European Journal of Clinical Microbiology and Infectious Diseases

, Volume 24, Issue 9, pp 637–639

Panton–Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus in Germany associated with travel or foreign family origin

Authors

  • J. Maier
    • Institut für Medizinische Mikrobiologie und Hygiene
  • H. Melzl
    • Institut für Medizinische Mikrobiologie und Hygiene
  • U. Reischl
    • Institut für Medizinische Mikrobiologie und Hygiene
  • I. Drubel
    • HygieneKlinikum Fürth
  • W. Witte
    • Referenzzentrum für StaphylokokkenRobert Koch-Institut FB Bakteriologie, Mykologie, Parasitologie
  • N. Lehn
    • Institut für Medizinische Mikrobiologie und Hygiene
    • Institut für Medizinische Mikrobiologie und Hygiene
Brief Report

DOI: 10.1007/s10096-005-0008-8

Cite this article as:
Maier, J., Melzl, H., Reischl, U. et al. Eur J Clin Microbiol Infect Dis (2005) 24: 637. doi:10.1007/s10096-005-0008-8

Until recently, Panton–Valentine leukocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA) strains were considered to be rare in Germany [1, 2]. However, data collected retrospectively (122 cases in the period 1995–2003) and prospectively (127 cases in 2004) for the geographical region of southeast Bavaria indicate that PVL-positive MRSA might be more common than previously acknowledged [3]. In the study presented here, we evaluated 122 patients in whom PVL-positive MRSA was detected in 2004. Nineteen of these patients had either traveled to (or originated from) foreign countries (predominantly in the Middle East) prior to the onset of symptoms or they belonged to a family originating from a Mediterranean country.

The emergence of PVL-positive MRSA has been noted worldwide in patients without common risk factors for nosocomial multidrug-resistant pathogens [4, 5]. Patients typically present with a history of multiple recurrent deep-seated abscesses, often without an obvious point of entry [6]. Necrotizing pneumonia may also occur. In many cases, carrier status or infections are recorded in close contacts of the index case, such as family members, sexual contacts, fellow military recruits, contact-sport participants, or prison inmates.

In the laboratory, PVL-positive MRSA can be distinguished from nosocomial MRSA negative for PVL by a number of phenotypic and genotypic characteristics. Oxacillin resistance is caused by the mecA gene as part of a specific mec-type IV or -type II staphylococcal cassette chromosome [7]. In contrast to MRSA, many PVL-positive MRSA strains isolated in Germany, France or Switzerland are also resistant to fusidic acid (often associated with the far1 gene coding for an efflux mechanism [2, 8]), whereas resistance to other classes of antibiotics is rare. In addition, most strains of PVL-positive MRSA harbor a specific set of pathogenicity factors (e.g., staphylococcal enterotoxin H, bacteriocin bca, and Panton–Valentine leukocidin) [9]. Although the clinical presentation of infection caused by S. aureus might depend on a variety of factors not yet fully understood [10, 11], PVL is likely to play a key role in skin-related infections and necrotizing pneumonia [6]. PVL is a pore-forming toxin causing lysis of granulocytes and macrophages [12, 13]. The presence of PVL genes is demonstrated by PCR testing for lukS/F [6].

In a prospective study starting in January 2004, we collected clinical and epidemiological data from 127 patients with PVL-positive MRSA using a standardized questionnaire in interviews with patients or their physicians. A case was considered community-acquired if, at the time of symptom onset, the patient or close contacts had no connection with a medical institution and none of the following risk factors: open wound, chronic disease, or antibiotic consumption in the preceding 6 months. Otherwise, the case was considered nosocomial. Altogether, 39 community-acquired and 88 nosocomial cases were observed. Of the 88 nosocomial cases, 75 were detected in one single outbreak that was unrelated to all of the other cases, as proven by epidemiological data, a uniform and unique pattern in pulsed-field gel-electrophoresis, and MLST type 22 (data not shown); these cases were excluded from further analysis in this report.

In 19 patients acquisition of PVL-positive MRSA was linked to foreign countries through travel or family connections: nine patients had a history of travel and ten patients had family originating from the Mediterranean region. Fourteen of these 19 cases belonged to the group of 39 community-acquired cases and five belonged to the group of 13 remaining nosocomial cases following exclusion of the outbreak cases. The isolates obtained from these 19 patients were further characterized using multilocus sequence typing (MLST; http://www.mlst.net).

Among the nine patients with a history of travel, the onset of symptoms (mostly multiple or recurrent cutaneous abscesses) occurred either during the journey (n=8) or within 14 days of journey conclusion (n=1) (Table 1). Patient T4, however, was only colonized. It is noteworthy that five of these nine patients had recently returned (or originated) from the Middle East (patients T1–T5). Most often, insect bites were considered by the patients to be the point of entry; however, true primary rather than secondary infection by PVL-positive MRSA may have occurred.
Table 1

Destination (D) or origin (O) and clinical aspects of infection in nine patients with Panton–Valentine leukocidin-positive methicillin-resistant S. aureus and a history of travel

Patient no.

