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Prevalence of antimicrobial resistance in bacteria isolated from central nervous system specimens as reported by U.S. hospital laboratories from 2000 to 2002.

BACKGROUND: Bacterial infections of the central nervous system, especially acute infections such as bacterial meningitis require immediate, invariably empiric antibiotic therapy. The widespread emergence of resistance among bacterial species is a cause for concern. Current antibacterial susceptibility data among central nervous system (CNS) pathogens is important to define current prevalence of resistance. METHODS: Antimicrobial susceptibility of pathogens isolated from CNS specimens was analyzed using The Surveillance Database (TSN) USA Database which gathers routine antibiotic susceptibility data from >300 US hospital laboratories. A total of 6029 organisms derived from CNS specimen sources during 2000-2002, were isolated and susceptibility tested. RESULTS: Staphylococcus aureus (23.7%) and Streptococcus pneumoniae (11.0%) were the most common gram-positive pathogens. Gram-negative species comprised approximately 25% of isolates. The modal patient age was 1 or <1 year for most organisms. Prevalence of MRSA among S. aureus from cerebrospinal fluid (CSF) and brain abscesses were 29.9-32.9%. Penicillin resistance rates were 16.6% for S. pneumoniae, 5.3% for viridans group streptococci, and 0% for S. agalactiae. For CSF isolates, ceftriaxone resistance was S. pneumoniae (3.5%), E. coli (0.6%), Klebsiella pneumoniae (2.8%), Serratia marcescens (5.6%), Enterobacter cloacae (25.0%), Haemophilus influenzae (0%). Listeria monocytogenes and N. meningitidis are not routinely susceptibility tested. CONCLUSIONS: Resistance is commonly detected, albeit still at relatively low levels for key drugs classes such as third-generation cephalosporins. This data demonstrates the need to consider predominant resistance phenotypes when choosing empiric therapies to treat CNS infections.

Journal Article↗

The non-value of preoperative and intraoperative cultures in predicting the bacteriology of subsequent wound infection in patients undergoing major head and neck cancer surgery.

A prospective study of patients undergoing major head and neck cancer surgery was undertaken to define the value of preoperative and intraoperative cultures in identifying the patient at "high risk" of wound infection and in predicting the bacteriology of wound infection. One or two days before surgery, the skin of the operative site on the neck, the oropharynx and anterior nares were swabbed. an intraoperative wound culture was obtained after the pharyngeal defect was closed and the wound irrigated with water. All cultures were processed for aerobes in the Anaerobic Bacteriology Research Laboratory at Wadsworth Hospital Center. Wound infections developed in 10 of 31 patients who received cefazolin prophylactically and 21 of 25 patients who received no perioperative antibiotics. Fifty-five percent of infected patients and 68% of noninfected patients demonstrated potential pathogens preoperatively. A potential pathogen isolated preoperatively or intraoperatively was subsequently recovered from 35% of infected wounds. The majority of infected wound cultures grew one or more additional pathogens. A poor correlation was also noted between preoperative nasal Staphylococcus aureus isolation and subsequent recovery from wound infections. We conclude that preoperative and intraoperative aerobic wound cultures are not predictive of the "high risk" patient or of the bacteriology of subsequent wound infection in major head and neck cancer surgery.

Bacteriological Techniques↗

Characterization of the multiple-copy host-selective toxin gene, ToxB, in pathogenic and nonpathogenic isolates of Pyrenophora tritici-repentis.

ToxB, a gene that encodes a 6.6-kDa host-selective toxin (HST), is present in several races of the wheat pathogen Pyrenophora tritici-repentis. To learn more about the multiple ToxB open reading frames (ORFs), six of the estimated nine copies from a race 5 isolate were cloned and analyzed. All six copies of ToxB have identical 261-bp ORFs and thus encode the same form of Ptr ToxB. Sequence analysis of regions flanking the cloned ToxB loci revealed that the majority of loci are associated with portions of retrotransposons and a transposon-like sequence. Data indicate that ToxB loci reside on two chromosomes, 3.5 and 2.7 Mb, with the majority of copies located on the 2.7 Mb chromosome. A related gene, referred to as toxb, from a nonpathogenic race 4 isolate was also cloned and characterized. This is interesting because, until now, HST genes have only been found in toxin-producing, pathogenic isolates of plant pathogenic fungi. The toxb gene from nonpathogenic isolates is 86% similar to ToxB, and data suggest that toxb is a single-copy gene. No toxb transcript was detected under culture conditions that favor the expression of ToxB; therefore, these genes differ in their transcriptional regulation.

