Bacteremia from transurethral prostatic resection under prophylactic use of antibiotics

We studied the incidence of the postoperative bacteremia developing in 44 patients undergoing transurethral resection of the prostate under prophylactic use of antibiotics. In 15 of the patients, postoperative endotoxinemia was also investigated. Postoperative bacteremia was found in 10 (22.7%) of the patients, in only one of whom septicemia developed. The incidence of bacteremia was not influenced by the kind of antimicrobial agent administered prophylactically, but was significantly higher in the patients with preoperative urinary tract infection or prostatitis on histological examination of resected prostatic tissue (p less than 0.01). Concerning species isolated from the blood, gram-positive cocci were isolated more frequently than gram-negative bacteria, and Staphylococcus epidermidis was the most common species. In 7 (70%) of the bacteremia patients an identical species was isolated from preoperative urine cultures. In the patients with bacteremia, significant increases in white blood cell count and maximal body temperature were found within 3 hours after the procedure as compared to before the procedure. To lower the postoperative bacteremic rate, appropriate and adequate antimicrobial agents must be used preoperatively in patients with infection of the genitourinary tract. As to blood endotoxin, the endotoxin levels in the patients with postoperative fever did not significantly differ from those of the patients without this complication.     

Bacteremia after renal transplantation.

Of 291 patients who received renal allotransplants in 1964-74, 94 patients developed 121 bacteremic episodes within the first 6 months after transplantation. The death rate was 38%. The bacteremic episodes occurred mainly during the first 2-3 months after transplantation. In 65% of the episodes bacteremia was secondary to urinary tract infections. The bacteria fourn were most often gram-negative rods such as Escherichia coli, Klebsiella and Proteus. Predisposing factors were ureteral complications such as leakage or necrosis of the ureter, leucopenia, immunosuppression, and source of the kidney. The frequency of bacteremia was the same in patients with infectious and non-infectious primary renal disease.     

Clinical correlates of bacteremia in a Veterans Administration extended care facility

Little is known about bacteremia in long-term care facilities. We have conducted a retrospective study during a 12-month period analyzing the clinical correlates of bacteremia in 533 chronically institutionalized, predominantly male patients, with an average age of 69 years. Thirty-four men had forty-two bacteremic illnesses during this period. The incidence rate was 0.30 episodes per 1000 patient care days, and the mortality rate was 21%. The urinary tract was the most frequently identified tissue source (56%), followed by respiratory tract (7%) and skin (7%). Providencia stuartii was the most common gram-negative organism, while Staphylococcus aureus, Streptococcus pneumoniae and enterococcus were the frequent gram-positive microbes. Gram-negative bacteremia accounted for 63% of the episodes (15% mortality rate), and gram-positive bacteremia accounted for 27% (18% mortality rate); 10% of the bacteremias were polymicrobial (25% mortality rate). Most of the isolated organisms were sensitive to available antimicrobial agents. The leading risk factor for bacteremia was an indwelling urinary catheter (odds ratio 39, 95% confidence limits 16 to 97). Patients with urinary catheters at the beginning of the study constituted only 5% of the population, but accounted for 40% of the gram-negative bacteremias during the year of observation.     

Polymicrobial bacteremia: clinical and microbiologic patterns

Between 1971 and 1987, 97 patients with polymicrobial bacteremia (PMB) were seen by a consulting infectious disease service. Seventy-four had severe underlying illnesses, and infection was hospital acquired in 80. PMB resulted from intraabdominal, urinary tract, or soft tissue infection in 45 patients, but a wide range of sources were implicated in the rest. Eleven patients had more than one source for the bacteremia, and, despite intensive diagnostic efforts, 24 had no identifiable source for at least one blood isolate. Bacteremia due to gram-negative bacilli most commonly occurred in intraabdominal, urinary tract, and wound infections; Escherichia coli and Klebsiella species were most frequently isolated. Streptococcus faecalis and Staphylococcus aureus were the predominant gram-positive isolates. Certain bacterial combinations seemed to provide a clue for predicting the source of PMB: for example, S. aureus together with gram-negative facultative rods usually arose from a skin or soft tissue source, whereas S. faecalis together with a gram-negative bacillus could often be traced to an intraabdominal infection. No unique clinical features appeared to predict the occurrence of bacteremia due to multiple rather than to a single organism. The mortality in patients was 21%, lower than has previously been described in PMB but similar to that reported for bacteremia due to a single organism.     

