Unique epidemiology of nosocomial urinary tract infection in children

Genomic and metabolic versatility of Pseudomonas aeruginosa contributes to its inter-kingdom transmission and survival

Pseudomonas aeruginosa is one of the most versatile bacteria with renowned pathogenicity and extensive drug resistance. The diverse habitats of this bacterium include fresh, saline and drainage waters, soil, moist surfaces, taps, showerheads, pipelines, medical implants, nematodes, insects, plants, animals, birds and humans. The arsenal of virulence factors produced by P. aeruginosa includes pyocyanin, rhamnolipids, siderophores, lytic enzymes, toxins and polysaccharides. All these virulent elements coupled with intrinsic, adaptive and acquired antibiotic resistance facilitate persistent colonization and lethal infections in different hosts. To date, treating pulmonary diseases remains complicated due to the chronic secondary infections triggered by hospital-acquired P. aeruginosa. On the contrary, this bacterium can improve plant growth by suppressing phytopathogens and insects. Notably, P. aeruginosa is one of the very few bacteria capable of trans-kingdom transmission and infection. Transfer of P. aeruginosa strains from plant materials to hospital wards, animals to humans, and humans to their pets occurs relatively often. Recently, we have identified that plant-associated P. aeruginosa strains could be pathologically similar to clinical isolates. In this review, we have highlighted the genomic and metabolic factors that facilitate the dominance of P. aeruginosa across different biological kingdoms and the varying roles of this bacterium in plant and human health.

Immersion of debrided diabetic foot ulcer (DFU) tissue in electrochemically generated pH neutral hypochlorous acid significantly reduces the microbial bioburden: whole-genome sequencing of Staphylococcus aureus, the most prevalent species recovered

BACKGROUND

Diabetic foot ulcer infections (DFUIs) are the leading cause of lower limb amputations, mediated predominantly by Staphylococcus aureus. pH neutral electrochemically-generated hypochlorous acid (anolyte) is a non-toxic, microbiocidal agent with significant potential for wound disinfection.

AIMS

To investigate both the effectiveness of anolyte for microbial bioburden reduction in debrided ulcer tissues and the population of resident S. aureus.

METHODS

Fifty-one debrided tissues from 30 people with type II diabetes were aliquoted by wet weight and immersed in 1 or 10 ml volumes of anolyte (200 parts per million) or saline for three min. Microbial loads recovered were determined in colony forming units/g (CFU/g) of tissue following aerobic, anaerobic and staphylococcal-selective culture. Bacterial species were identified and 50 S. aureus isolates from 30 tissues underwent whole-genome sequencing (WGS).

FINDINGS

The ulcers were predominantly superficial, lacking signs of infection (39/51, 76.5%). Of the 42/51 saline-treated tissues yielding ≥10⁵ CFU/g, a microbial threshold reported to impede wound-healing, only 4/42 (9.5%) were clinically-diagnosed DFUIs. Microbial loads from anolyte-treated tissues were significantly lower than saline-treated tissues using 1 ml (1065-fold, 2.0 log) and 10 ml (8216-fold, 2.1 log) immersion volumes (p<0.0005). Staphylococcus aureus was the predominant species recovered (44/51, 86.3%) and 50 isolates underwent WGS. All were meticillin-susceptible and comprised 12 sequence types (STs), predominantly ST1, ST5 and ST15. Whole-genome multilocus sequence typing identified three clusters of closely related isolates from 10 patients indicating inter-patient transmission.

CONCLUSIONS

Short immersions of debrided ulcer tissue in anolyte significantly reduced microbial bioburden: a potential novel DFUI treatment.

Whole-genome sequencing analysis of Klebsiella aerogenes among men who have sex with men in Guangzhou, China

Klebsiella aerogenes is a common infectious bacterium that poses a threat to human health. Nevertheless, there are limited data on the population structure, genetic diversity, and pathogenicity of K. aerogenes, especially among men who have sex with men (MSM). The present study aimed to clarify the sequence types (STs), clonal complexes (CCs), resistance genes, and virulence factors of popular strains. Multilocus sequence typing was used to describe the population structure of K. aerogenes. The Virulence Factor Database and Comprehensive Antibiotic Resistance Database were used to assess the virulence and resistance profiles. In this study, next-generation sequencing was performed on nasal swabs specimens collected in an HIV Voluntary Counseling Testing outpatient department in Guangzhou, China, from April to August 2019. The identification results showed that a total of 258 K. aerogenes isolates were collected from 911 participants. We found that the isolates were most resistant to furantoin (89.53%, 231/258) and ampicillin (89.15%, 230/258), followed by imipenem (24.81%, 64/258) and cefotaxime (18.22%, 47/258). The most common STs in carbapenem-resistant K. aerogenes were ST4, ST93, and ST14. The population has at least 14 CCs, including several novel ones identified in this study (CC11-CC16). The main mechanism of drug resistance genes was antibiotic efflux. Based on the presence of the iron carrier production genes irp and ybt, we identified two clusters according to virulence profiles. In cluster A, CC3 and CC4 carry the clb operator encoding the toxin. Increased monitoring is needed for the three main ST type strains carried by MSM. The main clone group CC4 has a large number of toxin genes, and it spreads among MSM. Caution is needed to prevent further spread of this clone group in this population. In sum, our results may provide a foundation for the development of new therapeutic and surveillance strategies for treating MSM.

Regulation of gut bacteria in silkworm (Bombyx mori) after exposure to endogenous cadmium-polluted mulberry leaves

Soil cadmium (Cd) pollution presents a severe pollution burden to flora and fauna due to its non-degradability and transferability. The Cd in the soil is stressing the silkworm (Bombyx mori) out through a soil-mulberry-silkworm system. The gut microbiota of B.mori are reported to shape host health. However, earlier research had not reported the effect of endogenous Cd-polluted mulberry leaves on the gut microbiota of B.mori. In the current research, we compared the phyllosphere bacteria of endogenous Cd-polluted mulberry leaves at different concentrations. The investigation of the gut bacteria of B.mori fed with the mulberry leaves was done to evaluate the impact of endogenous Cd- polluted mulberry leaves on the gut bacteria of the silkworm. The results revealed a dramatic change in the gut bacteria of B.mori whereas, the changes in the phyllosphere bacteria of mulberry leaves in response to an increased Cd concentration were insignificant. It also increased the α-diversity and altered the gut bacterial community structure of B. mori. A significant change in the abundance of dominant phyla of gut bacteria of B.mori was recorded. At the genus level, the abundance of Enterococcus, Brachybacterium and Brevibacterium group related to disease resistance, and the abundance of Sphingomonas, Glutamicibacter and Thermus related to metal detoxification was significantly increased after Cd exposure. Meanwhile, there was a significant decrease in the abundance of the pathogenic bacteria Serratia and Enterobacter. The results demonstrated that endogenous Cd-polluted mulberry leaves caused perturbations in the gut bacterial composition of B.mori, which may driven by Cd content rather than phyllosphere bacteria. A significant variation in the specific bacterial community indicated the adaptation of B. mori gut for its role in heavy metal detoxification and immune function regulation. The results of this study help to understand the bacterial community associated with endogenous Cd-polluted resistance in the gut of B.mori, which proves to be a novel addition in describing its response in activating the detoxification mechanism and promoting its growth and development. This research work will help to explore the other mechanisms and microbiota associated with the adaptations to mitigate the Cd pollution problems.