Amino Acid Sequence↗

Laboratory data from the surveillance of a burns ward for the detection of hospital infection.

Nosocomial infection is a major problem affecting many hospital personnel and patients. Surveillance of intensive care areas such as burns wards is important due to the immunocompromised status of the patients. Since infection has been found to be a major cause of death in our burns ward, bacteriological surveillance of the area was carried out over a 1-year period. This indicated the various sources of infection, which included a contaminated container of disinfectant, and transient pathogenic flora on one of the staff members involved in changing dressings. Pseudomonas aeruginosa was the most commonly isolated pathogen from infected wounds as well as from the blood of patients developing sepsis. Autogenous spread of this organism was confirmed by similar pyocin typing results of the strains isolated from wounds, blood and faeces of the patients. Necessary changes were implemented based on these findings and the infection rate was reduced remarkably. The results suggested that strict vigilance by the personnel involved in the care of burns patients reduces the incidence of invasive sepsis and shortens the hospital stay.

Adolescent↗

[Antimicrobial susceptibilities of organisms isolated from patients with urinary tract infections in 2002].

Using the agar dilution method, the antibacterial activity of 18 antibiotics inclusive of 4 carbapenems were investigated against 101 strains of urinary pathogens isolated from patients with urinary tract infections who visited the Department of Urology at Kagoshima University Hospital, between January and December 2002. 4 strains of Staphylococcus aureus, 3 strains of Staphylococcus spp. (exclusive of S. aureus), 14 strains of Enterococcus faecalis, 3 strains of Enterococcus spp. (exclusive of E. faecalis), 41 strains of Escherichia coli, 21 strains of Enterobacteriaceae (exclusive of E. coli), 12 strains of Pseudomonas aeruginosa and 3 strains of glucose-nonfermentative Gram-negative rods (exclusive of P. aeruginosa) were examined. 1. Against clinical isolates of Gram-positive bacteria, vancomycin and teicoplanin were active. Additionally, arbekacin was active against S. aureus clinical isolates and ampicillin was active against E. faecalis clinical isolates. Carbapenems were active against clinical isolates of Gram-positive bacteria, except for multi-drug resistant strains of Gram-positive bacteria, such as methicillin-resistant S. aureus. 2. As for clinical isolates of Gram-negative bacteria, meropenem was most active against Enterobacteriaceae among 13 antibiotics tested. Against P. aeruginosa clinical isolates, MIC90 of meropenem was the lowest among 13 antibiotics tested. In addition, resistant rate of meropenem and biapenem against P. aeruginosa clinical isolates was lower than those of the other carbapenems tested. 3. As main urinary pathogens showed no remarkable increase in resistance to carbapenems, it can be stated that carbapenems retain their position as the drug of first choice for severe infection.

Anti-Bacterial Agents↗

Total parenteral nutrition-related infections. Prospective epidemiologic study using semiquantitative methods.

