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PubMed1997

Haemophilus species bacteremia in adults. The importance of the human immunodeficiency virus epidemic.

BACKGROUND: Until the late 1970s, invasive infections caused by Haemophilus species were thought to occur mainly in children and only infrequently in adults. OBJECTIVE: To report the largest series to date of Haemophilus species bacteremia (HB) from a single center. DESIGN: Retrospective. SETTING: Large, tertiary care, general teaching hospital. METHODS: We reviewed the charts of adult patients with HB detected from January 1, 1986, to December 31, 1994. Haemophilus strains were serotyped, and the antimicrobial resistance pattern was analyzed. RESULTS: One hundred sixteen patients had HB (0.26 cases per 1000 admissions). Thirty-eight children and 16 adults were excluded. Human immunodeficiency virus (HIV) infection was the most common underlying condition (n = 18 [29%]), followed by malignant neoplasms (n = 12 [19%]) and chronic obstructive pulmonary disease (n = 12 [19%]). Prevalence in HIV-positive patients was 5 cases per 1000 admissions vs 0.2 cases per 1000 admissions in HIV-negative patients. Infection was nosocomial in 16 patients (26%). Focal diseases were pneumonia in 41 patients (66%), cholangitis in 5 patients (8%), endocarditis in 3 patients (5%), meningitis and septic arthritis each in 1 patient (2%), and primary bacteremia in 9 patients (14%). The HIV-positive patients were significantly younger and presented more frequently with pneumonia (P < .05). Overall, 14 patients died (22%). Bacteremia was polymicrobial in 11 patients (18%). Haemophilus influenzae was isolated in 53 patients (85%). Rates of antimicrobial resistance were 11% to chloramphenicol sodium succinate, 48% to ampicillin sodium, 78% to erythromycin stearate, 76% to combined sulfamethoxazole and trimethoprim, 15% to rifampin, and 57% to clarithromycin. CONCLUSIONS: Infection with HIV has become the most common underlying disease in adults with HB in our hospital. Therapeutic approaches must take into account the high rate of antimicrobial resistance.

AIDS-Related Opportunistic Infections↗
PubMed1993

Escherichia coli bacteremia exacerbates cyclosporine-induced renal vasoconstriction.

The clinical observation that cyclosporine (CSA) nephrotoxicity is particularly severe in patients during and following bacterial infections has recently been made. Transplant recipients develop a marked deterioration of graft function following Escherichia coli bacteremia secondary to urinary tract infection. CSA causes intrarenal vasoconstriction which may account for its nephrotoxicity. We therefore undertook a study using the split hydronephrotic kidney model to investigate the direct in vivo effects of CSA and E. coli bacteremia on the renal microcirculation. Hydronephrotic kidneys in Sprague-Dawley rats were suspended in an environmentally controlled tissue bath. Interlobular arterial (ILA) and afferent (AFF) and efferent (EFF) arteriolar diameters were measured by in vivo videomicroscopy and red cell velocity by Doppler velocimetry. Topical administration of CSA to the kidney in the tissue bath caused a 23 +/- 1% constriction of the ILA and a 67 +/- 5% reduction in blood flow. AFF and EFF arterioles were also constricted by 21 +/- 3 and 16 +/- 2%, respectively. The intravenous infusion of live E. coli was also followed by decreases in ILA diameters and flow (38 +/- 4 and 68 +/- 4%) and AFF diameters (22 +/- 5%) while EFF diameters were unchanged. The infusion of E. coli following addition of CSA to the tissue bath resulted in a dramatically increased constriction of ILA (49 +/- 4%) and AFF (31 +/- 2%) vessels and almost abolished ILA flow (90 +/- 2%). We conclude that in this model, E. coli bacteremia exacerbates CSA-induced preglomerular vasoconstriction and suggests a scientific basis for the severe renal dysfunction noted in transplant recipients during bacterial infection.

Animals↗
PubMed1996

Vasomotor response to pentoxifylline mediates improved renal blood flow to bacteremia.

