Antiseptic Efficacy of Povidone Iodine and Chlorhexidine Gluconate Skin Preparation Solutions Used in Burns Surgery.

The authors devised a comparative prospective study to determine the in vitro microbicidal efficacy of skin preparation solutions in the concentrations and temperatures used in the burns theatre against common bacterial and fungal microorganisms. A panel of 10 microorganisms Staphylococcus aureus, streptococcus pyogenes, enterococcus faecalis, escherichia coli, pseudomonas aeruginosa, candida albicans, bacillus cereus were assembled comprising 8 common strains of S. aureus (including methicillin resistant staphylococcus aureus (MRSA)), S. pyogenes, E. faecalis, E. coli, P. aeruginosa, C. albicans, B. cereus, and multi-drug resistant Klebsiella and Acinetobacter. These were cultured in the following formulations: 1) povidone iodine (PVP-iodine) 10% stored at room temperature (250C), 2) PVP-iodine stored at 40 to 420C, 3) chlorhexidine digluconate stored at room temperature diluted with warmed saline to concentrations of 4%, 2%, 1%, 0.8%, and 0.5%. All 3 formulations met DIN EN (Deutsches Institut für Normung) (European Standards) requirements for antiseptics. Both antiseptics showed the same high bactericidal and fungicidal efficacy (P = < 0.05). For chlorhexidine, all minimum inhibitory concentrations at both 24 and 48 hours were very low (< 0.5mg/L), but for PVP-iodine the minimum inhibitory concentrations were much higher and ranged from 64 to 512 mg/L. All concentrations of chlorhexidine tested were superior to PVP-iodine with no bacterial growth. There was a small amount of growth in some of the PVP-iodine treated groups, but this was not clinically significant.

A three-point time series study of antibiotic usage on an intensive care unit, following an antibiotic stewardship programme, after an outbreak of multi-resistant Acinetobacter baumannii.

Antibiotic use in intensive care units (ICUs) can promote antimicrobial resistance. Outbreaks of multi-resistant bacteria significantly affect patient outcomes and delivery of care. Antibiotic stewardship programmes (ASPs), combining root-cause analyses and multi-faceted prevention strategies, are necessary, often at significant cost and time. Which elements of such strategies have the largest impact on antibiotic usage following an outbreak is unclear. The aim of this study was to investigate how antibiotic usage in a university hospital ICU changed with a non-protocolised ASP following a disruptive outbreak of multi-resistant Acinetobacter baumannii (MRAB). This was a three time-period observational cohort study. The primary endpoint was the change in overall antibiotic usage (daily defined dose, DDD, antibiotic-days, antibiotic-courses) for consecutive ICU patients staying >48 h, over three 6-month study time periods pre-MRAB (2008, n = 84) and post-MRAB (2010, n = 88; 2012, n = 122). Secondary endpoints were changes in antibiotic usage and patient demographics, in predefined admission categories (Medical Emergency, ME; Surgical Elective, SEL; and Surgical Emergency, SE). The mean age (54.6 ± 17.7, 58.1 ± 17.9, 62.8 ± 19.1 years*) and severity of illness (APACHE 14.8 ± 8.0, 16.7 ± 6.8, 18.3 ± 6.1*) increased, particularly medical admissions. There was a sustained reduction in DDD antibiotic usage [1895.1 (2008), 1224.2 (2010), 1236.6 (2012) per 1000 patient-days] but no overall change in antibiotic-days or antibiotic-courses. Antibiotic usage (antibiotic-days) fell significantly in surgical emergency admissions [20.2 ± 32.1, 4.6 ± 7.4*, 5.9 ± 7.3]. There was a sustained drop in beta-lactam, quinolone, glycopeptide and macrolide usage. Following an MRAB outbreak, and subsequent operational changes including enhanced ASPs (non-protocolised), there was a sustained overall fall in antibiotic usage in spite of an increase in disease severity over 5 years.

A five-year review of necrotising fasciitis in a tertiary referral unit.

