Klebsiella pneumoniae KPC: first isolations in Italy

Klebsiella pneumoniae carbapenemase (KPC) was detected in two isolates of carbapenem-resistant K. pneumoniae in an italian teaching hospital. This is the first report of a KPC-producing isolates in our country. The first strain was isolated from a urine sample collected from a indwelling urinary catheter in a ICU-patient with subdural haematoma, while the second was from the culture of the central venous catheter (CVC) in a patient affected by Crohn’s disease admitted in gastroenterology ward. Both were resistant to all ß-lactams, susceptible to imipenem and meropenem and resistant to ertapenem.They were resistant to other classes of non-ß-lactams antibiotics such as quinolones, aminoglycosides (with the exception of amikacin), trimethoprim-sulfamethoxazole (TMP-SMX) as well as to nitrofurantoin.The isolates were not associated with travel abroad.They were found to contain the plasmid encoded carbapenemase gene blaKPC and were also positive to the Hodge’s test.The detection of KPC-producing bacteria has important implications in infection control and public health. The K. pneumoniae carbapenemase (KPC) belong to class A ß-lactamases of the functional group 2f. Reported for the first time in U.S. in 2001, these agents were subsequently identified in Europe. KPC strains are typically resistant to penicillins, extended-spectrum cephalosporin and aztreonam and present a peculiar behavior against carbapenems in that MIC is close to the susceptibility value or is borderline (except for ertapenem).This pattern is often associated with resistance to quinolones.The information is conveyed by the resistance plasmids, thus explaining their diffusion and implication in outbreaks of KPC. Despite this, to date there are few reports concerning the isolation of this phenotype in Italy.The purpose of this paper is to present two clinical cases related to the isolation of KPC in our hospital. The KPC-producing strains have been respectively isolated: the first in a patient with Crohn’s disease, and the second in a patient with a subdural haematoma. Nono of these patient had a recent history of travel abroad. The strains were characterized by Vitek 2 and E-test (bioMérieux). The phenotype was confirmed through the execution of the Hodge’s test and by PCR blaKPC. The genetic relationship between isolates was determined by Rep-PCR. Both isolates were resistant to ß-lactams, quinolones and ertapenem, and were susceptible to imipenem, meropenem, tigecycline and colistin. The Hodge’s test was positive and the sequence analysis of the blaKPC gene revealed a KPC gene type 2. The fingerprinting showed that the isolates were clonally related. Both patients were successfully treated with tigecycline. KPC represents a real challenge either for the clinicians, who have limited therapeutic options to treat infections due to this microorganism, and for the laboratory, since their correct identification is necessary to reduce the dissemination of the pathogen.