Studies of total parenteral nutrition-related infection have incorrectly relied on positive results on culture of the cannula tip to confirm the source. We undertook a prospective study of total parenteral nutrition-related infections in adult patients by obtaining blood from all total parenteral nutrition lines for pour-plate culture twice weekly and culturing intravascular line segments by the technique of Maki. Twelve of 100 courses of total parenteral nutrition (12 percent) in 69 patients resulted in infections--five (5.0 percent) had sepsis, and seven (7.0 percent) had local infection. In five of these 12, pour-plate culture gave positive results (five of 38 pour plates) with counts of 8 colony-forming units per ml (cfu/ml) for Candida tropicalis, and 25 to more than 1,000 for bacterial isolates. In nine of 12, culture of the intravascular line segment gave positive results with more than 50 cfu/ml. Pathogens isolated from intravascular line segments included Staphylococcus epidermidis (three cases), Candida species (three cases), Staphylococcus aureus (two cases), Serratia marcescens (one case) and mixed bacterial pathogens (one case). In contrast, pour-plate culture gave positive results in only seven of 88 uninfected (control) courses (318 pour plates), and culture of intravascular line segments gave positive results in two of 65 uninfected courses (p less than 0.001). No differences existed among patients with and without infection with regard to age, underlying disease, surgery, systemic antibiotic usage, or the presence of other infections. The duration of total parenteral nutrition was longer in courses without infection than in courses with infection (14.7 +/- 9.4 days versus 11.0 +/- 4.0 days; p less than 0.02). In six of 12 courses with infection, the line had been violated compared with 22 of 88 courses without infection (p less than 0.001). T-connectors for the centra administration of intralipid were associatd with infection (p less than 0.02). The value of routine pour-plate culture was illustrated in three courses in which the positive pour-plate culture results antedated positive blood culture results or line removal.

Bacterial Infections↗

Antigenic variations in the CD4 induced sites of the CCR5-tropic, pathogenic SHIVsf162p3 gp120 variants.

In vivo passage of non-pathogenic, CCR5-tropic simian/human immunodeficiency virus (SHIV) - SHIVsf162 resulted in a pathogenic isolate, SHIVsf162p3. In an attempt to characterize envelope (Env)-mediated properties that may contribute to its pathogenicity, major (P3 major) and minor (P3 minor) Env gp120 variants were cloned from the plasma of a SHIVsf162p3-infected animal, and expressed in the context of luciferase reporter viruses. Entry mediated by these envelopes and susceptibility to neutralization by CD4 induced-site (CD4i) antibodies (MAbs) was analyzed in comparison to parental SF162. Sequence analysis revealed that the P3 major and minor variant Envs contained 14 and 17 amino acid changes, respectively, compared with SF162. The rank order of entry mediated by the three envelopes was P3 major > SF162 > P3 minor, whereas the reverse order was observed for susceptibility to neutralization by CD4i MAbs. Since CD4i epitopes overlap the coreceptor (CoR) binding site, these findings suggest that the amino acid changes accumulated upon in vivo passage of SHIVsf162 result in Env gp120 structural rearrangements that modulate the exposure and/or conformation of the CoR binding site. This, in turn, led to increased entry and infectivity of the P3 major variant and may be responsible, in part, for the enhanced pathogenicity of SHIVsf162p3.

Amino Acid Sequence↗

Diagnosis and treatment of catheter-related infections in paediatric oncology: an update.

Otherwise unexplained clinical signs of infection in patients with long-term tunnelled or totally implanted central venous access devices (CVADs) are suspected to be CVAD-associated. Diagnostic methods include catheter swabs, blood cultures and cultures of the catheter tip or port reservoir. In the case of a suspected CVAD-related bloodstream infection in paediatric oncology patients, in-situ treatment without prompt removal of the device can be attempted. Removal of the CVAD should be considered if bacteraemia persists or relapses > or = 72 h after the initiation of (in-vitro effective) antibacterial therapy administered through the line. Timely removal of the device is also recommended if the patient suffers from a complicated infection, or if Staphylococcus aureus, Pseudomonas aeruginosa, multiresistant Acinetobacter baumannii or Candida spp. are isolated from blood cultures. Duration of therapy depends on the immunological recovery of the patient, the pathogen isolated and the presence of related complications, such as thrombosis, pneumonia, endocarditis and osteomyelitis. Antibiotic lock techniques in addition to systemic treatment are beneficial for Gram-positive infections. Although prospectively controlled studies are lacking, the concomitant use of urokinase locks and taurolidine secondary prophylaxis seem to favour catheter salvage.

Acridine Orange↗

[Treatment of bronchopulmonary infections in patients during artificial respiration with imipenem/cilastatin].

