Foodborne illness among factory workers, Gweru, Zimbabwe, 2012: a retrospective cohort study

Identification of floR Variants Associated With a Novel Tn4371-Like Integrative and Conjugative Element in Clinical Pseudomonas aeruginosa Isolates

Florfenicol is widely used to control respiratory diseases and intestinal infections in food animals. However, there are increasing reports about florfenicol resistance of various clinical pathogens. floR is a key resistance gene that mediates resistance to florfenicol and could spread among different bacteria. Here, we investigated the prevalence of floR in 430 Pseudomonas aeruginosa isolates from human clinical samples and identified three types of floR genes (designated floR, floR-T1 and floR-T2) in these isolates, with floR-T1 the most prevalent (5.3%, 23/430). FloR-T2 was a novel floR variant identified in this study, and exhibited less identity with other FloR proteins than FloRv. Moreover, floR-T1 and floR-T2 identified in P. aeruginosa strain TL1285 were functionally active and located on multi-drug resistance region of a novel incomplete Tn4371-like integrative and conjugative elements (ICE) in the chromosome. The expression of the two floR variants could be induced by florfenicol or chloramphenicol. These results indicated that the two floR variants played an essential role in the host's resistance to amphenicol and the spreading of these floR variants might be related with the Tn4371 family ICE.

Low Consumption of Indigenous Fresh Dairy Products in Ghana Attributed to Poor Hygienic Quality

This cross-sectional study was aimed at assessing consumer perceptions and microbiological quality of the fresh cow's milk products available in selected dairying communities in Ghana. Twenty-six focus groups (FGs) were conducted to understand the perceptions on barriers and facilitators to dairy consumption. These included six FGs for lactating mothers and five FGs for each of the following categories: pregnant women, women of reproductive age with children younger than 5 years, not pregnant and nonlactating women, and males. A separate quantitative survey followed and included 176 women of reproductive age (18 to 49 years) and 90 males (18 to 59 years) from 15 dairying communities in the Greater Accra, Eastern, and Central regions of Ghana. Also, 120 locally sourced fresh milk products were assessed for counts of total coliforms, fecal coliforms, and Enterococcus spp., and presence of pathogenic Streptococcus spp. , Escherichia coli, and Klebsiella pneumoniae by using standard microbiological methods. Fecal coliforms in dairy products, such as brukina, wagashi, and yogurt exceeded the specified limit of 10 CFU/mL, while the prevalence of E. coli and K. pneumoniae were 70 and 65%, respectively. Generally, respondents perceived indigenous dairy as unsafe. These perceptions were formed on the basis of visual cues of environmental and personal hygiene. Of the indigenous milk products consumed, brukina, a fermented milk and millet gruel (33%) and wagashie, a soft unfermented cheese (29%), were the most popular. However, only 19% of wagashie and 21% of brukina consumers believed these products were safe. Consistently, the odds of consuming a particular milk product was significantly higher if the consumer believed it was safe. Poor sanitation and unhygienic processing of otherwise healthy but perishable indigenous milk products has justifiably fueled the mistrust of consumers and may hinder potential intervention efforts to increase milk production and consumption in Ghana.

Spread of the florfenicol resistance floR gene among clinical Klebsiella pneumoniae isolates in China

Background

Florfenicol is a derivative of chloramphenicol that is used only for the treatment of animal diseases. A key resistance gene for florfenicol, floR, can spread among bacteria of the same and different species or genera through horizontal gene transfer. To analyze the potential transmission of resistance genes between animal and human pathogens, we investigated floR in Klebsiella pneumoniae isolates from patient samples. floR in human pathogens may originate from animal pathogens and would reflect the risk to human health of using antimicrobial agents in animals.

Methods

PCR was used to identify floR-positive strains. The floR genes were cloned, and the minimum inhibitory concentrations (MICs) were determined to assess the relative resistance levels of the genes and strains. Sequencing and comparative genomics methods were used to analyze floR gene-related sequence structure as well as the molecular mechanism of resistance dissemination.

Results

Of the strains evaluated, 20.42% (67/328) were resistant to florfenicol, and 86.96% (20/23) of the floR-positive strains demonstrated high resistance to florfenicol with MICs ≥512 μg/mL. Conjugation experiments showed that transferrable plasmids carried the floR gene in three isolates. Sequencing analysis of a plasmid approximately 125 kb in size (pKP18-125) indicated that the floR gene was flanked by multiple copies of mobile genetic elements. Comparative genomics analysis of a 9-kb transposon-like fragment of pKP18-125 showed that an approximately 2-kb sequence encoding lysR-floR-virD2 was conserved in the majority (79.01%, 83/105) of floR sequences collected from NCBI nucleotide database. Interestingly, the most similar sequence was a 7-kb fragment of plasmid pEC012 from an Escherichia coli strain isolated from a chicken.

Conclusions

Identified on a transferable plasmid in the human pathogen K. pneumoniae, the floR gene may be disseminated through horizontal gene transfer from animal pathogens. Studies on the molecular mechanism of resistance gene dissemination in different bacterial species of animal origin could provide useful information for preventing or controlling the spread of resistance between animal and human pathogens.

Recent Research Examining Links Among Klebsiella pneumoniae from Food, Food Animals, and Human Extraintestinal Infections

Klebsiella pneumoniae is a colonizer of livestock, a contaminant of retail meats and vegetables, and a cause of extraintestinal infections in humans. Antibiotic-resistant strains of K. pneumoniae are becoming increasingly prevalent among hospital and community-acquired infections. Antibiotics are used extensively in conventional food-animal production, where they select for antibiotic-resistant bacteria. Antibiotic-resistant K. pneumoniae has been isolated from livestock as well as from a variety of retail meats, seafood, and vegetables. Furthermore, recent phylogenetic analyses suggest close relationships between K. pneumoniae from humans and livestock. Therefore, it is essential that we quantify the contribution of foodborne K. pneumoniae to antibiotic-resistant human infections.