An outbreak of infections caused by non-typeable Haemophilus influenzae in an extended care facility.

Nosocomial outbreaks of infection due to non-typeable Haemophilus influenzae (NTHi) are rarely described. There are a few published reports that suggest that elderly patients with underlying pulmonary disease are at risk and that person-to-person spread is key to disease transmission. During the summer months of 2005, we documented an outbreak of NTHi infections in a Veterans Affairs nursing home. Thirteen patients developed conjunctivitis or lower respiratory infection involving a beta-lactamase-negative biotype III NTHi isolate, with an indistinguishable SmaI macrorestriction pattern. Patients were elderly males usually with underlying cardiac and pulmonary disease. A case-control study failed to demonstrate any specific significant risk factor for NTHi infection and there was no evidence of spatial clustering of cases within the nursing home. A random throat culture survey involving nursing home patients during the outbreak showed that only one of 19 persons was colonized with NTHi. The outbreak concluded following appropriate treatment and an emphasis on universal and respiratory droplet precautions. All patients recovered and a specific inciting event for the outbreak was never defined. Literature review revealed a spectrum of responses to nosocomial NTHi infections and a lack of consensus regarding the infection control approach towards NTHi outbreaks.

Serratia marcescens nosocomial infections of the urinary tract associated with urine measuring containers and urinometers.

An outbreak of nosocomial infections of the urinary tract due to a multiply drug-resistant strain of Serratia marcescens occurred at a community hospital. Acquisition of the epidemic strain was associated with the following factors: (1) exposure to the intensive care unit, (2) presence of an indwelling bladder catheter, (3) treatment with antibiotics, and (4) exposure to devices used from measurements of specific gravity and urine volume. An extensive microbiologic evaluation of the hospital environment failed to reveal the epidemic strain of S. marcescens from any site other than urinometers and urine volume measuring containers. Four of four urinometers and three of seven urine measuring containers tested revealed the epidemic organism. Notably, six of these seven positive cultures were obtained in hospital areas in which no patients infected with S. marcescens were located at the time of sampling. The resistant organism was also recovered from one of three pooled handwashings taken from nursing personnel. Thus, the urinometer and urine measuring container may have served as inanimate reservoirs for the resistant S. marcescens which was subsequently inoculated onto the hands of medical personnel or directly to a catheterized patient. Disinfection procedures were identified which eliminated these items as reservoirs. No additional cases of multiply drug-resistant S. marcescens urinary tract infections have been observed since institution of routine disinfection of the inanimate reservoir.

Respiratory infections caused by Branhamella catarrhalis. Selected epidemiologic features.

PURPOSE: This work reviewed existing literature pertaining to the epidemiologic aspects of respiratory tract infections caused by Branhamella catarrhalis, examined certain epidemiologic features of B. catarrhalis infections occurring at this facility, and identified relevant areas in need of further study. PATIENTS AND METHODS: Literature dealing with the epidemiology of B. catarrhalis infections was reviewed. Records in this Veterans Administration hospital microbiology laboratory were reviewed and all B. catarrhalis isolates and pure cultures of Hemophilus influenzae and Streptococcus pneumoniae were noted for the January 1986 to June 1989 study period. RESULTS: B. catarrhalis is now recognized as a disease-causing pathogen that is particularly noted for its association with acute otitis media in children and lower respiratory tract infections in adults with underlying cardiopulmonary disease. It was recovered from 2.7 percent of all respiratory specimens submitted over a 42-month period at this Veterans hospital. When compared with H. influenzae and S. pneumoniae, B. catarrhalis was found to be the second most commonly isolated respiratory pathogen. It was frequently found in pure culture (53 percent) or in combination with H. influenzae, gram-negative bacilli, or S. pneumoniae. The seasonal recovery of B. catarrhalis was apparent for the November to May period compared with the June to October period (p less than 0.001). CONCLUSION: B. catarrhalis has emerged as a major respiratory pathogen in pediatric and adult patient populations. There is a distinct seasonal pattern associated with its recovery and reasons for this are unclear. Prevalence studies aimed at identifying colonization rates among "low" and "high" risk groups are needed. The availability of restriction endonuclease analysis as a typing system for B. catarrhalis should favorably impact upon future epidemiologic studies. Many B. catarrhalis isolates produce beta-lactamase, and therapeutic options must reflect this.

Blastomycosis in northeast Tennessee.

