The impact of COVID-19 on microbiological profile and antibiotic consumption in ICU: a retrospective study in an infectious disease hospital in Brazil

Abstract Background The COVID-19 pandemic has triggered crises in the public health sector that have complex and multifaceted interrelationships with antimicrobial resistance. It is important to evaluate the impact of COVID-19 on microbiological profile, antibiotic and alcohol gel consumption in Intensive Care Units (ICU). Methods This is a retrospective study undertaken in an infectious disease hospital located in Bahia/Brazil during three periods: from March 2019 to February 2020; from March 2020 to February 2021; and from March 2021 to February 2022. It was evaluated the incidence density of Candida spp and of multidrug-resistant Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species (ESKAPE group) in blood, urine and tracheal secretion isolated 48 h after the patient's admission to the ICU, as well as the use of alcohol gel (in milliliters) and consumption of antibiotics in Defined Daily Dose (DDD) per 1,000 ICU patient-days in the previous year and in the first two years of COVID-19 pandemic. Results There was an increase in Candida spp. (5.81, p < 0.001, IRR = 10.47, 95 % CI 2.57‒42.62) and in carbapenem-resistant A. baumannii in clinical cultures (4.71, p < 0.001, IRR = 8.46, 95 % CI 2.07‒34.60), the latter mainly in tracheal secretions (3.18, p =0.02, IRR = 11.47, 95 % CI 1.58‒83.39). A rise in the consumption of ceftriaxone and piperacillin-tazobactam, along with an increase in the utilization of alcohol gel were observed. Conclusion The shifting microbiological profile can be attributed to both the unique characteristics of patients with COVID-19 and the adjustments made to healthcare facilities' structural and work routines. Understanding these changes is essential in addressing the accelerated impact of antimicrobial resistance during the pandemic. Therefore, conducting thorough reviews of institutional practices and routines becomes critical in mitigating the consequences of antimicrobial resistance and its implications for patient care.

Bacteriophages as therapeutic & disinfectant agents to tackle multidrug-resistant Acinetobacter baumannii

Background & objectives: Multidrug-resistant (MDR) Acinetobacter baumannii is a serious threat for human health worldwide. The studies on agents targeting A. baumannii are imperative due to identified A. baumannii co-infections in COVID-19. Bacteriophages are promising antibacterial agents against drug-resistant bacteria. This study intended to isolate bacteriophages against MDR A. baumannii from the water of river Ganga, to be used potentially as therapeutic and disinfectant particles. Methods: Acinetobacter phages were isolated from the Ganga water collected from Kanpur and further tested on 50 MDR A. baumannii isolates to determine host range. The phages were morphologically characterized by transmission electron microscopy. The disinfectant property of the isolated phages was tested by spraying of bacteriophage cocktail on MDR A. baumannii contaminated plastic surface, analyzed by colony-forming unit (CFU) and bioluminescence assay (adenosine triphosphate monitoring). Results: A total of seven bacteriophages were isolated against MDR A. baumannii. The bacteriophages lysed three MDR A. baumannii isolates out of 50 tested, showing narrow host range. Electron microscopy revealed hexagonal heads and long tails of bacteriophages, belonging to order Caudovirales. The bacteriophage cocktail reduced the MDR A. baumannii load efficiently on plastic surface, evidenced by reduction in CFUs and bioluminescence. Interpretation & conclusions: The findings of this study suggest that the isolated bacteriophages are potential lytic agents for MDR A. baumannii clinical isolates, and may be used as potential therapeutic agents as well as disinfectant to combat MDR A. baumannii with due consideration to phage host specificity, with further characterization.n

A Rapid Method to Screen for Multi Drug Resistance (MDR) Trait in Clinical Isolates of Acinetobacter baumannii-Acyl Homoserine Lactone (AHL) Screening in CRAB and CSAB Isolates

Aims: Our proposal aimed to evaluate Acyl Homoserine Lactones (AHL) as a functional marker for Multi drug resistant (MDR) potential in clinical isolates of Acinetobacter baumannii. We investigated the AHL production potential of clinical isolates using a biosensor assay directly on a commonly used agar media. Place and Duration of Study: Department of Molecular Diagnostics and Biomarkers, Gleneagles Global Hospitals, Lakdikapul, Hyderabad-500004. Methodology: Antimicrobial drug sensitivity testing (AST) was performed on 72 clinical isolates of A. baumannii against two front-line antibiotics, Imipenem (10µg) and Meropenem (10µg), by Kirby-Bauer disk diffusion method. Production of long chain Acyl Homoserine lactone (AHLs) in the clinical isolates of A. baumannii was tested by cross streaking with the biosensor Chromobacterium violaceum mutant strain CV026 and Agrobacterium tumefaciens (NTL4pZLR4) by agar plate diffusion assay. Screening and identification of the quorum sensing mediator gene abaI was done by PCR to confirm its presence in all the 72 clinical isolates. Results: Out of the 72 clinical isolates, 58 were Carbapenem resistant Acinetobacter baumannii (CRAB) and 14 were Carbapenem sensitive Acinetobacter baumannii (CSAB) for AST by agar disc diffusion method. None of our isolates produced short chain AHLs whereas all the isolates could produce varying amounts of long chain AHLs. Genotypic confirmation of AHL gene was obtained by abaI gene PCR. Conclusion: Carbapenems are the front-line antibiotics used to treat gram negative bacterial infections in emergencies and in the critical care units of hospitals. Clinical isolates A. baumannii has innate resistance to several antibiotics due to various mechanisms, biofilms forming the first line of defense against antibiotics for the bacterium. Our study used AST to carbapenem as the leading marker for MDR, assuming the innate resistance of A. baumannii to other beta lactam antibiotics. Our study brought out certain important observations namely: a) All clinical isolates of A. baumannii produced Quorum Sensing signal molecules, the AHLs b) the clinical isolates of A. baumannii did not produce any short chain AHLs b) All the clinical isolates of A. baumannii produced long chain AHLs c) AHL production is not specific to carbapenem drug resistance because even CSAB isolates produced AHL d) AHL production is inherent to all clinical isolates of A. baumannii and it apparently indicates an underlying biofilm potential and MDR trait in these A. baumannii isolates. e) AHLs could be a universal marker for revealing MDR trait and biofilm potential in clinical microbiology AST profiling protocols.

