Colin Block

Cluster of Neonatal Infections in Jerusalem due to Unusual Biochemical Variant of Enterobacter sakazakii

Abstract.Reported here is a cluster of infections due to a nitrate-negative variant of Enterobacter sakazakii, which occurred among premature neonates at the Hadassah Hospital, Mount Scopus, Jerusalem, in December 1999–January 2000. Pulsed-field gel electrophoresis showed cluster isolates to be identical but unrelated to previous systemic isolates recovered in 1993 and 1998. The organism was not isolated from infant formula powder, but it was recovered from prepared formula and from a kitchen blender. Elimination of the environmental focus, a change to factory-prepared infant formula, and isolation of affected infants terminated the event. Faecal carriage of Enterobacter sakazakii was observed for up to 18 weeks, emphasising the potential for cross-infection.

Multidrug-resistant Trichosporon asahii infection of nongranulocytopenic patients in three intensive care units.

ABSTRACT Trichosporon asahii (Trichosporon beigelii) infections are rare but have been associated with a wide spectrum of clinical manifestations, ranging from superficial involvement in immunocompetent individuals to severe systemic disease in immunocompromised patients. We report on the recent recovery ofT. asahii isolates with reduced susceptibility in vitro to amphotericin B (AMB), flucytosine, and azoles from six nongranulocytopenic patients who exhibited risk factors and who developed either superficial infections (four individuals) or invasive infections (two individuals) while in intensive care units. The latter two patients responded clinically and microbiologically to AMB treatment. All six isolates were closely related according to random amplified polymorphic DNA studies and showed 71% similarity by amplified fragment length polymorphism analysis, suggesting a common nosocomial origin. We also review the literature pertaining toT. asahii infections and discuss the salient characteristics of this fungus and recent taxonomic proposals for the genus.

Group G Streptococcal Bacteremia in Jerusalem

Recurrent group G Steptococcus bacteremia, associated with lymphatic disorders and possibly emm stG840.0, is described.

Antibiotic Exposure as a Risk Factor for Fluconazole-Resistant Candida Bloodstream Infection

ABSTRACT Recent exposure to azoles is an important risk factor for infection with fluconazole-resistant Candida spp., but little is known about the role of antibacterial drug exposure in the emergence of drug-resistant Candida. We did a prospective nationwide surveillance study of candidemia in Israel and analyzed the propensity score-adjusted association between antifungal and antibacterial drug exposure and bloodstream infection with C. glabrata and fluconazole-resistant Candida isolates. Four hundred forty-four episodes of candidemia (450 Candida isolates, 69 [15%] C. glabrata isolates, and 38 [8.5%] fluconazole-resistant isolates) from 18 medical centers in Israel were included. C. glabrata bloodstream infection was strongly associated with recent metronidazole exposure (odds ratio [OR], 3.2; P < 0.001). Infection with a fluconazole-resistant isolate was associated with exposure to carbapenems, trimethoprim-sulfamethoxazole, clindamycin, and colistin (odds ratio, 2.8; P = 0.01). The inclusion of antibacterial drug exposure in a multivariable model significantly enhanced the models predictive accuracy for fluconazole-resistant Candida bloodstream infection. Our findings may be relevant to the selection of empirical antifungal treatment and broaden the scope of antibiotic-associated collateral damage.

Interlaboratory comparison of agar dilution and etest methods for determining the MICs of antibiotics used in management of Neisseria meningitidis infections

ABSTRACT Previous studies have shown that there is considerable variation in the methods and media used to determine the susceptibility of Neisseria meningitidis to antimicrobial agents in different countries. In this study, national and regional reference laboratories used a standardized methodology to determine the MICs of antibiotics used in the management of meningococcal infection. Fourteen laboratories participated in the study, determining the susceptibility to penicillin G, rifampin, cefotaxime, ceftriaxone, ciprofloxacin, and ofloxacin of a collection of 17 meningococci, of which 11 strains were previously defined as having intermediate resistance to penicillin (PenI) by sequencing and restriction fragment length polymorphism analysis of the penA gene. The MIC was determined by agar dilution and Etest with Mueller-Hinton agar (MH), MH supplemented with sheep blood (MH+B), and MH supplemented with heated (chocolated) blood. Several laboratories encountered problems obtaining confluent growth with unsupplemented MH. MH+B was considered to give the most congruent and reproducible results among the study laboratories. The modal MIC for MH+B for each antibiotic and method was calculated to define the MIC consensus, allowing assessment of each individual laboratorys data in relation to the others. The agreement in each antibiotic/method/medium combination was defined as the percentage of laboratories with a result within one dilution of the modal result. For the whole study, an agreement of 90.6% was observed between agar dilution and Etest methods. The agreement in each laboratory/antibiotic/method combination ranged from 98.2% to 69.7%, with six laboratories demonstrating agreement higher than 90% and 11 more than 80%. The ability of the laboratories to detect the PenI isolates ranged from 18.2% to 100%. The apparent difficulty in interpreting susceptibility to rifampin, particularly with the Etest method, is very interesting.

