Editorial on the Research Topic of the Special Issue "Current Status of Acinetobacter Infections".

Emerging bacterial infections will continue to be an important issue for public health, mostly because of the constant changes on our earth [...].

The Burden of Carbapenem-Resistant Acinetobacter baumannii in ICU COVID-19 Patients: A Regional Experience.

Since the beginning of the COVID-19 pandemic, the impact of superinfections in intensive care units (ICUs) has progressively increased, especially carbapenem-resistant Acinetobacter baumannii (CR-Ab). This observational, multicenter, retrospective study was designed to investigate the characteristics of COVID-19 ICU patients developing CR-Ab colonization/infection during an ICU stay and evaluate mortality risk factors in a regional ICU network. A total of 913 COVID-19 patients were admitted to the participating ICUs; 19% became positive for CR-Ab, either colonization or infection (n = 176). The ICU mortality rate in CR-Ab patients was 64.7%. On average, patients developed colonization or infection within 10 ± 8.4 days from ICU admission. Scores of SAPS II and SOFA were significantly higher in the deceased patients (43.8 ± 13.5, p = 0.006 and 9.5 ± 3.6, p < 0.001, respectively). The mortality rate was significantly higher in patients with extracorporeal membrane oxygenation (12; 7%, p = 0.03), septic shock (61; 35%, p < 0.001), and in elders (66 ± 10, p < 0.001). Among the 176 patients, 129 (73%) had invasive infection with CR-Ab: 105 (60.7%) Ventilator-Associated Pneumonia (VAP), and 46 (26.6%) Bloodstream Infections (BSIs). In 22 cases (6.5%), VAP was associated with concomitant BSI. Colonization was reported in 165 patients (93.7%). Mortality was significantly higher in patients with VAP (p = 0.009). Colonized patients who did not develop invasive infections had a higher survival rate (p < 0.001). Being colonized by CR-Ab was associated with a higher risk of developing invasive infections (p < 0.001). In a multivariate analysis, risk factors significantly associated with mortality were age (OR = 1.070; 95% CI (1.028−1.115) p = 0.001) and CR-Ab colonization (OR = 5.463 IC95% 1.572−18.988, p = 0.008). Constant infection-control measures are necessary to stop the spread of A. baumannii in the hospital environment, especially at this time of the SARS-CoV-2 pandemic, with active surveillance cultures and the efficient performance of a multidisciplinary team.

Carbapenem-resistant Acinetobacter baumannii: Colonization, Infection and Current Treatment Options.

Carbapenem-resistant Acinetobacter baumannii (CRAB) causes colonization and infection predominantly in hospitalized patients. Distinction between the two is a challenge. When CRAB is isolated from a non-sterile site (soft tissue, respiratory samples, etc.), it probably represents colonization unless clear signs of infection (fever, elevated white blood count, elevated inflammatory markers and abnormal imaging) are present. Treatment is warranted only for true infections. In normally sterile sites (blood, cerebrospinal fluid) the presence of indwelling medical devices (catheters, stents) should be considered when evaluating positive cultures. In the absence of such devices, the isolate represents an infection and should be treated. If an indwelling device is present and there are no signs of active infection, the device should be replaced if possible, and no treatment is required. If there are signs of an active infection the device should be removed or replaced, and treatment should be administered. Current treatments options and clinical data are limited. No agent or combination regimen has been shown to be superior to any other in randomized clinical trials. Ampicillin-sulbactam appears to have the best evidence for initial use. This is probably due to its ability to saturate penicillin-binding proteins 1 and 3 when given in high dose. Tigecycline when used should be given in high dose as well. Polymyxins are a treatment option but are difficult to dose correctly and have significant side effects. Newer treatment options such as eravacycline and cefiderocol have potential; however, currently there are not enough data to support their use as single agents. Combination therapy appears to be the best treatment option and should always include high-dose ampicillin-sulbactam combined with another active agent such as high-dose tigecycline, polymyxins, etc. These infections require a high complexity of skill, and an infectious disease specialist should be involved in the management of these patients.

