Novas variantes de KPC em isolados do Complexo Klebsiella pneumoniae resistentes à ceftazidima-avibactam / New KPC variants in ceftazidime-avibactam-resistant K. pneumoniae Complex isolates

O Complexo K. pneumoniae (C-Kp) é o principal grupo de bacilos Gram-negativos responsáveis por infecções nosocomiais graves em todo o mundo e o tratamento empírico dessas infecções usualmente inclui os carbapenêmicos. O principal mecanismo de resistência a essa classe de antimicrobianos é a expressão de carbapenemases, e no Brasil, mais frequentemente as do tipo KPC. Em março de 2019 a ceftazidima-avibactam foi disponibilizada para uso clínico no Brasil, sendo amplamente utilizada no tratamento infecções causadas por bacilos gram-negativos produtores de KPC. Diversos países já relataram a presença de K. pneumoniae produtores de KPC resistentes à ceftazidima-avibactam. No entanto, há poucos relatos dessa ocorrência no Brasil. O objetivo deste trabalho foi caracterizar genotipicamente e fenotipicamente isolados do C-Kp produtores de KPC, resistentes à ceftazidima-avibactam. No período de julho/2019 a julho/2021, 46 isolados do C-Kp, um por paciente, foram detectados em diferentes sítios de infecção ou culturas de vigilância de pacientes internados em hospitais privados de seis estados brasileiros. Os isolados tiveram seu genoma completo sequenciado nas plataformas MiSeq e MinION para determinação da variante alélica de blaKPC e avaliação do seu contexto genético. As taxas de resistência ao ertapenem e à ceftazidima-avibactam foram calculadas a partir de banco de dados. A clonalidade dos isolados foi avaliada por PFGE e MLST. A localização plasmidial do gene blaKPC foi confirmada por conjugação e/ou transformação. A concentração inibitória mínima (CIM) para betalactâmicos foi determinada por microdiluição em caldo segundo o BrCAST. Ensaios imunocromatográficos, NG-Test CARBA-5 e O.K.N.V.I. RESIST-5, foram avaliados quanto à sua performance na detecção de variantes KPC. A taxa de resistência ao ertapenem entre isolados do C-Kp aumentou 15,6% em 2019 para 27,3% em 2021. A taxa de resistência à ceftazidima-avibactam entre isolados do C-Kp resistentes ao ertapenem aumentou de 4,2% em 2019 para 17,2% em 2021. Onze isolados apresentaram novas variantes de KPC designadas KPC-103 a KPC-108 e KPC-139 a KPC-143. Os demais isolados apresentavam variantes de KPC já descritas, sendo a KPC-33 a variante mais frequente (36%). Quinze grupos clonais foram identificados, sendo que a maioria dos isolados pertencia ao ST11. O grupo clonal A foi o mais numeroso e pertencia ao ST258. A principal variante detectada nesse grupo foi a KPC-33. Diferentes grupos de incompatibilidade foram identificados em plasmídeos alberguando blaKPC, sendo os grupos IncN (n=12) e IncF, com replicons FII(K)-FIB (n=11), os grupos mais frequentes, seguido de InX3-IncU (n=9) e IncQ1 (n=1). Dos 46 isolados resistentes à ceftazidima-avibactam, 36 foram capazes de transferir o gene blaKPC para cepas receptoras. A maioria dos isolados foi sensível dose padrão ou sensível aumentabdo exposição ao meropenem e apresentaram redução significativa da CIM quando o avibactam foi adicionado ao aztreonam. O NG-Test CARBA-5 detectou 12 das 24 variantes testadas enquanto que o O.K.N.V.I. RESIST-5 detectou apenas nove variantes. A grande diversidade de variantes KPC, e a predominância do grupo clonal ST11, e da KPC- 33 retratam um cenário preocupante no Brasil

