Clinical predictors of methicillin-resistance and their impact on mortality associated with Staphylococcus aureus bacteraemia.

We investigated the clinical predictors of methicillin-resistance and their impact on mortality in 371 patients with Staphylococcus aureus bacteraemia identified from two prospective multi-centre studies. Methicillin resistant S. aureus (MRSA) accounted for 42.2% of community-onset and 74.5% of hospital-onset cases. No significant clinical difference was found between patients infected with MRSA vs. methicillin-sensitive S. aureus (MSSA), except that the former were more likely to have had hospital-onset bacteraemia and received antibiotics in the preceding 90 days. After stratifying according to the acquisition site, prior antibiotic use was the only independent predictor of having MRSA in both community-onset and hospital-onset cases. The frequency of inappropriate empirical antibiotic therapy was higher in patients with MRSA than in those with MSSA bacteraemia. However, methicillin resistance was not a predictor of mortality in patients and the clinical characteristics and outcomes of both MRSA and MSSA bacteraemia were similar. This study indicates that there are no definitive clinical or epidemiological risk factors which could distinguish MRSA from MSSA cases with the exception of the previous use of antibiotics for having MRSA bacteraemia, which emphasises the prudent use of glycopeptide treatment of patients at risk for invasive MRSA infections.

The effect of concomitant use of systemic antibiotics in patients with Clostridium difficile infection receiving metronidazole therapy.

Management of Clostridium difficile infection (CDI) involves discontinuation of the offending antibiotic agent as soon as possible. However, the ongoing infection does not allow discontinuation of the offending antibiotic. We aimed to retrospectively investigate the predictors of treatment failure and impact of the concomitant use of systemic antibiotics in patients receiving metronidazole therapy. This study was conducted among patients hospitalised at a second care academic hospital from January 2013 to December 2014. Eligible patients were identified by reviewing stool toxin enzyme immunoassay results for C. difficile. Diarrhoea was defined as the passage of at least three loose or watery stools within 24 h. Among 314 patients with CDI receiving metronidazole therapy, 62 (19.7%) showed treatment failure and 105 (33.4%) received concomitant antibiotics. Underlying dialysis, fever >38.3 °C, low median serum albumin levels and concomitant use of antibiotics were independent predictors of treatment failure in patients with CDI receiving metronidazole therapy. The concomitant use of antibiotics increased the rates of treatment failure and 30-day mortality in patients receiving metronidazole therapy. These results suggest that metronidazole should be used in mild cases of CDI only after discontinuation of the offending antibiotics.

Surveillance of the Middle East respiratory syndrome (MERS) coronavirus (CoV) infection in healthcare workers after contact with confirmed MERS patients: incidence and risk factors of MERS-CoV seropositivity.

Given the mode of transmission of Middle East respiratory syndrome (MERS), healthcare workers (HCWs) in contact with MERS patients are expected to be at risk of MERS infections. We evaluated the prevalence of MERS coronavirus (CoV) immunoglobulin (Ig) G in HCWs exposed to MERS patients and calculated the incidence of MERS-affected cases in HCWs. We enrolled HCWs from hospitals where confirmed MERS patients had visited. Serum was collected 4 to 6 weeks after the last contact with a confirmed MERS patient. We performed an enzyme-linked immunosorbent assay (ELISA) to screen for the presence of MERS-CoV IgG and an indirect immunofluorescence test (IIFT) to confirm MERS-CoV IgG. We used a questionnaire to collect information regarding the exposure. We calculated the incidence of MERS-affected cases by dividing the sum of PCR-confirmed and serology-confirmed cases by the number of exposed HCWs in participating hospitals. In total, 1169 HCWs in 31 hospitals had contact with 114 MERS patients, and among the HCWs, 15 were PCR-confirmed MERS cases in study hospitals. Serologic analysis was performed for 737 participants. ELISA was positive in five participants and borderline for seven. IIFT was positive for two (0.3%) of these 12 participants. Among the participants who did not use appropriate personal protective equipment (PPE), seropositivity was 0.7% (2/294) compared to 0% (0/443) in cases with appropriate PPE use. The incidence of MERS infection in HCWs was 1.5% (17/1169). The seroprevalence of MERS-CoV IgG among HCWs was higher among participants who did not use appropriate PPE.

