Efficacy of Tamoxifen Metabolites in Combination with Colistin and Tigecycline in Experimental Murine Models of Escherichia coli and Acinetobacter baumannii.

This study aimed to evaluate the potential of tamoxifen and N-desmethyltamoxifen metabolites as therapeutic agents against multidrug-resistant Escherichia coli and Acinetobacter baumannii, using a repurposing approach to shorten the time required to obtain a new effective treatment against multidrug-resistant bacterial infections. Characterisation and virulence studies were conducted on E. coli (colistin-susceptible C1-7-LE and colistin-resistant MCR-1+) and A. baumannii (tigecycline-susceptible Ab#9 and tigecycline-resistant Ab#186) strains. The efficacy of the metabolite mix (33.3% each) and N-desmethyltamoxifen in combination with colistimethate sodium (CMS) or tigecycline was evaluated in experimental models in mice. In the pneumonia model, N-desmethyltamoxifen exhibited significant efficacy against Ab#9 and both E. coli strains, especially E. coli MCR-1+ (-2.86 log10 CFU/g lungs, -5.88 log10 CFU/mL blood, and -50% mortality), and against the Ab#186 strain when combined with CMS (-2.27 log10 CFU/g lungs, -2.73 log10 CFU/mL blood, and -40% mortality) or tigecycline (-3.27 log10 CFU/g lungs, -4.95 log10 CFU/mL blood, and -50% mortality). Moreover, the metabolite mix in combination with both antibiotics decreased the bacterial concentrations in the lungs and blood for both A. baumannii strains. In the sepsis model, the significant efficacy of the metabolite mix was restricted to the colistin-susceptible E. coli C1-7-LE strain (-3.32 log10 CFU/g lung, -6.06 log10 CFU/mL blood, and -79% mortality). N-desmethyltamoxifen could be a new therapeutic option in combination with CMS or tigecycline for combating multidrug-resistant GNB, specifically A. baumannii.

Impact of the immune response modification by lysophosphatidylcholine in the efficacy of antibiotic therapy of experimental models of peritoneal sepsis and pneumonia by Pseudomonas aeruginosa: LPC therapeutic effect in combined therapy.

INTRODUCTION: Immune response stimulation may be an adjuvant to antimicrobial treatment. Here, we evaluated the impact of immune response modification by lysophosphatidylcholine (LPC), combined with imipenem or ceftazidime, in murine models of peritoneal sepsis (PS) and pneumonia induced by Pseudomonas aeruginosa. METHODS: The imipenem and ceftazidime-susceptible strain (Pa39) and imipenem and ceftazidime-resistant strain (Pa238) were used. Ceftazidime pharmacokinetic and pharmacodynamic parameters were determined. The therapeutic efficacy and TNF-α and IL-10 levels were determined in murine models of PS and pneumonia induced by Pa39 and Pa238 and treated with LPC, imipenem or ceftazidime, alone or in combination. RESULTS: In the PS model, LPC+ceftazidime reduced spleen and lung Pa238 concentrations (-3.45 and -3.56log10CFU/g; P<0.05) to a greater extent than ceftazidime monotherapy, while LPC+imipenem maintained the imipenem efficacy (-1.66 and -1.45log10CFU/g; P>0.05). In the pneumonia model, LPC+ceftazidime or LPC+imipenem reduced the lung Pa238 concentrations (-2.37log10CFU/g, P=0.1, or -1.35log10CFU/g, P=0.75). For Pa39, no statistically significant difference was observed in the PS and pneumonia models between combined therapy and monotherapy. Moreover, LPC+imipenem and LPC+ceftazidime significantly decreased and increased the TNF-α and IL-10 levels, respectively, in comparison with the untreated controls and monotherapies. CONCLUSIONS: These results demonstrate the impact of immune response modification by LPC plus antibiotics on the prognosis of infections induced by ceftazidime-resistant P. aeruginosa.

