BACKGROUND Panton-Valentine leukocidin(PVL)is an exotoxin secreted by Staphylococcus aureus(S.aureus),responsible for skin and soft tissue infections.As a cause of severe necrotising pneumonia,it is associated with a ...BACKGROUND Panton-Valentine leukocidin(PVL)is an exotoxin secreted by Staphylococcus aureus(S.aureus),responsible for skin and soft tissue infections.As a cause of severe necrotising pneumonia,it is associated with a high mortality rate.A rare entity,the epidemiology of PVL S.aureus(PVL-SA)pneumonia as a complication of influenza coinfection,particularly in young adults,is incompletely understood.CASE SUMMARY An adolescent girl presented with haemoptysis and respiratory distress,deteriorated rapidly,with acute respiratory distress syndrome(ARDS)and profound shock requiring extensive,prolonged resuscitation,emergency critical care and venovenous extracorporeal membrane oxygenation(ECMO).Cardiac arrest and a rare complication of ECMO cannulation necessitated intra-procedure extracorporeal cardiopulmonary resuscitation,i.e.,venoarterial ECMO.Coordinated infectious disease,microbiology and Public Health England engagement identified causative agents as PVL-SA and influenza A/H3N2 from bronchial aspirates within hours.Despite further complications of critical illness,the patient made an excellent recovery with normal cognitive function.The coordinated approach of numerous multidisciplinary specialists,nursing staff,infection control,specialist cardiorespiratory support,hospital services,both adult and paediatric and Public Health are testimony to what can be achieved to save life against expectation,against the odds.The case serves as a reminder of the deadly nature of PVL-SA when associated with influenza and describes a rare complication of ECMO cannulation.CONCLUSION PVL-SA can cause severe ARDS and profound shock,with influenza infection.A timely coordinated multispecialty approach can be lifesaving.展开更多
Objective:To identify the pathogenic gene of Panton-Valentine leukocidin in methicillin-resistant Staphylococcus aureus strain isolated from clinical specimens of burn patients in Shaheed Zare Burn Hospital.Methods:A ...Objective:To identify the pathogenic gene of Panton-Valentine leukocidin in methicillin-resistant Staphylococcus aureus strain isolated from clinical specimens of burn patients in Shaheed Zare Burn Hospital.Methods:A total of 104 samples of Staphylococcus were collected and 78 aureus samples were isolated from Zare Hospital patients from November 2016 to July 2017.All isolates were identified using a standard biochemical and laboratory methodology in accordance with CLSI principles,and disk agar diffusion antibiogram were performed to identify methicillin resistant colonies.Then the presence of the Panton-Valentine leukocidin gene was tested by PCR.Results:Of the methicillin-resistant Staphylococcus aureus samples,80%were negative for the Panton-Valentine leukocidin gene,and only 20%of the samples had Panton-Valentine leukocidin gene.Male and female patients showed no significant difference in the positivity rate of Panton-Valentine leukocidin gene(16.12%vs.33.33%)(P=0.25).Besides,there was no significant difference in bacterial resistance or susceptibility to antibiotics between samples with or without the Panton-Valentine leukocidin gene.Conclusions:In recent years,increased resistance has been a serious threat.The resistance or susceptibility of Staphylococcus aureus strains to different antibiotics is different in different geographical locations.展开更多
We previously observed the elicitation of a significant delayed-type hypersensitivity response to the Panton-Valentine leukocidin (PVL) LukS-PV subunit following subcutaneous immunization (Brown et al., Clinical Micro...We previously observed the elicitation of a significant delayed-type hypersensitivity response to the Panton-Valentine leukocidin (PVL) LukS-PV subunit following subcutaneous immunization (Brown et al., Clinical Microbiology and Infection, 2009, 156: 156-164). A LukS-PV-specific cell line (LST) was screened for proliferative responses against a panel of 25 amino acid-long peptides spanning the length of LukS-PV (amino acids 29-312). This analysis demonstrated that stimulation of LST with LukS-PV resulted in significant proliferative responses and adoptive transfer of LST into na?ve mice conferred a LukS-PV-specific DTH response following challenge. Challenge of mice adoptively transferred with LST with peptides 7 (149-173), 8 (169-193) and 14 (289-312) also elicited a measurable DTH response suggesting that these peptides contained T cell epitopes.展开更多
