Antimicrobial resistance in Enterobacteriaceae in Brazil: focus on ß-lactams and polymyxins

ABSTRACT During the last 30 years there has been a dissemination of plasmid-mediated β-lactamases in Enterobacteriaceae in Brazil. Extended spectrum β-lactamases (ESBL) are widely disseminated in the hospital setting and are detected in a lower frequency in the community setting. Cefotaximases are the most frequently detected ESBL type and Klebsiella pneumoniae is the predominant species among ESBL producers. Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae became widely disseminated in Brazil during the last decade and KPC production is currently the most frequent resistance mechanism (96.2%) in carbapenem resistant K. pneumoniae. To date KPC-2 is the only variant reported in Brazil. Polymyxin B resistance in KPC-2-producing K. pneumoniae has come to an alarming rate of 27.1% in 2015 in São Paulo, the largest city in Brazil. New Delhi metallo-β-lactamase was detected in Brazil in 2013, has been reported in different Brazilian states but are not widely disseminated. Antimicrobial resistance in Enterobacteriaceae in Brazil is a very serious problem that needs urgent actions which includes both more strict adherence to infection control measures and more judicious use of antimicrobials.

Efficacy of polymyxins in the treatment of carbapenem-resistant Enterobacteriaceae infections: a systematic review and meta-analysis

In recent years, carbapenem-resistant Enterobacteriaceae has become endemic in many countries. Because of limited treatment options, the abandoned "old antibiotics", polymyxins, have been reintroduced to the clinic. To evaluate the clinical efficacy of polymyxins in the treatment of infections caused by carbapenem-resistant Enterobacteriaceae, we systemically searched the PubMed, Embase, and Cochrane Library databases and analyzed the available evidence. The Preferred Reporting Items for Systematic reviews and Meta-Analysis statement were followed, and the I2 method was used for heterogeneity. Nineteen controlled and six single-arm cohort studies comprising 1086 patients met the inclusion criteria. For controlled studies, no significant difference was noted for overall mortality (OR, 0.79; 95% CI, 0.58-1.08; p = 0.15), clinical response rate (OR, 1.24; 95% CI, 0.61-2.54; p = 0.55), or microbiolog- ical response rate (OR, 0.59; 95% CI, 0.26-1.36; p = 0.22) between polymyxin-treated groups and the control groups. Subgroup analyses showed that 28-day or 30-day mortality was lower in patients who received polymyxin combination therapy than in those who received monotherapy (OR, 0.36; 95% CI, 0.19-0.68; p < 0.01) and the control groups (OR, 0.49; 95% CI, 0.31-0.75; p < 0.01). The results of the six single-arm studies were in accordance with the findings of controlled studies. One controlled and two single-arm studies that evaluated the occurrence of nephrotoxicity reported a pooled incidence rate of 19.2%. Our results suggest that polymyxins may be as efficacious as other antimicrobial therapies for the treatment of carbapenem-resistant Enterobacteriaceae infection. Compared to polymyxin monotherapy, combination regimens may achieve lower 28-day or 30-day mortality. Future large-volume, well-designed randomized control trials are required to determine the role of polymyxins in treating carbapenem-resistant Enterobacteriaceae infections.

Eficacia, tolerancia y seguridad de una combinación de metronidazol, miconazol, centella asiática, polimixina y neomicina en cápsula blanda para uso vaginal en el tratamiento de la vaginosis bacteriana / Efficacy, tolerability, and safety of a combination including metronidazole, miconazole, Gotu kola, polymixin, and neomycin in soft vaginal capsules for the treatment of bacterial vaginosis

Introducción: La vaginosis bacteriana (VB) es un síndrome polimicrobiano, en la cual la flora dominante de lactobacilos normales es sustituida por una flora polimicrobiana. La prevalencia de VB en Perú varía entre 27 y 43,7%. El Centro de Control y Prevención de Enfermedades (DCD) sugiere el tratamiento de VB en mujeres sintomáticas con metronidazol oral/gel o clindamicina crema. Se planteó en el presente estudio evaluar la eficacia, tolerancia y seguridad de la combinación de metronidazol, miconazol, centella asiática, polimixina y neomicina en cápsula blanda para el tratamiento de VB. Material y Métodos: El presente estudio de tipo abierto, observacional, prospectivo, permitió evaluar la eficacia, tolerancia y seguridad en la aplicación de la combinación de metronidazol, miconazol, centella asiática, polimixina y neomicina en cápsula blanda. Resultados: Se incluyó a 61 pacientes con edad promedio de 29.28 años (rango 18-48) de las cuales 93,4% tenía historia previa de flujo vaginal anormal. Se realizaron dos visitas durante el estudio, la primera para diagnóstico e inicio de tratamiento y la segunda de control post tratamiento. Tres pacientes no tuvieron segunda visita y 8 no tenían registrada toda la información para definir la respuesta terapéutica. La segunda visita se realizó a los 21 días en promedio. Los principales signos y síntomas en la primera visita de diagnóstico fueron flujo vaginal (100,0%), disconfort vaginal (85,2%), dispareunia (70,5%) y dolor abdominal bajo (57,4%), las cuales disminuyeron en forma significativa (p<0,05) a la segunda visita post tratamiento. La prueba de aminas resultó positiva en el 93,4% de los casos en la primera visita y en el 15,5% de los casos en la segunda visita (p<0,05). De la población inicial de estudio, solo 53 mujeres son evaluables para eficacia terapéutica...

