Comparative epidemiology of gentamicin-resistant enterobacteria: persistence of carriage and infection

Gentamicin- and Ciprofloxacin-Resistant Enterobacteriaceae in Cattle Farms in Israel: Risk Factors for Carriage and the Effect of Microbiological Methodology on the Measured Prevalence

Our objectives were to establish a methodology for surveillance of ciprofloxacin-resistant Enterobacteriaceae and gentamicin-resistant Enterobacteriaceae (CPRE and GNRE, respectively) in cattle and to study the prevalence and risk factors for carriage of these bacteria in a national survey. This was a point prevalence study conducted from July to October 2013 in Israel. Stool samples were collected from 1,226 cows in 123 sections of 40 farms of all production types. The number of CPRE- and GNRE-positive cows was highest in quarantine stations and fattening farms and was lowest in pasture farms (p < 0.01). The number of CPRE- and GNRE-positive cows was lowest in dairy farm sections containing adult cows (>25 months) and highest in calves (<4 months) (p < 0.001). In bivariate analysis, other variables that were significant risk factors for CPRE and GNRE carriage included fewer troughs, crowding, lack of manure cleaning, and recent arrival of new calves. Antimicrobial prophylaxis was given almost exclusively to calves and was associated with a higher prevalence of carriers (p < 0.001). Compared to the use of nonselective media (MacConkey agar alone), the use of selective media (MacConkey agar with 10 μg/ml of ciprofloxacin or 5 μg/ml of gentamicin) increased the sensitivity of screening for CPRE and GNRE by 6.6- and 13.5-fold, respectively. CPRE and GNRE were identified in 609 (49.7%) and 840 (68.5%) samples, respectively. This study provides novel data regarding both the epidemiology of CPRE and GNRE carriage in livestock and the microbiological methodology for their surveillance.

HIGH PREVALENCE OF MULTI-DRUG RESISTANT KLEBSIELLA PNEUMONIAE IN A TERTIARY TEACHING HOSPITAL IN WESTERN KENYA

INTRODUCTION

Klebsiella pneumoniae is a gram negative enterobacteriaciae commonly associated with nosocomial infections. Multidrug resistant strains are increasingly being reported with corresponding increase in morbidity and mortality. The study outlines the epidemiology and antibiotic resistance pattern of K. pneumonia over a 10 year period in Moi Teaching and Referral Hospital, Eldoret, Kenya.

METHODOLOGY AND STUDY DESIGN

This is a retrospective analysis of all the blood culture results for K. pneumoniae isolates in the hospital for the period 2002-2013.

RESULTS

K. pneumoniae accounted for 23% of the hospital isolates (231/1356) during the study period; of these, 82.6% were from the New Born Unit. Most of the isolates were multi drug resistant with highest resistance of over 80% to Penicillins, Cephalosporins, Macrolides, Tetracyclines, Sulphonamides, Lincosamides and Chloramphenicol. Aminoglycoside and Quinolone resistance was also high at 49.2% and 41.3% respectively. The lowest resistance rates were documented for Carbapenems (23.2%). For specific antibiotics, there was high resistance to commonly used antibiotics (over 80% for Ceftriaxone, Cefipime, Gentamycin and Ceftazidime). The antibiotics with least resistance were Amikacin and Meropenem (21% and 7 % respectively).

CONCLUSION

There was a high prevalence of multidrug resistant K. pneumoniae isolates in the hospital, the majority originated from the New Born Unit. Resistance to third generation Cephalosporins and Gentamycin was high while Meropenem and Amikacin had the least resistance.

Molecular analysis of multiple-resistance plasmids transferred from gram-negative bacteria isolated in a urological unit

Forty-one isolates of multiply resistant gram-negative bacteria causing infection in a urological unit of a Dublin hospital were collected during a 6-month period. Twenty-one isolates transferred multiple resistance to an Escherichia coli K-12 recipient in liquid matings. Serratia marcescens, Proteus morganii, Proteus vulgaris, and E. coli isolates harbored similar 120-megadalton IncC plasmids, whereas Enterobacter cloacae strains transferred a 160-megadalton plasmid of a different Inc group. Southern hybridization experiments were performed with purified fragments cloned from one IncC plasmid as probes. They were hybridized to plasmid sequences in total cellular DNA extracts, showing that the IncC plasmids were very closely related. This suggests that the same plasmid has transferred to different bacterial species in the hospital environment.

Habitat association of Klebsiella species

The genus Klebsiella is seemingly ubiquitous in terms of its habitat associations. Klebsiella is a common opportunistic pathogen for humans and other animals, as well as being resident or transient flora (particularly in the gastrointestinal tract). Other habitats include sewage, drinking water, soils, surface waters, industrial effluents, and vegetation. Until recently, almost all these Klebsiella have been identified as one species, ie, K. pneumoniae. However, phenotypic and genotypic studies have shown that "K. pneumoniae" actually consists of at least four species, all with distinct characteristics and habitats. General habitat associations of Klebsiella species are as follows: K. pneumoniae--humans, animals, sewage, and polluted waters and soils; K. oxytoca--frequent association with most habitats; K. terrigena--unpolluted surface waters and soils, drinking water, and vegetation; K. planticola--sewage, polluted surface waters, soils, and vegetation; and K. ozaenae/K. rhinoscleromatis--infrequently detected (primarily with humans).