Meningitis posquirúrgica por Acinetobacter baumannii multirresistente. Actividad sinérgica in vivo de la asociación sulbactam/avibactam / Post-surgical meningitis due to multiresistant Acinetobacter baumannii. In vivo synergistic activity of the sulbactam/avibactam association

Acinetobacter baumannii (AB) es un bacilo gram negativo, no fermentador,con frecuencia oportunista, ubicuo en el medio ambiente, con capacidad para sobrevivir en condiciones medioambientales adversas promoviendo su persistencia y diseminación en diferentes áreas de un hospital. Ha sido relacionado con múltiples brotes de infecciones asociadas al cuidado de la salud como neumonía, bacteriemias, contaminación de heridas quirúrgicas o infecciones del tracto urinario, especialmente entre pacientes con comorbilidades graves, como aquellos que motivan el ingreso a unidades de cuidados intensivos (UCI). Las cepas más problemáticas son aquellas resistentes a los carbapenémicos, resistencia causada por enzimas de la clase de las oxacilinasas (bla OXA) cromosómicas o plasmídicas y más recientemente bla NDM-1. La aparición de estas cepas deja escasos antimicrobianos activos (colistin, minociclina, tigeciclina; amikacina) que son limitados en su eficacia y su uso se asocia con toxicidad. A esto se agrega, como en la paciente que se describe, que desarrolló una meningitis posquirúrgica, la limitada capacidad de difusión en el sistema nervioso central (SNC) de estas últimas opciones. Una de las alternativas terapéuticas, es buscar asociaciones como sulbactam/avibactam que mostraron una adecuada actividad sinérgica y bactericida en asilamientos resistentes a ampicilina/sulbactam en base a una significativa reducción de la CIM que permite administrar dosis habituales, con mejor tolerancia y lograr concentraciones terapéuticas en SNC. Se presenta una paciente que desarrolló una meningitis posquirúrgica debida a una cepa de AB multirresistente.

Acinetobacter baumannii (AB) is a non-fermenting gram-negative bacillus, largely opportunistic, ubiquitous in the environment, with the ability to survive in adverse environmental conditions, promoting its persistence and dissemination in different areas of the hospital. It has been implicated in many outbreaks of healthcare-associated infections such as pneumonia, bacteremia, surgical wounds contamination, or urinary tract infections, especially among patients with previous severe illnesses such as those requiring admission to intensive care units (ICU). The most problematic strains are those resistant to carbapenems, resistance caused by chromosomal or plasmid oxacillinase class (bla OXA), and more recently bla NDM-1. The appearance of these strains leaves few active antimicrobials (Colistin, Minocycline, Tigecycline; Amikacin) that are limited in their efficacy and toxic. To this we must add, as is the case of our patient who presented post-surgical meningitis, the limited diffusion capacity in the central nervous system (CNS) of these last options. One of the therapeutic alternatives is to search for synergistic associations such as sulbactam/avibactam that showed rapid synergistic and bactericidal activity in isolates resistant to ampicillin/sulbactam due to a significant reduction in its MIC, which allows us to administer usual, better tolerated doses that reach therapeutic concentrations in CNS. Here, we present a patient who developed a post-surgical meningitis due to multiresistant AB

Infección respiratoria polimicrobiana: un caso de colonización multirresistente y coinfección viral en un lactante

Se presenta el caso de un lactante de 38 semanas ingresado con distrés respiratorio a un nosocomio al norte del Perú. Tras intubación y conexión a ventilación mecánica, se administró tratamiento antimicrobiano y sedoanalgesia. Durante la hospitalización, el paciente presentó fiebre, tos con expectoración quintosa, rubicundez facial y desaturación. Se observó edema en párpados, manos y pies, pero la perfusión tisular se mantuvo adecuada. En el cuarto día, sufrió convulsión febril, sibilancias respiratorias y oliguria con hematuria. Se realizaron cambios en el tratamiento y se administraron transfusiones. Al día 7, con apoyo del panel de PCR múltiple (FilmArray®) para el diagnóstico etiológico de enfermedades infecciosas respiratorias, se diagnosticó colonización/infección por Acinetobacter baumanni multirresistente, la cual se acompañó con la detección de Serratia marcescens y virus sincicial respiratorio. Tras una estancia prolongada se logró la extubación exitosa el día 10. El día 24, el paciente fue dado de alta sin fiebre, signos vitales estables y sin requerir oxígeno, solo tratamiento para las convulsiones.

A case is presented of a 38-week-old infant admitted with respiratory distress to a hospital in northern Perú. After intubation and connection to mechanical ventilation, antimicrobial treatment and sedoanalgesia were administered. During hospitalizaron, the patient experienced fever, cough with quintose expectoration, facial rubor, and desaturation. Edema was observed in the eyelids, hands, and feet, but tissue perfusion remained adequate. On the fourth day, the patient had a febrile seizure, respiratory wheezing, and oliguria with hematuria. Treatment changes were made, and transfusions were administered. On the seventh day, using the FilmArray® multiplex PCR panel for etiological diagnosis of respiratory infectious diseases, colonization/infection by multidrug-resistant Acinetobacter baumanni was diagnosed, accompanied by the detection of Serratia marcescens and respiratory syncytial virus. After a prolonged stay, successfu extubation was achieved on day 10. On day 24, the patient was discharged without fever, stable vital signs, and without requiring oxygen only treatment for seizures.

Ação antimicrobiana e antibiofilme dos extratos combinados de canela e própolis sobre cepas clínicas de Acinetobacter baumannii e Pseudomonas aeruginosa multirresistentes / Antimicrobial and antibiofilm action of combined extracts of cinnamon and propolis on multiresistant clinical strains of Acinetobacter baumannii and Pseudomonas aeruginosa

Os microrganismos resistentes a diferentes classes de agentes antimicrobianos têm se tornado cada vez mais comuns e atualmente são denominados como multirresistentes. Nos hospitais, tais microrganismos apresentam maior perigo, pois são causadores de infecções nosocomiais e a higienização bucal deficiente dos pacientes internados pode tornar a cavidade bucal um sítio para proliferação desses microrganismos multirresistentes. Diante do exposto, novos compostos com ação antimicrobiana precisam ser estudados. O objetivo deste estudo foi avaliar quimicamente o extrato hidroalcóolico de própolis verde de Baccharis dracunculifolia e de Cinnamomum verum (canela) que foram obtidos a partir da extração da matériaprima, analisar a atividade antimicrobiana e antibiofilme dos extratos isolados e combinados contra quatro cepas clínicas multirresistentes de Pseudomonas aeruginosa e Acinetobacter baumannii e verificar a citotoxicidade dos produtos vegetais in vitro em linhagem celular de queratinócitos humanos (HaCat). Para tanto, os extratos vegetais foram preparados a partir da matéria-prima da canela em casca e da própolis bruta. Em seguida, foram caracterizados quimicamente por cromatografia líquida de alta eficiência (HPLC-DAD) para identificação dos principais compostos e a análise do teor de sólidos solúveis dos extratos vegetais também foi realizada. Para avaliação antimicrobiana, foram performados o teste de microdiluição em caldo de acordo com a Clinical and Laboratory Standards Institute (CLSI) e a análise de Checkerboard, para avaliar o efeito combinado dos extratos. A atividade antibiofilme dos extratos combinados foi realizada por meio do teste de MTT, no qual diferentes tempos de contato (5 e 30 min) e diferentes modalidades (inibição na formação do biofilme bacteriano e erradicação do biofilme bacteriano já formado) foram testadas. Para ação citotóxica, as células foram cultivadas em meio DMEM e semeadas na placa de 96 poços. Após aderência inicial, aplicou-se os extratos em diferentes concentrações baseadas nas análises microbiológicas para avaliação da viabilidade celular por meio do teste de MTT. Os dados foram analisados por ANOVA e teste de Tukey, ou Kruskal-Wallis e Dunn, considerando um nível de significância de 5%. Os compostos identificados no extrato de própolis verde de B. dracunculifolia foram ácido clorogênico, derivado do ácido cinâmico e apigenina. O aldeído cinâmico foi o principal composto identificado no extrato de C. verum. Os extratos vegetais apresentaram ação bactericida sobre todas as cepas analisadas e, quando combinados, os extratos atuaram de modo aditivo e algumas combinações sinérgicas foram encontradas. O protocolo de inibição da formação do biofilme promoveu percentuais de redução superiores quando comparado ao protocolo de erradicação. Valores expressivos de 83,86% (p < 0,05) de inibição da formação de biofilme de uma cepa clínica de A. baumannii e 89,31% (p < 0,05) de inibição em uma cepa clínica de P. aeruginosa foram encontrados com a aplicação dos extratos combinados. A atuação dos produtos vegetais foi estatisticamente semelhante a atuação da clorexidina 0,12%. Em conclusão, os extratos de própolis verde e canela na forma isolada ou combinada apresentaram ação antimicrobiana e antibiofilme sobre cepas clínicas de A. baumannii e P. aeruginosa multirresistentes. Dessa forma, os produtos vegetais são promissores agentes antissépticos para futuras formulações odontológicas. (AU)