Introduction: Bacterial vaginosis (BV) is a polymicrobial syndrome, in which the normal dominant flora consisting in Lactobacillus is replaced by polymicrobial flora. The prevalence of BV in Peru varies between 27 and 43.7%. The Centers for Disease Control and Prevention suggest therapy for BV in symptomatic women should include oral/gel metronidazole or clindamycin cream. We proposed in this study to evaluate the efficacy, tolerability and safety of the combination of metronidazole, miconazole, Gotu kola (Centella asiatica), polymixin, and neomycin in soft capsules, for the treatment of BV. Material and Methods: This investigation was an open, observational, and prospective study, which allowed us to evaluate the efficacy, tolerability and safety of the aforementioned combined therapy administered in soft capsules. Results: The study included 61 patients with a mean age of 29.28 years (range, 18-48) and 93.4% had a history of abnormal vaginal discharge. Two visits took place during the study, the first for making the diagnosis and initiating therapy, and the second was the post-treatment control. Three patients did not have a second visit and 8 did not record all the information required to define the therapeutic response. The second visit took place after 21 days on average. The main signs and symptoms at the first visit were vaginal discharge at diagnosis (100.0%), vaginal discomfort (85.2%), dyspareunia (70.5%) and lower abdominal pain (57.4%), which were significantly reduced (p <0.05) in the second visit after treatment. The amine test was positive in 93.4% of cases in the first visit and in 15.5% of cases in the second visit (p <0.05). From the initial population in the study, only 53 women are evaluable for efficacy. An overall response rate in 44 women (83.02%) was achieved with the soft capsule combination treatment. Adverse events were reported in only one case...

Polymyxins: Antimicrobial susceptibility concerns and therapeutic options.

The increasing prevalence of multidrug-resistant nosocomial pathogens such as Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae poses a great challenge to the treating physicians. The paucity of newer effective antimicrobials has led to renewed interest in the polymyxin group of drugs, as a last resort for treatment of gram-negative bacterial infections. There is a dearth of information on the pharmacological properties of colistin, leading to difficulties in selecting the right dose, dosing interval, and route of administration for treatment, especially in critically-ill patients. The increasing use of colistin over the last few years necessitates the need for accurate and reliable in vitro susceptibility testing methods. Development of heteroresistant strains as a result of colistin monotherapy is also a growing concern. There is a compelling need from the clinicians to provide options for probable and possible colistin combination therapy for multidrug-resistant bacterial infections in the ICU setting. Newer combination drug synergy determination tests are being developed and reported. There are no standardized recommendations from antimicrobial susceptibility testing reference agencies for the testing and interpretation of these drug combinations. Comparison and analysis of these reported methodologies may help to understand and assist the microbiologist to choose the best method that produces accurate results at the earliest. This will help clinicians to select the appropriate combination therapy. In this era of multidrug resistance it is important for the microbiology laboratory to be prepared, by default, to provide timely synergistic susceptibility results in addition to routine susceptibility, if warranted. Not as a favour or at request, but as a responsibility.

A randomized double-blind clinical trial of the effect of non-absorbable oral polymyxin on infants with severe infectious diarrhea

The present study evaluated the effect of non-absorbable oral polymyxin on the duodenal microflora and clinical outcome of infants with severe infectious diarrhea. Polymyxin was chosen because classic enteropathogenic Escherichia coli was more sensitive to this antibiotic. Twenty-five infants were randomly assigned to a 7-day treatment with oral polymyxin (2.5 mg/kg in 4 daily doses) or placebo. Duodenal and stool cultures were performed before and after the treatment. Five patients were excluded during the study because of introduction of parental antibiotic therapy due to clinical sepsis (N = 3) or rapid clinical improvement (N = 2). In the polymyxin group, small bowel bacterial overgrowth occurred in 61.5 percent of the cases (8/13) before treatment and in 76.9 percent (10/13) after treatment. In the placebo group these values were 71.4 percent (5/7) and 57.1 percent (4/7), respectively. By the 7th day, clinical cure was observed in 84.6 percent of the cases (11/13) in the polymyxin group and in 71.4 percent (5/7) in the placebo group (P = 0.587). Considering all 25 patients included in the study, clinical cure occurred on the 7th day in 12/14 cases (85.7 percent) in the polymyxin group and 6/11 cases (54.5 percent) in the placebo group (P = 0.102). Clinical sepsis occurred in 3/11 (27.3 percent) of the patients in the placebo group and in none (0/14) in the polymyxin group (P = 0.071). Oral polymyxin was not effective in reducing bacterial overgrowth or in improving the clinical outcome of infants hospitalized with severe infectious diarrhea. Taking into account the small sample size, the rate of cure on the 7th day and the rate of clinical sepsis, further studies with greater number of patients are necessary to evaluate these questions.