In an open prospective study the efficacy and tolerance of imipenem/cilastatin was investigated in 24 critically ill patients on mechanical ventilation with nosocomial respiratory tract infection. Nine patients had previously received antibiotic therapy which had failed. Imipenem was given in a dose of 1-3g/24 h over 5-37 (mean 11) days. Seven patients were additionally treated with aminoglycosides, one patient with erythromycin. Pseudomonas aeruginosa, Staphylococcus aureus, Hemophilus influenzae and Escherichia coli were the most frequently isolated pathogens from tracheobronchial secretions. 91% of the infections without and 77% with involvement of Pseudomonas aeruginosa were successfully treated. All of the gram-positive and 85% of the gram-negative pathogens (Pseudomonas not included) were eliminated in the course of therapy. By contrast, 64% of the isolates of Pseudomonas aeruginosa persisted; half of these became imipenem-resistant. Nine patients showed adverse reactions including one case of pseudomembranous colitis which were reversible. Imipenem/cilastatin proved highly effective and was relatively well tolerated; limitations in the efficacy were seen in cases of infection due to Pseudomonas aeruginosa.

Adolescent↗

[Frequency of isolation and drug resistance of bacterial strains isolated from respiratory material in patients with cystic fibrosis].

During 1985, 251 respiratory samples from 61 patients were examined at the tuscan cystic fibrosis Center (Florence), and isolated strains were tested against various antimicrobial drugs. Pseudomonas aeruginosa and Staphylococcus aureus were the predominant pathogens isolated. Infections caused by St. aureus were the commonest during the first years of life, whereas those caused by Ps. aeruginosa, occasional at early age, became chronic and the main source of infection with growth. Sensitivity testings against antibiotics confirmed that Ps. aeruginosa isolated from cystic fibrosis patients has a high percentage of resistant strains. The most active drugs were ceftazidime and aztreonam. An increased resistance to aminoglycosides was observed.

Adolescent↗

A sequential study of intravenous and oral fleroxacin in the treatment of complicated urinary tract infection.

This study enrolled patients with complicated urinary tract infections (UTIs) in a trial to determine the efficacy and safety of sequential therapy with intravenous fleroxacin (first 3 days) followed by oral fleroxacin, for a total course of 7-14 days, both administered at a dosage of 400 mg once a day. We enrolled 68 patients with complicated UTIs or acute pyelonephritis, 32 of whom were evaluable for bacteriologic and clinical efficacy. The pathogens isolated included Escherichia coli, 15; enterococci, 9; miscellaneous, 15. Intravenous fleroxacin was given for a mean of 3.2 days, followed by oral fleroxacin for a mean of 5.3 days. A total of 27 patients were clinically cured (84%), two improved, and three failed. A total of 26 patients were bacteriologically cured (81%), and six failed (19%). The bacteria that were not eradicated included enterococci, 4; Staphylococcus epidermidis, 1; and Pseudomonas species, 1. One enterococcal isolate became resistant to fleroxacin. Four patients were bacteremic (E. coli, 3; Proteus mirabilis, 1); the pathogen was eradicated in all cases. Two patients developed urinary enterococcal superinfections. A total of 12 patients experienced 16 adverse reactions remotely, possibly, or probably related to fleroxacin (insomnia, 3; dizziness, 2; miscellaneous, 11). One patient had a grand mal seizure after aspirating gastric contents; the seizure was thought to be only remotely related to the study drug. Fleroxacin was discontinued in two patients because of adverse effects (phlebitis at intravenous access site, 1; anxiety and insomnia, 1). Only minor and asymptomatic laboratory abnormalities were observed. All clinical and laboratory abnormalities resolved with discontinuation of the study drug. Fleroxacin is a safe and effective antibiotic for sequential intravenous and oral treatment of acute pyelonephritis and complicated UTIs. Enterococci may be problematic pathogens, as reported with other fluoroquinolones.

Administration, Oral↗

Hospital gowns as a vehicle for bacterial dissemination in an intensive care unit.

