Cockroaches as potential vectors of nosocomial infections.

OBJECTIVE

To determine the possible role of cockroaches in the epidemiology of nosocomial infections.

DESIGN

Epidemiologic investigation of bacteria and fungi in cockroaches and evaluation of the antibiotic resistance of the bacteria isolated from the insects.

SETTING

Ninety hospitals in Kaohsiung City and Kaohsiung County in Taiwan.

METHODS

Cockroaches were collected in clinical and nonclinical areas and microorganisms were isolated from their external surface and alimentary tract. The susceptibilities of Staphylococcus aureus, Enterococcus species, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Serratia marcescens, and Proteus species to 17 antibiotics were tested.

RESULTS

Cockroach infestation was found in 46.7% of the hospitals studied. Two hundred three cockroaches were collected (139 Periplaneta americana and 64 Blattella germanica). Periplaneta americana was found more often in nonclinical areas (64.5%) and B. germanica in clinical areas (78.1%). There was no statistically significant difference between Periplaneta americana (98.6%) and B. germanica (96.9%) regarding overall isolation rate (P > .05). However, 33 species of bacteria and 16 species of fungi were isolated from Periplaneta americana and only 23 and 12, respectively, from B. germanica. Resistance to ampicillin (13.7% to 100%), chloramphenicol (14.3% to 71.4%), tetracycline (14.3% to 73.3%), and trimethoprim-sulfamethoxazole (14.3% to 57.1%) was found in two gram-positive and five gram-negative bacteria.

CONCLUSION

Because cockroach infestation occurred in more than 40% of the hospitals and nearly all of the cockroaches harbored bacteria with multidrug resistance and fungi, cockroaches may play a potential role in the epidemiology of nosocomial infections in those hospitals.