INTRODUCTION: Necrotising fasciitis is a life-threatening illness that is often difficult to diagnose. Immediate debridement and intravenous antibiotic therapy are required to limit the spread of infection. This five-year audit aimed to review the number and outcomes of all cases of necrotising fasciitis admitted to a tertiary referral unit and to assess the validity of the Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) scoring system. METHODS: A retrospective analysis of patient notes over the five-year period from October 2006 to October 2011 was undertaken. The LRINEC score was calculated for each patient to evaluate its usefulness. RESULTS: Overall, 15 patients were diagnosed with necrotising fasciitis. Three patients died. The median age of patients was 51.0 years (range: 34-76 years). There were no obvious predisposing factors in 8 cases but patients had a median of 2.0 co-morbidities. The most common infective agent, present in five patients, was Group A Streptococcus. Other monomicrobial agents included Group G Streptococcus and Klebsiella pneumoniae. Polymicrobial infections were less common than mono-microbial infections and two patients had a polymicrobial infection including methicillin-resistant Staphylococcus aureus. Although the LRINEC scoring system identified 12 of the 15 patients as having a high or intermediate likelihood of necrotising fasciitis, 3 were classified as low likelihood. CONCLUSIONS: This limited case series strongly suggests that the LRINEC system is too insensitive for diagnosis.

Rectal chlamydia--a reservoir of undiagnosed infection in men who have sex with men.

OBJECTIVE: To determine the prevalence of rectal chlamydia infection in a cohort of men who have sex with men (MSM) and the proportion of infection that would be missed without routine screening. METHODS: MSM presenting to four HIV/GUM outpatient clinics at the Chelsea & Westminster Hospital NHS Foundation Trust between 1 November 2005 and 29 September 2006 were offered testing for rectal chlamydia infection in addition to their routine screen for sexually transmitted infections (STIs). Chlamydia trachomatis (CT) tests were performed using the Beckton-Dickinson Probe-Tec Strand Displacement Assay. Positive samples were re-tested at the Sexually Transmitted Bacteria Reference Laboratory, to confirm the result and identify lymphogranuloma venereum (LGV)-associated serovars. RESULTS: A total of 3076 men were screened. We found an 8.2% prevalence of infection with CT (LGV and non-LGV serovars) in the rectum and 5.4% in the urethra. The HIV and rectal chlamydia co-infection rate was 38.1%. The majority of rectal infections (69.2%, (171/247)) were asymptomatic and would have been missed if routine screening had not been undertaken. Of the samples re-tested, 94.2% (227/242) rectal and 91.8% (79/86) urethral specimens were confirmed CT positive and 36 cases of LGV were identified. CONCLUSION: Our data show a high rate of rectal chlamydia infection, in the majority of cases it was asymptomatic. We recommend routine screening for rectal chlamydia in men at risk, as this may represent an important reservoir for the onward transmission of infection.

The effect of alcohol swabs and filter straws on reducing contamination of glass ampoules used for neuroaxial injections.

We have investigated the incidence of contamination of the contents of glass ampoules used for neuraxial injections, and whether this was reduced by wiping the outsides of the ampoules with isopropyl alcohol or using a filter straw. One hundred fentanyl and diamorphine ampoules used for routine regional anaesthesia were either wiped or not wiped with alcohol before their contents were aspirated, and the residual contents were swabbed and incubated. None of the swabs from the wiped ampoules grew organisms compared with nine (18%) from non-wiped ampoules (p = 0.004). In a second, laboratory study, 100 glass ampoules of saline were coated with Staphylococcus aureus and divided into four groups: wiped/not wiped with alcohol and with/without a filter straw. The contents of the ampoules were aspirated; the remnants and the aspirate were swabbed and incubated as before. Most contamination occurred in the unwiped groups and although numbers were small, filtering appeared to reduce contamination further. As filter straws also reduce the risk of injecting glass particles (even if not contaminated), our results suggest that wiping glass ampoules with isopropyl alcohol and using a filter straw should be part of routine practice when performing regional anaesthesia.

Increasing detection of asymptomatic syphilis in HIV patients.

BACKGROUND/OBJECTIVES: The burden of new syphilis diagnoses in London has mainly been in men who have sex with men (MSM), many of whom are co-infected with HIV. Our HIV unit introduced regular serological screening for syphilis during routine follow up care to detect patients who may be at risk of asymptomatic infection. We assessed if this remained an effective and necessary strategy in the second year since introduction. METHODS: All HIV outpatients with newly positive syphilis serology between 1 May 2002 and 30 April 2003 were identified using a prospectively collected database. Only patients who were asymptomatic at the time of screening were included (cohort B). They were compared to patients in the exact preceding year (cohort A). RESULTS: 2655 patients had at least one CD4 count measured in the period (surrogate marker for patients having routine follow up bloods), of whom 2389 (90%) had syphilis serology performed. 40 individuals were found to have early asymptomatic infection (two were re-infections), compared to 26 patients in cohort A. These 40 patients represented 36% of all patients with infectious syphilis treated within our department and 56% of those who were HIV positive. The event rate in cohort B was 7.3 per 1000 patient years (CI 5.2 to 9.9) compared to 2.8 (CI 1.8 to 4.0) in cohort A. CONCLUSION: Routine screening is effective and has detected increasing numbers of HIV outpatients with early asymptomatic syphilis. Our department will continue this strategy for all HIV patients during their follow up care. We recommend that other units adopt similar initiatives that assist with regional control of the UK syphilis epidemic.