Vigilancia epidemiológica de Acinetobacter baumannii multirresistente a nivel hospitalario / Epidemiological surveillance of multidrug-resistant Acinetobacter baumannii at hospital level / Vigilância epidemiológica do Acinetobacter baumannii multirresistente em nível hospitalar

La Acinetobacter baumannii se considera como un agente microbiano de gran importancia clínica debido a la resistencia que ha adquirido a los antimicrobianos, esto trae como consecuencias complicaciones al referir una terapia antibiótica, prolongando la estancia en la hospitalización de los pacientes infectados con esta bacteria, causando un alto grado de mortalidad por su elevada capacidad de proliferación en las diferentes áreas hospitalarias. OBJETIVO. Describir la epidemiología de los brotes causados por Acinetobacter baumannii en Latinoamérica, así como también los mecanismos de Resistencia de este patógeno causando inconvenientes al momento de emplear los diferentes tratamientos terapéuticos. MATERIAL Y METODOS. Es una revisión sistemática bajo la declaración PRISMA de las investigaciones relacionadas al tema. Para la búsqueda de información se emplearon fuentes de datos provenientes de: Scielo, Redalyc, Google académico, se encontraron 43 artículos de los cuales solo 25 fueron válidos para la investigación. RESULTADOS. La resistencia que presenta la Acinetobacter baumannii a los antibióticos se incrementó con el pasar de los años. Este incremento de la resistencia se debe a diversos factores entre los cuales se destacan el desarrollo de ß-lactamasas dirigidas contra los betalactámicos, ya sea de amplio espectro o carbapenemasas; variaciones en las proteínas que forman parte de la membrana externa bacteriana, en las bombas de expulsión, perdida de porinas, modificaciones del lugar (blanco o diana) de acción de los antibióticos y variaciones en la expresión de proteínas fijadoras de penicilina. Esta variabilidad depende en parte de la capacidad de la bacteria para adquirir genes de resistencia, a menudo a través de una transferencia horizontal de genes CONCLUSIONES. La Acinetobacter baumannii se caracteriza por tener múltiples mecanismos de resistencia a antibióticos, lo que ha aumentado las consecuencias nocivas de este potencial patógeno y representa un desafío importante para los pacientes y el personal de salud.

Acinetobacter baumannii is considered as a bacterium of great clinical importance due to the resistance it has acquired to antimicrobials, which has triggered complications when referring an antibiotic therapy, prolonging the stay in the hospital of patients infected with this bacterium, causing a high degree of mortality due to its high proliferation capacity between different hospital areas. OBJETIVE. To describe the most relevant aspects about the epidemiology of the outbreaks caused by Acinetobacter baumannii in Latin America, as well as the different resistance mechanisms that this pathogen has acquired thus causing inconveniences when using the different therapeutic treatments. MATERIALS AND METHODS. A systematic review was carried out, under the PRISMA declaration, for the search of the information were used databases such as: Scielo, Redalyc, Google academic, 43 articles were found of which only 25 were valid for research. RESULTS. The resistance of Acitetobacter baumannii to different antibiotic groups has increased over the years. This increase in resistance is due to several factors among which stand out: ß-lactamases directed against beta-lactams, either broad spectrum or carbapenemases; variations in proteins of the outer membrane, ejection pumps, loss of porins, modifications of the place (target) of action of the antibiotics and alterations in the expression of penicillin-fixing proteins. This ability depends in part on the ability of this bacterium to acquire resistance genes, often through horizontal gene transfer. CONCLUSIONS. A. baumannii has developed multiple antibiotic resistance mechanisms, which increase the harmful consequences of this potential pathogen and represents a major challenge for patients and health personnel.

Acinetobacter baumannii é considerada como uma bactéria de grande importância clínica devido à resistência que adquiriu aos antimicrobianos, o que desencadeou complicações no momento de referir uma terapia antibiótica, prolongando a estadia na hospitalização dos pacientes infectados com esta bactéria, causando um elevado grau de mortalidade devido à sua elevada capacidade de proliferação entre diferentes áreas hospitalares. OBJECTIVO. Descrever os aspectos mais relevantes sobre a epidemiologia dos surtos causados por Acinetobacter baumannii a nível da América Latina, bem como os diferentes mecanismos de resistência que adquiriu este patógeno causando com isto inconvenientes o momento de empregar os diferentes tratamentos terapéuticos. MATERIAL E METODOS. Realizou-se uma revisão sistemática, sob a declaração PRISMA, para a busca da informação empregaram-se bases de dados como: Scielo, Redalyc, Google acadêmico, foram encontrados 43 artigos dos quais apenas 25 foram válidos para a pesquisa. RESULTADOS. A resistência que apresenta Acitetobacter baumannii aos diferentes grupos de antibioticos aumentou com o passar dos anos. Este aumento da resistência deve-se a diversos factores, entre os quais se destacam: ß-lactamases dirigidos contra os beta-lactâmicos, quer de largo espectro quer carbapenemases; variações nas proteínas da membrana externa, as bombas de expulsão, perda de porinas, modificações do local (branco) de acção dos antibioticos e alterações na expressão das proteínas fixadoras de penicilina. Esta capacidade depende em parte da capacidade desta bactéria para adquirir genes de resistência, muitas vezes através da transferência horizontal de genes. CONCLUSOES. Acinetobacter baumannii desenvolveu múltiplos mecanismos de resistência aos antibióticos, o que aumentou as consequências nocivas deste potencial patogênico e representa um desafio importante para os pacientes e o pessoal de saúde.

