Ongoing spread of colistin-resistant Klebsiella pneumoniae in different wards of an acute general hospital, Italy, June to December 2011.

We describe polyclonal spread of colistin-resistant Klebsiella pneumoniae in an acute general hospital in Italy. Between June and December 2011, 58 colistin-resistant K. pneumoniae isolates were recovered from 28 patients admitted to different wards, but mainly in the intensive care units. All isolates were tested for drug susceptibility and the presence of beta-lactamase (bla) genes. Clonality was investigated by repetitive extragenic palindromic (rep)-PCR and multilocus sequence typing (MLST). Fifty-two isolates had minimum inhibitory concentrations (MICs) for colistin of 6-128 mg/L, carried bla(KPC3) and were attributed to sequence type ST258. The remaining six isolates were susceptible to carbapenems, exhibited MICs for colistin of 3-32 mg/L, and belonged to two different types, ST15 and ST273. Rep-PCR included all isolates in three clusters, one containing all ST258 KPC-3-producing isolates and two containing ST15 and ST273 isolates.Cross-transmission containment measures and intensification of staff and environmental hygiene could not stop the outbreak. Selective pressure and horizontal transmission probably contributed to emergence and spread of three different strains of colistin-resistant K. pneumoniae in the hospital. Strict implementation of the above measures and a wider awareness of the antimicrobial resistance threat are crucial to preserve the last therapeutic options of the multidrug-resistant Gram-negative infections.

Daptomycin in the treatment of invasive Gram-positive bacterial infections in children: personal experience.

AIM: The emergence and dissemination of antimicrobial resistance among Gram-positive pathogens has become troublesome for pediatric patients. Daptomycin is a first-in-its-class cyclic lipopeptide, which can be useful for treatment of these infections in children, but clinical experience is lacking. METHODS: Retrospective review of medical records of seven hospitalized children who received daptomycin for treatment of invasive Gram-positive bacterial infections at Children's Cardiosurgery of AORNAS Civico-Di Cristina-Benfratelli, Palermo (Italy), from December 2009 to September 2010. Six patients had a congenital cardiomyopathy; only one patient had not any underlying comorbid condition. Bacterial isolates were tested for susceptibility to daptomycin by gradient diffusion method (E-test, Biomerieux). RESULTS: Seven children received daptomycin. All these children had invasive disease and only one of them was not receiving care in our Intensive Care Unit. Organisms isolated were 2 S. aureus methicillin-resistant; 4 S. Epidermidis methicillin-resistant and 1 E. faecium. Six infections were bloodstream infections and one was a complicated skin and soft tissue infection. All these infections had failed standard empirical antimicrobial therapy and had persistently positive blood cultures and/or fever prior to initiation of daptomycin. Outcomes after the initiation of daptomycin included clearance of blood cultures and defervescence within 72 hours. No drug related adverse events were documented. CONCLUSION: All our patients improved but two patients died of complications of their pre-existing pathology. Further studies are necessary to assess the pharmacological characteristics, safety and effectiveness of daptomycin in children, but it seems to be promising antimicrobial agent in pediatric patients.

Characterization of Acinetobacter baumannii from intensive care units and home care patients in Palermo, Italy.

In this study 45 isolates of Acinetobacter baumannii identified from patients in intensive care units of three different hospitals and from pressure ulcers in home care patients in Palermo, Italy, during a 3-month period in 2010, were characterized. All isolates were resistant to at least three classes of antibiotics, but susceptible to colistin and tygecycline. Forty isolates were non-susceptible to carbapenems. Eighteen and two isolates, respectively, carried the bla(OXA-23-like) and the bla(OXA-58-like) genes. One strain carried the VIM-4 gene. Six major rep-PCR subtype clusters were defined, including isolates from different hospitals or home care patients. The sequence type/pulsed field gel electrophoresis group ST2/A included 33 isolates, and ST78/B the remaining 12. ST2 clone proved to be predominant, but a frequent involvement of the ST78 clone was evident.