Adriana M. Rueda

The Association between Pneumococcal Pneumonia and Acute Cardiac Events

BACKGROUND Increased cardiac stress, hypoxemia, and inflammation may contribute to acute cardiac events, such as myocardial infarction (MI), arrhythmia, and/or congestive heart failure (CHF). We sought to determine the incidence of such events in patients who were hospitalized for community-acquired pneumococcal pneumonia. METHODS We studied the medical records of all patients who were admitted for pneumococcal pneumonia during a 5-year period (2001-2005) to identify those who had MI, atrial fibrillation or ventricular tachycardia, or new-onset or worsening CHF at the time of hospital admission. RESULTS Of 170 patients, 33 (19.4%) had > or =1 of these major cardiac events. Twelve had MI, of whom 2 also had arrhythmia and 5 had new-onset or worsening CHF. Eight had new-onset atrial fibrillation or ventricular tachycardia; 6 of these also had new CHF. Thirteen had newly diagnosed or worsening CHF, without MI or new arrhythmias. Hypoxemia and anemia were prominent. Importantly, patients with concurrent pneumococcal pneumonia and cardiac events had a significantly higher mortality than those with pneumococcal pneumonia alone (P<.008). The coexistence of pulmonary and cardiac disease was often overlooked by admitting physicians who, seeking a unifying diagnosis, emphasized one diagnosis to the exclusion of the other. CONCLUSIONS Patients with pneumococcal pneumonia are at substantial risk for a concurrent acute cardiac event, such as MI, serious arrhythmia, or new or worsening CHF. This concurrence significantly increases mortality due to pneumonia. Admitting physicians tend to seek a unifying diagnosis, but the frequent coexistence of pneumonia and cardiac events indicates the importance of considering multiple diagnoses.

Community-associated strains of methicillin-resistant Staphylococccus aureus as the cause of healthcare-associated infection

OBJECTIVE Methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients with community-associated infection have been described as strains genetically distinct from the strains isolated from patients with healthcare-associated infection. This study examines the hypothesis that community-associated MRSA (CA-MRSA) strains now cause serious infections in hospitalized patients. METHODS Thirty-seven clinical MRSA isolates were randomly selected from blood isolates obtained from July 2003 through June 2004. Strains were tested for staphylococcal chromosomal cassette mec (SCCmec) type, pulsed-field gel electrophoresis (PFGE) type, and presence of Panton-Valentine leukocidin (PVL) genes. Medical records review and epidemiologic classification was performed by an investigator blinded to the results of the bacterial strain analysis. Episodes of bloodstream infection were independently classified as either community-associated or healthcare-associated infections, and bacterial isolates were independently classified as either CA-MRSA strains or healthcare-associated MRSA (HA-MRSA) strains, according to established definitions. SETTING A tertiary care Veterans Affairs Medical Center. RESULTS Twenty-four (65%) of 37 MRSA isolates were SCCmec type IV, a genetic type characteristic of CA-MRSA strains; 22 of these 24 isolates belonged to the CA-MRSA clone USA300 and carried PVL genes. Thirteen (35%) of the 37 strains were SCCmec type II, of which 12 were USA100-ST5 and 12 lacked PVL genes. Thirty patients (81%) had healthcare-associated infections; 18 (60%) of these 30 were infected with isolates carrying markers of CA-MRSA strains. Of 7 patients with CA-MRSA infections, 6 were infected with isolates belonging to the USA300 clone. Patients with healthcare-associated bloodstream infections were as likely to be infected with a CA-MRSA strain as patients with a community-associated infection (P = .38). CONCLUSIONS MRSA strains with molecular characteristics of CA-MRSA strains have emerged as an important cause of serious healthcare-associated infection in our hospital.

Acute Bacterial Pneumonia is Associated With the Occurrence of Acute Coronary Syndromes