Panton-Valentine leukocidin (PVL) is one of the toxins responsible for increased virulence of <em>Staphylococcus aureus</em>. In school settings where children are in close contact with each other, <em&...Panton-Valentine leukocidin (PVL) is one of the toxins responsible for increased virulence of <em>Staphylococcus aureus</em>. In school settings where children are in close contact with each other, <em>S. aureus</em> strains, including those that may produce PVL, can be transmitted and spread in the community. Twenty-two multi-drug resistant MRSA nasal isolates from children enrolled in five schools in the town of Mariental and the multi-drug resistant American Type Culture Collection MRSA reference strain <em>S. aureus</em> ATCC 33591 (PVL-negative control) were used for molecular assays. Plasmid deoxyribonucleic acid (DNA) of isolates was amplified by polymerase chain reaction (PCR) and amplified PCR products were electrophoresed on a 2.5% (w/v) agarose gel containing 12 μl 0.5 μg/ml ethidium bromide and 1× TAE (Tris-acetate-EDTA) buffer at 90 volts for 50 minutes. The developed gel was viewed for the PVL-associated <em>lukS</em> and <em>lukF</em> genes that amplified at 151 bp and 406 bp, respectively. Our results indicated that seven nasal isolates had PVL toxin gene(s). From the seven isolates, three were tested positive for both <em>lukS</em> and<em> lukF</em>genes, one tested positive for only<em> lukS</em>, and three tested positive for only <em>lukF</em>. Two of the isolates harbouring both<em> lukS</em> and <em>lukF</em> genes shared the same antibiotic resistance pattern and one of them could also produce enterotoxin A. One of the isolates with only <em>lukF </em>gene could produce enterotoxins B and C. These toxin-producing isolates can be expected to be more virulent than non-producers. Children should be educated on the importance of regular handwashing with soap and water to prevent the spread of potentially virulent staphylococci amongst them and the wider community. This work warrants a larger study to be carried out to investigate PVL toxin and its associated infections in <em>Staphylococcus</em> from school children in Namibia.展开更多
Nasal carriage of <i>Staphylococcus aureus</i> has been identified as a risk factor for the development of staphylococcal infections caused by endogenous colonizing strains. Information on the genotypic di...Nasal carriage of <i>Staphylococcus aureus</i> has been identified as a risk factor for the development of staphylococcal infections caused by endogenous colonizing strains. Information on the genotypic diversity of <i>Staphylococcus aureus</i> is relevant for managing epidemiological and clinical challenges resulting from the evolutionary differences of this bacterium. The objective of this study was to determine and compare the molecular diversity of <i>Staphylococcus aureus</i> isolates from three high-risk populations in Yaounde, Cameroon. Molecular analysis confirmed that 95% of 100 tested isolates were <i>S. aureus</i>. The <i>mec</i>A and Panton Valentine-Leukocidin (PVL) genes (<i>lukS/F-PV</i>) were detected in 37% (35/95) and 43% (41/95) of isolates respectively and 18% (17/95) of the isolates harboured both the <i>mec</i>A and <i>lukS/F-PV</i> genes. A mixed distribution of both methicillin sensitive <i>S. aureus</i> (MSSA)/PVL and methicillin resistant <i>S. aureus</i> (MRSA)/PVL strains were detected within the study population. Community associated MRSA accounted for 94% (33/35) of the isolates, further classified into allotypes SCC<i>mec</i> type IV 54% (19/35) and SCC<i>mec</i> type V 40% (14/35), while two isolates were hospital associated SCC<i>mec</i> type II strains. A majority of the isolates harboured a single aggressive gene regulator allele <i>agr</i> type I. Pulsed Field Gel Electrophoresis (PFGE) generated 18 pulsotypes that grouped isolates irrespective of the study population. Multilocus Sequence Typing (MLST) of 12 selected isolates was assigned to six pandemic clonal complexes (CC): CC5 (ST5), CC8 [ST8, (n = 3)], CC15 (ST 15), CC25 (ST 25), CC72 [ST72 (n = 2)] and CC121 [ST 121 (n = 2)] and three atypical sequence types ST 508, ST 699 (CC45) and ST 1289 (CC 88). The study population represents an important reservoir for MRSA, MRSA-PVL and MSSA-PVL which could serve as focal point for further dissemination bringing about significant clinical and epidemiological implications. The predominance of SCC<i>mec</i> IV and <i>agr</i> types in this setting warrants further investigation. Isolates were genetically diverse with MLST indicating that pandemic ST8 was predominant. Detection of atypical STs has provided an insight into the necessity for constant monitoring.展开更多