The K. pneumoniae Complex (C-Kp) is the main group of gram-negative bacilli responsible for serious nosocomial infections worldwide and the empirical treatment of these infections usually includes carbapenems. The main mechanism of resistance to this class of antimicrobials is the expression of carbapenemases, and in Brazil, more frequently the KPC type. In March 2019, ceftazidime-avibactam was available for clinical use in Brazil, being widely used to treat infections caused by KPC-producing gram-negative bacilli. Several countries have already reported the presence of KPC-producing K. pneumoniae resistant to ceftazidime-avibactam; however, there are few reports of this occurrence in Brazil. This work aimed to genotypically and phenotypically characterize KPC-producing C-Kp isolates resistant to ceftazidimeavibactam. From July 2019 to July 2021, 46 C-Kp isolates, one per patient, were detected in different sites of infection or surveillance cultures from patients admitted to private hospitals in six Brazilian states. The isolates had their complete genome sequenced on the MiSeq and MinION platforms to determine the allelic variant of blaKPC and evaluate its genetic context. Resistance rates to ertapenem and ceftazidime-avibactam were calculated from a database. The clonality of the isolates was evaluated by PFGE and MLST. The plasmid location of the blaKPC gene was confirmed by conjugation and/or transformation. The minimal inhibitory concentrations for beta-lactams were determined by broth microdilution according to BrCAST. Immunochromatographic assays, NG-Test CARBA-5 and O.K.N.V.I. RESIST-5, were evaluated for its performance in detecting KPC variants. The resistance rate to ertapenem among C-Kp isolates increased from 15.6% in 2019 to 27.3% in 2021. The resistance rate to ceftazidime-avibactam among ertapenem-resistant C-Kp isolates increased from 4.2% in 2019 to 17.2% in 2021. Eleven isolates showed new KPC variants designated KPC-103 to KPC-108 and KPC-139 to KPC-143. The remaining isolates presented previously described KPC variants, with KPC-33 being the most common variant (36%). Fifteen clonal groups were identified, with most isolates belonging to ST11. Different incompatibility groups were identified in plasmids harboring blaKPC, with the IncN (n=12) and IncF groups, with FII(K)-FIB(n=11) replicons, being the most frequent groups, followed by InX3-IncU (n= 9) and IncQ1 (n=1). All IncX3-IncU plasmids were approximately 46 kb in size and were identified among isolates belonging to the largest identified clonal group (A) and ST258. The main variant detected in this group was KPC-33. Of the 46 ceftazidime-avibactam-resistant isolates, 36 were able to transfer the blaKPC gene to recipient strains. Most isolates were susceptible standard dose or susceptible increased exposure to meropenem and showed a significant decrease in MIC when avibactam was added to aztreonam. The NG-Test CARBA-5 was able to detect 12 of the 24 variants evaluated while the O.K.N.V.I. RESIST-5 detected only nine variants. The great diversity of KPC variants, the predominance of the ST11 clonal group, and KPC-33 portray a worrying scenario in Brazil

Superiority of ceftazidime off-label high-dose regimen in PK/PD target attainment during treatment of extensively drug-resistant Pseudomonas aeruginosa infections in cancer patients.

AIM: The objective of this study was to evaluate off-label high-dose ceftazidime population pharmacokinetics in cancer patients with suspected or proven extensively drug-resistant (XDR) Pseudomonas aeruginosa infections and then to compare the achievement of the pharmacokinetic/pharmacodynamic (PK/PD) target after standard and off-label high-dose regimens using population model-based simulations. A further aim was to clinically observe the occurrence of adverse effects during the off-label high-dose ceftazidime treatment. METHODS: In patients treated with off-label high-dose ceftazidime (3 g every 6 h), blood samples were collected and ceftazidime serum levels measured using LC-MS/MS. A pharmacokinetic population model was developed using a nonlinear mixed-effects modelling approach and Monte Carlo simulations were then used to compare standard and high-dose regimens for PK/PD target attainment. RESULTS: A total of 14 cancer patients with serious infection suspected of XDR P. aeruginosa aetiology were eligible for PK analysis. XDR P. aeruginosa was confirmed in 10 patients as the causative pathogen. Population ceftazidime volume of distribution was 13.23 L, while clearance started at the baseline of 1.48 L/h and increased by 0.0076 L/h with each 1 mL/min/1.73 m2 of eGFR. High-dose regimen showed significantly higher probability of target attainment (i.e., 86% vs. 56% at MIC of 32 mg/L). This was translated into a very low mortality rate of 20%. Only one case of reversible neurological impairment was observed. CONCLUSION: We proved the superiority of the ceftazidime off-label high-dose regimen in PK/PD target attainment with very low occurrence of adverse effects. The off-label high-dose regimen should be used to optimize treatment of XDR P. aeruginosa infections.