Conserved FimK Truncation Coincides with Increased Expression of Type 3 Fimbriae and Cultured Bladder Epithelial Cell Association in Klebsiella quasipneumoniae

Klebsiella spp. commonly cause both uncomplicated urinary tract infection (UTI) and recurrent UTI (rUTI). Klebsiella quasipneumoniae, a relatively newly defined species of Klebsiella, has been shown to be metabolically distinct from Klebsiella pneumoniae, but its type 1 and type 3 fimbriae have not been studied. K. pneumoniae uses both type 1 and type 3 fimbriae to attach to host epithelial cells. The type 1 fimbrial operon is well conserved between Escherichia coli and K. pneumoniae apart from fimK, which is unique to Klebsiella spp. FimK contains an N-terminal DNA binding domain and a C-terminal phosphodiesterase (PDE) domain that has been hypothesized to cross-regulate type 3 fimbriae expression via modulation of cellular levels of cyclic di-GMP. Here, we find that a conserved premature stop codon in K. quasipneumoniae fimK results in truncation of the C-terminal PDE domain and that K quasipneumoniae strain KqPF9 cultured bladder epithelial cell association and invasion are dependent on type 3 but not type 1 fimbriae. Further, we show that basal expression of both type 1 and type 3 fimbrial operons as well as cultured bladder epithelial cell association is elevated in KqPF9 relative to uropathogenic K. pneumoniae TOP52. Finally, we show that complementation of KqPF9ΔfimK with the TOP52 fimK allele reduced type 3 fimbrial expression and cultured bladder epithelial cell attachment. Taken together these data suggest that the C-terminal PDE of FimK can modulate type 3 fimbrial expression in K. pneumoniae and its absence in K. quasipneumoniae may lead to a loss of type 3 fimbrial cross-regulation. IMPORTANCE K. quasipneumoniae is often indicated as the cause of opportunistic infections, including urinary tract infection, which affects >50% of women worldwide. However, the virulence factors of K. quasipneumoniae remain uninvestigated. Prior to this work, K. quasipneumoniae and K. pneumoniae had only been distinguished phenotypically by metabolic differences. This work contributes to the understanding of K. quasipneumoniae by evaluating the contribution of type 1 and type 3 fimbriae, which are critical colonization factors encoded by all Klebsiella spp., to K. quasipneumoniae bladder epithelial cell attachment in vitro. We observe clear differences in bladder epithelial cell attachment and regulation of type 3 fimbriae between uropathogenic K. pneumoniae and K. quasipneumoniae that coincide with a structural difference in the fimbrial regulatory gene fimK.

Contemporary Management of Urinary Tract Infections in Children

Purpose of Review

Urinary tract infection (UTI) in children is a major source of office visits and healthcare expenditure. Research into the diagnosis, treatment, and prophylaxis of UTI has evolved over the past 10 years. The development of new imaging techniques and UTI screening tools has improved our diagnostic accuracy tremendously. Identifying who to treat is imperative as the increase in multi-drug-resistant organisms has emphasized the need for antibiotic stewardship. This review covers the contemporary management of children with UTI and the data-driven paradigm shifts that have been implemented into clinical practice.

Recent Findings

With recent data illustrating the self-limiting nature and low prevalence of clinically significant vesicoureteral reflux (VUR), investigational imaging in children has become increasingly less frequent. Contrast-enhanced voiding urosonogram (CEVUS) has emerged as a useful diagnostic tool, as it can provide accurate detection of VUR without the need of radiation. The urinary and intestinal microbiomes are being investigated as potential therapeutic drug targets, as children with recurrent UTIs have significant alterations in bacterial proliferation. Use of adjunctive corticosteroids in children with pyelonephritis may decrease the risk of renal scarring and progressive renal insufficiency. The development of a vaccine against an antigen present on Escherichia coli may change the way we treat children with recurrent UTIs.

Summary

The American Academy of Pediatrics defines a UTI as the presence of at least 50,000 CFU/mL of a single uropathogen obtained by bladder catheterization with a dipstick urinalysis positive for leukocyte esterase (LE) or WBC present on urine microscopy. UTIs are more common in females, with uncircumcised males having the highest risk in the first year of life. E. coli is the most frequently cultured organism in UTI diagnoses and multi-drug-resistant strains are becoming more common. Diagnosis should be confirmed with an uncontaminated urine specimen, obtained from mid-stream collection, bladder catheterization, or suprapubic aspiration. Patients meeting criteria for imaging should undergo a renal and bladder ultrasound, with further investigational imaging based on results of ultrasound or clinical history. Continuous antibiotic prophylaxis is controversial; however, evidence shows patients with high-grade VUR and bladder and bowel dysfunction retain the most benefit. Open surgical repair of reflux is the gold standard for patients who fail medical management with endoscopic approaches available for select populations.

Urinary Tract Infections: 2021 Update

Catheter-associated urinary tract infection (CAUTI) remains one of the most prevalent, but preventable, health care-associated infections and predominantly occurs in patients with indwelling urinary catheters. Duration of urinary catheterization is the most important modifiable risk factor for development of CAUTI. Alternatives to indwelling catheters should be considered in appropriate patients. If indwelling catheterization is necessary, proper aseptic practices for catheter insertion and maintenance and use of a closed catheter collection system are essential for preventing CAUTI. The use of intervention bundles and collaboratives helps in the effective implementation of CAUTI prevention measures.

Enterobacter aerogenes ZDY01 inhibits choline-induced atherosclerosis through CDCA-FXR-FGF15 axis

Atherosclerosis is the leading cause of cardiovascular diseases worldwide. Trimethylamine N-oxide (TMAO), a metabolite of intestinal flora from dietary quaternary amines, has been shown to be closely related to the development of atherosclerosis. Previous studies have shown that Enterobacter aerogenes ZDY01 significantly reduces the serum levels of TMAO and cecal trimethylamine (TMA) in Balb/c mice; however, its role in the inhibition of choline-induced atherosclerosis in ApoE^-/- mice remains unclear. Here, we demonstrated that E. aerogenes ZDY01 inhibited choline-induced atherosclerosis in ApoE^-/- mice fed with 1.3% choline by reducing cecal TMA and modulating CDCA-FXR/FGF15 axis. We observed that E. aerogenes ZDY01 decreased the cecal TMA and serum TMAO levels by utilizing cecal TMA as a nutrient, not by changing the expression of hepatic FMO3 and the composition of gut microbiota. Furthermore, E. aerogenes ZDY01 enhanced the expression of bile acid transporters and reduced the cecal CDCA levels, thereby attenuating the FXR/FGF15 pathway, upregulating the expression of Cyp7a1, promoting reverse cholesterol transport. Taken together, E. aerogenes ZDY01 attenuated choline-induced atherosclerosis in ApoE^-/- mice by decreasing cecal TMA and promoting reverse cholesterol transport, implying that E. aerogenes ZDY01 treatment might have therapeutic potential in atherosclerosis.