Predictors of uropathogens other than Escherichia coli in patients with community-onset acute pyelonephritis.

AIM: A constant reduction in the incidence of community-onset acute pyelonephritis (CO-APN) caused by Escherichia coli has been shown with a parallel increase incidence caused by other organisms. Therefore, we evaluated the risk factors and outcome of non-E. coli as uropathogens in patients with community-onset APN. METHODS: As a part of a nationwide multicentre surveillance study conducted in Korea, a total of 416 patients with CO-APN were collected with their epidemiological, antibiotic treatment and outcome data. RESULTS: The risk factors and outcomes of non-E. coli as uropathogens were evaluated in a total of 416 patients with culture-confirmed CO-APN. Non-E. coli caused 127 cases (30.5%) of CO-APN. CO-APN caused by non-E. coli resulted in higher inappropriate empirical therapy (38.6% vs. 20.1%, p < 0.001), longer hospital stay (12.6 days vs. 6.7 days, p = 0.005) and higher 30-day mortality (9.4% vs. 3.8% p = 0.020) compared with CO-APN caused by E. coli. Multivariate analyses showed that male gender (OR, 3.48; CI, 2.13-5.67; p < 0.001), underlying haematological disease (OR, 5.32; CI, 1.17-24.254; p = 0.031), underlying benign prostate hyperplasia (OR, 2.61; CI, 1.02-6.74; p = 0.046), chronic indwelling urethral catheter (OR, 6.34; CI, 1.26-31.84; p = 0.025) and admission history in the previous 6 months (OR, 2.12; CI, 1.23-3.58; p = 0.005) were predictors for CO-APN caused by a non-E. coli isolate. CONCLUSIONS: Community-onset APN caused by non-E. coli represents a distinct subset of urinary tract infections with worse outcomes. The defined risk factors related with non-E. coli should be taken into consideration when empirical antibiotic therapy is prescribed in patients with community-onset APN.

Serum albumin level as a predictor of intensive respiratory or vasopressor support in influenza A (H1N1) virus infection.

AIM: Low serum albumin levels occur in a variety of disease states and are related to in-hospital mortality and length of stay. The purpose of this study was to evaluate the association of commonly measured biochemical markers in critically ill patients such as serum albumin or C-reactive protein (CRP) with the need for intensive respiratory or vasopressor support (IRVS) in patients with 2009 influenza A (H1N1). METHODS: A total of 104 patients from an H1N1 registry database of 2436 patients were enrolled. Clinical characteristics and laboratory findings within 24 h of admission were reviewed to evaluate whether serum biochemical markers can be used as predictors of illness severity in adult patients with H1N1 based on the need for IRVS. RESULTS: Twenty-four (23.1%) of the 104 patients enrolled in the study received IRVS during the study period. Independent predictors of the need IRVS were serum glucose level on admission (OR 1.02; 95% CI 1.00-1.04; p = 0.021) and serum albumin level on admission (OR 0.12; 95% CI 0.02-0.63; p = 0.013). The diagnostic sensitivity of albumin levels for predicting the need for IRVS in patients with confirmed H1N1 with a cut-off value of 2.7 g/dl was 79.17% (95% CI 57.8-92.9), the specificity was 85.71% (95% CI 75.9-92.6), the positive predictive value was 63.3% (95% CI 43.9-80.1) and the negative predictive value was 93.0% (95% CI 84.3-97.7). The area under the receiver operation characteristic curve was 0.860 (95% CI 0.773-0.923) for albumin, 0.808 (95% CI 0.713-0.882) for glucose and 0.734 (95% CI 0.633-0.821) for CRP. CONCLUSIONS: Serum albumin levels and glucose levels on admission were predictors of the need IRVS in adult patients with H1N1. Based on these findings, the level of albumin at presentation may serve as a novel and simple early biomarker to identify patients at high risk for a complicated clinical course of disease.