Microorganisms resistant to different classes of antimicrobial agents have become increasingly common and are currently called multidrug resistant. In hospitals, such microorganisms are more dangerous, as they cause nosocomial infections and poor oral hygiene in hospitalized patients can make the oral cavity a site for the proliferation of these multiresistant microorganisms. Given the above, new compounds with antimicrobial action need to be studied. The objective of this study was to chemically evaluate the hydroalcoholic extract of green propolis from Baccharis dracunculifolia and Cinnamomum verum (cinnamon) that were obtained from the extraction of the raw material, to analyze the antimicrobial and antibiofilm activity of the isolated and combined extracts against four clinical strains multiresistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii and verify the cytotoxicity of plant products in vitro in human keratinocyte cell lineage (HaCat). For this purpose, plant extracts were prepared from raw cinnamon bark and raw propolis. Then, they were chemically characterized by high performance liquid chromatography (HPLC-DAD) to identify the main compounds and the analysis of the soluble solids content of the plant extracts was also performed. For antimicrobial evaluation, the broth microdilution test according to the Clinical and Laboratory Standards Institute (CLSI) and the Checkerboard analysis were performed to evaluate the combined effect of the extracts. The antibiofilm activity of the combined extracts was performed using the MTT test, in which different contact times (5 and 30 min) and different modalities (inhibition of bacterial biofilm formation and eradication of already formed bacterial biofilms) were tested. For cytotoxic action, cells were cultured in DMEM medium and seeded in the 96-well plate. After initial adhesion, the extracts were applied at different concentrations based on microbiological analyzes to assess cell viability through the MTT test. Data were analyzed by ANOVA and Tukey's test, or Kruskal-Wallis and Dunn, considering a significance level of 5%. The compounds identified in the green propolis extract of B. dracunculifolia were chlorogenic acid, cinnamic acid derivative and apigenin. Cinnamic aldehyde was the main compound identified in the C. verum extract. The plant extracts showed bactericidal action on all strains analyzed and, when combined, the extracts acted additively and some synergistic combinations were found. The biofilm formation inhibition protocol promoted higher reduction percentages when compared to the eradication protocol. Significant values of 83.86% (p < 0.05) inhibition of biofilm formation in a clinical strain of A. baumannii and 89.31% (p < 0.05) inhibition in a clinical strain of P. aeruginosa were found with the application of the combined extracts. The performance of plant products was statistically similar to the performance of 0.12% chlorhexidine. In conclusion, extracts of green propolis and cinnamon, in isolated or combined form, showed antimicrobial and antibiofilm action on multiresistant clinical strains of A. baumannii and P. aeruginosa. Thus, plant products are promising antiseptic agents for future dental formulations. (AU)

Extratos hidroetanólicos de canela (Cinnamomum verum) e romã (Punica granatum L) promovem ação antibacteriana frente cepas resistentes a antibióticos de Acinetobacter baumannii e Pseudomonas aeruginosa / Cinnamon (Cinnamomum verum) and pomegranate (Punica granatum L) hydroethanolic extracts promote antibacterial action against antibiotic-resistant strains of Acinetobacter baumannii and Pseudomonas aeruginosa

A resistência bacteriana tem aumentado progressivamente no mundo, assim, há necessidade de novas opções de tratamentos. A fitoterapia tem ganhado notoriedade para combater infecções, principalmente as causadas por bactérias resistentes aos antibacterianos disponíveis. Diante do exposto, o presente estudo teve como objetivo preparar e analisar a composição fitoquímica e a ação antibacteriana dos extratos hidroetanólicos de canela (EHC) e romã (EHR) isolados e associados frente culturas planctônicas e biofilmes de cepas padrão e clínicas de Acinetobacter baumannii e Pseudomonas aeruginosa, além disso, analisar a ação citotóxica dos extratos em queratinócitos humanos (HaCat). Para isso, os EHC e EHR foram preparados e quantificado o teor de sólidos solúveis. Posteriormente, foi quantificado o teor de flavonoides e fenóis totais, análise antioxidante por meio da redução do radical 2,2'-difenil-1-picrilhidrazila (DPPH), e a fitoquímica por cromatografia líquida (HPLC). Em relação a ação antibacteriana dos extratos, foi aplicado o teste de microdiluição em caldo (CLSI ­ M7-A9) e a ação sinérgica realizada por meio do ensaio de checkerboard. As concentrações mais efetivas foram analisadas sobre biofilmes em formação (prevenção) e biofilmes formados (tratamento de 24 h), e quantificada a viabilidade por meio do teste colorimétrico MTT. Para avaliar a citotoxidade, os tratamentos foram aplicados sobre cultura celular de HaCat por 24 h e analisados por meio do teste colorimétrico MTT. A análise estatística foi realizada com 5% de significância (p<0.05), analisados pelo método ANOVA complementado pelo Teste de Tukey. Os resultados demonstraram que os EHC e EHR possuem ação antioxidante e presença de fitocompostos. Os extratos apresentaram ação antibacteriana para todas as cepas avaliadas, quando os mesmos foram associados, obteve-se concentrações sinérgicas para as cepas clínicas de A. baumannii. Em relação a ação antibiofilme, o EHC inibiu a formação em 95% e EHR em 96% do biofilme de #Ab 1, enquanto a cepa #Pa 2 teve 92% e 93% de inibição quando em contato com EHC e EHR, respectivamente. Após tratamento de 24 h em biofilmes formados, as reduções da viabilidade foram de 72% para as cepas #Ab 2 e #Ab 3 quando em contato com o EHC, já EHR inibiu em 83% a viabilidade da cepa #Ab ATCC. Para P. aeruginosa (#Pa 2), as reduções da viabilidade foram de 84% e 88,5% quando tratados com EHC e EHR, respectivamente. A avaliação da citotoxicidade em HaCat demonstrou que após tratamentos com diferentes concentrações dos extratos a viabilidade celular se manteve acima de 70% em todos os grupos. Diante disso, conclui-se que os EHC e EHR apresentam importante ação antioxidante e antibacteriana, tanto em culturas planctônicas quanto em biofilmes, e não apresentaram efeitos citotóxicos na faixa de concentração testada. (AU)