STUDY OBJECTIVES: To study the epidemiologic and clinical features of blastomycosis in northeast Tennessee. DESIGN: Retrospective review of blastomycosis cases in the region from 1980 through 1995. SETTING: Hospitals located in the Tri-Cities region of northeast Tennessee. PATIENTS: Seventy-two patients with confirmed blastomycosis infection. INTERVENTIONS: None. RESULTS: During the 1980 to 1995 study period, we documented 72 cases of blastomycosis. The mean age was 52 years (range, 13 to 86 years), most were male (69.4%), and nine were immunocompromised. A possible environmental exposure was noted for 28 patients. Pulmonary involvement represented the most common site of infection (61 cases), but multiorgan involvement was common (17 cases). Most patients with pulmonary blastomycosis (66%) presented with a chronic illness, and radiologic findings usually revealed local consolidation or a mass-like lesion. Nine patients developed ARDS with an associated mortality rate of 89%, compared with a 10% mortality for non-ARDS pulmonary cases. Antifungal treatment regimens varied widely, with amphotericin B often used for sicker patients. An epidemiologic evaluation revealed that the mean yearly incidence rate for blastomycosis quadrupled between 1980 and 1987 (0.31 cases/ 100,000 population) and 1988 to 1995 (1.23 cases/100,000 population) (p=0.00001). Most new blastomycosis cases in the 1988 to 1995 period occurred in three counties in the region where significant new construction projects have been underway. CONCLUSION: Blastomycosis is endemic in northeast Tennessee and the number of cases is increasing, coinciding with major new construction in the region. Clinicians in the area must be alert to this condition.

An outbreak of Pseudomonas cepacia bacteremia associated with a contaminated intra-aortic balloon pump.

In January 1983, symptomatic Pseudomonas cepacia bacteremia developed in two patients in the cardiothoracic intensive care unit within 3 days after cardiac operation and insertion of an intra-aortic balloon pump. An epidemiologic and microbiologic investigation revealed that both patients required intra-aortic balloon pumping for circulatory support and that the water reservoir of the intra-aortic balloon pump (SMEC, Inc., Cookeville, Tenn.) contained more than 10(5) Pseudomonas cepacia per milliliter. This organism was also recovered from the purge button and on-off switch of the pump and from the hands of a health care worker who manipulated the water reservoir of the intra-aortic balloon pump. Agarose gel electrophoresis of lysates of Pseudomonas cepacia with rapid methods of deoxyribonucleic acid preparation revealed three identical plasmids of the Pseudomonas cepacia from the water reservoir of the intra-aortic balloon pump and from the infected patients. Transmission from the worker's hands to patients presumably occurred by inoculation of the intravascular lines during management. No additional cases of Pseudomonas cepacia bacteremia were observed after the unit was replaced with a nonwater reservior intra-aortic balloon pump. This report substantiates the ability of Pseudomonas cepacia to multiply in water and to cause epidemic bacteremia, identifies the water reservoir of the SMEC intra-aortic balloon pump as a previously unrecognized hazard for the patient requiring intra-aortic balloon pumping, and documents the value of plasmid analysis in elucidating the mode of transmission of nosocomial Pseudomonas cepacia infections.

Susceptibility of antibiotic-susceptible and antibiotic-resistant hospital bacteria to disinfectants.

OBJECTIVE: To evaluate whether hospital strains of antibiotic-resistant bacteria exhibited altered susceptibility to disinfectants. DESIGN: Antibiotic-susceptible bacteria were obtained from American Type Culture Collection: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Salmonella choleraesuis, and Pseudomonas aeruginosa. Hospital strains of antibiotic-resistant bacteria were obtained from clinical isolates, including: S aureus, S epidermidis, E coli, Enterococcus species, K pneumoniae, and P aeruginosa. The Association of Official Analytical Chemist's use-dilution method was used to test these 12 strains of 7 bacterial pathogens for their susceptibility to a phenol and a quaternary ammonium compound. For five pathogens, we tested a susceptible and a more resistant strain in 20 comparative trials (5 pathogens, 2 disinfectants, 2 dilutions per disinfectant). RESULTS: In our 20 comparative trials, the antibiotic-resistant strains exhibited an increased resistance to the disinfectant in only a single instance. CONCLUSIONS: Our data demonstrate that the development of antibiotic resistance does not appear to be correlated to increased resistance to disinfectants.

The epidemiology of mupirocin resistance among methicillin-resistant Staphylococcus aureus at a Veterans' Affairs hospital.

