Containment of an outbreak of KPC-3-producing Klebsiella pneumoniae in Italy

The high incidence of carbapenem-resistant Klebsiella pneumoniae in urine from elderly hospital patients may facilitate the spread of resistant strains to the community

Almost all European countries are affected by the expansion of carbapenem-resistant Enterobacteriaceae occurring during recent years. In the two hospitals of Verona, Italy, the incidence of carbapenem-nonsusceptible Klebsiella pneumoniae (CNSKP) began to increase by the first months of 2011, reached a peak in the summer of the same year, and currently is around 30%. Contrary to what was reported by other hospitals and although significant percentages of CNSKP were detected in respiratory samples, blood and pus, urine from hospitalized patients, mainly geriatrics, are the clinical samples with the highest incidence of these strains. Elder patients are frequently transferred from the hospital to their own homes or long-term care facilities and vice-versa. Moreover, urinary tract infections are not considered as a severe pathology and frequently is asymptomatic in elderly. For these reasons, the presence of carbapenem non-susceptible bacteria in the urinary tract of geriatric patients might be an underestimated cause of multiresistant strain spreading to the non-hospitalized population and the community.

Carbapenemase-producing Enterobacteriaceae in Europe: a survey among national experts from 39 countries, February 2013

The spread of carbapenemase-producing Enterobacteriaceae (CPE) is a threat to healthcare delivery, although its extent differs substantially from country to country. In February 2013, national experts from 39 European countries were invited to self-assess the current epidemiological situation of CPE in their country. Information about national management of CPE was also reported. The results highlight the urgent need for a coordinated European effort on early diagnosis, active surveillance, and guidance on infection control measures.

KPC - 3 Klebsiella pneumoniae ST258 clone infection in postoperative abdominal surgery patients in an intensive care setting: analysis of a case series of 30 patients

BACKGROUND

Abdominal surgery carries significant morbidity and mortality, which is in turn associated with an enormous use of healthcare resources. We describe the clinical course of 30 Intensive Care Unit (ICU) patients who underwent abdominal surgery and showed severe infections caused by Klebsiella pneumoniae sequence type (ST) 258 producing K. pneumoniae carbapenemase (KPC-Kp). The aim was to evaluate risk factors for mortality and the impact of a combination therapy of colistin plus recommended regimen or higher dosage of tigecycline.

METHODS

A prospective assessment of severe monomicrobial KPC-Kp infections occurring after open abdominal surgery carried out from August 2011 to August 2012 in the same hospital by different surgical teams is presented. Clinical and surgical characteristics, microbiological and surveillance data, factors associated with mortality and treatment regimens were analyzed. A combination regimen of colistin with tigecycline was used. A high dose of tigecycline was administered according to intra-abdominal abscess severity and MICs for tigecycline.

RESULTS

The mean age of the patients was 56.6 ± 15 and their APACHE score on admission averaged 22.72. Twenty out of 30 patients came from the surgical emergency unit. Fifteen patients showed intra-abdominal abscess, eight anastomotic leakage, four surgical site infection (SSI) and three peritonitis. The overall crude ICU mortality rate was 40% (12 out of 30 patients). Twelve of the 30 patients were started on a combination treatment of high-dose tigecycline and intravenous colistin. A significantly lower mortality rate was observed among those patients compared to patients treated with approved dose of tigecycline plus colistin. No adverse events were reported with high doses of tigecycline.

CONCLUSIONS

Critically-ill surgical patients are prone to severe post-surgical infectious complications caused by KPC-Kp. Timely microbiological diagnosis and optimizing antibiotic dosing regimens are essential to prevent worse outcomes. Further studies and well-controlled clinical trials are needed to define the optimal treatment of infections by KPC-Kp and, more generally, carbapenem-resistant bacteria.

