Baek-Nam Kim

Management of meningitis due to antibiotic-resistant Acinetobacter species

Acinetobacter meningitis is becoming an increasingly common clinical entity, especially in the postneurosurgical setting, with mortality from this infection exceeding 15%. Infectious Diseases Society of America guidelines for therapy of postneurosurgical meningitis recommend either ceftazidime or cefepime as empirical coverage against Gram-negative pathogens. However, assessment of the pharmacodynamics of these cephalosporins in cerebrospinal fluid suggests that recommended doses will achieve pharmacodynamic targets against fewer than 10% of contemporary acinetobacter isolates. Thus, these antibiotics are poor options for suspected acinetobacter meningitis. From in vitro and pharmacodynamic perspectives, intravenous meropenem plus intraventricular administration of an aminoglycoside may represent a superior, albeit imperfect, regimen for suspected acinetobacter meningitis. For cases of meningitis due to carbapenem-resistant acinetobacter, use of tigecycline is not recommended on pharmacodynamic grounds. The greatest clinical experience rests with use of polymyxins, although an intravenous polymyxin alone is inadvisable. Combination with an intraventricularly administered antibiotic plus removal of infected neurosurgical hardware appears the therapeutic strategy most likely to succeed in this situation. Unfortunately, limited development of new antibiotics plus the growing threat of multidrug-resistant acinetobacter is likely to increase the problems posed by acinetobacter meningitis in the future.

Bacteraemia Due to Tribe Proteeae: A Review of 132 Cases During a Decade (1991–2000)

To characterize the clinical features of bacteraemia due to tribe Proteeae, 132 cases among 130 patients from 1991 to 2000 were analysed. The organisms included the Proteus species in 63 cases (P. mirabilis in 41, P. penneri in 2 and P. vulgaris in 20), the Providencia species in 8 (P. rettgeri in 3 and P. stuartii 5) and Morganella morganii in 61. Morganella bacteraemia occurred more frequently in the hospital (70.5%). Biliary and hepatic diseases were predominant in cases with Morganella bacteraemia while cardiovascular, urological and neurological diseases were more common in cases with Proteus bacteraemia. Biliary drainage catheters had more frequently been placed in cases with Morganella bacteraemia (39.3%, p<0.001), and urinary catheters more frequently in cases with Proteus bacteraemia (17.5%). Biliary infection was most common in cases with Morganella bacteraemia (49.2%), while urinary tract infection (UTI) was most common in cases with Proteus bacteraemia (47.6%). Mortality directly related to bacteraemia due to tribe Proteeae was 20.8% (22.6, 50.0 and 15.0% for Proteus, Providencia and Morganella bacteraemia, respectively). In conclusion, Morganella bacteraemia was most frequently associated with biliary infection, while Proteus bacteraemia was most frequently with UTI. Providencia bacteraemia was relatively uncommon and it can be associated with infections other than UTI.

Serratia Bacteremia in a Large University Hospital: Trends in Antibiotic Resistance During 10 Years and Implications for Antibiotic Use

OBJECTIVE To identify antibiotic resistance trends and risk factors for resistance of Serratia species to third-generation cephalosporins. DESIGN Retrospective survey of medical records. SETTING A 2,200-bed, tertiary-care hospital. PATIENTS One hundred twenty-two patients with Serratia bacteremia between January 1991 and June 2001. METHODS Infectious disease physicians collected data from medical records regarding patient demographics, underlying disease or condition, portal of entry, microorganism, antibiogram, complications, antibiotics received, and outcome. RESULTS Among 122 Serratia isolates, 117 (95.9%) were Serratia marcescens and 110 (90.2%) were of nosocomial origin. During the study period, the 122 isolates showed a high rate of resistance to third-generation cephalosporins (45.9%) and extended-spectrum penicillins (56.6%). The resistance rate to ciprofloxacin was 32.0%. The resistance rate to third-generation cephalosporins increased from 31.7% for 1991 to 1995 to 54.9% for 1996 to 1998 and 50.0% for 1999 to 2001. In the multivariate analysis, prior use of a second-generation cephalosporin (adjusted odds ratio [OR], 5.90; 95% confidence interval [CI90], 1.41 to 24.6; P = .015) or a third-generation cephalosporin (OR, 3.26; CI95, 1.20 to 8.87; P = .020) was a strong independent risk factor for resistance to third-generation cephalosporins. The overall case-fatality rate was 25.4% (Serratia bacteremia-related case-fatality rate, 13.1%). CONCLUSION Prior use of a second- or third-generation cephalosporin was the most important risk factor for bacteremia with Serratia resistant to third-generation cephalosporins, suggesting the need for antibiotic control. The potential role of patient-to-patient spread could not be fully evaluated in this retrospective study.