Bacteremia leads to rapid intrarenal vasoconstriction, mediated by endogenous vasoconstrictors such as TXA2 and endothelin. These changes occur before the onset of neutrophil adherence, platelet aggregation, or increases in proinflammatory cytokines. Pentoxifylline (PTX) increases red cell deformability, reduces neutrophil adhesion, abrogates rises in TNFalpha, and lessens the deleterious effects of other cytokines during prolonged sepsis. PTX also improves renal function in models of established sepsis, but the specific mechanisms of this effect are unclear. Because PTX is a relatively selective visceral vasodilator we sought to determine whether PTX improves renal microvascular hypoperfusion during bacteremia and whether the mechanism involves altered vascular reactivity. Rat hydronephrotic kidneys were studied by videomicroscopy. Interlobular (ILA) arteriolar diameter and flow, afferent (AFF) and efferent (EFF) arteriolar diameters, and cardiac output (CO) were measured at 15-min intervals for 120 min. PTX was infused alone or prior to a bolus injection of live Escherichia coli. The responses were compared to controls infused with equivalent volumes of normal saline alone. PTX led to improved renal blood flow and to pre- and postglomerular vasodilatation. This improvement remained significant compared to bacteremic animals throughout the period of observation. We conclude that PTX improves renal blood flow during bacteremia due to pre- and postglomerular vasodilation. These responses may be a consequence of increased intracellular cAMP and release of vasodilator prostanoids.

Animals↗
PubMed1997

Differential intestinal microvascular dysfunction occurs during bacteremia.

Altered vascular responsiveness is the hallmark of septic shock. Recently, these changes have frequently been attributed to increased production of nitric oxide (NO). Continued exposure to high levels of NO may alter both endothelial and vascular smooth muscle cell function. Although ex vivo studies demonstrate hyporeactivity of large conduit arteries during established sepsis, it is unclear if the same phenomena exist during early sepsis. This is especially true in the small resistance arterioles of the viscera. We used in vivo microscopy of the rat small intestine to assess (1) endothelial-dependent relaxation and vasomotion (periodic contraction and relaxation of blood vessels) in response to acetylcholine (ACH; 10(-8) to 10(-5) M), (2) endothelial-independent relaxation to nitroprusside (NTP; 10(-5) M), and (3) vascular smooth muscle response to norepinephrine (NE; 10(-10) to 10(-7) M) in normal and bacteremic rats (Escherichia coli). There were no alterations in endothelial-dependent or -independent relaxation during bacteremia as measured by mean diameters. However, acute E. coli bacteremia severely impaired vasomotion in A1 (inflow) and A3 (premucosal) arterioles. Vasomotion was returned to baseline levels in A1 with low-dose ACH (10(-8) M) but only partially improved in A3 arterioles (P < 0.05). A1 response to NE was impaired, while A3 were minimally altered despite being more sensitive to E. coli-induced vasoconstriction. These data suggest that bacteremia causes a rapid, differential impairment of both endothelial-dependent (A3 vasomotion) and vascular smooth muscle cell (A1 constriction) functions. These microvascular impairments occur much earlier than previously described and may contribute to sepsis-induced mucosal ischemia of the intestines.

Acetylcholine↗
PubMed1998

Effect of MTP on TNF-alpha in perfused rat liver after bacteremia and ischemia/reperfusion.

INTRODUCTION: Muramlytripeptide phosphatidylethanolamine (MTP) stimulates synthesis of cytokines by hepatic Kupffer cells. We have shown in a perfused rat liver model that secondary ischemia/reperfusion (I/R) downregulates tumor necrosis factor alpha (TNF-alpha) expression after Escherichia coli (EC) bacteremia. Here, we tested the hypothesis that pretreatment with MTP restores cytokine response after sequential bacteremia and I/R. METHODS: Thirty-eight livers were studied in eight groups after intraportal injection of 10(9) live EC or normal saline (NS): (1) normoxic EC; (2) EC + I/R (ischemia began 30 min after EC followed by 2 h of reperfusion); (3) normoxic NS controls; and (4) NS + I/R. Four groups of rats received 300 micrograms of MTP i.v. 24 h prior to liver harvesting; (5) MTP + EC; (6) MTP + EC + I/R; (7) MTP + NS; and (8) MTP + NS + I/R. Bioactive and antigenic TNF-alpha, PGE2 and bacterial clearance were assessed. RESULTS: MTP increased bioactive TNF-alpha response to EC (MTP + EC vs EC controls: 685 +/- 255 U/ml vs 250 +/- 180 U/ml, P < 0.02). I/R did not downregulate TNF-alpha in animals treated with MTP (MTP + NS vs MTP + NS +I/R, P = 0.83). Pretreatment with MTP restored TNF-alpha after I/R MTP + EC + I/R vs EC + I/R: 671 +/- 215 U/ml vs 27 +/- 14 U/ml, P < 0.001) to levels similar to those found in the MTP + EC group (MTP + EC + I/R vs MTP + EC: 671 +/- 215 U/ml vs 685 +/- 255 U/ml, P = 0.75). Finally, bacterial clearance was increased in groups which received MTP. CONCLUSION: In vivo administration of MTP increases hepatic TNF-alpha response to intraportal EC bacteremia by a PGE2 independent mechanism. This response is maintained even after subsequent ischemia and reperfusion.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1997

The hemolytic and complement-activating properties of pneumolysin do not contribute individually to virulence in a pneumococcal bacteremia model.