Low mortality among patients with spinal cord injury and bacteremia

We reviewed 103 episodes of bacteremia in 93 patients with spinal cord injury who had bacteremia during initial hospitalization (39 patients) or readmission (54 patients) during 1978-1988. Eighteen episodes (18%) were due to polymicrobial infections. Urinary tract infections (47%), infected pressure areas (19%), and pneumonia (9%) were the most frequent primary infections and sources of the bacteremia. The bacteria most frequently associated with urinary tract infections were enterococci (26%), Escherichia coli (26%), Pseudomonas species (20%), and Klebsiella pneumoniae (12%). Bacteria most frequently isolated from patients with infected pressure areas were anaerobes and Staphylococcus aureus. Bacteremia was the cause of death for 8 patients (9%). The urinary tract was identified only once as the source of gram-negative bacteremia in an immunocompetent patient who died. The reason for the low mortality in patients with spinal cord injury is unclear.     

Bacteremia caused by digestive system endoscopy.

AIM: to evaluate bacteremias caused during endoscopic examination of the digestive tract. PATIENTS AND METHODS: prospective study of randomly selected patients who underwent digestive system endoscopic examination. Emergency endoscopic examinations were excluded. RESULTS: a total of 102 patients were analyzed. Of 44 patients who underwent gastroscopy, 11 (25%) subsequently had positive blood culture, and Staphylococcus spp and Streptococcus spp were isolated. Of 30 patients who underwent colonoscopy, 3 (10%) had positive blood cultures, and Staphylococcus spp were isolated. Of 28 patients who underwent endoscopic retrograde cholangiopancreatography, 11 (39.2%) had positive blood cultures, and Escherichia coli, Morganella morganii, Staphylococcus spp and Streptococcus spp were isolated. No deaths, endocarditis or other septic phenomena were attributed to bacteremia. CONCLUSIONS: the incidence of bacteremia ranged from 10% to 39% depending on the type of endoscopy. The microorganisms that were isolated most frequently were Staphylococcus spp and Streptococcus spp. Gram-negative bacilli and enterobacteria were isolated in patients who had undergone endoscopic retrograde cholangiopancreatography.     

A three-year study of positive blood cultures, with emphasis on prognosis

A study of 37,156 blood cultures over a 3-year period yielded 1,972 positive blood culture episodes, of which 63% were of clinical significance, 26% represented contamination, 7% represented transient bacteremia, and 3% were of indeterminate significance. Mortality curves were calculated for clinically significant bacteremia according to etiologic organism and source. Several curves with different shapes were demonstrated. Quantitative differences were noted between cases of bacteremia arising from different sources and caused by different organisms. No mortality was associated with bacteremia of bone and joint origin. Mortality from bacteremic pneumococcal pneumonia, bacteremia with Escherichia coli of urinary tract origin, endocarditis, and beta-hemolytic streptococcal bacteremia showed an early plateau effect, with a drop before day 20. Cases of bacteremia from intravascular sources other than endocarditis were associated with no initial mortality, but mortality rose progressively after day 5. Bacteremia related to most organisms and sources was associated with mortality that continued until at least day 20.     