Identification of Risk Factors for Infection in an Outbreak of Mycoplasma pneumoniae Respiratory Tract Disease

BACKGROUND Mycoplasma pneumoniae is one of the most common pathogens that causes community-acquired respiratory tract infection. Outbreaks are well known, and all age groups are susceptible. An outbreak in an army training unit afforded an opportunity to identify possible risk factors for morbidity. METHODS An outbreak of respiratory illness that occurred in a unit comprising 91 trainees was investigated and analyzed as a cohort study. M. pneumoniae infection was suspected on clinical grounds and was confirmed by polymerase chain reaction, culture, and serologic testing. Data regarding medical history, symptoms, signs, and laboratory tests were collected. RESULTS During a period of 12 days, 41 soldiers (45.1%) had respiratory illnesses, of which 10 (11.0%) were pneumonia. Comparison of symptomatic and asymptomatic individuals revealed that smoking was associated with higher rates of disease (risk ratio, 2.1; 95% confidence interval [CI], 1.3-3.2; P<.005) and seroconversion (risk ratio, 2; 95% CI, 1.2-3.4; P=.03). In multivariate analysis, both lower acute immunoglobulin G values (adjusted odds ratio, 7.8; 95% CI, 1.4-42.5; P=.018) and smoking (adjusted odds ratio, 5.6; 95% CI, 1.5-20.4; P=.01) were associated with symptomatic infection; stratification according to smoking status revealed that immunoglobulin G levels among nonsmokers were protective. Patients who had pneumonia had lower lymphocyte counts (1400+/-258 vs. 2000+/-465 cells/microL; P=.001). CONCLUSIONS Smoking and lower preexisting immunoglobulin G levels were strongly associated with M. pneumoniae respiratory infection. These findings emphasize the importance of immunity and cessation of smoking for the prevention of disease. The high attack rate emphasizes the extent of infection transmission among healthy persons living in close contact.

Factors associated with nosocomial diarrhea and Clostridium difficile-associated disease on the adult wards of an urban tertiary care hospital.

Abstract A prospective survey of the adult inpatient population of an urban tertiary care hospital was conducted to determine factors associated with the development of nosocomial diarrhea and the acquisition of Clostridium difficile-associated disease. During the 3-month survey, 98 patients with nosocomial diarrhea were enrolled, and 38 controls were recruited. The controls were patients without diarrhea lying in beds adjacent to the affected patients. Factors significantly associated with nosocomial diarrhea were the administration of a special diet (P=0.02) and receipt of a greater number of different antibiotics (P=0.02). Among the 98 patients with diarrhea, Clostridium difficile toxin B was identified in the stool of 13. Factors found to be associated with the presence of toxin B as compared to other causes of nosocomial diarrhea were a greater number of individual antibiotics used during hospitalization (P=0.02) and receipt of a cephalosporin (P=0.03) or, more specifically, a third-generation cephalosporin (P=0.02). Among patients with nosocomial diarrhea, those who had toxin in their stool had a significantly higher total antibiotic burden (expressed as antibiotic days) than those with diarrhea due to other causes (P=0.01).

Vancomycin-resistant enterococci in long-term care facilities.

Knowledge of the prevalence rates and associated risk markers of vancomycin-resistant enterococci (VRE) colonization among long-term care facility (LTCF) residents could be used to improve screening policies among newly admitted hospital inpatients. In a cross-sectional survey among 1,215 residents of LTCFs in Jerusalem, the VRE carriage rate was 9.6%. Previous hospitalization and antibiotic treatment were associated with elevated VRE colonization rate. In contrast, moderate and severe levels of dependency and prolonged stay in an LTCF were associated with a decrease in the VRE colonization rate.

Changes in qnr Prevalence and Fluoroquinolone Resistance in Clinical Isolates of Klebsiella pneumoniae and Enterobacter spp. Collected from 1990 to 2005

ABSTRACT Clinical isolates of Klebsiella pneumoniae and Enterobacter spp. collected from 1990 through 2005 at a tertiary care center were studied for qnr genes. Isolates bearing these genes emerged in the mid-1990s, coinciding with the time of a rapid increase in fluoroquinolone resistance. Sixty percent of these isolates were ciprofloxacin susceptible by CLSI breakpoints.

Institutional Control Measures to Curtail the Epidemic Spread of Carbapenem-Resistant Klebsiella pneumoniae: A 4-Year Perspective

OBJECTIVE To describe the implementation of an institution-wide, multiple-step intervention to curtail the epidemic spread of carbapenem-resistant Klebsiella pneumoniae (CRKP). DESIGN Consecutive intervention analyses. PATIENTS AND SETTING All patients admitted to a 775-bed tertiary care medical center in Jerusalem, Israel, from 2006 through 2010. INTERVENTIONS The effects of 4 interventions were assessed: (1) a policy of isolation for patients colonized or infected with CRKP in single rooms, which was started in March 2006; (2) cohorting of CRKP patients with dedicated nursing staff and screening of patients neighboring a patient newly identified as a carrier of CRKP, which was started in March 2007; (3) weekly active surveillance of intensive care unit patients, which was started during August 2008; and (4) selective surveillance of patients admitted to the emergency department, which was started in March 2009. Interrupted regression analysis and change-point analysis were used to assess the effect of each intervention on the CRKP epidemic. RESULTS Patient isolation alone failed to control the spread of CRKP, with incidence increasing to a peak of 30 new cases per 1,000 hospital beds per month. Institution of patient cohorting led to a steep decline in the incidence of CRKP acquisition (P < .001). Introduction of active surveillance interventions was followed by a decrease in the incidence of CRKP-positive clinical cultures but an increase in the incidence of CRKP-positive screening cultures. The mean prevalence of CRKP positivity for the period after cohorting began showed a statistically significant change from the mean prevalence in the preceding period (P < .001). CONCLUSIONS The cohorting of patients with dedicated staff, combined with implementation of focused active surveillance, effectively terminated the epidemic spread of CRKP. Cohorting reduced cross-infection within the hospital, and active surveillance allowed for earlier detection of carrier status. Both interventions should be considered in attempts to contain a hospital epidemic.