Impact of the immune response modification by lysophosphatidylcholine in the efficacy of antibiotic therapy of experimental models of peritoneal sepsis and pneumonia by Pseudomonas aeruginosa: LPC therapeutic effect in combined therapy / Impacto de la modificación de la respuesta inmunitaria por la lisofosfatidilcolina en la eficacia de la terapia antibiótica en un modelo experimental de sepsis peritoneal y de neumonía por Pseudomonas aeruginosa

IntroductionImmune response stimulation may be an adjuvant to antimicrobial treatment. Here, we evaluated the impact of immune response modification by lysophosphatidylcholine (LPC), combined with imipenem or ceftazidime, in murine models of peritoneal sepsis (PS) and pneumonia induced by Pseudomonas aeruginosa.MethodsThe imipenem and ceftazidime-susceptible strain (Pa39) and imipenem and ceftazidime-resistant strain (Pa238) were used. Ceftazidime pharmacokinetic and pharmacodynamic parameters were determined. The therapeutic efficacy and TNF-α and IL-10 levels were determined in murine models of PS and pneumonia induced by Pa39 and Pa238 and treated with LPC, imipenem or ceftazidime, alone or in combination.ResultsIn the PS model, LPC+ceftazidime reduced spleen and lung Pa238 concentrations (−3.45 and −3.56log10CFU/g; P<0.05) to a greater extent than ceftazidime monotherapy, while LPC+imipenem maintained the imipenem efficacy (−1.66 and −1.45log10CFU/g; P>0.05). In the pneumonia model, LPC+ceftazidime or LPC+imipenem reduced the lung Pa238 concentrations (−2.37log10CFU/g, P=0.1, or −1.35log10CFU/g, P=0.75). For Pa39, no statistically significant difference was observed in the PS and pneumonia models between combined therapy and monotherapy. Moreover, LPC+imipenem and LPC+ceftazidime significantly decreased and increased the TNF-α and IL-10 levels, respectively, in comparison with the untreated controls and monotherapies.ConclusionsThese results demonstrate the impact of immune response modification by LPC plus antibiotics on the prognosis of infections induced by ceftazidime-resistant P. aeruginosa.

IntroducciónLa estimulación de la respuesta inmunitaria podría ser adyuvante al tratamiento antimicrobiano. En este estudio, hemos evaluado el impacto de la modificación de la respuesta inmunitaria por la lisofosfatidilcolina (LPC), combinada con imipenem ó ceftazidima, en modelos murinos de sepsis peritoneal (SP) y de neumonía por Pseudomonas aeruginosa (P. aeruginosa).MétodosLa cepa sensible a imipenem y ceftazidima (Pa39) y la cepa resistente a ambos antibióticos (Pa238) fueron usadas. Los parámetros farmacocinéticos/farmacodinámicos de ceftazidima fueron determinados. La eficacia terapéutica y los niveles de TNF-α and IL-10 fueron determinados en los modelos murinos de SP y de neumonía por Pa39 y Pa238 y tratados con LPC, imipenem o ceftazidima, en monoterapia ó en combinación.ResultadosEn el modelo de SP, LPC + ceftazidima redujo la concentración de Pa238 en el bazo y el pulmón (–3,45 y –3,56 log10 UFC/g; p < 0,05) en comparación con ceftazidima, mientras LPC + impenem mantuvo la eficacia de imipenem (–1,66 y –1,45 log10 UFC/g; p > 0,05). En el modelo de neumonía, LPC + ceftazidima o LPC + imipenem redujo la concentración de Pa238 en pulmón (–2,37 log10 UFC/g, p = 0,1 o –1,35 log10 UFC/g, p = 0,75). Para Pa39, no se observó diferencia estadística significativa entre la terapia combinada y la monoterapia en los modelos de SP y de neumonía. Además, LPC + imipenem y LPC + ceftazidime redujeron y aumentaron los niveles de TNF-α y IL-10, respectivamente, en comparación con los controles no tratados y las monoterapias.ConclusionesEstos resultados demuestran el impacto de la modificación de la respuesta inmunitaria por LPC en combinación con antibióticos en el pronóstico de las infecciones por P. aeruginosa ceftazidima-resistente.

