Enhanced bactericidal action of mouse macrophages by subinhibitory concentrations of monobactams

Iida-Tanaka, Kyoko; Tanaka, Terukazu; Irino, Shôzo; Nagayama, Ariaki

doi:10.1093/jac/18.2.239

Cited by 9 publications

(3 citation statements)

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“…Treatment of bacterial infections is closely related not on ly to the direct antibacterial action of antibiot ics but also to the host defence mechanisms such as phagocytes (polymorphonuclear leu kocytes and macrophages) and complement. For these reasons, in vitro studies have been performed regarding the interaction between antibiotics at a sub-MIC and host defence mechanisms [20][21][22]. Wc previously studied the in vitro interaction among cefodizime, bacteria (Escherichia coli and Pseudomonas aeruginosa) and mouse polymorphonuclear leukocytes and macrophages.…”

Section: Introductionmentioning

confidence: 99%

In vitro and in vivo Enhancement of Bactericidal Activity of Phagocytes against Klebsiella pneumoniae treated with Subminimal Inhibitory Concentrations of Cefodizime

Nomura¹,

Nagayama²

1995

Chemotherapy

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The effects of a subminimal inhibitory concentration (sub-MIC) of cefodizime on the bactericidal activity of phagocytes against encapsulated Klebsiella pneumoniae were studied in an in vitro system using an established mouse macrophage cell line, and in an in vivo system using mice in which many phagocytes were induced in the peritoneal cavity. In the in vitro system, the bactericidal activity of mouse macrophages against K. pneumoniae treated with a sub-MIC of cefodizime was significantly enhanced, and was greater than that of cefotaxime or cefoperazone. Significantly more bacteria treated with a sub-MIC of cefodizime were killed by serum complement than those treated with cefotaxime or cefoperazone. In the in vivo system, cefodizime-treated bacteria were phagocytosed and killed by phagocytes in the mouse peritoneal cavity, whereas, cefotaxime- and cefoperazone-treated and untreated bacteria were hardly phagocytosed at all or killed by phagocytes in the mouse peritoneal cavity, and bacterial regrowth was observed 24 h after bacterial challenge. Furthermore, the virulence of K. pneumoniae in mice was reduced more by treatment with cefodizime than with cefotaxime or cefoperazone. These findings indicate that K. pneumoniae treated with a sub-MIC of cefodizime become more susceptible to the bactericidal activity of phagocytes both in vitro and in vivo. This provides evidence that cefodizime at a sub-MIC may act together with the phagocytes against bacterial infections.

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Section: Introductionmentioning

confidence: 99%

In vitro and in vivo Enhancement of Bactericidal Activity of Phagocytes against Klebsiella pneumoniae treated with Subminimal Inhibitory Concentrations of Cefodizime

Nomura¹,

Nagayama²

1995

Chemotherapy

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“…These researchers found that the function of alveolar macrophages rather than a change in the number of these phagocytes in the lungs decreased with age [80]. Subinhibitory concentrations of antibiotics can also increase susceptibility to killing by host macrophages, a phenomenon linked to altered capsule thickness, surface hydrophobicity, and charge [89][90][91].…”

Section: Phagocytes and Host Defense Against K Pneumoniaementioning

confidence: 99%

Innate Host Defense against Klebsiella pneumoniae and the Outlook for Development of Immunotherapies

et al. 2021

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Klebsiella pneumoniae (K. pneumoniae) is a Gram-negative commensal bacterium and opportunistic pathogen. In healthy individuals, the innate immune system is adept at protecting against K. pneumoniae infection. Notably, the serum complement system and phagocytic leukocytes (e.g., neutrophils) are highly effective at eliminating K. pneumoniae and thereby preventing severe disease. On the other hand, the microbe is a major cause of healthcare-associated infections, especially in individuals with underlying susceptibility factors, such as pre-existing severe illness or immune suppression. The burden of K. pneumoniae infections in hospitals is compounded by antibiotic resistance. Treatment of these infections is often difficult largely because the microbes are usually resistant to multiple antibiotics (multidrug resistant [MDR]). There are a limited number of treatment options for these infections and new therapies, and preventative measures are needed. Here, we review host defense against K. pneumoniae and discuss recent therapeutic measures and vaccine approaches directed to treat and prevent severe disease caused by MDR K. pneumoniae.

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“…Te classes of antibiotics used in this study and their mechanisms of action were obtained from previous studies.Class of antibioticsAntibioticsMechanism of actionReferences Penicillin Ampicillin, piperacillin, piperacillin-tazobactam, and cefepime Disrupt the synthesis of the peptidoglycan layer of bacterial cell walls[34] Penicillin combinations Amoxicillin/clavulanate Te second component reduces the efectiveness of some forms of bacterial resistance to the frst component the synthesis of the peptidoglycan layer of bacterial cell walls[36] Carbapenems Imipenem, meropenem…”

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confidence: 99%

Risk Factors of Clonally Related, Multi, and Extensively Drug-Resistant Acinetobacter baumannii in Severely Ill COVID-19 Patients

Ahmed

Abdulrahman

Taha

2023

Canadian Journal of Infectious Diseases and Medical Microbiolog

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Background. The secondary infection of multi and extensively drug-resistant “Acinetobacter baumannii” in severely ill COVID-19 individuals is usually associated with extended hospitalisation and a high mortality rate. The current study aimed to assess the exact incidence rate of A. baumannii coinfection in severely ill COVID-19 patients admitted to intensive care unit (ICUs), to identify the possible mechanism of A. baumannii transfer to COVID-19 patients and to find out their resistance rate against different antibiotics. Methods. Fifty severely ill “COVID-19” individuals on respiratory support were selected with samples being collected from the pharynx. In addition, another 60 samples were collected from the surrounding environment. Bacterial isolates were diagnosed by microbiological cultures and confirmed by “Vitek 2 system” and real-time PCR. The “Vitek 2 Compact system” was used to evaluate these isolates for antimicrobial susceptibility. The recovered isolates’ DNA fingerprints and genetic similarities were performed using ERIC-PCR. Results.Twenty-six samples were tested positive for A. baumannii (20 out of 50 samples taken from patients, 40%; 6 out of 60 swabs from a nosocomial setting, 10%). All A. baumannii strains isolated from the nosocomial sites were clonally related (have the same genetic lineage) to some strains isolated from patients. However, the majority of the patients’ strains were categorised as belonging to the same genetic lineage. Furthermore, “the multi and extensively drug” resistance patterns were seen in all isolates. In addition, total isolates showed resistance to the most commonly tested antibiotics, while none of them was found to be resistant to tigecycline. Conclusion. Secondary “A. baumannii” infection in severely ill “COVID-19” patients is a serious matter, especially when it has one spot of transmission in the ICU as well as when it is extensively drug-resistant, necessitating an immediate and tactical response to secure the issue.

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Enhanced bactericidal action of mouse macrophages by subinhibitory concentrations of monobactams

Cited by 9 publications

References 0 publications

In vitro and in vivo Enhancement of Bactericidal Activity of Phagocytes against <i>Klebsiella pneumoniae </i>treated with Subminimal Inhibitory Concentrations of Cefodizime

In vitro and in vivo Enhancement of Bactericidal Activity of Phagocytes against <i>Klebsiella pneumoniae </i>treated with Subminimal Inhibitory Concentrations of Cefodizime

Innate Host Defense against <b><i>Klebsiella pneumoniae</i></b> and the Outlook for Development of Immunotherapies

Risk Factors of Clonally Related, Multi, and Extensively Drug-Resistant Acinetobacter baumannii in Severely Ill COVID-19 Patients

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