David Raveh

Surveillance of antimicrobial prophylaxis for surgical procedures.

OBJECTIVE To assess the practice of antimicrobial prophylaxis for surgical procedures in eight surgical departments in a 550-bed teaching hospital. METHODS A list of all major procedures performed in our hospital, with recommendations for prophylaxis based upon the literature, has been distributed since 1993 and is updated periodically. The practice of surgical prophylaxis between January 1 and March 31, 1996, was examined by assessing four variables: (1) Did the particular procedure justify prophylaxis, and was it provided? (2) Was timing optimal, ie, within 1 hour prior to surgery? (3) Was the appropriate antimicrobial selected? (4) Was duration optimal, ie, < or =24 hours? RESULTS During the study period, 2,117 operations were performed, of which 1,631 (77%) were reviewed. Sixty-six percent were clean surgery, 28% clean-contaminated, and 6% contaminated; 72% of procedures were elective, 28% emergencies. Of 1,631 operations requiring prophylaxis, 1,142 (70%) received it, 489 (30%) did not. Of 1,631 patients, 1,392 (85%) received appropriate care: 929 (67%) appropriately received prophylaxis, and 463 (33%) appropriately did not receive prophylaxis. Of 955 patients who received prophylaxis, 26 (3%) did so inappropriately. Of 1,142 patients who should have received prophylaxis, 213 (19%) did not receive it. Female gender, clean surgery, elective operations, and infrequently performed procedures were all significant indicators of inappropriately withheld prophylaxis (P<.001). In addition, the rate of appropriately provided prophylaxis varied between departments from 71% to 97% (P<.001). Assessment of the 929 procedures for which prophylaxis was justified and given revealed that 100% of patients received it on time, the choice of antimicrobial was appropriate in 95% of cases, and duration was < or =24 hours in 91%. CONCLUSIONS Audits of surgical prophylaxis are expected to detect different errors in different institutions. Conducting audits of surgical prophylaxis probably should be part of the routine activity of infection control teams. Feeding the information back to surgeons could improve adherence to recommended guidelines and might contribute to reduced wound infection rates.

A Week by Week Analysis of the Low Risk Criteria for Serious Bacterial Infection in Febrile Neonates

Objective: To examine the reliability of “low-risk” criteria (LRC) to exclude serious bacterial infection (SBI) in febrile neonates (⩽28 days), according to age in weeks. Design: Epidemiological and clinical data and final diagnosis of all febrile neonates presenting to the emergency room from June 1997 to May 2006 were reviewed. Neonates who fulfilled specific LRC for the presence of SBI were classified as LRC+. The prevalence of SBI and the percentage of LRC+ neonates who had SBI were calculated for each of the first 4 weeks of life. Results: A total of 449 neonates were evaluated. Eighty-seven (19.4%) neonates had an SBI. The prevalence of SBI among infants 3–7, 8–14, 15–21 and 22–28 days of age was 21.6%, 26.1%, 17.9% and 12.1%, respectively (p = 0.007 for linear trend after second week of life). Of the 226 LRC+ neonates, 14 (6.2%) had an SBI, including one case of bacteraemia and meningitis and 13 cases of urinary tract infection (UTI). The negative predictive value (NPV) of the LRC for SBI was 93.8% (95% CI 90.1% to 96.4%). The prevalence of SBI among LRC+ infants 3–7, 8–14, 15–21 and 22–28 days of age was similar, with rates of 15%, 6.3%, 3.0% and 6.7%, respectively. Conclusion: LRC are not sufficiently reliable to exclude the presence of SBI, including bacteraemia and meningitis in febrile neonates of all ages. All febrile neonates should therefore be hospitalised, undergo a full “sepsis evaluation” and receive empirical intravenous antibiotic therapy.

Incidence and risk factors for surgical infection after total knee replacement

Surgical site infection (SSI) after total knee replacement (TKR) is a devastating complication. We performed a retrospective study of all consecutive TKRs performed during a 2-y period. Surgical site infection (SSI) was defined by standard criteria. All patients were examined 1 y following surgery. Of 180 patients undergoing TKR, 10 (5.6%) developed a superficial (3, 1.7%) or deep (7, 3.9%) SSI. Two independent risk factors for SSI were detected: left knees became infected more often (9/92, 9.8%) than right knees (1/88, 1.1%) (Relative Risk 6.7±95% CI 1.7–26.8); and 7/72 (9.7%) patients receiving a type-1 prosthesis developed infection versus 3/104 (3.1%) receiving a type-2 prosthesis (RR 4.7, 95% CI 1.18–18.4). Investigation of the operating room revealed 3 problems: there was significant traffic through the door on the left of the patient; a non-standard horizontal-flow air conditioner had been installed above that door; a tool-washing sink was in use on the other side of that door. Infection control guidelines were rehearsed: the sink was removed, the air conditioner was disconnected, and the door was locked. In a prospective survey performed 2 y later only 1/45 patients (2.2%) undergoing TKR developed a superficial SSI (p=0.5). Correction of independent risk factors for infection following TKR led to a decrease in SSI rate.

