María Pilar Romero-Gómez

Infections caused by OXA-48-producing Klebsiella pneumoniae in a tertiary hospital in Spain in the setting of a prolonged, hospital-wide outbreak

OBJECTIVES We describe clinical and microbiological features of infections caused by OXA-48-producing Klebsiella pneumoniae (O48KP) in the setting of a prolonged, hospital-wide outbreak detected in January 2011. METHODS Clinical, demographic and microbiological data of patients with growth of O48KP in clinical specimens were collected until December 2011. PCR was used to detect carbapenemase and β-lactamase genes. The genetic relationships were determined by automated repetitive-sequence-based PCR. RESULTS Seventy-one patients with clinically guided cultures showing growth of O48KP were identified. Nine were considered to be colonizing rather than causing infection. The most frequent source of infection was the urinary tract (22/62), followed by surgical site infections (17/62). Blood cultures were positive in 23/62 patients. Many patients had significant comorbidity and prolonged hospital stays. In-hospital mortality among patients with O48KP infections was 43.5%. The MIC(90)s of ertapenem, imipenem and meropenem were >32, 16 and 16 mg/L, respectively. No single antimicrobial was active against all the isolates. The antibiotics most active against O48KP were amikacin (97.2% susceptible), colistin (90.1%), tigecycline (73%) and fosfomycin (66.2%). Although eight clones were identified, a predominant clone caused 73.2% of the infections. Multilocus sequence typing (MLST) of the predominant clone gave sequence type (ST) 405 and bla(TEM-1), bla(SHV-76), bla(CTX-M-15) and bla(OXA-1) genes and the insertion sequence IS1999 of the Tn1999 transposon were associated with bla(OXA-48) in this clone. CONCLUSIONS To our knowledge, this is the largest reported series of infections caused by O48KP in the setting of a single-centre outbreak and provides further input on the clinical relevance of infections caused by O48KP and the difficulties associated with its detection and control.

Bacteraemia due to OXA-48-carbapenemase-producing Enterobacteriaceae: a major clinical challenge

Bacteraemia due to carbapenemase-producing Enterobacteriaceae is an emerging medical problem. Management of this entity is complicated by the difficulty in identifying resistance patterns and the limited therapeutic options. A cohort study was performed including all episodes of bloodstream infection due to OXA-48-producing Enterobacteriaceae (O48PE), occurring between July 2010 and April 2012. Data on predisposing factors, clinical presentation, therapy and outcome were collected from medical records. There were 40 cases of bacteraemia caused by O48PE, 35 Klebsiella pneumoniae and five Escherichia coli. Patients were elderly with significant comorbidities (57.5% underlying malignancy). Thirty-five cases (87.5%) were nosocomial, and five (12.5%) were healthcare-associated. Patients had frequently been exposed to antibiotics and to invasive procedures during hospitalization. The most common source of bacteraemia was the urinary tract followed by deep intra-abdominal surgical site infection. Clinical presentation was severe sepsis or shock in 18 cases (45%). Extended-spectrum β-lactamase production was detected in 92.5% of isolates. MIC(90) for ertapenem, imipenem and meropenem were 32, 16 and 16 mg/L, respectively. Most frequently preserved antibiotics were amikacin, colistin, tigecycline and fosfomycin. These antibiotics combined are the basis of targeted therapies, including carbapenem in selected cases. Median delay in starting clinically adequate and microbiologically appropriate treatment was 3 days. Crude mortality during admission and within 30 days from bacteraemia was 65% and 50%, respectively. Bloodstream infections caused by O48PE have a poor prognosis. Delay in diagnosis and in initiation of optimal antimicrobial therapy is frequent. Suspicion and rapid identification could contribute to improving outcomes.

Nosocomial outbreak of linezolid-resistant Enterococcus faecalis infection in a tertiary care hospital

