Michael Kelsey

Spectrum of bacterial colonization associated with urothelial cells from patients with chronic lower urinary tract symptoms.

ABSTRACT Chronic lower urinary tract symptoms (LUTS), such as urgency and incontinence, are common, especially among the elderly, but their etiology is often obscure. Recent studies of acute urinary tract infections implicated invasion by Escherichia coli into the cytoplasm of urothelial cells, with persistence of long-term bacterial reservoirs, but the role of infection in chronic LUTS is unknown. We conducted a large prospective study with eligible patients with LUTS and controls over a 3-year period, comparing routine urine cultures of planktonic bacteria with cultures of shed urothelial cells concentrated in centrifuged urinary sediments. This comparison revealed large numbers of bacteria undetected by routine cultures. Next, we typed the bacterial species cultured from patient and control sediments under both aerobic and anaerobic conditions, and we found that the two groups had complex but significantly distinct profiles of bacteria associated with their shed bladder epithelial cells. Strikingly, E. coli, the organism most responsible for acute urinary tract infections, was not the only or even the main offending pathogen in this more-chronic condition. Antibiotic protection assays with shed patient cells and in vitro infection studies using patient-derived strains in cell culture suggested that LUTS-associated bacteria are within or extremely closely associated with shed epithelial cells, which explains how routine cultures might fail to detect them. These data have strong implications for the need to rethink our common diagnoses and treatments of chronic urinary tract symptoms.

The Inadequacy of Urinary Dipstick and Microscopy as Surrogate Markers of Urinary Tract Infection in Urological Outpatients With Lower Urinary Tract Symptoms Without Acute Frequency and Dysuria

PURPOSE Diagnosing urinary infection in patients with chronic lower urinary tract symptoms without dysuria is a critical step. In this study we scrutinize the sensitivity and specificity of dipstick urinalysis and microscopic pyuria (10 or more white blood cells per microl) to identify infection in such patients. MATERIALS AND METHODS This was a prospective, blinded, observational cohort study of urological outpatients with painless lower urinary tract symptoms. Midstream and catheter urine samples were analyzed. A total of 508 midstream urine samples were used to compare leukocyte esterase, nitrite dipstick and urine microscopy with cultures seeking 10(5) cfu/ml. Similarly 470 catheter urine samples were used to compare the same surrogates with 10(5) cfu/ml and with an enhanced culture method seeking 10(2) cfu/ml. A comparison of leukocyte esterase against microscopic pyuria was made using the 508 midstream and 470 catheter specimens of urine. Midstream urine specimens were provided by 42 normal volunteers for comparison. RESULTS For a midstream urine culture at 10(5) cfu/ml leukocyte esterase was 56% sensitive, nitrite was 10% sensitive and microscopic pyuria was 56% sensitive. Specificities were 66%, 99% and 72%, respectively. For a catheter specimen of urine culture at 10(5) cfu/ml leukocyte esterase was 59% sensitive, nitrite was 20% sensitive and microscopic pyuria was 66% sensitive. Specificities were 84%, 97% and 73%, respectively. The enhanced culture of catheter specimen of urine at 10(2) cfu/ml was positive in 29% of patients vs 15% at 10(5) cfu/ml. CONCLUSIONS Despite official guidelines and widespread use these tests cannot be considered appropriate for diagnosing urinary tract infection in patients with lower urinary tract symptoms, and should be abandoned in this context.

Discrediting microscopic pyuria and leucocyte esterase as diagnostic surrogates for infection in patients with lower urinary tract symptoms: Results from a clinical and laboratory evaluation

Microscopic pyuria is widely used as a surrogate marker of infection, although there is little data supporting its use in patients who present with non‐acute LUTS. The effects of urinary storage, preservation, and the use of laboratory methods to enhance leucocyte detection, are also unclear. This large, prospective study highlights the poor performance of dipstick urine analysis, and direct microscopy, as surrogate markers of UTI in patients with LUTS. A series of laboratory analyses also examine the effects of urine handling and processing on test integrity, which have important implications for clinical practice.

Enterococcus faecalis subverts and invades the host urothelium in patients with chronic urinary tract infection.

