A Case of Rahnella aquatilis Bacteraemia After the Receipt of an Unlicensed Intravenous Vitamin Infusion, the First to be Reported in the UK

Patient: Male, 37-year-oldFinal Diagnosis: Septic shockSymptoms: Fever • rigorsMedication: —Clinical Procedure: —Specialty: Infectious DiseasesObjective:Rare diseaseBackground:Rahnella aquatilis is a facultatively anaerobic, gram-negative rod bacterium commonly found in freshwater. There are few cases of bacteremia caused by Rahnella aquatilis in the literature and even fewer cases reported of it causing sepsis in immunocompetent individuals. In this case report, we present a rare case of an immunocompetent individual who developed sepsis secondary to bacteremia caused by Rahnella aquatilis.Case Report:A 37-year-old immunocompetent man with cerebral palsy and chronic enterocutaneous fistulas, with an in-dwelling peripherally inserted central catheter (PICC) line for total parenteral nutrition (TPN), presented to the emergency department with complaints of increased enteric drainage from his fistula, rigors, and subjective fevers following a mechanical fall, which occurred approximately 1 week before. The day following admission, the patient developed septic shock and was transferred to the intensive care unit for vasopressor support. He was given intravenous cefepime and metronidazole for empiric therapy. Blood cultures grew Rahnella aquatilis, and antibiotic therapy was de-escalated to monotherapy with intravenous ceftriaxone. The patient’s condition stabilized, his PICC line was replaced, and he was successfully discharged, and continued on outpatient antibiotic therapy with ceftriaxone.Conclusions:This case report represents a novel presentation of septic shock secondary to bacteremia caused by a gram-negative rod bacterium, Rahnella aquatilis, in an immunocompetent host dependent on TPN via a PICC line. This case also demonstrates that Rahnella aquatilis can be susceptible to and treated successfully with intravenous ceftriaxone. Bacteremia caused by Rahnella aquatilis can cause a swift, aggressive decompensation and should be treated with antibiotics immediately.

Editorial Commentary: Genomic Epidemiology: Revealing Hidden Reservoirs for Klebsiella pneumoniae.

Rahnella aquatilis is a water-residing gram-negative rod, a member of the family Enterobacteriaceae, isolated rarely from clinical specimens of immunocompromised patients. A case of a surgical wound infection caused by R. aquatilis in a patient who underwent a prosthetic surgical intervention is reported. The presence of inducible beta-lactamase was suggested by the disk induction test and the conventional agar dilution assay. Literature on R. aquatilis infections in humans is reviewed.

65-Year-Old Man With Weight Loss and Dyspnea on Exertion

Asaia spp. has recently been reported to cause opportunistic infections in humans and is becoming an emerging hospital pathogen. To our knowledge, this is the first reportonAsaiaspp. in Malaysia. bacteremia in an infant. A girl with underlying Hirschsprung's disease, who was on parenteral feeding via a central venous catheter, developed persistent multidrug-resistant Gram-negative bacteremia. Routine automated identification methods failed to identify the organism, which was later identified by 16S ribosomal RNA sequencing. Bacterial clearance was achieved after the removal of the catheter and initiation of IV amikacin. This case highlights the role of molecular identification and the clinical importance of Asaia spp. in causing infections in humans, especially in patients with indwelling devices.