OBJECTIVE: To describe the clinical and molecular epidemiology of mupirocin-resistant (MR) and mupirocin-susceptible (MS) methicillin-resistant Staphylococcus aureus (MRSA) at a Veterans' Affairs hospital and to assess risk factors associated with the acquisition of MR MRSA. DESIGN: All clinical MRSA isolates for the period October 1990 through March 1995 underwent susceptibility testing to mupirocin. Mupirocin resistance trends were measured, and MS MRSA and MR MRSA isolates underwent typing by pulsed-field gel electrophoresis (PFGE). A retrospective case-control study was conducted to evaluate risk factors for having MR versus MS MRSA. SETTING: The James H. Quillen Veterans' Affairs Medical Center in Mountain Home, Tennessee, included a 324-bed acute-care hospital, a 120-bed nursing home, and a 525-bed domiciliary. Colonizations and infections with MRSA were endemic, and mupirocin ointment was commonly used. PATIENTS: Inpatients and outpatients at the facility. RESULTS: MS MRSA was recovered from 506 patients and MR MRSA from 126. Among MR MRSA isolates, 58% showed low-level mupirocin resistance (minimum inhibitory concentration [MIC] > or = 4 to 256 microg/mL), and 42% showed high-level mupirocin resistance (MIC > or = 512 microg/mL). A significant increase (P=.002) in the number of high-level MR isolates occurred during the 1993 to 1995 period. A case-control study showed that presence of a decubitus ulcer correlated with high-level resistant isolates (P<.05). The distribution of PFGE patterns did not differ for MR and MS MRSA CONCLUSIONS: Use of mupirocin ointment in a program aimed at managing endemic MRSA infection or colonization resulted in a significant increase in the recovery of high-level MR MRSA isolates. These isolates appeared to emerge from our existing MRSA pool. A case-control study provided few clues concerning patients likely to harbor MR MRSA. We confirmed the position that the extended use of mupirocin ointment should be avoided in settings where MRSA is endemic.

Recommendations for pregnant employee interaction with patients having communicable infectious diseases.

The transmission of communicable infectious diseases from hospitalized patients to health care providers is a well-documented phenomenon. This occurrence is of particular concern when the health care worker is a pregnant female and there is worry about the development of a congenital infection or transmission of infection at the time of delivery. Infection control practitioners and Employee Health Service personnel are often consulted by pregnant hospital employees who are concerned about interacting with patients having communicable infectious diseases, and appropriate advice is sought. Since it has often been necessary in the past to consult numerous resources in order to respond to these issues, we have compiled recommendations that can serve as a reference to help ICPs and Employee Health Service personnel deal with these situations.

Risk factors associated with post cesarean section febrile morbidity.

A high incidence of post cesarean section febrile morbidity has caused a number of investigators to recommend using prophylatic antibiotics for patients undergoing this procedure. Recent data suggest that such prophylactic antibiotics should be reserved for high-risk patients. Since previous studies have not adequately defined the high-risk patient, we analyzed 129 patients undergoing cesarean section to identify the factors which predispose to postoperative febrile morbidity. Two different statistical programs identified four factors (general anesthesia, obesity, hematocrit less than or equal to 30%, and labor prior to delivery) which were significantly associated with post cesarean section febrile morbidity (P less than 0.025). Patients with 2 or more of these risk factors were highly likely to experience this postoperative complication (P less than 0.001).

Disseminated Herpes simplex virus infection during pregnancy.

Disseminated herpes simplex virus infection during pregnancy is uncommon but is accompanied by high maternal and fetal morbidity and mortality. Pregnant women with primary mucous membrane infection during the third trimester may run an increased risk for dissemination, although specific predisposing factors are unknown. Diagnosis requires awareness of the clinical syndrome, a high index of suspicion in the proper setting, and appropriate use of available diagnostic techniques. Although the disease may be self-limited, mortality approaches 40% for mother and fetus. In the presence of severe or progressive systemic infection, specific antiviral chemotherapy with vidarabine may be warranted. Management of the fetus remains problematic; prompt delivery by cesarean section may be indicated.

Prophylactic antibiotics in high-risk cesarean section.

A brief perioperative course of ampicillin was recommended for high-risk patients undergoing cesarean section at our institution. High-risk patients were defined as those with two or more of the following factors: general anesthesia, obesity, hematocrit less than or equal to 30%, and labor prior to delivery. Fifteen percent of high-risk patients who received prophylactic antibiotics experienced postoperative febrile morbidity compared to 63% for the high-risk untreated group (P less than 0.001). Twenty-five percent of low-risk patients (less than 2 risk factors) developed this complication. Endometritis was the leading cause of postoperative febrile morbidity. Postoperative stay was only slightly decreased in the prophylactically treated group (5.9 vs 6.2 days). Prophylactic amplicillin given perioperatively was an effective agent in reducing post-cesarean-section febrile morbidty among high-risk patients.