Impact of Previous Use of Antibiotics on Development of Resistance to Extended-Spectrum Cephalosporins in Patients with Enterobacter Bacteremia

Abstract.This retrospective study was conducted to determine the risk factors for resistance to extended-spectrum cephalosporins (ESCs) and to examine the influence of previous use of an aminoglycoside with an ESC on resistance to ESCs in patients with Enterobacter bacteremia from January 1991 through December 2000. A total of 423 episodes of Enterobacter bacteremia among 414 patients were documented during the 10-year study period. Three hundred thirty-two (78%) isolates were Enterobacter cloacae, 72 (17%) Enterobacter aerogenes, and 19 (4%) other Enterobacter species. Causative isolates exhibited resistance to ESCs in 225 episodes and susceptibility in 198 episodes. Nosocomial acquisition was an independent risk factor for resistance to ESCs (odds ratio [OR], 3.4; 95% confidence interval [95%CI], 1.7–6.8). The median number of antibiotics used was significantly greater in cases caused by resistant isolates than in cases caused by susceptible isolates (OR, 1.8; 95%CI, 1.2–2.6). Resistance to ESCs was associated with previous use of any ESC (OR, 5.0; 95%CI, 2.5–10.2). The proportion of resistant episodes in patients treated previously with an aminoglycoside plus an ESC was not different from that in patients treated with an ESC alone. In conclusion, previous use of ESCs was associated with resistance to ESCs in patients with Enterobacter bacteremia; moreover, previous use of an aminoglycoside with an ESC did not significantly decrease the risk of resistance to ESCs.

Retrospective analysis of clinical and microbiological aspects of Klebsiella oxytoca bacteremia over a 10-year period

Abstract.From 1991 to 2000, 125 sporadic cases of Klebsiella oxytoca bacteremia were analyzed retrospectively to review clinical features and to identify the risk factors associated with resistance to extended-spectrum cephalosporins and fatal outcome. Bacteremia was acquired nosocomially in 52% of the patients. Almost all patients (97%) had an underlying disease, with biliary and pancreatic disease occurring most frequently (55%). The biliary tract was the most common site of infection (44%). Resistance to extended-spectrum cephalosporins was identified in 22 of the 125 (18%) Klebsiella oxytoca blood isolates and resistance to ciprofloxacin in 9 (7%). Only previous antibiotic therapy was strongly associated with resistance to extended-spectrum cephalosporins in patients with Klebsiella oxytoca bacteremia (P=0.009). The mortality rate was 24% and was higher in patients infected with isolates resistant to extended-spectrum cephalosporins (41% vs. 20%; P=0.04). In multivariate analysis, fatal outcome was independently associated with septic shock, deteriorated mental status, polymicrobial bacteremia, and solid tumor. Surgical therapy had a protective effect (OR, 0.06; 95% CI, 0.005–0.7; P=0.03). In conclusion, Klebsiella oxytoca bacteremia was most commonly associated with biliary tract infection. Previous antibiotic therapy was strongly associated with resistance to extended-spectrum cephalosporins in patients with Klebsiella oxytoca bacteremia.

Resistance to extended-spectrum cephalosporins and mortality in patients with Citrobacter freundii bacteremia.

Abstract.Background: This study was performed to characterize the clinical features and to identify the risk factors for resistance to extended-spectrum cephalosporins (ESCs) and for mortality in patients with Citrobacter freundii bacteremia. Patients and Methods: 105 patients (aged ≥ 15 years) with C. freundii bacteremia in 1991–2000 were retrospectively analyzed. Results: Nosocomial acquisition was identified in 78.1% of the patients. Hepatic, biliary and pancreatic disease was the most common underlying disease (65.7%) and the biliary tract was the most common site of infection (50.5%). The overall resistance rate to ESCs was 59.0% and was significantly associated with hepatic, biliary and pancreatic disease, recent surgery and procedure, biliary drainage catheter and previous antibiotic therapy in univariate analysis. However, only previous antibiotic therapy with ESCs (OR = 5.0, 95% CI 1.6–15.7, p = 0.006) and recent surgery or procedure (OR = 3.1, 95% CI 1.1–8.4, p = 0.03) were strong, independent risk factors in multivariate analysis. Mortality directly related to C. freundii bacteremia was 21.9% and there was no difference between cases with resistance and susceptibility to ESCs (19.4% vs 25.6%; p = 0.45). Mortality was significantly associated with rapidly fatal or ultimately fatal underlying disease, a solid tumor, septic shock and polymicrobial bacteremia in univariate analysis. Among patients who had therapeutic surgical procedures, mortality was lower (4.5%, p = 0.04). Multivariate analysis revealed rapidly or ultimately fatal disease, septic shock and polymicrobial bacteremia as independent prognostic factors. Conclusion: Biliary infection was the leading cause of C. freundii bacteremia. Previous antibiotic therapy, especially with ESCs, frequently predisposed for resistance to these antibiotics. However, resistance to ESCs was not associated with increased mortality. Infection 2003; 31: 202–207 DOI

Oral antibiotic treatment of staphylococcal bone and joint infections in adults

Bone and joint infections, especially implant-associated infections, are difficult to cure. Long-term antibiotic therapy, combined with appropriate surgery and the removal of prostheses, is required. The most common causative organisms in bone and joint infections are staphylococci. Oral agents are often used after an initial course of parenteral antibiotic treatment. However, it is unclear which oral regimens are most effective in staphylococcal bone and joint infections. We review various oral antibiotic regimens and discuss which regimens are effective for this indication.

