Review Reports - A Case of Pseudomonas straminea Blood Stream Infection in an Elderly Woman with Cellulitis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

line 21; remove the phrase 'further analysation'. recast to 'morpho-molecular characterisation and virulence demonstration in a Galleria mellonella model' line 27-28; rephrase 'other Pseudomonas spp' line 31; rephrase 'have been reported' line 33; rephrase 'like other Pseudomonas ....' line 34-35; 'motile bacterium (3). First isolated from Japanese rice plantations, it was formerly named Pseudomonas ochracea' line 38; '... sequence. it is also phylogenetically .....' remove the word 'furthermore', use the word 'also' line 61; 'allergy to penicillin...' line 65; 'as cellulitis...' line 66; remove the word 'with' line 73-75; recast sentence without the repetitive use of the word 'increase' line 77-81; recast line 86; 'isolated', remove word reported line 87; how many days please? Table 1 title showed be recasted, and a description key should be added at the bottom for brief explanation and abbreviations line 233; same as line 86 above line 236; 'therapeutic' line 238; 'likely' line 238-239; delete 'with respect ........... characterisation' line 248; delete 'with respect to her age.... ).' line 267-269; recast

Comments on the Quality of English Language

Author Response

Comments 1
line 21; remove the phrase 'further analysation'. recast to 'morpho-molecular characterisation and virulence demonstration in a Galleria mellonella model'

Response1

We thank the reviewer for this remark and changed the phrase accordingly. However, in order to ensure consistency with respect to UK/US english we stick to write characterization instead of characterisation, as this word appears several times in our manuscript (including references).

Comments 2

line 27-28; rephrase 'other Pseudomonas spp'

Response 2

done

Comments 3

line 31; rephrase 'have been reported'

Response 3

Done

Comments 4

line 33; rephrase 'like other Pseudomonas ....'

Response 4

Done

Comments 5

line 34-35; 'motile bacterium (3). First isolated from Japanese rice plantations, it was formerly named Pseudomonas ochracea'

Response 5

Done

Comments 6

line 38; '... sequence. it is also phylogenetically .....' remove the word 'furthermore', use the word 'also'

Response 6

Done

Comments 7

line 61; 'allergy to penicillin...'

Response 7

Done

Comments 8

line 65; 'as cellulitis...'

Response 8

Done

Comments 9

line 66; remove the word 'with'

Response 9

Done

Comments 10

line 73-75; recast sentence without the repetitive use of the word 'increase'

Response 10

Done

Comments 11

line 77-81; recast

Response 11

These lines include the description of the Penecillin allergy of the patient, which was also addressed by another reviewer. We changed the sentence for more clarity now reading:

"Since the patient reported a not well-defined allergy to penicillin, cefotaxime was initiated to avoid even unlikely risks for allergic complications. Soon after switching to cefotaxime, P. straminea was isolated from one aerobic blood culture from the CVC implantation and from a bacterial swab from the ulcer on the dorsum of the right hand (Fig. 1)."

Comments 12

line 86; 'isolated', remove word reported

Response 12

Done

Comments 13

line 87; how many days please?

Response 13

We deleted the unspecified description "within a few days". To specify recovery time more clearly one sentence (previous version line 91-93 now 86-88) was changed in its position "Ceftazidime treatment was applied for a total of 6 days until a full recovery from the bacterial infection was seen, monitored by inpatient visits and laboratory values."

Comments 14

Table 1 title showed be recasted, and a description key should be added at the bottom for brief explanation and abbreviations

Response 14

A title was added and the position of the description key was changed to the bottom of the table

Comments 15

line 233; same as line 86 above

Response 15

Done

Comments 16

line 236; 'therapeutic'

Response 16

Done

Comments 17

line 238; 'likely'

Response 17

Done

Comments 18

line 238-239; delete 'with respect ........... characterisation'

Response 18

Done

Comments 19

line 248; delete 'with respect to her age.... ).'

Comments 19

Done

Comments 20

line 267-269; recast

Response 20

Done

Reviewer 2 Report

Comments and Suggestions for Authors

Peer review of "A Case of Pseudomonas straminea Blood Stream Infection in an Elderly Woman with Cellulitis"

The authors report a case of skin and soft tissue infection complicated by bacteremia with Pseudomonas straminea isolated from blood and wound (skin ulcer) cultures. The host is a in an elderly patient with multiple chronic dermatologic and vascular conditions (chronic venous insufficiency, atopic dermatitis, and psoriasis), who was receiving apremilast. Overall, the manuscript is well-written and makes a compelling case that P. straminea, usually an environmental bacteria of low virulence not previously reported to cause invasive infection in humans, may indeed invade and overwhelm the innate immune system in patients predisposed by frailty, poor skin integrity, immunocompromising medications, etc. Their microbiological identification and characterization of bacterial virulence in vivo in a Galleria mellonella model went beyond the usual case report and deserve commendation. I have a couple of questions and some suggestions (below):

Questions:

Q1. Did the authors consider risk-stratification of the penicillin allergy with a validated methodology such as the "PEN-FAST questionnaire"? In the future this practice may facilitate de-labeling the reported allergy, as most reported allergies are not corroborated by penicillin skin testing (i.e. they are false reports).