We describe 12 cases of linezolid-resistant Enterococcus faecalis. The present study was done in 2 wards of Hospital Universitario La Paz in Madrid, Spain. The 2 wards involved were the intensive care unit (ICU) and reanimation unit. Twelve clinical strains of E. faecalis reported by the clinical laboratory as linezolid resistant based on MICs determined by E-test (AB Biodisk, Solna, Sweden) were collected between September 2005 and October 2006. The MIC of linezolid for all the resistant isolates was >128 microg/mL. The isolates were analyzed for the presence of the G2576T mutation by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and pyrosequencing. Pyrosequencing showed that the first isolate had G and T at position 2576 in a 1:1 ratio, whereas the remaining ones had a wild type to mutant ratio of 1:3. PCR-RFLP showed that the mutations were in alleles 1, 3, and 4. The 12 isolates under investigation came from different patients but were indistinguishable by pulsed-field gel electrophoresis (n = 7) and repetitive extragenic palindromic sequence (REP)-PCR (n = 12). This is the first report of a clonal outbreak of linezolid-resistant E. faecalis in Spain. To prevent or minimize the emergence of resistance, we should use linezolid strictly after the therapeutic indications, courses of treatment should be kept as short as possible, and risk factors for resistance development should be considered before starting. In addition, we suggest that susceptibility testing of clinically significant Gram-positive pathogens should be done in all cases of treatment failure, and, depending on the local epidemiology of each ICU, it might be advisable to do it before starting treatment with linezolid.

Evaluation of the BinaxNOW PBP2a assay for the direct detection of methicillin resistance in Staphylococcus aureus from positive blood culture bottles

BinaxNOW® PBP2a rapid immunochromatographic assay is a novel test for the identification of methicillin resistance in Staphylococcus aureus from clinical blood culture samples based on detection of penicillin binding protein 2a. We have evaluated the utility of this assay to do a rapid diagnostic of methicillin susceptibility directly from blood culture bottles after identification of S. aureus in positive bottles by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry. Twenty of 21 methicillin-resistant S. aureus (MRSA) samples from blood cultures were positive on direct immunochromatographic testing (sensitivity 95.24%, 95% confidence interval [CI] 74.13% to 99.75%), whereas 37 methicillin-susceptible S. aureus (MSSA) samples were negative (specificity 100%, 95% CI 88.99% to 99.75%). The combined use of MALDI-TOF mass spectrometry and BinaxNOW® PBP2a test is useful for the rapid identification of both MRSA and MSSA from blood cultures.

Mechanisms of linezolid-resistance among staphylococci in a tertiary hospital

ABSTRACT The mechanisms of linezolid resistance among 86 staphylococcal isolates from two intensive care units were investigated. The most frequent was the G2576T mutation in the 23S rRNA (82%). The cfr gene was found in 17% of the isolates, seven S. aureus and eight S. epidermidis isolates. Four of the S. epidermidis isolates had the G2576T mutation and the cfr gene. In four S. haemolyticus isolates, the mechanism could not be identified.

Pandemic H1N1 influenza-associated hospitalizations in children in Madrid, Spain.

Please cite this paper as: del Rosal et al. (2011) Pandemic H1N1 influenza‐associated hospitalizations in children in Madrid, Spain. Influenza and Other Respiratory Viruses 5(6), e544–e551.

Bacteraemia due to meticillin-resistant Staphylococcus aureus carrying the mecC gene in a patient with urothelial carcinoma.

We present a case of bacteraemia due to meticillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene. The susceptibility to meticillin of Staphylococcus aureus was investigated directly from one blood culture bottle using GenomEra MRSA/SA (Abacus Diagnostica Oy) test. This test identified S. aureus but the presence of the mecA gene result was negative, and the isolate was reported as meticillin-sensitive Staphylococcus aureus (MSSA). Susceptibility studies were done using VITEK 2 AST-P588 susceptibility cards (bioMérieux). The strain was identified as MRSA by the VITEK 2 system, although oxacillin MIC was low (0.5 µg ml(-1)). In view of these results, the isolate was tested for the presence of the mecC gene by a specific PCR and was verified as MRSA carrying mecC. The emergence of this new mecA homologue could have important consequences for the detection of MRSA when routine PCR methods are used as an identification method or provisional detection of MRSA, as in the case reported in this article, because S. aureus carrying the mecC gene will be wrongly diagnosed as meticillin susceptible. Negative results must be interpreted with caution and should be followed by conventional culture, and antimicrobial susceptibility testing or detection of mecC gene by a specific PCR.