Prevalence and predictive features of bacteremic urinary tract infection in emergency department patients

The aim of this study was to determine the prevalence and predictive features of bacteremia among patients evaluated in the emergency department for urinary tract infection. Of the 350 patients with symptomatic urinary tract infection included in this retrospective study, 53 (15%; 95%CI 11.6–19.4%) were bacteremic. Five variables were independently associated with bacteremia: residence at home rather than in an institution (OR 4; 95%CI 1.5–10.7), presence of an indwelling urinary catheter (OR 3.3; 95%CI 1.3–8.8), presence of band forms in the blood count (OR 3.3; 95%CI 1.5–7.2), shaking chills (OR 2.3; 95%CI 1.1–4.8), and neutrophilia (OR 1.1; 95%CI 1.04–1.15). These easily assessable parameters may assist in the diagnosis of bacteremic urinary tract infection and the selection of empiric antibiotic treatment, thus potentially improving a patient’s prognosis.

Predictive factors of morbidity in childhood parapneumonic effusion-associated pneumonia: a retrospective study.

Study Objective: To find the clinical and laboratory criteria that best predict a prolonged fever in children with parapneumonic effusion-associated pneumonia treated conservatively. Design: Retrospective, cohort study. Patients: Children admitted to the Shaare Zedek Medical Center between January 1, 1997, and December 31, 2006, and who had been discharged with a diagnosis of empyema and pleurisy. Measurements and Results: One hundred-twenty children were included, all of whom were treated with antibiotics; in 80 patients, a thoracic drain was introduced; in 23, pleural tap was performed; and in 17 patients, no special procedure was performed. In no case was video-assisted thoracic surgery performed. The mean total days of fever was 12.8 ± 5.9 (2–29 days), and the mean length of stay at the hospital was 11.5 ± 4.9 (3–25) days. In 44 patients (37%), a bacterial culture was positive either in blood or in pleural fluid or both. A positive blood or a positive pleural fluid culture was significantly associated with a prolonged fever as was a history of an underlying disease. Platelet counts, serum Na, serum protein, pleural lactate dehydrogenase (LDH), pleural glucose, pleural/serum LDH ratio, pleural/serum glucose ratio, and pleural fluid pH were the only factors significantly but weakly correlated with the total duration of fever or duration of fever after admission. A “fever duration” score using platelet count, pleural fluid pH, pleural/serum LDH ratio, and pleural/serum glucose ratio predicted a prolonged course of fever (>7 days) with a sensitivity of 91% (95% confidence interval: 60%–100%) and a specificity of 47% (95% confidence interval: 25%–71%). Conclusions: In children with parapneumonic effusion-associated pneumonia, a positive bacterial culture and an underlying disease are associated with prolonged fever. A low score based on platelet count, pH pleural fluid and glucose, and LDH pleural/serum ratio is associated with a prolonged fever. We speculate that children with the risk factors mentioned earlier may be the best candidates for an early aggressive approach.

Susceptibility trends in bacteraemias: analyses of 7544 patient-unique bacteraemic episodes spanning 11 years (1990-2000).

