In vitro bactericidal effect of a modified thermal Nitinol electrode.

PURPOSE: A standard electrode surgical generator connected to a Nitinol coil was used in vitro to evaluate whether the generated electromagnetic energy had any bactericidal effect on Escherichia coli. MATERIALS AND METHODS: The ATCC 259222 E. coli strain was used. We mixed 135 mL of a 1.5% non-nutritive agar with 15 mL of a 10(6) CFU/mL inoculum and transferred it to gas-sterilized plastic containers lined with aluminium foil. A 22F cylindrical shape was cut from the center of the agar, and a Nitinol coil was placed in that space and connected to a standard electrode surgical generator. Electrical energy was then applied from 5 to 25 V at 5-V increments. Temperatures were measured with two thermocouples placed in the middle and periphery of each agar. The treatment was stopped when the temperature at the middle thermometer reached 50 degrees C. The control group was not treated and was embedded in a water bath at 45 degrees C. Three 3 x 7-mm pieces were sliced from the inner to the outer part of the agar and processed, and colony counts were performed. RESULTS: We observed statistically significant deleterious effects on E. coli in all three zones when the treatment voltage was 15 and 20. When the potential was raised to 25 V, we observed a significant result only in the core zone. The treatment duration was 50 minutes for 5 and 10 V, 45 minutes for 15 V, 15 minutes for 20 V, and 10 minutes for 25 V. CONCLUSION: The bactericidal effect was mainly in the central area, decreasing linearly toward the periphery, and was related to the temperature reached during activation of the electrical generator. These results were disappointing with regard to the utility of Nitinol stents to treat bacterial prostatitis.

Bacterial colonization of endotracheal tubes in intubated neonates.

OBJECTIVE: To obtain in vivo bacterial colonization profiles on endotracheal tubes at different sites in the neonatal airway in an attempt to better characterize one potential element of chondritis. DESIGN: A case series in which cultures were obtained from calculated segments of 33 endotracheal tubes immediately following extubation. This allowed for sampling at specific levels of the airway corresponding to the trachea, the subglottis, and the oropharynx. Data collected included gender, race, duration of intubation, use of antibiotic therapy, comorbidities, gestational age at birth and extubation, crown-rump length, weight, radiographic distance from tube tip to carina, and culture results. SETTING: Newborn intensive care unit at a tertiary care medical center. PATIENTS: Twenty-nine neonates intubated for longer than 24 hours (range, 24 hours to 15 days). MAIN OUTCOME MEASURES: Bacterial and fungal cultures obtained from 3 endotracheal tube segments for each extubation. RESULTS: A statistically significant difference (P < .05) was found in colonization rates between patients intubated for less than 4 days and those intubated for longer periods. No significant difference was noted in bacterial profile between the 3 sites. CONCLUSIONS: Data demonstrate that bacterial colonization of an indwelling object in the neonatal airway increases with the duration of intubation. Furthermore, 4 days seems to represent a critical period in the formation of such colonization (possibly in the form of a biofilm). These bacteria may contribute to the chondritis known to precede the development of subglottic stenosis. Further studies are indicated to suggest ways to interrupt this process and reduce the incidence of airway injury.

Mortality associated with concurrent strongyloidosis and cytomegalovirus infection in a patient on steroid therapy.

Disseminated strongyloidosis has been recognized with increasing frequency, often in patients who are immunocompromised or have received steroid therapy. In addition, disease due to cytomegalovirus (CMV) is noted in immunodeficient hosts. We report on a 55-year-old Puerto Rican man who received steroid treatment for orpharyngeal pemphigus vulgaris and developed abdominal symptoms with alternating constipation and diarrhea. The clinical work-up did not reveal specific abnormalities, but the patient died of cardiopulmonary failure. At the postmortem examination, the patient had evidence of strongyloidosis and CMV disease. This report reviews both this case and the literature, and discusses the overlapping infections of strongyloidosis and CMV disease in this patient who had received steroid therapy.

In vitro activity of ciprofloxacin, levofloxacin, and trovafloxacin, alone and in combination with beta-lactams, against clinical isolates of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Burkholderia cepacia.

