Relevance of multidrug-resistant Pseudomonas aeruginosa infections in cystic fibrosis.

Multidrug-resistant (MDR) Pseudomonas aeruginosa is an important issue for physicians who take care of patients with cystic fibrosis (CF). Here, we review the latest research on how P. aeruginosa infection causes lung function to decline and how several factors contribute to the emergence of antibiotic resistance in P. aeruginosa strains and influence the course of the infection course. However, many aspects of the practical management of patients with CF infected with MDR P. aeruginosa are still to be established. Less is known about the exact role of susceptibility testing in clinical strategies for dealing with resistant infections, and there is an urgent need to find a tool to assist in choosing the best therapeutic strategy for MDR P. aeruginosa infection. One current perception is that the selection of antibiotic therapy according to antibiogram results is an important component of the decision-making process, but other patient factors, such as previous infection history and antibiotic courses, also need to be evaluated. On the basis of the known issues and the best current data on respiratory infections caused by MDR P. aeruginosa, this review provides practical suggestions to optimize the diagnostic and therapeutic management of patients with CF who are infected with these pathogens.

Accurate identification of members of the Burkholderia cepacia complex in cystic fibrosis sputum.

UNLABELLED: The Burkholderia cepacia complex (BCC) is a group of closely related species which includes opportunistic pathogens causing chronic respiratory infections in immunocompromised patients, or individuals affected by cystic fibrosis (CF). Other Burkholderia species causing infection in the CF population are Burkholderia gladioli and Burkholderia pseudomallei. Traditional phenotypic analyses have been demonstrated to be inadequate for reliable identifications of isolates of BCC and B. gladioli. A pan-genomic analysis approach was used to design species-specific probes for Burkholderia cenocepacia, B. cepacia, Burkholderia multivorans, Burkholderia vietnamiensis, Burkholderia ambifaria, Burkholderia dolosa, Burkholderia pyrrocinia and B. gladioli. Multiplex real-time PCR assay was developed and tested using sputum specimens collected from CF patients spiked with Burkholderia species. The assay exhibited 100% sensitivity for all eight target species and detected 10(2) to 10(3)  CFU ml(-1) when applied to spiked sputum. Our PCR assay resulted highly specific for each of the Burkholderia species tested, allowing discrimination among Burkholderia and non-Burkholderia pathogens. Analysis carried out on 200 sputa positive for the presence of Burkholderia revealed that PCR assay and recA sequencing were fully comparable for identification of Burkholderia at the level of species. SIGNIFICANCE AND IMPACT OF THE STUDY: Burkholderia cepacia complex (BCC) has a complex taxonomic organization and its identification is a challenge for microbiology laboratories. Nonidentification or misidentification of BCC isolates represent a problem in epidemiology and treatment of cystic fibrosis patients. The high specificity and sensitivity of the multiplex Real-time PCR assay developed in this study indicates its potential to be a rapid and reliable method for the detection of Burkholderia at the level of species from sputum samples of cystic fibrosis patients.

Clonal spread and patient risk factors for acquisition of extensively drug-resistant Acinetobacter baumannii in a neonatal intensive care unit in Italy.

AIM: To report an outbreak of extensively drug-resistant (XDR) Acinetobacter baumannii in the neonatal intensive care unit (NICU) of an Italian university hospital. Patient risk profiles for acquisition of A. baumannii and measures used to control the outbreak are described. METHODS: Antibiotic susceptibility of strains was evaluated by microdilution. Genotyping was performed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing. Carbapenemase genes were analysed by polymerase chain reaction and DNA sequencing. A case-control study was designed to identify risk factors for acquisition of A. baumannii. FINDINGS: A. baumannii was isolated from 22 neonates, six of whom were infected. One major PFGE type was identified, assigned to sequence type (ST) 2, corresponding to International Clone II; this was indistinguishable from isolates from the adult ICU in the same hospital. A. baumannii isolates were resistant to aminoglycosides, quinolones and classes of ß-lactam antibiotics, but were susceptible to tigecycline and colistin. Carbapenem resistance was associated with the presence of transposon Tn2006 carrying the bla(OxA-23) gene. Length of NICU stay, length of exposure to A. baumannii, gestational age, use of invasive devices and length of exposure to invasive devices were significantly associated with acquisition of A. baumannii on univariate analysis, while length of exposure to central venous catheters and assisted ventilation were the only independent risk factors after multi-variate analysis. CONCLUSIONS: This XDR A. baumannii outbreak in an NICU was probably caused by intrahospital transfer of bacteria via a colonized neonate whose mother was admitted to the adult ICU. Strengthened infection control measures were necessary to control the outbreak.