A cólera no Estado do Rio Grande do Norte--Brasil--perfil sorológico e de sensibilidade do Vibrio cholerae a diferentes antimicrobianos / Cholera in Rio Grande do Norte State--Brazil: sorology and sensitivity of Vibrio cholerae to different antimicrobials

PURPOSE: The emergence of multiple resistance to antimicrobials in Vibrio cholerae isolated in the state of Ceará, Brazil, alerted researchers in this area to the sensitivity to antimicrobials of strains isolated in Rio Grande do Norte (RN), Brazil. METHODS: One hundred and four strains of V. cholerae of human origin, isolated by Laboratório Central de Saúde Pública Dr. Almino Fernandes, were serologically typified and evaluated for in vitro sensitivity to eight antibiotics belonging to different groups (polymyxine, tetracycline, chloramphenicol, nitrofurantoin, sulphazotrin, pefloxacine, erythromycine, ampicillin). The strains were collected from patients suspected of contracting choleric diarrhea in the year 1999, in Natal/RN/Brazil. RESULTS: From the sample total, 100 were identified as V. cholerae, serogroup O:1, biotype El Tor, with 99 (95.3%) belonging to serovar Ogawa and only 1 (0.9%) to serovar Inaba. The 4 remaining were characterized as non O:1 V. cholerae, with 3 (2.9%) biochemically identified as Heiberg type I and 1 (0.9%) as type II. All the V. cholerae serogroup O:1 strains were sensitive to tetracycline, chloramphenicol, sulphazotrin, pefloxacine, erythromycine and resistant to polymyxine. In relation to nitrofurantoin, only 1 was sensitive. Only 1 was resistant to ampicillin. The non O:1 V. cholerae strains were resistant to polymyxine. CONCLUSIONS: The results showed sensitivity in 100% of the V. cholerae serogroup O:1 strains to tetracycline, an elective drug in the treatment of cholera, and an absence of multiple resistant strains in our environment. An interesting finding was the frequency of serovar Ogawa in 1999, considering the greater incidence of serovar Inaba in other years of cholera outbreaks in RN.

Tratamiento atópico en otitis media crónica / Topical treatment in chronic otitis media

Objetivo: Evaluar la respuesta al tratamiento tópico con ciprofloxacina comparado con neomicina-polimixina -fluocinolona (NPF) en la otitis media crónica supurada (OMCs). Material y Métodos: Se realizó un ensayo clínico aleatorio de 36 pacientes (40 oídos), con OMCs, en dos grupos de 20 oídos, uno tratado con ciprofloxacina y el otro con NPF. Se aplicó tratamiento durante 10 días, registrando la respuesta como buena, regular o mala. Resultados: 36 pacientes, 21 mujeres (53 por ciento) y 19 hombres /47 por ciento), entre 15 y 71 años (media 38 de +- 18.5), en la bacteriología predominaron Staphylococcus aureus y Pseudomonas sp. La respuesta al 10§ día con ciprofloxacina fue buena en 17 (85 por ciento), regular en 1 (5 por ciento) y mala en 2 (10 por ciento). Con NPF fue buena en 16 (80 por ciento), regular en 3 (15 por ciento) y mala en 1 (5 por ciento). Las diferencias no fueron estadísticamente significantes. Conclusiones: La ciprofloxacina y la NPF son igualmente efectivos en el control de la otitis media crónica supurada.

Avaliacao pre-operatoria na cirurgia da otite media cronica / Chronic suppurative otitis media: preoperative evaluation

A otite media cronica supurativa (OMCSup), infeccao do ouvido medio acompanhada de perfuracao timpanica e otorreia ou suas sequelas, e enfermidade frequente, particularmente na populacao mais carente, na qual o tratamento clinico primario pode ser deficiente. Diversas bacterias aerobias e anaerobias participam da infeccao do ouvido medio, principalmente Pseudomonas aeruginosa, Staphylococcus aureus e Bacterioides fragilis. Na OMCSup ativa (com otorreia), nosso tratamento inicial envolve limpeza metodica do conduto auditivo e a associacao de sulfametoxazol 800 mg+ trimetropin 160 mg po bid l4d com gotas otologicas de cloranfenicol e polimixina B. Embora empirica, essa terapeutica permite, com baixo custo, atacar os principais microrganismos, com risco inexpressivo de ototoxicidade. Cultura e antibiogramas da secrecao sao feitos apenas na falencia dessa medicacao, quando a escolha do antibiotico e baseada na bacteria (aerobia) isolada, adicionando-se metronidazol 400 mg po tid l4d, para combater presumiveis anaerobios associados. Apos, o paciente e avaliado quanto a sequelas e necessidade de tratamento cirurgico visando: 1) combater a infeccao e suas recrudescencias; 2) restaurar ou manter a audicao. Rotineiramente, sao feitos testes audiologicos e radiografias de ouvido nas posicoes de Schuller, Stenvers ou Guillen, e transorbitaria antero-posterior. Em casos especiais, podem ser necessarias tomografias lineares, e mesmo computadorizadas axiais-coronais de ouvidos, com janela ossea e para partes moles.