Shewanella algae is a rod-shaped Gram-negative marine bacterium frequently found in nonhuman sources such as aquatic ecosystems and has been shown to be the pathogenic agent in various clinical cases due to the ingestion of raw seafood. The results of this study showed that S. algae was present in approximately one in four samples, including water and shellfish samples. Positive reactions (API systems) in S. algae strains were seen for gelatinase (gelatin); however, negative reactions were found for indole production (tryptophan). S. algae is adapted to a wide range of temperatures (4°C, 25°C, 37°C, and 42°C) and salinity. Temperature is a key parameter in the pathogenicity of S. algae as it appears to induce hemolysis at 25°C and 37°C. S. algae exhibits pathogenic characteristics at widely varying temperatures, which suggests that it may have the ability to adapt to climate change.

Recent studies have focused on foodborne or commensal bacteria as vehicles of antibiotic resistance. However, the antibiotic resistance of milk bacteria from healthy donors is still vague in Taiwan. For this purpose, human milk samples were obtained from randomly recruited 19 healthy women between 3 and 360 days post-partum. Antibiotic susceptibility profile of bacteria from milk samples was determined. About 20 bacterial species were isolated from milk samples including Staphylococcus (6 species), Streptococcus (4 species), Enterococcus (2 species), Lactobacillus (1 species), and bacteria belonging to other genera (7 species). Some opportunistic or potentially pathogenic bacteria including Kluyvera ascorbata, Klebsiella oxytoca, Klebsiella pneumoniae, Acinetobacter baumannii, Actinomyces bovis, and Staphylococcus aureus were also isolated. Intriguingly, Staphylococcus isolates (22 strains) were resistant to 2–8 of 8 antibiotics, while Streptococcus isolates (3 strains) were resistant to 3–7 of 9 antibiotics, and members of the genus Enterococcus (5 strains) were resistant to 3–8 of 9 antibiotics. Notably, Staphylococcus lugdunensis, S. aureus, Streptococcus parasanguinis, Streptococcus pneumonia, and Enterococcus faecalis were resistant to vancomycin, which is considered as the last-resort antibiotic. Therefore, this study shows that most bacterial strains in human milk demonstrate mild to strong antibiotic resistance. Whether commensal bacteria in milk could serve as vehicles of antibiotic resistance should be further investigated.

Recent reports have shown that food-borne or commensal bacteria can function as reservoirs of antibiotic resistance. However, the antibiotic susceptibility of bacterial isolates of most milk samples or the total bacterial counts (TBC) in human milk from healthy donors, are not fully understood in Taiwan. Thus, five healthy mothers were randomly recruited each month, and totally 30 mothers without any symptoms of infection were recruited over 6 months. Milk samples were then harvested and analyzed immediately after collection. The antibiotic susceptibility was analyzed in bacteria isolated from milk samples using nine clinically relevant antibiotics, such as oxacillin, ampicillin, cephalothin, amoxicillin, ciprofloxacin, erythromycin, clindamycin, gentamicin, and oxytetracycline. The Staphylococcus strains (48 isolates) found in milk resisted to 48.6 ± 20.1% selected antibiotics. Streptococcus-related isolates (8 isolates) exhibited resistance to 41.7 ± 26.4% selected antibiotics. Acinetobacter isolates (5 isolates) were resistant to 66.7 ± 13.6% antibiotics, and Enterococcus isolates (5 isolates) were resistant to 73.3 ± 6.1% tested antibiotics. Rothia-related isolates (4 isolates) were resisted to 58.2 ± 31.9% of tested antibiotics. In contrast, Corynebacterium isolates (5 isolates) were sensitive to 66%-100% of selected antibiotics. Furthermore, the TBC ranged from 40 to 710,000 CFU/ml, implying a wide spectrum of bacteria in milk from healthy mothers. Despite this, all milk donors were healthy during sampling, and they did not show any symptoms related to mastitis or subclinical mastitis. According to the previously described TBC criteria for the use of donated human milk, only 73% of the current milk samples could be accepted for the milk bank. In conclusion, the majority of the isolated bacterial strains from current human milk samples are multiresistant strains. In milk samples for preterm infants or milk banks, higher TBC levels or potentially antibiotic-resistant bacteria in some milk samples have supported people using approaches to disinfect human milk partially.

BackgroundShewanella algae has been recognized as an emerging human pathogen. However, not much is known about the mechanism of its pathogenesis and its adaptation to a special niche such as the hepatobiliary tract.ResultsIn this study, we isolated the S. algae ACCC strain from human bile and performed whole genome sequencing. S. algae ACCC consists of a circular 4,743,354-bp chromosome with a GC content of 53.08%, within 4080 protein coding sequences. The genome of strain ACCC contains a number of candidate genes which have been reported to be associated with bile adaption, including htpB, exbBD, wecA, galU, adeFGH and phoPQ regulon.ConclusionsOur results highlight the association of S. algae with a rare disease profile. Further studies are needed to shed light on the evolution of pathogenesis and the niche adaptation of S. algae.Electronic supplementary materialThe online version of this article (10.1186/s13099-018-0267-4) contains supplementary material, which is available to authorized users.

This study included fifty-eight isolates of P. aeruginosa from the oral cavity of snakes that were recruited from clinical cases, captive and wild snakes. The minimum inhibitory concentrations (MICs) for the determination of susceptibility were identified by the broth microdilution method. Polymerase chain reaction (PCR) was employed to detect β-lactamases genes. With regard to antipseudomonal antibiotics, the lowest nonsusceptible rates were in aztreonam (15%), piperacillin/tazobactam (12%), and amikacin (9%). The nonsusceptible rates were high in gentamicin (33%) and colistin (55%). Meanwhile, blaTEM presented in 100% of isolates where blaAmpC, blaOXA-1, and blaOXA-10 came at 94.8%, 89.7%, and 27.6%, respectively. Emergence of multidrug resistant (MDR) strains and colistin-resistant strains highlights the potential breach of public health as P. aeruginosa could be transmitted through either direct contact or indirect dissemination through the environment. This study reports that the highly resistant P. aeruginosa from snakes' oral cavity were discovered for the very first time in Taiwan.