Bacterial resistance has progressively increased in the world, thus, there is a need for new treatment options. Phytotherapy has gained notoriety for fighting infections, mainly those caused by bacteria resistant to available antibacterials. In view of the above, the present study aimed to prepare and analyze the phytochemical composition and antimicrobial action of hydroethanolic extracts of cinnamon (EHC) and pomegranate (EHR) isolated and associated against planktonic cultures and biofilms of standard and clinical strains of Acinetobacter baumannii and Pseudomonas aeruginosa, in addition, analyze the cytotoxic action of the extracts on human keratinocytes (HaCat). For this, the EHC and EHR were prepared and the soluble solids content was quantified. Subsequently, the content of flavonoids and total phenols, antioxidant analysis through the reduction of the radical 2,2'-diphenyl1-picrylhydrazyl (DPPH), and phytochemistry by liquid chromatography (HPLC) were quantified. Regarding the antimicrobial action of the extracts, the broth microdilution test (CLSI ­ M7-A9) was applied and the synergistic action was performed through the checkerboard test. The most effective concentrations were analyzed on forming biofilms (prevention) and formed biofilms (24 h treatment), and viability was quantified using the MTT colorimetric test. To evaluate the cytotoxicity, the treatments were applied on HaCat cell culture for 24 h and analyzed using the MTT colorimetric test. Statistical analysis was performed with 5% significance (p<0.05), analyzed by the ANOVA method complemented by the Tukey test. The results showed that the EHC and EHR have antioxidant action and presence of phytocompounds. The extracts showed antibacterial action for all evaluated strains, when they were associated, synergistic concentrations were obtained for the clinical strains of A. baumannii. Regarding the antibiofilm action, EHC inhibited formation by 95% and EHR by 96% of the #Ab 1 biofilm, while the #Pa 2 strain had 92% and 93% inhibition when in contact with EHC and EHR, respectively. After 24 h treatment in formed biofilms, viability reductions were 72% for strains #Ab 2 and #Ab 3 when in contact with EHC, whereas EHR inhibited the viability of strain #Ab ATCC by 83%. For P. aeruginosa (#Pa 2), viability reductions were 84% and 88.5% when treated with EHC and EHR, respectively. The evaluation of cytotoxicity in HaCat showed that after treatments with different concentrations of extracts, cell viability remained above 70% in all groups. Therefore, it is concluded that EHC and EHR have important antioxidant and antibacterial action, both in planktonic cultures and in biofilms, and did not show cytotoxic effects in the tested concentration range. (AU)

Molecular analysis of the prevalence of Acinetobacter baumannii in hospitals and the surrounding environments: a cross-sectional study

Acinetobacter baumannii is widely recognized in clinical environments due to its infectious capacity, antimicrobial adaptability, and lethality. Analyzing the prevalence of this agent in intra- and extra-hospital environments may reveal target indicators for appropriate management interventions. In this observational cross-sectional study, we evaluated the prevalence of A. baumannii within hospitals with intensive care units and in their external surroundings in a macro-health region of Brazil. Samples of Columba livia (pigeon) droppings from the external environment of four hospitals (n = 40), from floor surfaces (n = 20), and door handles (n = 20) of different hospital wards were collected based on random sampling, all of which were evaluated for the presence of A. baumannii using polymerase chain reactions (PCR). The sensitivity and specificity of the technique was verified after the collected samples were contaminated with clinical samples positive for A. baumannii. We detected a significantly higher A. baumannii prevalence (87.50%, CI = 71.29­100.00) in samples collected within the hospital environment compared with those obtained from the external environment (12.50%, CI = 0.00­28. 71) (p = 0.003). In addition, samples collected from floor surfaces contained bacterial densities (181.3 ± 11.58) that exceeded those in environmental (93.32 ± 1.56) and door handle (142.70 ± 17.14) samples by 94% and 78.71%, respectively. The findings of this study will enhance our understanding of the spatial distribution of A. baumannii and additionally, validate the efficiency of PCR for diagnosis of this infectious agent.

Influencing factors of blood infection and death risk of Acinetobacter baumannii in elderly patients / 公共卫生与预防医学

Objective To investigate the death prognosis and risk factors of extensively drug-resistant Acinetobacter baumannii in hospitalized elderly patients with hematological infection, so as to facilitate clinical prevention and treatment. Methods The elderly (> 80 years old) hospitalized patients with hematological infection in our hospital from 2015 to 2021 were selected for analysis. Firstly, 314 patients with extensively drug-resistant Acinetobacter baumannii hematological infection were distinguished by etiological analysis. A total of 98 cases of death were detected during hospitalization (later referred to as the observation group). By comparing with the surviving patients (216 cases) (later referred to as the control group), the general data of patients with XDRAB infection were collected, and the risk of death and its influencing factors were analyzed. Results In the study, the proportion of patients in the observation group who used catheters was higher, the catheter retention time was longer, the acute physiology and chronic health status II scores were higher, and the proportion of patients who lost self-care ability was also higher. Conclusion The death of blood borne infection of extensively drug-resistant Acinetobacter baumannii in elderly patients is affected by many factors. Among them, patients who use catheters for a long time, have poor self-care ability and lose self-care ability have a higher risk of death, which is worthy of clinical attention.