文摘BACKGROUND Panton-Valentine leukocidin(PVL)is an exotoxin secreted by Staphylococcus aureus(S.aureus),responsible for skin and soft tissue infections.As a cause of severe necrotising pneumonia,it is associated with a high mortality rate.A rare entity,the epidemiology of PVL S.aureus(PVL-SA)pneumonia as a complication of influenza coinfection,particularly in young adults,is incompletely understood.CASE SUMMARY An adolescent girl presented with haemoptysis and respiratory distress,deteriorated rapidly,with acute respiratory distress syndrome(ARDS)and profound shock requiring extensive,prolonged resuscitation,emergency critical care and venovenous extracorporeal membrane oxygenation(ECMO).Cardiac arrest and a rare complication of ECMO cannulation necessitated intra-procedure extracorporeal cardiopulmonary resuscitation,i.e.,venoarterial ECMO.Coordinated infectious disease,microbiology and Public Health England engagement identified causative agents as PVL-SA and influenza A/H3N2 from bronchial aspirates within hours.Despite further complications of critical illness,the patient made an excellent recovery with normal cognitive function.The coordinated approach of numerous multidisciplinary specialists,nursing staff,infection control,specialist cardiorespiratory support,hospital services,both adult and paediatric and Public Health are testimony to what can be achieved to save life against expectation,against the odds.The case serves as a reminder of the deadly nature of PVL-SA when associated with influenza and describes a rare complication of ECMO cannulation.CONCLUSION PVL-SA can cause severe ARDS and profound shock,with influenza infection.A timely coordinated multispecialty approach can be lifesaving.
基金This article was financially supported by Sari Branch,IslamicAzad University with grant number 410.
文摘Objective:To identify the pathogenic gene of Panton-Valentine leukocidin in methicillin-resistant Staphylococcus aureus strain isolated from clinical specimens of burn patients in Shaheed Zare Burn Hospital.Methods:A total of 104 samples of Staphylococcus were collected and 78 aureus samples were isolated from Zare Hospital patients from November 2016 to July 2017.All isolates were identified using a standard biochemical and laboratory methodology in accordance with CLSI principles,and disk agar diffusion antibiogram were performed to identify methicillin resistant colonies.Then the presence of the Panton-Valentine leukocidin gene was tested by PCR.Results:Of the methicillin-resistant Staphylococcus aureus samples,80%were negative for the Panton-Valentine leukocidin gene,and only 20%of the samples had Panton-Valentine leukocidin gene.Male and female patients showed no significant difference in the positivity rate of Panton-Valentine leukocidin gene(16.12%vs.33.33%)(P=0.25).Besides,there was no significant difference in bacterial resistance or susceptibility to antibiotics between samples with or without the Panton-Valentine leukocidin gene.Conclusions:In recent years,increased resistance has been a serious threat.The resistance or susceptibility of Staphylococcus aureus strains to different antibiotics is different in different geographical locations.
文摘We previously observed the elicitation of a significant delayed-type hypersensitivity response to the Panton-Valentine leukocidin (PVL) LukS-PV subunit following subcutaneous immunization (Brown et al., Clinical Microbiology and Infection, 2009, 156: 156-164). A LukS-PV-specific cell line (LST) was screened for proliferative responses against a panel of 25 amino acid-long peptides spanning the length of LukS-PV (amino acids 29-312). This analysis demonstrated that stimulation of LST with LukS-PV resulted in significant proliferative responses and adoptive transfer of LST into na?ve mice conferred a LukS-PV-specific DTH response following challenge. Challenge of mice adoptively transferred with LST with peptides 7 (149-173), 8 (169-193) and 14 (289-312) also elicited a measurable DTH response suggesting that these peptides contained T cell epitopes.