Clinical characteristics and outcome of bacteraemia caused by Enterobacter cloacae and Klebsiella aerogenes: more similarities than differences.

OBJECTIVES: The genus Enterobacter is a common cause of nosocomial infections. Historically, the most frequent Enterobacter species were those of Enterobacter cloacae complex and Enterobacter aerogenes. In 2019, E. aerogenes was re-classified as Klebsiella aerogenes owing to its higher genotypic similarity with the genus Klebsiella. Our objective was to characterise and compare the clinical profiles of bacteraemia caused by E. cloacae and K. aerogenes. METHODS: This 3-year multicentre, prospective cohort study enrolled consecutive patients with bacteraemia by E. cloacae or K. aerogenes. Baseline characteristics, bacteraemia features (source, severity, treatment), antibiotic susceptibility, resistance mechanisms and mortality were analysed. RESULTS: The study included 285 patients with bacteraemia [196 (68.8%) E. cloacae and 89 (31.2%) K. aerogenes]. The groups showed no differences in age, sex, previous use of invasive devices, place of acquisition, sources or severity at onset. The Charlson score was higher among patients with E. cloacae bacteraemia [2 (1-4) vs. 1 (0.5-3); P = 0.018], and previous antibiotic therapy was more common in patients with K. aerogenes bacteraemia (57.3% vs. 41.3%; P = 0.01). Mortality was 19.4% for E. cloacae and 20.2% for K. aerogenes (P = 0.869). Antibiotic susceptibility was similar for both species, and the incidence of multidrug resistance or ESBL production was low (6% and 5.3%, respectively), with no differences between species. CONCLUSION: Bacteraemias caused by E. cloacae and K. aerogenes share similar patient profiles, presentation and prognosis. Patients with E. cloacae bacteraemia had more co-morbidities and those with K. aerogenes bacteraemia had received more antibiotics.

Repurposing of the Tamoxifen Metabolites to Combat Infections by Multidrug-Resistant Gram-Negative Bacilli.

The development of new strategic antimicrobial therapeutic approaches, such as drug repurposing, has become an urgent need. Previously, we reported that tamoxifen presents therapeutic efficacy against multidrug-resistant (MDR) Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli in experimental infection models by modulating innate immune system cell traffic. The main objective of this study was to analyze the activity of N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen, three major metabolites of tamoxifen, against these pathogens. We showed that immunosuppressed mice infected with A. baumannii, P. aeruginosa, or E. coli in peritoneal sepsis models and treated with tamoxifen at 80 mg/kg/d for three days still reduced the bacterial load in tissues and blood. Moreover, it increased mice survival to 66.7% (for A. baumannii and E. coli) and 16.7% (for P. aeruginosa) when compared with immunocompetent mice. Further, susceptibility and time-kill assays showed that N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen exhibited minimum inhibitory concentration of the 90% of the isolates (MIC90) values of 16 mg/L, and were bactericidal against clinical isolates of A. baumannii and E. coli. This antimicrobial activity of tamoxifen metabolites paralleled an increased membrane permeability of A. baumannii and E. coli without affecting their outer membrane proteins profiles. Together, these data showed that tamoxifen metabolites presented antibacterial activity against MDR A. baumannii and E. coli, and may be a potential alternative for the treatment of infections caused by these two pathogens.

Impact of the immune response modification by lysophosphatidylcholine in the efficacy of antibiotic therapy of experimental models of peritoneal sepsis and pneumonia by Pseudomonas aeruginosa: LPC therapeutic effect in combined therapy.