Analysis of risk factors of multidrug-resistant organism infection in lung transplant recipients based on restricted cubic spline model / 器官移植

Objective To summarize current status of multidrug-resistant organism (MDRO) infection in lung transplant recipients and analyze the risk factors of MDRO infection. Methods Clinical data of 321 lung transplant recipients were retrospectively analyzed. According to the incidence of postoperative MDRO infection, they were divided into the MDRO group (n=122) and non-MDRO infection group (n=199). The incidence of MDRO infection in lung transplant recipients was summarized. The risk factors of MDRO infection in lung transplant recipients were analyzed by logistic regression model. The dose-response relationship between MDRO infection and time of ventilator use was determined by restricted cubic spline model. Results Among 321 lung transplant recipients, 122 cases developed MDRO infection, with an infection rate of 38.0%. Two hundred and twenty-nine strains of pathogenic bacteria were detected in the MDRO infection group, mainly Gram-negative bacteria (92.6%), and the top three strains were carbapenem-resistant acinetobacter baumannii (46.3%), carbapenem-resistant pseudomonas aeruginosa (22.3%) and carbapenem-resistant klebsiella pneumoniae (14.8%), respectively. MDRO infection mainly consisted of lower respiratory tract infection (61.5%), followed by ventilator-associated pneumonia (26.2%). Univariate analysis showed that the risk factors of MDRO infection in lung transplant recipients were single-lung transplantation, long-time postoperative use of extracorporeal membrane oxygenation (ECMO), long operation time, long-time urinary catheterization, long-time central venous catheterization and long-time ventilator use (all P < 0.05). Multivariate logistic regression analysis indicated that single-lung transplantation and long-time ventilator use were the independent risk factors for MDRO infection in lung transplant recipients (both P < 0.05). Results of restricted cubic spline model analysis showed that the risk of infection continued to increase with the prolongation of ventilator use time within 20 d. After 20 d, prolonging the time of ventilator use failed to increase the risk of infection, showing a plateau effect. Conclusions The MDRO infection rate tends to decline in lung transplant recipients year by year. Single-lung transplantation and long-time ventilator use are the independent risk factors for MDRO infection in lung transplant recipients.

Pathogenic mechanism of Acinetobacter baumannii and research status of corresponding vaccines / 中国生物制品学杂志

@#As a Gram-negative bacillus,Acinetobacter baumannii is one of the main opportunistic pathogens causing nosocomial infection,and mainly infects various human organs such as lungs,which finally causes bacteremia,pneumonia and other diseases,and seriously threatens lives of patients.People with weak immunity are the main susceptible people.The strain has strong stress resistance and multiple antibiotic resistance,making its infection a difficult problem in clinical treatment.The outer membrane complex(OMC),outer membrane vesicles(OMVs),secretory system and lipopolysaccharide of A.baumannii play an important role in the process of infection of host cells.At present,the vaccines developed against these pathogenic components can play a certain role in preventing and treating A.baumannii infection,and have a good application prospect.In this paper,the pathogenesis of A.baumannii and the current situation of vaccine development are reviewed,so as to provide a reference for the development of novel prevention and treatment methods of it in clinic.

Value of drug resistance and homology of Acinetobacter baumannii in tracing the source of nosocomial infection in Jianyang, Sichuan / 中国热带医学

@#Abstract: Objective　To analyze the drug sensitivity and the carrying of carbapenem resistant gene of Acinetobacter baumannii isolated from clinical patients and clinical objects, and analyze the homology of strains to provide support for the control of nosocomial infection. Methods　A total of 38 strains of Acinetobacter baumannii isolated from patients and clinical objects surface were collected from January 2019 to August 2020. The antimicrobial susceptibility was tested by the minimum inhibitory concentration method. In addition, the resistance related genes were detected by polymerase chain reaction method, and homology analysis was performed by enterobacterial repetitive Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR). Results All 34 strains of Acinetobacter baumannii isolated from Clinical patients and 4 strains isolated from clinical objects carried blaOXA-51 and imp resistance genes, neither of them carried blaVIM gene. 32 Acinetobacter baumannii carrying blaOXA-23 gene, 28 strains carrying blaTEM gene, 7 strains carrying blaOXA-58 gene. After cluster analysis, 38 Acinetobacter baumannii isolates were classified into 7 genotypes (expressed A, B, C, D, E, F, G), and cluster E and cluster G were the main clusters, containing 12 strains (12/38, 31.6%) and 18 strains (18/38, 47.4%), respectively, as the main prevalent clonal strains. Conclusions　Acinetobacter baumannii isolated from different sources have the significant differences in drug resistance and carry different resistance genes. There is no direct correlation between patients and environmental isolates of Acinetobacter baumannii belonging to different clonal strains. Also, there aren’t significant correlation between clinical patients infected with Acinetobacter baumannii.

Research progress of anti-Acinetobacter baumannii drug / 药学学报

Compared with other drug-resistant strains, Acinetobacter baumannii has the characteristics of serious drug resistance, high mortality and difficulty to treat. As the phenomena of resistance to existing anti-Acinetobacter baumannii drugs continuously occurs, the development of new anti-Acinetobacter baumannii drugs is urgent. This review introduces the clinical application and research progress of anti-Acinetobacter baumannii drugs, aiming to provide help for the research and development of anti-Acinetobacter baumannii drugs.

Preliminary study on high throughput screening small molecules targeting Gram-negative bacilli outer membrane protein BamA / 中华检验医学杂志

Objective:High-throughput screening to obtain small molecular compounds against Gram-negative bacilli by targeting BamA outer membrane protein.Methods:The sybyl-X2.1 software was used to perform high-throughput virtual screening of small molecular compounds in Chemdiv compound library based on the molecular docking. The top 150 hits by high-throughput screening were re-screened through in vitro biological experiments. The top 4 small molecules with obvious antibacterial activity were selected for in-depth molecular docking analysis, and the small molecule 8308-0401 with the highest docking score was selected for further experiments. The antibacterial effect of 8308-0401 combined with rifampicin was tested by checkerboard assay. Finally, the affinity between 8308-0401 and BamA was tested by plasma surface resonance assay. Results:The docking score of the top 150 hits calculated by high-throughput virtual screening had a mean value of 5.63. In vitro biological experiments showed that small molecules 8308-0401, 8365-1335, C066-2507 and L582-0346 exhibited strong antibacterial activity. Among those molecules, 8308-0401 showed the highest molecular docking score, and synergistic antibacterial activity against both types of strains and clinical isolates when combined with rifampicin. 8308-0401 has a strong affinity to BamA with binding a constant of 182 μmol/L. Conclusion:The small molecule 8308-0401 exerts antibacterial activity against Gram negative bacilli by targeting the outer membrane protein BamA.

Multi Drug Resistance and Multi Antibiotics Resistance Index of Acinetobacter baumannii Isolated from Hospitals in Port Harcourt Metropolis

Acinetobacter species are aerobic gram-negative bacilli that can cause healthcare-associated infections and can survive for prolonged periods in the environment. Also on the hands of healthcare workers, infection due to Acinetobacter species is a major challenge within the health care facilities and the community in general due to their high drug resistance. The study was aimed at detecting multi drug resistance and multi antibiotics resistance index (MARI) of acinetobacter baumannii isolated from hospitals in Port Harcourt meteropolis in Rivers State, Nigeria. The cross sectional study sampled randomly; as urine and wound swab samples were collected from patients. Acinetobacter spp was isolated using standard microbiological methods. Identification of A. baumannii isolates were done using Phynotypic methods such as culture on Lead Acinetobacter medium and conventional biochemical tests. Antimicrobial susceptibility test was done by Kirby Bauer’s disk diffusion method under Clinical Laboratory Standards Institute (CLSI, 2013) guide Suspect Acinetobacter species were further identified using polymerase chain reaction (PCR) and Sanger sequence typing methods. The results of confirmatory sequence typing of isolates showed that 9 of suspect Acinetobacter spp were A. baumannii. The results of this finding showed presence of A. baumannii species resistant to conventional antibiotics. All isolates demonstrated.MDR and XDR. MARI was high. (>0.2) indicating MDR and high risk. This study established high rate of multidrug resistant Acinetobacter baumanii. There is need for improved sanitary working condition and proper patients’ management to reduce the spread of this health care associated infection as well as a Search for new therapeutic alternative and policies to control the use of antibiotics.