Is increased surveillance for asymptomatic syphilis in an HIV outpatient department worthwhile?

OBJECTIVES: Syphilis outbreaks have recently been reported in the United Kingdom, some of which have included cohorts of HIV positive individuals. As a result we commenced 3 monthly screening of syphilis serology (STS) for HIV positive patients having routine follow up blood tests. We assessed if there was an increased number of individuals being screened and also whether the screening programme was diagnosing early cases of syphilis. METHODS: Data from a 1 year period following introduction of screening (May 2001) were analysed and compared with data from the same period last year. The case notes of patients with a positive VDRL were reviewed to establish, firstly, whether these represented new diagnoses and, secondly, whether patients were asymptomatic at the time of screening. RESULTS: 2670 patients had at least one CD4 count measured in the period (surrogate for patients having routine bloods). Of these, 2266 patients had STS performed (85%). 38 patients had a positive VDRL. Of these, 20 were confirmed as having early syphilis which was asymptomatic at the time of screening. Six asymptomatic cases were also confirmed with newly positive TPPAs and a negative VDRL. These 26 asymptomatic cases represent 29% of all cases of early syphilis diagnosed in our department and 50% of cases in the HIV positive cohort. CONCLUSION: With intensive surveillance significant numbers of cases of asymptomatic early syphilis are being identified in a group of HIV individuals under routine follow up, at an earlier stage than would otherwise have been the case. This presents an opportunity to intervene not only to prevent clinical illness but also to institute infection control measures.

The impact of Acinetobacter baumannii in the intensive care unit.

Acinetobacter baumannii is a significant problem in critically ill patients. It is widespread, can colonise patients quickly and causes virulent infections. However, its overall impact on morbidity and mortality in the critically ill remains unmeasured. This study was designed to investigate A. baumannii colonisation and infection rates in a critically ill population over an 18-month period. Twenty-seven patients from a population of 347 were identified as having A. baumannii. Sixteen were colonised, whereas 11 were infected. Eleven of the 27 patients with A. baumannii died (41%). Of these, eight were colonised and three were infected. In the same period, 320 patients did not have A. baumannii and their mortality rate was 20% (n = 64). The mortality rate of patients with A. baumannii was significantly higher than that of patients without infection.

Pneumonia due to antibiotic resistant Streptococcus pneumoniae and Pseudomonas aeruginosa in the HAART era.

Antibiotic resistance profiles are useful in directing therapeutic strategies during bacterial infections. Patterns of antimicrobial resistance in Streptococcus pneumoniae and Pseudomonas aeruginosa associated pneumonia were investigated in an HIV-1 infected cohort during the era of highly active antiretroviral therapy. The median CD4 count at presentation was significantly lower for cases of P aeruginosa than for S pneumoniae. However, the number of antibiotic resistant cases of P aeruginosa decreased throughout the study period, while the incidence of S pneumoniae remained unchanged. In contrast to pneumococcal pneumonia, we show that antiretrovirals have protected from pneumonia due to antibiotic resistant P aeruginosa. These findings have implications for the treatment of individuals presenting with serious infections in which antibiotic therapy needs to be instituted before identification and sensitivities are known.

Comparison of bacterial colonization rates of antiseptic impregnated and pure polymer central venous catheters in the critically ill.

A study was performed on critically ill patients to evaluate the rate of colonization and catheter-related sepsis using antiseptic bonded (Arrowguard Arrow International) versus smooth pure polymer (Infectguard MedexMedical Ltd) central venous catheters. Two hundred and thirty-two catheters were inserted into 181 patients. Indications for removal included local or systemic infection, the catheter was no longer required and patient death. No statistical difference in colonization rate was found between the two types of catheter.

MRSA in the critically ill.