Antibiotic allergy in children with cystic fibrosis: A retrospective case-control study.

Antibiotic allergy is a big problem that may affect the treatment and life quality of patients with cystic fibrosis (CF). AIM: To evaluate predictive factors for confirmed antibiotic hypersensitivity in children with CF. METHODS: In this case-controlled study, we examined 15 patients with CF who had been confirmed with antibiotic allergy. Additionally, we included a control group of age- and gender-matched 45 CF patients with no antibiotic allergy. The diagnosis of antibiotic allergy was confirmed in the presence of a compatible history and a positive response in the drug skin test or provocation test. Multiple drug hypersensitivity was classified according to the temporal relationship of antibiotics: (i) distant, (ii) simultaneous, and (iii) sequential. The data were analyzed by conditional logistic regression. RESULTS: ß-lactam allergy was confirmed in eight patients (ceftazidime n = 5, piperacillin-tazobactam n = 3) and non-ß-lactam allergy was confirmed in two patients (ciprofloxacin n = 1, azithromycin n = 1). Additionally, multiple drug hypersensitivity in five patients (distant n = 4, sequential n = 1), among whom two patients showed hypersensitivity against ceftazidime/piperacillin-tazobactam+ ciprofloxacin/levofloxacin, two patients showed hypersensitivity against ceftazidime+ ciprofloxacin n = 2, and one patient showed hypersensitivity against piperacillin-tazobactam+ amikacin+ trimethoprim-sulfamethoxazole. All patients (n = 13) with confirmed ß-lactam allergy were meropenem tolerant. Multivariate analysis indicated that immediate reactions (, p < 0.001) and allergic evaluation in the first six months after the reaction (p = 0.036) were significant risk factors for the prediction of antibiotic hypersensitivity. CONCLUSION: Beta-lactam antibiotic allergy is the most commonly confirmed drug allergy in children with CF. However, unlike normal children, ceftazidime and piperacillin-tazobactam account for the majority.

Meta-analysis: combination of meropenem vs ceftazidime and amikacin for empirical treatment of cancer patients with febrile neutropenia.

BACKGROUND: Meropenem monotherapy vs ceftazidime plus amikacin have been approved for use against febrile neutropenia. To assess the effectiveness and safety of them for empirical treatment of cancer patients with febrile neutropenia, we conducted a meta-analysis of randomized controlled trial. METHODS: Randomized controlled trials on ceftazidime plus amikacin, or/and monotherapy with meropenem for the treatment of cancer patients with febrile neutropenia were identified by searching Cochrane Library, PubMed, Science Direct, Wiley Online, Science Citation Index, Google (scholar), National Center for Biotechnology Information, and China National Knowledge Infrastructure. Data on interventions, participants' characteristics and the outcomes of therapy, were extracted for statistical analysis. Seven trials fulfilled the inclusion criteria. RESULT: The treatment with ceftazidime plus amikacin was more effective than meropenem (OR = 1.17; 95% CI 0.93-1.46; 1270 participants). However, the treatment effects of the 2 therapy methods were almost parallel in adults (OR = 1.15; 95% CI 0.91-1.46; 1130 participants older than 16). Drug-related adverse effects afflicted more patients treated with ceftazidime plus amikacin (OR = 0.78; 95% CI 0.52-1.15; 1445 participants). The common responses were nausea, diarrhea, rash, and increased in serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase and bilirubin. CONCLUSION: Ceftazidime plus amikacin should be the first choice for empirical treatment of cancer patients with febrile neutropenia, and meropenem may be chosen as a last defense against pathogenic bacteria.