Bacterial urinary tract infections (UTI) are a major growing concern worldwide. Uropathogenic Escherichia coli has been shown to invade the urothelium during acute UTI in mice and humans, forming intracellular reservoirs that can evade antibiotics and the immune response, allowing recurrence at a later date. Other bacterial species, such as Staphylococcus saprophyticus, Klebsiella pneumonia and Salmonella enterica have also been shown to be invasive in acute UTI. However, the role of intracellular infection in chronic UTI causing more subtle lower urinary tract symptoms (LUTS), a particular problem in the elderly population, is poorly understood. Moreover, the species of bacteria involved remains largely unknown. A previous study of a large cohort of non-acute LUTS patients found that Enterococcus faecalis was frequently found in urine specimens. E. faecalis accounts for a significant proportion of chronic bladder infections worldwide, although the invasive lifestyle of this uropathogen has yet to be reported. Here, we wanted to explore this question in more detail. We harvested urothelial cells shed in response to inflammation and, using advanced imaging techniques, inspected them for signs of bacterial pathology and invasion. We found strong evidence of intracellular E. faecalis harboured within urothelial cells shed from the bladder of LUTS patients. Furthermore, using a culture model system, these patient-isolated strains of E. faecalis were able to invade a transitional carcinoma cell line. In contrast, we found no evidence of cellular invasion by E. coli in the patient cells or the culture model system. Our data show that E. faecalis is highly competent to invade in this context; therefore, these results have implications for both the diagnosis and treatment of chronic LUTS.

Pseudomonas in augmented care: should we worry?

The problem of Pseudomonas as a nosocomial pathogen is not new, with some authors dating its onset to the start of the antimicrobial era, although other factors, such as the growth of intensive or augmented care, have a part to play. This paper outlines the historical and environmental issues that may be associated with a potential increase in the incidence of this difficult-to-treat pathogen.

Comment on: Spondylodiscitis: update on diagnosis and management

References 1 Cooreman S, Jeurissen A. Comment on: Newer antibacterial agents and their potential role in cystic fibrosis pulmonary exacerbation management. J Antimicrob Chemother 2011; 66: 1195–6. 2 Parkins MD, Elborn JS. Newer antibacterial agents and their potential role in cystic fibrosis pulmonary exacerbation management. J Antimicrob Chemother 2010; 65: 1853–61. 3 Hansen CR, Pressler T, Hoiby N. Early aggressive eradication therapy for intermittent Pseudomonas aeruginosa airway colonization in cystic fibrosis patients: 15 years experience. J Cyst Fibros 2008; 7: 523–30. 4 Lebecque P, Leal T, Zylberberg K et al. Towards zero prevalence of chronic Pseudomonas aeruginosa infection in children with cystic fibrosis. J Cyst Fibros 2006; 5: 237–44. 5 FDA Drug Safety Communication: Increased risk of death with Tygacil (tigecycline) compared to other antibiotics used to treat similar infections. http://www.fda.gov/Drugs/DrugSafety/ucm224370.htm (24 January 2011, date last accessed).

Neonatal resuscitation equipment: A hidden risk for our babies?

Neonatal infections carry a heavy burden of morbidity and mortality. Poor practice can result in unintentional colonisation of medical equipment with potentially pathogenic organisms. This study will determine the prevalence and type of bacterial contamination on exposed neonatal resuscitation equipment in different clinical settings and explore simple measures to reduce contamination risk.

G398(P) Neonatal resuscitation equipment: A hidden risk for our babies?

Aim Neonatal infections carry a heavy burden of morbidity and mortality. Poor practice can result in unintentional colonisation of medical equipment with potentially pathogenic organisms. This study will determine the prevalence and type of bacterial contamination on exposed neonatal resuscitation equipment in different clinical settings and explore simple measures to reduce contamination risk. Methods A survey determined the rates of resuscitation equipment usage. All environmentally-exposed items were identified on resuscitaires hospital-wide and swabbed for bacterial contamination. A new cleaning and storage policy was implemented and the prevalence of environmentally-exposed equipment re-measured post-intervention. Results Resuscitation equipment was used in 28% of neonatal deliveries. Bacterial colony forming units were present on 44% of the 236 exposed equipment pieces swabbed. There was no significant difference in contamination rates between equipment types. Coagulase negative staphylococcus was the most prevalent species (59 pieces, 25%) followed by Escherichia coli and Enterobacter cloacae (20 pieces, 9% each). Opened items stored inside plastic remained sterile, whilst those in low-use areas had significantly less contamination than those in high-use areas (22% vs 51%, P < 0.05). Implementing a simple educational program led to a significant reduction in environmentally-exposed equipment (79% reduction, P < 0.01). Conclusions Pathogenic bacteria can colonise commonly used pieces of neonatal resuscitation equipment. Whilst the clinical significance remains uncertain, equipment should be kept packaged until required and discarded once open, even if unused. Standardising cleaning policies result in rapid and significant improvements in equipment storage conditions, reducing microbial colonisation opportunities.