The virulence of pneumococcal capsular type 2 strain D39 and derivatives with mutations in the pneumolysin gene were examined in a mouse bacteremia model. In CBA/N-XID mice D39 is known to exhibit exponential growth in the blood until the death of the mice at 24 to 36 h. In contrast, PLN, a pneumolysin-deficient derivative of D39, reaches a plateau in growth that is maintained for several days. The growth patterns of D39 and PLN observed in CBA/N-XID mice were also observed in C3H/HeJ and C3H/HeOuJ mice, but not in 129/SvJ and C57BL/6J mice. These results demonstrate that the effect of pneumolysin on bacteremia is dependent on the genetic background of the mice. D39 derivatives with point mutations which abolish the cytotoxic or complement-activating properties of pneumolysin did not have major individual effects on virulence in CBA/N- XID and C3H/HeOuJ mice. A derivative with mutations affecting both the cytotoxic and complement- activating properties resulted in a modest, yet statistically significant, increase in survival time of i.v. challenged CBA/N-XID mice. However, the effect was less marked than that seen with PLN. These findings suggest that the virulence effects of pneumolysin in bacteremia must be due in part to properties other than hemolysis and complement fixation.

Animals↗
PubMed1993

Clinical significance of anaerobic bacteremias in a general hospital. A prospective study from 1988 to 1992.

A prospective study was designed to investigate anaerobic bacteremias and evaluate their incidence and significance in a general hospital. One or more blood cultures positive for anaerobic microorganisms were analyzed from each of a total of 61 patients hospitalized between January 1988 and April 1992, in accordance with an established protocol. The clinical repercussions of bacteremia were also analyzed. Two percent of blood cultures were positive for anaerobes, with an incidence of 0.6 cases per 1000 hospitalized patients. The most frequently isolated anaerobes were Bacteroides fragilis and Clostridium perfringens. Intraabdominal disease was the route of entry in 50% of the patients. A death rate of 37.3% was mostly attributed to B. fragilis. Hospitalization in the surgical department, nosocomial acquisition, previous surgery, critical initial clinical status and the presence of complications were significantly associated with increased death rates. No significant differences were found in the clinical course between patients whose antibiotic treatment was judged adequate and those for whom it was considered inadequate. The frequency and incidence of anaerobic bacteremia was low in our hospital. The well-known clinical and epidemiological characteristics of these infections facilitates their prompt diagnosis and empirical treatment with antibiotics of proven effectiveness against anaerobes.

Adolescent↗
PubMed1996

Effects of prophylactic administration of cefaclor on transient bacteremia after dental extraction.

This study was undertaken to investigate the effects of prophylactic administration of cefaclor on bacteremia after dental extraction. Thirty-nine patients were randomly assigned to receive either 1 g cefaclor (19 patients) or placebo (20 patients) 1 h prior to dental extraction. Blood samples for microbiological investigation were collected before, during, and 10 min after surgery, and were processed by lysis filtration under anaerobic conditions. The incidence of bacteremia with viridans streptococci was 79% in the cefaclor group and 50% in the placebo group during extraction. No difference in the incidence or magnitude of bacteremia was observed when the two patient groups were compared.

Adult↗
PubMedDate not supplied

Anaerobic bacteremia: a retrospective four-year analysis in general medicine and cancer patients.

Anaerobic bacteremia was studied in 32 medical patients (mean age 72 years) in a four-year retrospective analysis. Malignancy was the most common underlying disease and probable portal of entry. The gastrointestinal tract was affected most often, followed by the respiratory and urinary tracts. Bacteremia occurred either following invasive (non surgical) procedures or spontaneously. The clinical course ranged from asymptomatic bacteremia, to mild febrile illness, to sepsis and septic shock (two, 12, 16 and two patients, respectively). The case fatality rate was 25%. The causative organisms were Clostridium and Bacteroides species. All organisms isolated were susceptible to chloramphenicol. Early diagnosis and prompt treatment may reduce mortality in cases of anaerobic sepsis.