Indicated and non-indicated antibiotic administration during pregnancy and its effect on pregnancy outcomes: Role of inflammation.

The objective of this study was to compare the release of endotoxin and pro-inflammatory cytokines as well as pregnancy outcomes after antibiotic exposure in healthy and bacterial infected pregnant rats. Thirty female Wistar pregnant rats were divided into five groups. Group A considered as control and received intraperitoneal saline 0.9% on 17th day of gestation or DG) and groups B and C treated with 20 mg/kg/day intravenous ceftriaxone and ceftazidime, respectively (DG: 18-20). Groups D and E received intraperitoneal E. coli and LPS on 17th DG respectively. Also, groups F and G received the same treatment as group D but they treated with the exact antibiotics mentioned for groups B and C (same dose and duration). Pregnancy outcomes as well as maternal sera levels of endotoxin, tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß), and IL-6 were assessed using enzyme-linked immunosorbent assay. It was shown that group B had a higher IL-1ß (P = 0.003) and TNF-α (P = 0.003) levels compared to the controls (CTC). Group C expressed a lower gestational duration (P = 0.007) as well as higher IL-6 (P = 0.025) and TNF-α (P < 0.001) levels CTC. Interestingly, both group B (P = 0.021) and C (P < 0.001) had a higher rate of endotoxin release CTC. Moreover, in group C, IL-6 (P < 0.0001 and r = -0.941) had a significant correlation with gestational duration. As the results showed, antibiotic administration in non-indication condition seems to be associated with significantly higher production of endotoxin and inflammatory cytokines which increase the risk of poor pregnancy outcomes.

Acute kidney injury as the presenting complaint of ceftazidime-induced immune-mediated haemolysis.

We present the case of ceftazidime-induced immune-mediated haemolysis with associated acute kidney injury in a 43-year-old woman. The patient initially presented to the regional cystic fibrosis centre for treatment of an infective exacerbation of cystic fibrosis. After initiation of ceftazidime (a third-generation cephalosporin), renal function rapidly deteriorated and a fall in haemoglobin was noted. On transfer to our care, a haemolysis screen identified immune-mediated haemolysis, and renal biopsy confirmed the finding of acute tubular necrosis secondary to haem pigment. The patient's renal function deteriorated such that she required haemodialysis, although she subsequently recovered and is now dialysis-independent. Although acute haemolytic reactions are recognised with third-generation cephalosporins, this is the first reported case of ceftazidime-induced immune-mediated haemolysis with acute kidney injury. Given the increased frequency of cephalosporin usage, it is important for both nephrologists and general physicians to be aware of this rare but very serious complication.

Ceftazidime-induced thrombocytopenia. / Trombocitopenia inducida por ceftazidima.

Ceftazidime is an antibiotic belonging to the group of third generation cephalosporins, frequently used in clinical practice for its broad antibacterial spectrum. A case report is presented on a 78-year-old man who entered the intensive care unit due to respiratory failure secondary to nosocomial pneumonia in the postoperative period of a laparoscopic hepatic bisegmentectomy for a hepatocarcinoma. It required invasive mechanical ventilation and was treated with ceftazidime, developing a progressive decrease in platelet count after the onset of this drug and after re-exposure to it, not coinciding with the introduction of other drugs. The adverse reaction was reported to the Spanish pharmacosurveillance system and according to the Naranjo algorithm the causal relationship was probable. Since no case of ceftazidime-induced thrombocytopenia was found in the literature, we consider knowledge of it relevant as an adverse effect to be taken into account given its potential severity, especially when it cannot be explained by other causes.