Destination/origin

Purpose of travel

Clinical presentation

Point of entry

Relatedness

Antimicrobial resistance

MLST-type

T1

Dead Sea (D)

Vacation

Abscesses

Insect bites

Married to T1

Oxa, Fus

ST80

T2

Dead Sea (D)

Vacation

Abscesses

Insect bites

Married to T2

Oxa, Fus

ST80

T3

Saudi Arabia (O)

Medical treatment in Germany

Necrotizing pneumoniaa

Post-LTX

Mother of T4 (LTX-recipient)

Oxa, Fus

ST80

T4

Saudi Arabia (O)

Medical treatment in Germany

Colonisation

 

Daughter of T3 (LTX-donor)

Oxa, Fus

ST80

T5

Egypt (D)

Vacation

Abscesses

Insect bites

NR

Oxa, Fus

ST80

T6

England (D)

Visit with host family

Abscesses

Unknown

NR

Oxa, Fus

ST22

T7

Philippines (D)

Work

Abscesses

Insect bites

NR

Oxa, Fus

ST30

T8

USA (O)

U.S. army service

Abscesses

Insect bites

NR

Oxa, Fus, Ery

ST8

T9

Pakistan (O)

Asylum seeker

Abscesses

Unknown

NR

Oxa, Fus

ST80

aLethal

LTX Liver transplant; NR not related; Oxa oxacillin; Fus fusidic acid; Ery erythromycin

The results of MLST are in accordance with previous data on the geographical distribution of MLST types of PVL-positive MRSA [14]. ST80 is known to occur in the Middle East: Although ST80 has also been described in Germany, Switzerland and France, patients T3 and T4 had never previously visited those European countries, and the onset of symptoms in the other patients with this type, either during or after travel to the Middle East, suggests acquisition there. ST22 was presumably acquired by patient T6 in London, where she resided with a host family, but it has also been recorded in Scotland. Correspondingly, ST8, found in patient T8, is one of the major PVL-positive MRSA clones in the USA (Fred Tenover, CDC, personal communication), and ST30, identified in patient T7, has been found in the Pacific region.

Interestingly, another ten PVL-positive MRSA isolates (7 community-acquired, three nosocomial) were noted in patients living in Germany who had family originating from Mediterranean countries (Table 2). The typical geographic distribution of the MLST types found in these cases (ST80, ST22) does not preclude their acquisition in Germany. However, the proportion of community-acquired cases with foreign family contacts (7 of 39) might indicate this population is at special risk. Systematic studies comparing the prevalence of PVL-positive MRSA in different population groups in Germany are needed to address this observation. In the case of the young female patient O2 (Table 2), her mother also suffered from multiple abscesses, but culture was not performed. Following the completion of the study, another two cases with multiple abscesses were detected in a Portuguese family, but isolates for MLST typing were lost.
Table 2

Panton–Valentine leukocidin-positive methicillin-resistant S. aureus in patients with family originating from Mediterranean countries

Patient no.

Country of family origin

Clinical presentation

Point of entry

Relationship

Antimicrobial resistance

MLST type

O1

Greece

Abscesses

Unknown

NR

Oxa, Fus

ST80

O2

Greece

Abscesses

Unknown

NR

Oxa, Fus

ST80

O3

Italy

Joint-prosthesis

Post-operative wound infection

NR

Oxa, Fus

ST80

O4

Turkey

Abscesses

Unknown

Child of O6 and O7

Oxa, Fus

ST22

O5

Turkey

Colonisation

NA

Child of O6 and O7

Oxa

ST22

O6

Turkey

Abscesses

Unknown

Mother of O4 and O5

Oxa

ST22

O7

Turkey

Colonisation

NA

Father of O4 and O5

Oxa

ST22

O8

Turkey

Abscesses

Unknown

Nursea

Oxa, Fus

ST80

O9

Turkey

Abscesses

Unknown

Nursea

Oxa

ST80

O10

Turkey

Abscesses

Unknown

NR

Oxa

ST80

aThe two nurses were part of a nosocomial outbreak on a neonatal ward that involved three personnel and five neonates; screening of parents and personnel did not identify any additional cases (data not shown)

NR No relationship; NA not applicable; Oxa oxacillin; Fus fusidic acid

In conclusion, our observational data demonstrate the polyclonal nature of PVL-positive MRSA strains in a small region in Germany, and it is highly unlikely that this finding is unique to our region. The epidemiological data and results of MLST typing for the nine patients with PVL-positive MRSA and a history of travel suggest that some cases of PVL-positive MRSA infection in Germany are linked to international travel, especially to countries in the Middle East, and they could be misinterpreted as insect bites. The data also indicate an association exists between PVL-positive MRSA infection in patients living in Germany and family originating from Mediterranean countries. PVL-positive MRSA should therefore be suspected in patients with multiple or recurrent skin infections and a recent history of travel, and bacterial culture should be performed. Resistance to fusidic acid in methicillin-resistant S. aureus may also be helpful for identifying PVL-positive MRSA. Unfortunately, community-acquired infections seldom receive microbiologic workup. Detection of PVL-positive MRSA in community-acquired and nosocomial infections is important for initiating appropriate treatment for patients and their contacts as well as for implementing strict infection control measures to protect other patients and personnel.

Acknowledgements

We thank Dr. G. Buchwald (synlab, Weiden, Germany) for providing MRSA isolates suspected to harbor PVL.

Copyright information

© Springer-Verlag 2005