What is the optimal antibiotic treatment strategy for carbapenem-resistant Acinetobacter baumannii (CRAB)? A multicentre study in Korea.

OBJECTIVES: The optimal treatment option for carbapenem-resistant Acinetobacter baumannii (CRAB) is still limited. This study investigated the efficacy of three or more antibiotic types and regimens for treatment of CRAB infection in high CRAB endemic areas. METHODS: A multicentre retrospective study was conducted to evaluate the efficacy of treatment types and regimens of CRAB infections in 10 tertiary hospitals in the Republic of Korea. The outcomes comprised 7-day and 28-day mortality, and clinical and microbiological responses at 7 days, 28 days, and the end of treatment. Nephrotoxicity and hepatotoxicity were evaluated as drug adverse reactions. RESULTS: A total of 282 patients were included in the study. Among the CRAB strains, the two most susceptible antibiotics were colistin (99.6%) and minocycline (80.4%). A combination of colistin and carbapenem significantly reduced 7-day mortality, and a sulbactam-containing regimen significantly reduced 28-day mortality. Colistin monotherapy was significantly associated with increased 7-day and 28-day mortality. A minocycline-containing regimen showed the best microbiological responses at 7 days, 28 days, and the end of treatment. Colistin and tigecycline were associated with increased nephrotoxicity and hepatotoxicity, respectively. Subgroup analysis of patients with pneumonia showed similar results to the overall CRAB infection. CONCLUSIONS: A combination of colistin and carbapenem and sulbactam-containing regimen may contribute improved mortality in CRAB infections. Colistin monotherapy should be considered cautiously in severe CRAB infections or CRAB pneumonia. A minocycline-containing regimen showed the best microbiological responses, and further studies may be needed to evaluate improved mortality.

Tratamiento exitoso de la ventriculitis por Acinetobacter baumanii multidrogo resistente con colistina intravenosa e intraventricular / Successful treatment of ventriculitis due to multidrug resistant Acinetobacter baumanii with intravenous and intraventricular colistin

RESUMEN Las infecciones del sistema nervioso central asociadas a dispositivos como el drenaje ventricular externo son frecuentes. Sin embargo, la ventriculitis por bacterias Gram negativas y resistentes a antibióticos genera un reto para el tratamiento médico y quirúrgico. Se presenta el caso de un paciente con diagnóstico de malformación arteriovenosa rota con hemorragia intraventricular que requirió la colocación de un dren ventricular externo. En la evolución posterior, desarrolló ventriculitis por Acinetobacter baumanii multidrogo resistente (MDR) confirmada por cultivos de líquido cefalorraquídeo y se procedió a tratamiento antibiótico dirigido por antibiograma, usando colistina endovenosa e intraventricular asociando meropenem, logrando la normalización de los valores de LCR. Además describimos la evolución clínica, tratamiento médico-quirúrgico y complicaciones asociadas durante su estancia en la unidad de cuidados intensivos.

SUMMARY Central nervous system infections associated with devices such as external ventricular drains are frequent. Ventriculitis due to multi drug resistant (MDR) Gram-negative bacteria represent a surgical and medical challenge. We present the case of a patient who presented with intraventricular hemorrhage due to a rupture of an arteriovenous malformation that needed the insertion of an external ventricular drainage. The patient subsequently developed ventriculitis due to a MDR Acinetobacter baumanii confirmed by isolation from the cerebral spinal fluid (CSF) hat was treated based on the drug susceptibility test with intravenous and intraventricular colistin plus meropenem achieving normalization of the CSF parameters. We report the clinical evolution, complications and medical-surgical treatment in the intensive care unit.

Antibacterial resistance patterns of Acinetobacter baumannii complex: The results of Isfahan Antimicrobial Resistance Surveillance-1 Program

