Jan E. Patterson

Mortality from invasive pneumococcal pneumonia in the era of antibiotic resistance, 1995-1997.

OBJECTIVES This study examined epidemiologic factors affecting mortality from pneumococcal pneumonia in 1995 through 1997. METHODS Persons residing in a surveillance area who had community-acquired pneumonia requiring hospitalization and Streptococcus pneumoniae isolated from a sterile site were included in the analysis. Factors affecting mortality were evaluated in univariate and multivariate analyses. The number of deaths from pneumococcal pneumonia requiring hospitalization in the United States in 1996 was estimated. RESULTS Of 5837 cases, 12% were fatal. Increased mortality was associated with older age, underlying disease. Asian race, and residence in Toronto/Peel, Ontario. When these factors were controlled for, increased mortality was not associated with resistance to penicillin or cefotaxime. However, when deaths during the first 4 hospital days were excluded, mortality was significantly associated with penicillin minimum inhibitory concentrations of 4.0 or higher and cefotaxime minimum inhibitory concentrations of 2.0 or higher. In 1996, about 7000 to 12,500 deaths occurred in the United States from pneumococcal pneumonia requiring hospitalization. CONCLUSIONS Older age and underlying disease remain the most important factors influencing death from pneumococcal pneumonia. Mortality was not elevated in most infections with beta-lactam-resistant pneumococci.

Risk Factors for Candidal Bloodstream Infections in Surgical Intensive Care Unit Patients: The NEMIS Prospective Multicenter Study

To assess risk factors for development of candidal blood stream infections (CBSIs), a prospective cohort study was performed at 6 sites that involved all patients admitted to the surgical intensive care unit (SICU) for >48 h over a 2-year period. Among 4276 such patients, 42 CBSIs occurred (9.82 CBSIs per 1000 admissions). The overall incidence was 0.98 CBSIs per 1000 patient days and 1.42 per 1000 SICU days with a central venous catheter in place. In multivariate analysis, factors independently associated with increased risk of CBSI included prior surgery (relative risk [RR], 7.3), acute renal failure (RR, 4.2), receipt of parenteral nutrition (RR, 3.6), and, for patients who had undergone surgery, presence of a triple lumen catheter (RR, 5.4). Receipt of an antifungal agent was associated with decreased risk (RR, 0.3). Prospective clinical studies are needed to identify which antifungal agents are most protective and which high-risk patients will benefit from antifungal prophylaxis.

Risk factors for candidemia in neonatal intensive care unit patients.

Background. Candida species are important nosocomial pathogens in neonatal intensive care unit (NICU) patients. Methods. A prospective cohort study was performed in six geographically diverse NICUs from 1993 to 1995 to determine the incidence of and risk factors for candidemia, including the role of gastrointestinal (GI) tract colonization. Study procedures included rectal swabs to detect fungal colonization and active surveillance to identify risk factors for candidemia. Candida strains obtained from the GI tract and blood were analyzed by pulsed field gel electrophoresis to determine whether colonizing strains caused candidemia. Results. In all, 2847 infants were enrolled and 35 (1.2%) developed candidemia (12.3 cases per 1000 patient discharges or 0.63 case per 1000 catheter days) including 23 of 421 (5.5%) babies ≤1000 g. After adjusting for birth weight and abdominal surgery, forward multivariate logistic regression analysis demonstrated significant risk factors, including gestational age <32 weeks, 5‐min Apgar <5; shock, disseminated intravascular coagulopathy, prior use of intralipid, parenteral nutrition, central venous catheters, H2 blockers, intubation or length of stay >7 days before candidemia (P < 0.05). Catheters, steroids and GI tract colonization were not independent risk factors, but GI tract colonization preceded candidemia in 15 of 35 (43%) case patients. Conclusions. Candida spp. are an important cause of late onset sepsis in NICU patients. The incidence of candidemia might be decreased by the judicious use of treatments identified as risk factors and avoiding H2 blockers.

Methicillin-Resistant Staphylococcus aureus in Two Child Care Centers

Methicillin-resistant Staphylococcus aureus (MRSA) has not been studied in child care centers. The prevalence of MRSA colonization was determined at two centers with an index patient. Two (3%) of 61 children at center X had MRSA; strains from both children and the index illness were pulsed-field gel electrophoresis type B. Nine (24%) of 40 children at center Y had MRSA; strains from 5 children and the index illness were type B, and strains from 4 children were type A. Ten of 11 colonized children were in classes with 2- and 3-year-old children. Colonization with MRSA was not associated with health care contact by subjects or by members of their households. MRSA in child day care centers indicates accelerated spread of MRSA in the community.