Prioritization of potential drug targets and antigenic vaccine candidates against Klebsiella aerogenes using the computational subtractive proteome-driven approach

Klebsiella aerogenes is a multidrug-resistant Gram-negative bacterium that causes nosocomial infections. The organism showed resistance to most of the conventional antibiotics available. Because of the high resistance of the species, the treatment of K. aerogenes is difficult. These species are resistant to third-generation cephalosporins due to the production of chromosomal beta-lactams with cephalosporin activity. The lack of better treatment and the development of therapeutic resistance in hospitals hinders better/new broad-spectrum-based treatment against this pathogen. This study identifies potential drug targets/vaccine candidates through a computational subtractive proteome-driven approach. This method is used to predict proteins that are not homologous to humans and human symbiotic intestinal flora. The resultant proteome of K. aerogenes was further searched for proteins, which are essential, virulent, and determinants of antibiotic/drug resistance. Subsequently, their druggability properties were also studied. The data set was reduced based on its presence in the pathogen-specific metabolic pathways. The subtractive proteome analysis predicted 13 proteins as potential drug targets for K. aerogenes. Furthermore, these target proteins were annotated based on their spectrum of activity, cellular localization, and antigenicity properties, which ensured that they are potent candidates for broad-spectrum antibiotic and vaccine design. The results open up new opportunities for designing and manufacturing powerful antigenic vaccines against K. aerogenes and the detection and release of new and active drugs against K. aerogenes without altering the gut microbiome.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42485-021-00068-9.

Epidemiologic profile of nosocomial infections among paediatric patients in a referral hospital in Hamadan, west of Iran

Healthcare-associated infections (HC-AI) are major health problem with high financial impact. HC-AIs are one of the main causes of morbidity and mortality in paediatric hospitals. This study was performed to determine the epidemiology of HC-AIs in children admitted to medical wards of Besat Hospital in Hamadan, west of Iran. Data on cases of HC-AIs in paediatrics were collected from March 2017 to February 2018 in Besat Hospital. The medical records of eligible cases were extracted from Iranian Nosocomial Infections Surveillance Software. During the study period, a total of 355 HC-AIs in children were detected, 213 (60%) in boys and 214 (60.3%) in the 0-4-year age group. Of these, bloodstream infection was the most frequent infection in both age groups (37.38% in 0-4 years and 34.75% in 5-14 years). Escherichia coli was the common detected microorganism in girls (25.84% in those aged 0-4 years and 24.53% in 5-14 years), whereas Staphylococcus was more prevalent in boys (33.6% in those aged 0-4 years and 29.55% in 5-14 years). HC-AIs were more prevalent in burn, haematology and intensive care unit wards. In Besat Hospital, bloodstream infection and urinary tract infection were the most frequent infections among paediatric patients, and E. coli and Staphylococcus were the commonest detected microorganism in girls and boys respectively. Preventive activities should be targeted to reduce the rate of HC-AIs in wards associated with more contamination.

Establishment of a Molecular Serotyping Scheme and a Multiplexed Luminex-Based Array for Enterobacter aerogenes

Serotyping based on surface polysaccharide antigens is important for the clinical detection and epidemiological surveillance of pathogens. Polysaccharide gene clusters (PSgcs) are typically responsible for the diversity of bacterial surface polysaccharides. Through whole-genome sequencing and analysis, eight putative PSgc types were identified in 23 Enterobacter aerogenes strains from several geographic areas, allowing us to present the first molecular serotyping system for E. aerogenes. A conventional antigenic scheme was also established and correlated well with the molecular serotyping system that was based on PSgc genetic variation, indicating that PSgc-based molecular typing and immunological serology provide equally valid results. Further, a multiplex Luminex-based array was developed, and a double-blind test was conducted with 97 clinical specimens from Shanghai, China, to validate our array. The results of these analyses indicated that strains containing PSgc4 and PSgc7 comprised the predominant groups. We then examined 86 publicly available E. aerogenes strain genomes and identified an additional seven novel PSgc types, with PSgc10 being the most abundant type. In total, our study identified 15 PSgc types in E. aerogenes, providing the basis for a molecular serotyping scheme. From these results, differing epidemic patterns were identified between strains that were predominant in different regions. Our study highlights the feasibility and reliability of a serotyping system based on PSgc diversity, and for the first time, presents a molecular serotyping system, as well as an antigenic scheme for E. aerogenes, providing the basis for molecular diagnostics and epidemiological surveillance of this important emerging pathogen.

Development of a panel of recombinase polymerase amplification assays for detection of common bacterial urinary tract infection pathogens

AIMS

To develop and evaluate the performance of a panel of isothermal real-time recombinase polymerase amplification (RPA) assays for detection of common bacterial urinary tract infection (UTI) pathogens.

METHODS AND RESULTS

The panel included RPAs for Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterococcus faecalis. All five RPAs required reaction times of under 12 min to reach their lower limit of detection of 100 genomes per reaction or less, and did not cross-react with high concentrations of nontarget bacterial genomic DNA. In a 50-sample retrospective clinical study, the five-RPA assay panel was found to have a specificity of 100% (95% CI, 78-100%) and a sensitivity of 89% (95% CI, 75-96%) for UTI detection.

CONCLUSIONS

The analytical and clinical validity of RPA for the rapid and sensitive detection of common UTI pathogens was established.

SIGNIFICANCE AND IMPACT OF THE STUDY

Rapid identification of the causative pathogens of UTIs can be valuable in preventing serious complications by helping avoid the empirical treatment necessitated by traditional urine culture's 48-72-h turnaround time. The routine and widespread use of RPA to supplement or replace culture-based methods could profoundly impact UTI management and the emergence of multidrug-resistant pathogens.

Evaluation of multifarious plant growth promoting traits, antagonistic potential and phylogenetic affiliation of rhizobacteria associated with commercial tea plants grown in Darjeeling, India

Plant growth promoting rhizobacteria (PGPR) are studied in different agricultural crops but the interaction of PGPR of tea crop is not yet studied well. In the present study, the indigenous tea rhizobacteria were isolated from seven tea estates of Darjeeling located in West Bengal, India. A total of 150 rhizobacterial isolates were screened for antagonistic activity against six different fungal pathogens i.e. Nigrospora sphaerica (KJ767520), Pestalotiopsis theae (ITCC 6599), Curvularia eragostidis (ITCC 6429), Glomerella cingulata (MTCC 2033), Rhizoctonia Solani (MTCC 4633) and Fusarium oxysporum (MTCC 284), out of which 48 isolates were antagonist to at least one fungal pathogen used. These 48 isolates exhibited multifarious antifungal properties like the production of siderophore, chitinase, protease and cellulase and also plant growth promoting (PGP) traits like IAA production, phosphate solubilization, ammonia and ACC deaminase production. Amplified ribosomal DNA restriction analysis (ARDRA) and BOX-PCR analysis based genotyping clustered the isolates into different groups. Finally, four isolates were selected for plant growth promotion study in two tea commercial cultivars TV-1 and Teenali-17 in nursery conditions. The plant growth promotion study showed that the inoculation of consortia of these four PGPR isolates significantly increased the growth of tea plant in nursery conditions. Thus this study underlines the commercial potential of these selected PGPR isolates for sustainable tea cultivation.

The Effects of Bundles on Catheter-Associated Urinary Tract Infections in the Pediatric Intensive Care Unit

BACKGROUND

There are few studies in the literature from developing countries regarding the rates of catheter-associated urinary tract infection (CAUTI), which is frequently encountered in pediatric intensive care units (PICUs).