The aim of the present study was to design more accurate tools for the selection of appropriate antimicrobial therapy for hospitalized patients with suspected sepsis. We created a large database comprising data on all patient-unique blood cultures obtained over an 11 year period (1 January, 1990 through 31 December, 2000). Improved statistical tools were applied to assess the trends in in vitro activity of individual antibiotic agents against various bacteria over time, and to calculate susceptibility rates of subsets of organisms. During the 11 year study period, 173571 blood cultures were obtained, of which 17703 (10.2%) were positive, with 7544 patient-unique blood cultures (4.3%). The mean annual number of positive, patient-unique cultures was 686 (standard deviation=79). The 10 most frequently isolated organisms were: Escherichia coli (1494), Staphylococcus aureus (1240), Klebsiella pneumoniae (779), Enterococcus spp. (631), Pseudomonas aeruginosa (488), Streptococcus pneumoniae (447), Enterobacter spp. (338), Acinetobacter spp. (298), Proteus mirabilis (260) and Candida spp. (254). No significant change was detected in the annual rates (means, standard deviations) per 1000 admissions of these organisms: the highest was E. coli (5.5, 1), the lowest was Candida (1, 0.3). Forty percent of organisms (N=2943) were obtained from patients in the emergency department (ED), 23% (1744) in medical departments, 15% (1134) in paediatric units, 13% (998) on surgical wards and 9% (709) in intensive care units (ICUs). Trend statistical analysis revealed a significant decrease in susceptibility in ED Enterobacteriaceae to eight of 15 (53%) tested antimicrobials, with a mean annual decrease of 1.6%+/-0.6%, in the ICU isolates, a significant decrease was detected in only five (33%) of the tested antimicrobials, with a mean annual decrease of 2.5%+/-1.3%. The difference in susceptibility between ED and ICU isolates was significant for all antimicrobials (P<0.001). A significant decrease in the susceptibility of E coli to nine of 15 drugs (60%) was detected, ranging from 0.7% to 2.7% annually. In K. pneumoniae a significant decrease in susceptibility of K. pneumoniae was detected with only two agents. Pseudomonas spp. isolates remained highly sensitive to all traditional anti-pseudomonal agents, without significant decay in sensitivity rates over time. Susceptibility of S. aureus to methicillin decreased significantly for several subsets of patients (P<0.001). Marked differences in susceptibility rates between the departments were detected. Trend statistical analyses, when appropriately applied to multi-year databases of microbial susceptibilities, may yield susceptibility tables that are significantly more accurate than traditional semi-annual or annual tables.

Susceptibilities of ESBL-Producing Enterobacteriaceae to Ertapenem, Meropenem and Piperacillin-Tazobactam with and without Clavulanic Acid

Background: Faced with the extended-spectrum β-lactamase (ESBL) pandemic, we compared the susceptibilities of ESBL-producing Enterobacteriaceae to ertapenem, meropenem and piperacillin-tazobactam with and without clavulanate. Methods: 121 strains of Escherichia coli and Klebsiella were studied. 70 strains were originally reported as resistant to ceftazidime based upon disk diffusion; 51 strains were originally reported as sensitive to ceftazidime based upon previous guidelines of the National Committee for Clinical Laboratory Standards, but subsequently shown to be ESBL producers. Minimal inhibitory concentrations (MICs) of the strains towards ertapenem, meropenem and piperacillin-tazobactam were determined by Etest. The effect of adding clavulanate on the MICs was determined by performing the Etest, using plates containing 2 µg/ml of clavulanate. Results: The MIC90 of all isolates was 0.094 and 0.25 µg/ml for ertapenem, 0.032 and 0.064 µg/ml for meropenem, and 16 and 256 µg/ml for piperacillin-tazobactam with and without clavulanate, respectively. Conclusions: ESBL-producing organisms were more susceptible to meropenem than to ertapenem, although the MICs to ertapenem were well within clinically achievable levels. Piperacillin-tazobactam was ineffective in a large percentage of isolates. The presence of clavulanate resulted in a 5-fold decrease in the MIC of ertapenem and in a drastic reduction in the MIC of piperacillin-tazobactam. The decrease observed with ertapenem is unlikely to be of clinical significance. Thus, in our hospital, ertapenem could be a good meropenem-sparing agent for infections due to ESBL-producing organisms. Piperacillin-tazobactam appeared to be a poor choice, as our isolates produce ESBLs which are not successfully inhibited by tazobactam.

Clinical characteristics of patients with psoas abscess due to non-typhi Salmonella