We tested three fluoroquinolones (ciprofloxacin, levofloxacin, and trovafloxacin), each combined with each of four beta-lactams (cefoperazone, ceftriaxone, imipenem, and meropenem) for synergy against clinical isolates of nosocomial strains of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Burkholderia cepacia. The ciprofloxacin-beta-lactam combinations showed synergy against none or only a small fraction (7 to 10%) of the P. aeruginosa and B. cepacia isolates. Ciprofloxacin-cefoperazone, -ceftriaxone, and -meropenem were synergic against 50%, 25%, and 30% of the S. maltophilia isolates, respectively. Among the levofloxacin combinations, only those with cefoperazone and imipenem showed significant synergy, and this only against B. cepacia (50% and 30%, respectively). Trovafloxacin-cefoperazone and -imipenem showed modest synergy against P. aeruginosa (23% and 27%, respectively), as did trovafloxacin-cefoperazone and -ceftriaxone against B. cepacia (30%). The trovafloxacin-imipenem combination was synergic against all isolates of B. cepacia. Because of their synergy, the following combinations may be useful in the nosocomial setting: trovafloxacin-cefoperazone or -imipenem against P. aeruginosa; ciprofloxacin-cefoperazone, -ceftriaxone, or -meropenem against S. maltophilia; levofloxacin-cefoperazone and trovafloxacin-imipenem against B. cepacia.

In vitro susceptibility of recent gram-positive isolates to ciprofloxacin, levofloxacin, and trovafloxacin.

Gram-positive isolates (n = 290) were tested for their susceptibility to three fluoroquinolone antibiotics by standard disk-diffusion technology. Overall, 59%, 72%, and 85% were susceptible and 29%, 25%, and 11% were resistant to ciprofloxacin, levofloxacin, and trovafloxacin, respectively. Of Staphylococcus aureus isolates (n = 84), 55%, 57%, and 88% were susceptible to the three antibiotics, respectively. Staphylococcus epidermidis (n = 45), too, was more susceptible to trovafloxacin, although the differences were smaller (60%, 62%, and 78%). Of 35 Enterococcus faecalis isolates, 66% and 74% were susceptible to levofloxacin and trovafloxacin, respectively, but only 9% were susceptible to ciprofloxacin.

The in vitro bactericidal effect of microwave energy on bacteria that cause prostatitis.

OBJECTIVES: We investigated the in vitro nonthermal effects of microwaves delivered from Prostatron 2.0 on Escherichia coli and Enterobacter cloacae. METHODS: The fingers of powder-free, sterile gloves were ligated, and bacterial solutions were transferred into the remaining area of the glove. The gloves were then sealed using silk ligatures. One set of gloves was subjected to the microwave treatment while another set was placed in a temperature-matched waterbath to act as control samples. The gloves containing the treatment group were taped around the probe, at the site where microwave energy exits the probe. During the treatment period, the temperatures from the urethral probe and the rectal probe were carefully monitored. RESULTS: The mean (+/-SD) energy delivered was 46.6 +/- 9.5 kJ (range 30.0 to 59.5) for the 10 trials on E. coli and colony counts in the experimental microwaved gloves decreased significantly compared with control samples (5.26 +/- 4.5 x 10(5) versus 10.16 +/- 9.3 x 10(5) CFU/mL, P = 0.02). For the experiments on E. cloacae the mean (+/-SD) energy applied was 38.5 +/- 12.5 kJ, and a significant decrease in colony counts of microwaved samples was also observed compared with controls (11.04 +/- 4.8 x 10(5) versus 20.08 +/- 10.1 x 10(5) CFU/mL, P = 0.004). CONCLUSIONS: Microwave energy, delivered from Prostatron 2.0, independent of heat production has an in vitro bactericidal effect on laboratory-cultured E. coli and E. cloacae.

Epidemiology and control of vancomycin-resistant enterococci in an adult and children's hospital.

BACKGROUND: The incidence of vancomycin-resistant enterococci (VRE) has reached endemic proportions in many medical centers. To initiate an effective infection control program, an understanding of the epidemiologic attributes of the genus in medical facilities is imperative. METHODS: We studied 138 consecutive cases of VRE from April through December 1995. We created a database to analyze the risk factors for patients in both an adult hospital and a children's hospital and screened all specimens, submitted for routine microbiologic analysis, for VRE. RESULTS: One hundred twenty-three cases (89%) occurred in the adult acute care hospital, and 15 (11%) occurred in the children's hospital. Eighty patients (58%) were colonized with VRE, and 58 (42%) had an infection with VRE. Eighty-three percent of all the cases of VRE were nosocomially acquired. The majority of cases occurred in the medical service. Urine was the most important clinical specimen infected or colonized. Prior use of an antibiotic, other than vancomycin, was the most important risk factor for all nosocomial cases, followed by prior vancomycin use for surgical patients and residence in a unit with other patients infected with VRE for the medical service. Direct admission from another hospital was the most important risk factor for community-acquired cases. Special microbiologic screening of cultures yielded 48% of all VRE identified. Enterococcus faecium was the predominant resistant isolate recovered. CONCLUSIONS: The control of VRE in the hospital setting is difficult for several reasons. Almost half of all patients carrying VRE would not have been identified without special microbiologic screening efforts, as would patients, admitted from the community, who are already colonized with VRE. Controlling antibiotic use both in the hospital and the community is basic for controlling these organisms. Continuous education of all staff about VRE and other nosocomially significant organisms is the key to controlling the spread of these bacteria.