MALDI-TOF mass spectrometry and microsatellite markers to evaluate Candida parapsilosis transmission in neonatal intensive care units.

Recent studies on outbreaks of Candida showed an increased incidence of bloodstream infections in neonatal intensive care units (NICUs) caused by C. parapsilosis species, highlighting the need for the proper identification and epidemiology of these species. Several systems are available for molecular epidemiological and taxonomic studies of fungal infections: pulsed-field gel electrophoresis (PFGE) represents the gold standard for typing, but is also one of the most lengthy and expensive, while simple sequence repeats (SSRs) is based on polymerase chain reaction (PCR) amplification and is, therefore, faster. Only recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used to identify and type microorganisms involved in nosocomial outbreaks. In our study, 19 strains of C. parapsilosis isolated from the blood cultures of neonates admitted to the University Hospital Federico II were genotyped by the amplification of eight SSR markers and by MALDI-TOF MS. Electrophoretic and spectrometric profile results were compared in order to identify similarities among the isolates and to study microevolutionary changes in the C. parapsilosis population. The discriminatory power and the unweighted pair group method with arithmetic mean (UPGMA) dendrograms generated were compared in order to evaluate the correlation of the groups established by the analysis of the clusters by both methods. Both methods were rapid and effective in highlighting identical strains and studying microevolutionary changes in the population. Our study evidenced that mass spectroscopy is a useful technique not only for the identification but also for monitoring the spread of strains, which is critical to control nosocomial infections.

Effect of intragastric volume and osmolality on mechanisms of gastroesophageal reflux in children with gastroesophageal reflux disease.

OBJECTIVE: Both transient lower esophageal sphincter (LES) relaxations (TLESRs) and periods of low/absent LES pressure (LESP) are the main mechanisms of gastroesophageal reflux. These events are believed to be triggered by stimuli from different areas of the upper GI tract. We aimed at investigating the relationship between LESP profile and gastric emptying and distension after meals of different composition in 30 children with gastroesophageal reflux disease (median age 7.0 yr, range 12 months-12 yr). METHODS: Recordings of LESP and intraesophageal pH for 1 h fasting and for 2 postprandial h were performed with a perfused sleeve catheter and flexible electrode, respectively; gastric emptying and distension of antral area were simultaneously recorded with real-time ultrasonography. Ten patients had a standard meal (group A), 10 had a high-volume meal (group B), and 10 had a high-volume and osmolality meal (group C). RESULTS: Postprandial esophageal acid exposure was significantly higher in patients of groups B and C than in patients of group A (p < 0.01); it was also more prolonged in patients of group C than in subjects of group B (p < 0.05). A higher postfeeding rate of reflux episodes caused by TLESRs was detected in patients of groups B and C as compared with patients of group A (p < 0.01). This increase did not statistically differ in patients of groups B and C. Patients of group C exhibited a higher postprandial rate of reflux episodes associated with low/absent tone of the LES as well as a more prolonged gastric emptying time and a higher postfeeding gastric distension as compared with patients of groups A and B (p < 0.01). Finally, a significant correlation was only found between the postprandial rate of reflux events resulting from low/absent LESP and the degree of antral distension in patients of group C (p < 0.01). CONCLUSION: Gastroesophageal reflux is worsened by increasing the volume and osmolality of meals through significant changes of LESP. Meals of high volume and meals with high volume and osmolality cause a comparable increase of reflux episodes as a result of TLESRs. However, meals with high volume and osmolality cause the higher degrees of esophageal acid exposure than meals with high volume resulting from a higher rate of reflux episodes associated with low/absent LESP. This finding correlates with a high postfeeding antral distension.

A normal gastrointestinal motility excludes chronic intestinal pseudoobstruction in children.