Capacidade de formação de biofilmes e perfil de resistência de Acinetobacter baumannii isolados em unidades de terapia intensiva: uma revisão sistemática

Introdução: Acinetobacter baumanni é um cocobacilo Gram negativo responsável por elevadas taxas de infecções relacionadas à assistência à saúde (IRAS). Apresenta alto nível de resistência intrínseca a antimicrobianos, além da capacidade de adquirir resistência a carbapenêmicos e polimixinas. Ainda, A. baumannii possui habilidade para produzir biofilmes em superfícies abióticas e bióticas, o que favorece a infecção de pacientes gravemente enfermos internados em unidades de terapia intensiva (UTI). Deve ser ressaltado que bactérias envolvidas em biofilmes apresentam maior resistência aos antimicrobianos, atribuída a fatores bioqúmicos, moleculares e as condições dos hospedeiros, o que dificulta o tratamento dessas infecções. Objetivos: Avaliar a produção de biofilme por isolados de A. baumannii recuperados de pacientes internados em UTIs, bem como operfil de susceptibilidade a antimicrobianos (aminoglicosídeos, tigeciclina, carbapenêmicos e polimixinas) entre esses isolados. Métodos: Foi realizada uma revisão sistemática de acordo com os critérios Prisma nos bancos de dados Pubmed/Medline, Scopus, Lilacs, Scielo, e Web of Science. Resultados: Foram incluídos um total de 12 artigos que avaliaram 1006 isolados clínicos de A. baumannii, os quais todos foram resistentes aos carbapenê-micos. No entanto, a maioria dos isolados permaneceu sensível as polimixinas B e E(94,46%). A porcentagem dos isolados produtores de biofilme foi alta (96,3%), e neste estudo não fica clara a relação entre a habilidade de produzir biofilmes e a resistência aos antimicrobianos analisados. Conclusão: Mais estudos devem ser conduzidos para monitorar a resistência aos antimicrobianos em A. baumannii, sobretudo em produtores de biofilme, visto que o manejo terapêutico das infecções ocasionadas por essas linhagens torna-se mais complexo e desafiador.

SUMMARY Introduction: Acinetobacter baumanni is a Gram-negative coccobacillus responsible for high rates of healthcare-related infections (HAI). It has a high level of intrinsic resistance to antimicrobials, in addition to the ability to acquire resistance to carbapenems and polymyxins. Furthermore, A. baumannii has the ability to produce biofilms on abiotic and biotic surfaces, which favors the infection of critically ill patients admitted to intensive care units (ICU). It should be noted that bacteria involved in biofilms have greater resistance to antimicrobials, attributed to biochemical and molecular factors and the conditions of the hosts, which makes the treatment of these infections difficult. Objectives: To evaluate the biofilm production by A. baumannii isolates recovered from ICU patients, as well as the antimicrobial susceptibility profile (aminoglycosides, tigecycline, carbapenems and polymyxins) among these isolates. Methods: A systematic review was performed according to PRISMA criteria in the PUBMED/MEDLINE, Scopus, LILACS, SciELO, and Web of Science databases. Results: A total of 12 articles that evaluated 1006 clinical isolates of A. baumannii, all of which were resistant to carbapenems, were included. However, most isolates remained sensitive to polymyxins B and E (94.46%). The percentage of biofilm-producing isolates was high (96.3%), and in this study the relationship between the ability to produce biofilms and resistance to the analyzed antimicrobials is not clear. Conclusion: More studies should be conducted to monitor antimicrobial resistance in A. baumannii, especially in biofilm producers, as the therapeutic management of infections caused by these strains becomes more complex and challenging.

Introducción: Acinetobacter baumanni es un cocobacilo gramnegativo responsable de altas tasas de infecciones relacionadas con la salud. Tiene un alto nivel de resistencia intrínseca a los antimicrobianos, además de la capacidad de adquirir resistencia a los carbapenémicos y polimixinas. Además, A. baumannii tiene la capacidad de producir biopelículas en superficies abióticas y bióticas, lo que favorece la infección de pacientes críticos ingresados en unidades de cuidados intensivos (UCI). Cabe señalar que las bacterias involucradas en biofilms tienen mayor resistencia a los antimicrobianos, atribuida a factores bioquímicos y moleculares y a las condiciones de los hospedadores, lo que dificulta el tratamiento de estas infecciones. Objetivos: Evaluar la producción de biofilm por aislamientos de A. baumannii recuperados de pacientes de UCI, así como el perfil de susceptibilidad antimicrobiana (amino-glucósidos, tigeciclina, carbapenémicos y polimixinas) entre estos aislamientos. Métodos: Se realizó una revisión sistemática según los criterios Prisma en las bases de datos Pubmed / Medline, Scopus, Lilacs, SciELO y Web of Science. Resultados: Se incluyeron un total de 12 artículos que evaluaron 1006 aislamientos clínicos de A. baumannii, todos ellos resistentes a carbapenémicos. Sin embargo, la mayoría de los aislados permanecieron sensibles a las polimixinas B y E (94,46%). El porcentaje de aislamientos productores de biopelículas fue alto (96,3%), y en este estudio no está clara la relación entre la capacidad de producir biopelículas y la resistencia a los antimicrobianos analizados. Conclusión: Se deben realizar más estudios para monitorear la resistencia a los antimicrobianos en A. baumannii, especialmente en productores de biopelículas, ya que el manejo terapéutico de las infecciones causadas por estas cepas se vuelve más complejo y desafiante.

Mechanisms involved in resistance to carbapenems among Acinetobacter baumannii isolates recovered in Brazil: A systematic review and meta-analysis

SUMMARY Introduction: Infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) is a health problem due to the limited therapeutic options available. This study was carried out to evaluate the main mechanisms of resistance of carbapenems in CRAB in the last 10 years in Brazil and to describe the susceptibility profile to tigecycline and polymyxins in these isolates. Material and methods: A systematic review was carried out according to Prisma in PUBMED/MEDLINE, Scopus, SciELO, Biblioteca Virtual de Saúde (BVS) and Cochrane Library. Data regarding enzyme resistance to carbapenems were evaluated by meta-analysis according to the random effect. Results: 21 articles were selected according to inclusion and exclusion criteria that evaluated 1096 CRAB. Most of the studies were carried out in the southern (33.3 %) and southeast (23.8 %) regions of Brazil (33.3 %) and in 2016 and 2018. According to the meta-analyzes, OXA-type carbapenemase was the main mechanism involved in the low susceptibility to carbapenems in CRAB (98%; 95% CI: 0.91, 0.99; I2 = 95%), with bla OXA-23-like (91 %; 95 % CI: 0.76; 0.97; I2 = 97 %) or bla OXA-51-like / ISAba1 (84 %; 95 % CI: 0.15, 0.99; I2 = 98 %) genes, followed by metallo-ß-lactamases (MBL) (12 %, 95 % CI: 0.09, 0.15, I2 = 99 %) and Klebsiella pneumoniae carbapenemase (KPC) (6 %, 95 % CI: 0.04; 0.08; I2 = 87 %). Conclusion: The included studies showed that susceptibility to colistin (99 %) and tigecy-cline (93 %) remains high and was not affected by carbapenem resistance.