INTRODUCTION: Immune response stimulation may be an adjuvant to antimicrobial treatment. Here, we evaluated the impact of immune response modification by lysophosphatidylcholine (LPC), combined with imipenem or ceftazidime, in murine models of peritoneal sepsis (PS) and pneumonia induced by Pseudomonas aeruginosa. METHODS: The imipenem and ceftazidime-susceptible strain (Pa39) and imipenem and ceftazidime-resistant strain (Pa238) were used. Ceftazidime pharmacokinetic and pharmacodynamic parameters were determined. The therapeutic efficacy and TNF-α and IL-10 levels were determined in murine models of PS and pneumonia induced by Pa39 and Pa238 and treated with LPC, imipenem or ceftazidime, alone or in combination. RESULTS: In the PS model, LPC+ceftazidime reduced spleen and lung Pa238 concentrations (-3.45 and -3.56log10CFU/g; P<0.05) to a greater extent than ceftazidime monotherapy, while LPC+imipenem maintained the imipenem efficacy (-1.66 and -1.45log10CFU/g; P>0.05). In the pneumonia model, LPC+ceftazidime or LPC+imipenem reduced the lung Pa238 concentrations (-2.37log10CFU/g, P=0.1, or -1.35log10CFU/g, P=0.75). For Pa39, no statistically significant difference was observed in the PS and pneumonia models between combined therapy and monotherapy. Moreover, LPC+imipenem and LPC+ceftazidime significantly decreased and increased the TNF-α and IL-10 levels, respectively, in comparison with the untreated controls and monotherapies. CONCLUSIONS: These results demonstrate the impact of immune response modification by LPC plus antibiotics on the prognosis of infections induced by ceftazidime-resistant P. aeruginosa.

CNS infections in patients with temporary CSF shunts: Diagnostic, preventive and therapeutic approach / Infecciones del SNC en pacientes con drenaje ventricular externo: aproximación diagnóstica, preventiva y terapéutica

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Efficacy and safety of a comprehensive educational antimicrobial stewardship program focused on antifungal use.

OBJECTIVE: Few data exist regarding the impact of antimicrobial stewardship programs on antifungal use. We evaluated the efficacy and safety of a comprehensive long-term antimicrobial stewardship program (ASP) focused on antifungal use. METHODS: During a 9-year period, we quarterly assessed antifungal consumption, incidence density of hospital-acquired candidemia, Candida spp. distribution, antifungal resistance, and crude death rate per 1000 occupied bed days (OBDs) of hospital-acquired candidemia. We performed segmented regression analysis of interrupted time series. RESULTS: A significant change in trend was observed for antifungal consumption, with a sustained reduction of -0.87% per quarter (95% confidence interval [CI], -1.36 -0.38, p < 0.001), accounting for a final reduction of -38.4%. The main reduction was produced in fluconazole, with a sustained reduction of -1.37% per quarter (95%CI, -1.96 -0.68, p<0.001). The incidence density of hospital-acquired candidemia decreased, with a change in slope of -5.06% cases per 1000 OBDs per year (95%CI, -8.23 -1.77, p = 0.009). The 14-day crude death rate per 1000 OBDs dropped from 0.044 to 0.017 (-6.36% deaths per 1000 OBDs per year; 95%CI, -13.45 -1.31, p = 0.09). CONCLUSIONS: This ASP has succeeded in optimizing the use of antifungal with a long-lasting reduction without increasing the incidence, neither the mortality, of hospital-acquired candidemia.

Long-Term Impact of an Educational Antimicrobial Stewardship Program on Hospital-Acquired Candidemia and Multidrug-Resistant Bloodstream Infections: A Quasi-Experimental Study of Interrupted Time-Series Analysis.

