First report of colistin-resistant KPC-2 producing ST258-Klebsiella pneumoniae in Spain

Dear Sir,

The rapid spread of Klebsiella pneumoniae carbapenemases (KPCs) in the last years represents a serious public health threat. KPCs have a great potential for spread due to their location on mobile genetic elements that are horizontally transferred and associated with widespread clones.¹ Many KPC producing K. pneumoniae isolates are associated to a single sequence type (ST)258, a clonal lineage that has been causing epidemics of great proportions in various regions of USA, Israel, Greece and recently in other European countries.^2,3 Organisms carrying carbapenemases usually harbours resistance determinants to other antimicrobials and consequently infections due to these pathogens are difficult to treat which results in high associated morbidity.^4,5

We describe the first KPC-producing K. pneumoniae isolate ST258 identified in Spain. Isolate was recovered in a 59-year-old man previously hospitalized in an intensive care unit (ICU) of a Greek hospital in Athens (December, 2010–March, 2011) for an acute and severe pancreatitis. Patient underwent different surgical procedures as he had numerous necrotic abdominal areas. The transverse colon was found severely ischemic and an extended right colostomy with terminal ileostomy was performed, with a traumatic splenectomy. The descending colon was clipped and left in place. On March 2011, the patient was discharged from the ICU with an abdominal draining catheter due to an abscess in the left abdomen. The abscess still remained and drained when the patient was discharged from the hospital on May 2011 and decided to travel to Spain. Patient's clinical history mentioned that microbiological cultures were positive for Klebsiella spp., but did not specify about antibiotic susceptibility, carbapenemase production or antibiotic treatment. On July 2011, the patient visited for first time the surgery unit of Arnau de Vilanova Hospital, Valencia, Spain, for a reconstructive surgery. Radiological exams revealed the presence of an abdominal collection which exudate drained through an orifice secondary to a pancreatic fistula. Draining catheter was removed leaving a fistula in the abdominal left side. Exudate obtained though catheter was cultivated and Pseudomonas aeruginosa and Enterococcus faecalis were isolated. The patient went home and was orally treated with amoxicillin-clavulanate (1000/62.5 mg) and ciprofloxacin (500 mg) every 12 h for 10 days. Wound was cleaned regularly and seemed to recover. The patient visited regularly the surgery unit of the hospital, but on February 2012 he was admitted in the emergency room for an affluent diarrhea and vomiting requiring admission in the ICU. A multiresistant Klebsiella oxytoca was isolated from the abdominal left side fistula and a multiresistant K. pneumoniae from feces collected from the ileostomy bag and from a rectal swab culture. No other microorganisms associated with gastrointestinal infections were isolated from feces.

Both Klebsiella isolates were resistant to almost all β-lactams tested (Table 1). MICs were interpreted according to clinical breakpoints from the Clinical Laboratory Standards Institute (CLSI).⁶K. pneumoniae isolate was also resistant to tobramycin, amikacin and colistin and showed intermediate susceptibility to tigecycline (MIC = 2 mg/L), whereas K. oxytoca retained susceptibility to these antimicrobial drugs. Isolates demonstrated resistance to ciprofloxacin but were susceptible to gentamicin. Carbapenemase activity was confirmed by the modified Hodge test.⁶ Synergy was detected when meropenem was combined with boronic acid, while there was not synergy with cloxacillin and dipicolinic acid,⁷ suggesting the production of a KPC enzyme. Characterization of carbapenemases showed the presence of KPC-2 enzyme in K. oxytoca and K. pneumoniae isolates.⁸ Detection of extended-spectrum β-lactamases by multiplex PCR assay was negative for both isolates. No further studies were performed to investigate the presence of other betalactamases and loss of porines which could be involved in the high resistance of the isolates. No additional studies were performed to examine mechanisms of resistance for other antimicrobial drugs. Multilocus sequence typing (MLST) results revealed that the K. pneumoniae isolate belonged to the ST258 clone.⁹

Table 1.

Antibiotic susceptibilities (MICs, mg/L) of K. oxytoca and K. pneumoniae isolates harbouring KPCs.

Antibiotic	K. oxytoca	K. pneumoniae
Ampicillin	>16	>16
Amoxicillin-clavulanate	>16/8	>16/8
Piperacillin-tazobactam	>64	>64
Cefalotin	>16	>16
Cefazolin	>16	>16
Cefoxitin	>16	>16
Cefuroxime	>16	>16
Cefotaxime	8	>32
Ceftazidime	16	>16
Cefepime	8	>16
Aztreonam	>16	>16
Imipenem	8	>8
Meropenem	4	12
Ertapenem	>4	>4
Amikacin	≤8	>32
Gentamicin	≤2	4
Tobramicin	≤2	>8
Ciprofloxacin	>2	>2
Tigecycline	0.5	2
Colistin	0.175	128

MICs were performed using the automated WalkAway^® plus system (Siemens Healthcare Diagnostics Ltd., UK) with a NC53 panel. Meropenem, tigecycline and colistin MICs were determined by Etest (BioMérieux, Marcy l’Etoile, France).

Infection control measures consisting of contact precautions were implanted after phenotypic detection of a carbapenemase producing isolate. After rectal swabs culture, none of the patients admitted in the ICU were demonstrated to be colonized with Enterobacteriaceae harbouring KPC enzymes. The patient was treated with linezolid 600 mg IV every 12 h and meropenem 1000 mg IV every 8 h during 7 days and until discharge from the ICU. The patient had no complications and recovered rapidly.

Several reports of KPCs have been described in our country in other members of the Enterobacteriaceae family including K. pneumoniae,^8,10 but none of these isolates proceed from patients transferred from endemic KPCs countries or those who had travelled to these areas. Moreover, they did not belong to the sequence type ST258 K. pneumoniae clone. K. oxytoca producing KPC-2 has a similar susceptibility profile when compared with isolates with KPCs circulating in Spain, showing susceptibility to gentamicin, tobramycin, amikacin, colistin and tigecycline. On the contrary, ST258-K. pneumoniae KPC-2 is resistant to colistin and demonstrates intermediate susceptibility to tigecycline. This susceptibility profile resembles KPC-2 and KPC-3 producers ST258 from USA and European countries where there is a serious endemic situation.^2,3

The emergence of imported KPCs enzymes is extremely worrisome due to the high mortality rates associated with invasive infections caused by organism with these types of enzymes and the limited therapeutic options to treat patients. Rapid detection of KPC-carrying microorganisms with phenotypic and confirmatory molecular tests is essential to establish therapeutic options and infection control measures.⁵ In our case, both clinical and surveillance cultures allow detection of the presence of a multi-resistant KPC-2 producing ST258 K. pneumoniae high-risk clone with rapid implementation of epidemiological control measures.

Funding

This study was partially founded by research grants from Microbial Science Foundation and the European Commission (FP7-HEALTH-2010-282512).

Acknowledgments

AV has a postdoctoral contract “Juan de la Cierva” from the Ministerio de Economía y Competitividad of Spain.