Eradication of an extensive outbreak in a neonatal unit caused by two sequential Klebsiella pneumoniae clones harbouring related plasmids encoding an extended-spectrum beta-lactamase

Outbreaks caused by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae are difficult to control and closure of an affected unit is sometimes necessary. We describe an outbreak of ESBL-producing K. pneumoniae in a 28-bed neonatal unit that began in August 2005 and lasted for seven months. Weekly rectal swabs were taken from all babies admitted throughout the study period. Review of all procedures, contact precautions, thorough environmental cleaning and restriction of cephalosporin use were implemented. ESBL production was investigated according to CLSI recommendations, and characterised by isoelectric focusing and sequencing. Typing of isolates was assessed by pulsed-field gel electrophoresis. Plasmids were also studied. During the outbreak, 32% of 503 admitted babies became colonised and nine babies developed bacteraemia; all the babies recovered. The outbreak was finally terminated in February 2006. Two distinct clones were observed, the first circulating between August and October 2005, and the second between October 2005 and February 2006. Both of these clones carried the non-ESBL SHV-11 and TEM-4 ESBL. Plasmids harbouring TEM-4 from both clones were similar and molecular analysis suggested horizontal dissemination of a single plasmid between the two clones.

Comparative assessment of inoculum effects on the antimicrobial activity of amoxycillin-clavulanate and piperacillin-tazobactam with extended-spectrum beta-lactamase-producing and extended-spectrum beta-lactamase-non-producing Escherichia coli isolates

A significant inoculum-size effect has been observed with piperacillin-tazobactam, and has been associated with beta-lactamase production in extended-spectrum beta-lactamase (ESBL) producers. This association has not been previously studied in the case of amoxycillin-clavulanate. Piperacillin-tazobactam and amoxycillin-clavulanate were compared, using high inocula of susceptible strains either harbouring ESBLs or not. Two non-ESBL-producing and 15 amoxycillin-clavulanate-susceptible and piperacillin-tazobactam-susceptible ESBL-producing Escherichia coli isolates, and their respective transconjugants, were tested in dilution susceptibility tests using standard and 100-fold higher inocula. Three ESBL-producing strains and E. coli ATCC 25922 were selected for time-kill studies using standard and high initial inocula. At high inocula, MICs of piperacillin increased >eight-fold for non-ESBL-producing strains, and MICs of piperacillin-tazobactam (8:1 ratio or with tazobactam fixed at 4 mg/L) increased>eight-fold for all ESBL-producing strains. However, amoxycillin MICs were not affected by a high inoculum with non-ESBL-producing strains, whereas the MICs of amoxycillin-clavulanate (2:1 and 4:1) increased <or=four-fold for ESBL producers, using the broth and agar dilution methods. In kinetic studies at a high inoculum, amoxycillin and amoxycillin-clavulanate were bactericidal against E. coli ATCC 25922, whereas piperacillin and piperacillin-tazobactam yielded decreases of <1 log(10) CFU/mL. Similarly, at a high inoculum, only amoxycillin-clavulanate was able to maintain bactericidal rates of killing over 24 h against the ESBL-positive E. coli isolates. The stability of amoxycillin-clavulanate and the contrasting results obtained with piperacillin-tazobactam against high inocula of ESBL-non-producing and ESBL-producing E. coli strains appear to be related to aspects other than the amount of beta-lactamase production.

[Cranial lesions due to forceps delivery]

Deliveries with forceps or vacuum-extraction increase the incidence of perinatal craneoencephalic lesions, for which reason cesarean sections are performed more frequently. We report 3 cases of cranial lesions due to forceps deliveries, 2 with depressed skull fractures and 1 with a depressed fracture and an associated epidural hematoma. Diagnosis is made on clinical and radiological founds with CT scan or MRI. Treatment is surgical and consists of elevation of the depressed fracture and evacuation of the hematoma. The correct use of forceps is very important to avoid this kind of lesions in the newborn, especially in cases of difficult delivery.

