Philip M. Tierno

Outbreak of Klebsiella pneumoniae Producing a New Carbapenem-Hydrolyzing Class A β-Lactamase, KPC-3, in a New York Medical Center

ABSTRACT From April 2000 to April 2001, 24 patients in intensive care units at Tisch Hospital, New York, N.Y., were infected or colonized by carbapenem-resistant Klebsiella pneumoniae. Pulsed-field gel electrophoresis identified a predominant outbreak strain, but other resistant strains were also recovered. Three representatives of the outbreak strain from separate patients were studied in detail. All were resistant or had reduced susceptibility to imipenem, meropenem, ceftazidime, piperacillin-tazobactam, and gentamicin but remained fully susceptible to tetracycline. PCR amplified a blaKPC allele encoding a novel variant, KPC-3, with a His(272)→Tyr substitution not found in KPC-2; other carbapenemase genes were absent. In the outbreak strain, KPC-3 was encoded by a 75-kb plasmid, which was transferred in vitro by electroporation and conjugation. The isolates lacked the OmpK35 porin but expressed OmpK36, implying reduced permeability as a cofactor in resistance. This is the third KPC carbapenem-hydrolyzing β-lactamase variant to have been reported in members of the Enterobacteriaceae, with others reported from the East Coast of the United States. Although producers of these enzymes remain rare, the progress of this enzyme group merits monitoring.

Toxic shock syndrome in nasal surgery: A physiochemical and microbiologic evaluation of merocel® and nugauze® nasal packing†

A prospective comparison of the microbiologic safety of Merocel® versus NuGauze® nasal packing in 119 surgical patients is presented. Presurgical and postsurgical nasal cultures were obtained, analyzed, and compared. The importance of a preoperative nasal culture isolate of Toxic Shock Syndrome Toxin Number 1 (TSST‐1) producing Staphylococcus aureus in predicting postoperative toxigenic S. aureus isolation and Toxic Shock Syndrome symptomatology is demonstrated. An in vitro comparison of the ability of NuGauze® and Merocel® to amplify TSST‐1 production was performed.

Isolation of fungi by standard laboratory methods in patients with chronic rhinosinusitis.

Objectives/Hypothesis Allergic fungal sinusitis and the role of fungi in the pathogenesis of chronic rhinosinusitis are topics of interest and controversy in rhinology. The classification of chronic rhinosinusitis as either a bacterial infection or an allergic (eosinophilic) reaction to fungi has significant implications for treatment of this disease process. We designed a study to determine whether standard isolation techniques, as employed in a university hospital mycology laboratory, could isolate and identify fungi in the intraoperative specimens from patients undergoing functional endoscopic sinus surgery for chronic rhinosinusitis.

Staphylococcus aureus nasal carriage in patients with rhinosinusitis

Toxic shock syndrome has been associated with rhinologic surgery and medical devices, and it has been linked to a circulating exotoxin of a toxogenic strain of Staphylococcus aureus. One hundred forty patients with rhinosinusitis were studied. Nasal cultures were obtained. The microbiological characteristics are described. The carrier rate for Staphylococcus aureus was 35%. Thirty percent of patients selected for surgery were Staphylococcus aureus carriers. Toxin‐capable isolates were identified in 40% of those tested. Users of cocaine, topical decongestants, and steroid sprays had a statistically higher rate of Staphylococcus aureus carriage compared to non‐users. It is hoped that by identifying the population at risk and defining the factors associated with the development of toxic shock syndrome, a cogent policy of prevention can be established.

In vitro amplification of toxic shock syndrome toxin-1 by intravaginal devices

Super-absorbent tampons and an exotoxin of Staphylococcus aureus have been associated with the recent emergence of toxic shock syndrome (TSS). In the majority of cases, when a TSS strain of S. aureus was cultivated in the presence of various tampons and a contraceptive sponge, increased amounts of toxic shock syndrome toxin-1 (TSST-1) were observed to be produced into the blood medium by the bacterium. The amplification of toxin by these products adds support to the epidemiologic data in establishing the causal link between tampons and TSS.

Propensity of tampons and barrier contraceptives to amplify Staphylococcus aureusToxic shock syndrome toxin-I.

Objective: Although the incidence of reported cases of toxic shock syndrome (TSS) has declined in recent years, the disease continues to occur in menstruating women using the newer, less-absorbent tampons or barrier contraceptives. Extant tampons and other vaginal devices were tested for the ability to induce TSS toxin-1 (TSST-1) by a TSS strain of Staphylococcus aureus MN8, a known high-toxin producer. Tested for the first time were 20 varieties of tampons, including 2 all-cotton brands newly introduced in the United States, a polyurethane contraceptive sponge, a latex diaphragm, and a polymer menstrual collection cup. Methods: All products were washed in sterile distilled water prior to use to reduce the effect of leachable chemicals. Duplicate experiments with unwashed products were also performed. Entire tampons and other test products were immersed in brain heart infusion broth plus yeast extract (BHIY) and inoculated with S. aureus MN8, a known TSST-1 producer. After incubation, the culture supernatants were assayed for TSST-1 by gel immunodiffusion. Results: Except for all-cotton tampons, greater amounts of TSST-1 were detected in the supernatant fluid of washed tampons than detected in those which were not washed. While TSST-1 levels in unwashed non-cotton tampons ranged from 0.5 to 8 μg/ml, when these products were washed, TSST-1 levels increased to 2–32 μg/ml. In all-cotton tampons, whether washed or not, there was no detectable TSST-1. Conclusions: The propensity for all-cotton tampons not to amplify TSST-1 in vitro suggests they would lower the risk for tampon-associated TSS.

