Local administration of polymyxins into the respiratory tract for the prevention and treatment of pulmonary infections in patients without cystic fibrosis.

The increasing problem of antimicrobial resistance has forced the medical community to evaluate alternative preventive and therapeutic strategies for nosocomial pneumonia, infection that is associated with considerable morbidity and mortality. Among them, local administration of polymyxins into the respiratory tract represents a promising strategy. This review highlights recent evidence regarding the effectiveness and safety of this intervention in the prevention and treatment of patients with multidrug-resistant Gram-negative bacterial infections. Polymyxins can be administered directly to the respiratory tract through jet or ultrasonic nebulizers, dry powder inhalers, or by endotracheal instillation. Data from limited studies on pharmacokinetic and pharmacodynamic properties of aerosolized polymyxins suggest that while high sputum concentrations are achievable systemic exposure is limited. The incidence of colonization of the upper respiratory tract with Gram-negative bacteria, especially Pseudomonas aeruginosa was considerably reduced in two trials that assessed the effect of prophylactic administration of aerosolized polymyxins on the colonization of the respiratory tract of critically ill patients. Clinical trials that examined the value of aerosolized polymyxins in the prevention of lung infections resulted in conflicting findings. Although the incidence of Gram-negative bacterial pneumonia was decreased in the majority of the studies, no improvement in mortality was found. Possible selection of polymyxin-resistant microorganisms has been the major limitation. Treatment of Gram-negative bacterial nosocomial pneumonia with aerosolized polymyxins may be a beneficial supplemental to the conventional therapy; however, its value remains to be proved. The available evidence supports that the local administration of polymyxins into the respiratory tract for the prevention and treatment of multidrug-resistant (MDR) Gram-negative bacterial infections deserves further investigation.

Effectiveness and nephrotoxicity of colistin monotherapy vs. colistin-meropenem combination therapy for multidrug-resistant Gram-negative bacterial infections.

A retrospective cohort study evaluated the effectiveness and nephrotoxicity of intravenous colistin monotherapy vs. colistin-meropenem combination therapy for patients with multidrug-resistant Gram-negative bacterial infections. Fourteen patients received intravenous colistin monotherapy and 57 received colistin-meropenem. No significant differences were found concerning clinical response of the infection (12/14 (85.7%) vs. 39/57 (68.4%), p 0.32) and development of nephrotoxicity (0/14 (0%) vs. 4/57 (7%), p 0.58). A favourable association was revealed between survival and treatment with colistin monotherapy compared to colistin-meropenem (0/14 (0%) vs. 21/57 (36.8%) deaths, p 0.007), even after adjusting for the variables for which significant differences were found.

Effectiveness and nephrotoxicity of intravenous colistin for treatment of patients with infections due to polymyxin-only-susceptible (POS) gram-negative bacteria.

The prospective case series study presented here was conducted to assess the outcome of patients with infections caused by polymyxin-only-susceptible (POS) gram-negative bacteria managed with intravenous colistin. Between July 2003 and April 2005 a total of 27 patients were infected with a POS gram-negative bacterium and received intravenous colistin at a dose of 2 million international units (MIU) (160 mg or 66.7 mg colistin base) every 8 h for a mean (+/-SD) duration of 13.9 (+/-7.5) days. Nine patients had ventilator-associated pneumonia and received, in addition to the intravenous colistin therapy, 1 MIU (80 mg or 33.3 mg colistin base) aerosolized colistin every 12 h for a mean (+/-SD) duration of 13 (+/-6.5) days. The predominant pathogens were Pseudomonas aeruginosa (n = 17) and Acinetobacter baumannii (n = 12); in two patients both pathogens were isolated from one clinical specimen. In-hospital mortality and clinical response were 15% and 85%, respectively. Colistin-associated nephrotoxicity was observed in two of the 27 patients. POS gram-negative pathogens represent a major threat for hospitalized patients. Colistin appears to be an effective and safe treatment, even in patients with severe underlying diseases.

Mesh-related infection after hernia repair: case report of an emerging type of foreign-body related infection.

The use of a mesh has been an advance in hernia repair and subsequently has become prevalent worldwide. However, the use of mesh may be associated with both non-infectious and infectious complications. We present here a representative case of a mesh-related infection due to Staphylococcus aureus and review the available data about the incidence, etiology, clinical manifestations, diagnosis, management, and prevention of this emerging type of foreign body infections.

Mesh-related infections after hernia repair surgery.

Clinicians have been challenged in the past few years by an increasing variety of novel non-infectious and infectious complications following the widespread use of meshes after open or laparoscopic repair of hernias. The possibility of a mesh-related infection occurring weeks or even years after hernia repair, should be considered in any patient with fever of unknown origin, or symptoms and/or signs of inflammation of the abdominal wall following hernia repair. The reported incidence of mesh-related infection following hernia repair has been 1%-8% in different series, and this incidence is influenced by underlying co-morbidities, the type of mesh, the surgical technique and the strategy used to prevent infections. An approach that combines medical and surgical management is necessary for cases of mesh infection. The antimicrobial treatment regimen chosen initially should include coverage of Staphylococcus spp. and, particularly, Staphylococcus aureus.

Recurrent omphalitis in adults.

Recurrent omphalitis is seen more frequently in children, but clinicians world-wide are occasionally challenged by cases of recurrent omphalitis in adults. Apart from folliculitis and infections associated with pilonidal cysts and piercing of the umbilical area, the clinician should consider the possibility of infected remnants of the allantois or the omphalomesenteric (vitelline) duct in adult patients with recurrent omphalitis. Imaging tests such as ultrasound and computed tomography scan frequently help to identify the exact cause of recurrent omphalitis. The combined surgical and medical management usually leads to cure of the problem.