Adult↗
PubMed1995

Use of ribotyping to investigate tracheal colonisation by Staphylococcus epidermidis as a source of bacteremia in ventilated newborns.

Ribotyping was used to determine whether a relationship exists between endotracheal tube colonisation with Staphylococcus epidermidis and bacteremia with this organism. Over a three-week period, four mechanically ventilated preterm babies presented with five episodes of infection and bacteremia. For each blood specimen obtained for culture a tracheal aspirate sample was collected at the same time by suctioning. After DNA extraction and cleavage by EcoRI, hybridisation was performed with a digoxigenin-labelled 16S-rDNA probe from Escherichia coli. Five different band patterns were recognised on the membrane. In two children the same band pattern was found in Staphylococcus epidermidis isolated from both blood and tracheal aspirate. Ribotyping thus could be used to differentiate a series of infections from an outbreak and showed that a relationship may exist between tracheal colonisation and bacteremia in mechanically ventilated newborns.

Bacteremia↗
PubMedDate not supplied

Gram-negative bacteremia in non-neutropenic patients: a 3-year review.

The causative organisms, clinical manifestations, factors influencing prognosis, and other epidemiological characteristics of 81 episodes of bacteremia due to gram-negative organisms, in non-neutropenic patients, were studied retrospectively during a 3-year period (1992-1994) at the Department of Internal Medicine of the University Hospital of Heraklion, Crete, Greece. The gram-negative bacteremia incidence was 2% and the overall mortality 12%. All 81 patients had fever; Escherichia coli was the most frequent organism isolated (from 47 patients--58%) and was associated with shock (9/47), disseminated intravascular coagulation (DIC) (8/47), anuria (5/47), adult respiratory distress syndrome (ARDS) (3/47), and pneumonia (1/47). Other less frequent gram-negative microorganisms were Klebsiella spp. (ten patients; 12%), Pseudomonas spp. (7; 7%), Salmonella spp. (5; 6%), Enterobacter spp. (5; 6%), Proteus spp. (3; 3.4%), Stenotrophomonas spp. (3; 3.4%), and Acinetobacter spp. (1; 1.2%). ARDS. shock, DIC, anuria, presence of central venous catheter, urinary catheter, unknown origin of infection and inappropriate treatment were significantly associated with a higher death rate. Early initiation of appropriate therapy was the most important intervention that favorably affected the outcome of gram-negative bacteremias in this patient population.

Adult↗
PubMed2004

Group A beta-hemolytic streptococcal bacteremia.

OBJECTIVE: The aim of this study was to review the clinical features, laboratory findings and the risk factors associated with invasive group A streptococcal infections in children admitted to our institution over a 9-year period (January 1, 1990 through December 31, 1999). METHODS: Medical records of children who had a positive blood culture for group A beta-hemolytic streptococci and children who had this organism isolated from any other sterile site were identified and retrospectively reviewed. RESULTS: Forty-one children with invasive GAS were identified, of whom 15 (36%) were diagnosed between 1990 and 1994, while the balance (26 patients, 63%) were diagnosed between 1995 and 1999 (p< 0.05). The mean age was 4.3 +/- 2.5 years (age range: 2 months to 16 years). Thirteen (32%) patients were infants. Sixteen patients had only bacteremia, while 25 patients had in addition to bacteremia the following: cellulitis (n: 13), osteomyelitis (n: 6), pneumonia (n: 3), meningitis (n: 1), pharyngitis (n:3) and Toxic Shock Syndrome (n: 2). Primary varicella infection constituted the most common predisposing factor for invasive GAS infections and occurred in 11 (27%) patients. Leukocytosis (A white blood cell count > 15,000/mm3) occurred in 21 (51 %) patients, while leukopenia (A white blood cell count < 5000/mm3) occurred in 2 patients. Parenteral crystalline penicillin G followed by oral penicillin or amoxicillin were the most common antibiotics administered. The mean hospital length of stay was 8 days (range: 6 -32 days). All, but one patient survived. The one patient who died had malnutrition and died from streptococcal toxic shock syndrome. CONCLUSION: More cases of invasive GAS were diagnosed during the second half of the study period, however, the overall rate of occurrence of bacteremia during the study period was consistent with previous reports. Primary varicella infection was the most common predisposing factor for invasive GAS infections. The low occurrence of toxic shock syndrome and fatalities among children with invasive GAS infections are consistent with other pediatric but not with adult series.