Phase I study assessing the safety, tolerability, and pharmacokinetics of avibactam and ceftazidime-avibactam in healthy Japanese volunteers.

Avibactam is a novel non-ß-lactam ß-lactamase inhibitor that has been shown to restore the in vitro activity of ceftazidime against pathogens producing Ambler class A, C, and some class D ß-lactamases. This study aimed to evaluate the safety, tolerability, and pharmacokinetics of single and multiple doses of avibactam alone or with ceftazidime in healthy Japanese subjects. In this Phase I, double-blind study (NCT01291602), 16 healthy Japanese males, mean age 28.8 years, were randomized in a 2:2:1 ratio to receive avibactam 500 mg (n = 6), ceftazidime 2000 mg plus avibactam 500 mg (n = 7), or placebo (n = 3), each administered as a 100 ml intravenous infusion over 2 h, once on Day 1, every 8 h on Days 3-6, and once on Day 7. There were no deaths or serious adverse events. Nine treatment-emergent adverse events were reported in three subjects in the avibactam group - including one elevation in transaminase levels, and three vital signs events (tachycardia, palpitations, and orthostatic hypotension) - and one in the ceftazidime-avibactam group. All events were considered mild. After single or multiple dosing, plasma concentrations of avibactam and ceftazidime declined in a multi-exponential manner. No plasma concentration accumulation was observed, and the majority of avibactam was excreted unchanged in urine within 24 h. No clinically relevant changes in intestinal bacterial flora were observed. In conclusion, avibactam alone and ceftazidime-avibactam were generally well tolerated in healthy male Japanese subjects, and avibactam pharmacokinetics were comparable whether administered alone or in combination with ceftazidime.

The safety of cefepime and ceftazidime in pediatric oncology patients.

BACKGROUND: Concern has been raised about possible increased mortality associated with the use of cefepime. There are limited data available on the pragmatic use of beta-lactam antibiotics, especially in children. PROCEDURE: This retrospective study included 532 pediatric oncology patients. The outcomes of patients treated with cefepime for suspected serious bacterial infections were compared to those of patients treated with ceftazidime. Primary outcomes included 30- and 90-day all-cause mortality. RESULTS: The demographic and clinical characteristics of 337 patients treated with ceftazidime were similar to those of 195 patients receiving cefepime. Thirty-day and 90-day all cause mortality rates were comparable (30-day OR for cefepime: 3.48, 95% CI 0.31-38.84, P = 0.3; 90-day OR: 0.99, 95% CI 0.29-3.42, P = 1.0). There were also no differences in infection-related mortality rates, secondary infections, or adverse drug events. Deaths occurring within 30 days of hospitalization were judged to be attributable to infection, but not the result of treatment failure or adverse drug events. Deaths occurring between 30 and 90 days were associated with progressive or new malignancy. Secondary infection was significantly associated with mortality. CONCLUSIONS: The use of cefepime in pediatric oncology patients is not associated with increased mortality when compared to ceftazidime, however the small number of deaths in this study limits the strength of this conclusion. Previous associations between antimicrobial therapy and increased all-cause mortality may have been confounded by patients' demographic characteristics and co-morbid conditions. All-cause mortality may be an insensitive outcome for studies examining the efficacy and safety of these agents.

[The prophylactic effect of ceftazidime on early bacterial infection after autologous peripheral blood stem cell transplantation: a prospective randomized controlled trial].