Recurrent gram-negative bacteremia

PURPOSE: Recurrent gram-negative bacteremia is defined as two or more episodes of bacteremia occurring in the same patient with an infection-free interval between each episode. Our purpose was to identify patients with recurrent gram-negative bacteremia in order to define possible risk factors for its recurrence. PATIENTS and METHODS: During a recently completed prospective study of all episodes of gram-negative bacteremia at the Buffalo Veterans Administration Center between April 1, 1984, and May 31, 1987, 35 patients with 74 episodes of gram-negative bacteremia were identified. The following information was obtained from all 35 patients: age, service, date of hospital admission, date of the bacteremia, underlying diseases, initial antimicrobial therapy, focus of infection, the presence or absence of shock, antimicrobial susceptibility of the blood isolate, and outcome. RESULTS: All 35 patients were men, had a mean age of 69 years, and all had one or more underlying diseases; 45 percent had a malignancy. The duration of time between a pair of episodes was four weeks or more for 74 percent of 38 pairs of episodes. In 25 of 38 (66 percent) pairs of episodes, the focus of infection was the same; in 80 percent of these 25 pairs, the urinary tract was the focus. Overall, the urinary tract was the focus of gram-negative bacteremia in almost 50 percent. Escherichia coli was the single most common organism isolated (28 percent of all episodes), followed by Proteus mirabilis (17.5 percent) and Pseudomonas aeruginosa (17.5 percent). Six of 35 (17 percent) patients died due to gram-negative bacteremia; five of these six had a respiratory tract focus of infection. CONCLUSIONS: In a population of veterans, recurrent gram-negative bacteremia was identified in almost 10 percent of all patients with gram-negative bacteremia during a 37-month study period. Recurrent gram-negative bacteremia most frequently occurred in the setting of underlying malignancy with the urinary tract as a common focus of infection. The mortality rate of 17 percent was similar to that of all patients with gram-negative bacteremia reported in previous studies.     

Polyclonal bacteremia due to gram-negative rods.

The frequency of, risk factors for, and outcome of polyclonal gram-negative bacteremia are still unknown. We investigated them in a prospective cohort study of patients for whom a blood culture yielded >/=1 species of gram-negative aerobic rod. For each patient, pulsed field gel electrophoresis (PFGE) was performed on 4 colonies of each morphologic type. Episodes of bacteremia were considered polyclonal if caused by >1 PFGE type of the same species. Ten (6.5%) of 153 investigated patients had polyclonal bacteremia. Bacteremia due to nonfermenting rods was the single significant risk factor for polyclonal bacteremia. Complications were equally frequent in all patient groups. However, patients with polyclonal bacteremia received more extensive antibiotic therapy than did patients with monoclonal bacteremia. Nearly 20% of episodes of bacteremia due to nonfermenting rods were polyclonal, but it remains unclear why nonfermenting rods were more likely to cause polyclonal bacteremia than were other gram-negative rods.     

Risk factors for 28-day mortality in elderly patients with extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae bacteremia

Gram-negative bacteremia is common in elderly patients and, compared with younger patients, mortality rates in bacteremic elderly patients are high. ESBL-producing organisms were one of the most important risk factors associated with mortality. In addition, older age is one of risk factors for colonization or infection with ESBL-producing organisms. We conducted a retrospective cohort study to evaluate risk factors of all-cause 28-day mortality in elderly patients with ESBL-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) bacteremia. Patients aged 65 years or older, who had one or more blood cultures positive for E. coli and K. pneumoniae and who were hospitalized between January 2006 and December 2010 at a tertiary-care teaching hospital, were included. 191 bacteremic elderly patients were eligible for the study. The all-cause 28-day mortality rate was 24.6% (47/191). In multivariate analysis, prior antimicrobial therapy (p = 0.014) and an elevated SOFA score (p < 0.001) were independent risk factors for increased mortality, while urinary tract infection (UTI) was an independent determinant for non-mortality (p = 0.011). In the current study, prior antimicrobial therapy within 30 days, an elevated SOFA score and nonurinary source of infection were significantly associated with adverse outcomes in elderly patients with ESBL-producing gram-negative bacteremia.     

Quantitative culture of intravenous catheters and other intravascular inserts

Quantitative cultures were done on 149 intravenous catheters and 40 additional intravascular inserts. Intradermal and intravascular segments of the insert were cultured separately. The inserts were immersed in broth and flushed. The number of colony-forming units (cfu) per insert was estimated by surface culture of serial dilution of the broth. Nonquantitative culture of undiluted broth was also done. Since all inserts associated with bacteremia had at least 10(3) cfu, inserts greater than 10(3) cfu were considered infected. Staphylococcus epidermidis was more likely than more virulent organisms to colonize an insert without causing bacteremia. The inserts in one bacteremic patient were infected from a distant bloodstream focus; however, in the majority of patients, quantitative intradermal cultures suggested that the insertion site was the portal of entry. In bacteremic patients, either a positive quantitative or a nonquantitative culture identified an infected insert. However, only 33% of positive nonquantitative insert cultures from nonbacteremic patients were confirmed by quantitative insert culture.     