Response of enteric gram-negative bacteria to disks containing 20 micrograms each of ampicillin and sulbactam.

Ampicillin-sulbactam disks containing either 10 microg of each drug or 20 microg of each drug were tested against 138 recently, sequentially isolated members of the family Enterobacteriaceae. Results obtained with the higher-content disks corresponded more closely to the impressions of clinicians.

Gemella morbillorum as a cause of septic shock.

The gram-positive bacterium Gemella morbillorum has been recovered from patients with endocarditis but has rarely been associated with acute fulminant infections. We describe two children with a rapid onset of septic shock, which was fatal in one, following infection with this organism. G. morbillorum is a commensal organism of the upper respiratory tract; it gained access to the bloodstreams in these patients, and bacteremia occurred. A clinical drawback is that the initial colonial morphology of this organism leads to presumptive identification as a viridans streptococcus, an organism not commonly associated with septic shock syndrome. Resistance of G. morbillorum to penicillin appears to be common; therefore, initial empirical combination therapy (a beta-lactam agent and an aminoglycoside) or vancomycin treatment should be considered.

Susceptibility testing of Propionibacterium acnes comparing agar dilution with E test.

Propionibacterium acnes has been identified as a significant agent of nosocomial infections, including endophthalmitis. Data concerning susceptibility of P. acnes to newer beta-lactam antibiotics and fluoroquinolones are limited. Recent reports suggest that quinolones have activity against these organisms sufficient to warrant further study. We undertook a study to select appropriate antimicrobial agents for use in a rabbit model of P. acnes endophthalmitis. We compared the antibiotic susceptibilities of P. acnes by using the National Committee for Clinical Laboratory Standards method of agar dilution with the E test. Thirteen clinical isolates obtained from eye specimens and three American Type Culture Collection control strains were tested against 14 antibiotics. All the clinical isolates were susceptible by both methods to piperacillin, piperacillin-tazobactam, ampicillin-sulbactam, ticarcillin-clavulanate, cefotaxime, cefotetan, ceftriaxone, cefoxitin, and imipenem in addition to clindamycin but were resistant to metronidazole. The clinical P. acnes isolates also displayed high-level susceptibility to ciprofloxacin, sparfloxacin, and ofloxacin. Almost all the P. acnes strains demonstrated E-test MICs within 2 dilutions of the MICs observed by the agar dilution method. Those few strains for which discrepancies were noted exhibited E-test susceptibilities three- to fivefold dilutions lower than the agar dilution method susceptibilities but only with ampicillin-sulbactam, ticarcillin-clavulanate, and/or clindamycin. On the basis of our study, all of clinical eye isolates were susceptible to these newer antimicrobial agents and the two methods demonstrated similar susceptibility patterns.

Association of recurrent candidal vaginitis with inheritance of Lewis blood group antigens.

A subset of women with candidal vulvovaginitis have no known risk factors for recurrent episodes. Although there are reports of an association of blood group antigens with various infections, no such association has been described with candidal vulvovaginitis. The ABO, P1, and Lewis group phenotypes of 35 women with recurrent vulvovaginitis but without other chronic infections were determined. These were compared with those of a control group of 40 women without a history of candidal vulvovaginitis. The distribution of ABO blood types and P blood group phenotype did not differ from those in controls. However, vulvovaginitis patients were more likely than controls to be classified as Lea-b- (chi 2 = 6.4, 1 df, P = .011). Women without known predisposing factors may have a genetic predisposition to recurrent vulvovaginitis, as evidenced by a higher frequency of Lea-b- phenotype profiles compared with controls.

Characterization of vancomycin resistance in Enterococcus durans.

During investigation of an outbreak of vancomycin resistant Enterococcus faecium in a paediatric hospital, an isolate of Enterococcus durans resistant to vancomycin, teicoplanin, ampicillin and highly resistant to gentamicin and streptomycin was found in the stools of a patient also colonized with a strain of E. faecium with the same resistance pattern. Minimal inhibitory concentrations of vancomycin and teicoplanin were 512 and 64 mg/mL, respectively. Resistance to vancomycin as well as high-level resistance to gentamicin was transferable to an E. faecium recipient strain. Both multiresistant E. faecium and E. durans isolates as well as the transconjugant presented only one plasmid. The vanA gene was detected and localized to the high molecular weight plasmid by DNA hybridization with a vanA gene probe. Growth in vancomycin resulted in induction of an approximately 40 kDa protein visible in membrane preparations from these cells. Genetic linkage between vancomycin and gentamicin resistance genes in the same plasmid is suggested.