BACKGROUND: The global crisis of bacterial resistance urges the scientific community to implement intervention programs in healthcare facilities to promote an appropriate use of antibiotics. However, the clinical benefits or the impact on resistance of these interventions has not been definitively proved. METHODS: We designed a quasi-experimental intervention study with an interrupted time-series analysis. A multidisciplinary team conducted a multifaceted educational intervention in our tertiary-care hospital over a 5-year period. The main activity of the program consisted of peer-to-peer educational interviews between counselors and prescribers from all departments to reinforce the principles of the proper use of antibiotics. We assessed antibiotic consumption, incidence density of Candida and multidrug-resistant (MDR) bacteria bloodstream infections (BSIs) and their crude death rate per 1000 occupied bed days (OBDs). RESULTS: A quick and intense reduction in antibiotic consumption occurred 6 months after the implementation of the intervention (change in level, -216.8 defined daily doses per 1000 OBDs; 95% confidence interval, -347.5 to -86.1), and was sustained during subsequent years (average reduction, -19,9%). In addition, the increasing trend observed in the preintervention period for the incidence density of candidemia and MDR BSI (+0.018 cases per 1000 OBDs per quarter; 95% confidence interval, -.003 to .039) reverted toward a decreasing trend of -0.130 per quarter (change in slope, -0.029; -.051 to -.008), and so did the mortality rate (change in slope, -0.015; -.021 to -.008). CONCLUSIONS: This education-based antimicrobial stewardship program was effective in decreasing the incidence and mortality rate of hospital-acquired candidemia and MDR BSI through sustained reduction in antibiotic use.

Cryptococcal Infection of the Ventriculoperitoneal Shunt in an HIV-Infected Patient with an Excellent Immunovirologic Status.

BACKGROUND: Cryptococcus spp. is a rare cause of ventriculoperitoneal shunt (VPS) infection, with a variable clinical presentation. Diagnosis and treatment of this entity are challenging. CASE DESCRIPTION: A cryptococcal VPS infection occurred in a human immunodeficiency virus-infected patient with an excellent immunovirologic status, with an abdominal mass as the only clinical sign at presentation. Microbiologic diagnosis was confirmed when Cryptococcus neoformans was isolated in 4 cerebrospinal fluid samples on different days. The patient was treated with dual antifungal therapy (liposomal amphotericin B plus flucytosine). The VPS was initially externalized and then removed. At 12-month follow-up, the patient remained asymptomatic, and no replacement VPS was required. CONCLUSIONS: This is the first reported case of cryptococcal VPS infection in a patient with human immunodeficiency virus infection. Clinical outcome was excellent after dual antifungal therapy plus device withdrawal. Diagnosis and treatment of this entity remain a challenge for clinicians.

Avoiding pullout complications in external ventricular drains: technical note.

This report describes a reliable and simple technique for securing external ventricular drains (EVDs) to the scalp and avoiding pullout complications. The operative technique consists of fixing the drain between 2 hydrocolloid dressings and securing it with staples. A 10-year retrospective analysis of EVD pullout complications was performed in a series of 435 consecutive patients who were treated at a single institution. The EVD pullout complication rate was 0.4%. No complications related to the fixation technique were found. The median operative time required to fix the drain was 60 seconds. The technique presented here is a simple and reliable procedure to fix the EVD to the scalp, preventing pullout complications and thus reducing the morbidity of EVD reimplantation.

Maraviroc Clinical Test (MCT) as an alternative tool to decide CCR5-antagonists prescription in naïve HIV-infected patients.

Our aim was to analyze the virological response to a combined antiretroviral therapy started after Maraviroc Clinical Test (MCT) in naïve HIV-infected patients. Forty-one patients were exposed to MCT, based on an 8-day MVC monotherapy. If undetectability or a viral load reduction >1 log10 HIV-RNA copies/ml was achieved, a MVC-containing cART was prescribed. Forty patients showed a positive MCT; undetectability after 48weeks on cART was achieved in 34/41 (82.9%) patients. The result of MCT was compared with a genotypic tropism method and with Trofile®, showing 10.7% and 18.75% discordance rates, respectively. MCT is a reliable tool to decide CCR5-antagonists prescription, also in the naïve scenario where most patients show a virological response to MVC independently the tropism result reported by genotypic or phenotypic methods.

Efficacy of linezolid versus a pharmacodynamically optimized vancomycin therapy in an experimental pneumonia model caused by methicillin-resistant Staphylococcus aureus.