Bacteremia in granulocytopenic patients in a tertiary-care general hospital

Episodes of bacteremia in granulocytopenic patients during 1985 and 1986 at a tertiary-care general hospital were reviewed to assess the adequacy of current empiric antimicrobial therapy. The major pathogens in these cases were Pseudomonas aeruginosa, Enterobacteriaceae organisms, and Staphylococcus epidermidis. This combination of pathogens differed from that found at the same facility from 1975 to 1977, when Staphylococcus aureus and streptococci predominated. When apparent, the sources of infection were predominantly venous catheters, the lower respiratory tract, and the urinary tract; most frequently there was no identifiable focus. S. epidermidis and streptococci were isolated more frequently during initial episodes of febrile bacteremia, and P. aeruginosa was isolated more often during subsequent episodes. If a narrow definition for therapeutic outcome is used, only 38% of episodes had a favorable response; response rates were no different with appropriate or inappropriate therapy. The low response rate may have been related to the use of data from the previous review to guide empiric therapy and to the subsequent inadequate treatment of infections caused by Pseudomonas and Enterobacter organisms. The overall mortality per total bacteremic episodes was 19%, and the primary factor associated with mortality was pneumonia (P less than .0001). This study emphasizes the need for ongoing surveillance of local patterns of bacteremia to direct empiric therapy.     

Diagnostic challenges and opportunities in older adults with infectious diseases

Infections remain a major threat to the well-being of our growing aged population. The correct and timely diagnosis of infections in older adults is increasingly important in the current age of antimicrobial resistance. Urinary tract infection, pneumonia, and bacteremia present particular challenges. In older patients with bacteremia, blood cultures have comparable yield as compared with younger patients. However, the routine triggers for ordering blood cultures may not be appropriate in older adults. In addition, resistance patterns of isolated pathogens may change with age. The main difficulties in diagnosing urinary tract infections in older adults are caused by an increased prevalence of asymptomatic bacteriuria and frequent use of urinary catheters. However, a combined noninvasive approach that includes history, physical examination, urinary dipstick testing, urine cultures, and simple blood tests can provide direction. In addition, specific guidelines for specific populations are available. In older patients suspected of bacterial pneumonia, bedside pulse oximetry and urinary antigen testing for Streptococcus pneumoniae and Legionella pneumophila provide direction for the clinician. Although infected older adults pose specific and unique diagnostic challenges, a thorough history and physical examination combined with minimally invasive testing will lead to the correct diagnosis in most older adults with infectious diseases, limiting the need for empiric antibiotics in this age group.     

Group B streptococcal bacteremia in men

Twenty-three episodes of bacteremia due to group B Streptococcus (GBS) in men were reviewed for both clinical and microbiologic features. The commonest sources of bacteremia were infections of the respiratory tract (seven cases), skin (five cases), urinary tract (four cases), and intravenous access sites (four cases). Sixteen (70%) of the cases of bacteremia were hospital acquired, and 10 (43%) were polymicrobial (seven with Staphylococcus aureus). GBS bacteremia was generally low-grade and brief as assessed by the percentage and persistence of positive blood cultures. Among patients bacteremic with GBS alone, there were no instances of shock or metastatic suppuration and only one death as a direct result of sepsis. Overall however, nine other patients died of their underlying disease during the same hospitalization. GBS bacteremia in men is, in itself, generally a moderate infection, but it is often found as part of more complex sepsis in hospitalized patients with serious, often fatal, predisposing illnesses.     