文摘Panton-Valentine leukocidin (PVL) is one of the toxins responsible for increased virulence of <em>Staphylococcus aureus</em>. In school settings where children are in close contact with each other, <em>S. aureus</em> strains, including those that may produce PVL, can be transmitted and spread in the community. Twenty-two multi-drug resistant MRSA nasal isolates from children enrolled in five schools in the town of Mariental and the multi-drug resistant American Type Culture Collection MRSA reference strain <em>S. aureus</em> ATCC 33591 (PVL-negative control) were used for molecular assays. Plasmid deoxyribonucleic acid (DNA) of isolates was amplified by polymerase chain reaction (PCR) and amplified PCR products were electrophoresed on a 2.5% (w/v) agarose gel containing 12 μl 0.5 μg/ml ethidium bromide and 1× TAE (Tris-acetate-EDTA) buffer at 90 volts for 50 minutes. The developed gel was viewed for the PVL-associated <em>lukS</em> and <em>lukF</em> genes that amplified at 151 bp and 406 bp, respectively. Our results indicated that seven nasal isolates had PVL toxin gene(s). From the seven isolates, three were tested positive for both <em>lukS</em> and<em> lukF</em>genes, one tested positive for only<em> lukS</em>, and three tested positive for only <em>lukF</em>. Two of the isolates harbouring both<em> lukS</em> and <em>lukF</em> genes shared the same antibiotic resistance pattern and one of them could also produce enterotoxin A. One of the isolates with only <em>lukF </em>gene could produce enterotoxins B and C. These toxin-producing isolates can be expected to be more virulent than non-producers. Children should be educated on the importance of regular handwashing with soap and water to prevent the spread of potentially virulent staphylococci amongst them and the wider community. This work warrants a larger study to be carried out to investigate PVL toxin and its associated infections in <em>Staphylococcus</em> from school children in Namibia.
文摘Nasal carriage of <i>Staphylococcus aureus</i> has been identified as a risk factor for the development of staphylococcal infections caused by endogenous colonizing strains. Information on the genotypic diversity of <i>Staphylococcus aureus</i> is relevant for managing epidemiological and clinical challenges resulting from the evolutionary differences of this bacterium. The objective of this study was to determine and compare the molecular diversity of <i>Staphylococcus aureus</i> isolates from three high-risk populations in Yaounde, Cameroon. Molecular analysis confirmed that 95% of 100 tested isolates were <i>S. aureus</i>. The <i>mec</i>A and Panton Valentine-Leukocidin (PVL) genes (<i>lukS/F-PV</i>) were detected in 37% (35/95) and 43% (41/95) of isolates respectively and 18% (17/95) of the isolates harboured both the <i>mec</i>A and <i>lukS/F-PV</i> genes. A mixed distribution of both methicillin sensitive <i>S. aureus</i> (MSSA)/PVL and methicillin resistant <i>S. aureus</i> (MRSA)/PVL strains were detected within the study population. Community associated MRSA accounted for 94% (33/35) of the isolates, further classified into allotypes SCC<i>mec</i> type IV 54% (19/35) and SCC<i>mec</i> type V 40% (14/35), while two isolates were hospital associated SCC<i>mec</i> type II strains. A majority of the isolates harboured a single aggressive gene regulator allele <i>agr</i> type I. Pulsed Field Gel Electrophoresis (PFGE) generated 18 pulsotypes that grouped isolates irrespective of the study population. Multilocus Sequence Typing (MLST) of 12 selected isolates was assigned to six pandemic clonal complexes (CC): CC5 (ST5), CC8 [ST8, (n = 3)], CC15 (ST 15), CC25 (ST 25), CC72 [ST72 (n = 2)] and CC121 [ST 121 (n = 2)] and three atypical sequence types ST 508, ST 699 (CC45) and ST 1289 (CC 88). The study population represents an important reservoir for MRSA, MRSA-PVL and MSSA-PVL which could serve as focal point for further dissemination bringing about significant clinical and epidemiological implications. The predominance of SCC<i>mec</i> IV and <i>agr</i> types in this setting warrants further investigation. Isolates were genetically diverse with MLST indicating that pandemic ST8 was predominant. Detection of atypical STs has provided an insight into the necessity for constant monitoring.