Antimicrobial resistance in internal medicine wards

Antimicrobial resistance is a global medical problem, affecting most bacterial pathogens. The major challenges are currently posed by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Enterobacteriaceae producing extended-spectrum-beta-lactamases (ESBL) and carbapenemases, and multi-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii. Therapeutic options are very limited and, in some cases, virtually unavailable. This article provides an overview of the recent epidemiological trends exhibited by the most important multi-resistant pathogens, and of the treatment options that are currently available for these infections.

Rapid evolution and spread of carbapenemases among Enterobacteriaceae in Europe

Plasmid-acquired carbapenemases in Enterobacteriaceae, which were first discovered in Europe in the 1990s, are now increasingly being identified at an alarming rate. Although their hydrolysis spectrum may vary, they hydrolyse most β-lactams, including carbapenems. They are mostly of the KPC, VIM, NDM and OXA-48 types. Their prevalence in Europe as reported in 2011 varies significantly from high (Greece and Italy) to low (Nordic countries). The types of carbapenemase vary among countries, partially depending on the cultural/population exchange relationship between the European countries and the possible reservoirs of each carbapenemase. Carbapenemase producers are mainly identified among Klebsiella pneumoniae and Escherichia coli, and still mostly in hospital settings and rarely in the community. Although important nosocomial outbreaks with carbapenemase-producing Enterobacteriaceae have been extensively reported, many new cases are still related to importation from a foreign country. Rapid identification of colonized or infected patients and screening of carriers is possible, and will probably be effective for prevention of a scenario of endemicity, as now reported for extended-spectrum β-lactamase (mainly CTX-M) producers in all European countries.

Inter-hospital outbreak of Klebsiella pneumoniae producing KPC-2 carbapenemase in Ireland

OBJECTIVES

To describe an outbreak of KPC-2-producing Klebsiella pneumoniae with inter-hospital spread and measures taken to control transmission.

METHODS

Between January and March 2011, 13 K. pneumoniae isolates were collected from nine patients at hospital A and two patients at hospital B. Meropenem, imipenem and ertapenem MICs were determined by Etest, carbapenemase production was confirmed by the modified Hodge method and by a disc synergy test, and confirmed carbapenemase producers were tested for the presence of carbapenemase-encoding genes by PCR. PFGE, plasmid analysis, multilocus variable-number tandem-repeat analysis (MLVA) and multilocus sequence typing (MLST) analysis were performed on all or a subset of isolates.

RESULTS

Meropenem, imipenem and ertapenem MICs were 4 to >32, 8-32 and >16 mg/L, respectively. PCR and sequencing confirmed the presence of bla(KPC-2). PFGE identified four distinguishable (≥88%) pulsed-field profiles (PFPs). Isolates distinguishable by PFGE had identical MLVA profiles, and MLST analysis indicated all isolates belonged to the ST258 clone. Stringent infection prevention and control measures were implemented. Over a period of almost 8 months no further carbapenemase-producing Enterobacteriaceae (CPE) were isolated. However, KPC-2-producing K. pneumoniae was detected in two further patients in hospital A in August (PFP indistinguishable from previous isolates) and October 2011 (PFP similar to but distinguishable from previous isolates).

CONCLUSIONS

Stringent infection prevention and control measures help contain CPE in the healthcare setting; however, in the case of hospital A, where CPE appears to be established in the population served, it may be virtually impossible to achieve eradication or avoid reintroduction into the hospital.

Imported Klebsiella pneumoniae carbapenemase-producing K. pneumoniae clones in a Greek hospital: impact of infection control measures for restraining their dissemination