Adolescent↗
PubMedDate not supplied

An analysis of interleukin-8, interleukin-6 and C-reactive protein serum concentrations to predict fever, gram-negative bacteremia and complicated infection in neutropenic cancer patients.

A prospective study was performed to assess the potential value of interleukin (IL)-8, IL-6, and C-reactive protein (CRP) serum levels to predict fever, gram-negative bacteremia and complicated infection in neutropenic patients with cancer. Serum samples were obtained three times a week during 208 neutropenic episodes following cytotoxic chemotherapy. Fever of any cause developed during 104 out of 191 evaluable episodes. Serum levels of neither cytokine nor CRP were predictive of fever within more than 24 h before its onset. Unlike CRP, both IL-6 and IL-8 serum levels were significantly different between microbiologically documented infections and unexplained fevers. The highest values of IL-6 and IL-8 were observed in episodes of gram-negative bacteremia. Using receiver-operating-characteristic curves, the analysis of cytokine levels measured around the onset of fever indicated that IL-8 is potentially useful for predicting gram-negative bacteremia, with a high negative predictive value of > 90% and a moderate positive predictive value of 50% (sensitivity, 70%; specificity, 91%). In patients with persistent fever, predictions of further clinical complications, defined as prolonged fever of more than 7 days' duration, pneumonia, shock and/or death due to infection, were best predicted by IL-6. With an IL-6 cutoff value of 250 pg/ml in samples obtained 8 to 32 h after onset of fever, the positive predictive value was 92%, the negative predictive value 91% (sensitivity, 85%; specificity, 95%). The positive predictive value of IL-6 in samples obtained another 24 h later from patients still febrile remained > 90%, but the negative predictive value dropped to 47%. In any of the analyses, the predictive values of CRP levels were poor and inferior to either cytokine. These findings may have clinical value in identifying subgroups of patients requiring different therapeutic approaches.

Adolescent↗
PubMed2005

Nosocomial bacteremia in very old patients: predictors of mortality.

BACKGROUND AND AIMS: Nosocomial Bacteremia (NB) is associated with high mortality in elderly patients. To determine specific prognostic factors for 7- and 30-day mortality in elderly patients with NB, we analysed the characteristics of 62 NB patients, retrospectively. METHODS: This retrospective study concerns 62 cases of NB diagnosed within a 3-year period in a geriatric department. Bacteremia is described according to CDC definitions. Epidemiological characteristics, co-morbidities, clinical (activities of daily living (ADL) before NB) and biological findings (neutrophil count, lymphocyte count, albuminemia before NB) were collected for each patient. A systemic clinical reaction was defined by the presence of one of the following parameters: chills, hypothermia <36 degrees C or hyperthermia >38.5 degrees C, or shock. Types of micro-organism and source of NB were also collected. All variables were analysed for mortality at day 7 (7-day mortality) and at day 30 (30-day mortality). RESULTS: The 7-day mortality rate was 21% and the 30-day rate was 45%. In multivariate analysis, 7-day mortality was only associated with the absence of systemic clinical reaction [OR 9.7 (3.7-25.7)]. Again, in multivariate analysis, 30-day mortality was associated with an ADL score <2 [OR 8.3 (4.3-16.4)] and cocci gram positive NB [OR= 3.6 (1.9-6.9)]. CONCLUSIONS: The absence of any systemic clinical reaction as a single independent predictor for 7-day mortality suggests either a poorer immune response to nosocomial bacteremia or a delay in diagnosis. Functional status was the strongest predictor for 30-day mortality. In this population, further prospective studies need to include these factors to evaluate predictors of mortality for serious infectious diseases.

Aged↗
PubMed1998

Lung overinflation without positive end-expiratory pressure promotes bacteremia after experimental Klebsiella pneumoniae inoculation.