Carotid body oxygen sensing

The carotid body (CB) is a neural crest-derived organ whose major function is to sense changes in arterial oxygen tension to elicit hyperventilation in hypoxia. The CB is composed of clusters of neuron-like glomus, or type-I, cells enveloped by glia-like sustentacular, or type-II, cells. Responsiveness of CB to acute hypoxia relies on the inhibition of O(2)-sensitive K(+) channels in glomus cells, which leads to cell depolarisation, Ca(2+) entry and release of transmitters that activate afferent nerve fibres. Although this model of O(2) sensing is generally accepted, the molecular mechanisms underlying K(+) channel modulation by O(2) tension are unknown. Among the putative hypoxia-sensing mechanisms there are: the production of oxygen radicals, either in mitochondria or reduced nicotinamide adenine dinucleotide phosphate oxidases; metabolic mitochondrial inhibition and decrease of intracellular ATP; disruption of the prolylhydroxylase/hypoxia inducible factor pathway; or decrease of carbon monoxide production by haemoxygenase-2. In chronic hypoxia, the CB grows with increasing glomus cell number. The current authors have identified, in the CB, neural stem cells, which can differentiate into glomus cells. Cell fate experiments suggest that the CB progenitors are the glia-like sustentacular cells. The CB appears to be involved in the pathophysiology of several prevalent human diseases.

[Childhood spinal tumours]

We report a large series of 48 childhood spine tumors diagnosed and treated at our Hospital between 1986 and 2006. Spinal tumors in children are a rare and heterogeneous condition that frequently are diagnosed late because of their uncharacteristic clinical picture. Symptoms are usually limited to diffuse back pain or spinal deformities, prior to leg paresis or sphincter dysfunction. Diagnosis is usually made with MRI or CT. Treatment is surgical in most cases. The prognosis is variable due to the diverse histological findings and it may require the use of complementary treatments as chemotherapy or radiation.

[Brain-stem tumors in children]

We report a large series of brain-stem tumors seen during 18 years of at our hospital. We diagnosed and treated a total of 42 patients between 1988 and 2006; 36 of them were operated with partial resection in most cases. Brain-stem tumors constitute a rare condition with very bad prognosis. A surgical complete resection of the mass is not possible in most cases, so the principal surgical objective is reduction and decompression. The best prognosis is seen in patients with low grade tumors with minimal neurologic deficit. Most of these tumors cause death in a short period, usually one year or less.

Haemoglobinopathies with high oxygen affinity. Experience of Erythropathology Cooperative Spanish Group

Haemoglobinopathies are the world's most frequently found monogenic disorders. In the cases with high oxygen affinity, the decrease in the liberation of the oxygen determines a secondary erythrocytosis. In this work, we present 17 unrelated families of Caucasian race and of Spanish origin, with ten variants of haemoglobin or haemoglobinopathies with high oxygen affinity which were diagnosed in our laboratory. Of the ten haemoglobinopathies, in four (the Hb San Diego, the Hb Johnstown, the Hb Malmö and the Hb Columbia-Missouri), the change of amino acid affects zones of the contact alpha(1)beta(2); in two variants (the Hb Strasbourg and the Hb Syracuse), it affects the unions with 2,3-DPG in the central cavity; in the other two (the Hb Badalona and the Hb La Coruña), the cavity of contact with the group haem is affected; in one (Hb Bethesda), it affects the zone of contact alpha(1)beta(1;) and in one (Hb Olympia), the position 20 of the chain in the helix B in the surface of the protein is affected. In all cases, the change of amino acid, though of different form, facilitates that the quaternary structure of the haemoglobin becomes stable in its relaxed configuration so the transfer of oxygen and the P(50) value are decreased. All cases were sent to our laboratory because of shown erythrocytosis. In the majority of them, the diagnosis was done during an analysis of routine or for being relatives of the first ones.