AIM

The aim of this study is to evaluate the 2-year rates of CAUTI in a PICU where a CAUTI Prevention Bundle was implemented.

DESIGN

This was an interventional prospective study.

METHODS

The study was conducted with 390 patients in the PICU of Istanbul Faculty of Medicine, Turkey, from July 2013 to July 2015. The patients were selected based on the diagnostic criteria of the Centers for Disease Control and Prevention.

RESULTS

Urinary colonization occurred in 8 (2.2%) patients in the prebundle group and 3 (0.8%) patients in the postbundle group, and contamination occurred in 10 (2.8%) patients in the prebundle group and 6 (1.5%) patients in the postbundle group. The CAUTI incidence and rates were 5.8% and 6.1 per 1000 urinary catheter days and 1.5% and 1.8 per 1000 urinary catheter days prebundle and postbundle, respectively. There was a statistically significant difference between the prebundle and postbundle CAUTI rates.

CONCLUSION

Our findings support that clinical nurse specialists in developing countries should consider the use of CAUTI bundles to prevent CAUTIs.

Epidemiologic and microbiologic evaluation of nosocomial infections associated with Candida spp in children: A multicenter study from Istanbul, Turkey

BACKGROUND

The purpose of this study was to establish species distribution of Candida isolates from pediatric patients in Istanbul, Turkey, and to determine risk factors associated with nosocomial Candida infections.

METHODS

This study was conducted between June 2013 and June 2014 by participation of 7 medical centers in Istanbul. Candida spp strains isolated from the clinical specimens of pediatric patients were included. Clinical features were recorded on a standardized data collection sheet.

RESULTS

A total of 134 systemic Candida infections were identified in 134 patients. The patients were admitted in pediatric and neonatal intensive care units (41.8% and 9.7%, respectively) and in pediatric wards (48.5%). Candida albicans was the most prevalent species (47%), followed by Candida parapsilosis (13.4%), Candida tropicalis (8.2%), Candida glabrata (4.5%), Candida lusitaniae (3.7%), Candida kefyr (2.2%), Candida guilliermondii (1.5%), Candida dubliniensis (0.7%), and Candida krusei (0.7%). Types of Candida infections were candidemia (50.7%), urinary tract infection (33.6%), surgical site infection (4.5%), central nervous system infection (3.7%), catheter infection (3.7%), and intra-abdominal infection (3.7%). In multivariate analysis, younger age (1-24 months) and detection of non-albicans Candida spp was found to be risk factors associated with candidemia (P = 0.040; odds ratio [OR], 4.1; 95% confidence interval [CI], 1.06-15.86; and P = 0.02; OR, 2.4; 95% CI, 1.10-5.53, respectively).

CONCLUSIONS

This study provides an update for the epidemiology of nosocomial Candida infections in Istanbul, which is important for the management of patients and implementation of appropriate infection control measures.

Comparison of Febrile Infants With Enterococcal and Gram-negative Urinary Tract Infections

BACKGROUND

Few data exist on the presentations and clinical courses of infants with enterococcal urinary tract infections (UTI). The objective of this study was to compare the clinical presentation, sensitivity of urinalysis (UA) and Gram's stain, radiological abnormalities and adverse events of febrile infants with enterococcal UTIs to those with Gram-negative UTIs.

METHODS

Retrospective study of febrile (≥38.0°C) infants 29-60 days of age with UTIs at 20 emergency departments. UTI was defined as growth of (1) ≥50,000 colony forming units (CFUs)/mL of a single pathogen; or (2) either 10,000 to <50,000 CFUs/mL or 10,000-100,000 CFUs/mL (depending on laboratory reporting) with a positive UA or Gram's stain.

RESULTS

Thirty-seven (2.0%) of 1870 infants with febrile UTIs had enterococcal UTIs. On bivariable analysis, infants with enterococcal UTIs more frequently had histories of prematurity, previous hospitalizations, histories of genitourinary abnormalities, previous UTIs and ill-appearance in the emergency department compared with infants with Gram-negative UTIs (all P <0.05). On multivariable analysis, ≥ grade 3 vesicoureteral reflux (adjusted odds ratio 3.2, 95% confidence interval: 1.4, 7.6) and hydronephrosis (adjusted odds ratio 3.3, 95% confidence interval: 1.4, 7.9) were associated with enterococcal UTIs. Both groups had similar low risks of adverse events or severe clinical courses. The urine white blood cell count alone or in combination with leukocyte esterase was more sensitive for Gram-negative than enterococcal UTIs (range 80.4%-93.9% vs. 50.0%-75.9%).

CONCLUSIONS

Febrile infants with enterococcal UTIs had a low likelihood of adverse events or severe clinical course, similar to those with Gram-negative UTIs. Infants with enterococcal UTIs frequently had underlying hydronephrosis and/or vesicoureteral reflux. The preliminary diagnosis of enterococcal UTIs may be inaccurate if based on UA.

The Impact of Catheter-Associated Urinary Tract Infection (CA-UTI) in Critically Ill Children in the Pediatric Intensive Care Unit

Objective Catheter-associated urinary tract infections (CA-UTIs) comprise a significant proportion of hospital-acquired infections. However, the impact of CA-UTIs on important outcome measures, such as length of stay (LOS) and hospital charges, has not been examined in the pediatric intensive care unit (PICU) setting. Design Single-center, retrospective, case-matched, cohort study and financial analysis. Setting PICU in a tertiary-care children's medical center. Patients A total of 41 critically ill children with CA-UTIs and 73 critically ill children without CA-UTI, matched for age, gender, severity of illness, and primary admission diagnosis. Interventions None. Measurements and Main Results We compared the length of hospital stay (LOS in PICU and in hospital), mortality, and hospital costs in critically ill children with CA-UTIs and their matched controls. Critically ill children experiencing CA-UTI had significantly longer PICU LOS, hospital LOS, duration of mechanical ventilation, and mortality compared with matched controls without CA-UTI. The longer LOS resulted in higher PICU and hospital charges in this group. Conclusion Critically ill children with CA-UTI experience worse outcomes in the PICU compared with those without CA-UTI. Further studies on the impact of CA-UTI in the PICU are warranted.

Enterobacter aerogenes and Enterobacter cloacae; versatile bacterial pathogens confronting antibiotic treatment

Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membrane permeability ensuring the bacterial protection and the expression of detoxifying enzymes involved in antibiotic degradation/inactivation. In addition, these bacterial species are able to acquire numerous genetic mobile elements that strongly contribute to antibiotic resistance. Moreover, this particular fitness help them to colonize several environments and hosts and rapidly and efficiently adapt their metabolism and physiology to external conditions and environmental stresses. Enterobacter is a versatile bacterium able to promptly respond to the antibiotic treatment in the colonized patient. The balance of the prevalence, E. aerogenes versus E. cloacae, in the reported hospital infections during the last period, questions about the horizontal transmission of mobile elements containing antibiotic resistance genes, e.g., the efficacy of the exchange of resistance genes Klebsiella pneumoniae to Enterobacter sp. It is also important to mention the possible role of antibiotic use in the treatment of bacterial infectious diseases in this E. aerogenes/E. cloacae evolution.

