The Effects of Temperature and pH on the Growth of Eight Enteric and Nine Glucose Non‐Fermenting Species of Gram‐Negative Rods

Abstract

We studied the heat resistance and the range of growth temperature 0 gram-negative rods to find one of the bacterial factors governing their infectivity in exogenous and endogenous infections in predisposed patients.Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa, and Acinetobacter calcoaceticus grew equally well at 25, 30, 37, and 42 C. Among other sugar non-fermenting gram-negative rods, six species showed suppressed growth at either or both ends of the incubation temperature range. All the bacterial species tested were killed within 30 min at 60 or 70 C. At 10 C, none of the bacterial strains multiplied, but all survived for 6 hr.Of 17 bacterial species tested, E. coli had the widest range of growth temperature (18-47 C), and also the shortest time necessary for growth to a certain population. Among the sugar non-fermenting rods, A. calcoaceticus had the widest range of growth temperature (20-45 C) and also multiplied rapidly. Pseudomonas strains exhibited slower growth at all temperatures and also had a narrower range of growth temperature than Enterobacteriaceae. Among Pseudomonas species, P. aeruginosa had the widest range of growth temperature (25-42 C) and also showed rapid growth. Pseudomonas cepacia, Achromobacter xylosoxidans, and ALcaligenes faecalis had a narrow range of growth temperature (28-37 C), and Pseudomonas fluorescens, Flavobacterium meningosepticum, and Moraxella grew most rapidly at 30 C.The above results are correlated fairly well with the incidence of clinical cases of infection. The growth attitude of a species of bacteria in response to temperature was considered to be one of the factors affecting the establishment of infection.

Antibiotic and metal resistance in a ST395 Pseudomonas aeruginosa environmental isolate: A genomics approach

“…These features are according to the ones previously reported for this species (Klein et al, 2009;LaBauve and Wargo, 2005;Kumar Deshwal and Kumar, 2013;Tsuji et al, 1982). Regarding the antibiotic resistance phenotype, isolate E67 displayed resistance or intermediate resistance to several antibiotics, namely amoxicillin, the combination of amoxicillin with clavulanic acid, ampicillin, cefotaxime, kanamycin, cephalothin, nalidixic acid, chloramphenicol, rifampicin, aztreonam, imipenem, meropenem and tetracycline.…”

Ecological networking of cystic fibrosis lung infections

“…Indeed, the pH of CF lung secretions has been measured as low as 2.9, 59 is lower than those of healthy controls (exhaled breath condensate average pH: CF = 5.88 and non-CF  = 6.15, 48 ), and is lower during exacerbation. 60, 61 P. aeruginosa , however, including strains recovered from CF lungs, does not grow well below pH 5 62 (Supplementary Fig. S2).…”

Antimicrobial Effects of Plasma-mediated Bipolar Radiofrequency Ablation on Bacteria and Fungi Relevant for Wound Infection

“…At the longest TC exposure time a clear reduction in CFU/ml was seen for all strains, as would be expected with the thermal increase in a small amount of fluid. It is well established that the different strains utilized are sensitive to short exposures to temperatures in the range of approximately 52-70°C (28)(29)(30)(31)(32).…”