Objective: To determine the antibiotic resistance patterns of the Acinetobacter (A.) baumannii complex isolates that cause the confirmed infection. Methods: The present descriptive study was performed from March 2016 to March 2018 in three referral hospitals in Isfahan, Iran. All A. baumannii complex strains isolated from different clinical samples were identified by conventional phenotypic methods and antibiotic susceptibility pattern was detected. After the clinical investigation, contaminated samples were excluded and the source (hospital/community) and site of the infection were determined. Data on antibiotic susceptibility testing were extracted from WHONET software and analysis was done with SPSS. Results: From 254 patients who had confirmed A. baumannii complex infection, 158 (62.20%) cases were male, 27 (10.63%) were less than 20 years old, 172 (67.72%) had healthcare-Associated infections and 96 (37.79%) were admitted in intensive care units. The most frequent infection was bloodstream infections (111, 43.70%). Our results showed that most of the isolates were resistant to most of the antibiotics (more than 75.00%) and a lower rate of non-susceptibility was observed against minocycline (20, 44.44%) and colistin (0%). The rate of multidrug-resistant isolates was 88.97%. There was no significant difference between resistance of A. baumannii complex isolates according to age. However, the resistance to amikacin and minocycline and the rate of multidrug resistance (MDR) were significantly different between males and females. In patients with healthcare associated infection (HAI), MDR isolates were significantly different regarding admission in ICU ward. Resistance to levofloxacin and ciprofloxacin were lower in isolates from patients with bloodstream infections in comparison to other diagnoses. Conclusions: In our study, a high level of antibiotic resistance was detected in both community-Acquired and healthcare-Associated A. baumannii complex infections. Appropriate antibiotic prescription in a clinical setting is an essential need for the control and prevention of A. baumannii resistant infections.

Aislamientos de Acinetobacter en pacientes ingresados en Unidades de Cuidados intensivos / Isolation of Acinetobacter in patients admitted to Intensive Care Units

Fundamento: en los últimos años, las bacterias del género Acinetobacter han adquirido importancia epidemiológica de forma gradual y ascendente, debido a su emergencia como patógeno oportunista. Objetivo: caracterizar los aislamientos microbiológicos de Acinetobacter en pacientes ingresados en Unidades de Cuidados Intensivos en el Hospital Provincial de Cienfuegos. Métodos: estudio descriptivo que incluyó los 231 aislamientos de Acinetobacter de las muestras provenientes de pacientes de las Salas de Cuidados Intensivos en el período del 1 de septiembre del 2015 hasta el 30 de septiembre del 2016 en el Hospital Provincial de Cienfuegos. Se analizaron las variables: salas de dónde provenía el aislamiento, tipo de muestra, susceptibilidad antimicrobiana in vitro, especie. Resultados: el mayor número de aislamientos de Acinetobacter se obtuvo en la Unidad de Cuidados Intensivos Polivalentes (62,3 %). Acinetobacter baumannii fue la especie más aislada en todos los servicios para un 92,2 %; las secreciones respiratorias fueron las muestras con más aislamientos(56,3 %). Más de un 80 % de los aislamientos fueron resistentes a la mayoría de los antibióticos β-lactámicos y se encontró un porciento elevado de cepas multirresistencia y panrresistencia(41,6 % y 48,1 % respectivamente).Conclusiones: el género Acinetobacter se encuentra vinculado a las infecciones asociadas a los Servicios Sanitarios, fundamentalmente el Acinetobacter baumannii y en los cuidados intensivos polivalentes.

Foundation: in the last years bacterias of the Acinetobacter gender have adquired great epidemiological relevance in gardual ascending way, due to its emergence as an opportunistic pathogen. Objective: to characterize microbiological isolations of Acinetobacter in patients admitted to the Intensive Care Units at the Provincial Hospital Dr Gustavo Aldereguia Lima. Methods: descriptive study which included the 231 Acinetobacter isolations of samples from Intensive Care Units in the period September 1st 2015 to September 30th 2016 in the Cienfuegos Provincial Hospital. The following variables were analyzed: Wards from which the isolation was coming from, type of sample, antimicrobial susceptibility in vitro and specie. Results: the highest number of Acinetobacter isolations was obtained at the Polyvalent Intensive Care Unit (62,3%). Acinetobacter baumannii was the most isolated specie with a 92,2%. Respiratory exudate were the samples with more isolations (53,3%). More than 80% of the isolations were resistant to most β-lactam antibiotics and it was found a high percentage of multi-drug and pan-drug resistant strains (41,6% and 48,1% respectively).Conclusion: the Acinetobacter gender is linked to infections connected to Sanitary Services mainly the Acinetobacter baumannii and in the Intensive Care Units.