BackgroundAlcaligenes faecalis is usually causes opportunistic infections in humans. Alcaligenes faecalis infection is often difficult to treat due to its increased resistance to several antibiotics. The results from a clinical study of patients with Alcaligenes faecalis infection may help improve patients’ clinical care.MethodsWe conducted a retrospective analysis of all patients presenting with Alcaligenes faecalis infection from January 2014 to December 2019. The medical records of all patients were reviewed for demographic information, clinical symptoms and signs, comorbidities, use of intravenous antibiotics within the past three months, bacterial culture, antibiotics sensitivity test, and clinical outcomes.ResultsSixty-one cases of Alcaligenes faecalis infection were seen during the study period, including 25 cases of cystitis, nine cases of diabetic foot infection, eight cases of pneumonia, seven cases of acute pyelonephritis, three cases of bacteremia, and nine cases of infection at specific sites. Thirty-seven patients (60.7%) had a history of receiving intravenous antibiotics within three months of the diagnosis. Fifty-one (83.6%) cases were mixed with other bacterial infections. Extensively drug-resistant infections have been reported since 2018. The best sensitivity rate to Alcaligenes faecalis was 66.7% for three antibiotics (imipenem, meropenem, and ceftazidime) in 2019. Two antibiotics (ciprofloxacin and piperacillin/tazobactam) sensitivity rates to A. faecalis were less than 50%.ConclusionsThe most frequent Alcaligenes faecalis infection sites, in order, are the bloodstream, urinary tract, skin and soft tissue, and middle ear. The susceptibility rate of Alcaligenes faecalis to commonly used antibiotics is decreasing. Extensively drug-resistant Alcaligenes faecalis infections have emerged.

Meningitis caused by Streptococcus suis serotype 14, North America.

Hot spring water may harbour emerging waterborne opportunistic pathogens that can cause infections in humans. We have investigated the diversity and antimicrobial resistance of culturable emerging and opportunistic bacterial pathogens, in water and sediment of hot springs located in Limpopo, South Africa. Aerobic bacteria were cultured and identified using 16S ribosomal DNA (rDNA) gene sequencing. The presence of Legionella spp. was investigated using real-time polymerase chain reaction. Isolates were tested for resistance to ten antibiotics representing six different classes: β-lactam (carbenicillin), aminoglycosides (gentamycin, kanamycin, streptomycin), tetracycline, amphenicols (chloramphenicol, ceftriaxone), sulphonamides (co-trimoxazole) and quinolones (nalidixic acid, norfloxacin). Gram-positive Kocuria sp. and Arthrobacter sp. and gram-negative Cupriavidus sp., Ralstonia sp., Cronobacter sp., Tepidimonas sp., Hafnia sp. and Sphingomonas sp. were isolated, all recognised as emerging food-borne pathogens. Legionella spp. was not detected throughout the study. Isolates of Kocuria, Arthrobacter and Hafnia and an unknown species of the class Gammaproteobacteria were resistant to two antibiotics in different combinations of carbenicillin, ceftriaxone, nalidixic acid and chloramphenicol. Cronobacter sp. was sensitive to all ten antibiotics. This study suggests that hot springs are potential reservoirs for emerging opportunistic pathogens, including multiple antibiotic resistant strains, and highlights the presence of unknown populations of emerging and potential waterborne opportunistic pathogens in the environment.

The presence of Pseudomonas spp. in food poses a health concern due to their ability to grow during cold storage. Pseudomonas fluorescens and P. aeruginosa are two important species that cause food spoilage and foodborne illness, respectively. P. fluorescens is responsible for food spoilage due to secretion of protease and lipase enzymes, which cause off-odours, off-flavours, and rancidity, even under refrigeration storage. P. aeruginosa is recognised as opportunistic pathogens that causes illness in infected individuals. P. aeruginosa harbours multiple virulence factors that enable it to be a successful pathogen to cause infection in humans. Both of these bacteria commonly contaminate poultry products which cause quality and safety issues. They are capable of forming biofilm in food processing environments, and exhibit multiple antibiotic resistances. The biofilm formation enables these bacteria to persist in the environments, and contaminate food if improper sanitation and handling happen. The contaminated food will have a shorter shelf life which leads to food wastage. Pathogenic P. aeruginosa that exhibits multiple antibiotic resistance will cause serious foodborne illness to infected individuals due to failure in clinical treatment. As such, controlling the growth of these bacteria in poultry is important which can be done through good hygiene practices, modified air packaging, biopreservatives, and low temperature storage. Detection of these bacteria in poultry will also help to ensure the quality and safety related to poultry. Selective agar plating is an important method to isolate Pseudomonas spp., which is important for further analysis. Molecular methods such as polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) are pivotal for rapid, robust, and specific detection of the targeted bacteria.