The recent emergence of carbapenemase-producing Enterobacteriaceae strains represents a major threat for hospitalized patients. We document the dissemination and control of carbapenemase-producing Klebsiella pneumoniae clones in a Greek hospital. During a 3-year study period (January 2009 to December 2011), carbapenemase-producing K. pneumoniae strains were isolated from clinical samples from 73 individual patients. Phenotyping and molecular testing confirmed that 52 patients were infected with K. pneumoniae carbapenemase 2 (KPC-2) producers, 12 were infected with VIM-1 producers, and the remaining 9 were infected with isolates producing both KPC-2 and VIM-1 enzymes. Twenty-eight of these clinical cases were characterized as imported health care associated, and 23 of these were attributed to KPC producers and 5 were attributed to KPC and VIM producers. The remaining 45 cases were deemed hospital acquired. In the second year of the study, intensified infection control intervention was implemented, followed by active surveillance and carrier isolation in the third year. The incidence of carbapenemase-producing K. pneumoniae patient cases decreased from 0.52/1,000 patient days in 2009 to 0.32/1,000 patient days in 2010 (P = 0.075). Following these additional infection control measures, the incidence fell to 0.21/1,000 patient days in 2011 and differed significantly from that in 2009 (P = 0.0028). Despite the fact that the imported cases of carbapenemase-producing K. pneumoniae were equally distributed over this 3-year period, the incidence of hospital-acquired cases decreased from 0.36/1,000 patient days in 2009 to 0.19/1,000 patient days in 2010 (P = 0.058) and to 0.1/1,000 patient days in 2011 (P = 0.0012). Our findings suggest that rigorous infection control measures and active surveillance can effectively reduce the incidence of secondary transmission due to KPC-producing pathogens.

Rapid detection of intestinal carriage of Klebsiella pneumoniae producing KPC carbapenemase during an outbreak

Two different approaches are described for rapid detection of intestinal carriage of Klebsiella pneumoniae producing KPC-type carbapenemase (KPC-KP), based on PCR amplification of DNA extracts from rectal swabs (K-PCR), and on direct plating of rectal swabs on to MacConkey agar with a meropenem disc and a meropenem plus 3-aminophenylboronic acid disc (direct KPC screening test, DKST). K-PCR and DKST were tested with a total of 101 samples from 65 patients, during an outbreak. Although less sensitive, DKST could detect high-level carriage, which appears to be common among infected and colonised patients, while being very cheap and easy to perform, and requiring only basic facilities.

Detection of Pseudomonas aeruginosa isolates of the international clonal complex 11 carrying the blaPER-1 extended-spectrum β-lactamase gene in Greece

OBJECTIVES

The extended-spectrum β-lactamase (ESBL) PER-1 initially disseminated among Pseudomonas aeruginosa strains in Turkey. Despite reports from other European countries, such strains have not been detected in Greece until now. We describe the first bla(PER-1)-positive P. aeruginosa isolates from Greece and their genetic environment.

METHODS

From January 2008 to December 2009, 287 consecutive non-duplicate P. aeruginosa isolates with reduced susceptibility or resistance to ceftazidime (MIC >8 mg/L) were screened for ESBL production with a modified boronic acid-based double-disc synergy test. Phenotypically ESBL-positive isolates were subjected to agar dilution, PFGE and multilocus sequence typing (MLST). Broad-spectrum bla genes were identified by PCR and sequencing. Plasmid analysis and conjugation experiments were performed. The location of the bla(PER-1) gene was detected by Southern blotting and its genetic environment was characterized using inverse PCR.

RESULTS

Five isolates were phenotypically positive for ESBL production, exhibited resistance to cefepime, ceftazidime, aztreonam and meropenem, and carried the bla(PER-1) gene. MLST showed that they belonged to sequence type (ST) 235, which belongs to the international clonal complex 11. Four isolates had the same PFGE pattern. Southern blotting revealed the chromosomal location of the bla(PER-1) gene. Analysis of the bla(PER-1) flanking regions showed identity to transposon Tn1213 downstream and 1406 bp upstream of bla(PER-1). Further upstream, an orfA gene and ISPa12 were identified; both were truncated by the insertion of IS6100.

CONCLUSIONS

This study confirmed the presence of PER-1-producing P. aeruginosa strains in Greece. The chromosomal location of bla(PER-1), as part of a truncated transposon, suggests clonal expansion rather than horizontal gene transfer.