OBJECTIVES: The British Thoracic Society, American Thoracic Society and Infectious Diseases Society of America guidelines recommend vancomycin for methicillin-resistant Staphylococcus aureus (MRSA) pneumonia, based on evidence suggesting that a vancomycin AUC0₋24/MIC ratio of 400 predicts clinical success against MRSA pneumonia. The aim of this study was the evaluation of an optimized dose of vancomycin in the treatment of MRSA experimental pneumonia versus linezolid. METHODS: In vitro activities of vancomycin and linezolid were tested using time-kill curves. Experimental pneumonia in neutropenic C57BL/6 mice was achieved using two clinical MRSA strains, MR30 and MR33 (vancomycin and linezolid MICs of 1 and 4 mg/L, respectively). In vivo dosages were 30 and 110 mg/kg vancomycin (obtaining an AUC0₋24/MIC ratio lower and higher than 400, respectively), and 30 mg/kg linezolid. RESULTS: Survival rates in controls, and in the groups treated with 120 mg/kg/day vancomycin, 440 mg/kg/day vancomycin and 120 mg/kg/day linezolid were 85.7%, 92.9%, 76.9% and 100%, and 66.7%, 100%, 75% and 100% for MR30 and MR33, respectively. Sterile blood cultures occurred at rates of 21.4%, 64.3%, 100% and 93.8%, and 40%, 66.7%, 100% and 93.3% for MR30 and MR33 strains, respectively. Finally, the respective bacterial lung concentrations (log10 cfu/g) were 8.93 ±â€Š0.78, 6.67 ±â€Š3.01, 3.25 ±â€Š1.59 and 2.87 ±â€Š1.86 for MR30, and 8.62 ±â€Š0.72, 5.76 ±â€Š2.43, 3.97 ±â€Š1.52 and 1.59 ±â€Š1.40 for MR33. CONCLUSIONS: These results support that a vancomycin AUC0₋24/MIC ratio >400 is necessary to obtain a high bacterial lung reduction in MRSA pneumonia, comparable to that achieved with linezolid and better than that with the low dose of vancomycin tested. Linezolid was more efficacious than the pharmacodynamically optimized vancomycin dose in the pneumonia caused by the most virulent strain (MR33).

Methicillin-resistant Staphylococcus aureus meningitis in adults: a multicenter study of 86 cases.

Methicillin-resistant Staphylococcus aureus (MRSA) meningitis is an uncommon disease, and little is known about its epidemiology, clinical features, therapy, and outcome. We performed a multicenter retrospective study of MRSA meningitis in adults. Eighty-six adult patients were included and the following data were obtained: underlying diseases, clinical presentation, analytical and microbiologic data, response to therapy, and outcome.There were 56 men (65%) and the mean age was 51.5 years; 54 of them (63%) had severe comorbidities. There were 78 cases of postoperative meningitis and 8 of spontaneous meningitis. The infection was nosocomial in 93% (80/86) of the cases. Among the 78 patients with postoperative meningitis, the most common predisposing conditions were cerebrospinal fluid (CSF) devices (74%), neurosurgery (45%), CSF leakage (17%), and head trauma (12%). Most patients had fever (89%), altered mental status (68%), headache (40%), and meningeal signs (29%). The most common CSF findings were pleocytosis (90%), elevated protein level (77%), and hypoglycorrhachia (30%). CSF Gram stain and blood cultures were positive in 49% (32/65) and 36% (16/45) of cases, respectively. An associated MRSA infection and polymicrobial meningitis appeared in 33% (28/86) and 23% (20/86) of cases, respectively. Antimicrobial therapy was given to 84 patients. Most of them received vancomycin (92%) either as monotherapy (64%) or in combination with other antibiotics (28%), for a median of 18 days. Overall 30-day mortality was 31% (27/86). Multivariate study identified 2 independent factors associated with mortality: spontaneous meningitis (odds ratio [OR], 21.4; 95% confidence interval [CI], 2.3-195.4; p = 0.007), and coma (OR, 9.7; 95% CI, 2.2-42.3; p = 0.002).In conclusion, MRSA is a relatively uncommon but serious disease. Although most cases are nosocomial infections appearing in neurosurgical patients, spontaneous meningitis may present as a community-onset infection in patients with severe comorbidities requiring frequent contact with the health care system. Most patients have a favorable response to vancomycin, but the beneficial effect of combined and intraventricular therapy, or alternative drugs, remains unclear. MRSA meningitis is associated with a high mortality, and the presence of spontaneous infection and coma are the most important prognostic factors.