OBJECTIVE: To evaluate the efficacy and safety of prophylactic ceftazidime on early bacterial infection in APBSCT recipients during neutropenia. METHODS: APBSCT recipients were prospectively randomly assigned to intravenous ceftazidime treatment group and control group (no prophylaxis of antibiotics). The treatment started from the first day until resolution of neutropenia or the appearance of early bacterial infection. RESULTS: From March 2010 to January 2013, 70 APBSCT recipients were enrolled in the study with 36 in treatment and 34 in control group. Overall, 29(41.4%) patients developed early bacterial infection, among which, 9(25.0%) in the treatment group and 20(58.8%) in the control group (P = 0.004). The median infection free survival (IFS) was not reached in the treatment group and was 8 days in the control group (P = 0.005). Despite whether patients received single high dose melphalan or other conditioning regimes, the early bacterial infection rate was lower in the treatment group than in the control group, and the median IFS was longer in the treatment group than that in the control group. The mean courses of antibiotic administration were (8.08 ± 2.03) days and (3.68 ± 3.56) days respectively in the treatment and control groups (P < 0.001). However, the duration of empirical carbapenems were (1.67 ± 3.03) days and (3.68 ± 3.56) days respectively (P = 0.013). There was no significant difference of antibiotics cost per patient between the two groups. Four patients in the treatment group had a transient elevated serum creatinine. Overall, no infection related mortality was observed in either group. CONCLUSIONS: Prophylaxis of intravenous ceftazidime for APBSCT recipients is effective in preventing early bacterial infection with an acceptable toxicity and cost profile. However, it doesn't have effect on infection related mortality. Therefore, our results do not support the use of antibiotic prophylaxis for patients undergoing APBSCT.

Amoxicillin and clavulanic acid vs ceftazidime in the surgical extraction of impacted third molar: a comparative study.

The objective of this work is to compare the effectiveness and the side effects of two different drugs, amoxicillin and clavulanic acid vs ceftazidime, used as antibiotic prophylaxis in the surgical extraction of third molars and to demonstrate that the use of second choice antibiotic has no significant advantages in comparison with a first choice antibiotic. One hundred and seven patients with impacted third molar were selected and divided into two groups: amoxicillin and clavulanic acid were administered to group 1 and ceftazidime to group 2 for five days after surgery and we observed the postoperative period. The statistical analysis showed no differences between the two groups which lead to the conclusion that there is no indication to routinely administrate intramuscular second-choice antibiotic prophylatic therapy (ceftazidime) in case of surgical extraction of the third molar.

Nonimmediate ß-lactam reactions in patients with cystic fibrosis.

PURPOSE OF REVIEW: The aim of this review is to present and discuss new developments regarding ß-lactam hypersensitivity in patients with cystic fibrosis. It is a common complication that can have significant implications for a patient. Up to 30% of patients have had multiple ß-lactam reactions. RECENT FINDINGS: For the first time drug-specific lymphocytes have been identified in patients with cystic fibrosis. This supports the clinical viewpoint that the nonimmediate reactions seen are T-cell mediated. Furthermore, in piperacillin hypersensitivity mass spectrometric methods have been used to characterise hapten formation both in vivo and in vitro. The synthetic piperacillin-albumin conjugate is able to stimulate patients' lymphocytes and T cell clones. Lymphocyte proliferation was not seen with ceftazidime; this may be due to undetectable protein reactivity in vitro. Skin testing was not sensitive in this cohort and many patients have uncertain allergy status. Desensitisation is performed with some success; however, at present it is not known whether any immune modulation takes place. SUMMARY: The piperacillin model provides us with a useful tool to characterise the mechanisms of drug hypersensitivity. Prospective studies are needed to assess how drug sensitivity develops and whether clinical practice could be modified to reduce the risk.

Empirical therapy with ceftazidime combined with levofloxacin or once-daily amikacin for febrile neutropenia in patients with neoplasia: a prospective comparative study.