Introducción: Las infecciones por Acinetobacter baumannii resistente a carbapenémicos (CRAB) es un problema de salud debido a las limitadas opciones terapéuticas disponibles. Este estudio se realizó para evaluar los principales mecanismos de resistencia de los carbapenémicos en CRAB en los últimos 10 años en Brasil y describir el perfil de susceptibilidad a tigeciclina y polimixinas en estos aislados. Material y métodos: Se realizó una revisión sistemática de acuerdo con Prisma en PUBMED/MEDLINE, Scopus, SciELO, Biblioteca Virtual de Saúde (BVS) y Cochrane Library. Los datos referentes a resistencia enzimática a los carbapenémicos se evaluaron mediante metaanálisis según el efecto aleatorio. Resultados: Se seleccionaron 21 artículos según criterios de inclusión y exclusión que evaluaron 1.096 CRAB. La mayoría de los estudios se llevaron a cabo en las regiones sur (33,3%) y sureste (23,8 %) de Brasil (33,3 %) y en los años 2016 y 2018. Según los metaanálisis, la carbapenemasa tipo OXA fue el principal mecanismo implicado en la baja susceptibilidad a los carbapenémicos en CRAB (98 %; IC 95 %: 0,91; 0,99; I² = 95 %), con bla OXA-23-like (91 %; 95 % CI: 0,76; 0,97; I² = 97 %) o bla OXA-51-like / ISAba1 (84 %; 95 % CI: 0,15; 0,99 ; I² = 98 %) genes, seguida de metalo-ß-lactamasas (MBL ) (12 %; IC95 %: 0,09; 0,15; I² = 99 %) y Klebsiella pneumoniae carbapenemase (KPC) (6 %; IC95 %: 0,04; 0,08; I² = 87 %). Conclusión: Los estudios incluidos mostraron que la susceptibilidad a la colistina (99 %) y tigeciclina (93 %) sigue siendo alta y no se ve afectada por la resistencia a los carbapenémicos.

Introdução: As infecções causadas por Acinetobacter baumannii resistente aos carbapenémicos (CRAB) são um problema de saúde devido às limitadas opções terapêuticas disponíveis. Este estudo foi realizado para avaliar os principais mecanismos de resistência aos carbapenêmicos em CRAB nos últimos 10 anos no Brasil e descrever o perfil de susceptibilidade à tigeciclina e às polimixinas nesses isolados. Material e métodos: Foi conduzida uma revisão sistemática segundo o Prisma nas bases de dados PUBMED/MEDLINE, Scopus, SciELO, Biblioteca Virtual de Saúde (BVS) e Biblioteca Cochrane. Os dados relativos à resistência enzimática aos carbapenêmicos foram avaliados por meta-análises de acordo com o efeito aleatório. Resultados: Foram selecionados 21 artigos de acordo com os critérios de inclusão e exclusão que avaliaram 1.096 CRAB. A maioria dos estudos foi realizada nas regiões Sul (33,3 %) e Sudeste (23,8 %) do Brasil e nos anos de 2016 e 2018. De acordo com as metanálises, a carbapenemase do tipo OXA foi o principal mecanismo envolvido na baixa susceptibilidade aos carbapenêmicos em CRAB (98 %; 95% IC: 0.91, 0.99; I² = 95 %), com bla OXA-23-like (91 %; 95 %; IC: 0,76; 0,97; I² = 97 %) ou bla OXA -51-like / ISAba1 (84 %; 95 % IC: 0.15, 0.99; I² = 98 %) genes, seguidos por metalo-ß-lactamases (MBL) (12 %, 95 % IC: 0,09, 0,15, I² = 99 %) e Klebsiella pneumoniae carbapenemase (KPC) (6 %, IC 95 %: 0,04; 0,08; I² = 87 %). Conclusão: Os estudos incluídos mostraram que a susceptibilidade à colistina (99 %) e tigeciclina (93 %) permanece alta e não foi afetada pela resistência aos carbapenêmicos.

Caracterización de especies de Acinetobacter causantes de infecciones en hospitales cubanos / Characterization of Acinetobacter species, contributors to infections in Cuban hospitals

Introducción: Acinetobacter spp. constituye un patógeno relevante en Cuba. El complejo Acinetobacter baumannii-calcoaceticus es la principal especie causante de infecciones graves. Se aísla frecuentemente en las unidades de cuidados intensivos (UCI) y exhibe una elevada resistencia a la mayoría de los antibióticos disponibles, incluidos los carbapenémicos. Objetivo: Caracterizar los aislados de Acinetobacter obtenidos de pacientes ingresados en hospitales cubanos. Métodos: Se realizó un estudio retrospectivo en el Laboratorio de Infecciones Asociadas a la Asistencia Sanitaria del Instituto de Medicina Tropical Pedro Kourí, que incluyó 278 aislados conservados durante junio de 2011 a julio de 2012, pertenecientes a la colección de cultivos del laboratorio y procedentes de 21 hospitales, distribuidos en nueve provincias. Las especies se identificaron mediante pruebas bioquímicas y se determinó la susceptibilidad a 18 antibióticos por el método de Bauer-Kirby, excepto la colistina, cuya determinación se realizó por el E-test (método epsilométrico). Las variables analizadas fueron: especie de Acinetobacter, tipo de muestra, tipo de servicio hospitalario, susceptibilidad a los antimicrobianos y categorización de la multirresistencia a los antimicrobianos. Resultados: Predominó el complejo Acinetobacter baumannii-calcoaceticus, fundamentalmente en muestras de secreción endotraqueal y sangre. Las UCI y unidades de quemados fueron los servicios hospitalarios más afectados. Se detectaron porcentajes elevados de resistencia para los betalactámicos (76-94 por ciento), aminoglucósidos (66-80 por ciento) y fluoroquinolonas (60-89 por ciento). La tetraciclina, doxiciclina y colistina resultaron los antimicrobianos más activos. El 73,5 por ciento de los aislados fueron multidrogorresistentes, el 26,1 por ciento extremodrogorresistentes y un aislado resultó pandrogorresistente (0,4 por ciento). Conclusiones: Las infecciones provocadas por Acinetobacter spp. constituyen un grave problema de salud en los hospitales cubanos. Los aislados se caracterizaron por una elevada resistencia a los antibióticos disponibles y revelan la necesidad del monitoreo continuo de la susceptibilidad a los antimicrobianos, además del reforzamiento de las medidas de control, principalmente en las UCI(AU)