Risk Factors for Catheter Associated Urinary Tract Infections in a Pediatric Institution

PURPOSE

Catheter associated urinary tract infections are an essential measure for health care quality improvement that affects reimbursement through hospital acquired condition reduction programs in adult patients. With the mounting importance of preventing such infections we evaluated risk factors for acquiring catheter associated urinary tract infections in pediatric patients.

MATERIALS AND METHODS

All catheter associated urinary tract infections were identified at 1 pediatric institution from September 2010 to August 2014 from a prospective database maintained by the infection control office. To identify risk factors patients with a catheter associated urinary tract infection were individually matched to control patients with a urinary catheter but without infection by age, gender, date and the hospital location of the infection in 1:2 fashion.

RESULTS

A total of 50 patients with catheter associated urinary tract infection were identified and matched to 100 control patients. Compared to controls the patients with infection were more likely to have a catheter in place for longer (2.9 days, OR 1.08, 95% CI 1.01, 1.15, p = 0.02). They were also more likely to be on contact precautions (OR 4.00, 95% CI 1.73, 9.26, p = 0.001), and have concurrent infections (OR 3.04, 95% CI 1.39, 6.28, p = 0.005) and a history of catheterization (OR 3.24, 95% CI 1.55, 6.77, p = 0.002). Using a conditional multivariate regression model the 3 most predictive variables were duration of catheter drainage, contact isolation status and history of catheterization.

CONCLUSIONS

Longer duration of urinary catheter drainage, positive contact precautions status and a history of catheterization appear to be associated with a higher risk of catheter associated urinary tract infection in hospitalized pediatric patients. Physicians should attempt to decrease the duration of catheterization, especially in patients who meet these criteria, to minimize the risk of catheter associated urinary tract infection.

Acute Nosocomial Urinary Tract Infection in Children

The spectrum and antimicrobial susceptibilities of pathogens causing acute nosocomial urinary tract infection in hospitalized pediatric patients were revealed to be heterogeneous. Therefore, to avoid the failure of empirical antimicrobial therapy in these patients, underlying disease and previous antimicrobial treatment have to be considered.

Prevalence of Nosocomial Infections in Swiss Children's Hospitals

Objective:

To acquire data on pediatric nosocomial infections (NIs), which are associated with substantial morbidity and mortality and for which data are scarce.

Design:

Prevalence survey and evaluation of a new comorbidity index.

Setting:

Seven Swiss pediatric hospitals.

Patients:

Those hospitalized for at least 24 hours in a medical, surgical, intensive care, or intermediate care ward.

Results:

Thirty-five NIs were observed among 520 patients (6.7%; range per hospital, 1.4% to 11.8%). Bacteremia was most frequent (2.5 per 100 patients), followed by urinary tract infection (1.3 per 100 patients) and surgical-site infection (1.1 per 100 patients; 3.2 per 100 patients undergoing surgery). The median duration until the onset of infection was 19 days. Independent risk factors for NI were age between 1 and 12 months, a comorbidity score of 2 or greater, and a urinary catheter. Among surgical patients, an American Society of Anesthesiologists (ASA) score of 2 or greater was associated with any type of NI (P = .03). Enterobacteriaceae were the most frequent cause of NI, followed by coagulase-negative staphylococci; viruses were rarely the cause.

Conclusions:

This national prevalence survey yielded valuable information about the rate and risk factors of pediatric NI. A new comorbidity score showed promising performance. ASA score may be a predictor of NI. The season in which a prevalence survey is conducted must be considered, as this determines whether seasonal viral infections are observed. Periodic prevalence surveys are a simple and cost-effective method for assessing NI and comparing rates among pediatric hospitals.

Transcriptional activation of the mrkA promoter of the Klebsiella pneumoniae type 3 fimbrial operon by the c-di-GMP-dependent MrkH protein

The Gram-negative bacterial pathogen Klebsiella pneumoniae forms biofilms to facilitate colonization of biotic and abiotic surfaces. The formation of biofilms by K. pneumoniae requires the expression of type 3 fimbriae: elongate proteinaceous filaments extruded by a chaperone-usher system in the bacterial outer membrane. The expression of the mrkABCDF cluster that encodes this fimbrial system is strongly positively regulated by MrkH, a transcriptional activator that responds to the second messenger, c-di-GMP. In this study, we analyzed the mechanism by which the MrkH protein activates transcriptional initiation from the mrkA promoter. A mutational analysis supported by electrophoretic mobility shift assays demonstrated that a 12-bp palindromic sequence (the MrkH box) centered at -78.5 is the binding site of MrkH. Deletion of half a turn, but not a full turn, of DNA located between the MrkH box and the mrkA promoter destroyed the ability of MrkH to activate mrkA transcription. In addition, a 10-bp AT-rich sequence (the UP element) centered at -63.5 contributed significantly to MrkH-dependent mrkA transcription. In vivo analysis of rpoA mutants showed that the R265 and E273 determinants in the C-terminal domain of RNA polymerase α subunit are needed for MrkH-mediated activation of mrkA transcription. Furthermore, results from mutagenesis of the mrkH gene suggest that the N-terminal region of the protein is involved in transcriptional activation. Taken together, our results suggest that MrkH activates mrkA expression by interacting directly with RNA polymerase, to overcome the inefficient transcriptional initiation caused by the presence of defective core promoter elements.

Community-acquired enterococcal urinary tract infections in hospitalized children

The objectives of this study were to characterize community-acquired (CA) enterococcal urinary tract infections (UTIs) in a tertiary pediatric center and to determine risk factors for their occurrence, their association with renal abnormalities, their antibiotic susceptibility profile, and the appropriateness of the empiric antibiotic treatment, in comparison to those of Gram-negative UTIs. In a 5-year prospective clinical and laboratory study, we found that enterococcal UTIs caused 6.2% (22/355) of culture-proven CA UTIs. Compared with Gram-negative UTI, enterococcal UTI was associated with male predominance, higher rates of underlying urinary abnormalities (70 vs. 43.7%; p = 0.03) and inappropriate empiric antibiotic therapy (22 vs. 5.6%; p = 0.02), and mainly vesicoureteral reflux (53% of cases). This study highlights the importance of early detection of CA enterococcal UTIs because of their association with underlying urinary abnormalities and a high rate of inappropriate empiric antibiotic therapy. Renal imaging is recommended for children with enterococcal UTIs; Gram stain is suggested in selected cases to detect Gram-positive cocci for early diagnosis of enterococcal UTIs and initiation of appropriate antibiotics.