Infections due to Salmonella spp. are common and their incidence appears to be increasing in many countries [1, 2]. Non-typhoidal Salmonella infections are usually associated with contaminated food products [3]. Salmonellosis may present in five forms: asymptomatic chronic carrier state, gastroenteritis, enteric fever, bacteremia and extraintestinal localized complications, of which endovascular infection is one of the most serious [4, 5, 6]. Psoas abscess has been reported only very rarely. Between 1990 and 2000, 7,544 patients were diagnosed in our hospital with bacteremia. Of these patients, 120 (1.6%) had Salmonella bacteremia [7]. Eight of these patients (7%) had Salmonella typhi, and of the 112 patients with non-typhi Salmonella bacteremia, 68 (61%) were children and 44 (39%) were adults. None of the children nor any of the eight adults younger than 50 years old were diagnosed with psoas abscess. However, of the 36 adults older than 50 years who had non-typhi Salmonella bacteremia, two patients (5.5%) had a psoas abscess. It is not unlikely that bacteremia in these patients was secondary to the psoas abscess, which may have formed weeks or months earlier after primary bacteremia or direct extension from an adjacent site. The association of Salmonella bacteremia and localized symptoms led to the conduction of appropriate tests and the eventual diagnosis of psoas abscess. Patient No. 1, a 75-year-old woman with an 18-month history of idiopathic thrombocytopenic purpura (ITP) was seen in March 2000 for relapse of ITP. She had been previously treated with steroids, which were tapered and discontinued 3 months earlier. Treatment with steroids was resumed and intravenous gammaglobulin was added. Several days later she complained of a sudden onset of severe pain in her left hip, accompanied by a low-grade fever (37.5–37.8 C). A bone scan was suggestive of avascular necrosis of the neck of the left femur. A radiogram of the joint was negative. Two blood cultures and a urine culture grew Salmonella enteritidis. She was started on ampicillin 8 g/day in four divided doses. A computerized tomographic (CT) scan of the abdomen revealed multiple abscesses in the left iliopsoas muscle. Oral ciprofloxacin, 750 mg twice daily, was added. A drain was inserted into the left iliac fossa and pus was drained, from which Salmonella enteritidis was isolated. After prolonged percutaneous drainage and antibiotic treatment, cultures of the drained material became negative, and the patient made a complete recovery. Patient No. 2, a 74-year-old woman, was admitted to hospital in May 2000 with a 2-month history of rightsided groin pain radiating to the right hip and upper thigh without trauma, and a temperature of 38.8 C that had started the day before. An orthopedic surgeon had examined her a month previously and had ascribed her symptoms to discopathy. A bone scan, performed 1 month prior to her admission, was reported as demonstrating an increased uptake in the spine and right hip joint, which was ascribed to arthritic changes. Her past medical history included myasthenia gravis for which she had undergone Y. Schlesinger · A. M. Yinnon ()) · D. Raveh Infectious Disease Unit, Shaare Zedek Medical Center, P.O. Box 3235, 91031 Jerusalem, Israel e-mail: Yinnon@SZMC.org.il Tel.: +972-2-6555076 Fax: +972-2-6555076

Direct fluconazole susceptibility testing of positive Candida blood cultures by flow cytometry.

The standard methods for yeast susceptibility testing require 24–48 h of incubation. As there has been an increase in incidence of non‐albicans Candida species, the clinician is very often wary of initiating therapy with fluconazole until a final susceptibility report is generated, especially when treating very sick patients. A rapid reliable susceptibility testing method would enable the clinician to prescribe fluconazole, thus avoiding more toxic or expensive therapy. To determine the feasibility of direct susceptibility testing of Candida species to fluconazole by a rapid flow cytometric method, 50 Candida strains were seeded into blood culture bottles and were tested for susceptibility to fluconazole directly from the bottles after their being flagged as positive by the blood culture instrument. Minimal inhibitory concentration (MIC) determined by fluorescent flow cytometry (FACS) showed excellent agreement to that determined by macrodilution. Following the seeding experiments, 30 true patient specimens were tested directly from positive blood cultures, and MIC determined by both methods showed excellent agreement. Antifungal susceptibility testing by FACS directly from positive blood culture bottles is a reliable, rapid method for susceptibility testing of Candida to fluconazole. The method allows same‐day results, does not require subculture to agar media, and can greatly assist in the selection of appropriate antifungal therapy.

Infective endocarditis due to Moraxella lacunata: report of 4 patients and review of published cases of Moraxella endocarditis.

Moraxella is an aerobic, oxidase-positive, Gram-negative coccobacillus, which is rarely associated with serious and invasive infections. We describe 4 cases of Moraxella lacunata endocarditis and review 12 previously published cases of Moraxella endocarditis, including 1 further case with M. lacunata, 5 with M. catarrhalis, 2 with M. phenylperuvica and the remainder consisting of 1 case each of M. liquefaciens, M. osloensis, M. nonliquefaciens and 1 non-specified. Of these 16 patients, 5 had prosthetic valves, 5 suffered from an underlying heart abnormality, and the other 6 had normal hearts. Therapy consisted of a beta-lactam antimicrobial and, in several instances, an aminoglycoside as well. The mean duration of antibiotic treatment was 35±13 d. Four patients (25%) underwent surgery and 4 out of 16 (25%) died. Moraxella should be added to the growing list of organisms which may occasionally cause infective endocarditis, even in patients without preexisting valvular abnormality.