Antibiotic Susceptibility Testing and Genotyping of

Antibiotic Susceptibility Testing and Genotyping of Methicillin Resistant Staphylococcus aureus isolated in the Maternity hospital in Kuwait. Edet E Udo, Noura Al-Sweih.

Department of Microbiology, Faculty of Medicine, Kuwait University. Kuwait. Introduction

Methicillin- resistant Staphylococcus aureus (MRSA) is a major pathogen causing healthcareand community- acquired infections. The Maternity hospital in Kuwait was free of MRSA prior to 2005. However, since 2005 MRSA has been isolated consistently from babies and mothers in the hospital [1].

Objectives

The purpose of this study was to characterize MRSA isolated at the Maternity Hospital to determine their clonal types and their relatedness to MRSA isolated in other hospitals in Kuwait

3. Molecular typing of MRSA isolates

4. MRSA among healthcare workers

Molecular typing classified the MRSA isolates into three SCCmec types (III, IV and V), 10 PFGE types and subtypes, 21 sequence type and 31 Spa types.

MRSA strains isolated from healthcare workers in different hospital departments are summarized in Table 2

SCCmec typing and MLST characterized the MRSA isolates into 11 clonal complexes and 23 genotypes as shown in Table 1. Figure 3 shows the distribution of PFGE types of the isolates. PFGE types 1 (CC5), 2 (CC22) and 3 (CC8) constituted 77.6% of the isolates.

35

Materials & Methods

33

Bacterial strains A total of 103 MRSA obtained from 74 neonates and 29 adults including mothers and healthcare workers between 2006 and 2010. Antibiotic Susceptibility testing

5

Antibiotic Susceptibility testing was performed as described previously [2]. Molecular typing

1

Results

MRSA Clones

#

CC1

ST1-IV-t127 ST1-V-t2962 ST772-V-t657 ST5-V-t067 ST5-V-t688 ST5-V-t002 ST5-V-t2302 ST1462-IV-t690 ST194-IV-t6892 ST5-IV-t2302 ST5-V-t1084 ST5-V-t651 ST5-V-6265 ST5-IV-t214 ST935-V-t1084 ST627-IV-t1340 ST1317-V-t1548 ST6-IV-t6269 ST932-IV-t304 ST932-IV-t657 ST239-III-t860

2 2 1 10 5 4 4 3 3 2 2 1 1 1 1 1 1 4 2 1 4

ST239-III-t4410 ST241-III-t037 ST9-V-t5801 ST22-IV-t223 ST22-IV-t1084 ST22-IV-t309 ST60-IV-t3935 ST77-IV-t339 ST1055-IV-t127 ST80-IV-t044

1 1 1 15 1 7 5 1 1 7

ST2148-IV-t2810 ST97-V-t359 ST97-V-t224 ST97-V-t1234 ST121-V-t308

1 3 1 2 1

CC5

18 13

11

9

7

4

4

CC6

Figure 1. Sources of MRSA isolates

2. Antibiotic resistance of MRSA isolates

All MRSA isolates were susceptible to vancomycin, teicoplanin and linezolid. The prevalence of resistance to other antibiotics are presented in Figure 2.

CC8

CC9 CC22

90.3

CC30 CC80 46.6

CC88 CC97

32 22.3

Kan

5

CC

37

Gen

4

6

2

2

1

1

7

8

9

10

Table 1. Distribution of MRSA clones

1. Sources of MRSA isolates MRSA were isolated from clinical samples summarized in Figure 1.

Pen

3

4

Figure 3. PFGE types of MRSA isolates.

Pulsed-field gel electrophoresis (PFGE) [3], SCCmec typing [4], spa typing [5], multilocussequence typing (MLST) [6] and PVL detection [7] were performed as described previously.