Caracterización clínica, microbiológica y de sensibilidad a antimicrobianos en pacientes con infección nosocomial del tracto urinario: cuatro años y medio de vigilancia epidemiológica

Antecedentes: Las infecciones nosocomiales son entidades importantes por su aumento en la morbimortalidad y en los costos de tratamiento. En Medellín, Colombia, la del tracto urinario (ITU)  es  la segunda infección nosocomial  más incidente, 16,3% del total. El objetivo del presente estudio fue realizar  una caracterización de los  aspectos  clínicos  y microbiológicos de los pacientes con infección nosocomial del tracto urinario en una clínica privada de Medellín, Colombia. Métodos: Estudio retrospectivo, longitudinal, descriptivo de las historias clínicas de los pacientes con infección nosocomial del tracto urinario entre enero/2005 y julio/2009. Resultados: Se diagnosticaron 134 casos en 130 pacientes (tasa institucional de 0,27 infecciones por 100 egresos), con alza de 0,21 por cada 100 egresos en 2005 a 0,59 en 2009. La mayoría de los pacientes fueron mujeres (67,7%), con edad promedio de 55 (IQ 27-72) años.  Las comorbilidades más comunes fueron hipertensión arterial  (48,5%)  y enfermedad renal  crónica (16,3%). Los gérmenes más comunes fueron E. coli (54,9%) y K. pneumoniae (12,8%). Hay alta proporción de resistencia a ciprofloxacina,  ampicilina/sulbactam y  trimetoprim/sulfametoxazol.  Conclusión:  La ITU nosocomial  es una entidad relativamente común en la institución estudiada, aunque su tasa es consistentemente inferior a la encontrada en estudios similares. Para el manejo empírico de esta infección parece recomendable iniciar con amikacina o ceftriaxona, utilizando imipenem o meropenem en pacientes sépticos con comorbilidad seria o con alto riesgo de gérmenes multirresistentes. Para el tratamiento de ITU nosocomial por E. coli, la amikacina y la gentamicina parecen buenas  opciones,  al  igual  que la ceftriaxona.

Study of nosocomial urinary tract infections in a pediatric intensive care unit

Nosocomial urinary tract infections (NUTI) are one of the commonest infections in a Pediatric Intensive Care Unit (PICU). This prospective study was conducted in PICU between January and December 2008 to study the incidence, organisms and risk factors for NUTI. A total of 287 consecutive patients with >48 h PICU stay and sterile admission urine culture, were enrolled and monitored for NUTI (defined as per CDC criteria 1988) till discharge or death. Patients with and without NUTI were compared with respect to demographics, PRISM scores, primary diagnosis, nutritional status and device utilization to identify risk factors. Outcome was defined as length of PICU stay and survival or death. There were 69 episodes of UTI in 60 (20.9%) patients; incidence being 18 episodes/1000 patient days. Candida (52.1%) and Enterococcus (13%) were commonest followed by Escherichia coli (11.6%) and Klebsiella pneumoniae (10.1%). Catheterization and duration of catheterization were the risk factors for NUTI (p < 0.001). The median length of PICU stay was significantly longer in NUTI group compared to non-NUTI group (19 vs. 8 days, p = 0.001). Mortality rates in both the groups were similar.

MrkH, a novel c-di-GMP-dependent transcriptional activator, controls Klebsiella pneumoniae biofilm formation by regulating type 3 fimbriae expression

Klebsiella pneumoniae causes significant morbidity and mortality worldwide, particularly amongst hospitalized individuals. The principle mechanism for pathogenesis in hospital environments involves the formation of biofilms, primarily on implanted medical devices. In this study, we constructed a transposon mutant library in a clinical isolate, K. pneumoniae AJ218, to identify the genes and pathways implicated in biofilm formation. Three mutants severely defective in biofilm formation contained insertions within the mrkABCDF genes encoding the main structural subunit and assembly machinery for type 3 fimbriae. Two other mutants carried insertions within the yfiN and mrkJ genes, which encode GGDEF domain- and EAL domain-containing c-di-GMP turnover enzymes, respectively. The remaining two isolates contained insertions that inactivated the mrkH and mrkI genes, which encode for novel proteins with a c-di-GMP-binding PilZ domain and a LuxR-type transcriptional regulator, respectively. Biochemical and functional assays indicated that the effects of these factors on biofilm formation accompany concomitant changes in type 3 fimbriae expression. We mapped the transcriptional start site of mrkA, demonstrated that MrkH directly activates transcription of the mrkA promoter and showed that MrkH binds strongly to the mrkA regulatory region only in the presence of c-di-GMP. Furthermore, a point mutation in the putative c-di-GMP-binding domain of MrkH completely abolished its function as a transcriptional activator. In vivo analysis of the yfiN and mrkJ genes strongly indicated their c-di-GMP-specific function as diguanylate cyclase and phosphodiesterase, respectively. In addition, in vitro assays showed that purified MrkJ protein has strong c-di-GMP phosphodiesterase activity. These results demonstrate for the first time that c-di-GMP can function as an effector to stimulate the activity of a transcriptional activator, and explain how type 3 fimbriae expression is coordinated with other gene expression programs in K. pneumoniae to promote biofilm formation to implanted medical devices.

Biofilms are surface-associated communities of microorganisms. Biofilm-associated bacteria are protected from host defenses and antibiotics and are the cause of many infections. Klebsiella pneumoniae is primarily a hospital-acquired bacterial pathogen that causes pneumonia, urinary tract infections and septicemia. Its success is related to its ability to form biofilms on medical devices, such as catheters. In K. pneumoniae, biofilm formation is mediated by type 3 fimbriae – hair-like, protein appendages extending out from the cell surface that adhere to surfaces. This study investigated how K. pneumoniae regulates the expression of these fimbriae. We identified a protein, MrkH, which behaves as a “biofilm switch” that turns on the expression of genes responsible for producing type 3 fimbriae. MrkH works by binding to regulatory regions of DNA nearby to these genes and initiates their expression. Importantly, MrkH binds to DNA strongly only when the protein is stimulated by a small molecule, c-di-GMP. Furthermore, we identified bacterial enzymes that either produce or break down c-di-GMP to control its concentration within the cell, and thus modulate MrkH activity. Understanding the molecular basis for these processes may lead to the development of therapeutic compounds, possibly for incorporation into medical device materials to inhibit biofilm formation and pathogenesis.

Urinary tract infections

Catheter-associated urinary tract infections (CAUTIs) account for approximately 40% of all health care-associated infections. Despite studies showing benefit of interventions for prevention of CAUTI, adoption of these practices has not occurred in many healthcare facilities in the United States. As urinary catheters account for the majority of healthcare-associated UTIs, the most important interventions are directed at avoiding placement of urinary catheters and promoting early removal when appropriate. Alternatives to indwelling catheters such as intermittent catheterization and condom catheters should be considered. If indwelling catheterization is appropriate, proper aseptic practices for catheter insertion and maintenance and use of a closed catheter collection system are essential for preventing CAUTI. The use of antimicrobial catheters also may be considered when the rates of CAUTI remain persistently high despite adherence to other evidence-based practices, or in patients deemed to be at high risk for CAUTI or its complications. Attention toward prevention of CAUTI will likely increase as Center for Medicare and Medicaid Services and other third-party payers no longer reimburse for hospital-acquired UTI.

Genetic analysis of faropenem-resistant Enterococcus faecalis in urinary isolates

We isolated faropenem-resistant Enterococcus faecalis in urine specimens and studied the mechanisms of resistance to faropenem in these isolates. Three mechanisms of penicillin resistance have been reported in E. faecalis; (1) beta-lactamase production, (2) overproduction of penicillin-binding protein (PBP) 4 or PBP5, and (3) decreasing affinities of penicillins for PBP4 by the occurrence of point mutations of the penicillin-binding domain. None of the E. faecalis isolates examined produced beta-lactamase or overproduced any PBPs, but the affinities of faropenem for PBP4 were decreased in faropenem-insensitive and -resistant strains. We found single amino acid substitutions at positions 475, 520 or 605 in PBP4 in the insensitive strains and two amino acid substitutions at positions 520 and 605 in PBP4 in the resistant strains by sequencing the entire pbp4 gene from each isolate. We conclude that development of resistance to faropenem in E. faecalis is due to decreasing affinities for PBP4 that are the result of the occurrence of one or two point mutations.