Proteus

Rahnella aquatilis, a saprophytic organism, is a member of the Enterobacteriaceae family. The natural habitat of this organism is fresh water, and it is rarely found in clinical specimens. Clinical conditions ascribed to this organism include bacteremia, respiratory infection, urinary tract infection, wound infection in an immunocompromised host, and infective endocarditis in patients with congenital heart diseases. Here, we report a case of bacteremia due to R. aquatilis in a woman with breast cancer who had received chemotherapy through a chemoport. To our knowledge, this is the second case of bacteremia caused by this organism in a patient with cancer in Korea.

The putative bacterial oxygen sensor Pseudomonas prolyl hydroxylase (PPHD) suppresses antibiotic resistance and pathogenicity in Pseudomonas aeruginosa

BackgroundPseudomonas species are common on food, but their contribution to the antimicrobial resistance gene (ARG) burden within food or as a source of clinical infection is unknown. Pseudomonas aeruginosa is an opportunistic pathogen responsible for a wide range of infections and is often hard to treat due to intrinsic and acquired ARGs commonly carried by this species. This study aimed to understand the potential role of Pseudomonas on food as a reservoir of ARGs and to assess the presence of potentially clinically significant Pseudomonas aeruginosa strains on food. To achieve this, we assessed the genetic relatedness (using whole genome sequencing) and virulence of food-derived isolates to those collected from humans.ResultsA non-specific culturing approach for Pseudomonas recovered the bacterial genus from 28 of 32 (87.5%) retail food samples, although no P. aeruginosa was identified. The Pseudomonas species recovered were not clinically relevant, contained no ARGs and are likely associated with food spoilage. A specific culture method for P. aeruginosa resulted in the recovery of P. aeruginosa from 14 of 128 (11%) retail food samples; isolates contained between four and seven ARGs each and belonged to 16 sequence types (STs), four of which have been isolated from human infections. Food P. aeruginosa isolates from these STs demonstrated high similarity to human-derived isolates, differing by 41–312 single nucleotide polymorphisms (SNPs). There were diverse P. aeruginosa collected from the same food sample with distinct STs present on some samples and isolates belonging to the same ST differing by 19–67 SNPs. The Galleria mellonella infection model showed that 15 of 16 STs isolated from food displayed virulence between a low-virulence (PAO1) and a high virulence (PA14) control.ConclusionThe most frequent Pseudomonas recovered from food examined in this study carried no ARGs and are more likely to play a role in food spoilage rather than infection. P. aeruginosa isolates likely to be able to cause human infections and with multidrug resistant genotypes are present on a relatively small but still substantial proportions of retail foods examined. Given the frequency of exposure, the potential contribution of food to the burden of P. aeruginosa infections in humans should be evaluated more closely.

Lactococcus petauri is a recently described species of the genus Lactococcus. It was reported as an etiological agent of piscine lactococcosis together with Lactococcus garvieae. L. garvieae was already described as an opportunistic pathogen in human infections, with a potential zoonotic role. This paper represents the first report of a human urinary tract infection caused by L. petauri. A 91-year-old man was admitted to the emergency department for a femur fracture consequent to a domestic accident. The fracture was reduced by surgery and a catheterized specimen urine culture revealed a high bacterial load sustained by Gram-positive cocci, identified by Vitek 2 compact as L. garvieae, and subsequently as L. petauri through Internal Transcribed spacer 16S-23S r-RNA amplification. The number of L. petauri infections in humans is expected to rise in the near future mainly due to diagnostic improvement. A dedicated survey on L. garvieae and L. petauri infections in humans should be performed to better understand their role as pathogens and as zoonotic agents.

First isolation of Burkholderia tropica from a neonatal patient successfully treated with imipenem