The microbiota from the uniforms of 31 professionals from the general intensive care unit was analyzed. The samples were collected in duplicate at the beginning and at the end of the work period. Total viable counts of microorganisms were determined; there was a significant increase in the counts at the end of the period, when compared with those obtained at the beginning. No significant difference was observed between the first and second counts obtained from the cuffs. However, differences were observed for the samples from the abdominal region. Among the isolated pathogens 11/18 were Staphylococcus aureus, 2/18 were Acinetobacter baumannii, 2/18 were Klebsiela pneumoniae and 1/18 were Serratia rubidae. Some of these isolates were multi-resistant to antibiotics. Emphasis should be placed on reducing the spread of these pathogens in the hospital, making sure that biosafety protocols are followed by the staff.

Anti-Bacterial Agents↗

Synergistic activities of macrolide antibiotics against Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia, and Alcaligenes xylosoxidans isolated from patients with cystic fibrosis.

Azithromycin and clarithromycin were paired with other antibiotics to test synergistic activity against 300 multidrug-resistant pathogens isolated from cystic fibrosis (CF) patients. Clarithromycin-tobramycin was most active against Pseudomonas aeruginosa and inhibited 58% of strains. Azithromycin-trimethoprim-sulfamethoxazole, azithromycin-ceftazidime, and azithromycin-doxycycline or azithromycin-trimethoprim-sulfamethoxazole inhibited 40, 20, and 22% of Stenotrophomonas maltophilia, Burkholderia cepacia complex, and Achromobacter (Alcaligenes) xylosoxidans strains, respectively.

Alcaligenes↗

Five years of cefotaxime use in a neonatal intensive care unit.

In 1983 our antibiotic regimen for suspected neonatal septicemia was changed from amoxicillin-gentamicin to cefotaxime-amoxicillin. During the subsequent 5-year period we studied the effect of this change in regimen on the bacterial flora of the infants in the unit and the occurrence of serious infections. This was done with bacteriologic surveillance and analysis of the positive blood cultures from 1978 through 1987. A change in the relative numbers of isolated pathogens was observed; Klebsiella sp. and Escherichia coli decreased whereas Enterobacter sp. increased. The susceptibility of the Enterobacter isolates to cefamandole decreased from 85.3% in 1982 to 52.9% in 1983. The susceptibility of these bacteria to cefotaxime was 55.2% in 1983 and 55.0% in 1987. No change in susceptibilities to cefotaxime, amoxicillin or gentamicin was found in other pathogens. Although colonization with Enterobacter strains has increased and the susceptibility of these bacteria to the cephalosporins has decreased, the incidence of serious infections with Gram-negative bacteria decreased.

Amoxicillin↗

An Alcaligenes faecalis isolate from turkeys: pathogenicity in selected avian and mammalian species.

An Alcaligenes faecalis isolate of known pathogenicity for turkeys was examined for adherence and cytotoxicity in tracheal organ cultures of turkeys, chickens, Japanese quail, guinea pigs, hamsters, and mice, and for colonization and pathogenicity in these 6 species. Adherence and colonization were detected by fluorescent antibody staining. Infected and noninfected tracheal rings were examined by phase-contrast microscopy for cytotoxicity (ciliostasis, blebing of the cell membrane, and sloughing of the ciliated epithelium). Alcaligenes faecalis adhered to the tracheal rings of all species examined. Cytotoxicity was apparent in the tracheal rings of turkeys, quail, and chickens. Cytotoxicity was not detected in tracheal rings from the mammalian species. Alcaligenes faecalis colonization of turbinates and tracheas of intact turkeys and quail was detected. Clinical signs of alcaligenes rhinotracheitis were observed and histopathologic characteristics of the disease were detected. Chickens, guinea pigs, hamsters, and mice were refractory to infection with this isolate of A faecalis.

Adhesiveness↗

CANCER resistance surveillance program: initial results from hematology-oncology centers in North America. Chemotherapy Alliance for Neutropenics and the Control of Emerging Resistance.