Positive effect of restrictions on antibiotic consumption

Background/aim: This study aimed to examine the change in the etiology of hospital infections with restricting and releasing of group 2 carbapenems (G2C) (meropenem/imipenem/doripenem). Materials and methods: This study was planned in three periods. Study period 1 (SP-1): Carbapenems were prescribed without restriction by infectious disease specialists. SP-2: G2C prescription was restricted. SP-3: Carbapenem prescription was released. Results: In total, 4443 cases [1053 in SP-1 (23.7%), 1332 in SP-2 (29.9%), and 2085 in SP-3 (46.9%)] were included in the study. Infection rates were 11%, 6.5%, and 7.9% in SP-1, SP-2, and SP-3, respectively (P = 0.001). Acinetobacter spp.-related hospital infection rates were 3.9%, 1.2%, and 1.8%, in SP-1, SP-2, and SP-3, respectively (P = 0.0001). Infection related mortality in SP-1, SP-2, and SP-3 was 7.3%, 5%, and 3.8%, respectively (P = 0.001). Conclusion: Hospital-acquired Acinetobacter infections, antibiotic consumption, and infection-related mortality were decreased significantly with the restriction of G2C. Positive behaviors that were obtained during the restricted period were continued with release of restriction.

Carbapenem-Nonsusceptible Acinetobacter baumannii, 8 US Metropolitan Areas, 2012-2015.

In healthcare settings, Acinetobacter spp. bacteria commonly demonstrate antimicrobial resistance, making them a major treatment challenge. Nearly half of Acinetobacter organisms from clinical cultures in the United States are nonsusceptible to carbapenem antimicrobial drugs. During 2012-2015, we conducted laboratory- and population-based surveillance in selected metropolitan areas in Colorado, Georgia, Maryland, Minnesota, New Mexico, New York, Oregon, and Tennessee to determine the incidence of carbapenem-nonsusceptible A. baumannii cultured from urine or normally sterile sites and to describe the demographic and clinical characteristics of patients and cases. We identified 621 cases in 537 patients; crude annual incidence was 1.2 cases/100,000 persons. Among 598 cases for which complete data were available, 528 (88.3%) occurred among patients with exposure to a healthcare facility during the preceding year; 506 (84.6%) patients had an indwelling device. Although incidence was lower than for other healthcare-associated pathogens, cases were associated with substantial illness and death.

Characterization of multidrug-resistant Acinetobacter ssp. strains isolated from medical intensive care units in Cali - Colombia / Caracterización de cepas de Acinetobacter spp. resistentes a múltiples fármacos aisladas de unidades de cuidados intensivos en Cali - Colombia

Abstract Introduction: The extensive use of antibiotics has led to the emergence of multi-resistant strains in some species of the genus Acinetobacter. Objective: To investigate the molecular characteristics of multidrug-resistant of Acinetobacter ssp. strains isolated from 52 patients collected between March 2009 and July 2010 in medical intensive care units in Cali - Colombia. Methods: The susceptibility to various classes of antibiotics was determined by disc diffusion method, and the determination of the genomic species was carried out using amplified ribosomal DNA restriction analysis (ARDRA) and by sequencing of the 16s rDNA gene. Also, the genes of beta-lactamases as well as, integrases IntI1 and IntI2 were analyzed by PCR method. Results: The phenotypic identification showed that the isolates belong mainly to A. calcoaceticus- A. baumannii complex. All of them were multi-resistant to almost the whole antibiotics except to tigecycline and sulperazon, and they were grouped into five (I to V) different antibiotypes, being the antibiotype I the most common (50.0%). The percent of beta-lactamases detected was: blaTEM (17.3%), blaCTX-M (9.6%), blaVIM (21.2%), blaIMP (7.7%), blaOXA-58 (21.2%), and blaOXA-51 (21.2%). The phylogenetic tree analysis showed that the isolates were clustering to A. baumannii (74.1%), A. nosocomialis (11.1%) and A. calcoaceticus (7.4 %). Besides, the integron class 1 and class 2 were detected in 23.1% and 17.3% respectively. Conclusion: The isolates were identified to species A. baumanii mainly, and they were multiresistant. The resistance to beta-lactams may be by for presence of beta-lactamases in the majority of the isolates.

Resumen Introducción: El uso extensivo de antibióticos ha llevado a la emergencia de cepas multirresistentes en algunas especies del género Acinetobacter. Objetivo: Investigar las características moleculares de resistencia a múltiples fármacos de cepas aisladas de Acinetobacter spp. colectadas entre marzo de 2009 y julio de 2010 en 52 pacientes de unidades de cuidados intensivos en Cali - Colombia. Métodos: La susceptibilidad a diversas clases de antibióticos se determinó mediante el método de difusión de disco, y la determinación de la especie genómica se llevó a cabo usando un análisis de restricción de ADN ribosómico amplificado (ARDRA) y mediante la secuenciación del gen 16s de ADNr. Además, se analizaron por el método de PCR los genes de las beta-lactamasas, como también, las integrasas IntI1 e IntI2. Resultados: La identificación fenotípica mostró que los aislamientos pertenecen principalmente al complejo A. calcoaceticus - A. baumannii. Todos ellos eran multirresistentes a casi todos los antibióticos excepto tigeciclina y sulperazón, y se agruparon en cinco (I a V) antibitipos diferentes, siendo el antibiotipo I el más común (50%). El porcentaje de betalactamasas detectadas fue: blaTEM (17,3%), blaCTX-M (9,6%), blaVIM (21,2%), blaIMP (7,7%), blaOXA-58 (21,2%), blaOXA- 51 (21.2%). El análisis del árbol filogenético mostró que los aislados se agrupaban en A. baumannii (74.1%), A. nosocomialis (11.1%) y A. calcoaceticus (7.4%). Además, el integrón clase 1 y clase 2 se detectaron en 23.1% y 17.3% respectivamente. Conclusión: los aislamientos se identificaron principalmente como la especie A. baumanii, y fueron multirresistentes. La resistencia a los betalactámicos puede deberse a la presencia de betalactamasas en la mayoría de los aislamientos.