Incidence of anaemia and impact on sustained virological response in HIV/HCV-coinfected patients treated with pegylated interferon plus ribavirin

Ribavirin (RBV) exposure is important for maximizing the response to chronic hepatitis C virus (HCV) therapy. However, RBV-associated haemolytic anaemia may force dose reductions or even treatment discontinuation. The use of zidovudine might further increases the risk of anaemia in HCV/HIV-coinfected patients. The predictors of anaemia were examined in PRESCO, a large trial conducted in HIV/HCV-coinfected patients treated with pegylated interferon alpha-2a 180 mug/week plus RBV 1000-1200 mg/day. Measurements included maximal decrease in haemoglobin (Hb) throughout treatment, drops in Hb to <10 (moderate) or to <8.5 g/dL (severe), and premature RBV discontinuation because of anaemia. Finally, the impact of anaemia on sustained virological response (SVR) was assessed. Moderate or severe anaemia occurred, respectively, in 51 (13%) and 13 (3.3%) of 389 patients included in the study. Lower baseline Hb [RR: 0.14 (95% CI 0.07-0.27); P < 0.0001] and greater Hb drops during the first 4 weeks of therapy [RR: 4.74 (95% CI 2.95-7.60); P < 0.0001] were independent predictors of moderate anaemia at any time point in the multivariate analysis. Mean drops in Hb from baseline to week 4 were significantly greater in patients receiving zidovudine compared with other drugs (-3.09 vs-2.3 g/dL; P < 0.001). Lower baseline Hb [RR: 0.33 (95% CI 0.11-0.95); P = 0.04] and maximal Hb drops during treatment [RR: 2.48 (95% CI 1.33-4.59); P = 0.004] predicted treatment discontinuation because of anaemia. However, maximal Hb drops, development of moderate-severe anaemia and RBV dose reductions were comparable among patients who achieved SVR and those who did not. Lower baseline Hb predicts maximal drops in Hb and development of anaemia in HIV/HCV-coinfected patients treated with pegylated interferon plus RBV. The use of zidovudine is associated with greater Hb declines at week 4. However, severe anaemia is relatively infrequent and seems not to have much impact on SVR. Given the availability of alternative antiretroviral drugs, it is advised to avoid zidovudine while receiving anti-HCV treatment.

[Valuation of APRI and Forns models for non-invasive diagnosis of fibrosis in patients with hepatitis C in coinfected and non-coinfected with HIV]

BACKGROUND

APRI and Forns (IF) index are noninvasive models consisting of routine laboratory data for the prediction of liver fibrosis in patients with chronic hepatitis C. The aim of our study was to confirm the value of these models to predict significant fibrosis in these patients and if they may decrease the need for performing liver biopsy specimens in coinfected and HIVnon-coinfected.

PATIENTS AND METHOD

We included 60 patients with chronic hepatitis C and histologic data, 33 were coinfected with HIV. Mild fibrosis (F0-F1) was found in 73% patients, severe fibrosis (F3-F4) in 23% and cirrhosis in 18.3%. We calculated and compared APRI and IF with the stage of liver fibrosis.

RESULTS

The APRI score < 0.5 or > 1.5 and IF < 4.2 or > 6.9, as predictors of mild or severe fibrosis, were only available in 53% and 49%. Neither laboratory nor APRI and IF were associated with liver fibrosis in non-coinfected patients. We only found association in HIV coinfected patients: severe fibrosis (F3-4) whit higher gammaglobulins [24.5% vs. 30% (p < 0.05)] and Gamma-GT levels [77 (46.5) vs. 32 (48.5) (p < 0.05)], and lower prothrombin time [72% vs. 91% (p < 0.05) ] and platelets.109 count [129 (40) vs. 170 (78) (p < 0.05)]; APRI was lower than 0.5 in 41.6% patients with mild fibrosis (F0-1) against none with severe (F3-4) (p < 0.05); specifity (E) of APRI < 0.5 for predicting mild fibrosis was 100%, but sensivity (S) was very low (41%), with a positive preditive value (VPP) of 100%, but a negative predictive value (VPN) also very low ( 36.3%).

CONCLUSIONS

Our study showed that these models don t avoid the need for liver biopsies. More than a half of patients are not appropriately classified according to findings on liver biopsy and S and VPN are very low. The combination of these index with gammaglobulins, Gamma-GT, AST, ALT and platelet levels and protrombine time, only may be an approach to degree of fibrosis or inflammation liver in HIV co-infected patients.