Infectious disease hospitalizations among infants in the United States

OBJECTIVE

This study describes the burden and epidemiologic features of infectious disease hospitalizations among infants in the United States.

METHODS

Hospitalizations with an infectious disease listed as a primary diagnosis for infants (<1 year of age) in the United States during 2003 were examined by using the Kids' Inpatient Database. National estimates of infectious disease hospitalizations, hospitalization rates, and various hospital parameters were examined.

RESULTS

During 2003, an estimated 286,739 infectious disease hospitalizations occurred among infants in the United States and accounted for 42.8% of all infant hospitalizations. The national infectious disease hospitalization rate was 7010.8 hospitalizations per 100,000 live births, or approximately 1 infectious disease hospitalization for every 14 infants. The median length of stay was 3 days, and stays totaled >1 million hospital days for infants. Infectious disease hospitalization rates were highest among boys and nonwhite infants. The most commonly listed diagnoses among the infant infectious disease hospitalizations included lower respiratory tract infections (59.0%), kidney, urinary tract, and bladder infections (7.6%), upper respiratory tract infections (6.5%), and septicemia (6.5%). The median cost of an infectious disease hospitalization was $2235, with total annual hospital costs of approximately $690 million, among infants in the United States.

CONCLUSIONS

Infectious disease hospitalizations among infants account for substantial health care expenditures and hospital time in the United States, with respiratory disease hospitalizations constituting more than one half of all hospitalizations. Younger infants, boys, and nonwhite infants were at increased risk for infectious disease hospitalization. Measures to reduce racial disparities and the occurrence of respiratory tract infections should substantially decrease the infectious disease burden among infants.

Nosocomial Gram-positive bacterial infections in children: results of a 7 year study

BACKGROUND

The aim of the present paper was to determine the rate of culture-proven nosocomial infections and evaluate the episodes of nosocomial Gram-positive (GP) bacterial infections in pediatric patients.

METHODS

The data of children with positive culture, who were diagnosed as having nosocomial infection on the Centers for Disease Control and Prevention criteria, were examined and only the patients with nosocomial GP bacterial infections were included in the study.

RESULTS

Between January 1997 and January 2004 a total of 836 episodes of nosocomial GP bacterial infections were observed. The most frequently seen nosocomial GP bacterial infections were primary bloodstream infections (BSI; 43%), ventriculoperitoneal shunt infections (18%), and nosocomial pneumonias (11%). Coagulase-negative staphylococci (CONS; 46%) were the most common nosocomial GP bacteria isolated, followed by Staphylococcus aureus (33%). Methicillin resistance rates for CONS and S. aureus were 85% and 25.2%; respectively. The mortality rate was 4% of all children with nosocomial GP bacterial infections in the present study.

CONCLUSION

In the present patients primary BSI were the most common nosocomial GP bacterial infections and CONS were the most frequent GP pathogen isolated. Antimicrobial resistance in GP isolates is an increasing problem.

Can we apply the European surveillance program of nosocomial infections (HELICS) to pediatric intensive care units?

OBJECTIVE

To evaluate the applicability of the HELICS program [part of the "Improving Patient Safety in Europe" program aiming at controlling nosocomial infections (NI) through surveillance] in European pediatric ICUs.

DESIGN AND SETTING

A comparison of HELICS and pediatric definitions of the main NI was performed. The adaptability of the HELICS questionnaire for pediatric patients was examined. Then a European survey was carried out by e-mail questionnaire to analyze NI surveillance programs.

PARTICIPANTS

Units affiliated with the European Society of Paediatric and Neonatal Intensive Care or the French Groupe Francophone de Réanimation et Urgences Pédiatriques.

MEASUREMENTS AND RESULTS

The main differences between adult and pediatric ICUs were the definition of ICU-acquired pneumonia, severity scores at admission, and scores of risk for NI. A total of 65 answers from 23 countries were collected. Among them 56 had a NI surveillance program that was of local origin for 64%. The most frequently collected NI were blood stream infections (91% of the units), catheter-related infections (88%), acquired pneumonia (86%), and urinary tract infections (77%). Definitions of NI had a local-based origin in 18% of cases, a regional-based or nation-wide origin in 21%, came from the Centers for Disease Control and Prevention in 38% and had multiple origins in 20%. Seventy-five percent of the units declared an interest in joining a European pediatric working group on NI within the European Society of Paediatric and Neonatal Intensive Care.

CONCLUSIONS

The adaptation of the HELICS protocol for pediatric ICUs is necessary. Its application is largely wished and may be easily performed.

Clinical significance of bacteriuria with low colony counts of Enterococcus species

The clinical significance of low counts of enterococci in urine cultures remains unclear. The goal of this study was to investigate the clinical significance of enterococci growing in numbers lower than 100,000 colony-forming units per milliliter (cfu/ml) in urine samples. Clinical parameters were collected from patients whose midstream clean-catch urine samples grew Enterococcus spp. in amounts between >or=10,000 and 100,000 cfu/ml and who were not previously treated with antibiotics. Only those patients who had leukocyturia in addition to positive culture were considered to have true urinary tract infection (UTI). Of the 208 patients included in the study, 54% were diagnosed with true UTI. Patients with true UTI were older by 6 years (p=0.03), were more likely to be hospitalized (p=0.016), had higher rates of dysuria (p=0.0001), urgency (p=0.0001), and frequency (p=0.0001), and had more solid tumors (p=0.03). By multivariate analysis, urgency (OR=7.1) and hospitalization (OR=4.4) were identified as independent risk factors for true UTI with enterococci in low counts. Enterococcal counts in patients with true UTI were randomly distributed all along the scale between 10,000 and 100,000 cfu/ml, and no differential cutoff could be determined. In conclusion, more than half of the patients whose urine cultures grow Enterococcus spp. in counts lower than 100,000 cfu/ml may have true UTI, especially if they are hospitalized and have symptoms of dysuria, urgency, or frequency. Microbiology laboratories should perform a complete work-up on samples containing low counts of enterococci, and the final interpretation should be done by physicians, using additional clinical information.

Pediatric urinary tract infections

Pediatric urinary tract infections are common. These infections have been recognized as a source of acute morbidity and long-term medical consequences in adulthood. There are various risk factors and clinical presentations in children with urinary tract infections. The main objectives in management include prompt diagnosis, appropriate antimicrobial therapy, identification of anatomic anomalies, and, in select patients, long-term follow-up.

Infection control, hospital epidemiology, and patient safety

Health care-acquired are a major risk for hospitalized children. Similar to adult patients, children are vulnerable to infections related to medical devices. Children also are at significant risk of nosocomial transmission of common pediatric viral illness, such as respiratory syncytial virus and varicella. In addition, pediatric patients have unique or incompletely developed immune system.