Introduction: Acinetobacter spp. is a relevant pathogen in Cuba. The Acinetobacter baumannii-calcoaceticus complex is the main cause of severe infections. It is frequently isolated in intensive care units (ICU) and exhibits high resistance to most available antibiotics, including carbapenems. Objective: To characterize the Acinetobacter isolates collected from patients admitted to Cuban hospitals. Methods: A retrospective study was conducted at the Healthcare-Associated Infections Laboratory of "Pedro Kourí" Tropical Medicine Institute. The study included 278 isolates from 21 hospitals located in 9 provinces, stored from June 2011 to July 2012 in the culture collection of the laboratory. Species identification was based on biochemical tests and the susceptibility to 18 antibiotics was determined by the Bauer-Kirby method, except for colistin, for which the E-test (epsilometric method) was used. The variables under analysis were: Acinetobacter species, type of sample, type of healthcare service, antimicrobial susceptibility, and antimicrobial multi-resistance categorization. Results: Acinetobacter baumannii-calcoaceticus complex prevailed, mainly in endotracheal fluid and blood samples. The ICU and the burn unit were the most affected healthcare services. High resistance percentages were observed to beta-lactams (76-94%), aminoglycosides (66-80%), and fluoroquinolones (60-89%). Tetracycline, doxycycline, and colistin were the most active antimicrobials. Multi-drug-resistance was observed in 73.5% of isolates, extensively-drug-resistance in 26.1%, and pan-drug-resistance in one isolate (0.4%). Conclusions: Infections by Acinetobacter spp. constitute a serious health problem in the Cuban hospitals. High resistance to available antibiotics characterizes the isolates, which evidences the need to constantly monitor antimicrobial susceptibility and to reinforce the control measures, mainly in the ICUs.

Mecanismo de resistência da bactéria Acinetobacter Baumannii e suas implicações no controle das infecções hospitalares / Mechanism of resistance of Acinetobacter Baumannii bacteria and its implications in control of hospital infections

O gênero Acinetobacter spp. surgiu como patógeno hospitalar oportunista, com numerosos surtos hospitalares. O gênero Acinetobacter spp. compreende até 31 espécies, entre elas a espécie Acinetobacter baumannii que é responsável por cerca de 80% das infecções, as quais podem se espalhar de forma epidêmica entre os pacientes hospitalizados e gravemente doentes. A espécie A. baumannii pode estar presente no ambiente hospitalar em máquinas de diálise; nos ventiladores mecânicos; nos monitores de pressão arterial; nos sistemas de ventilação; nas fontes de água; na pele e mucosas dos profissionais de saúde e dos doentes; nas preparações medicamentosas e até nos desinfetantes. Uma ampla variedade de objetos de uso do paciente, como cama, travesseiro, aparelho de televisão e de som, tem sido encontrada contaminada com Acinetobacter, podendo servir como reservatórios durante um surto nosocomial. Para manter resistência, a bactéria deve sofrer alteração no seu material genético, o que poderá ocorrer de duas formas: indução de mutação no DNA ou processo de transformação. Os principais mecanismos de resistência são a alteração da permeabilidade, alteração do sítio de ação do antimicrobiano, bomba de efluxo e mecanismo enzimático pela produção de beta-lactmases, sendo que os principais processos ocorrem por meio de conjugação, transformação e transdução.

The genus Acinetobacter spp emerged as an opportunistic hospital pathogen, with numerous hospital outbreaks. The genus Acinetobacter spp. comprises up to 31 species, among them the species Acinetobacter baumannii is responsible for about 80% of infections which can spread epidemically among hospitalized and seriously ill patients. A. baumannii may be present in the hospital environment on dialysis machines; mechanical fans; blood pressure monitors; ventilation systems; in water sources; on the skin and mucous membranes of health professionals and patients; in drug preparations and even disinfectants. A wide variety of objects for use by the patient, such as bed, pillow, television and stereo, have been found contaminated with Acinetobacter and can serve as reservoirs during a nosocomial outbreak. To maintain resistance, the bacterium must undergo changes in its genetic material, which may occur in two ways: mutation induction in DNA or transformation process. The main resistance mechanisms are the change in permeability, alteration of the antimicrobial action site, efflux pump and enzymatic mechanism by the production of ß-lactmases, and the main processes occur through conjugation, transformation and transduction.

Effects of tigacycline-based combination therapy onprocalcitonin, high sensitivity C-reactive protein and interleukin-6 in patients with multiple drug-resistant acinetobacterbaumannii post-operative abdominal infection in intensive care unit / 中国医师进修杂志

Objective:To explore the effects of tigacycline-based combination therapy on procalcitonin (PCT), high sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) in patients with multiple drug-resistant acinetobacterbaumannii post-operative abdominal infection in intensive care unit (ICU).Methods:Seventy-five patients with multiple drug-resistant acinetobacter baumannii post-operative abdominal infection in ICU admitted to West Central Hospital of Hainan Prorvincefrom October 2015 to October 2018 were selected and divided into the control group (37cases) and the observation group (38 cases) according to random number table method. The control group was treated with cefoperazone-sulbactam on the basis of routine treatment, while the observation group was treated with tegacycline on the basis of the control group. Both groups were treated for 1 week. The clearance of acinetobacterbaumannii and clinical efficacy of the two groups were counted; the levels of serum PCT, hs-CRP and IL-6 and ummune function were compared.Results:The clearance rate of acinetobacterbaumannii in the observation group was significantly higher than that in the control group: 76.32%(29/38) vs. 54.05%(20/37), χ2 = 4.10, P = 0.043. Compared with before treatment, the levels of serum PCT, hs-CRP and IL-6 in the two groups were decreased after 1 week of treatment, and the levels of serum PCT, hs-CRP and IL-6 in the observation group were lower than those in the control group ( P<0.05). Compared with before treatment, the levels of peripheral blood CD 3+, CD 4+, CD 4+/CD 8+ were increased and peripheral blood CD 8+ was decreased in both groups, and the levels of peripheral blood CD 3+, CD 4+, CD 4+/CD 8+ in the observation group were higher than those in the control group ( P<0.05), while the level of peripheral blood CD 8+ in the observation group was lower than that in the control group ( P<0.05). The total effective rate in the observation group was significantly higher than that in the control group: 89.47% (34/38) vs. 67.57% (25/37), χ2 = 4.13, P<0.05. Conclusions:Tigacycline combined with cefoperazone-sulbactam in the treatment of intra-abdominal infection after surgery of acinetobacterbaumannii in ICU could reduce the levels of serum PCT, hs-CRP, IL-6, reduce the body′s inflammatory response and improve the immune function, and improve the treatment efficiency of intra-abdominal infection.