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Comparison of molecular and susceptibility characteristics of CA-MRSA and HA-MRSA among hospital-admitted patients in two main cities of Iran: 1year study

Abstract number: P528

Moghadami M., Mardani M., Amini M.

Objective: Methicillin-resistant Staphylococcus aureus (MRSA) has traditionally been considered a health care-associated pathogen in patients with established risk factors. However, MRSA has emerged in patients without established risk factors.

To characterise epidemiological and microbiological characteristics of community-associated MRSA (CA-MRSA) cases compared with health care-associated MRSA (HA-MRSA) cases in our country this survey was done.

Method: Prospective cohort study was done for patients with MRSA infection identified at 4 medical universities' hospitals in Tehran (capital of Iran) and main hospital in Shiraz (main city in South of Iran) from December, 2007 through September, 2008, comparing CA-MRSA with HA-MRSA cases. Clinical infections associated with either community-associated or health care-associated MRSA, microbiological characteristics of the MRSA isolates including susceptibility testing (MIC Determination by broth method for clindamycin, rifampin, doxycyclin, trimethoprim-sulfamethoxol, tetracycline, ciprofloxacin), and staphylococcal SCCmec genes type was done (by multiplex PCR) were determined.

Results: Of 109 documented MRSA infections, 15 (12%) were community-associated and 94 (85%) were health care-associated. The staphylococcal cassette chromosome mec (SCCmec) types and antimicrobial susceptibility patterns of all MRSA strains were determined. Although community-associated MRSA isolates were more likely to be susceptible to antimicrobial classes, most community-associated infections were initially treated with antimicrobials to which the isolate was nonsusceptible. Most frequent SCCmec in our hospitals was SCCmec-I (56.9%) and least one was SCCmec-III (10.1%) and relevant SCCmec with community was type IV.

CA-MRSA strain were significantly more susceptible to above antibiotics in comparison to HA-MRSA (OR,  5.2; CI, 4.83–5.94) but overall we have very high index of resistance for MRSA as our most sensitive antibiotic was Trimethoprim-Sulfamethaxozol with 42% susceptibility (Table).

Conclusions: Our study, as we know, was first study in Iran about differentiation of different characteristic of CA-MRSA and HA-MRSA. We have very resistant MRSA in our hospitals and this is troublesome for care of patient's most important point in for control of emerging infections is supervision in antibiotic use by infectious control committees.

Also we found as other studies difference in origin of CA-MRSA and HA-MRSA.

Resistance profile of MRSA strains according to epidemiological classification of MRSA

Antimicrobial agentNumber (%)
 HA-MRSACA-MRSATotalP-value
Ciprofloxacin68 (72)5 (33)73 (67)0.003
Cotrimoxazole60 (63)4 (26)64 (58)0.007
Clindamycin73 (77)8 (53)81 (74)0.045
Rifampin63 (67)5 (33)68 (62)0.012
Tetracycline78 (83)6 (40)84 (77)0.00
Erythromycin73 (77)9 (40)79 (72)0.002
Doxycycline58 (90)4 (57)62 (87)0.011

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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