Q2. Why such a low dose of clindamycin (clindamycin, 600 mg/day, 1-1-1)? Rather than 600 mg per day, it should be 600 to 900 mg per dose every 8 hours. What the authors report in the manuscript can be interpreted to be 200 mg per dose, far below recommended for SSTI (skin and soft tissue infections): 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):147-159. doi:10.1093/cid/ciu296 [PubMed 24947530]

Q3. The regimen of "ceftazidime (2 g/day, 1-1-1)" should be clarified. For gram negative bacteremia, the dose should be 2 g every 8 hours. This is not trivial, as the isolate antibiotic susceptibility in Table 1 shows the Pseudomonas straminea to be Intermediate, NOT susceptible as stated in the text. If indeed susceptible, this should be clarified.

Suggestions:

Line 21 - change "analyzation" to "analysis"

Line 27 - change "Except from" to "Except for"

Line 33 - change "Alike" to "Like"

Multiple Lines - Change "regime" to "regimen"

Comments on the Quality of English Language

Needs minor review and edits. There are few grammatical and syntax errors. Overall, it is well written.

Author Response

Comments 1

Response 1

We thank the reviewer for his comments and the opportunity to improve our manuscript

Comments 2

Did the authors consider risk-stratification of the penicillin allergy with a validated methodology such as the "PEN-FAST questionnaire"? In the future this practice may facilitate de-labeling the reported allergy, as most reported allergies are not corroborated by penicillin skin testing (i.e. they are false reports).

Response 2

We thank the reviewer for this comment. Unfortunately the PEN-FAST questionnaire was not used for clinical decision making in this particular patient.

Comment 3

Why such a low dose of clindamycin (clindamycin, 600 mg/day, 1-1-1)? Rather than 600 mg per day, it should be 600 to 900 mg per dose every 8 hours. What the authors report in the manuscript can be interpreted to be 200 mg per dose, far below recommended for SSTI (skin and soft tissue infections): 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):147-159. doi:10.1093/cid/ciu296 [PubMed 24947530]

Response 3

We thank the reviewer for this comment and corrected this mistake. We verified the dosage of the patient with the patient record and corrected this accordingly. We think the "/day" was added during editing of the manuscript and consider this as a typo.

Comment 4

The regimen of "ceftazidime (2 g/day, 1-1-1)" should be clarified. For gram negative bacteremia, the dose should be 2 g every 8 hours. This is not trivial, as the isolate antibiotic susceptibility in Table 1 shows the Pseudomonas straminea to be Intermediate, NOT susceptible as stated in the text. If indeed susceptible, this should be clarified.

Response 4

We also added the EUCAST I definition to the sentence for more clarity as we (as indicated in text and table several times) do not follow the "I"-definition as intermediate, but the EUCAST definition were "I" means susceptible with dose recommendation.

Comments 5

Line 21 - change "analyzation" to "analysis"

Response 5

Changed according to Rev1

Comments 6

Line 27 - change "Except from" to "Except for"

Response 6

Done

Comments 7

Line 33 - change "Alike" to "Like"

Response 7

Done

Comments 8

Multiple Lines - Change "regime" to "regimen"

Response 8

Done

Reviewer 3 Report

Comments and Suggestions for Authors

The authors investigated a strain of Pseudomonas straminea isolated from the blood and skin ulcer of an elderly woman with atopic dermatitis and psoriasis, who developed acute cellulitis in both arms necessitating hospitalization.

The Pseudomonas straminea strain exhibited a wild-type antimicrobial susceptibility profile. Furthermore, the study demonstrated that injections with Pseudomonas straminea had no detrimental effects on Galleria mellonella larval survival.

Overall, while the case report is informative, the authors are encouraged to enhance the clarity of their figures. Specifically, they should revise the titles of the figures to be more declarative, particularly Figure 3.

Comments on the Quality of English Language

Author Response

Comments 1

he authors investigated a strain of Pseudomonas straminea isolated from the blood and skin ulcer of an elderly woman with atopic dermatitis and psoriasis, who developed acute cellulitis in both arms necessitating hospitalization.

The Pseudomonas straminea strain exhibited a wild-type antimicrobial susceptibility profile. Furthermore, the study demonstrated that injections with Pseudomonas straminea had no detrimental effects on Galleria mellonella larval survival.

Response 1

We thank the Reviewer for this comment

Comments 2
Overall, while the case report is informative, the authors are encouraged to enhance the clarity of their figures. Specifically, they should revise the titles of the figures to be more declarative, particularly Figure 3.

Response2 (Fig1)

The initial version:

"Figure 1. Clinical presentation of the patient with cellulitis affecting the entire left arm and an ulcer on the dorsum of the right hand:"

We have discussed how to change the title also in accordance to the journal guidelines for more clarity. However, we did not change the title as we think it is suitable and declarative

Response 2 (Fig2)

The initial version:

"Figure 2. Growth of P. straminea on Columbia blood agar, macroscopic and microscopic appearance:"

The sentence was changed to:

"Colony Morphology and microscopic morphology of Pseudomonas straminea"

Response 2 (Fig3)

The initial version was

"Figure 3. Survival of G. mellonella larvae"

The revised version:

"Kaplan-Meier survival curves of Galleria mellonella larvae following injections with either Pseudomonas straminea or Pseudomonas aeruginosa."