Community-acquired pneumonia during the first post-pandemic influenza season: A prospective, multicentre cohort study

Summary Objectives To determine the aetiology, clinical features and prognosis of CAP during the first post-pandemic influenza season. We also assessed the factors associated with severe disease and tested the ability of a scoring system for identifying influenza A (H1N1)pdm09-related pneumonia. Methods Prospective cohort study carried out at 10 tertiary hospitals of Spain. All adults hospitalised with CAP from December 01, 2010 to March 31, 2011 were analysed. Results A total of 747 adults with CAP required hospitalisation. The aetiology was determined in 315 (42.2%) patients, in whom 154 (21.9%) were due to bacteria, 125 (16.7%) were due to viruses and 36 (4.8%) were mixed (due to viruses and bacteria). The most frequently isolated bacteria were Streptococccus pneumoniae. Among patients with viral pneumonia, the most common organism identified were influenza A (H1N1)pdm09. Independent factors associated with severe disease were impaired consciousness, septic shock, tachypnea, hyponatremia, hypoxemia, influenza B, and influenza A (H1N1)pdm09. The scoring system evaluated did not differentiate reliably between patients with influenza A (H1N1)pdm09-related pneumonia and those with other aetiologies. Conclusions The frequency of bacterial and viral pneumonia during the first post-pandemic influenza season was similar. The main identified virus was influenza A (H1N1)pdm09, which was associated with severe disease. Although certain presenting clinical features may allow recognition of influenza A (H1N1)pdm09-related pneumonia, it is difficult to express them in a reliable scoring system.

Community-Onset Bloodstream and Other Infections, Caused by Carbapenemase-Producing Enterobacteriaceae: Epidemiological, Microbiological, and Clinical Features.

Background. Because most infections caused by carbapenemase-producing Enterobacteriaceae (CPE) begin during hospitalization, there are limited data about community-onset (CO) infections caused by CPE. Our aim is to describe the frequency of CO infections caused by CPE as well as the clinical features of CO bloodstream infections (CO-BSIs). Methods. This study includes retrospective case series of CO infections caused by CPE in a tertiary hospital from January 2010 to July 2014. Any clinical sample with a positive culture for CPE that had been ordered by primary care doctors or by doctors at the emergency room (ER) were classified as CO. Epidemiological and microbiological features of CO cases were assessed as were clinical features of CO-BSIs. Results. Of 780 clinical samples with CPE, 180 were requested at the ER or by primary care doctors (22.9%), 150 of which were produced by Klebsiella pneumoniae (83.3%). The blaOXA−48 gene was detected in 149 isolates (82.8%) followed by the blaVIM gene, 29 (16.1%). Sixty-one patients (33.9%) had a prior history of CPE infection/colonization. Thirty-four of the 119 (28.6%) patients without prior history of CPE infection/colonization did not fulfill Friedman criteria for healthcare-associated infections (HAIs). Considering previous hospitalization of up to 12 months as a criterion for defining HAI, only 16 (13.4%) cases were identified as community-acquired infections. The most frequent positive sample was urine (133 of 180; 73.9%). Twenty-one (11.7%) patients had a BSI, 9 of them secondary to urinary tract infections (42.9%). Thirty-day crude mortality among patients with BSI was 23.8% (5 of 21). Conclusions. Community-onset infections caused by CPE are an important subgroup of all CPE infections. The urinary tract is the main source. Bloodstream infections accounted for more than 10% of the cases.

Perspectives from Spanish infectious diseases professionals on 2009 A (H1N1) influenza: the third half

The first influenza pandemic in more than 40 years was declared in 2009. We aimed to evaluate the beliefs of Spanish infectious diseases professionals regarding several aspects of 2009 A (H1N1) influenza once the epidemic waned. An online survey was designed and distributed among members of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC). The survey considered hospital organization and preparedness planning and conduct, as well as the opinion of the infectious diseases professionals regarding several key issues. Between 7 March and 22 March 2010, 303 responses, corresponding to 12.8% of the SEIMC membership, were received. Of the respondents, 48.2% were microbiologists and 42.3% were clinicians dealing with infectious diseases. Forty-one per cent of respondents did not believe that 2009 A (H1N1) influenza had a more severe presentation than other seasonal influenzas. Only 5% fully agreed that 2009 A (H1N1) influenza had a more severe presentation. Influenza planning was available in 69.7% of represented institutions before the arrival of 2009 A (H1N1) influenza, and was considered to be useful, to different extents, by most professionals. In most institutions (88.3%), a multidisciplinary team was created to coordinate local pandemic influenza actions. The most successful protocols were those provided by regional healthcare authorities, followed by those from the CDC. The most problematic issues regarding 2009 A (H1N1) influenza were the management of patients in the emergency room and the vaccination and awareness of healthcare professionals (HCPs) regarding infection control. Microbiological diagnosis and the availability of antivirals were the least problematic areas. Although the majority of surveyed infectious diseases professionals did not believe that 2009 A (H1N1) influenza had an especially severe presentation, most of them agreed with the way that this epidemic was managed in their institutions.