Characterization of multidrug-resistant Acinetobacter ssp. strains isolated from medical intensive care units in Cali - Colombia.

INTRODUCTION: The extensive use of antibiotics has led to the emergence of multi-resistant strains in some species of the genus Acinetobacter. OBJECTIVE: To investigate the molecular characteristics of multidrug-resistant of Acinetobacter ssp. strains isolated from 52 patients collected between March 2009 and July 2010 in medical intensive care units in Cali - Colombia. METHODS: The susceptibility to various classes of antibiotics was determined by disc diffusion method, and the determination of the genomic species was carried out using amplified ribosomal DNA restriction analysis (ARDRA) and by sequencing of the 16s rDNA gene. Also, the genes of beta-lactamases as well as, integrases IntI1 and IntI2 were analyzed by PCR method. RESULTS: The phenotypic identification showed that the isolates belong mainly to A. calcoaceticus- A. baumannii complex. All of them were multi-resistant to almost the whole antibiotics except to tigecycline and sulperazon, and they were grouped into five (I to V) different antibiotypes, being the antibiotype I the most common (50.0%). The percent of beta-lactamases detected was: blaTEM (17.3%), blaCTX-M (9.6%), blaVIM (21.2%), blaIMP (7.7%), blaOXA-58 (21.2%), and blaOXA-51 (21.2%). The phylogenetic tree analysis showed that the isolates were clustering to A. baumannii (74.1%), A. nosocomialis (11.1%) and A. calcoaceticus (7.4 %). Besides, the integron class 1 and class 2 were detected in 23.1% and 17.3% respectively. CONCLUSION: The isolates were identified to species A. baumanii mainly, and they were multiresistant. The resistance to beta-lactams may be by for presence of beta-lactamases in the majority of the isolates.

INTRODUCCIÓN: El uso extensivo de antibióticos ha llevado a la emergencia de cepas multirresistentes en algunas especies del género Acinetobacter. OBJETIVO: Investigar las características moleculares de resistencia a múltiples fármacos de cepas aisladas de Acinetobacter spp. colectadas entre marzo de 2009 y julio de 2010 en 52 pacientes de unidades de cuidados intensivos en Cali - Colombia. MÉTODOS: La susceptibilidad a diversas clases de antibióticos se determinó mediante el método de difusión de disco, y la determinación de la especie genómica se llevó a cabo usando un análisis de restricción de ADN ribosómico amplificado (ARDRA) y mediante la secuenciación del gen 16s de ADNr. Además, se analizaron por el método de PCR los genes de las beta-lactamasas, como también, las integrasas IntI1 e IntI2. RESULTADOS: La identificación fenotípica mostró que los aislamientos pertenecen principalmente al complejo A. calcoaceticus - A. baumannii. Todos ellos eran multirresistentes a casi todos los antibióticos excepto tigeciclina y sulperazón, y se agruparon en cinco (I a V) antibitipos diferentes, siendo el antibiotipo I el más común (50%). El porcentaje de betalactamasas detectadas fue: blaTEM (17,3%), blaCTX-M (9,6%), blaVIM (21,2%), blaIMP (7,7%), blaOXA-58 (21,2%), blaOXA- 51 (21.2%). El análisis del árbol filogenético mostró que los aislados se agrupaban en A. baumannii (74.1%), A. nosocomialis (11.1%) y A. calcoaceticus (7.4%). Además, el integrón clase 1 y clase 2 se detectaron en 23.1% y 17.3% respectivamente. CONCLUSIÓN: los aislamientos se identificaron principalmente como la especie A. baumanii, y fueron multirresistentes. La resistencia a los betalactámicos puede deberse a la presencia de betalactamasas en la mayoría de los aislamientos.

An update on the arsenal for multidrug-resistant Acinetobacter infections: polymyxin antibiotics.