OBJECTIVE: To determine the effect of peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) on the development of bacteremia with Klebsiella pneumoniae after mechanical ventilation of intratracheally inoculated rats. DESIGN: Prospective, randomized, animal study. SETTING: Experimental intensive care unit of a University. SUBJECTS: Eighty male Sprague Dawley rats. INTERVENTIONS: Intratracheal inoculation with 100 microliters of saline containing 3.5-5.0 x 10(5) colony forming units (CFUs) K. pneumoniae/ml. Pressure-controlled ventilation (frequency 30 bpm; I/E ratio = 1:2; FIO2 = 1.0) for 180 min at the following settings (PIP/PEEP in cmH2O): 13/3 (n = 16); 13/0 (n = 16); 30/10 (n = 16) and 30/0 (n = 16), starting 22 h after inoculation. Arterial blood samples were obtained and cultured before and 180 min after mechanical ventilation and immediately before sacrifice in two groups of non-ventilated control animals (n = 8 per group). After sacrifice, the lungs were homogenized to determine the number of CFUs K. pneumoniae. MEASUREMENTS AND RESULTS: The number of CFUs recovered from the lungs was comparable in all experimental groups. After 180 min, 11 animals had positive blood cultures for K. pneumoniae in group 30/0, whereas only 2, 0 and 2 animals were positive in 13/3, 13/0 and 30/10, respectively (p < 0.05 group 30/0 versus all other groups). CONCLUSIONS: These data show that 3 h of mechanical ventilation with a PIP of 30 cmH2O without PEEP in rats promotes bacteremia with K. pneumoniae. The use of 10 cmH2O PEEP at such PIP reduces ventilation-induced K. pneumoniae bacteremia.

Animals↗
PubMed2006

Comparison of community-acquired methicillin-resistant Staphylococcus aureus bacteremia to other staphylococcal species in a neonatal intensive care unit.

Hospital acquired infections including staphylococcal species are common in neonatal intensive care units. Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) was recently observed in our unit. The clinical and laboratory characteristics of all neonates with Staphylococcus aureus bacteremia during an 11-year period were retrospectively reviewed. Three groups of patients were compared: 1. Patients with CA-MRSA defined as MRSA-resistant only to beta-lactams, but sensitive to all other antibiotic groups and carried SCCmec IV. 2. Patients with multi-drug-resistant (MDR)-MRSA and 3. Patients with MSSA (methicillin-sensitive S. aureus). Forty-three neonates with documented S. aureus bacteremia were included. Of these 41 were preterm babies. Eleven infants had CA-MRSA, 20 had MDR-MRSA and 12 had MSSA bacteremia, the Panton-Valentine-Leukocidine gene (pvl-gene) was not present in any of these strains. Risk factors, clinical manifestations and laboratory tests were similar in all three groups studied. Although neonates infected with CA-MRSA were more premature and had more related diseases, the mortality rate was similar in all groups (9.1% in the CA-MRSA group). Skin infections, osteomyelitis or pneumatocele were not observed more frequently in the CA-MRSA group. We did not find significant differences in risk factors or outcomes in neonates in the three groups. One possible explanation for this observation is that the CA-MRSA outbreak strain did not contain the pvl-gene, which has been suggested to be a significant virulence factor.

Anti-Bacterial Agents↗
PubMed2002

Risk factors for penicillin resistance and mortality in Korean adults with Streptococcus pneumoniae bacteremia.

A retrospective analysis was performed to measure the incidence of pneumococcal bacteremia and to identify risk factors for penicillin resistance and prognostic factors for outcome in adults. A total of 151 cases of pneumococcal bacteremia were identified from 149 adults during the period 1996-2000. The overall rate of penicillin resistance was 49%, ranging from 54.2% in 1996 to 48.5% in 2000 (P=0.93). Rates of resistance to ceftriaxone, clindamycin, erythromycin, and trimethoprim-sulfamethoxazole were 21.6%, 51%, 62%, and 44.7%, respectively. Multidrug resistance was documented in 47.7% of the cases. Penicillin resistance was significantly associated with solid tumor, biliary drainage catheter, and previous beta-lactam therapy in the univariate analysis. However, the associations were not as significant as independent risk factors in the multivariate analysis. Mortality was 23.8% and did not change significantly during the study period (P=0.06). Mortality rates in cases caused by penicillin-susceptible Streptococcus pneumoniae and penicillin-resistant Streptococcus pneumoniae were 23% and 24.7%, respectively (P=0.81). Mortality was not significantly influenced by penicillin resistance, even high-level resistance (24.4% vs. 20%; P=0.64). Multivariate analysis revealed that antineoplastic chemotherapy, respiratory failure, and acute renal failure were independent prognostic factors for mortality. In conclusion, the rate of penicillin resistance among pneumococcal blood isolates was high in the late 1990s, but penicillin resistance, and even high-level penicillin resistance, was not significantly associated with increased mortality in adults with pneumococcal bacteremia.

Adolescent↗
PubMed2002

Impact of previous use of antibiotics on development of resistance to extended-spectrum cephalosporins in patients with enterobacter bacteremia.

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.

Adult↗