40.8

2

Tp

Cip

16.5

Fa

19.4

Tet

15.5

Em

11.6

Sm

PVL Antibiotic resistance profiles (# resistant strains). Tet + Km, Tp + Gm, Km, Tp Gm, Km, Em (1), Clin (1) Km (1), Cm (1), Tet Gm (3), Km (3), Em (1), Clin (1) Gm, Km + Tet (2), Em (1), Clin (1) + Km (1), Cip (2), Tp (2) + Em (1), Clin (1) Gm, Km, Tp, Fa GM, km, Em, Clin, Tet, Fa, Cip Gm, Km Km, Cip Gm, Km + TP Em, Clin, Tp, Fa, Cip Gm, KM, Sm, Em, Clin, Tet, Tp, Fa, Cip, Mup (3) GM, KM, Sm,Tet, Em, Clin, Tp, Cip Gm, Km, Sm, Em, Clin, Tp, Cip Gm, Km, Fa Tp (10), Tet (2), Km (2), Cip(3) + Gm, Km, Tp + Gm (4), Km (4), Tp (2), Cip. + Tet (1), Tp (4) + + Tp + Km (4), Sm (5), Tet (1), Fa (4), Tp (2), Em (1), Clin (1) Tet, Tp + Gm, Km, Fa, Tp (1), Cip (1) Em, Clin Tet (1) + Tet

2.9

CC121

Mup

Abbreviations: CC, Clonal complex; Gm, gentamicin; Km,

Figure 2. Antibiotic resistance (%) of MRSA isolates

Table 2. MRSA clones among Healthcare workers

1 2 3 4 5 6 7 7 9 10

12 8

Nursing staff in the neonatal ward were colonized mostly by MRSA belonging to CC5.

kanamycin; Sm, streptomycin; Em, erythromycin; Clin, clindamycin; Cip, ciprofloxacin;Tet, tetracycline; Tp, trimethoprim; Fa, fusidic acid; Mup, high-level mupirocin.

Occupation

Source

MRSA clone

Receptionist 1 Lab. Technologist 1 Respiratory Technician Lab. Technologist 2 Receptionist 2 Receptionist 2 Receptionist 3 IC*. Staff1 IC. Staff3 IC. Staff7 IC. Staff 19

Wound Nasal Wound HVS Wound HVS Wound Nasal Nasal Nasal Nasal

ST80-IV-t044 ST22-IV-t223 ST22-IV-t123 ST80-IV-t044 ST1462-IV-t690 ST1462-IV-t690 ST22-IV-t223 ST5-V-t2303 ST5-V-t688 ST5-V-t2303 ST5-V-t651

11 IC. Staff 26 Nasal ST5-V-t002 Abbreviations: HVS, high vaginal swab. *IC, Infection control screening of staff nurses in neonatal ward.

Summary and Conclusions The majority of MRSA isolates belonged to clonal complexes, CC5, CC22, CC80, CC6, CC8 and CC97. The most common genotype, ST22-IV-t223, was obtained from neonates, adult patients and workers in the hospital. The only mother-neonate pair identified during this study carried the same strain that belonged to ST6-IV-t6269. The isolates were susceptible to vancomycin, teicoplanin and linezolid. Whereas the CC8 isolates expressed multiresistance, the CC6 isolates were susceptible to the non betalactam agents tested. The MRSA population in the Maternity hospital consisted of clones that were similar to those isolated in other hospitals in Kuwait such as ST239, ST22 and ST80, and some novel ones such as ST60, ST77 and ST9. References 1. Udo EE, Al-Sweih N, Dhar R. et al., Med Princ Pract 2008; 17: 71-75. 2. CLSI. 2012. M100-S22, 32. 3. Udo EE, Farook VS, Mokadas, EM. et al., Int J Infect Dis 1999; 3: 82-87. 4. Zhang K., McClure, J-A., Elsayed, S., et al. J Clin Microbiol 2005; 43:5026-33. 5. Harmsen D, Claus H, Witte W, et al., J Clin Microbiol 2003; 41: 5442-5448. 6. Enright MC, Day NP, Davies J, et al. J Clin Microbiol 2000; 38: 1008-1015. 7. Lina G, Piemont Y, Godail-Gamot F, et al. Clin Infect Dis 1999; 29: 1128-1132.

Acknowledgment The study was supported by Grant No, YM 02/12 from Research Sector, Kuwait University. Kuwait.