OBJECTIVE: To review recent clinical pharmacokinetic and pharmacodynamic data to optimize dosing regimens for polymyxin B and colistin for treatment of infections due to A. baumannii. METHODS: A literature search was performed using the search terms Acinetobacter, polymyxin, colistin, polymyxin B on MEDLINE. Additional references were identified from the resulting citations. RESULTS: Increasing the dose of polymyxin B or colistin and using either in combination with other antibiotic agents demonstrates improved antimicrobial activity against Acinetobacter spp. Polymyxin B, unlike colistin, is available as an active drug and appears to be relatively unaffected by renal function. This is advantageous both for patients with renal impairment and for those with intact renal function. Achieving therapeutic serum concentrations of colistin may be difficult for those with intact renal function due to rapid clearance of the prodrug, colistimethate sodium (CMS). Clinical data are still lacking for polymyxin B, and it remains to be seen whether advantages demonstrated in PK/PD analyses will persist in the larger scale of patient care and safety. CONCLUSIONS: The use of higher doses of either colistin or polymyxin B, as well as combination with other antibiotics, may prevent emerging resistance and preserve the activity of polymyxins against A. baumannii.

Management of mycotic femoral artery aneurysm with two resistant organisms.

We report the management of a case of thigh abscess with ruptured left superficial femoral artery mycotic aneurysm in a 91-year-old woman with significant comorbidity. The abscess culture grew Escherichia coli and Acinetobacter baumannii. Vascular reconstruction was not performed because the foot was viable with a heavily contaminated wound. The thigh wound healed with the help of vacuum-assisted closure. This is the first report of a ruptured mycotic aneurysm of the superficial femoral artery associated with Escherichia coli and Acinetobacter baumannii infection. This case demonstrates that resection of a mycotic aneurysm without vascular continuity is feasible, especially in frail patients.

Community-acquired necrotizing fasciitis caused by Acinetobacter calcoaceticus: a case report and literature review.

A 61-year-old man presented with pain in the abdomen and right lower limb. He had a history of hepatitis B virus-induced liver cirrhosis, but had not been visiting the outpatient clinic and did not receive any medication. Cutaneous necrosis and bulla were observed on his abdomen and right lower limb. The necrotic skin was incised, and he was diagnosed with necrotizing fasciitis. A nonfermentative Gram-negative bacillus infection was confirmed from aspirated fluid and blood cultures. Therefore, meropenem and immunoglobulins were administered. Because necrosis was widespread, surgical debridement was performed. Thereafter, Acinetobacter calcoaceticus infection was confirmed by semi-quantitative PCR using the bullous fluid and blood cultures. Meropenem was administered for 3 weeks, followed by levofloxacin alone for 1 week. The patient's condition improved; therefore, skin grafting was performed as planned and yielded a favorable response. After rehabilitation, the patient could walk without support and infection did not recur. However, he had severe liver cirrhosis and large esophageal varices, and he eventually died from sudden varix rupture. Necrotizing fasciitis is an uncommon soft tissue infection, associated with high morbidity and mortality, and early recognition and treatment are crucial for survival. Acinetobacter is rarely associated with necrotizing fasciitis. Although this is a very rare case of the occurrence of necrotizing fasciitis due to A. calcoaceticus infection, we believe that this organism can be pathogenic in immunocompromised patients such as those with liver cirrhosis by reporting this case.

Resistance and infection case analysis for multidrug-resistant Acinetobacter baumannii / 中华检验医学杂志

Objective To investigate the resistance and infection case for the Multidrug-Resistant Acinetobacter baumanii (MDRAb) strains.Methods Retrospective study.Thirty-eight MDRAb strains were collected in Beijing Friendship Hospital from February to August 2008.VITEK2-compact system was used to detect the MDRAb.PCR was carried out to detect their resistance related genes and look up the medical records those who were infected by MDRAb.Results The resistance rate of the MDRAb is the highest in ICU.PCR confirmed that OXA-23 and OXA-51 were 100％ related with the MDRAb.Combination drug therapy such as sulbactam combined with β-lactam antibiotics was more effective than β-lactam antibiotics only to treat the infection with MDRAb.Cases analysis showed that a number of patients infected by MDRAb were the aged with basic diseases,low immunity,received a variety of antibiotic therapy even traumatic operation,and they had a poor prognosis finally.Conclusions The resistance rate of the MDRAb is the highest in ICU,OXA-23 is closely related to multidrug-resistance.Combination drug therapy is necessary and sulbactam can play a great role in curing the inpatients infected with MDRAb.

Systematic review of invasive Acinetobacter infections in children.