BACTERIAL URINARY TRACT INFECTIONS IN DIABETES

Diabetes mellitus has a number of long-term effects on the genitourinary system. These effects predispose to bacterial urinary tract infections in the patient with diabetes mellitus. Bacteriuria is more common in diabetic women than in nondiabetic women because of a combination of host and local risk factors. Upper tract infection complications are also more common in this group. Diabetic patients are at higher risk for intrarenal abscess, with a spectrum of disease ranging from acute focal bacterial pyelonephritis to renal corticomedullary abscess, to the renal carbuncle. A number of uncommon complicated urinary tract infection complications occur more frequently in diabetics, such as emphysematous pyelonephritis and emphysematous pyelitis. Because of the frequency and severity of urinary tract infection in diabetic patients, prompt diagnosis and early therapy is warranted. A plain abdominal radiograph is recommended as a minimum radiographic screening tool in the patient with diabetes presenting with systemic signs of urinary tract infection. Ultrasonography or further radiographic studies such as CT scanning may also be warranted, depending on the clinical picture, to identify upper urinary tract complications early for appropriate intervention.

First Report of the Emergence of CTX-M-Type Extended-Spectrum β-Lactamases (ESBLs) as the Predominant ESBL Isolated in a U.S. Health Care System

ABSTRACT CTX-M-type extended-spectrum β-lactamases (ESBLs) have become increasingly common worldwide, with the notable exception of the United States, where TEM- and SHV-type ESBLs have appeared to predominate. We have noted the emergence of ESBLs in our health care system (the University Health System in San Antonio, TX), especially in Escherichia coli isolates, that preferentially hydrolyze cefotaxime rather than ceftazidime, suggesting the possibility of CTX-M-type enzymes. Microbiology laboratory records were reviewed to identify ESBL-producing isolates and to compare the diameters of ceftazidime disk diffusion zones of inhibition to cefotaxime zone diameters. All isolates had been initially detected and confirmed using the procedures recommended by the Clinical and Laboratory Standards Institute. A total of 94 stored ESBL-producing isolates recovered between January 2000 and June 2006 (predominately from blood and normally sterile fluids) were retrieved for further study and screened using PCR primers specific for the presence of CTX-M, TEM, and SHV ESBLs. Only small numbers of retained ESBL-producing isolates were available for study in 2000 and 2002. The percentages of available ESBL-producing organisms in the following years were found to produce CTX-M enzymes: 2000, 25%; 2001, 10%; 2002, 0%; 2003, 60%; 2004, 69%; 2005, 89%; and 2006, 70%. The most common CTX-M-type ESBL was CTX-M-15, followed by CTX-M-16, CTX-M-8, and CTX-M-14. Comparing the disk diffusion zone diameters of cefotaxime and ceftazidime was helpful with the initial recognition of CTX-M-producing E. coli, which had an average cefotaxime zone diameter 7 mm smaller than the ceftazidime zone. However, comparing ceftazidime and cefotaxime zones for CTX-M-producing Klebsiella spp. was not helpful with initial recognition. CTX-M enzymes were also identified in Proteus mirabilis, Enterobacter spp., and Morganella morganii. Based on pulsed-field gel electrophoresis typing of the E. coli isolates, the CTX-M-producing isolates did not represent the spread of a single clone in the institution or in the community. In conclusion, CTX-M-type ESBLs are now the most common ESBL type isolated from patients in our health care system and may also be present but unrecognized in other U.S. locales.

An analysis of 110 serious enterococcal infections. Epidemiology, antibiotic susceptibility, and outcome.

A prospective, observational study of 110 patients with serious infections due to Enterococcus spp. in 6 university and community teaching hospitals in Connecticut was conducted to define the epidemiology of community and nosocomial serious enterococcal infections and to determine risk factors, including antibiotic resistances, that contribute to outcome. Serious community and nosocomial enterococcal infections involved a variety of sites, and antibiotic resistance was common. Types of infection by major organ system were cardiovascular, 54% (catheter-related bacteremia 28%, primary bacteremia 18%, endocarditis 6%, septic thrombophlebitis 1%); intra-abdominal, 13% (including cholangitis, 6%); renal, 13%; skin and soft tissue, 5%; bone and joint, 4%; pleuropulmonary, 4%; central nervous system, 3%; deep surgical wound, 3%; and endometritis, 2%. Sixty-one percent of infections were nosocomial; 48% of these occurred in the intensive care unit. Enterococcus faecium was responsible for 20% of all infections. Antibiotic resistances among the infections included high-level gentamicin resistance (26%), ampicillin resistance (10%), and vancomycin resistance (8%). Clinical cure was achieved in 64% of patients; 6.8% of patients relapsed, 6.8% had recurrence of the infection with a different pathogen, and overall mortality was 23%. Ampicillin resistance and a high acute physiology and chronic health evaluation (APACHE) II score were highly predictive of lack of cure.