Bacteremic disease due to Haemophilus influenzae capsular type f in adults: report of five cases and review

Five cases of bacteremic infections due to Haemophilus influenzae type f in adults are described, and previous reports of type f disease in nonpediatric patients are reviewed. Respiratory tract infections were most common in our series (two cases of pneumonia, one of epiglottitis, and one of nosocomial septicemia probably resulting from aspiration pneumonitis). All of these patients had factors predisposing them to respiratory tract infections, e.g., neurologic disease, congestive heart failure, or cigarette smoking. A fifth patient, who was bacteremic without an apparent primary focus, had dysgammaglobulinemia. Six episodes of bacteremia occurred in five patients; 11 of 13 cultures of blood obtained before parenteral antibiotic therapy were positive. All isolates were biotype I and susceptible to ampicillin. Antibiotic therapy was curative in cases of proved respiratory tract infection but failed in the setting of nosocomial septicemia, perhaps because of delayed initiation. The brevity of antibiotic treatment of the cryptogenic bacteremia permitted infection of a prosthetic vascular graft and recurrent bacteremia. Graft removal and repeated antibiotic therapy were curative.     

Bacteremia in patients with cirrhosis of the liver.

Infections are frequent in patients with liver cirrhosis, as their defenses against infectious agents are altered. But bacteremia occurring in cirrhotic patients has seldom been reported in the literature. From 1981 to 1986, we collected 197 cases with 228 episodes of bacteremia for this retrospective study. The incidence of bacteremia in cirrhotic patients was 8.8%; no significant difference was noted between cirrhotic patients with variant etiologies of HBV(+), HBV(-) and alcohol. But the incidence increased with the severity of the disease (1%, 4.8%, 17.1% in Child's A, B, C groups, respectively). Gram-negative bacteria were the predominant microorganisms of bacteremia (75.6%). Among them, Escherichia coli, Klebsiella pneumoniae and Aeromonas hydrophilia were the three most commonly detected microorganisms. Gram-positive bacterias were detected in 21.2% of patients with bacteremia, with predominance of the Streptococcus group and Staphylococcus aureus. In about 26.3% of cases the infectious sources were the same by bacteria cultures as from blood. The most common sources were spontaneous bacterial peritonitis, urinary tract infection, pneumonia and biliary tree infection. In cirrhotic patients with and without bacteremia, the mortality rate increased significantly in the bacteremia group (54.8% vs 23.2%, P less than 0.05). By Child's classification, the mortality of patients with classes B and C increased significantly after onset of bacteremia. There was no significant difference in mortality between bacteremic patients in the HBV(+), HBV(-) and alcohol groups. In conclusion, bacteremia is a severe complication of liver cirrhosis and a sign of a poor prognosis.     

Difficulty in predicting bacteremia in elderly emergency patients.

STUDY OBJECTIVES: To characterize the clinical presentation and identify factors predictive of bacteremia in elderly patients. DESIGN: Retrospective review of emergency department charts, hospital records, and microbiology reports. SETTING: Community teaching hospital with annual ED census of 65,000 adults. PARTICIPANTS: Seven hundred fifty elderly patients (aged 65 to 99 years) who were evaluated by the emergency physician, had blood cultures obtained in the ED, and were hospitalized with a suspected infectious process during a 12-month period. MEASUREMENTS: Records were analyzed for demographic information, underlying diseases, clinical presentation, laboratory findings, sources of infection, and causative organisms. Using contingency tables, 79 patients with positive blood cultures were compared with a random sample of 136 patients with sterile blood cultures to identify clinical variables significantly (P less than .05) associated with bacteremia. Logistic regression analysis was performed with significant factors to develop a model to predict bacteremia. Sensitivity, specificity, and predictive values were calculated for the model. MAIN RESULTS: The prevalence of bacteremia was 10.6%. Escherichia coli was the most commonly isolated pathogen (29% of cases), and the urinary tract was the most common source of infection (44.3% of cases). Logistic regression analysis showed that altered mental status (odds ratio, 2.88; 95% confidence interval [Cl], 1.52 to 5.50), vomiting (odds ratio, 2.63; 95% Cl, 1.16 to 6.15), and WBC band forms of more than 6% (0.06) (odds ratio, 3.50; 95% Cl, 1.58 to 5.27) were independent predictors of bacteremia. The presence of at least one of these three factors had a sensitivity of 0.85 (95% Cl, 0.75 to 0.92) and a specificity of 0.46 (95% Cl, 0.38 to 0.55) for predicting bacteremia in the study group. The positive predictive value was 0.16 (95% Cl, 0.12 to 0.19) and the negative predictive value was 0.96 (95% Cl, 0.94 to 0.98) for the ED patient group that met inclusion criteria. CONCLUSION: Elderly patients fail to manifest identifiable clinical features indicative of bloodstream infection. The sensitivity and specificity of the best statistical model for identifying bacteremic elderly patients suggest that clinical indicators alone are unreliable predictors of bacteremia in the geriatric ED population studied.     