Combination antimicrobial therapy represents common practice in the treatment of febrile neutropenia aiming to broaden the antimicrobial spectrum against Gram-negative pathogens. We did a prospective, non-randomized, comparative study to evaluate ceftazidime plus either levofloxacin or once-daily amikacin as empirical regimens for febrile neutropenia in patients with solid tumor or hematopoietic neoplasm in a region of high baseline resistance prevalence. We included 285 febrile neutropenic episodes in 235 individual patients. One hundred forty-eight cases received levofloxacin and 137 received amikacin, both in combination with ceftazidime. More cases in the levofloxacin than the amikacin group had underlying hematological malignancy; most other characteristics of the two groups were well balanced. Nephrotoxicity requiring treatment discontinuation occurred in one case in the amikacin group. No difference in clinical success (79.7% vs. 80.3%, p>0.99) or all-cause mortality (12.8% vs. 11.7%, p=0.86) was noted between the levofloxacin and the amikacin groups, even after adjustment for the independent predictor variables for each endpoint. Sepsis at presentation, presence of localizing symptoms/signs of infection, and isolation of a non-susceptible Gram-negative pathogen independently predicted both clinical success and all-cause mortality. Additionally, underlying solid tumor independently predicted clinical success, while poor prognosis of the underlying neoplasia and skin/soft tissue infection independently predicted mortality. Ceftazidime plus levofloxacin had similar effectiveness to ceftazidime plus amikacin as empirical regimens for febrile neutropenia. Nephrotoxicity with once-daily amikacin was minimal. Inappropriate empirical therapy was associated with worse prognosis.

Twice vs three-times daily antibiotics in the treatment of pulmonary exacerbations of cystic fibrosis.

BACKGROUND: Once daily dosing of aminoglycosides is widely used but is limited by the inconvenience of the slow infusion it requires and the associated three-times daily infusion of a beta-lactam. Twice daily tobramycin can be given as a slow IV bolus and may be more convenient. This study compares twice with three-times daily dosing of both tobramycin and ceftazidime. METHODS: This was a randomised, open-label, parallel group trial. CF patients presenting with an infective exacerbation were randomised to either twice or three-times daily ceftazidime and tobramycin. Markers of treatment efficacy and safety were measured in the two groups. The primary outcome measure was improvement in FEV1. RESULTS: 146 patients were randomised into the study. There was no significant difference in the two groups for improvement in FEV1% predicted (9.93% and 7.98% for twice daily and three-times daily respectively) and similar times to next exacerbation. There were no differences in the incidence of treatment failure, nephrotoxicity and ototoxicity. DISCUSSION: This study confirms that twice daily dosing of both tobramycin and ceftazidime is safe and effective and may be considered more convenient than current dosing schedules.

[Tolerance and efficacy of ceftazidime in combination with aztreonam for exacerbations of cystic fibrosis]. / Intérêt de l'association ceftazidime et aztréonam dans les exacerbations de mucoviscidose à Pseudomonas aeruginosa multirésistant.

BACKGROUND: Antibiotic therapy for acute pulmonary exacerbations in patients with cystic fibrosis is usually chosen based on the results of antimicrobial susceptibility. This can be difficult when bacteria are multiresistant. The objective of this retrospective study was to evaluate the tolerance and efficiency of ceftazidime and aztreonam combination (+/-tobramycin, +/-ciprofloxacin) in the treatment of acute exacerbations in cystic fibrosis patients who were chronically colonized with multiresistant P. aeruginosa. PATIENTS: Seventeen severe patients, with FEV(1)=1070+/-66 mL and BMI=18+/-0.6 kg/m(2), who had chronic colonisation with P. aeruginosa with intermediate sensitivity or resistance to ceftazidime and aztreonam, were studied between June 2003 and March 2007. Oxygen saturation, dyspnoea, weight, FEV(1), FVC, and tolerance were evaluated before and after antibiotic courses. RESULTS: Forty-two courses of treatment, administered between June 2003 and March 2007 were studied: Patients increased their FEV(1) and FVC (p=0.01). One antibiotic course was stopped after four days because of cutaneous side effects. The median delay until the next exacerbation was 101+/-10 days. These courses were compared with other combinations of antibiotics that the patients had received before. The combination of ceftazidime and aztreonam was more effective in patients receiving less than four courses per year for acute pulmonary exacerbation. CONCLUSION: In chronically P. aeruginosa colonised cystic fibrosis patients, ceftazidime and aztreonam combination (+/-tobramycin, +/-ciprofloxacin) is well tolerated and efficient. This treatment suggests a clinical and functional benefit is possible, even in patients with severe disease.