Factors associated with ciprofloxacin- and cefotaxime-resistant Escherichia coli in women with acute pyelonephritis in the emergency department

BACKGROUND High rates of antimicrobial resistance in Escherichia coli isolated from patients with urinary tract infections have been reported worldwide. The aim of this study was to identify risk factors for resistance to ciprofloxacin (CIP) and cefotaxime (CTX) in E. coli isolated from patients with acute pyelonephritis (APN). METHODS We prospectively identified women over 18 y of age who visited the emergency department of one of 10 hospitals with APN and whose urine culture grew E. coli. The study was conducted from April 16 to June 10, 2012. RESULTS Of the 229 patients identified, 173 (75.5%) had community-associated (CA) infections and 56 (24.5%) had healthcare-associated (HCA) infections. Sixty-seven isolates (29.3%) were resistant to CIP, 45 (19.7%) to CTX, and 29 (12.7%) to both CIP and CTX. Multivariate analyses revealed that hematologic disease, chronic kidney disease, a bed-ridden state, indwelling urinary catheter, antibiotic treatment in the preceding 3 months, and isolation of CIP-resistant E. coli in the urine within the preceding 3 months, were significantly associated with resistance to both CIP and CTX. CONCLUSIONS Chronic conditions and healthcare-associated factors were related to resistance to both fluoroquinolones and third-generation cephalosporins in women with APN. Continued and vigilant surveillance is necessary to monitor the dissemination of antimicrobial resistance in uropathogens.

Impact of a national hospital evaluation program using clinical performance indicators on the use of surgical antibiotic prophylaxis in Korea

OBJECTIVES Clinical performance measurement in surgical antibiotic prophylaxis (SAP) was implemented as part of a national hospital evaluation program (NHEP) in Korea in 2007. This study investigated changes in SAP quality before and after the implementation of clinical performance measurement. METHODS The medical records of patients who underwent three types of surgery that were included for assessment in the NHEP (NHEP surgery) - arthroplasty, gastrectomy, and hysterectomy - and two other types of non-NHEP assessment surgery - craniotomy and spine surgery (non-NHEP surgery) - at six hospitals, from August to October in 2006-2008, were retrospectively reviewed. Three clinical indicators of SAP (antibiotic selection, timing of administration of the first dose, and duration) and the development of surgical site infections (SSIs) were compared before and after implementation. RESULTS A total of 1949 patients were enrolled: 356 arthroplasty, 273 gastrectomy, 615 hysterectomy, 168 craniotomy, and 537 spinal surgery. There were no significant changes in age, gender, wound class, or ASA score for each surgery during the study period. From 2007, SAP quality was significantly improved in NHEP surgery for the three clinical indicators. The timing of administration of the first dose was most markedly improved. SAP quality was also improved in non-NHEP surgery, but not as much as in NHEP surgery. Changes in the SSI rates for each surgery were not significant. CONCLUSIONS Hospital evaluation using clinical performance indicators can considerably improve the use of SAP. Further studies are warranted to investigate whether this hospital evaluation will decrease the development of SSIs.

Severity predictors in eschar-positive scrub typhus and role of serum osteopontin.

We prospectively evaluated severity predictors in terms of host, microorganism, and treatment factors in 153 eschar-positive scrub typhus patients. Severity was assessed with the Acute Physiology and Chronic Health Evaluation (APACHE) II score (< 10 versus ≥ 10) and predefined criteria of severe complications. Genotypes of Orientia tsutsugamushi were determined. Independent risk factors for severity (APACHE II score ≥ 10) were old age, diabetes mellitus, serum osteopontin > 100 ng/mL, and a group of underlying diseases (congestive heart failure, cerebrovascular disease, chronic liver disease, bronchial asthma, and chronic obstructive lung diseases). Anemia (≤ 10 g/dL) and C-reactive protein > 10 mg/dL were indicators of current severity. Neither the delay in antibiotics administration nor strain types (Boryong, Taguchi, or Kanda/Kawasaki) contributed to the severity. The risk factors for severe complications were similar. Serum osteopontin > 100 ng/mL had a negative predictive value of 96% for severe complications. This marker can be used to rule out severe disease status.