INTRODUCTION: Clinicians are generally familiar with Acinetobacter as an etiological agent for serious nosocomial infections in intensive care units. However, there are no previous reviews of the full spectrum of invasive infections in children. METHODS: A systematic review of the literature was completed up to December 2008 for reports of invasive Acinetobacter infections in children. RESULTS: There were 101 studies that met the inclusion criteria including 18 possible outbreaks, 33 case series and 49 case reports. Suspected outbreaks were concentrated in neonatal intensive care units (16 of 18 outbreaks) and involved bacteremia or meningitis. Proof of isolate clonality or identification of the source of the outbreak was seldom established. Case series were primarily of children younger than five years of age presenting with bacteremia (sometimes multiresistant), meningitis, endocarditis or endophthalmitis, with many community-acquired infections being reported from India. Case reports consisted of unique presentations of disease or the use of novel therapies. Attributable mortality in the outbreaks and case series combined was 68 of 469 (14.5%). DISCUSSION: Invasive Acinetobacter infections in children usually manifest as bacteremia, meningitis or both, but can result in a wide variety of clinical presentations. Outbreaks are primarily a problem in newborns with underlying medical conditions. Most reports of community-acquired infections are from tropical countries. The study of the mechanism of colonization and infection of children in intensive care units and of neonates in tropical countries may provide some insight into prevention of invasive infections.

Establishment of mice pneumonia model with imipenem-resistant Acinetobacter baumannii / 中华检验医学杂志

Objective To construct the mice pneumonia model with imipenem-resistant Acinetobacter baumannii and provide experimental model in anti-pan-resistant Acinetobacter baumannii therapy study. Methods A total number of 120 4-week-old BALB/C male mice were randomly selected and divided into three groups including micro-intratracheal injection, ultrasonic atomizing and nasal dripping. The mice were treated with methotrexate to induce hypo-immunity in every group. These BALB/C mice of normal immunity and hypo-immunity were infected through Imipenem-resistant Acinetobacter baumannii by microintratracheal injection, ultrasonic atomizing and nasal dripping, respectively. The morbidity, mortality,bacterial clearance rate and histopathology in lung were determined. Results The morbidities of BALB/C mice with hypo-immunity infected by micro-intratracheal injection and ultrasonic atomizing achieved 100%(30/30), while the mortalities were 100% (10/10) and 33.3% (3/10), respectively. Mice in two groups above displayed the influx of neutrophils, lymphocytes and macrophages in the peri-bronchial and alveolar interstitial space 12-24 h after pulmonary infection. In addtion, the mice in micro-intratracheal injection group displayed coUapse of partial alveolar walls, formation of abscesses and bacterial colonies in alveoli. While the lung pathology in mice of ultrasonic atomizing group was characterized by cell degeneration in some regions in the lungs, slight relaxation, congestion in alveolar wall vessels and normal of bronchial and alveolar tissue 24 h after inoculation. Degeneration in peri-tracheal and peri-bronchial areas was observed 24-48 h after inoculation, along with highly expanded pulmonary blood vessels and edems. The inflammation was reduced at 48 hours. There was no obvious pulmonary infection in BALB/C mice with hypo-immunity by nasal dripping with mortality of 0% (0/10) and no significant histopathologic change in lungs. Conclusions BALB/C mice with hypo-immunity pneumonia model with Imipenem-resistant Acinetobacter baumannii can be conducted by micro-intratracheal injection or ultrasonic atomizing, but the latter has the advantages of high-productivity, easy-operation, low-cost, time-saving and usefulness. Mice with normal immunity are not susceptible to imipenem-resistant Acinetobacter baumannii.

Clinical analysis of 72 cases with lower respiratory tract acinetobacterial infection / 中国基层医药

Objective To explore the clinical features,risk factors and the sensitivity to antibiotics of lower respiratory tract acinetobacterial infection.Methods The clinical data,results of sputum bacterial culture and drug sensitivity of the 72 cases with lower respiratory tract acinetobacterial infection were netrospectively reviewed.Results 53 cases(73.6%)were elder than 60 years old,69 cases(95.8%)had basic diseases,and 59 cases(81.9%)were nosocomial infection.Risk factors included basic diseases,lower immune function,all kinds of invasive operations,aerosol inhalation,unreasonable usage of antibiotics.Drug sensitivity test showed that the drugs which sensitive to acinetobacter was upper than 50% included Imipenen,Levofloxacin,Cefooerazone/sulbactum and Amikacin.Conclusion The patients who sufferred from lower respiratory tract acinetobacterial infection usually are elder than 60 years old,and have basic diseases.Most of this kind of infection is nosocomial infection.Because of severe clinical symptom and high drug resistant rate,the prognosis is poor.Reasonable selection of sensitive antibiotics is important.