Continuous versus intermittent infusions of ceftazidime for treating exacerbation of cystic fibrosis.

The present multicenter, randomized crossover study compared the safety and efficacy of continuous infusion with those of short infusions of ceftazidime in patients with cystic fibrosis. Patients with chronic Pseudomonas aeruginosa colonization received two successive courses of intravenous tobramycin and ceftazidime (200 mg/kg of body weight/day) for pulmonary exacerbation administered as thrice-daily short infusions or as a continuous infusion. The primary endpoint was the variation in the forced expiratory volume in 1 s (FEV1) during the course of antibiotic treatment. Sixty-nine of the 70 patients enrolled in the study received at least one course of antibiotic treatment. The improvement in FEV1 at the end of therapy was not statistically different between the two treatment procedures (+7.6% after continuous infusion and +5.5% after short infusions) but was better after continuous ceftazidime treatment in patients harboring resistant isolates (P < 0.05). The interval between the course of antibiotic treatments was longer after the continuous infusion than after the short infusion of ceftazidime (P = 0.04). The mean serum ceftazidime concentration during the continuous infusion was 56.2 +/- 23.2 microg/ml; the mean peak and trough concentrations during the short infusions were 216.3 +/- 71.5 and 12.1 +/- 8.7 microg/ml, respectively. The susceptibility profiles of the P. aeruginosa isolates remained unchanged and were similar for both regimens. Quality-of-life scores were similar whatever the treatment procedure, but 82% of the patients preferred the continuous-infusion regimen. Adverse events were not significantly different between the two regimens. In conclusion, the continuous infusion of ceftazidime did not increase its toxicity and appeared to be as efficient as short infusions in patients with cystic fibrosis as a whole, but it gave better results in patients harboring resistant isolates of P. aeruginosa.

Piperacillin/tazobactam plus ceftazidime versus sulbactam/ampicillin plus aztreonam as empirical therapy for fever in severely neutropenic pediatric patients.

BACKGROUND: The efficacy and safety of piperacillin/tazobactam plus ceftazidime (PIPC/TAZ+CAZ) versus sulbactam/ampicillin plus aztreonam (SBT/ABPC+AZT) as empirical therapy for febrile neutropenia were assessed in children with hematologic disease and solid tumor. PROCEDURE: A prospective randomized study was performed to evaluate the clinical response of 70 febrile episodes in the PIPC/TAZ+CAZ arm and 64 evaluable febrile episodes in the SBT/ABPC+AZT arm of the study. Clinical efficacy was evaluated at 120 hours, with treatment outcome criteria defined as follows. Success was defined as disappearance of fever, clinical improvement, eradication of the infecting organism, and maintenance of a response for at least 7 days after discontinuation of treatment. RESULTS: An infection was documented microbiologically in 14 episodes (20%) in the PIPC/TAZ+CAZ arm and in 8 episodes (13%) in the SBT/ABPC+AZT arm. The success rate was 57.1% in the PIPC/TAZ+CAZ arm and 62.5% in the SBT/ABPC+AZT arm (P>0.05). No major adverse effects were observed in the study. CONCLUSIONS: PIPC/TAZ+CAZ and SBT/ABPC+AZT are effective and safe for initial empirical treatment of febrile episodes in neutropenic pediatric patients. The clinical efficacy of SBT/ABPC+AZT is equivalent or superior to that of PIPC/TAZ+CAZ, the effect of which is already proven against febrile neutropenia. Therefore, SBT/ABPC+AZT may be a treatment of choice for febrile neutropenia in pediatric cancer patients.