenemases envolvidas com resistência neste microrganismo foram negativas. O exato mecanismo de resistência envolvido, método diagnóstico e relevância clínica justificam investigação adicional. Esta é a primeira descrição deste fenômeno in vivo e o segundo relato de heteroresistência em A. baumannii.

Cerebral abscess caused by Serratia marcescens in a premature neonate

BACKGROUND: Cerebral abscesses are extremely rare in neonates. Serratia marcescens is an unusual cause of sepsis and neurological spread is especially ominous. PURPOSE: To report the case of a 34-week neonate who developed this rare condition and to discuss diagnostic and therapeutic measures. CASE REPRT: A 34-week male neonate sequentially developed respiratory distress syndrome, early sepsis and necrotizing enterocolitis; later cultures revealed S. marcescens. After deterioration, a cerebral abscess became evident, which revealed S. marcescens. Clinical improvement ensued after high-dose amikacin and meropenem. CONCLUSION: Clinical signs are often non-specific. Proper diagnostic measures, neurosurgical consultation and aggressive antibiotic therapy are essential for these high-risk neonates.

INTRODUÇÃO: Abscessos cerebrais são extremamente raros em neonatos. Serratia marcescens é causadora incomum de sepse nestes pacientes e a disseminação no sistema nervoso central é grave. OBJETIVO: Relatar um prematuro de 34 semanas que desenvolveu esta condição e discutir as medidas diagnósticas e terapêuticas. RELATO DE CASO: Prematuro masculino de 34 semanas desenvolveu síndrome do desconforto respiratório, sepse neonatal e enterocolite necrotizante; hemoculturas revelaram S. marcescens. Após deterioração clínica, evidenciou-se um abscesso cerebral cuja drenagem revelou S. marcescens. Houve melhora após introdução de amicacina e meropenem. CONCLUSÃO: Os sinais clínicos são inespecíficos. Passos diagnósticos apropriados, avaliação neurocirúrgica precoce e antibioticoterapia agressiva são essenciais para estes prematuros.

Avaliação da atividade in vitro do meropenem contra cepas de Klebsiella pneumoniae produtoras de betalactamases de espectro expandido isoladas na cidade de Fortaleza, Ceará / Evaluation of the in vitro activity of meropenem against strains of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae isolated in the city of Fortaleza, Ceará

Betalactamases de espectro estendido são mediadas por plasmídios. Essas enzimas possuem a habilidade de hidrolizar antibióticos beta-lactâmicos. Nesse estudo, avaliamos a atividade in vitro do meropenem contra cepas de Klebsiella pneumoniae produtoras de ESBLs. Foram estudadas 14 cepas. A susceptibilidade dessas cepas para o meropenem foi de 100 por cento.

Extended-spectrum beta-lactamases are plasmid-mediated. These enzymes have the ability to hydrolyze beta-lactam antibiotics. In this study, we evaluated the in vitro activity of meropenem against ESBL-producing Klebsiella pneumoniae strains. Fourteen strains were studied. The susceptibility of these strains to meropenem was 100 percent.

Cefepime restriction improves gram-negative overall resistance patterns in neonatal intensive care unit

Antibiotic restriction can be useful in maintaining bacterial susceptibility. The objective of this study was verify if restriction of cefepime, the most frequently used cephalosporin in our neonatal intensive care unit (NICU), would ameliorate broad-spectrum susceptibility of Gram-negative isolates. Nine hundred and ninety-five premature and term newborns were divided into 3 cohorts, according to the prevalence of cefepime use in the unit: Group 1 (n=396) comprised patients admitted from January 2002 to December 2003, period in which cefepime was the most used broad-spectrum antibiotic. Patients in Group 2 (n=349) were admitted when piperacillin/tazobactam replaced cefepime (January to December 2004) and in Group 3 (n=250) when cefepime was reintroduced (January to September 2005). Meropenem was the alternative third-line antibiotic for all groups. Multiresistance was defined as resistance to 2 or more unrelated antibiotics, including necessarily a third or fourth generation cephalosporin, piperacillin/tazobactam or meropenem. Statistics involved Kruskal-Wallis, Mann-Whitney and logrank tests, Kaplan-Meier analysis. Groups were comparable in length of stay, time of mechanical ventilation, gestational age and birth weight. Ninety-eight Gram-negative isolates were analyzed. Patients were more likely to remain free of multiresistant isolates by Kaplan-Meier analysis in Group 2 when compared to Group 1 (p=0.017) and Group 3 (p=0.003). There was also a significant difference in meropenem resistance rates. Cefepime has a greater propensity to select multiresistant Gram-negative pathogens than piperacillin/tazobactam and should not be used extensively in neonatal intensive care.