Clinical Features Fail to Distinguish Respiratory Infections Caused by<i>Branhamella catarrhalis</i>from Those Caused by<i>Haemophilus Influenzae</i>

Branhamella catarrhalisis being isolated with increasing frequency from patients with symptoms and signs of respiratory tract infection. Records of 77 patients were reviewed to define the spectrum of respiratory illness and to compare clinical and laboratory features with those of respiratory infection due toHaemophilus influenzae.BothB catarrhalisandH influenzaecaused respiratory infection predominantly in elderly males with underlying heart or lung disease. There were no clinical or laboratory features aside from sputum Gram stain and culture which differentiated the two groups. Although fewer than one-half of each group received antibiotics, no patient developed progressive respiratory disease.</jats:p

A Vignette-Based Survey to Assess Clinical Decision Making Regarding Antibiotic Use and Hospitalization of Patients with Probable Aseptic Meningitis

BACKGROUND: The many etiologies of meningitis influence disease severity – most viral causes are self-limiting, while bacterial etiologies require antibiotics and hospitalization. Aided by laboratory findings, the physician judges whether to admit and empirically treat the patient (presuming a bacterial cause), or to treat supportively as if it were viral.OBJECTIVE: To determine factors that lead infectious disease specialists to admit and treat in cases of suspected meningitis.METHODS: A clinical vignette describing a typical case of viral meningitis in the emergency department was presented to clinicians. They were asked to indicate on a Likert scale the likelihood of administering empirical antibiotics and admitting the patient from the vignette and for eight subsequent scenarios (with varied case features). The process was repeated in the context of an inpatient following initial observation and/or treatment.RESULTS: Participants were unlikely to admit or to administer antibiotics in the baseline scenario, but a low Glasgow Coma Score or a high cerebrospinal fluid (CSF) white blood cell count with a high neutrophil percentage led to empirical treatment and admission. These factors were less influential after a negative bacterial CSF culture. These same clinical variables led to maintaining treatment and hospitalization of the inpatient.CONCLUSIONS: Most participants chose not to admit or treat the patient in the baseline vignette. Confusion and CSF white blood cell count (and neutrophil predominance) were the main influences in determining treatment and hospitalization. A large range of response scores was likely due to differing regional practices or to different levels of experience.</jats:p

Cephamycin Resistance in Clinical Isolates and Laboratory-derived Strains of Escherichia coli, Nova Scotia, Canada

AmpC β-lactamase, altered porins, or both are usually responsible for cefoxitin resistance in Escherichia coli. We examined the relative importance of each. We studied 18 strains of clinical isolates with reduced cefoxitin susceptibility and 10 initially-susceptible strains passaged through cefoxitin-gradient plates. Of 18 wild-resistant strains, 9 had identical promoter mutations (including creation of a consensus 17-bp spacer) and related pulsed-field gel electrophoresis patterns; the other 9 strains were unrelated. Nine strains had attenuator mutations; two strains did not express OmpC or OmpF. After serial passage, 8 of 10 strains developed cefoxitin resistance, none developed promoter or attenuator mutations, 6 lost both the OmpC and OmpF porin proteins, and 1 showed decreased production of both. One strain had neither porin alteration or increased AmpC production. Porin mutants may occur more commonly and be less fit and less inclined to spread or cause disease than strains with increased β-lactamase expression

The Rapid Emergence of High Level Gentamicin Resistance in Enterococci

The proportion of enterococci isolated from blood and urine cultures that were highly resistant to gentamicin and streptomycin were determined. No blood or urine isolates highly resistant to gentamicin were seen in 1983, whereas by 1986–87 25% of blood and 17% of urine isolates were highly resistant. The rapid emergence of gentamicin resistance has serious implications for patients with life threatening enterococcal disease.Peer Reviewe

Clinical effectiveness of rapid tests for methicillin resistant Staphylococcus aureus (MRSA) in hospitalized patients: a systematic review

<p>Abstract</p> <p>Background</p> <p>Methicillin resistant <it>Staphylococcus aureus </it>(MRSA) are often resistant to multiple classes of antibiotics. The research objectives of this systematic review were to evaluate the clinical effectiveness of polymerase chain reaction (PCR) versus chromogenic agar for MRSA screening, and PCR versus no screening for several clinical outcomes, including MRSA colonization and infection rates.</p> <p>Methods</p> <p>An electronic literature search was conducted on studies evaluating polymerase chain reaction techniques and methicillin (also spelled meticillin) resistant <it>Staphylococcus aureus </it>that were published from 1993 onwards using Medline, Medline In-Process & Other Non-Indexed Citations, BIOSIS Previews, and EMBASE. Due to the presence of heterogeneity in the selected studies, the clinical findings of individual studies were described.</p> <p>Results</p> <p>Nine studies that compared screening for MRSA using PCR versus screening using chromogenic agar in a hospital setting, and two studies that compared screening using PCR with no or targeted screening were identified. Some studies found lower MRSA colonization and acquisition, infection, and transmission rates in screening with PCR versus screening with chromogenic agar, and the turnaround time for screening test results was lower for PCR. One study reported a lower number of unnecessary isolation days with screening using PCR versus screening with chromogenic agar, but the proportion of patients isolated was similar between both groups. The turnaround time for test results and number of isolation days were lower for PCR versus chromogenic agar for MRSA screening.</p> <p>Conclusions</p> <p>The use of PCR for MRSA screening demonstrated a lower turnaround time and number of isolation days compared with chromogenic agar. Given the mixed quality and number of studies (11 studies), gaps remain in the published literature and the evidence remains insufficient. In addition to screening, factors such as the number of contacts between healthcare workers and patients, number of patients attended by one healthcare worker per day, probability of colonization among healthcare workers, and MRSA status of hospital shared equipment and hospital environment must be considered to control the transmission of MRSA in a hospital setting.</p

Extended-Spectrum Beta-Lactamases

The definition of extended-spectrum beta-lactamases (ESBLs) has expanded rapidly, in terms of both the number and the variety of enzymes. Bacteria bearing plasmidic ESBLs are spreading widely throughout the world. In Canada, the problem has grown less rapidly than in other parts of the world; however, ESBLs still present a significant impediment to the treatment of serious infections with extendedspectrum cephalosporins and penicillins. Although SHV-derived enzymes were the primary concern in the late 1980s and early 1990s, these enzymes have been rapidly overtaken by the CTX-M family of ESBLs. There is no reason to believe that the problem of ESBLs will not expand rapidly in the face of intense antimicrobial pressure and lapses in infection control practices. Control should focus on early detection, accurate characterization, effective treatment and measures to prevent further spread

An Evaluation of Extended Incubation Time with Blind Subculture of Blood Cultures in Patients with Suspect Endocarditis

BACKGROUND: In a small proportion of patients, bacterial endocarditis is due to organisms that grow slowly and may not be recovered in conventional blood cultures incubated for five days. This has led to recommendations for prolonged incubation and routine subculture of negative cultures