Association of Antibiotic Utilization Measures and Control of Multiple-Drug Resistance in Klebsiella pneumoniae

OBJECTIVE To study the association of antibiotic-utilization measures and control of multidrug-resistant (MDR) Klebsiella pneumoniae after emergence in two hospitals in our medical center. DESIGN AND SETTING Rates of MDR K. pneumoniae at two hospitals were compared before and after acute interventions, including emphasis on Contact Precautions and education in antibiotic utilization. Antipseudomonal beta-lactam antibiotic use was measured before and after the interventions at both hospitals. Pulsed-field gel electrophoresis of whole cell DNA was used as a marker of strain identity. RESULTS Clonal strain dissemination was the major mechanism of emergence at hospital A; emergence was polyclonal at hospital B. Antibiotic-utilization interventions at both institutions included physician education regarding the association of ceftazidime use and MDR K. pneumoniae. At hospital A, ceftazidime use decreased from 4,301 g in the preintervention period, to 1,248 g in the postintervention period. Piperacillin-tazobactam use increased from 12,455 g to 17,464 g. Ceftazidime resistance in K. pneumoniae decreased from 110 (22%) of 503 isolates to 61 (15%) of 407 isolates (P<.05); piperacillin-tazobactam resistance decreased from 181 (36%) of 503 to 77 (19%) of 407 isolates (P<.05). At hospital B, ceftazidime use decreased from 6,533 g in the preintervention period to 4,792 g in the postintervention period. Piperacillin-tazobactam use increased from 58,691 g to 67,027 g. Ceftazidime resistance in K. pneumoniae decreased from 42 (10%) of 415 isolates to 19 (5%) of 383 isolates (P<.05). Piperacillin-tazobactam resistance decreased from 91 (22%) of 415 isolates to 54 (14%) of 383 isolates (P<.05). Follow-up data showed continued decrease in piperacillin-tazobactam resistance despite increased use at both hospitals. CONCLUSIONS Antibiotic-use measures may be particularly important for control of MDR K. pneumoniae, whether emergence is clonal or polyclonal.

Emergence of Daptomycin Resistance in Enterococcus faecium during Daptomycin Therapy

Daptomycin is a cyclic lipopeptide antibiotic that has been available in the United States since September 2003. We report a clinical and bacteriological failure of daptomycin therapy for enterococcal bacteremia. Briefly, a 22-year-old man with Hodgkins lymphoma, subsequent acute myelogenous

National Epidemiology of Mycoses Survey: A Multicenter Study of Strain Variation and Antifungal Susceptibility Among Isolates of Candida Species

The National Epidemiology of Mycoses Survey (NEMIS) involves six academic centers studying fungal infections in surgical and neonatal intensive care unit (ICU) patients. We studied variation in species and strain distribution and anti-fungal susceptibility of 408 isolates of Candida spp. Candida spp. were isolated from blood, other normally sterile site cultures, abscesses, wounds, catheters, and tissue biopsies of 141 patients hospitalized in the surgical (107 patients) and neonatal (34 patients) ICUs of medical centers located in Oregon, Iowa, California, Texas, Georgia, and New York. Isolates were also obtained from selected colonized patients (16 patients) and the hands of health care workers (27 individuals). DNA typing was performed using pulsed field gel electrophoresis, and antifungal susceptibility to amphotericin B, 5-fluorocytosine, fluconazole, and itraconazole was determined using National Committee for Clinical Laboratory Standards (NCCLS) methods. Important variation in susceptibility to itraconazole and fluconazole was noted: MICs of itraconazole ranged from 0.25 microgram/mL (MIC90) in Texas to 2.0 micrograms/mL (MIC90) in New York. Similarly, the MIC90 for fluconazole was higher for isolates from New York (64 micrograms/mL) compared to the other sites (8-16 micrograms/mL). In general, DNA typing revealed patient-unique strains; however, there were 13 instances of possible cross-infection noted in 5 of the medical centers. Notably, 9 of the 13 clusters involved species of Candida other than C. albicans. Potential transmission from patient-to-patient (C. albicans, C. glabrata, C. tropicalis, C. parapsilosis) and health care worker-to-patient (C. albicans, C. parapsilosis, C. krusei) was noted in both surgical ICU and neonatal ICU settings. These data provide further insight into the epidemiology of nosocomial candidiasis in the ICU setting.