Abnormal morphology of bacteria in the sputa of patients treated with antibiotics

Abstract

Filaments of Klebsiella pneumoniae were observed by Gram stain in the sputum of a patient with a respiratory infection who was treated with half the usual dose of cefazolin. Identical filaments were observed in vitro when this strain was incubated with subminimum inhibitory concentrations of cefazolin. Large gram-positive cocci containing multiple cross walls were observed by electron microscopy in the sputum of a patient with a respiratory infection who was treated with ampicillin and gentamicin. Antibiotic administration was suspended the night before the sputum was obtained. The ultrastructure of these cocci was very similar to the ultrastructure of Staphylococcus aureus incubated with subminimum inhibitory concentrations of cephaloridine or oxacillin. It was suspected that the low dose of cefazolin and the intermittent therapy with ampicillin resulted in a subminimum inhibitory concentration of antibiotic in the respiratory tract which induced the the abnormal morphology of the bacteria observed in the sputum of both patients. The presence of abnormal forms of bacteria in the specimen of a patient, rather than in the culture of a specimen, has clinical significance.

A high-throughput, whole cell assay to identify compounds active against carbapenem-resistant Klebsiella pneumoniae

“…β-lactam antibiotics, which target peptidoglycan synthesis by associating with penicillin-binding proteins, dramatically alter bacterial cell morphology and are bactericidal [22, 23]. To uncover evidence for a similar mechanism of action, we examined cell morphology by phase contrast microscopy after exposure of a carbapenem-susceptible strain of K .…”

Sub-Optimal Treatment of Bacterial Biofilms

“…The morphology of cells can also be altered by exposing planktonic cells to a sub-lethal concentration of antibiotic, causing a direct effect on the ability to form biofilm. For instance, treating E. coli cells with a sub-inhibitory concentration of piperacillin or a combination of piperacillin and tazobactam resulted in filamentation [ 61 , 62 ]. Generation of the filamentous form of E. coli cells was accompanied by the inhibition of virulence factors, biofilm formation, cell surface hydrophobicity and motility, concordant with a reduction in the pathogenicity observed for the filamentous E. coli in a murine model of intra-abdominal infection [ 62 ].…”

Yersiniosis due to infection byYersinia pseudotuberculosis4b in captive meerkats (Suricata suricatta) in Japan

“…Shape-changed bacilli have often been observed in clinical specimens such as blood, sputum, and urine from human patients receiving antibiotics and are attributed to the pharmacological actions of antibiotics on the bacterial cell wall. 10,11 The presence of abnormal forms of bacteria are indicative of inadequate antibiotic concentrations at the site of infection. 10,11 Shape-changed bacteria may result in a misdiagnosis or cause a misleading negative bacterial culture result due to bacterial cell wall destruction.…”

“…10,11 The presence of abnormal forms of bacteria are indicative of inadequate antibiotic concentrations at the site of infection. 10,11 Shape-changed bacteria may result in a misdiagnosis or cause a misleading negative bacterial culture result due to bacterial cell wall destruction. 11…”