Tacrolimus as a risk factor for tuberculosis and outcome of treatment with rifampicin in solid organ transplant recipients.

BACKGROUND: The purpose of this study was to investigate the incidence, risk factors, and treatment outcome of tuberculosis (TB) in solid organ transplant (SOT) recipients treated with rifampicin. METHODS: The incidence density of TB was calculated by a retrospective cohort study. Risk factors for TB were analyzed by a nested case-control study. Treatment outcome and effects of anti-TB drugs on immunosuppressants and allograft were compared between patients whose initial 2-month intensive regimen included rifampicin and those whose intensive regimen did not. RESULTS: Among the 2144 SOT recipients over 16 years, 40 cases of TB were found (1.7%). The incidence density was 372 cases per 10(5) patient years (95% confidence interval [CI], 270-503), which was 4 times higher than for the general Korean population (90 cases per 10(5) person years). The median time to the development of TB was 234 days (range, 33-3940 days). The use of tacrolimus (odds ratio [OR] 4.90; 95% CI, 1.74-13.80; P = 0.003) and cytomegalovirus (CMV) infection within the prior 3 months (OR 4.62; 95% CI, 1.44-14.87; P = 0.01) were found to be risk factors for TB. Patients whose intensive regimen included rifampicin were more likely to have an increased dose of calcineurin inhibitors than patients whose intensive regimen did not include rifampicin (13/15 [86.7%] vs. 3/14 [21.4%], P = 0.001). Graft rejection and mortality did not differ between the 2 groups. CONCLUSIONS: Use of tacrolimus and CMV infection were major risk factors for TB in SOT recipients. The graft outcome and mortality did not differ whether rifampicin was used or not during the first 2-month intensive phase.

Impact of inappropriate empiric antimicrobial therapy on outcome in Pseudomonas aeruginosa bacteraemia: a stratified analysis according to sites of infection.

BACKGROUND: The purpose of this study was to evaluate the impact of inappropriate empiric antimicrobial therapy on the outcome of Pseudomonas aeruginosa bacteraemia according to the primary infection site. METHODS: A retrospective cohort study including 202 patients with P. aeruginosa bacteraemia was performed. High-risk sites of infection were defined as the lung, intra-abdominal non-hepatobiliary tract or unknown source. RESULTS: Of the 202 patients with P. aeruginosa bacteraemia, 80 (39.6%) had received inappropriate empiric antimicrobial therapy. No significant difference in the 30-day mortality rate was found between the inappropriate therapy group and the appropriate therapy group (19/80 [23.8%] vs. 32/122 [26.2%], P = 0.692). Patients with pneumonia or non-hepatobiliary tract intra-abdominal infection showed significant association with high mortality, while those with urinary tract or hepatobiliary tract infection showed negative associations with mortality. In the subgroup analysis including 98 patients with high-risk sites of infection, the mortality rate of the inappropriate therapy group was significantly higher than that of the appropriate therapy group (14/26 [53.8%] vs. 23/72 [31.9%], P = 0.035). Inappropriate empiric antimicrobial therapy was also found to be one of the independent risk factors for mortality in patients with high-risk sites of infection (odds ratio [OR] 8.69; 95% confidence interval [CI] 1.86-40.59), along with renal disease, corticosteroid use, polymicrobial infection and higher Pitt bacteraemia score. CONCLUSION: Inappropriate empiric antimicrobial therapy adversely affected the outcome of P. aeruginosa bacteraemia in patients with high-risk sites of infection. Our data suggest that the impact of inappropriate antimicrobial therapy on the outcome of P. aeruginosa bacteraemia may be dependent on the primary site of infection.

Risk factors for treatment failure in patients with prosthetic joint infections.