Is hand washing really needed in an intensive care unit?

OBJECTIVES: To determine whether a rigorous antiseptic hand washing of bare hands with 4% chlorhexidine and alcohol reduced fingertip microbial colonization as compared with the use of boxed, clean, nonsterile latex gloves. In addition, to investigate if aseptic donning technique and/or a prior hand washing would reduce the level of glove contamination. DESIGN: Prospective, randomized, crossover design, with each subject serving as his/her own control. SETTING: University intensive care unit. SUBJECTS: Forty-three intensive care nurses. INTERVENTIONS: The fingertips of 20 nurses were cultured before and after a strict antiseptic hand washing and before and after the routine and aseptic donning of sterile gloves. Subsequently, the fingertips of 43 nurses were cultured before and after the casual donning of nonsterile gloves over unwashed hands and before and after a strict antiseptic hand washing. Fingertip cultures were plated directly on agar, incubated for 24 hrs, and counted and recorded as the number of colony-forming units (cfu) for each hand. Different colony types were then subcultured. MEASUREMENTS AND MAIN RESULTS: Hand washing with antiseptic reduced colonization from 84 to 2 cfu (p < .001). The proportion of cases with > or = 200 cfu/hand was reduced from 30% to 9%. Aseptic or casual donning of sterile gloves, with or without prior antiseptic hand washing, resulted in consistently low glove counts between 0 and 1.25 cfu. Nonsterile gloves casually donned over washed or unwashed bare hands diminished the bioburden to 2.17 and 1.34 cfu, respectively. No qualitative difference was found in the microorganisms recovered from gloved or bare hands. CONCLUSIONS: Antiseptic hand washing and the use of nonsterile gloves over unwashed hands confer similar reductions in the number of microorganisms. There is no additional benefit with the use of aseptic donning technique, prior antiseptic hand washing, or the use of individually packaged sterile gloves.

The challenge of vancomycin-resistant enterococci: a clinical and epidemiologic study.

BACKGROUND: Vancomycin-resistant enterococci have been recovered with increasing frequency from hospitalized patients. Risk factors, mode of nosocomial transmission, extent of colonization in hospitalized patients, and treatment options for these organisms have not been completely delineated. METHODS: We studied 53 patients (group A) with vancomycin-resistant enterococci isolated from various clinical specimens and also surveyed for vancomycin-resistant enterococci in stool specimens submitted for Clostridium difficile toxin assays (group B). Stool specimens submitted for identification of bacterial pathogens and stool specimens from hospital employees were also analyzed for vancomycin-resistant enterococci. RESULTS: Seventy-six isolates of vancomycin-resistant enterococci were recovered in group A. Five of these patients harbored vancomycin-resistant enterococci on admission. Fifty-three of 289 group B stool specimens submitted for C. difficile toxin assays yielded vancomycin-resistant enterococci. Cephalosporins and vancomycin were the most common antimicrobial agents received by both groups of patients. Enterococcus faecium isolates were more resistant than Enterococcus faecalis isolates to antimicrobial agents. All isolates exhibited high-level aminoglycoside resistance and were not beta-lactamase producers. There were at least 15 different molecular clones of E. faecium and three of E. faecalis. Vancomycin-resistant enterococcal bacteremia was associated with a 100% in-hospital mortality rate. CONCLUSIONS: Multidrug-resistant and vancomycin-resistant enterococci have become important nosocomial pathogens that are difficult to treat. Vancomycin-resistant enterococcal bacteremia was associated with a poor prognosis. We found a high rate of colonization in patients with suspected C. difficile toxin colitis. Judicious use of vancomycin and broad-spectrum antibiotics is recommended, and strict infection control measures must be implemented to prevent nosocomial transmission of these organisms.

Clostridium bifermentans bacteremia with metastatic osteomyelitis.

Osteomyelitis caused solely by an anaerobic organism is uncommon. We report a case of recurrent Clostridium bifermentans bacteremia resulting in metastatic osteomyelitis involving the sacrum, spine, and ribs. The emergence of resistance of this organism to imipenem and metronidazole is noteworthy because of the usual susceptibility of clostridial species to these antibiotics.