Epidemiologische Grundlagen

Eine Vielzahl an Faktoren tragen zu erhöhten nosokomialen Infektionsraten bei. Die Lebenserwartung und damit der Anteil alter Patienten mit z. T. chronischen Krankheiten steigen stetig an. Medizinische Fortschritte in Diagnostik und Therapie führen zu einer höheren Anzahl der dafür erforderlichen Eingriffe. Es werden immer häufiger immunsupprimierte Patienten (Infektiologie, Rheumatologie, Hämatologie/Onkologie, Transplantation von Organen usw.) behandelt. Das zunehmende Problem der Antibiotikaresistenz von Erregern und die Konsequenzen nosokomialer Infektionen erfordern eine verlässliche Epidemiologie auf diesem Gebiet. Konsequenzen betreffen einerseits Patienten, bei denen es zu einer erhöhten Morbidität und Letalität durch nosokomiale Infektionen kommt, aber andererseits auch das Gesundheitswesen, dem zusätzliche — vermeidbare? — finanzielle Belastungen entstehen.

Evidenzbasierte Empfehlungen, bei denen der jeweilige Einzelfall und die örtlichen Besonderheiten ebenfalls Berücksichtigung finden, sind Voraussetzung für eine sinnvolle und kosteneffektive Vorgehensweise zur Senkung der nosokomialen Infektionsrate. In vielen Studien sind Häufigkeiten und Folgen verschiedener nosokomialer Infektionsarten sowie Maßnahmen zu ihrer Prävention untersucht worden. Um die Qualität solcher Studien und die darauf basierenden Empfehlungen von Experten, die ja oftmals ebenfalls mit Kosten verbunden sind, kritisch beurteilen zu können, ist epidemiologisches Wissen unverzichtbar. Dies beinhaltet selbstverständlich auch die Kenntnis der jeweiligen Erreger solcher Infektionen sowie das Wissen um erregerspezifische Übertragungswege. Die Epidemiologie nosokomialer Infektionen ist daher die Grundlage ihrer eigenen Verbesserung.

»Es gibt nicht Kranke und Gesunde, sondern es gibt nur Untersuchte und nicht Untersuchte« (Johannes Rau, ehemaliger Bundespräsident).

Community-acquired enterococcal urinary tract infections

Enterococcal urinary tract infection (UTI) is usually hospital-acquired and affects individuals with predisposing conditions. The aim of this study was to evaluate the community-acquired enterococcal UTIs in otherwise well children. We reviewed all the 257 first UTI episodes in children hospitalized in a General Hospital during a 5-year period. Enterococcus faecalis was isolated in 13 episodes, accounting for 5.1% of the total UTIs. All strains were susceptible to ampicillin, vancomycin and nitrofurantoin. Imaging studies revealed major urinary tract abnormalities in 9 and parenchymal defects in 8 children. During a follow-up period from 2 to 6 years, 4 children suffered break-through infections despite antibiotic prophylaxis, 3 developed renal scarring and 4 underwent corrective surgical procedures. Children with enterococcal UTIs presented with significantly higher rates of anatomical abnormalities and worse prognosis in terms of renal scarring, recurrences and corrective surgery compared with the total cohort of children with Gram-negative UTIs. However children with enterococcal UTIs did not present with a worse prognosis when compared with a group of children with Gram-negative UTIs matched for age and degree of reflux. Enterococcal infection is not an independent risk factor for poor outcome, nevertheless positive urine culture including enterococci is highly indicative for underlying urinary tract abnormalities, recurrences, renal scarring, and need for surgical intervention.

Defining urinary tract infection in the critically ill child

OBJECTIVE

To define urinary tract infections in critically ill children in the intensive care unit setting for the purpose of surveillance of infection, enrollment of children in sepsis trials, and for trials of therapy and prevention.

DESIGN

Summary of the literature with review and consensus by experts in the field.

RESULTS

A variety of definitions, only some of which have been validated for use in children, were identified. The Centers for Disease Control criteria for the definition of nosocomial infection have been used to establish surveillance data for inter-institutional comparison. Validated definitions for the febrile child were identified. Using the known characteristics of symptoms, signs, and laboratory criteria for urinary tract infections, definitions for definite, possible, and probable urinary tract infection were derived.

CONCLUSIONS

Definitions for definite, probable, and possible urinary tract infection were achieved by consensus that can be used for surveillance and enrolment in sepsis trials. Future research should determine the utility of these definitions in the critically ill child and adapt them accordingly.

Urinary tract infection in children: etiology and epidemiology

The urinary tract is a relatively common site of infection in infants and young children. Urinary tract infection (UTI) may result in significant acute morbidity, as well as longterm medical complications. Recent advances elucidating the pathogen-host interaction have broadened the understanding of the pathogenesis and clinical progression of pediatric UTI. This article focuses on the epidemiology and pathogenesis of pediatric UTI, and briefly discusses UTI-related complications.

Prenatal puncture of a unilateral hydronephrosis leading to fetal urinoma and postnatal nephrectomy

Fetal pelvicaliceal dilatation due to ureteropelvic junction obstruction is the most common cause of antenatal hydronephrosis; it rarely leads to a spontaneous rupture resulting in urinoma formation. Antenatal intervention has been recommended only in those cases of large urinomas that seem to interfere with the function of other organ systems (eg, pulmonary hypoplasia secondary to diaphragmatic elevation). We report the case of a fetal intervention (transuterine puncture) in a unilateral massive hydronephrosis leading to a perirenal urinoma and the preterm birth of a female infant. Postnatally, mechanical ventilation and oxygen were required, as was forced percutaneous urinoma drainage. Evaluation revealed a fistula formation between the perirenal space and the kidney's collecting system, possibly due to the fetal intervention. Unfortunately the kidney function was very poor, and surgery to remove the impaired kidney and the urinoma was performed. We discuss the possible effects of fetal intervention in cases of obstructive uropathy and the postnatal risks associated with it.

Neonatal urinary tract infections: analysis of the patients and recurrences

BACKGROUND

Early diagnosis and proper treatment, including long-term follow up, are very important for neonatal urinary tract infections (UTI).

METHODS

The present study reports the analysis and long-term follow-up results of 71 newborns treated for UTI.

RESULTS

Forty-one per cent of patients were preterm babies. Suspected sepsis and hyperbilirubinemia were the main presenting features. Community-acquired and nasocomial UTI accounted for 63% and 37% of cases, respectively. The leading causative agents were Escherichia coli for community-acquired UTI and Klebsiella pneumoniae for nasocomial UTI. The urosepsis rate was 5%. Abnormal ultrasonography findings were present in 23% and vesicoureteral reflux was present in 15% of babies. A total of 23% of patients showed renal photopenic areas on dimercaptosuccinic acid scan. The recurrence rate was 28% occurring between 1.5 and 12 months, in particular in the first 6 months. Most of the recurrences developed in patients with no predisposing abnormalities.

CONCLUSION

Pediatric nephrologic follow-up of babies experiencing UTI in the neonatal period is very important to identify the predisposing congenital abnormalities and scarred kidneys, to diagnose and to treat the recurrences earlier.

Pediatric intensive care unit nosocomial infections: epidemiology, sources and solutions

Nosocomial infections in the PICU remain a significant source of morbidity and mortality. The risk of infections in these patients remains high because invasive devices allow organisms to bypass normal host defenses. Additionally, this patient group often has coexisting metabolic or organ system dysfunctions. Antibiotic pressure has led to the development of drug-resistant organisms within the PICU, thereby causing infections that are increasingly difficult to control. The best current approach for preventing PICU infections centers on consistent hand washing between patients, early discontinuation of invasive devices, and appropriate isolation strategies. Insight into the causes and locations of PICU-related infections remains a crucial component in the success of preventive strategies.