A link between acute infections and the development of acute coronary syndromes (ACS) has been proposed. We used retrospective cohort and self-controlled case series analyses to define the closeness of the association between acute bacterial pneumonia due to Streptococcus pneumoniae or Haemophilus influenzae and ACS. For the retrospective cohort analysis we included a control group of patients with admission diagnoses other than pneumonia or ACS. For the self-controlled case series analysis, we made within-person comparisons of the risk for ACS during the 15 days after admission for pneumonia with that of 365 days before and after that event. In 206 pneumonia patients (144 S. pneumoniae, 62 H. influenzae) we identified 22 (10.7%) cases of ACS, which compared to 6 (1.5%) among 395 controls resulted in an odds ratio (OR) of 7.8 (95% confidence interval [CI], 3.1-19.4). With multivariate logistic regression analysis, the OR for ACS in the pneumonia group remained elevated (OR, 8.5; 95% CI, 3.4-22.2). By the self-controlled case series method, the risk of ACS remarkably increased during the first 15 days after the diagnosis of pneumonia (incidence rate ratio, 47.6; 95% CI, 24.5-92.5). The characteristics and strength of these associations suggest a causal role for the acute infection in this relationship. Abbreviations: ACS = acute coronary syndromes, CI = confidence interval, ICU = intensive care unit, IRR = incidence rate ratio, OR = odds ratio.

Antibody persistence ten years after first and second doses of 23-valent pneumococcal polysaccharide vaccine, and immunogenicity and safety of second and third doses in older adults.

In a study of older adults, first and second doses of 23-valent pneumococcal polysaccharide vaccine (PN23) induced IgG increases for all 8 vaccine serotypes tested. Participants (N=143, mean age 76 years) were re-enrolled to study antibody levels after ten years, and safety and immunogenicity of another PN23 dose. Ten years after first or second doses, mean IgG concentrations exceeded vaccine-naïve levels for 7 of 8 serotypes tested. Second and third doses administered at this time were generally well tolerated and were immunogenic, inducing similar postvaccination levels. Immunogenicity is preserved after multiple PN23 doses without evidence of a lower than expected immune response (i.e., without hyporesponsiveness).

The obesity paradox in community-acquired bacterial pneumonia

BACKGROUND The impact of obesity on the outcome of pneumonia is uncertain. METHODS We retrospectively identified 266 hospitalized patients with proven pneumococcal or Haemophilus community-acquired pneumonia who had at least one body mass index (BMI, kg/m²) value documented in the 3 months before admission. Patients were classified as underweight (BMI <18.5), normal weight (BMI 18.5 to <25), overweight (BMI 25 to <30), or obese (BMI ≥30). The association of absolute BMI values and BMI categories with the mortality at 30 days after admission for pneumonia was investigated. RESULTS Increasing BMI values were associated with reduced 30-day mortality, even after adjustment for significant covariates (odds ratio 0.88, confidence interval 0.81-0.96; p<0.01). There was a significant trend towards lower mortality in the overweight and obese (non-parametric trend, p=0.02). CONCLUSIONS Our data suggest that obesity may exert a protective effect against 30-day mortality from community-acquired bacterial pneumonia.

The spectrum of invasive pneumococcal disease at an adult tertiary care hospital in the early 21st century.

Despite widespread pneumococcal vaccination of children and adults, invasive pneumococcal disease (IPD) remains prominent. Using our database of all Streptococcus pneumoniae infections at the Veterans Affairs Medical Center, Houston, Texas, since 2000, we reviewed cases of IPD, defined as the isolation of pneumococci from any normally sterile body site. In 136 cases, the mean age of patients was 63 years; 43% were African American, a higher proportion than the 30% served by our hospital. One hundred sixteen patients (85%) had pneumonia, of whom 3 also had empyema. Seven had bacteremia with no apparent source, 5 meningitis, 5 spontaneous bacterial peritonitis, 3 septic arthritis, 2 endocarditis, and individual patients had osteomyelitis and/or localized abscesses. One hundred twenty-one patients (89%) had ≥1 underlying condition associated with susceptibility to pneumococcal infection, and another 8 (6%) were aged >65 years old. Thus only 5% of patients lacked a condition for which 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended. Fifty-five percent had been vaccinated; similar proportions of vaccine serotypes infected previously vaccinated and nonvaccinated patients. All but 2 isolates were fully susceptible to penicillin and cefotaxime as currently defined. Consistent with substantial replacement of infecting serotypes since the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), none of the predominant infecting serotypes was included in PCV7, although all except for 6A were contained in PPV23. The overall mortality at 30 days was 16% and was similar in vaccinated and nonvaccinated subjects. IPD causes a wide spectrum of disease. Mortality is substantial. PPV23 is clearly not fully protective. Abbreviations: CSF = cerebrospinal fluid, IPD = invasive pneumococcal disease, MEDVAMC = Michael E. DeBakey Veterans Affairs Medical Center, MIC = minimum inhibitory concentration, PCR = polymerase chain reaction, PCV7 = 7-valent pneumococcal conjugate vaccine, PPV23 = 23-valent pneumococcal polysaccharide vaccine. Abbreviations: CSF = cerebrospinal fluid, IPD = invasive pneumococcal disease, MEDVAMC = Michael E. DeBakey Veterans Affairs Medical Center, MIC = minimum inhibitory concentration, PCR = polymerase chain reaction, PCV7 = 7-valent pneumococcal conjugate vaccine, PPV23 = 23-valent pneumococcal polysaccharide vaccine.