Gastrointestinal manometry has gained wide acceptance in the approach to patients with suspected enteric neuromuscular disorders. However, performing gastrointestinal manometry in these subjects without a previous exhaustive diagnostic evaluation is unjustified. Twelve children (median age: 7.0 years; range: 8 months-13 years), with clinical and x-ray features suggesting chronic intestinal pseudoobstruction, were referred to our unit for gastrointestinal manometry. The latter was performed with a perfused catheter for 5 hr in the fasting state and for 90 min after feeding. Data were compared with those recorded in eight age-matched controls. In all patients and controls, interdigestive motor complexes with propagated phases III were detected; a regular postprandial antroduodenal motor activity was also recorded. Patients and controls did not differ for fed antral and duodenal motility indexes, fed antroduodenal coordination, and length of duodenal phase III. Most of the patients showed short or prolonged bursts of nonpropagated activity in the fasting and/or fed states; in four cases fasting and/or fed sustained phasic activity was recorded. Manometric evidence of migrating motor complexes and postfeeding activity did not support the diagnosis of intestinal pseudoobstruction and suggested redirecting the diagnostic evaluation. Final diagnoses were: Munchausen syndrome-by-proxy (four cases), celiac disease (two cases), intestinal malrotation (two cases), Crohn's disease (two cases), multiple food intolerance (one case), and congenital chloride-losing diarrhea (one case). It is concluded that in children with suspected chronic intestinal pseudoobstruction manometric evidence of migrating motor complexes and fed motor activity excludes an enteric neuromuscular disorder and suggests a reassessment of the diagnostic work-up. Furthermore, if gastrointestinal manometry shows migrating motor complexes and postfeeding motor activity, qualitative abnormalities of the manometric tracings do not indicate an underlying enteric neuromuscular disorder and must not be overemphasized. Patients referred for gastrointestinal manometry should previously undergo an extensive diagnostic investigation to exclude disorders mimicking chronic intestinal pseudoobstruction.

Lansoprazole in the treatment of gastro-oesophageal reflux disease in childhood.

BACKGROUND: Acid suppressive therapy is the mainstay of pharmacologic treatment of gastro-oesophageal reflux disease. Use of proton pump inhibitors in children is still limited and has only included omeprazole in a few controlled studies. AIM: To determine efficacy of lansoprazole, a relatively new proton pump inhibitor, on symptoms and oesophagitis in a group of children with gastro-oesophageal reflux disease refractory to H2 receptor antagonists. The required dose of the drug for inhibiting gastric acidity was also determined. PATIENTS AND METHODS: A series of 35 children (median age: 7.6 years, range: 3-15) with oesophagitis refractory to H2 receptor antagonists received a 12-week therapeutic course with lansoprazole. Prior to the study children underwent symptomatic and endoscopic assessment, oesophageal manometry and 24-hour intragastric and intra-oesophageal pH test. The latter was repeated after one week of therapy while patients were on treatment in order to monitor the degree of acid suppression and adjust the dose of the drug. Symptomatic assessment and endoscopy were repeated at the end of the trial RESULTS AND CONCLUSIONS: In 12 patients (group A), the initial dose of the drug was efficacious (1.3 to 1.5 mg/kg/day), whereas in 23 [group B) the initial dose (0.8 to 1.0 mg/kg/day) was increased by half because of insufficient inhibition of intragastric acidity (i.e., when the intra-gastric pH remained below 4.0 for more than 50% of the recording time). Nine patients in group A (75%) and 8 in group B (53.5%) healed (chi2: 3.6, p<0.05); 1 patient in group A [8.3%) and 7 in group B (30.5%) remained unchanged (chi2: 6.9, p<0.01); 2 patients in group A and 8 in group B improved and underwent a further month of therapy. The two groups did not differ as far as concerns baseline pH, endoscopic and clinical variables. In both groups, those patients failing to respond at the end of the trial showed a more impaired oesophageal motility than improved or healed patients. The drug was well tolerated and no significant laboratory abnormalities occurred. In children with gastro-oesophageal reflux disease refractory to H2 receptor antagonists, a 12-week course of lansoprazole is effective both in healing oesophagitis and improving symptoms. An initial dose of 1.5 mg/kg/day of the drug is suggested. However, if during treatment, patients remain symptomatic the dose should be increased and a prolonged intra-gastric and intra-oesophageal pH test performed to evaluate the acid suppression efficacy of the adjusted dose. A short course of lansoprazole appears to be safe and well tolerated in paediatric age.