Factors associated with nephrotoxicity and clinical outcome in patients receiving amikacin.

Data from 60 patients treated with amikacin were analyzed for factors associated with nephrotoxicity. In 42 of these patients, data were examined for factors associated with clinical outcome. Variables evaluated included patient weight, age, sex, serum creatinine level, creatinine clearance, duration of therapy, total dose, mean daily dose, organism minimum inhibitory concentration (MIC), mean peak levels, mean trough levels, mean area under the serum concentration-time curve (AUC), total AUC, mean AUC greater than MIC, total AUC greater than MIC, mean Schumacher's intensity factor (IF), total IF, In (mean maximum concentration [Cmax]/MIC). Model-dependent pharmacokinetic parameters were calculated by computer based on a one-compartment model. When the parameters were examined individually, duration of therapy and total AUC correlated significantly (P less than .05) with nephrotoxicity. In contrast, a stepwise discriminant function analysis identified only duration of therapy (P less than .001) as an important factor. Based on this model and on Bayes' theorem, the predictive accuracy of identifying "nephrotoxic" patients increased from 0.17 to 0.39. When examined individually, mean IF, MIC, total dose, mean daily dose, and ln (mean Cmax/MIC) correlated significantly (P less than .05) with cure. In contrast, a simultaneous multivariable analysis identified IF, MIC, and total dose according to one model and ln (mean Cmax/MIC) according to a second statistical model of parameters selected to have the greatest prospective value. Based on Bayes' theorem and the first model, the predictive accuracy of identifying patients not cured increased from 0.19 to 0.83. For the second model, the predictive accuracy increased from 0.19 to 0.50.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of lower respiratory tract infections with cefoperazone.

Fifteen patients with documented bacterial lower respiratory tract infections were treated with cefoperazone (2 gm every 12 hours, administered parenterally) as the single antibiotic therapy. Pulmonary infections included pneumonia (10), anaerobic lung abscess (2), bronchitis (2), and exacerbation of bronchiectasis (1); most of the patients had concomitant illnesses that compromised their host-immune status. Bacteria recovered from respiratory tract cultures included aerobic gram-negative bacilli (17), anaerobes (6), and aerobic gram-positive cocci (3). After therapy, lasting 5 to 28 days, nine patients had complete resolution of their infection, and the remaining six patients had significant clinical improvement. Diarrhea was the adverse reaction most commonly noted; others included an unusual reaction resembling serum sickness, and, in one patient treated for 24 days, hypotension and a subsequent decrease in renal function. Drug-related abnormalities in blood and serum values were few and mild. Cefoperazone was found to be effective in the treatment of lower respiratory tract infections.

Serious postoperative infections caused by coagulase-negative staphylococci: an epidemiological and clinical study.

We have reviewed all 3577 nosocomial infections occurring at our institution over a 49-month period and found coagulase-negative staphylococci (CNS) associated with 297. Seventy-eight of 193 CNS tested for antibiotic sensitivity were multiple-drug resistant (MR-CNS). There were 19 well-documented serious postoperative CNS infections including nine ventricular, seven bloodstream and three peritoneal infections. Each was associated with an indwelling device and 11 of the infections involved MR-CNS. Antibiotic therapy with or without removal of the device resulted in cure of all patients. Air samples taken during various surgical procedures frequently were positive for CNS but rarely revealed MR-CNS. Our results cause concern regarding current antibiotic prophylaxis regimens.

Nosocomial transmission clusters and risk factors in Moraxella catarrhalis.

We report an objective examination of nosocomial transmission events derived from long-term (10-year) data from a single medical centre. Cluster analysis, based on the temporal proximity of genetically identical isolates of the respiratory pathogen Moraxella catarrhalis, identified 40 transmission events involving 33 of the 52 genotypes represented by multiple isolates. There was no evidence of highly transmissible or outbreak-prone genotypes. Although most clusters were small (mean size 3.6 isolates) and of short duration (median duration 25 days), clustering accounted for 38.7% of all isolates. Significant risk factors for clustering were multi-bed wards, and winter and spring season, but bacterial antibiotic resistance, manifested as the ability to produce a beta-lactamase was not a risk factor. The use of cluster analysis to identify transmission events and its application to long-term data demonstrate an approach to pathogen transmission that should find wide application beyond hospital populations.