A retrospective, observational cohort study was conducted to describe the incidence, clinical and microbiological findings and to evaluate risk factors for treatment failure associated with prosthetic joint infections (PJIs). We retrospectively reviewed the medical records of all patients undergoing total knee or total hip prosthesis implantation in our institution between 1994 and 2008. Our institution is a 1950-bed tertiary care university hospital and referral centre. A total of 93 patients with PJIs was identified although only 68 patients had undergone prosthesis implantation at our hospital. The overall infection rate was 0.63%. The most common organisms isolated were Gram positive (76.5%), including meticillin-resistant staphylococci. Two-stage arthroplasty was performed in 48 (51.6%) patients, and debridement and retention of the prosthesis in 34 (36.5%) patients. When 43 patients followed up for more than two years after treatment were included in treatment outcome analysis, the overall treatment failure rate was 41.8% (18/43). Staphylococcus aureus infection was the only clinical variable associated with treatment failure (odds ratio: 11.9; 95% confidence interval: 1.07-133.9; P=0.044), after adjustment for the other variables. In conclusion, S. aureus was the most common pathogen isolated in patients with PJI, and an independent risk factor for treatment failure in patients with PJI.

Risk factors for treatment failure in patients with prosthetic joint infections.

A retrospective, observational cohort study was conducted to describe the incidence, clinical and microbiological findings and to evaluate risk factors for treatment failure associated with prosthetic joint infections (PJIs). We retrospectively reviewed the medical records of all patients undergoing total knee or total hip prosthesis implantation in our institution between 1994 and 2008. Our institution is a 1950-bed tertiary care university hospital and referral centre. A total of 93 patients with PJIs was identified although only 68 patients had undergone prosthesis implantation at our hospital. The overall infection rate was 0.63%. The most common organisms isolated were Gram positive (76.5%), including meticillin-resistant staphylococci. Two-stage arthroplasty was performed in 48 (51.6%) patients, and debridement and retention of the prosthesis in 34 (36.5%) patients. When 43 patients followed up for more than two years after treatment were included in treatment outcome analysis, the overall treatment failure rate was 41.8% (18/43). Staphylococcus aureus infection was the only clinical variable associated with treatment failure (odds ratio: 11.9; 95% confidence interval: 1.07e133.9; P = 0.044), after adjustment for the other variables. In conclusion, S. aureus was the most common pathogen isolated in patients with PJI, and an independent risk factor for treatment failure in patients with PJI.

Inappropriate initial antimicrobial therapy as a risk factor for mortality in patients with community-onset Pseudomonas aeruginosa bacteraemia.

This study was performed to identify the risk factors for mortality and evaluate the effect of inappropriate initial antimicrobial therapy on the outcomes of patients with community-onset Pseudomonas aeruginosa bacteraemia in an emergency department (ER) setting. All cases with P. aeruginosa bacteraemia occurring within 48 h after ER visit from January 2000 to December 2005 were retrospectively analysed. A total of 106 community-onset P. aeruginosa bacteraemia cases in the ER were included (mean age, 57.61 +/- 14.44 years old; M:F, 58:48). Although P. aeruginosa bacteraemia was diagnosed in the ER, most of the cases of P. aeruginosa bacteraemia were healthcare-associated (88.7%). Malignancy (n = 83, 78.3%) was the most common underlying disorder. Fifty patients (47.2%) were neutropaenic and 56 patients (52.8%) had septic shock. The overall 30-day mortality rate was 26.4% (28/106). In the univariate analysis, underlying malignancy, high Charlson's weighted index of comorbidity (> or = 3), high Pitt bacteraemia score (> or = 4), indwelling central venous catheter and inappropriate initial therapy were significantly associated with 30-day mortality (all P < 0.05). In the multivariate analysis, high Pitt bacteraemia score (OR, 17.03; 95% CI, 4.60-63.15; P < 0.001) and inappropriate initial antimicrobial therapy (OR, 4.29; 95% CI, 1.39-13.24; P = 0.011) were found to be significant risk factors for 30-day mortality. The 30-day mortality rate was significantly higher in the inappropriate therapy group (18/51, 35.3%) than in the appropriate therapy group (10/55, 18.2%) (P = 0.046). This study demonstrated that inappropriate initial antimicrobial therapy was significantly associated with unfavourable outcomes in patients with community-onset P. aeruginosa bacteraemia. As P. aeruginosa bacteraemia can be a fatal infection, even when community-onset, inappropriate antimicrobial therapy should be avoided in suspected cases of P. aeruginosa bacteraemia.