MRSA colonization and infection rates were prospectively examined over an 18 month period in a general Intensive Care Unit. Of 642 admissions, 305 were in ICU for longer than 48 h and were hence included and a further three patients were already colonized at admission but stayed less than 48 h. Ninety-seven patients were colonized with MRSA including 19 who were already colonized at admission. There were 56 episodes of clinical infection in 43 patients. The mortality rates in the colonized and infected groups, were 14.8% and 16.2% respectively, while the rate in those not colonized was 23%. These figures were not statistically different. Those colonized or infected with MRSA had significantly longer ICU stays than those not colonized. Sputum colonization and infection was a major site for MRSA. There was diagnostic certainty of MRSA infection in 40% of cases emphasizing the difficulty in diagnosis of infection due to MRSA in the critically ill. Both colonization and infection with MRSA are associated with longer ICU stay but do not appear to influence mortality.

Clostridium difficile infection, hospital geography and time-space clustering.

To analyse spatial and temporal relationships of Clostridium difficile-associated disease in an inner-city hospital, we retrospectively evaluated 283 episodes of confirmed C. difficile diarrhoea in the Chelsea and Westminster Hospital between 1995 and 1998, against a background of relatively stable case mix, antibiotic usage and admission numbers, using Knox analysis to determine the presence of disease clustering in time and space. We found five time-space clusters on four medical wards and between two adjacent units. The clusters were not related to the overall case number on single wards, and were separated in time. Knox time-space analysis provides a simple screening tool to identify disease clusters, assess the efficacy of infection control measures and the influence of hospital geography and traffic. The results support the importance of infection control measures in the prevention of C. difficile-related disease.

Initial treatment of peritoneal dialysis peritonitis without vancomycin with a once-daily cefazolin-based regimen.

To reduce the use of vancomycin, the current recommendations of the International Society of Peritoneal Dialysis (PD) for the initial treatment of peritonitis complicating PD are to administer intraperitoneal (IP) cefazolin or cephalothin in every PD fluid bag, together with once-daily gentamicin. In view of the inherent impracticalities of this regimen, we studied the efficacy of once-daily cefazolin (1.5 g) IP with gentamicin IP as initial treatment for primary (nonrecurrent) PD peritonitis. This regimen has been used in all episodes of peritonitis not associated with tunnel or exit-site infections or fluid leaks. Sixty-nine episodes in 61 patients were analyzed (44 patients, continuous ambulatory PD; 22 patients, automated PD; and 3 patients, hospital-based intermittent PD), of which 38 episodes (55%) were gram-positive infections, 6 episodes (9%) were gram-negative infections, and 18 episodes (26%) had negative culture results. Four patients died within 4 weeks of infection (none considered attributable to inadequate treatment of their peritonitis). Ten catheters (14.5%) required removal to clear the infection; 7 catheters were in patients with gram-negative infections. The relapse rate within 4 weeks of ceasing antibiotic therapy was 8.9%. Compared with the results of 40 episodes of peritonitis treated initially with our previous IP vancomycin and gentamicin regimen, successful treatment (no death, catheter removal, or recurrence) was achieved in 52 of 69 episodes in the cefazolin group (75.4%) versus 23 of 40 episodes in the vancomycin group (57.5%; P: = 0.058). In conclusion, once-daily IP cefazolin and gentamicin for the initial treatment of PD peritonitis is at least as effective as a vancomycin-based regimen and is well tolerated.

Central venous blood culture: a useful test for catheter colonisation?

OBJECTIVE: To evaluate the widespread practice of using qualitative culture of venous blood taken through central venous catheters (CVCs) as a means of diagnosing catheter colonisation in situ. DESIGN: A prospective clinical study. PATIENTS: Three hundred fifty-one CVCs were inserted into 228 critically ill patients. INTERVENTIONS: Prior to CVC removal, blood was taken for qualitative culture from the CVC and a peripheral site. All catheter tips underwent semi-quantitative analysis of bacterial colony count [1]. MEASUREMENTS AND RESULTS: One hundred eighteen (33.6%) CVCs were found to be colonised on removal. A positive central blood culture had a sensitivity and specificity of 50.8% and 78.9% when compared with the 'gold standard' of catheter tip culture. This gives a positive predictive value of 47.7% and a negative predictive value of 76.5%. The sensitivity and specificity of a positive peripheral blood culture were 41.5% and 77.7% with positive and negative predictive values of 48.8% and 72.9%, respectively. When only those catheters removed because of systemic sepsis (n = 139) were considered, a positive central blood culture had a sensitivity of 58.8% and a specificity of 69.3%. CONCLUSION: Our results indicate that the use of central blood culture confers a small advantage in sensitivity compared with peripheral blood culture. This advantage was further improved by only considering the catheters removed because of systemic sepsis but at the cost of a loss of specificity. Qualitative blood culture is a poor tool for the diagnosis of in-situ CVC colonisation.