OBJECTIVE: The CANCER (Chemotherapy Alliance for Neutropenics and the Control of Emerging Resistance) surveillance program was initiated to collect culture data on antimicrobial and antifungal agents in hospitals treating neutropenic patients in North America, as a means to monitor the development of microbial resistance. METHODS: A total of 2042 isolates from bloodstream, respiratory, urinary, and cutaneous infections in 2000-2001 were submitted by 33 oncology centers, clinics, and hospitals in North America, sent to a central laboratory, and tested by National Committee for Clinical Laboratory Standards methods against 42 different antimicrobials. RESULTS: Staphylococcus aureus, Escherichia coli, coagulase-negative staphylococci, Enterococcus spp., and Klebsiella spp. represented the most frequently isolated pathogens during the initial benchmark year. The incidence of extended-spectrum beta-lactamase-producing phenotypes ranged from 1.6% to 4.6% among E. coli and Klebsiella spp. Amikacin, tobramycin, polymyxin B, and piperacillin/tazobactam provided the highest susceptibility rates against Pseudomonas aeruginosa isolates. Yeast bloodstream isolates demonstrated complete susceptibility to amphotericin B, but 14% of strains were considered to have high-level fluconazole resistance. CONCLUSIONS: Elevated resistance rates when compared to general hospital strains were not observed in the CANCER program during the baseline year of this novel longitudinal, resistance surveillance program. The prevalence of gram-positive pathogens, although representing more than 50% of all bacterial isolates, was slightly lower than that reported previously by other investigators. Continued evaluation for antimicrobial resistance as well as changes in the prevalence of gram-positive pathogens requires the use of longitudinal surveillance programs such as the CANCER program. Such initiatives allow the development of therapeutic strategies for coping with changes in resistance and pathogen prevalence in this dynamic at-risk patient environment.

Anti-Bacterial Agents↗

[Experimental Mycoplasma bovis infection of the respiratory tract of calves].

Multiple intranasal experimental Mycoplasma (M.) bovis infection was induced to 22 calves and resulted in clinical manifestations. M. bovis was re-isolated from 17 of 24 lungs which had been altered by pneumonia. Pasteurella haemolytica was the only pathogen isolated from the pathologically affected lung of one of the experimental animals. The haematogenic proliferation phase was successfully identified in 5 of 8 examined calves. Arthritis was not recordable from any of the experimental animals. Interstitial and catarrhal to catarrhal-purulent bronchopneumonias were the most common histological findings. Peribronchial lymphoid cell accumulations occurred frequently, as time passed from onset of infection. Antibodies against M. bovis were detected in blood serum of infected animals by means of film inhibition, as of the 3. week from infection, and by means of indirect haemagglutination, as of the 4. week from infection.

Animals↗

[Isolation and identification of Streptococcus suis serotype 2 from sick-pig samples of Sichuan province].

Streptococcus suis serotype 2 (SS2) is a major pathogen frequently associated with infections in pigs. There are presently 35 serotypes of S.suis (serotype 1 to 34 and serotype 1/2) recognized on the basis of capsular antigens. Few people were reported to infect with SS2 in the past years. However, an accidental case happened in Sichuan province of China in 2005. Some people got ill and died, and all of them were closely contacted with sick pigs. Based on clinical features and epidemiologic data, this case could be caused by SS2 infection. Liver, spleen, kidney, lung and serum samples were collected and used for pathogen isolation and identification in laboratory, three strain bacteria were isolated. The three strains of SS2 showed typical morphology of SS2 on blood agar and under microscope with Gram stain. They were also agglutinated with standard serum of SS2. Biochemical characteristics of the three bacteria were tested using API 20 strep and analyzed by API software (version 3.3), results showed they were SS2. Four pairs of primer were designed, which were exactly matched the extracellular factor gene, muraminidase released protein gene, capsular polysaccharides gene and 16S rRNA gene respectively. These primers were used on polymerase chain reaction (PCR), and the PCR products were 626bp, 885bp, 487bp and 297bp on agarose gel, respectively. Drug sensitivity test were also done and results showed that they were sensitive to cefazolin, clindamycin, erythromycin, levofloxacin, nitrofurantoin, penicillin-G, and vancomycin and resistive to tetracycline. Balb/c mice infected with the isolated SS2 strain showed swelling in stomach and intestine, cyanochroia at mouth and suggillation under skin, which were similar to the clinical features of patients. Streptococcus suis serotype 2 were also found on lung sheeting sample under microscope with Gram stain. Rabbits infected with the isolated SS2 showed the similar clinical features with mice.

Animals↗