Initial management of serious urinary tract infection

OBJECTIVE: To obtain information necessary for the development of initial antibiotic treatment guidelines for patients with serious urinary tract infections. DESIGN: Retrospective chart review. SETTING: The medical service of a 533-bed university-affiliated community hospital. PATIENTS: 253 unselected patients hospitalized between January 1985 and December 1987 given principal discharge diagnoses of urinary tract infection, pyelonephritis, or gram-negative rod bacteremia originating in the urinary tract. RESULTS: Three clinically distinct groups were identified: women under 50 years old, older women, and men. Escherichia coli was isolated from 93% of young women, 70% of older women, and 46% of men. Pseudomonas aeruginosa was isolated from 39% of men with one or more urinary tract risk factors, including recent or recurrent urinary tract infections and known genitourinary tract abnormality. The overall prevalence of Group D streptococci was only 1%. More than 20% of the patients in each group were bacteremic. In all groups, resistance to ampicillin and first-generation cephalosporins was common. Trimethoprim-sulfamethoxazole was active in 98% of young women and 85% of older women and men without urinary risk factors. CONCLUSIONS: Age and gender identify clinically important subgroups of patients with serious urinary tract infections. Pending culture results, all patients should be considered bacteremic, ampicillin alone should not be prescribed, and antibiotics effective against P. aeruginosa should be given to men, especially those with risk factors.     

Bacteremia in patients with cirrhosis of the liver

ABSTRACT— Infections are frequent in patients with liver cirrhosis, as their defenses against infectious agents are altered. But bacteremia occurring in cirrhotic patients has seldom been reported in the literature. From 1981 to 1986, we collected 197 cases with 228 episodes of bacteremia for this retrospective study. The incidence of bacteremia in cirrhotic patients was 8.8%; no significant difference was noted between cirrhotic patients with variant etiologies of HBV(+), HBV(–) and alcohol. But the incidence increased with the severity of the disease (1%, 4.8%, 17.1% in Child's A, B, C groups, respectively). Gram-negative bacteria were the predominant microorganisms of bacteremia (75.6%). Among them, Escherichia coli, Klebsiella pneumoniae and Aeromonas hydrophilia were the three most commonly detected microorganisms. Gram-positive bacterias were detected in 21.2% of patients with bacteremia, with predominance of the Streptococcus group and Staphylococcus aureus. In about 26.3% of cases the infectious sources were the same by bacteria cultures as from blood. The most common sources were spontaneous bacterial peritonitis, urinary tract infection, pneumonia and biliary tree infection. In cirrhotic patients with and without bacteremia, the mortality rate increased significantly in the bacteremia group (54.8% vs 23.2%, P<0.05). By Child's classification, the mortality of patients with classes B and C increased significantly after onset of bacteremia. There was no significant difference in mortality between bacteremic patients in the HBV(+), HBV(–) and alcohol groups. In conclusion, bacteremia is a severe complication of liver cirrhosis and a sign of a poor prognosis.     

Wounds caused by corn-harvesting machines: an unusual source of infection due to gram-negative bacilli

The infectious complications in 23 patients with mutilating wounds due to trauma during corn harvesting were compared with those in 41 patients with factory-related hand injuries of similar severity. Initial cultures revealed bacterial growth in 89% of the agricultural wounds and in 63% of the factory wounds. A mean of 3.8 initial bacterial species were isolated per corn-harvesting wound vs. 0.9 species per factory wound. Gram-negative rods were recovered from 81% of the agricultural wounds; the commonest of these organisms were Enterobacter species and Xanthomonas maltophilia. Only 7% of factory-wound cultures grew gram-negative rods. Osteomyelitis, all with gram-negative rods, developed in five (22%) of the patients with farm injuries but did not occur in patients with factory wounds. More gram-negative rods were recovered from environmental cultures of corn-harvesting machines and corn plants than from those of factory machinery.