Increasing Antibiotic Resistance of Streptococcus Species in New York City

Objective: Streptococcus species are common pathogens in head and neck infections and are leading causes of morbidity and mortality. Emerging penicillin‐resistant streptococcal pathogens have shifted empirical antibiotic therapy in favor of valuable alternatives, including erythromycin and clindamycin. This study was undertaken to determine the magnitude of antimicrobial resistance to these antibiotics.

The survival of influenza A(H1N1)pdm09 virus on 4 household surfaces

We investigated the survival of a pandemic strain of influenza A H1N1 on a variety of common household surfaces where multiple samples were taken from 4 types of common household fomite at 7 time points. Results showed that influenza A H1N1sw virus particles remained infectious for 48 hours on a wooden surface, for 24 hours on stainless steel and plastic surfaces, and for 8 hours on a cloth surface, although virus recovery from the cloth may have been suboptimal. Our results suggest that pandemic influenza A H1N1 can survive on common household fomites for extended periods of time, and that good hand hygiene and regular disinfection of commonly touched surfaces should be practiced during the influenza season to help reduce transmission.

Nuclear, Chemical, and Biological Terrorism : Emergency Response and Public Protection

Introduction Purpose and Scope Historical Perspective on Terrorism Targeted against the US Historical Development of Nuclear Weapons Historical Development of Chemical Weapons Historical Development of Biological Weapons Conventional Explosives Available for Dispersing Agents General Types of Radiation and Warfare Agents Radiation Chemical Warfare Agents Biological Warfare Agents General Hazards from Exposure to Radiation and Warfare Agents Radiation Chemical Agents Biological Agents Minimizing Exposure to Radiation and Warfare Agents Time of Exposure Distance Shielding Responding to a Nuclear Explosion Nuclear Explosion Basics Response to Nuclear Explosion Preparing for a Nuclear, Chemical, or Biological Attack Emergency Preparedness Plan Emergency Preparedness Training Emergency Preparedness Practice Drills Alarm Systems Air Purification Systems Water Purification Systems Personal Protective Equipment First Aid Kits Communication Devices Emergency Lighting Emergency Food Supplies Screening Instruments Guidance for Emergency Responders Prioritizing Injuries Assessing Patients for Contamination Personnel Decontamination Procedures Exposure Guidance for Emergency Responders Training For Emergency Responders Summary of Recommendations Minimizing Exposure to Radiation (Dirty Bomb) and Warfare Agents Minimizing Exposure to Radiation from Nuclear Explosion Preparing for a Nuclear, Chemical, or Biological Attack Guidance for Emergency Responders

Proteolytic activity by multiple bacterial species isolated from chronic venous leg ulcers degrades matrix substrates.

Background: A major feature of chronic wounds is the loss of tissue, with the exposure of dermal components preventing primary closure and leading to bacterial colonization. Bacterial colonization has been proposed as one of the common underlying pathologies present in chronic wounds. The objective of this exploratory study was to identify bacteria cultured from chronic venous leg ulcers and test for proteolytic activity that degrades matrix substrates. Method: Bacteria were isolated, cultured, and identified from six subjects (average age = 62.8 years) over 2–10 months under an approved protocol using swabs and microbiological culture media. Proteolytic activity against (a) gelatin, (b) an elastin substrate, and (c) a serine/trypsin-sensitive substrate was determined using a colorimetric plate assay with an ELISA plate reader and zymography. Results: We identified 13 bacteria that expressed proteolytic activity against one or more of the tested substrates. Of these, six were Gram-positive (Staphylococcus aureus, Enterococcus faecalis, Staphylococcus epidermidis, Streptococcus agalactiae, Corynebacterium, and Streptococcus bovis) and seven were Gram-negative (Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Morganella morganii, Klebsiella pneumoniae, Bacteroides fragilis, and Serratia marcescens) organisms. Two of these, S. aureus and P. aeruginosa, are recognized wound pathogens. Conclusions: Multiple bacteria species isolated from colonized venous leg ulcers have the capacity to secrete proteases capable of degrading components of the extracellular matrix important for wound healing. Matrix degradation by bacteria may contribute to delays in tissue deposition and repair, suggesting that treatment of chronic wounds should include appropriate management of colonizing bacteria.