Infecciones de derivaciones de líquido cefalorraquídeo. Factores de riesgo, controversias, tratamiento y perspectivas futuras / Cerebrospinal fluid shunt infections. Risk factors, controversies, management and future perspectives

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Efficacy of rifampin and its combinations with imipenem, sulbactam, and colistin in experimental models of infection caused by imipenem-resistant Acinetobacter baumannii.

There are currently no defined optimal therapies available for multidrug-resistant (MDR) Acinetobacter baumannii infections. We evaluated the efficacy of rifampin, imipenem, sulbactam, colistin, and their combinations against MDR A. baumannii in experimental pneumonia and meningitis models. The bactericidal in vitro activities of rifampin, imipenem, sulbactam, colistin, and their combinations were tested using time-kill curves. Murine pneumonia and rabbit meningitis models were evaluated using the A. baummnnii strain Ab1327 (with MICs for rifampin, imipenem, sulbactam, and colistin of 4, 32, 32, and 0.5 mg/liter, respectively). Mice were treated with the four antimicrobials and their combinations. For the meningitis model, the efficacies of colistin, rifampin and its combinations with imipenem, sulbactam, or colistin, and of imipenem plus sulbactam were assayed. In the pneumonia model, compared to the control group, (i) rifampin alone, (ii) rifampin along with imipenem, sulbactam, or colistin, (iii) colistin, or (iv) imipenem plus sulbactam significantly reduced lung bacterial concentrations (10.6 +/- 0.27 [controls] versus 3.05 +/- 1.91, 2.07 +/- 1.82, 2.41 +/- 1.37, 3.4 +/- 3.07, 6.82 +/- 3.4, and 4.22 +/- 2.72 log(10) CFU/g, respectively [means +/- standard deviations]), increased sterile blood cultures (0% versus 78.6%, 100%, 93.3%, 93.8%, 73.3%, and 50%), and improved survival (0% versus 71.4%, 60%, 46.7%, 43.8%, 40%, and 85.7%). In the meningitis model rifampin alone or rifampin plus colistin reduced cerebrospinal fluid bacterial counts (-2.6 and -4.4 log(10) CFU/ml). Rifampin in monotherapy or with imipenem, sulbactam, or colistin showed efficacy against MDR A. baumannii in experimental models of pneumonia and meningitis. Imipenem or sulbactam may be appropriate for combined treatment when using rifampin.

[Infection of cerebrospinal fluid shunt systems]. / Infecciones relacionadas con los sistemas de drenaje de líquido cefalorraquídeo.

Cerebrospinal fluid (CSF) shunt infection is a cause of considerable morbidity and mortality. Shunt infection is produced mainly during surgery and by surgical wound infection. Staphylococcus spp. (> 50% methicillin-resistant) are the most common causative bacteria, although gram-negative bacilli (10%-25%) and Propionibacterium acnes are becoming increasingly implicated. Shunt malfunction syndrome and fever are the most frequent clinical manifestations, whereas signs of meningeal irritation are uncommon. Other clinical manifestations depend on the location of the distal catheter. CSF should be obtained by puncture of the shunt reservoir or the distal catheter and processed for biochemical analyses, cell count, Gram stain, and aerobic and anaerobic cultures (lengthy incubation). Because of biofilm formation and to avoid recurrences, the recommended treatment is intravenous antibiotics plus removal of all components of the infected shunt, followed by placement of an external drainage catheter and a new shunt. Prophylaxis is important and can include antimicrobial prophylaxis and/or antibiotic-impregnated catheters.