Long-term survival following pneumococcal pneumonia

We studied the long-term survival of patients who recovered from pneumococcal pneumonia. Mortality was increased for up to 10 years after documented pneumococcal pneumonia and was greater in proportion to the PORT score at admission and among persons who had bacteremic disease.

Hyperglycemia in diabetics and non-diabetics: Effect on the risk for and severity of pneumococcal pneumonia

OBJECTIVES We sought to determine whether poor glucose control among diabetics is associated with increased risk for pneumococcal pneumonia and whether elevated admitting plasma glucose (APG) levels are associated with increased severity of this infection in diabetic and non-diabetic patients. METHODS We compared hemoglobin A(1c) (HbA(1c)) in diabetics who had pneumococcal pneumonia with diabetic case-controls who did not have pneumonia. In patients with pneumococcal pneumonia, we related APG to disease severity as determined by SMART-COP score, need for ICU admission, and mortality at 7 and 30 days. RESULTS Fifty-three of 233 patients with pneumococcal pneumonia (22.7%) were diabetic. Diabetics with pneumonia had poorer glycemic control than diabetic case-controls (HbA(1c) 8.2% vs. 7.2%, respectively, P<0.01). In pneumococcal pneumonia patients, SMART-COP scores, need for ICU admission, and mortality increased in proportion to the APG. These findings were attributable to the significant association between hyperglycemia and severity in non-diabetics. CONCLUSIONS Poor glycemic control predisposes diabetics to pneumococcal pneumonia but, among diabetics, the degree of hyperglycemia at admission is not associated with increased disease severity. In contrast, among non-diabetics with pneumococcal pneumonia, hyperglycemia is a marker for severe disease and increased mortality, perhaps reflecting massive release of cytokines and glucocorticosteroids in overwhelming infection.

Multiple-dose granulocyte-macrophage-colony-stimulating factor plus 23-valent polysaccharide pneumococcal vaccine in patients with chronic lymphocytic leukemia: a prospective, randomized trial of safety and immunogenicity.

For the current study, the authors sought to determine whether administration of multiple‐dose granulocyte‐macrophage–colony‐stimulating factor (GM‐CSF) could improve response to standard 23‐valent polysaccharide pneumococcal vaccine (PPV) in patients with chronic lymphocytic leukemia (CLL).

The Incidence of Necrotizing Changes in Adults With Pneumococcal Pneumonia

BACKGROUND Necrotizing pneumonia is generally considered a rare complication of pneumococcal infection in adults. We systematically studied the incidence of necrotizing changes in adult patients with pneumococcal pneumonia and examined the severity of infection, role of causative serotypes, and association with bacteremia. METHODS We used a database of all pneumococcal infections identified at our medical center between 2000 and 2010. Original readings of chest X-rays (CXR) and computerized tomography (CT) were noted. Images were then independently reevaluated by 2 radiologists. The severity of disease at admission was assessed using SMART-COP and Pneumonia Outcomes Research Team (PORT) scoring systems. RESULTS In 351 cases of pneumococcal pneumonia, necrosis was reported in no (0%) original CXR readings and in 6 of 136 (4.4%) CTs. With rereading, 8 of 351 (2.3%) CXR and 15 of 136 (11.0%) CT had necrotizing changes. Overall, these changes were identified in 23 of 351 (6.6%) patients. The incidence of bacteremia and the admitting SMART-COP and PORT scores were similar in patients with and without necrosis (P = 1.00, P = .32, and P = .54, respectively). Type 3 pneumococcus was more commonly isolated from patients with necrosis than from patients without necrosis (P = .05), but 10 other serotypes were also implicated in 16 cases for which the organism was available for typing. CONCLUSIONS Necrotizing changes in the lungs were seen in 6.6% of a large series of adults with pneumococcal pneumonia but were often overlooked on initial readings. Patients with necrosis were not more likely to have bacteremia or more severe disease. Type 3 pneumococcus was the most commonly identified serotype.