Colonoscopy and technetium-99m white cell scan in children with suspected inflammatory bowel disease.

OBJECTIVES: To determine the utility of the technetium-labeled autologous white cell scintigraphy (Tc-WCS) for detecting intestinal inflammation in children with suspected inflammatory bowel disease (IBD). Tc-WCS was compared with colonoscopy and histologic examination. STUDY DESIGN: Forty-eight children (26 boys; median age, 10 years; range, 2-17 years) with symptoms and signs suggesting IBD had colonoscopy with exploration of terminal ileum and mucosal biopsies. The scans were judged to be abnormal if activity was seen in the gut within the first hour. RESULTS: Twenty-one patients had a diagnosis of IBD (Crohn's disease, 13; ulcerative colitis, 5; indeterminate colitis, 3); results of scintigraphy were positive in 16 and negative in 5 (sensitivity, 76.2%); the latter had a moderate degree of intestinal inflammation. In 27 patients, IBD was ruled out. Results of scintigraphy were negative in children with non-specific colitis and in those with lymphoid hyperplasia of the terminal ileum, whereas results were positive in 6 of 12 patients with spondyloarthropathy. In children with IBD, there was a significant correlation between results of scintigraphy and endoscopy for the intensity of inflammation (r = 0.70); however, there was a poor correlation regarding the number of involved segments (r = 0.30) because in 16 patients, endoscopy revealed additional diseased segments as compared with scintigraphy. CONCLUSIONS: A positive Tc-WCS result indicates the presence of an inflammatory process of the gut, whereas a negative test result does not rule out intestinal inflammation, especially when the latter is of moderate degree. Colonoscopy and biopsy are the investigations of choice to establish the diagnosis of IBD and are superior to Tc-WCS in assessing topographic extension of IBD.

Gastric emptying delay and gastric electrical derangement in IDDM.

OBJECTIVE: Patients with diabetes can develop gastrointestinal motor complications; however, prevalence of gut dysmotility in children with diabetes is poorly understood. We measured gastric emptying time and gastric electrical activity in children with IDDM; presence of dyspeptic symptoms was also assessed. RESEARCH DESIGN AND METHODS: Gastric emptying time and gastric electrical activity were measured by ultrasonography and electrogastrography (EGG), respectively, in 40 consecutive IDDM children (median age: 9 years [6-14]) without autonomic neuropathy; 15 healthy children (median age: 7 years [4-15]) served as control subjects. The EGG variables studied were percent of electrical dysrhythmias (bradygastria or 0.5-2.0 cpm, tachygastria or 4.0-9.0 cpm; normal rhythm is 2.0-4.0 cpm) and fed-to-fasting ratio of the dominant EGG power. Blood glucose level in the fasting state and 180 min after feeding and HbA1C concentration were also measured. Data are given as median (ranges) and means +/- SD. Statistical analysis was performed using the parametric t test and the nonparametric signed-rank tests, with P < 0.05 considered significant. RESULTS: Gastric emptying time was delayed in 26 patients (group A), whereas in 14 patients (group B), it was in the same range as control values; group A patients significantly differed from group B for increased prevalence of gastric electrical dysrhythmias (P < 0.01) and for a lower fed-to-fasting ratio of the dominant EGG power (P < 0.01). Group B patients did not differ from control subjects for the EGG variables measured. Diabetic children with gastroparesis had significantly higher levels of both HbA1C and blood glucose measured 180 min after feeding than those with normal gastric emptying time (P < 0.05); there was a significant correlation between levels of HbA1C and degree of gastric emptying delay, whereas a significant inverse correlation between gastric emptying time and fed-to-fasting ratio of the dominant EGG power was found both in patients and control subjects. CONCLUSIONS: Delay of gastric emptying time and gastric electrical abnormalities are found in a high proportion of children with diabetes and can contribute to poor glycemic control, most likely by causing a mismatch between the onset of insulin action and the delivery of nutrients into the small intestine. Diabetic children with unexplained poor glycemic control should be investigated for abnormalities in gastric motility.